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Why do Zebras have Stripes?

posted Dec 9, 2016, 2:48 PM by Ann Marostica

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There are many theories on why zebras have stripes. Some think the stripes act as camouflage or a way to confuse predators. Others believe the stripes help zebras regulate body heat or choose their mates.

Scientists at the University of California at Davis decided to find the answer. They studied where the species (and subspecies) of zebras, horses, and asses lived. They gathered information on the color, location, and size of stripes on the bodies of the zebras. Then they mapped the locations of tsetse flies and tabanids like horseflies and deer flies. A few other variables, some statistical analysis, and voila. They had their answer.

“I was amazed by our results,” said researcher Tim Caro. “Again and again, there was greater striping on areas of the body in those parts of the world where there was more annoyance from biting flies.”

Zebras are more vulnerable to biting flies because their hair is shorter than that of similar animals like horses. These blood-sucking flies can carry deadly diseases, so it’s important for zebras to avoid this risk.

Other researchers from the University of Sweden found that flies avoid zebra stripes because they’re the right width. If they were wider, the zebras wouldn’t be protected. In that study, more flies were attracted by black surfaces, fewer by white surfaces and the fewest by stripes.

Why is the sky blue?

posted Sep 9, 2016, 3:35 PM by Ann Marostica


Sunlight reaches Earth's atmosphere and is scattered in all directions by all the gases and particles in the air. Blue light is scattered in all directions by the tiny molecules of air in Earth's atmosphere. Blue is scattered more than other colors because it travels as shorter, smaller waves. This is why we see a blue sky most of the time.
Closer to the horizon, the sky fades to a lighter blue or white. The sunlight reaching us from low in the sky has passed through even more air than the sunlight reaching us from overhead. As the sunlight has passed through all this air, the air molecules have scattered and rescattered the blue light many times in many directions.

What makes a red sunset?

As the sun gets lower in the sky, its light is passing through more of the atmosphere to reach you. Even more of the blue light is scattered, allowing the reds and yellows to pass straight through to your eyes.

How can cacti live without water?

posted Aug 26, 2016, 4:08 PM by Ann Marostica   [ updated Sep 9, 2016, 3:02 PM ]

Image result for cactiMost plants lose a large amount of their water through their leaves. Cacti don't have leaves. They have a low surface area which means very little of the plant is exposed to the air. Plus, the skin of the cactus is really thick which helps keep the water from evaporating out through transpiration. 

My dog has fleas...

posted Aug 20, 2015, 9:59 AM by Ann Marostica   [ updated Aug 20, 2015, 10:00 AM ]

Fleas can jump 130 times higher than their own height. In human terms this is equal to a 6ft. person jumping 780 ft. into the air.

Children who avoided peanuts for the first five years of their lives were up to seven times more likely to wind up with peanut allergy

posted Mar 1, 2015, 12:49 PM by Ann Ransom

LA TIMES

It seemed like a good idea at the time: With the incidence of peanut allergy climbing among children, the American Academy of Pediatrics advised parents in 2000 to keep peanuts far away from infants and toddlers who might have a life-threatening reaction to them.

But a new study suggests that advice did more harm than good.

A long-awaited clinical trial has found that small children who avoided peanuts for the first five years of their lives were up to seven times more likely to wind up with a peanut allergy than kids who ate peanuts at least three times a week.

The findings were presented Monday at the annual meeting of the American Academy of Allergy, Asthma and Immunology and published online by the New England Journal of Medicine.

Study: Early exposure may thwart peanut allergy

“The results have the potential to transform how we approach food allergy prevention,” Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said in a statement. The institute helped fund the study.

The trial results offer fresh support for the so-called hygiene hypothesis, which ties the rise in allergies and autoimmune disorders to the ultra-sterile environment made possible by antibacterial soap, disinfectants and other cleansers that have become staples of modern life.

Indeed, a study published Monday in the journal Pediatrics found that children whose families used dishwashing machines were more likely to have allergies than kids whose plates were washed by hand.

All of this unnatural cleanliness robs the immune system of the opportunity to develop resistance to germs and other substances that humans used to encounter on a regular basis.

The result is less immune tolerance — and more allergies. About 3% of children in developed countries are now allergic to peanuts, the study authors say. The rate in the U.S. has tripled over less than two decades, according to figures from the U.S. Centers for Disease Control and Prevention.

Although allergies to eggs and cows’ milk are more common, peanut allergies are the most likely to be life-threatening and generally persist for a lifetime.

The alarming rise of peanut allergies has led to the banning of peanuts from schools, airlines and other venues.

Anecdotal evidence for the hygiene hypothesis came from a 2008 study of Jewish children. Some lived in Britain, where toddlers don’t eat peanuts until they are at least a year old. The others lived in Israel, where infants start eating foods made with peanuts when they are 7 months old.

Although both groups of children had a “similar genetic background,” the British children were 10 times more likely to have peanut allergies than their counterparts in Israel.

Some of the doctors and allergy experts who worked on that study set out to test the hygiene hypothesis.

How secular family values stack up

They enrolled 640 infants in the Learning Early about Peanut Allergy trial — nicknamed LEAP. All the infants were deemed to be at risk of developing peanut allergies because they were already allergic to eggs or had severe eczema, a skin condition that can be caused by allergies.

All the infants were between 4 and 11 months old when they joined the study.

Researchers conducted a skin-prick test to see whether the infants had any sensitivity to peanuts at the start of the study. Then they were randomly assigned to either consume at least 6 grams of peanut protein per week — in the form of a smooth peanut butter or a peanut snack called Bamba — or to avoid peanuts altogether.

Children who showed some peanut sensitivity and were sorted into the peanut-eating group had to pass a peanut food challenge to make sure they could handle their assignment. Six who had a reaction to peanuts were reassigned to the peanut-avoidance group.

The researchers examined the children in two groups — the 85% who had no sensitivity to peanuts at the start of the study and the 15% who were already developing peanut allergies.

In both groups, the results were striking.

Among the children with no sign of peanut allergy at the start of the trial, 13.7% of those who avoided peanuts became allergic by the time they turned 5.

But among the children who ate peanuts regularly, only 1.9% became allergic. That amounted to an 86% relative reduction in peanut allergy risk, the study authors found.

Peanut exposure was also helpful for kids who were already on the road to peanut allergies. Among the 5-year-olds, the allergy rate for those who avoided peanuts was 35.3%, compared with only 10.6% for those who ate peanuts. That worked out to a 70% relative reduction in allergy risk, according to the study.

Kids' food allergies cost U.S. nearly $25 billion a year, study finds

The researchers were able to collect dust samples from the beds of nearly two-thirds of the children at the end of the trial. Children who ate peanuts had a median of 91.1 micrograms of peanut particles in their bed dust, while their peanut-avoiding counterparts had a median of only 4.1 micrograms of peanut.

In addition, blood tests showed that the children who ate peanuts had higher levels of two types of peanut-related antibodies than the children who avoided the nuts.

Peanut exposure had its problems. Five types of side effects — upper respiratory tract infections, viral skin infections, hives, gastroenteritis and conjunctivitis — occurred more frequently among the peanut eaters than the peanut avoiders.

But the severity of these side effects tended to be mild or moderate, according to the study.

“This intervention was safe, tolerated, and highly efficacious,” the study authors wrote.

The American Academy of Pediatrics has already withdrawn its endorsement of peanut avoidance. And in the years after the study of Jewish children was published, researchers reported similar findings about allergies to eggs and cow’s milk.

Many questions remain, however. Among them: How much peanut protein do children need to eat to reduce their allergy risk? Will the protective effect wear off if kids stop eating peanuts?

The researchers plan to find out by tracking the study participants through a study they have dubbed LEAP-On.

In the meantime, two pediatric allergy specialists suggest that infants at risk for peanut allergy should try a similar regimen of peanut exposure.

“The results of this trial are so compelling, and the problem of the increasing prevalence of peanut allergy so alarming, new guidelines should be forthcoming very soon,” they wrote in an editorial that accompanies the study in the New England Journal of Medicine. “The LEAP study makes it clear that we can do something now to reverse the increasing prevalence of peanut allergy.”

karen.kaplan@latimes.com

The Blood Vessels of the Human Body

posted Mar 1, 2015, 12:44 PM by Ann Ransom   [ updated Mar 1, 2015, 12:46 PM ]

Sea Slug Steals Photosynthesis Genes From Algae

posted Feb 8, 2015, 7:59 PM by Ann Ransom

The brilliant emerald green sea slug, Elysia chlorotica, spends months living on sunlight just like plants. It’s been called the photosynthesizing sea slug in the past, but how it manages to do this as well as it does is a complete mystery. In a new study appearing in theBiological Bulletin, researchers reveal that the sea slug has incorporated genes from the algae that it eats. 

"There is no way on earth that genes from an alga should work inside an animal cell," saysSidney Pierce from the University of South Florida. "And yet here, they do. They allow the animal to rely on sunshine for its nutrition. So if something happens to their food source, they have a way of not starving to death until they find more algae to eat."

Chloroplast are plant organelles that contain chlorophyll, the green photosynthetic pigment. Researchers have known since the 1970s that this sea slug steals chloroplasts from the alga Vaucheria litorea. The sea slugs embed the chloroplasts into their own digestive cells, where the organelles continue to photosynthesize for up to nine months—that’s even longer than they would perform in algae. The sea slugs stay nourished thanks to the carbohydrates and lipids produced with photosynthesis. 

But until now, no one knew for sure how the slugs manage to maintain these pilfered chloroplasts. Using DNA amplification, sequencing, and advanced imaging techniques, Pierce and colleagues revealed that the sea slug’s chromosomes contain genes from the algae that code for both chloroplast proteins and chlorophyll synthesis.

"This paper confirms that one of several algal genes needed to repair damage to chloroplasts, and keep them functioning, is present on the slug chromosome," Pierce explains in a news release. "The gene is incorporated into the slug chromosome and transmitted to the next generation of slugs." And even though future slugs will need to snatch up new chloroplasts from algae, the genes to maintain them are already in the slug genome. 

These sea slugs are one of the only known examples of functional gene transfer from one multicellular species to another. "When a successful transfer of genes between species occurs, evolution can basically happen from one generation to the next," Pierce adds, rather than over thousands of years.

you should add these to your holiday lists!!

posted Nov 30, 2014, 9:30 PM by Ann Ransom

Photo: Awesome science-themed Christmas gift ideas for kids.  Astronaut bed cover: amzn.to/1y4WiH6 Periodic blocks: amzn.to/1vYEui2 Microscope: amzn.to/1vxYeGX Human body kit: amzn.to/11FyRqW Moon night-light: amzn.to/1yq7ME0 Dinosaur excavation kit: amzn.to/1w6VhPi Big bag of science: amzn.to/1uZD8MEAstronaut bed cover: amzn.to/1y4WiH6
Periodic blocks: amzn.to/1vYEui2
Microscope: amzn.to/1vxYeGX
Human body kit: amzn.to/11FyRqW
Moon night-light: amzn.to/1yq7ME0
Dinosaur excavation kit: amzn.to/1w6VhPi
Big bag of science: amzn.to/1uZD8ME

Exercise promotes brain activity

posted Nov 2, 2014, 8:35 PM by Ann Ransom

Move around!

Exercise helps promote brain activity, releasing endorphins and the protein BDNF (Brain-Derived Neurotrophic Factor), which help clear your mind of stresses and help you feel better.
Read more: http://bit.ly/1szzQ1z

Photo: Move around!   Exercise helps promote brain activity, releasing endorphins and the protein BDNF (Brain-Derived Neurotrophic Factor), which help clear your mind of stresses and help you feel better.   Read more: http://bit.ly/1szzQ1z  [Fast Company]

Does my voice really sound like that?

posted Oct 12, 2014, 9:03 PM by Ann Marostica

Sorry, your voice actually DOES sound like that in real life. This is why.

Why does your voice sound so different in recordings?



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