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has to invest, government’s biggest involvement with marriage today is the administration of breakups and the management of the carnage that often comes with them. Administratively, things were much easier |
for Ananiah and Tamut, which makes it impossible to replicate the arrangements of their day. But their preserved family records challenge us to think about whether we’ve really figured out |
Whenever citing a reference in the text source, it is made with its author’s surname and the year of publication is to be inserted in the text. Choose from the listed below to see examples: • Citing the author in the • Using direct quotes • Citing works by more |
than • Citing works by three or more authors • Citing a chapter of section • Citing an organization • Citing works by the same author written in the same year • Citing secondary sources Citing the Author in the Text Dogs were the first animals to be domesticated (Sheldrake, |
1999). If the author’s name occurs naturally in the sentence the year is given in brackets. Sheldrake (1999) asserted that dogs were the first animals to be domesticated. Using Direct Quotes If you quote directly from a source, you must insert the author’s name, date of publication and the page |
number of the quotation. The domestication of dogs, long predated the domestication of other animals (Sheldrake, 1999). Citing works by more than one Author If your source has two authors, you should include both names in the text. Anderson and Poole (1998) note that a “narrow line often separates plagiarism |
States, revenue from computer games now exceeds that of movies (Kline et al., 2003). Citing Chapter or Section When referring to a chapter or section which is part of a larger work, you should cite the author of the chapter not the editor of the whole work. The sea level |
has risen by approximately 10cm in the last 100 years (Mason, Citing an Organization If an organization or company (e.g., Department of Health, Arcadia Group Limited) is named as the author of a work rather than a person, you should cite their names. Make sure that you use the same |
version of the organizations name in both the Text and List of references (e.g., always use ‘Department of Health’, don’t abbreviate to ‘DoH’). Spain became a member of the United Nations in 1955 (United Nations, 2000). Citing Secondary Sources When citing secondary sources (i.e., an author refers to a work |
which you have not read) cite the secondary source, but include the name of the author and date of publication of the original source in the text. Only the secondary source should be listed in your List of references. You should only cite secondary sources if you are unable to |
Introduction to How Colorblindness Works Roses are red, violets are blue -- well, bluish. The sky is blue, too. Grass is green. These are things that most of us know for a fact and don't question. But what if you were colorblind? What would you see? Is life one long black-and-white movie? In "The Wizard of Oz," Dorothy... |
Kansas farmhouse and into the color-saturated Land of Oz. She moves from a humdrum existence of chores and troubles to an intense fantasyland peopled with curious creatures, trading in a clapboard house for yellow brick roads, red ruby slippers and a brilliant green city of emeralds. What would her transformation have ... |
We associate color with beauty, like in a gorgeous sunset. Some colors have meaning in and of themselves -- purple is for royals, red signifies passion. Colors seep into our expressions -- If we're depressed, we say we're feeling blue. We're also "green with envy," we "see red" and we might go "white with fear." Colors... |
green means go. Certain colors are said to help you sleep, while others make you hungry. And never underestimate the effect of a bright red dress. Color is important. In this article, we're going to learn what the world looks like for someone who's colorblind. |
You have to break a few (hundred) eggs to make a good crystal Space Science News home You have to break a few (hundred) eggs to make a good crystal |
Bell curve shape to crystal quality may point to best candidates for flight Sept. 20, 1999: Did you ever ask the teacher to grade a tough test "on the curve"? |
What you were asking was that the grades be adjusted so that a "C" fell under the part of the curve where most of your classmates had scored. A few |
were to the left and got a D or F; and few were to the right and got a B or an A. Right: To the crystallographer, this may not |
be a diamond but it's just as priceless. A lysozyme crystal grown in orbit looks great under a microscope, but the real test is X-ray crystallography. The colors are caused |
by polarizing filters. Links to 549x379-pixel, 69KB JPG. Credit: NASA/Marshall. That's basically how the bell curve works. In nature, objects and events quite often can be grouped along a bell |
curve. In a population of adult animals, most will be around the same size. A few will be larger and a few will be smaller. "If you talk to statisticians," |
noted Dr. Russell Judge of the University of Alabama in Huntsville, "variations within populations in nature can be described in terms of distributions." December 3: Mars Polar Lander nears touchdown |
December 2: What next, Leonids? November 30: Polar Lander Mission Overview November 30: Learning how to make a clean sweep in space The question now is whether scientists can use |
the microgravity of space to shift the curve to the right to grow the large, nearly perfect crystals they need for molecular lock-picking, the first step in designing drugs that |
can treat a broad range of diseases and disorders. "We want to determine how the growth of crystals effect their quality," Judge said in May when NASA selected his investigation |
for development, "and then take that into space to see how microgravity is enhancing the growth characteristics that lead to good crystals. From this we want to develop techniques, so |
that by observing crystal growth on the ground, we can predict which proteins are likely to benefit the most from microgravity crystallization." Sign up for our EXPRESS SCIENCE NEWS delivery |
These functions are a result not just of a chemical formula, but of structure which can be quite large (on the atomic scale) and fragile. If the shape isn't right, |
the protein cannot match up with other proteins or chemicals to do its job, just as the wrong key won't unlock a door. Sickle cell anemia, for example, results from |
structural differences in the hemoglobin that carries oxygen in red blood cells. Designing new treatments means designing altered proteins or other chemicals that act as a skeleton key or as |
a sophisticated lock pick. Proteins can form crystals, generated by rows and columns of molecules that form up like soldiers on a parade ground. Shining X-rays through a crystal will |
produce a pattern of dots that can be decoded to reveal the arrangement of the atoms in the molecules making up the crystal. Like the troops in formation, uniformity and |
order are everything in X-ray crystallography. X-rays have much sorter wavelengths than visible light, so the best looking crystals under the microscope won't necessarily pass muster under X-rays. Left: Judge |
(left) and Dr. Edward Snell, a National Research Council fellow working at NASA/Marshall, inspect the sample holder in the X-ray crystallography unit. Links to 600x616-pixel, 188KB JPG, or click here |
for a 1207x1240-pixel, 543KB JPG. Credit: NASA/Marshall. This has become an invaluable tool for understanding the structure and the function of dozens of proteins. But many proteins remain shrouded in |
mystery because on Earth crystal imperfections are introduced by fluid flows and the settling of the crystals to the bottom of the container. This leaves internal defects that distort or |
blur the view of the structure. "In order to have crystals to use for X-ray diffraction studies," Judge said, "you need them to be fairly large and well ordered." Scientists |
also need lots of crystals since exposure to air, the process of X-raying them, and other factors destroy the crystals. Getting just one perfect specimen isn't enough. Dozens may be |
needed, and the quality might not be known until well into the analysis. Research has Heavy Implications. July 1998. Crystal-clear view of insulin should lead to improved therapies for diabetics |
Growing protein crystals in the microgravity of space has yielded striking results, such as determining to a fine resolution how certain molecules of insulin join so scientists can improve injectable |
insulin needed by diabetics. There have also been disappointments when crystals in other experiments did not grow as expected. Since the 1970s, scientists have used a variety of approaches in |
trying to determine what leads to the growth of a large, perfect crystal. Judge tried a different approach that built on results noted by researchers dating as far back as |
1946. He and his team looked at the effects of concentration, temperature, and pH (acid vs. base) on the growth of lysozyme, a common protein in chicken egg white. Lysozyme's |
structure is well known and it has become a standard in many crystallization studies on Earth and in space. Although lysozyme has an atomic mass of 14,300 Daltons - almost |
92 times that of the ordinary sugar that many of us crystallized in elementary school science - it's a relative lightweight in the protein world. To exclude impurities often found |
in commercial lysozyme preparations, Judge and his team purified lysozyme extracted from eggs obtained from a local egg farm. While one experiment run required only five dozen eggs, the full |
series of experiment consumed about 200 eggs. Judge and his team grew the crystals in trays with small plastic wells filled with solutions containing a trace of salt to help |
stimulate crystal growth. Temperatures ranged from 4 to 18 deg C (39-64 deg F) and pH from 4.0 to 5.2 (slightly acidic; pure water theoretically has a pH of 7). |
Judge also varied the driving force behind the crystal growth process, called supersaturation, by varying the initial concentration of protein. Protein concentration must be set above a critical limit, the |
solubility, in order to form crystals (below this concentrations the protein stays dissolved and never forms crystals) Left: A bell curve for lysozyme crystals produced in Judge's experiments, and a |
possible shift in the curve that microgravity experiments might produce. Links to 660x440-pixel, 39KB JPG. Credit: NASA/Marshall. The tough part was examining each of the over 2000 wells and counting |
the crystals. It turned out that the solution pH had the largest effect on the growth of the crystals, possibly due to changes in charges on the surface of the |
molecules. When solution conditions had been optimized to give a small number of large crystals, a sample of 50 crystals was withdrawn for X-ray diffraction analysis. Judge hoped that when |
the ideal conditions were found and then applied to subsequent batches, he would be able to grow consistently large, high quality crystals of lysozyme. The expectation was that with ideal |
conditions, quality crystals could be cranked out as if in a factory. Instead, nature put him on the curve. "Some variation is occurring there," Judge said, "but we haven't quite |
pinpointed the cause." Judge got a bell curve when he measured the X-ray clarity, properly called the signal-to-noise ratio (a radio with static has a low signal-to-noise ratio). A graph |
of the number of crystals versus the signal-to-noise ratio forms a bell curve, albeit slightly skewed to one side. Right: Distribution of diffraction characteristics - essentially a measure of quality |
- for a batch of crystals approximates a bell curve. Links to 875x637-pixel, 66KB JPG. Credit: NASA/Marshall. "The distribution is saying a very few crystals form perfectly in solution," he |
continued, "and a small number are really poor. The majority of crystals are in-between." It's doubly puzzling because the crystals were grown from the same batch of lysozyme that was |
poured into 120 wells in the experiment tray and crystallized under the same conditions. "We have some ideas," Judge said, "but we haven't tested them yet, so we're hesitant to |
say it might be this or that." The research will continue with insulin, the crucial protein that conveys sugar from the blood stream into a body's cells, and with glucose |
isomerase, a larger (46,000 Daltons) protein used in industrial processes to convert glucose to a sweeter sugar called fructose. Left: Crystals of insulin grown in space let scientists determine the |
vital enzyme's structure and linkages with much higher resolution that Earth-grown crystals had allowed. Links to 640x448-pixel, 104KB JPG. Larger format versions of these and related images are available from |
the NASA Image Exchange and using the keyword "insulin." Credit: NASA/Marshall. "In all of the proteins we're using the structure is pretty well known," Judge added. In addition to ground-based |
experiments, Judge hopes to conduct flight experiments in the next year or so. He would use the Vapor Diffusion Apparatus, a device developed by the University of Alabama in Birmingham |
and well-proven in a number of Space Shuttle flights. "Most researchers say that crystals grown in microgravity will be better than those on the ground," Judge said. And a number |
of experiments bear out that belief. "Somehow, microgravity pushes up the end of the distribution curve." Right: Crystals of glucose isomerase, a larger molecular weight protein, will be grown to |
see if they, too, are graded "on the curve." Links to 1018x749-pixel, 365KB JPG. Credit: NASA/Marshall. With expected flight experiments on lysozyme, insulin and glucose isomerase, Judge will have crystals |
grown in conditions as close as possible to the ideal conditions he had determined so far. At the same time, he will grow crystals on Earth from the same mix |
as the flight batch and using identical hardware and conditions so that microgravity is the only variable. Eventually, he hopes that his studies will lead to a tool for screening |
candidate proteins for flight. The Effect of Temperature and Solution pH on the Nucleation of Tetragonal Lysozyme Crystals. Biophysics Journal, September 1999, p. 1585-1593, Vol. 77, No. 3 Russell A. |
of Alabama in Huntsville, Huntsville, Alabama 35899; § Biochemistry Department, Michigan State University, East Lansing, Michigan 48825; and ¶Biophysics SD48, NASA/Marshall Space Flight Center, Huntsville, Alabama 35812 USA Part of |
the challenge of macromolecular crystal growth for structure determination is obtaining crystals with a volume suitable for x-ray analysis. In this respect an understanding of the effect of solution conditions |
on macromolecule nucleation rates is advantageous. This study investigated the effects of supersaturation, temperature, and pH on the nucleation rate of tetragonal lysozyme crystals. Batch crystallization plates were prepared at |
given solution concentrations and incubated at set temperatures over 1 week. The number of crystals per well with their size and axial ratios were recorded and correlated with solution conditions. |
Crystal numbers were found to increase with increasing supersaturation and temperature. The most significant variable, however, was pH; crystal numbers changed by two orders of magnitude over the pH range |
4.0-5.2. Crystal size also varied with solution conditions, with the largest crystals obtained at pH 5.2. Having optimized the crystallization conditions, we prepared a batch of crystals under the same |
initial conditions, and 50 of these crystals were analyzed by x-ray diffraction techniques. The results indicate that even under the same crystallization conditions, a marked variation in crystal properties exists. |
More Space Science Headlines - NASA research on the web Life and Microgravity Sciences and Applications information from NASA HQ on science in space Microgravity Research Programs Office headquartered at |
Marshall Space Flight Center Microgravity News online version of NASA's latest in Microgravity advancements, published quarterly. Join our growing list of subscribers - sign up for our express news delivery |
and you will receive a mail message every time we post a new story!!! For more information, please contact:| Dr. John M. Horack , Director of Science Communications Curator: Linda |
Technology Review has a writeup on the latest advance in the lab towards an invisibility cloak made of metamaterials, described this week in Science. We've been following this technology since |
the beginning. The breakthrough is software that lets researchers design materials that are both low-loss and wideband. "The cloak that the researchers built works with wavelengths of light ranging from |
about 1 to 18 gigahertz — a swath as broad as the visible spectrum. No one has yet made a cloaking device that works in the visible spectrum, and those |
metamaterials that have been fabricated tend to work only with narrow bands of light. But a cloak that made an object invisible to light of only one color would not |
be of much use. Similarly, a cloaking device can't afford to be lossy: if it lets just a little bit of light reflect off the object it's supposed to cloak, |
Freshwater Drum - (Aplodinotus grunniens) Length: up to about 14 inches, although it may become quite large in rivers Weight: 5-15 pounds, world record is 54 1/2 pounds Coloring: Gray or silvery in turbid waters, bronze-colored in clearer waters. The head is somewhat darker than the rest of the body; |
the ventral portion of the fish is white. The pectoral and pelvic fins are white, but the rest of the fins are dusky. Common Names: sheepshead, croaker, thunder pumper, lake drum, grunt, bubbler, grinder Found in Lakes: all Great Lakes The freshwater drum is the only member of its family |
that lives entirely in freshwater habitats, and it has the largest native range of any sport fish in the region. Drum are an important commercial crop on the Mississippi River but constitute only a small portion of the commercial perch catch in Lake Michigan. The drum earned part of its |
Latin name, "grunniens" (meaning "grunting"), by its odd grunting noises, which are produced by a special set of muscles located in the body cavity that vibrates against the swim bladder. The purpose of the noise is unknown, but only mature males develop the structure (by the time they reach three |
years of age), suggesting that it is most likely related to spawning. Drums also may croak like bullfrogs when removed from the water, and scientists still don't know if the croaking noise is generated in the same way. Identification of this fish is fairly easy. Drum have two dorsal fins |
that are joined by a narrow membrane. The anterior fin is spiny, and the posterior fin has soft rays. The are the only fish found in Wisconsin with a lateral line that extends through the caudal fin. The drum's otoliths are exceptionally large and look a great deal like ivory. |
In times past they have been worn as protective amulets, made into jewelry, and traded into areas far from the fish's native range (such as Utah and California). Drum are a bottom-dwelling species found in lakes and rivers; they tolerate both clear and turbid conditions. Their diet consists mainly of |
immature insects, crayfish, and minnows, although they may also feed on mollusks. The white, flaky flesh of the drum is tasty and has a low oil content. (nutritional information) When cooking, be sure that the fish doesn't dry out and become hard. The low oil content means that fillets dry |
out much more quickly than other, more oily, fish. Recommended cooking methods include pan frying (in batter) or deep fat frying. Smoking also works well, as long as you're careful not to heat them for too long. Freshwater drum are good fighters and will take bait such as crayfish, minnows, |
and worms. In warm weather they move in schools to shallow waters to feed and possibly spawn (spawning has not been witnessed by scientists). By winter their activity levels and feeding activity are sharply reduced. copyright 2001 University of Wisconsin Sea Grant Institute This page is Bobby Approved. |
Assessing Students' Understanding of Complex Systems Assessing student understanding of complex thinking is quite challenging. As with assessing student learning on any topic, the first step is to identify your learning goals for your students. Once you have identified learning goals, it becomes easier to choose one or... |
possible learning objectives related to students' thinking about complex systems (i.e., skills expected from students who exhibit complex systems thinking). While this is in no way intended to be a comprehensive list of possible learning goals, it may help you to articulate your own list. A student who demonstrates com... |
a complex system - Describe and/or model a process where there is a feedback mechanism at work - Build a model that mimics the expected behavior of the target system - Identify stocks/reservoirs and flows - Correctly identify positive/negative feedbacks - Test a model through trial and error and comparison to real-worl... |
system under different parameters - Bridge across scales: student explanations of processes show fidelity across scales (e.g., a student applies the concept of homeostasis at multiple levels) - Create and interpret graphical information - Predict attributes of system behavior based on specific inputs or components of t... |
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