Be careful microwaving water!!!

The Scenario: A man decided to have a quick cup of coffee. He places a cup of water in a microwave oven to heat it up (something he has done numerous times before). When the timer shut the oven off, he removed the cup from the oven. As he was about to add the coffee granules to the hot water, he noticed the water did not appear to
be boiling, but suddenly the water “blew up” into his face scalding him.
Why did this happen?

The water actually became “superheated.” Water boils at 100 degrees Celsius at normal atmospheric pressure but in a microwave oven it can be superheated without tell tale bubbles appearing. If a litre of water is superheated by only 1 degree, it is in an unstable state and can suddenly produce about 3 litres of steam while quickly returning to boiling point.
The following conditions promote this potentially dangerous event:- Using a container with a very smooth surface, such as an unscratched glass or glazed container; heating for too long; or quickly adding a substance such as coffee granules or even a spoon. Even a jarring action can cause it to “explode.”
How to avoid it:
• The best advice is not to heat water in a microwave oven. Use an electric jug or kettle or a saucepan on a stove.
• Before putting the water into the oven, insert a non-metal object with a surface that is not smooth. (e.g. a wooden stirrer).
• Use a container, the surface of which is at least a little scratched or not new.
• Do not heat for longer than the recommended time for the quantity of water used.
• Tap the outside of the container with a solid object while it is still in the microwave oven.
An explanation:

In a microwave oven, the water is usually hotter than the container, whereas parts of a kettle or saucepan are usually hotter than the water. Further, the surfaces of some containers used in microwave ovens may be very smooth, almost at a molecular scale, whereas this is not true for kettles or saucepans.
Microwave ovens heat the water directly: the microwaves pass through the container and the water, and the water itself absorbs energy from them. The container absorbs little energy directly. In a kettle or saucepan, the container itself (saucepan) or a heating element (some kettles) is hotter than the water. The hottest points cause a small amount of local superheating, boiling is initiated here, and this then stirs the water.

Received & published by Henry Sapiecha

New Understanding of Bizarre

Extinct Mammal:

Shares Common Ancestor

With Rodents, Primates

Science(Oct. 11, 2010) — University of Florida researchers presenting new fossil evidence of an exceptionally well-preserved 55-million-year-old North American mammal have found it shares a common ancestor with rodents and primates, including humans.

The study, scheduled to appear in the Oct. 11 online edition of the Zoological Journal of the Linnean Society, describes the cranial anatomy of the extinct mammal, Labidolemur kayi. High resolution CT scans of the specimens allowed researchers to study minute details in the skull, including bone structures smaller than one-tenth of a millimeter. Similarities in bone features with other mammals show L. kayi‘s living relatives are rodents, rabbits, flying lemurs, tree shrews and primates.

Researchers said the new information will aide future studies to better understand the origin of primates.

“The specimens are among the only skulls of apatemyids known that aren’t squashed completely flat,” said study co-author Jonathan Bloch, an associate curator of vertebrate paleontology at the Florida Museum of Natural History on the UF campus. “They’re preserved in three dimensions, which allows us to look at the morphology of the bones in a way that we never could before.”

Scientists have disputed the relationships of Apatemyidae, the family that includes L. kayi, for more than a century because of their unusual physical characteristics. With can opener-shaped upper front teeth and two unusually long fingers, apatemyids have been compared to a variety of animals, from opossums to woodpeckers.

“There are only a few examples in the history of mammals where you get such an incredibly odd ecological adaptation,” Bloch said.

Like a woodpecker’s method of feeding, L. kayi used percussive foraging, or tapping on trees, to locate insects. It stood less than a foot tall, was capable of jumping between trees and looked like a squirrel with a couple of really long fingers, similar to the aye-aye, a lemur native to Madagascar, Bloch said.

Apatemyids have been preserved for tens of millions of years and are well known from Europe and North America.

The skeletons analyzed in the publication were recovered from freshwater limestone in the Bighorn Basin by co-author Peter Houde of New Mexico State University. Located just east of Yellowstone National Park in Wyoming, the site is known as one of the best in the world for studying the evolution of mammals during the 10 million years following the extinction of the dinosaurs, Bloch said.

Mary Silcox, first author of the study and a research associate at the Florida Museum, said scans of the specimens began about 10 years ago, during her postdoctoral work at The Pennsylvania State University.

“It’s not like medical CT, it’s actually an industrial CT scanner,” said Silcox, an assistant professor of anthropology at the University of Toronto Scarborough. “Because this is a small animal, we needed to be able to study it at a very high resolution. The high resolution CT data were a critical part.”

Doug Boyer of Stony Brook University is also a co-author of the study, part of the team’s larger research to understand the relationships of apatemyids to other mammals. Bloch and colleagues are currently writing a detailed analysis of L. kayi‘s skeleton.

John Wible, curator of mammals at the Carnegie Museum of Natural History and one of the researchers who reviewed the study, said it provides valuable information for understanding the evolutionary relationships of mammals.

“It is now clear that any assessment of the origins of primates in the future will have to include apatemyids,” Wible said. “Apatemyids are not some freakish dead-end, but significant members of our own history.”

Sourced & published by Henry Sapiecha

Cell Phone Viruses

Pose Serious Threat, Scientists Warn

Science (May 22, 2009) — If you own a computer, chances are you have experienced the aftermath of a nasty virus at some point. In contrast, there have been no major outbreaks of mobile phone viral infection, despite the fact that over 80 percent of Americans now use these devices. A team headed by Albert-Laszlo Barabasi, director of the Center for Complex Network Research at Northeastern University, set out to explain why this is true.

The researchers used calling and mobility data from over six million anonymous mobile phone users to create a comprehensive picture of the threat mobile phone viruses pose to users. The results of this study, published in the May 22 issue of Science, indicate that a highly fragmented market share has effectively hindered outbreaks thus far. Further, their work predicts that viruses will pose a serious threat once a single mobile operating system’s market share grows sufficiently large. This event may not be far off, given the 150 percent annual growth rate of smart phones.

“We haven’t had a problem so far because only phones with operating systems, so-called ‘smart phones’, are susceptible to viral infection,” explained Marta Gonzalez, one of the authors of the publication. “Once a single operating system becomes common, we could potentially see outbreaks of epidemic proportion because a mobile phone virus can spread by two mechanisms: a Bluetooth virus can infect all Bluetooth-activated phones in a 10-30 meter radius, while Multimedia Messaging System (MMS) virus, like many computer viruses, spreads using the address book of the device. Not surprisingly, hybrid viruses, which can infect via both routes, pose the most significant danger.”

This study builds upon earlier research by the same group, which used mobile phone data to create a predictive model of human mobility patterns. The current work used this model to simulate Bluetooth virus infection scenarios, finding that Bluetooth viruses will eventually infect all susceptible handsets, but the rate is slow, being limited by human behavioral patterns. This characteristic suggests there should be sufficient time to deploy countermeasures such as antiviral software to prevent major Bluetooth outbreaks. In contrast, spread of MMS viruses is not restricted by human behavioral patterns, however spread of these types of viruses are constrained because the number of susceptible devices is currently much smaller.

As our world becomes increasingly connected we face unprecedented challenges. Studies such as this one, categorized as computational social science, are necessary to understand group behavior and organization, assess potential threats, and develop solutions to the issues faced by our ever-changing society.

“This is what statistical analysis of complex systems is all about: finding patterns in nature,” said Gonzalez. “This research is vital because it puts a huge amount of data into the service of science.”

Sourced & published by Henry Sapiecha

Tracking Device Fits on the Head of a

Pin: Mini-Gyroscopes to Guide

Smartphones and Medical Equipment

Science (Oct. 8, 2010) — University of Illinois chemistry professor Alexander Scheeline wants to see high school students using their cell phones in class. Not for texting or surfing the Web, but as an analytical chemistry instrument.

Scheeline developed a method using a few basic, inexpensive supplies and a digital camera to build a spectrometer, an important basic chemistry instrument. Spectrophotometry is one of the most widely used means for identifying and quantifying materials in both physical and biological sciences.

“If we want to measure the amount of protein in meat, or water in grain, or iron in blood, it’s done by spectrophotometry,” Scheeline said.

Many schools have a very limited budget for instruments and supplies, making spectrometers cost-prohibitive for science classrooms. Even when a device is available, students fail to learn the analytical chemistry principles inherent in the instrument because most commercially available devices are enclosed boxes. Students simply insert samples and record the numbers the box outputs without learning the context or thinking critically about the process.

“Science is basically about using your senses to see things — it’s just that we’ve got so much technology that now it’s all hidden,” Scheeline said.

“The student gets the impression that a measurement is something that goes on inside a box and it’s completely inaccessible, not understandable — the purview of expert engineers,” he said. “That’s not what you want them to learn. In order to get across the idea, ‘I can do it, and I can see it, and I can understand it,’ they’ve go to build the instrument themselves. ”

So Scheeline set out to build a basic spectrometer that was not only simple and inexpensive but also open so that students could see its workings and play with its components, encouraging critical-thinking and problem-solving skills. It wouldn’t have to be the most sensitive or accurate instrument — in fact, he hoped that obvious shortcomings of the device would reinforce students’ understanding of its workings.

“If you’re trying to teach someone an instrument’s limitations, it’s a lot easier to teach them when they’re blatant than when they’re subtle. Everything goes wrong out in the open,” he said.

In a spectrometer, white light shines through a sample solution. The solution absorbs certain wavelengths of light. A diffraction grating then spreads the light into its color spectrum like a prism. Analyzing that spectrum can tell chemists about the properties of the sample.

For a light source, Scheeline used a single light-emitting diode (LED) powered by a 3-volt battery, the kind used in key fobs to remotely unlock a car. Diffraction gratings and cuvettes, the small, clear repositories to hold sample solutions, are readily available from scientific supply companies for a few cents each. The entire setup cost less than $3. The limiting factor seemed to be in the light sensor, or photodetector, to capture the spectrum for analysis.

“All of a sudden this light bulb went off in my head: a photodetector that everybody already has! Almost everybody has a cell phone, and almost all phones have a camera,” Scheeline said. “I realized, if you can get the picture into the computer, it’s only software that keeps you from building a cheap spectrophotometer.”

To remove that obstacle, he wrote a software program to analyze spectra captured in JPEG photo files and made it freely accessible online, along with its source code and instructions to students and teachers for assembling and using the cell-phone spectrometer. It can be accessed through the Analytical Sciences Digital Library.

Scheeline has used his cell-phone spectrometers in several classroom settings. His first classroom trial was with students in Hanoi, Vietnam, as part of a 2009 exchange teaching program Scheeline and several other U. of I. chemistry professors participated in. Although the students had no prior instrumentation experience, they greeted the cell-phone spectrometers with enthusiasm.

In the United States, Scheeline used cell-phone spectrometers in an Atlanta high school science program in the summers of 2009 and 2010. By the end of the 45-minute class, Scheeline was delighted to find students grasping chemistry concepts that seemed to elude students in similar programs using only textbooks. For example, one student inquired about the camera’s sensitivity to light in the room and how that might affect its ability to read the spectrum.

“And I said, ‘You’ve discovered a problem inherent in all spectrometers: stray light.’ I have been struggling ever since I started teaching to get across to university students the concept of stray light and what a problem it is, and here was a high school kid who picked it right up because it was in front of her face!” Scheeline said.

Scheeline has also shared his low-cost instrument with those most likely to benefit: high school teachers. Teachers participating in the U. of I. EnLiST program, a two-week summer workshop for high school chemistry and physics teachers in Illinois, built and played with cell-phone spectrometers during the 2009 and 2010 sessions. Those teachers now bring their experience — and assembly instructions — to their classrooms.

Scheeline wrote a detailed account of the cell-phone spectrometer and its potential for chemistry education in an article published in the journal Applied Spectroscopy. He hopes that the free availability of the educational modules and software source code will inspire programmers to develop smart-phone applications so that the analyses can be performed in-phone, eliminating the need to transfer photo files to a computer and turning cell phones into invaluable classroom tools.

“The potential is here to make analytical chemistry a subject for the masses rather than something that is only done by specialists,” Scheeline said. “There’s no doubt that getting the cost of equipment down to the point where more people can afford them in the education system is a boon for everybody.”

Sourced & published by Henry Sapiecha

Killer Disease Decimates

UK Frog Populations

Science (Oct. 8, 2010) — Common frog (Rana temporaria) populations across the UK are suffering dramatic population crashes due to infection from the emerging disease Ranavirus, reveals research published in the Zoological Society of London’s (ZSL) journal Animal Conservation.

Using data collected from the public by the Frog Mortality Project and Froglife, scientists from ZSL found that, on average, infected frog populations experienced an 81 per cent decline in adult frogs over a 12 year period.

“Our findings show that Ranavirus not only causes one-off mass-mortality events, but is also responsible for long-term population declines. We need to understand more about this virus if we are to minimise the serious threat that it poses to our native amphibians,” says Dr Amber Teacher, lead author from ZSL.

Despite a number of populations suffering from infection year-on-year, other populations bounced-back from mass-mortality events. This suggests that some frogs may have some form of immunity to ranaviral infection.

“The discovery of persistent populations in the face of disease emergence is very encouraging and offers hope for the long-term future of this species” says Lucy Benyon, Froglife. “However, we still need regular information from the public on what is happening in their ponds to continue this essential research.”

In the 80s and 90s, the disease was particularly associated with the southeast of England. In recent years new ‘pockets’ of diseases have turned up in Lancashire, Yorkshire and along the south coast.

“It is very difficult to treat wildlife diseases and so the mystery that we desperately need to solve is how the disease spreads. Understanding more about the ecology of the disease will allow us to offer advice to the public on how to limit the spread of infection, which could also prevent the movement of other frog diseases in the future,” says co-author Dr Trent Garner from ZSL.

Sourced & published by Henry Sapiecha