Monday, November 29, 2010

Feeling Creative?

A misconception about science and scientists that still hangs around is that science is made up of mostly boring, systematic methodology conducted by old, stodgy men in white lab coats. Nothing could be further from the truth, of course.  That's why we've created a new module on Creativity in Science!

This module, written by Barry Bickmore, highlights how creativity and ingenuity play crucial roles in scientific practice. From genetics to DNA recombination, creativity has been an important factor in discovering what we know about the world and all that is in it. It helps us break down complex questions and concepts into digestible chunks, as well as look at a problem from many different angles.

We'd love to hear your thoughts on this module, and suggestions on how to incorporate creativity into everyday scientific practice. Share with us here, or on our Facebook page!

Monday, November 22, 2010

Talking Turkey -- Using Science to Cook the Perfect Bird

We all want it -- a fat, juicy, golden bird on Thanksgiving Day. One that melts in your mouth. One who's flavor explodes and sends you into turkey bliss. One that you can't stop eating because it tastes sooo good and ends up sending you into a slumber on the couch during the afternoon football game (not due to tryptophan, but from a carb-heavy meal).

But how many of us actually get it? How many of us have worked out that seemingly magical combination of basting and cooking times so that we reach this Holy Grail of Turkeydom? Surprisingly, not so many!

Let us help you get a little closer to that dream this year by breaking down some of the science behind roasting the perfect bird.

The first thing to understand is the physiology of our illustrious Meleagris gallopavo. Turkeys are birds, which means that they fly. Right? But, they also spend a lot of time walking about on the ground. As a result, the muscle mass in a turkey's body is pretty much split up into two groups: the breast and the legs.

The breast muscles are located close to the bird's center of gravity, which helps it both flap its wings and control its position in flight. But turkeys don't migrate -- they hang around their home turf all year round. In reality, the heavier percentage of a turkey's lifetime activities are spent on their two little legs, not flying about. Flight is typically reserved for roosting in trees and quick escape from predators. This means that the more heavily used leg muscles are both greater in concentration of fat (because fat is an energy store) and full of blood-enriched tissue (because oxygen is required for energy conversion).

It's this discrepancy in muscle use that accounts for the difference in meat color and texture. The lesser used breast muscles are white and leaner, while the more active leg muscles are a nice dark color with more fat. Wild turkeys and those that are free range will tend to have a higher percentage of dark meat than those birds raised in mass production farms -- mainly because they get more exercise. (This in true for chickens, too, incidentally.)

So what does it matter that the turkey uses its legs more than its wings? It means everything. Muscles are a combination of water, fat, and protein.The fibers within the muscle are primarily protein, and these need to be broken down in order for our bodies to process their goodness. Adding heat to our bird is what breaks down these muscle fibers.

The meat fibers as a whole tend to break down around 180 degrees Fahrenheit, unraveling and making our bird more tender. But if we apply heat for too long, those proteins begin to coagulate and make the bird dry and tough. The trick, here, is that the breast meat and the leg meat have different proportions of water, fat, and protein AND the amount of mass of the sections are different. (The legs are sticking off the body and smaller in size than the breast, right? They aren't going to cook at the same rate.)

What happens if we put our bird in the oven and cook it until the breast meat is a gorgeous 180 degrees Fahrenheit near the bone? The legs are overdone and falling off the bird. And if we cook it until the legs are a perfect 180 degrees? The breast meat is undercooked and tough.

So, how do we get moist, tender breast meat AND moist, tender dark meat?

Tricks for evening cooking time
We want our bird to come out of the oven with everything in a perfect state. In order to accomplish this, we need to accommodate for the cooking differentials explained above. Some will tell you that this means slowing down the cooking of the breast, and speeding up the cooking of the legs because dark meat takes longer -- but that ignores the fact that the legs are smaller in overall size than the breast. Though pound for pound leg meat will take longer to cook than breast, overall there is less leg meat on your Thanksgiving bird.

So what do we do?

Chef Iain Falconer of Olive's in NYC does NOT recommend putting ice packs on your turkey's breast for the hours leading up to the roasting, as you might read elsewhere. By cooling the meat down considerably, and letting the legs stay at room temperature, the time it takes for the breast meat to warm to cooking temperature will give the legs too much of a head start. Cooling the legs is a better idea, though not very practical. Instead, cover the turkey's legs with aluminum foil. The foil reflects the oven's heat significantly enough to create a temperature difference between the two parts of the bird. Take the foil off somewhere at the start of the last hour to get a beautiful color on the skin.

How long in the oven?
Once you've established that temperature difference in the muscle tissue, it's time to put your bird in the oven. Add some water or broth to the pan to stimulate steaming (and thus juiciness), then pop it in at 475 degrees Fahrenheit for 15 minutes. Starting high will cause the heat to hit your bird's skin first, which will force the fat to melt and the protein to unravel, then coagulate to form a nice crispy outer cover.

After 15 minutes, reduce the cooking temperature to 375 degrees and cook according to the weight of your bird. A turkey's perfect cooking time is 15 to 20 minutes per pound of weight, plus an extra 15 to 20 minutes at the end. If your bird is small, aim toward 20 minutes per pound; larger birds, aim toward 15 minutes. (This may seem illogical at first, but a smaller bird will be in the oven less time overall than the larger, so you'll need the little bit of extra time to make sure it's all cooked and the proteins are unraveled.)

When the breast meat has reached 180 degrees, all bacteria will have been killed. Your juices should run clear, and you can leave the bird to rest outside of the oven for 20 minutes to cool and reabsorb that moisture back into the meat. Cutting while fresh out of the oven will send the good juice into the gravy and not into the muscle fibers, leaving Tom the Turkey dry.

To stuff or not to stuff, that is the question
When a turkey is prepared for roasting, what is in its center? Nothing -- it's empty. Empty except for the various bacteria, like Salmonella, that tend to thrive on raw poultry products. If you then put stuffing into that cavity, you not only increase the overall mass of the bird, you create a wonderful haven for those bacteria to have their own little Thanksgiving party.

In order to raise the inner cavity (the stuffing) to the bacteria-killing temperature of 180 degrees Fahrenheit, you're going to need to roast that bird for a lot longer than the times described above. Which will result in what? You got it -- tough, dry, chewy turkey. Exactly what we're trying to avoid.

So, if you want that wonderful flavor of the bird infused into your 'stuffing', don't put it into the bird. Instead, use some of the juices from the cooking process to add flavor. If you're a bread stuffing fan, skip the water and use the juices to moisten that bread.

Have some tricks of your own you would like to share for a perfect Thanksgiving Feast? Share them with us on our Facebook page, or in the comments section below!

Tuesday, November 9, 2010

Surprise Discovery in the Milky Way

It seems that whenever we think we know something well, we're proven wrong. As was announced through a press release from NASA today, NASA's Fermi Gamma-ray Space Telescope has unveiled a previously unseen structure centered in the Milky Way. The feature spans 50,000 light-years and may be the remnant of an eruption from a super-sized black hole at the center of our galaxy.

"What we see are two gamma-ray-emitting bubbles that extend 25,000 light-years north and south of the galactic center," said Doug Finkbeiner, an astronomer at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., who first recognized the feature. "We don't fully understand their nature or origin."

The structure spans more than half of the visible sky, from the constellation Virgo to the constellation Grus, and it may be millions of years old. A paper about the findings has been accepted for publication in The Astrophysical Journal.

Finkbeiner and Harvard graduate students Meng Su and Tracy Slatyer discovered the bubbles by processing publicly available data from Fermi's Large Area Telescope (LAT). The LAT is the most sensitive and highest-resolution gamma-ray detector ever launched. Gamma rays are the highest-energy form of light.

Other astronomers studying gamma rays hadn't detected the bubbles partly because of a fog of gamma rays that appears throughout the sky. The fog happens when particles moving near the speed of light interact with light and interstellar gas in the Milky Way. The LAT team constantly refines models to uncover new gamma-ray sources obscured by this so-called diffuse emission. By using various estimates of the fog, Finkbeiner and his colleagues were able to isolate it from the LAT data and unveil the giant bubbles.

Scientists now are conducting more analyses to better understand how the never-before-seen structure was formed. The bubble emissions are much more energetic than the gamma-ray fog seen elsewhere in the Milky Way. The bubbles also appear to have well-defined edges. The structure's shape and emissions suggest it was formed as a result of a large and relatively rapid energy release -- the source of which remains a mystery.

One possibility includes a particle jet from the supermassive black hole at the galactic center. In many other galaxies, astronomers see fast particle jets powered by matter falling toward a central black hole. While there is no evidence the Milky Way's black hole has such a jet today, it may have in the past. The bubbles also may have formed as a result of gas outflows from a burst of star formation, perhaps the one that produced many massive star clusters in the Milky Way's center several million years ago.

"In other galaxies, we see that starbursts can drive enormous gas outflows," said David Spergel, a scientist at Princeton University in New Jersey. "Whatever the energy source behind these huge bubbles may be, it is connected to many deep questions in astrophysics."

Hints of the bubbles appear in earlier spacecraft data. X-ray observations from the German-led Roentgen Satellite suggested subtle evidence for bubble edges close to the galactic center, or in the same orientation as the Milky Way. NASA's Wilkinson Microwave Anisotropy Probe detected an excess of radio signals at the position of the gamma-ray bubbles.

The Fermi LAT team also revealed Tuesday the instrument's best picture of the gamma-ray sky, the result of two years of data collection.

"Fermi scans the entire sky every three hours, and as the mission continues and our exposure deepens, we see the extreme universe in progressively greater detail," said Julie McEnery, Fermi project scientist at NASA's Goddard Space Flight Center in Greenbelt, Md.
NASA's Fermi is an astrophysics and particle physics partnership, developed in collaboration with the U.S. Department of Energy, with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden and the United States.

"Since its launch in June 2008, Fermi repeatedly has proven itself to be a frontier facility, giving us new insights ranging from the nature of space-time to the first observations of a gamma-ray nova," said Jon Morse, Astrophysics Division director at NASA Headquarters in Washington. "These latest discoveries continue to demonstrate Fermi's outstanding performance."

Monday, November 1, 2010

Engaging Students in Research

One of the main tasks of any graduate student in the STEM fields, Masters or Doctorate, is engaging in research. It goes without saying that a significant amount of time during matriculation will be spent in the lab or field working on hypotheses and hoping to contribute something new to their respective discipline. But where do these students learn their skills to begin with? And with such low completion rates in STEM disciplines, how to do we get undergraduate students to stick around long enough to learn what they need to go onto and succeed in graduate school?

Across the country, undergraduate research programs have been growing and proving to be an effective way of retaining students. It's had such an effect that President Obama called it out directly in his speech to the National Academies of Sciences. These mentoring programs have proven to teach students the basic physical and rationalization skills they need to pursue advanced degrees, better preparing them for the work ahead.

But a question that has yet to be answered, which we throw out to you, is how to engage undergraduate students in research to begin with? As Eagan et al. highlight in their report, Engaging Undergraduates in Science Research:

"Students who initially enter college with the intention of majoring in science, technology, engineering, or mathematics (STEM) fields have substantially lower completion rates in these disciplines than do their peers who enter with aspirations for a non-STEM major (Huang, Taddese, & Walter, 2000). Compounding this problem, under-represented racial minority (URM) students in STEM have extremely low bachelor’s degree completion rates, especially when compared with their White and Asian American counterparts. A Higher Education Research Institute (HERI) report indicated that just 24.5% of White students and 32.4% of Asian American students who entered college with the intention of majoring in a STEM field completed a bachelor’s degree in STEM within four years while 15.9% of Latino, 13.2% of Black, and 14.0% of Native American students did the same (HERI, 2010)."

So, how do we catch these students who tend to fall through the cracks, who may not understand what research can do for their future? What can we do to make sure they enroll in available programs and increase the retention rates of under-represented groups?

Share your ideas with us here, or on our Facebook page. we'd love to know what you're doing (or think could be done) to get and keep more students in STEM courses.