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98.6 Degrees F, It’s The Perfect Temperature

98.6 degrees Fahrenheit (37 degree Celsius), that’s the number we all have learnt right since our childhood as the normal human body temperature, and anything above or below indicates that something is wrong with our body. This particular temperature (with slight fluctuations) is our normal temperature set point which our body tries to maintain. Fahrenheit initially designed the temperature scale with human body temperature as reference point and defined it to be 100°F, but later the reference point was changed to boiling point of water (100°C). Later in 1861, Carl Reinhold measured mean temperature of a healthy human body to be 98.6°F (or 37°C). Currently, most accurate number is 98.2°F (or 36.8°C) . Our brain regulates temperature of our body and keeps it regulated at the set point, which is very important for various chemical reactions to occur inside our body. Fever is defined as that state of body when the temperature set point is raised due to different causes while hyperthermia is defined as the state of body when temperature of the body increases without any increase in set point temperature (heat-stroke).

But why 98.6 degrees, why such a high temperature which is an energy intensive and costly affair. The answer lies in the cost and benefits of having high body temperature. Recent study by researchers at Albert Einstein College of Medicine have shown that per degree increase in body temperature reduces the number of fungi species which can infect the animal by about 6%. Thus by having high body temperatures, mammals have minimized the chances of getting infected and increased the survival rate at the cost of more energy intake. In a recent study, Dr. Casadevall  and Aviv Bergman have developed a simplistic first order mathematical model to estimate the optimum temperature considering the trade-off between metabolic costs incurred and benefits obtained in the form of increased resistance. The metabolic rate function is defined as B which is a function of body mass (m), while the benefit function is defined as F which is a function of rate of reduction in number of fungal species capable of infecting the animal (s~ 6% per degree rise in temperature based on earlier study).

Using these two functions, the fitness curve was plotted against body temperature and optimum T was found to be 36.7 °C or 98.06 °F!

You can access the full paper here.

Image credit: Flickr user Josh md | Used under creative commons license

Article and plot credit: Aviv Bergman and Arturo Casadevall: Mammalian Endothermy Optimally Restricts Fungi and Metabolic Costs, mBio 2010. doi:10.1128/mBio.00212-10

Leave a Comment December 29, 2010

Eight Year Olds Publish Bee Study In Biology Letters

It’s not everyday that you are going to come across a peer-reviewed research article published by bunch of cool and smart eight year old kids. In last week’s early online edition of Biology Letters a new study has been published by 25 eight-to-ten-year old kids from Blackawton primary school in UK.  The study reports about how bumble bees use different color and pattern identification strategies to determine which flower to choose for getting nectar and which ones to avoid. What’s unique about this study is that the kids came up with the questions they wanted to study and then they designed the experiments themselves and did the data analysis (ofcourse under supervision and guidance of their teachers and neuroscientist Dr R.B. Lotto of the lottolab). The article is fully written by children in their own language (except the abstract) and cites no references. Lack of any references made it difficult to get published in peer-reviewed journal initially but the authors of the paper insisted that the it was not the historical studies which made them do the study, rather it was their own interest, curiosity and observations which prompted them to carry out the study. The article is not only informative but fun to read. You will rarely see sentences such as “We also discovered that science is cool and fun because you get to do stuff that no one has ever done before” in a research article. Figures and tables are hand-drawn and one of the section title has also got some sound effects “Training phase 2 (‘the puzzle’ . . .duh duh duuuuhhh)”. But the article is not just about the cuteness but it has got some serious scientific observations.  As the authors themselves point out in the article that This experiment is important, because, as far as we know, no one in history (including adults) has done this experiment before.” The experiments are very sound, well thought of and results are well discussed and most of all after reading the paper you can get the feeling how much the kids enjoyed doing this study and how proud they are of their findings. I will summarize their findings here but I will also recommend all of you to go and read the article, I am sure it will motivate the kid inside you to ask some basic scientific questions and make you do some funful research! The article is available for free until new year eve.

The main question which young scientists wanted to investigate was if bumblebees can solve the complex puzzle of identifying color or spatial patterns in a complex scenario and if they can learn to find the “good flower” based on these cues. “It is interesting to ask this question, because in their habitat there may be flowers that are bad for them, or flowers from which they might already have collected nectar. This would mean that it is important for bees to learn which flower to go to or to avoid” (quoted from the article).

They designed a Plexiglass bee arena (1 m cube) with four panels as shown above. Each panel consisted of two color patterns and at the center of each colored-circle, there was a tube feeder which either consisted of sugar water, salty water or no water. The bees were first trained with the above pattern where sugar water was present all the time in the 4-center colors (either blue or yellow), while salty water  was present in the surrounding colors. This pattern kind of crudely represented a two color flower pattern. If the bees chose a random strategy, then 50% of times , they will encounter salty or sugary water; same will happen if they chose to follow a particular color. But if they were able to learn the color pattern to identify the sugar water, they will be more successful in getting the sweet water. In order to eliminate any bias due to any odor preference or contamination, the trained bees were let to choose the circles without any salt or sugar water in the feeders.

You can see from the tabulated results that about 90% of bees learnt the color patterns and chose to go to center feeders. The notations O,Y,B/Y, B etc are for identifying the individual bees which were marked as Orange, yellow, Blue Yellow and so on. As the article reports, somehow the yellow marked bee never came out of the bee arena and that explains why there is no data for the Y bee!

In second set of experiments, they maintained the two color pattern, but changed the central four colors to be green while the surrounding colors were changed to either yellow or blue. The purpose of this was to see if bees went to the central circles due to spatial preference or due to pattern learning process. When the central colors were changed to green, only 30.9% of the bees went to the central circles, implying that the pattern cues also play an important role for bees in identifying the right flower, not just the spatial cues. It also showed that it was not just the color or the spatial location, but the overall pattern cues which bees utilize in making decisions. Some of the bees also preferred to go to their favorite colors. Overall, the findings suggest that bumblebees employ a complex strategy of pattern and spatial cues in identifying the right flowers and they can memorize these patterns which helps them in deciding between the “right” vs “wrong” flower. Young researchers in this paper also say that ” bees have personality and have their personal ‘likings’.” The article concludes with the following paragraph:

Before doing these experiments we did not really think a lot about bees and how they are as smart as us. We also did not think about the fact that without bees we would not survive, because bees keep the flowers going. So it is important to understand bees. We discovered how fun it was to train bees. This is also cool because you do not get to train bees everyday. We like bees. Science is cool and fun because you get to do stuff that no one has ever done before. (Bees—seem to—think!)

Well done kids and along with your bee study results, I agree with one of your other important discovery– Science is cool and fun— Yes it is for sure!

Image credit: 1) Flickr user Ian Kirk, 2) Pattern, Data table: Biology Letters and Authors of the article.

Article: Blackawton bees; Blackawton, P. S. et al. Biol. Lett. doi:10.1098/rsbl.2010.1056

Also read commentary on the article by Laurence T. Maloney, and Natalie Hempel de Ibarra

Leave a Comment December 27, 2010

LIBS Focal Point Article

If you work in the field of Laser-induced Breakdown Spectroscopy (LIBS) or plan to work in future, you have to read the latest focal point article in Applied Spectroscopy by two experts in the field, David Hahn and Nicolo Omenetto from University of Florida. It’s an excellent article (32 pages, 280 references) which reviews various fundamental studies in LIBS until now and questions certain fundamental issues (Local Thermodynamic Equilibrium assumption, spatial homogeneity of the plasma etc) which need to be clearly understood and resolved by the LIBS community in order to make LIBS a well established analytical technique. This is first in series of 2-set focal point articles on LIBS. I am in the process of reading the article and will update my blog once I have finished reading the article. You can access the full article here. It was decided by Society for Applied Spectroscopy during the FACSS 2010 meeting that all the focal point articles in Applied Spectroscopy will be available for free to all the readers. All the focal point articles since 1994 will be soon available on the SAS and ingentaconnect website pretty soon. The abstract of the LIBS article is as follows:

Laser-Induced Breakdown Spectroscopy (LIBS), Part I: Review of Basic Diagnostics and Plasma-Particle Interactions: Still-Challenging Issues Within the Analytical Plasma Community

Authors: Hahn, David W.; Omenetto, Nicoló

Source: Applied Spectroscopy, Volume 64, Issue 12, Pages 318A-366A and 1311-1452 (December 2010) , pp. 335A-366A(32)

DOI: 10.1366/000370210793561691

Abstract:

Laser-induced breakdown spectroscopy (LIBS) has become a very popular analytical method in the last decade in view of some of its unique features such as applicability to any type of sample, practically no sample preparation, remote sensing capability, and speed of analysis. The technique has a remarkably wide applicability in many fields, and the number of applications is still growing. From an analytical point of view, the quantitative aspects of LIBS may be considered its Achilles’ heel, first due to the complex nature of the laser-sample interaction processes, which depend upon both the laser characteristics and the sample material properties, and second due to the plasma-particle interaction processes, which are space and time dependent. Together, these may cause undesirable matrix effects. Ways of alleviating these problems rely upon the description of the plasma excitation-ionization processes through the use of classical equilibrium relations and therefore on the assumption that the laser-induced plasma is in local thermodynamic equilibrium (LTE). Even in this case, the transient nature of the plasma and its spatial inhomogeneity need to be considered and overcome in order to justify the theoretical assumptions made. This first article focuses on the basic diagnostics aspects and presents a review of the past and recent LIBS literature pertinent to this topic. Previous research on non-laser-based plasma literature, and the resulting knowledge, is also emphasized. The aim is, on one hand, to make the readers aware of such knowledge and on the other hand to trigger the interest of the LIBS community, as well as the larger analytical plasma community, in attempting some diagnostic approaches that have not yet been fully exploited in LIBS.
Image Credit: Applied Spectroscopy, Ingenta Connect, Authors of the article

Abstract:

Laser-induced breakdown spectroscopy (LIBS) has become a very popular analytical method in the last decade in view of some of its unique features such as applicability to any type of sample, practically no sample preparation, remote sensing capability, and speed of analysis. The technique has a remarkably wide applicability in many fields, and the number of applications is still growing. From an analytical point of view, the quantitative aspects of LIBS may be considered its Achilles’ heel, first due to the complex nature of the laser-sample interaction processes, which depend upon both the laser characteristics and the sample material properties, and second due to the plasma-particle interaction processes, which are space and time dependent. Together, these may cause undesirable matrix effects. Ways of alleviating these problems rely upon the description of the plasma excitation-ionization processes through the use of classical equilibrium relations and therefore on the assumption that the laser-induced plasma is in local thermodynamic equilibrium (LTE). Even in this case, the transient nature of the plasma and its spatial inhomogeneity need to be considered and overcome in order to justify the theoretical assumptions made. This first article focuses on the basic diagnostics aspects and presents a review of the past and recent LIBS literature pertinent to this topic. Previous research on non-laser-based plasma literature, and the resulting knowledge, is also emphasized. The aim is, on one hand, to make the readers aware of such knowledge and on the other hand to trigger the interest of the LIBS community, as well as the larger analytical plasma community, in attempting some diagnostic approaches that have not yet been fully exploited in LIBS.

Leave a Comment December 11, 2010

Recipe For Hope Campaign

After a long break from blogging, I am back! During this break, I visited my family in India and as always the trip was awesome. Getting back to blogging, there’s lots of catching up to be done as lots have happened in the science world over the past month. Without any further delay lets get started.

During the past few years lots of research has been done in understanding Autism, but still lots more to be done and good research needs funding. Along with research, its also important to raise awareness about autism spectrum related disorders and help out families affected by autism. Autism Science Foundation aims to achieve these objectives and needs support of generous donors. During this season of giving, you have got an opportunity to be part of Autism Science Foundation’s RecipeForHope campaign. Visit their website and helpout in whatever way you can. Happy Giving!!

http://www.recipe4hope.org/

Leave a Comment December 10, 2010

29th Annual AAAR Conference, Portland

I will be traveling to Portland, Oregon all of next week for attending American Association for Aerosol Research Conference. This will be my first time attending this conference and as I am relatively new to the aerosol community, this will be a great opportunity for me to learn some new stuff in aerosol characterization and measurement methods. I will also be presenting my work on elemental characterization of fine and ultra-fine aerosols using Laser-induced Breakdown spectroscopy. If you are interested, here are the abstracts of my oral presentation and poster presentation. (shameless self promotion :))

Leave a Comment October 21, 2010

Molecule Makers Win 2010 Nobel Prize in Chemistry

Three scientists, Richard F. Heck, Ei-ichi Negishi and Akira Suzuki, share this year’s Nobel prize in Chemistry “for palladium-catalyzed cross couplings in organic synthesis”. Carbon-to-Carbon molecules form the backbone of life on Earth. While the presence of such molecules on earth is ubiquitous, synthesizing such a molecule in lab is not that easy as Carbon is very stable and doesn’t react easily with other Carbon to form bond. The trio,while working independently, have come up with chemical reactions where such molecules can be synthesized using Palladium as a catalyst.

Palladium-catalyzed cross coupling solved that problem and provided chemists with a more precise and efficient tool to work with. In the Heck reaction, Negishi reaction and Suzuki reaction, carbon atoms meet on a palladium atom, whereupon their proximity to one another kick-starts the chemical reaction. Palladium-catalyzed cross coupling is used in research worldwide, as well as in the commercial production of for example pharmaceuticals and molecules used in the electronics industry. [Nobelprize.org

I will add more information about their work later during the day.

2 Comments October 6, 2010

How Hot Was Summer 2010?

Summer of 2010 has experienced some extremely severe temperatures and drought like conditions especially in Eastern Europe, Russia and in some parts of Eastern USA. So how hot was summer of 2010? Was it the hottest summer globally or hot summers of Russia were more of local anomalies? NASA GISS has come up with analysis of measured temperature during Jun-Aug 2010 and can be seen in the above plot. The plot shows temperature anomalies as compared to base average temperature during 1951-1980. From the plot, its clearly seen that two region in the globe experienced severe hot summers namely Eurasia region and Antarctic Peninsula. So how were these temperature anomalies as compared to last year, lets have a look:

As can be seen from the 2009 temperatures, severe temperature anomalies like summers of Russia were not there in 2009. But what does that mean in terms of Global temperature trend, which was hotter: summer of 2009 or 2010?

Globally, 2010 was the 4th warmest summer in GISS’s 131-year-temperature record. The summer of 2009 was the 2nd warmest. The slightly cooler 2010 temperatures were primarily the result of a moderate La Niña replacing a moderate El Niño in the Pacific Ocean. Note in 2010 that much of the eastern Pacific, the west coasts of North and South America, and much of Antarctica were cooler than the long-term mean. Temperatures were extremely warm in western Russia and the Antarctic Peninsula. The unusually warm summer temperatures in the U.S. and Eurasia created the impression of global warming run amuck; last winter’s unusually cool temperatures created the opposite impression. But extrapolating global trends based on one or two regions can be misleading.

“Unfortunately, it is common for the public to take their most recent local temperature anomaly as indicative of long-term climate trends, ” James Hansen from NASA GISS noted. “People need to understand that the temperature anomaly in one place in one season has limited relevance to global trends. ” [NASA ESO]

So what it implies is that summer of 2010 was hot but it’s severity was dependent on where you lived. It also means that local temperature anomaly has limited relevance to global temperature trends. But that doesn’t  imply that extreme local temperature absurdities have nothing to do with global temperature trends but before jumping to any conclusions one has to look into long term statistics and trends. If we take a look at average data of past 10 years or so, we might see ups and downs in temperatures but in a long run there is a clear trend of temperature rise.

Data and Analysis credit: NASA ESO | GISS

Leave a Comment September 30, 2010

Earth-like Exoplanet Found 20 Light Years Away

Astronomers have found an exoplanet, Gliese 581g, 20 light years away from us which might have right conditions for sustaining life or in other words might be possibly habitable. In recent years study of exoplanets have gained lots of momentum to find earth-sun like systems. Till now there are around 500 known exoplanets and more will be discovered in near future. The exoplanet system mentioned here consists of a  red dwarf star  Gliese 581 which is about 20.5 light years away from earth. Till now six planets have been discovered in this system which has remarkably close to circular orbits like our solar system. So what makes the discovery of this planet, Gliese 581g, so remarkable? Well, it’s one of the exoplanets discovered which is believed to lie in Goldilocks zone or habitable zone where liquid water might exist.

In order for life to exist, the planet must neither be too far nor too near form it’s sun. It must have sufficient gravity to hold the atmosphere and regulate the temperature of the planet. Gliese 581 star-planet system have received lots of attention in recent years and other planets from the system have also been in such discussion. Here you can see the G581 planet-sun system showing the possible orbits of all the six planets as compared to our solar system which are shown in dotted lines. The blue one is earth’s orbit, while green and red are Venus and Mercury. What’s interesting to observe is  the circular nature of orbits and its close similarity to our solar system.  The fourth black orbit from the center is the planet under discussion in this article. AU in the plot represents Astronomical Units which is equal to distance of sun from earth.

Some other details about this exoplanet. The mass of the planet is about 3.1 times the mass of earth and orbits in 36.6 days at a distance of 0.146 AU from it’s sun. This distance is pretty close if it was our Sun, but this particular star is less bright than our sun, just 1% as bright as our Sun, so this distance is perfect to make it neither too hot or cold. 3 times the mass of earth implies, that the planet has sufficient density to hold the atmosphere which would in turn retain greenhouse gases for regulating the temperature. One thing to note here is that measurements were done using Doppler shift method which due to technique limitations can only give a lower limit on the size and mass of the planet, so this planet can be much more bigger than 3 times mass of earth. Larger mass is good to hold atmosphere but too large a size can create a very dense atmosphere and heat up the planet extensively, case in point Venus. The astronomers estimated average surface temperature based on the size, density, distance from sun etc and estimated it be in the range of 236-258K , which is pretty good. Overall, an interesting finding and a very exciting exoplanet system to study and understand in near future.

Article:The Lick-Carnegie Exoplanet Survey: A 3.1 M_Earth Planet in the Habitable Zone of the Nearby M3V Star Gliese 581, arXiv:1009.5733v1[astro-ph.EP]

Plot credit:Authors of the article, arXiv.org

Picture credit:Wikimedia Commons- Compariosn of Gliese Exoplanet system with Earth and Neptune

1 Comment September 30, 2010

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