Biology Projects from 2CO

Great work from 2CO! Very impressive!

1. Sensations by Miriam, Weixin, Ellis and Grace

2. DNA by Yanxuan, Kayean, Hannah, Charisse and Yingying

3. Prime Investigators by Su Jin, Kaysee, Samantha and Yun Rui

4. Ace Attorney game by Kimberly Quah, Kirsten, Megan, Amanda and Xinhui

5. Aging by Chloe, Jaime, Hillary and Clare

Physics to Excite!

Hi 1SE, here are your photos for Physics to excite. Most photos were badly taken because there were students who refused to look at the camera or blocked themselves from view >=( Anyway, looks you had a great time and learnt a lot!

Food Entrepreneurs

Hi girls you can access your photos here. Glad to see that everyone had fun! XD

Photos to Underwater World Sleepover Program are here!! Photos will be uploaded in batches though, because they came from different cameras so I will need some time collating them. Check again at the end of the week, especially for the sea lion photos.

Common weed-killer chemically castrates frogs: study

WASHINGTON (AFP) - – One of the most common weed-killers in the world, atrazine, causes chemical castration in frogs and could be killing off amphibian populations worldwide, a study published showed.

Researchers compared 40 male control frogs with 40 male frogs reared from the moment they hatched from eggs until full sexual maturity in atrazine concentrations in the range that animals experience year-round in areas where the chemical herbicide is found.

Ninety percent of the male frogs exposed to atrazine had low testosterone levels, decreased breeding gland size, feminized laryngeal development, suppressed mating behavior, reduced sperm production and decreased fertility, while the control group showed features typically found in male frogs.

And what happened to the remaining 10 percent of atrazine-exposed frogs was deemed "the most dramatic finding" of the study by the researchers, led by Tyrone Hayes of the University of California at Berkeley: they developed into females that copulated with males and produced eggs.

The larvae from those eggs were all male, the study published in the Proceedings of the National Academy of Sciences (PNAS) found.

"Many studies have focused on death from disease and its role in global amphibian declines and sudden disappearances of populations, but virtually no attention has been paid to the slow, gradual loss of amphibian populations due to failed recruitment," the study said.

"The production of sex-reversed all male-producing animals could drive populations to extinction," the authors of the study warned.

Earlier studies have found that atrazine also caused feminization in zebra fish and leopard frogs and caused a significant decline in sperm production in male salmon and caiman lizards.

Atrazine is widely used by farmers in 60 countries around the world as a weed- and grass-killer, particularly in fields of corn, grain sorghum and sugar cane. It is also used on golf courses.

Apart from the United States, Australia and China are among the biggest markets for atrazine, according to Tim Pastoor, principal scientist for Syngenta, the US company that makes the herbicide.

Atrazine is banned in the European Union, but farmers there use an almost identical chemical called terbuthylazine, Pastoor said.

Environmental activist organizations in the United States have called for atrazine to be taken off the market in the United States, but the Environmental Protection Agency (EPA) four years ago refused to ban the chemical.

"The EPA have already considered the question of whether or not atrazine will affect frogs' sexual development, and the answer to that is clearly no," Pastoor told AFP.

"But the main reason Syngenta stands behind atrazine is because farmers have come to us and said, 'Please keep this product on the market.'

"The reason they ask us is because it's a product that works, it increases crop yields, and it's inexpensive, and something that's inexpensive and works is magic to a farmer," said Pastoor.

Around 80 million pounds of atrazine are applied annually to crop fields in the United States alone, and half a million pounds of the herbicide fall to earth in rainfall in the United States, some of it hundreds of miles from the farmland where it was originally applied, the study says.

"Atrazine can be transported more than 1,000 kilometers (620 miles) from the point of application via rainfall and, as a result, contaminates otherwise pristine habitats," the study says.

Atrazine has also been associated with low sperm count, poor semen quality and prostate problems in humans.

A small study led in 2003 by University of Rochester professor in environmental medicine Shanna Swan found that men who lived in the Midwest -- the biggest corn-growing region in the United States -- who had high levels of atrazine in their urine also had low sperm counts.

"We haven't been able to follow up and confirm that study, but it did find an association," Swan told AFP.

"But the important message here is: this is a very prevalent exposure. Human beings are definitely exposed, and a lot of them, because it's the most commonly used pesticide," Swan said.

Reference: Yahoo Singapore News

Third-hand smoke also bad for you: study

WASHINGTON (AFP) - – You know smoking is bad for you. You know inhaling someone else's smoke is bad for you. Now a US study says third-hand smoke -- tobacco residue clinging to surfaces -- is also bad for you.

When a cigarette burns, nicotine is released in the form of a vapor that collects and condenses on indoor surfaces such as walls, carpeting, drapes and furniture, where it can linger for months, said the study, which was published in the Proceedings of the National Academy of Sciences (PNAS).

"Our study shows that when this residual nicotine reacts with ambient nitrous acid it forms carcinogenic tobacco-specific nitrosamines, or TSNAs," said Hugo Destaillats, a corresponding author of the study.

"TSNAs are among the most broadly acting and potent carcinogens present in unburned tobacco and tobacco smoke," he said.

The most likely human exposure to TSNAs is through either inhalation of dust or the contact of skin with carpet or clothes -- making third-hand smoke particularly dangerous to infants and toddlers.

Opening a window or turning on a fan to air out a room while a cigarette burns does not eliminate the hazard of third-hand smoke. Smoking outdoors doesn't help much either.

"Smoking outside is better than smoking indoors but nicotine residues will stick to a smoker's skin and clothing," said Lara Gundel, a co-author of the study.

"Those residues follow a smoker back inside and get spread everywhere. The biggest risk is to young children," she said.

"Dermal uptake of the nicotine through a child's skin is likely to occur when the smoker returns and if nitrous acid is in the air, which it usually is, then TSNAs will be formed."

Substantial levels of TSNAs were also found in the truck of a heavy smoker, the study says, adding that most vehicle engines emit some nitrous acid that can infiltrate the passenger compartment of a vehicle.

Researchers from the Lawrence Berkeley National Laboratory led the study, which they say is the first to quantify the reactions of third-hand smoke with nitrous acid.

Reference: Yahoo news: Third hand smoke also bad for you

Imagination

"Imagination is everything. Imagination is more important than knowledge. For knowledge is limited to all we now know and understand, while imagination embraces the entire world, and all there ever will be to know and understand." Albert Einstein

I have been thinking about this quote by Einstein. Science and maths have always been subjects that required a lot of imagination without us realising it. In maths, numbers require imagination because they are abstract in nature. For example, there is no such thing as a "5". It cannot be seen. However, you can see 5 oranges, 5 cars and 5 tables. "5" therefore, is something that we have to imagine and relate to in order to grasp the fundamentals of maths, such as addition and subtraction.

Likewise, there is a lot of imagination in biology. We cannot see molecules or atoms floating about within our body. Yet, they are there and we have to imagine how these small particles come together to make up the whole organism. Sometimes, imagination is hard work, but with time, imagination lays the foundation for greater discoveries.

Please don't lose your imagination and ability to visualize and understand the "scientific definitions"! On a lighter note, here is a really imaginative movie :) :