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Researchers at UNIGE have demonstrated the entanglement between 16 million atoms in a crystal crossed by a single photon, confirming the theory behind the quantum networks of the future
Quantum theory is unequivocal: it predicts that a vast number of atoms can be entangled and intertwined by a very strong quantum relationship even in a macroscopic structure.
Until now, however, experimental evidence has been mostly lacking, although recent advances have shown the entanglement of 2,900 atoms. Scientists at the University of Geneva (UNIGE), Switzerland, recently reengineered their data processing, demonstrating that 16 million atoms were entangled in a one-centimetre crystal. Find out all about their research in the journal Nature Communications.
The laws of quantum physics allow to emit signals and immediately detect when they are intercepted by a third party. This property is crucial for data protection, especially in the encryption industry, which can now guarantee that customers will be aware of any interception of their messages. These signals also need to be able to travel long distances using some rather special relay devices, known as quantum repeaters: crystals whose atoms are entangled and unified by a very strong quantum relationship.
When a photon penetrates this small crystal block enriched with rare earth atoms and cooled to 270 degrees below zero (barely three degrees above absolute zero), entanglement is created between the billions of atoms it traverses. This is explicitly predicted by the theory, and it is exactly what happens as the crystal fulfils its function and re-emits -- without reading the information it has received -- in the form of a single photon.
Light analysis: the keystone of the research
It is relatively easy to entangle two particles: splitting a photon, for example, generates two entangled photons that have identical properties and behaviours. «But,» explains Florian Fröwis, a researcher in the applied physics group in UNIGE's science faculty, «it's impossible to directly observe the process of entanglement between several million atoms since the mass of data you need to collect and analyse is so huge.» As a result, Fröwis and his colleagues chose a more indirect route, pondering what measurements could be undertaken and which would be the most suitable ones.
They examined the characteristics of light re-emitted by the crystal, as well as analysing its statistical properties and the probabilities, following two major avenues: that the light is re-emitted in a single direction rather than radiating uniformly from the crystal; and that it is made up of a single photon. In this way, the researchers succeeded in showing the entanglement of 16 million atoms when previous observations had a ceiling of a few thousand.
In a parallel work, scientists at University of Calgary, Canada, demonstrated entanglement between many large groups of atoms. «We haven't altered the laws of physics,» points out Mikael Afzelius, a member of Professor Nicolas Gisin's applied physics group. «What has changed is how we handle the flow of data.»
Particle entanglement is a prerequisite for the quantum revolution that is on the horizon, which will also affect the volumes of data circulating on the networks of the future together with the power and operating mode of quantum computers. Everything, in fact, depends on the relationship between two particles at the quantum level -- a relation that is much stronger than the simple correlations proposed by the laws of traditional physics.
Two socks in the quantum world
Although the concept of entanglement can be hard to grasp, it can be illustrated using two socks! Imagine a physicist who always wears two socks of different colours. When you spot a red sock on his right ankle, you also immediately learn something about the left sock: it is not red. There is a correlation, in other words, between the two socks. This is a reasonably prosaic and quite intuitive occurrence; but when we switch to the world of quantum physics, a new type of correlation -- infinitely stronger and more mysterious -- emerges: entanglement. Now, imagine there are two physicists in their own laboratories, with a great distance separating the two. Each scientist has a quantum particle, a photon, for example.
If these two photons are in an entangled state, the physicists will see non-local quantum correlations, which conventional physics is unable to explain. They will find that the polarisation of the photons is always opposite (as with the socks in the above example), and that the photon has no intrinsic polarisation. The polarisation measured for each photon is, therefore, entirely random and fundamentally indeterminated before being measured. What we are dealing with here is an unsystematic phenomenon that occurs simultaneously in two locations that are far apart... and this is the mystery of quantum correlations!
Florian Fröwis | EurekAlert!
What happens when we heat the atomic lattice of a magnet all of a sudden?
18.07.2018 | Forschungsverbund Berlin
Subaru Telescope helps pinpoint origin of ultra-high energy neutrino
16.07.2018 | National Institutes of Natural Sciences
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
18.07.2018 | Materials Sciences
18.07.2018 | Life Sciences
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Place the digits 1 to 9 into the circles so that each side of the triangle adds to the same total.
There are 44 people coming to a dinner party. There are 15 square tables that seat 4 people. Find a way to seat the 44 people using all 15 tables, with no empty places.
Mrs Morgan, the class's teacher, pinned numbers onto the backs of three children. Use the information to find out what the three numbers were.
There are 78 prisoners in a square cell block of twelve cells. The clever prison warder arranged them so there were 25 along each wall of the prison block. How did he do it?
Fill in the missing numbers so that adding each pair of corner numbers gives you the number between them (in the box).
Katie had a pack of 20 cards numbered from 1 to 20. She arranged the cards into 6 unequal piles where each pile added to the same total. What was the total and how could this be done?
Put the numbers 1, 2, 3, 4, 5, 6 into the squares so that the numbers on each circle add up to the same amount. Can you find the rule for giving another set of six numbers?
Fill in the numbers to make the sum of each row, column and diagonal equal to 34. For an extra challenge try the huge American Flag magic square.
Cassandra, David and Lachlan are brothers and sisters. They range in age between 1 year and 14 years. Can you figure out their exact ages from the clues?
Place the numbers 1 to 10 in the circles so that each number is the difference between the two numbers just below it.
I was looking at the number plate of a car parked outside. Using my special code S208VBJ adds to 65. Can you crack my code and use it to find out what both of these number plates add up to?
Using the statements, can you work out how many of each type of rabbit there are in these pens?
In this problem you have to place four by four magic squares on the faces of a cube so that along each edge of the cube the numbers match.
The clockmaker's wife cut up his birthday cake to look like a clock face. Can you work out who received each piece?
There were chews for 2p, mini eggs for 3p, Chocko bars for 5p and lollypops for 7p in the sweet shop. What could each of the children buy with their money?
Can you draw a continuous line through 16 numbers on this grid so that the total of the numbers you pass through is as high as possible?
This 100 square jigsaw is written in code. It starts with 1 and ends with 100. Can you build it up?
There are three buckets each of which holds a maximum of 5 litres. Use the clues to work out how much liquid there is in each bucket.
A dog is looking for a good place to bury his bone. Can you work out where he started and ended in each case? What possible routes could he have taken?
Use the information to work out how many gifts there are in each pile.
Strike it Out game for an adult and child. Can you stop your partner from being able to go?
Start by putting one million (1 000 000) into the display of your calculator. Can you reduce this to 7 using just the 7 key and add, subtract, multiply, divide and equals as many times as you like?
Can you use the information to find out which cards I have used?
Have a go at this well-known challenge. Can you swap the frogs and toads in as few slides and jumps as possible?
Can you make dice stairs using the rules stated? How do you know you have all the possible stairs?
On the table there is a pile of oranges and lemons that weighs exactly one kilogram. Using the information, can you work out how many lemons there are?
Using the numbers 1, 2, 3, 4 and 5 once and only once, and the operations x and ÷ once and only once, what is the smallest whole number you can make?
What can you say about these shapes? This problem challenges you to create shapes with different areas and perimeters.
All the girls would like a puzzle each for Christmas and all the boys would like a book each. Solve the riddle to find out how many puzzles and books Santa left.
Your challenge is to find the longest way through the network following this rule. You can start and finish anywhere, and with any shape, as long as you follow the correct order.
Rocco ran in a 200 m race for his class. Use the information to find out how many runners there were in the race and what Rocco's finishing position was.
Peter, Melanie, Amil and Jack received a total of 38 chocolate eggs. Use the information to work out how many eggs each person had.
On the planet Vuv there are two sorts of creatures. The Zios have 3 legs and the Zepts have 7 legs. The great planetary explorer Nico counted 52 legs. How many Zios and how many Zepts were there?
Kate has eight multilink cubes. She has two red ones, two yellow, two green and two blue. She wants to fit them together to make a cube so that each colour shows on each face just once.
Find out why these matrices are magic. Can you work out how they were made? Can you make your own Magic Matrix?
Sam sets up displays of cat food in his shop in triangular stacks. If Felix buys some, then how can Sam arrange the remaining cans in triangular stacks?
Nine squares with side lengths 1, 4, 7, 8, 9, 10, 14, 15, and 18 cm can be fitted together to form a rectangle. What are the dimensions of the rectangle?
Using only six straight cuts, find a way to make as many pieces of pizza as possible. (The pieces can be different sizes and shapes).
Use your addition and subtraction skills, combined with some strategic thinking, to beat your partner at this game.
The discs for this game are kept in a flat square box with a square hole for each disc. Use the information to find out how many discs of each colour there are in the box.
A shunting puzzle for 1 person. Swop the positions of the counters at the top and bottom of the board.
Skippy and Anna are locked in a room in a large castle. The key to that room, and all the other rooms, is a number. The numbers are locked away in a problem. Can you help them to get out?
You have two sets of the digits 0 – 9. Can you arrange these in the five boxes to make four-digit numbers as close to the target numbers as possible?
Mr McGregor has a magic potting shed. Overnight, the number of plants in it doubles. He'd like to put the same number of plants in each of three gardens, planting one garden each day. Can he do it?
Find another number that is one short of a square number and when you double it and add 1, the result is also a square number.
Put operations signs between the numbers 3 4 5 6 to make the highest possible number and lowest possible number.
Use the 'double-3 down' dominoes to make a square so that each side has eight dots.
There are a number of coins on a table. One quarter of the coins show heads. If I turn over 2 coins, then one third show heads. How many coins are there altogether?
Amy's mum had given her £2.50 to spend. She bought four times as many pens as pencils and was given 40p change. How many of each did she buy?
In 1871 a mathematician called Augustus De Morgan died. De Morgan made a puzzling statement about his age. Can you discover which year De Morgan was born in? | <urn:uuid:71815185-57db-47a9-bfde-2861ced2b6de> | 3.03125 | 1,647 | Tutorial | Science & Tech. | 77.695215 | 95,515,138 |
200 meters below Idaho, bacteria are living on basalt.
A new type of Earth ecosystem could be found on other planets.
Scientists have found a community of microbes unlike anything else on Earth. Conditions in this ecosystem could mimic those on Earth when life began, and might exist elsewhere in today’s Solar System.
Home to the microbes is a hot spring 200 metres beneath the US state of Idaho. Their lives owe nothing to the Sun. They generate energy by combining hydrogen from rocks with carbon dioxide, releasing methane as a by-product. These ’methanogens’ belong to an ancient group related to bacteria, called the Archaea.
Life - in space and time
Biologists have speculated for many years that hydrogen-powered ecosystems could exist beneath the ground. The methanogen community suggests they were right, says astronomer and astrobiologist Richard Taylor of the Probability Research Group in London.
"As long as there’s subsurface water and enough chemical fuel, you can get microbial life," says Taylor. He thinks that life began in such environments: "It’s life on the surface that’s unusual," he says.
Many bodies in the Solar System and the Universe could harbour similar conditions. "I suspect it’s going to turn out that life is extremely common," says Taylor.
Mars and Jupiter’s moon Europa have both been suggested as places where life could exist on hydrogen, today or in the past. If this is so, says microbiologist Julian Hiscox of the University of Reading, UK, it will be several kilometres below the surface, well beyond the reach of any investigations so far.
Probing these environments is going to cost "an awful lot of money", warns Hiscox. A cheaper alternative, he says might be to look for biologically produced methane in martian meteorites on Earth.
Also, Hiscox says, the geological activity necessary to produce hydrogen may have stopped long ago on Mars, and be absent altogether on Europa.
The finding may give us an insight into life in time as well as space. Chapelle thinks that hydrogen may have been accessible and abundant enough on the young Earth to provide the energy for the earliest life.
JOHN WHITFIELD | © Nature News Service
Scientists uncover the role of a protein in production & survival of myelin-forming cells
19.07.2018 | Advanced Science Research Center, GC/CUNY
NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
20.07.2018 | Power and Electrical Engineering
20.07.2018 | Information Technology
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Any info? Well, double buffering means that you draw an animation frame to an off-screen buffer, and then blit the buffer to video memory all at once. It is used to make animations look smoother. You can also draw to a portion of video-memory which is at that time not displayed on screen, and then simply flip the page to that section of memory when the frame is done. This is called page flipping (... , and is usually more efficient than a buffer in main memory (unless you draw a pixel more than, say, twice on average).As for QuickBasic, as far as I know you can only use page flipping in screen 9, unless you write your own graphics library in another language. A main-memory buffer is rather complicated and not very efficient, because you run into one or several of the following problems:- Without using the graphics PUT statement, you will probably not be able to blit to screen at an acceptable rate (even PUT itself is rather slow).- If you do use PUT, it is quite difficult to draw into the off-screen array, due to the different formats of these images and the limitations of QuickBasic.- With or without PUT, you are likely to bump into the 64k-size limit.
If there is anything else you'd like to know, or some things are not clear yet, feel free to ask
It looks like you're new here. If you want to get involved, click one of these buttons! | <urn:uuid:afa4d490-825a-48cf-90da-052a83d9430c> | 2.703125 | 305 | Comment Section | Software Dev. | 58.295735 | 95,515,158 |
Amplifying Climate Feedbacks
The IPCC is called the voice of climate change science.
The 2014 IPCC AR5 all important SPM (Summary for Policy Makers) reports were cursory on feedbacks, especially the largest sources in the Arctic.
Here are collected the AR5 references to Arctic feedbacks.
A 2012 UNEP report addressed the fact that the IPCC does not include permafrost carbon feedback, but the fact is the IPCC
AR5 2013-14 assessment omits all carbon feedbacks in its global warming projections.
The inevitable large degree of additional warming from these large slow feedbacks are totally excluded from the assessments because they are not included in the all important climate sensitivity. With the slow feedbacks the sensitivity is at least 6, but we still using a fast feedback only sensitivity of 3.
The IPCC 2007 AR4 included some carbon feedbacks but only as an uncertainty increasing the upper range of projected warming, that is not used for policy making (it should be). For a high emissions scenario (A2) this increased the IPCC AR4 projected warming by over 1.0C, and omitting this from the mitigation projections made for an error of 30%.
A 2013 review that included Earth system modelling found a large increase is climate sensitivity when carbon feedbacks are included, which would lead to at 50-100% increase in projected warming. "Traditionally, only fast feedbacks have been considered (with the other feedbacks either ignored or treated as forcing), which has led to estimates of the climate sensitivity for doubled CO2 concentrations of about 3C. The 2×CO2 Earth system sensitivity is higher than this, being∼4–6C if the ice sheet/vegetation albedo feedback is included in addition to the fast feedbacks, and higher still if climate–GHG feedbacks are also included."
July 2013 Review Climate sensitivity in the Anthropocene M. Previdi, et al
A 2013 study using the Canada climate model showed that zeroing CO2 emissions but not changing the other GHGs and adding in just a small permafrost carbon feedback results in atmospheric CO2 not stabilizing and global temperature slowly continuing to increase.
August 2013 Nature paper Climate Extremes and the Carbon Cycle finds extreme weather events compromise terrestrial carbon uptake, confirming that heat waves droughts and storms are a carbon feedback source. Terrestrial ecosystems absorb approximately 11 billion tons less carbon dioxide every year as the result of the extreme climate events than they could if the events did not occur. That is equivalent to approximately a third of global CO2 emissions per year.
Read more at: http://phys.org/news/2013-08-extreme-weather-events-fuel-climate.html#jCp
A 2012 published NASA study
has found tropical rainforests, that have been absorbing more CO2 under the rising atmospheric CO2, may be becoming less efficient as the rainforest temperature rises. This is predicted with increasing atmospheric CO2 as a strong carbon feedback
caused by global warming.
Terrestrial carbon feedback: Warming soil and vegetation
emit more CO2 as well as taking up more CO2 by photosynthesis
which a carbon feedback called the 'terrestrial' carbon feedback.
Its value projected by models by 2100 ranges from 0.5C to 1.5C.
These feedbacks are not generally classified as fast or slow,
coming some where in between. The higher range of 1.5C includes
Amazon die back and all research supports the prediction of Amazon
die back from increasing drying and severe drought.
Another deferred terrestrial carbon feedback is due to today's negative terrestrial carbon feedback. More atmospheric CO2 stimulates more photosynthesis forests and wood lands, which is acting as a large sink. The planet's land-based carbon "sink" has kept 186 billion to 192 billion tons of carbon out of the atmosphere since the mid-20th century, which is warmimg reduction of 0.3C (2012 Historical warming reduced due to enhanced land carbon uptake).
Some time this carbon sink will be saturated and switch to a carbon source. Most models (2012 research Terrestrial ecosystem carbon response ) say this will happen this century and about mid century.
The IPCC AR4 reported that above 3C from preindustrial the terrestrial carbon sink become a net source, which must be avoided at all costs.
Global wetlands emit more methane when warmed- not accounted for in the assessments.
Peatlands: Vast regions of high carbon peat rich wetlands (peatlands) are emitting more carbon as they are warmed - not accounted for. These are subArctic and tropical.
thawing permafrost is emitting carbon as methane and some CO2, and Arctic ocean floor frozen methane gas hydrate is melting and starting to emit methane into the atmosphere. These are the largest stores of carbon on the planet and are not accounted in assessments of future global climate change (UNEP Policy Implications of Warming Permafrost 2012
Arctic summer sea ice melting
is a visible dramatic effect of global warming and it's a large feedback. The vast expanse of white ice in the summer, cools the northern hemisphere and to an extent the planet as a whole. With its loss, the rate of global warming will increase. This is not included in the climate models. The models for projecting melting rate of the Arctic summer sea ice are in error by 30 years right now. (more on the Arctic below)Research predicts
that thawing permafrost (irreversible) will switch the Arctic from carbon sink to a net carbon source in the 2020s.
Climate-carbon cycle coupling is expected to add carbon dioxide
to the atmosphere as the climate system warms, but the magnitude of this
feedback is uncertain. (This
is the excluded carbon feedbacks)
"This increases the uncertainty in the trajectory of carbon
dioxide emissions required to achieve a particular stabilization level of
atmospheric carbon dioxide concentration. Based on current understanding of
climate-carbon cycle feedback, model studies suggest that to stabilize at 450
ppm carbon dioxide could require that cumulative emissions over the 21st century
be reduced from an average of approximately 670 [630 to 710] GtC (2460 [2310 to
2600] GtCO2) to approximately 490 [375 to 600] GtC (1800 [1370 to
excluding these inevitable carbon feedbacks the IPCC instead of considering risk
has included an error of 30% in its calculated emissions reduction for
Quotes are from IPCC 2007
The greatest risk from global warming to humanity and all life
is the multiple combined 'cascading' Arctic climate feed backs.
These are the following.
o Melting back of subarctic spring-summer snow cover.
o Melting decline of Arctic summer sea ice extent.
o Warming far north peat lands - emits methane.
o Thawing permafrost - emitting methane & nitrous oxide.
o Melting sea floor Arctic methane hydrate - methane.
Methane and nitrous oxide are much more powerful greenhouse gases than CO2.
The greatest single risk is an abrupt spreading destabilization of sub sea floor methane hydrates.
Positive feedback from warming may cause the
release of carbon or methane from the terrestrial biosphere and oceans (See Meehl et
al., 2007), which would add to the mitigation required.
Quote from IPCC AR4 2.2.4 Risk
of catastrophic or abrupt change.
The IPCC uses climate computer models projections of global
temperature increase to estimate the future degrees of warming.
Models used to date in the IPCC warming projections do not include
the amplifying carbon cycle feedbacks that the scientists now call
In the 2013 AR5 no (inevitable) extra carbon feedback warming was included in the new RCP scenario projections, and only the lowest terrestrial carbon feedback range was included in the AR5 carbon budget of more fossil fuels to burn. Consequently the AR5 global warming projection for business as usual isthe lowest since 1990. Unlike the AR4 the AR5 does not provide figure or formula for correcting the omitted terrestrial carbon feedback warming.
It is definite that carbon feedbacks will add to the warming over time.
The IPCC says "Warming tends to reduce land and ocean uptake of atmospheric carbon dioxide, increasing the fraction of anthropogenic emissions that remains in the atmosphere."
For the A2 scenario, for example, the IPCC says the climate-carbon cycle feedback increases the corresponding global average warming at 2100 by more than 1.0°C.
This does not include carbon feedback from peatland ,thawing permafrost or melting methane hydrate.
This additional 1.5C is not included in the 'most likely' temperature projections.
A 2012 carbon cycle paper, High sensitivity of future global warming
to land carbon cycle processes, finds the carbon feedback is large- at least 1.5C by 2100
Positive and negative feedback
There are two kinds of feedback in terms of amplifying warming (+ve) or reducing warming (-ve).
We are most used to negative feedback systems used for safety. If a heater gets to hot there is a built -ve feedback that switches it off.
But in the climate system there is no such safety mechanism- feedbacks act in the dangerously +ve feedback way.
In the case of global climate change positive feedbacks to global warming lead to more global warming. Global warming causes more global warming
Furthermore the increased warming accelerates over time and temperature.
Climate system +ve feedback is a global warming impact multiplier.
Considering all the feedbacks the +ve feedbacks are incomparably larger the -ve, and
the more the warming the larger the +ve feedbacks (but not the -ve).
Positive feedbacks that operate by the planet emitting more carbon dioxide (CO2) or methane (CH4) are +ve carbon (cycle) feedbacks.
By definition positive carbon feedback is the greatest risk caused by global warming - because our industrial global warming responds by emitting carbon GHGs CO2 and methane and that boosts global warming more that increases carbon feed back even more etc... - in the ultimate vicious cycle.
There are a great many of the +ve feedbacks and Earth has vast pools (stores) of carbon vulnerable to global warming- the largest being Arctic.
The warming planet emits CO2 methane and nitrous oxide- thawing permafrost is doing all this now.
Climate system positive feedbacks or loops tend to be self perpetuating and accelerating making them catastrophically dangerous.
One positive feedback may increase one or more other positive feedbacks - 'cascading' feedbacks, which leads to runaway rapid warming.
The big example is the Arctic involving Arctic methane.
There are unforeseen positive feedbacks
The melting of glaciers forms deep channels of water torrents and lake at
the glacier base lubricating its retreat.
Fast and Slow feedbacks
There are 2 sorts of feedbacks in terms of their speed of response.
Fast feedbacks (or Charney feedbacks) are the only ones accounted for
by the IPPC in global warming projections are the fast feedbacks.
These act on an immediate time scale and are water vapor, clouds
(+ve & -ve) aerosols (+ve and -ve). latest research confirms the strong
water vapor feedback and that clouds have a net positive (bad) feedback
Water vapor is a GHG and the largest +ve feedback.
It about doubles the warming caused by a GHG alone.
Warm air holds more water as global warming increases so amplifying
the global warming by a factor of 2 for warming by GHG alone.
It is a fast feedback
Slow feedbacks are much slower to respond to warming, but as they do
they are very large and can lead to catastrophic accelerating degrees of
They are the albedo cooling loss from the loss of ice sheets, warming wetland
peat (high carbon), thawing permafrost (CO2 CH4 N2O) and sub sea floor methane.
These large slow feedback are excluded by the IPCC global warming projections
in the assessments. They are also not included in the calculation of the all
important climate sensitivity.
9 July 2018 Wetlands and permafrost feedback adds 20% to atmospheric CO2 by 2100, and most important for 1.5C limit.
28 May 2018 Surfactant Invisible barrier on ocean surface (increases with warming) can reduce carbon uptake
4 May 2018 methane Greenhouse gas 'feedback loop' discovered in freshwater lakes
21 March 2018 Drought-induced changes in forest composition (USA) amplify effects of climate change
20 March 2018 Thawing permafrost produces more methane than expected Paper: Methane production as key to the greenhouse gas budget of thawing permafrost (much more methane)
11 March 2018Methane Feedbacks to the Global Climate System
in a Warmer World
23 Feb 2018 *Soil microbes' contribution to the carbon cycle in a warming world-enormous
Dec 2016 NOAA Arctic Report CardArctic switched from carbon sink to Source
5 Dec 2017Amazon floodplain trees emit as much methane as all Earth’s oceans combined
17 Nov 2017 Plant respiration- a bigger feedback on climate than expected
30 Oct 2017 C. Koven Higher climatological temperature sensitivity of soil carbon in cold than warm climates. ...strong carbon–climate feedbacks from northern soils
5 Oct 2017 Carbon feedback from forest soils will accelerate global warming, study finds
Sept 2017 Woods Hole Tropical forests are a net carbon source
Paper Tropical forests are a net carbon source now based on aboveground measurements of gain and loss.
April 2017Amazon 21st century drought-related fires -carbon emissions
8 May 2017Carbon dioxide sources from Alaska driven by increasing early winter respiration from Arctic tundra
Feb 2017 Greenhouse gas emissions from tropical
forest degradation: an underestimated source
Timothy R. H. Pearson
Feb 2017 B. Parker Radiative Forcing, Climate Sensitivity, and Global Warming.
'The combination (of all drivers)) is probably sufficient to lead to "runaway global warming" (8-10°C, not like Venus) as the additional warming causes additional greenhouse gases to be released in the Arctic region in a feedback loop.
20 Feb 2017 Warming ponds accelerate climate change (methane Carbon switch)
ARCTIC SWITCHED CARBON SINK TO SOURCE NOAA 2016 Arctic Report Card
Dec 2016 [Projects W. US megadrought C source]
Reduction in carbon uptake during turn of the
century drought in western North America
Christopher R. Schwalm
1 Dec 2016 Soil carbon
For 1C warming soil
carbon emissions =
2X human emissions
Nov 2016 COP22 Oceans
Coastal blue carbon
20 April 2016 ..permafrost
disturbance changed the
high Arctic tundra system
from a sink to a source
for CO2 during the majority
of the growing season
20 Mar 2016 Changing
temperature response of
respiration turns boreal
forest from carbon sink
into carbon source
Mar 2016 Carbon sink to
source possible by 2030
Drivers and patterns of
land biosphere carbon
19 Mar 2016 Nature
The terrestrial biosphere
as a net source of
greenhouse gases to the
22 Feb 2016 Study shows
Arctic ecosystem shifting
from carbon sink to carbon
Jan 2016 MIT Annual carbon
sequestration rate in
protected areas such
as rainforests will decline
by about 40 percent
between now and 2100.
14 Oct 2015 Bubble plumes
off Washington, Oregon
suggest warmer ocean
may be releasing frozen
Nov 2015 Royal Society
special edition Feedbacks
on climate in the Earth system’
Feedbacks, climate sensitivity and the limits of linear models
...to estimate the permafrost carbon–climate feedback
Sept 2015 Forest carbon source New estimates of CO2forest emissions and removals: 1990–2015
31 Aug 2015 Boreal:
Northern forests face onslaught from heat and drought- as well as other world forests
14 July 2015 Global wildfires on the rise
7 July 2015 warming mosses emit nitrous oxide
June 2015 Woods Hole Inst. Permafrost & climate change catastrophic runaway potential
June 2015 Global warming: Growing feedback from ocean carbon to climate
pdf full paper
March 2015 Direct evidence for a positive feedback in climate change: Global warming itself will likely accelerate warming
23 April 2015 Warming climate may release vast amounts of carbon from long-frozen Arctic soils
23 April 2015 New Study Finds Clouds are Amplifying Human Warming
15 April 2015 Increased atmospheric CO2 limits soil storage
23 April 2015 Thawing permafrost feeds climate change
Expert survey Permafrost zone carbon balance from 2013
20 April 2015 Study reveals 'two faces' of phytoplankton, +20% Arctic feedback
20 April 2015 Future productivity and carbon storage limited by terrestrial nutrient availability- carbon source by 2100
7 April 2015 Permafrost thawing-accelerate global warming
6 April 2015 Permafrost thawing in organic Arctic soils accelerated by ground heat production
3 April 2015 Climate change, plant roots may accelerate carbon loss from soils
30 March 2015 How Long Can Oceans Continue
To Absorb Earth’s Excess Heat?- heat sink may be starting to fail.
18 Mar 2017 Long-term decline of the Amazon carbon sink
18 Mar 2015 Computer sims: In climatic tug of war, carbon released from thawing permafrost wins handily
15 Mar 2015 Global methane and nitrous oxide emissions from terrestrial ecosystems due to multiple environmental changes Hanqin Tian,
30 March 2015 Direct evidence for a positive feedback in climate change (natural warming out of ice ages). Global warming will lead to more warming.
March 2015 J. Randerson prestn Climate-carbon feedbacks to 2100 and beyond.
March 2015 Amazon rainforest ability to soak up CO2 is falling
March 2015 C. Doughty Drought impact on forest carbon - in Amazonia uptake reduced
26 Feb 2015 Positive feedback of elevated CO2 on soil respiration in late autumn and winter
Jan 2015 - peatlands New research outlines global threat of smoldering peat fires
Jan 2015 Peatland carbon accumulation over millennia (huge slow)
Dec 2014 Huge soil carbon feedback-B. Sulman Microbe driven turnover ...
Sept 2014 Sunlight key to permafrost CO2 emissions
2014 Current systematic carbon-cycle observations & need for implementing ...carbon observing system P. Ciais
Sept 2014 K Karhu
Carbon stored in world's soils more vulnerable to climate change than expected- esp Boreal Arctic.
Aug 2014 Wide spread methane leakage (from hydrate) from ocean floor off US coast
April 2014 Carbon loss from soil Univ. Arizona accelerating climate change.
July 2014 The declining uptake rate of CO2 by land and ocean sinks.
M. R. Raupach
April 2014 wetlands responsible for new atmospheric methane increase
April 2014 Study finds accelerated soil carbon loss, increasing the rate of climate change
Mar 2014 G. Yvon-Durocher Methane fluxes Global warming to have a large impact on emissions from freshwater ecosystems increasing methane & CO2.
C. Lavergne Mar 2014 Cessation of deep convection in the open Southern Ocean under climate change. This has a feedback effect
R. Bernardello Mar 2014 Response of the Ocean Natural Carbon Storage to Projected Climate Change 'With climate change we predict that the ocean will lose some of its deep, natural carbon in the future'
Feb 2014 Amazon projected to become net carbon source Nature Drought sensitivity of Amazonian carbon balance
Jan 2014 Tropical ecosystem +ve carbon feedback. Over the past 50 years tropical ecosystems have become 2X as sensitive to climate with a declining capacity to store carbon.
2013 Trends and drivers of regional sources
and sinks of carbon dioxide over the past
Dec 2013 Boreal forests threaten to produce climate-warming gases
30 Oct 2013 Warming will disturb balance of soil nutrients in drylands, make drylands less productive, and act as +ve carbon feedback
Aug 2013 First signs of carbon sink saturation in European forest biomass
Feb 2013 Wetland trees a significant overlooked source of methane
2012 ..terrestrial ecosystem carbon response to CMIP5 climate change projections
gain big +ve feedback
Sept 2013 Plankton
The science of global climate change is all about feedbacks -
these mostly positive (bad) amplifying feedbacks. As global
warming increases so do the +ve feedbacks. What negative there are have little effect.
Global warming inherently increases global warming.
The biggest feedbacks were predicted long ago, but are kicking much sooner than expected.
It is the biggest reason why we are in a state of dire planetary emergency.
The 2014 IPCC AR5 assessment finds that the carbon cycle will be a +ve
(amplifying) feedback this century. The highest estimate of extra carbon
feedback warming in the AR5 is 1.8C by 2100 (B. Booth). How ever,
'many key processes relevant to decomposition of carbon are missing in
models (Todd-Brown et al., 2012), and particularly for permafrost carbon
and for carbon in boreal and tropical wetlands and peatlands, despite the large
amount of carbon stored in these ecosystems and their vulnerability to
warming'. (IPCC AR5 WG2 ch 6 p 40).
Also 'the negative effects of elevated tropospheric ozone on NPP (plant growth) have not been taken into account by most current carbon cycle models'. 'Plants are known to suffer damage due to exposure to levels of ozone (O3) above about 40 ppb (Ashmore, 2005). Model simulations of plant O3 damage on the carbon cycle have found a reduction in terrestrial carbon storage 2005 - 2100 up to 260 PgC (Sitch et al., 2007) AR5 Ch 6.
Today most of the largest sources of catastrophically dangerous feedbacks are operant or triggered, and today we are committed to a far greater degree of global warming - that will cause far greater feedbacks accelerating the rate of warming. Note the rate of warming is critical to ecosystems, species, and agriculture.
It is shocking therefore that the IPCC omits the inevitable large increase in global warming due to the largest +ve feedbacks and in the 2013 AR5 omitted all carbon cycle warming from its RCP scenario global warming projections.
The largest source of amplifying carbon feedback by far is subsea floor frozen sold pressurized methane gas -hydrate. The methane hydrate situation is far worse than
we ever imagined.
CLIMATE EMERGENCY INSTITUTE
The health and human rights approach to climate change
2015 Planetary amplifying feedback confirmed The big (Mar 2015) climate change feedback news is that the strong +ve amplifying natural GHG feedback (CO2-methane-nitrous oxide) that ends ice changes by switching to an interglacial warm period, is confirmed by research (article global warming does increase warming). University of Exeter. "Direct evidence for a positive feedback in climate change: Global warming itself will likely accelerate warming." ScienceDaily.
The most dangerous of all feedbacks to the planet is methane from melting sub-sea floor frozen solid methane gas hydrates, and from Oct 2015 research it looks like it has started, as also previously suggested by Arctic research.
2014 NAS Royal Society 'Models vary in their projections of how much additional warming to expect, but all such models agree that the overall net effect of feedbacks is to amplify the CO2-only warming by a factor of 1.5 to 4.5'.
23 April 2015 research ARCTIC MULTI-FEEDBACK RUNAWAY EFFECT
The more we research the more we find that many large +ve amplifying
feedbacks will greatly accelerate global climate change, and are already trigerred.
Definition The NOAA says a positive feedback is a process in which an initial change
will bring about an additional change in the same direction. A feedback loop then
does not have to be complete to the point of an global warming increase.
A feedback exists if the process is established whereby warming will be made to increase.
The best example of a climate change amplifying feedback due to global warming (already happening) is increased forest fires that emit CO2.
The present biggest feedback is a fast acting one due to water vapour, which is a GHG. Warmer air holds more water vapor hence a +ve feedback. The water vapor feedback doubles the warming caused by a GHG alone. 2014 research
determined that this will act as an increasing climate change amplifier.
The 2014 IPCC AR5 found that 'Based on Earth System Models, there is high confidence that the feedback between climate change and the carbon cycle will amplify global warming', but the AR5 published model projections of warming did not account for any of the large planetary sources of amplifying carbon feedbacks.
Carbon feedback sources carry on emitting so long as the warming that triggered them lasts, & the higher the warming the greater the feedback - projected to make global warming last over 10,000 years (2013 R. Zeebe).
July 2012 Arctic warming linked to combination of reduced sea ice (feedback) and global atmospheric warming (global warming)
PPt. Biospheric Feedback Loops & Rapid Climate Change J.Cairns 2010
Carbon sink to carbon source. Today it is estimated that half of our extra GHG emissions are being taken up by more forest growth (terrestrial carbon sink) and the oceans (ocean carbon sink.
This is a negative feedback to CO2 pollution. We know that in time this increase in carbon uptake will be come less efficient and it will switch from being a carbon sink to a carbon source,+ve feedback to global warming.
Mar 2016 This has started-The terrestrial biosphere as a net source of greenhouse gases to the atmosphere.
Jan 2016 MIT Annual carbon sequestration rate in protected areas such as rainforests will decline by about 40 percent between now and 2100.
December 2016 Massive amounts of carbon dioxide could leak from the soil by mid-century
March 2016 Land flux emissions of methane & nitrous oxide exert double the cooling effect of CO2 land (green vegetation) uptake.
Mar 2015We have CO2, methane and nitrous oxide feedback emissions
Carbon sink will switch to source IPCC TAR
July 2012 Reduction in carbon uptake during turn of the century drought in western North America C. Schwalm [Projected to increase].
We show that the area-integrated strength of the western North American carbon sink declined by 30–298 Tg C yr−1 during the 2000–2004 drought. We further document a pronounced drying of the terrestrial biosphere during this period, together with a reduction in river discharge and a loss of cropland productivity. We compare our findings with previous palaeoclimate reconstructions and show that the last drought of this magnitude occurred more than 800 years ago. Based on projected changes in precipitation and drought severity, we estimate that the present mid-latitude carbon sink of 177–623 Tg C yr−1 in western North America could disappear by the end of the century
*We are releasing about 10 billion metric tons of carbon into the atmosphere per year. The world's soils contain about 3,500 billion metric tons of carbon. If soil carbon is added to the atmosphere due to microbial activity in warmer soils, that will accelerate the global warming process. And once this self-reinforcing feedback begins, there is no way to turn it off. | <urn:uuid:20c19454-75ac-4f36-bfc4-023635d42cad> | 2.78125 | 5,743 | Knowledge Article | Science & Tech. | 42.783705 | 95,515,160 |
Problem statement: Peat has been identified as one of the major groups of soils found in Malaysia. Sarawak as the largest state in Malaysia has the biggest reserve of peat-land. There are about 1.5 million ha of peat-land in Sarawak, which are relatively under developed. As is the case with any plant, oil palm trees do sequester carbon as they grow. Nevertheless, the process of clearing forest in order to establish a plantation may release carbon. Little studies have been done on the comparison of soil organic matter, soil organic carbon and yield of humic acids when secondary forest on peat soil is converted to oil palm plantation. The objective of this study was to compare carbon storage of secondary forest and early stages of oil palm plantations on a tropical peat soil. Approach: Soil samples were collected from the secondary forest, 1, 3, 4 and 5 year old oil palm plantations in Tatau district, Sarawak. Ten samples were taken at random with a peat auger at 0-25 and 25-50 cm depths. The bulk densities at these depths were determined by the coring method. The bulk density method was used to quantify the total carbon, total organic matter, total nitrogen, humic acids and stable carbon at the stated sampling depths on per hectare basis. Results: There were no significant differences in the amounts of stable C of both secondary forest and different ages of the oil palm plantations at 0-25 and 25-50 cm soil depth. The amounts of stable C in the secondary forest, 1, 3, 4 and 5 year old oil palm plantations at 0-25 cm depth were generally higher than those in the 25-50 cm depth. This was attributed to higher yield of HA in the secondary forest, 1, 3, 4 and 5 year old oil palm plantations soil partly due to better humification at the 0-25 cm soil depth.Conclusion: Conversion of secondary forest on peat to initial stages of oil palm plantation seems to not exert any significant difference on carbon storage in tropical peat soil.
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What does Jack LaLanne have in common with a Jamaican lizard?
Like the ageless fitness guru, the lizards greet each new day with vigorous push-ups. That's according to a new study showing that male Anolis lizards engage in impressive displays of reptilian strength -- push-ups, head bobs, and threatening extension of a colorful neck flap called a dewlap -- to defend their territory at dawn and dusk.
The lizards are the first animals known to mark dawn and dusk through visual displays, rather than the much better known chirping, tweeting, and other sounding off by birds, frogs, geckos, and primates.
Terry J. Ord, a postdoctoral researcher at Harvard University's Museum of Comparative Zoology and at the University of California, Davis, describes the Anolis lizards' unusual morning ritual in a forthcoming issue of the journal American Naturalist.
"Anoles are highly visual species, so in that sense it's not surprising that they would use visual displays to mark territory," Ord says. "Still, the finding is surprising because these are the first animals known to use non-acoustic signaling at dawn and dusk."
Ord studied four species of Jamaican forest lizard: Anolis lineatopus, Anolis sagrei, Anolis grahami, and Anolis opalinus. Female anoles establish small territories allowing access to food and other resources, while males stake out larger territories allowing them access to several females. The males spend much of the day sitting on tree trunks and displaying head motions, push-ups, and dewlap extensions, all to warn other males away from their territory.
Ord carefully located and videotaped individual males at different times of day, from before dawn to dusk. In all four species, he found distinct peaks of activity at daybreak and for about two hours afterward, and again just before dark.
"These patterns have remarkable parallels with the dawn and dusk choruses reported for many acoustically communicating animals," Ord says.
As in many species of birds, anoles leave their daytime perches at night to find safe shelter, since both birds and reptiles are frequently targeted by nocturnal predators.
"The dawn chorus may be a way of communicating having survived the night," Ord says. "If in the morning a bird doesn't hear its neighbor, or an anole doesn't see its neighbor, it may be an opportunity for the animal to expand its territory."
While ornithologists disagree on the exact reasons why birds chorus at dawn and dusk -- competing hypotheses propose everything from territorial defense to favorable environmental conditions to manifestations of circadian rhythms -- Ord says his work suggests male anoles use their morning displays primarily to mark territory.
"All of these behaviors are displays of physical vigor," Ord says. "As in humans, if an anole can do many of these push-ups it shows that he is in prime physical condition. These displays of strength help avert actual physical confrontations between male lizards, which can be very fierce and destructive."
Ord's work may open the doors to further study by ornithologists, herpetologists, and others seeking evidence of non-acoustic dawn and dusk signaling among other species.
Steve Bradt | EurekAlert!
O2 stable hydrogenases for applications
23.07.2018 | Max-Planck-Institut für Chemische Energiekonversion
Scientists uncover the role of a protein in production & survival of myelin-forming cells
19.07.2018 | Advanced Science Research Center, GC/CUNY
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
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Demonstrations 1 - 20 of 171
Reaction Rate Dependence on Temperature and Moisture During Storage
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Single-Step Reaction Kinetics Using Collision Theory
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Polymerization in a Batch Reactor
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Construct a Conversion-Temperature Diagram for a Reversible Adiabatic Reaction
Reactor Rate and Conversion versus Space Velocity
Radial and Axial Variations in a Nonisothermal Tubular Reactor
Michaelis-Menten Enzyme Kinetics of Bi-Bi Reactions
Kinetic and Thermodynamic Control of Electrophilic Addition Reactions
Successive Three-Point Method for Weibullian Chemical Degradation
Marcus Theory of Electron-Transfer Reactions
Parallel Nonisothermal Reactions in Batch and Semibatch Reactors
Water Contact Angle for Heterogeneous Surface
Reversible Reaction in an Adiabatic Plug-Flow Reactor
Why Density Change Cannot Be Ignored in a Plug Flow Reactor (PFR)
Chemical Equilibrium in the Haber Process
Effect of Tube Diameter on Plug Flow Reactor
Inhibition of Enzyme Reactions in Continuous Stirred-Tank Reactor and Batch Reactor
Langmuir Isotherms for a Binary Mixture
Multiple Steady States in a Continuous Stirred-Tank Reactor with Heat Exchange
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Hole discovered in Earth's magnetic field that protects planet from sun's rays
A large hole has been observed in the magnetic field that protects Earth from the sun's violent blasts, researchers have revealed.
The discovery was made last summer by Themis, a fleet of five small NASA satellites.
The Earth's magnetic field protects the planet from severe space weather but satellite observations have found it can develop two cracks from time to time.
This allows solar wind - a stream of charged particles spewing from the sun at 1 million mph - to penetrate the Earth's upper atmosphere.
The Earth's magnetic field acts like a bubble that protects the planet from solar activity
Such a breach can cause brilliant auroras or disrupt satellite and ground communications.
Last summer, Themis calculated a layer of solar particles to be at least 4,000 miles thick in the outermost part of the Earth's magnetosphere, the largest tear of the protective shield found so far.
'It was growing rather fast,' Themis scientist Marit Oieroset from the University of California said.
Such breaches are temporary, and the one observed last year lasted about an hour, Professor Oieroset said.
A breach in the Earth's magnetic field can cause brilliant auroras like this one in Norway and disrupt satellite communications
Solar flares are a potential danger to astronauts in orbit but generally are not a risk to people on the surface of the Earth.
The research was funded by NASA and the National Science Foundation.
Scientists initially believed the greatest solar breach occurred when the Earth's and sun's magnetic fields are pointed in opposite directions. But data from Themis found the opposite to be true.
Twenty times more solar wind passed into the Earth's protective shield when the magnetic fields were aligned, Professor Oieroset said.
A massive solar eruption in 2002. The Earth's magnetic field protects the planet from most of the solar flares
The Themis results could have a bearing on how scientists predict the severity of solar storms and their effects on power grids, airline and military communications and satellite signals.
The Themis satellites were launched to find the source of brief powerful geomagnetic disturbances in the Earth's atmosphere.
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So I've been reading and hearing (via lectures and podcasts) about Neuroengineering recently, and I've been super excited about the possibilities it holds for the next major stage of human development. I'm sure most people have heard of Cochlear Implants which, unlike regular hearing aids, do not simply amplify sound but are directly and surgically implanted into the head of a deaf person to electrically stimulate auditory nerves.
And while bulky and perhaps cosmetically cumbersome, these represent a step in a direction that is really exciting. As our surgical skill and knowledge of anatomy has exponentially increased scientists have made clear that it is possible to literally alter the electromechanics in our brains for a more favorable result. Another such technology is Retinal Implantation. Groups like The Boston Retinal Implant Project are working on a device thinner than the breadth of a hair and equipped with a tiny micro chip that controls small electrical impulses to the retina.
In the two most common types of blindness, retinitis pigmentosa, and age-related macular degeneration, many nerve endings that are in charge of sending visual stimulus to the brain are left in tact, it is these nerves that retinal implants use to simulate natural vision. Again, surgically altering the anatomy to function normally.
Research being conducted by a variety of groups is beginning to successfully control other types of brain function using Neuroengineering techniques. In one such case a group at Standford University led by Dr. Karl Deisseroth created a device that could electronically and wirelessly control the actions of a mouse by stimulating a part of the brain used for motor function. In this video we see the white implant protruding from the mouse's head. When the light is activated his brain is being told to run left. Notice the near perfect left-hand circle the mouse runs for the duration of the lights illumination.
Here again we see the amazing direct control and manipulation of the brain by way of external mechanics. With such technologies it is easy to ask what other parts of the brain could be stimulated or suppressed? Is there a way to surgically alter parts of the brain that control happiness, sadness, or fear? Is it possible to have a similar remote control for our emotions? If all our brain's functions are the process of electrical connections, could we not control every aspect of our brains as we saw fit...technologically overpowering all shortcomings in our brains?
Perhaps we're not there yet, but there are certainly some interesting technologies that indicate the immense potential we have. Transcranial magnetic stimulation or TMS, while not a surgical implantation, is one such technology. Originally used to measure patients' brain function in cranial surgery, TMS has been used recently in some very interesting ways. Researcher Allan Snyder, who works at the Centre for the Mind, who has done a considerable amount of work with autistic savants, is using this shower cap like device to see how it may affect a normal brain. Surprisingly, it may have savant like results. In his few studies he has found "40 percent of the people he exposed to TMS pulses displayed artistic and quantitative abilities that didn't seem to have been present before." Though the affects of the TMS wear off after a short period it opens a broad question of how our brains work, and what potentials we have within us.
As technologies improve, and with them our understanding of our brains, our ability to effectively intervene with failing systems
( ie. brains affected by parkinsons disease, or other degenerative disease) becomes an exciting possibility.
Here Juan Enriquez discusses what such technologies as those used in Neuroengineering could have on our evolution as human beings.
My sources for this little investigation include:
Stuff You Should Know Podcast
How Stuff Works
A two part article on Neuroengineering
37 minutes ago | <urn:uuid:ea860816-2d5f-49af-9371-0ec33fc59737> | 3.21875 | 781 | Personal Blog | Science & Tech. | 34.86051 | 95,515,258 |
Reverse string using pointers and function
Write a C Program to reverse string using pointers and function. Here’s simple Program to reverse string using pointers and function in C Programming Language.
What are Pointers?
A pointer is a variable whose value is the address of another variable, i.e., direct address of the memory location. Like any variable or constant, you must declare a pointer before using it to store any variable address.
The general form of a pointer variable declaration is −
Here, type is the pointer’s base type; it must be a valid C data type and var-name is the name of the pointer variable.
The asterisk * used to declare a pointer is the same asterisk used for multiplication. However, in this statement the asterisk is being used to designate a variable as a pointer.
The unary or monadic operator & gives the “address of a variable'”.
The indirection or dereference operator * gives the “contents of an object pointed to by a pointer”.
Below is the source code for Program to reverse string using pointers and function which is successfully compiled and run on Windows System to produce desired output as shown below :
SOURCE CODE : :
/* C Program to reverse string using pointers and function */
printf("Enter any String :: ");
printf("\nThe Reverse of the String [ %s ] is :: ");
Output : :
/* C Program to reverse string using pointer and function */
Enter any String :: CodezClub
The Reverse of the String [ CodezClub ] is :: bulCzedoC
Process returned 0
Above is the source code for C Program to reverse string using pointers and function which is successfully compiled and run on Windows System.The Output of the program is shown above .
If you found any error or any queries related to the above program or any questions or reviews , you wanna to ask from us ,you may Contact Us through our contact Page or you can also comment below in the comment section.We will try our best to reach up to you in short interval.
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An intermediate-mass black hole (IMBH) is a class of black hole with mass in the range 102-105 solar masses: significantly more than stellar black holes but less than the 105-109 solar mass supermassive black holes. There is as yet no unambiguous detection of an IMBH, but the indirect evidence from various directions is promising.
The strongest evidence for IMBHs comes from a few low-luminosity active galactic nuclei. Due to their activity, these galaxies almost certainly contain accreting black holes, and in some case the black hole masses can be estimated using the technique of reverberation mapping. For instance, the spiral galaxy NGC 4395 at a distance of about 4 Mpc appears to contain a black hole with mass of about 3.6×105 solar masses.
Some ultra-luminous X ray sources (ULXs) in nearby galaxies are suspected to be IMBHs, with masses of a hundred to a thousand solar masses. The ULXs are observed in star-forming regions (e.g., in starburst galaxy M82), and are seemingly associated with young star clusters which are also observed in these regions. However, only a dynamical mass measurement from the analysis of the optical spectrum of the companion star can unveil the presence of an IMBH as the compact accretor of the ULX.
A few globular clusters have been claimed to contain IMBHs, based on measurements of the velocities of stars near their centers; the figure shows one candidate object. However none of the claimed detections has stood up to scrutiny. For instance, the data for M31 G1, the object shown in the figure, can be fit equally well without a massive central object.
Finally, the M-sigma relation predicts the existence of black holes with masses of 104 to 106 solar masses in low-luminosity galaxies. There are three main types of black hole: stellar, intermediate, and supermassive.
In November 2004 a team of astronomers reported the discovery of GCIRS 13E, the first intermediate-mass black hole in our galaxy, orbiting three light-years from Sagittarius A*. This medium black hole of 1,300 solar masses is within a cluster of seven stars, possibly the remnant of a massive star cluster that has been stripped down by the Galactic Center. This observation may add support to the idea that supermassive black holes grow by absorbing nearby smaller black holes and stars. However, in 2005, a German research group claimed that the presence of an IMBH near the galactic center is doubtful, based on a dynamical study of the star cluster in which the IMBH was said to reside. An IMBH near the galactic center could also be detected via its perturbations on stars orbiting around the supermassive black hole.
In January 2006 a team led by Philip Kaaret of the University of Iowa announced the discovery of a quasiperiodic oscillation from an intermediate-mass black hole candidate located using NASA's Rossi X-ray Timing Explorer. The candidate, M82 X-1, is orbited by a red giant star that is shedding its atmosphere into the black hole. Neither the existence of the oscillation nor its interpretation as the orbital period of the system are fully accepted by the rest of the scientific community. While the interpretation is quite reasonable, the periodicity claimed is based on only about 4 cycles, meaning that it is quite possible for this to be random variation. If the period is real, it could be either the orbital period, as suggested, or a super-orbital period in the accretion disk, as is seen in many other systems.
In 2009, a team of astronomers led by Sean Farrell discovered HLX-1, an intermediate-mass black hole with a smaller cluster of stars around it, in the galaxy ESO 243-49. This evidence suggested that ESO 243-49 had a galactic collision with HLX-1's galaxy and absorbed the majority of the smaller galaxy's matter.
In 2015 a team at Keio University in Japan found a gas cloud (CO-0.40-0.22) with very wide velocity dispersion. They performed simulations and concluded that a model with a black hole of circa 100,000 solar masses would be the best fit for the velocity distribution. However, a later work pointed out some difficulties with the association of high velocity dispersion clouds with intermediate mass black holes, and proposed that such clouds might be generated by supernovae. Radio observations with the Atacama Large Millimeter/submillimeter Array confirmed absence of an IMBH near CO-0.40-0.22, and found that the large velocity dispersion of the cloud is created by superposition of two molecular clouds with different line-of-sight velocities.
In 2017, it was announced that a black hole of a few thousand solar masses may be located in the globular cluster 47 Tucanae. This was based on the accelerations and distributions of pulsars in the cluster, however later analysis of an updated and more complete data set on these pulsars finds no positive evidence for this.
Intermediate-mass black holes are too massive to be formed by the collapse of a single star, which is how stellar black holes are thought to form. Their environments lack the extreme conditions—i.e., high density and velocities observed at the centers of galaxies—which seemingly lead to the formation of supermassive black holes. There are three postulated formation scenarios for IMBHs. The first is the merging of stellar mass black holes and other compact objects by means of accretion. The second one is the runaway collision of massive stars in dense stellar clusters and the collapse of the collision product into an IMBH. The third is that they are primordial black holes formed in the Big Bang. | <urn:uuid:4cc3ca96-1a34-4b48-8200-355ce7b910af> | 3.59375 | 1,203 | Knowledge Article | Science & Tech. | 44.532695 | 95,515,262 |
Every 25.34 days, the object, designated LRLL 54361, unleashes a burst of light. Although a similar phenomenon has been observed in two other young stellar objects, this is the most powerful such beacon seen to date.
Credit: NASA, ESA, J. Muzerolle (STScI), E. Furlan (NOAO and Caltech), K. Flaherty (Univ. of Arizona/Steward Observ.), Z. Balog (Max Planck Inst. for Astronomy), and R. Gutermuth (Univ. of Massachusetts, Amherst) Acknowledgment: R. Hurt (Caltech/Spitze
PROTOSTAR LRLL 54361 -- NASA's Spitzer and Hubble space telescopes have teamed up to uncover a mysterious infant star that behaves like a police strobe light. [Left] -- This is a false-color, infrared-light Spitzer image of LRLL 54361 inside the star-forming region IC 348 located 950 light-years away. The Spitzer Space Telescope discovered an unusual variable object that has the typical signature of a protostar. The object emits a burst of light every 25.34 days. [Center] -- This Hubble Space Telescope monochromatic-color image resolves the detailed structure around the protostar, consisting of two cavities that are traced by light scattered off their edges above and below a dusty disk. The cavities were likely blown out of the surrounding natal envelope of dust and gas by an outflow launched near the central object. [Right] -- This is an artist's impression of the hypothesized central object that may be two young binary stars. Astronomers propose that the flashes are due to material in a circumstellar disk suddenly being dumped onto the growing stars and unleashing a blast of radiation each time the stars get close to each other in their orbit.
The heart of the fireworks is hidden behind a dense disk and envelope of dust. Astronomers propose the light flashes are caused by periodic interactions between two newly formed stars that are binary, or gravitationally bound to each other. LRLL 54361 offers insights into the early stages of star formation when lots of gas and dust is being rapidly accreted, or pulled together, to form a new binary star.
Astronomers theorize the flashes are caused by material suddenly being dumped onto the growing stars, known as protostars. A blast of radiation is unleashed each time the stars get close to each other in their orbits. This phenomenon, called pulsed accretion, has been seen in later stages of star birth, but never in such a young system or with such intensity and regularity.
"This protostar has such large brightness variations with a precise period that is very difficult to explain," said James Muzerolle of the Space Telescope Science Institute in Baltimore, Md. His paper recently was published in the science journal Nature.
Discovered by NASA's Spitzer Space Telescope, LRLL 54361 is a variable object inside the star-forming region IC 348, located 950 light-years from Earth. Data from Spitzer revealed the presence of protostars. Based on statistical analysis, the two stars are estimated to be no more than a few hundred thousand years old.
The Spitzer infrared data, collected repeatedly during a period of seven years, showed unusual outbursts in the brightness of the suspected binary protostar. Surprisingly, the outbursts recurred every 25.34 days, which is a very rare phenomenon.
Astronomers used NASA's Hubble Space Telescope to confirm the Spitzer observations and reveal the detailed stellar structure around LRLL 54361. Hubble observed two cavities above and below a dusty disk. The cavities are visible by tracing light scattered off their edges. They likely were blown out of the surrounding natal envelope of dust and gas by an outflow launched near the central stars. The disk and the envelope prevent the suspected binary star pair from being observed directly. By capturing multiple images over the course of one pulse event, the Hubble observations uncovered a spectacular movement of light away from the center of the system, an optical illusion known as a light echo.
Muzerolle and his team hypothesized the pair of stars in the center of the dust cloud move around each other in a very eccentric orbit. As the stars approach each other, dust and gas are dragged from the inner edge of a surrounding disk. The material ultimately crashes onto one or both stars, which triggers a flash of light that illuminates the circumstellar dust. The system is rare because close binaries account for only a few percent of our galaxy's stellar population. This is likely a brief, transitory phase in the birth of a star system. "Assuming the pulsed accretion hypothesis is correct, the disk is circumbinary, which means it encircles both stars. There may be small circumstellar disks around each star, though that is perhaps less likely given the strong pulse signature," said Muzerolle.
Muzerolle's team next plans to continue monitoring LRLL 54361 using other facilities including the European Space Agency's Herschel Space Telescope. The team hopes to eventually obtain more direct measurements of the binary star and its orbit.For related images and video, visit:
NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington, D.C. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena.
Ray Villard | Newswise
What happens when we heat the atomic lattice of a magnet all of a sudden?
18.07.2018 | Forschungsverbund Berlin
Subaru Telescope helps pinpoint origin of ultra-high energy neutrino
16.07.2018 | National Institutes of Natural Sciences
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
19.07.2018 | Materials Sciences
19.07.2018 | Earth Sciences
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On Aug. 21, a total solar eclipse will sweep across the U.S., starting in Oregon and ending in South Carolina. It’s been nearly a century since a total solar eclipse touched both U.S. coasts.
So how predictable are events like the Great American Eclipse? Phillip Nicholson, an astronomy professor at Cornell University who studies the solar system, says they’re very predictable – you can actually calculate future eclipse times within a few seconds. But millions of years from now, total solar eclipses will only be a thing of the past.
“While apparently random, solar and lunar eclipses in fact occur following a fairly complex pattern of cycles, in which the main 18-year period is known as the Saros cycle. The ancients knew of this cycle and used it to make predictions, but we understand now that this cycle simply reflects the orbital motion of the Moon about the Earth every 29.53 days combined with the Earth’s motion about the sun every 365.35 days. After 18 years and 11 days, the pattern of New Moons and eclipses repeats itself almost exactly.
“We can predict future eclipse times within a few seconds for several centuries into the future, and the eclipse tracks within a few tens of kilometers. The limitation on our accuracy is set by the slightly irregular spin of the Earth on its axis, which changes exactly where the path of totality will fall on Earth. In fact, one reason we know the Earth’s spin is irregular is by studying records of ancient eclipses and where they were seen.
“In the distant future, which is several millions of years from now, there will be no more total solar eclipses because the Moon will have moved too far away from the Earth to cover the sun’s disk completely. We live in a lucky time!” | <urn:uuid:997f6dc8-294e-430d-b48d-ec3ab72ce54f> | 3.65625 | 376 | News Article | Science & Tech. | 57.051 | 95,515,270 |
Two of the world’s leading astronomical institutions have formalized an agreement to cooperate on joint efforts for the technical and scientific advancement of radio astronomy.
Using the supersharp radio vision of the National Science Foundation’s Very Long Baseline Array, astronomers have made the most precise measurement ever of the distance to a famous star-forming region.
Astronomers studying archival data from an Australian radio telescope have discovered a powerful, short-lived burst of radio waves that they say indicates an entirely new type of astronomical phenomenon.
High school students and teachers will join astronomers on the cutting edge of science under a program to be operated by the National Radio Astronomy Observatory and West Virginia University, and funded by the National Science Foundation.
Astronomers have found an enormous hole in the Universe, nearly a billion light-years across, empty of both normal matter such as stars, galaxies, and gas, and the mysterious, unseen dark matter.
The first of two ALMA transporters — unique vehicles designed to move high-tech radio-telescope antennas in the harsh, high-altitude environment of the Atacama Large Millimeter/submillimeter Array — has been completed and passed its initial operational tests.
Astronomers using data from the National Science Foundation’s Robert C. Byrd Green Bank Telescope have found the largest negatively-charged molecule yet seen in space. The discovery of the third negatively-charged molecule, called an anion, in less than a year and the size of the latest anion will force a drastic revision of theoretical models of interstellar chemistry, the astronomers say. | <urn:uuid:433462fa-aa54-4f38-b609-5e0e0bb7a28b> | 3.34375 | 328 | Content Listing | Science & Tech. | 11.489496 | 95,515,277 |
I used to think that macros were just a feature that a language included or lacked. In practice, there’s a huge design space of how macro systems can be implemented.
Baby Steps to a C Compiler
Writing a compiler, and learning a little low-level programming, is a very powerful way of learning more about how computers work.
Recursion, TCO, and You
Recursion is an excellent tool in a developer’s toolbox, yet it is frequently misunderstood. Used correctly, it can give programs that are fast, readable and succinct. Used incorrectly, it can produce some tricky bugs.
Trifle: Lists and CONSequences
Lists are a spectacularly important data type. Even more so for lisp languages, as a lisp program is just a text file with some list literals. | <urn:uuid:169a25c6-e9e7-4646-a8d4-d10fe89bdb7e> | 2.78125 | 171 | Content Listing | Software Dev. | 45.849688 | 95,515,309 |
Since passage of the Endangered Species Act in 1973, over 1,300 endangered species have been protected in the United States and its territories. In the forthcoming issue of Ecology Letters, Male & Bean assess 14 years of endangered plant and animal status trends and show that the length of time species are protected, and the amount of money spent on their conservation are key variables in explaining trends.
Overall, about half of species protected are no longer declining and only 35 % of species protected for 13 years or more were still declining. Status trends are partly explained by taxonomy and funding. Species reported as receiving more money from the U.S. Fish and Wildlife Service or National Oceanic and Atmospheric Administration were much more likely to be improving or stable than those receiving less funding.
This study emphasizes the need to consider the ways in which agencies administer and the U.S. Congress funds the Endangered Species Act in judging whether the law is a success or failure in recovering biodiversity. This issue has become a major focus of political battles over this controversial environmental law.
Lynne Miller | EurekAlert!
Upcycling of PET Bottles: New Ideas for Resource Cycles in Germany
25.06.2018 | Fraunhofer-Institut für Betriebsfestigkeit und Systemzuverlässigkeit LBF
Dry landscapes can increase disease transmission
20.06.2018 | Forschungsverbund Berlin e.V.
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
20.07.2018 | Power and Electrical Engineering
20.07.2018 | Information Technology
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Global Carbon Dioxide Emissions to Reach 36 Billion Tonnes in 2013
News Nov 26, 2013
The report shows that global emissions due to fossil fuel alone are set to grow this year at a slightly lower pace of 2.1 per cent than the average 3.1 per cent since 2000, reaching 36 billion tonnes by the end of this year – 61 per cent above emissions in 1990. The 2013 growth comes on top of a similar 2.2 per cent increase in 2012 reinforcing a slower than average growth.
The Budget, produced by the Global Carbon Project, is an annual report of carbon dioxide emissions, land and ocean sinks and accumulation in the atmosphere, incorporating data from multiple research institutes from around the world.
This year’s report also shows that atmospheric carbon dioxide levels increased in 2012 at a faster rate than the average over the past 10 years because of a combination of continuing growth in emissions and a decrease in land carbon sinks from very high levels in the previous two years. Carbon dioxide uptake from the atmosphere to land in 2012 was lower than the very high levels in 2011 and 2010, returning to average levels of the last decade.
Growth rates for major emitter countries in 2012 were 5.9 per cent (China), −3.7 per cent (USA), −1.3 per cent (EU28), and 7.7 per cent (India). The 2012 carbon dioxide emissions breakdown is coal (43 per cent), oil (33 per cent), gas (18 per cent), cement (5.3 per cent) and gas flaring (0.6 per cent).
Cumulative emissions of carbon dioxide from all sources (fossil fuels plus land use change) since 1870 will reach 2,015 billion tonnes of carbon dioxide this year. A continuation of the emissions growth trends observed since 2000 would place the world on a path to reach 2 degrees Celsius above pre-industrial times in 30 years.
Dr House said: "About a third of carbon dioxide emissions stay in the atmosphere for centuries. A continuing rise in emissions will take us faster towards major impacts that will be felt within our own generation, and a greater burden for our children's generation. Reducing fossil fuel emissions through energy efficiency, renewable energy and through small individual changes is possible now, and will improve energy security now and in the longer term."
The new figures coincide with the global launch of the Global Carbon Atlas, an online platform to explore, visualise and interpret the emissions data at the global, regional and national scales.
How do Forests Respond to Atmospheric Pollution?News
How forests respond to elevated nitrogen levels from atmospheric pollution is not always the same. While a forest is filtering nitrogen as expected, a higher percentage than previously seen is leaving the system again as the potent greenhouse gas nitrous oxide, say researchers.READ MORE
Lake gives Clues to Earth's Ancient AtmosphereNews
A sample of ancient oxygen, teased out of a 1.4 billion-year-old evaporative lake deposit in Ontario, provides fresh evidence of what the Earth’s atmosphere and biosphere were like during the interval leading up to the emergence of animal life.READ MORE | <urn:uuid:937be8b0-f8be-4e51-9923-f06b88ee97a6> | 3.078125 | 641 | News Article | Science & Tech. | 53.256793 | 95,515,322 |
At the end of the article, you will able to know – What are d Block and f Block Elements, Periodic Table, Learn to way how to write the electronic configuration of d block elements and f block elements. Let’s start discussing one by one.
We all know that the long form of the periodic table has been divided into four blocks.They are named as s block, p block, d block and f block. An element in a particular block depends upon its valence shell configuration. Each group is an independent group. The d block elements are known as transition elements. These are placed in 3 – 12 groups of the periodic table.
A further look at the periodic table reveals that both the periods of F- block are basically apart of the elements belonging to group 3. The first series of elements (known as lanthanoids follow lanthanum (La) of d block. Similarly, the elements included in the series known as actinoids follow actinium (Ac) of d block.
see url D Block and F Block Elements
D block is present in the center of the periodic table and has metals of s-block on the left and nonmetals of p-block on the right. This is true for all the elements included in the d block except for those present in group 12. These are Zn, Cd, and Hg. They have completely filled d-orbitals (do configuration). They differ in many characteristics as compared to rest of the elements belonging to the same period. But being end elements, they have been retained in the d block.
Similarly, the elements present at the bottom of the table are included in the f block. There are two series, each having fourteen elements because f -subshell can have a maximum of fourteen electrons.In a case of the d- subshell is partly filled, the elements are called as d block elements; and when the f-subshell is partly filled, the elements are called as f block elements.
traduction de se rencontrer en espagnol What are D – handicap dating kostenlos Block Elements?
A transition element is defined as the one which has incompletely filled d-orbitals in its ground state or in any of its oxidation states. OR
It is defined as the elements of those atoms in a ground state or ion in one of the common oxidation states, has partially filled d subshell i.e having electrons lie between 1 to 9.
There are four transition series starting with electronic configuration, 3d, 4d, 5d and 6d respectively.
http://bti-defence.com/litak-tak-id/ First transition series or 3d-series
Elements from atomic number 21 to 30 are included in this series. There are 10 elements in this series viz., Sc (21), Ti(22), V (23), Cr (24), Mn(25), Fe(26), Co (27), Ni(28), Cu (29) and Zn(30) corresponding to the filling of 3d-subshell.
http://foodintravel.it/integrale-o-raffinato?_sm_byp=iVV1MMS0FwM6QwFs%252527 Second transition series or 4d-series
Elements from atomic number 39 to 48 are included in this series. There are 10 elements in this series viz., Y (39), Zr (40), Nb (41), Mo (42), Tc (43), Ru (44), Rh (45), Pd(46), Ag (47) and Cd (48) corresponding to the filling of 4d-subshell.
source link Third transition series or 5d-series
Elements with atomic number 57 and from 72 to 80 are included in this series. There are 10 elements in this series viz., La (57), Hf (72), Ta (73), W(74), Re (75), Os (76), Ir (77), Pt (78), Au (79) and Hg (80) corresponding to the filling of |-subshell. Elements from 58 to 71 are f block elements because, after the filling of one electron in 5d-subshell in La (57), 4f subshell starts filling with elements having atomic numbers from 58 to 71. These are called Lanthanoids because they follow lanthanum (La) with Z = 57.
enter Fourth transition series or 6d-series
Elements with atomic number 89 and from 104 to 112 are included in this series. These are : Ac(89), Rf (104), Db(105), Sg(106). Bh(107), Hs(108), Mt(109), Ds(110), Rg(111), Uub(1,12). The characteristics of some of these elements are still to be established. Therefore, enough information is not known about them. Elements from 90 to 103 are present in f block (filling takes place in 5f sub-shell). These are known as Actinoids because they follow actinium (Ac) with Z = 89.
get link Electronic Configuration of d block elements
The general valence shell configurations of transition elements is (n-1)d1–10.ns1-2.
mps trading on line Refer to the following video for electronic configuration
Depth knowledge of transition metals under following subtopics:
http://bowlnorthway.com/?jisdjd=opzioni-binarie-conti-demo&9ac=7b What are http://ligaspanyol.net/?mikroskop=site-de-rencontre-belge-en-ligne-gratuit&bfa=d6 F – Block Elements?
These are http://agauchepourdevrai.fr/?fuier=xxl-turbo-flirt-entre-femmes&712=43 known as inner transition elements. In a case of F-block elements, the incomplete subshells are (n-2) f and (n-1) d subshells.In other words, the number of electrons in the outermost shell (n) of the transition elements remains same and hence these elements show nearly similar chemical properties (recall that chemical reactivity depends on the number of electrons in the outermost shell).
Electronic Configuration of F block elements
General electronic configuration of f – block elements is (n–2)f1–14(n–1)d0–1ns2
- Lanthanides: [Xe]4f1–145d0–16s2
- Actinides: [Rn]5f1–146d0–17s2
diclofenac dispers 50 mg Refer to the following video for electronic configuration
Depth knowledge of F block: Lanthanoids and actinoids under following subtopics:
This is all about the basics of – diclofenac alter 50mg What are d Block and f Block Elements, Periodic Table, Learn the way how to write the electronic configuration of d block elements and f block elements.
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For a country like Nepal, with extreme geological fragility and unsustainable development practices, landscape destruction is nothing new. Such fragility was further compounded by Nepal’s devastating earthquake in 2015 and caused a large number
recently visited the landslide dam in Chin State, Myanmar to assess the risk associated with the dam and to develop a comprehensive management plan. Conditions of the lake, landslide dam features, dam materials, the river course and
prone to soil erosion and landslides. landslides pose a serious issue. Not only do landslides impact land productivity due to loss of mountain
hours of 2 August 2014, a landslide occurred above Jure village, about 1.4 km upstream from the Sun Koshi Hydropower project’s intake site. In an instant, a 1.9 km long slope of land perched 1,350 m above the river bed collapsed, burying
Abdur Rahim, a victim from the Lebubagan area, described the landslide of 2007: “It rained continuously for a week and then, one morning, the hills fell apart in quick succession from three sides...
The landslide early warning system developed by the BUET-JIDPUS will help authorities to reach out to these communities on time to alert and relocate them.
a one day field visit to the landslide dam site at Jure for rapid assessment of the landslide, landslide dam, and the newly
earthquake caused numerous landslides and triggered avalanches that caused widespread damage, although much less than what would be expected given
Web-based Landslide Early Warning System for the Chittagong Metropolitan Area
These geohazards include landslide‐dammed rivers, future mass movements (landslides/debris
Landslides are among the hazards that occur after an earthquake. Imagery of Landslides and other natural hazards related to the earthquake are posted as they become available...
Monsoon season in South Asia has become a mixed blessing of late as heavy rains are needed for crop production, but also trigger floods and landslides that often negate the gains made through agriculture.
We made a UAV flight plan and launched the optical UAV flight twice to cover the debris part of the glacier. I was trained on how to make a flight plan, launch UAV, and monitor the progress of the flight through eMotion using area map and the flight
Timely and accurate mapping of floods is important for efficient and effective management of rescue and relief activities. It can help reduce loss and damage due to floods.
The Koshi River basin contains rich biodiversity and is a source of ecosystem services that sustain the lives and livelihoods of millions of people in China, India, and Nepal. The basin plays a key role in the irrigation of downstream areas and has
ICIMOD provides technical guidance and support on using geographic information system (GIS) tools in planning at the sub-watershed level to implement Local Adaptation Plans of Action (LAPAs) being rolled out in six districts in Western Nepal: | <urn:uuid:12dd4b26-4e10-4b09-9fda-07635ac408fe> | 2.96875 | 630 | Content Listing | Science & Tech. | 35.005 | 95,515,340 |
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RE: Sulfate 'n soot kills dinos!
Tom, et al:
One thing to be considered is the trajectory of the bolide. If the angle of
approach to the Earth's atmosphere is sufficiently shallow (but not so
shallow that the bolide skips out of the atmosphere), the ozone layer can be
reduced to 10% of its normal amount (most likely via ionization). This
would be prior to the actual impact onto the Earth's surface. [This study
(a computer model actually) was once mentioned in a nature special - Dr.
Bill Gallagher was the host].
After the actual impact into the surface (land & water), then the soot and
dust, etc. would also deplete the ozone layer even further. Once the skies
had cleared (after the greenhouse effect, etc.), the lack of ozone would
mean Ultraviolet radiation would shine on the earth virtually unhindered.
This would cause really, really bad sunburn to anything still wandering
The acid rain has been part of the scenario (K-T extinction via bolide
collision), about 2 years after the Alvarezes first brought out the initial
Besides that, the increased UV radiation, and other radiation (X-ray, Cosmic
Rays, Solar Flares, etc.), the surviving creatures would most likely have
increased mutation rates. This would certainly enable rapid evolutionary
One signature from this event (specifically the soot) would be the presence
of "Bucky Balls" (in certain fossils).
Hope this helps.
From: email@example.com [mailto:firstname.lastname@example.org]On Behalf Of
Sent: Saturday, March 16, 2002 9:23 PM
Subject: Re: Sulfate 'n soot kills dinos!
> According to Kevin Pope in _Impact dust not the cause of the
> Cretaceous-Tertiary mass extinction_, Geology, Feb 2002, pp99-102, impact
> dust is not the cause of the Cretaceous-Tertiary mass extinction.
Haven't read the paper althouhg I have the issue in question but you have
So before I get clobbered for what follows, I am speaking in only VERY
terms. The K-T impact and impact-extinctions for that matter ar beleive it
the other obsession in my research and one that I spent much time on before
Arundel project went into high gear. Thus, all of my K-T refs are somewhere
not readily available.
> Can anyone tell me how this works--
> Is there lots of acid rain (frog-killing acid rain)?
I would assume so. There have been a couple papers in Both Geology and
but I do remember one that rebutted the Strangelove Ocean hypothesis.
I'd say some major acid rains followed for some time. Retallack had a paper
Geotimes on this .
> Do all forests start burning, even wet tropical forests?
Absolutely! There was a Nature paper called something like "Wildfires at the
K-T..." ca. 1991 with a bunhc of calculations that showed even wet forest
within a certain range could spontaneously ignite as a result of thermal
radiation. And speaking from a Nuclear bomb point of view (another interest
have, there is hard data that shows that from say a 10 MT thermonuclear
thermal radiation is capapble of causing spontaneous ignition in dry
to 30 mile from ground zero. Naturally a much closer ranges, moist material
water containing objects like people also flame up spontaneously too. Ouch!
> What is the length of time sulfate remains aloft compared to dust?
I _think_ the "half-life" of sulfate aerosols is only a few years. For
the aerosols lofted by Mt. Pinatubo hung around for a couple years but their
profound effects were within the first year with a measured cooling of the
> Is this modeled anywhere?
Mostly based on volcanic models involving but I do seem to remember a much
publicezed and controversial experiment carried out in Canada a few years
when Sagan was alive (and who pushed for it) to test the so called 'Nuclear
Winter' hypothesis. It seems some vast forrested part of the Great White
was taken over by some "scrub" trees and they wanted to torch it to see if
particulates released from this burning could be detected in the global
things and to see if (scaled up a few orders of mag) could influence the
After some controversey with some environmentalists and others of the
of this, it finally did occur but the results, IIRC were not that great. Oh,
before I forget, the other imperative for torching this vast chunk of trees
to remove the invading shrubs and allow for the recolinization of native
a tactic used widely. The difference was the considerably larger scale.
> Does rain take it out of the atmosphere?
Over a few rears to deacdes yes.
> Would you expect a global signature--is there one?
> Does this fit the extinction pattern as-well-as, or better-than, the dust?
I am sure is was a major contributing factor but there are some aspects of
that I am not so sure about and likely have forgotten about since my
has long since turned elsewhere. I'll _try_ to look for them later this week
so whilke I am doing my Spring cleaning!
Thomas R. Lipka
2733 Kildaire Drive
Baltimore, Md. 21234 USA | <urn:uuid:429c44e1-3479-417a-9920-6a1fa63a1c82> | 2.625 | 1,225 | Comment Section | Science & Tech. | 54.103221 | 95,515,349 |
Fire-risk reduction practices of California's iconic shrubland ecosystem disrupt wild bird populations, new research shows.
A group of forestry students are helping restore the steep incline that overlooks Berkeley's Memorial Stadium.
New research creates a genetic snapshot of California’s honey bee populations, charting 105 years of change for this essential pollinator species.
Justin Brashares explores the social and cultural impacts of declining wildlife populations around the world, from fish to carnivores.
Adela de la Torre will become the ninth permanent president of SDSU and the first woman to serve in that role.
A new study argues for more prescribed fires, mechanically thinning forests, and physically removing dead trees to combat the threat of fire.
ESPM Professor Allen Goldstein awarded prestigious research grant from the Humboldt Foundation which promotes collaborative research with German scientists.
A new study by CNR researchers demonstrates that the impacts of oil palm expansion on forests is much worse than previous thought.
Drones will play a key role in assessing the impact of highly variable water resources around the state thanks to a new $2.2 million grant from the Gordon and Betty Moore Foundation.
Will China’s crackdown on imported scrap force the US to recycle more of our waste?
A research expedition tracked endangered tigers through the Sumatran jungles for a year and found tigers are clinging to survival in low density populations. Their findings have renewed fears about the possible extinction of the elusive predators.
If our farms are going to feed a growing planet without hastening climate change, says Professor Claire Kremen, they need to transition to diversified agricultural practices.
Scott Silva tells us about his efforts at the Zero Waste Research Center, attending Forestry Camp, and how geocaching led him to study environmental science.
The study will use integrated, collaborative research to promote economic and ecological resilience for urban farms.
A new study from professor Steven Beissinger suggests that many of the state’s birds are adapting to rising temperatures by breeding earlier than they did a century ago.
PG&E Foundation funds smartphone app from Matteo Garbelotto’s lab.
Laura Driscoll tells us about her dissertation research, the organic farming report that she co-authored, and how studying anthropology sparked her interest in ecology.
Without land-use policies to limit its environmental footprint, the impacts of cannabis farming could get worse, according to a new study.
The three-year grant is part of the Innovations at the Nexus of Food, Energy, and Water Systems program.
The new institute will be led by former National Parks Service Director Jon Jarvis. | <urn:uuid:64d48a45-775c-4687-b4a1-e33e6c68fab5> | 2.703125 | 540 | Content Listing | Science & Tech. | 33.370758 | 95,515,374 |
Scientists find a new dinosaur with well preserved, bird-like wings - but not for flight
Paleontologists working in China have found a new dinosaur with one of the most complex, well-preserved set of wings ever seen on a specimen of its size. In a study published Thursday in the journal Scientific Reports, the researchers describe Zhenyuanlong suni, a cousin of the famed Velociraptor that lived around 125 million years ago.
The new species is part of the group — known informally as raptors — that would precede birds, the only dinosaurs remaining on Earth today.
Many smaller species in the group have been found with long forelimbs and feathered wings, indicating that they might have flown. But bigger species in the group tend to have shorter forelimbs not well-suited for flight, and paleontologists had never found feathers on one of those big-boned raptors — until now.
Zhenyuanlong suni probably didn’t fly, according to researchers’ analysis of its fossilized remains. Its arm structure couldn’t have supported its five-foot-long body with the kind of muscle-powered flight that birds use today. But that doesn’t make the fossilized remnants of intricate feathers less exciting: It indicates that other members of the raptor family could have had feathers, too — even the ones not suited for flight.
“This new dinosaur is one of the closest cousins of Velociraptor, but it looks just like a bird,” study co-author Steve Brusatte of the University of Edinburgh’s School of GeoSciences said in a statement. “It’s a dinosaur with huge wings made up of quill pen feathers, just like an eagle or a vulture. The movies have it wrong — this is what Velociraptor would have looked like too.”
The debate over how many dinosaurs were feathered is ongoing. We know that birds must have had a common dinosaur ancestor with feathers, and scientists have found some fossils that take us pretty close to where feathers might have first evolved — but they still aren’t sure exactly when feathers first emerged in dinosaurs, or for what purpose. If they first evolved for warmth or decoration and later were adapted to allow bird ancestors to fly, it’s possible that most dinosaurs had feathers, albeit simple, quill-like ones.
Zhenyuanlong suni didn’t have wings well suited for flight — but it did have the feathers one would need to get off the ground. Because of this, they suspect that suni came after a flying ancestor, losing the capability for muscle-powered flight but retaining the related plumage, perhaps to use its wings for mating displays. | <urn:uuid:434216ec-e097-4767-bcf7-5cb70cb8a983> | 3.671875 | 575 | News Article | Science & Tech. | 41.563333 | 95,515,388 |
NASA scientists using the Swift satellite have conducted the first complete census of galaxies with active, central black holes, a project that scanned the entire sky several times over a nine-month period.
The all-sky survey contains more than 200 supermassive black holes called Active Galactic Nuclei, or AGN, and provides a definitive census of black hole activity in the local universe. The team uncovered many new black holes that were previously missed, even in well-studied galaxies, and other surprises as well.
"We are confident that we are seeing every active, supermassive black hole within 400 million light years of Earth," said Jack Tueller of NASA’s Goddard Space Flight Center, Greenbelt, Md., who led the effort. "With each passing month, we are able to probe deeper into the universe, and the census becomes richer."
AGN have a mass of millions to billions of suns, which are confined within a region about the size of our solar system. The term "active" refers to the process of actively pulling in gas and whole stars and generating copious amounts of energy from a tiny galactic core in the process. Examples include quasars and Seyfert galaxies.
Swift was built primarily to study gamma-ray bursts. During waiting times between bursts, Swift's Burst Alert Telescope, which is sensitive to the highest-energy X-rays, scans the sky. AGN generate X-rays as well as many other forms of light. Many AGN, however, are hidden behind dust and gas, which block lower-energy light, such as visible light. Because higher-energy X-rays are so penetrating, Swift can detect AGN missed by other surveys, allowing for an unbiased count.
Nearly every massive galaxy seems to have a supermassive black hole, but only a few percent appear to be active. Our galaxy's central black hole is dormant, and this and similar black holes are not included in the Swift census. All black holes were likely once active, and why some remain active and others are dormant in the modern, local universe is a mystery.
"You can't understand the universe without understanding black holes," said Richard Mushotzky of Goddard, a census team leader. "Perhaps as much as 20 percent of all of the radiated energy in the universe---most X-rays, large fractions of ultraviolet and infrared light, and a good deal of radio waves---arise in one way or another from AGN activity."
One key census finding is the discovery of AGN in starburst galaxies, which are bright from star formation. These dust-enshrouded AGN, uncovered by Swift, will enable a detailed test of the idea that black hole activity and star formation go hand in glove, feeding each other. Swift also sees hints of cocooned black holes, so embedded in dust that they are completely invisible except in the higher-energy X-ray band.
The initial census results, from data collected in 2005, are a "first taste of things to come," Tueller said. Each scan of the sky is stacked atop existing scans, equivalent to a long camera exposure, so black holes from deeper in the universe will eventually be detected.
Swift builds upon two other surveys. The European INTEGRAL satellite completed a high-energy X-ray survey earlier in 2006, although this focused on the galactic plane and not the whole sky. NASA's Chandra X-ray Observatory conducted a lower-energy X-ray survey of a small fraction of the sky, providing a sample of the more-luminous black holes that formed in the early universe.
Swift also carries X-ray and ultraviolet/optical telescopes, enabling quick confirmation of new active galaxy candidates. This broad coverage in three wavelength regimes is critical for black hole studies.
"The Swift black hole catalogue can be used in a thousand ways," said Craig Markwardt of Goddard and the University of Maryland, who combined the nine-month Swift data into all-sky images. "It's hard to believe the whole sky is peppered with black holes. You need powerful X-ray vision like Swift's to see them."
A NASA Goddard team presents this census at a press conference today in San Francisco at the American Astronomical Society's High Energy Astrophysics Division meeting.
Source: by Christopher Wanjek, NASA/Goddard Space Flight Center
Explore further: Researchers capture best ever evidence of rare black hole | <urn:uuid:1c72a337-efb9-412d-8804-6e53e9b47f2e> | 3.8125 | 909 | News Article | Science & Tech. | 40.034679 | 95,515,399 |
By Aaron Hilf-UNM
As the need for alternative forms of energy production continues to increase around the world, researchers at The University of New Mexico are working to improve hydrogen fuel cells by better understanding them at the atomic and molecular level.
Kateryna Artyushkova, a research associate professor in UNM’s Department of Chemical and Nuclear Engineering, received more than $200,000 from the National Science Foundation’s (NSF) Established Program to Stimulate Competitive Research (EPSCoR). The fellowship will help Artyushkova build a collaborative partnership with the Lawrence Berkeley National Laboratory’s Advanced Light Source facility, giving her the ability utilize instrumentation that will provide a rare glimpse into the inner workings of fuel cells.
“I am very excited about this opportunity as it extends my capacity and the capacity of my students to conduct scientific research in this area,” said Artyushkova. “I am looking forward to the opportunity to be at the forefront of this research that is driven by unique capabilities available only at such facilities as Advanced Light Source of Lawrence Berkley National Laboratory.”
Fuel cells function by converting the chemical energy of the hydrogen fuel into electrical current that can be used in a variety of applications. To do this, the fuel must undergo electrochemical reactions, stripping the hydrogen of its electrons and giving them to oxygen to make water. Artyushkova says it’s the catalyst that spurs these reactions that have the most significant impact on the overall performance of the fuel cell.
To build better, more efficient systems, researchers plan to take a closer look at the chemistry and structure of the catalyst being used in these fuel cells. The instrumentation at the Advanced Light Source facility will give the UNM team the opportunity to probe the catalyst while the reaction is taking place.
“The ability to characterize interfaces in fuel cells at the atomic and molecular levels under realistic operational conditions is the key to tackling some of the most fundamental and profound problems in nature as well as electrochemistry,” said Artyushkova.
According to NSF, these Research Infrastructure Improvement Track-4 fellowship awards total more than $5-million and will provide funding to 30 non-tenured researchers across nearly two-dozen states. | <urn:uuid:15391144-5437-4d1f-8b08-6120b7651aba> | 2.546875 | 472 | News (Org.) | Science & Tech. | 13.884572 | 95,515,426 |
The Effects Of Climate Change
Another change that has been predicted is that flowers will start to bloom earlier and generally that natural cycles will be disrupted. Whilst this might not harm some species and creatures for every winner there will be a loser and it may be that some simply cannot adjust to the new order and therefore there could be an increasing rate of extinctions which is bad news for all of us.
One of the impacts that it less well documented is to do with space junk. Space junk is staying in orbit longer than it used to which means that there is more of it there too. This is because the atmosphere is reducing in density at a certain key distance above the earth and therefore there is less molecular braking which means that the junk stays up there longer.
This is potentially significant as the more debris there is the more potential hazardous impacts there will be for other spacecraft.
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Thermal Power And Generating Your Own Energy | <urn:uuid:dbafb4c4-9fdb-472e-a0df-434482e0c367> | 3.390625 | 222 | Content Listing | Science & Tech. | 32.652314 | 95,515,437 |
Many people new to Postgres are confused by the security model. They understand the SQL commands that use GRANT, CONNECT and REVOKE to alter permissions (the SQL DSL, or Data Security Language component of SQL) because that is common across various SQL Database Engines. However, Postgres has another layer of security that you need to successfully navigate first.
== pg_hba.conf ==
Postgres uses a configuration file, called the pg_hba.conf file, that identifies how each user (or users) can connect to each database in the postgres engine. It identifies what system (or systems) the user(s_ can connect from what systems and also specifies the authentication method they use for that database. In wriitng (and revising this), it sounds complex, or maybe it's just my style of writing. But the below description should make it clearer.
Basically there are four fields that are checked:
- User connection source
- Authentication mechanism
The sample file below (with explanation) may help understand the different methods and sources:
local all postgres ident local music_db music md5 local all dbadump trust #local all all ident sameuser local all all ident
This means that the user _postgres_ can connect locally (over a Unix Socket) to any database, and you will trust that the Operating System has already identified the user (the ident method).
The user _music_ can connect locally to the database music_db using a password encrypted in postgres (the password is encrypted using md5).
The user _dbadump_ can connect locally to any database and is trusted into that database. This is a potential security issue as ANY user on the local system can claim to be the user _dbadump_ and connect to any database. (You'd have to rely on SQL DSL and GRANT permissions to restrict their access at this point!)
The next line is a comment. So it is ignored by engine, but you can use it to document your configuration file if you so wish.
The last line says that any other system user (Linux or Windows) can connect locally to any database (again, their permissions should be controlled through DSL inside each database).
One thing to note (and is specified in the Postgres documentation) is the permissions should be going from MOST restrictive (the tightest definition) to the LEAST restrictive (the potential for more people to match the "rule"). The reason is that the first rule that matches (whether they successfully log in or not!) determines which rule APPLIES (and no further checking occurs!).
Now that I've shown what happens when you connect locally (over a Socket), we'll talk about REMOTE (from another computer) connections.
# IPv4 local connections: host all all 127.0.0.1/8 md5
Any user that connects to any database using localhost (127.0.0.1 to 127.255.255.255) will use an encrypted password stored in Postgres.
A word of warning on this one - I've used the network of 127.*.*.* instead of just 127.0.0.1/32 because some Linux distributions define the localhost (or even the hostname) with something else in the 127.*.*.* network. If you choose to use a CIDR Address of 127.0.0.1/32 or 127.0.0.1/24 (anything between 127.0.0.1 and 127.0.0.255) you could exclude some addresses where they would connect with a different rule.
host music_db music 192.168.1.53/32 md5 host music_db music 192.168.1.55/32 md5 host all timothy 192.168.1.1/24 md5 host all dbauser 192.168.1.50/32 trust hostssl all admin 126.96.36.199/0 md5
The user _music_ can connect to the database music_db from either 192.168.1.53 or 192.168.1.55 (and they can authenticate or prove who they are by providing a password that matches their password stored in postgres and encrypted using the md5 algorithm).
The user _timothy_ can connect to ANY database from any computer with an IP Address between 192.168.1.1 and 192.168.1.255. (NOTE: This is only on the local network. If you connect over the Internet, which I will show later, you will have a different EXTERNAL IP Address that the database engine will see.)
The user _dbauser_ can connect to any database from the IP Address of 192.168.1.50 ONLY. But any user that claims to be _dbauser_ on that system will be explicityly trusted into the engine.
The user _admin_ can connect from ANY IP Address in the world and will be able to prove who they are by providing a password that matches up with what is already encrypted and stored inside Postgres. The only difference between this and previous "host" entries is that the connection is encrypted using SSL (Secure Sockets Layer). There is additional overhead associated with using encryption, but especially across the Internet, you really should encrypt the whole session (especially the authentication piece so you don't send a password across the Internet in plain text).
The last line is similar, but it authenticates against a LDAP souce rather than having the password stored in postgres.
== Roles ==
Once the user has a connection to the server/database, a second mechanism is used to identify what objects they can access, basically where they have permissions to view or update data. This is the Data Security Language (DSL) portion of SQL. This is where you allow a user to CONNECT to a database or read data (SELECT permission) or update data (UPDATE or DELETE permissions). These permissions are well explained in the documentation for Postgres or any other SQL Database engine. | <urn:uuid:4adb775b-8278-477d-93e4-3ada68fa812c> | 2.6875 | 1,257 | Documentation | Software Dev. | 66.298614 | 95,515,438 |
Just inland from the familiar salt-loving mangroves that line the Southern tip of the Florida Peninsula lie plant communities that depend on freshwater flowing south from Lake Okeechobee.
The study area, including the Southern Everglades, Florida City, Key Largo and other parts of Florida Bay and the upper Keys. Credit: CSTARS / Doug Fuller
These communities provide critical habitats to many wildlife species, and as salt water intrudes, it could spell problems for freshwater plants and animals alike.
Satellite imagery over the southeastern Everglades confirms long-term trends of mangrove expansion and sawgrass habitat loss near the shore. The trend is related to salt water intrusion caused by sea-level rise and water management practices, according to a new study published in the scientific journal Wetlands.
“I was very surprised at how well the results matched our understanding of long-term trends and field data. Normally, we don’t see such clear patterns,” said Douglas Fuller, principal investigator of the study.
The findings show large patches of vegetation loss closer to the coast, approximately four kilometers from the shoreline, in and around a vegetative band of low productivity that has been shifting inland over the past 70 years. Growth trends were seen primarily in the interior, at about eight kilometers from the shore.
“Less salt-tolerant plants like the sawgrass, spike rush, and tropical hardwood hammocks are retreating. At the same time, salt-loving mangroves continue to extend inland,” said Fuller, professor of Geography and Regional studies in the College of Arts and Sciences at the University of Miami.
Changes in water management, such as the implementation of the Comprehensive Everglades Restoration Plan, may help offset the possible effects caused by future salt water intrusion. “However, restoration may not suffice if sea-level rise accelerates in the coming decades,” Fuller said.
Fuller and co-author Yu Wang, a former master’s student at UM, used satellite imagery from 2001 to 2010 over the southeastern Everglades, in an area called Taylor Slough, which is the second-largest flow-way for surface water in the Everglades, and stretches about 30 kilometers along the eastern boundary of Everglades National Park.
“These methods allowed us to perform a spatially comprehensive assessment of the trends, unlike research that has been limited to plot-level studies, in which careful measurements of plant cover and composition have been made over the past dozen years,” Fuller said. “These field studies, which provide confirmation of the satellite-based results, involved clipping and weighing plants found in sawgrass prairies and are part of a long-term effort to understand the dynamics of the ecosystems in the Everglades.”
The findings are shared in a paper titled “Recent Trends in Satellite Vegetation Index Observations Indicate Decreasing Vegetation Biomass in the Southeastern Saline Everglades Wetlands.”
In the future, the researchers would like to apply the methods used in their study to other coastal wetland areas that are threatened by sea-level rise.
Annette Gallagher can be reached at 305-284-1121.
Annette Gallagher | EurekAlert!
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A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
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20.07.2018 | Materials Sciences | <urn:uuid:bb7ad407-013b-4964-97aa-96d10d5a7265> | 3.421875 | 1,272 | Content Listing | Science & Tech. | 35.118238 | 95,515,445 |
Since 1992 the LIFE programme has supported nature projects that benefit invertebrates. Many projects have directly targeted the conservation needs of species listed in Annexes II and IV of the Habitats Directive. In 2011 a platform meeting on terrestrial invertebrates was held in the UK to share experience across Europe. An immediate outcome of the meeting was the opening up of the LIFE programme to species listed in the IUCN Red List of Threatened Species.
Now, it is time to review how well LIFE has targeted actions for threatened invertebrates and to consider what more could the programme do to support these sometimes forgotten species groups. To this end, the European Commission is holding a platform meeting on threatened invertebrates at the STEP Scotland Business Enterprise, Stirling. ‘Bringing Bugs Back to LIFE’ will be hosted and co-organised by the EcoCo LIFE+ project.
As well as the IUCN lists of butterflies, dragonflies and saproxylic beetles discussed at the 2011 platform, this meeting will cover the IUCN lists for bees, grasshoppers, spiders and terrestrial molluscs.
LIFE projects are invited to participate in the meeting which will address the following questions:
The discussions and outcomes of the meeting will be considered by the European Commission in developing its ideas for the next LIFE Regulation.
The two-day event will include plenary sessions, thematic workshops, excursions and posters. It will also provide opportunities for networking and for proposing priorities for future LIFE projects.
For further information contact the EcoCoLIFE+ project coordinator: Paul Sizeland
Volunteers play a crucial role in the success of the LIFE programme. LIFE Nature and Biodiversity projects in particular have benefited from the ability of nature conservation NGOs to leverage their networks of volunteers.
The main objective of this LIFE platform meeting is to share experience between LIFE projects and to identify what is most important for increasing the impact of volunteers in nature conservation. It is hosted by the wetland conservation project, LIFE Mires Estonia, which is coordinated by the Estonian Fund for Nature. More than 500 people are taking part in volunteer camps to help the NGO restore Estonia's wetlands.
The three-day event will include plenary sessions, thematic workshops and a poster session presenting and discussing the experiences of projects from several EU countries. Invited experts will highlight the work of other programs that involve volunteers and offer lessons on attracting, motivating and utilising volunteers. The meeting will also explore the social aspects of volunteering and make links with other policy areas. It will provide excellent opportunities for networking and feature the possibility to work as a volunteer for a day helping to build dams in a mire.
For further information visit the meeting’s website. Registration closes on 20 July 2018.
The European Union has set ambitious targets for reducing greenhouse gas (GHG) emissions by 2020, 2030 and 2050, in response to global efforts spearheaded by the United Nations Framework Convention on Climate Change (UNFCCC), its Kyoto Protocol and the recent Paris Agreement.
Energy intensive industries play a critical role in achieving these targets. This LIFE platform meeting will bring together beneficiaries of the LIFE programme and other EU funding mechanisms, policymakers and stakeholders to discuss how energy intensive industries can contribute to realising the EU roadmap to eventual decarbonisation. The discussions and networking will facilitate exchange of good practices and synergies between projects that are designed to increase energy efficiency and reduce GHG emissions, in particular in the cement, ceramic, glass, steel and metal industries.
The meeting is hosted by LIFE OPTIMELT, a project that is recovering waste heat in glass manufacturing, and is organised in cooperation with the Executive Agency for Small and Medium-sized Enterprises (EASME) and the European Commission's Directorate-General for Climate Action (DG CLIMA).
The two-day gathering will include plenary sessions on the policy context, industry commitments and technological solutions; workshops; a poster session; and field visits to the OPTIMELT project at the Libbey Leerdam glassware factory and Tata Steel’s Horizon 2020 project, HIsarna, both in the Netherlands
To download a copy of the preliminary agenda, click here.
For further information contact: firstname.lastname@example.org | <urn:uuid:3f4a5bde-4584-4953-953f-e02b4cb08b97> | 2.578125 | 874 | News (Org.) | Science & Tech. | 22.504783 | 95,515,449 |
These computer tools, based on the notion of "formal proof", have in recent years been used to provide nearly infallible proofs of many important results in mathematics.
A ground-breaking collection of four articles by leading experts, published today in the Notices of the American Mathematical SocietyNotices of the American Mathematical Society (http://www.ams.org/notices), explores new developments in the use of formal proof in mathematics.
When mathematicians prove theorems in the traditional way, they present the argument in narrative form. They assume previous results, they gloss over details they think other experts will understand, they take shortcuts to make the presentation less tedious, they appeal to intuition, etc. The correctness of the arguments is determined by the scrutiny of other mathematicians, in informal discussions, in lectures, or in journals. It is sobering to realize that the means by which mathematical results are verified is essentially a social process and is thus fallible. When it comes to central, well known results, the proofs are especially well checked and errors are eventually found.
Nevertheless the history of mathematics has many stories about false results that went undetected for a long time. In addition, in some recent cases, important theorems have required such long and complicated proofs that very few people have the time, energy, and necessary background to check through them. And some proofs contain extensive computer code to, for example, check a lot of cases that would be infeasible to check by hand. How can mathematicians be sure that such proofs are reliable?
To get around these problems, computer scientists and mathematicians began to develop the field of formal proof. A formal proof is one in which every logical inference has been checked all the way back to the fundamental axioms of mathematics. Mathematicians do not usually write formal proofs because such proofs are so long and cumbersome that it would be impossible to have them checked by human mathematicians. But now one can get "computer proof assistants" to do the checking. In recent years, computer proof assistants have become powerful enough to handle difficult proofs.
Only in simple cases can one feed a statement to a computer proof assistant and expect it to hand over a proof. Rather, the mathematician has to know how to prove the statement; the proof then is greatly expanded into the special syntax of formal proof, with every step spelled out, and it is this formal proof that the computer checks. It is also possible to let computers loose to explore mathematics on their own, and in some cases they have come up with interesting conjectures that went unnoticed by mathematicians. We may be close to seeing how computers, rather than humans, would do mathematics.
The four Notices articles explore the current state of the art of formal proof and provide practical guidance for using computer proof assistants. If the use of these assistants becomes widespread, they could change deeply mathematics as it is currently practiced. One long-term dream is to have formal proofs of all of the central theorems in mathematics. Thomas Hales, one of the authors writing in the Notices, says that such a collection of proofs would be akin to "the sequencing of the mathematical genome".
The four articles are:
Formal Proof, by Thomas Hales, University of Pittsburgh
Formal Proof---Theory and Practice, by John Harrison, Intel CorporationFormal proof---The Four Colour Theorem, by Georges Gonthier, Microsoft
Reversing cause and effect is no trouble for quantum computers
20.07.2018 | Centre for Quantum Technologies at the National University of Singapore
Study suggests buried Internet infrastructure at risk as sea levels rise
18.07.2018 | University of Wisconsin-Madison
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
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12 July 2018
Oxygen loss strains marine ecosystems
Published online 13 January 2018
A new review highlights the impact of declining oxygen levels in the open ocean and coastal waters due to increasing temperatures and nutrient discharge.
Half of the world’s oxygen originates from the ocean. Yet, worldwide, the amount of open ocean without any oxygen has quadrupled over the past 50 years. Oxygen-minimum zones have expanded by several million square kilometres, increasing by more than 10-fold since 1950.
A new study1, published in Science, by a United Nations international working group, the Global Ocean Oxygen Network (GO2NE), is the first to assess of the causes, consequences, and solutions to deoxygenation, or the loss of oxygen, in open oceans and coastal waters. The research team includes Wajih Naqvi, who was affiliated, at the time of the study, with the Kuwait Institute for Scientific Research in Salmiya.
The authors cite greenhouse gas-driven global warming as the most likely cause of widespread deoxygenation in the open ocean.
The increase in ocean temperatures makes it more difficult for oxygen to reach deeper ocean layers. Naqvi says that this particularly affects areas like the Bay of Bengal, which has an existing naturally-caused oxygen deficiency. Further, in coastal areas, increasing runoff from sewage and fertilizer stimulates the growth of marine algae, leading to the excessive production of organic matter.
According to Naqvi, this has led to the development of more than 600 dead zones, areas that are hypoxic or devoid of adequate oxygen, along coasts all around the world.
The expansion of these dead zones shrink the habitat of oceanic organisms, impacting their survival, behaviour, and reproduction. This in turn has lowered the biodiversity and altered the structure of food webs in the oceans. It has also led to the increased production of nitrous oxide, which is a potent greenhouse gas, exacerbating global warming.
Matthew Long, a scientist affiliated with the National Centre for Atmospheric Research in Colorado, who was not a part of the study, says, “the changes in ocean oxygen that are underway now are following a pattern similar to [mass extinction] events in Earth's history. If action is not taken to mitigate climate change, the consequences for marine ecosystems are likely to be catastrophic.”
The study suggests that the impact of deoxygenation should be managed by better monitoring programs, which analyse widespread, real-time measurements over larger ocean areas. It is vital to educate people about curtailing greenhouse gas emissions, and better fertilizer, sewage, and waste management, according to Naqvi. He says, that in the Middle-East, in particular, “increasing discharges of sewage from the sprawling urban/industrial centres that are cropping up all along the shores of the Persian Gulf, have led to hypoxic conditions in the central Gulf, which were not observed previously.”
Long agrees, underscoring the importance of developing “effective social and political institutions to manage and reduce this impact.” He adds, “the most important thing people can do is to demand their elected officials take this issue seriously and pursue effective climate and environmental policy.”
- Breitburg, D. et al. Declining oxygen in the global ocean and coastal waters. Science http://science.sciencemag.org/cgi/doi/10.1126/science.aam7240 (2018). | <urn:uuid:39b09f59-ba91-4888-ba01-f7e25596c9bc> | 3.421875 | 709 | Truncated | Science & Tech. | 31.227677 | 95,515,469 |
The human opportunistic pathogen, Pseudomonas aeruginosa, has broken the immune systems code, report researchers from the University of Chicago, enabling the bacteria to recognize when its host is most vulnerable and to launch an attack before the weakened host can muster its defenses.
In the 29 July 2005 issue of Science, the researchers show how this lethal organism detects interferon-gamma, a chemical messenger the immune system uses to coordinate its efforts to get rid of bacteria. When these bacteria intercept this message, they recognize it as a threat, assess their own numbers and, if they have sufficient strength, activate genes that quickly transform them from benign passengers in the bowel into deadly blood-stream invaders.
"Most of the time these microbes are content to live and grow in our intestines," said John Alverdy, M.D., professor of surgery at the University of Chicago and director of the study. "They dont feel the need or even look for the opportunity to attack. But when they detect a threat, they have a remarkably sophisticated defense plan, based, unfortunately, on the notion that the best defense is an overwhelming offense."
John Easton | EurekAlert!
Colorectal cancer risk factors decrypted
13.07.2018 | Max-Planck-Institut für Stoffwechselforschung
Algae Have Land Genes
13.07.2018 | Julius-Maximilians-Universität Würzburg
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
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Gunnison Sage-grouse Life History
Despite genetic, morphological, and behavioral differences, Gunnison sage-grouse and greater sage-grouse are believed to have similar life histories and habitat requirements. Most research about sage-grouse life history has been performed on greater sage-grouse, and while much of this research is applicable to Gunnison sage-grouse important differences exist between the two species.
Sage-grouse are sagebrush obligate species; they require healthy, functioning sagebrush ecosystems for year round survival. Sage-grouse are also considered indicator species because, if the sagebrush habitat is not healthy, grouse populations also suffer. Due to high levels of natural variation in sagebrush community composition, grouse are adapted to a mosaic of habitats to support their annual cycle (Birds of North America). While most sage-grouse are non-migratory, some birds can move great distances to meet their dietary requirements and find their diverse seasonal habitats (GUSG Range-wide Conservation Plan 2005). Adult Gunnison sage-grouse eat leafy vegetation and will also eat insects in summer. Although sagebrush leaves are their preferred food, grouse will also eat succulent forbs in summer. The winter diet is completely sagebrush based, requiring that some plants in winter habitat reach above the snow. Chicks consume insects and some forbs during brood rearing, and their diet shifts to sagebrush in fall (Birds of North America).
Annual survival rates vary: juvenile survival from hatch to fall is estimated to be 38%. Adult females have higher annual survival rates than males, possibly due to more cryptic plumage and secretive nature, compared to the males' elaborate plumage and display activities (GUSG Range-wide Conservation Plan 2005). As birds age, the male to female sex ratio declines due to lower annual survival rates for males (Birds of North America). Male survival rates are lowest during breeding season and female survival rates are lowest during nesting. Predators include golden eagles, a variety of hawks and accipiters, coyotes, red foxes, and bobcats. Nest predators include corvids, weasels, coyotes and badgers. Nest success is considered the most significant parameter influencing population dynamics (Birds of North America).
The sage-grouse annual cycle begins in mid-March, when the breeding season kicks off. Males congregate on leks, or strutting grounds, which are relatively bare, flat areas in the sagebrush ecosystem with good acoustic qualities and high visibility for females to assess the males' dance and vocalizations. These areas also allow for easy predator detection. Sites are usually located near good nesting habitat and good cover. Males begin to attend leks in early March; however, timing varies depending on snowmelt, weather, and photoperiod. Dominant males establish their position on the lek via wing fights and chases, usually trying to secure positions near the middle of the lek (Birds of North America). Gunnison sage-grouse are highly philopatric, returning to exactly the same spot for generations, even displaying on the ice over the newly created Blue Mesa Reservoir where their lek had previously been (National Park Conservation Association 2011, High Country News 2002). Males congregate to display for females from about an hour before dawn until about an hour after sunrise, with females showing up after males, and leaving while males are still displaying. Males typically do not move more than 1.5 miles from the lek during this time (GUSG Range-wide Conservation Plan 2005).
A lek system is polygamous, meaning females select which male to mate with and the male mates with several females. Approximately 70% of the copulations are by dominant males and only 10-15% of males actually breed (Birds of North America, Gunnison Sage-grouse Local Plan). This has significant conservation concerns because it reduces the effective population size (the number of individuals contributing genes to the next generation) below the absolute population size (the estimated total population) for males. It also limits genetic variation within the population. The lekking season runs from mid-March to late-May, with the highest lek attendance typically occurring in the second week of April. Females begin nesting as soon as they have bred, and the males provide no parental care.
Nesting typically begins late April to the beginning of May; although, in early snow melt years females have laid their first eggs as early as mid-April (Colorado Parks and Wildlife, unpublished data). Research has shown that 70-80% of nests occur within two miles of leks, however, female greater sage-grouse have been found nesting up to 20 miles from their mating lek (Birds of North America). Quality nesting habitat requires live sagebrush with sufficient canopy cover to conceal the nest and a thick forb and grass understory. Often, high vegetative diversity provides the best horizontal and vertical cover, in turn providing greatest protection from visual predators and helping with thermoregulation (Birds of North America, GUSG Range-wide Conservation Plan 2005).
Nests are shallow bowls lined with feathers and leaves at the base of live sagebrush. Clutch size averages 7 to 9 eggs, with yearling females having lower clutch sizes in some populations. Incubation starts once the last egg is laid and occurs for 27 to 28 days (GUSG Range-wide Conservation Plan 2005).
Sage-grouse have some of the lowest nest success rates of all upland game birds, with success rates ranging from 10 to 63% for greater sage-grouse (Birds of North America). Young (1994) reported a 43.2% nest success rate for Gunnison sage-grouse in the Gunnison Basin. Nest abandonment occurs in up to 22% of nests, and is most common when the female is disturbed by human activity (Birds of North America). Re-nesting is infrequent but does occur, with typically lower clutch sizes. Hatching begins in mid-May and usually ends by July, with peak hatch occurring between 10-20 June (GUSG Range-wide Conservation Plan 2005).
Chicks are precocial and leave the nest with the hen within days of hatching. Hens with chicks move to areas containing succulent forbs and insects, often in wet meadows or riparian habitats where cover is tall enough to conceal the brood and provide shade. High quality brood rearing habitat is often classified as having high forb species richness (GUSG Range-wide Conservation Plan 2005). Chick and juvenile survival depend on the availability of food and cover. Insects (primarily beetles, ants and grasshoppers) are the main food source for chicks during the first three weeks of life. From 4 to 8 weeks old, the diet shifts to include plant material, including a variety of succulent forbs and some sagebrush (GUSG Range-wide Conservation Plan 2005). After three months, sagebrush becomes the main dietary component. Adults will also eat some insects during spring and summer; however, forbs and sagebrush dominate their diet.
Unsuccessful nesting females and occasional males will join females with broods in these wet meadows, but are not as dependent on the habitat type. As autumn approaches, flocks and broods intermix as birds move from riparian areas to sagebrush dominated habitats that still provide some green forbs. Sometimes sage-grouse will move into agricultural fields at this time of year. Fringed sagebrush is a common transitional food as grouse shift from summer to winter diets (Birds of North America).
Flock size in winter varies form 15 to 100 birds with flocks often made up of a single sex (GUSG Range-wide Conservation Plan 2005). Many males overwinter within several miles from their lek. From the end of fall through early spring, sagebrush is almost the only component of sage-grouse diets. Almost any kind of sagebrush is consumed, though some birds select various subspecies for higher protein levels and lower monoterpene (plant defense chemical) levels (GUSG Range-wide Conservation Plan 2005). While birds may have low fat reserves after severe winters, individuals gain weight throughout most winters (Birds of North America, Hupp and Braun 1989, Beck and Braun 1978). During harsh winters with high snow accumulation levels, grouse depend on very tall sagebrush that is exposed above the snow. In extreme winters, sage-grouse burrow into snow roosts for protection against the elements. Grouse may associate with ungulates that uncover sagebrush to browse on during the winter (Birds of North America, Patterson 1952).
Gunnison sage-grouse have been documented moving as far as 17 miles to their winter habitat, but movements depend on severity of the winter, topography, and cover (GUSG Range-wide Conservation Plan 2005). Winter habitat requires tall sagebrush, such as that found on ridges, drainages, or southwest aspects. | <urn:uuid:52fb1e2f-5fb4-4eb5-892b-ab68e033cef9> | 4.125 | 1,852 | Knowledge Article | Science & Tech. | 33.335785 | 95,515,476 |
The Burmese peacock turtle is an aquatic turtle found in the lower reaches of the Ayeyarwady (Irrawaddy) River in southern Myanmar and also possibly found as far north as Mandalay and in the Doke-tha-wady at Shwe sar yan. It has a domed shell that reaches around 9 inches in length. Color ranges from light to dark greenish brown. Its underparts are yellow and it has pale yellow eye-like circles that appear on each scute (bony sections covering the shell), giving it it's name. Two yellow streaks appear on each side of the head.
Burmese peacock turtles are found in rivers, swamps, streams, and ponds. Sometimes they are observed stranded on the land during the dry season. Little is known about the reproductive behavior of this species.
Although the species appears to be abundant and are widely available in local markets, it is listed as endangered with the US FWS. Threats to the species may include habitat degradation and overcapture by the Chinese market for medicinal purposes.
Burmese Peacock Turtle Facts Last Updated: May 9, 2017
To Cite This Page:
Glenn, C. R. 2006. "Earth's Endangered Creatures - Burmese Peacock Turtle Facts" (Online).
Accessed 7/16/2018 at http://earthsendangered.com/profile.asp?sp=475&ID=3.
Need more Burmese Peacock Turtle facts?
Ten Creatures that may become extinct in the next 10 years
1. Leatherback Sea Turtle Leatherback sea turtles have been around since pre-historic times. And unfortunately, if the species is allowed to vanish, scientists believe it will foreshadow the extinction of a host of other marine species. It is estimated that there are less than 5,000 nesting female leatherback sea turtles in the Pacific Ocean today, down from 91,000 in 1980. | <urn:uuid:27d3afe9-f0b8-4b37-99ea-3afadd2d3899> | 3.71875 | 404 | Knowledge Article | Science & Tech. | 58.968898 | 95,515,479 |
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Overloading the assignment operator (operator=) is relatively straightforward, with one particular caveat that we’ll reach. The assignment operator needs to be overloaded for a member function.
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Therefore, despite this obvious equivalence concerning array and pointer variables, there is still a difference to generally be made in between them. Though the identify of the array is, for most expression contexts, transformed right into a pointer (to its 1st element), this pointer would not alone occupy any storage; the array name isn't an l-benefit, and its deal with is a constant, in contrast to a pointer variable.
Some common headers do outline more practical synonyms for underscored identifiers. The language Beforehand integrated a reserved word called entry, but this was rarely implemented, and has now been removed to be a reserved word.[twenty five] Operators
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A block is made up of a sequence of statements. Blocks for function bodies in perform definitions; to outline the branches of if statements and the bodies of although loops.
The big number of extensions and insufficient settlement on a regular library, together with the language level of popularity and The truth that not even the Unix compilers exactly executed the K&R specification, led towards the necessity of standardization. ANSI C and ISO C
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Applications such as Purify or Valgrind and linking with libraries that contains Unique versions with the memory allocation features can help uncover runtime faults in memory use. Makes use of | <urn:uuid:6b75ca4b-d8cf-4bfb-b091-6121aa4b5c4e> | 2.640625 | 671 | Spam / Ads | Software Dev. | 31.319189 | 95,515,483 |
Grandmother wants to give the candies to grandchildren that when she gives 5 candy everyone 3 missing and when she gives 4 candies 3 is surplus. How many grandchildren has grandmother and how many candies has?
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Solve the equation: 1/2-2/8 = 1/10; Write the result as a decimal number. | <urn:uuid:358f2318-2886-4ae1-a0cc-88055c31e474> | 3.265625 | 696 | Tutorial | Science & Tech. | 76.024199 | 95,515,487 |
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a graph i made for a lab showed different curves meaning there was a difference in the number of electrons produced in the three samples during the xperiment. how are elctrions genated in photosynthesis and why the three graphs would give different transmittance results?
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Scalar product - examples
Triangle KLM is given by plane coordinates of vertices: K[-4, -18] L[-13, 15] M[-1, 8]. Calculate its area and itsinterior angles.
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The three points A(3, 8), B(6, 2) and C(10, 2). The point D is such that the line DA is perpendicular to AB and DC is parallel to AB. Calculate the coordinates of D. | <urn:uuid:150a4335-98d1-451a-bf15-a6a9e3bf8a7e> | 3.5625 | 217 | Tutorial | Science & Tech. | 94.375531 | 95,515,514 |
It looks like a tiny wagon wheel: Scanning tunneling microscope images published in the journal Angewandte Chemie depict giant molecules with a diameter of 7 nm, whose “hub”, “spokes”, and “rim” are clearly recognizable. This unusual, highly symmetric structure was made by a team led by Sigurd Höger (University of Bonn); the pictures were taken by a Belgian team headed by Steven De Feyter (Kath. Univ. Leuven).
Two-dimensional particles, such as inorganic alumina platelets, are used as fillers for plastics because they impart excellent mechanical properties to these materials. Nanocomposites made of alumina platelets and polymers are thus extraordinarily rigid, strong, and thermally stable materials. The barrier properties of plastics with respect to liquids and gasses, such as oxygen, could be improved by the addition of nanoscopic platelets. This would be useful for applications such as food packaging, and makes less expensive, more environmentally friendly plastics accessible.
To better understand the way in which the platelets work, several researchers have been working with synthetic alumina platelets. One area of interest is the use of large organic molecules in the form of rigid disks. Their advantage: They can be produced with uniform shapes and sizes. Also, their chemical properties can be adjusted as needed by the attachment of additional functional groups. Until now, organic molecular disks could not be made as large as the inorganic originals they are intended to imitate. The team from the Universities of Bonn and Leuven has now jumped this hurdle: They have successfully synthesized very large wheel-shaped molecules.
Starting from a rigid, star-shaped “hub”, the researchers added additional rigid molecular building blocks to form six “spokes”. Finally, the parts of the molecule were connected to form a continuous “rim”. The rigid linear molecules used contain aromatic six-membered rings as well as carbon–carbon triple bonds. Additional groups attached to the spokes provide the solubility required for the experiments to be carried out on these molecules.
In the next step, the researchers will attempt to grow these little wheels bit by bit by adding more building blocks onto the rim. This should result in structures resembling a spider web.
Author: Sigurd Höger, Universität Bonn (Germany), http://www.chemie.uni-bonn.de/oc/ak_ho/
Title: Molecularly Defined Shape-Persistent 2D Oligomers: The Covalent-Template Approach to Molecular Spoked Wheels
NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation
Pollen taxi for bacteria
18.07.2018 | Technische Universität München
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
18.07.2018 | Materials Sciences
18.07.2018 | Life Sciences
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Observations taken with Hubble's Cosmic Origins Spectrograph (COS) suggest powerful stellar winds are sweeping the cast-off atmospheric material behind the scorched planet and shaping it into a comet-like tail.
"Since 2003 scientists have theorized the lost mass is being pushed back into a tail, and they have even calculated what it looks like," said astronomer Jeffrey Linsky of the University of Colorado in Boulder, leader of the COS study. "We think we have the best observational evidence to support that theory. We have measured gas coming off the planet at specific speeds, some coming toward Earth. The most likely interpretation is that we have measured the velocity of material in a tail."
The planet, located 153 light-years from Earth, weighs slightly less than Jupiter but orbits 100 times closer to its star than the Jovian giant. The roasted planet zips around its star in a short 3.5 days. In contrast, our solar system's fastest planet, Mercury, orbits the Sun in 88 days. The extrasolar planet is one of the most intensely scrutinized, because it is the first of the few known alien worlds that can be seen passing in front of, or transiting, its star. Linsky and his team used COS to analyze the planet's atmosphere during transiting events. During a transit, astronomers study the structure and chemical makeup of a planet's atmosphere by sampling the starlight that passes through it. The dip in starlight because of the planet's passage, excluding the atmosphere, is very small, only about 1.5 percent. When the atmosphere is added, the dip jumps to 8 percent, indicating a bloated atmosphere.
COS detected the heavy elements carbon and silicon in the planet's super-hot 2,000-degree-Fahrenheit atmosphere. This detection revealed the parent star is heating the entire atmosphere, dredging up the heavier elements and allowing them to escape the planet.
The COS data also showed the material leaving the planet was not all traveling at the same speed. "We found gas escaping at high velocities, with a large amount of this gas flowing toward us at 22,000 miles per hour," Linsky said. "This large gas flow is likely gas swept up by the stellar wind to form the comet-like tail trailing the planet."
Hubble's newest spectrograph has the ability to probe a planet's chemistry at ultraviolet wavelengths not accessible to ground-based telescopes. COS is proving to be an important instrument for probing the atmospheres of "hot Jupiters" like HD 209458b.
Another Hubble instrument, the Space Telescope Imaging Spectrograph (STIS), observed the planet in 2003. The STIS data showed an active, evaporating atmosphere, and a comet-tail-like structure was suggested as a possibility. But STIS wasn't able to obtain the spectroscopic detail necessary to show a tail, or an Earthward-moving component of the gas, during transits. The tail was detected for the first time because of the unique combination of very high ultraviolet sensitivity and good spectral resolution provided by COS.
Although this extreme planet is being roasted by its star, it won't be destroyed anytime soon. "It will take about a trillion years for the planet to evaporate," Linsky said.
The results appeared in the July 10 issue of The Astrophysical Journal.
The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center in Greenbelt, Md., manages the telescope. The Space Telescope Science Institute, operated for NASA by the Association of Universities for Research in Astronomy, Inc. in Washington, conducts Hubble science operations.
For illustrations and more information about HD 209458b, visit:http://www.nasa.gov/hubble
What happens when we heat the atomic lattice of a magnet all of a sudden?
18.07.2018 | Forschungsverbund Berlin
Subaru Telescope helps pinpoint origin of ultra-high energy neutrino
16.07.2018 | National Institutes of Natural Sciences
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
18.07.2018 | Life Sciences
18.07.2018 | Materials Sciences
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Skip to comments.INFORMATION PARADOX SOLVED? IF SO, BLACK HOLES ARE "FUZZBALLS"
Posted on 03/01/2004 9:21:01 AM PST by AdmSmith
COLUMBUS, Ohio, Stephen Hawking and Kip Thorne may owe John Preskill a set of encyclopedias.
In 1997, the three cosmologists made a famous bet as to whether information that enters a black hole ceases to exist -- that is, whether the interior of a black hole is changed at all by the characteristics of particles that enter it.
Hawking's research suggested that the particles have no effect whatsoever. But his theory violated the laws of quantum mechanics and created a contradiction known as the "information paradox."
Now physicists at Ohio State University have proposed a solution using string theory, a theory which holds that all particles in the universe are made of tiny vibrating strings.
Samir Mathur and his colleagues have derived an extensive set of equations that strongly suggest that the information continues to exist -- bound up in a giant tangle of strings that fills a black hole from its core to its surface.
The finding suggests that black holes are not smooth, featureless entities as scientists have long thought.
Instead, they are stringy "fuzzballs."
Mathur, professor of physics at Ohio State, suspects that Hawking and Thorne won?t be particularly surprised by the outcome of the study, which appears in the March 1 issue of the journal Nuclear Physics B.
In their wager, Hawking, professor of mathematics at the University of Cambridge, and Thorne, professor of theoretical physics at Caltech, bet that information that enters a black hole is destroyed, while Preskill -- also a professor of theoretical physics at Caltech -- took the opposite view. The stakes were a set of encyclopedias.
"I think that most people gave up on the idea that information was destroyed once the idea of string theory rose to prominence in 1995, Mathur said. "It?s just that nobody has been able to prove that the information survives before now."
In the classical model of how black holes form, a supermassive object, such as a giant star, collapses to form a very small point of infinite gravity, called a singularity. A special region in space surrounds the singularity, and any object that crosses the region?s border, known as the event horizon, is pulled into the black hole, never to return.
In theory, not even light can escape from a black hole.
The diameter of the event horizon depends on the mass of the object that formed it. For instance, if the sun collapsed into a singularity, its event horizon would measure approximately 3 kilometers (1.9 miles) across. If Earth followed suit, its event horizon would only measure 1 centimeter (0.4 inches).
As to what lies in the region between a singularity and its event horizon, physicists have always drawn a blank, literally. No matter what type of material formed the singularity, the area inside the event horizon was supposed to be devoid of any structure or measurable characteristics.
And therein lies the problem.
"The problem with the classical theory is that you could use any combination of particles to make the black hole -- protons, electrons, stars, planets, whatever -- and it would make no difference. There must be billions of ways to make a black hole, yet with the classical model the final state of the system is always the same," Mathur said.
That kind of uniformity violates the quantum mechanical law of reversibility, he explained. Physicists must be able to trace the end product of any process, including the process that makes a black hole, back to the conditions that created it.
If all black holes are the same, then no black hole can be traced back to its unique beginning, and any information about the particles that created it is lost forever at the moment the hole forms.
"Nobody really believes that now, but nobody could ever find anything wrong with the classical argument, either," Mathur said. "We can now propose what went wrong."
In 2000, string theorists named the information paradox number eight on their top-ten list of physics problems to be solved during the next millennium. That list included questions such as "what is the lifetime of a proton?" and "how can quantum gravity help explain the origin of the universe?"
Mathur began working on the information paradox when he was an assistant professor at the Massachusetts Institute of Technology, and he attacked the problem full time after joining the Ohio State faculty in 2000.
With postdoctoral researcher Oleg Lunin, Mathur computed the structure of objects that lie in-between simple string states and large classical black holes. Instead of being tiny objects, they turned out to be large. Recently, he and two doctoral students -- Ashish Saxena and Yogesh Srivastava -- found that the same picture of a "fuzzball" continued to hold true for objects more closely resembling a classic black hole. Those new results appear in Nuclear Physics B.
According to string theory, all the fundamental particles of the universe -- protons, neutrons, and electrons -- are made of different combinations of strings. But as tiny as strings are, Mathur believes they can form large black holes through a phenomenon called fractional tension.
Strings are stretchable, he said, but each carries a certain amount of tension, as does a guitar string. With fractional tension, the tension decreases as the string gets longer.
Just as a long guitar string is easier to pluck than a short guitar string, a long strand of quantum mechanical strings joined together is easier to stretch than a single string, Mathur said.
So when a great many strings join together, as they would in order to form the many particles necessary for a very massive object like a black hole, the combined ball of string is very stretchy, and expands to a wide diameter.
When the Ohio State physicists derived their formula for the diameter of a fuzzy black hole made of strings, they found that it matched the diameter of the black hole event horizon suggested by the classical model.
Since Mathur?s conjecture suggests that strings continue to exist inside the black hole, and the nature of the strings depends on the particles that made up the original source material, then each black hole is as unique as are the stars, planets, or galaxy that formed it. The strings from any subsequent material that enters the black hole would remain traceable as well.
That means a black hole can be traced back to its original conditions, and information survives.
|Illustration of Black Hole with Accretion Disk and Torus. An artist's conception shows a black hole surrounded by a disk of hot gas, and a large doughnut or torus of cooler gas and dust. The light blue ring on the back of the torus is due to the fluorescence of iron atoms excited by X-rays from the hot gas disk.
(Illustration: CXC/M.Weiss) Source: http://chandra.harvard.edu/resources/illustrations/blackholes.html.
This explains the whining I hear allll dayyyyy looooong.
Instead, they are stringy "fuzzballs."
Gee I got a couple of them things out in my garage. Think they might be dangerous????
Outlaw fuzzballs and only criminals will have fuzzballs.
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Flowing waters in streams, tidal channels, and underground channels develop intense concentrations of life which make use of the physical stirring energy and draw resources from the moving waters. The living and nonliving components of the climax ecosystem are either continually renewed by the inflow or have means for staying in position. Flowing waters are dominated by eddies and currents, and have a high rate of water turnover. Lotic environments, as they are sometimes called, often have more high-quality energy available than standing waters. Often a flowing ecosystem has a current-dependent reef or encrusting surface subsystem (Chapter 14). Where light is available, characteristic mats of algal cells and associated microzoa develop. These are called periphyton or aufwuchs.
KeywordsCurrent Velocity Algal Cell Stream Ecosystem Periphyton Biomass Artificial Stream
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A waterspout is an intense columnar vortex (usually appearing as a funnel-shaped cloud) that occurs over a body of water. Some are connected to a cumulus congestus cloud, some to a cumuliform cloud and some to a cumulonimbus cloud. In the common form, it is a non-supercell tornado over water.
While it is often weaker than most of its land counterparts, stronger versions spawned by mesocyclones do occur. Most waterspouts do not suck up water; they are small and weak rotating columns of air over water.
While waterspouts form mostly in the tropics and subtropical areas, other areas also report waterspouts, including Europe, Australia, New Zealand, the Great Lakes, Antarctica and on rare occasions, the Great Salt Lake. Although rare, waterspouts have been observed in connection with lake-effect snow precipitation bands.
Waterspouts have a five-part life cycle: formation of a dark spot on the water surface, spiral pattern on the water surface, formation of a spray ring, development of the visible condensation funnel, and ultimately decay.
- 1 Formation
- 2 Types
- 3 Climatology
- 4 Life cycle
- 5 Marine hazard
- 6 Threat to marine animals
- 7 Research and forecasting
- 8 Myths and legends
- 9 See also
- 10 References
- 11 External links
Waterspouts exist on a microscale, where their environment is less than two kilometers in width. The cloud from which they develop can be as innocuous as a moderate cumulus, or as great as a supercell. While some waterspouts are strong and tornadic in nature, most are much weaker and caused by different atmospheric dynamics. They normally develop in moisture-laden environments as their parent clouds are in the process of development, and it is theorized they spin as they move up the surface boundary from the horizontal shear near the surface, and then stretch upwards to the cloud once the low level shear vortex aligns with a developing cumulus cloud or thunderstorm. Weak tornadoes, known as landspouts, have been shown to develop in a similar manner.
Waterspouts that are not associated with a rotating updraft of a supercell thunderstorm are known as "non-tornadic" or "fair-weather waterspouts", and are by far the most common type. Fair-weather waterspouts occur in coastal waters and are associated with dark, flat-bottomed, developing convective cumulus towers. Waterspouts of this type rapidly develop and dissipate, having life cycles shorter than 20 minutes. They usually rate no higher than EF0 on the Enhanced Fujita scale, generally exhibiting winds of less than 30 m/s (67 mph; 108 km/h).
They are most frequently seen in tropical and sub-tropical climates, with upwards of 400 per year observed in the Florida Keys. They typically move slowly, if at all, since the cloud to which they are attached is horizontally static, being formed by vertical convective action instead of the subduction/adduction interaction between colliding fronts. Fair-weather waterspouts are very similar in both appearance and mechanics to landspouts, and largely behave as such if they move ashore.
"Tornadic waterspouts", also accurately referred to as "tornadoes over water", are formed from mesocyclonic action in a manner essentially identical to land-based tornadoes in connection with severe thunderstorms, but simply occurring over water. A tornado which travels from land to a body of water would also be considered a tornadic waterspout. Since the vast majority of mesocyclonic thunderstorms occur in land-locked areas of the United States, true tornadic waterspouts are correspondingly rarer than their fair-weather counterparts in that country. However, in some areas, such as the Adriatic, Aegean and Ionian seas, tornadic waterspouts can make up half of the total number.
A winter waterspout, also known as a snow devil, an icespout, an ice devil, a snownado, or a snowspout, is an extremely rare instance of a waterspout forming under the base of a snow squall. The term "winter waterspout" is used to differentiate between the common warm season waterspout and this rare winter season event. Very little is known about this phenomenon and only six known pictures of this event exist to date, four of which were taken in Ontario, Canada. There are a couple of critical criteria for the formation of a winter waterspout. Very cold temperatures need to be present over a body of water warm enough to produce fog resembling steam above the water's surface. Like the more efficient lake-effect snow events, winds focusing down the axis of long lakes enhance wind convergence and likely enhance their development.
Though the majority of waterspouts occur in the tropics, they can seasonally appear in temperate areas throughout the world, and are common across the western coast of Europe as well as the British Isles and several areas of the Mediterranean and Baltic Sea. They are not restricted to saltwater; many have been reported on lakes and rivers including the Great Lakes and the St. Lawrence River. Waterspouts are fairly common on the Great Lakes during late summer and early fall, with a record 66+ waterspouts reported over just a seven-day period in 2003. They are more frequent within 100 kilometers (60 mi) from the coast than farther out at sea. Waterspouts are common along the southeast U.S. coast, especially off southern Florida and the Keys and can happen over seas, bays, and lakes worldwide. Approximately 160 waterspouts are currently reported per year across Europe, with the Netherlands reporting the most at 60, followed by Spain and Italy at 25, and the United Kingdom at 15. They are most common in late summer. In the Northern Hemisphere, September has been pinpointed as the prime month of formation. Waterspouts are frequently observed off the east coast of Australia, with several being described by Joseph Banks during the voyage of the Endeavour in 1770.
There are five stages to the waterspout life cycle. Initially, a prominent circular, light-colored disk appears on the surface of the water, surrounded by a larger dark area of indeterminate shape. After the formation of these colored disks on the water, a pattern of light and dark-colored spiral bands develop from the dark spot on the water surface. Then, a dense annulus of sea spray, called a cascade, appears around the dark spot with what appears to be an eye. Eventually, the waterspout becomes a visible funnel from the water surface to the overhead cloud. The spray vortex can rise to a height of several hundred feet or more and often creates a visible wake and an associated wave train as it moves. Eventually, the funnel and spray vortex begin to dissipate as the inflow of warm air into the vortex weakens, ending the waterspout's life cycle.
Waterspouts have long been recognized as serious marine hazards. Stronger waterspouts pose threats to watercraft, aircraft and people. It is recommended to keep a considerable distance from these phenomena, and to always be on alert through weather reports. The United States National Weather Service will often issue special marine warnings when waterspouts are likely or have been sighted over coastal waters, or tornado warnings when waterspouts are expected to move onshore.
Incidents of waterspouts causing severe damage and casualties are rare. However, there have been several notable examples. The Malta tornado in 1555 was the earliest record of a deadly waterspout. It struck the Grand Harbour of Valletta, sinking four galleys, numerous boats, and claiming hundreds of lives. The 1851 Sicily Tornadoes were twin waterspouts that made landfall in western Sicily, ravaging the coast and countryside before ultimately dissipating back again over the sea. A waterspout has been proposed as a possible reason for the inexplicable abandonment of the Mary Celeste.
Threat to marine animals
Depending on how fast the winds from a waterspout are whipping, anything that is within about one yard of the surface of the water, including fish of different sizes, frogs, and even turtles, can be lifted into the air. A waterspout can sometimes suck small animals such as fish out of the water and all the way up into the cloud. Even if the waterspout stops spinning, the fish in the cloud can be carried over land, buffeted up and down and around with the cloud’s winds until its currents no longer keep the flying fish in the atmosphere. Depending on how far they travel and how high they are taken into the atmosphere, the fish are sometimes dead by the time they rain down. People as far as 100 miles (160 km) inland have experienced raining fish. Fish can also be sucked up from rivers, but raining fish is not a common weather phenomenon.
Research and forecasting
Szilagyi Waterspout Index (SWI)
The Szilagyi Waterspout Index (SWI), developed by Canadian meteorologist Wade Szilagyi, is used to predict conditions favorable for waterspout development. The SWI ranges from −10 to +10, where values greater than or equal to zero represent conditions favorable for waterspout development.
International Centre for Waterspout Research (ICWR)
The ICWR is a non governmental organization of individuals from around the world who are interested in the field of waterspouts from a research, operational and safety perspective. Originally a forum for researchers and meteorologists, the ICWR has expanded interest and contribution from storm chasers, the media, the marine and aviation communities and from private individuals.
Myths and legends
There was a commonly-held belief among sailors in the 18th and 19th centuries that shooting a broadside cannon volley dispersed waterspouts. Amongst others, Captain Vladimir Bronevskiy claims that it was a successful technique, being an eye-witness to the dissipation of a phenomena in the Adriatic while being a midshipman aboard the frigate Venus during the 1806 campaign under Admiral Senyavin.
|Wikimedia Commons has media related to Waterspouts.|
- "Waterspout definition". A Comprehensive Glossary Of Weather. Geographic.org. Retrieved 2014-07-10.
- What Is a Waterspout? (Weather Channel video)
- Waterspout comes ashore in Galveston by Jessica Hamilton, Houston Chronicle, July 17, 2016
- Answer.com (ed.). "Waterspout". McGraw-Hill Encyclopedia of Science and Technology. Retrieved 6 December 2010.
- Keith C. Heidorn. Islandnet.com, ed. "Water Twisters". The Weather Doctor Almanach. Retrieved 6 December 2010.
- Schwiesow, R.L.; Cupp, R.E.; Sinclair, P.C.; Abbey, R.F. (April 1981). "Waterspout Velocity Measurements by Airborne Doppler Lidar". Journal of Applied Meteorology. 20: 341–348. Bibcode:1981JApMe..20..341S. doi:10.1175/1520-0450(1981)020<0341:WVMBAD>2.0.CO;2. Retrieved 11 August 2013.
- "Several waterspouts filmed on Lake Michigan in US". BBC News. 20 August 2012. Retrieved 20 August 2012.
- Taylor, Stanley. "Antarctic Diary". Retrieved 4 June 2013.
- publisher=journals.ametsoc.org| url=journals.ametsoc.org/doi/pdf/10.1175/1520-0493-119-12-2740.1|author=J Simpson |date=1991
- Choy, Barry K.; Scott M. Spratt. "Using the WSR-88D to Predict East Central Florida Waterspouts". National Oceanic and Atmospheric Administration. Archived from the original on 5 October 2006. Retrieved 25 October 2006.
- National Weather Service Forecast Office, Milwaukee/Sullivan, WI (30 April 2008). "Threat Definitions for Waterspouts". National Weather Service Central Region Headuqaters. Retrieved 27 August 2009.
- National Weather Service in Key West, Florida (12 September 2002). "Waterspouts". Basic Spotter Training Version 1.2. NOAA. pp. 4–24. Archived from the original on 9 October 2007. Retrieved 21 July 2008.
- Bruce B. Smith (22 February 2007). "Waterspouts". National Weather Service Central Region Headquarters. Retrieved 21 June 2009.
- National Weather Service Forecast Office, Melbourne, Florida (25 January 2007). "Graphical Hazardous Weather Outlook: Waterspout Threat". Southern Region Headquarters. Archived from the original on 19 December 2005. Retrieved 21 June 2009.
- Waylon G. Collins; Charles H. Paxton; Joseph H. Golden (February 2000). "The 12 July 1995 Pinellas County, Florida, Tornado/Waterspout". Weather and Forecasting, vol. 15, issue 1. pp. 122–134. Retrieved 21 June 2009.
- Michalis V. Sioutasa & Alexander G. Keul (February 2007). "Waterspouts of the Adriatic, Ionian and Aegean Sea and their meteorological environment". Journal of Atmospheric Research, vol. 83, issues 2–4: 542–557. Bibcode:2007AtmRe..83..542S. doi:10.1016/j.atmosres.2005.08.009.
- The Buffalo News (14 April 2003). "Waterspouts". State University of New York in Buffalo. Retrieved 21 July 2008.
- The Weather Channel (2008). "Snow Devil". Glossary. Archived from the original on 1 August 2008. Retrieved 21 July 2008.
- National Weather Service Forecast Office, Burlington, Vermont (3 February 2009). "15 January 2009: Lake Champlain Sea Smoke, Steam Devils, and Waterspout: Chapters IV and V". Eastern Region Headquarters. Retrieved 21 June 2009.
- Canadian Television News Staff (23 July 2008). "Rare waterspout forms in Montreal during storm". Retrieved 21 June 2009.
- National Oceanic and Atmospheric Administration (4 December 2009). "The Great Waterspout Outbreak of 2003". Retrieved 6 August 2009.
- Wade Szilagyi from the Meteorological Service of Canada (December 2004). "The Great Waterspout Outbreak of 2003". Mariner's Weather Log. NOAA. 43 (3). Retrieved 25 October 2006.
- Gibson, Jano (14 June 2007). "Waterspout off Sydney". The Sydney Morning Herald. Retrieved 23 January 2010.
- "Water spout touches down off Sydney beaches". Daily Telegraph. 8 July 2008. Retrieved 23 January 2010.
- Banks, Joseph (1997). The Endeavour Journal of Sir Joseph Banks, 1768–1771. University of Sydney Library.
- Auslan Cramb (7 August 2003). "Water Spout Hit Helicopter". The Telegraph. Retrieved 21 June 2009.
- National Weather Service Forecast office, Melbourne, Florida (25 January 2007). "Graphical Hazardous Weather Outlook: Waterspout Threat". Southern Region Headquarters. Archived from the original on 1 October 2006. Retrieved 21 June 2009.
- Abela, Joe. "Claude de la Sengle (1494 - 1557)". Senglea Local Council. Retrieved 11 November 2015.
- Susan Cosier (17 September 2006). "It's Raining Fish: Unusual objects sometimes fall from the sky, courtesy of waterspouts". Scienceline (Physical Science). NYU Journalism. Retrieved 17 May 2015.
- Szilagyi, Wade (12–16 October 2009). "A Waterspout Forecasting Technique" (pdf). Pre-prints. 5h European Conference on Severe Storms. Landshut – GERMANY. pp. 129–130.
- Sioutas Michalis, Szilagyi Wade & Κeul Alexander (2013). "Waterspout Outbreaks over areas of Europe and North America: Environments and Predictability". Atmospheric Research. 123: 167–179. Bibcode:2013AtmRe.123..167S. doi:10.1016/j.atmosres.2012.09.013.
- "The International Centre For Waterspout Research". Retrieved 10 December 2011.
- The Universal Magazine of Knowledge and Pleasure. 6 and 7. 1750. p. 154.
- American Journal of Science and Arts. S. Converse. 1849. p. 266.
- Robert Johnson (1810). The Adventures of Captain Robert Johnson. Thomas Tegg. p. B2.
- Naval Memoirs of Vladimir Brovevskiy (in Russian). Тип. Императорской Росс. Акад. 1837. p. 322.
- A series of pictures from the boat Nicorette approaching the NSW south coast tornadic waterspout.
- A USA Today online article on waterspouts: https://www.usatoday.com/weather/wspouts.htm
- Online waterspout article
- Pictures of cold-core waterspouts over Lake Michigan on 30 September 2006. Archived from the original on 10 March 2007.
- Large waterspout off southern Tongatapu, February 2014
- Experimental Great Lakes Forecast
- Winter waterspout | <urn:uuid:d4181548-6bfc-4456-a623-12b5bb241cfd> | 4 | 3,694 | Knowledge Article | Science & Tech. | 53.127909 | 95,515,534 |
Quantum physics is weird. As soon as you think you understand it, you find five more reasons you don't. Take this, for example: the Standard Model of quantum physics says that everything is made up of elementary particles, including things like quarks, electrons, and protons. But string theory says nope, not quite. All of these different particles? They're just strings, each vibrating in their own way. That might sound like it adds unnecessary complexity, but it could solve a problem that has plagued quantum physics for decades.
Small Quantum Particles Tied up With String
10 Dimensions of Space on the Wall
String Theory Membranes and the Multiverse
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Written by Ashley Hamer April 12, 2017 / Updated: February 9, 2018
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In case you’ve haven’t heard, N.A.S.A (National Aeronautics and Space Administration) will be receiving a much larger budget in the upcoming fiscal year. For the year 2015, N.A.S.A.’s budget was around $18.01 billion, while for 2016 it’s going to be around $19.3 billion, which is $1.27 billion more than the budget President Obama initially proposed.
So the question here quickly becomes: what’s the reason for the increased funds? Is there going to be a new wave of space exploration? And if so, is the colonization of other planets being explored?
Well, according to Universe Today, pretty much all of N.A.S.A.’s programs will benefit from the extra money. However, there is one big winner that I would like to cover: the ‘Journey to Mars’ initiative. Note, this initiative is not a sole program. Rather it is a combination of several programs, such as the Space Launch System (SLS), and the Orion crew capsule.
The SLS is getting $2 billion of the new budget. This is the rocket platform that will eventually send people to planets like Mars for colonization. When completed it is expected to be the biggest rocket ever built. Manned missions using this rocket are currently slated for some time in the 2030’s, with unmanned tests starting in late 2018.
The other big winner, the Orion Space Capsule, will also receive $1.27 billion of the new budget. When the SLS launches, it will have this capsule situated on top, much like the Apollo missions. The new capsule is designed for a four man crew, and can carry out
Overall, however, the real beneficiary of the increased NASA budget is the world, at least in the long term. It seems that over the past decade, the one thing that seems to unite different countries and cultures is scientific research and the practical projects associated with space exploration. Even now with the political tension between the U.S. and Russia extremely worrying, we still see cooperation in transporting personnel and supplies to and from the International Space Station. In this one area, there is no lack of support and interest from most developed nations, with space projects even able to inspire cooperation between historical enemies.
I for one can’t wait to see how these programs develop. While many of us will likely be too old to participate once they boldly start sending people off to colonize the final frontier, I do think, however, that colonizing other worlds will help much of the world’s nations to realize that cooperation is the only viable long term international relationship worth developing. | <urn:uuid:660f81df-5a48-462e-ab98-19c66a5f8bc3> | 2.78125 | 563 | Personal Blog | Science & Tech. | 60.311016 | 95,515,557 |
A programming language designed for robustness, optimality, and clarity.
- Small, simple language. Focus on debugging your application rather than debugging knowledge of your programming language.
- Ships with a build system that obviates the need for a configure script or a makefile. In fact, existing C and C++ projects may choose to depend on Zig instead of e.g. cmake.
- A fresh take on error handling which makes writing correct code easier than writing buggy code.
- Debug mode optimizes for fast compilation time and crashing with a stack trace when undefined behavior would happen.
- ReleaseFast mode produces heavily optimized code. What other projects call "Link Time Optimization" Zig does automatically.
- Compatible with C libraries with no wrapper necessary. Directly include C .h files and get access to the functions and symbols therein.
- Provides standard library which competes with the C standard library and is always compiled against statically in source form. Compile units do not depend on libc unless explicitly linked.
- Nullable type instead of null pointers.
- Safe unions, tagged unions, and C ABI compatible unions.
- Generics so that one can write efficient data structures that work for any data type.
- No header files required. Top level declarations are entirely order-independent.
- Compile-time code execution. Compile-time reflection.
- Partial compile-time function evaluation with eliminates the need for a preprocessor or macros.
- The binaries produced by Zig have complete debugging information so you can, for example, use GDB or MSVC to debug your software.
- Built-in unit tests with
- Friendly toward package maintainers. Reproducible build, bootstrapping process carefully documented. Issues filed by package maintainers are considered especially important.
- Cross-compiling is a primary use case.
- In addition to creating executables, creating a C library is a primary use case. You can export an auto-generated .h file.
Freestanding means that you do not directly interact with the OS or you are writing your own OS.
Note that if you use libc or other libraries to interact with the OS, that counts as "freestanding" for the purposes of this table.
Wanted: Windows Developers
Flesh out the standard library for Windows, streamline Zig installation and distribution for Windows. Work with LLVM and LLD teams to improve PDB/CodeView/MSVC debugging. Implement stack traces for Windows in the MinGW environment and the MSVC environment.
Wanted: MacOS and iOS Developers
Flesh out the standard library for MacOS. Improve the MACH-O linker. Implement stack traces for MacOS. Streamline the process of using Zig to build for iOS.
Wanted: Android Developers
Flesh out the standard library for Android. Streamline the process of using Zig to build for Android and for depending on Zig code on Android.
Wanted: Web Developers
Figure out what are the use cases for compiling Zig to WebAssembly. Create demo projects with it and streamline experience for users trying to output WebAssembly. Work on the documentation generator outputting useful searchable html documentation. Create Zig modules for common web tasks such as WebSockets and gzip.
Wanted: Embedded Developers
Flesh out the standard library for uncommon CPU architectures and OS targets. Drive issue discussion for cross compiling and using Zig in constrained or unusual environments.
Wanted: Game Developers
Create cross platform Zig modules to compete with SDL and GLFW. Create an OpenGL library that does not depend on libc. Drive the usability of Zig for video games. Create a general purpose allocator that does not depend on libc. Create demo games using Zig.
Stage 1: Build Zig from C++ Source Code
- cmake >= 2.8.5
- gcc >= 5.0.0 or clang >= 3.6.0
- LLVM, Clang, LLD development libraries == 6.x, compiled with the same gcc or clang version above
- These depend on zlib and libxml2.
- cmake >= 2.8.5
- Microsoft Visual Studio 2015
- LLVM, Clang, LLD development libraries == 6.x, compiled with the same MSVC version above
mkdir build cd build cmake .. make make install bin/zig build --build-file ../build.zig test
brew install cmake llvm@6 brew outdated llvm@6 || brew upgrade llvm@6 mkdir build cd build cmake .. -DCMAKE_PREFIX_PATH=/usr/local/opt/llvm@6/ make install bin/zig build --build-file ../build.zig test
Stage 2: Build Self-Hosted Zig from Zig Source Code
Note: Stage 2 compiler is not complete. Beta users of Zig should use the Stage 1 compiler for now.
Dependencies are the same as Stage 1, except now you have a working zig compiler.
bin/zig build --build-file ../build.zig --prefix $(pwd)/stage2 install
./stage2/bin/zig which can be used for testing and development.
Once it is feature complete, it will be used to build stage 3 - the final compiler
Stage 3: Rebuild Self-Hosted Zig Using the Self-Hosted Compiler
This is the actual compiler binary that we will install to the system.
Note: Stage 2 compiler is not yet able to build Stage 3. Building Stage 3 is not yet supported.
Debug / Development Build
./stage2/bin/zig build --build-file ../build.zig --prefix $(pwd)/stage3 install
Release / Install Build
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+44 1803 865913
By: Alessandro Minelli
406 pages, 11 line illus
A critical overview of the state-of-the-art in biological systematics, that presents a broad perspective of the subject covering its history, theory and practice. Includes a major review of the current state of taxonomy and a discussion of evolutionary patterns.
Part 1 Problems and methods: systems and classifications; some steps in comparative biology; biochemical and molecular systematics; the species; resources and media. Part 2 The state of the art: the inventory of natural diversity; towards the system; interviews on the daily work of systematists - problems and trends; the unequal distribution of taxonomic diversity; domesticated and cultivated plants. Part 3 Epilogue: some dangerous trends and a hope for the future.
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Will the UK Floods Return in 2017?
Aug 04 2017 Read 1214 Times
There is a high risk that the excessive rainfall which plagued the UK in the winter of 2013/14, and then again in 2015/16, could return in the coming winters. According to a new study conducted by the UK Met Office, there’s a 7% chance that rainfall records could be broken in the south east of England.
Even more concerning, there’s also a one-in-three chance that records could be broken in at least one region across England and Wales every year for the next decade, and that they could be surpassed by as much as 30%.
The UNSEEN approach
The Met Office reached its findings through a sophisticated analysis of complex environmental matrices. Specifically, the team collated data from the years 1981 to 2015 and ran it through their resident supercomputer hundreds of times. From these simulations, they were able to note that several regions of the UK showed a higher incidence of similar rainfall as experienced in years of flooding.
The approach has been nicknamed UNSEEN research, since it estimates the likelihood of events that have not yet come to pass. It was used before when the Met Office was asked to compile a National Flood Resilience Review (NFRR) in order to test the effectiveness of UK flood defences. However, critics have claimed that the NFRR did not go far enough, since it neglected to take surface flooding into account when calculating its research.
“It should be an urgent priority for the Environment Secretary to re-open the National Flood Resilience Review with the aim of improving the UK's preparedness against surface water flooding caused by heavy rainfall, the risks of which are clearly spelled out in this paper,” stressed Bob Ward, a researcher at the Grantham Research Institute on Climate Change.
Climate change the culprit?
The research showed that there was a 34% chance of records being broken in the coming years in at least one region of the UK, leading to fears that we could experience similar flooding as in recent winters. What’s more, it’s thought that those records could be broken by as much as 30%.
“That is an enormous number, to have a monthly value that's 30% larger, it's a bit like what we had in 2014, and as much again,” said Professor Adam Scaife from the Met Office. “We are not attributing this directly to climate change, what we are saying is that if you take in everything that's in the climate system today then that is the risk. Climate change is already happening and we've already got some and that is folded in here.”
Regardless of whether climate change is to blame, it’s to be hoped that we have learned from the recent extreme flooding of years gone by and have improved our defences to such a standard that will withstand the rainfall, records or not.
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Mystery as 'highly unusual' radioactive substance enriched with the type of uranium used to make nuclear fuel and bombs is detected in Alaska
- Experts detected the particles 4.3 miles (7 km) above the Aleutian Islands
- The aerosol was measured by a Nasa WB-57 high altitude research plane
- This is the first time in 20 years of these missions uranium-235 has been found
- The radioactive sample may have originated in China, Japan or North Korea
Particles enriched with uranium, used to make nuclear fuel and bombs, have been detected above Alaska - and their source remains a mystery.
The 'highly unusual' particles, containing the isotope uranium-235, were spotted in the atmosphere for the first time in 20 years of plane-based atmospheric observations.
Experts have discounted natural causes, although research suggests it originated in Asia.
Scroll down for video
Particles enriched with uranium, used to make nuclear fuel and bombs, have been detected above Alaska in a world first. The atmospheric aerosol was measured by a Nasa WB-57 plane (pictured) used in high altitude research (stock image)
Scientists from the US National Oceanic and Atmospheric Administration (NOAA) detected the particles at an altitude of 4.3 miles (seven km) above Alaska's Aleutian Islands.
The atmospheric aerosol was measured by a Nasa WB-57 plane, used in high altitude research.
Uranium, the heaviest element to occur naturally on the planet, comes in the form of the slightly radioactive isotope uranium-238.
A 'highly unusual aerosol particle containing a very small amount of enriched uranium' was tracked above Alaska's Aleutian Islands. Experts believe that the sample may have come from China , Japan or North Korea
Trace amounts of uranium-235, specifically used for making nuclear fuel and bombs, do also occur naturally.
During millions of research missions using planes to capture atmospheric particles, experts have never before obtained a sample containing uranium-235.
Writing in a study on the finding, its authors said: 'The purpose of the field campaign was to obtain some of the first global cross-sections of the concentration of trace gases and of dust, smoke, and other particles in the remote troposphere over the Pacific and Atlantic Oceans.
'Analysis of wind trajectories and particle dispersion model results show that the particle could have originated from a variety of areas across Asia.'
Researchers believe the sample came from recently created reactor-grade uranium, perhaps from burnt nuclear fuel.
This rules out nuclear disasters like Chernobyl and Fukushima.
Dan Murphy, who led the study, oversees flights across the globe which sample the atmosphere for aerosols.
During millions of research missions using planes to capture atmospheric particles, experts have never before obtained a sample containing uranium-235. Experts believe it came from recently created reactor-grade uranium, perhaps from burnt nuclear fuel (stock)
The tiny particles originate from fires, pollution, dust and other sources and can affect cloud formation and weather patterns.
Speaking to Gizmodo, Mr Murphy added: 'It's not a significant amount of radioactive debris by itself.
'But it's the implication that there's some very small source of uranium that we don't understand.
'One of the main motivations of this paper is to see if somebody who knows more about uranium than any of us would understand the source of the particle.'
The full findings were published in the Journal of Environmental Radioactivity.
WHAT IS URANIUM-235?
There are a two main types of Uranium that are found in nature: Uranium-235 and Uranium-238.
Called isotopes, these varieties of the same element have a different amount of neutrons in the nucleus of the atoms.
More than 99 per cent of all Uranium found on Earth is Uranium 238, which is relatively harmless and stable.
Around 0.7 per cent of the Uranium on Earth is Uranium-235 which is radioactive and can sustain nuclear fission reactions (fissile).
Uranium-235 (U-235) is the only fissile radioactive isotope which exists in nature in its standard form.
The ability to fuel nuclear reactions comes from the fact that it naturally decays into Thorium and one alpha particle.
Once this reaction happens, a large unstoppable chain reaction occurs that releases vast amounts of alpha radiation.
Alpha radiation is seriously damaging to organic material and can cause mutations that can lead to cancer.
Although it is extremely damaging if in contact with organic material, it is so large that it struggles to travel through the air and can be stopped by a piece of paper.
Uranium-235 is also used in nuclear power plants. Here, the atoms of U-235 are split by high-speed neutrons.
Splitting a kilogram of U-235 releases a huge amount of energy - about 2.5 million times the amount of energy produced by burning the same amount of coal.
Uranium-235 was used in the 'little boy' bomb dropped on Hiroshima on August 6, 1945 which was made of highly-enriched Uranium.
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A University of Missouri study published in Nature this week has found that the Earth's crust melts easier than previously thought.
In the study, researchers measured how well rocks conduct heat at different temperatures and found that as rocks get hotter in the Earth's crust, they become better insulators and poorer conductors. This finding provides insight into how magmas are formed and will lead to better models of continental collision and the formation of mountain belts.
"In the presence of external heat sources, rocks will heat up more efficiently than previously thought," said Alan Whittington, professor of geological sciences in the MU College of Arts and Science. "We applied our findings to computer models that predict what happens to rocks when they get buried and heat up in mountain belts, such as the Himalayas today or the Black Hills in South Dakota in the geologic past. We found that strain heating, caused by tectonic movements during mountain belt formation, quite easily triggers crustal melting."
The study, "Temperature-dependent thermal diffusivity of the Earth's crust and implications for magmatism," was published in this week's Nature and was co-authored by Whittington, Nabelek and Anne Hofmeister, a professor at Washington University. The National Science Foundation funded this research.
Kelsey Jackson | EurekAlert!
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Original Research ARTICLE
Combined Effects of Experimental Acidification and Eutrophication on Reef Sponge Bioerosion Rates
- 1Department of Ocean Systems, NIOZ Royal Netherlands Institute for Sea Research and Utrecht University, Texel, Netherlands
- 2Department of Marine Microbiology and Biogeochemistry, NIOZ Royal Netherlands Institute for Sea Research and Utrecht University, Texel, Netherlands
- 3Department of Ocean Systems, NIOZ Royal Netherlands Institute for Sea Research, Texel, Netherlands
- 4Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Utrecht, Netherlands
Health of tropical coral reefs depends largely on the balance between constructive (calcification and cementation) and destructive forces (mechanical-chemical degradation). Gradual increase in dissolved CO2 and the resulting decrease in carbonate ion concentration (“ocean acidification”) in ocean surface water may tip the balance toward net mass loss for many reefs. Enhanced nutrients and organic loading in surface waters (“eutrophication”), may increase the susceptibility of coral reef and near shore environments to ocean acidification. The impacts of these processes on coral calcification have been repeatedly reported, however the synergetic effects on bioerosion rates by sponges are poorly studied. Erosion by excavating sponges is achieved by a combination of chemical dissolution and mechanical chip removal. In this study, Cliona caribbaea, a photosymbiont-bearing excavating sponge widely distributed in Caribbean reef habitats, was exposed to a range of CO2 concentrations, as well as different eutrophication levels. Total bioerosion rates, estimated from changes in buoyant weights over 1 week, increased significantly with pCO2 but not with eutrophication. Observed chemical bioerosion rates were positively affected by both pCO2 and eutrophication but no interaction was revealed. Net photosynthetic activity was enhanced with rising pCO2 but not with increasing eutrophication levels. These results indicate that an increase in organic matter and nutrient renders sponge bioerosion less dependent on autotrophic products. At low and ambient pCO2, day-time chemical rates were ~50% higher than those observed at night-time. A switch was observed in bioerosion under higher pCO2 levels, with night-time chemical bioerosion rates becoming comparable or even higher than day-time rates. We suggest that the difference in rates between day and night at low and ambient pCO2 indicates that the benefit of acquired energy from photosynthetic activity surpasses the positive effect of increased pCO2 levels at night due to holobiont respiration. This implies that excavation must cost cellular energy, by processes, such as ATP usage for active Ca2+ and/or active proton pumping. Additionally, competition for dissolved inorganic carbon species may occur between bioerosion and photosynthetic activity by the symbionts. Either way, the observed changing role of symbionts in bioerosion can be attributed to enhanced photosynthetic activity at high pCO2 levels.
The ocean serves as the largest sink of anthropogenic CO2 on earth after the atmosphere itself. Since the beginning of the industrial revolution, it has taken up ~28% of the emitted anthropogenic CO2 (Le Quéré et al., 2015). The cumulative uptake of atmospheric carbon dioxide by the ocean has increased the total marine inorganic carbon concentration, reduced pH and consequently decreased the CaCO3 saturation state. Together, these effects are termed ocean acidification (OA) and it is predicted that average surface ocean CaCO3 saturation state will have decreased by 25–50% at the end of the current century, depending on the emission scenario (Hoegh-Guldberg et al., 2007; Gattuso and Hansson, 2011; Veron, 2011; Le Quéré et al., 2013).
Eutrophication, caused by increasing release of nutrients and organic material in surface waters, represents an additional threat to near-shore and coral reef environments. Recent studies have shown that local anthropogenic disturbances, such as nutrient and organic rich run-offs from agriculture and coastal development, as well as the input of poorly treated waste waters (Gast et al., 1999; Lapointe and Mallin, 2011; Govers et al., 2014) have caused the average pCO2 of coral reefs to increase ~3.5-fold faster throughout the globe over the past 20 years compared to the open ocean. This is suggested to be caused by a shift in the metabolic balance of coral reef ecosystems (Cai et al., 2011; Cyronak et al., 2014; Yeakel et al., 2015). Such anthropogenic input also promotes growth of opportunistic organisms, such as sponges, macroalgae, turf algae and/or benthic cyanobacteria (Holmes, 2000; Kuffner and Paul, 2001; Gorgula and Connell, 2004; Vermeij et al., 2010), potentially resulting also in major shifts in benthic community compositions (Hughes, 1994; Bruno et al., 2009; De Bakker et al., 2017).
Reef bioerosion by sponges and other bioeroding organisms (Wisshak and Tapanila, 2008) plays an important role in regulating the carbonate budget of coral reefs (Perry et al., 2014). Although the negative effects of OA on production of CaCO3 (calcification) by corals are widely documented (Gattuso et al., 1998; Kleypas and Langdon, 2006; Hoegh-Guldberg et al., 2007; Ries et al., 2009; Pandolfi et al., 2011; Dove et al., 2013), its impact on biologically induced carbonate dissolution and mechanical destruction have been understudied (Zundelevich et al., 2007; Fang et al., 2013a; Wisshak et al., 2014; Enochs et al., 2015; Schönberg et al., 2017) and has so far not been quantified in combination with eutrophication.
Bioeroding sponges contribute between 60 and 90% of total macroborer activity on coral reefs and their (surface-normalized) erosion rates have been found to equal and even surpass calcification rates of hermatypic corals (MacGeachy and Stearn, 1976; Hudson, 1977; Edinger et al., 2000; Carballo et al., 2008; Perry et al., 2014). Bioeroding sponges use a combination of chemical dissolution and mechanical CaCO3 chip removal to erode coral substrate (Nasonov, 1924; Rützler and Rieger, 1973; Pomponi, 1980). It is hypothesized that specialized cells of the bioeroding sponges are able to lower the pH at selected sites to promote controlled aragonite dissolution, thereby creating cavities in which the sponge grows. The mechanisms by which sponges dissolve carbonate has however remained elusive since this etching interface is not directly accessible. Several of the most competitive bioeroding sponges harbor endosymbiotic dinoflagellate zooxanthellae and this symbiosis has been shown to enhance bioerosion in light (Hill, 1996; Fang et al., 2016). This raises the question further as to how symbionts enhance bioerosion. Geochemically, this is paradoxical because the autotrophic symbionts would tend to increase pH and enhance carbonate precipitation rather than dissolution (Garcia-Pichel et al., 2010).
If the chemical composition of the fluid at these sites is related to that of seawater, a reduction in ambient saturation state may lower energetic costs for the sponge to create a micro-environment that is undersaturated for CaCO3, in which the aragonite skeleton may subsequently dissolve and chips are dislodged. Schönberg (2008) provided a first glimpse of a pH gradient toward the etching sites using micro-sensors which may indicate that sponges do indeed alter the chemistry at the site of bioerosion. Although the underlying physiological and mechanical processes employed by the sponges to erode are currently unknown, a number of studies have shown that an increase in pCO2 of the ambient water results in increased bioerosion rates (Wisshak et al., 2012, 2013; Duckworth and Peterson, 2013; Fang et al., 2013a), suggesting that changes in seawater chemistry directly affect the saturation state at the site where the coral aragonite is dissolved.
Since eutrophication may increase effects of OA in coastal waters, we here assess the potential combined effects on bioerosion rates (both chemical and mechanical) of the sponge Cliona caribbaea Carter, 1882. C. caribbaea is found abundantly in the Caribbean and is a representative of the “Cliona viridis species complex,” including clionaids that form a symbiosis with the dinoflagellates of the genus Symbiodinium (Schönberg, 2000). These photosynthetic symbionts (zooxanthellae) provide sponges with a significant fraction of their carbon and energy via photosynthesis (Weisz et al., 2010; Fang et al., 2014). Since this affects diurnal patterns in the holobiont metabolism (Freeman and Thacker, 2011), bioerosion rates by C. caribbaea were determined at day and night.
Materials and Methods
In December 2015, samples containing the bioeroding sponge Cliona caribbaea were retrieved from dead coral substrate (Diploria spp.), found at a water depth between 3 and 5 m (S = 34 and T = 28°C) at the leeward side of the island of St. Eustatius, Caribbean Netherlands (17.4890° N, 62.9736° W). Annual mean seawater temperature is 27.6°C, varying between 26.1°C in Feb-Mar and 28.2°C in Sept-Oct. Samples were collected using an air drill and hole saw (inner diameter: 40 mm) and transported submerged in ambient SW to an on-shore CO2-controlled experimental set-up. The sponge-infested cores were placed in large flow-through tanks (50 L) for 1 week to allow them to recover from collection and transport. Samples of coral skeleton without bioeroding sponges served as control substrate for the incubations. Collected cores were brushed delicately with a soft brush to remove any non-sponge organisms. The experiment lasted 1 week from December 23 to December 30 2015, excluding acclimatization to the various pCO2 scenarios, which was performed gradually over 6 days from the December 17 to December 22. Each core was photographed at the start (before acclimatization) and at the end of the experiment to assess physical variations throughout the experiment. In addition, fluorescein was released near the ostia half way through the experiment to make sure sponges were still filtering.
Sand-filtered nearshore seawater was continuously supplied to four 200-L barrels in which the pCO2 of the water was maintained at four different levels. Water from each of the four barrels was continuously pumped into nine aquaria of 12 L each, resulting in a total of 36 aquaria distributed across three tables (A, B, and C). Three different levels of dissolved organic and inorganic matter concentrations were maintained in three sets of three aquaria within each pCO2 scenario (Figure 1). All aquaria received an irradiance at levels and spectral quality similar to in-situ conditions, as provided by sunlight passing through Marine Blue filters (#131; Lee filters), and neutral density shading cloth. The aquaria were placed in a 5 cm high flow-through bath of seawater to minimize temperature fluctuations.
Figure 1. Experimental setup consisting of four large barrels in which the pCO2 (4 levels) is manipulated and controlled through a central CO2 sensor. From every barrel, water is pumped into 9 aquaria (12 L each). Of these 9, two groups of 3 aquaria were supplied with additional dissolved organic carbon (E1: green, E2: blue, E3: black) using peristaltic pumps. Pumps ran at different speed between E2 and E3 to deliver different concentration of RPMI. Each of the 36 aquaria contained 2 sponge bearing coral cores (brown squares) and 24 aquaria contained control cores (white squares).
Carbonate chemistry of the water in the four barrels was manipulated using a feedback control system developed in-house, consisting of a central xCO2 sensor (LICOR Inc. model LI-7000), CO2 injectors, CO2 scrubbers and a control computer. In each barrel, water was adjusted to desired pCO2 concentration via air perturbation continuously pumped at high flow (~25 l/min) through a sparger located at the bottom of the barrel to ensure rapid air-sea pCO2 equilibration. Air from the four treatment barrels was sequentially sampled and analyzed for xCO2. Measurements of xCO2 (in ppm) were converted to pCO2 (in μatm) by accounting for average hydrostatic pressure after bubble injection, water temperature and salinity and the humidity of the measurement gas stream following Dickson et al. (2007). Additionally, a zero-standard and ambient air were regularly measured to allow approximate drift-free operation. The measured pCO2 levels were compared by a central computer system to set points and adjusted by either (i) injecting small amount of pure CO2 into the circulated headspace air or (ii) recirculating the air through large soda lime-filled CO2 cartridges to remove CO2. The system allowed treatment and delivery of ~50 liters of water per hour. The four treatments included a pre-industrial scenario (PI; 280 μatm), a present-day scenario (PD; 410 μatm), and two concentrations based on scenarios for potential future atmospheres predicted for 2100 (Solomon, 2007): one based on a ‘reduced’ CO2 emission scenario (RE; 750 μatm) and one based on a ‘business-as-usual’ CO2 emission scenario (BU; 1050 μatm). Reported pCO2 is valid for the culturing temperature (i.e., slightly cooler than the treatment barrels), and estimated to be accurate to within 10 μatm.
Different amounts of dissolved organic and inorganic material were supplied from stock solutions by two 12-channel peristaltic pumps. Roswell Park Memorial Institute (RPMI) 1640 medium was used as the eutrophication supplement. RPMI is a well-known culture medium and it has been used as a growth enhancer on C. crambe sponge explants (Camacho et al., 2006). It contains sugars, inorganic salts, amino acids and vitamins and was used to simulate different levels of eutrophication in the aquaria.
The experiment aimed to provide multiples (1x, 2x, 3x) of the natural near-shore labile DOC concentrations. Labile DOC represents the portion of the total DOC pool on which sponges can feed, here ~20% of ~80 μmolC/kg (Van Duyl and Gast, 2001; De Goeij and Van Duyl, 2007). Treatments were E1: control labile DOC conditions (i.e., only ~16 μmol/kg natural labile DOC), E2: double labile DOC conditions (natural DOC + 16 μmol/kg DOC as RPMI1640) and E3: triple labile DOC conditions (natural + 32 μmol/kg RPMI 1640).
In total, 72 sponge-bearing cores and 24 control cores were collected and distributed evenly over the 12 scenarios, resulting in 2 sponge-bearing cores per aquarium and 2 control cores per scenario. Cores from increased-pCO2 scenarios were exposed to gradually increasing pCO2 over 1 week, ending with the desired pCO2 for that treatment. Addition of RPMI started as scenarios reached their desired pCO2 concentration. Subsequently, sponges were left to acclimatize to their respective carbon dioxide and eutrophication levels for a week prior to the incubations. Cores were placed in closed 0.5 L polycarbonate incubators with inbuilt stirrers in their respective aquaria to keep at constant temperature. Each incubation contained two cores and lasted 6 h to determine chemical bioerosion rates (see Assessment of Bioerosion Rates). The optimum incubation time was determined through trials of 2, 4, 6, and 8 h. Although 6 h was considered the best fit to capture the alkalinity gradient caused by chemical bioerosion, it must be noted that sponges placed in 0.5 L of standing water for more than 1 h would experience lack of food and reduced amounts of oxygen (especially at night) over time. At the end of each incubation, cores were returned to their aquaria.
Temperature and irradiance of the water in the aquaria were recorded every 10 min by 6 HOBO® Pendant UA-002-64 light and temperature loggers and 2 calibrated Odyssey PAR sensors (Dataflow Systems, X, Y), respectively. Salinity was recorded daily in each aquarium using a salinometer (VWR CO310). Oxygen was recorded using a PreSens O2 sensor (Fibox 4, PSt3) after each incubation. Throughout the experiment, every other day around noon, water samples were taken from each treatment to monitor carbonate chemistry, DOC and nutrients. Samples for alkalinity (AT) and dissolved inorganic carbon (DIC) were collected into 250 ml borosilicate bottles and poisoned with 50% saturated HgCl2 solution (final concentration 0.02 %) to arrest biological activity. DOC samples (30 ml) were collected in pre-combusted (550°C) glass vials and acidified with 10 drops of concentrated HCl (37%). Both AT and DIC were measured on a Versatile Instrument for the Determination of Titration Alkalinity (VINDTA) model 3C (Marianda GmbH, Kiel, Germany). Determination of AT was by “open cell” potentiometric acid titration (Mintrop et al., 2000; Dickson et al., 2007) and DIC was measured coulometrically (Johnson et al., 1993; Dickson et al., 2007). Prevention of drift and a high accuracy for AT and DIC were attained by analysis of certified reference material (CRM; supplied by Dr. A. Dickson, Scripps Institution of Oceanography) after every ~20 samples. The full carbonate system state was calculated from the measured temperature, salinity, AT and DIC using the Seacarb package (R-3.2.0) and using the dissociations constants preferred by Dickson and Millero (1987). Samples for determination of nitrate + nitrite, nitrite, phosphate and ammonium were filtered upon collection and stored frozen. Analyses for nutrients were carried out on a QuAAtro continuous flow analyzer (SEAL Analytical, GmbH, Norderstedt, Germany) following GO-SHIP protocol (Hydes et al., 2010). DOC analyses were performed with a total carbon analyzer (TOC-VPN, Shimadzu Corp., Kyoto, Japan).
Assessment of Net Respiration and Photosynthesis Rates
Observed changes in DIC and AT are governed by the combination of respiration and carbonate dissolution and the associated reverse processes of photosynthesis and calcification. The individual contributions of respiration and carbonate dissolution can be disentangled by empirically adjusting observed Δ AT for nutrient effects using the measured nutrient concentration buildup. Indeed, in the case of incubation experiments, all of the change in nutrient concentrations must originate from processes within the incubation chamber. Therefore, this method will result in an appropriate estimate of respiration/dissolution, making calculated bioerosion rates insensitive to errors in measured DIC. Additionally, it takes into account the effect of release of NH4+ on measured AT, which the vector deconvolution does not and cannot, due to the variable release stoichiometry of NH4+. Calculations were carried out as follow:
ΔDICresp was then converted into respiration rates which were used to estimate approximately gross photosynthesis rates as follow:
This method assumes that sponge host respiration is constant during day and night and that symbionts produce 1 mole of O2 for every mole of CO2 they fix.
Assessment of Bioerosion Rates
Total, chemical and mechanical bioerosion rates were quantified. Total bioerosion refers to the sum of both mechanical and chemical bioerosion.
We expressed chemical and mechanical rates both in mg cm−2 h−1 (to distinguish rates between day and night) and in mg cm−2 day−1 (sum of day and night rates). Total bioerosion was expressed in mg cm−2 day−1 using both buoyant weight results and the sum of day and night results for chemical and mechanical bioerosion.
Chemical bioerosion was determined using the alkalinity anomaly technique (Smith and Key, 1975; Chisholm and Gattuso, 1991) involving measured changes in AT (μmol kg−1) associated with dissolution in seawater during 6 h incubation periods and correcting for changes in the concentrations of ammonium, nitrate and phosphate (Jacques and Pilson, 1980; Wisshak et al., 2013). The amount of mass of dissolved calcium carbonate [ΔM(CaCO3), in μg] was calculated using Equation (1) (Zundelevich et al., 2007; Nava and Carballo, 2008):
Where Δ AT is the increase in AT over the incubation period associated with dissolution, VSW is the volume (l) of seawater in the incubation chamber and ρSW is local seawater density (1.022 kg L−1). The multiplication factor “100” represents the molecular mass of CaCO3.
The 6 h incubations were carried out during both the day and at night, starting either 2 h after sunrise and 1 h after sunset, respectively. Subsamples were used for determination of AT and DIC (250 ml, single sample), DOC (30 ml) and nutrient (5 ml) analysis from each chamber at the start and end of each incubation.
Bioerosion rates are commonly expressed as mass of removed substrate per unit surface area of the removing organism per unit time. Rates were therefore converted to mg cm−2 h−1 by expressing the change in AT per surface area of the sponge. Two surface areas of the sponge-bearing cores were determined, the upper circle and the healed surface around the sides of the core.
Mechanical bioerosion was estimated by quantifying the CaCO3 sediment produced by C. caribbaea during 6 h incubations using the method described in Fang et al. (2013b). All remaining incubation chamber seawater (~150 ml) + sediment was collected and the chamber was rinsed with 100 ml water to retrieve any remaining chips. The water was then sieved over a 150 μm mesh to remove non-chip material and then filtered through a precombusted (550°C, 3 h) and pre-weighed GF/F glass microfiber filter (0.7 μm; Whatman). Filters were then combusted at 550°C for 3 h to remove any organic matter and re-weighed to determine the difference in weight and hence that of the sediment produced.
Total bioerosion (both mechanical and chemical) was estimated by the change in buoyant weight of the cores over the week of exposure to different pCO2 and eutrophication scenarios (Fang et al., 2013b). This method assumes organic components of the sponge to have a density equal to that of the ambient seawater (i.e., growth of the sponge will not change buoyant weight of the core). Both sponge cores and control cores were buoyant weighed using electronic scales with 0.1 mg accuracy before and after the week's exposure to the various pCO2 levels. The buoyant mass change of the cores was calibrated for seawater density and corrected by the change in buoyant weight of the control cores, which integrated possible dissolution by other bioeroders, abrasion caused to handling process and accretion due to the potential presence of calcifying organisms.
All statistical analysis were performed using the programming environment R 3.3.2 (R Core Team, 2013). Dependent variables acquired from incubation experiments were analyzed by means of an analysis of covariance (ANCOVA) with two categorical factors (Eutrophication, day/night) including three (E1, E2, and E3) and two (day and night) levels, respectively and one continuous covariate (pCO2). Total bioerosion rates acquired from buoyant weight measurements and net photosynthesis rates were analyzed by means of a 4 × 3 crossed analysis of variance (ANOVA) with two categorical factors (pCO2, eutrophication) including four (BA, PR, RS, and BU) and three (E1, E2, and E3) levels, respectively.
Normality and homoscedacity were confirmed using the Shapiro-Wilk and Levene's test, respectively. If no significant two-way interactions were revealed, main effects were reported. In the case of significant interactive effects, Post hoc tests (Tukey HSD with Bonferroni correction) were applied to determine the effect of a factor at each level of the other.
In addition, linear regression models were performed, after confirming assumptions for residual normality and homoscedacity, between pCO2 (now as a continuous predictor variable) and chemical bioerosion rates for each eutrophication and time levels.
The sponge tissue damaged due to coring healed during the recovery session and started growing along the upper sides of the core throughout the experiment which indicated that sponges were healthy and recovering. Sponge color from the start to the end only varied very slightly, sponges in every treatment became a bit darker which may indicate a higher chlorophyll-a content in symbionts or an increase in symbiont abundance. Fluorescein injections revealed that sponges were still filtering half way through experiment.
Over the course of the experiment, headspace pCO2 in the four barrels remained sufficiently constant to warrant distinction between treatments (Figure 2, Table 1). Calculated mean pCO2 values in the experimental aquaria were 362.5, 443.8, 755.9, and 1046.0 μatm under PI, PD, RE, and BU. The pCO2 levels in PI were on average 82.5 μatm higher than the intended pre-industrial pCO2 levels. However, they remained significantly different from the present scenario and therefore the pre-industrial scenario will be termed “Below-ambient” (BA) in the following text. Sponge cores were exposed to natural variations in temperature and light which, however, proved to be minimal over the experimental period. The average experimental temperature was 27.63°C (min = 25.81°C and max = 29.75°C) and the average light intensity registered inside the aquaria around midday was 562 ± 125.0 μmol photons m−2 s−1. Measured DIC and hence all calculated carbonate system parameters were found to vary significantly across the four OA scenarios (Table 1) and dissolved organic carbon (DOC), ammonium (NH4), and phosphate (PO4) concentrations were found to increase significantly across the eutrophication treatments (Table 2, Supplementary Figure S1).
Figure 2. Temporal variability from December 23 to December 30 2015 of continuously monitored pCO2 (a), temperature monitored in the barrels used for setting the pCO2 experiments (b), temperature measured directly in aquaria from table A, B, and C (c) and light throughout the 1 week experiment.
Table 1. Seawater physical and carbonate chemistry parameters at the start (T0) and the end (T6) of incubation experiments, averaged (±standard deviation) over all incubations for each pCO2 scenario.
Table 2. Initial (T0) and final (T6) DOC and nutrient concentrations averaged over all incubations (± standard deviation) for the three “eutrophication” treatments: “E1” (natural organic loading), “E2” (double labile organic loading), “E3” (triple labile organic loading).
Bioerosion, photosynthesis and respiration within incubations altered the carbonate chemistry of the water (Table 1). Within the holobiont microenvironment, photosynthesis would increase the local pH while respiration would increase local acidification. Throughout all incubations, the pCO2 concentrations increased and the pH and Oaragonite decreased. The change in pCO2, pH and Oaragonite was significantly different between pCO2 scenarios and between day and night. In none of the incubations, Oaragonite reached values below 1. Initial pCO2 concentrations calculated from AT and DIC at the beginning of each chamber incubation were found to increase slightly with addition of RPMI for each OA scenario. Accordingly, pH and CaCO3 saturation state decreased with addition of RPMI for each OA scenario. However, no significant difference was found in calculated pCO2 concentrations, pH, and CaCO3 saturation state between eutrophication treatments in each OA scenario. Dissolved organic carbon and nutrient concentrations increased overall throughout incubations (Table 2, Supplementary Figure S2).
The observed increase in nutrients (Table 2) was not unexpected (Maldonado et al., 2012), but the enhanced concentrations could have interfered S2 with chemical bioerosion measurements. The increase in dissolved organic carbon (Table 2) was likely caused by the confinement of sponges in the incubation chambers, where sponge waste products were re-filtered during the 6 h incubation. Nevertheless, Cliona delitrix, another clinoid sponge, is known to assimilate DOM, which comprises a large part of its diet (Mueller et al., 2014). Despite these confinement effects, relative differences in bioerosional processes between treatments were still observed.
Chemical Bioerosion Rates
In total, 72 chamber incubations were conducted (36 during the day and 36 at night) after 1 week exposure to treatments. Of all incubations, 13 were compromised due to technical complications. The results for the successful 59 incubations are presented here. For the present-day (PD) pCO2 scenario, no data in treatment E2 during the day are available.
As sponges experienced significant increase in pCO2 concentrations throughout incubations, chemical rates were regressed against the average calculated pCO2 obtained from AT and DIC measurement at the start and end of each incubations. As a result, for each pCO2 scenario, day and night pCO2 levels differ from each other.
Chemical bioerosion rates of C. caribbaea increased significantly with pCO2 and eutrophication levels but no interaction was found between the two effects (Figure 3, Tables 3, 5). In addition, day-time chemical bioerosion rates are shown to differ significantly from night-time rates, and an interaction between the effects of pCO2 and day-night is revealed (Tables 3, 4). A post hoc pairwise comparison revealed that the significant differences in chemical bioerosion rates between day and night mostly occurred at low pCO2 scenarios where day time rates were ~50% higher than night-time rates. In high pCO2 scenarios (RE and BU), average day-time and night-time rates were equal in E1 and average night-time rates surpassed day-time ones in E2 and E3 (Table 3). The increase in pCO2 concentration during incubations at day and night was not significantly different between PD, RS, and BU. This indicates that the switch from higher rates during the day at low pCO2 scenarios (BA and PR) to equal/higher rates in RE and BU is not primarily linked to the difference in day and night pCO2.
Figure 3. Chemical bioerosion rates in mg cm−2 h−1 as a function of pCO2 for day and night and each eutrophication treatment. Linear regressions illustrate positive correlation between pCO2 and dissolution rates. Slopes are significantly different between day (blue) and night (black) but not between eutrophication scenarios (E1–E3). Alkalinity titrations for incubations in Present scenario (PD) and E2 treatment during the day were of questionable quality due to equipment failure and therefore not represented here (N = 59).
Table 3. Averages (±standard deviation) of chemical bioerosion rates in mg cm−2 h−1, as calculated from change in AT during incubations.
Table 4. Daily averages (±standard deviation) of total, mechanical, and chemical bioerosion rates in mg cm−2 d−1.
Table 5. Three-way ANCOVAs, with bioerosion rates (chemical: AT change, mechanical: chip production, and total: buoyant weight) and net respiration rates as dependent factors, eutrophication, and day/night as independent categorical factors and pCO2 as a continuous covariable.
Average day and night chemical bioerosion rates increased significantly from E1 to E3 for each of the pCO2 scenarios, however, increases in rates from E1 to E2 were minute and even negative at night (Table 3). Daily chemical rates (mg cm−2 day−1) in BA, PR, RE, and BU increased by 80, 83, 20, and 53% from E1 to E3, respectively (Table 4). Rates in E1 and E3 increased by 150 and 109% respectively from current pCO2 levels to the BU scenario (no PD, E2 chemical rate available).
In these calculations, abiotic dissolution was assumed negligible as aragonite saturation states always remained above 1. Possible bioerosion by other organisms living in the cores is not accounted for in our calculations but is considered minimal throughout the incubation period due to very low AT changes in control core incubations (Supplementary Table S1).
Mechanical and Total Bioerosion Rates
Mechanical bioerosion estimated from chip collection was not significantly different between pCO2 scenarios and eutrophication treatments and no interaction was found between effects (Tables 4, 5). The average hourly mechanical erosion rate for all pCO2 scenarios and eutrophication treatments during day and night equaled 0.02 ± 0.01 mg cm−2 h−1. The average daily rate estimated from the addition of night and day rates equaled to 0.40 ± 0.11 mg cm−2 d−1.
The change in buoyant weight yielded average net bioerosion rates of 2.47 ± 0.16, 2.63 ± 0.25, 2.96 ± 0.33, and 3.34 ± 0.26 mg cm−2 d−1 for BA, PD, RE, and BU, respectively and increased significantly with pCO2 (p = 0.009; Figure 4, Table 5). Although in most pCO2 scenarios, treatment E2 and E3 yielded higher total bioerosion rates than in E1, rates were not found to increase significantly with eutrophication (Figure 4, Table 5). Net bioerosion rates calculated from buoyant weight measurements were ~4–5 times higher than the sum of the measured chemical and mechanical (chips) bioerosion rates at day and night (Figures 4, 5, Table 4).
Figure 4. Total bioerosion rates of C. caribbaea in mg cm−2 d−1 estimated from buoyant weight measurements ± SEM for each pCO2 and eutrophication scenario. Estimates for buoyant weighing are based on all individual measurements (N = 59).
Figure 5. Sum of chemical and mechanical bioerosion in mg cm−2 d−1 for each pCO2 and eutrophication scenario. Mechanical bioerosion rates were estimated using the weight of chips collected during 6 h incubations. Chips were only collected for table A and B during the day and night (N = 44). Chemical bioerosion rates were calculated from ΔAT in incubations (N = 59). Day (24 h) rates were calculated by multiplying day and night mechanical and chemical hourly rates by 12 and adding them together for each pCO2 and eutrophication scenario.
Net Respiration and Photosynthetic Rates
Net holobiont (sponge + symbionts) respiration showed antagonistic behavior between day and night as pCO2 increased. Net respiration during the day decreased with high pCO2 while net respiration at night increased (Figure 6). Rates were found to vary significantly between day and night (p ≤ 0.001) but not between pCO2 scenarios and eutrophication treatments. An interaction between factors day/night and pCO2 levels was revealed (Table 5).
Figure 6. Net respiration rates (Respnet) during the day (dark orange), dark respiration rates (dark Resp) during the night (light orange) and gross photosynthesis (Pgross) of the holobiont (sponge + symbionts) ± SEM for each pCO2 and eutrophication scenario. Pgross was derived from the net respiration of the symbionts (shown as negative respiration in the figure by assuming that 1 mole CO2 respired during the night equals 1 mole O2 produced during the day).
Accordingly, photosynthesis rates (O2 production), estimated from the difference between net respiration rates at day and night, increased significantly with increasing pCO2 (p = 0.004; Figure 6, Table 5). No significant difference was found between primary production and eutrophication scenarios, although photosynthetic activity appeared to decrease with increasing eutrophication in most pCO2 scenarios.
Total bioerosion rates by the common coral excavating sponge Cliona caribbaea are experimentally shown to increase with rising pCO2 (Figure 4), while the corresponding chemical bioerosion component increased significantly with both pCO2 and eutrophication (Figure 3). Mechanical bioerosion exceeded chemical bioerosion by 3–6 times irrespective of pCO2 and eutrophication. Contribution of eutrophication to higher chemical bioerosion rates was additive to pCO2 effects (i.e., not synergetic). Differences between day-time and night-time chemical bioerosion rates at below-ambient and present pCO2 levels suggests that photosynthetic activity by symbionts promotes the dissolution process. While under rising pCO2, the symbiotic relationship appears to become negligible to the bioerosion activity as night-time rates equal/surpass day-time rates.
Effects of pCO2 and Eutrophication on Bioerosion
Results regarding higher rates at increased pCO2 are comparable to previous studies on other clionaid species (C. orientalis and C. celata) (Wisshak et al., 2012, 2013, 2014; Fang et al., 2013a). Sponges and other borers are assumed to benefit from eutrophication (Holmes, 2000; Carballo et al., 2008). Many sponges on reefs harbor photosynthetic symbionts and in some cases they produce >50% of the energy requirements of the host (Erwin and Thacker, 2008). They rely nevertheless also on organic matter for food and their feeding strategy may be flexible depending on the type of symbionts or the environmental conditions. To maintain a positive energy budget, C. caribbaea likely relies mainly on autotrophic products (Weisz et al., 2010; Fang et al., 2014) and thus depends on the supply of organic matter for maintenance and growth from its photosymbionts. Considering the low phosphate concentrations in E1 (~0.01 μmol l−1), primary production may have been limited by phosphate. However, the addition of RPMI and hence higher phosphate concentrations did not enhance photosynthetic activity from E1 to E3. On the contrary, in most pCO2 scenarios, net primary production estimates decreased slightly (non-significant) from E1 to E3, while sponge chemical bioerosion rates were enhanced. It should be noted here that potential light limitation of symbiont photosynthesis in the incubations tanks may not be discounted. Under increased organic matter and nutrient levels, the sponges may be less dependent on autotrophic products. However, as the increase in chemical bioerosion rates from E1 to E3 was more pronounced during the day (at low and ambient pCO2 levels), it is likely that the autotrophic/heterotrophic ratio of energy supply only shifts slightly toward heterotrophy and the sponges still rely partly on autotrophic products.
Chemical bioerosion rates at night-time increase also (at a lesser degree) with higher eutrophication, indicating that chemical bioerosion does indeed benefit from a higher energy supply via heterotrophic feeding. This implies that increased eutrophication did not impact the productivity of the symbionts. Sponges, like corals, can exercise control on symbiont growth and abundance by inhibiting division or ingesting them to maintain population size near a carrying capacity (Hill, 2014).
Total bioerosion rates calculated using buoyant weight measurements were experimentally shown to increase significantly with pCO2 but not with eutrophication. These results are unexpected considering the significant impact eutrophication has on chemical bioerosion. However, the relatively short term experiment coupled with the smaller effect of eutrophication on chemical rates compared to the pCO2 impact may have obscured this signal.
Total bioerosion rates estimated from buoyant weights resulted in ~5 times higher rates than those based on the sum of chip production and the change in AT (Figures 4, 5). This is comparable to results from Fang et al. (2013a) and may be explained by an underestimation of the chip removal capacity of the sponge. Rates calculated using buoyant weight measurements are based on a longer period of bioerosion (1 week), whereas the chip removal is based on their collection at the end of a relatively short incubation period (6 h). Sponges might expel chips irregularly or they may temporarily reduce chip removal during incubations possibly due to stress caused by reduced food supply or build-up of waste products, both of which may become important toward the end of the 6 h-incubation period. Therefore, the sum of chemical and mechanical bioerosion should be considered as being conservative. Here, total bioerosion rates yielded from buoyant weight measurements are regarded as more reliable and are comparable to results estimated from previous studies (Fang et al., 2013a; Wisshak et al., 2013).
Rates of chip production did not differ significantly between pCO2 scenarios, day/night and eutrophication treatments. Although the underlying method by which sponges expel chips is largely unknown, it appears that chips are expelled from the sponge body through excurrent canals (Rützler and Rieger, 1973). It is likely that chip removal processes utilize products from the dissolution to contract their tissue and move the chip up from the boring pit into an excurrent canal. Work on phototrophic cyanobacteria showed that microbial excavation was achieved by transcellular Ca2+ transport (Garcia-Pichel, 2006; Garcia-Pichel et al., 2010; Guida and Garcia-Pichel, 2016). We tentatively suggest that the excess in Ca2+ derived from the dissolution in may be used by sponges to contract a conductive pathway, similarly to how muscle cell contract when triggered by an increase in intracellular Ca2+ (Sommerville and Hartshorne, 1986).
Respiration, Photosynthesis and Changes in Chemical Bioerosion Rates
Changes in chemical bioerosion activity can be associated with three processes within the holobiont: CO2 fixation/respiration by the symbionts, respiration by the sponge and chemical bioerosion. Photosynthesis promotes chemical bioerosion rates during the day at low pCO2 levels (BA and PD) (Figure 3, Table 3). Differences in rates between day and night are comparable to results from previous studies where C. orientalis and C. varians (both symbiont bearing species) excavated with higher rates in day light compared to the dark or shade at ambient pCO2 (Hill, 1996; Schönberg, 2006; Fang et al., 2016). Recent work by Fang et al. (2016) on the ecophysiology of C. orientalis showed that bioerosion rates in this sponge during day-time were ~40% higher than in the dark. C. celata on the other hand, an azooxanthellate sponge, displayed no diurnal variability in bioerosion pattern (Schönberg, 2008). Based on these findings, presence of Symbiodinium spp. was assumed to be associated with higher bioerosion rates (Hill, 1996; Fang et al., 2016). Geochemically speaking, this is a paradox because the autotrophic symbionts would tend to increase pH, increase saturation state and thereby aid carbonate precipitation rather than its antagonistic process (Garcia-Pichel et al., 2010).
However, local acidification due to sponge respiration may balance out the increase in pH associated with photosynthesis. As symbionts do not produce a favorable environment for carbonate dissolution, photosynthesis must therefore supply a high fraction of the energetic costs of the bioerosion process which may include ATP usage for active Ca2+ and/or active proton pumping (Guida and Garcia-Pichel, 2016). Higher rates during the day at low and ambient pCO2 indicate that the benefit of acquired energy from photosynthetic activity exceeds the benefit of increased pCO2 levels at night due to respiration.
Due to the sponge's energetic dependence on photosynthates for enhanced bioerosion activity, the capacity of phototrophic sponges to excavate may be particularly sensitive to environmental changes impacting photosynthesis. Our results suggest that photosynthesis is enhanced with increased pCO2 (Figure 6), possibly due to a switch from to CO2 uptake. Fang et al. (2014) describes a greater supply of photosynthetic products from symbionts in the “reduced emissions” scenario (pCO2 = 645 μatm, temperature = 28.4°C) to meet higher metabolic demands. Photosynthetic products by symbionts may be used for biosynthesis and respiration by the zooxanthellae or transferred to the associated sponge where it is used for metabolic maintenance via respiration or growth (Fang et al., 2014).
Despite enhanced photosynthetic rates with rising pCO2, day-time chemical rates did not seem to benefit from this boost in energy supply as they were found to be comparable and even lower than night-time rates. The relationship between the sponge and its symbionts regarding bioerosional processes seems to change at higher pCO2. We hypothesize that the increase in local pH associated with enhanced photosynthesis may be too large to be balanced out by local respiration acidification. In other words, the increased photosynthetic activity may have an antagonistic effect with respect to acidification during day-time due to higher uptake of CO2 by the symbionts. Borges and Gypens (2010) argued that the effect of enhanced primary production on carbon cycling can counter the effect of ocean acidification. Increased respiration might stimulate primary production by increased translocation of CO2 of the sponge to the symbionts. The antagonistic behavior of trends observed between respiration at night and net respiration during the day with rising pCO2, is attributed to enhanced photosynthesis resulting in greater CO2 fixation by photosymbionts.
Furthermore, competition for dissolved inorganic carbon species may occur between bioerosion and photosynthetic activity by the symbionts.
Comparison and Extrapolation of Bioerosion Rates
Estimates of chemical and mechanical bioerosion for C. caribbaea are comparable to those calculated for C. orientalis under a range of CO2 concentrations (Fang et al., 2013a; Wisshak et al., 2013, 2014). This is consistent with the membership of C. caribbaea to the Cliona viridis-complex (Schönberg, 2002). Our chemical rates ranged from 0.06 to 0.15 mg cm−2 day−1 from present day to business-as-usual pCO2 levels. Estimates by Fang et al. (2013a) ranged from 0.08 to 0.3 mg cm−2 day−1 while rates by Wisshak et al. (2014) ranged from 0.02 to 0.26 mg cm−2 day−1. Mechanical rates from Fang ranged from 0.12 to 0.16 mg cm−2 day−1 whilst our results ranged from 0.23 to 0.5 mg cm−2 day−1 (in E1). Total bioerosion rates from this study were nearly three times higher than those of Fang et al. (2013a) and Wisshak et al. (2014). Discrepancies between results can be attributed to differences in the methodology and calculations between these experiments. For instance, Wisshak et al. (2014) only conducted dark incubations which would explain the relatively low rates at ambient pCO2. These inconsistencies in the methodology between experiments are complicating comparison between results from different studies. Therefore, there is a need for method standardization regarding sponge bioerosion rates experiments. In addition, incubation methods are affecting sponges and are preventing accurate determination of rates. Up to now, closed incubations have been sufficient to observe relative variation between pCO2, temperature and eutrophication treatments. This sheds light on how boring sponges may react to future environmental changes. However, if we are to quantify such reaction, it is essential that rates are more accurately measured. Using semi enclosed incubation chambers may increase accuracy of chemical rates greatly. As the method involved in quantifying mechanical bioerosion rates is regarded as untrustworthy, collection of chips should be applied to a longer stretch in time.
Extrapolations should be treated with caution as it is an enormous jump to go from 6 h incubations to yearly estimates (McElhany, 2016), especially considering how seasonality and therefore different irradiance levels of light may impact bieoerosion rates of photosymbiotic sponges. Still, when extrapolating chemical bioerosion rates from our experiment to yearly estimates, rates in the present-day (PD) pCO2 scenario and in the business as usual (BU) scenario ranged from 0.22 to 0.55 kg m−2 year−1 in E1 and from 0.40 to 0.84 kg m−2 year−1 in E3. This corresponds to a doubling of rates by the end of this century. Even in a slightly more optimistic scenario, where CO2 emissions are reduced, chemical bioerosion rates would increase by 50% compared to present rates. However, combined effects of pCO2 and eutrophication, result in rates ranging from 0.22 kg m−2 year−1 in PD: E1 to 0.84 kg m−2 year−1 in BU: E3 which nearly corresponds to a quadrupling in chemical bioerosion rates.
Considering ongoing ocean acidification, combined with increasing coastal eutrophication around Caribbean islands, these finding suggests that sponge bioerosion will increase in the next century. The combined effect of OA and eutrophication on bioerosional activity was not synergetic but additive. Enhanced bioerosion in future oceans together with reduced calcifying potential of corals will inevitably tip the balance between reef accretion and bioerosion processes toward net loss of carbonate structure.
Results from our incubation experiments increases our understanding of the effect of symbionts on bioerosional activity. Greater chemical bioerosion during the day at low and ambient pCO2 suggest that the energy gained by photosynthetic activity is fueling a high fraction of the metabolic cost at the site of erosion which may include ATP usage for active Ca2+ and/or active proton pumping. At higher pCO2, enhanced photosynthesis appears to have an antagonistic effect with respect to acidification due to higher uptake of CO2 by the symbionts. Finally, our results stress the need to explore in more detail the role of light on the regulation of photosymbiotic sponge bioerosion rates.
Data collection: AW and DdB; Data analysis: AW; Interpretation of the data: AW, SvH, DdB, FvD, GR, and LdN; Drafting work: AW; Critical revision: FvD, SvH, GR, and LdN; Final approval: AW, SvH, DdB, FvD, GR, and LdN; Agreement to be accountable for all aspects of the work AW, SvH, DdB, FvD, GR, and LdN.
Conflict of Interest Statement
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
We would like to thank two reviewers for their constructive comments which improve the initial manuscript. We thank the Caribbean Netherlands Science Institute (CNSI) for hosting the experiment and especially Johan Staple for his support. We also thank Masru Spanner for the nutrient analyses and Santiago Gonzalez for the dissolved organic carbon analyses and Paul Peters for field assistance. Bob Koster is gratefully acknowledged for the design and development of the pCO2 set-up just as the NIOZ workshop whose help and work was crucial for the construction of the experimental set-up. This work is supported by the Gravitation grant NESSC from the Dutch Ministry of Education, Culture and Science. External funding for this project was provided by the Netherlands Organization for Scientific Research (NWO grants 858.14.021 and 858.14.022).
The Supplementary Material for this article can be found online at: https://www.frontiersin.org/article/10.3389/fmars.2017.00311/full#supplementary-material
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Keywords: sponge bioerosion, ocean acidification, eutrophication, coral reef, diurnal rhythm, sponge symbionts
Citation: Webb AE, van Heuven SMAC, de Bakker DM, van Duyl FC, Reichart G-J and de Nooijer LJ (2017) Combined Effects of Experimental Acidification and Eutrophication on Reef Sponge Bioerosion Rates. Front. Mar. Sci. 4:311. doi: 10.3389/fmars.2017.00311
Received: 06 June 2017; Accepted: 12 September 2017;
Published: 26 September 2017.
Edited by:Hajime Kayanne, The University of Tokyo, Japan
Reviewed by:Max Wisshak, Senckenberg Nature Research Society, Germany
Susana Enríquez, National Autonomous University of Mexico, Mexico
Copyright © 2017 Webb, van Heuven, de Bakker, van Duyl, Reichart and de Nooijer. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Alice E. Webb, firstname.lastname@example.org | <urn:uuid:b4575bdb-2039-484a-a547-9e7904f54e7b> | 2.578125 | 15,668 | Academic Writing | Science & Tech. | 53.553623 | 95,515,646 |
Jun 8, 2018
Stat: The penguin population in Punta Tombo,
Argentina, has declined by 43 percent since 1987.
Story: Not all of those birds are dying: Many are relocating to areas with more prey—a move aided by their ability to swim 170 kilometers a day—and 200,000 breeding pairs remain in Punta Tombo. But expert Dee Boersma, known as the Jane Goodall of penguins, says the decline may foretell worrying trends in the ecosystem. Host Dan LeDuc sits down with Boersma, and hears from a few of the penguins, to learn more. | <urn:uuid:fad4eea9-cc2e-4e83-a31c-74dfd0b0ce4c> | 2.515625 | 138 | Truncated | Science & Tech. | 57.8825 | 95,515,649 |
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Enjoy some of the extensive magazine, newspaper and web-based coverage of our work through the years.
Enjoy a sampling of print media featuring Dr. Nichols' efforts collected on ISSU.
Graceful and deliberate, sea turtles tend our ocean lagoons and coral reefs, returning to land to lay their eggs. In the South China Sea, Indonesia's 250-island Anambas chain, some distance from this week's tragic earthquake, includes the half-mile-long Durai Island. This island is where most of the region's sea turtles nest -- a practice that could have come to an end.
But thanks in part to the involvement of California scientist and activist Dr. Wallace J. Nichols, successful nesting in the Anambas will continue -- as will the turtles' key role in the area's reef and marine systems.
There are at least two species that nest on Anambas' beaches, the hawksbill turtle and the green turtle. Green turtles eat mostly seagrass, migrate long distances, feeding in one location and nesting in another. Hawksbill turtles migrate less and eat primarily sponges on nearby reefs.
Thousands of turtles arrive to the island, largely between July and September. Green and hawksbill turtles nest together, at night, laying a hundred or more eggs in large holes on the beach. Hatchlings emerge two months later -- at night or in the early morning light.
Sea turtles begin to lay eggs when they are 20 years old or more and continue every three years throughout their lives -- usually until 80 years. If a turtle survives incubation and hatches, it still has to travel from the nest to the shoreline and across the reef where fish, birds and other prey wait. Once past the
reef, the young turtle has a chance of survival in the open sea.
In the Anambas, most turtles never hatched. Virtually all the eggs were gathered and sold at the local market within 24 hours. The eggs were then boiled and their contents sucked out of their soft leathery shells. Years of egg harvesting took their toll.
Pak Lahanie is Durai Island's 92-year-old caretaker who has collected turtle eggs for 40 years. The beaches he works are owned in parcels by five men, each received proceeds from the eggs on his section. The population declined during peak season from more than 80 turtles per night to fewer than 20. The island is surrounded by coral reef and has no fresh water.
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In the meantime, Pak Lahanie is happy to use his vast experience to protect sea turtles -- some 250,000 hatchlings will be saved each year.
If you're not in a hurry, watch the 12½ minute un-narrated video that was shown to the Durai Island's owners before their discussion with Nichols began: http://vimeo.com/3649571.
Dan Haifley is the executive director of O'Neill Sea Odyssey. He can be reached email@example.com.
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A leaflet (occasionally called foliole) in botany is a leaf-like part of a compound leaf. Though it resembles an entire leaf, a leaflet is not borne on a main plant stem or branch, as a leaf is, but rather on a petiole or a branch of the leaf. Compound leaves are common in many plant families and they differ widely in morphology. The two main classes of compound leaf morphology are palmate and pinnate. For example, a hemp plant has palmate compound leaves, whereas some species of Acacia have pinnate leaves.
The ultimate free division (or leaflet) of a compound leaf, or a pinnate subdivision of a multipinnate leaf is called a pinnule or pinnula.
|Look up leaflet (botany) in Wiktionary, the free dictionary.|
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The Earth-Atmosphere Momentum Budget: Remaining Discrepancies at High and Low Frequencies
In recent years, it has been well established that the (axial) angular momentum of the atmosphere and that of the solid earth are closely related on a variety of time scales. On the subseasonal scale, for example, 30–50 day atmospheric fluctuations are strongly mirrored in the rotation of the earth (Langley et al., 1981). On seasonal scales, annual and semiannual cycles in the momentum of the atmosphere are matched by those of the earth (Rosen and Salstein, 1985). At inter- annual time scales, features such as the El Nino-Southern Oscillation (ENSO) and the stratospheric quasi-biennial oscillation have been shown to be related to the earth’s rotation rate (Rosen et al., 1984; Chao, 1989). However, on the very shortest and longest time scales the atmospheric and geodetic momentum series appear to diverge, even when measured by the most recent techniques. The purpose of this note is to outline the character of the disagreement at these two time scales. A fuller discussion, including details of our analysis methods, appears in Rosen et al. (1990).
KeywordsSolid Earth Earth Rotation Atmospheric Angular Momentum Momentum Budget Energy Density Spectrum
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- Dickey, J.O., T.M. Eubanks, and R. Hide (1989). Interannual and decade fluctuations in the earth’s rotation, Proceedings of IUGG Symposium on Variations in the Earth’s Rotation, IUGG XIX General Assembly (Vancouver, August 1987), Geophysical Monograph Series, AGU, in press.Google Scholar
- Hide, R. (1986). Presidential address: The earth’s differential rotation, Quart. J. Roy. Astron. Soc. 27, 3–20.Google Scholar
- Morabito, D.D., T.M. Eubanks, and J.A. Steppe (1988). Kalman filtering of earth orientation changes, The Earth’s Rotation and Reference Frames for Geodesy and Geodynamics, A.K. Babcock and G.A. Wilkins (eds.), Kluwer Academic Publishers, pp. 257–267.Google Scholar
- Rosen, R.D., D.A. Salstein, and T.M. Wood (1990). Discrepancies in the earth-atmosphere angular momentum budget. J. Geophys. Res., in press.Google Scholar
- Salstein, D.A., and R.D. Rosen (1985). Computations of atmospheric angular momentum, with emphasis on the MERIT period. Proceedings of the International Conference on Earth Rotation and the Terrestrial Reference Frame, Columbus, Ohio, Department of Geodetic Science and Surveying, The Ohio State University, Columbus, OH 43210.Google Scholar | <urn:uuid:1d68614b-4418-40bd-9a29-fcf18d961dfd> | 2.546875 | 617 | Academic Writing | Science & Tech. | 56.335673 | 95,515,698 |
One-Phase Newtonian Flow
This section is devoted to the derivation of Darcy’s law for an incompressible viscous fluid flowing in a porous medium. Starting from the steady Stokes equations in a periodic porous medium, with a no-slip (Dirichlet) boundary condition on the solid pores, Darcy’s law is rigorously obtained by periodic homogenization using the two-scale convergence method. The assumption of the periodicity of the porous medium is by no means realistic, but it allows casting this problem in a very simple framework and proving theorems without too much effort. We denote by e the ratio of the period to the overall size of the porous medium. It is the small parameter of our asymptotic analysis because the pore size is usually much smaller than the characteristic length of the reservoir. The porous medium is contained in a domain Q, and its fluid part is denoted by TE. From a mathematical point of view, 513E is a periodically perforated domain, i.e., it has many small holes of size ε which represent solid obstacles that the fluid cannot penetrate.
KeywordsPorous Medium Homogenize Problem Stokes System Cell Problem Perforated Domain
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Presentation on theme: "Molecular Geometry and Bonding Theories Brown, LeMay Ch 9 AP Chemistry Monta Vista High School Ch 9 PS #8, 10, 16, 20 (and draw overall dipole moments),"— Presentation transcript:
Molecular Geometry and Bonding Theories Brown, LeMay Ch 9 AP Chemistry Monta Vista High School Ch 9 PS #8, 10, 16, 20 (and draw overall dipole moments), 30, 34, 36, 41, 59, 73; Recommended #9, 11, 13, 19, 25, 31, 40, 55, 60
Lewis structure is a flat drawing showing the relative placement of atoms, bonds etc. in a molecule, but does not tell anything about the shape of the molecule. VSEPR theory helps construct molecular shape (3-D) from the Lewis structures, which are 2-D structures. Rationale for VSEPR Theory
Valence Shell Electron Pair Repulsion Theroy The basis principal of VSEPR is that each group of valence electrons (electron domains) around a central atom tend to be as far as possible from each other to minimize repulsions. These electron domain repulsions around the central atom determine the molecular geometry of a molecule. Electron domains: areas of valence e - density around the central atom; Includes bonding e - pairs and nonbonding (lone) e - pairs A single, double, or triple bond counts as one domain Repulsions between two e domains are : lone pair- lonepair >lone pair-bond pair> bond pair-bond pair
Valence-shell electron-pair repulsion theory – Why is lone pair- lone pair repulsion greater than bond pair-bond pair repulsion? – Good Links: Good Power point on VSEPR, Shapes of sp3, sp2, sp Carbon, VSEPR Lecture Good Power point on VSEPRShapes of sp3, sp2, sp CarbonVSEPR Lecture Summary of ABE (Tables 9.1 - 9.3) on the next slide: E = lone or non-bonding pairs A = central atom B = bonded atoms Bond angles notation used here: < xº means ~2-3º less than predicted << xº means ~4-6º less than predicted
Tables Link Link # of e - domains & # and type of hybrid orbitals e - domain geometry Formula & Molecular geometry Predicted bond angle(s) Example (Lewis structure with molecular shape) 2 Two sp hybrid orbitals Linear AB 2 Linear 180º BeF 2 CO 2 A |X|X X A |B|B B
3 Three sp 2 hybrid orbitals Trigonal planar AB 3 Trigonal planar 120º BF 3 Cl-C-Cl << 120º Cl 2 CO LAB 2 Bent < 120º NO 2 1- A |X|X XX A |B|B BB A |B|B :B
Example: CH 4 Molecular shape = tetrahedral Bond angle = 109.5º H | H—C—H | H 109.5º
4 Four sp 3 hybrid orbitals or Tetrahedral AB 4 Tetrahedral 109.5º CH 4 LAB 3 Trigonal pyramidal < 109.5º Ex: NH 3 = 107º NH 3 L 2 AB 2 Bent <<109.5º Ex: H 2 O = 104.5º H2OH2O X A X X X X A X XX B A B BB : A B BB : A B B:
5 Five sp 3 d hybrid orbitals Trigonal bipyramidal AB 5 Trigonal bipyramidal Equatorial = 120º Axial = 90º PCl 5 LAB 4 Seesaw Equatorial < 120º Axial < 90º SF 4 X X X A X |X|X B B B A B |B|B : B - A - B B B
5 Five sp 3 d hybrid orbitals Trigonal bipyramidal L 2 AB 3 T-shaped Axial << 90º ClF 3 L 3 AB 2 Linear Axial = 180º XeF 2 X X X A X |X|X B : : A B |B|B : : : A B |B|B
6 Six sp 3 d 2 hybrid orbitals or Octahedral AB 6 Octahedral 90º SF 6 LAB 5 Square pyramidal < 90º BrF 5 X X A X |X|X X X B B A B |B|B B B B B A B |.. B B A X |X|X XX X X
6 Six sp 3 d 2 hybrid orbitals or L 2 AB 4 Square planar 90º XeF 4 or L 3 AB 3 T-shaped <90º KrCl 3 1- A B |B|B BB.. B B A |.. B B B B A.. |.... B A |B|B BB
Limitations of VSEPR Theory Even though the VSEPR model is useful in predicting the shapes of molecules, it does not differentiate between single, double and triple bonds and does not account for bond strengths.
9.3: Molecular Polarity Two factors must be considered in the polarity of a molecule: 1.Are the individual bonds (joining different atoms in a molecule) polar? Ex. HCl vs. H 2. HCl is polar while H 2 is not. H-Cl: : : : : + - Bond polarity is most often represented by an arrow that points toward the - (most EN atom), showing the shift in e - density. The dipole moment ( ) is a vector (i.e., has a specific direction) measuring the polarity of a bond which contains partial charges (Q) that are separated by a distance (r). = Q r
2. If individual bonds are polar, then do individual dipole moments cancel out or not. A molecule is polar if its centers of (+) and (-) charge do not cancel out- generally happens in a distorted molecule (molecules with lone pairs of e on the central atom.) How to determine if a molecule is polar? The sum of the bond dipole moments in a molecule determines the overall polarity of the molecule. 1.Draw the true molecular geometry (3D geometry). 2.Draw each bond dipole as an arrow 3.Add the vectors, and draw the overall dipole moment. If none, then = 0. 4.Generally, a distorted molecule (with lone pairs on the central atom) will have a dipole. Exception: AB2E3 type
What is the big deal about polarity? The polarity of a molecule will tell you a lot about its solubility, boiling point, etc. when you compare it to other similar molecules. Water, for example, is a very light molecule (lighter than oxygen gas or nitrogen gas) and you might expect it would be a gas based on its molecular weight, however the polarity of water makes the molecules "stick together" very well. Hence water is present as liquid. Polar substances are soluble in water (which is polar) and non polar substances are soluble in non polar solvents such as benzene and oil.
Ex: Draw molecular geometires, bond dipole moments, and overall dipole moments. Also, name the e - domain geometry and the molecular geometry. CO 2 BF 3 H 2 O CCl 4 NH 3 PH 3
Rationale For Valence Bond Theory VB theory provides a basis for covalent bond formation based upon overlapping of atomic orbitals to share electrons. This theory successfully predicts bond strengths based upon orbital overlap (such as H 2 bond being weaker than N 2 bond)- sigma vs. pi bond strength
Covalent Bonding and Orbital Overlap: Valence Bond Theory The basic principle of VB theory is that a covalent bond forms when the orbitals of two atoms overlap. Three central themes of VB theory derive from this principle: 1. Opposing spins of e pairs: In accordance with Pauli’s exclusion principle, an orbital can have max of two e with opposite spins. 2. Maximum overlap of bonding orbitals: The bond strength depends upon the attraction of nuclei for the shared e, so the greater the overlap, the stronger the bond. 3. End to end overlap of the atomic orbitals form a sigma bond and allows the free rotation of the parts of the molecule. Side-to-side overlap forms a pi bond, which restricts rotation. A multiple bond consists of one sigma bond and rest pi bonds.
Sigma and Pi bonds Sigma ( ) bond: Covalent bond that results from axial overlap of orbitals between atoms in a molecule Lie directly on internuclear axis “Single” bonds, could form between s-s orbital or s-p orbital or p-p orbital by axial overlapping Ex: F 2 Pi ( ) bond: Covalent bond that results from side-by-side overlap of orbitals between atoms in a molecule. Are “above & below” and “left & right” of the inter nuclear axis and therefore have less total orbital overlap, so they are weaker than bonds. Forms between two p orbitals (py or pz) Make up the 2 nd and 3 rd bonds in double & triple bonds. Ex: O 2 N 2
Covalent Bonding and Orbital Overlap Valence-bond theory: overlap of orbitals between atoms results in a shared valence e - pair (i.e., bonding pair) Energy (kJ/mol) 0 -436 0.74 Å H-H distance Figure : Formation of bond in H 2 a.As 2 H atoms approach, the 2 valence e- in the 1s orbitals begin to overlap, becoming more stable. b.As H-H distance approaches 0.74 Å, energy lowers b/c of electrostatic attraction between the nuclei & the incoming e-. c.When H-H distance = 0.74 Å, energy is at its lowest because electrostatic attractions & repulsions are balanced. (This is the actual H-H bond distance. d.When H-H distance < 0.74 Å, energy increases b/c of electrostatic repulsion between 2 nuclei & between the 2 e-. a b c d
Limitations of VB Theory Valence bond (VB) theory assumes that all bonds formed between two atoms are localized bonds and are formed by the donation of an electron from each atom. This is actually an invalid assumption because many atoms bond using delocalized electrons.
Rationale for Hybrid Orbital Theory Good youtube video Good youtube video Hybrid orbital theory is seen as an extension of VB theory, where atomic orbitals “hybridize” to form new hybrid orbitals. This hybrid orbital theory helps explains the bonding in terms of quantum mechanical model of atom (s,p,d,f orbitals).
9.5: Hybrid Orbital Theory Movie on Hybrid Orbitals Movie on Hybrid Orbitals Explains the molecular geometries in terms of s,p,d,f orbitals. VSEPR explains that e domains must be farthest from each other around central atom, but fails to explain these in terms of orbitals as defined in wave mechanical model of atom. Hybrid orbital theory of Linus Pauling proposed that the valence atomic orbitals in the molecule are very different from those in the isolated atoms. The process of orbital mixing is called hybridization, and the new atomic orbitals are called hybrid orbitals. Animation on Hybrid Orbitals, Hybridization Movie Animation on Hybrid Orbitals Hybridization Movie
Hybrid Orbital Theory Two key points about the number and types of hybrid orbitals are that 1. The number of hybrid orbitals obtained equals the number of atomic orbitals mixed. 2. The type of hybrid orbitals obtained varies with the types of atomic orbitals mixed.
“sp” hybrid orbitals BeF 2 (g): observed as a linear molecule with 2 equal-length Be-F bonds. Valence bond theory predicts that each bond is an overlap of one Be 2s e - and one 2p e - of F. However, Be’s 2s e - are already paired. So… To form 2 equal bonds with 2 F atoms: 1.In Be, one 2s e - is promoted to an empty 2p orbital. 2.The occupied s and p orbitals are hybridized (“mixed”), producing two equivalent “sp” orbitals. 3.As the two “sp” hybrid orbitals of Be overlap with two p orbitals of F, stronger bonds result than would be expected from a normal Be s and F p overlap. (This makes up for energy needed to promote the Be e - originally.)
Be (ground state) → Be (promoted) → Be (sp hybrid) 2p 2s Energy → Orbital “shapes” One s + one p → Two sp orbitals (to bond with 2 F’s) A central atom in a Lewis structure with exactly 2 e - domains has sp hybrid orbitals. F
“sp 2 ” hybrid orbitals BF 3 (g): observed as trigonal planar molecule with 3 equal-length B-F bonds. However, 2 valence e- in B are paired, and are the s and p e - not at the observed 120 º angle. 2p 2s One s + two p → Three sp 2 orbitals (to bond with 3 F’s) A central atom with exactly 3 e- domains has sp 2 hybrid orbitals. B (ground) → B (promoted) → B (sp 2 hybrid) F F F
“sp 3 ” hybrid orbitals CH 4 (g): observed as tetrahedral 2p 2s One s + three p → Four sp 3 orbitals (to bond with 4 H’s) A central atom with exactly 4 e- domains has sp 3 hybrid orbitals. C (ground) → C (promoted) → C (sp 3 hybrid) H H
“sp 3 d” hybrid orbitals (or dsp 3 ) PCl 5 (g): observed as trigonal bipyramidal; forms 5 bonds of equal energy (* but not equal length: equatorial are slightly longer) 3d 3p 3s One s + three p + one d → Five sp 3 d orbitals (to bond with 5 Cl’s) A central atom with exactly 5 e- domains has sp 3 d hybrid orbitals. P (ground) → P (promoted) → P (sp 3 d hybrid) Cl Cl Cl Cl Cl
“sp 3 d 2 ” hybrid orbitals (or d 2 sp 3 ) SF 6 (g): observed as octahedral; forms 6 equal-length bonds One s + three p + two d → Six sp 3 d 2 orbitals A central atom with exactly 6 e- domains has sp 3 d 2 hybrids.
Non-bonding e- pairs Lone pairs occupy hybrid orbitals, too Ex: H 2 O (g): observed as bent; but e- domain is tetrahedral 2p 2s Four sp 3 orbitals (2 bonding, 2 non-bonding) O (ground) → O (sp 3 hybrid) 2 non-bonding pairs (lone pairs) 2 bonding pairs H
9.6: Multiple Bonds Draw Lewis structures. For C’s: label hybridization, molecular geometry, and unique bond angles C 2 H 6 C 2 H 4 C 2 H 2 C 6 H 6
Sigma ( ) bonds in C 2 H 4 Ex: ethene; C-C -bonds and C-H -bonds result from axial overlap of H s-orbitals and C sp 2 - orbitals
Pi ( ) bonds in C 2 H 4 Each C has 4 valence e - : – 3 e - for 3 bonds – 1 e - for 1 bond, which results from side-by-side overlap of one non-hybridized p-orbital from each C 2p C 2s sp 2 hybrids bond axially = bonds p orbital bonds side-by-side = bond
Sigma ( ) bonds in C 2 H 2 Ex: ethyne (a.k.a. acetylene) C-C -bond and C-H - bonds result from axial overlap of H s-orbitals and C sp-orbital
Pi ( ) bonds in C 2 H 2 Each C has 4 valence e - : – 2 e - for 2 bonds – 2 e - for 2 bonds, which result from side-by-side overlap of two non-hybridized p-orbitals from each carbon sp hybrids bond axially = bonds 2p C 2s p orbital bonds side-by-side = bonds
Sigma ( ) bonds in C 6 H 6 Ex: benzene; C-C -bonds and C-H -bonds result from axial overlap of H s-orbitals and C sp 2 - orbitals http://www2.chemistry.msu.edu/faculty/reusch/VirtTxtJml/intro3.htm#strc8c
Localized v. Delocalized Bonds Delocalized bonds are present in compounds showing resonance structures, while electrons are localized in most other bonds.
Localized vs. Delocalized Bonds (localized)(delocalized – MINIMUM OF 4 c’S)
Delocalized bonds in C 6 H 6 C-C -bonds result from overlap of one non-hybridized p-orbitals from each C Delocalization of e - in -bonds results in a “double-donut” shaped e - cloud above and below the molecular carbon plane.
Limitations of Hybrid Orbital Theory Hybrid orbital theory assumes that all bonds are formed with localized electrons, which is not true. MO (Molecular Orbital) theory explains bonding in terms of delocalized orbitals as well.
9.7: Molecular Orbital (MO) theory So far we have used valence-bond theory (covalent bonds form from overlapping orbitals between atoms) with hybrid orbital theory and VSEPR theory to connect Lewis structures to observed molecular geometries. However, VB theory does not explain the magnetic or spectral properties of a molecule. MO theory is similar to atomic orbital (AO) theory (s, p, d, f orbitals) and helps to further explain some observed phenomena, like unpredicted magnetic properties in molecules like those in O 2. AO are associated with the individual atoms, but MO are associated with the whole molecule.
*AO & MO in H 2 Combination of two 1s AO from each H forms two MO in H 2 molecule. Bonding MO: form between nuclei and are stable Antibonding MO: marked with *; form “behind” nuclei and are less stable. 1s Molecular orbitals E 1s * 1s Atomic orbitals Bonding orbital Anti-bonding orbital
*Types of MO Sigma ( ) MO: form from combinations of: – Two 1s or 2s orbitals from different atoms; written as 1s or 2s. – Two 2p z orbitals from different atoms (axial overlap); written as 2p z.(Some sources say 2 px orbitals?) Pi ( ) MO: form from combinations of: –Two 2p x or 2p y orbitals from different atoms; written as 2p x or 2p y. –Do not appear until B 2 molecule
MO s from Atomic p-Orbital Combinations P orbitals can interact with each other forming either sigma molecular orbitals, 2p, in a end-to-end overlap or pi molecular obrbitals, p, in a side-to-side overlap. The order of energy for MO s derived from 2p orbitals is 2p < p < p* < 2p* There are three perpendicular p orbitals, so two sigma p orbitals (one bonding and one antibonding) and four pi p orbitals (two bonding and two antibonding) are formed. This energy order gives the expected MO diagram for most of the p-block elements for homonuclear diatomic molecules.
MO s for B, C and N The energy order of p orbitals results from the assumption that since s and p orbitals have differences in energy, they do not interact with each other. (or mix) However, when 2p atomic orbitals are half filled, such as in B, C and N, the repulsions between e are little and the energy of these p orbitals is not much different than the s atomic orbital, which leads to s and p orbital mixing. This mixing lowers the energy of the 2s bonding and antibonding orbitals and increases the energy of sigma 2p (bonding and antibonding) orbitals.The pi 2p orbitals are not affected. This mixing gives a different energy order: 2s < 2s* < p < 2p < p* < 2p
*MO diagrams for “< O 2 ” Resulting MO for diatomic molecules with < 16 e- (B 2, C 2, N 2, etc.) Bond order = ½ (# bonding e - - # antibonding e - ) B.O. (N 2 ) = ½ (10 – 4) = 6 / 2 = 3 (triple bond) N 2 has no unpaired electrons which makes it diamagnetic. N atom
*MO diagrams for “≥ O 2 ” Resulting MO for diatomic molecules with ≥ 16 e- (like O 2, F 2, Ne 2, etc.) O atom Bond order = ½ (# bonding e - - # antibonding e - ) B.O. (O 2 ) = ½ (10 – 6) = = 2 (double bond) O 2 has unpaired electrons which makes it paramagnetic.
Liquid N 2 and liquid O 2 From U. Illinois: http://www.chem.uiuc.edu/clcwebsite/liquido2.html N2N2 O2O2
Magnetism In an element or compound: Diamagnetism: all e - paired; no magnetic properties Paramagnetism: at least 1 unpaired e - – * Drawn into exterior magnetic field since spins of atoms become aligned; unlikely to retain alignment when field is removed Ex:NO ScMn O 2 * Ferromagnetism: occurs primarily in Fe, Co, Ni – Drawn into exterior magnetic field since spins of atoms become aligned; very likely to retain alignment when field is removed (i.e., “a permanent magnet”) – Nd 2 Fe 14 B is very ferromagnetic | <urn:uuid:313dc065-d095-42f5-b981-d577c5f4cc5b> | 3.296875 | 4,774 | Truncated | Science & Tech. | 70.173809 | 95,515,746 |
With so many silly gaits to choose from, why have we adopted so few?
Despite having the bones and muscles to perform a variety of gaits, human beings have developed an overwhelming preference for just two: walking and running. Now, computer analysis that allows simulation of infinite two-legged locomotions has shown our favored modes of bi-pedal travel use the least amount of energy.
Indeed, in an article published in the current online edition of the British journal Nature, Cornell engineers Andy Ruina and Manoj Srinivasan compare the mechanics of walking and running with "many other strange and unpractised gaits." They used a set of computer models that simulated physical measurements such as leg length, force, body velocity and trajectory, forward speed and work.
"We wish to find how a person can get from one place to another with the least muscle work," they report. "Why do people not walk or even run with a smooth level gait, like a waiter holding two cups brim-full of boiling coffee?"
The engineers' computer simulations conclude that walking is simply most energy efficient for travel at low speeds, and running is best at higher speeds. And, they report, a third walk-run gait is optimal for intermediate speeds, even though humans do not appear to take advantage of it.
The findings help to explain why the possible--but preposterous--gaits in the Monty Python sketch, "Ministry of the Silly Walks," have never caught on in human locomotion. The researchers add that extensions of this work might improve the design of prosthetic devices and energy-efficient bipedal robots.
Explore further: In China, yellow robots deliver snacks to your home | <urn:uuid:eb0f6e09-9607-46a9-8577-1a64359e59e7> | 3.375 | 350 | News Article | Science & Tech. | 35.592422 | 95,515,754 |
Материал из Антэкология /// Anthecology
Partial preference of insects for the male flowers of an annual herb
The flowers of the annual herb Impatiens capensis have distinct male and female phases. The male phase lasts four times as long as the female phase, and male flowers contain about 50% more nectar than female flowers. This suggests that the bulk of allocation to the flower is designed to ensure the dispersal of pollen rather than the fertilization of ovules. Honeybees, wasps and bumble bees all land on male flowers more often than would be expected by chance, and, having landed, wasps and bumble bees are more likely to enter a male flower than a female flower. The frequency of male flowers in the diet therefore exceeds their frequency in the population. This preference, although strong and consistent, is only partial, since some female flowers are included in the diet. We propose two hypotheses to account for the observed partial preference, the first based on competition between bees for flowers, and the second asserting that the bees detect nectar levels directly without using floral gender as a cue. The results of an experiment in which the most obvious gender cue, the androecium, was removed are consistent with the second hypothesis. | <urn:uuid:af96e16e-2ec7-417f-8c9c-93ff98bf0718> | 3.09375 | 274 | Academic Writing | Science & Tech. | 33.44144 | 95,515,767 |
Projected climate change could trigger massive range contractions among amphibian and reptile species in the southwest of Europe, according to a new study published in the Journal of Biogeography.
Araújo et al. projected distributions of 42 amphibian and 66 reptile species 20-50 years into the future under four emission scenarios proposed by the Intergovernmental Panel on Climate Change and two different climate models (HadCM3 and CSIRO2). The researchers found that increases in temperature are not likely to constitute a major threat to amphibian and reptile species in Europe. Indeed, a global cooling scenario would be much worse.
However, increases in aridity could trigger contractions in the distributions of nearly all species occurring in the southwest of Europe, including Portugal, Spain and France. Impacts in these three countries are not trivial because, together, they hold 62% of the amphibian and reptile species present in Europe.
The high proportion of amphibian and reptile species occurring in these three countries is due to the key role played by the Iberian Peninsula as refugia against extinctions during past glacial periods. With projected climate changes 'these hotpots of persistence might be at risk of becoming hotspots of extinction', says Dr.Miguel Araújo.
Source: Blackwell Publishing Ltd
Explore further: Climate change to overtake land use as major threat to global biodiversity | <urn:uuid:b21ffe87-9a4f-4f18-a8dc-ad4ba96ec275> | 3.3125 | 282 | News Article | Science & Tech. | 25.111 | 95,515,771 |
Reef Recovery at Magnetic Island
A growing recognition that many reefs are showing signs of limited or slow recovery after recent disturbances, and the accumulating spatial extent of degradation of reefs, has led to increased interest in the potential for restoration to play a role in future management of the Great Barrier Reef (GBRMPA 2017).
Click HERE to access the Reef Recovery and Restoration Quiz
Like coral reefs all around the world, the Great Barrier Reef is experiencing a sustained decline in key indicators of condition (such as coral cover) due an accumulation of local and global pressures. This is being met by an intensification of management efforts, with a strong focus on increased investment in addressing local sources of stress, such as degraded water quality, overfishing and crown-of-thorns starfish outbreaks. Increasingly, scientists, government, industries and communities governments are advocating active habitat restoration methods (Anthony et al, 2017, GBRMPA 2017, TNC 2017) as a complement to stress-reduction programs to accelerate recovery of local reefs, and to involve local communities in stewardship activities.
Community, researchers, industry and government working together by sharing knowledge, monitoring and taking action to restore coral reefs to a healthy state around Magnetic Island by 2025
Reef Recovery on Magnetic Island is an innovative project in partnership with government, researchers, industry and community that aims to make a positive environmental, social and economic benefit for our local reefs and communities. The project activities focus on the manual removal of overgrowing, weedy macroalgal on the fringing reefs of Magnetic Island. Magnetic Island nearshore reefs are home to substantial seaweed, potentially greater than historical levels. Reef Ecologic’s research permits which allow controlled collection of a limited amount seaweed to allow future corals space to grow and for juvenile corals to settle. While macroalgae is crucial for reef health, too much of it can upset the fine ecological balance of coral reefs (see science below).
The project has environmental, social and economic benefits for the reef, community and industry. The potential environmental benefit of the Reef Recovery project are associated with improving future inshore coral reef health by removing seaweed.The seaweed we collect is measured and weighed and then taken to the Magnetic island Reef Guardian school for use as compost. The project aims to provide opportunities for visitors and the community to learn about and engage in inshore reef recovery and is an examples of positive stewardship where individuals and groups can make a difference at a local, reef and global scale.
The research is permitted at 3 locations at Magnetic island: Nelly Bay, Picnic Bay and Arthur Bay. We undertake research on the reef flat in 0.5 to 2m of water depth.
Magnetic Island is ideal as a site for this macroalgal removal experiment for a number of reasons. It is easily accessible for fieldwork, in most areas there is a dominance of macroalgae, and includes the opportunity for community, industry and tourism involvement.
Habitats and species
We undertake habitat research on coral and algae. The primary algae species is Sargassum spp. (a large brown algae which can grow to 2m in length) and Lobophora variegata (a small brown, ruffled, encrusting algae).
The research design investigates reef habitat at 3 locations, methods of removal of macroalgae (hand vs tool) and scale of removal (2m2 4m2 and 10m2 plots). The primary research methodology is a Before\After study using the GBRMPA Reef Health Impact Study methodology (GBRMPA 2012).
Coral cover on the fringing reefs of Magnetic Island has been relatively stable for the past 15 years while macroalgal cover has varied from 5 to 37% (Thompson et al. 2016). Anecdotal evidence suggests that Magnetic Island was once subject to significantly higher levels of water clarity and coral reefs around Magnetic Island have, in the past, supported high coral cover, despite high turbidity. Shallow reef flats and reef crests have always been subject to stands of Sargassum, but reef slopes below ~4 m were previously coral-dominated.
Our research indicates that the average cover of Sargassum at Nelly Bay in 2016 was 30% and in 2017 was 53%, an apparent increase of 23%. The average cover of macroalgae at Arthur Bay increased slightly from 45% to 46%, however average coral cover declined from 26 to 7%.
A pilot study for testing macroalgal reduction methodology at Magnetic Island was conducted in 2016 to test different removal methods. Different sizes research plots have also been compared beginning with 2m2 and scaling up to 4m2 and 10m2 plots in 2017. The project focusses on management outcomes including the development of a Standard Operation Procedure, partnerships, funding and communication.
Sargassum at Nelly Bay in 2017
Macroalgae at Arthur Bay
Social science is an integral part of the research with Dr Maria-Louise Bønnelykke conducting before-after attitude and perception surveys around reef knowledge, health and attitudes towards active involvement in reef restoration activities. Following involvement in the project, 95% of participants (up from 50% before participation) have shown a willingness to change their behaviour.
Education is a key element of the project. All participants are provided with background information and a thorough briefing on the project to ensure a comprehensive understanding of the ecosystems function, the role macroalgae plays in this system, and how a balanced approach to active restoration is required for successful outcomes. We also raise awareness about climate change issues at interpersonal levels, requesting participants to complete their ecological footprint (www.footprintnetwork.org) and encouraging change to reduce their individual impacts.
Reef Ecologic endeavour to educate all participants in three key areas:
- Knowledge (about people, sustainability, reef, restoration, research, risk assessment, communication),
- Field Research; and
- Communication; (with a particular focus on the RARE formula for change and conservation outcomes rare.org).
A positive story like the reef recovery project has the potential to inspire reef stakeholders around the world. Therefore, a key element of the project we provide is guidance on scientific communication, engaging students to develop and distribute their own communications pieces about their involvement in active reef restoration on the Great Barrier Reef. It is an empowering and rewarding process that yields some sensational outcomes.
Follow the links below for examples:
Steamboat Mountain School – Reef Research Restoration at Magnetic Island – April 2016
Ohio State University – Reef Recovery May 2017
Great Barrier Reef Recovery on SciStarter
ABC News – Great Barrier Reef health could be improved with ‘seaweed tourism’
ABC News – ‘Reef recovery project’ off Townsville aims to protect coral and help health of the reef
World Ocean Day – Reef Recovery at Magnetic Island
Reef Recovery Presentation – Coastal Restoration Symposium, September 2017
Team, supporters and partners
GBRMPA (government) and Reef Ecologic (community)
Qld Fisheries, Sealink Queensland, Townsville LMAC, Magnetic island Reef Recovery Group , Bungalow Bay Koala Village
Reef Check, James Cook University, TOBMI, Reef HQ, Australian Institute of Marine Science (AIMS), Port of Townsville, Townsville Enterprise (TEL), Wulgarukaba traditional owners
Key Team Members:
Dr Adam Smith – Director, Reef Ecologic
Dr Daniela Ceccarelli – Marine Ecology Consultant
Andrew Skeat – retired General Manager, GBRMPA
Brett Flemming – Manager, Bungalow Bay Koala Village
Dr Maria-Louise Bønnelykke – Social Scientist, CSIRO
Nathan Cook – Senior Marine Scientist, Reef Ecologic
The project was established through partnerships with the Great Barrier Reef Marine Park Authority, Queensland Department of Primary Industries and SeaLink Queensland to determine strategic and operational objectives, permits and reporting. We work closely with academic bodies including James Cook University and the Australian Institute of Marine Science so that our research is mutually beneficial and there is no negative impact or overlap with existing research sites. The Reef Recovery team work closely with a broad cross-section of the community including the Townsville Local Marine Advisory Committee and the Wulgurukaba traditional owners. We have worked closely with edu-tourism interests including Reef HQ, Sealink Qld, Bungalow Bay Koala Village and Magnetic Island Tourism on the links with education, research and tourism. The Reef Recovery team have recently established a partnership with Port of Townsville to focus on research and sustainability of marine environments. At an international level we engage with AUIP Study Abroad programs and American universities to share knowledge, make a difference and change behaviour so that we are all more sustainable.
How can you get involved
Successful reef recovery projects are long-term commitments. There is potential for reef recovery and reef restoration practices from this project at Magnetic island to be scaled-up and used widely by government, scientists, tourism, industry and citizen science to benefit other Queensland communities as well as Australia and international coral reefs. Individuals and groups currently participate by signing on as research assistants for their visit. Reef Ecologic currently works with AUIP Study Abroad program groups who participate in the reef recovery project. We also conduct community events where anyone can get involved and help improve the health of Magnetic Island’s nearshore reefs. These are usually held in conjunction with annual events such as World’s Oceans Day or Reef Check’s annual Reefblitz events. Check out Reef Ecologic’s Facebook page for upcoming event dates and locations.
Despite lofty emissions targets and pledges by the international community, scientists predict that the effects of climate change are likely to get worse before any improvement is realised. Consequently, the next generation is in line to inherit natural ecosystems in a much poorer, and declining state than present, potentially requiring drastic action to support reef resilience and ecosystem health.Read More
In December 2017, Reef Ecologic were instrumental in supporting the Reef Restoration Foundation in the establishment of the first coral nurseries on the Great Barrier Reef at Fitzroy Island, Cairns In collaboration with a team of volunteers, local businesses, organisations and researchers established the first coral nursery on the Great Barrier Reef.Read More
A growing recognition that many reefs are showing signs of limited or slow recovery after recent disturbances, and the accumulating spatial extent of degradation of reefs, has led to increased interest in the potential for restoration to play a role in future management of the Great Barrier Reef (GBRMPA 2017).Read More
For the last three years Reef Ecologic have been commissioned by the Australian Government Department of Foreign Affairs and Trade (DFAT) to coordinate the International Coral Reef Management and Leadership Course. The Course has been designed by world experts on Coral reef management and leadership to equip the participants with knowledge, skills, experiences, case studies and inspirational stories about coral reefs and people.Read More
Anthony, K., Bay, L.K., Costanza, R., Firn, J., Gunn, J., Harrison, P., Heyward, A., Lundgren, P., Mead, D., Moore, T. and Mumby, P.J., 2017. New interventions are needed to save coral reefs. Nature Ecology & Evolution, 1(10), p.1420.
Aronson, J., Alexander, S. (2013). Ecosystem restoration is now a global priority: Time to roll up our sleeves. Restoration Ecology. News Report from CBD COP11.
GBRMPA (2012). Reef Health and Impact Survey
Maggini, R., Kujala, H., Taylor, M.F.J., Lee, J.R., Possingham, H.P., Wintle, B.A., Fuller, R.A. (2013). Protecting and restoring habitat to help Australia’s threatened species adapt to climate change, National Climate Change Adaptation Research Facility, Gold Coast, 54 pp.
Thompson, A., P. Costello, J. Davidson, M. Logan, G. Coleman, K. Gunn, and B. Schaffelke. 2016. Marine Monitoring Program. Annual Report for inshore coral reef monitoring: 2014 to 2015. Report for the Great Barrier Reef Marine Park Authority. Australian Institute of Marine Science, Townsville.133 pp. | <urn:uuid:e5131040-5465-4d8d-b38e-965c21a4efa5> | 3.03125 | 2,537 | About (Org.) | Science & Tech. | 31.281418 | 95,515,813 |
Many more are put at risk in a worst-case scenario of the combined impacts on crop yields, water availability, ecosystems, and health, according to a study now published online by the Proceedings of the National Academy of Sciences (PNAS).
It identifies the Amazon region, the Mediterranean and East Africa as regions that might experience severe change in multiple sectors. The article is part of the outcome of the Intersectoral Impact Model Intercomparison Project (ISI-MIP) that will be featured in a special issue of PNAS later this year.“Overlapping impacts of climate change in different sectors have the potential to interact and thus multiply pressure on the livelihoods of people in the affected regions,” says lead-author Franziska Piontek of the Potsdam Institute for Climate Impact Research. “This is why we focus on multisectoral impacts around the world, which turn out to be felt in developed as well as developing countries.”
Jonas Viering | PIK Potsdam
Scientists discover Earth's youngest banded iron formation in western China
12.07.2018 | University of Alberta
Drones survey African wildlife
11.07.2018 | Schweizerischer Nationalfonds SNF
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
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13.07.2018 | Life Sciences | <urn:uuid:bcca127a-f73b-4d3f-b436-cebb88500b9d> | 2.984375 | 832 | Content Listing | Science & Tech. | 38.276972 | 95,515,832 |
Bildtext får vara max två rader text. Hela texten ska högerjusteras om den bara ska innehålla fotobyline! Photo: B. Christensen/Azote
A recent article, Montoya et al., in the journal Trends in Ecology and Evolution is based on a fundamental misrepresentation of the Planetary Boundaries framework.
Their representation of the framework is directly contradicted in all of the papers presenting the planetary boundaries framework (Rockström et al, 2009a; 2009b; Steffen et al., 2015). What’s more, Montoya et al. repeat earlier misrepresentations of the research. Thus, it would appear that Montoya et al. derived their understanding of the planetary boundaries framework from secondary, rather than primary, sources.
We are surprised that the discrepancy between the Montoya et al. representation of the planetary boundaries and that presented in the primary literature was not picked up in peer review.
We note as well that the tone of the Montoya et al. contribution is unusually normative and personal, thus undermining its potential value as a constructive contribution to an important scientific debate. The paper presents a vitriolic and opinionated critique on the Planetary Boundaries framework and in particular the biodiversity (biosphere integrity) boundary. All of this is unfortunate as Montoya et al. make many valid points with which we are in agreement in their discussion of biodiversity challenges at the local and regional level.
Briefly, Montoya et al. conflate tipping points with planetary boundaries with such claims as:
"How best should environmental science articulate its concerns, set research agendas, and advise policies? One solution embraces the notion of planetary boundaries arguing that global environmental processes very generally have ‘tipping points’. These are catastrophes involving thresholds beyond which there will be rapid transitions to new states that are very much less favorable to human existence than current states."
"The rate of human-caused extinction…is one of two of the nine global processes deemed to have exceeded a purported tipping point."
These statements are blatantly incorrect. Any author or reviewer who has read the primary Planetary boundaries literature would know this to be the case. Steffen et al. (2015), for example, clearly state:
"A planetary boundary as originally defined is not equivalent to a global threshold or tipping point."
To build their case, Montoya et al. neglect this clear and unambiguous statement, which forms the basis of the theoretical framework and thus runs systematically right through the entire analysis of defining and quantifying planetary boundaries.
We find it surprising that the Montoya et al. Forum piece includes the same misrepresentation as the Breakthrough Institute’s error-filled 2012 article (published to coincide with the UN Rio+20 conference) (Blomqvist et al., Breakthrough Institute 2012), to which we replied by explaining, just as now, the fundamental misrepresentation of the framework.
We also find it surprising that the referees did not pick up on Montoya et al.’s reliance on highly selective statements from a talk given by Rockström at the World Economic Forum in 2017 in support of their critique. This talk is both an extremely unusual reference in the peer-reviewed literature and completely irrelevant to the arguments made in the Montoya et al. paper. The statements made in the talk had (1) nothing to do with the Planetary Boundaries framework, and (2) say nothing about biodiversity-related tipping points.
In the following we offer a brief correction of the misrepresentations in Montoya et al., and close by making clear that their speculation on the policy implications of adopting a planetary boundaries framework is nothing more than their own personal opinions.
In support of this statement we will also publish a full response in TREE.
20 November 2017,
The environmental processes selected for inclusion in the planetary boundaries framework are those that are known to contribute to regulating the Earth System, i.e. operate at a planetary level. Some of these processes (for example climate through ice melt) are known to exhibit threshold or “tipping point” behavior. However, most – including biodiversity/biosphere integrity – are assumed not to (see Figure 4, Rockström et al 2009b and Steffen et al, 2015). Even in the few cases where the scientific evidence supports threshold behavior, the identified planetary boundaries are not placed at the estimated point (for a control variable) of a threshold.
The existence (or otherwise) of thresholds and/or “tipping point” behaviour in the processes included is thus not a pre-assumption or requirement to the planetary boundaries framework.
Montoya et al’s critique is founded on a deep misunderstanding of the Planetary Boundaries framework. In the Planetary Boundaries research, we have never claimed that there is a planetary scale biodiversity tipping point. Furthermore, the Planetary Boundary framework does not state that any global processes have exceeded tipping points (See Steffen et al., 2015).
We include biodiversity (in the latest scientific update, Steffen et al., 2015, defined as biosphere integrity to emphasise the functional and regulatory role of biodiversity for ecosystem stability) as a planetary boundary on the scientific ground that the biosphere interacts with the climate system, hydrological cycle and other biogeochemical cycles in the Earth system, and thereby contributes to the regulation of the state of the Earth system.
Furthermore, for most of the long history of the Earth system, the geosphere and biosphere have co-evolved as a single, interacting system, emphasising the very important role that the biosphere plays in the stability of the Earth system as a whole (Lenton 2015).
Based on this evidence, therefore, the inclusion of biodiversity as a planetary boundary is justified by the aggregate and interacting role of biomes in regulating the stability of the Earth system, a role that at smaller scales is evidenced by the role it plays in ecosystem stability. This, as stated by Montoya et al., is their focus as well. So, in essence, we are in agreement - biodiversity contributes to the regulation of the stability of ecosystems and consequently aggregates across scales to the Earth system as a whole.
The Planetary Boundaries framework thus provides a complement to the myriad methods and approaches for ecosystem management [not least as advocated by Montoya et al.], by attempting to provide an Earth system-level framing. As specifically pointed out in Steffen et al., 2015, the planetary boundaries approach is not intended as a replacement for ecosystem management approaches but a complement that takes Earth system considerations into consideration.
The Planetary Boundaries framework has never been proposed as a panacea to replace all the necessary and important approaches, from conservation policies, payment schemes for ecosystem services to marine protected areas and Aichi targets.
The Planetary Boundaries framework evolved from the major advancements in Earth system science over four decades, ranging from evidence and insights on the Anthropocene (Steffen et al. 2016), tipping elements in the Earth system (Lenton et al. 2008), ecological resilience (Folke et al. 2004), multiple stable states in biomes (Scheffer 2009) and the biosphere-geosphere regulatory interactions noted above (Lenton 2015).
The first publication of the Planetary Boundaries framework in 2009 was followed by a deep peer-reviewed scrutiny, e.g., those by Carpenter and Bennett (2011) and deVries et al. (2013) on the biogeochemical flows boundary.
We welcome this scientific critique, which has improved the Planetary Boundaries definitions and the assessment of quantitative boundary levels for control variables.
There is rising scientific evidence that planetary stewardship is required to enable a sustainable future for humanity on Earth in the Anthropocene (e.g., Folke et al. 2016). While action, methods, policies, investments and management occur locally and across scales, in the Anthropocene, due to the planetary scale of human pressures on the Earth system, this all must add up at the Earth system level. Just as all countries need to decarbonise energy systems by 2050-2060 to "add-up" within a climate planetary boundary of 1.5 degrees Celsius, there is evidence that biomes, from rainforests to coral reefs to tundra/permafrost, need to remain stable to enable world development on a planet that remains reasonably stable in something resembling an interglacial state.
The Planetary Boundaries framework offers, for the first time, an attempt to identify all the critical, interacting processes on Earth that contribute to the stability and resilience of the Earth system as a whole. This draws on the best knowledge we have today on the quantitative boundaries within which we are likely to remain in (or return to) a Holocene-like state, but beyond which we are at increasing risk of eliminating that possibility.
As such, the Planetary Boundaries framework offers an attempt to define biophysical science-based targets at the Earth system level as a response to humanity now being in the Anthropocene. As emphasized in the Steffen et al (2015) paper, the Planetary Boundaries framework should be seen as a complement – and not a competitor – to ecosystem and other sustainability management principles and methods developed, and effectively adapted, for different scales and sectors.
Today, Planetary Boundaries provide scientific support for an integrated Earth system approach to global sustainability, integrating, e.g., biosphere sustainability with climate mitigation. It provides a framework for defining science-based global targets that go beyond "CO2 only", to include biodiversity, nitrogen, phosphorus, water, and land, i.e., biosphere functioning.
It is, in short, an Earth system-level framework that builds upon and supports sustainable development and ecosystem management across scales. It does not replace them.
Montoya et al. question whether there are any thresholds associated with biodiversity in ecosystems altogether with their statement “neither theory nor empirical data support any threshold of biodiversity below which ecosystem function is compromised”.
This contradicts the scientific evidence. Again, if the authors had followed the literature and the advancements in planetary boundaries research, they would have followed the exchange in 2012, where Brook et al. 2013 questioned whether there is a planetary scale tipping point in the terrestrial biosphere (i.e., exactly the same misinterpretation as Montoya et al. in 2017).
Moreover, this misrepresentation was also published in TREE.
Hughes et al., (2013) answered this misguided critique by (1) making it clear that the Planetary Boundaries framework has never claimed to postulate a planetary-level biosphere tipping point; (2) presenting clearly the scientific evidence that there are multiple stable states in ecosystems, i.e., biodiversity-coupled tipping points in ecosystems (which Montoya et al. claim do not exist); and (3) summarizing some of the emerging scientific literature suggesting that there may, after all, be a planetary scale biodiversity tipping point (as suggested by Barnosky et al. 2012).
So, fundamentally, Montoya et al., trod down old ground, subsequently discussed in much more detail in the scientific literature. It is a disappointment that the same misrepresentations and unfounded aggressive critique resurface five years later and in the same journal.
This discussion notwithstanding, whether or not biodiversity/ecosystems exhibit threshold responses is immaterial to the Planetary Boundaries framework. Indeed, Steffen et al. (2015) explicitly state that change in biosphere integrity is one of planetary boundary processes assumed not to have a singular threshold at the global or continental/ocean-basin level.
Anyone who has carefully studied the planetary boundary literature can, therefore, be in no doubt that there is absolutely no expectation of a “tipping point” or a “threshold” with respect to biodiversity/biosphere integrity implicit in the framework.
Montoya et al. make an unsubstantiated claim that the planetary boundaries framework potentially leads to perverse policy. Incredulously, they seem to be of the opinion that adopting Planetary Boundaries lowers ambitions towards global sustainability, and once the world succeeds in transitioning into the biophysical "safe operating space" within planetary boundaries, the world would lean back and return to unsustainable business-as-usual practices:
"…the planetary boundary framework suggests that we can view nature and its complex ecological processes as a type of blackbox – if we do not poke it too hard, we will not need to understand its details. We need not define measures, terms, processes, responses in operational ways. In short, ecological ignorance is bliss, if human actions remain within limits."
This is an astonishing and clearly a personal opinion held by the authors. The biodiversity (biosphere integrity) boundary is positioned at <10 extinctions/million species per year. We are today at a rate of extinctions 10 - 100 times higher. Returning to a safe operating space for biodiversity will require a major transformation in ecosystem management across all land-based and marine ecosystems across the world.
Once the world returns into a safe operating space for biodiversity [let’s assume we succeed!], is it likely [or even possible] that the Planetary Boundaries framework will encourage some form of "ecological ignorance" and unsustainable use of ecosystems? Of course not.
Transforming societies back to within the safe operating space of planetary boundaries, for all boundaries, requires adoption of sustainable practices that - once on safe ground - obviously need to be sustained to remain sustainable. Take, for example, the stratospheric ozone boundary, where the world transgressed the boundary in the late 1980s but has returned back to within the safe operating space through global concerted implementation of the Montreal Protocol, phasing out ozone depleting substances, and has remained anchored in this new social state.
And, honestly, if Montoya et al. were right, why would this bizarre assumption (that sustainable management is suddenly abandoned once sustainable targets are met) not apply to the CBD and the Aichi targets which Montoya et al. applaud as a much more concrete and adequate way forward toward ecosystem management?
Meeting the Aichi targets is, evidently, a much less ambitious task than meeting the planetary boundary on biodiversity. It is though, interestingly (given that Montoya et al. applaud it so strongly as concrete while critiquing the Planetary Boundaries as vague and dangerous for policy), set almost exactly in the same way as the planetary boundary.
Setting aside 17% of land area and 10% of the ocean as protected areas are global quantitative targets very similar to the combined land and biodiversity boundaries of safeguarding a minimum of 75% of critical forest biomes and reducing extinction rates to below 10 extinctions/million species per year. The implication of these Planetary Boundaries is essentially that we need to ensure zero or close to zero future expansion of agricultural land, i.e., ensure that 50 % of land area remains as natural ecosystems [given that we have already transformed ~40-50 % to agricultural land], which is several magnitudes more challenging than meeting the Aichi targets [setting aside 17 % of land-based ecosystems].
So, in the Montoya et al. projection of the future, we would meet the Aichi targets well before the planetary boundary on biodiversity. But what happens once we meet the Aichi targets?
If the world, according to Montoya et al., leans back and does nothing once the planetary boundary is met, what hinders the world to do the same once the Aichi targets are met, moreover, much earlier? Of course, this is not going to happen. If the Aichi targets are met, continued conservation of ecosystems is needed to remain on the "right side" of Aichi.
The same applies to the planetary boundaries.
Carpenter, S., E.M. Bennett, Environ. Res. Lett. 6, doi:10.1088/1748-9326/6/1/014009 (2011)
Carpenter S.R., and R. Biggs. 2009. Freshwaters: managing across scales in space and time. Pages 197-220 in: Principles of Ecosystem Stewardship: Resilience-Based Natural Resource Management in a Changing World. F.S .Chapin, III, G.P. Ko nas, and C. Folke, edi- tors. Springer, New York
de Vries et al., W.. Curr. Opinion Environ. Sust. 5, 392 (2013)
Folke, C., S. R. Carpenter, B. Walker, M. Scheffer, T. Elmqvist, L. Gunderson, and C. S. Holling. 2004. Regime shifts, resilience,and biodiversity in ecosystem management. Annual Review of Ecology, Evolution and Systematics 35:557-581. http://dx.doi.org/10.1146/annurev.ecolsys.35.021103.105711
Folke C, Biggs R, Norström AV, Reyers B, Rockström J (2016) Social-ecological resilience and biosphere-based sustainability science. Ecol. Soc. 21:41
Hughes, T.P., Kerry, J.T., and Wilson, S.K., 2017. Global warming and recurrent mass bleaching of corals. Nature 543, 373-377
Lenton TM (2015) Earth System Science. A Very Short Introduction. Oxford, Oxford University Press, 153 pp.
Lenton TM, et al. (2008) Tipping elements in Earth’s climate system. Proc Nat. Acad. Sci USA 105:1786-1793
Rockström et al. Nature. 461: 472-475 (2009a)
Rockström et al., Ecology and Society, 14(2): 32 (2009b)
Scheffer M (2009) Critical Transitions in Nature and Society, Princeton University Press.
Scheffer, M. and Carpenter, S.R. (2003) Catastrophic regime shifts in ecosystems: linking theory to observation. Trends Ecol. Evol. 18, 648– 656
Steffen et al. Vol. 347, Issue 6223, 1259855 DOI: 10.1126/science.1259855 10.1126 (2015)
Steffen W, et al. (2016) Stratigraphic and Earth System approaches to defining the Anthropocene. Earth's Future 4: doi: eft2/2016EF000379
The planetary boundaries concept presents a set of nine planetary boundaries within which humanity can continue to develop and thrive for generations to come.
The framework was first introduced in 2009, when a group of 28 internationally renowned scientists identified and quantified the first set of nine planetary boundaries within which humanity can continue to develop and thrive for generations to come.
In January 2015, an update was published in Science. It revealed that an additional boundary had been crossed, land-system change, consequently leaving four out of nine borders crossed.
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New book chapter looks into the economic, cultural and ecological reasons why some people leave the fisheries and aquaculture sector, and what could be done to reverse the trend | <urn:uuid:f802308e-11f9-44af-a431-444df676d5e2> | 2.578125 | 4,134 | Academic Writing | Science & Tech. | 36.48515 | 95,515,839 |
A transformer is an electrical device that can change the voltage from one value to another, based on the principle of Faraday's Law of Induction. Consider a transformer with Np turns of wire in the primary (input) circuit and Ns turns in the secondary (output). Which of the following statements are true? Briefly justify your answers.
1. Transformers can only work with DC voltages (not AC).
2. If the secondary voltage is lower than the primary voltage, then the secondary current is also lower than the primary current.
3. To have a higher voltage on the secondary, Ns < Np.
4. Transformers in your neighborhood step up the voltage from power plants so that there is plenty of electricity to run your many home appliances.
5. If Ns > Np, the average power in the secondary is greater than the average power in the primary.© BrainMass Inc. brainmass.com July 18, 2018, 3:08 am ad1c9bdddf
1. False. Transformer works on the principle of induced emf in a coil placed in a varying magnetic field. In case of DC, the current does not vary, hence there is no varying magnetic field, hence no induced emf. In case of AC there is a varying magnetic field on account of ...
This solution provides answers to the true and false questions about transformers with an explanation for each. | <urn:uuid:4d2696ba-2fdc-4ebc-a68f-dd440d7e8a43> | 3.984375 | 292 | Q&A Forum | Science & Tech. | 63.663452 | 95,515,854 |
Can you explain the importance of Record Reader in Hadoop?
It is a class which actually loads the data from source. Mapper always understands key value pair, so record reads line by line from input split and converts it into key value pair for the mapper. It is invoked repeatedly on the input until the entire split is consumed. On each invocation of record reader leads to another call of map function defined by the programmer. The record reader instance is defined by the input format.
Pretty good, but you need to point out that its not necessarily a single line. You can have multiple lines in a single record. A good example of this is if you're using XML or JSON to represent the record. God I'm going from memory, but you'd have to overload the input record format and this could also include extending the multi-line input format so that you can capture a single record for processing.
Its also important to note that your single Mapper task will read at most 2 splits. The record reader will skip bytes until it finds the start of a record, and if the record exceeds the end of the current split, it will read into the next split to finish reading the record.
Retrieving data ... | <urn:uuid:6ac5c5d4-6a59-47bd-9d13-fc53b813919a> | 2.703125 | 248 | Q&A Forum | Software Dev. | 63.377644 | 95,515,873 |
In physics, buoyancy (/ˈbɔɪ.ənsi, ˈbuːjən-/) or upthrust, is an upward force exerted by a fluid that opposes the weight of an immersed object. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus the pressure at the bottom of a column of fluid is greater than at the top of the column. Similarly, the pressure at the bottom of an object submerged in a fluid is greater than at the top of the object. This pressure difference results in a net upwards force on the object. The magnitude of that force exerted is proportional to that pressure difference, and (as explained by Archimedes' principle) is equivalent to the weight of the fluid that would otherwise occupy the volume of the object, i.e. the displaced fluid.
For this reason, an object whose density is greater than that of the fluid in which it is submerged tends to sink. If the object is either less dense than the liquid or is shaped appropriately (as in a boat), the force can keep the object afloat. This can occur only in a non-inertial reference frame, which either has a gravitational field or is accelerating due to a force other than gravity defining a "downward" direction. In a situation of fluid statics, the net upward buoyancy force is equal to the magnitude of the weight of fluid displaced by the body.
The center of buoyancy of an object is the centroid of the displaced volume of fluid.
Archimedes' principle is named after Archimedes of Syracuse, who first discovered this law in 212 B.C. For objects, floating and sunken, and in gases as well as liquids (i.e. a fluid), Archimedes' principle may be stated thus in terms of forces:
Any object, wholly or partially immersed in a fluid, is buoyed up by a force equal to the weight of the fluid displaced by the object
— with the clarifications that for a sunken object the volume of displaced fluid is the volume of the object, and for a floating object on a liquid, the weight of the displaced liquid is the weight of the object.
More tersely: Buoyancy = weight of displaced fluid.
Archimedes' principle does not consider the surface tension (capillarity) acting on the body, but this additional force modifies only the amount of fluid displaced and the spatial distribution of the displacement, so the principle that Buoyancy = weight of displaced fluid remains valid.
The weight of the displaced fluid is directly proportional to the volume of the displaced fluid (if the surrounding fluid is of uniform density). In simple terms, the principle states that the buoyancy force on an object is equal to the weight of the fluid displaced by the object, or the density of the fluid multiplied by the submerged volume times the gravitational acceleration, g. Thus, among completely submerged objects with equal masses, objects with greater volume have greater buoyancy. This is also known as upthrust.
Suppose a rock's weight is measured as 10 newtons when suspended by a string in a vacuum with gravity acting upon it. Suppose that when the rock is lowered into water, it displaces water of weight 3 newtons. The force it then exerts on the string from which it hangs would be 10 newtons minus the 3 newtons of buoyancy force: 10 − 3 = 7 newtons. Buoyancy reduces the apparent weight of objects that have sunk completely to the sea floor. It is generally easier to lift an object up through the water than it is to pull it out of the water.
Assuming Archimedes' principle to be reformulated as follows,
then inserted into the quotient of weights, which has been expanded by the mutual volume
yields the formula below. The density of the immersed object relative to the density of the fluid can easily be calculated without measuring any volumes.:
Example: If you drop wood into water, buoyancy will keep it afloat.
Example: A helium balloon in a moving car. During a period of increasing speed, the air mass inside the car moves in the direction opposite to the car's acceleration (i.e., towards the rear). The balloon is also pulled this way. However, because the balloon is buoyant relative to the air, it ends up being pushed "out of the way", and will actually drift in the same direction as the car's acceleration (i.e., forward). If the car slows down, the same balloon will begin to drift backward. For the same reason, as the car goes round a curve, the balloon will drift towards the inside of the curve.
The equation to calculate the pressure inside a fluid in equilibrium is:
where f is the force density exerted by some outer field on the fluid, and σ is the Cauchy stress tensor. In this case the stress tensor is proportional to the identity tensor:
Here δij is the Kronecker delta. Using this the above equation becomes:
Assuming the outer force field is conservative, that is it can be written as the negative gradient of some scalar valued function:
Therefore, the shape of the open surface of a fluid equals the equipotential plane of the applied outer conservative force field. Let the z-axis point downward. In this case the field is gravity, so Φ = −ρfgz where g is the gravitational acceleration, ρf is the mass density of the fluid. Taking the pressure as zero at the surface, where z is zero, the constant will be zero, so the pressure inside the fluid, when it is subject to gravity, is
So pressure increases with depth below the surface of a liquid, as z denotes the distance from the surface of the liquid into it. Any object with a non-zero vertical depth will have different pressures on its top and bottom, with the pressure on the bottom being greater. This difference in pressure causes the upward buoyancy force.
The buoyancy force exerted on a body can now be calculated easily, since the internal pressure of the fluid is known. The force exerted on the body can be calculated by integrating the stress tensor over the surface of the body which is in contact with the fluid:
The surface integral can be transformed into a volume integral with the help of the Gauss theorem:
where V is the measure of the volume in contact with the fluid, that is the volume of the submerged part of the body, since the fluid doesn't exert force on the part of the body which is outside of it.
The magnitude of buoyancy force may be appreciated a bit more from the following argument. Consider any object of arbitrary shape and volume V surrounded by a liquid. The force the liquid exerts on an object within the liquid is equal to the weight of the liquid with a volume equal to that of the object. This force is applied in a direction opposite to gravitational force, that is of magnitude:
If this volume of liquid is replaced by a solid body of exactly the same shape, the force the liquid exerts on it must be exactly the same as above. In other words, the "buoyancy force" on a submerged body is directed in the opposite direction to gravity and is equal in magnitude to
The net force on the object must be zero if it is to be a situation of fluid statics such that Archimedes principle is applicable, and is thus the sum of the buoyancy force and the object's weight
If the buoyancy of an (unrestrained and unpowered) object exceeds its weight, it tends to rise. An object whose weight exceeds its buoyancy tends to sink. Calculation of the upwards force on a submerged object during its accelerating period cannot be done by the Archimedes principle alone; it is necessary to consider dynamics of an object involving buoyancy. Once it fully sinks to the floor of the fluid or rises to the surface and settles, Archimedes principle can be applied alone. For a floating object, only the submerged volume displaces water. For a sunken object, the entire volume displaces water, and there will be an additional force of reaction from the solid floor.
In order for Archimedes' principle to be used alone, the object in question must be in equilibrium (the sum of the forces on the object must be zero), therefore;
showing that the depth to which a floating object will sink, and the volume of fluid it will displace, is independent of the gravitational field regardless of geographic location.
It can be the case that forces other than just buoyancy and gravity come into play. This is the case if the object is restrained or if the object sinks to the solid floor. An object which tends to float requires a tension restraint force T in order to remain fully submerged. An object which tends to sink will eventually have a normal force of constraint N exerted upon it by the solid floor. The constraint force can be tension in a spring scale measuring its weight in the fluid, and is how apparent weight is defined.
If the object would otherwise float, the tension to restrain it fully submerged is:
When a sinking object settles on the solid floor, it experiences a normal force of:
Another possible formula for calculating buoyancy of an object is by finding the apparent weight of that particular object in the air (calculated in Newtons), and apparent weight of that object in the water (in Newtons). To find the force of buoyancy acting on the object when in air, using this particular information, this formula applies:
The final result would be measured in Newtons.
Air's density is very small compared to most solids and liquids. For this reason, the weight of an object in air is approximately the same as its true weight in a vacuum. The buoyancy of air is neglected for most objects during a measurement in air because the error is usually insignificant (typically less than 0.1% except for objects of very low average density such as a balloon or light foam).
A simplified explanation for the integration of the pressure over the contact area may be stated as follows:
Consider a cube immersed in a fluid with the upper surface horizontal.
The sides are identical in area, and have the same depth distribution, therefore they also have the same pressure distribution, and consequently the same total force resulting from hydrostatic pressure, exerted perpendicular to the plane of the surface of each side.
There are two pairs of opposing sides, therefore the resultant horizontal forces balance in both orthogonal directions, and the resultant force is zero.
The upward force on the cube is the pressure on the bottom surface integrated over its area. The surface is at constant depth, so the pressure is constant. Therefore, the integral of the pressure over the area of the horizontal bottom surface of the cube is the hydrostatic pressure at that depth multiplied by the area of the bottom surface.
Similarly, the downward force on the cube is the pressure on the top surface integrated over its area. The surface is at constant depth, so the pressure is constant. Therefore, the integral of the pressure over the area of the horizontal top surface of the cube is the hydrostatic pressure at that depth multiplied by the area of the top surface.
As this is a cube, the top and bottom surfaces are identical in shape and area, and the pressure difference between the top and bottom of the cube is directly proportional to the depth difference, and the resultant force difference is exactly equal to the weight of the fluid that would occupy the volume of the cube in its absence.
This means that the resultant upward force on the cube is equal to the weight of the fluid that would fit into the volume of the cube, and the downward force on the cube is its weight, in the absence of external forces.
This analogy is valid for variations in the size of the cube.
If two cubes are placed alongside each other with a face of each in contact, the pressures and resultant forces on the sides or parts thereof in contact are balanced and may be disregarded, as the contact surfaces are equal in shape, size and pressure distribution, therefore the buoyancy of two cubes in contact is the sum of the buoyancies of each cube. This analogy can be extended to an arbitrary number of cubes.
An object of any shape can be approximated as a group of cubes in contact with each other, and as the size of the cube is decreased, the precision of the approximation increases. The limiting case for infinitely small cubes is the exact equivalence.
Angled surfaces do not nullify the analogy as the resultant force can be split into orthogonal components and each dealt with in the same way.
A floating object is stable if it tends to restore itself to an equilibrium position after a small displacement. For example, floating objects will generally have vertical stability, as if the object is pushed down slightly, this will create a greater buoyancy force, which, unbalanced by the weight force, will push the object back up.
Rotational stability is of great importance to floating vessels. Given a small angular displacement, the vessel may return to its original position (stable), move away from its original position (unstable), or remain where it is (neutral).
Rotational stability depends on the relative lines of action of forces on an object. The upward buoyancy force on an object acts through the center of buoyancy, being the centroid of the displaced volume of fluid. The weight force on the object acts through its center of gravity. A buoyant object will be stable if the center of gravity is beneath the center of buoyancy because any angular displacement will then produce a 'righting moment'.
The stability of a buoyant object at the surface is more complex, and it may remain stable even if the centre of gravity is above the centre of buoyancy, provided that when disturbed from the equilibrium position, the centre of buoyancy moves further to the same side that the centre of gravity moves, thus providing a positive righting moment. If this occurs, the floating object is said to have a positive metacentric height. This situation is typically valid for a range of heel angles, beyond which the centre of buoyancy does not move enough to provide a positive righting moment, and the object becomes unstable. It is possible to shift from positive to negative or vice versa more than once during a heeling disturbance, and many shapes are stable in more than one position.
The atmosphere's density depends upon altitude. As an airship rises in the atmosphere, its buoyancy decreases as the density of the surrounding air decreases. In contrast, as a submarine expels water from its buoyancy tanks, it rises because its volume is constant (the volume of water it displaces if it is fully submerged) while its mass is decreased.
As a floating object rises or falls, the forces external to it change and, as all objects are compressible to some extent or another, so does the object's volume. Buoyancy depends on volume and so an object's buoyancy reduces if it is compressed and increases if it expands.
If an object at equilibrium has a compressibility less than that of the surrounding fluid, the object's equilibrium is stable and it remains at rest. If, however, its compressibility is greater, its equilibrium is then unstable, and it rises and expands on the slightest upward perturbation, or falls and compresses on the slightest downward perturbation.
Submarines rise and dive by filling large ballast tanks with seawater. To dive, the tanks are opened to allow air to exhaust out the top of the tanks, while the water flows in from the bottom. Once the weight has been balanced so the overall density of the submarine is equal to the water around it, it has neutral buoyancy and will remain at that depth. Most military submarines operate with a slightly negative buoyancy and maintain depth by using the "lift" of the stabilizers with forward motion.
The height to which a balloon rises tends to be stable. As a balloon rises it tends to increase in volume with reducing atmospheric pressure, but the balloon itself does not expand as much as the air on which it rides. The average density of the balloon decreases less than that of the surrounding air. The weight of the displaced air is reduced. A rising balloon stops rising when it and the displaced air are equal in weight. Similarly, a sinking balloon tends to stop sinking.
Underwater divers are a common example of the problem of unstable buoyancy due to compressibility. The diver typically wears an exposure suit which relies on gas-filled spaces for insulation, and may also wear a buoyancy compensator, which is a variable volume buoyancy bag which is inflated to increase buoyancy and deflated to decrease buoyancy. The desired condition is usually neutral buoyancy when the diver is swimming in mid-water, and this condition is unstable, so the diver is constantly making fine adjustments by control of lung volume, and has to adjust the contents of the buoyancy compensator if the depth varies.
If the weight of an object is less than the weight of the displaced fluid when fully submerged, then the object has an average density that is less than the fluid and when fully submerged will experience a buoyancy force greater than its own weight. If the fluid has a surface, such as water in a lake or the sea, the object will float and settle at a level where it displaces the same weight of fluid as the weight of the object. If the object is immersed in the fluid, such as a submerged submarine or air in a balloon, it will tend to rise. If the object has exactly the same density as the fluid, then its buoyancy equals its weight. It will remain submerged in the fluid, but it will neither sink nor float, although a disturbance in either direction will cause it to drift away from its position. An object with a higher average density than the fluid will never experience more buoyancy than weight and it will sink. A ship will float even though it may be made of steel (which is much denser than water), because it encloses a volume of air (which is much less dense than water), and the resulting shape has an average density less than that of the water.
Underwater diving portal | <urn:uuid:8330a794-94d4-46fe-9a8d-73a04e4081f7> | 4.03125 | 3,742 | Knowledge Article | Science & Tech. | 42.773617 | 95,515,874 |
A symbiotic relationship between species may be beneficial to both species, making it mutualistic. Relationships between species that do not benefit both members, but do not harm either one, are commensal. When one species is harmed by the other, the symbiosis is parasitic. Rhinoceroses experience both kinds of relationship. Their digestion depends on microflora in the gut, for example. Also, they attract insect parasites, which in turn attract birds who eat the insects. The rhinoceros enjoys relief from the insects, and the birds enjoy a meal, but the relationships are not always so simple.
Mutualistic Relationships in a Rhino's Gut
Rhinoceroses are ungulates -- hooved animals with digestive systems similar to horses and elephants. They eat tough plant matter but are not able to digest the cellulose their food contains. They rely on microflora that are able to digest this material, releasing nutrients like fatty acids that the host animal can absorb and use for energy. The hosts don't ruminate like cattle; the microflora work in the host's hindgut. Studies of white rhino dung have found bacteria called Firmicutes and Bacteroidetes dominating the microflora living in the rhino gut, along with many other unclassified bacteria.
A Symbiotic, but Parasitic, Relationship in a Rhino's Gut
The rhinoceros bot fly (Gyrostigma rhinocerontis) lives exclusively in the digestive tracts of both white and black rhinoceroses. The adults, which are the largest flies in Africa, lay their eggs on the skin of rhinos, and the larvae burrow into the rhino's stomach, where they attach and live through larval stages called "instars."
They emerge with the rhino's dung as larval "bots", then pupate and become adults. Then they have only a few days to find another rhinoceros host. This symbiotic relationship has no benefit to the rhino hosts, but the flies are "obligate parasites", which means they're dependent on the rhinos -- they can't complete their life cycle without them.
Oxpeckers Are Highly Visible Examples of Symbiotic Relationships
Oxpecker birds, also called tickbirds (Buphagus erythrorhynchus), specialize in riding on large African animals, including rhinos and zebras, feeding on external parasites like the bot fly larvae and ticks. The International Rhino Foundation describes how mynah birds serve the same role on rhinos in India. The oxpeckers feast on the parasites they find, and they also lend the favor of raising a loud warning when a predator approaches.
A Relationship Between Rhinos and Birds May Be Mutualistic or Parasitic
Researchers at the University of Zurich have studied the behavior of red-billed oxbirds among black rhinos in captivity at the Zoo Zürich, and they've found parasitic behavior among the birds. While the birds may hunt insects and ticks on their hosts, which is mutualistic behavior, they also peck at or create open wounds that can fester on their hosts. They might eat loose dead skin, or peck at existing wounds to promote bleeding. The rhinos would attempt to remove these birds by swishing their tails or shaking their legs. | <urn:uuid:6ecc0c8d-cdda-47aa-9530-1a6ac769e5ee> | 3.859375 | 689 | Knowledge Article | Science & Tech. | 35.858913 | 95,515,876 |
Now, collaboration between researchers at the Salk Institute for Biological Studies and Weill Cornell Medical College has revealed that brain cells processing visual information adjust their filtering properties to make the most sense of incoming information.
“We are best at discriminating the facial features that are typical of our neighbors, and if they happen to be parrots, we become very good at recognizing individual birds,” explains Tatyana Sharpee, Ph.D., an assistant professor in the Laboratory for Computational Biology and the lead author on the current study, which has been published in the August 5 online edition of the Journal of Computational Neuroscience.
Neurobiologists are on a perennial quest to understand how the brain codes and processes information. In the past, they had to rely on simplified objects on a computer screen or random stimuli to garner information on how the brain’s visual circuitry works. “Ultimately we are interested in what happens in a natural environment,” explains Sharpee, “but some questions require more control over the properties of visual stimuli than a picture of a natural scene would allow.”
Neurons in the primary visual cortex only respond when a stimulus appears within a window covering a small part of the visual field that the eye sees. This window is known as the neuron’s “receptive field.” Whenever a stimulus enters the neuron’s receptive field, the cell produces a volley of electrical spikes, known as “action potentials” that can be recorded.
But these neurons don’t react to just anything. Instead they are highly specialized and can only “see” a single attribute such as color, motion, or a specific luminance pattern. By measuring a certain neuron’s action potentials in response to random visual stimuli the researchers can infer the profile of its receptive field.
But growing evidence hints that this simple picture is incomplete. “The response of individual neurons can be strongly influenced by simple stimuli in the surround of the receptive field, a phenomenon known as contextual modulation,” explains Sharpee.
To unveil how contextual modulation shapes the apparent profile of neurons specialized in recognizing luminance patterns, Sharpee teamed up with Jonathan D. Victor, Ph.D., Fred Plum Professor of Neurology and Neuroscience at Weill Cornell Medical College in New York. The study made use of two sets of visual stimuli that were first introduced to neurophysiology by Victor. These stimuli matched in size, contrast, and luminance but differ in higher-order statistics leading to oriented checkerboard-like patterns in one case and pinwheel patterns in the other (see image). Single neurons’ responses to individual patterns were recorded in Victor’s laboratory.
Using complimentary methodologies developed by the two authors, who are leaders in applying information theory to extract meaning from a cacophony of signals, they then parsed the code for systematic, context-dependent changes in the neurons’ responses. Maybe not surprisingly, they found that larger receptive field components were more susceptible to contextual modulation and adjusted more than smaller ones.
But more importantly, they discovered that odd-symmetric components induced systematic changes across the whole population of neurons in the V1 area of the visual cortex, whereas even-symmetric components did not.
Odd-symmetric components are patterns that turn into their opposite when rotated by 180 degrees, such as a white and a black bar that are arranged parallel to each other. Even-symmetric components (such as a white bar sandwiched between two black bars) remain unchanged with this rotation.
“Context is an important part of how we perceive visual stimuli,” says Sharpee, “and these results show how individual neurons might adjust their properties in different natural environments, such as on a beach or in a forest.”
The research was supported by a grant from the Swartz Foundation and the National Institutes of Health.
The Salk Institute for Biological Studies in La Jolla, California, is an independent nonprofit organization dedicated to fundamental discoveries in the life sciences, the improvement of human health and the training of future generations of researchers. Jonas Salk, M.D., whose polio vaccine all but eradicated the crippling disease poliomyelitis in 1955, opened the Institute in 1965 with a gift of land from the City of San Diego and the financial support of the March of Dimes.
Gina Kirchweger | Newswise Science News
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When Francis Crick and James Watson discovered the double helical structure of deoxyribonucleic acid (DNA) in 1953, it began a genetic revolution to map, study, and sequence the building blocks of living organisms.
A rendering of the poly (rA)11 RNA double helical structure
DNA encodes the genetic material passed on from generation to generation. For the information encoded in the DNA to be made into the proteins and enzymes necessary for life, ribonucleic acid (RNA), single-stranded genetic material found in the ribosomes of cells, serve as intermediary. Although usually single-stranded, some RNA sequences were predicted to have the ability to form a double helix, much like DNA.
In 1961, Alexander Rich along with David Davies, Watson, and Crick, hypothesized that the RNA known as poly (rA) could form a parallel-stranded double helix based on the results of fibre diffraction experiments.
Fifty years later, scientists from McGill University successfully crystallized a short RNA sequence, poly (rA)11, and used data collected at the Canadian Light Source (CLS) and the Cornell High Energy Synchrotron to confirm the hypothesis of a poly (rA) double-helix.
The detailed 3D structure of poly (rA)11 was published by the laboratory of Dr. Kalle Gehring, McGill University, in collaboration with George Sheldrick, University of Göttingen, and Christopher WIlds, Concordia University. The paper appeared in the journal Angewandte Chemie International Edition under the title of “Structure of the Parallel Duplex of Poly (A) RNA: Evaluation of a 50 year-Old Prediction.”
“After 50 years of study, the identification of a novel nucleic acid structure is very rare. So when we came across the unusual crystals of poly (rA), we jumped on it,” said Dr. Gehring.
Gehring said identifying the double-helical RNA will have interesting applications for research in biological nanomaterials and supramolecular chemistry. Nucleic acids have astounding properties of self-recognition and their use as a building material opens new possibilities for the fabrication of bionanomachines – nanoscale devices created using synthetic biology.
“Bionanomachines are advantageous because of their extremely small size, low production cost, and the ease of modification,” said Gehring. “Many bionanomachines already affect our everyday lives as enzymes, sensors, biomaterials, and medical therapeutics.”
Dr. Gehring added that proof of the RNA double helix may have diverse downstream benefits for the medical treatments and cures for diseases like HIV and AIDS, or even to help regenerate biological tissues.
“Our discovery of the poly (rA) structure highlights the importance of basic research. We were looking for information about how cells turn mRNA into protein but we ended up answering a long-standing question from supramolecular chemistry.
For the experiments, Gehring and a team of researchers used data obtained at the CLS Canadian Macromolecular Crystallography Facility (CMCF) to successfully solve the structure of poly (rA)11 RNA.
CMCF Beamline Scientist Michel Fodje said the experiments were very successful in identifying the structure of the RNA and may have consequences for how genetic information is stored in cells.
“Although DNA and RNA both carry genetic information, there are quite a few differences between them,” said Dr. Fodje. “mRNA molecules have poly (rA) tails, which are chemically identical to the molecules in the crystal. The poly (rA) structure may be physiologically important, especially under conditions where there is a high local concentration of mRNA. This can happen where cells are stressed and mRNA becomes concentrated in granules within cells.”
With this information, researchers will continue to map the diverse structures of RNA and their roles in the design of novel bionanomachines and in cells during times of stress.
Reference: Safaee, N., Noronha, A. M., Rodionov, D., Kozlov, G., Wilds, C. J., Sheldrick, G. M., & Gehring, K. (2013). Structure of the Parallel Duplex of Poly (A) RNA: Evaluation of a 50 Year‐Old Prediction. Angewandte Chemie International Edition.
About the Canadian Light Source:
The Canadian Light Source is Canada’s national centre for synchrotron research and a global centre of excellence in synchrotron science and its applications. Located on the University of Saskatchewan campus in Saskatoon, the CLS has hosted 1,700 researchers from academic institutions, government, and industry from 10 provinces and territories; delivered over 26,000 experimental shifts; received over 6,600 user visits; and provided a scientific service critical in over 1,000 scientific publications, since beginning operations in 2005.
CLS operations are funded by Canada Foundation for Innovation, Natural Sciences and Engineering Research Council, Western Economic Diversification Canada, National Research Council of Canada, Canadian Institutes of Health Research, the Government of Saskatchewan and the University of Saskatchewan.
Synchrotrons work by accelerating electrons in a tube at nearly the speed of light using powerful magnets and radio frequency waves. By manipulating the electrons, scientists can select different forms of very bright light using a spectrum of X-ray, infrared, and ultraviolet light to conduct experiments.
Synchrotrons are used to probe the structure of matter and analyze a host of physical, chemical, geological and biological processes. Information obtained by scientists can be used to help design new drugs, examine the structure of surfaces in order to develop more effective motor oils, build more powerful computer chips, develop new materials for safer medical implants, and help clean-up mining wastes, to name a few applications.
Dr. Kalle Gehring | EurekAlert!
Further reports about: > Angewandte Chemie > Canadian Light Source > DNA > Evaluation > Poly > RNA > RNA molecule > RNA sequence > biological process > building block > double helix > genetic information > genetic material > living organism > medical implant > medical treatment > molecular chemistry > ribonucleic acid
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Sea-ice dynamics in an Arctic coastal polynya during the past 6500 years
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The production of high-salinity brines during sea-ice freezing in circum-arctic coastal polynyas is thought to be part of northern deep water formation as it supplies additional dense waters to the Atlantic meridional overturning circulation system. To better predict the effect of possible future summer ice-free conditions in the Arctic Ocean on global climate, it is important to improve our understanding of how climate change has affected sea-ice and brine formation, and thus finally dense water formation during the past. Here, we show temporal coherence between sea-ice conditions in a key Arctic polynya (Storfjorden, Svalbard) and patterns of deep water convection in the neighbouring Nordic Seas over the last 6500 years. A period of frequent sea-ice melting and freezing between 6.5 and 2.8 ka BP coincided with enhanced deep water renewal in the Nordic Seas. Near-permanent sea-ice cover and low brine rejection after 2.8 ka BP likely reduced the overflow of high-salinity shelf waters, concomitant with a gradual slow down of deep water convection in the Nordic Seas, which occurred along with a regional expansion in sea-ice and surface water freshening. The Storfjorden polynya sea-ice factory restarted at ~0.5 ka BP, coincident with renewed deep water penetration to the Arctic and climate amelioration over Svalbard. The identified synergy between Arctic polynya sea-ice conditions and deep water convection during the present interglacial is an indication of the potential consequences for ocean ventilation during states with permanent sea-ice cover or future Arctic ice-free conditions.
KeywordsArctic Storfjorden Polynya Holocene Sea ice
This work is a contribution to the CASE Initial Training Network funded by the European Community’s 7th Framework Programme FP7 2007/2013, Marie-Curie Actions, under Grant Agreement No. 238111. The research is part of the Centre for Arctic Gas Hydrate, Environment and Climate and was supported by the Research Council of Norway through its Centres of Excellence funding scheme Grant No. 223259. We thank the reviewers for their help improving the manuscript significantly.
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Mertensia ovum, also known as the Arctic comb jelly or sea nut, is a cydippid comb jelly or ctenophore first described as Beroe ovum by Johan Christian Fabricius in 1780. Unusually among ctenophores, which normally prefer warmer waters, it is found in the Arctic and adjacent polar seas, mostly in surface waters down to 50 metres (160 ft).
In addition to being weakly bioluminescent in blues and greens, comb jellies produce a rainbow effect similar to that seen on an oil slick, and which is caused by interference of incident light on the eight rows of moving cilia or comb rows which propel the organism. The comb rows beat sequentially, rather like the action of a Mexican wave. The comb rows also function as chemical sense organs, serving the same role as insect antennae. Mertensia ovum is the major source of bioluminescence from Arctic gelatinous zooplankton.
This species, like other ctenophores, has a large body cavity and is carnivorous, feeding on copepods and small crustaceans snagged by its two extremely sticky and robust tentacles (see Tentaculata). These are long and contractile with numerous lateral tentillae or side branches bearing colloblasts, each of which consists of a coiled spiral filament, structurally similar to a nematocyst, but instead of injecting a toxin, release an adhesive substance which ensnares the prey. These tentacles can be retracted into a tentacle sheath. The body is on the whole light pink in colour, oval in the tentacular plane and considerably compressed in the sagittal plane. Its unconventional brain consists of a network of nerves arranged under its outer skin.
A study in the Barents Sea found that it ingests prey ranging from small copepods to amphipods and krill, but that its staple diet consists of large copepod species such as Calanus finmarchicus, Calanus glacialis, Calanus hyperboreus and Metridia longa.
Like garden snails, Mertensia is hermaphroditic, reproducing sexually and occasionally asexually. Eggs and sperm are ejected into the water and from the fertilized eggs ovoid larvae develop. The planktonic larvae of this species are 2–3 millimetres (0.08–0.12 in) long while adults grow up to 10 centimetres (3.9 in).
The genus Mertensia commemorates the German naturalist Karl Heinrich Mertens aka Andrei Karlovich Mertens (17 May 1796 – 18 September 1830). Mertens accompanied the Russian naturalist Alexander Philipov Postels aboard the Senyavin in 1826 on a voyage to "reconnoitre and describe the coasts of Kamchatka, the land of the Chuchkis and the Koriaks (the coasts of which have not yet been described by anyone, and which are unknown except by the voyage of Captain Bering); the coasts of the Okhotsk Sea, and the Shantar Islands, which although they are known to us, have not been sufficiently described."
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- "LHSVirtualZoo - Mertensia Ovum". lhsvirtualzoo.wikispaces.com. Retrieved 12 December 2017. | <urn:uuid:15ccb1b0-8bfa-425b-826d-3e2a28090a58> | 3.71875 | 1,016 | Knowledge Article | Science & Tech. | 48.395334 | 95,515,952 |
Aspects of Using Multiprocessors for Meteorological Modelling
Since the introduction of computers for scientific research, meteorological modelling has always been one of the first disciplines to use the most advanced computers available at any given time. Today, meteorological institutions throughout the world operate class VI supercomputers like the CYBER 205, CRAY-1, or CRAY X-MP. Average processing speeds in excess of 200 Mflops (106 floating operations per second) are achievable for global weather prediction models with a horizontal resolution of about 100 km in grid-point space. As the results of the operational meteorological models are only useful during a very short time--the forecast for today is history tomorrow--the demands for greater processing power of computers are obvious, especially when one considers that a doubling in horizontal resolution extends the forecast range but in turn increases the computing requirements by the factor 8 = 2 3. The next logical step envisaged by meteorologists for the end of the decade is to double the model resolution without changing the elapsed time for the computation. Therefore, a computer capable of delivering around 1600 Mflops on average and in excess of 3000 Mflops as peak rate is required. This estimate of the computing speed assumes that the complexity of the calculations does not increase as well.
KeywordsGlobal Memory Shallow Water Model Tridiagonal System Vector Processor Sort Phase
Unable to display preview. Download preview PDF. | <urn:uuid:7421af01-2dfa-4b0e-a7b1-2fddd26d1c2c> | 2.875 | 288 | Truncated | Science & Tech. | 17.53031 | 95,515,973 |
Update: “Two environmental groups have announced plans to file suit to prevent BP from burning alive endangered sea turtles in the cleanup of the Gulf Coast,” Democracy Now! reports.
“The Center for Biological Diversity and Turtle Island Restoration Network say they’ll file suit against BP as well as the US Coast Guard under the Endangered Species Act,” the daily public news show adds.
A RAW STORY article on sea turtles being burned alive has gone viral over the Internet, receiving over 16,000 Facebook links.
Original AP story follows
An effort to save thousands of sea turtle hatchlings from dying in the oily Gulf of Mexico will begin in the coming weeks in a desperate attempt to keep an entire generation of threatened species from vanishing.
The U.S. Fish and Wildlife Service will coordinate the plan, which calls for collecting about 70,000 turtle eggs in up to 800 nests buried in the sand across Florida Panhandle and Alabama beaches.
It’s never been done on such a massive scale. But doing nothing, experts say, could lead to unprecedented deaths. There are fears the turtles would be coated in oil and poisoned by crude-soaked food.
“This is an extraordinary effort under extraordinary conditions, but if we can save some of the hatchlings, it will be worth it as opposed to losing all of them,” said Chuck Underwood of the U.S. Fish and Wildlife Service.
“We have a much higher degree of certainty that if we do nothing and we allow these turtles to emerge and go into the Gulf and into the oil … that we could in fact lose most of them, if not all of them,” he added. “There’s a chance of losing a whole generation.”
Dozens of workers are fanned out across the coast marking turtle nests, most of them threatened loggerheads, which nest largely along Florida Panhandle and Alabama beaches.
In about 10 days, they will begin the arduous process of excavating the nests, mostly by hand. The digging must be slow and delicate  aside from making sure the shells don’t crack, the eggs can’t be rolled around or repositioned to protect the embryo inside.
Then the eggs will be carefully placed in specially designed Styrofoam containers, like coolers, along with sand and moisture to mimic the natural nest. The containers will then be trucked about 500 miles east to a temperature-controlled warehouse at Florida’s Kennedy Space Center.
There, the eggs will remain until hatchlings emerge, and they will be placed one-by-one on Florida’s east coast, where the turtles can swim oil-free into the Atlantic Ocean.
“There’s a whole lot of unknowns in what we’re doing,” Underwood acknowledged, noting many of the hatchlings could die anyway because of the stressful moving process.
All of the sea turtles that venture into Gulf waters have already suffered because of commercial fishing and habitat loss. Endangered Kemp’s ridleys, which are nesting on beaches in Mexico and Texas, have washed up by the dozens dead along Gulf beaches since the April 20 Deepwater Horizon rig explosion that has gushed up to 130 million gallons of oil into the sea.
While some have been found oiled, it remains unclear how many of them died because of it. Tests are ongoing. The Kemp’s ridleys aren’t in as immediate of danger because oil hasn’t been washing ashore yet in their nesting places in the western Gulf. But some fear those hatchlings also could eventually make it into the crude.
Threatened loggerheads, which are currently being considered for the added protection of endangered status, also have been found oiled and dead since the spill started, along with leatherbacks and green turtles.
David Godfrey, executive director of the Gainesville, Fla.-based Sea Turtle Conservancy, agrees this plan is the only option to save as many turtles as possible.
He said if left alone, the turtles will soon begin emerging from their nests and heading straight out to sea to feed in masses of oil-soaked seaweed.
Even more unusual, in a field that typically sees division between government entities and conservationists, there is agreement on what to do. Teri Shore, program director with the California-based Sea Turtle Restoration Project, said she thought the plan was good given the circumstances.
“If those sea turtles swim out to the Gulf, they’re going to face a massive oil slick which will cause them to perish or at least significantly decrease their chances of survival,” she said.
Godfrey said he agreed with the strategy and called it a “pretty amazing plan” because conservationists rarely support relocating sea turtle nests. They often push for a change in human behaviors, such as dimming lights along beaches at night to avoid disorienting them.
But no one can control the oil, he noted.
“We’re talking about allowing the entire year’s class of hatchlings to emerge and swim to their certain doom, and are we just going to sit back and let that happen?” he said. “We just can’t.” | <urn:uuid:6420ec91-4a70-456e-bea0-0a11673f0265> | 2.859375 | 1,108 | News Article | Science & Tech. | 51.039356 | 95,515,977 |
Chlorine dioxide is a neutral chlorine compound with the formula ClO2. Although similar in name to chlorine, chlorine dioxide is very different from elemental chlorine, both in its chemical structure and in its behavior (think carbon v. carbon dioxide). One of the most important qualities of chlorine dioxide is its high solubility in water, especially in cold water. Chlorine dioxide does not hydrolyze (or undergo a chemical breakdown reaction) when it enters water. Instead, chlorine dioxide remains intact as a dissolved gas in water. In comparison, chlorine dioxide is approximately 10 times more soluble in water than chlorine.
The molecule ClO2 has an odd number of valence electrons, and therefore, it is a paramagnetic radical. Its electronic structure has long baffled chemists because none of the possible Lewis structures is very satisfactory. In 1933, L. O. Brockway proposed a structure that involved a three-electron bond. Chemist Linus Pauling further developed this idea and arrived at two resonance structures involving a double bond on one side and a single bond plus three-electron bond on the other. In Pauling’s view the latter combination should represent a bond that is slightly weaker than the double bond. In molecular orbital theory this idea is commonplace if the third electron is placed in an anti-bonding orbital. Later work has confirmed that the highest occupied molecular orbital is indeed an incompletely-filled antibonding orbital.
Acidification of Chlorite
5 ClO2 + 4H+ → 4 ClO2 + 2 H2O + Cl-
Oxidation of Chlorite by Chlorine
2 NaClO2 + Cl2 → 2 NaCl + ClO2
Oxidation of Chlorite by Persulfate
2 NaClO2 + Na2Cl2O8 → 2 ClO2 + 2 Na2SO4
Action of Acetic Anhydride on Chlorite
2 NaClO2 + (CH3CO)2O + H2O → ClO2 + NaCl + CH3COOH + CH3COONa + H2
Reduction of Chlorates by Acidification in the Presences of Oxalic Acid
2 HClO3 + H2C2O4 + H2O → 2 ClO2 + 2 CO2 + 2 H2O
Reduction of Chlorates by Sulfurous Anhydride
2 NaClO3 + H2SO4 + SO2 → 2 ClO2 + 2 CO2 + 2 NaHSO4
ClO2 is a very small molecule, e.g., it can penetrate into very small areas. As a gas Cl02 will completely and evenly fill any space, giving it unmatched distribution and diffusion.
Cl02 is much smaller than other particles and molecules. Because of its size, Cl02 is a stronger oxidizer and works at much lower concentrations. Because ClO2 works at much lower concentrations, it is also less corrosive.
As a true gas, Cl02 is able to contact organisms wherever they are located and penetrate into tight, hidden or difficult to reach areas, including microscopic cracks and crevices.
OSHA regulates the level of chlorine dioxide in the workplace air. The occupational exposure limit for an 8-hour workday, 40-hour workweek is .1 parts per million (.1 ppm) or .28 milligrams per cubic meter (mg/m3) | <urn:uuid:6bbc85cd-e8af-4fd2-a488-dff96f14b467> | 4 | 712 | Knowledge Article | Science & Tech. | 41.675297 | 95,515,995 |
Lecturer, University of Lagos, Nigeria
Is about microalgae which are primary producer and carbondioxide utilizer.
This micro plants can manufacturing its own food (photosynthesis)in which other organisms depend on hence they are called autotrophs . They are very relevant in all aspect of life because without these organisms manufacturing food, other food that human beings depend on may not be readily available whether on land or aquatic environment. these organisms have many potentials in medicine, agriculture, pharmacy, environment and many more. They are green patches that we see on the bricks or on our houses at times. They can be found anywhere that is moist. they are very valuable in all aspect of live as these organisms are been used for biodiesel because of their lipids content as well. The diatoms, are made up of silica (form of glass) because of this, they are also utilized for fossil records (that is to show what happened years back in an environment). These organisms are rich in Vitamins, Proteins and some have been synthesized for their various usage especially in the area of food supplements. Some of these organisms could be macroscopic e,g Porphyra, which are commonly called Seaweed and serve as food especially in Asia (Japan) | <urn:uuid:05c689f1-033b-480d-9d00-8008cd728b38> | 2.671875 | 263 | Nonfiction Writing | Science & Tech. | 26.723166 | 95,516,025 |
Don't bet the future of the climate on negative emissions technology, Stanford University scientists say.
Some of the world’s most vulnerable live in the tropics, where sea rise will cause a sharp rises in floods.
Temperatures were high in the Arctic and well above average in the Eastern U.S., China and Africa.
Northern tundra’s autumn carbon dioxide emissions increased 70 percent between 1975 and 2015.
Rising temperatures are causing less of each winter’s snowpack to flow down a major river as water.
Unscientific climate policy buried in a bipartisan spending deal could persist through future administrations.
A federal budget deal for the rest of 2017 leaves most climate and science programs intact.
America's first offshore wind farm just shuttered a diesel electric power plant in Rhode Island.
Over Trump's first 100 days, we're going to show what science tells us about our warming world.
Environmental regulations played a small role in the coal industry's decline, a Columbia University report says.
The Trump administration will recommend to Congress ways it can shrink or abolish national monuments.
A new study shows air pollution from Canada's oil sands could be 4 times higher than previously reported.
As rich countries have foundered, India and China have emerged as global leaders in tackling warming.
References to greenhouse gases and reducing petroleum have been deleted in favor of the economy.
Removing carbon dioxide from the air may be the most effective way to meet the globe's ambitious climate goals.
Climate change has the planet on a hot streak it's unlikely to break anytime soon.
Harvard scientists plan to undertake one of the first outdoor geoengineering experiments next year.
Communities across the West will have to adapt to living with the ever-increasing threat of wildfires.
The march is not about politics. It is about not throwing away our great engine of truth.
March was the second hottest March on record, according to NASA, behind only 2016, a mark of rising global warming. | <urn:uuid:232528ec-7bb6-41b6-b4d8-c777be4d18de> | 2.90625 | 409 | Content Listing | Science & Tech. | 48.749682 | 95,516,030 |
Riverscapes and Mindscapes Using Inventory, Monitoring, and Biogeography to Explore Riparian Man
The western United States is among the most geographically diverse regions in the world. This heterogeneous landscape has fascinated biogeographers and explorers for centuries, yet poses daunting challenges for environmental managers in search of generalizable frameworks for understanding riparian plant composition, diversity, and resilience. Numerous studies of the last two decades have demonstrated that riparian ecosystems are governed by a complex array of factors that can be viewed hierarchically from large scale biogeographic patterns through less coarse watershed-scale gradients to local scale drivers of hydrology, geomorphology, and biotic and abiotic disturbance. Increasingly, humans influence all levels of the hierarchy. Environmental managers often accumulate management paradigms from institutional knowledge and histories, on-the-job experience and other diverse sources. Consequently, “management domains” presently used in riparian ecosystems may be ad hoc accumulations of knowledge that align haphazardly with biogeographic or other environmental boundaries. Here we discuss the concept of riparian management domains to prompt discussion of how to better align ecological and management boundaries. We will review recent research that compares within-site and among-site patterns in riparian biodiversity. Much of this research has helped to distinguish which elements of riparian ecosystems show a strong biogeographic structure from those that tend to be governed primarily by local environmental and biotic effects. We will also review first principles of riparian biogeography and highlight the value of place-based inventory and monitoring to inform place-based riparian management and restoration and to advance human understanding of riparian ecosystems across the American West. | <urn:uuid:fbdde0ca-f021-4ce5-9902-da50ec826097> | 2.875 | 339 | Academic Writing | Science & Tech. | -6.429842 | 95,516,045 |
Saturday science subject: ITER agreement signed
A consortium of nations including China, the European Union, India, Japan, Korea, Russia, and the United States has signed an agreement
that officially authorizes the construction of the ITER
nuclear fusion reactor. The project will go ahead in Cadarache, France, where ITER expects to start clearing land to make way for construction in the spring of 2007. According to the BBC, the facility will begin to take shape in 2009, and it could begin to output electricity to the grid within 30 years. Construction will cost €5 billion ($6.54 billion), half of which will be shouldered by the European Union.
Even though critics argue that the money could be better spent on proven energy sources, the project could eventually guarantee virtually limitless energy with much greater yields than solar or wind power. Fusion power doesn't share the downsides of fission power, either, as the amount of radioactive waste produced is significantly smaller and has a short half-life (just 12.5 years, compared to around 24,000 years for plutonium-239.) That said, ITER's Jerome Pamela told the BBC that it may take up to a century for fusion power to become the dominant source of electricity on Earth. | <urn:uuid:8f73d295-e559-4d95-bd2a-57e7570b7887> | 3.046875 | 254 | News Article | Science & Tech. | 45.902222 | 95,516,054 |
Plants require four simple things to live: water, warm temperature, light, and minerals. Most places that consist partly of these vital requirements will be hospitable environments for plants, but some have adapted to survive in extreme conditions. What can we learn from these adaptations, and can we utilize them in space exploration? How might these plants reveal what extraterrestrial life might look like? Join Jennifer McElwain, Head of the Botany Department at Trinity College Dublin, to find out more.
Jennifer McElwain holds the 1711 Chair of Botany at Trinity College Dublin's School of Natural Sciences. She is currently the Head of Botany within the School. Over the past 20 years her research and teaching have focused on the development and use of palaeobotanical methods (proxies) that use fossil plants to reconstruct the evolution of Earth's atmospheric composition and climate on multimillion year timescales. Her research team use both fossil plants and modern experimentation to investigate how fluctuations in atmospheric composition and climate have influenced plant evolution and ecology throughout Earth history. | <urn:uuid:393f0dc2-0b0b-4db3-944e-b66e5aea02fd> | 3.734375 | 215 | News (Org.) | Science & Tech. | 27.415774 | 95,516,067 |
Warming climate could speed forest regrowth in eastern US
Warming climate could speed the natural regrowth of forests on undeveloped or abandoned land in the eastern United States, according to a new study. Previous research has shown that the succession from field to forest can happen decades sooner in the southeastern US than in the Northeast. But it wasn’t obvious why. A new study points to temperature as the major factor influencing the pace of reforestation.
Go to Source | <urn:uuid:7c899b82-edf1-43fa-bbfd-d9dfc2148572> | 2.859375 | 96 | Truncated | Science & Tech. | 44.83 | 95,516,084 |
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Volunteer beetle-ranchers raising army of bugs to fight purple loosestrife invasion
STEVENS POINT – A group of volunteers scattered across central Wisconsin has taken up a new hobby and is raising an army of defenders tasked with fighting off an invasion.
They are beetle ranchers, raising tens of thousands of tiny galerucella pusilla bugs that will be turned loose in the wild where they and their insatiable appetites will mow down waves of the invasive species of plants called purple loosestrife.
Their ranches have no stables or barns. Instead, Karen Dostal and other volunteers have in their yards plants draped in netting and sitting in wading pools filled with vile-looking murky water. That is the preferred environment of purple loosestrife, a plant from Europe that plagues Wisconsin wetlands, where it grows out of control and makes it nearly impossible for native plant life to grow.
The defense until recently primarily has involved treating wetlands with gallons and gallons of herbicide. But now, armies of beetles are being raised to beat back the European invasion, said Kaycie Stushek, the regional aquatic invasive species specialist for the Golden Sands Resource Conservation and Development Council Inc.
“All this project is really doing is introducing a native predator,” Stushek said. “They are not going to move on to other plants.”
To raise the army, Dostal, the environmental education coordinator at Boston School Forest, built the wading-pool ranch and planted five net-covered loosestrife stalks upon which her herd of beetles — it started as just five or six bugs on each plant — is feeding.
“Over time they reproduce, and eventually you’ll have thousands of beetles in each one of those nets, and then the beetles are released along the Wisconsin River and other wetland areas where there’s a lot of purple loosestrife, and they will eat it up,” Dostal said.
Purple loosestrife is an unusual invasive. It’s actually quite an attractive flowering plant that also has some medicinal properties. But it can also wipe out native plants in short order.
Stushek said the beetles, which look a bit like tan lightning bugs, weaken the plants and make it difficult for them to flower and go to seed. At this time of year, the beetles are mating and herds are expanding, Stushek said — a happy coincidence during June, which is designated as Wisconsin’s Invasive Species Awareness Month.
“The beetles lay their eggs on the plants,” Stushek said. “When the larvae hatch, they eat the foliage on the plants, then drop down into soil and come out as adults. When they emerge, the plants should be all eaten up.”
The plants are such a problem that the state has one guy, Brock Woods, in charge of controlling them. Woods is the purple loosestrife and wetland invasive plant coordinator for the Department of Natural Resources, and he said the bugs have been working everywhere they’ve been released.
“This is cost-effective and environmentally safe,” Woods said. “It has been one of the most effective biological control projects we’ve ever seen when you consider how little herbicide is used on that plant.”
Stushek said all of the roots and beetles provided to the volunteer ranchers were collected by volunteers and employees of Golden Sands. Amy Thorstenson, executive director of the Golden Sands office downtown and regional aquatic invasive species coordinator for Portage and surrounding counties, said the aim of the project is not to eradicate purple loosestrife, but to weaken the plants and prevent them from spreading. Once the beetles are released, Thorstenson said, they will move about and attack any new invaders they find.
“After they mature and have eaten most of the loosestrife plant, they fly off in search of more,” Thorstenson said. “It’s like free labor from the beetles. I love it.”
The project is supported by the DNR and more than 10 collaborators, including the Wisconsin River Academy, University of Wisconsin-Stevens Point biology students, the Waupaca Natural Resources Foundation, Waupaca County Master Gardeners, and the Waupaca County Land and Water Conservation Department.
Andy Davis can be reached at 715-345-2253. Find him on Twitter as @SPJAndyDavis.
How to get involved
Call the Golden Sands Resource Conservation and Development Council Inc. at 715-343-6215. | <urn:uuid:2428dc42-fa19-4748-9ec6-8c33d67b951b> | 2.78125 | 998 | News Article | Science & Tech. | 40.951169 | 95,516,111 |
The mean magnetic field of the Sun: Observations at Stanford
A solar telescope has been built at Stanford University to study the organization and evolution of large-scale solar magnetic fields and velocities. The observations are made using a Babcock-type magnetograph which is connected to a 22.9 m vertical Littrow spectrograph. Sun-as-a-star integrated light measurements of the mean solar magnetic field have been made daily since May 1975. The typical mean field magnitude has been about 0.15 G with typical measurement error less than 0.05 G. The mean field polarity pattern is essentially identical to the interplanetary magnetic field sector structure (see near the Earth with a 4 day lag). The differences in the observed structures can be understood in terms of a ‘warped current sheet’ model.
KeywordsMagnetic Field Current Sheet Interplanetary Magnetic Field Field Polarity Typical Measurement
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During large storms, barrier islands are temporarily underwater because of storm surge and high waves. This is called overwash, and during overwash sand is moved from the beach and deposited in back-barrier environments. The sandy deposit that forms as a result of overwash is called a washover. Below is an animation that shows the evolution of a washover (Site 2) on Onslow Beach, NC during a 4-year period. Some of the most dramatic morphologic changes occurred after Hurricane Sandy and during a persistent nor’easter in October, 2015. We are still working with these data, so stay tuned.
3431 Arendell St.
Morehead City, NC
Lesson plans for middle- and high-school teachers that focus on estuarine fish habitats can be found here.
Lab Musings (mostly)
- I always suspected birthday cake could be used as a garnish. #confirmed https://t.co/kNS7tkibCS 08:06:46 PM July 05, 2018 from Twitter for iPhone ReplyRetweetFavorite
- Catching up on some data processing this morning and look what I found. Some jokers throwing down the @UNC sign.… https://t.co/yL4vq0myCp 12:56:59 PM June 29, 2018 from Twitter for iPhone ReplyRetweetFavorite
- Great field trip to Back Sound & Shackleford Banks with the boss of my boss’s boss @ChancellorFolt Looking forward… https://t.co/Npgc1jtLqn 01:08:49 AM June 27, 2018 from Twitter for iPhone ReplyRetweetFavorite
Molly Bost wins
Second place best poster award at UNC 5th annual Climate Change and Resilience Symposium. April 20, 2018.
Congratulations! Charlie and Anna graduate with MS degrees. | <urn:uuid:0b0b87b2-3162-451b-9790-de80fe3a24e7> | 2.84375 | 387 | News (Org.) | Science & Tech. | 60.94923 | 95,516,172 |
Lignin is a complex polyphenyl aromatic compound which exists in tight associations with cellulose and hemicellulose to form plant primary and secondary cell wall. Lignocellulose is an abundant renewable biomaterial present on the earth. It has gained much attention in the scientific community in recent years because of its potential applications in bio-based industries. Microbial degradation of lignocellulose polymers was well studied in wood decaying fungi. Based on the plant materials they degrade these fungi were classified as white rot, brown rot and soft rot. However, some groups of bacteria belonging to the actinomycetes, α-proteobacteria and β-proteobacteria were also found to be efficient in degrading lignocellulosic biomass but not well understood unlike the fungi. In this review we focus on recent advancements deployed for finding and understanding the lignocellulose degradation by microorganisms. Conventional molecular methods like sequencing 16s rRNA and Inter Transcribed Spacer (ITS) regions were used for identification and classification of microbes. Recent progression in genomics mainly next generation sequencing technologies made the whole genome sequencing of microbes possible in a great ease. The whole genome sequence studies reveals high quality information about genes and canonical pathways involved in the lignin and other cell wall components degradation.
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|MLA Citation:||Bloomfield, Louis A. "Question 1116"|
How Everything Works 17 Jul 2018. 17 Jul 2018 <http://howeverythingworks.org/print1.php?QNum=1116>.
X-ray crystallography is an important tool for materials science and molecular biology. Just as the colored interference patterns that appear on a soap bubble when sunlight reflects from that bubble tell you something about the structure of that soap bubble, so the X-rays that reflect from a crystal tell you something about the structure of that crystal. X-rays experience interference after they reflect from a crystal and the interference patterns can tell you where individual atoms are located within a crystal or within the molecules from which the crystal is made. Materials scientists use this information to understand the crystals they have produced while molecular biologists use it to understand the molecular structures of complicated biological molecules. | <urn:uuid:7c9656fa-a072-4202-ba8e-b31f4e38be3e> | 3.65625 | 179 | Knowledge Article | Science & Tech. | 43.826794 | 95,516,187 |
Most in-lake restoration projects use deeply intrusive methods. They include the removal of bottom sediments and the use of high doses of precipitants. They are very radical, causing extinction of many organisms, and are very expensive. Alternative methods described in this paper are inexpensive, easy to use, effective, and sustainable (energy-efficient, not destructive for most of the biota). They have been applied to three lakes located in Poznań and the surrounding area (Western Poland) and their effectiveness has been documented. They include: (i) use of biomanipulation to increase trophic influence of zooplankton on phytoplankton, and small doses of iron sulphate to reduce phosphorus content in the water column, used in Maltań ski Reservoir, (ii) delivering water rich in nitrates from small tributaries to the deepest part of the lake, thus increasing redox potential and limiting the release of phosphorus from bottom sediments, used in Uzarzewskie Lake, (iii) oxygenation of hypolimnetic waters using wind aerators, iron treatment with small doses of coagulant and biomanipulation, used in Durowskie Lake. Use of limited doses of an innovative solid phosphorus precipitant called Sinobent1 is also possible. These methods, in accordance with the intermediate disturbance hypothesis, increased the diversity of flora and fauna in the lakes and contributed to improvements in water quality. Simultaneous application of several methods, which prevented feedback mechanisms, increased the efficiency of lake restoration. © 2014 European Regional Centre for Ecohydrology of Polish Academy of Sciences.
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Scientists using NASA’s Swift satellite and several ground-based telescopes have detected the most distant explosion yet, a gamma-ray burst from the edge of the visible universe.
This powerful burst was detected September 4. It marks the death of a massive star and the birth of a black hole. It comes from an era soon after stars and galaxies first formed, about 500 million to 1 billion years after the Big Bang.
“We designed Swift to look for faint bursts coming from the edge of the Universe,” said Swift principal investigator Dr. Neil Gehrels of NASA Goddard Space Flight Center in Greenbelt, Md. “Now we’ve got one and it’s fascinating. For the first time we can learn about individual stars from near the beginning of time. There are surely many more out there,” he added.
Only one quasar has been discovered at a greater distance. Quasars are super-massive black holes containing the mass of billions of stars. This burst comes from a lone star. Scientists say it is puzzling how a single star could have generated so much energy as to be seen across the entire Universe. The science team has not yet determined the nature of the exploded star. A detailed analysis is forthcoming.
Scientists measure cosmic distances via redshift, the extent to which light is “shifted” toward the red, or lower energy, part of the electromagnetic spectrum during the light’s long journey across the Universe. The greater the distance, the higher the redshift.
The September 4 burst, named GRB 050904, has a redshift of 6.29, which translates to a distance of about 13 billion light-years from Earth. The Universe is thought to be 13.7 billion years old. The previous most distant gamma-ray burst had a redshift of 4.5. The most distant quasar known is at a redshift of 6.4.
This burst was also very long, lasting more than 200 seconds, whereas most bursts last only about 10 seconds. The detection of this burst confirms that massive stars mingled with the oldest quasars. The detection also confirms that even more distant star explosions can be studied through combined observations of Swift and the network of world-class telescopes.
“This is uncharted territory,” said Dr. Daniel Reichart, University of North Carolina (UNC), Chapel Hill, who spearheaded the distance measurement. “This burst smashes the old distance record by 500 million light-years. We are finally starting to see the remnants of some of the oldest objects in the Universe,” he added.
Swift detected the burst and relayed its coordinates within minutes to scientists around the world. Reichart’s team discovered the afterglow using the Southern Observatory for Astrophysical Research (SOAR) telescope atop Cerro Pachon, Chile. Over the next several nights, the UNC team used SOAR and the Gemini South telescope, also on Cerro Pachon, to calculate a redshift of greater than 6 using a light filtering technique. A team led by Nobuyuki Kawai of the Tokyo Institute of Technology used the Subaru Observatory on Mauna Kea, Hawaii, to confirm the distance and fine-tune the redshift measurement to 6.29, using a technique called spectroscopy.
“The earliest stars exploded eons ago, we know very little about them,” said Josh Haislip, a UNC team member who analyzed data from SOAR. “One of the best ways we can study them is by watching for their explosions. Swift can pinpoint the location of the explosions, and telescopes such as SOAR can study the composition of the debris to understand where and when these stars formed and what they were made of,” he added.
The SOAR telescope is funded by the U.S. National Optical Astronomy Observatory, Tucson, Ariz., through the National Science Foundation (NSF), Arlington, Va.; the Ministry of Science of Brazil; Michigan State University, East Lansing; and UNC. The twin Gemini Observatory telescopes represent an international partnership funded in part by the NSF. Goddard manages the Swift mission for NASA’s Science Mission Directorate, Washington. Mission operations are conducted by Penn State University, University Park. Swift’s other national laboratories, universities and international partners include the Los Alamos National Laboratory, N.M.; Sonoma State University, Rohnert Park, Calif.; the United Kingdom; and Italy.
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Scientists and engineers from the Woods Hole Oceanographic Institution (WHOI) have just completed a successful test of new robotic vehicles designed for use beneath the ice of the Arctic Ocean. The multidisciplinary research team will now use those vehicles to conduct the first search for life on the seafloor of the world’s most isolated ocean.
WHOI researchers have built two new autonomous underwater vehicles (AUVs) and a new tethered, remote controlled sampling system specifically for the difficult challenges of operations in the Arctic ice. They hope to discover exotic seafloor life and submarine hot springs in a region of the ocean that has been mostly cut off from other ecosystems for at least 26 million years.
The 30-member research team will depart on July 1 from Longyearbyen, Svalbard, for a rare expedition to study the Gakkel Ridge, the extension of the mid-ocean ridge system which separates the North American tectonic plate from the Eurasian plate beneath the Arctic Ocean.
The 40-day cruise on the Oden—a 108-meter long (354-foot) icebreaker operated by the Swedish Maritime Administration—will take researchers close to the geographic North Pole.
The research team for the Arctic Gakkel Vents Expedition (AGAVE) includes specialists in each field of deep-sea exploration, with scientists and engineers from the United States, Norway, Germany, Japan, and Sweden.
WHOI geophysicist Robert Reves-Sohn will serve as chief scientist. Fellow principal investigators include: Tim Shank, a hydrothermal vent biologist from WHOI; Hanumant Singh, a WHOI engineer and vehicle developer; marine chemist Henrietta Edmonds of the University of Texas at Austin, who sailed on the last research expedition to the Gakkel Ridge in 2001; Susan Humphris, a WHOI geochemist who has surveyed dozens of hydrothermal vent sites around the world; and Peter Winsor, a WHOI oceanographer who studies Arctic Ocean circulation and its implications for climate.
Major funding for the expedition and for vehicle development was provided by the National Science Foundation (NSF) and the National Aeronautics and Space Administration (NASA).
“This is an exciting opportunity to explore and study a portion of Earth’s surface that has been largely inaccessible to science,” said Reves-Sohn. “Any biological habitats at hydrothermal vent fields along the Gakkel Ridge have likely evolved in isolation for tens of millions of years. We may have the opportunity to lay eyes on completely new life forms that have been living in the abyss beneath the Arctic ice pack.”
Most of the instrumentation that researchers would normally use to study deep sea environments and organisms—such as the human occupied submersible Alvin or tethered vehicles—cannot be safely operated in the Arctic ice, which can easily crush most small vehicles. So researchers asked Singh and colleagues to design and develop three new vehicles from scratch.
During the July expedition, researchers will use the Puma AUV, or “plume mapper,” to sniff out the chemical and temperature signals of hot, mineral-rich fluids venting out of the ocean floor. Once Puma finds the source of venting, Singh and colleagues will send down the Jaguar AUV, which will use cameras and bottom-mapping sonar systems to image the seafloor. Finally, the CAMPER towed vehicle will be lowered to the seafloor to scoop or vacuum up rocks, sediments, and living creatures.
During a 10-day engineering trial in May and June 2007, all three vehicles were lowered through the Arctic ice and driven underwater, while engineers simultaneously tested acoustic communications techniques. The researchers were able to recover their vehicles from beneath the ice, which can be risky in the midst of moving floes that can quickly close the leads around an icebreaker.
“Anyone can deploy an AUV in the Arctic; the trick is getting it back,” said Singh, who will send his vehicles to the seafloor for 10 to 24 hours at a time during the Gakkel expedition. “In order to have a good day with autonomous vehicles, the number of recoveries must equal the number of launches.”
The Gakkel Ridge extends roughly 1,800 kilometers (1,100 miles) from north of Greenland toward Siberia. It is both the deepest ocean ridge—ranging from 3 to 5 kilometers (1.8 to 3 miles) beneath the ice cap—and the slowest spreading tectonic plate boundary anywhere on Earth. The ridge moves roughly one centimeter (1/3 inch) per year, about 20 times slower than most other ridges.
At most mid-ocean ridges, Earth’s crust spreads apart, allowing hot magma from the mantle to come up and form new ocean crust. The enormous heat sparks chemical reactions between crustal rocks and the seawater that seeps down into them.
These chemical reactions produce hot, mineral-rich fluids that spew like geysers from seafloor vents, as well as massive deposits of minerals, such as copper and zinc. These hydrothermal fluids also contain chemicals that sustain rich communities of unusual life forms, which thrive via chemosynthesis, rather than photosynthesis.
Many geologists believed the Gakkel Ridge region would be too geologically cold to produce hydrothermal vents. And yet during a 2001 expedition, researchers found signs of such venting in the Arctic. Where there are vents, there may be unusual seafloor life forms.
“A few years ago, mid-ocean ridge and hydrothermal vent biologists came together and asked: ‘Where are the key places in the world to go to make big leaps in understanding biodiversity?’ The Gakkel Ridge was one of the top places,” said Shank, who plans to study the genetics of animals found during the expedition.
“The region has been mostly separated from the Atlantic and Pacific oceans for millions of years, so whatever lives there has since been evolving in relative isolation—much the way animals in Australia did," Shank added. "We know that deep-sea Arctic fauna found away from vents are more than 70 percent different from all others around the world. So at hydrothermal vents we are likely to find completely new suites of species with never-before seen adaptations.”
Some scientists—including program managers and scientists from the NASA Astrobiology Program—have been keenly interested in the possibility that Gakkel Ridge may harbor life forms and environmental conditions consistent with primordial Earth or other watery planets.
“The origin of life discussion comes up because the rocks that are exposed on this very slow spreading ridge are not volcanic, but instead come directly from Earth’s mantle,” said Humphris. “The chemistry is very much like the volcanism that occurred on the primordial Earth. If you are thinking about origins of life, you’d like to have an area that is the closest analog to what was happening on the early Earth.”
In July 2001, WHOI researchers were part of the Arctic Mid-Ocean Ridge Expedition (AMORE) that produced the first detailed maps of the Gakkel Ridge and made the unexpected discovery that the ridge is volcanically active. Scientists also found that large sections of Earth’s mantle appear to be deposited directly onto the seafloor along the Gakkel Ridge.
The Gakkel Ridge expedition will be covered live on the web, allowing students, educators, and the general public to follow along with daily dispatches from the Arctic Ocean. The Dive and Discover web site brings students and teachers along on research field trips to read about science in action, while the Polar Discovery project uses photos and live phone calls from the Oden to allow museum visitors and the public to see the Arctic through the eyes of the explorers.
Support for the Gakkel Ridge expedition and for underwater vehicle development has been provided by the National Science Foundation’s Office of Polar Programs and Division of Ocean Sciences; the NASA Astrobiology Program; the WHOI Deep Ocean Exploration Institute; and the Gordon Center for Subsurface Sensing and Imaging Systems, an NSF Engineering Research Center.
The Woods Hole Oceanographic Institution is a private, independent organization in Falmouth, Mass., dedicated to marine research, engineering, and higher education. Established in 1930 on a recommendation from the National Academy of Sciences, its primary mission is to understand the oceans and their interaction with the Earth as a whole, and to communicate a basic understanding of the ocean's role in the changing global environment.
Media Relations Office | EurekAlert!
Upcycling of PET Bottles: New Ideas for Resource Cycles in Germany
25.06.2018 | Fraunhofer-Institut für Betriebsfestigkeit und Systemzuverlässigkeit LBF
Dry landscapes can increase disease transmission
20.06.2018 | Forschungsverbund Berlin e.V.
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
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Do you know what a meteor is, or what scientists mean when they are talking about cryogenics? Our collection of science terms explains the meaning of some of the most common scientific ideas.
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What in the World Is Dog Trancing? | <urn:uuid:ef35d935-fa66-4c90-942d-f339236fd5b0> | 3.484375 | 426 | Content Listing | Science & Tech. | 59.5936 | 95,516,216 |
But Livermore scientists and international collaborators have developed a new tool that will help scientists better represent the clouds observed in the sky in climate models.
Traditionally, observations from satellites infer the properties of clouds from the radiation field (reflection of sunlight back into space, or thermal emission of the planet). However, to accurately utilize satellite data in climate model assessment, a tool is required that allows an apples-to-apples comparison between the clouds simulated in a climate model and the cloud properties retrieved from satellites.
"The models are becoming more interactive and are taking into account the radiation data from the satellite observations and is an important part of the process of making better climate models," said the Lab's Stephen Klein, who along with LLNL's Yuying Zhang and other collaborators have developed the Cloud-Feedback-Model Intercomparison Project Observation Simulator Package (COSP).
"The models have been improving and refining their representations of clouds and COSP will play an important role in furthering this improvement," Klein said.
Climate models struggle to represent clouds accurately because the models lack the spatial resolution to fully represent clouds. Global climate models typically have a 100-kilometer resolution while meteorological models have a 20-kilometer range. However, to accurately represent clouds as seen in satellite measurements, the scale would need to be from the 500-meter resolution to 1-kilometer range.
"But those small scales are not practical for weather or global climate models," Klein said. "Our tool will better connect with what the satellites observe - how many clouds, their levels and their reflectivity."
The COSP is now used worldwide by most of the major models for climate and weather prediction, and it will play an important role in the evaluation of models that will be reviewed by the next report of the Intergovernmental Panel on Climate Change, Klein said.
The COSP allows for a meaningful comparison between model-simulated clouds and corresponding satellite observations. In other words, what would a satellite see if the atmosphere had the clouds of a climate model?
"COSP is an important and necessary development because modeled clouds cannot be directly compared with observational data; the model representation of clouds is not directly equivalent to what satellites are able to see," Klein explained. "The COSP eliminates significant ambiguities in the direct comparison of model simulations with satellite retrievals."
COSP includes a down-scaler that allows for large-scale climate models to estimate the clouds at the satellite-scale. The tool also allows modelers to diagnose how well models are able to simulate clouds as well as how climate change alters clouds. The tool already has revealed climate model limitations such as too many optically thick clouds, too few mid-level clouds and an overestimate of the frequency of precipitation. Additionally, COSP has shown that climate change leads to an increase in optical thickness and increases the altitude of high clouds and decreases the amount of low and mid-level clouds.
Other collaborators include: the UK's Hadley Centre, Université Pierre et Marie Curie; University of Washington; Monash University, University of Colorado; and the National Oceanic and Atmospheric Administration/Earth System Research Laboratory.
More information about the COSP appears in the August issue of the Bulletin of the American Meteorological Society.More Information
"Increase in atmospheric moisture tied to human activities," LLNL news release, Sept. 18, 2007
"Identification of Human-Induced Changes in Atmospheric Moisture Content," Proceedings of the National Academy of Sciences, Sept. 25, 2007
LLNL's Program for Climate Model Diagnosis and Intercomparison
Founded in 1952, Lawrence Livermore National Laboratory provides solutions to our nation's most important national security challenges through innovative science, engineering and technology. Lawrence Livermore National Laboratory is managed by Lawrence Livermore National Security, LLC for the U.S. Department of Energy's National Nuclear Security Administration.
Anne Stark | EurekAlert!
New research calculates capacity of North American forests to sequester carbon
16.07.2018 | University of California - Santa Cruz
Scientists discover Earth's youngest banded iron formation in western China
12.07.2018 | University of Alberta
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
16.07.2018 | Physics and Astronomy
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New computer modeling work shows that by 2100, if society wants to limit carbon dioxide in the atmosphere to less than 40 percent higher than it is today, the lowest cost option is to use every available means of reducing emissions. This includes more nuclear and renewable energy, choosing electricity over fossil fuels, reducing emissions through technologies that capture and store carbon dioxide, and even using forests to store carbon.
Researchers from the Joint Global Change Research Institute introduced the work, called the RCP 4.5 scenario, in a special July 29 online issue of the journal Climatic Change. The scenario is one of four that scientists will use worldwide to independently study how the climate might respond to different increases of greenhouse gases and how much of the sun's energy they trap in the atmosphere. It can also be used to study possible ways to slow climate change and adapt to it.
The team used the PNNL Global Change Assessment Model, or GCAM, to generate the scenario. GCAM uses market forces to reach a specified target by allowing global economics to put a price on carbon. And unlike similar models, it includes carbon stored in forests, causing forest acreage to increase -- even as energy systems change to include fuels generated from bioenergy crops and crop waste.
"The RCP 4.5 scenario assumes that action will be taken to limit emissions. Without any action, the emissions, and the heat trapped in the atmosphere, would be much higher, leading to more severe climate change," said lead author Allison Thomson, a scientist at JGCRI, a collaboration between the Department of Energy's Pacific Northwest National Laboratory in Richland, Wash., and the University of Maryland.
"This scenario and the other three produced in this project will provide a common thread for climate change research across many different science communities," Thomson said.
The Forested Future
Five years ago, the Intergovernmental Panel on Climate Change asked the climate science community to provide scenarios of greenhouse gas emissions and land use change to guide computer models that simulate potential changes to the Earth's climate.
Researchers decided on four possible targets that span a wide range of possible levels of man-made greenhouse gas emissions over the next century. These future scenarios are currently being used by climate modeling groups worldwide in a coordinated effort to compare models and advance the science of climate projections.
The researchers assigned each of the scenarios a specific target amount of the sun's energy that gets trapped in the atmosphere, a property called radiative forcing. Because of differences between the scenarios, each one will produce slightly different degrees of warming.
The RCP 4.5 scenario shoots for 4.5 Watts per square meters radiative forcing in 2100 and lets economics reveal how to achieve that goal the cheapest way possible. The scenario's 4.5 W/m2 means roughly 525 parts per million carbon dioxide in the atmosphere (currently, it hovers around 390 parts per million). It also means approximately 650 parts per million carbon dioxide-equivalents, which includes greenhouse gases besides carbon dioxide.
Unlike the other three scenarios, RCP 4.5 includes carbon in forests in the carbon market. This affects how people use land, as cutting down forests emits carbon dioxide but expanding forests stores it. An earlier modeling study showed that without placing such a value, forests could get cut down for use as biofuels and the land on which they stood used for crops.
The Greenhouse Race
Starting with the world as it looked in 2005 and setting the endpoint at 2100, the team let the model simulate the greenhouse gas emissions and land use change over the next century. They also ran the model without any explicit greenhouse gas control policy or carbon price to compare how such a future might turn out.
Without any emission controls, carbon dioxide concentrations in the atmosphere doubled by 2100. By design, RCP 4.5 limits them to about 35 percent higher than 2005 levels.
The conditions to limit emissions did not specify how to go about doing that, only that carbon from all sources had economic value. Under limiting conditions, carbon dioxide prices rose steadily until they reached $85 per ton of carbon dioxide by 2100, in 2005 dollars.
In the scenario, the price of carbon stimulated a rise in nuclear power and renewable energy use. Also, it became cheaper to implement technologies that capture and store emissions from fossil- and bio-fuel based electricity than to emit carbon dioxide. Buildings and industry became more energy efficient and used cleaner electricity for their energy needs.
Additionally, carbon dioxide emissions from man-made sources peaked around 2040 at 42 gigatons per year (currently, emissions are at 30 gigatons per year), decreased with about the same speed as they rose, then levelled out after 2080 at around 15 gigatons per year.
Also, the team converted the results of the scenario to match the resolution of the climate models that are using the results. That way, scientists can more easily integrate RCP 4.5 with climate models. Economies, for example, occur on national scales, but chemical reactions of gas in the air occur in much smaller spaces.
This change in scale to accommodate climate models reveals important regional details. For example, although globally methane emissions change little over the century, their geographic origins shift around. As the century wears on, South America and Africa put out more methane and the industrialized nations less.
In addition, the percentage of people's income that they're spending on food goes down even though food prices rise. The researchers attribute this result to a shift from agricultural practices with high carbon footprints to lower ones, as shown in previous work.
While introducing this scenario to climate researchers, the PNNL researchers provide comparisons to other scenarios with similar emissions limits, as well as to scenarios of the other three radiative forcing targets covered by this community activity. The special issue of Climatic Change features papers documenting those other three scenarios as well as several papers reviewing specific parts of the entire scenario exercise.
"It's very important that the climate community has this resource so that they all work from the same data. This common thread will help researchers and policymakers address the problems that climate change will bring us," said Thomson.
Data and results from RCP 4.5 studies are Open Access and are available from JGCRI's website here: http://www.globalchange.umd.edu/gcamrcp/
Reference: Allison M. Thomson, Katherine V. Calvin, Steven J. Smith, G. Page Kyle, April Volke, Pralit Patel, Sabrina Delgado-Arias, Ben Bond-Lamberty, Marshall A. Wise, Leon E. Clarke and James A. Edmonds, RCP 4.5: A Pathway for Stabilization of Radiative Forcing by 2100, Climatic Change, July 29, 2011, DOI 10.1007/s10584-011-0151-4 (http://www.springerlink.com/content/70114wmj1j12j4h2/).This work was supported by the U.S. Department of Energy Office of Science
The Joint Global Change Research Institute is a unique partnership formed in 2001 between the Department of Energy's Pacific Northwest National Laboratory and the University of Maryland. The PNNL staff associated with the center are world renowned for expertise in energy conservation and understanding of the interactions between climate, energy production and use, economic activity and the environment.
Mary Beckman | Newswise Science News
Further reports about: > Climate change > Human vaccine > Influence > PNNL > Pacific coral > RCP > atmosphere > bioenergy crop > carbon dioxide > carbon footprint > chemical reaction > climate models > computer model > gas emission > greenhouse gas > greenhouse gas emission > land use > renewable energy
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For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
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Authors: E.V. Timofeeva, D. Singh, W. Yu, D. France
Affilation: Argonne National Laboratory, United States
Pages: 404 - 407
Keywords: nanofluids, heat transfer, systems engineering, engineered fluids
Nanofluids are the new expanding area in nanotechnology, with applications as wide as biomedical, lubrication, thermal management, energy generation, energy conversion, and energy storage. Variety and unique characteristics of nanomaterials allow for engineering the multifunctional fluid media with new desired characteristics. High thermal conductivity is good for heat transfer, high specific heat advances the thermal energy storage, reduced surface tension improves evaporative/boiled cooling, etc. With nanomaterials one can not only improve the thermo-physical properties of liquids but also introduce additional functionality, such as novel applications of nanofluids in solar collectors, photovoltaic energy generation, and electric energy storage.An overview of systematic studies that address the complexity of nanofluid systems and advance the understanding of nanoscale contributions to viscosity, thermal conductivity, and cooling efficiency of nanofluids will be presented. The factors and mechanisms contributing to the fluid cooling efficiency will be discussed first, followed by a review of nanofluid engineering parameters and a brief analysis of their contributions to basic thermo-physical properties. The systems engineering approach will be used to describe how various nanofluid parameters contribute to the systems cooling performance. The latter also offers insights into the principles of the efficient nanofluid design for heat transfer and other novel applications.
Nanotech Conference Proceedings are now published in the TechConnect Briefs | <urn:uuid:7d085be3-a0fa-42a3-b0ee-4f1a9aaf3ae1> | 2.890625 | 347 | Academic Writing | Science & Tech. | -0.138462 | 95,516,309 |
And now, while studying the mechanism behind RNAi researchers at Oxford and Helsinki University have discovered that the functional core of a key enzyme (enzymes are proteins which promote biochemical reactions in the body) involved in the formation of RNAi molecules is striking similar to an enzyme involved in gene expression.
The research, published in the journal "Public Library of Science Biology", supports the idea that the two enzymes have a common ancestor and gives weight to the theory that life started as self-replicating RNA molecules in a RNA world (as opposed to the present world where molecules of DNA are the basis of life).
In fact, we live in a DNA world, as genes are segments of DNA, and it is the information contained in the genes of an organism that, when translated into proteins, makes up the blueprint for the body structure and function. This process, the expression of genes into proteins, is comprised of two steps: the first by which genetic information in DNA is converted into RNA and the second which is the synthesis of proteins based on the information/instructions contained in the newly made RNA (DNA ? RNA ? protein).
But there is a dent in this apparently perfect process. In fact, for a long time scientists have been puzzled why approximately 32% of the human genome/DNA, although transformed into RNA, does not lead to protein production (DNA ? RNA ? no protein)? So why would this huge amount of “junk” RNA keep being formed instead of being eliminated during evolution? After all, a basic rule of life is that any reaction that costs energy and is not advantageous for the individual must be eliminated. What recent research unveiled is that RNA is a much more multifaceted molecule than previously thought, and some of that “junk” RNA actually plays an important role in gene regulation. One such example is RNAi, a RNA that is capable of blocking the activity of specific genes.
And it was while studying the mechanisms behind RNAi, that Paula S. Salgado, Jonathan M. Grimes and colleagues discovered that the functional core of an enzyme involved in the formation of short RNAi molecules from other RNA molecules (RNA? RNA), was remarkably similar to the one that mediates the formation of RNA from DNA (DNA ? RNA) during the first step of gene expression. This striking similarity suggested a common ancestor and further analysis seemed to indicate that the enzyme involved in the RNAi process had appeared before and so would probably be more similar structurally to the common ancestor.
These results support the idea of life starting in a (RNA) world where self-replicating (RNA?RNA) multifunctional RNA molecules evolved (as well as the enzymes mediating the process) into the present situation where genetic information is contained instead on DNA. In fact, although RNA is chemically similar to DNA it has, as the “originater” of life, two major advantages over the latter molecule: 1- it is easily synthesised from non-complex blocks so it had higher possibility of occurring spontaneously and 2 - it is easy to imagine that it could evolve into DNA, which by being a much more stable molecule would then take over. Furthermore, the idea of a primitive RNA world, if proved, could solve one of biggest conundrums on the origin of life: if life needs both DNA as a source of genetic information and proteins to drive life’s chemical reactions how could have one appeared first without the other? Some scientists believe that the answer lies in this ancient RNA molecule which was capable of supporting life reactions and also contained life’s genetic blueprint and whose existence seems to be consistent with the findings of Salgado, Grimes and colleagues.
In this way, Salgado’s work sheds light not only on the mechanism behind this extremely interesting and important process that is RNAi, but can also help to understand better how life began on earth.Piece researched and written by:
Catarina Amorim | alfa
NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation
Pollen taxi for bacteria
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For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
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18.07.2018 | Health and Medicine | <urn:uuid:f64badd9-1421-4e39-9237-92c80ad030b5> | 3.484375 | 1,433 | Content Listing | Science & Tech. | 39.755162 | 95,516,324 |
The bottom of the deep sea is largely deserted. Oases occur for example at cold seeps where water transports dissolved elements from the seabed: Specialized microbes convert methane and sulfate from sea water to hydrogen sulfide releasing carbon dioxide.
This is a crab on a bacterial mat at mud volcano Mound 12, documented by a deep-sea observatory.
Credit: GEOMAR Helmholtz Centre for Ocean Research Kiel
Highly adapted bacteria, many of which live in symbiosis with worms and clams, use the hydrogen sulfide for their growth. In their cells, they incorporate carbon originating from the chemical reaction of methane. "The co-existence of organisms that have settled at the cold seeps is already well understood", says Dr. Peter Linke. The biologist at GEOMAR Helmholtz Centre for Ocean Research Kiel is lead author of the publication in the online journal PLOS ONE together with Dr. Helge Niemann from the University of Basel.
"We could give evidence that crabs subsist on the methane seeps. Thus, we came a bit closer to answering the question of which organisms benefit from the cold seeps: Versatile animals living on a mixed diet do so as well. "
In dives with the submersible ALVIN and the underwater robot QUEST off the coast of Costa Rica in the summer of 2005, the researchers observed lithodid crabs grazing at bacterial mats at a methane seep in the vicinity of the mud volcano "Mound 12". "As far as we know, deep-sea crabs feeding on bacterial mats were discovered only one single time before," Linke states.
"Our team was the first one to also generate a photographic documentation over a longer period which allows scientific interpretations." For this purpose, a deep-sea observatory was equipped with a camera and placed above a bacterial mat. During a period of about 400 hours, the camera automatically took a picture every 30 minutes. "On 184 images, crabs were seen crawling over the bacteria and apparently grazed the bacterial "lawn", Niemann describes the observations. "Afterwards, it took a few hours until the animals returned, so that new bacteria could grow."
With the submersible ALVIN, the marine biologists brought one of the crabs onboard their research vessel ATLANTIS. For the comparison with the bacteria, the diving robot QUEST took short sediment cores from the sea floor from the METEOR. "DNA and isotopic analyses at Max Planck Institute for Marine Microbiology later showed that the crabs actually feed on the bacterial mat and took up large amounts of chemically-produced carbon. In the body cells, we have also found traces of carbon, which was formed under the influence of light through photosynthesis", summarizes main author Niemann. "Therefore, we assume that cold seeps make an important but not the only contribution to the diet of migratory animals on the ocean floor and in this way enters into carbon, which is produced by chemosynthesis of methane in the marine food web."
Original publication: Niemann, H.; Linke, P.; Knittel, K.; MacPherson, E.; Boetius, A.; Brückmann, W.; Larvik, G.; Wallmann, K.; Schacht, U.; Omoregie, E.; Hilton, D.; Brown, K.; Rehder, G.: Methane-carbon flow into the benthic food web at cold seeps – a case study from the Costa Rica subduction zone. http://dx.plos.org/10.1371/journal.pone.0074894
Maike Nicolai | EurekAlert!
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For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
19.07.2018 | Earth Sciences
19.07.2018 | Power and Electrical Engineering
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Rather than the old Western yarn of “water is for fighting,” can a focus on historical conservation cooperation teach us anything?
There are between 200,000 and 500,000 sage grouse in the West, down from a peak population of about 16 million.
The Navajo Nation joins forces with Colorado, New Mexico and three other tribes to help recover endangered fish species.
As Garden of the Gods, Conundrum Hot Springs and Hanging Lake experience record visitors, park officials are scrambling for solutions.
When unprepared owners surrender their captive wolves and wolf-dogs, this southern Colorado sanctuary takes them in.
While Costilla County has only 3,524 residents, due to its unique history it has more than 45,000 landowners, mostly absentee.
Wolves and wolf-dogs born into captivity face a bleak future. The Mission: Wolf sanctuary gives them a home.
A year into his tenure, Secretary Ryan Zinke has emerged as the point person for the administration's goal of American "energy dominance."
This is the eighth consecutive year Colorado College has released the Conservation in the West Poll. | <urn:uuid:d3d2d2c5-6c98-4d61-a58f-5a80e1a600fa> | 2.828125 | 224 | Content Listing | Science & Tech. | 41.679908 | 95,516,349 |
Reddening map of the Large Magellanic Cloud bar region *
Indian Institute of Astrophysics, II Block, Koramangala, Bangalore 560034, India e-mail: email@example.com
Accepted: 16 September 2004
reddening values for 1123 locations in the bar region of the Large Magellanic Cloud are presented. V, I photometry of red clump stars identified in the Optical Gravitational Lensing Experiment II catalogue of LMC were used to estimate reddening. values were estimated as the difference between observed and the characteristic values of for the red clump population in a given region. It is found that most of the regions in the bar have reddening values less than 0.1 mag with only a few locations having values more than 0.2 mag. The eastern side of the bar is found to be more reddened when compared to the western side, with similar and relatively small values for differential reddening as in most parts of the bar. Increased reddening in the eastern end of the bar could be caused by a small fraction of the H I clouds in the line of sight. A high density of HI clouds located in the eastern end of the bar should have caused very high reddening in these regions, whereas only a relatively small increase in the reddening is estimated. This indicates that most of the H I clouds in this direction are likely to be located behind the bar.
Key words: galaxies: Magellanic Clouds / dust, extinction
© ESO, 2005 | <urn:uuid:2eda9bdb-968e-47ca-a879-08532b6d185d> | 2.53125 | 313 | Academic Writing | Science & Tech. | 44.109024 | 95,516,384 |
Beijing: China's manned deep sea submersible Jiaolong collected 17 items of deep-sea living beings from the southwestern Indian Ocean on Wednesday.
Of the 17 samples collected, two of them were unknown for scientists.
With a size similar to a regular sea cucumber, the first mysterious creature broke into three parts when it was taken to the vessel in the south west Indian Ocean, according to official media reports.
Since the living being was transparent, scientists could see its blue and brown viscera clearly.
“This might be a special kind of sea cucumber, but we need to make sure after further analysis in labs,” Lu Bo, a scientist with the Second Institute of Oceanography of the State Oceanic Administration (SOA), was quoted as saying to state-run Xinhua news agency.
The second weird creature, which looks like a small pink snake, is 330 centimeters long and three centimeters wide and is completely unknown for the scientists. Scientists said two bubbles appeared in its body due to pressure change.
“These two living beings might be new species but we can't be certain with limited tools and data on the ship,” Lu Bo said.
The Jiaolong also collected 15 deep-sea shrimps, water and sulfide weighing 6.9 kilograms.
Earlier, Jiaolong which started the operations few weeks ago already secured contracts to explore Indian Ocean for polymetallic sulphide ore and its research vessel has discovered two hydrothermal areas and four hydrothermal anomaly areas in February this year in southwest Indian Ocean.
China also has obtained exclusive rights to prospect in a 75,000-square-km polymetallic nodule ore deposit in the east Pacific Ocean in 2001.
The Jiaolong, which reached a maximum depth of 7,062 meters in the Mariana Trench in June 2012, is on a 120-day expedition to study polymetallic sulfide, biological diversity, hydrothermal microbes and genetic resources in the southwest Indian Ocean.
(With PTI inputs) | <urn:uuid:1cf592fd-6970-46fa-8bb1-ea9bdee9bc66> | 3.125 | 425 | News Article | Science & Tech. | 40.84006 | 95,516,414 |
MySQL supports foreign keys, which let you cross-reference
related data across tables, and
constraints, which help keep this spread-out data
consistent. The essential syntax for a foreign key constraint
definition in a
CREATE TABLE or
ALTER TABLE statement looks like
[CONSTRAINT [symbol]] FOREIGN KEY [index_name] (index_col_name, ...) REFERENCES tbl_name (index_col_name,...) [ON DELETE reference_option] [ON UPDATE reference_option] reference_option: RESTRICT | CASCADE | SET NULL | NO ACTION | SET DEFAULT
index_name represents a foreign key
index_name value is ignored
if there is already an explicitly defined index on the child
table that can support the foreign key. Otherwise, MySQL
implicitly creates a foreign key index that is named according
to the following rules:
If defined, the
symbolvalue is used. Otherwise, the
index_namevalue is used.
If neither a
index_nameis defined, the foreign key index name is generated using the name of the referencing foreign key column.
index_name value must be unique in
Foreign keys definitions are subject to the following conditions:
Foreign key relationships involve a parent table that holds the central data values, and a child table with identical values pointing back to its parent. The
FOREIGN KEYclause is specified in the child table. The parent and child tables must use the same storage engine. They must not be
In MySQL 8.0, creation of a foreign key constraint requires the
REFERENCESprivilege for the parent table.
Corresponding columns in the foreign key and the referenced key must have similar data types. The size and sign of integer types must be the same. The length of string types need not be the same. For nonbinary (character) string columns, the character set and collation must be the same.
foreign_key_checksis enabled, which is the default setting, character set conversion is not permitted on tables that include a character string column used in a foreign key constraint. The workaround is described in Section 13.1.8, “ALTER TABLE Syntax”.
MySQL requires indexes on foreign keys and referenced keys so that foreign key checks can be fast and not require a table scan. In the referencing table, there must be an index where the foreign key columns are listed as the first columns in the same order. Such an index is created on the referencing table automatically if it does not exist. This index might be silently dropped later, if you create another index that can be used to enforce the foreign key constraint.
index_name, if given, is used as described previously.
InnoDBpermits a foreign key to reference any column or group of columns. However, in the referenced table, there must be an index where the referenced columns are listed as the first columns in the same order.
Index prefixes on foreign key columns are not supported. One consequence of this is that
TEXTcolumns cannot be included in a foreign key because indexes on those columns must always include a prefix length.
CONSTRAINTclause is given, the
symbolvalue, if used, must be unique in the database. A duplicate
symbolwill result in an error similar to: ERROR 1022 (2300): Can't write; duplicate key in table '#sql- 464_1'. If the clause is not given, or a
symbolis not included following the
CONSTRAINTkeyword, a name for the constraint is created automatically.
InnoDBdoes not currently support foreign keys for tables with user-defined partitioning. This includes both parent and child tables.
Additional aspects of
FOREIGN KEY constraint
usage are described under the following topics in this section:
This section describes how foreign keys help guarantee referential integrity.
For storage engines supporting foreign keys, MySQL rejects any
UPDATE operation that attempts
to create a foreign key value in a child table if there is no
a matching candidate key value in the parent table.
DELETE operation affects a key
value in the parent table that has matching rows in the child
table, the result depends on the referential
action specified using
ON DELETE subclauses of the
FOREIGN KEY clause. MySQL supports five
options regarding the action to be taken, listed here:
CASCADE: Delete or update the row from the parent table, and automatically delete or update the matching rows in the child table. Both
ON DELETE CASCADEand
ON UPDATE CASCADEare supported. Between two tables, do not define several
ON UPDATE CASCADEclauses that act on the same column in the parent table or in the child table.
FOREIGN KEYclause is defined on both tables in a foreign key relationship, making both tables a parent and child, an
ON UPDATE CASCADEor
ON DELETE CASCADEsubclause defined for one
FOREIGN KEYclause must be defined for the other in order for cascading operations to succeed. If an
ON UPDATE CASCADEor
ON DELETE CASCADEsubclause is only defined for one
FOREIGN KEYclause, cascading operations fail with an error.Note
Cascaded foreign key actions do not activate triggers.
SET NULL: Delete or update the row from the parent table, and set the foreign key column or columns in the child table to
ON DELETE SET NULLand
ON UPDATE SET NULLclauses are supported.
If you specify a
SET NULLaction, make sure that you have not declared the columns in the child table as
RESTRICT: Rejects the delete or update operation for the parent table. Specifying
NO ACTION) is the same as omitting the
NO ACTION: A keyword from standard SQL. In MySQL, equivalent to
RESTRICT. The MySQL Server rejects the delete or update operation for the parent table if there is a related foreign key value in the referenced table. Some database systems have deferred checks, and
NO ACTIONis a deferred check. In MySQL, foreign key constraints are checked immediately, so
NO ACTIONis the same as
SET DEFAULT: This action is recognized by the MySQL parser, but
InnoDBrejects table definitions containing
ON DELETE SET DEFAULTor
ON UPDATE SET DEFAULTclauses.
ON DELETE or
UPDATE that is not specified, the default action is
MySQL supports foreign key references between one column and another within a table. (A column cannot have a foreign key reference to itself.) In these cases, “child table records” really refers to dependent records within the same table.
A foreign key constraint on a stored generated column cannot
ON UPDATE CASCADE,
ON UPDATE SET NULL,
ON DELETE SET DEFAULT, or
UPDATE SET DEFAULT.
A foreign key constraint cannot reference a virtual generated column.
InnoDB restrictions related to foreign
keys and generated columns, see
Section 22.214.171.124, “InnoDB and FOREIGN KEY Constraints”.
Here is a simple example that relates
through a single-column foreign key:
CREATE TABLE parent ( id INT NOT NULL, PRIMARY KEY (id) ) ENGINE=INNODB; CREATE TABLE child ( id INT, parent_id INT, INDEX par_ind (parent_id), FOREIGN KEY (parent_id) REFERENCES parent(id) ON DELETE CASCADE ) ENGINE=INNODB;
A more complex example in which a
product_order table has foreign keys for
two other tables. One foreign key references a two-column
index in the
product table. The other
references a single-column index in the
CREATE TABLE product ( category INT NOT NULL, id INT NOT NULL, price DECIMAL, PRIMARY KEY(category, id) ) ENGINE=INNODB; CREATE TABLE customer ( id INT NOT NULL, PRIMARY KEY (id) ) ENGINE=INNODB; CREATE TABLE product_order ( no INT NOT NULL AUTO_INCREMENT, product_category INT NOT NULL, product_id INT NOT NULL, customer_id INT NOT NULL, PRIMARY KEY(no), INDEX (product_category, product_id), INDEX (customer_id), FOREIGN KEY (product_category, product_id) REFERENCES product(category, id) ON UPDATE CASCADE ON DELETE RESTRICT, FOREIGN KEY (customer_id) REFERENCES customer(id) ) ENGINE=INNODB;
You can add a new foreign key constraint to an existing table
ALTER TABLE. The
syntax relating to foreign keys for this statement is shown
ALTER TABLE tbl_name ADD [CONSTRAINT [symbol]] FOREIGN KEY [index_name] (index_col_name, ...) REFERENCES tbl_name (index_col_name,...) [ON DELETE reference_option] [ON UPDATE reference_option]
The foreign key can be self referential (referring to the same
table). When you add a foreign key constraint to a table using
ALTER TABLE, remember
to create the required indexes first.
You can also use
ALTER TABLE to
drop foreign keys, using the syntax shown here:
ALTER TABLE tbl_name DROP FOREIGN KEY fk_symbol;
FOREIGN KEY clause included a
CONSTRAINT name when you created the
foreign key, you can refer to that name to drop the foreign
key. Otherwise, the
is generated internally when the foreign key is created. To
find out the symbol value when you want to drop a foreign key,
SHOW CREATE TABLE
statement, as shown here:
mysql> SHOW CREATE TABLE ibtest11c\G *************************** 1. row *************************** Table: ibtest11c Create Table: CREATE TABLE `ibtest11c` ( `A` int(11) NOT NULL auto_increment, `D` int(11) NOT NULL default '0', `B` varchar(200) NOT NULL default '', `C` varchar(175) default NULL, PRIMARY KEY (`A`,`D`,`B`), KEY `B` (`B`,`C`), KEY `C` (`C`), CONSTRAINT `0_38775` FOREIGN KEY (`A`, `D`) REFERENCES `ibtest11a` (`A`, `D`) ON DELETE CASCADE ON UPDATE CASCADE, CONSTRAINT `0_38776` FOREIGN KEY (`B`, `C`) REFERENCES `ibtest11a` (`B`, `C`) ON DELETE CASCADE ON UPDATE CASCADE ) ENGINE=INNODB CHARSET=utf8mb4 1 row in set (0.01 sec) mysql> ALTER TABLE ibtest11c DROP FOREIGN KEY `0_38775`;
In MySQL 8.0, the server prohibits changes to
foreign key columns with the potential to cause loss of
referential integrity. A workaround is to use
ALTER TABLE ...
DROP FOREIGN KEY before changing the column
ALTER TABLE ...
ADD FOREIGN KEY afterward.
Table and column identifiers in a
FOREIGN KEY ...
REFERENCES ... clause can be quoted within backticks
`). Alternatively, double quotation marks
") can be used if the
ANSI_QUOTES SQL mode is
enabled. The setting of the
variable is also taken into account.
You can view a child table's foreign key definitions as
part of the output of the
SHOW CREATE TABLE tbl_name;
You can also obtain information about foreign keys by querying
mysqldump produces correct definitions of tables in the dump file, including the foreign keys for child tables.
To make it easier to reload dump files for tables that have
foreign key relationships, mysqldump
automatically includes a statement in the dump output to set
foreign_key_checks to 0. This
avoids problems with tables having to be reloaded in a
particular order when the dump is reloaded. It is also
possible to set this variable manually:
mysql> SET foreign_key_checks = 0; mysql> SOURCE dump_file_name; mysql> SET foreign_key_checks = 1;
This enables you to import the tables in any order if the dump
file contains tables that are not correctly ordered for
foreign keys. It also speeds up the import operation. Setting
foreign_key_checks to 0 can
also be useful for ignoring foreign key constraints during
LOAD DATA and
ALTER TABLE operations.
However, even if
0, MySQL does not permit the creation of a foreign
key constraint where a column references a nonmatching column
type. Also, if a table has foreign key constraints,
ALTER TABLE cannot be used to
alter the table to use another storage engine. To change the
storage engine, you must drop any foreign key constraints
You cannot issue
DROP TABLE for
a table that is referenced by a
constraint, unless you do
SET foreign_key_checks =
0. When you drop a table, any constraints that were
defined in the statement used to create that table are also
If you re-create a table that was dropped, it must have a
definition that conforms to the foreign key constraints
referencing it. It must have the correct column names and
types, and it must have indexes on the referenced keys, as
stated earlier. If these are not satisfied, MySQL returns
Error 1005 and refers to Error 150 in the error message, which
means that a foreign key constraint was not correctly formed.
Similarly, if an
fails due to Error 150, this means that a foreign key
definition would be incorrectly formed for the altered table.
InnoDB tables, you can obtain a
detailed explanation of the most recent
InnoDB foreign key error in the MySQL
Server, by checking the output of
MySQL extends metadata locks, as necessary, to tables that are related by a foreign key constraint. Extending metadata locks prevents conflicting DML and DDL operations from executing concurrently on related tables. This feature also enables updates to foreign key metadata when a parent table is modified. In earlier MySQL releases, foreign key metadata, which is owned by the child table, could not be updated safely.
If a table is locked explicitly with
TABLES, any tables related by a foreign key
constraint are opened and locked implicitly. For foreign key
checks, a shared read-only lock
READ) is taken on related tables. For cascading
updates, a shared-nothing write lock
WRITE) is taken on related tables that are involved
in the operation.
For users familiar with the ANSI/ISO SQL Standard, please note
that no storage engine, including
recognizes or enforces the
used in referential-integrity constraint definitions. Use of
MATCH clause will not have the
specified effect, and also causes
ON UPDATE clauses to be ignored. For
these reasons, specifying
MATCH should be
MATCH clause in the SQL standard
NULL values in a composite
(multiple-column) foreign key are handled when comparing to a
primary key. MySQL essentially implements the semantics
MATCH SIMPLE, which permit a
foreign key to be all or partially
that case, the (child table) row containing such a foreign key
is permitted to be inserted, and does not match any row in the
referenced (parent) table. It is possible to implement other
semantics using triggers.
Additionally, MySQL requires that the referenced columns be
indexed for performance reasons. However, the system does not
enforce a requirement that the referenced columns be
UNIQUE or be declared
NULL. The handling of foreign key references to
nonunique keys or keys that contain
values is not well defined for operations such as
CASCADE. You are advised to use foreign keys that
Furthermore, MySQL parses but ignores “inline
REFERENCES specifications” (as
defined in the SQL standard) where the references are defined
as part of the column specification. MySQL accepts
REFERENCES clauses only when specified as
part of a separate
specification. For storage engines that do not support foreign
keys (such as
Server parses and ignores foreign key specifications.
table identifies the key columns that have constraints.
Metadata specific to
InnoDB foreign keys is
found in the
In the event of a foreign key error involving
InnoDB tables (usually Error 150 in the
MySQL Server), information about the most recent
InnoDB foreign key error can be obtained by
ENGINE INNODB STATUS output.
If a user has table-level privileges for all parent tables,
messages for foreign key operations expose information about
parent tables. If a user does not have table-level
privileges for all parent tables, more generic error
messages are displayed instead
An exception is that, for stored programs defined to execute
DEFINER privileges, the user against
which privileges are assessed is the user in the program
DEFINER clause, not the invoking user. If
that user has table-level parent table privileges, parent
table information is still displayed. In this case, it is
the responsibility of the stored program creator to hide the
information by including appropriate condition handlers. | <urn:uuid:9ce9e68c-8c6c-44ba-9659-c369b7332bb6> | 3.15625 | 3,809 | Documentation | Software Dev. | 37.436061 | 95,516,417 |
After two years of extensive upgrades, the Large Hadron Collider (LHC) was warming up on March 21 for another round of experiments when a circuit controlling one of its massive magnets shorted out. Dismayed, scientists began repairing the equipment, hoping for a short delay. Just yesterday, CERN announced that the LHC could restart within days.
Then the unexpected happened. As physicists were testing the repairs by zipping a few spare protons around the 17 mile loop, the CMS detector picked up something unusual. The team feverishly pored over the data, and ultimately came to an unlikely conclusion—in their tests, they had accidentally created a rainbow universe.
“Rainbow universes were pure speculation before this happened,” said Jessica Czerniski, the CERN physicist who was overseeing the warm-up procedures. “We had some solid math backing us up, of course, but none of us ever dreamed we would live to see this day.”
First proposed back in the early 2000s, the theory of rainbow gravity posits that different wavelengths of light are affected by gravity in different ways. Rainbow universes are thought to be a natural result of rainbow gravity, but with the peculiar qualities of not having distinct beginnings. In other words, rainbow universes have been around since forever, which has physicists stumped over the “creation” at the LHC.
“When I first saw the paper posted on the arXiv [a site for scholarly publications], I almost spit out my coffee,” said Randall Pattinson, a professor of physics at the Princeton University. “Rainbow gravity has some real physics behind it, but actually seeing evidence of it? It’s like finding an original edition Lisa Frank Trapper Keeper that your daughter wanted for her birthday. It’s almost too good to be true.”
Technicians close to the CMS detector reported hearing a loud noise, something of a cross between screeching metal and tearing cloth. In a thick haze that hung over the magnet, initially thought to be smoke from the short circuit, they saw a shimmering halo that spanned the full spectrum of visible light which vanished after a few seconds. Scientists studying the CMS data later confirmed the anomaly lasted for about 2.6 seconds.
Czerniski and her team would like to repeat the conditions that led to the appearance of the rainbow universe, though only after carefully analyzing the current CMS data. “We’d like to ensure that there aren’t any unanticipated consequences from attempting to create a more stable version of the rainbow universe,” she said, acknowledging that CERN is aware of the public’s concerns over its experiments. (When the LHC was first started, some people feared the powerful accelerator would create a black hole here on Earth.)
Among the curiosities Czerniski and her colleagues need to sort out is an artifact in the data that, when recreated in three-dimensions, appears to be the ghostly outline of a dolphin. At first they thought it was merely the computer’s desktop wallpaper bleeding through a transparent window, but after confirming the terminal’s settings, they dove deeper into the data. Subsequent analysis suggested the apparition is real as it registered at five sigma.
Should the CERN team be successful in creating another rainbow universe, proof of a rainbow gravity could force physicists to rethink the origins of the universe—the Big Bang theory, for example, would likely be thrown out. But such a confirmation could also finally bridge general relativity with quantum mechanics.
“We’re literally on the edge of our seats,” Czerniski said. “If this pans out, maybe we’ll finally be able to convince the international community to build the space-based particle accelerator we’ve been hoping for. There’s a perfect spot on the International Space Station for it—right next to the dolphin module that was installed last year.”
The idea of an ordered and elegant universe is a lovely one. One worth clinging to. But you don't need religion to appreciate the ordered existence. It's not just an idea. It's reality. We're discovering the hidden orders of the universe every day. The inverse square law of gravitation is amazing. Fractals, the theory of relativity, the genome: these are magnificently beautiful constructs.
Send a text message from a computer to a mobile phone
As of 2018, we have switched our mobile phone carrier from Verizon to T-Mobile. Hello, unlimited data! And less expensive to boot! To send a text from a computer to a mobile phone on T-Mobile, use the following format. | <urn:uuid:a2c3942d-a735-49f2-a86a-f710e96255a9> | 2.671875 | 974 | Personal Blog | Science & Tech. | 43.032345 | 95,516,423 |