text large_stringlengths 148 17k | id large_stringlengths 47 47 | score float64 2.69 5.31 | tokens int64 36 7.79k | format large_stringclasses 13
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Environmental Issues: Water
All Documents in Water Tagged conservation and restoration
- Re-Envisioning the Chicago River
Adopting Comprehensive Regional Solutions to the Invasive Species Crisis
- In response to a public health emergency more than 100 years ago, engineers reversed the Chicago River and built the Chicag... | <urn:uuid:04154293-3767-45ae-a1a3-19149958d075> | 3.359375 | 593 | Content Listing | Science & Tech. | 22.452563 |
|REBOL 3 Docs||Guide||Concepts||Functions||Datatypes||Errors|
|TOC < Back Next >||Updated: 18-Feb-2009 Edit History|
As previously mentioned, blocks are not normally evaluated. A do function is required to force a block to be evaluated. There are times when you may need to conditionally evaluate a block. The following ... | <urn:uuid:bea7696b-bf1a-491a-a53c-fd443f448aaa> | 3.28125 | 1,289 | Documentation | Software Dev. | 65.420946 |
The turacos, also known as plantain eaters and go-away birds, make up the bird family Musophagidae (literally banana-eaters). In southern Africa both turacos and go-away birds are also commonly known as louries. Traditionally this group has been placed in the cuckoo order Cuculiformes, but Sibley-Ahlquist taxonomy rais... | <urn:uuid:dec41c90-a812-49e0-ae94-6248bb1cae87> | 3.453125 | 292 | Knowledge Article | Science & Tech. | 47.168022 |
Next time kids say they don’t like vegetables, try out an experiment that will bring out the fun side of our leafy friends. Mom and Kiddo of the blog What Did We Do All Day? shows us how to play with color in this demonstration that uses an acid, a base, and a vegetable. She suggests keeping some of the solution in the... | <urn:uuid:475dafb3-3e0e-4ae0-ab1d-b660d4fb18e8> | 3.21875 | 564 | Personal Blog | Science & Tech. | 69.737857 |
Remember the headline from a few days ago about the impending supernova from "nearby" recurring nova T Pyxidis? T Pyxidis is a star which goes boom every 20 years, but hasn't had an event since 1967. This week some astronomers suggested T Pyxidis is headed for supernova, one of the aftereffects of which would be the st... | <urn:uuid:335b5a41-3f40-468c-905f-753ef1ced79b> | 3.375 | 294 | Personal Blog | Science & Tech. | 55.035692 |
From Ed Yong:
All modern penguins wear a suit of black feathers, but prehistoric members of the group didn’t go for the dinner jacket look. A newly discovered penguin, known as Inkayacu, was dressed in grey and reddish-brown hues.
It is neither the oldest nor the largest penguin fossil, it doesn’t hail from a new part ... | <urn:uuid:4658e48b-2f34-438d-bf60-cb0313a38d47> | 3.203125 | 269 | Personal Blog | Science & Tech. | 43.783462 |
Rowe, J. E. and Kelly, M. and Hewitt, CN (1993) The occurrence of high indoor radon levels in carboniferous bedrock areas of NW England. Radiation Protection Dosimetry, 46 (3). pp. 201-205.Full text not available from this repository.
In NW England, certain types of bedrock of Carboniferous age have been found to have ... | <urn:uuid:8e863161-2620-40b2-a2f8-a88c7c05e11d> | 2.875 | 293 | Academic Writing | Science & Tech. | 39.292883 |
Using the VSEPR theory
one can easily determine
what is repeling
what in a molecule
, however, determining the shape
of the mole
cule can be annoying at time
In order to help out with this problem here is a list that will help you determine the shape of a simple molecule given the number of electron pairs:
(Seeing as A... | <urn:uuid:2811d171-a237-4680-8427-927bd72e520e> | 3.546875 | 715 | Tutorial | Science & Tech. | 57.290591 |
From Global Warming Art
This figure compares the global average surface temperature record, as compiled by Jones and Moberg (2003; data set TaveGL2v with 2005 updates), to the microwave sounder (MSU) satellite data of lower atmospheric temperatures determined by Christy et al. (UAH 2003; data set tltglhmam version 5.2 ... | <urn:uuid:7f7e7af3-5097-492b-9f0f-9ec4e687717f> | 3.296875 | 901 | Knowledge Article | Science & Tech. | 60.488932 |
Solve for real numbers x, y, and z
Graph the 3 equations with Graphing Calculator as 3D. The image shows three intersecting tubes with elliptical cross-sections. Click here to open a GCF file. (You must have Graphing Calculator 3.5 to open this file but the image could be graphed with other software.) Opening in GC 3.5... | <urn:uuid:8b986600-f3e9-4ed2-a4d0-eb10797d5157> | 3.28125 | 203 | Tutorial | Science & Tech. | 75.425 |
In that video, the speaker conceptualizes a clock that measures time by reflections of light. If we consider speed of light as reference to our time measurement, I guess it is natural to expect that our time measurements will be warped if we are traveling at speeds comparable to that of light.
I was wondering, what if ... | <urn:uuid:a5a683e3-ffee-4e10-a88c-6c3c170975e0> | 3.1875 | 205 | Q&A Forum | Science & Tech. | 56.37947 |
|S/2004 S 1|
|discovery by||Sébastien Charnoz|
|date of the discovery||2004|
|data of the orbit|
|course radius||194,000 km|
|scan time||1.0083 days|
|natural satellite||of the Saturn|
|mass||1,65×10 13 kg kg|
|of density||1.17 g/cm 3|
|gravitation at the surface||0,000 48 m/s 3|
|atmospheric pressure||0 kPa|
Table of ... | <urn:uuid:564f8307-9e48-420b-ab0f-cf3a7d9603bb> | 2.6875 | 619 | Knowledge Article | Science & Tech. | 53.571918 |
Ask a question about 'Beta Cephei variable'
Start a new discussion about 'Beta Cephei variable'
Answer questions from other users
Beta Cephei variables
are variable stars which exhibit variations in their brightness due to pulsations of the stars' surfaces. The point of maximum brightness roughly corresponds to the max... | <urn:uuid:f1ae5f8a-246f-4421-a6ae-181d8eb11f51> | 3.640625 | 533 | Q&A Forum | Science & Tech. | 54.359854 |
Science Fair Project Encyclopedia
Mercury programming language
Mercury is compiled rather than interpreted, as is traditional for logic languagues. It features a sophisticated, strict type and mode system. Its authors claim these features and logic programming's abstract nature speeds writing of reliable programs. Merc... | <urn:uuid:8b95ca34-78dc-4286-9be9-81af35ebfa5d> | 2.703125 | 241 | Knowledge Article | Software Dev. | 22.699148 |
Characteristics of Life
Characteristics of life include living things that are made of cells or cell products, use energy, respond to changes in the environment, maintain homeostasis and reproduce with similar offspring. These characteristics define whether something is living or not.
When people start studying what is... | <urn:uuid:5e03e228-9335-4f67-a651-ee3da9563ace> | 3.453125 | 729 | Knowledge Article | Science & Tech. | 54.358403 |
This isn’t actually about brain control. Not really, anyway. If I really knew anything about brain control, I’d be out taking over the world, not writing blog posts (and mark my words, I’d be making Jake Gyllenhaal my number one minion. Yum). It’s really about a technique called Transcranial Magnetic Stimulation, how a... | <urn:uuid:ca3b1c49-72bc-4e9e-9a65-eb4583e27f0b> | 2.75 | 1,647 | Personal Blog | Science & Tech. | 51.07732 |
Apache HTTP Server Version 2.0
This document covers stopping and restarting Apache on Unix-like systems. Windows NT, 2000 and XP users should see Running Apache as a Service and Windows 9x and ME users should see Running Apache as a Console Application for information on how to control Apache on those platforms.
In ord... | <urn:uuid:1c7310bb-4caf-4d6c-af66-6cd8672a16db> | 2.953125 | 1,400 | Documentation | Software Dev. | 51.786652 |
See more from this Session: Symposium--Changes In Soil Carbon Due to Climate and Human Activities
Wednesday, October 19, 2011: 8:05 AM
Henry Gonzalez Convention Center, Room 209, Concourse Level
Changes in soil organic carbon (SOC) stocks and its distribution in depth due to land use change have been reported worldwide... | <urn:uuid:b6486f0f-5dfd-4275-bd67-a4b8e53f9af2> | 2.765625 | 407 | Academic Writing | Science & Tech. | 50.863721 |
Flat-screen TV manufacturing emits chemical with warming effect (09.29.2008)
An unregulated chemical used to make flat-screen televisions and computers has 17,000 times the climate-warming effect of carbon dioxide, say UC Irvine Earth system scientists Michael Prather and Juno Hsu. Their assessment of nitrogen trifluor... | <urn:uuid:78abd39b-ac9e-4133-b9aa-a89fcd81bfad> | 3.3125 | 773 | Audio Transcript | Science & Tech. | 42.241567 |
Photo courtesy of Beyond The Rhetoroic by Michael Kwan and the movie Ice Age
Scientists have reported the discovery of a saber tooth squirrel. It seems squirrels have managed to survive a VERY long time. In the journal Nature, lead researcher Guillermo Rougier, a professor from the University of Louisville, reported th... | <urn:uuid:2de1bba4-eb96-4de5-bd23-48e4aa402a4b> | 3.3125 | 530 | Personal Blog | Science & Tech. | 46.089116 |
In general relativity Eddington–Finkelstein coordinates are named for Arthur Stanley Eddington and David Finkelstein, even though neither ever wrote down these coordinates or the metric in these coordinates. They seem to have been given this name by Misner, Thorne, and Wheeler in their book Gravitation. They are a pair... | <urn:uuid:60d8c57c-07e3-44f4-a951-59be79fb57b1> | 3.46875 | 1,280 | Knowledge Article | Science & Tech. | 38.63101 |
I recently came across an interesting programming challenge, which I can summarise here.
Develop a first-in/first-out (FIFO) queue in a programming language of your choice. The following constraints apply:
- You must use a linked-list, and can’t use arrays, hashes or other sophisticated enumerations;
- The queue must b... | <urn:uuid:8684f30e-184f-4cd3-89d3-66ecedd94409> | 2.84375 | 340 | Personal Blog | Software Dev. | 27.715248 |
Structures & Unions in C : - C Programming Tutorial
contains number of data types grouped together.
These data types may or may not be of same type.
We can pass structures as arguments to functions.
We can also make structure within a structure.
Use of Typedef in C language
C provides a facility called typedef for crea... | <urn:uuid:acac171a-e332-4933-9948-389f30f4dd47> | 3.359375 | 157 | Documentation | Software Dev. | 44.422876 |
OBJECTIVES: Develop and maintain a capability to provide aerial surveys of marine bird and mammal distribution and abundance for oil spill response and post-spill injury assessment.
TIME PERIOD: June 1994 through October 1998
STUDY AREA: Coastal and inland marine waters of California.
METHODOLOGY: ... Aerial surveys we... | <urn:uuid:b8de9cc8-515c-4676-8888-bdbb364da2f5> | 2.796875 | 616 | Academic Writing | Science & Tech. | 31.641814 |
4.3. Velocity versus Density
The peculiar velocity data is compared with the distribution of galaxies in redshift space to obtain . The comparison can be performed either at the density level (e.g., velocity-inferred mass density a la POTENT versus real-space density of galaxies as extracted from redshift surveys ), or... | <urn:uuid:68f378b7-17ee-4c30-8e08-862c1ef245a0> | 2.765625 | 380 | Academic Writing | Science & Tech. | 45.856381 |
That cloaking device we've been dreaming of appears to be one step closer to actual cloakdom, so start pondering the mischievous possibilities.
Scientists from Duke University have improved on their earlier efforts at producing an invisibility cloak, coming up with a new type of device they say is significantly more so... | <urn:uuid:077eda4a-703d-49a1-95cc-c6b4868a21a7> | 3 | 222 | Truncated | Science & Tech. | 35.413669 |
A podcast is a an audio file published on the web. The files are usually downloaded onto computers or portable listening devices such as iPods or other players.
Read more about podcasting from webcontent.gov
HOST: Welcome to Diving Deeper where we interview National Ocean Service scientists on the ocean topics and info... | <urn:uuid:f4cb11fb-9eb9-45e1-8918-2b4e9c470cdc> | 3.609375 | 3,142 | Audio Transcript | Science & Tech. | 47.844716 |
Sometimes it is possible to do volume and surface integrals as ordinary integrals without bothering with the general approach discussed in previous sections.
This happens when both your integrand and your region of integration have sufficient symmetry that you can do all but one of the integrals by inspection in the mu... | <urn:uuid:2548f6d3-9b83-42bb-92d0-d588b2a40954> | 3.390625 | 736 | Tutorial | Science & Tech. | 46.251956 |
I haven’t had a chance to read the original paper – I’m getting ready to head out of town and probably won’t get to it until next week, but I just got a press release from U Alaska Fairbanks about a recent paper in this month’s issue of Science that suggests that we’ve got bigger methane problems than we knew about.
Fr... | <urn:uuid:e3eb9ee7-4fc0-4450-9867-843355a7c276> | 2.9375 | 1,174 | Personal Blog | Science & Tech. | 35.737057 |
With high speed photography, I can use a high voltage spark to create a flash of only 1/1,000,000th of a second in duration. The problem is that there are not a lot of things that move this fast that such a flash is required to stop the motion. Bullets are such a subject requiring a very high speed flash system. Around... | <urn:uuid:a5b38e5e-1fdb-47fc-9604-6950d8ec95b7> | 3 | 388 | Personal Blog | Science & Tech. | 63.999634 |
COBOL (Common Business Oriented Language) was the first widely-used high-level programming language for business applications. Many payroll, accounting, and other business application programs written in COBOL over the past 35 years are still in use and it is possible that there are more existing lines of programming c... | <urn:uuid:b32b18a2-7a67-4246-8f7a-91c9512d8577> | 3.234375 | 241 | Knowledge Article | Software Dev. | 25.219535 |
Saturday 18 May
Yellow-throated apalis (Apalis flavigularis)
Yellow-throated apalis fact file
- Find out more
- Print factsheet
Yellow-throated apalis description
An endangered warbler, the yellow-throated apalis (Apalis flavigularis) is distinguished from other species of the Apalis genus by its vivid yellow colourati... | <urn:uuid:4ec6bed3-347d-432e-9a42-ae88abce5a10> | 4.03125 | 1,739 | Knowledge Article | Science & Tech. | 30.692111 |
The Research of Dr. Harold Zakon
ur lab studies a number of questions using weakly electric fish as our model organism. These fish live in murky waters and are nocturnally active. They generate weak electric fields around themselves from a specialized electric organ and sense these electric fields, with specialized sen... | <urn:uuid:ab9321e9-211c-4af5-94c5-4d94b128bbf5> | 3.3125 | 482 | Academic Writing | Science & Tech. | 26.186322 |
Most Popular Links
Lampyridae Level 1 Level 2
|Key Characters (adult)||
Fireflies, lightningbugs, glowworms. Adults soft-bodied, elongate; color generally black, with red markings on the pronotum; antennae with 8-13 (usually 11) segments, filiform, serrate or branched in some taxa; tarsi 5-segmented, next-to-last segme... | <urn:uuid:edc531cc-321b-4d98-bcae-8a86ab64f4e8> | 2.734375 | 181 | Knowledge Article | Science & Tech. | 20.876029 |
Good job bringing this to light. People won't realise how huge the problem is and municipalities are woefully ill equipped to...
Agreed; mining can never be sustainable, but then how do you get the metals to make all the things you need in the course of...
Very good piece.
Debris cover also affects glacial retreat rate... | <urn:uuid:fda6e82b-589e-405d-b518-3ba4766f0346> | 3.484375 | 727 | Comment Section | Science & Tech. | 32.497868 |
Daniele Bochicchio, Stefano Mostarda, and Marco De Sanctis are authors of ASP.NET 4.0 in Practice.
With so many multicore CPUs on the market, multithreading and parallel execution are becoming more popular topics among developers. Both multithreading and parallel execution aim at reducing computing time, providing bett... | <urn:uuid:2d979a1f-8cd1-4bc3-90d8-b2e799abea7b> | 3.359375 | 580 | Knowledge Article | Software Dev. | 38.26252 |
Contact: Bill Steigerwald
NASA/Goddard Space Flight Center
Caption: New research from NASA's Lunar Science Institute indicates that the solar wind may be charging certain regions at the lunar poles to hundreds of volts. In this short video Dr. Bill Farrell discusses this research and what it means for future exploratio... | <urn:uuid:907ebac3-8c73-422b-85ef-671d698b5c59> | 2.984375 | 100 | Truncated | Science & Tech. | 37.076 |
Using this graphic and referring to it is encouraged, and please use it in presentations, web pages, newspapers, blogs and reports.
For any form of publication, please include the link to this page and give the cartographer/designer credit (in this case UNEP/GRID-Arendal)
Houghton, J.T., et al. (editors). 2001. Climate... | <urn:uuid:8461a624-2738-4dd7-a5ac-cb4ba8b3bb21> | 3.375 | 471 | Knowledge Article | Science & Tech. | 37.267471 |
A Keymap lets an application bind key
strokes to actions.
In order to allow keymaps to be shared across multiple text components, they
can use actions that extend TextAction.
TextAction can determine which JTextComponent
most recently has or had focus and therefore is the subject of
the action (In the case that the Act... | <urn:uuid:9301fa2e-7c6c-467d-9841-2a5321aa0bcd> | 3.46875 | 674 | Documentation | Software Dev. | 31.886485 |
In this chapter we discuss how to program a leveleditor that can used in any arraybased game. An arraybased game might be a Breakout clon, Boulderdash, PacMan or a Nibbles clone like our game Snakin, where we used this leveleditor too. Before you start reading this article you should know something about arrays in Java... | <urn:uuid:c8892482-82e8-4122-81ef-f6b750257162> | 2.984375 | 1,879 | Tutorial | Software Dev. | 51.115872 |
The great 1997 El Niño snuck up on us. Once here, it seemed to spawn an
entire industry last year, the business of El Niño forecasting. We kept
track of some of the major predictions, matched them up with what actually
happened, and tabbed the results to get a sense of just how good the
forecasters have gotten.
Date of... | <urn:uuid:cd411ddb-4118-4347-bec7-f95cbee587e5> | 3.109375 | 1,077 | Structured Data | Science & Tech. | 37.650766 |
Black Hole Computers; Reality-Bending Black Holes; Special Editions; by Seth Lloyd and Y. Jack Ng; 10 Page(s)
What is the difference between a computer and a black hole? This question sounds like the start of a Microsoft joke, but it is one of the most profound problems in physics today. Most people think of computers ... | <urn:uuid:48d9203f-33a9-4f70-9104-2133ea032a6e> | 3.453125 | 349 | Truncated | Science & Tech. | 40.678824 |
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2001 August 16
Explanation: Its core hidden from optical view by a thick lane of dust, the giant elliptical galaxy Centaurus A was among the first o... | <urn:uuid:3071b08c-027c-48b9-8e40-520fea9c48c2> | 3.765625 | 323 | Knowledge Article | Science & Tech. | 47.113533 |
Overview of molluscs - Phylum Mollusca
Snails, slugs, clams, mussels, squids and octopuses are all very different-looking animals. However, they are all molluscs.
Molluscs live almost everywhere - on the rocky shore, in freshwater habitats and in your garden.
Generally molluscs have:
- an unsegmented, soft body
- a mus... | <urn:uuid:56bbcaa1-30f9-449a-bf6c-522ada1a6d16> | 3.65625 | 324 | Knowledge Article | Science & Tech. | 38.062 |
Skip to Main Content
Your organization might have access to this article on the publisher's site. To check, click on this link:http://dx.doi.org/+10.1063/1.1146959
A new balloon‐borne instrument designed by the author detects x rays produced in thunderstorms. The instrument uses a sodium iodide (NaI) scintillation dete... | <urn:uuid:d8a0e4d6-aceb-4b94-aaf6-1d3279ebbcf6> | 3.5625 | 186 | Truncated | Science & Tech. | 63.715696 |
|Table 1: Global Warming Potentials for Common Greenhouse Gases |
In 1978, the United States federal government banned the use of Chlorofluorocarbons (CFCs) in aerosol cans. The cited reasons had to do with the extremely detrimental effect that the emissions of these gases had on the depletion of ozone in the atmospher... | <urn:uuid:d9777ddc-04d3-4715-8347-016d3e068df2> | 3.828125 | 1,319 | Academic Writing | Science & Tech. | 34.526103 |
A Search for Transiting Exoplanets
Over 270 planets are now known to be orbiting stars other than the Sun. Most of these planets were detected using the radial velocity method, which involves measuring (using spectroscopy) the "wobble" of the star due to the planet's gravitational pull. An alternative used by an increa... | <urn:uuid:22414ae5-c646-4112-97a5-14db2d844e1f> | 3.5 | 907 | Academic Writing | Science & Tech. | 35.695757 |
There are many ways to execute external commands from Perl. The most commons are:
- system function
- exec function
- backticks (``) operator
- open function
All of these methods have different behaviour, so you should choose which one to use depending of your particular need. In brief, these are the recommendations:
|... | <urn:uuid:c2a98029-146f-4903-a0fa-fafd0fbdc8e6> | 3.359375 | 849 | Tutorial | Software Dev. | 54.800714 |
Techniques and Methods 6-A35
The computer program PHAST (PHREEQC And HST3D) simulates multicomponent, reactive solute transport in three-dimensional saturated groundwater flow systems. PHAST is a versatile groundwater flow and solute-transport simulator with capabilities to model a wide range of equilibrium and kinetic... | <urn:uuid:a4be439a-d1b2-4088-b752-83ba388b0778> | 2.734375 | 820 | Documentation | Science & Tech. | 30.998977 |
I hope I am not bothering you in any way, but there is a question that has been bothering me for awhile now. I have asked my teacher but he does not know the answer. I have been researching it online and in some text books for about a month now and have come up with nothing. I do not want this to seem like my math teac... | <urn:uuid:50fa0361-d88b-4e73-a18b-6c8623d199c7> | 3.265625 | 1,098 | Q&A Forum | Science & Tech. | 66.73121 |
A fullerene is any molecule composed entirely of carbon, in the form of a hollow sphere, ellipsoid, or tube. Spherical fullerenes are also called buckyballs, and they resemble the balls used in association football. Cylindrical ones are called carbon nanotubes or buckytubes. They are usually made in the form of a hollo... | <urn:uuid:e785c310-d9b4-4ea9-9765-cd71e7c8886a> | 3.53125 | 131 | Knowledge Article | Science & Tech. | 24.476391 |
In the animal kingdom, slugs and snails belong in the phylum Mollusca, a word meaning 'soft animal'.
The number of different species of mollusc varies, according to the source, but is estimated to vary between 30.000 and 120.000 living species. Members of the group are found in nearly all available biotopes on earth.
T... | <urn:uuid:140ea6f7-e672-485b-ade7-770c9358fd7c> | 3.421875 | 202 | Knowledge Article | Science & Tech. | 54.170797 |
How to Watch
This is the most important question after ‘when is it happening?’. Looking directly at the Sun is sheer stupidity, so you’ll need some equipment.
The cheapest and least effort-requiring alternative
Solar goggles will be sold in your neighbouring areas somewhere. Get them. Make sure that these are proper by... | <urn:uuid:b8855123-477c-48a3-bf6b-a8065c1e9fc4> | 3.15625 | 1,220 | Tutorial | Science & Tech. | 67.343861 |
Science Fair Project Encyclopedia
Kuiper Airborne Observatory
The Gerard P. Kuiper Airborne Observatory (KAO) was a national facility operated by NASA to support research in infrared astronomy. The observation platform was a highly modified C-141A jet transport aircraft with a range of 6000 nautical miles, capable of c... | <urn:uuid:41831ffe-6449-4f82-969e-9acf14b44306> | 3.84375 | 356 | Knowledge Article | Science & Tech. | 34.918239 |
Simply begin typing or use the editing tools above to add to this article.
Once you are finished and click submit, your modifications will be sent to our editors for review.
...auratus) of eastern North America, which has more than 100 local names. This golden-winged form, which measures about 33 cm (13 inches) in leng... | <urn:uuid:f29a504e-90aa-4807-af7a-44a7a886fab3> | 3.265625 | 156 | Knowledge Article | Science & Tech. | 61.724394 |
Team Number: 068
School Name: Shiprock High School
Area of Science: Environmental Science
Project Title: Water Pollution
Our definition of water pollution is the contamination or pollution of the water caused by human activities, either intentionally or accidentally. An example of the intentional pollution of water is ... | <urn:uuid:e9b9f534-8a91-4c5a-b6d1-19ce513632ff> | 3.359375 | 169 | Academic Writing | Science & Tech. | 31.461847 |
Wind can be used to do work. The kinetic energy of the wind can be changed into other forms of energy, either mechanical energy or electrical energy.
When a boat lifts a sail, it is using wind energy to push it through the water. This is one form of work.
Farmers have been using wind energy for many years to pump water... | <urn:uuid:e5998359-1f65-4a7f-baa6-3641e355ed88> | 3.1875 | 713 | Knowledge Article | Science & Tech. | 59.961642 |
Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ -¹ ² ³ °
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That is always a danger and some of that will definitely happen. Everyone has slowed down with mental calculation.
I am still learning though. F... | <urn:uuid:91ced5cc-5111-4759-ade4-387f9921f6c8> | 2.96875 | 676 | Comment Section | Science & Tech. | 71.167528 |
GLACIOLOGISTS are in dispute over how a highly contentious claim about the speed at which glaciers are melting came to be included in the latest report of the Intergovernmental Panel on Climate Change.
A decade ago, New Scientist reported (5 June 1999, p 18) a comment by the leading Indian glaciologist Syed Hasnain, wh... | <urn:uuid:7db5161c-8988-40cf-b98a-e45bc3279d6f> | 2.921875 | 219 | Truncated | Science & Tech. | 47.971184 |
We're thinking about probability more often than we might realise. Even weather...
We're thinking about probability more often than we might realise. Even weather forecasts are, at heart, 'chances are' reports
- Duration: 10 mins
- Published on: Wednesday 5th January 2005
- Introductory Level
- Posted under: Statistics... | <urn:uuid:905db292-e71b-4785-b5ce-6dba1a7961ae> | 3.40625 | 1,467 | Knowledge Article | Science & Tech. | 53.682524 |
At the 2010 Olympic Winter Games in Vancouver, 20 lasers were used in a
nightly light show in which people from around the world controlled the beams
through public Internet access.
mirror—which was made of
aluminized Mylar and spanned
90 feet across. In the main hall,
visitors could see their reflections hanging upsid... | <urn:uuid:0ae98c4e-6ec1-4e32-b2f7-32a11e631a02> | 3.140625 | 1,000 | Nonfiction Writing | Science & Tech. | 44.638474 |
Keplerian orbital elements
Filed under explaining science
In this diagram, an orbital plane (yellow) intersects a reference plane (gray). For objects in solar orbit, the reference plane is usually the plane of the ecliptic. The intersection is called the line of nodes, as it connects the center of mass with the ascendi... | <urn:uuid:6858f45b-22ea-4f4a-961c-6f52e5e96024> | 3.84375 | 145 | Knowledge Article | Science & Tech. | 31.08875 |
A robotic sensor that won an R&D 100 Award in 2009 has been put to use by Woods Hole Oceanographic Institution (WHOI) in Gulf of Maine coastal waters to monitor the way red tides behave. These harmful algal blooms, which generate a potentially fatal toxin, can be a challenge to track or predict. The Environmental Sampl... | <urn:uuid:4d90564d-a2b9-4d25-a351-fec331e3f09e> | 3.078125 | 1,864 | Content Listing | Science & Tech. | 22.756667 |
Here is a listing of the most
commonly used terms and definitions associated with Weather.
Absolute humidity: The mass of water vapor in a given volume of air( i.e., density of water vapor in a given parcel, usually expressed in grams per cubic meter
Actual vapor pressure: The partial pressure exerted by the water vapo... | <urn:uuid:88ae5dd6-6198-4f7d-b393-4fb0cfa21388> | 4.03125 | 636 | Structured Data | Science & Tech. | 36.427746 |
NOTE: Click on the image to view it at its highest resolution.
This is an image obtained with the 0.91-meter Spacewatch Telescope of the University of Arizona Observatories on Kitt Peak in Arizona by Jim Scotti, on 1993 March 30 at a mid-time of 07:26:13 UT. The total integration time was 440 seconds. North is to the r... | <urn:uuid:fc49f1f0-cbdd-458b-80f7-2e1e1b5dd23b> | 3.203125 | 290 | Knowledge Article | Science & Tech. | 66.748854 |
The bryophyte groups – Which bryophyte is it? - Leaves
Racomitrium pruinosum is a widespread moss in the southern hemisphere. It is fairly robust and can form extensive carpets on exposed rocks or soil, especially in mountainous areas. It is pale in colour and quite hoary when dry. The photos below show, on the left, p... | <urn:uuid:72fcafbc-dee8-4e52-a588-28ec504126f5> | 3.109375 | 361 | Knowledge Article | Science & Tech. | 56.213044 |
Dramatic change in the chemistry of the atmosphere has
occurred over the last century due to human activity.
1. From the GISP2 ice core it was determined that levels of sulfate and nitrate (the primary components of acid rain) in the North Atlantic and much of the Northern Hemisphere have greatly exceeded their natural... | <urn:uuid:730c1409-84e8-459d-92e2-225fc5bf56d4> | 3.59375 | 1,018 | Academic Writing | Science & Tech. | 61.270029 |
A Brief History of Antarctic Drilling
Russian scientists have just reported that they have successfully drilled into Lake Vostok, a vast, tepid body of water that rests under kilometers of ice beneath Antarctica’s glacial surface. Most news reports make mention of the long-duration drilling effort that it took to make ... | <urn:uuid:e63e959b-6833-4abf-861b-f0974783bfcd> | 3.40625 | 689 | Personal Blog | Science & Tech. | 38.165664 |
Grab your warm jackets and binoculars and help dedicated volunteers record a snapshot of winter bird distribution in North America.
The first survey, conducted on Christmas Day in 1900, was organized by Frank Chapman of the fledgling Audubon Society. Audubon chapters across the continent have continued this tradition y... | <urn:uuid:3ff11386-354b-4beb-b89b-7d60c89786ca> | 3.765625 | 139 | Knowledge Article | Science & Tech. | 34.365181 |
According to astronomers studying background radiation data gathered by the Planck Space probe, the universe is 80-million years older than previously thought. So now when somebody asks you how old the universe is, you can confidently tell them, "80-million years older than previously thought" because you never knew th... | <urn:uuid:722fc390-09f2-4d79-b838-a578351e5911> | 2.796875 | 363 | Personal Blog | Science & Tech. | 56.289349 |
See also the
Dr. Math FAQ:
Browse High School Logic
Stars indicate particularly interesting answers or
good places to begin browsing.
Selected answers to common questions:
- Logic and Conditional Sentences [10/04/2005]
I am having a hard time understanding why two false statements in a
conditional sentence makes it tru... | <urn:uuid:85d5e82c-26e3-4820-a028-031768c8657f> | 3.421875 | 1,706 | Q&A Forum | Science & Tech. | 66.603339 |
Via Via Meadia comes this news:
The Economist also brings us big news on the “settled science” of climate change. A new study has found soot to be twice as bad for climate as was previously thought, making it the second most damaging greenhouse agent after CO2. This is actually good news for two reasons.
First, soot is... | <urn:uuid:a63565b5-7b70-447a-b64b-8a4249ed3cc5> | 2.875 | 169 | Personal Blog | Science & Tech. | 50.892743 |
For those who were disenchanted with the results of the most recent United Nations Conference on Climate Change, a recent development gives at least one reason to be optimistic. The formation of the Climate and Clean Air Coalition to Reduce Short-Lived Climate Pollutants was announced on Thursday, February 16th by Unit... | <urn:uuid:9d228362-5460-4a57-b5ba-24e3d711d93e> | 3.671875 | 537 | Personal Blog | Science & Tech. | 20.986609 |
If one looks at planetary systems from the “modern” point of view provided by the HARPS survey and the results from Kepler’s recent data release, our own solar system looks pretty strange. In the Sun’s case, the frequently planetiferous orbital zones inside of P=50 days are completely, mysteriously barren. The orbital ... | <urn:uuid:f5c2b744-8d0b-46f6-b322-0c09526117ba> | 2.984375 | 671 | Personal Blog | Science & Tech. | 57.635514 |
Connecting the tropical Pacific with Indian Ocean through South China Sea
Article first published online: 21 DEC 2005
Copyright 2005 by the American Geophysical Union.
Geophysical Research Letters
Volume 32, Issue 24, December 2005
How to Cite
2005), Connecting the tropical Pacific with Indian Ocean through South China... | <urn:uuid:36abfb9c-fd38-4e54-8be5-cca5be8705d3> | 2.796875 | 264 | Academic Writing | Science & Tech. | 44.967619 |
| The Italian experimenter, Carlo Matteucci
(1811-1868), in experiments in the mid-eighteen forties, showed that the
effect worked over larger distances without the presence of iron. He devised
a pair of identical flat coils, with wire wound in a spiral pattern on
the surface of glass disks about 30 cm in diameter. A L... | <urn:uuid:f7f015e2-ff3d-4d1d-883d-5b87bd72f6c3> | 3.828125 | 190 | Knowledge Article | Science & Tech. | 41.909269 |
I am a physics novice.
Google tells me that electron microscopes work much like their optical counterparts -- but the analogy falls apart for me when I think about what I'm "viewing." Obviously, you can see light through the lenses, but what is the "image" analog for electron microscopes?
Is it at-all like spraying an ... | <urn:uuid:4e9e32fd-8f58-4f91-a06c-26c66a5a63ff> | 2.6875 | 188 | Q&A Forum | Science & Tech. | 54.53432 |
robo-animals, animal robots, and crittercams lie insects electronically modified to suit our purposes:
Mosquitoes (1st image)
In June, Network World ran an article about the development, over the last several years, of micro air vehicles (MAVs) - insect-sized devices disguised as dragonflies or mosquitoes and operated ... | <urn:uuid:f8038298-f9d7-4ece-84dd-8413c1af2f34> | 2.9375 | 481 | Personal Blog | Science & Tech. | 24.312164 |
Difference between Atomic Bomb and Hydrogen Bomb
For most people, the atomic bomb and the hydrogen bomb are pretty much the same thing with the only difference being their relative strengths. While this is partly true–with the hydrogen bomb being considerably more powerful–both types of bombs actually have a number of ... | <urn:uuid:e556c48e-c270-4b03-bcea-9609b0d490f0> | 3.5625 | 547 | Knowledge Article | Science & Tech. | 34.310923 |
Hybrid, a plant or animal whose parents belong to two different breeds, varieties, or species. In some cases the parents may even belong to different genera (groups of related species). Plant hybrids are constantly being produced in nature. Hybrids are also produced experimentally in the interests of scientific researc... | <urn:uuid:73389194-0294-486b-b927-2afee8d52005> | 3.640625 | 235 | Knowledge Article | Science & Tech. | 37.571444 |
techfun89 writes "Mars has returned to our evening skies as it does every two years. This time it is getting even more attention and buzz than it normally would. Amateur astronomer Wayne Jaeschke of West Chester Pennsylvania noticed an unusual protrusion in the planet's southern hemisphere, preceding the sunrise termin... | <urn:uuid:aba800b3-5045-4d96-9b25-04752e2d3a3b> | 2.953125 | 174 | Comment Section | Science & Tech. | 36.57777 |
David Charbonneau Harvard - Smithsonian Center for Astrophysics
"The Era of Comparative Exoplanetology"
When extrasolar planets are observed to transit their parent stars, we are granted
unprecedented access to their physical properties. It is only for these systems that we
are permitted direct estimates of the planeta... | <urn:uuid:beb51e01-974d-4920-8f80-b2a3f38e6d08> | 3.15625 | 3,661 | Content Listing | Science & Tech. | 29.957023 |
Authors: J. Bar-Sagi
The electromagnetic wave quantum-energy depends only on its frequency, not on the emitting system's radiation power. The proportionality constant between the frequency and the quantumenergy of the electromagnetic wave, the Planck's constant is in the essence of quantum mechanics. This constant is k... | <urn:uuid:df74f31d-9cfe-4de2-b6bb-5863250d8742> | 3.03125 | 314 | Truncated | Science & Tech. | 34.98969 |
What's that black dot moving across the Sun?
Possibly the clearest view of
in front of the Sun last week was from Earth orbit.
The Solar Dynamics Observatory obtained an uninterrupted vista
recording it not only in optical light but also in bands of
Pictured above is a composite movie of the crossing set to music.
Alth... | <urn:uuid:1783da5a-1cee-44d5-bae3-0dbd22d257be> | 2.765625 | 135 | Content Listing | Science & Tech. | 27.290585 |
Forcefield technology is one of the most massively useful technological advances ever made. Initially prophesied by science fiction in the early 20th century, this is one of those technologies which has developed along almost lines almost identical to those forecast by those early "imagineers". The first forcefield tec... | <urn:uuid:0940752e-3713-4061-b855-280cf60959f8> | 3.3125 | 1,740 | Knowledge Article | Science & Tech. | 29.774705 |
- Making A* on a GPU is silly : it needs random access on memory, slow with GPU.
- A* it's for finding path...
- Algorithm to find path a 'matrix' way ? Perhaps this
1) Build a matrix A, where A(i,j) = 0 if we can reach node(j) from node(i) in one step
2) For the matrix multiplications, replace + by max, and * by +
3) ... | <urn:uuid:f71f1c50-3dd1-4fe9-9285-86e44ce2570f> | 3.453125 | 370 | Comment Section | Software Dev. | 76.395831 |
Trajectory is the path a moving object follows through space. In physics class we'd create our own trajectory tests using a massive homemade sling shot – consisting of a bicycle helmet, stretchy surgical tubing and football field uprights. With a little bit of man power and your obligatory water balloon we'd fire our "... | <urn:uuid:c1810d7f-c810-410a-8183-964b79e6e4e2> | 3.375 | 198 | Personal Blog | Science & Tech. | 48.868432 |
Liquids Conducting Current
Name: Nathan U.
I am reviewing some materials for the electricity unit in
my physics classes. I have come across similar passages in different
texts as follows:
"A conductor in both the solid state and liquid state can carry a current
to complete an electrical circuit. However, a solid conduc... | <urn:uuid:2b1c5f22-6f74-4b86-817a-e88b2981061e> | 3.5625 | 884 | Q&A Forum | Science & Tech. | 28.812981 |
Skip Maine state header navigation
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Home > Explore! > Ground Water and Wells > Water Resources > Figure 2
Figure 2. Distribution of mapped sand and gravel aquifers in Maine, shown in green. Northwestern Maine is currently unmapped for sand and gravel aquifers but undoubtedly has some.
Last updated on... | <urn:uuid:75d9397c-2561-4f3f-a60a-f85e839bb274> | 2.90625 | 71 | Knowledge Article | Science & Tech. | 40.709231 |
The application development is not an easy task but yet designing is essential for this application. As it name suggests a user interface is something that users face every time they use your program. That is why it is necessary to create applications that meet the user's requirements on how the user interface should l... | <urn:uuid:ab6885e4-54b7-41ff-a060-7fdcccf5672f> | 3.0625 | 527 | Tutorial | Software Dev. | 29.867092 |
by TIM VASQUEZ / www.weathergraphics.com
This article is a courtesy copy placed on the author's website for educational purposes as permitted by written agreement with Taylor & Francis. It may not be distributed or reproduced without express written permission of Taylor & Francis. More recent installments of this artic... | <urn:uuid:fab68b56-32bf-4f00-a7e4-b6965b3372ee> | 4.125 | 958 | Knowledge Article | Science & Tech. | 56.828381 |
According to quantum mechanics, electrons bound to atoms occur in specific electronic configurations. The highest energy configuration (or energy band) that is normally occupied by electrons for a given material is known as the valence band, and the degree to which it is filled largely determines the material's electri... | <urn:uuid:874d024c-39ab-462b-896a-7ded94ac02f9> | 4 | 754 | Knowledge Article | Science & Tech. | 27.704634 |
Time Dilation and Quasars
In May of 2001 Hawkins published a paper called “Time Dilation and Quasar Variability”. Part of the Abstract reads as follows.
“We find that the timescale of quasar variation does not increase with redshift as required by time dilation. Possible explanations of this result all conflict with wi... | <urn:uuid:1eefb1e0-b25f-4139-b48d-2eb2dfc666a5> | 2.75 | 1,937 | Comment Section | Science & Tech. | 49.426213 |
Roots of the Derivatives of a Certain Real Polynomial in the Complex Plane
With and real, is a real polynomial with three roots: and . This Demonstration shows the roots of , , …, . Each of these derivatives has at most two nonreal roots (depending on the value of the real root ). As varies over the reals, these nonrea... | <urn:uuid:de05bb70-8418-49b7-bc63-8350c6300bb5> | 3.109375 | 262 | Academic Writing | Science & Tech. | 44.04491 |
In What is cloning? we learned what it means to clone an individual organism. Given its high profile in the popular media, the topic of cloning brings up some common, and often confusing, misconceptions.
Misconception #1: Instant Clones!
Let's say you really wanted a clone to do your homework. After reviewing What is C... | <urn:uuid:0b6bc1e9-72af-441f-8e37-2240aee77e54> | 3.1875 | 1,004 | Knowledge Article | Science & Tech. | 49.879771 |
In the limit of clean surfaces, friction has its origins in the microscopic, chemical interactions at the interface between the two objects in question. One of the more amazing (to me, anyway) consequences of this is the extremely important role played by commensurability between the surfaces. Let me explain with an ex... | <urn:uuid:b8c37183-eef9-41bb-a5a2-dc340dcd43f7> | 2.703125 | 332 | Personal Blog | Science & Tech. | 37.477448 |
Name: Mike T.
How do emitted photons instantaneously travel at
the speed of light since they were not accelerated? At one instant
there is no photon, and at the next instant, it miraculously is already
travelling at the speed of light.
Hi, Mike !!
A photon - as you know - is an electromagnetic (EM) wave .
Its energy is... | <urn:uuid:65375af2-ba61-4675-a330-c639bdfd4fc5> | 3.46875 | 713 | Q&A Forum | Science & Tech. | 58.744633 |
ASTR 160 - Lecture 3 - Our Solar System and the Pluto Problem
Lecture 3 - Our Solar System and the Pluto Problem
Class begins with a review of the first problem set. Newton's Third Law is applied in explaining how exoplanets are found. An overview of the Solar System is given; each planet is presented individually and ... | <urn:uuid:a17255e3-5e6d-4155-a3d7-dbc2ccc15735> | 3.359375 | 148 | Content Listing | Science & Tech. | 39.542822 |
Ever since the wheel was invented more than 5,000 years ago, people have been inventing new ways to travel faster from one point to another. The chariot, bicycle, automobile, airplane and rocket have all been invented to decrease the amount of time we spend getting to our desired destinations. Yet each of these forms o... | <urn:uuid:4f9522ea-7945-4f09-96f0-9327860a8edc> | 3.484375 | 448 | Knowledge Article | Science & Tech. | 29.154977 |
Coalescence with purifying selectionHow positive selection affects genealogies is demonstrated by the script genealogies_with_selection.py and discussed on page Genealogies 1. Here, we extend this discussion to purifying selection. Instead of an infinite sites model, we now use a finite sites model. Recurrent mutations... | <urn:uuid:6df63f5b-d468-4119-9549-56688cd700b5> | 2.703125 | 354 | Documentation | Science & Tech. | 25.81004 |