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Engineers Devise a Way to Harvest Wind Energy from TreesThis entry was posted
in Education, News At A Glance and tagged piezoelectric system, tree energy. Bookmark the permalink.
Harvesting electrical power from vibrations or other mechanical stress is pretty easy. Turns out all it really takes is a bit of crystal or ceramic material and a couple of wires and, there you go, piezoelectricity. As stress is applied to the material, charge accumulates, which can then be shuttled away to do useful work. The classic example is an electric lighter, in which a spring-loaded hammer smacks a crystal, producing a spark.
We’re surrounded by this sort of ambient energy. The whole universe is just a big mess of force and stress. The tapping of my fingers on the keyboard now could theoretically be used to generate voltage. In fact, the idea is already under patent: a battery-charging keyboard cover. But the idea scales way up too: Imagine the sway of a skyscraper or the trembling of an entire forest in the wind.
The second example is the heart of a piezoelectric system described in a new paper in the Journal of Sound and Vibration courtesy of engineers at Ohio State’s Laboratory of Sound and Vibration Research. The basic idea behind the energy harvesting platform: exploit the natural internal resonances of trees within tiny artificial forests capable of generating enough voltage to power sensors and structural monitoring systems.
The piezoelectric power produced by the flexing of a tree in some wind isn’t quite on par with that produced by a proper windmill. Part of the problem is that a vibration-based piezoelectric energy harvesting scheme is necessarily limited in the frequency range of vibrations that it can usefully convert into power. Different ranges demand different material properties. Unfortunately for our energy needs, wind is a pretty random thing.
Image: Harne et al
What the Ohio State group, led by mechanical and aerospace engineering professor Ryan Harne, found is that it may be possible after all to convert relatively random range of vibration frequencies to useful energy by exploiting the natural resonant frequency of tree-like structures. This resonant frequency can be imagined as a kind of frequency wall or barrier that absorbs and stores the vibrational energies of the higher frequencies, sort of like how small riffles on the surface of a body of water get soaked up into larger swells.
The paper uses a foot-bridge metaphor for resonant frequency. Imagine a crowd of people stomping across a bridge. All of the walkers are stepping with different frequencies, but some match that of the resonant frequency of the bridge and so this larger, much lower frequency is amplified. The stepping frequencies might all average out, constituting something like white noise, but that’s not quite how it works here: Some of that stepping energy is captured by the bridge because of its resonance.
This is sort of how it goes in trees—a breeze might whip a leaf or small branch around like crazy, but that power is also being subsumed into the larger, much more powerful low-frequency sway of the tree itself.
Harne’s initial mathematical finding that it is indeed possible to capture useful energy from random or random-ish wind (“noisy” wind) input was then tested out using an actual tree-like L-shaped construction of small steel beams wrapped in polyvinylidene fluoride (PVDF), a piezoelectric material. They managed to produce about 2 V.
It’s mostly a proof of concept or rather a disproof of the assumption that wind vibrations can’t be usefully harvested. Don’t expect tiny metal forests to power cities, but it’s still a cool idea.
read more original article Motherboard
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Chapter 11 Simple Harmonic Motion. Chapter 11. Hooke’s Law. One type of periodic motion is the motion of a mass attached to a spring. The direction of the force acting on the mass ( F elastic ) is always opposite the direction of the mass’s displacement from equilibrium ( x = 0).
Felastic = –kx
spring force = –(spring constant displacement)
Section 3 Properties of WavesWave Motion
v = f
The most famous and conspicuous supernova remnant. The Crab Nebula is the centuries-old wreckage of a stellar explosion, or supernova, first noted by Chinese astronomers on July 4, 1054, and that reached a peak magnitude of -6 (about four times brighter than Venus). According to the Chinese records, it was visible in daylight for 23 days and in the night sky to the unaided eye for 653 days. Petroglyphs found in Navaho Canyon and White Mesa (both Arizona) and in the Chaco Canyon National Park (New Mexico) appear to be depictions of the event by Anasazi Indian artists. The Crab Nebula lies about 6,300 light-years away in the constellation Taurus, measures roughly 10 light-years across, and is expanding at an average speed of 1,800 km/s. Surprisingly, its expansion rate seems to be accelerating, driven by radiation from the central pulsar. Its luminosity at visible wavelengths exceeds 1,000 times that of the Sun | <urn:uuid:fb0fc466-44c6-4ece-be81-f2952724bc32> | 3.734375 | 299 | Truncated | Science & Tech. | 51.334659 | 95,554,950 |
Dr. Miriam Douglass
Dr. Martin McClinton
Learners examine how melting, vaporization, and sublimation require energy input while freezing and condensation release energy.
The Solid State
By Debbie McClinton, Dr. Miriam Douglass, Dr. Martin McClinton
In this well-illustrated object, learners examine the structures and properties of the four types of solids: molecular, metallic, ionic, and covalent network. Five interactive questions are provided.
By Terry Bartelt
Learners view an animated presentation showing how the pH level of a cleaning solution is controlled in a closed-loop system in a manufacturing setting. A quiz completes the activity.
The Kinetic Theory of Gases
By Dr. Miriam Douglass, Dr. Martin McClinton
In this animated activity, learners examine what gases are composed of and how their particles interact. They also consider several assumptions that form the basis for the Kinetic Theory of Gases.
Learning the Elements of the Periodic Table by Name or Symbol
By Mona Wenrich
Students practice identifying common elements from the periodic table by name or symbol.
Creative Commons Attribution-NonCommercial 4.0 International License.
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Chandra X-ray Image of Tychos Supernova Remnant. Credit: NASA/CXC/Rutgers/J.Warren & J.Hughes et al.
Astronomers have found compelling evidence that a supernova shock wave has produced a large amount of cosmic rays, particles of mysterious origin that constantly bombard the Earth. This discovery, made with NASA’s Chandra X-ray Observatory, supports theoretical arguments that shock waves from stellar explosions may be a primary source of cosmic rays.
This finding is important for understanding the origin of cosmic rays, which are atomic nuclei that strike the Earth’s atmosphere with very high energies. Scientists believe that some are produced by flares on the Sun, and others by similar events on other stars, or pulsars or black hole accretion disks. But, one of the prime suspects has been supernova shock waves. Now, a team of astronomers has used Chandra observations of Tycho’s supernova remnant to strengthen the case for this explanation.
"With only a single object involved we can’t state with confidence that supernova shock waves are the primary source of cosmic rays," said John P. Hughes of Rutgers University in Piscataway, New Jersey, and coauthor of a report to be published in an upcoming issue of The Astrophysical Journal. "What we have done is present solid evidence that the shock wave in at least one supernova remnant has accelerated nuclei to cosmic ray energies."
In the year 1572, the Danish astronomer Tycho Brahe observed and studied the sudden appearance of a bright "new star" in the constellation Cassiopeia. Now known as Tycho’s supernova remnant, the event created a sensation in Tycho’s time because it exploded the myth that stars never change.
Megan Watzke | EurekAlert!
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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.
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This article needs attention from an expert in Physics. The specific problem is: Article needs more explanation/summary for lower-level audiences, as well as updates for current results (see talk page).(April 2018)
The Lieb-Robinson bound is a theoretical upper limit on the speed at which information can propagate in non-relativistic quantum systems. It demonstrates that information cannot travel instantaneously in quantum theory, even when the relativity limits of the speed of light are ignored. The existence of such a finite speed was discovered mathematically by Elliott Lieb and Derek William Robinson in 1972. It turns the locality properties of physical systems into the existence of, and upper bound for this speed. The bound is now known as the Lieb-Robinson bound and the speed is known as the Lieb-Robinson velocity. This velocity is always finite but not universal, depending on the details of the system under consideration.
In the study of quantum systems such as quantum optics, quantum information theory, atomic physics, and condensed matter physics, it is important to know that there is a finite speed with which information can propagate. The theory of relativity shows that no information, or anything else for that matter, can travel faster than the speed of light. When non-relativistic mechanics is considered, however, (Newton's equations of motion or Schrödinger's equation of quantum mechanics) it had been thought that there is then no limitation to the speed of propagation of information. This is not so for certain kinds of quantum systems of atoms arranged in a lattice, often called quantum spin systems. This is important conceptually and practically, because it means that, for short periods of time, distant parts of a system act independently.
One of the practical applications of Lieb-Robinson bounds is quantum computing. Current proposals to construct quantum computers built out of atomic-like units mostly rely on the existence of this finite speed of propagation to protect against too rapid dispersal of information.
- 1 Set up
- 2 Improvements of the Lieb-Robinson bounds
- 3 Some applications
- 4 Experiments
- 5 References
To define the bound, it is necessary to first describe basic facts about quantum mechanical systems composed of several units, each with a finite dimensional Hilbert space.
Lieb-Robinson bounds are considered on a -dimensional lattice ( or ) , such as the square lattice .
A Hilbert space of states is associated with each point . The dimension of this space is finite, but this was generalized in 2008 to include infinite dimensions (see below). This is called quantum spin system.
For every finite subset of the lattice, , the associated Hilbert space is given by the tensor product
is a subspace of if .
When is finite dimensional, choose a finite basis of operators that span the set of linear operators on . Then any observable on can be written as a sum of basis operators on .
The Hamiltonian of the system is described by an interaction . The interaction is a function from the finite sets to self-adjoint observables supported in . The interaction is assumed to be finite range (meaning that if the size of exceeds a certain prescribed size) and translation invariant. These requirements were lifted later.
Although translation invariance is usually assumed, it is not necessary to do so. It is enough to assume that the interaction is bounded above and below on its domain. Thus, the bound is quite robust in the sense that it is tolerant of changes of the Hamiltonian. A finite range is essential, however. An interaction is said to be of finite range if there is a finite number such that for any set with diameter greater than the interaction is zero, i.e., . Again, this requirement was lifted later.
The Hamiltonian of the system with interaction is defined formally by:
The laws of quantum mechanics say that corresponding to every physically observable quantity there is a self-adjoint operator . For every observable with a finite support Hamiltonian defines a continuous one-parameter group of transformations of the observables given by
Here, has a physical meaning of time. (Technically speaking, this time evolution is defined by a power-series expansion that is known to be a norm-convergent series , see, Theorem 7.6.2, which is an adaptation from. More rigorous details can be found in.)
The bound in question was proved in and is the following: For any observables and with finite supports and , respectively, and for any time the following holds for some positive constants and :
where denotes the distance between the sets and . The operator is called the commutator of the operators and , while the symbol denotes the norm, or size, of an operator . It is very important to note that the bound has nothing to do with the state of the quantum system, but depends only on the Hamiltoninan governing the dynamics. Once this operator bound is established it necessarily carries over to any state of the system.
A positive constant depends on the norms of the observables and , the sizes of the supports and , the interaction, the lattice structure and the dimension of the Hilbert space . A positive constant depends on the interaction and the lattice structure only. The number can be chosen at will provided is chosen sufficiently large. In other words, the further out one goes on the light cone, , the sharper the exponential decay rate is. (In later works authors tended to regard as a fixed constant.) The constant is called the group velocity or Lieb-Robinson velocity.
Lieb-Robinson bound shows that for times the norm on the right-hand side is exponentially small. This is the exponentially small error mentioned above.
The reason for considering the commutator on the left-hand side of the Lieb–Robinson bounds is the following:
The commutator between observables and is zero if their supports are disjoint.
The converse is also true: if observable is such that its commutator with any observable supported outside some set is zero, then has a support inside set .
This statement is also approximately true in the following sense: suppose that there exists some such that for some observable and any observable that is supported outside the set . Then there exists an observable with support inside set that approximates an observable , i.e. .
Thus, Lieb-Robinson bounds say that the time evolution of an observable with support in a set is supported (up to exponentially small errors) in a -neighborhood of set , where with being the Lieb-Robinson velocity. Outside this set there is no influence of . In other words, this bounds assert that the speed of propagation of perturbations in quantum spin systems is bounded.
Improvements of the Lieb-Robinson bounds
In Robinson generalized the bound (1) by considering exponentially decaying interactions (that need not be translation invariant), i.e., for which the strength of the interaction decays exponentially with the diameter of the set. This result is discussed in detail in, Chapter 6. No great interest was shown in the Lieb-Robinson bounds until 2004 when Hastings applied them to the Lieb–Schultz–Mattis theorem. Subsequently, Nachtergaele and Sims extended the results of to include models on vertices with a metric and to derive exponential decay of correlations. From 2005–2006 interest in Lieb–Robinson bounds strengthened with additional applications to exponential decay of correlations (see and the sections below). New proofs of the bounds were developed and, in particular, the constant in (1) was improved making it independent of the dimension of the Hilbert space.
Several further improvements of the constant in (1) were made. In 2008 the Lieb-Robinson bound was extended to the case in which each is infinite dimensional. In it was shown that on-site unbounded perturbations do not change the Lieb-Robinson bound. That is, Hamiltonians of the following form can be considered on a finite subset :
where is a self-adjoint operator over , which needs not to be bounded.
Harmonic and Anharmonic Hamiltonians
The Lieb-Robinson bounds were extended to certain continuous quantum systems, that is to a general harmonic Hamiltonian, which, in a finite volume , where are positive integers, takes the form:
where the periodic boundary conditions are imposed and , . Here are canonical basis vectors in .
Anharmonic Hamiltonians with on-site and multiple-site perturbations were considered and the Lieb–Robinson bounds were derived for them, Further generalizations of the harmonic lattice were discussed,
Another generalization of the Lieb–Robinson bounds was made to the irreversible dynamics, in which case the dynamics has a Hamiltonian part and also a dissipative part. The dissipative part is described by terms of Lindblad form, so that the dynamics satisfies the Lindblad-Kossakowski master equation.
Lieb-Robinson bounds for the irreversible dynamics were considered by in the classical context and by for a class of quantum lattice systems with finite-range interactions. Lieb-Robinson bounds for lattice models with a dynamics generated by both Hamiltonian and dissipative interactions with suitably fast decay in space, and that may depend on time, were proved by, where they also proved the existence of the infinite dynamics as a strongly continuous cocycle of unit preserving completely positive maps.
Lieb–Robinson bounds are used in many areas of mathematical physics. Among the main applications of the bound there is the existence of the thermodynamic limit, the exponential decay of correlations and the Lieb–Schultz–Mattis theorem.
Thermodynamic limit of the dynamics
One of the important properties of any model meant to describe properties of bulk matter is the existence of the thermodynamic limit. This says that intrinsic properties of the system should be essentially independent of the size of the system which, in any experimental setup, is finite.
The static thermodynamic limit from the equilibrium point of view was settled much before the Lieb–Robinson bound was proved, see for example. In certain cases one can use a Lieb–Robinson bound to establish the existence of a thermodynamic limit of the dynamics, , for an infinite lattice as the limit of finite lattice dynamics. The limit is usually considered over an increasing sequence of finite subsets , i.e. such that for , there is an inclusion . In order to prove the existence of the infinite dynamics as a strongly continuous, one-parameter group of automorphisms, it was proved that is a Cauchy sequence and consequently is convergent. By elementary considerations, the existence of the thermodynamic limit then follows. A more detailed discussion of the thermodynamic limit can be found in section 6.2.
Robinson was the first to show the existence of the thermodynamic limit for exponentially decaying interactions. Later, Nachtergaele et al. showed the existence of the infinite volume dynamics for almost every type of interaction described in the section "Improvements of Lieb–Robinson bounds" above.
Exponential decay of correlations
Let denote the expectation value of the observable in a state . The correlation function between two observables and is defined as
Lieb–Robinson bounds are used to show that the correlations decay exponentially in distance for a system with an energy gap above a non-degenerate ground state , see. In other words, the inequality
holds for observables and with support in the sets and respectively. Here and are some constants.
Alternatively the state can be taken as a product state, in which case correlations decay exponentially without assuming the energy gap above the ground state.
Such a decay was long known for relativistic dynamics, but only guessed for Newtonian dynamics. The Lieb–Robinson bounds succeed in replacing the relativistic symmetry by local estimates on the Hamiltonian.
Lieb-Schultz-Mattis theorem implies that the ground state of the Heisenberg antiferromagnet on a bipartite lattice with isomorphic sublattices, is non-degenerate, i.e., unique, but the gap can be very small.
For one-dimensional and quasi-one-dimensional systems of even length and with half-integral spin Affleck and Lieb, generalizing the original result by Lieb, Schultz, and Mattis, proved that the gap in the spectrum above the ground state is bounded above by
where is the size of the lattice and is a constant. Many attempts were made to extend this result to higher dimensions, ,
The Lieb–Robinson bound was utilized by Hastings and by Nachtergaele-Sims in a proof of the Lieb–Schultz–Mattis Theorem for higher-dimensional cases. The following bound on the gap was obtained:
Discretisation of the Continuum via Gauss-Quadrature Rules
In 2015, it was shown that the Lieb-Robinson bound can also have applications outside of the context of local Hamiltonians as we now explain. The Spin-Boson model describes the dynamics of a spin coupled to a continuum of oscillators. It has been studied in great detail and explains quantum dissipative effects in a wide range of quantum systems. Let denote the Hamiltonian of the Spin-Boson model with a continuum bosonic bath, and denote the Spin-Boson model who's bath has been discretised to include harmonic oscillators with frequencies chosen according to Gauss Quadrature Rules. For all observables on the Spin Hamiltonian, the error on the expectation value of induced by discretising the Spin-Boson model according to the above discretisation scheme is bounded by
where are positive constants and is the Lieb-Robinson velocity which in this case is directly proportional to , the maximum frequency of the bath in the Spin-Boson model. Here, the number of discrete modes play the role of a distance mentioned below Eq. (1). One can also bound the error induced by local Fock space truncation of the harmonic oscillators
The first experimental observation of the Lieb–Robinson velocity was done by Cheneau et al.
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- M. Cheneau, P. Barmettler, D. Poletti, M. Endres, P. Schauß, T. Fukuhara, C. Gross, I. Bloch, C. Kollath, S. Kuhr, Light-cone-like spreading of correlations in a quantum many-body system, Nature 481, 484–487, (2012) | <urn:uuid:5dde27a7-6228-443d-8f38-058f5bd17dd7> | 3.296875 | 4,273 | Knowledge Article | Science & Tech. | 49.061138 | 95,555,014 |
Mathew YangangPython Web Development Techdegree Student 2,195 Points
i'm trying to return the first 4 and last 4 items from a function using slicing but can't get it correct
def first_4 (item): return item[:4] def first_and_last_4(things): return things[4:4]
Steven Parker131,121 Points
Here's a hint: you might need two slices to do this.
You've already created a function that gets the first four. Now think of how you would write one to get the last four instead. Then combine the two using concatenation. | <urn:uuid:47e44dd0-f6bd-4573-8b32-45f3cbcf20dc> | 2.6875 | 129 | Q&A Forum | Software Dev. | 72.222609 | 95,555,018 |
What makes a pointer point, a sheep dog herd, and a retriever retrieve? Why do Yorkshire terriers live longer than Great Danes? And how can a tiny Chihuahua possibly be related to a Great Dane?
Dogs vary in size, shape, color, coat length and behavior more than any other animal and until now, this variance has largely been unexplained. Now, scientists have developed a method to identify the genetic basis for this diversity that may have far-reaching benefits for dogs and their owners.
In the cover story of tomorrow's edition of the science journal Genetics, research reveals locations in a dog's DNA that contain genes that scientists believe contribute to differences in body and skull shape, weight, fur color and length – and possibly even behavior, trainability and longevity.
"This exciting breakthrough, made possible by working with leaders in canine genetics, is helping us piece together the canine genome puzzle which will ultimately translate into potential benefit for dogs and their owners," said study co-author Paul G. Jones, PhD, a Mars Veterinary™ genetics researcher at the Waltham® Centre for Pet Nutrition – part of Mars® Incorporated, a world leader in pet care that has been studying canine genetic science for the past eight years. "By applying this research approach, we may be able to decipher how genes contribute to physical or behavioral traits that affect many breeds."
Dogs originally derived from the wolf more than 15,000 years ago – a blink of the eye in evolutionary terms. Selective breeding produced dogs with physical and behavioral traits that were well suited to the needs or desires of their human owners, such as herding or hunting ability, coat color and body and skull shape and size. This resulted in the massive variance seen among the more than 350 distinct breeds that make up today's dog population. Until now, the genetic drivers of this diversity have intrigued scientists who have been trying to explain how and why the difference in physical and behavioral traits in dogs changed so rapidly from its wolf origins.
An international team of researchers, which included scientists at the National Human Genome Research Institute, the University of Utah, Sundowners Kennels in Gilroy, California and Mars' Waltham Center for Pet Nutrition in the United Kingdom, studied simple genetic markers known as Single Nucleotide Polymorphisms, or SNPs, to find places in the dog genome that correlate with breed traits. Because many traits are "stereotyped" – or fixed within breeds – researchers can zero in on these "hot spots" to see what specific genes are in the area that might contribute to differences in traits.
The research used 13,000 dog DNA samples provided by Mars Veterinary, which holds one of the most comprehensive canine DNA banks in the world. This collection has been built up with the help of pet owners who have consented to their pets providing cheek swabs and blood samples for the database. Mars' DNA bank allowed the study to cover most of the American Kennel Club recognized breeds that span a wide variety of physical and behavioral traits and differences in longevity.
"With further refinement and additional data, this method could be used to tailor products that may benefit the health of pets," Jones said. "Pet owners and veterinarians may be able to develop better care regimes based on this knowledge. In addition, genetic information about behavioral traits, such as trainability and temperament, could also help veterinarians identify the most lifestyle-appropriate pet for an owner."
This research may also have implications for human health, as dogs suffer from many of the same diseases that we do.
Mars is continuing its commitment to canine genetic science with ongoing investigations to better understand the makeup of a dog's DNA to help benefit the lives of dogs and their owners. The Wisdom Panel MX™ mixed breed analysis test is the first product to use the knowledge gained through this research. Learn more about the Wisdom Panel and this new study at www.wisdompanel.com.
About Mars Veterinary™
Mars Veterinary™ is the one of the newest divisions at MARS® Incorporated, a company known for innovative consumer and pet food brands that are trusted by people around the world.
Mars Veterinary™ is developing sophisticated genetic tests to allow pet owners, veterinarians and care providers to gain insight into the genetic make up of their individual dog. It is reaching new frontiers in canine genomic science, discovering important genetic markers that will help identify breed mixes. These major scientific advances can allow veterinarians and owners to care for dogs with unprecedented wisdom. Through research into pet genetics, Mars Veterinary™ is dedicated to revolutionizing personalized pet care strengthening the bond between people and their canine companions.
About Mars® Incorporated
MARS®, Incorporated, is a privately-held family owned company that produces some of the world's leading confectionery, food, petcare, beverage, and health & nutrition products, and operates in more than 65 countries. Mars, Incorporated employs more than 9,000 associates in the United States and 40,000 associates worldwide with research teams located around the world.
Kate Hartman | EurekAlert!
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
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20.07.2018 | Power and Electrical Engineering
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20.07.2018 | Materials Sciences | <urn:uuid:81e0e0d4-98fa-48c9-a520-38e7a6131673> | 3.625 | 1,614 | Content Listing | Science & Tech. | 35.959681 | 95,555,020 |
Turns out, there's at least one cannibal great white shark hanging around the East Coast.
A Virginia Institute of Marine Science longline fishing survey group caught a four-foot shark on June 8 a few miles off Sandbridge in Virginia Beach, according to the research group's Facebook page.
VIMS researchers were reeling in their 1.2-mile longline that has about 100 baited hooks and is used to study shark populations, when a 13-foot great white decided to make a 4-foot shark on the line its snack.
A Volkswagen Beetle is about the same length as the bigger shark, at roughly 13.5 feet long.
The crew onboard rushed to save the other 40 sharks on their hooks as the great white made a meal of the smaller blacktip shark.
The great white made a mess of the researchers' line and got away before they could get the giant onboard.
On June 7, VIMS caught an 8.5-foot long great white about 6 miles east of First Landing State Park.
Sharks play a key role in marine ecosystems worldwide, VIMS said in its post.
VIMS began studying mid-Atlantic sharks in 1973 with the VIMS Shark Survey, which now stands as the one of the longest-running fishery-independent studies of shark populations in the world. The longline survey brought global attention to significant declines in shark populations due to overfishing, and led to the first U.S. management plan for sharks in 1993, according to VIMS.
As fishing regulations help shark populations rebound in U.S. waters, data from shark research programs at VIMS continue to inform stock assessments and fishery management plans at federal and state levels, according to VIMS.
VIMS tags and releases the sharks it catches on its lines. | <urn:uuid:8e56171a-69b7-43c1-9f34-c6c011b365db> | 2.546875 | 377 | News Article | Science & Tech. | 66.57056 | 95,555,037 |
Divergent natural selection acting on ecological traits, which also affect mate choice, is a key element of ecological speciation theory, but has not previously been demonstrated at the molecular gene level to our knowledge. Here we demonstrate parallel evolution in two cichlid genera under strong divergent selection in a gene that affects both. Strong divergent natural selection fixed opsin proteins with different predicted light absorbance properties at opposite ends of an environmental gradient. By expressing them and measuring absorbance, we show that the reciprocal fixation adapts populations to divergent light environments. The divergent evolution of the visual system coincides with divergence in male breeding coloration, consistent with incipient ecological by-product speciation.
Mendeley saves you time finding and organizing research
Choose a citation style from the tabs below | <urn:uuid:f8554dc2-3ccd-4272-8e32-6742cdc03f3c> | 3.015625 | 161 | Academic Writing | Science & Tech. | 1.076 | 95,555,064 |
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Edited By: E Mateos, JC Guix, A Serra and K Pisciotta
217 pages, Tabs, maps
Brings together results from censuses and inventories of several threatened vertebrate species living in one of the largest and best preserved areas of Atlantic rainforest that have so far escaped from human destruction: the Paranapiacaba forest fragment.
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This is the hydrophobic structure of an Anti-Body. It has been procedurally shaded for a nice organic look. Its ready right out of the box to incorporate into any scientific visualization.
This has been modeled using primarily quads and is 100% accurate to the scientific model.
An antibody, also known as an immunoglobulin, is a large Y-shaped protein used by the immune system to identify and neutralize foreign objects like bacteria and viruses. The antibody recognizes a unique part of the foreign target, termed an antigen.Each tip of the 'Y' of an antibody contains a paratope (a structure analogous to a lock) that is specific for one particular epitope (similarly analogous to a key) on an antigen, allowing these two structures to bind together with precision. Using this binding mechanism, an antibody can tag a microbe or an infected cell for attack by other parts of the immune system, or can neutralize its target directly (for example, by blocking a part of a microbe that is essential for its invasion and survival). The production of antibodies is the main function of the humoral immune system. | <urn:uuid:7014ca7e-2284-410e-97c3-ce5e8ea669c9> | 3.375 | 233 | Knowledge Article | Science & Tech. | 27.682778 | 95,555,070 |
The anterior insular cortex is a small brain region that plays a crucial role in human self-awareness and in related neuropsychiatric disorders. A unique cell type – the von Economo neuron (VEN) – is located there.
Macaque Von Economo Neuron retrogradely labeled in anterior Insula. Picture: Henry Evrard / Max Planck Institute for Biological Cybernetics
For a long time, the VEN was assumed to be unique to humans, great apes, whales and elephants. Henry Evrard, neuroanatomist at the Max Planck Institute for Biological Cybernetics in Tübingen, Germany, now discovered that the VEN occurs also in the insula of macaque monkeys.
The morphology, size and distribution of the monkey VEN suggest that it is at least a primal anatomical homolog of the human VEN. This finding offers new and much-needed opportunities to examine in detail the connections and functions of a cell and brain region that could have a key role in human self-awareness and in mental disorders including autism and specific forms of dementia.
The insular cortex, or simply insula, is a hidden cortical region folded and tucked away deep in the brain – an island within the cortex. Within the last decade, the insula has emerged from darkness as having a key role in diverse functions usually linked to our internal bodily states, to our emotions, to our self-awareness, and to our social interactions. The very anterior part of the insula in particular is where humans consciously sense subjective emotions, such as love, hate, resentment, self-confidence or embarrassment.
In relation to these feelings, the anterior insula is involved in various psychopathologies. Damage of the insula leads to apathy, and to the inability to tell what feelings we or our conversational partner experience. These inabilities and alteration of the insula are also encountered in autism and other highly detrimental neuropsychiatric disorders including the behavioral variant of frontotemporal dementia (bvFTD).
The von Economo neuron (VEN) occurs almost exclusively in the anterior insula and anterior cingulate cortex. Until recently it was believed that the VEN is only present in humans, great apes and some large-brained mammals with complex social behavior such as whales and elephants. In contrast to the typical neighboring pyramidal neuron that is present in all mammals and all brain regions, the VEN has a peculiar spindle shape and is about three times as large. Their numeral density is selectively altered in autism and bvFTD.
Henry Evrard and his team, at the Max Planck Institute for Biological Cybernetics in Tübingen now discovered VENs in the anterior insula in macaque monkeys. His present work provides compelling evidence that monkeys possess at least a primitive form of the human VEN although they do not have the ability to recognize themselves in a mirror, a behavioral hallmark of self-awareness.
“This means, other than previously believed, that highly concentrated VEN populations are not an exclusivity of hominids, but also occurs in other primate species”, explains Henry Evrard. “The VEN phylogeny needs to be reexamined. Most importantly, the very much-needed analysis of the connections and physiology of these specific neurons is now possible.” Knowing the functions of the VEN and its connections to other regions of the brain in monkeys could give us clues on the evolution of the anatomical substrate of self-awareness in humans and may help us in better understanding serious neuropsychiatric disabilities including autism, or even addictions such as to drugs or smoking.Original Publication:
The Max Planck Institute for Biological Cybernetics works in the elucidation of cognitive processes. It employs about 300 people from more than 40 countries and is located at the Max Planck Campus in Tübingen, Germany. The Max Planck Institute for Biological Cybernetics is one of 80 research institutes that the Max Planck Society for the Advancement of Science maintains in Germany and abroad.
Stephanie Bertenbreiter | Max-Planck-Institut
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...
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Washington - An asteroid larger than any skyscraper yet built is hurtling toward Earth, the Daily Mail informs. If it hits on February 4, the paper continues, scientists predict a decade of cold and darkness, and skies choked with soot, and misery across the planet.
Between these paragraphs, the Mail inserts occasional reminders that asteroid 2002 AJ129 will not hit Earth, according to NASA. In fact it is predicted to get no closer than 2.6 million miles from Earth, despite NASA's scary-sounding classification of the rock as "potentially hazardous" - a term which the Mail has paired with horrific illustrations of an asteroid careening straight into the planet.
The Sun is on the story too: "FAST AND DANGEROUS?" Meanwhile, the Daily Star has mocked up a depiction of the asteroid bearing down on Hyde Park. If you loaded up Google on Sunday morning and clicked "News," you'd be greeted by a picture of AJ129 boiling away an ocean, beside the headline, "Doomsday?"
No wonder that on Friday, a concerned citizen sent NASA a link to a report that the asteroid was on a collision course to kill us all, and asked why the agency wasn't talking about it.
"Because it's a lie," NASA tweeted.
Not even a novel lie. AJ129 is one of hundreds of asteroids of a certain size that have flown or will fly within 4.65 million miles of Earth, and are therefore classified by NASA as "potentially hazardous."
None of them are predicted to hit us.
When AJ129 passes closest to Earth next month, NASA has explained, it will still be 10 times farther from us than the moon. And while the headlines are comparing it to the world's tallest building, it could be as big as two-thirds of a mile across, or as small as about 500 yards (about 457 metres).
In any event, it won't matter much to us because it won't hit us.
"We have been tracking this asteroid for over 14 years and know its orbit very accurately," NASA manager Paul Chodas wrote for the agency. "Asteroid 2002 AJ129 has no chance - zero - of colliding with Earth on Feb. 4 or any time over the next 100 years."
So why are the tabloids freaking out about the asteroid? Because they do it all the time.
A few weeks before AJ129 made headlines, the Daily Mail was warning about a truck-sized asteroid "set to make a 'close' approach with Earth in HOURS." It passed by harmlessly.
In December, the paper was worried about 2012 DA14. Last summer it was asteroid NY65, which the Mail wrote "could potentially wipe out life as we know it." It didn't.
Google "potentially hazardous" asteroids, and you get nearly 30 000 results from the Daily Mail alone. Maybe that's because more than 2 000 objects that fit the classification are predicted to swing past Earth in the future, according to NASA's asteroid database. Forget about February 4. There will be one on Monday.
Which isn't to say asteroids are no concern. As The Washington Post has previously written, a relatively small one slammed into Siberia in 1908 with the force of 1 000 atomic bombs. There have been true close calls within the past decade. Even a tiny meteor that burned up in our atmosphere sent an alarming meteoroid arcing across the Michigan sky a few days ago. And if a big asteroid did hit the planet, we really would all probably die.
That very small but very scary possibility is why NASA tracks so many space rocks, and gives one that are predicted to pass within a few moonshots the "potentially hazardous" terminology that births so many headlines.
The agency carried out a simulation with FEMA in 2016 about what could be done if a large asteroid really was found to be on a collision course with Earth. It was a grim exercise, involving the mass evacuation of Los Angeles "while also addressing how to refute rumors and false information that could emerge in the years leading up to the hypothetical impact."
Fortunately, no such asteroid is known to exist.
Unfortunately, NASA's still bogged down with managing rumours.
The Washington Post | <urn:uuid:526462fe-e104-4181-a406-4203d1f4a397> | 2.625 | 861 | News Article | Science & Tech. | 57.747513 | 95,555,087 |
Topic 13.2 Nuclear Physics. 5 hours. Estimating the Radii of Nuclei. Consider an α-particle that is on a direct collision course with a gold nucleus and its subsequent path. Since the gold nucleus is much more massive than the α-particle we can ignore any recoil of the gold nucleus.
where the nucleus with atomic number Z has a charge of Ze and the a-particle has a charge of 2e.
For a gold nucleus (Z = 79) and an α-particle with kinetic energy 4.0 MeV we have that
Positive ions of the element under study are produced in a high voltage discharge tube (not shown) and pass through a slit (S1) in the cathode of the discharge tube. The beam of ions is further collimated by passing through slit S2 which provides an entry to the spectrometer. In the region X, the ions move in crossed electric and magnetic fields.
The electric field is produced by the plates P1and P2and the magnetic field by a coil arrangement. The region X acts as a velocity selector. If the magnitude of the electric field strength in this region is E and that of the magnetic field strength is B (and the magnitude of the charge on an ion is e) only those ions which have a v velocity given the expression Ee = Bev will pass through the slit S3 and so enter the main body, Y, of the instrument.
A uniform magnetic field, B´, exists in region Y and in such a direction as to make the ions describe circular orbits. For a particular ion the radius r of the orbit is given by,
Since all the ions have very nearly the same velocity, ions of different masses will describe orbits of different radii, the variations in value depending only on the mass of the ion.
A number of lines will therefore be obtained on the photographic plate P, each line corresponding to a different isotopic mass of the element. The position of a line on the plate will enable r to be determined and as B´, e and v are known, m can be determined.
IB Outcome 13.2.2
- Students should be able to draw a schematic diagram of the Bainbridge mass spectrometer, but the experimental details are not required.
- Students should appreciate that nuclear mass values provide evidence for the existence of isotopes.
where λ is the constant of proportionality called the decay constant and is defined as ‘the probability of decay of a nucleus per unit time’ and has units of s-1.
NOTE: 1 Bq (Becquerel) = 1 decay / second
an outline of the methods
available for measuring half-
lives and are sufficient for the
actual measurement can be very tricky. For example, many radioactive isotopes decay into isotopes that themselves are radioactive and these in turn decay into other radioactive isotopes. So, although one may start with a sample that contains only one radioactive isotope, some time later the sample could contain several radioactive isotopes.
Tsokos, Page 412
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Scientists have developed a device that can suck water out of desert skies, powered by sunlight alone. They hope that a version of the technology could eventually supply clean drinking water in some of the driest and poorest parts of the globe.
The device is based on a novel material that can pull large amounts of water into its many pores. According to a study published in the journal Science on Thursday, a kilogram of the material can capture several liters of water each day in humidity levels as low as 20 percent, typical of arid regions.
The technology could help address a big and growing problem. A report last year in Science Advances found that four billion people, nearly half in India and China, face “severe water scarcity at least one month of the year.” That means water shortages affect two-thirds of the world’s population. These shortages—and the resulting conflicts—are only expected to become more common in large parts of the world as climate change accelerates.
A team at MIT developed the technology with Omar Yaghi’s laboratory at the University of California, Berkeley. The key component is a promising class of synthetic porous materials called metal-organic frameworks, composed of organic molecules stitched together with metal atoms, which Yaghi pioneered (see “A Better Way to Capture Carbon”). The size and chemical character of the material’s pores can be customized to capture particular types of molecules or allow them to flow through. The material also has a massive surface area, on the order of a football field per gram, enabling it to bond with a large quantity of particles.
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In this case, the scientists employed a previously developed version of the material that Yaghi optimized to efficiently capture water molecules. The prototype bonds with water at night or in shade. But during the day, sunlight hitting the material adds enough energy to convert the water molecules into vapor. In turn, they slip out of the material’s pores and into an adjacent acrylic enclosure. A condenser at the bottom of the vessel collects the water droplets and funnels them into a chamber below, from which clean water can be collected.
The process is completely passive, with no need for solar panels, batteries, or additional energy. Previous water-harvesting technologies have been limited to areas with fog or other high-moisture conditions.
Though they plan to continue refining the technology, they’re “not that far away” from a viable product, says Evelyn Wang, head of MIT’s device research laboratory. She notes that materials of this type are already being mass-produced, at increasingly affordable prices, by the German chemical giant BASF.
Could this technology make a real difference in some of the driest parts of the world?Tell us in the comments.
Yaghi says the technology could be paired with solar panels or other equipment to boost water production for industrial or agricultural purposes. But the big hope, he says, is that these devices could become household fixtures in poorer parts of the world. That would allow families to reliably produce their own water instead of rationing whatever they can carry, or whatever is available, from community wells.
Couldn't make it to EmTech Next to meet experts in AI, Robotics and the Economy?Go behind the scenes and check out our video | <urn:uuid:1a9828c5-9028-40b8-854c-db966cc4aa34> | 3.65625 | 686 | News Article | Science & Tech. | 38.034297 | 95,555,092 |
What is OpenSSL
OpenSSL is a tool used to create a key for mobile apps on Facebook. For anyone who doesn’t use command prompt, like ever, figuring out how to use this tool sucks. So, for my sanity when making my next app, and for anyone else’s sanity who is sick of looking at tutorials from people who don’t know how to give proper detailed directions to people who are learning, I created this tutorial. Please keep in mind, I am using Windows 7, 64 bit, and I am using Unity 5.
Download the current OpenSSL zip file.
Unzip the file. Open up your C: drive. create a folder (directory) named OpenSSL. Open this folder. Paste the contents of the folder you just unzipped into the OpenSSL folder.
Make sure all of your hidden files can be seen. Directions to unhide your files are here.
Now, open the directory .android. On my machine, it looks like this:
See if the debug.keystore file is there. If it is, skip ahead to step 7. If it is not, continue to step 6.
Launch your Android Studio and create a new project. Once the project is created, check to make sure that a debug.keystore file has been created in your .android directory.
Copy the debug.keystore file from your .android folder and paste into your JDK bin Folder. On my machine, it is this:
Open the command prompt. You can find it at Start Menu > All Programs > Accessories > Command Prompt.
Copy the following code and paste it into a text editor like notepad or sticky-notes.
“C:\\Program Files\\Java\\jdk1.7.0_79\\bin\\keytool.exe” -exportcert -alias androiddebugkey -keystore “C:\\Users\\Kendra.android\\debug.keystore” | “C:\\openssl\\bin\\openssl.exe” sha1 -binary | “C:\\openssl\\bin\\openssl.exe” base64
Make sure that you replace my paths, with the paths that you have. Your “jdk1.7.0_79” may be different and your username (where “Kendra” is in the script) is probably different.
Copy your script and paste it into your Command Prompt. You will need to right click and select paste since you cannot use your keyboard shortcuts.
Hit the Enter key on your keyboard.
Your Command Prompt should spit out some letters and numbers on the next line. Now check your Unity 5 project. The error saying that your key should be gone. If it is gone, you are good to go.
If your Unity project is still displaying an error, it is probably something along the line of OpenSSL not found. You will need to add the OpenSSL directory to your path. Continue on.
Go to: Start Menu > Control Panel\\System and Security\\System and select from the left column, Advanced System Settings. Click the Environmental Variables.
Under the System Variables section, scroll down the “Path” and select it. Click the “Edit” button.
Add the path to your OpenSSL bin folder. I added “;C:\\openssl\\bin” to the end of the text line. Do not forget the semicolon before the C. Click the OK button until you are out of Advanced System Settings. (this should be 3 times for you to hit OK)
Restart your Unity and open your project.
Select the Facebook tab > Edit Settings. That error should be gone. If you no longer have errors, you are done. If you still have errors, it probably looks something like key tool not found. Continue on.
You will need to add the JDK (Java Development Kit) bin directory to the Path variable value text line.
Once again, go to Start Menu > Control Panel\\System and Security\\System and select from the left column, Advanced System Settings. Click the Environmental Variables. Under the System Variables section, scroll down the “Path” and select it. Click the “Edit” button.
Add the JDK bin path. I added “;C:\\Program Files\\Java\\jdk1.7.0_79\\bin” to the end of the value text line. Once again, don’t forget the semicolon.
Click the OK button until you are out of Advanced System Settings. (this should be 3 times for you to hit OK). Restart Unity, again, and open your project.
Select the Facebook tab > Edit Settings. That error should be gone. If you no longer have errors, you are done. If you still have errors, post them in the comments and I’ll see what I can do to help you out.
After following these steps, my Facebook developer dilemma was solved. It took me 4 days to figure this crap out. The only thing in my head right now is a stinky pile of poo that I dedicate to Facebook for making it so gosh darn difficult to do that. With all the apps and technology and plugins available, you’d think they could make it a little easier to get the stupid key.
Anyways, hope this helps you out. If you have any questions, post them in the comments. I’ll see what I can do to help you solve your issue. Also, I wrote a lot of this from memory, so if you see a step I may have skipped or it’s not working for you, let me know and I will try to help you out.
- How to Publish Your Game to Google Play Store with Unity
- 12 Steps to Publish Your Android Game
- How to Make a Write-On Effect in After Effects | Adobe Creative Cloud
- SideFX Illume Webinar: Working with Material Style Sheets – Part 2
- Learn How to Work with Shape Tools in Photoshop CC | Adobe Creative Cloud | <urn:uuid:26697e4b-dec2-4251-a9ac-7d4b121780ab> | 2.71875 | 1,283 | Tutorial | Software Dev. | 71.351331 | 95,555,123 |
- Open Access
The effect of heterogeneous crust on earthquakes: a case study of the 2004 Chuetsu, Japan earthquake
© Miyatake; licensee Springer. 2014
Received: 7 August 2013
Accepted: 26 November 2013
Published: 24 April 2014
The cause of asperities (i.e., high-slip regions) remains the subject of much debate in seismology. Several tomography studies have reported previously that high-velocity bodies coincide with asperities. However, it remains unclear whether the heterogeneity of the crust generates these asperities. This can be addressed by conducting stress analysis. The 2004 Chuetsu, Japan earthquake is one of the best examples, since a detailed 3D seismic velocity structure was elucidated. For the resulting structural model, we calculated the heterogeneous stress distribution numerically, adding tectonic loading. Then, we calculated the distribution of the stress drop on the fault based on a frictional coefficient μd, the pore fluid factor λv, and the tectonic loading ratio c. We assumed λv to be 0.85 based on a previous study and calculated the corresponding slip distributions and seismic moment. To have been responsible for this Mw6.6 earthquake, the parameters μd and c must have been located somewhere along a particular line in c - μd space; this constrains the possible range of these parameters. We found that the asperity region for the above slip distribution corresponds approximately to that of the kinematic model, which suggests that the asperity may have been created by heterogeneity in the crustal structure.
The causes of asperities or high-slip areas on faults remain unclear. An asperity was defined originally as the protrusion of a frictional surface in rock mechanics and an asperity model was proposed to explain various types of seismicity along plate boundaries (Kanamori 1981). In this model, asperities are represented as regions of high strength and can accumulate high stress (Das and Kostrov 1983; Lay and Kanamori 1981). Conversely, asperities are often considered to be regions of high slip (e.g., Somerville et al. 1999). In the present study, we adopt the latter definition and omit any discussion of strength. Regardless of the particular meaning preferred, it is generally believed that fault processes (and thus asperities) are controlled by the frictional properties on faults. The inherent variability of fault’s frictional properties has allowed the emergence of a wide variety of fault rupture processes; yet coincidence between asperities and bodies with high seismic velocity has been reported previously for several source regions (Michael and Eberhart-Phillips 1991; Chiarabba and Amato 2003; Kato et al. 2010), suggesting that the stress field itself may cause asperities. However, it remains unclear whether the frictional properties of fault surfaces or stress field characteristics are the primary factors controlling the development of asperities. In the present study, we attempt to address this gap in knowledge by investigating the effects of the stress field on asperities. The 2004 Chuetsu earthquake in Japan and its source region provide an excellent case study in this regard. The highly resolved velocity structure of this earthquake has been inferred from the arrival times of aftershocks, observed by an extremely dense network of temporary seismic stations (Kato et al. 20062009) that detected the presence of a high-velocity body that coincided approximately with an asperity (Kato et al. 2010). For this heterogeneous structural model, we calculate the heterogeneous stress distribution on the fault numerically using the finite difference method (FDM). If the asperity (i.e., high-slip region) can be shown to have been created by the stress field in our stress analysis, it can be considered likely that the asperity was caused by this heterogeneous stress field generated by a heterogeneous crustal structure.
Stress on the fault
where λ and μ represent Lamé constants whose distributions were obtained using a previously developed 3D velocity model (Kato et al. 2006) and from the relationship between P wave velocity and density (Birch 1961), respectively.
In our computation, L x = L y = L z = 50 km. The displacement u0 in Equation 4 may relate to a plate motion. Because the absolute value of the boundary condition (i.e., u0) in Equation 4 was not known, we tentatively assumed , where . Moreover, the resultant stress field had to be adjusted by multiplying with a constant, c ().
We obtained the stress field for c = 1 using the FDM in which grid sizes are taken as 0.4 km for z-axis and 0.3 km for horizontal axes. This ratio corresponded approximately to the dip angle of the fault. We also applied the successive over-relaxation (SOR) iterative method (Press et al. 1992) in our computation.
In system-2, we considered both lithostatic stress and fluid pressure. Thus, σ xx = σ yy = σ zz = σ V = ρgz, where ρ, g, and z are density, gravitational acceleration, and depth, respectively.
It should be noted that the above stress drop is not a true stress drop; rather, it is a potential value based on the assumption that the rupture occurred along the entire region of positive stress drop on the fault. Therefore, this can be considered an approximation of the stress drop that can be used as an initial model for dynamic rupture simulation.
The stress drop distribution described above is controlled by the tectonic loading imposed by the heterogeneity of the crustal structure. To ascertain whether such a stress drop could have generated the mainshock of the 2004 Chuetsu earthquake, we calculated the slip distribution due to the stress drop distribution, described in Equation 7, and compared it with the kinematic model slip distribution (Hikima and Koketsu 2005). Three primary parameters are required (either given or assumed) to calculate the stress drop and estimate the slip distribution according to Equation 7: μd, c, and λv. However, the computation of the slip distribution due to stress drop on a fault in a heterogeneous structure is extremely time-consuming because it requires more than several thousand computations to constrain the parameters.
where Δu L and Δσ L are slip and shear stress drop at fault element L of (ξ i , η j ). L is given by L = i + (j - 1) M, where i = 1,…, M and j = 1,…, N. To reduce computation time, we calculated the slip on the size of the twice longer fault than the kinematic model. For a given shear stress drop distribution Δσ L , we were able to solve the slip distribution Δu L . In this computation, we assumed that , and ρ = 2.8 g/cm3 and used the code of Okada (1992) for computation of Gij. The differences in slip distribution between our method and the heterogeneous model are presented in Appendix B.
As Sibson (2007) estimated λv to be between 0.75 and 0.95 for our study region, we assumed a constant λv of 0.85. Typically, lower values of λv correspond to a requirement for higher loading stress, which corresponds to higher values of c. Through additional computations, we found c to increase by about 30% for a given value of μd when we set λv = 0.8, although the stress drop distribution was found to be very similar to that for λv = 0.85. Thus, it is clear that the value of λv does not affect the overall distribution of the stress drop, although heterogeneity of λv may have some effect on stress distribution. Heterogeneous distributions of λv have not been reported extensively, although Terakawa and Miller (2012) tried to estimate the regional variation in pore fluid pressure in Basel, Switzerland, using Centroid Moment Tensor (CMT) inversion results based on the assumption that tectonic stress is uniform. Both the heterogeneity of fluid pressure and structure are known to be important for earthquake rupture. However, based on the coincidence of the asperity and the zone of high seismic velocity in the present study, the main features of the particular event studied here (e.g., the size and location of the asperity) appear to have been controlled primarily by the heterogeneous seismic velocity structure.
Shibazaki et al. (2008) used finite element analysis to demonstrate that the loading processes of large inland earthquakes in northeastern Japan are determined by the nonuniform thermal structure of the deeper crust and uppermost mantle. However, it has been demonstrated that coincidence between an asperity and high elastic properties (i.e., a high-seismic-velocity structure) cannot always be attributed to rheological properties. An asperity is a region of high moment release, which typically corresponds to large stress drop or high stress; thus, asperities can support strain energy. Therefore, the heterogeneity of elastic properties in the upper crust may create the initial conditions required for a given event, thus controlling the faulting process (i.e., the size and stress drop of asperities). Accordingly, we considered only the elasticity in our stress analysis.
We compared the slip distribution caused by crustal heterogeneity with that indicated by a previously developed kinematic slip model. Our crustal heterogeneity data were inverted using the DD tomography method (Zhang and Thurber 2003) and utilizing a huge dataset of aftershock arrival times observed by the dense seismic network deployed after the mainshock of the 2004 Chuetsu earthquake. Conversely, the kinematic model was inverted from the permanently strong ground motion station. Thus, the small offset (i.e., a few kilometers) between the asperity and the high-velocity body may have resulted from differences in the datasets and modeling parameters used or from differences in inversion method.
We investigated the effects of heterogeneous crustal structure on earthquake rupture, using the 2004 Chuetsu earthquake and its source region as a case study. In particular, we calculated the stress distribution numerically using a 3D crustal structure model of the source region. A region exhibiting a high ratio of shear to normal stress, which can be considered as an indicator of stress drop, was found to coincide approximately to the fault area of the 2004 Chuetsu earthquake. Then, we assumed values for several unknown parameters (frictional coefficient μd, pore fluid factor λv, tectonic loading ratio c) to estimate the potential stress drop distribution. Using the grid search technique, we obtained the relationship between c and μd for the occurrence of an earthquake with a seismic moment of 8.8 × 1018 Nm. Under these conditions, we were able to reproduce the localized rupture area at a location that almost coincides with that of the asperity of the 2004 Chuetsu earthquake, suggesting that the asperity of the mainshock of this earthquake could have been created by a heterogeneous stress field generated from heterogeneous crustal structure. Overall, our results demonstrate that although the dynamic rupture of this asperity is controlled by the frictional properties of the fault surface, the stress field is also an important factor in asperity creation.
The effects of heterogeneous crust on slip distribution
The computations were conducted by the parallel computer of the Earthquake Information Center in the Earthquake Research Institute, University of Tokyo. I thank Dr. K. Hikima and Dr. A. Kato for providing their inversion data. I thank Dr. Shibazaki for valuable comments. I also acknowledge two anonymous reviews for helpful comments.
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This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. | <urn:uuid:8be333ab-69b5-4ef2-a776-ddd625668940> | 2.71875 | 3,598 | Academic Writing | Science & Tech. | 46.693328 | 95,555,134 |
Loss of biodiversity
‘Climate change’ is such an all-encompassing phrase, that it’s easy to forget it will have a multitude of effects, which is why scientists at Imperial College London are looking more deeply at its impact on ecosystems. ‘We are going to have a climate change and we expect alongside that a loss of biodiversity,’ says Dr Pete Manning, who is leading the project along with Dr Sally Power.
At Imperial College’s Silwood Park campus researchers have constructed 168 rain shelters, each one covering a 2.4 m x 2.4 m plot of land. ‘We have a control treatment where the water falls on the roof,’ explains Manning ‘then it drops through holes onto the vegetation below. We have a climate change treatment where the water is gathered up and then we add back a proportion of the water according to a climate scenario, so every day we go out there and we reapply the water.’
A recent report by the Intergovernmental Panel on Climate Change suggests that climate change will mean reduced summer rainfall in the UK, and higher winter rainfall. ‘That’s what we are trying to simulate,’ says Manning. ‘And we are doing that alongside different levels of plant biodiversity to see if certain species go missing from an ecosystem, and whether that makes the ecosystem more vulnerable to climate change.’
Go online now for the full article and pictures on New Conservation in the December Green edition of cubed: www.britishcouncil.org/science-cubed.htm
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Since Henrietta Leavitt's discovery of their unique properties in 1912, the class of bright, pulsating stars known as Cepheids has been used as a distance indicator. Combined with velocity measurements, the properties of Cepheids are also an extremely valuable tool in investigations of how our galaxy, the Milky Way, rotates.
"The motion of Milky Way Cepheids is confusing and has led to disagreement among researchers," says Nardetto. "If the rotation of the Galaxy is taken into account, the Cepheids appear to 'fall' towards the Sun with a mean velocity of about 2 km/s."
A debate has raged for decades as to whether this phenomenon was truly related to the actual motion of the Cepheids and, consequently, to a complicated rotating pattern of our galaxy, or if it was the result of effects within the atmospheres of the Cepheids.
Nardetto and his colleagues observed eight Cepheids with the high precision HARPS spectrograph, attached to the 3.6-m ESO telescope at La Silla, 2400 m up in the mountains of the Chilean Atacama Desert. HARPS, or the High Accuracy Radial Velocity Planetary Searcher, is best known as a very successful planet hunter, but it can also be used to resolve other complicated cases, where its ability to determine radial velocities - the speed with which something is moving towards or away from us - with phenomenally high accuracy is invaluable.
"Our observations show that this apparent motion towards us almost certainly stems from an intrinsic property of Cepheids," says Nardetto.
The astronomers found that the deviations in the measured velocity of Cepheids were linked to the chemical elements in the atmospheres of the Cepheids considered. "This result, if generalised to all Cepheids, implies that the rotation of the Milky Way is simpler than previously thought, and is certainly symmetrical about an axis," concludes Nardetto.Notes
Nicolas Nardetto was at the Max-Planck-Institute for Radio Astronomy, Bonn, Germany, when doing this research.Contact
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The galaxies of the universe grow up kind of like we do. When they’re young, they’re very active, producing new stars out of clouds of dust at a rapid rate. As they age, the churning slows down and eventually stops. No more new stars. The galaxies settle into some relative peace and quiet.
Astronomers have long sought to figure out what exactly leads to this halt in star formation, a phenomenon known as “quenching.” Most simulations show that supermassive black holes, the mysterious objects at the center of most galaxies, must play a major part. The only way the simulations work—the only way astronomers can explain what they see in galaxies through their telescopes—is if black holes somehow contribute to the quenching.
Black holes are not picky eaters. They gobble up any material—cosmic dust or even stars—that wades into their gravitational grasp. When they feed, the material they devour heats up and glows brightly. Scientists give this stage in the life cycle of a black hole the very Star Trek–y name of active galactic nucleus, or AGN. The AGN, scientists believe, releases a bunch of energy, heating up gas in the galaxy and preventing it from cooling enough to condense into individual, brand-new stars. Eventually, this process extinguishes any new star formation.
But scientists haven’t yet nailed down observational evidence for this effect. “There’s a long battle within the community to try to understand the connection between black holes and star formation,” said Ignacio Martín-Navarro, a postdoctoral researcher at the University of California at Santa Cruz.
To investigate that connection, Martín-Navarro and his colleagues recently analyzed massive galaxies and the supermassive black holes that reside in their centers. They found that black holes are indeed responsible for the quenching of galaxies, and that the mass of a black hole influences how quickly that quenching occurs.
Galaxies with more massive black holes became quenched earlier and faster than did galaxies with less massive black holes. The galaxies with bigger black holes experienced more intense rates of star formation in the beginning, during the early universe, than did the ones with smaller black holes. But galaxies with smaller black holes kept producing stars longer, presumably because their black holes weren’t powerful enough to blow away star-making gas and dust. For this reason, galaxies with smaller black holes tend to have a younger population of stars.
The findings were published Monday in a paper in Nature. Martín-Navarro and his team studied the light from a sample of galaxies by splitting it into different wavelengths—a frequently used method in astrophysics that can reveal important properties of astrophysical objects, like the ages of stars. This allowed them to trace the history of star formation in each galaxy, then compare this information with the masses of the black holes at the galaxies’ centers. The mass of a black hole served as a proxy for the amount of energy that gets spewed into the galaxy. The bigger the black hole, the more energy unleashed, the quicker the quenching.
The findings leave some mysteries untouched. Scientists still don’t know how a hungry, feasting black hole spits out star-quenching energy, a process known as feedback. The new research “does seem to give a firm indication of what the effect of black-hole feedback is, even if it doesn’t fill in all the gaps in our knowledge of exactly how the quenching process works,” said Caleb Scharf, the director of the Columbia Astrobiology Center in New York, in an email.
“Bottom line is that the relationship of black-hole mass to galactic stellar populations has been a problem staring us in the face for well over a decade, so any progress toward better quantifying the phenomenon is extremely welcome,” Scharf said.
Martín-Navarro said other research has attempted to find a connection between star formation and the brightness of an AGN, but with little success, perhaps because star formation occurs over longer periods of time than do AGN bursts, which can turn on and off. “It’s really hard to compare things in really different timescales,” Martín-Navarro said.
Although supermassive black holes measure more than 1 million times more massive than the sun, they are practically tiny compared to the galaxies they live in, Martín-Navarro said. Despite their “small” size, black holes influence how galaxies grow and evolve in big ways. It’s as if a single cell in the human body determined the direction of an entire life. That’s what fascinates Martín-Navarro the most—that something so small can dictate the future of something so much bigger.
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Researchers are flying a suite of scientific instruments on two planes from a base of operations in Punta Arenas, Chile: a DC-8 operated by NASA and a Gulfstream V (G-V) operated by the National Science Foundation and the National Center for Atmospheric Research. The G-V will fly through early November. The DC-8, which completed its first science flight Oct. 12, will fly through mid-November.
NASA’s Operation IceBridge mission comprises the largest airborne research campaign ever flown over Earth’s polar region. The mission is designed to continue critical ice sheet measurements in a period between active satellite missions and help scientists understand how much the major ice sheets of Greenland and Antarctica could contribute to sea level rise. Credit: Credit: Michael Studinger/NASA
Ninety-eight percent of Antarctica is covered in ice. Scientists are concerned about how quickly key features are thinning, such as Pine Island Glacier, which rests on bedrock below sea level. Better understanding this type of change is crucial to projecting impacts like sea-level rise.
"With a third year of data-gathering underway, we are starting to build our own record of change," said Michael Studinger, IceBridge project scientist at NASA's Goddard Space Flight Center in Greenbelt, Md. "With IceBridge, our aim is to understand what the world's major ice sheets could contribute to sea-level rise. To understand that you have to record how ice sheets and glaciers are changing over time."
IceBridge science flights put a variety of remote-sensing instruments above Antarctica's land and sea ice, and in some regions, above the ocean floor. The G-V carries one instrument: a laser-ranging topography mapper. The DC-8 carries seven instruments, including a laser altimeter to continue the crucial ice sheet elevation record begun by the Ice, Cloud and land Elevation Satellite (ICESat) mission, which ended in 2009. The flying laboratory also will carry radars that can distinguish how much snow sits on top of sea ice and map the terrain of bedrock below thick ice cover.
While scientists in recent years have produced newer, more detailed data about the ice sheet's surface, the topography of the rocky surface beneath the ice sheet remains unknown in many places. Without knowing the topography of the bedrock, it is impossible to know exactly how much ice sits on top of Antarctica.
A gravimeter aboard the DC-8 will detect subtle differences in gravity to map the ocean floor beneath floating ice shelves. Data on bathymetry, or ocean depth, and ocean circulation from previous IceBridge campaigns are helping explain why some glaciers are changing so quickly.
Flights take off from Punta Arenas and cross the Southern Ocean to reach destinations including West Antarctica, the Antarctic Peninsula and coastal areas. Each lasts 10 to 11 hours.
"We will be re-surveying our previous flight lines to see how much glaciers and ice sheets have changed, and we'll cover new areas to establish a baseline for future years and the ICESat-2 mission in 2016," Studinger said.
Early high-priority DC-8 flights include several flight lines over sea ice near the Antarctic Peninsula, before too much of the ice melts in the southern spring. IceBridge sea ice flights are designed to help scientists understand why sea ice in the Southern Hemisphere is not following the steady decline of sea ice thickness and extent seen in the Arctic.
Other high priority flight lines follow ground traverses being made this year and next, during which NASA scientists will travel different sections of the West Antarctic Ice Sheet, measuring snowfall accumulation and the characteristics of Pine Island Glacier.
Many flight lines will retrace either previous ICESat-1 tracks or future ICESat-2 tracks. Some also will align with current observations made by the European Space Agency's CryoSat-2 satellite. The overlapping flight lines and satellite tracks ultimately will help scientists improve the accuracy of their data.
NASA's Ames Research Center in Moffett Field, Calif., is responsible for IceBridge project management. The DC-8 is based at NASA's Dryden Aircraft Operations Facility in Palmdale, Calif.To follow the mission in more detail, visit:
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Turtle shells are unique in the animal kingdom. In order to be able to breathe in this inflexible casing, tortoises have a muscle sling which is attached to the shell to ventilate the lung.
A team of researchers including paleontologist Torsten Scheyer from the University of Zurich can now reveal that the turtle's ancestor Eunotosaurus africanus already breathed with the aid of such a sling – even though it did not yet have a solid shell. The muscle sling was thus the anatomical prerequisite for the development of the rigid turtle shell.
The present-day extinct ancestors of turtles had a flexible ribcage and breathed, like us, by alternately expanding and contracting the lungs and thorax. The development of a solid shell on the back and belly, however, rendered this kind of respiratory process impossible.
Today’s turtles breathe with the aid of a muscle sling attached to the shell, which contracts and relaxes to aerate the lungs. An international team of researchers from North American, African and European institutes and museums have now discovered the origin of this muscle sling:
in Eunotosaurus africanus, a fossil reptile which lived in South Africa during the Middle Permian around 260 million years ago, as the study just published in Nature Communications reveals.
Instead of a rigid plastron and shell like modern turtles, Eunotosaurus merely had extremely broad, partly overlapping T-shaped ribs. “However, these already heavily restricted the freedom of movement of the ribcage” explains Torsten Scheyer from the Paleontological Institute and Museum of the University of Zurich, who is involved in the study.
Judging by the internal and external bone structures of the ribs, Eunotosaurus evidently only had reduced back muscles, but already possessed a muscle sling that aided respiration. “The small fossil reptile thus provides the explanation as to how the vital adaptation of the breathing apparatus could come about in turtle evolution,” says the UZH paleontologist.
Muscle loop enables shell development
“Eunotosaurus constitutes a morphological link between the body plan of early reptiles and the highly modified body blueprint of the turtles that exist today,” explains Scheyer. The scientists studied the rib plates, so-called costals, of turtle shells and the ribs of various fossil and living vertebrate groups, including mammals, crocodiles and even dinosaurs.
Head of the study Tyler Lyson from the Smithsonian Institution in Washington D.C. and the Denver Museum of Nature and Science, Colorado, adds that, “Based on what we know today, solid shells did not appear in fossil stem turtles until 50 million years after Eunotosaurus.”
The study shows that the steady increase of rigidity of the body wall triggered a separation of the rib and abdominal respiratory muscle functions: The increasing broadening and hardening of the body caused the ribs to become less involved in the respiratory process while the muscles increasingly took over the role. “The ribs became thus free and later completely integrated in the turtle's shell,” says Scheyer.
Lyson, T. R., E. R. Schachner, J. Botha-Brink, T. M. Scheyer, M. Lambertz, G. S. Bever, B. Rubidge, and K. de Queiroz. Origin of the unique ventilatory apparatus of turtles. Nature Communications. November 7, 2014. 5:5211. doi: 10.1038/ncomms6211
Dr. Torsten M. Scheyer
University of Zurich
Paleontological Institute and Museum
Tel.: +41 44 634 23 22
University of Zurich
Tel.: +41 44 634 44 39
Bettina Jakob | Universität Zürich
World’s Largest Study on Allergic Rhinitis Reveals new Risk Genes
17.07.2018 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt
Plant mothers talk to their embryos via the hormone auxin
17.07.2018 | Institute of Science and Technology Austria
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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Particle Physics: A Beginner's Guide - Beginner's Guides (Paperback)Brian R. Martin (author)
- In stock online
Gaining notoriety as the science behind the controversial experiments of the Large Hadron Collider, particle physics explores our most fundamental and mind-blowing problems: How did the Universe start? What are we made of? How small is the smallest thing? Without presuming any prior scientific knowledge, Brian R. Martin takes readers on a wide-ranging tour of the field, from its beginnings in nuclear physics to the discovery of quarks to present-day research into string theory, the mystery of antimatter, and the search for the elusive God particle.
Publisher: Oneworld Publications
Number of pages: 224
Weight: 218 g
Dimensions: 198 x 129 x 12 mm
You may also be interested in...
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University of Guelph researchers have unravelled some of the inner workings of slime produced by one of nature's most bizarre creatures – hagfish.
They've learned how the super-strong and mega-long protein threads secreted by the eel-like animals are organized at the cellular level. Their research was published today in the science journal Nature Communications.
Fig. 2a shows a three-dimensional reconstruction of thread packing within a developing hagfish gland thread cell. Fig. 2b shows a three-dimensional reconstruction of 12 continuous loops of thread within a developing hagfish gland thread cell, revealing the pattern of thread coiling. One loop is highlighted in green. Other objects in the image are mitochondria (red) and nucleus (blue). Fig. 2c shows our three-dimensional model of thread coiling within hagfish gland thread cells based on insights gleaned from Fig. 2b.
Credit: Douglas Fudge
The slime-making process has fascinated and perplexed biologists for more than 100 years, says lead author Prof. Douglas Fudge of Guelph's Department of Integrative Biology.
Besides satisfying scientific curiosity, the discovery also provides valuable insights into the quest to produce synthetic versions of hagfish threads for commercial use.
"What we are doing is biomimicry, imitating and getting inspiration from nature to help solve complex human problems," Fudge said.
"We know that hagfish slime has incredible, interesting properties -- we just don't know how it's achieved. We do know that it's a complex process, and the final product is a super fibre that is almost as strong as spider silk. We need to figure out how the cells make these fibres that are so special."
Hagfishes are an ancient group of bottom-dwelling creatures that have remained relatively unchanged for more than 300 million years. When threatened, they secrete a gelatinous slime containing mucus and tens of thousands of protein threads coiled like skeins of yarn.
The threads are incredibly strong and extremely long, and can uncoil rapidly without tangling. "It's pretty amazing, considering that one of these threads is the equivalent of a rope that is one centimetre in diameter and 1.5 kilometres long," Fudge said.
"How do you coil a rope that long in such a way that it doesn't tangle when it unravels?"
The protein threads could be spun and woven into novel biomaterials, which could provide a sustainable alternative to synthetic fibres such as Nylon, which are made from petroleum feedstocks.
Stretched enough, the protein molecules snap into different arrangements, becoming stronger and tougher, and more akin to spider dragline silks and high performance synthetics like Kevlar, Fudge said. That suggests more applications, including anything from bullet-proof vests to ropes or artificial tendons.
Scientists hope to duplicate the thread-making process, but so far, synthetic versions have proven inferior to natural slime threads.
"If we have any chance of making these things artificially, we have to know how the hagfishes produce these threads inside of their cells," Fudge said.
"We decided to figure out how the thread is organized first, because it may give us clues as to how the cells make it."
Fudge and Guelph researchers Timothy Winegard, Julia Herr and Mark Bernards teamed up with neuro-imaging specialists from universities in California and Michigan. They examined the pattern of slime thread coiling within developing cells using light and electron microscopy and 3D imaging and modelling.
"For the first time, we had the technology to study the morphology and structure of the threads in the cells," Fudge said.
They found that the 15-centimetre-long protein threads are arranged in "skeins" of 15 to 20 conical layers of loops.
Changes in nuclear morphology, size and position explain how the threads are coiled in cells, and the threads change in length and width as cells mature. The next step is to unravel the biochemical and biophysical mechanism behind those changes. "This study provided information about how the thread coils and fills the cells as it grows," Fudge said.
"And these results led us to some very strong clues about how the threads are actually made, and figuring that out is the ultimate goal."
Douglas Fudge | EurekAlert!
Scientists uncover the role of a protein in production & survival of myelin-forming cells
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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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These are large-diameter timber within the Douglas-fir/western hemlock forest of Winder River, Washinton, USA.
Credit score: James Lutz/Utah State College
The highest 1% of the forest has been sharing some important data with researchers. Ninety-eight scientists and 1000’s of area employees have concluded the most important examine undertaken to this point with the Smithsonian Forest World Earth Observatory (ForestGEO), and what they’ve discovered can have profound implications towards ecological theories and carbon storage in forests. Reasonably than inspecting tree species variety in temperate and tropical ecosystems, this world examine emphasised forest construction over an enormous scale. Utilizing giant forest plots from 21 nations and territories, Utah State researchers discovered that, on common, the most important 1% of timber in mature and older forests comprised 50% of forest biomass worldwide. Moreover, the quantity of carbon that forests can sequester relies upon totally on the abundance of massive timber. The dimensions of the most important timber was discovered to be much more essential to forest biomass than excessive densities of small and medium timber. Lead creator Jim Lutz, Assistant Professor at Utah State College mentioned, “Large timber present capabilities that can’t be duplicated by small or medium-sized timber. They supply distinctive habitat, strongly affect the forest round them, and retailer giant quantities of carbon.”
This examine has proven that the construction of the forest is as essential to contemplate as species variety — the most important timber observe their very own algorithm. Utilizing 48 of the big forest dynamics plots from all over the world coordinated by the Smithsonian ForestGEO Program, scientists had been capable of look at the variability of forest construction on a constant foundation. Co-author Dan Johnson, Analysis Affiliate at Utah State College mentioned, “Having a worldwide group of scientists following the identical strategies presents us distinctive alternatives to discover forests at a worldwide scale. This can be a actually great group of scientists united by a ardour for deepening our understanding of forests.”
Tropical forests are well-known to usually have many extra species than temperate forests. Nonetheless, this examine discovered that temperate forests have increased structural complexity, each by way of completely different tree sizes inside an space and in addition between adjoining areas of forest. Co-lead creator Tucker Furniss, PhD pupil at Utah State College mentioned, “The distribution of massive timber has not been effectively defined by idea. Our outcomes emphasize the significance of contemplating these uncommon, however disproportionately essential ecosystem parts. We clearly want extra utilized and theoretical analysis on these essential huge timber.”
The researchers additionally discovered that the most important timber are representatives of the extra frequent tree species. The power of some timber in any given forest to achieve very giant sizes relative to the opposite timber and focus assets appears to be a worldwide phenomenon. “Large timber are particular.” Continued Lutz. “They take a very long time to regrow if they’re eradicated from a forest. Ensuring that we preserve some huge timber in forests can promote and keep all the advantages that forests present to us.”
Supplies supplied by S.J. & Jessie E. Quinney College of Natural Resources, Utah State University. Observe: Content material could also be edited for fashion and size.
- James A. Lutz, Tucker J. Furniss, Daniel J. Johnson, Stuart J. Davies, David Allen, Alfonso Alonso, Kristina J. Anderson-Teixeira, Ana Andrade, Jennifer Baltzer, Kendall M. L. Becker, Erika M. Blomdahl, Norman A. Bourg, Sarayudh Bunyavejchewin, David F. R. P. Burslem, C. Alina Cansler, Ke Cao, Min Cao, Dairon Cárdenas, Li-Wan Chang, Kuo-Jung Chao, Wei-Chun Chao, Jyh-Min Chiang, Chengjin Chu, George B. Chuyong, Keith Clay, Richard Condit, Susan Cordell, Handanakere S. Dattaraja, Alvaro Duque, Corneille E. N. Ewango, Gunter A. Fischer, Christine Fletcher, James A. Freund, Christian Giardina, Sara J. Germain, Gregory S. Gilbert, Zhanqing Hao, Terese Hart, Billy C. H. Hau, Fangliang He, Andrew Hector, Robert W. Howe, Chang-Fu Hsieh, Yue-Hua Hu, Stephen P. Hubbell, Religion M. Inman-Narahari, Akira Itoh, David Janík, Abdul Rahman Kassim, David Kenfack, Lisa Korte, Kamil Král, Andrew J. Larson, YiDe Li, Yiching Lin, Shirong Liu, Shawn Lum, Keping Ma, Jean-Remy Makana, Yadvinder Malhi, Sean M. McMahon, William J. McShea, Hervé R. Memiaghe, Xiangcheng Mi, Michael Morecroft, Paul M. Musili, Jonathan A. Myers, Vojtech Novotny, Alexandre de Oliveira, Perry Ong, David A. Orwig, Rebecca Ostertag, Geoffrey G. Parker, Rajit Patankar, Richard P. Phillips, Glen Reynolds, Lawren Sack, Guo-Zhang M. Music, Sheng-Hsin Su, Raman Sukumar, I-Fang Solar, Hebbalalu S. Suresh, Mark E. Swanson, Sylvester Tan, Duncan W. Thomas, Jill Thompson, Maria Uriarte, Renato Valencia, Alberto Vicentini, Tomáš Vrška, Xugao Wang, George D. Weiblen, Amy Wolf, Shu-Hui Wu, Han Xu, Takuo Yamakura, Sandra Yap, Jess Okay. Zimmerman. World significance of large-diameter timber. World Ecology and Biogeography, 2018; DOI: 10.1111/geb.12747
Cite This Web page:
S.J. & Jessie E. Quinney Faculty of Pure Sources, Utah State College. “Inequality is regular: Dominance of the massive timber.” ScienceDaily. ScienceDaily, eight Might 2018. <www.sciencedaily.com/releases/2018/05/180508155029.htm>.
S.J. & Jessie E. Quinney Faculty of Pure Sources, Utah State College. (2018, Might eight). Inequality is regular: Dominance of the massive timber. ScienceDaily. Retrieved July 13, 2018 from www.sciencedaily.com/releases/2018/05/180508155029.htm
S.J. & Jessie E. Quinney Faculty of Pure Sources, Utah State College. “Inequality is regular: Dominance of the massive timber.” ScienceDaily. www.sciencedaily.com/releases/2018/05/180508155029.htm (accessed July 13, 2018). | <urn:uuid:07a6cc54-b0ee-403d-9337-e686198cfdcb> | 3.359375 | 1,486 | Truncated | Science & Tech. | 42.701528 | 95,555,249 |
Can somebody explain why file1 will be displayed instead of jsp2
If the code below is executed in file1.jsp what will the location bar of the browser display after the execution. <jsp:forward page="file2.jsp" /> You answered: A
A file1.jsp B file2.jsp C file1.jsp_file2.jsp D Code will not compile file1.jsp is displayed. A is true. B would be true when using response.sendRedirect
Post by:Carl Trusiak
What is displayed in a browsers Address or Location Bar is the URL requested from the server. Using jsp:forward, the clients single request is past along to the second resource without telling the browser so, the initial url is displayed. On response.sendRedirect, the clients initial rquest is anwsered with the http header set with the Redirect Response code causing the browser to make a new request for the second URL.
Post by:James Zhai
So,RequestDispatcher.forward() is transparent to the browser, unlike HttpServletResponse.sendRedirect
We find this kind of rampant individuality very disturbing. But not this tiny ad: | <urn:uuid:f92cae4a-4f39-4898-a71c-a4dc3a31719d> | 2.703125 | 258 | Q&A Forum | Software Dev. | 64.990944 | 95,555,255 |
“We see a massive mountain range that kind of reminds me of the Sierra Nevada mountains in the western United States. This mountain range is continuous and is nearly 100 miles long,” said Dr. Bob Brown, team leader of the Cassini visual and infrared mapping spectrometer at the University of Arizona, Tucson.
During an October 25th flyby designed to obtain the highest resolution infrared views of Titan yet, Cassini resolved surface features as small as 400 meters (1,300 feet). The images reveal a large mountain range, dunes, and a deposit of material that resembles a volcanic flow. These data, together with radar data from previous flybys, provide new information on the height and composition of geologic features on Titan.
UK Cassini scientist Professor Michele Dougherty from Imperial College London, said, “What I found most exciting about the infrared observations was the discoveries they revealed on such different scales, from the largest mountain range (nearly 100 miles in length) yet seen on the surface of Titan down to detailed resolution of sand dunes and a volcanic lava flow.”
If Titan were Earth, these mountains would lie south of the equator, somewhere in New Zealand. The range is about 150 kilometers long (93 miles) and 30 kilometers (19 miles) wide and about 1.5 kilometers (nearly a mile) high. Deposits of bright, white material, which may be methane “snow” or exposures of some other organic material, lie at the top of the mountain ridges.
“These mountains are probably as hard as rock, made of icy materials, and are coated with different layers of organics,” said Dr. Larry Soderblom, Cassini interdisciplinary scientist at the U.S. Geological Survey, Flagstaff, Ariz.
He added, “There seem to be layers and layers of various coats of organic ‘paint’ on top of each other on these mountain tops, almost like a painter laying the background on a canvas. Some of this organic gunk falls out of the atmosphere as rain, dust, or smog onto the valley floors and mountain tops, which are coated with dark spots that appear to be brushed, washed, scoured and moved around the surface.”
The mountains probably formed when material welled up from below to fill the gaps opened when tectonic plates pull apart, similar to the way mid-ocean ridges are formed on Earth.
Separately, the radar and infrared data are difficult to interpret, but together they are a powerful combination. In the infrared images, one can see the shadows of the mountains, and in radar, one can see their shape. But when combined, scientists begin to see variations on the mountains, which is essential to unraveling the mysteries of the geologic processes on Titan.
Professor Dougherty adds, “These discoveries show the strength of interdisciplinary science whereby combining data from different instruments onboard Cassini allows us to obtain the best understanding possible of the complex features on this enigmatic moon.”
A fan-shaped feature, possibly a remnant of a volcanic flow, is also visible in the infrared images. The radar instrument imaged this flow and a circular feature from which the flow seems to emanate on a previous flyby, but not in this level of detail.
“The evidence is mounting that this circular feature is a volcano,” said Dr. Rosaly Lopes, Cassini radar team member at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “With radar data alone, we identified it as a possible volcano, but the combination of radar and infrared makes it much clearer.”
Near the wrinkled, mountainous terrain are clouds in Titan’s southern mid latitudes whose source continues to elude scientists. These clouds are probably methane droplets that may form when the atmosphere on Titan cools as it is pushed over the mountains by winds.
The composition of dunes that run across much of Titan is also much clearer. “The dunes seem to consist of sand grains made of organics, built on water-ice bedrock, and there may also be some snow and bright deposits,” Brown said.
Commenting on these new results Professor John Zarnecki from the Open University, Lead Scientist for the Surface Science Package on the European Space Agency’s Huygens probe which descended onto surface of Titan in January 2005, said, "Titan continues to amaze us. It is incredible to think that all those kilometres away there is a moon which contains so many similar geographical features to those found here on Earth. Huygens gave us a panoramic snapshot of the surface of Titan which we continue to anaylse. When coupled with the results from Cassini's flyby's of Titan we are really beginning to build up a detailed picture of the make up of this intriguing moon."
Titan is a complex place and scientists are uncovering the secrets of the surface, one flyby at a time. Scientists hope to get more clues from the next Titan flyby, on December 12th.
For the new infrared images of the mountains visit: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov and http://wwwvims.lpl.arizona.edu .
First evidence on the source of extragalactic particles
13.07.2018 | Technische Universität München
Simpler interferometer can fine tune even the quickest pulses of light
12.07.2018 | University of Rochester
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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Enthalpy change, ΔH, is defined as the heat output of a system as it goes through a reaction under constant pressure. It is an important aspect of thermochemistry, which is the study of energy changes during a chemical or physical reaction . When we calculate enthalpy change, we always assume that the pressure is constant. We are able to calculate enthalpy change numerous ways, notably by the increase in heat, Q, given by an exothermic reaction or the heat absorbed by an endothermic reaction. To do this, we use the concept of calorimetry, the measuring of heat of chemical reactions or physical changes. For this concept, we use a device called a calorimeter, which is a device that creates an isolated system that enables the user to accurately measure the change in temperature, ΔT. We use the following formula in order to calculate Q, quantity of heat, given the mass of the substance, m; its specific heat capacity, c; and the change in temperature, ΔT, given in °C: Q = m · c · Δt
Using this equation, we are able to calculate the heat lost or gained by one of the substances in the reaction. Since heat lost = heat gained in a reaction, we are able to therefore say that the heat lost by the first substance, is equal to the heat gained by the second substance, and therefore: Qsubstance 1 = -Qsubstance 2
Since the law of conservation of energy states that energy cannot be created or destroyed, the change in energy must equal zero and therefore the left side of this equation must be equal in magnitude but opposite in sign of the right side. By substituting equation into equation we are able to derive: m1 · c1 · Δt1 = - (m2 · c2 · Δt2)
and thus we are able to calculate an unknown given the other 5 variables.
The determination of the change in temperature can be done by taking the temperatures in intervals and giving a graphical interpretation of these values. In these experiments, the initial temperature of the substance in question is taken before the second substance is mixed into the calorimeter. Therefore, the determination of the final temperature is slightly more complex. In the perfect case, the final temperature would be able to be calculated immediately after the substances were mixed, and we would be able to form a graph that consists of a straight line with constant slope. In the case of a dissolution, a curve is formed, because the temperature change occurs as the substance is dissolving into the solvent. Therefore, when a plateau has been reached, this is the final temperature.
We can find enthalpy using many different methods. We are able to find the enthalpy of neutralization, a reaction between an acid and a base, by measuring the heat absorbed or produced per mole of a certain substance. Therefore we can use the following equation, where ΔHN is equal to the enthalpy of neutralization; QN is the heat absorbed or produced; and nsub is the number of moles of the substance under consideration: ΔHN = QN / nsub
Furthermore, we can measure the enthalpy of a solution, or of a dissolution, by the of addition the heat absorbed or produced per mole (n) of substance dissolved dissolved by the two substances involved in the reaction. In all cases, a positive enthalpy value results in an endothermic reaction because the solution absorbs energy, and a negative enthalpy value produces an exothermic reaction because the solution loses energy (Waterloo University). Procedure:
The experiment was performed following the procedure outlined in Lab # 3: The Enthalpy of Various Reactions. No modifications were made (CHM 1311 Laboratory Manual , 2013). Observations:
Table 1: Enthalpy of Copper
Mass of metal (g)
Mass of calorimeter (g)
Mass of Lids (g)
Volume of Distilled Water (mL)
Mass H2O and Calorimeter (g)
Initial Temp. of H2O (°C)...
Cited: Parker, V . B ., Thermal Properties of Uni-Univalent Electrolytes, Natl . Stand . Ref . Data Series — Natl . Bur . Stand .(U .S .), No .2, 1965
Randall, Merle, Rossini, Frederick D., The Journal of the American Chemical Society, Vol. 51(2), February 1929, Table VII, pp.334-335.
tutorvista. (2010). Enthalpy of Neutralization. Retrieved Oct 7, 2013, from tutorvista.com: http://www.tutorvista.com/bow/enthalpy-of-neutralisation
Waterloo University. (n.d.). Thermochemistry. Retrieved Oct 7, 2013, from www.science.uwaterloo.ca: http://www.science.uwaterloo.ca/~cchieh/cact/c120/thermosum.html
What in the World Isn 't Chemistry?(2013). General Chemistry. CHM 1311. Laboratory Manual: University of Ottawa.
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J. B. Tatum
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This note covers the following topics: Centres of Mass, Moment of
Inertia, Systems of Particles, Rigid Body Rotation, Collisions, Motion in a
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Damped Oscillatory Motion, Forced Oscillations, Lagrangian Mechanics,
Hydrostatics, The Cycloid, Central Forces and Equivalent Potential, Vibrating Systems and Dimensions. | <urn:uuid:647b6638-a731-4c15-8d8d-ae9538d44a6c> | 2.53125 | 112 | Product Page | Science & Tech. | 6.055 | 95,555,284 |
From: Ocean News Weekly/ By: Ocean Leadership Staff What Passed Many appropriations bills moved last month, including the Senate’s Commerce-Justice-Science bill, which was approved by both the committee and subcommittee. So far, the full appropriations committees have approved all 12 bills in the Senate and 10 in the House. A minibus that includes the [...]
Dr. John Lehrter recently wrapped up research expedition number two of 2018. Both delivering different samples to analyze, but all in a quest to answer the larger question. How does the ocean work? (From Dauphin Island Sea Lab) -- “It’s like being invited to another lab,” Dr. Lehrter said. “ There’s a great deal of [...]
(Credit: Hannah Barkley, Woods Hole Oceanographic Institution) The rising acidity of the oceans threatens coral reefs by making it harder for corals to build their skeletons. A new study identifies the details of how ocean acidification affects coral skeletons, allowing scientists to predict more precisely where corals will be more vulnerable. (From [...]
(Credit: British Antarctic Survey) A new study of tiny marine snails called sea butterflies shows the great lengths these animals go to repair damage caused by ocean acidification. The paper, led by researchers at British Antarctic Survey, is published this month in the journal Nature Communications. (From Phys.org) --The ocean absorbs around one [...]
(Credit: Sophie McCoy/ FSU) California mussels aren't built like they used to be. According to new research, increasing ocean acidification is altering the structural makeup of mussel shells along the West Coast. (From UPI.com/ By Brooks Hays) -- Traditionally, long, cylindrical calcite crystals for neat and predictable rows in the shells of [...]
Melting glaciers might be making ocean water more acidic, an unexpected finding that's given scientists new cause for concern. A new study published yesterday in the journal Nature Climate Change suggests surprising ways that climate change is drastically altering the water chemistry in deep seas—a process that may happen faster than researchers anticipated.
Australian scientists are optimistic that a fertility treatment for coral could help regenerate the Great Barrier Reef. The 2,300 kilometer long coral reef -- a UNESCO World Heritage Site -- has been extensively damaged by a process known as coral bleaching in which warm water stresses the organism and causes it to die.
(Click to enlarge). The Chukchi Ecosystem Observatory is maintained by a multi-institutional, multi-investigator partnership that includes the University of Alaska Fairbanks, the Alaska Ocean Observing System, the North Pacific Research Board, Olgoonik-Fairweather, Université Laval, and the University of Washington. On a recent research mission, University of Alaska Fairbanks scientists brought home the first [...]
The effects of ocean acidification on marine life have only become widely recognized in the past decade. Now researchers are rapidly expanding the scope of investigations into what falling pH means for ocean ecosystems. The ocean is becoming increasingly acidic as climate change accelerates and scientists are ramping up investigations into the impact on marine life and ecosystems. In just a few years, the young field of ocean acidification research has expanded rapidly – progressing from short-term experiments on single species to complex, long-term studies that encompass interactions across interdependent species.
The Senate Oceans Caucus and U.S. Integrated Ocean Observing System Association hosted a briefing on Thursday to address advances in ocean observing and technology that are important to national security, the economy, and environmental health.
Scientists at Caltech and USC have discovered a way to speed up the slow part of the chemical reaction that ultimately helps Earth to safely lock away, or sequester, carbon dioxide into the ocean. Simply adding a common enzyme to the mix, the researchers have found, can make that rate-limiting part of the process go 500 times faster. A paper about the work appears online the week of July 17 ahead of publication in the Proceedings of the National Academy of Sciences.
University of Adelaide researchers have for the first time demonstrated that the ocean acidification expected in the future will reduce fish diversity significantly, with small 'weedy' species dominating marine environments. Published today in Current Biology, the researchers studied species interactions in natural marine environments at underwater volcanic vents, where concentrations of CO2 match those predicted for oceans at the end of the century. They were compared with adjacent marine environments with current CO2 levels. | <urn:uuid:4a5633fa-3fa7-48de-9567-1f2fb2945d46> | 2.84375 | 910 | Content Listing | Science & Tech. | 33.043219 | 95,555,286 |
How radiocarbon dating works
A tree's growth rate changes in a predictable pattern throughout the year in response to seasonal climate changes, resulting in visible growth rings.
" In BAR, we summarized the controversy that has enshrouded this relic, venerated for centuries as the burial cloth of Jesus ("Remains to Be Seen," Strata, Julyl August 1998, p 13).
Check here for important announcements and other Shroud of Turin Website news.
This page will be updated whenever new page additions, articles and other resources are added to the site.
Dendrochronology (or tree-ring dating) is the scientific method of dating tree rings (also called growth rings) to the exact year they were formed in order to analyze atmospheric conditions during different periods in history.
Dendrochronology is useful for determining the timing of events and rates of change in the environment (most prominently climate) and also in works of art and architecture, such as old panel paintings on wood, buildings, etc.
Search for how radiocarbon dating works:
And you can also view every previous year's Website News pages at the links below: The last few months have been exceptionally busy ones. | <urn:uuid:1fd37556-a0cf-4e29-8174-825f388cac51> | 3.6875 | 246 | Knowledge Article | Science & Tech. | 31.457632 | 95,555,288 |
Thermodynamics developed without serious mistake.
- 1798. Thompson, from cannon-boring, realized that work can
be converted in to heat.
- 1824. Carnot idealized a reversible engine as a
cycle between two heat reservoirs -- defined only by their temperature.
- 1842 & 1847. Mayer & Helmholtz reformulated the
conservation of energy, including heat with work.
First Law of Thermo.
- 1843-47. Joule experimentally established equivalence
of work and energy.
- 1848. Kelvin defined absolute scale of temperature, based on
Carnot cycle. (K)
- 1850; 1865. Clausius "gave" thermo laws
It is impossible to construct a device that operates in a cycle and
produces no effect other than the transfer of heat from a
lower-temperature body to a higher-temperature body.
- The energy of the universe is constant.
entropy of the universe ⇒ maximum.
- 1875. Gibbs extended thermodynamics to heterogeneous system
and chemical reactions.
The advent of quantum mechanics lead to statistical mechanics that
linked QM to thermodynamics.
To cite this page:
Development of Thermodynamics
[Monday, 16-Jul-2018 23:36:26 EDT]
Edited by: firstname.lastname@example.org on
Thursday, 03-Sep-2015 14:38:52 EDT | <urn:uuid:2c73fbdf-409f-4219-a424-9a18c766ef7e> | 3.796875 | 308 | Academic Writing | Science & Tech. | 43.975 | 95,555,293 |
The Fenna-Matthews-Olson (FMO) complex is a water-soluble complex and was the first pigment-protein complex (PPC) to be structure analyzed by x-ray spectroscopy. It appears in green sulfur bacteria and mediates the excitation energy transfer from light-harvesting chlorosomes to the membrane-embedded bacterial reaction center (bRC). Its structure is trimeric (C3-symmetry). Each of the three monomers contains eight bacteriochlorophyll a (BChl a) molecules. They are bound to the protein scaffold via ligation of their central magnesium atom either to amino acids of the protein (mostly histidine) or water-bridged oxygen atoms (only one BChl a of each monomer).
Since the structure is available, calculating structure-based optical spectra is possible for comparison with experimental optical spectra. In the simplest case only the excitonic coupling of the BChls is taken into account. More realistic theories consider pigment-protein coupling. An important property is the local transition energy (site energy) of the BChls, different for each, due to their individual local protein environment. The site energies of the BChls determine the direction of the energy flow.
Some structural information on the FMO-RC super complex is available, which was obtained by electron microscopy and linear dichroism spectra measured on FMO trimers and FMO-RC complexes. From these measurements, two orientations of the FMO complex relative to the RC are possible. The orientation with BChl 3 and 4 close to the RC and BChl 1 and 6 (following Fenna and Matthews' original numbering) oriented towards the chlorosomes is useful for efficient energy transfer.
The complex is the simplest PPC appearing in nature and therefore a suitable test object for the development of methods that can be transferred to more complex systems like photosystem I. Engel and co-workers observed that the FMO complex exhibits remarkably long quantum coherence, but after about a decade of debate, Wilkins and Dattani showed that this quantum coherence has no significance to the functioning of the complex. Furthermore, it was shown that the reported long lived oscillations observed in the spectra are solely due to groundstate vibrational dynamics and do not reflect any energy transfer dynamics.
Quantum light harvesting
Light harvesting in photosynthesis employs both classical and quantum mechanical processes with an energy efficiency of almost 100 percent. For light to produce energy in classical processes, photons must reach reaction sites before their energy dissipates in less than one nanosecond. In photosynthetic processes, this is not possible. Because energy can exist in a superposition of states, it can travel all routes within a material at the same time. When a photon finds the correct destination, the superposition collapses, making the energy available. However, no purely quantum process can be wholly responsible, because some quantum processes slow down the movement of quantized objects through networks. Anderson localization prevents the spread of quantum states in random media. Because the state acts like a wave, it is vulnerable to disruptive interference effects. Another issue is the quantum zeno effect, in which an unstable state never changes if it is continuously measured/watched, because watching constantly nudges the state, preventing it from collapsing.
Interactions between quantum states and the environment act like measurements. The classical interaction with the environment changes the wave-like nature of the quantum state just enough to prevent Anderson localisation, while the quantum zeno effect extends the quantum state's lifetime, allowing it to reach the reaction centre. The fact that quantum coherence lasts so long in the FMO influenced many scientists to investigate quantum coherence in the system, with Engel's 2007 paper being cited over 1500 times within 5 years of its publication.
However, in 2015 Wilkins and Dattani computed the numerically exact quantum dynamics of a full 24-site FMO trimer interacting with 24 independent heat baths of dissipative phonons using a Hamiltonian calibrated with Engel's experiments and brought the subject to a close by showing that whether the energy is transferred classically or quantum mechanically, the energy transfer occurs more than 1000 times faster than the energy would be lost to fluorescence.
The problem of finding a reaction centre in a protein matrix is formally equivalent to many problems in computing. Mapping computing problems onto reaction center searches may allow light harvesting to work as a computational device, improving computational speeds at room temperature, yielding 100-1000x efficiency.
- Tronrud, D.E.; Schmid, M.F.; Matthews, B.W. (April 1986). "Structure and X-ray amino acid sequence of a bacteriochlorophyll a protein from Prosthecochloris aestuarii refined at 1.9 A resolution". Journal of Molecular Biology. 188 (3): 443–54. doi:10.1016/0022-2836(86)90167-1. PMID 3735428.
- Fenna, R. E.; Matthews, B. W. (1975). "Chlorophyll arrangement in a bacteriochlorophyll protein from Chlorobium limicola". Nature. 258 (5536): 573–7. Bibcode:1975Natur.258..573F. doi:10.1038/258573a0.
- Vulto, Simone I. E.; Neerken, Sieglinde; Louwe, Robert J. W.; De Baat, Michiel A.; Amesz, Jan; Aartsma, Thijs J. (1998). "Excited-State Structure and Dynamics in FMO Antenna Complexes from Photosynthetic Green Sulfur Bacteria". The Journal of Physical Chemistry B. 102 (51): 10630–5. doi:10.1021/jp983003v.
- Wendling, Markus; Przyjalgowski, Milosz A.; Gülen, Demet; Vulto, Simone I. E.; Aartsma, Thijs J.; Van Grondelle, Rienk van; Van Amerongen, Herbert van (2002). "The quantitative relationship between structure and polarized spectroscopy in the FMO complex of Prosthecochloris aestuarii: refining experiments and simulations". Photosynthesis Research. 71 (1–2): 99–123. doi:10.1023/A:1014947732165. PMID 16228505.
- Pearlstein, Robert M. (1992). "Theory of the optical spectra of the bacteriochlorophyll a antenna protein trimer from Prosthecochloris aestuarii". Photosynthesis Research. 31 (3): 213–226. doi:10.1007/BF00035538. PMID 24408061.
- Renger, Thomas; Marcus, R. A. (2002). "On the relation of protein dynamics and exciton relaxation in pigment–protein complexes: An estimation of the spectral density and a theory for the calculation of optical spectra". The Journal of Chemical Physics. 116 (22): 9997–10019. Bibcode:2002JChPh.116.9997R. doi:10.1063/1.1470200.
- Rémigy, Hervé-W; Stahlberg, Henning; Fotiadis, Dimitrios; Müller, Shirley A; Wolpensinger, Bettina; Engel, Andreas; Hauska, Günter; Tsiotis, Georgios (July 1999). "The reaction center complex from the green sulfur bacterium Chlorobium tepidum: a structural analysis by scanning transmission electron microscopy". Journal of Molecular Biology. 290 (4): 851–8. doi:10.1006/jmbi.1999.2925. PMID 10398586.
- Rémigy, Hervé -W.; Hauska, Günter; Müller, Shirley A.; Tsiotis, Georgios (2002). "The reaction centre from green sulphur bacteria: progress towards structural elucidation". Photosynthesis Research. 71 (1–2): 91–8. doi:10.1023/A:1014963816574. PMID 16228504.
- Adolphs, Julian; Renger, Thomas (October 2006). "How proteins trigger excitation energy transfer in the FMO complex of green sulfur bacteria". Biophysical Journal. 91 (8): 2778–97. Bibcode:2006BpJ....91.2778A. doi:10.1529/biophysj.105.079483. PMC . PMID 16861264.
- Engel, Gregory S.; Calhoun, Tessa R.; Read, Elizabeth L.; Ahn, Tae-Kyu; Mancal, Tomáš; Cheng, Yuan-Chung; Blankenship, Robert E.; Fleming, Graham R. (2007). "Evidence for wavelike energy transfer through quantum coherence in photosynthetic systems". Nature. 446 (7137): 782–786. Bibcode:2007Natur.446..782E. doi:10.1038/nature05678. PMID 17429397.
- Wilkins, David M.; Dattani, Nikesh S. (2015). "Why Quantum Coherence Is Not Important in the Fenna–Matthews–Olsen Complex". Journal of Chemical Theory and Computation. 11 (7): 3411–3419. arXiv: . doi:10.1021/ct501066k.
- R. Tempelaar; T. L. C. Jansen; J. Knoester (2014). "Vibrational Beatings Conceal Evidence of Electronic Coherence in the FMO Light-Harvesting Complex". J. Phys. Chem. B. 118 (45): 12865–12872. doi:10.1021/jp510074q.
- MIT (2013-11-25). "Quantum Light Harvesting Hints at Entirely New Form of Computing". Technologyreview.com. Retrieved 2013-12-06.
- Vattay, Gabor; Kauffman, Stuart A. (2013). "Evolutionary Design in Biological Quantum Computing". arXiv: [cond-mat.dis-nn]. | <urn:uuid:f129515e-547d-409c-a990-8d5c19c0ace5> | 2.640625 | 2,174 | Knowledge Article | Science & Tech. | 55.530717 | 95,555,309 |
Weather: How It Works and Why It MattersOnline Periodical or Article
Scientists have delved deep into the smallest particles of matter and have extended their view to the far reaches of the universe, but still they are unable to predict the temperature five days hence. In this intriguing book, two experts in meteorology and astronomy take us on a grand tour of Earth's weather. Amid colorful anecdotes of the Galápagos, Siberia, and places closer to home, they describe the factors involved in shaping our weather, from humidity and prevailing winds to air-pressure systems and the causes of seasonal change. They also explore the history of Earth's climate and its pivotal role in the development of life and human evolution. The authors end with a discussion of the major threats to Earth's atmosphere brought on by human activity, including global warming and ozone depletion, and argue that pure science-not politics-should dictate our policy responses.
Publisher: Perseus Books Group | <urn:uuid:cde01dcc-376c-4bfa-8b8e-75e914e3aa8f> | 3.375 | 191 | Content Listing | Science & Tech. | 23.230663 | 95,555,324 |
The Indian monsoon is a complex system which is likely to change under global warming. While it is in the very nature of weather to vary, the question is how much and whether we can deal with it. Extreme rainfall, for example, bears the risk of flooding, and crop failure.
Computer simulations with a comprehensive set of 20 state-of-the-art climate models now consistently show that Indian monsoon daily variability might increase, according to a study published by the Potsdam Institute for Climate Impact Research (PIK).
“Increased variability – this rather technical term translates into potentially severe impacts on people who cannot afford additional loss,” says Anders Levermann, one of the study’s authors and co-chair of PIK’s research domain Sustainable Solutions. “The fact that all these different models agree is a clear message that adaptation measures can be built on.”
Jonas Viering | PIK Potsdam
Global study of world's beaches shows threat to protected areas
19.07.2018 | NASA/Goddard Space Flight Center
NSF-supported researchers to present new results on hurricanes and other extreme events
19.07.2018 | National Science 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
20.07.2018 | Materials Sciences | <urn:uuid:18fcaa5c-0a62-4b91-ac3e-9938b6a7e4d7> | 3.234375 | 766 | Content Listing | Science & Tech. | 38.614307 | 95,555,350 |
|کد مقاله||کد نشریه||سال انتشار||مقاله انگلیسی||ترجمه فارسی||نسخه تمام متن|
|5744810||1412371||2017||4 صفحه PDF||سفارش دهید||دانلود کنید|
The understanding that biodiversity is supported by an entangled network of interactions is fundamental if we are to guarantee the persistence of endemic and restricted-range taxa. When it comes to remote, isolated and rural areas, local human communities play a pivotal role in preserving their native flora and fauna. Locals typically show contrasting aesthetic appreciation for different species, unaware that the fate of highly valued species might be closely linked to the activity of non-charismatic and disregarded species. Therefore, conveying the importance of biotic interactions in sustaining biodiversity is important to incentivise environmental awareness in those areas. The remote Socotra Archipelago (Yemen), a Natural World Heritage, hosts one of the oldest forest ecosystems on Earth and 31 endemic reptile species. The relic dragon's blood tree Dracaena cinnabari is classified as Vulnerable and it is highly valued among locals. On the contrary, reptiles are typically persecuted and feared by them, in spite of the fact that they might provide services to D. cinnabari. In order to document the role of nocturnal lizards as pollinators of D. cinnabari, we conducted a trip to Socotra Island and we examined 11 tree populations at night for the presence of reptiles and whether they carry pollen in their snouts. Our results confirmed that three species of geckos carried pollen grains of D. cinnabari and at least seven other unidentified species. This result indicates that these geckos visit D. cinnabari flowers, likely to feed upon pollen or nectar, suggesting that they may pollinate this relic tree. We point out that by focusing on the need of preserving mutualistic biotic interactions, instead of individual species, environmental awareness would increase and Socotri people would steadily shift their attitude towards an holistic preservation of D. cinnabari.
Journal: Journal for Nature Conservation - Volume 35, February 2017, Pages 20-23 | <urn:uuid:566eeb24-0c15-47a5-b7fd-2c5aa05efeb1> | 3.15625 | 522 | Academic Writing | Science & Tech. | 31.855351 | 95,555,369 |
Potentially life-giving water still flows across the ancient surface of Mars from time to time, NASA scientists said Monday in revealing a potential breakthrough in both the search for life beyond Earth and human hopes to one day travel there.
While the discovery doesn't by itself offer evidence of life on Mars, either past or present, it does boost hopes that the harsh landscape still offers some refuge for microbes to cling to existence.
"The existence of liquid water, even if it is super salty briny water, gives the possibility that if there's life on Mars, that we have a way to describe how it might survive," said John Grunsfeld, associate administrator for the Science Mission Directorate at NASA.
NASA researchers using an imager aboard the Mars Reconnaissance Orbiter confirmed the watery flows by looking at light waves returned from seasonal dark streaks on the surface, long suspected to be associated with liquid water.
The investigation showed the streaks absorb light at specific wavelengths associated with chemicals known to pull water from the Martian atmosphere in a process known as deliquescence, said Georgia Tech doctoral student Lujendra Ojha, who first discovered the streaks while still an undergraduate student at the University of Arizona in 2011.
The chemicals allow the water to remain liquid at lower temperatures but also help keep it from boiling off in the thin atmosphere of Mars, the researchers said.
It remains unclear where the water comes from. Theories include deliquescence, melting subsurface ice or even a liquid-water aquifer that feeds the process. Discovering what precisely is causing the phenomenon is a mystery for the next round of investigations, said Michael Meyer, lead scientist for NASA's Mars Exploration Program.
The researchers' findings are in a new paper being presented this week at the European Planetary Science Congress in France.
This is not the first discovery of water on Mars.
Researchers have known for many years that Mars has water frozen at its poles, in its thin atmosphere, and, most recently, in tiny puddles that appear to form at night on the surface.
Nor is it the first potential clue that Mars could have once -- or may still -- host life. The Mars Curiosity rover, for instance, has detected methane on the surface of Mars, as well as other chemical signatures suggesting the possibility of past or present life.
It remains to be seen whether the new discovery improves the odds of life on Mars, but researcher Mary Beth Wilhelm said the results suggest "more habitable conditions on the near surface of Mars than previously thought."
How habitable, she said, depends on how salty and how cold the conditions are.
But Alfred McEwen, who heads up NASA's HiRISE high-resolution camera aboard the Mars orbiter, said he's fairly confident life will one day be found on Mars.
"It's very likely, I think, that there's life somewhere in the crust of Mars, microbes," he said.
Jim Green, director of planetary science at NASA, said the discovery announced Monday puts NASA in a perfect position to look for that life.
"We haven't been able to answer the question, 'Does life exist beyond Earth?' " Green said. "But following the water is a critical element of that. We now have, I think, a great opportunity to be in the right locations on Mars to thoroughly investigate that." | <urn:uuid:c6d3b8ec-43df-440a-8df8-1235f6f19b1f> | 3.84375 | 682 | News Article | Science & Tech. | 38.395435 | 95,555,378 |
Chemistry is the scientific discipline involved with compounds composed of atoms, i.e. elements, and molecules, i.e. combinations of atoms: their composition, structure, properties, behavior and the changes they undergo during a reaction with other compounds. Chemistry addresses topics such as how atoms and molecules interact via chemical bonds to form new chemical compounds. There are four types of chemical bonds: covalent bonds, in which compounds share one or more electron(s); ionic bonds, in which a compound donates one or more electrons to another compound to produce ions (cations and anions); hydrogen bonds; and Van der Waals force bonds.
In the scope of its subject, chemistry occupies an intermediate position between physics and biology. It is sometimes called the central science because it provides a foundation for understanding both basic and applied scientific disciplines at a fundamental level. Examples include plant chemistry (botany), the formation of igneous rocks (geology), how atmospheric ozone is formed and how environmental pollutants are degraded (ecology), the properties of the soil on the moon (astrophysics), how medications work (pharmacology), and how to collect DNA evidence at a crime scene (forensics).
The history of chemistry spans a period from very old times to the present. Since several millennia BC, civilizations were using technologies that would eventually form the basis of the various branches of chemistry. Examples include extracting metals from ores, making pottery and glazes, fermenting beer and wine, extracting chemicals from plants for medicine and perfume, rendering fat into soap, making glass, and making alloys like bronze. Chemistry was preceded by its protoscience, alchemy, which is an intuitive but non-scientific approach to understanding the constituents of matter and their interactions. It was unsuccessful in explaining the nature of matter and its transformations, but, by performing experiments and recording the results, alchemists set the stage for modern chemistry. Chemistry as a body of knowledge distinct from alchemy began to emerge when a clear differentiation was made between them by Robert Boyle in his work The Sceptical Chymist (1661). While both alchemy and chemistry are concerned with matter and its transformations, the crucial difference was given by the scientific method that chemists employed in their work. Chemistry is considered to have become an established science with the work of Antoine Lavoisier, who developed a law of conservation of mass that demanded careful measurement and quantitative observations of chemical phenomena. The history of chemistry is intertwined with the history of thermodynamics, especially through the work of Willard Gibbs.
The word chemistry comes from alchemy, which referred to an earlier set of practices that encompassed elements of chemistry, metallurgy, philosophy, astrology, astronomy, mysticism and medicine. It is often seen as linked to the quest to turn lead or another common starting material into gold, though in ancient times the study encompassed many of the questions of modern chemistry being defined as the study of the composition of waters, movement, growth, embodying, disembodying, drawing the spirits from bodies and bonding the spirits within bodies by the early 4th century Greek-Egyptian alchemist Zosimos. An alchemist was called a 'chemist' in popular speech, and later the suffix "-ry" was added to this to describe the art of the chemist as "chemistry".
The modern word alchemy in turn is derived from the Arabic word al-kīmīā (الكیمیاء). In origin, the term is borrowed from the Greek χημία or χημεία. This may have Egyptian origins since al-kīmīā is derived from the Greek χημία, which is in turn derived from the word Kemet, which is the ancient name of Egypt in the Egyptian language. Alternately, al-kīmīā may derive from χημεία, meaning "cast together".
The current model of atomic structure is the quantum mechanical model. Traditional chemistry starts with the study of elementary particles, atoms, molecules, substances, metals, crystals and other aggregates of matter. This matter can be studied in solid, liquid, or gas states, in isolation or in combination. The interactions, reactions and transformations that are studied in chemistry are usually the result of interactions between atoms, leading to rearrangements of the chemical bonds which hold atoms together. Such behaviors are studied in a chemistry laboratory.
The chemistry laboratory stereotypically uses various forms of laboratory glassware. However glassware is not central to chemistry, and a great deal of experimental (as well as applied/industrial) chemistry is done without it. | <urn:uuid:124d29ee-b9fe-4179-b206-6b34ac998fa3> | 3.6875 | 964 | Knowledge Article | Science & Tech. | 25.124545 | 95,555,390 |
- Research news
- Open Access
Sequence of the color purple
© BioMed Central Ltd 2003
Published: 9 September 2003
Sequencing the genomes of organisms can give insights into potential gene products and regulatory mechanisms that may yield biotechnological products. The free-living, gram-negative bacterium Chromobacterium violaceum - native to tropical and subtropical aquatic environments - produces compounds of known biotechnological importance. One of these is the violet pigment violacein, produced in response to quorum sensing (the ability of bacteria to coordinate gene expression in a bacteria density - dependent manner), but the potential of this organism has been incompletely explored. Ana Tereza Ribeiro de Vasconcelos at the Laboratorio Nacional de Computacao Cientifica in Brazil, together with over a hundred members of the Brazilian National Genome Project Consortium - comprising 29 sequencing and bioinformatics centers - report the full genome sequence of C. violaceum in the September 8 early edition of Proceedings of the National Academy of Sciences USA (Proc Natl Acad Sci USA 2003, DOI:10.1073/pnas.1832124100).
The consortium sequenced C. violaceum strain ATCC 12472 using cosmid libraries in Lawrist 4 and pUC18 and annotated the sequence using their own software that automatically identified genome landmarks before assigning putative functions using BLAST searches and a variety of programs for identification of protein sequences. The genome consists of a single circular chromosome 4.8 Kb in length and has a G+C content of approximately 65%. The authors identified 4431 uniformly distributed open reading frames (ORFs) having an average length of 954 bp, of which 2717 encode proteins of known function. Comparison with other organisms showed that 17.4% of the ORFs show similarity to those in Ralstonia solanaceraeum - a soil-borne pathogen - and that the majority of these encode gene products closely associated with a soil-dwelling lifestyle (e.g., cell motility and inorganic ion transport).
The authors also showed that the bacterium can metabolize both aerobically and anaerobically and revealed information on its ability to adapt to changing environments, on the widespread use of quorum sensing to regulate gene expression, and on the basis for its occasional human pathogenicity, as well as on novel proteins induced in response to a variety of environmental chemical stresses.
The sequencing of more, similar, free-living tropical bacteria could lead to "the production of industrially useful genes, enzymes, and secondary metabolites [that] would [not only] benefit... the biotechnological and pharmaceutical industries in the developing world, where most tropical diversity is located, but would also provide a further stimulus to the preservation of the precious ecosystems where these organisms are found," the authors conclude. | <urn:uuid:627402a2-9349-4245-85ea-88e66d02d9a2> | 3.203125 | 595 | Academic Writing | Science & Tech. | 17.442183 | 95,555,402 |
Solar storms, space junk and the formation of the Universe are about to be seen in an entirely new way with the start of operations today by the $51 million Murchison Widefield Array (MWA) radio telescope.
The first of three international precursors to the $2 billion Square Kilometre Array (SKA) telescope, the MWA is located in a remote pocket of outback Western Australia. It is the result of an international project led by Curtin University and was officially turned on by Australia’s Science and Research Minister, Senator Kim Carr.
AARNet and CSIRO have collaborated to deliver a transmission network for the MWA. The network is installed on fibre optic infrastructure constructed by AARNet for the CSIRO and by Nextgen Networks for the federal government-funded Regional Backbone Blackspots Program.
Using bleeding edge technology, the MWA will become an eye on the sky, acting as an early warning system that will potentially help to save billions of dollars as it steps up observations of the Sun to detect and monitor massive solar storms. It will also investigate a unique concept which will see stray FM radio signals used to track dangerous space debris.
The detailed observations will be used by scientists to hunt for explosive and variable objects in the Milky Way such as black holes and exploding stars, as well as to create the most comprehensive survey of the Southern Hemisphere sky at low radio frequencies.
From today, regular data will be captured through the entirely static telescope which spans a three kilometre area at the CSIRO’s Murchison Radio-astronomy Observatory, future home to the SKA.
AARNet is providing the network services for the transmission of the data between the MWA sensors and the Pawsey High Performance Computing Centre for SKA Science, located 800kms away in Perth.
John Nicholls, AARNet’s Infrastructure Development Manager said “AARNet is providing a network that’s scalable to support the needs of the MWA now and into future early phases of the SKA”.
Jul 16, 2018
Jun 29, 2018
May 15, 2018 | <urn:uuid:83f74f05-58fa-41f6-a293-1f006077a09f> | 2.875 | 439 | News (Org.) | Science & Tech. | 29.900508 | 95,555,424 |
Is the world running out of wilderness?
Every single corner of the globe is losing wilderness — over 10 per cent has disappeared in 20 years
If you don't have weekend plans yet, you may want to consider running into the wilderness.
According to a new study published in Current Biology, every single corner of the globe is experiencing a shocking loss of wilderness — over 10 per cent in only 20 years.
How much wilderness has the world lost?
The measured amount is 3.3 million square kilometres — about the size of two Alaskas. In Canadian terms, that's almost 600 Prince Edward Islands or five Albertas.
Researchers from the University of Northern British Columbia say most of the global wilderness loss is in South America around the Amazon, and in Africa where human encroachment for pasture lands and resource extraction is at an all time high.
The scale of loss in those areas is staggering. Up to 30 per cent of wilderness in the Amazon basin has disappeared in the past two decades.
And Canada is not immune. According to researchers, we've lost wilderness areas all across the country — much of it in the North, but also basically anywhere in Canada with vast expanses of forest and wildlife.
Why is wilderness so important?
The senior author of the study, Oscar Venter, said the value of wild spaces is hard to overstate. In areas where human development has encroached on biologically rich landscapes, wildlife is often put in serious peril.
"They really represent the last refuge for many of the world's endangered species," said Venter, "really the last places that they're holding on is in the wilderness."
Humans rely on wilderness, too, and not just for its inherent environmental and economic value.
"[Wilderness is] really the last home and livelihood for many of the world's most economically and politically marginalized people. A lot of the world's Indigenous cultures live in or use wilderness areas in often traditional ways."
What's the difference between wilderness protection and habitat protection?
When it comes to endangered species and discussions of habitat destruction, we often focus on either very unique habitats or biodiversity hotspots. But just because an area is wild doesn't mean something is officially endangered there, or that it is particularly biodiverse.
Take, for instance, the permafrost in Canada's North. It's not exactly bursting at the seams with dense wildlife or even endangered species, but the vast expanses of tundra in Canada are crucial to mitigating climate change.
Permafrost acts as a huge carbon sink. If it's destroyed or removed because of human encroachment, massive amounts of carbon are liberated into the atmosphere.
How did the researchers measure the area of wilderness lost?
It wasn't easy. Researchers first had to define what they meant by wilderness: areas free of any human disturbance, basically an untouched ecosystem. In Canada, think areas like the heart of the Rocky Mountains or the Arctic tundra. That means no roads, few people per square kilometre and no cities, agriculture or pastures nearby.
Researchers then compared their measurements from 17 years ago to today. Essentially, they considered the entire Earth wilderness asked the question: how much human encroachment is there?
The answer: just 23 per cent of the entire surface of the Earth is considered true wilderness, compared to 33 per cent one generation ago.
What does this mean for conservation efforts?
For one thing, it suggests our conservation efforts to date haven't really worked. The research indicates we should maybe focus on a broader picture of what should be protected.
The problem is that protecting "wilderness" is a tough sell. It's much easier to say, 'don't cut this part of the forest down because an adorable cuddly panda lives there'.
At this point, there is no major global agreement or policy in place that protects wilderness over discrete ecosystems or areas. We have to realize that when an ecosystem is gone, it's gone. It is easier to restore an endangered animal from a captive population than to replace an ecosystem that took a millennium to build and balance.
The amount of wilderness we've lost — 10 per cent in 17 years — is staggering. If this pace keeps up, we'll be without pristine ecosystems in a decade.
But if there's one hopeful thing that this study does say, it's that it's not too late — there's still time to protect the planet in a way that will truly have a lasting impact. | <urn:uuid:ea56082d-bbf4-43c9-b2e3-fb8010bb0c7d> | 3.515625 | 913 | News Article | Science & Tech. | 46.760265 | 95,555,436 |
Competition of Neutron Capture and Beta Decay at the 85Kr and 151Sm Branchings, a Means to Estimate the s-Process Pulse Conditions
s-process abundances of heavy elements are successfully reproduced using an exponential distribution of neutron exposures [1,2]. This behavior has been explained as the result of a pulsed irradiation of s-process seed material in the He-shell of red giant stars . A possibility to ascertain the pulsed nature of the s-process is offered by the analysis of branchings in the synthesis path. A branching is the result of a competition between neutron capture and beta decay of a radioactive isotope situated on the path. The pulsed nature of the s-process can show up due to the interpulse decay of the radioactive branch point nucleus and the necessary reformation of its abundance during the next pulse.
KeywordsNeutron Capture Beta Decay Capture Cross Section Pulse Condition Pulse Nature
- 2.H. Beer: 5th Moriond Astrophysics Meeting, Nucleosynthesis and its Implications on Nuclear and Particle Physics, Les Arcs, Savoie, March 17–23, 1985, eds. J. Audouze, N. Mathieu (D. Reidel Publishing Company 1986) p. 263Google Scholar
- 5.H. Beer: 2nd IAP Rencontre on Nuclear Astrophysics, Paris July 7–11, 1986Google Scholar | <urn:uuid:65c2a3e2-7abd-46a4-beeb-7f6a0788b6d6> | 2.640625 | 295 | Academic Writing | Science & Tech. | 48.755924 | 95,555,439 |
A limitation in using hydrogen as a fuel in hydrogen-powered vehicles is the difficulty involved in storing it in a cost-effective and convenient manner. While it is possible to store hydrogen using metals, the resulting products often can be prohibitively expensive and cause environmental problems.
Chemists at UC Riverside now offer a possible solution. A class of carbenes – molecules that have unusual, highly reactive carbon atoms – can mimic, to some extent, the behavior of metals, the chemists have found. Called cyclic alkyl amino carbenes or CAACs, these organic molecules, the researchers report, could be used to develop carbon-based systems for storing hydrogen.
Study results appear in the April 20 issue of Science.
In their experiments, the researchers found that the CAACs can split hydrogen under extremely mild conditions, a behavior that has long been seen in metals reacting with hydrogen.
"The mode of action of these organic molecules, however, is totally different from that of metals," said Guy Bertrand, a distinguished professor of chemistry who led the research. "Moreover, the CAACs are able to split ammonia as well – an extremely difficult task for metals."
Bertrand explained that such a splitting of ammonia, under certain conditions, can pave the way for transforming abundant and inexpensive ammonia into useful amino compounds used to make pharmaceuticals and bulk industrial materials. "This is one of the top challenges for the 21st century," he said.
According to the UCR research team, the metal-mimicking carbenes offer another low-cost and low-toxicity benefit: Scientists now may be able to use non-metallic catalysts for a reaction, called "hydrogenation reaction," which plays a critical role in the food, petrochemical and pharmaceutical industries.
In their study, the researchers exposed a solution of CAACs to both gaseous hydrogen and liquid ammonia. "We used nuclear magnetic resonance spectroscopy to analyze the products," said Guido Frey, the first author of the research paper and a postdoctoral fellow, supported by the Alexander von Humboldt Foundation, in Bertrand’s lab. "And we used single crystal X-ray diffraction analysis to confirm the structure of the products."
A carbene is a molecule that has a carbon atom with six electrons instead of the usual eight. Because of the electron deficiency, carbenes are highly reactive and usually unstable in nature.
Iqbal Pittalwala | EurekAlert!
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....
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Microplastic Transfers Toxic Levels of Chemicals
News Dec 04, 2013
However, until now researchers haven't known whether ingested plastic transfers chemical additives or pollutants to wildlife.
A new study conducted by UC Santa Barbara's National Center for Ecological Analysis and Synthesis (NCEAS) shows that toxic concentrations of pollutants and additives enter the tissue of animals that have eaten microplastic. The findings are published today in Current Biology.
Lead author Mark Anthony Browne, a postdoctoral fellow at NCEAS, had two objectives when the study commenced: to look at whether chemicals from microplastic move into the tissues of organisms; and to determine any impacts on the health and the functions that sustain biodiversity. Microplastics are micrometer-size pieces that have eroded from larger plastic fragments, from fibers from washing clothing or from granules of plastic added to cleaning products. Microplastics are then consumed by a variety of animals, beginning with the bottom of the food chain. These tiny bits of plastic act like magnets, attracting pollutants out of the environment to attach to the plastic.
"The work is important because current policy in the United States and abroad considers microplastic as non-hazardous," Browne said. "Yet our work shows that large accumulations of microplastic have the potential to impact the structure and functioning of marine ecosystems."
Browne ran laboratory experiments with colleagues in the United Kingdom in which they exposed lugworms (Arenicola marina) to sand with 5 percent microplastic (polyvinylchloride) that also contained common chemical pollutants (nonylphenol, phenanthrene) and additives (triclosan, PBDE-47). Results showed that pollutants and additives from ingested microplastic were present in the worms' tissues at concentrations that compromise key functions that normally sustain health and biodiversity.
"In our study, additives, such as triclosan (an antimicrobial), that are incorporated into plastics during manufacture caused mortality and diminished the ability of the lugworms to engineer sediments," Browne said. "Pollutants on microplastics also increased the vulnerability of lugworms to pathogens while the plastic itself caused oxidative stress."
As test subjects, lugworms were not chosen at random. They are found in the United States and Europe, where they comprise up to 32 percent of the mass of organisms living on some shores, and are consumed by birds and fish and used as bait by fishermen. When the worms feed, they strip the sediment of silt and organic matter, giving rise to a unique and diverse number of species. Consequently, governments use this species to test the safety of chemicals that are discharged in marine habitats.
"They also suffer from mass mortalities during the summer," Browne said of the worms. "In the areas where a lot of the mortalities occurred, there has been extensive urban development so some mass mortalities could be potentially tied to plastic. On a hot summer's day when the tide is out, these organisms cook slightly because their hydrogen peroxide levels increase. And we found that the plastic itself reduces the capacity of antioxidants to mop up the hydrogen peroxide."
Although sand transferred larger concentrations of pollutants - up to 250 percent - into the worm's tissues, pollutants and additives from microplastic accumulated in the gut at concentrations between 326 percent and 3,770 percent greater than those in experimental sediments.
The pollutant nonylphenol from microplastic or sand suppressed immune function by more than 60 percent. Triclosan from microplastic diminished the ability of worms to engineer sediments and caused mortality, each by more than 55 percent. Triclosan, an antibacterial additive, has been found in animal studies to alter hormone regulation. Microplastic also increased the worms' susceptibility to oxidative stress by more than 30 percent.
These chemicals are known as priority pollutants, chemicals that governments around the world have agreed are the most persistently bioaccumulative and toxic. Previous work conducted by Browne and his colleagues showed that about 78 percent of the chemicals recognized by the U.S. Environmental Protection Agency are associated with microplastic pollution.
"We've known for a long time now that these types of chemicals transfer into humans from packaged goods," Browne said. "But for more than 40 years the bit that the scientists and policymakers didn't have was whether or not these particles of plastic can actually transfer chemicals into wildlife and damage the health of the organism and its ability to sustain biodiversity. That's what we really nailed with the study."
Gotta Sample 'Em All! Underwater Pokéball Captures Ocean LifeNews
A new device developed by Wyss Institute reseachers safely traps delicate sea creatures inside a folding polyhedral enclosure and lets them go without harm using a novel, origami-inspired design. The ultimate aim is to allow the sea creatures to be (gently) analyzed in high detail.READ MORE
Deep-Sea Conditions Impact Oil DegradationNews
Degradation rates of oil were slower in the dark and cold waters of the depths of the Gulf of Mexico than at surface conditions, according to an international team of geoscientists trying to understand where the oil went during the Deepwater Horizon oil spill.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:c644c742-f5dc-46b5-8ece-1f611ff47b62> | 2.921875 | 1,133 | News Article | Science & Tech. | 23.852094 | 95,555,478 |
Director, Australian International Gravitational Research Centre
As a young boy captivated by the Russians launch of Sputnik – the world’s first artificial satellite – David Blair’s future career was set in stone.
The celebrated UWA Winthrop Professor and Australian International Gravitational Research Centre Director has spent decades investigating the existence of gravitational waves. Dedicated to bestowing an interest in the wonders of science upon future generations, David also co-founded the Gravity Discovery Centre in Gingin for the promotion of science in the State.
First predicted by Albert Einstein about 100 years ago, gravitational waves are vibrations or sounds that travel through empty space. Pairs of black holes that spiral together could form a gravitational wave. These waves, the source of much debate between physicists over the years, are said to have been produced at the time of the Big Bang. Devoting his life to listening to the signals, David likened the discovery of such a thing to hearing the birth of the universe.
For years, UWA has been part of an international project team that has set up gravitational wave detector equipment to measure the waves.
“Vast amounts of gravitational wave energy are believed to be continually passing through the earth. The collaboration of almost 1000 physicists has spent decades developing gravity receivers based on laser technology.”
The gravity receivers are designed to pick up powerful bursts of energy from the formation of black holes in the distant universe.
"The birth of a black hole creates a tsunami of rippling space. More energy is given out than our sun emits in a billion years. These enormous bursts of energy travel at the speed of light, and so far we cannot even detect them."
The physicist and keen advocator of science and education has won numerous awards, including the Western Australian Premier's Science Award for Scientist of the Year; National Medal for Community Service; Centenary Medal (for Promotion of Science) and Clunies Ross Medal for Science and Technology.
In a world first, scientists have observed ripples in the fabric of space-time called gravitational waves, arriving at the earth from a cataclysmic event in the distant universe. This confirms a major prediction of Albert Einstein’s 1915 general theory of relativity and opens an unprecedented new window to the cosmos.
Thea Kurniawan brings a new definition to ‘pursuing impossible’. The Bachelor of Science s...
Agricultural engineer Andrew Guzzomi is combining his passion for engineering with a desir...
Growing up in the small town of Bahjoi in India, Dr Rajeev Varshney was always inter...
After a cycling incident in 2013, Zac was told he’d be lucky to walk again. Yet, following... | <urn:uuid:39cbfcad-3de8-4895-a696-dc5bc5e80834> | 2.6875 | 557 | About (Org.) | Science & Tech. | 38.666684 | 95,555,483 |
Convergent, divergent and transform boundaries represent areas where the Earth’s tectonic plates are interacting with each other. Convergent boundaries, of which there are three types, occur where plates are colliding. Divergent boundaries represent areas where plates are spreading apart. Transform boundaries occur where plates are sliding past each other.
Oceanic vs. Continental Convergent Boundaries
When oceanic plates collide with continental plates, the denser oceanic plate is forced under the lighter continental plate. This process has three geological results. The continental plate is lifted upwards, creating mountains. As the oceanic plate subducts, a trench is formed. Finally, as the descending plate melts, it leads to volcanic activity on the surface of the continental plate. This is occurring where the oceanic Nazca Plate is subducting under the South American Plate, creating the Andes Mountains and the Peru-Chile Trench.
Oceanic vs. Oceanic Convergent Boundaries
When two oceanic plates collide, the older denser plate subducts. The results of this tectonic collision are similar to those involving oceanic and continental plates. A deep trench is formed on the seafloor. For example, the formidable Marianas Trench has been formed by the subduction of the Philippine Plate under the Pacific Plate. There is also undersea volcanic activity, which over time can form island chains. The Aleutian Peninsula in Alaska is an example of this type of island arc.
Continental vs. Continental Convergent Boundaries
When continental plates collide into one another, neither plate can subduct under the other because they are equally light and buoyant. Instead, they are pressed together under intense pressure. This pressure creates buckling and slipping, both vertically and horizontally. This is the process by which the largest mountains on Earth have been formed. For example, when the Indian and Eurasian Plates collided around 50 million years ago, the result was the formation of the Himalayas and Tibetan Plateau.
Divergent boundaries occur where plates are spreading apart. This spreading is caused by convective forces in the molten magma below them. As they slowly spread apart, this fluid basalt lava fills the gap and quickly solidifies, forming new oceanic crust. When this occurs with continental plates, a rift valley is formed, such as the East African Rift. When this occurs with oceanic plates, a ridge is formed on the seafloor, such as the Mid-Atlantic Ridge. Iceland actually sits atop the Mid-Atlantic Ridge. Eventually, the island will be split into two separate land masses.
Transform boundaries occur where plates are sliding past one another. They are also called conservative boundaries because crust is neither destroyed nor created along them. Transform boundaries are most common on the seafloor, where they form oceanic fracture zones. When they occur on land, they produce faults. These fracture and fault lines typically connect offsetting divergent zones. For example, the San Andreas Fault connects the South Gorda divergent zone, north, to the East Pacific Rise, to the south. On the north end, this fault continues out into the Pacific Ocean as the Mendocino Fracture Zone. Along the San Andreas Fault, the Pacific Plate is moving to the northwest and the North American Plate is moving to the southeast. | <urn:uuid:376fc741-cf43-4e1c-9420-554039780594> | 4.4375 | 677 | Knowledge Article | Science & Tech. | 37.168155 | 95,555,487 |
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Black Holes Devour Stars a Lot More Frequently Than We Thought
Astronomers recently discovered that stars are destroyed by black holes 100 times more often than originally thought during a phenomenon known as tidal disruption events.
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Realizing the dream of space: Astronaut Peggy Whitson on leaving Earth for the first time03:38
Particle physics can't shrink you like Ant-Man... yet04:49 | <urn:uuid:5c1889aa-52fd-4081-8958-7e0764ce28fb> | 2.53125 | 178 | Content Listing | Science & Tech. | 43.505 | 95,555,509 |
or log in
Cold and warm fronts are formed where bodies of cold and warm air meet.
Soil is the loose, uppermost, fertile layer of the Earth’s crust.
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We can often observe spectacular atmospheric phenomena. Let's see how some of these are formed.
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Test Driven Development is Your Friend
Test Driven Development is Your Friend
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I have seen lots developers are not seeing benefits of Test Driven development. When you do Test Driven development there are lots of benefits. So I thought it will be good idea to write a blog post about it.
What is Test Driven Development:
As per wikipedia Test Driven Development is
Test-driven development (TDD) is a software development process that relies on the repetition of a very short development cycle: first the developer writes an (initially failing) automated test case that defines a desired improvement or new function, then produces the minimum amount of code to pass that test, and finally refactors the new code to acceptable standards
Kent Ben an American software engineer and creator of extreme programming rediscovered this technique. There are three main indicators of Test Driven development.
There are few steps of test driven development.
- Create a test that fail (Red Indicator).
- Write some code (Green Indicator).
- Test again and see whether test is passed or not? If not refactor your code until it passed test(Green Indicator).
Introduction to Test Driven Development
Test Driven Tutorial-Presentation
Test Driven Development and Microsoft.NET:
There are lots framework available for Microsoft.NET which you can use to develop your software in test driven way. Even Microsoft Visual Studio also provides Test Explorer in built to create and run test from Visual Studio itself.
Following is a complete list of Mature framework available for Test Driven Development and supported in Visual Studio itself.
- MS Test
Following link will give you guidelines/best practices for Test Driven Development in Microsoft.NET World.
Guidelines for test driven development
Following are few more links that will give you head start with test driven development with Visual Studio and Microsoft.NET world.
Quick Start: Test Driven Development with Test Explorer
Walkthrough: Using TDD with ASP.NET MVC
NET TDD (Test Driven Development) by example
A great video from Scott Alen about TDD and Test driven development with ASP.NET MVC. It will be eye opener for you if you are not doing Test Driven Development. http://pluralsight.com/training/Player?author=scott-allen&name=mvc4-building-m9-tests&mode=live&clip=0&course=mvc4-building
Benefits of Test Driven Development:
Following are benefits of test driven development.
- It will definitely will decrease your regression testing significantly. You don’t have to worry about test while you edit or refactor your code. You just need to run code and see whether your code passes existing test or not. You will not fear about breaking something while you add new functionality to existing functionality you need to run the existing tests to see whether your code is working fine or not.
- Refactoring of your code will become easier and you will not break your functionality while to refactor your code.
- Your architecture will be better designed due to test driven development because you know what things will be break if you make this changes.
- Code reviews will be easy. The person who is reviewing your code will first look at the test created and better understands existing code with the help of test performed. You don’t have to explain each and every lines of code to him.
- Your code stability will increase. Because if you write code to pass test means that every bit of your code coverage is good and confirmed to pass tests written then your code will be more stable.
- Accountability of code will be increase. Let’s take general scenario most of the time developers does not accept that his/her code break things but when you have tests written they need to make sure that all tests are must pass and that’s why accountability of developer towards their code will increase.
- Better planning and estimation: Now there will be a test written for everything so you can check every bit of business logic to pass tests. So estimation of software development and planning of that development task completion will be near to perfect.
- Reduce bug : With test driven development there will be very less bug because tests are written for all the scenarios and bug will be detected at the time of development only.
- It’s faster then righting code without test- Take scenario you have create a feature in module and deployed it to testing server where doing testers review they found x number of bugs. So you again need to fix that bugs and give them for testing and this cycle will go on and on until testers are satisfy with feature and specification. Now consider time given for deployment, publishing of code on test server as well testers time for regression testing time. You will realize that it will take more time then writing tests.
Hope you like it. Stay tuned for more.
Published at DZone with permission of Jalpesh Vadgama , DZone MVB. See the original article here.
Opinions expressed by DZone contributors are their own. | <urn:uuid:920cc599-28b6-4ebf-bfe3-11809f34b106> | 2.625 | 1,080 | Personal Blog | Software Dev. | 46.839854 | 95,555,560 |
International Biodiversity Day is observed every year on 22nd May, and this year’s theme is “Celebrating 25 years of Action for Biodiversity”. The day was observed at the Youth Centre in Thimphu with participations of more than 150 students from schools around Thimphu, and around 50 researchers and official guests from conservation and funding sector. The event is focused on the students to create awareness on the importance of biodiversity. Various poster demonstrations were carried out, which included recently discovered new species to science, new records for the country, Access and Benefit Sharing (ABS) Policy, herbarium techniques, etc. The event included bioblitz for students around the Ecological Park, and seminars on biodiversity such as bees and wasps, tiger, birds, etc.
During the event four publications by the National Biodiversity Centre were also launched, namely, Continue reading Post ID 7590
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EESC 2207 Environmental Systems: Earthquakes (Spring: 2 )
Earthquakes are among the most frightening and devastating of natural hazards, often resulting in catastrophic loss of life and property. Earthquakes are also among the most fascinating of natural phenomena. Although the basic global scale characteristics of earthquakes are well understood in the context of the theory of plate tectonics, considered in detail earthquakes are among the most complex and unpredictable of earth processes. This course is part of the Environmental Systems introductory sequence (EESC2201-EESC2208) for Environmental Geoscience majors.
Instructor(s): Alan Kafka
Last Updated: 24-Jun-17 | <urn:uuid:4f3671b2-a299-4185-a49e-86c3d6f4db3e> | 2.96875 | 137 | Product Page | Science & Tech. | 15.0375 | 95,555,614 |
Einstein's theory of relativity
, we are told, (1) redefined the concepts of space and time, showing that accepted notions of space and time were no longer universal, (2) showed that space and time were completely related, and (3) and did away with the concept of ether.
As you're probably starting to see, Einstein's theory of relativity
Einstein's Theory of Relativity
has finally been proved this month, thanks to the Hubble.
If time is eliminated as a factor, some scientists think that it will be easier to reconcile Einstein's theory of relativity
with the equations of gravity.
Both my boxer shorts and Einstein's Theory of Relativity
are safe right now," chuckled the learned academic with glee.
Then there were the stories that were just too wild to be true: Neutrinos appeared to violate Einstein's theory of relativity
by flying faster than light, but other work suggests they were doing no such thing.
Their startling discovery effectively drives a coach and horses through dear old Einstein's theory of relativity
(you remember his famous equation E=mc) which underpins just about every science lesson ever held.
Lead researcher Dr Antonio Ereditato has labelled the results as "crazy" because Albert Einstein's theory of relativity
- which has been the basis of physics for a century - depends on the idea that nothing can exceed the speed of light in a vacuum.
Many people are of the opinion that with Einstein's theory of relativity
, old classical physics is no more in vogue.
Bintley commissioned Matthew Hindson - who shares his interest in science and the cosmos - to create the score and the result is a powerfully emotive partnership in which choreographer and composer attempt to simplify Einstein's theory of relativity
In Einstein's days, as a famous saying goes, only twelve people in the world really understood Einstein's theory of relativity
What is needed is a scale of lesser deductions to be applied to returns including stake, but when I went before a Tattersalls sub-committee some years ago to explain the arithmetic involved, the blank faces of the supposed betting experts made me think it would have been easier to try to explain Einstein's Theory of Relativity
This paper answers twelve most common questions on the basics of Einstein's theory of relativity
But if you are like me, you do not realize that Einstein's theory of relativity
extends much farther than we thought and perhaps more interesting is that Einstein was much more prolific than 'just' coming up with relativity.
Part of Albert Einstein's theory of relativity
, this formula says that mass can be converted into energy, and is the basis for the development of nuclear power and weapons. | <urn:uuid:7850221a-4de1-47b5-90a2-09eef6098631> | 2.96875 | 551 | Content Listing | Science & Tech. | 17.931843 | 95,555,629 |
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Costa Rica, Panama, Colombia (type locality), Trinidad, Brazil (GB, RJ, SP), Paraguay. Costa Rica: throughout country to about 1000m elevation.
This species inhabits wet to moist climate areas, in mature forest or second growth vegetation. In lowland sites it can occur in both mature and second growth forest, but at higher elevations is increasingly restricted to open or disturbed habitats. Workers are diurnal. The species is relatively common in canopy fogging samples at La Selva Biological Station.
Nests are in narrow-guage dead stems. Most nests I have encountered have been in stems 4-10mm outside diameter. Nests can be populous: a nest I found in a dead Cecropia petiole lodged in low vegetation contained 319 workers. Nests commonly occur in low vegetation, so the species is frequently encountered and collected.
Prior to this posting I mistakenly identified this species as trapezoideus Mayr. I examined Alex Wild's images of Mayr types and discovered that excisus and trapezoideus have a similar mesosoma shape, but excisus has bare cheeks and trapezoideus has hairy cheeks. The two species are sympatric in parts of South America, judging from some of my own collections from southern Guyana. Click here for Alex Wild type images.
Mayr, G. 1870. Formicidae novogranadenses. Sitzungsber. Kais. Akad. Wiss. Wien Math.-Naturwiss. Cl. Abt. I 61:370-417.
Alto Paraná, Canindeyú (ALWC, IFML, INBP, LACM). Literature records: Cordillera (Forel 1911b).
Found most commonly in these habitats: 64 times found in montane wet forest, 7 times found in Entre SHO y SSE, 3 times found in CCL 400, 6 times found in SURA 850M, 5 times found in CCL 700m., 4 times found in rainforest, 0 times found in Semideciduous seasonal forest, 5 times found in lowland rainforest, 4 times found in 2º lowland rainforest, 5 times found in rainforest edge, ...
Found most commonly in these microhabitats: 32 times Sobre Vegetacion, 12 times beating veg., 10 times beating vegetation, 5 times ex sifted leaf litter, 5 times on low vegetation, 4 times Sura, 1 times nest in dead stem Lantana, 4 times Copa de arbol, 2 times nest in dead stick, 3 times Malaise trap, 2 times in dead stick, ...
Collected most commonly using these methods: 68 times Fogging, 32 times Sweeping, 34 times Malaise, 22 times Beating, 7 times Foggin, 5 times miniWinkler, 2 times Search, 2 times beating vegetation (3 hours), 2 times flight intercept trap, 0 times Manual sampling, 1 times baiting, ...
Elevations: collected from 5 - 1410 meters, 290 meters average | <urn:uuid:2121390d-53cd-4493-9cff-5bffcc3a6427> | 2.734375 | 666 | Knowledge Article | Science & Tech. | 57.408349 | 95,555,651 |
Ant diversity marks restoration progress
When it comes to restoring grasslands, ecologists may have another way to evaluate their progress—ants.
South Dakota State University graduate student Laura Winkler collects specimens to determine the diversity of ant populations in restored grasslands in eastern South Dakota. Her research will help scientists track the progress of U.S. Fish and Wildlife Services restoration efforts.
The more diverse the ant population, the closer a restored section of grassland is to its original state, according to Laura Winkler, who recently completed her master’s degree in plant science, specializing in entomology, at South Dakota State University. When it comes to native grasslands, ants are “ecosystem engineers.”
Ecological role of ants
Ants play many ecological roles, Winkler explained. “They aerate the soil, cycle nutrients and play a role in plant defense and seed dispersal. Ants move more soil than earthworms, plus they are food for lots of reptiles and birds.”
Some ant species support colonies of plant-feeding insects, such as aphids or plant hoppers, even protecting them from predators. “It’s like having dairy cattle,” Winkler said. Through this technique, the ants consume the sugar-rich honey dew the aphids secrete, much as humans use cow’s milk. When the ants are in need of protein, they simply eat the aphids.
Ants also distribute organic matter by moving dead insects into the colonies and their dead nest mates away from the colonies, Winkler added.
Comparing restored, undisturbed grasslands
Winkler compared tracts of restored grasslands to undisturbed ones at three sites in eastern South Dakota--Sioux Prairie in Minnehaha County, Oak Lake Field Station in Brookings County, and Spirit Mound in Clay County. The U.S. Fish and Wildlife Service manages the restored areas, while the undisturbed area at Sioux Prairie is managed by the Nature Conservancy, Oak Lake by SDSU and Spirit Mound by the S.D. Game, Fish and Parks Department.
Originally from Des Moines, Iowa, she began working with ants as an undergraduate at Iowa State University focusing on how burning and grazing affect species diversity. Her SDSU graduate research assistantship on ant biodiversity and natural history was funded through the Meierhenry Fellowship. Her research adviser was entomologist Paul J. Johnson, professor of plant science.
Variation with age
The U.S. Fish and Wildlife Service sites that had once been crop or pasture land were restored anywhere from one to four years ago, according to Winkler. This involved taking the areas down to the bare ground and then seeding native grasses. Winkler used data from multiple sites taken over a one-year period.
As expected, the younger sites had fewer ant species, with the numbers and diversity increasing over time. The restoration areas at age 1 had seven different species, while at age 2, the number had increased to nine and by age 3 to 10 species, Winkler reported. She expected the fourth year restorations to be even closer to the 17 species present in the undisturbed remnants, but what she saw was a slight decrease to eight species.
“The drought last year and then a wet spring also affects that vegetation, what’s going to survive and how many of the ants are out foraging,” Winkler pointed out.
She suspects that management techniques may also have played a role. “Some sites may have been burned more frequently,” she noted, to control weeds.
“We’ve got a sneak peek of what can happen,” Winkler said, but more long-term research is needed. Based on other research, she anticipates that the restored areas should peak in terms of species diversity within seven to eight years.
Winkler also looked at how these ant species function. The younger restorations areas tend to have ants that are generalists who can go anywhere, but the older restorations tend to have more specialists, such as soil-dwelling ants, who are more particular about where they live, Winkler explained. The more dominant specialists push out some of the generalists.
“You’ll have ants everywhere,” she pointed out, but the greater the diversity, the more niches are being filled, and the more successful the restoration effort.
About South Dakota State University
Founded in 1881, South Dakota State University is the state’s Morrill Act land-grant institution as well as its largest, most comprehensive school of higher education. SDSU confers degrees from eight different colleges representing more than 175 majors, minors and specializations. The institution also offers 29 master’s degree programs, 13 Ph.D. and two professional programs.
The work of the university is carried out on a residential campus in Brookings, at sites in Sioux Falls, Pierre and Rapid City, and through Cooperative Extension offices and Agricultural Experiment Station research sites across the state.
Christie Delfanian | newswise
Upcycling of PET Bottles: New Ideas for Resource Cycles in Germany
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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.
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- Swift is the language used to make apps for iPhone, iPad, and Mac OSX (desktop) apps.
- Why Swift? Well, You don’t really have a choice. Apple decided that part for you. The rule is: if you want to make an iPhone app, and get it into the Apple Store, then you’re going to have to develop it using Apple’s Swift programming language.
- Before you start learning Swift, ask yourself: do you really need your project to be an iPhone app? If not, a prototyping tool might be the quickest way for you to develop a Minimum Viable Product. My first choice for iPhone prototyping would be Keynotopia, but also there are some great questions to check out over at Quora.
What is iOS? How to Learn Get Started Today
- Read Swift vs. Objective-C (5 minutes)
- Download Xcode from Apple’s App Store. Note: you’ll need an Apple computer to develop iOS apps. Windows won’t work (20 minutes).
- Browse the additional resources below, and choose the one that’s best for your next step! | <urn:uuid:f22d5f00-4a66-494d-8328-9fe96fe09aa5> | 2.84375 | 245 | Tutorial | Software Dev. | 70.029567 | 95,555,680 |
By Alister Doyle
| MARRAKESH, Morocco
MARRAKESH, Morocco Drive your car 4,000 km (2,500 miles) and its greenhouse gas emissions will melt three square metres (32 square feet) of ice on the Arctic Ocean, according to a study on Thursday that found a direct link between carbon dioxide and the shrinking ice.Examining long-term trends for ice floating on the ocean since the 1950s, scientists in Germany and the United States projected the ocean around the North Pole would be ice-free in summers by the mid-2040s at current levels of emissions.In the historical records, they found that every tonne of carbon dioxide emitted to the atmosphere meant on average the loss of three square metres of ice in September, when the ice reaches a minimum extent before expanding in winter.That made it possible to "grasp the contribution of personal carbon dioxide emissions to the loss of Arctic sea ice," scientists at Germany's Max Planck Institute for Meteorology and the U.S. National Snow and Ice Data Center wrote in the journal Science.Each passenger taking a return flight from New York to Europe, or driving a gasoline car 4,000 kms, would emit about a tonne of carbon dioxide, they estimated.
A long-term retreat of Arctic sea ice is already causing profound changes, disrupting the lives of indigenous peoples while opening the region to more oil and gas exploration and shipping.Scientists usually deal in more abstract terms such as billions of tonnes of greenhouse gases. "Here it's more personal," lead author Dirk Notz of the Max Planck Institute told Reuters.
Some other scientists said the study was simplistic."This sounds like a rather crude equation," Peter Wadhams, a professor of ocean physics at Cambridge University, told Reuters.He said ice could disappear from the Arctic Ocean as early as 2017 or 2018 because of other factors triggered by man-made climate change, such as shifts in winds and rising sea temperatures.
In September 2016, sea ice shrank to an annual minimum extent of 4.14 million square kilometres (1.60 million square miles), matching 2007 as the second smallest in the satellite record behind 2012.Thursday's study said goals set under the 2015 Paris Agreement for curbing emissions were insufficient to avert the loss of ice. Governments meet in Marrakesh, Morocco, from Nov. 7-18 to work out how to implement the agreement. (Reporting By Alister Doyle)
This story has not been edited by Firstpost staff and is generated by auto-feed.
Updated Date: Nov 03, 2016 18:15 PM | <urn:uuid:bd5c421e-db27-48ef-a067-fffb0ff9ddce> | 3.046875 | 529 | Truncated | Science & Tech. | 48.738084 | 95,555,682 |
The mission of this International Polar Year (IPY) project is to uncover secrets of the enigmatic Gamburtsev subglacial mountains that are buried by up to 4 km of ice; to hunt for the oldest ice on our planet; to study subglacial lakes and to discover new clues of past, present and future climate change.
The Gamburtsev subglacial mountains are thought to be the birthplace of the vast East Antarctic Ice Sheet. This project will reveal clues to how the mountains were formed and provide scientists with the best location for future ice core drilling campaigns.
Geophysicist Dr Fausto Ferraccioli of BAS is leading the UK science effort. He says,
“This is both an exciting and challenging project. It is a bit like preparing to go to Mars. Because of IPY, scientists from six countries are working together to do the unthinkable, to explore the deep interior of East Antarctica – one of the last frontier regions of our planet. For two and a half months our international teams will pool their resources and expertise to survey mountains the size of the Alps buried under the ice sheet that currently defy any reasonable geological explanation. At the same time, we will hunt for ice that is more than 1.2 million years old. Locked in this ancient ice is a detailed record of past climate change that will assist in making better predictions for our future.”
Working at high altitude in temperatures of minus 40ºC, science teams will operate from two remote field camps to complete the first major geophysical survey to ‘map’ the mysterious landscape that lies beneath the vast ice sheet.
The science teams will use a range of state-of-the-art technologies to build an unprecedented 3-dimensional view of this secret world. BAS and the US National Science Foundation (NSF) will work together with the German Federal Institute for Geosciences and Natural Resources (BGR) to deploy two survey aircraft, equipped with ice-penetrating radar, gravimeters and magnetic sensors. US, Chinese and Japanese teams will study the deeper structure under the Gamburtsev subglacial mountains using seismology.
Mounting this scientific expedition is an enormous and challenging international effort involving six countries, nine aircraft and two deep-field science camps. All this is supported from US Amundsen-Scott Station at South Pole, McMurdo Research Station, from the Australian Davis Station and the BAS Rothera Research Station. Science and support teams on the Chinese tractor-train from South Pole to Zhongshan Station will sample ice cores and decommission the UK-Australian Camp.
Professor Nicholas Owens, Director of British Antarctic Survey says,
“There’s an amazing history of our planet locked in Antarctica’s ice and rocks. It’s only now that we have the technology to start uncovering the secrets from this unique natural laboratory. This is really big science and it can be done only by working with partners from other national Antarctic programmes. It’s exciting, very demanding in terms of physical hardship and logistics coordination, but this joint effort will yield the kind of information that scientists need to understand our past, present and future climate. In a changing world, with so much uncertainty about our future it is absolutely crucial for society that we find answers to fundamental questions about our Earth.”
Athena Dinar | alfa
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19.07.2018 | NASA/Goddard Space Flight Center
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The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
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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.
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As many of you will undoubtedly know, mathematics underpins much of our everyday life, in aspects such as love and warfare, to ancient creatures and Mean Girls: areas which have been previously explored in past articles. But what makes mathematics so beautiful is that it allows us to solve problems, both simple and complex. Some of these problems may initially seem counter-intuitive, or not at all obvious. But by expressing them in mathematics, their true nature/solution can be revealed.
A famous one to play at parties! In a group of 23 people, there is approximately a 50% chance that two people will share the same birthday, and a 99.9% chance with 70 people. But, to get 100%, if we include pesky leap years, we need 367.
This (slightly paraphrased) problem is as follows: You’re on a game show, and you have a choice of three doors. Behind two doors are deadly scorpions, but behind the other door is a Chalkdust T-shirt! You pick a door, say No 1, and the host, who knows what’s behind the doors, opens another door, say No 2, containing an evil scorpion. He then proposes to you: “Do you want to pick door No 3?” How do you increase your chances of winning that awesome T-shirt?
The curious tale of the accountant
This problem was actually initially presented to me only a week ago during a maths circle here at UCL. Throughout the year 2016, the accountant noticed that in any five consecutive months, his income was less than his expenses. But overall, his income was more than his expenses. How can this be? A small hint:
$12\mod5 \not \equiv 0$
We all can remember spending countless hours trying to solve the pesky Rubik’s Cube, with most of us giving up in frustration and going on to solve simpler puzzles (or eat pizza). But in fact, all positions of the Rubik’s Cube can be solved in 20 positions (or less!).
And while I’m sure that that $\exists$ many more curious problems, half the fun of mathematics is discovering them yourself (and then sharing them)! If you have any curious problems to share tweet us @chalkdustmag and you might even be featured in future articles!
Question Marks: Flickr user Valerie Everett, CC BY-SA 2.0
Birthday cakes: Flickr user Felix, CC BY-SA 2.0
Money: Flickr user 401(K) 2012, CC BY-SA 2.0
Rubik’s Cube: Flickr user Sonny Abesamis, CC BY-SA 2.0
Rubik’s Cube is a registered trademark of Seven Towns, Ltd.
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Geoscientists of Jena University analyze soil contamination through melt waters at airports
Spring has arrived in Europe with mild temperatures and sunshine. Where just a few weeks ago the ground was frozen and partly covered in snow and ice, it is now thawing. This doesn't only have an impact on the flora and fauna.
Thawing results in soil and the groundwater at airports being impacted by chemicals, which are contained in melt water. The reason: Airports have to use de-icing agents during the winter, which end up on unpaved areas and infiltrate into the soils during snowmelt.
“Admittedly, airport operators in EU-countries are compelled to sustain a good condition of the groundwater or at least to avoid detrimental concentrations of pollutants in the groundwater,“ says PD Dr. Markus Wehrer from the Friedrich Schiller University Jena (Germany).
“However, it is common practice that along the runways huge amounts of de-icing fluids infiltrate into the ground,“ the Hydrogeologist adds. It does indeed make sense to use the natural self cleaning capacities of the soil. However, the de-icing chemicals have a negative impact on groundwater quality and the functions of the soil. This was shown in a new study of a team of researchers around Prof. Dr. Kai Uwe Totsche at the Jena Chair of Hydrogeology.
In the science magazine “Environmental Science and Pollution Research“ the scientists of the University Jena wrote that chemicals like propylene glycol und potassium formate are being degraded by micro-organisms living in the soil and therefore don't get into the groundwater – at least not straight away (DOI: 10.1007/s11356-014-3506-3). “On the other hand, heavy pollution through these substances leads to a dramatic decrease of oxygen content in soils and groundwater,“ Heidi Lissner, the first author of the study explains: This is because the microbes use oxygen to degrade the pollutants.
“The more of these substances they have to metabolize, the more oxygen they use for this,“ says the geoscientist, who developed the results – which are now published in the study – within the framework of her PhD thesis. As a consequence iron and manganese oxides, which stabilize the intergranular cement of the structure of the soil, dissolve.
For their study the Jena team of researchers analyzed the soil around the airport of the Norwegian capital Oslo. There, every winter about 1,000-1,500 tons of de-icing agents are used. “At the same time, the airport is situated directly next to the largest superficial aquifer in Norway, the Romerike-Aquifer,“ explains Dr. Wehrer, who supervised Heidi Lissner's work together with Prof. Dr. Totsche. The geoscientists took soil core samples close to the runway of the airport and examined them.
“We wanted to find out, how the de-icing agents affect the condition of the soil and the percolating water,“ Heidi Lissner explains. In order to do so, the young scientist loaded soil cores with water that contained de-icing chemicals and thus simulated a “thawing event“. She collected the seepage water after it passed through the soil cores, followed by an examination for de-icing chemicals as well as the oxygen content and additional parameters.
According to the Jena scientists, their exemplary results can be transferred to the situation at other airports. “Chemicals for de-icing aircrafts as well as runways are used wherever there is snow and ice in winter,“ Dr. Wehrer says. He stresses that, additionally, measures to reduce the oxygen content in the soil around airports could be deducted from the new scientific results. Apart from installing specific areas, which allow the thawing water to seep away in a controlled manner, a controlled use of bacteria in the soil, which are specialized in the degradation of these chemicals, is conceivable.
This requires an additionally improved oxygen supply in the soil. Also, alternative substances, which can be used for the degradation of pollutants similar to the way in which oxygen works, may be supplied. Moreover, the texture of the soil could be shaped in a way that delays the seepage of the polluted soil water. Through a longer interval, which is then available for the degradation of the substances, a lack of oxygen could be avoided, because atmospheric oxygen is transferred slowly but continuously into the soil.
Lissner H. et al. Constraints of propylene glycol degradation at low temperatures and saturated flow conditions. Environ Sci Pollut Res (2015) 22:3158–3174, DOI 10.1007/s11356-014-3506-3
Prof. Dr. Kai Uwe Totsche, PD Dr. Markus Wehrer
Institute of Geosciences
Friedrich Schiller University Jena
Burgweg 11, 07749 Jena
Phone: ++49 3641 948650
Email: kai.totsche[at]uni-jena.de, markus.wehrer[at]uni-jena.de
Dr. Ute Schönfelder | idw - Informationsdienst Wissenschaft
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Globular clusters could be up to 4 billion years younger than previously thought, new research led by the University of Warwick has found.
Imagine only knowing 15 people in the world, and as you discover more people, your knowledge expands. Scientists studying our galaxy face something similar as they make discoveries that build our understanding of the universe.
Can we tell black holes apart? Astrophysicists at Frankfurt, the Max Planck Institute for Radio Astronomy in Bonn, and Nijmegen, collaborating in the project BlackHoleCam, answer this question by computing the first images ...
Planets orbiting "short-period" binary stars, or stars locked in close orbital embrace, can be ejected off into space as a consequence of their host stars' evolution, according to new research from the University of Washington.
When LIGO's twin detectors first picked up faint wobbles in their respective, identical mirrors, the signal didn't just provide first direct detection of gravitational waves—it also confirmed the existence of stellar binary ...
A trio of students from the University of Glasgow have developed a sophisticated artificial intelligence which could underpin the next phase of gravitational wave astronomy.
New research finds that 'Oumuamua, the rocky object identified as the first confirmed interstellar asteroid, very likely came from a binary star system. | <urn:uuid:185c4e77-6631-4814-8794-bd61e71d0499> | 3.3125 | 268 | Content Listing | Science & Tech. | 30.101703 | 95,555,723 |
Although the levels of the chemicals that the fish swam in were very low even before the upgrade, the chemicals are endocrine disrupters. They mimic estrogen and may disrupt the endocrine (hormone) system of both animals and humans, said the study's principal investigator, David Norris, PhD, an integrative physiology professor at the University of Colorado at Boulder.
Norris' team reported in 2006 that native male fish in Boulder Creek decreased in numbers with respect to females and numerous intersex fish were found downstream of the wastewater treatment plant. After a technology upgrade to the wastewater treatment plant in 2008, the reproductive disruption in the fish was far less pronounced. However, Norris said the study results should still concern people.
"The fish are a wake-up call," Norris said. "Our bodies and those of the much more sensitive human fetus are being exposed everyday to a variety of chemicals that are capable of altering not only our development and physiology but that of future generations as well."
With other scientists, Norris studied samples of the wastewater effluent, the plant-treated water that enters the stream and becomes another city's drinking water. Grants from the U.S. Environmental Protection Agency (EPA) and the city of Boulder supported this research.
They found other endocrine disrupters, including synthetic and natural reproductive steroids. They believe the chemicals come from natural female hormones and birth control pills excreted via urine and from detergents, cosmetics and other consumer products flushed down toilets and drains. The amount of estrogens in the sampled effluent was enough to explain the effects on the fish "downstream" from the treatment plant—in the river below the plant, according to Norris. The researchers saw no signs of reproductive disruption in fish upstream.
Also, the investigators exposed adult male fathead minnows to wastewater effluent they diluted with water taken from upstream of the plant. After seven days' exposure to this water, the fish had suppressed male sex characteristics and greatly elevated levels of the protein vitellogenin. Female fish make vitellogenin under the influence of estrogens, and male fish produce very little of it, so elevated levels in males indicate estrogen exposure, Norris explained.
After the technology upgrade to the wastewater treatment plant in 2008, the effluent was considerably less estrogenic to the fish. After the treatment plant's upgrade, the minnows exhibited less intense loss of male sex characteristics, an initial analysis found. "It took 28 days to get a significant elevation in vitellogenin and then only in 100 percent effluent," Norris said. "However, these improvements seen in wildlife will not substantially lessen the risk to human health because drinking water is not the major source of estrogenic chemicals for people."
Aaron Lohr | EurekAlert!
Innovative genetic tests for children with developmental disorders and epilepsy
11.07.2018 | Christian-Albrechts-Universität zu Kiel
Oxygen loss in the coastal Baltic Sea is “unprecedentedly severe”
05.07.2018 | European Geosciences Union
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
16.07.2018 | Life Sciences
16.07.2018 | Earth Sciences | <urn:uuid:f82e004d-576d-4f88-ae9b-0ff2571e9017> | 3.234375 | 1,217 | Content Listing | Science & Tech. | 35.846773 | 95,555,741 |
Just in time for the 100th anniversary to commemorate the discovery of superconductivity by the Dutch physicist Heike Kamerlingh Onnes on April 8, 1911, scientists from the Helmholtz-Zentrum Dresden-Rossendorf and the TU Dresden published their research results in the journal Physical Review B.
Headed by Dr. Thomas Herrmannsdörfer, the team from the HZDR's High Magnetic Field Laboratory (HLD) examined a material consisting of the elements bismuth and nickel (Bi3Ni) with a diameter of only a few nanometers – which is unique since it has not been achieved elsewhere so far. This was made possible through a new chemical synthesis procedure at low temperatures which had been developed at the TU Dresden under the leadership of Prof. Michael Ruck. The nano scale size and the special form of the intermetallic compound – namely, tiny fibers – caused the physical properties of the material, which is non-magnetic under normal conditions, to change so dramatically.
This is a particularly impressive example of the excellent opportunities modern nanotechnology can provide today, emphasizes Dr. Thomas Herrmannsdörfer. "It's really surprising to which extend the properties of a substance can vary if one manages to reduce their size to the nanometer scale."
There are numerous materials which become superconducting at ultralow temperatures. However, this property competes with ferromagnetism which normally suppresses superconductivity. This does not happen with the analyzed compound: Here, the Dresden researchers discovered with their experiments in high magnetic fields and at ultralow temperatures that the nanostructured material exhibits completely different properties than larger-sized samples of the same material. What's most surprising: The compound is both ferromagnetic and superconducting at the same time. It is, thus, one of those rarely known materials which exhibit this unusual and physically not yet completely understood combination. Perhaps bismuth-3-nickel features a special type of superconductivity, says Dr. Herrmannsdörfer. The physicist and doctoral candidate Richard Skrotzki, who has just turned 25, is making a vital contribution to the research results and describes the phenomenon as "the bundling of contrary properties in a single strand."
The TU Dresden and the HZDR are partners in the research alliance DRESDEN-concept which pursues the objective of making visible the excellence of Dresden research.
The original article was published under the title "Structure-induced coexistence of ferromagnetic and superconducting states of single-phase Bi3Ni seen via magnetization and resistance measurements" by T. Herrmannsdörfer, R. Skrotzki, J. Wosnitza, D. Köhler, R. Boldt, and M. Ruck as "Rapid Communication" in Physical Review B, Vol. 83, No.14 (DOI: 10.1103/PhysRevB.83.140501).
The article was classified by the editors of Physical Review as particularly valuable reading.
Dr. Christine Bohnet | EurekAlert!
Subaru Telescope helps pinpoint origin of ultra-high energy neutrino
16.07.2018 | National Institutes of Natural Sciences
Nano-kirigami: 'Paper-cut' provides model for 3D intelligent nanofabrication
16.07.2018 | Chinese Academy of Sciences Headquarters
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
16.07.2018 | Life Sciences
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Found most commonly in these habitats: 1 times found in Rainforest, 1 times found in disturbed rainforest, 0 times found in Forest, 1 times found in Rainforest edge, 1 times found in tropical rainforest.
Found most commonly in these microhabitats: 2 times in leaf litter, 1 times sifted litter (leaf mold, rotten wood), 1 times Litter sample dry rainforest along creek near swimming hole, 1 times litter, 0 times Leaf litter, 1 times in creek debris, 1 times ex sifted leaf litter, 0 times ex floodplain.
Collected most commonly using these methods: 1 times litter sample, 1 times MW 25 sample transect, 5m, 0 times Pitfall 44, 1 times Winkler.
Elevations: collected from 5 - 850 meters, 303 meters average
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Antweb is funded from private donations and from grants from the National Science Foundation, DEB-0344731, EF-0431330 and DEB-0842395. c:0 | <urn:uuid:0a4e91dc-3b4c-4e6b-975e-a8219a598aeb> | 2.75 | 314 | Knowledge Article | Science & Tech. | 58.549505 | 95,555,757 |
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Found most commonly in these habitats: 12 times found in wet sclerophyll, 11 times found in Dry sclerophyll, 0 times found in Casuarina Nothofagus forest, 0 times found in River Red Gum, 2 times found in coastal scrub, 2 times found in Mallee, 0 times found in rainforest, 1 times found in Rainforest Gully, 2 times found in medium sclerophyll, 2 times found in low scrub, ...
Found most commonly in these microhabitats: 2 times under stone, 3 times Stray foragers on low vegetation, 3 times Random foragers, 1 times ground foragers, 1 times garden, under stone, 2 times foraging column on Eucalyptus trunk, 0 times Ex rtn log, 0 times under bark, 2 times Stray ground foragers, 2 times foraging on Eucalyptus trunk, 1 times Under rock, ...
Collected most commonly using these methods: 3 times Pitfall, 0 times pitfall trap, 0 times flight intercept, 0 times pitfalls, 0 times WB line malaise over Beehive Creek, 0 times Yellow trays, 0 times Berlesate, 1 times ex pitfall trap, 1 times Malaise, 0 times Malaise trap, 0 times Sweeping foliage, ...
Elevations: collected from 2 - 3000 meters, 827 meters average
AntWeb content is licensed under a Creative Commons Attribution License. We encourage use of AntWeb images. In print, each image must include attribution to its photographer and "from www.AntWeb.org" in the figure caption. For websites, images must be clearly identified as coming from www.AntWeb.org, with a backward link to the respective source page. See How to Cite AntWeb.
Antweb is funded from private donations and from grants from the National Science Foundation, DEB-0344731, EF-0431330 and DEB-0842395. c:1 | <urn:uuid:b18bd65c-6e14-4991-a2d1-f1a4c1907723> | 2.6875 | 436 | Knowledge Article | Science & Tech. | 59.385987 | 95,555,758 |
|RHODOPHYTA : CORALLINALES : Corallinaceae||RED ALGAE|
Description: Thallus encrusting, flat and firmly attached, up to 5 cm in diameter. Large raised conceptacles with dark centre.
Habitat: Very common. Epiphytic often on Furcellaria and Laminaria but also other species. Mid-littoral and sub-littoral to over 40 m depth.
Distribution: Very common around the British Isles. Europe: Mediterranean, Portugal, Atlantic coasts of Spain and France, Baltic Sea and Norway. Atlantic coast of North America: Canada, Massachusetts, Rhode Island, Connecticut, Virginia and Florida. Further afield: West Indies, Canary Islands, Senegal and Cape Verde Isles, South Africa, Australia and New Zealand.
Similar Species: Hildenbrandia is much finer, epilithic and does not have large raised conceptacles.
Key Identification Features:
Distribution Map from NBN: Interactive map : National Biodiversity Network mapping facility, data for UK.
WoRMS: Species record : World Register of Marine Species.
|Morton, O. & Picton, B.E. (2016). Melobesia membranacea (Esper) Lamouroux. [In] Encyclopedia of Marine Life of Britain and Ireland. |
http://www.habitas.org.uk/marinelife/species.asp?item=ZM4720 Accessed on 2018-07-18
|Copyright © National Museums of Northern Ireland, 2002-2015| | <urn:uuid:54346b00-fa9c-40c5-839b-89953cdc4eb3> | 2.859375 | 330 | Knowledge Article | Science & Tech. | 29.304502 | 95,555,766 |
How is relative dating used
American physical chemist Willard Libby led a team of scientists in the post World War II era to develop a method that measures radiocarbon activity.He is credited to be the first scientist to suggest that the unstable carbon isotope called radiocarbon or carbon 14 might exist in living matter. Libby and his team of scientists were able to publish a paper summarizing the first detection of radiocarbon in an organic sample. Libby who first measured radiocarbon’s rate of decay and established 5568 years ± 30 years as the half-life. Libby was awarded the Nobel Prize in Chemistry in recognition of his efforts to develop radiocarbon dating.These treasure troves, some 50 km northwest of Johannesburg, have yielded pieces of the puzzle of human evolution for decades.Scientists initially thought Homo naledi's anatomy suggested the fossils might be as much as 2.5 million years old and were startled by evidence that suggested the species may have buried its dead, a trait long believed to be uniquely human.Archaeology and other human sciences use radiocarbon dating to prove or disprove theories.Over the years, carbon 14 dating has also found applications in geology, hydrology, geophysics, atmospheric science, oceanography, paleoclimatology, and even biomedicine.
All we need to do is find the element on the Periodic Table and read its Atomic Number: So for example, Fluorine has the symbol F and has 9 protons.Another surprise found in the discovery was the possibility of the species building tools. Tracy Kivell, a Canadian who is an assistant professor of biological anthropology in the University of Kent in the U.K., specialized in analyzing hand fossils to determine the behaviour and lifestyle of , but it is an educated guess from the bones.By referencing the cells containing 10% and 15% and not the actual numbers, when the percentage changes all you need to do is change the percentage one time in cell A12 and/or B12 instead of rebuilding all of your formulas.Excel would automatically update the discount prices to reflect your discount percentage change. | <urn:uuid:d66ded8c-76fd-4bd0-9483-ad9e42e67646> | 3.5625 | 438 | Spam / Ads | Science & Tech. | 34.978163 | 95,555,800 |
Web Components are set to change how you build front-end web applications. This course teaches you how to use the Web Components specifications to create encapsulated and reusable UI components which can be used with almost any framework or library.
Web Components represent a new way to develop reusable UI components that solve fundamental problems web developers face every day. In this course, A Practical Guide to Vanilla Web Components, you'll learn all about the Web Component specifications. First, you'll get an overview of the fundamentals of web components. Next, you'll explore the basic anatomy of a web component. Finally, you'll be shown how to use what you've learned so far by building two high quality vanilla Web Components. By the end of the course, you'll be able to write top quality encapsulated UI components which can be used in almost any front-end technology stack.
Web Components solve fundamental problems that web developers have been putting up with since the dawn of the web. These problems include style encapsulation, reusability, interoperability and the big one - framework lock in.
This course is for Web Developers who want to get ready for the next big shift in front-end Web Development.
In the course, I’ll Introduce you to the Web Components specifications and their super powers.
We’ll also create two high quality Web Components which will demonstrate the specifications in detail.
By the end of the course you’ll be able to write top quality encapsulated UI components which can be used in almost any front-end technology stack.
They’ll be reusable, extensible and themeable and I’ll also show you how to make them production ready by preparing them for cross platform use including legacy browsers such as IE11.
Web Components have been a long time coming to the Web Platform and they are finally here. With libraries, frameworks and even entire conferences dedicated to Web Components now is the perfect time to dive deep into this exciting new technology to discover the possibilities that it’ll open for you and the applications you create. | <urn:uuid:827b4dd0-c328-4c2d-868a-8b93d6440ffc> | 2.546875 | 420 | Product Page | Software Dev. | 40.747017 | 95,555,807 |
Water exchange through the Kerama Gap estimated with a 25-year Pacific HYbrid Coordinate Ocean Model
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Variations in water exchange through the Kerama Gap (between Okinawa Island and Miyakojima Island) from 1979 to 2003 were estimated with the 0.08° Pacific HYbrid Coordinate Ocean Model (HYCOM). The model results show that the mean transport through the Kerama Gap (KGT) from the Pacific Ocean to the East China Sea (ECS) was 2.1 Sv, which agrees well with the observed mean KGT (2.0 Sv) for 2009–2010. Over the time period examined, the monthly KGT varied from -10.9 Sv to 15.8 Sv and had a standard deviation of ± 5.0 Sv. The water mainly enters the ECS via the subsurface layer (300–500 m) along the northeastern slope of the Kerama Gap and mainly flows out of the ECS into the southwest of the Kerama Gap. The seasonal and interannual variations of the KGT and the Kuroshio upstream transport were negatively correlated. The Kuroshio upstream transport was largest in summer and smallest in autumn while the KGT was smallest in summer (1.02 Sv) and largest in spring (2.94 Sv) and autumn (2.44 Sv). The seasonal and interannual variations in the Kuroshio downstream (across the PN-line) transport differed significantly from the Kuroshio upstream transport but corresponded well with the KGT and the sum of the transport through the Kerama Gap and the Kuroshio upstream, which indicates that information about variation in the KGT is important for determining variation in the Kuroshio transport along the PN-line.
KeywordsKerama Gap Kuroshio Ryukyu Current HYbrid Coordinate Ocean Model (HYCOM) water exchange
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The satellite-tracked drifting buoy data are available from the Global Drifter Program (GDP), with support from their website (ftp://ftp.aoml.noaa.gov/pub/phod/buoydata/). The World Ocean Database (WOD) is available from the website (http://www.nodc.noaa.gov/OC5/SELECT/dbsearch/dbsearch. html). The HYCOM data are available for download from the Global Ocean Data Assimilation Experiment (GODAE) from the website (ftp://ftp.hycom.org/datasets/PACa0.08/).
- Boyer T P, Antonov J I, Baranova O K, Garcia H E, Grodsky A, Johnson D R, Locarnini R A, Mishonov A V, O’Brien T D, Seidov D, Smolyar I V, Zweng M M. 2013. World Ocean Database 2013. Data Science Journal, 90(49): 153–173.Google Scholar
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TeachMeFinance.com - explain North Atlantic Oscillation (NAO)
North Atlantic Oscillation (NAO) The term 'North Atlantic Oscillation (NAO)' as it applies to the area of Earth observation can be defined as ' A large see-saw in atmospheric mass between the subtropical high located near the Azores and the sub-polar low near Icealand. See Atlantic Rhythms'.
About the author
Copyright © 2005-2011 by Mark McCracken, All Rights Reserved. TeachMeFinance.com is an informational website, and should not be used as a substitute for professional medical, legal or financial advice. Information presented at TeachMeFinance.com is provided on an "AS-IS" basis. Please read the disclaimer for details. | <urn:uuid:047a7e20-688a-4c28-a6d1-b2b8dc56cfea> | 2.875 | 166 | Knowledge Article | Science & Tech. | 39.24848 | 95,555,837 |
Page Count603 Pages
About the e-Book
Building Web Components with TypeScript and Angular 4 pdf
Angular is Google's foremost framework for developing high-performing, rock-solid web applications. Unlike most web apps, Angular apps are based on components, which means they're composed of interchangeable software elements that can be replaced and re-used. Angular's modularity ensures rapid development, high reliability, and ease of upgrading.
To present these topics, the first chapters of the book provide a thorough introduction to the TypeScript language, from its new data types to its support for the document object model (DOM). After that, the book focuses on Angular and its many extraordinary capabilities, which include routing, form development, animation, and asynchronous operation. The last chapters of the book are particularly exciting, and discuss the Material Design library for Angular and the ability to customize graphics with Scalable Vector Graphics (SVG) and HTML5.
Table of Contents:
Chapter 1: Introducing TypeScript and Angular
Chapter 2: TypeScript Development Tools
Chapter 3: TypeScript Basics
Chapter 4: Classes, Interfaces, and Mixins
Chapter 5: Declaration Files and the Document Object Model (DOM)
Chapter 6: Unit Testing and Decorators
Chapter 7: Modules, Web Components, and Angular
Chapter 8: Fundamentals of Angular Development
Chapter 9: Directives
Chapter 10: Dependency Injection
Chapter 11: Asynchronous Programming
Chapter 12: Routing
Chapter 13: HTTP and JSONP Communication
Chapter 14: Forms
Chapter 15: Animation, i18n, and Custom Pipes
Chapter 16: Material Design
Chapter 17: Testing Components with Protractor
Chapter 18: Displaying REST Data with Dynamic Tables
Chapter 19: Custom Graphics with SVG and the HTML5 Canvas
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The C++ Standard Library: A Tutorial and Reference
Tableau Cookbook - Recipes for Data Visualization | <urn:uuid:56708013-3611-4a80-ae2d-f792f163fee1> | 2.5625 | 488 | Product Page | Software Dev. | 20.019664 | 95,555,876 |
For full article go to LINK IN BIO
A warming climate and the ever-increasing likelihood of multi-year #drought s may result in irreparable harm to the sustainability of the Amazon #rainforest, a new study says.
Researchers for a study published in Water Resources Research say evidence suggests the future sustainability of the Amazon rainforest and the services it provides, including biodiversity, water cycling, carbon capture and others, may require adaptive management strategies to safeguard its key benefits, according to a press release.
The study noted that the Amazon basin has, in recent years, experienced multiple “once‐in‐a‐century” droughts, impacting the region's water cycle, economy, vegetation and carbon storage.
Researchers say droughts will only worsen with #climate change and say the study highlights the need for resource managers to plan for future droughts in order to protect the Amazon's precious resources. “Future multiyear droughts will be hotter—and thus more severe—than in the past," said Overpeck. "And with the Amazon’s growing population, wildfires become a real threat during times of drought. We hope that forest managers can better prepare for these scenarios when they know the long-term drought history of the region.”
#vegansofig #spreadtheword #compassion #wildlife #quote | <urn:uuid:4e17e5a2-acb9-4173-8956-ffce984593b2> | 3.25 | 280 | News Article | Science & Tech. | 20.290488 | 95,555,916 |
Photo: Chandra image of the elliptical galaxy NGC 4261 (X-ray: NASA/CXC/A. Zezas et al.; Optical: Pal.Obs. DSS)
An image of an elliptical galaxy by NASA’s Chandra X-ray Observatory has revealed a trail of black holes and neutron stars stretching more than fifty thousand light years across space. The trail of intense X-ray sources is evidence that this apparently sedate galaxy collided with another galaxy a few billion years ago.
"This discovery shows that X-ray observations may be the best way to identify the ancient remains of mergers between galaxies," said Lars Hernquist of the Harvard-Smithsonian Center for Astrophysics in Cambridge (CfA), Massachusetts, and a coauthor on an article on the galaxy NGC 4261 in an upcoming issue of The Astrophysical Journal Letters. "It could be a significant tool for probing the origin of elliptical galaxies."
"From the optical and radio images, we knew something unusual was going on in the nucleus of this galaxy, but the real surprise turned out to be on the outer edges of the galaxy," said Andreas Zezas, also of CfA, and lead-author of the paper on NGC 4261. "Dozens of black holes and neutron stars were strung out across space like beads on a necklace."
Steve Roy | MSFC
Computer model predicts how fracturing metallic glass releases energy at the atomic level
20.07.2018 | American Institute of Physics
What happens when we heat the atomic lattice of a magnet all of a sudden?
18.07.2018 | Forschungsverbund Berlin
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
20.07.2018 | Materials Sciences | <urn:uuid:bda3b906-bbf8-493d-afcf-7dc9c222f20e> | 3.125 | 862 | Content Listing | Science & Tech. | 42.777407 | 95,555,941 |
What force is required to give mass m = 40 kg acceleration a = 2 m/c2 ?
What force is required to keep mass m = 20 kg
moving with a constant speed along straight line?
No force required
Two boxes have the same size, but one box is empty and the other has books inside.
The same force is applied to each box. What box will have the bigger acceleration?
Box with books
Boxes will have the same acceleration
Impossible to make a conclussion
According to the Second Newton's Law,
if you drop the ball it will fall down with acceleration
(because of gravity force).
Gravity on a Moon is less than on Earth.
If you drop the same ball on the Earth and on the Moon
acceleration on the Earth will be bigger than on the Moon
acceleration on the Earth will be less than on the Moon
acceleration will be the same on the Earth and on the Moon
ball will not fall down on the Moon
Gravity force applied to the monitor is 50 N.
Monitor is on a horizontal surface of table and doesn't move.
What is the magnitude and direction of surface reaction?
50 N directed horizontally
50 N directed down
50 N directed up
There is no surface reaction because monitor doesn't move
Imagine a book on the horizontal surface. without motion (at rest).
Gravity force pushing the book down with force 10 N,
but the book is remaining on the surface without motion (at rest).
What is the Net Force applying to the box?
The Net Force is 10 N and directed up
The Net Force is 10 N and directed down
The Net Force is 20 N
The Net Force is zero
Following two forces applying to the object:
one 30 N to the right (------------------->)
another 10 N to the left (<-----)
What is the Net Force?
-----> 10 N
----------> 20 N
---------------> 30 N
10 N <-----© BrainMass Inc. brainmass.com July 22, 2018, 4:42 pm ad1c9bdddf
This solution explains how to solve several problems dealing with forces. | <urn:uuid:ffc4ce5c-7161-45bd-bb9e-3cac8220b743> | 3.453125 | 457 | Q&A Forum | Science & Tech. | 71.14779 | 95,555,953 |
HEAT TRANSFER. By : Tyler J. Zunich 12/4/2013. THREE TYPES OF HEAT TRANSFER. CONDUCTION : Transfer of heat within a body or between two bodies that are touching . CONVECTION : T ransfer of heat by the circulation or movement of the heated parts of a liquid or gas.
By : Tyler J. Zunich
In my own home, there is heat transfer everyday, every second. Weather it be conduction, convection or radiation heat is always being transferred. | <urn:uuid:efb6f31f-b915-4fb7-a84a-5cfdabc50bfc> | 2.9375 | 113 | Truncated | Science & Tech. | 69.302958 | 95,555,957 |
Composite image of suspected water vapour plumes erupting at the seven o’clock position off the limb of Jupiter’s moon Europa © NASA, ESA, W. Sparks (STScI), and the USGS Astrogeology Science Center
This article was originally published on The Conversation
The Hubble Space Telescope has obtained evidence of Jupiter’s moon Europa erupting plumes of water vapour, NASA reports. Hubble first caught a glimpse of the jets in December 2012, but now more plumes have been revealed using a different technique.
The discovery is exciting, as Europa, with its large subsurface ocean, is one of the best candidates for microbial life in the solar system – despite its surface temperature being a frigid -160°C. And plumes mean that samples of microbes could be collected during a flyby, without having to land on the surface.
Europa is Jupiter’s innermost large, icy moon (only slightly smaller than our own moon) and has about 100km of ice and liquid water surrounding its rocky interior.
Scientists started getting really interested in Europa following observations by NASA’s Galileo probe of Jupiter and its moons from orbit between 1995 and 2003. These showed that Europa’s surface ice is marked by multiple generations of parallel ridges and grooves, except where this pattern has been shattered by the surface breaking apart into randomly disposed slabs (known as “chaos regions”). This can be explained if Europa’s icy shell floats on a layer of liquid water. Each grooved ridge could mark a crack that opened and closed with the changing tide during Europa’s 3.5 day orbit of Jupiter – the ridges being formed from slush that was squeezed to the surface each time the crack closed. The chaos regions would represent slabs of the ice shell that broke apart as a region of the ocean became melted from below, powered by a release of tidal heat through the ocean floor – now frozen into a new configuration.
Microbes could live near the floor of Europa’s internal ocean, feeding off the chemical energy supplied where hot water (“hydrothermal”) vents discharge chemicals dissolved out of the tidally-heated rocky interior. This is the kind of setting where life on Earth is thought to have begun. Microbes whose ancestors had developed a taste for sunlight might now be found surviving by photosynthesis (like plants) in the water drawn up and (mostly) forced down again every time a tidal crack opened. However, although Galileo searched as hard as it was able (hampered by a failed antenna) it found no signs of present-day activity, such as water venting to space.
Europa versus Enceladus
Soon after Galileo’s findings, Europa’s crown as the most active icy moon was snatched away by Enceladus, a much smaller (500km diameter) moon of Saturn, in 2005. The Cassini probe discovered jets (or plumes) of ice crystals venting to space from cracks near Enceladus’s south pole. In the decade that followed, it became clear that Enceladus has a global internal ocean between its icy surface shell and a rocky interior.
Cassini was even able to fly through the plumes, finding them to be chemically rich and bearing signs of the kind of water-rock interaction which could feed micriobial life. This raised hopes that such fly-throughs could one day find signs of microbial life (including maybe even a few ejected microbes themselves), without the need for a technically-challenging landing on the surface.
It wasn’t until December 2012 that the Hubble Space Telescope at last detected evidence for an active plume erupting from Europa, in the form of a faint ultraviolet glow caused by atoms of hydrogen and oxygen rising up to 200km above Europa’s south pole. This is probably water molecules broken apart in the harsh space environment.
However, subsequent efforts failed to find any repeat evidence, until now. The latest evidence was obtained with an enterprising new technique, using Jupiter as a light source to reveal plumes as Europa passes across its face. The Hubble Space Telescope was used to collect ultraviolet images during ten transits of Europa across Jupiter in 2014, which on three occasions revealed plumes erupting above the edge of Europa’s disc. This shows that the plumes are intermittent.
Hopefully it won’t be too long before a mission designed to detect microbial life from the plumes of Europa or Enceladus sets off to find out. It certainly seems like a worthwhile endeavour – especially after the emergence of this latest evidence. | <urn:uuid:a3f3ead1-ff89-4ae6-b195-01a19f6ed7d2> | 3.71875 | 962 | News Article | Science & Tech. | 34.188422 | 95,555,983 |
In May, an international team of scientists, veterinarians and zookeepers gathered at the Suzhou Zoo near Shanghai. Their desperate mission: to attempt the first artificial insemination ever of a softshell turtle, saving the species from oblivion.
“Even if we get just one or two hatchlings, I will be very happy,” said Gerald Kuchling, a project leader for the Turtle Survival Alliance, a nonprofit conservation organization. “Even a single one would give hope for the recovery of this magnificent animal. It would be a turn.”
Quite a turn, actually. The Yangtze giant softshell turtle – thought to be the largest freshwater turtle in the world – was once common in the Yangtze and Red rivers. But by the late 1990s, pollution, hunting, dams and development had driven it to the brink of extinction.
There are only four known specimens remaining, and only one female – an 85-year-old resident of the Suzhou Zoo. For years, biologists have been trying to coax her and her 100-year-old mate to produce hatchlings. So far the pair have disappointed scientists, with the female laying clutch after clutch of unfertilized eggs.
She was discovered only in 2007, three years after the sole other known female died at the Beijing Zoo. Desperate to find another, Kuchling and Lu Shunqing, a turtle specialist from the Wildlife Conservation Society’s China branch, had asked every zoo in the country to send them photographs of any large softshell turtles in their possession.
One image, taken at the Changsha Zoo in Hunan, caught their eye, and days later, they arrived to examine the turtle. It was indeed a Yangtze giant softshell turtle and, crucially, a female. She had once been part of a traveling animal exhibit, and became a permanent resident of the zoo shortly after the end of the Chinese Revolution in 1949.
Kuchling and Lu arranged for her transport to the Suzhou Zoo, where they hoped she and the zoo’s male specimen would begin producing more of their kind. To their delight, the animals did appear to mate, and that summer, the female laid around 180 eggs. But none proved fertile, a disappointment that would repeat itself for six years.
“The conservation world was holding its breath,” said Rick Hudson, the president of the Turtle Survival Alliance. “It’s been a lot of frustration since.”
Scientists decided to intervene. On May 6, Kuchling and Lu, with a team that included turtle experts from the United States, drained the male’s pond and used a cargo net to wrangle the 140-pound turtle onto a stack of car tires that served as a makeshift examination stand. The problem became immediately clear to the scientists: This turtle’s penis was mangled.
Two decades earlier, another Yangtze giant softshell turtle had been added to the male’s pond in an attempt to mate the animals. The second turtle turned out to be male, as well, and the two fought. The second male was killed, and the victor suffered serious damage to his shell and, it now appears, to his reproductive organ.
The team also examined the male’s sperm – extracted using electrical stimuli – and finally discovered good news. While motility was low, the sperm were viable. The scientists decided to proceed with artificial insemination of the female.
With no case studies to go on, the team had to improvise. Kuchling examined the sedated female’s cloaca with a fiber-optic endoscope to locate the compartment leading to her oviducts. Then Barbara Durrant, the director of reproductive physiology at the San Diego Zoo’s Institute for Conservation Research, deposited the semen.
“It was just a matter of delivering the semen through a small plastic tube into what we think is the correct place,” she said. “Unfortunately, there just hasn’t been that much basic reproductive physiology work done in turtles and tortoises.”
Even if it’s guesswork, artificial insemination may be the only chance to save the species. A handful of Yangtze giant softshell turtles might remain in the wild; tentative sightings have been reported in a dam reservoir on the Red River in Yunnan province. Conservationists, however, are not betting that one will be captured anytime soon.
When the female lays her first clutch of eggs, probably in late June, the scientists will know if this first effort was fruitful.
“Nobody has ever done this before, and it’s probably a long shot,” Kuchling said. “But we are all hopeful, and if it doesn’t work this time, we’ll definitely try again. Despair is not an option.” | <urn:uuid:76ddd7c4-534f-406e-90a5-b8722d6620bf> | 3.140625 | 1,017 | News Article | Science & Tech. | 48.62115 | 95,555,986 |
Parallel hole collimators are ~25–80 mm thick and contain 3–9 × 104 holes. Originally the holes were circular but are now usually hexagonal, in low and medium energy collimators, and constructed by assembling strips of lead foil. High energy collimators still have round holes, although square or triangular holes are sometimes used in high sensitivity collimators. These tend to be constructed using a casting technique (IPSM 1992). The latter has been improved recently and, since the uniformity of cast collimators is generally better than that of foil, these are now recommended in low and medium energy collimators, especially for SPET (Moore et al. 1992).
KeywordsPoint Spread Function Single Photon Emission Tomography Short Path Length Septal Thickness Convergence Point
full width at half maximum
line spread function
point spread function
single photon emission tomography
ultra high energy
very high energy
Unable to display preview. Download preview PDF.
- IPSM (1992) Report 66 quality control of gamma cameras and associated computer systems. Institute of Physical Sciences in Medicine. LondonGoogle Scholar
- Sorenson JA, Phelps ME (1987) Physics in nuclear medicine, 2nd edn. Grune and Stratton, New YorkGoogle Scholar
- Tsui BMW, Gunter DL, Beck RN, Patton J (1996) Physics of collimator design. In: Sandler MP, Patton JA, Coleman RE, Gottschalk A, Wackers FJT, Hoffer PB (eds) Diagnostic nuclear medicine, 3rd edn. Williams and Wilkins, Baltimore, pp 67–79Google Scholar | <urn:uuid:adf4dba6-fb07-464f-9e76-f0b0711da80c> | 2.703125 | 342 | Academic Writing | Science & Tech. | 38.491692 | 95,556,001 |
_Document. To(Object, Object, Object, Object) Go
To(Object, Object, Object, Object)
Returns a Range object that represents the start position of the specified item.
public Microsoft.Office.Interop.Word.Range GoTo (ref object What, ref object Which, ref object Count, ref object Name);
Public Function GoTo (Optional ByRef What As Object, Optional ByRef Which As Object, Optional ByRef Count As Object, Optional ByRef Name As Object) As Range
Optional Object. The kind of item to which the range or selection is moved. Can be one of the WdGoToItem constants.
Optional Object. The item to which the range or selection is moved. Can be one of the WdGoToDirection constants.
Optional Object. The number of the item in the document. The default value is 1.Only positive values are valid. To specify an item that precedes the range or selection, use wdGoToPrevious as the
Which argument and specify a
Optional Object. If the
What argument is wdGoToBookmark, wdGoToComment, wdGoToField, or wdGoToObject, this argument specifies a name.
When you use the GoTo method with the wdGoToGrammaticalError, wdGoToProofreadingError, or wdGoToSpellingError constant, the Range that's returned includes any grammar error text or spelling error text. | <urn:uuid:b9251d32-2eca-4129-9bed-a0c20b6ca637> | 2.859375 | 309 | Documentation | Software Dev. | 40.156283 | 95,556,028 |
Negative Refraction Metamaterials: Fundamental Principles and Applications
G. V. Eleftheriades, K. G. Balmain
- 出版商: Wiley-IEEE Press
- 出版日期: 2005-07-07
- 售價: $3,975
- 貴賓價: 9.5 折 $3,776
- 語言: 英文
- 頁數: 440
- 裝訂: Hardcover
- ISBN: 0471601462
- ISBN-13: 9780471601463
Learn about the revolutionary new technology of negative-refraction metamaterials
Negative-Refraction Metamaterials: Fundamental Principles and Applications introduces artificial materials that support the unusual electromagnetic property of negative refraction. Readers will discover several classes of negative-refraction materials along with their exciting, groundbreaking applications, such as lenses and antennas, imaging with super-resolution, microwave devices, dispersion-compensating interconnects, radar, and defense.
The book begins with a chapter describing the fundamentals of isotropic metamaterials in which a negative index of refraction is defined. In the following chapters, the text builds on the fundamentals by describing a range of useful microwave devices and antennas. Next, a broad spectrum of exciting new research and emerging applications is examined, including:
* Theory and experiments behind a super-resolving, negative-refractive-index transmission-line lens
* 3-D transmission-line metamaterials with a negative refractive index
* Numerical simulation studies of negative refraction of Gaussian beams and associated focusing phenomena
* Unique advantages and theory of shaped lenses made of negative-refractive-index metamaterials
* A new type of transmission-line metamaterial that is anisotropic and supports the formation of sharp steerable beams (resonance cones)
* Implementations of negative-refraction metamaterials at optical frequencies
* Unusual propagation phenomena in metallic waveguides partially filled with negative-refractive-index metamaterials
* Metamaterials in which the refractive index and the underlying group velocity are both negative
This work brings together the best minds in this cutting-edge field. It is fascinating reading for scientists, engineers, and graduate-level students in physics, chemistry, materials science, photonics, and electrical engineering.
Table of Contents:
1. Negative-Refractive-Index Transmission-Line Metamaterials (A. Iyer & G. Eleftheriades).
2. Passive Microwave Devices and Antennas Using Negative-Refractive-Index Transmission-Line Metamaterials (G. Eleftheriades).
3. Super Resolving Negative-Refractive-Index Transmission-Line Lenses (A. Grbic & G. Eleftheriades).
4. Gaussian Beam Interactions with DNG Metamaterials (R. Ziolkowski).
5. Negative Index Lenses (D. Schurig & D. Smith).
6. Planar Anisotropic Resonance-Cone Metamaterials (K. balmain & A. Lüttgen).
7. Negative Refraction and Subwavelength Imaging in Photonic Crystals (C. Luo & J. Joannopoulos).
8. Plasmonic Nanowire Metamaterials (A. Sarychev & V. Shalaev).
9. An Overview of Salient Properties of Planar Guided-Wave Structures with Double-Negative (DNG) and Single-Negative (SNG) Layers (A Alù and N. Engheta).
10. Dispersion Engineering: The Use of Abnormal Velocities and Negative Index of Refraction to Control the Dispersive Effects (M. Mojahedi & G. Eleftheriades). | <urn:uuid:b465dee7-85aa-4a2e-b8f4-129ee091d5d8> | 2.546875 | 849 | Product Page | Science & Tech. | 17.524617 | 95,556,033 |
as may write warnings and error messages to the standard error file (usually your terminal). This should not happen when a compiler runs as automatically. Warnings report an assumption made so that as could keep assembling a flawed program; errors report a grave problem that stops the assembly.
file_name:NNN:Warning Message Text
(where NNN is a line number). If a logical file name has been given
.file) it is used for the filename, otherwise the name of
the current input file is used. If a logical line number was given
then it is used to calculate the number printed,
otherwise the actual line in the current source file is printed. The
message text is intended to be self explanatory (in the grand Unix
file_name:NNN:FATAL:Error Message Text
The file name and line number are derived as for warning messages. The actual message text may be rather less explanatory because many of them aren't supposed to happen. | <urn:uuid:499cf2b5-27c8-435f-9311-16553b83478a> | 2.578125 | 201 | Documentation | Software Dev. | 41.269306 | 95,556,038 |
In a report, published in the August 25, 2006 issue of the journal, Science, MBL (Marine Biological Laboratory) senior scientist Bruce J. Peterson and his colleagues describe a first-of-its-kind effort to create a big-picture view of hydrologic trends in the Arctic. Their analysis reveals that freshwater increases from Arctic Ocean sources appear to be highly linked to a fresher North Atlantic.
"The high-latitude freshwater cycle is one of the most sensitive barometers of the impact of changes in climate and broad-scale atmospheric dynamics because of the polar amplification of the global warming signal," says Peterson. "It's easiest to measure these changes in the Arctic and the better we understand this system, the sooner we will know what is happening to the global hydrologic cycle."
The multi-disciplinary team of scientists led by Peterson calculated annual and cumulative freshwater input anomalies (deviations from expected levels) from net precipitation on the ocean surface, river discharge, net attrition of glaciers, and Arctic Ocean sea ice melt and export for the latter half of the 20th century. The scientists compared the fluxes to measured rates of freshwater accumulation in the North Atlantic during the same time period.
Their analysis showed that increasing river discharge and excess net precipitation on the ocean contributed the most freshwater (~20,000 cubic kilometers) to the Arctic and high-latitude North Atlantic. Sea ice reduction provided another ~15,000 cubic kilometers of freshwater, followed by ~2,000 cubic kilometers from melting glaciers. Together, the sum of anomalous inputs from all of the freshwater sources analyzed matched the amount and rate at which fresh water accumulated in the North Atlantic during much of the period from 1965 through 1995.
"This synthesis allows us to judge which freshwater sources are the largest, but more importantly shows how the significance of different sources have changed over the past decades and what has caused the changes," says Peterson. "It prompts us to realize that the relative importance of different sources will change in future decades. Creating a big-picture or synoptic view of the changes in various components of the high-latitude freshwater cycle puts the parts in a perspective where we can judge their individual and collective impact on ocean freshening and circulation."
In recent years, much attention has been given to the observed freshening of Arctic Ocean and North Atlantic and the potential impacts it may have on the earth's climate. Scientists contend that a significant increase of freshwater flow to the Arctic Ocean could slow or halt the Atlantic Deep Water formation, a driving factor behind the great "conveyor belt" current that is responsible for redistributing salt and thermal energy around the globe, influencing the planet's climate. One of the potential effects of altered global ocean circulation could be a cooling of Northern Europe within this century.
The team's comparison of freshwater sources and ocean sink records revealed that over the last half century changes in freshwater inputs and ocean storage occurred not only in conjunction with one another, but in synchrony with rising air temperatures and an amplifying North Atlantic Oscillation (NAO), a climatic phenomenon that has strong impacts on weather and climate in the North Atlantic region and surrounding continents, and the associated Northern Annular Mode (NAM) index.
Peterson and his colleagues contend that the interplay between the NAO and NAM, and continued rising temperatures from global greenhouse warming, will likely determine whether the Arctic and North Atlantic Oceans will continue to freshen. But the scientists caution that the difficultly in predicting fluctuations in atmospheric circulation makes it impossible to know where we might be headed.
"Atmospheric modes of circulation such as the NAO and NAM exert a great deal of control on net precipitation in the ocean and even on regional temperatures, and hence ice melt as well," says Peterson. "But what drives the NAO is the $64,000 question. Our inability to predict trends in the NAO/NAM means that, even if we could predict global warming very well, a large degree of uncertainty will remain in any forecasts of the decadal-centennial trajectories of the Arctic freshwater balance."
Gina Hebert | 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
20.07.2018 | Materials Sciences | <urn:uuid:1382993c-705a-44b1-93b5-766c0f923d66> | 3.15625 | 1,441 | Content Listing | Science & Tech. | 34.813863 | 95,556,046 |
University of Minnesota 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, as well as the mysterious, unseen “dark matter.” While earlier studies have shown holes, or voids, in the large-scale structure of the Universe, this new discovery dwarfs them all.
“Not only has no one ever found a void this big, but we never even expected to find one this size,” said Lawrence Rudnick of the University of Minnesota astronomy professor. Rudnick, along with grad student Shea Brown and associate professor Liliya Williams, also of the University of Minnesota, reported their findings in a paper accepted for publication in the Astrophysical Journal.
Astronomers have known for years that, on large scales, the Universe has voids largely empty of matter. However, most of these voids are much smaller than the one found by Rudnick and his colleagues. In addition, the number of discovered voids decreases as the size increases.
“What we’ve found is not normal, based on either observational studies or on computer simulations of the large-scale evolution of the Universe,” Williams said.
The astronomers drew their conclusion by studying data from the NRAO VLA Sky Survey (NVSS), a project that imaged the entire sky visible to the Very Large Array (VLA) radio telescope, part of the National Science Foundation's National Radio Astronomy Observatory (NRAO). Their study of the NVSS data showed a remarkable drop in the number of galaxies in a region of sky in the constellation Eridanus, southwest of Orion.
“We already knew there was something different about this spot in the sky,” Rudnick said. The region had been dubbed the “WMAP Cold Spot,” because it stood out in a map of the Cosmic Microwave Background (CMB) radiation made by the Wilkinson Microwave Anisotopy Probe (WMAP) satellite, launched by NASA in 2001. The CMB, faint radio waves that are the remnant radiation from the Big Bang, is the earliest “baby picture” available of the Universe. Irregularities in the CMB show structures that existed only a few hundred thousand years after the Big Bang.
The WMAP satellite measured temperature differences in the CMB that are only millionths of a degree. The cold region in Eridanus was discovered in 2004.
Astronomers wondered if the cold spot was intrinsic to the CMB, and thus indicated some structure in the very early Universe, or whether it could be caused by something more nearby through which the CMB had to pass on its way to Earth. Finding the dearth of galaxies in that region by studying NVSS data resolved that question.
“Although our surprising results need independent confirmation, the slightly lower temperature of the CMB in this region appears to be caused by a huge hole devoid of nearly all matter roughly 6-10 billion light-years from Earth,” Rudnick said.
How does a lack of matter cause a lower temperature in the Big Bang’s remnant radiation as seen from Earth"
The answer lies in dark energy, which became a dominant force in the Universe very recently, when the Universe was already three-quarters of the size it is today. Dark energy works opposite gravity and is speeding up the expansion of the Universe. Thanks to dark energy, CMB photons that pass through a large void just before arriving at Earth have less energy than those that pass through an area with a normal distribution of matter in the last leg of their journey.
In a simple expansion of the universe, without dark energy, photons approaching a large mass -- such as a supercluster of galaxies -- pick up energy from its gravity. As they pull away, the gravity saps their energy, and they wind up with the same energy as when they started.
But photons passing through matter-rich space when dark energy became dominant don't fall back to their original energy level. Dark energy counteracts the influence of gravity and so the large masses don’t sap as much energy from the photons as they pull away. Thus, these photons arrive at Earth with a slightly higher energy, or temperature, than they would in a dark energy-free Universe.
Conversely, photons passing through a large void experience a loss of energy. The acceleration of the Universe's expansion, and thus dark energy, were discovered less than a decade ago. The physical properties of dark energy are unknown, though it is by far the most abundant form of energy in the Universe today. Learning its nature is one of the most fundamental current problems in astrophysics.
Source: University of Minnesota
Explore further: Plasma-spewing quasar shines light on universe's youth, early galaxy formation | <urn:uuid:6cc2264f-59ee-4aa1-8044-9510f70e0e00> | 3.5 | 994 | News Article | Science & Tech. | 36.200363 | 95,556,100 |
As a result of an up to 5°C increase in water temperatures over the next few years, this pioneering study shows an increase in the regression rate of benthic primary producers, a deterioration in ecological status and the appearance of eutrophication processes in many coastal lagoons. Notable effects include the proliferation of jellyfish.
The work, recently published in the Estuarine Coastal and Shelf Science magazine and financed by the Euro-Mediterranean Institute of Water, represents the first data-based assessment of the vulnerability of the lagoon’s entire coastal ecosystem to a probable environmental change and eutrophication. According to the researchers, it is “essential” to know the interactions between the processes for identifying future impacts and establishing effective coastal planning and management measures.
“If climate change predictions come true, the current state of the Mar Menor lagoon could collapse due to proliferations of phytoplankton and floating macroalgae”, Javier Lloret, one of the study's researchers, explained to SINC. He talked about a profound deterioration of the entire ecosystem “through the appearance of eutrophication processes with high concentrations of nutrients”.
The research, applicable to other lagoons, forecasts that the global climate will have a “high” effect on coastal lagoons, which are considered “one of the most fragile marine environments to these changes”, Lloret pointed out. Among the most harmful effects, scientists highlight the increase in water temperature, a rise in sea level of at least a 50 cm, changes in the hydrodynamism of water masses and in the water’s salinity, as well as an increase in dissolved carbon dioxide, frequency of extreme climatic events and appearance of eutrophication processes.
Proliferation of jellyfish due to climate change
One of the main consequences of an increase in lagoon temperatures is the proliferation of jellyfish, which represent “an example of the alteration of the system’s trophic state and instability of parameters for the lagoon”, indicated the researcher from the Ecology and Hydrology Department at the University of Murcia.
In addition, the study highlighted that a loss of benthic macrophytes and appearance of eutrophication processes could result in “a substantial decrease in the quality of the lagoon’s habitat with unforeseen consequences for the biological diversity of its communities”. To this is added the possible reduction in the amount of light reaching the beds of the Mar Menor lagoon due to the proliferation of phytoplankton.
“This reduction is the result of the combined effect of the rise in sea level and decrease in the transparency of the water column caused by an increase in the entry of nutrients and dissolved solids”, Lloret added. The biomass of the Caulerpa prolifera macroalgae, which covers 91.7% of the lagoon's beds and is below 5 metres in depth, is responsible for maintaining a positive carbon balance. However, most of this biomass would be affected, even with death, due to a reduction in photosynthesis with an increase of water temperature over 30ºC.
The Mar Menor lagoon has ecological characteristics of high productivity and biological diversity as a result of being separated from the Mediterranean Sea by a 22 km long, 100 m to 1,200 m wide sand bar. Designated by the United Nations as a ‘Specially Protected Area of Mediterranean Importance’, the coastal lagoon is, however, vulnerable to eutrophication due to the rise in population along the coast and use of fertilisers for agriculture.
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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Physical Applications of Vector Calculus
T his chapter represents the culmination of multivariable calculus. We investigate the remarkable physical applications of vector calculus that provided the original motivation for the development of this subject in the seventeenth, eighteenth, and nineteenth centuries. The vector fields that we examine arise naturally in celestial mechanics, electromagnetism, and fluid flow. We will use the basic concepts of vector calculus to derive fundamental laws of physics in these subjects. In the attached Problem Set I, you will have a chance to use Mathematica to solve some interesting physical problems that would be difficult or impossible to tackle with pencil and paper alone.
KeywordsVector Field Gravitational Field Incompressible Fluid Flow Vector Calculus Newtonian Gravitation
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From how massive humpbacks glide through the sea with ease to the efficient way fungal spores fly, applied mathematicians at Harvard have excavated the equations behind a variety of complex phenomena.
The latest numerical feat by Otger Campàs and Michael Brenner, working closely with a team of Harvard evolutionary biologists led by Arhat Abzhanov, zeroes in on perhaps the most famous icon of evolution: the beaks of Darwin's finches.
In a study appearing in the February 16 Early Edition of the Proceedings of the National Academy of Sciences (PNAS), the researchers demonstrate that simple changes in beak length and depth can explain the important morphological diversity of all beak shapes within the famous genus Geospiza.
Broadly, the work suggests that a few, simple mathematical rules may be responsible for complicated biological adaptations.
The investigation began at Harvard's Museum of Comparative Zoology, where Campàs, a postdoctoral fellow at the Harvard School of Engineering and Applied Sciences (SEAS), and Ricardo Mallarino, a graduate student in the Department of Organismic and Evolutionary Biology (OEB) at Harvard, obtained photographs of beak profiles from specimens of Darwin's finches.
Using digitization techniques, the researchers found that 14 distinct beak shapes, that at first glance look unrelated, could be categorized into three broader, group shapes. Despite the striking variety of sizes and shapes, mathematically, the beaks within a particular group only differ by their scales.
"It is not possible, however, to explain the full diversity of beak shapes of all Darwin's finches with only changes in beak length and depth," explains Campàs. "By combining shear transformations (basically, what happens when you transform a square into a rhombus by shoving the sides toward one another), with changes in length and depth, we can then collapse all beak shapes onto a common shape."
Using Micro-Computed Tomography (CT) scans on the heads for the different species in the genus Geospiza, Anthony Herrel, an Associate of the Museum of Comparative Zoology, helped the team go one step further, verifying that the bone structure of the birds exhibits a similar scaling pattern as the beaks.
Thus, beak shape variation seems to be constrained by only three parameters: the depth of the length for the scaling transformation and the degree of shear.
Brenner, Glover Professor of Applied Mathematics at SEAS, says he is "astonished" that so few variables can help explain such great diversity. The mechanism that allows organisms to adapt so readily to new environments may be a relatively "easy" process.
"This is really significant because it means that adaptive changes in phenotype can be explained by modifications in a few simple parameters," adds Mallarino. "These results have encouraged us to try to find the remaining molecules responsible for causing these changes."
In fact, the mathematical findings also have a parallel genetic basis. Abzhanov, an assistant professor in OEB, and his collaborators explored the role of the two genes responsible for controlling beak shape variation. Bmp4 expression affects width and depth and Calmodulin expression relates to length. It turns out that the expression levels of the two genes, in particular Bmp4, are fundamentally related to the scaling transformations.
"We wanted to know how beaks changed on a fundamental level during evolution of Darwin's finches and how many unique beak shapes we need yet to explain using our developmental genetics approach," says Abzhanov. "Our joint study demonstrates that we understand the species-level variation really well where scaling transformations match up perfectly with expression and function of developmental genes which regulate precisely such type of change. Now we want to understand how novel beak shapes resulting from higher order transformations evolved in Darwin's finches and beyond."
Campàs reflects that the finding helps to address an idea that Darwin raised nearly 175 years ago in the Voyage of the Beagle: "The most curious fact is the perfect gradation in the size of the beaks in the different species of Geospiza, from one as large as that of a hawfinch to that of a chaffinch, and even to that of a warbler … Seeing this gradation and diversity of structure in one small, intimately related group of birds, one might really fancy that from an original paucity of birds in this archipelago [Galapagos], one species had been taken and modified for different ends."
The researchers acknowledge the support of the National Science Foundation through the Division of Mathematical Sciences, and the Materials Research Science and Engineering Center, both at Harvard; the Kavli Institute for Bionano Science and Technology at Harvard University; and the National Institutes of Health.
Michael Patrick Rutter | EurekAlert!
Innovative genetic tests for children with developmental disorders and epilepsy
11.07.2018 | Christian-Albrechts-Universität zu Kiel
Oxygen loss in the coastal Baltic Sea is “unprecedentedly severe”
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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...
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- Research news
- Open Access
© BioMed Central Ltd 2002
Published: 22 February 2002
A whole menagerie of animals (including sheep, mice, cattle, goats and pigs) have been cloned by transfer of nuclear genetic material into an enucleated cell. Now, in an Advanced Online Publication from Nature, Shin et al. demonstrate that cats (Felis domesticus) can be cloned too (14 February 2002, DOI: 10.1038/nature723). They isolated fibroblasts from the oral mucosa of an adult male cat or primary cumulus cell cultures and fused them with enucleated cat ova; they then implanted cloned embryos into a recipient mother. One kitten was delivered by caesarian section just before Christmas 2001, 66 days after embryo transfer. Analysis of seven unlinked, polymorphic, cat-specific microsatellite loci confirmed that the kitten really is a clone. The cloned kitten's coat colour patterning is not identical to the donor's, demonstrating the influence of non-genetic developmental factors. Now that they can be cloned, cats may prove to have many more than nine lives.
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(L.) Th.Fr (1860)
Xanthoria parietina is a foliose, or leafy, lichen. It has wide distribution, and many common names such as common orange lichen, yellow scale, maritime sunburst lichen and shore lichen. It can be found near the shore on rocks or walls (hence the epithet parietina meaning "on walls"), and also on inland rocks, walls, or tree bark. It was chosen as a model organism for genomic sequencing (planned in 2006) by the US Department of Energy Joint Genome Institute (JGI).
The species was first described by Carl Linnaeus in 1753, as Lichen parietinus.
The vegetative body of the lichen, the thallus, is foliose, and typically less than 8 centimetres (3.1 in) wide. The lobes of the thallus are 1–4 mm in diameter, and flattened down. The upper surface is some shade of yellow, orange, or greenish yellow, while the lower surface is white, with a cortex, and with sparse pale rhizines or hapters. The vegetative reproductive structures soredia and isidia are absent in this species, however, apothecia are usually present.
The outer "skin" of the lichen, the cortex, is composed of closely packed fungal hyphae and serves to protect the thallus from water loss due to evaporation as well as harmful effects of high levels of irradiation. In Xanthoria parietina, the thickness of the thalli is known to vary depending on the habitat in which it grows. Thalli are much thinner in shady locations than in those exposed to full sunshine; this has the effect of protecting the algae that cannot tolerate high light intensities. The lichen pigment parietin gives this species a deep yellow or orange-red color.
The photosynthetic symbionts, or photobionts, associated with X. parietina are from the green algal genus Trebouxia. Species that have been found include Trebouxia arboricola and T. irregularis. Both of these photobionts are known to occur free-living in nature, having been found on bark colonized by X. parietina as well as on bark not colonized by lichens.
In one study, the photobiont was shown to occupy 7% of the volume of the thallus. The density of pigmentation of the upper cortex also varies and seems to control the amount of light reaching the algae.
Reproduction and dispersal
A large number of lichens disperse very effectively by means of symbiotic vegetative propagules such as soredia, isidia and blastidia, and thallus fragmentation. However, X. parietina does not produce the vegetative propagules, but has to establish the symbiotic state at each reproductive cycle. It has been demonstrated that two oribatid mite species, Trhypochtonius tectorum and Trichoribates trimaculatus, common inhabitants and consumers of X. parietina, are vectors of the photobiont cells. Faecal pellets of both species contain both viable ascospores and photobiont cells, and are suggested to be a common mode of vegetative short- and long-distance dispersal of this species.
Habitat and distribution
Hardwood forests in low-elevation broad valleys; scattered on Populus and other hardwoods in riparian areas in agricultural and populated areas. It is often associated with high level of nitrogen and favored by eutrophication and can be often found near farmland and around livestock.
X. parietina is a widespread lichen, and has been reported from Australia, Africa, Asia, North America and throughout much of Europe. In eastern North America and Europe, it is found more frequently near coastal locations. The increases in nitrate deposition as a result of industrial and agricultural developments in southern Ontario, Canada in the 20th century are thought to be responsible for the reappearance of this species in the local lichen flora.
Xanthoria parietina is a very pollution-tolerant species. In laboratory experiments, this species can tolerate exposure to air contaminants and bisulphite ions with little or no damaging effect. It is also tolerant of heavy metal contamination.
X. parietina produces an orange colored anthraquinone pigment, parietin, that gets deposited as tiny crystals in the top layer of the upper cortex. Parietin synthesis is enhanced by UV-B, and stimulated by photosynthates, such as those provided by the green algal Trebouxia symbiont. X. parietina also produces the metabolite 2-methoxy-4,5,7-trihydroxy-anthraquinone.
The water extract of X. parietina has good antiviral activity in vitro, inhibiting the replication of human parainfluenza virus type 2. In the past it was used as a remedy for jaundice because of its yellow color.
- Geiser, Linda; McCune, Bruce (1997). Macrolichens of the Pacific Northwest. Corvallis: Oregon State University Press. p. 321. ISBN 0-87071-394-9.
- Galun, Margalith (1988). CRC Handbook of Lichenology, Volume I. Boca Raton: CRC. p. 105. ISBN 0-8493-3581-7.
- Armstrong RQ. (1984). "The influence of bird droppings and uric acid on the growth of five species of saxicolous lichens." Environmental and Experimental Botany 24: 95.
- Ahmadjian, Vernon. (1993). The lichen symbiosis. New York: John Wiley. pp. 32–33. ISBN 0-471-57885-1.
- Bubrick P, Galun M, Frensdorff A. (1984). "Observations on free-livingTrebouxia de Puymaly and Pseudotrebouxia Archibald, and evidence that both symbionts from Xanthoria parietina (L.) Th. Fr. can be found free-living in nature." New Phytologist 97: 455.
- Biology of Lichens. Cambridge, UK: Cambridge University Press. 1983. p. 51. ISBN 0-7131-2457-1.
- Meier FA, Scherrer S, Honegger R. (2002). "Faecal pellets of lichenivorous mites contain viable cells of the lichen-forming ascomycete Xanthoria parietina and its green algal photobiont, Trebouxia arbicola." Biological Journal of the Linnean Society76(2): 259–268.
- Gaio-Oliveira G, Dahlman L, Palmqvist K, Máguas C. (2004). "Ammonium uptake in the nitrophytic lichen Xanthoria parietina and its effects on vitality and balance between symbionts."Lichenologist 36: 75–86.
- Van Herk CM. (1999). "Mapping of ammonia pollution with epiphytic lichens in The Netherlands." Lichenologist 31:9–20.
- Frati L, Santoni S, Nicolardi V, Gaggi C, Brunialti G, Guttova A, Gaudino S, Pati A, Pirintsos SA, Loppi S. (2007). Lichen biomonitoring of ammonia emission and nitrogen deposition around a pig stockfarm. Environmental Pollution 146: 311&ndsash;6.
- Hogan, C. Michael. 2008. Black Spruce: Picea mariana, GlobalTwitcher.com, ed. Nicklas Stromberg Archived October 5, 2011, at the Wayback Machine.
- Lindblom L. (1997). "The genus Xanthoria (Fr.) Th. Fr. in North America." Journal of the Hattori Botanical Laboratory 83:75–172.
- Brodo IM, Lewis C, Craig B. (2007). "Xanthoria parietina, a coastal lichen, rediscovered in Ontario." Northeastern Naturalist 14(2): 300–6.
- Silberstein L, Siegel BZ, Sigel SM, Mukhtar A, Galun M. (1996). Comparative studies on Xanthoria parietina, a pollution-resistant lichen and Ramalina duriaei, a sensitive species. I. Effects of air pollution of physiologocal processes." Lichenologist 28(4): 355–65.
- Bačkor M, Fahselt D, Davidson R, Wu CT. (2003). "Effects of copper on wild and tolerant strains of the lichen photobiont Trebouxia erici (Chlorophyta) and possible tolerance mechanisms." Archives of Environmental Contamination and Toxicology 45: 159–67.
- Brunialti G, Frati L. (2007). Biomonitoring of nine elements by the lichen Xanthoria parietina in Adriatic Italy: A retrospective study over a 7-year time span.Science of the Total Environment 387(1–3): 289-300.
- Loppi S, Paoli L, Gaggi C. 2006). "Diversity of epiphytic lichens and Hg contents of Xanthoria parietina Thalli as monitors of geothermal air pollution in the Mt. Amiata area (Central Italy)."Journal of Atmospheric Chemistry 53(2): 93–105.
- Solhaug KA, Gauslaa Y, Nybakken L, Bilger W. (2003). "UV-induction of sun-screening pigments in lichens." New Phytologist 158:91–100.
- Solhaug KA, Gauslaa Y. (2004). "Photosynthates stimulate the UV-B induced fungal anthraquinone synthesis in the foliose lichen Xanthoria parietina." Plant Cell and Environment 27: 167–76.
- Ivanova V, Schlegel R, Gräfe U (October 2000). "2-Methoxy-4,5,7-trihydroxy-anthraquinone, a new lichen metabolite produced by Xanthoria parietina". Pharmazie. 55 (10): 785–6. PMID 11082848.
- Karagoz A, Aslan A. (2005). Antiviral and cytotoxic activity of some lichen extracts. Biologia 60(3): 281–6.
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A multidisciplinary Eurofins team in the Eurofins flagship Genomics laboratory in Ebersberg, Germany, has successfully completed a research project to genetically discriminate "identical" monozygotic twins.
So far there have been only theoretical considerations against the experimental finding and dogma that monozygotic twins are genetically fully identical. Statistically, around 6 of 1,000 males are identical twins. Up to now, forensic DNA fingerprinting testing could not be used in crime or paternity cases involving identical twins, as there was no possibility of genetically discriminating between them. Such cases are regularly discussed in the World's press, including murder, child custody and heritage cases.
Forensic laboratories around the world had accepted these analytical restrictions, but Eurofins scientists wanted to push these limits of DNA testing. They used the unique combination of leading forensics and genomics labs available at Eurofins to reach this milestone.
Technically, the Eurofins scientists applied Eurofins' ultra-deep next generation sequencing and associated bioinformatics techniques. They sequenced DNA from sperm samples of two twins and from a blood sample of the child of one twin. Bioinformatics analysis revealed five mutations, so called Single Nucleotide Polymorphisms (SNPs) present in the twin father and the child, but not in the twin uncle. The SNPs were confirmed by classical Sanger sequencing. The results give experimental evidence for the hypothesis that rare mutations will occur early after or before the human blastocyst has split into two, the origin of twins, and that such mutations will be carried on into somatic tissue and the germ line.
The genetic differences found and the method used provide a solution to solve forensic and paternity cases involving monozygotic twins as originator of DNA traces in crime, or as alleged fathers. Eurofins is the first to offer such a test.
The peer-reviewed study "Finding the needle in the haystack: Differentiating "identical" twins in paternity testing and forensics by ultra-deep next generation sequencing" is published in the renowned journal Forensic Science International: Genetics, Available online 8 November 2013, ISSN 1872-4973, http://dx.doi.org/10.1016/j.fsigen.2013.10.015.
Bruno Poddevin, Senior Vice-President of the Genomic Services division and head of the Forensics laboratory at Eurofins, comments: "Eurofins scientists are the first to proof that monozygotic twins are genetically not absolutely identical. As the only provider worldwide Eurofins can now offer DNA forensic and paternity testing to discriminate identical twins to authorities, courts and individuals. Our leading genomic and forensic services team has provided the basis for reaching this milestone. As the first provider of next generation sequencing services in Europe, Eurofins also has proprietary, long expertise in the professional handling and analysis of the enormous amount of data involved in such a project. The dataset in this project equaled a total of 241 human genomes, resulting from up to 94 fold genomic coverage of the involved three individuals.
The Eurofins "Twin Test" is available at all laboratories of the Eurofins Genomics and Eurofins Genetics Division. The test will be performed at the Eurofins DNA Campus in Ebersberg, at the laboratories of Eurofins MWG Operon and Eurofins Forensics.
Dr. Georg Gradl | 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...
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Spider silk is an impressive material: Light weight and stretchy yet stronger than steel. Silk proteins, called spidroins, rapidly convert from a soluble form to solid fibers at ambient temperatures and with water as solvent. How the spiders regulate this process is to a large extent unknown.
Now, Anna Rising and Jan Johansson at the Swedish University of Agricultural Sciences (SLU) and Karolinska Institutet show how the silk formation process is regulated. The work was done in collaboration with colleagues in Latvia, China and USA.
Spidroins are big proteins of up to 3,500 amino acids that contain mostly repetitive sequences. The non-repetitive N- and C-terminal domains at opposite ends are thought to regulate conversion to silk. These terminal domains are unique to spider silk and are highly conserved among spiders.
Spidroins have a helical and unordered structure when stored as soluble proteins in silk glands, but when converted to silk they contain β-sheets that confer mechanical stability. We know that there is a pH gradient across the spider silk gland, which narrows from a tail to a sac to a slender duct, and that silk forms at a precise site in the duct. But further details of spider silk production have been elusive.
By using ion-selective microelectrodes to measure the pH of the glands we could show that the pH fall from 7.6 to 5.7 between the beginning of the tail and half-way down the duct. This pH gradient is much steeper than previously thought.
The microelectrodes also showed that bicarbonate ions and carbon dioxide pressure simultaneously rise along the gland. Taken together, these patterns suggested that the pH gradient is due to carbonic anhydrase, an enzyme that converts carbon dioxide and water to bicarbonate and hydrogen ions. We used a histological method, developed at SLU, to identify active carbonic anhydrase in the distal part of the gland. Carbonic anhydrase is responsible for generating the pH gradient since an inhibitor called methazolamide collapsed the pH gradient.
We also found that pH had opposite effects on the two domains' stability, which was a surprise given that the domains had been suggested to have a similar impact on silk formation. The N-terminal dimerized at pH 6 (i.e. in the beginning of the duct) and became increasingly stable as the pH dropped along the duct.
In contrast, the C-terminal domain destabilized as the pH dropped, gradually unfolding until it formed the β-sheets characteristic of silk at pH 5.5. These findings show that both terminals undergo structural changes at the pH found in the beginning of the duct. Importantly, this is also where carbonic anhydrase activity is concentrated.
These findings led us to propose a new "lock and trigger" model for spider silk formation. Gradual dimerization of the N-terminal domains lock spidroins into multimers, while the β-sheet fibrils at the C-terminals could serve as nuclei that trigger rapid polymerization of spidroins into fibers. Interestingly, the C-terminal β-sheets are similar to those in the amyloid fibrils characteristic of diseases such as Alzheimer's disease. This mechanism elegantly explains how spider silk
can form so quickly as well as how its formation can be confined to the spinning duct. Besides being essential to producing biomimetic spidroin fibers, knowing how spiders spin silk could give insights into natural ways of hindering the amyloid fibrils associated with disease.
Anna Rising, Researcher SLU and KI, ph +46-70 974 48 88 firstname.lastname@example.org
Jan Johansson, Professor, SLU and KI, +46-70-34 570 48
SLU:s vision: SLU är ett universitet i världsklass inom livs- och miljövetenskaper.
David Stephansson | www.mynewsdesk.com
Metal too 'gummy' to cut? Draw on it with a Sharpie or glue stick, science says
19.07.2018 | Purdue University
Machine-learning predicted a superhard and high-energy-density tungsten nitride
18.07.2018 | Science China Press
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
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Scientists at Johns Hopkins are calling for simultaneous evaluation of both genetic and epigenetic information in the search to understand contributors to such common diseases as cancer, heart disease and diabetes. Writing in the August issue of Trends in Genetics, available now online, the scientists provide a framework for systematically incorporating epigenetic information into traditional genetic studies, something they say will be necessary to understand the genetic and environmental factors behind common diseases. "Epigenetics doesnt underlie all human disease, but we definitely need to develop the technology to figure out when and where epigenetic changes do influence health and disease," says Andrew Feinberg, M.D., King Fahd Professor of Medicine.
Much as the genetic sequence is passed from parent to child, epigenetic "marks" that sit on our genes are also inherited. These "marks," usually small methyl groups, are attached to genes backbones and convey information, such as identifying which parent the gene came from. The marks also normally turn genes on or off. But just as changes in DNA sequences can cause diseases such as cancer, gain or loss of epigenetic marks can, too.
To date, only small, targeted regions of DNA have been analyzed for accompanying epigenetic marks. But the Hopkins researchers say now is the time to begin studying epigenetics on the same mammoth scale used to probe the sequence of creatures genetic building blocks.
Joanna Downer | EurekAlert!
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
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
19.07.2018 | Materials Sciences | <urn:uuid:f52bfed8-554d-4188-a6a1-32853e36ec0e> | 3.328125 | 924 | Content Listing | Science & Tech. | 35.699814 | 95,556,257 |
Freeway Traffic. According to a Scientific American article (May, 1990), current freeways can sustain about N vehicles per lane per hour in smooth traffic flow at speed . Above that figure the traffic flow becomes "turbulent" (stop-and-go).
1) If a vehicle is of length L on the average, what is the average spacing between vehicles at the above traffic density?
2) Collision-avoidance automated control systems, which operate by bouncing radar or sonar signals off surrounding vehicles and then accelerate or brake the car when necessary, could greatly reduce the required spacing between vehicles. If the average spacing is a distance x (two car lengths), how many vehicles per hour can a lane of traffic carry at speed v?© BrainMass Inc. brainmass.com July 23, 2018, 12:22 am ad1c9bdddf | <urn:uuid:26328dd5-cced-48e9-ac95-d5f241433da1> | 3.53125 | 176 | Tutorial | Science & Tech. | 49.429642 | 95,556,307 |
Species Curinus coeruleus - Metallic Blue Lady Beetle
The Coccinellidae (Coleoptera) of America North of Mexico By Robert D. Gordon
Journal of the New York Entomological Society, Vol. 93, No. 1, 1985
Slightly dated with regard to status of imported species (1985 - Harmonia axyridis establishment listed as questionable - oh, were it true!), but still a great comprehensive work covering all of lower 48, with detailed line drawings, keys to all species, and distribution maps.
Full text on-line
Nutritional aspects of non-prey foods in the life histories of predaceous Coccinellidae.By Lundgren, J.G.
Biological Control 51(2): 294–305., 2009
Lundgren, J.G. 2009. Nutritional aspects of non-prey foods in the life histories of predaceous Coccinellidae. Biological Control 51(2): 294–305.
Non-prey foods are an integral component of the diets of most predaceous coccinellids. Under field conditions, numerous coccinellids consume nectar, honeydew, pollen, fruit, vegetation
, and fungus
. These non-prey foods are used by coccinellids to increase survival when prey is scarce, reduce mortality during diapause, fuel migration, and enhance reproductive capacity.
Ecology and behaviour of the ladybird beetles (Coccinellidae).By Hodek, I., H.F. van Emden & A. Honěk (eds).
Blackwell Publishing Ltd., Chichester, UK, xxxvii + 561 pp., 2012
Hodek, I., H.F. van Emden & A. Honěk (eds). 2012. Ecology and behaviour of the ladybird beetles (Coccinellidae). Blackwell Publishing Ltd., Chichester, UK, xxxvii + 561 pp.
from publisher's website
Ladybirds are probably the best known predators of aphids and coccids in the world, though this greatly underestimates the diversity of their biology. Maximising their impact on their prey is an important element in modern conservation biological control of indigenous natural enemies in contrast to the classical approach of releasing alien species.
Causes and consequences of ladybug washups in the Finger Lakes region of New York State (Coleoptera: Coccinellidae).By Denemark, E. and J. Losey.
Entomologica Americana, 116: 78-88., 2010
Download Full PDF
Denemark, E. and J. Losey. 2010. Causes and consequences of ladybug washups in the Finger Lakes region of New York State (Coleoptera: Coccinellidae). Entomologica Americana, 116: 78-88.
Abstract.—We searched for and collected data on a phenomenon known as ladybug washups, in which large numbers of coccinellids aggregate on the shores of major bodies of water. Our field season lasted from 5/23/2008 until 8/12/2008 in the Finger Lakes Region of New York, United States.
Aggregation of lady beetles on the shores of lakes (Coleoptera: Coccinellidae).By Lee, R.E., Jr.
American Midland Naturalist, 104(2): 295-304., 1980
Lee, R.E., Jr. 1980. Aggregation of lady beetles on the shores of lakes (Coleoptera: Coccinellidae). American Midland Naturalist, 104(2): 295-304.
ABSTRACT: Aggregations of lady beetles, predominately Hippodamia convergens
and H. tredecimpunctata
, were commonly observed on the shores of lakes in the Upper Midwest during the autumn and spring. The beetles remain on the shore for only a short time, usually dispersing within 2-3 weeks. Lady beetles from autumn shore aggregations and overwintering aggregations are characterized by the presence of large amounts of fat, reproductive inactivitiy, empty digestive tracts, a skew in the sex ratio favoring females and the behavioral tendency to form aggregations.
The Coccinellidae of Louisiana (Insecta: Coleoptera).By Chapin, J.B.
Louisiana Agricultural Experiment Station Bulletin 682: 2-87., 1974
- I have inserted, as page 2, an undated taxonomic addendum compiled by Chapin.
Chapin, J.B. 1974. The Coccinellidae of Louisiana (Insecta: Coleoptera). Louisiana Agricultural Experiment Station Bulletin 682: 2-87.
Dr. Joan Beggs Chapin (1929-2014)
A taxonomic study of the Coccinellidae of Louisiana was undertaken in 1965 to identify the species occurring in the state. Keys and descriptions are provided for the 6 subfamilies, 11 tribes, 27 genera, and 71 species recorded
as occurring in the state. Of the species listed, 38 are reported as new. Distribution records by parish and dates of seasonal occurrences are given. | <urn:uuid:ef58cc0d-dcd4-4a56-8a4b-580684e6b322> | 2.96875 | 1,077 | Content Listing | Science & Tech. | 47.420865 | 95,556,318 |
China is building a global big data network to study Earth and support research on climate change, as well as predict and mitigate natural disasters, scientists said on Monday.
The project will include more than 1,200 scientists at 130 institutions worldwide and cover more than a dozen subjects, ranging from oceanology to meteorology, according to Guo Huadong, who is leading the project for the Chinese Academy of Sciences.
He said the network will be the centerpiece of CAS Earth, a five-year, 1.76 billion yuan ($279 million) project to create a robust international environmental research network that will serve scientists and officials in China as well as countries and regions involved in the Belt and Road Initiative.
"Big data has opened a new window for Earth-related studies, and it is key for scientists to unlock the secrets and understand our planet," Guo said.
Such information has become a strategic resource for countries, alongside natural and human resources, he added.
Chinese scientists have collected massive Earth science data over the decades, according to Bai Chunli, the academy's president.
Guo said the academy has about 44 petabytes－46 million gigabytes－of data, although it is relatively lacking in marine data, especially on far seas.
Around four years ago, the United States had about 30 percent of all the data in the world, more than any other country, while China ranked third with 16 percent, he said. By 2020, China aims to have 21 percent of the world's data.
"Chinese leaders place heavy emphasis on big data because it is invaluable to innovation and the digital economy," he said. "Big data has become a key indicator of a country's science and development level."
China has also launched many Earth observation satellites in recent years, such as the Fengyun 3D in November and TANSAT－the country's first carbon dioxide monitoring satellite－in 2016.
"These new tools will collect valuable data to serve researchers worldwide," Bai said.
However, although industries such as finance and real estate have already incorporated big data into their operations, Guo said academia has struggled to keep up due to shortages in resources and research methods, inaccurate data, and a lack of data-sharing mechanisms between institutions and countries.
"The new network aims to overcome these issues by creating an interdisciplinary research platform open to the world," he said. "It will not only support China's goal of building a sustainable and green society, but also help other countries better understand and protect their environment, and maintain ecological security."
On Monday, the academy and publisher Taylor & Francis Group released the first volume of Big Earth Data, the first international science journal dedicated to studying Earth using big data.
Lyndsey Dixon, the publisher's editorial director for Asia-Pacific, said the new network and the journal "are extremely interesting and ambitious projects that use new discoveries and knowledge from big data to understand and protect the Earth". | <urn:uuid:bd2870f8-ebe4-4ab0-969c-776ef7096d49> | 3.21875 | 605 | News Article | Science & Tech. | 30.610379 | 95,556,324 |
Ceres' bright spots have been a winking mystery for months, but NASA finally thinks it's solved the riddle: No, we're not looking at a giant alien ice rink. More likely, enormous piles of salt.
"We believe this is a huge salt deposit," principal investigator for the Dawn spacecraft Chris Russell told scientists on Monday at the European Planetary Science Congress. "We know it's not ice and we're pretty sure it's salt, but we don't know exactly what salt at the present time."
As NASA's Dawn spacecraft continues its spiral toward dwarf planet Ceres, we're discovering a world filled with geologic complexity and strange, glimmering spots. The largest of the spots — a roughly six-mile wide patch in the ominously-named Occator Crater — was visible from afar, but now, we're close enough to see that the brightness is everywhere. Even some of Ceres' mountains are smeared with shiny streaks.
A yet-to-be-named mountain also bears the mysterious brightness. Image Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
Back in May, Russell speculated that the spots are caused by "the reflection of sunlight by highly reflective material on the surface, possibly ice." While the ice hypothesis fits with another theory — that Ceres might be hiding a subsurface ocean — Russell acknowledged that further studies were needed in order to verify the spots' composition.
Now, as Russell explained in his recent talk, data on the reflectivity of the bright spots has ruled out water ice. Based on the spots' albedo, we're pretty sure Ceres is encrusted in salt.
"[Salt] tells me that this is an active surface," Russell said. "Some comet or asteroid did not come in carrying salt, this is derived from the interior somehow."
As for how or why Ceres is oozing salt? That's another science mystery for you! For the next two months, Dawn will continue its descent, taking even closer shots of Ceres and continuing to collect scientific data in order to unravel the mystery of the now-probably-salt-piles. Sit tight Earthlings, the answers are coming!
Top : The Occator Crater, colour-coded to show differences in elevation, via NASA/JPL-Caltech/UCLA/MPS/DLR/IDA | <urn:uuid:9c81f8b1-d2b8-4d05-ae4b-1d65ce4c8345> | 3.078125 | 489 | News Article | Science & Tech. | 48.553273 | 95,556,338 |
A new study from the University of Eastern Finland presents, for the first time, the isotopic fingerprint of nitrous oxide produced by Arctic soils. The finding opens new avenues for predicting future trends in atmospheric nitrous oxide as well as in identifying climate change mitigation actions in the Arctic, a region that is particularly sensitive to climate change.
Nitrous oxide (N2O) is a powerful greenhouse gas and also the second largest contributor to ozone depletion in the stratosphere. It is produced naturally by soils, with agricultural and tropical rain forest soils being the main sources of N2O to the atmosphere. Until recently, scientists assumed that nitrous oxide emissions were negligible in colder climate regions like the Arctic and sub-Arctic.
This assumption, however, was contradicted by scientists from the University of Eastern Finland a decade ago, when they discovered that bare peat surfaces in permafrost peatlands are releasing high amounts of N2O, despite the general nitrogen limitation of tundra ecosystems. Since then, N2O emissions and their underlying processes have been the object of plenty of research and, also, debate.
In a new study, researchers from the University of Eastern Finland, together with colleagues from the Venezuelan Institute for Scientific Research (IVIC) and the University of California, Berkeley, explore the isotopic composition and potential sources of nitrous oxide emitted by soils in the sub-Arctic tundra. The study explores new frontiers in polar science, and the approach used establishes a legacy of data and methodologies that have the potential to link the Arctic ecosystem with the global N2O cycle.
In the study, the researchers examined nitrogen and oxygen isotopes in N2O samples collected from permafrost peatland sites in northwestern Russia. Using "site preference" analysis, the scientists also identified the specific isotopes occupying the two different nitrogen sites within the nitrous oxide molecule. The study presents for the first time the isotopic fingerprint of N2O produced by soils of Arctic tundra, thereby contributing to an understanding of N2O production mechanisms in this understudied environment.
Since different microbial processes leave distinct isotopic fingerprints on nitrous oxide, the researchers also hoped to figure out the relative amounts of nitrous oxide emitted by different nitrogen-processing microbes in the tundra soils. The results suggest that the N2O emissions from bare tundra peat soils might be due to nitrifier denitrification, a microbial process that transforms ammonia (NH4) into N2 in a series of steps, one of which produces nitrous oxide. However, in the study year N2O emissions were low compared to previous years, and the reasons for the high emissions are still unclear. The isotope data was not conclusive enough, and even the sophisticated site preference technique did not provide enough information to tease out the relative roles of different microbes.
Nonetheless, the findings are valuable because isotopic nitrous oxide data from the Arctic and sub-Arctic are extremely rare. The findings could aid predictions of future trends in atmospheric nitrous oxide and help to identify mitigation actions in the Arctic, a region that is particularly sensitive to climate change. In the future, enhanced N2O emissions from natural soil such as sub-Arctic tundra might mask the isotope effect caused by mitigation actions derived from agriculture.
The findings were reported in Global Biogeochemical Cycles, and the article is featured as a Research Spotlight in the Eos magazine at https:/
For further information, please contact:
Researcher Jenie Gil, University of Eastern Finland, email: jenie.gillugo (a) uef.fi, tel. +358 40 3552111
Gil, J., T. Pérez, K. Boering, P. J. Martikainen, and C. Biasi (2017), Mechanisms responsible for high N2O emissions from subarctic permafrost peatlands studied via stable isotope techniques, Global Biogeochem. Cycles, 31, 172-189, doi:10.1002/2015GB005370.
Jenie Gil | 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
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This textbook presents a concise yet detailed introduction to quantum physics. Concise, because it condenses the essentials to a few principles. Detailed, because these few principles - necessarily rather abstract - are illustrated by several telling examples.Read more...
This textbook presents a concise yet detailed introduction to quantum physics. Concise, because it condenses the essentials to a few principles. Detailed, because these few principles - necessarily rather abstract - are illustrated by several telling examples. A fairly complete overview of the conventional quantum mechanics curriculum is the primary focus, but the huge field of statistical thermodynamics is covered as well.
The text explains why a few key discoveries shattered the prevailing broadly accepted classical view of physics. First, matter appears to consist of particles which, when propagating, resemble waves. Consequently, some observable properties cannot be measured simultaneously with arbitrary precision. Second, events with single particles are not determined, but are more or less probable. The essence of this is that the observable properties of a physical system are to be represented by non-commuting mathematical objects instead of real numbers.
Chapters on exceptionally simple, but highly instructive examples illustrate this abstract formulation of quantum physics. The simplest atoms, ions, and molecules are explained, describing their interaction with electromagnetic radiation as well as the scattering of particles. A short introduction to many particle physics with an outlook on quantum fields follows. There is a chapter on maximally mixed states of very large systems, that is statistical thermodynamics. The following chapter on the linear response to perturbations provides a link to the material equations of continuum physics. Mathematical details which would hinder the flow of the main text have been deferred to an appendix.
The book addresses university students of physics and related fields. It will attract graduate students and professionals in particular who wish to systematize or refresh their knowledge of quantum physics when studying specialized texts on solid state and materials physics, advancedoptics, and other modern fields.
This item is Non-Returnable.
- ISBN-13: 9783319585949
- ISBN-10: 3319585940
- Publisher: Springer
- Publish Date: September 2017
- Page Count: 368
- Dimensions: 9.21 x 6.14 x 0.88 inches
- Shipping Weight: 1.57 pounds
Series: Graduate Texts in Physics | <urn:uuid:6a0a5198-9d08-45c8-bc41-b114f5771c48> | 2.875 | 476 | Product Page | Science & Tech. | 28.855934 | 95,556,362 |
The research group of Alex Schier, Director of the Biozentrum, University of Basel, has investigated more closely how a single embryonic cell develops into a heart, nerve or blood cell. For the first time, the researchers have been able to reconstruct the developmental trajectories of individual embryonic cells. Their results also suggest that cells can change their path during their maturation process. The results of the study with around 40,000 cells have now been published in “Science”.
The origin of every cell of our body is a single cell, the fertilized egg. On the way to become a specialized cell, whether blood, heart or nerve cells, its descendants follow a genetic program. This program determines the identity of a cell, its features and function.
The research team led by Alex Schier, Director of the Biozentrum, University of Basel, and currently still research group leader at Harvard University in Cambridge, has now developed a new method that enables the scientists for the first time to trace the entire history of the differentiation of individual cells.
By combining the differentiation trajectories they have been able to construct a full developmental tree for embryogenesis. Furthermore, the team discovered that during differentiation, cells can leave their path and thus change their identity.
A widely branched tree for cell development
In their study, the team isolated around 40,000 cells and 25 different cell types that form in zebrafish over a period of nine hours. To investigate the maturation of these cells, they analyzed the RNA, a copy of the genetic material. “The RNA tells us, which genes are active and determines the function and characteristics of a cell”, says Schier.
In order to merge and compare the data, Schier’s team developed a new software (URD). While previous studies in this field are based on the examination of a handful of genes, the new high-throughput single-cell RNA sequencing method enables the analysis of all active genes during cell development. With this new technology, the team has been able to reconstruct, for the first time, a widely branched tree that traces the development of each individual cell, starting with the fertilized egg cell. In addition, they mapped the cells to their spatial origin in the early embryo.
Finding cell identity is more flexible than expected
The results show that the genetic program that a cell follows on the way to maturity is by no means set in stone. “It seems that the developmental path of a cell is more flexible than we previously expected”, says Alex Schier. So far, it was assumed that developing cells follow a predetermined path, like marbles rolling down a hill until they stop at their predestined place. The study now suggests that signals from the environment can have such a strong influence on the cells, that they leave the initial trajectory and change their path, thus taking on a new identity.
Entire development as a cell lineage tree
In a next step, the research group will expand the cell lineage tree, investigate more cell types and follow the development of cells over a longer period of time. “My aim is to merge the developmental trajectories and the lineage trees to one complete whole. If we can understand the logic behind cell differentiation, we may, one day, be able to answer the question: How many ways are there to build a heart or a brain?”
Jeffrey A. Farrell, Yiqun Wang, Samantha J. Riesenfeld, Karthik Shekhar, Aviv Regev and Alexander F. Schier
Single-cell reconstruction of developmental trajectoriesduring zebrafish embryogenesis
Heike Sacher, University of Basel, Biozentrum, Communications,
Tel. +41 61 207 14 49, Email: email@example.com
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Heike Sacher, University of Basel | Universität Basel
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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LOS ANGELES (AP) — In the ongoing quest to better anticipate future earthquakes, scientists embarked on an ambitious experiment: Identify the likeliest places where magnitude-4.9 quakes or stronger would occur in seismically active California over a five-year period.
Half a dozen teams decided to give it a shot. They developed sophisticated computer models, submitted their best guesses and waited. As part of the ground rules, they could not change their forecasts, which were checked against actual quakes that hit during the study period.
The goal was to see whether there was a reliable way to flag a seismic hotspot before the ground shakes.
The exercise, which began in 2006 and wrapped up last December, was not aimed at predicting quakes, which remains elusive. Instead, researchers were asked to pinpoint regions where quakes were more likely to occur based on past seismic history, activity on fault lines or other factors. The state was divided into 7,700 sections and teams had to give probabilities of quakes of varying magnitudes occurring in each one.
During the test period, 31 quakes larger than magnitude-4.9 rattled the state, including the greater Los Angeles region, San Francisco Bay area and off the Northern California coast. The largest was the 2010 Easter earthquake centered in Baja California that produced sizable aftershocks along the U.S.-Mexico border.
So how did scientists do?
“No single model takes home all the gold,” said seismologist John Vidale of the University of Washington who was not part of any team.
U.S. Geological Survey seismologist Sue Hough agreed. The experiment shows just “how difficult it is to even evaluate rigorously the success of prediction methods,” she said.
By one measure, three groups that took into account all past quakes regardless if they were big or small fared better than the rest. One of them analyzed the performance and published results online Monday in the Proceedings of the National Academy of Sciences
Some scientists questioned whether a team that has a stake in the game should be a referee. One of the study’s leaders, Donald Turcotte of the University of California, Davis, said it is unavoidable given the tight-knit earthquake science community.
“It is impossible to find people with expertise who are not participants in the experiment,” he said.
Jeremy Zechar of the University of Southern California, who is heading his own review, takes issue with the yardstick used by Turcotte’s team to gauge success. It was developed halfway into the experiment and was not part of the original criteria agreed to by the participants.
Seismologist David Jackson of the University of California, Los Angeles, likened the experiment to kiddie soccer.
There are “no official winners or losers, but plenty of scorekeeping from the sidelines” to learn the strengths and weaknesses of various quake theories, Jackson said. While scientists cannot say with certainty exactly when and where the next quake will strike, they have an idea of how quakes behave. For example, a big quake will produce smaller aftershocks in the same area. There’s still a lot that’s unknown such as whether quakes too small to be felt play a role in increasing the chances of a bigger quake.
Geophysicist John Ebel of Boston College was not surprised that his work ranked low in the study because he made simple assumptions.
“There’s still a lot we don’t understand,” Ebel said.
Since the California experiment ended, scientists are applying lessons learned to a similar international effort currently under way.
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Cold spell superimposes man-made warming
The Antarctic ice sheet is one of the tipping elements in the climate system and hence of vital importance for our planet’s future under man-made climate change. Even a partial melting of the enormous ice masses of Antarctica would raise sea-levels substantially.
Therefore it is of utmost importance to provide sound knowledge on the extent of anthropogenic warming of the ice-covered continent. A new analysis by German physicists shows that the uncertainties in the temperature trends over Antarctica are larger than previously estimated.
“So far it seemed there were hardly any major natural temperature fluctuations in Antarctica, so almost every rise in temperature was attributed to human influence,” says Armin Bunde of Justus-Liebig-Universität Gießen (JLU).
“Global warming as a result of our greenhouse gas emissions from burning fossil fuels is a fact. However, the human influence on the warming of West Antarctica is much smaller than previously thought. The warming of East Antarctica up to now can even be explained by natural variability alone.” The results of their study are now published in the journal Climate Dynamics.
The melting of Antarctic ice shelves is not only influenced by warming air but also by warming oceans, causing ice loss at the coast. However, as there are no sufficient long-term records for Antarctic ocean warming yet, the study focuses on air temperature trends.
In collaboration with Hans Joachim Schellnhuber of the Potsdam Institute for Climate Impact Research and Christian Franzke of the Cluster of Excellence "Integrated Climate System Analysis and Prediction" (CliSAP) of Hamburg University, the physicists of JLU Armin Bunde and Josef Luderer were able to show that there are major and very persistent temperature fluctuations in Antarctica.
“The climate in Antarctica, just like the global climate, tends to be distinctly persistent by nature – it remains in certain temperature ranges for a long time before it changes. This creates a temporal temperature structure of highs and lows,” explains Christian Franzke.
“A low, i.e. a longer cold period, will be followed by a longer warm period, and this natural warming has to be differentiated from the superimposed anthropogenic warming,” adds Armin Bunde. The scientists did not only analyze data from individual measuring stations but also generated regional averages. The results show a human influence on the warming of West Antarctica, while this influence is weaker than previously thought. However, the warming of Antarctica altogether will likely increase more strongly soon.
For several years temperatures in Antarctica, but also globally, have been increasing less rapidly than in the 1990s. There are a number of reasons for this, e.g. the oceans buffering warmth. The study now published by the German team of scientists shows that man-made global warming has not been pausing - it was temporarily superimposed and therefore hidden by long-term natural climate fluctuations like in Antarctica.
“Our estimates show that we are currently facing a natural cooling period – while temperatures nonetheless rise slowly but inexorably, due to our heating up the atmosphere by emitting greenhouse gas emissions,” explains Hans Joachim Schellnhuber. “At the end of this natural cold spell temperatures will rise even more fiercely. Globally, but also in Antarctica which therefore is in danger of tipping.” In fact, in March 2015 two Antarctic measuring stations registered high-temperature records.
Article: Ludescher, J., Bunde, A., Franzke, C., Schellnhuber, H.J. (2015): Long-term persistence enhances uncertainty about anthropogenic warming of West Antarctica. Climate Dynamics. [DOI: 10.1007/s00382-015-2582-5]
Link to the article: http://link.springer.com/article/10.1007/s00382-015-2582-5
For further information please contact:
PIK press office
Jonas Viering, Sarah Messina
Phone: +49 331 288 2507
Prof. Dr. Armin Bunde
Institut für Theoretische Physik der Justus-Liebig-Universität Gießen (JLU)
Phone: +49 641 99-33375
Mobile: +49 157 33 14 55 55
Caroline Kieke, Public Relations
Cluster of Excellence "Integrated Climate System Analysis and Prediction" (CliSAP)
of Hamburg University
Phone: +49 (0) 40 42838 2134
Jonas Viering | Potsdam-Institut für Klimafolgenforschung
Global study of world's beaches shows threat to protected areas
19.07.2018 | NASA/Goddard Space Flight Center
NSF-supported researchers to present new results on hurricanes and other extreme events
19.07.2018 | National Science Foundation
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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12.07.2018 | Event News
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|A shell of Epitonium scalare|
informal group Ptenoglossa
Berry, 1910 (1812)
P. F. Röding, 1798
|about 630 species|
The word wentletrap originated in Dutch (wenteltrap), and it means spiral staircase. These snails are sometimes also called "staircase shells", and "ladder shells".
The family Epitoniidae belongs to the superfamily Epitonioidea, which also includes the Janthinidae (the pelagic purple snails) and the family Nystiellidae, all part of the informal group Ptenoglossa. Epitoniidae is a rather large family, with an estimated number of species about 630.
Wentletraps inhabit all seas and oceans worldwide, from the tropical zones to the Arctic and Antarctic zones.
Most species of wentletrap are white, and have a porcelain-like appearance. They are notable for their intricately geometric shell architecture, and the shells of the larger species are prized by collectors.
The more or less turret-shaped shell consists of tightly-wound (sometimes loosely coiled), convex whorls, which create a high, conical spiral. Fine or microscopic spiral sculpture (also called "striae") is present in many species. The shells sometimes feature an umbilicus. Wentletrap shells have a roundish or oval aperture, but its inner lip is often reduced to strip of callus. The round and horny operculum is paucispiral and fits the aperture tightly. Most of the species in the family are small to minute, although some are larger, and overall the adult shell length in the family varies between 0.6 and 11.7 cm.
Within the genus Epitonium, the type genus of the family, the shell has predominantly axial sculpture of high, sharply ribbed "costae". These costae may offer some protection against other predatory snails, which would find it difficult or impossible to bore a hole in a shell with such obstructions.
Little is known about the biology of most wentletraps. Many wentletraps reveal a hint of purple body color, suggestive of carnivorous feeding (Keen, 1958). The animal can exude through its salivary gland a pink or purplish dye that may have an anaesthetic effect on its prey.
Keen also cited direct observation of a wentletrap feeding by insertion of its proboscis into a sea anemone. A sequence of a wentletrap feeding on an anemone has been published. These snails also prey on corals and other coelenterates.
Genera within the family Epitoniidae include:
- Acirsa Mörch, 1857
- Acrilloscala Sacco 1891
- Alexania Strand, 1928
- Alora (H. Adams, 1861)
- Amaea H. & A. Adams, 1853
- Boreoscala Kobelt, 1902 (possibly a synonym of Cirsotrema)
- Cerithiscala de Boury, 1887
- Chuniscala Thiele, 1928
- Cingulacirsa Higo & Goto, 1993
- Cirsotrema Mörch, 1852
- Claviscala de Boury, 1909
- Couthouyella Bartsch 1909
- Crebriscala de Boury, 1909
- Cycloscala Dall, 1889
- Cylindriscala de Boury, 1909
- Depressiscala de Boury 1909
- Ecclesiogyra Dall, 1892
- Eglisia Gray, 1842
- Epidendrium A. Gittenberger & E. Gittenberger, 2005
- Epifungium A. Gittenberger & E. Gittenberger, 2005
- Epitonium Röding, 1798
- Filiscala de Boury, 1911
- Foratiscala de Boury 1887
- Funiscala de Boury, 1890
- Globiscala de Boury, 1909
- Gregorioiscala Cossman, 1912
- Gyroscala de Boury, 1887
- Kurodacirsa Masahito & Habe, 1975
- Minabescala Nakayama, 1994
- Narvaliscala Iredale, 1936
- Opalia H. & A. Adams, 1853
- Periapta Bouchet & Waren, 1986
- Plastiscala Iredale, 1936
- Problitora Iredale, 1931
- Punctiscala Philippi, 1844
- Rutelliscala Kilburn, 1985
- Sthenorhytis Conrad 1862
- Surrepifungium A. Gittenberger & E. Gittenberger, 2005
- † Turriscala de Boury, 1890 †
- Variciscala de Boury, 1909
- Varicopalia Kuroda MS, 1960 (nomen nudum)
- Genera brought into synonymy
- Acrilla H. Adams, 1860: synonym of Amaea H. Adams & A. Adams, 1853
- Acutiscala de Boury, 1909 : synonym of Epitonium Röding, 1798
- Amiciscala Jousseaume 1912 : synonym of Epitonium Röding, 1798
- Asperiscala de Boury, 1909: synonym of Epitonium Röding, 1798
- Cinctiscala de Boury 1909 : synonym of Asperiscala de Boury, 1909
- Cirratiscala de Boury, 1909 : synonym of Epitonium Röding, 1798
- Clathroscala de Boury 1889 : synonym of Amaea H. Adams & A. Adams, 1853
- Clathrus Oken 1815 : synonym of Epitonium Röding, 1798
- Compressiscala Masahito (Prince) & Habe 1976 : synonym of Gregorioiscala Cossmann, 1912
- Dannevigena Iredale 1936 : synonym of Cirsotrema Mörch, 1852
- Foliaceiscala de Boury 1912 : synonym of Epitonium Röding, 1798
- Fragiliscala Azuma 1962 : synonym of Amaea H. Adams & A. Adams, 1853
- FragilopaliaAzuma 1972 : synonym of Amaea H. Adams & A. Adams, 1853
- Glabriscala de Boury 1909 : synonym of Epitonium Röding, 1798
- Lampropalia Kuroda & Ito, 1961 : synonym of Cylindriscala de Boury, 1909
- Mazescala Iredale 1936 : synonym of Epitonium Röding, 1798
- Nipponoscala Masahito (Prince) & Habe 1973 : synonym of Epitonium Röding, 1798
- Nodiscala de Boury 1889 : synonym of Opalia H. Adams & A. Adams, 1853
- Nystiella Clench & Turner, 1952 : synonym of Opaliopsis Thiele, 1928
- Sagamiscala Masahito, Kuroda & Habe, 1971 : synonym of Globiscala de Boury, 1909
- Scala Mörch, 1852 : synonym of Epitonium Röding, 1798
- Scalina Conrad, 1865 : synonym of Amaea H. Adams & A. Adams, 1853
- Spiniscala de Boury, 1909 : synonym of Epitonium Röding, 1798
- Turbiniscala de Boury 1909 : synonym of Epitonium Röding, 1798
- Viciniscala de Boury 1909 : synonym of Epitonium Röding, 1798
- Berry S. S. (1910). "(Review of) Report on a collection of shells from Peru, with a summary of littoral marine Mollusca of the Peruvian zoological province. By William Healey Dall: Proc. U. S. N. M. 37, pp. 147-294, Pls. 20-28, 1909". The Nautilus 23(10): 130-132.
- Art Weil (1999). "Conchologists of America List". University of Georgia. Retrieved 2009-03-23.
- Gofas, S. (2010). Epitoniidae. In: Bouchet, P.; Gofas, S.; Rosenberg, G. (2010) World Marine Mollusca database. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=132 on 24 April 2011
- J. Wyatt Durham (1937). "Gastropods of the family Epitoniidae from mesozoid and Cenozoic rocks of the West Coast of North America". Journal of Paleontology. 11 (6): 479–512. JSTOR 1298354.
- Collin, Rachel (2000). "Development and anatomy of Nitidiscala tincta (Carpenter, 1865) (Gastropoda: Epitoniidae)". The Veliger 43(4): 302-312.
- "Conchologists of America List". University of Georgia. 1999. Retrieved 2009-03-23.
- A. Weil, L. Brown and B. Neville, 1999, The Wentletrap Book: A Guide to the Recent Epitoniidae of the World, Mal de Mer Enterprises
- Neville, Bruce (1997). A Master Index to the Species Names in the Family Epitoniidae (PDF). Albuquerque, New Mexico: privately published. p. 59.
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