Science & TechnologyS


Megaphone

Coke cans focus sound waves

Richard Chirgwin
The Register
Wed, 13 Jul 2011 01:23 UTC
Pepsi scrambles taste-test response

Focused sound waves aren't just the domain of children fooling around with long-distance microphones. They're also important in ultrasound machines, and in biomedical laboratories, for "acoustic actuators" using sound to sort cells.

Sound focusing has its limits, however - the diffraction limit, roughly one wavelength of the sound being focused. A 20 KHz tone has a wavelength of around 1.7cm in air, which is one of the reasons that ultrasound pictures look fuzzy and indistinct to the untrained eye. To improve the focus beyond the diffraction limit, you need expensive acoustic lenses - or an array of Coca-Cola cans.

In an experiment reported at Nature News, a French researcher has built a "superlens" out of a 7x7 array of soft drink cans with the tabs removed.
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Fish

Jellyfish Swim for Their Supper

Wynne Parry
Live Science
Tue, 12 Jul 2011 20:01 UTC
Jellyfish_1
© Gower Coast AdventuresTags that recorded depth and time attached to jellyfish off the Welsh coast revealed the animals actively swim up and down, rather than drifting.

Jellyfish actively swim high and low to catch food, rather than drift passively, according to a study of large barrel jellyfish off the Welsh coast. This behavior may explain some of gelatinous blobs' success.

"It is just another feature of jellyfish that is going to help them outcompete fish and take over from fish in disturbed ecosystems," said lead researcher Graeme Hays, a professor at Swansea University in Wales.

Since jellyfish and young fish both eat plankton (tiny floating plants and animals), jellyfish can quickly gain an advantage when some other disruption - such as overfishing, or a low-oxygen environment created by nutrient pollution - hurts fish populations.

In fact, in recent years, reports of swarms of jellyfish have suggested human-caused changes to ocean environments may be just what these creatures need to thrive.
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Info

Dinosaurs Became Extinct in Single Blow, Fossil Suggests

Charles Q. Choi
Live Science
Tue, 12 Jul 2011 20:01 UTC
Killer Rock
© NASA/JPLA meteor strike 65 million years ago likely wiped out the dinosaurs, with a new study suggesting the demise was a quick one.
A dinosaur horn is now pointing to a catastrophic end for the Age of Dinosaurs, not a gradual one as some researchers have claimed.

The leading culprit for the end of the Age of Dinosaurs is a catastrophic meteor strike about 65 million years ago. Although it is now widely accepted that a cosmic impact took place about then - a time known as the Cretaceous-Tertiary, or K-T boundary - it was unclear if the mass extinctions started gradually before the hit, perhaps due to volcanoes or other factors.

Helping drive this controversy was a zone spanning 10 feet (3 meters) wide in the earth right below the K-T boundary that purportedly lacked dinosaur fossils. A number of scientists have claimed this gap, seen in the western interior of North America, was evidence that dinosaurs might have died off well before any impact. Other researchers have contested the notion, suggesting this layer only appeared devoid of fossils because fossils can get easily destroyed over millions of years. Also, the placement of the K-T boundary can be uncertain, meaning that dinosaurs might have actually been found in this zone before but not reported as such.
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Info

Blood Type Linked to Earlier Decline in Fertility

Luke Yoquinto
MyHealthNewsDaily
Tue, 12 Jul 2011 09:36 UTC
Blood Test
© Live Science

A woman's blood type may yield clues to her fertility, a new study suggests.

The results show that, of a group of women in their 30s who sought medical fertility help, those with blood type O were more likely than women with other blood types to have diminished ovarian reserve, meaning their ovaries had few eggs or had eggs unlikely to meet with success during in vitro fertilization procedures. Type O blood is the most common type in the United States.

"I don't want the message to be that women in the healthy population should be petrified that their blood type may predict compromised fertility," said study author Lubna Pal, who researches reproductive endocrinology at the Yale University School of Medicine.

But if the study's link is shown to hold up for other women, then the connection may provide a tool for earlier, more accurate fertility prognoses, Pal said.

The study was published online on June 26 in the journal Human Reproduction.
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Magnet

Magnetism Prevents Memory Loss?

Marieke Vos-Zweers
The Epoch Times
Mon, 11 Jul 2011 16:18 UTC
Magnetism Brain
© Photos.comTranscranial magnetic stimulation creates a magnetic field that can stimulate a current to flow in the brain.
Learning new skills or facts in quick succession could become less challenging with the help of magnetism, according to new research by American neurologists.

Dr. Edwin Robertson and Dr. Daniel Cohen from the Harvard Medical School's Beth Israel Deaconess Medical Center in Boston investigated whether it is possible to prevent interference between memory tasks.

"For the last 100 years, it has been appreciated that trying to learn facts and skills in quick succession can be a frustrating exercise," said Robertson in a press release.

"Because no sooner has a new memory been acquired than its retention is jeopardized by learning another fact or skill."

Robertson and Cohen recruited 88 students to learn a simple motor skill task and then a word list rapidly after. The following day, the students were tested and had already forgotten some of their new skills.
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Info

New Dino Finding: Warm-Blooded, Nimble Beasts

Remy Melina
Live Science
Tue, 12 Jul 2011 13:24 UTC
Dino Bones
© Donald Henderson| Royal Tyrrell Museum in Alberta, CanadaResearchers studied tiny holes in dinosaur bones, including the femur of Centrosaurus apertus, a ceratopsian dinosaur.
Rather than plodding along Earth like slowpokes, dinosaurs likely were pretty active beasts, even more so than today's mammals, researchers have now found.

The finding, which was based on tiny holes that would've supplied blood and oxygen to dinosaur bones, supports the idea that at least some dinosaurs may have been warm-blooded, the researchers say.

"One of the big controversies among paleobiologists is whether dinosaurs were cold-blooded and sluggish or warm-blooded and active," study researcher Roger Seymour of the University of Adelaide said in a statement.

To find out, researchers began measuring nutrient foramen, or the tiny holes located in thigh bones. The holes supply blood to the living bone cells inside, with past research suggesting the size of the holes in human bones is related to the maximum rate that a person can be active during aerobic exercise.
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Question

Out-of-body hallucinations linked to brain glitch

Jennifer Welsh
Live Science
Tue, 12 Jul 2011 13:09 UTC
OBE Experience
© Mangojuicy | Dreamstime.comAbout 10 percent of the general population has had an out-of-body experience at some point in their lives.
Out-of-body hallucinations can be freaky, and are often associated with mental or physical illness. New research has linked these experiences to instabilities in a part of the brain called the temporal lobe, and to errors in the body's sense of itself - even in healthy individuals.

"Seems to be that all of us can be placed somewhere along a sliding scale, based on how unstable or erratic our temporal lobe is, and some people are more prone to these experiences," said study researcher Jason Braithwaite of the University of Birmingham.

The temporal lobe interprets the sensory and other information coming in from the body and places it on a body map, giving us our sense of being inside our body, of looking out from our eyes. If this interpretation goes wrong, a hallucination can occur in which a person sees themselves from outside of their body, also called an out-of-body experience (OBE).
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Magic Wand

How tough turtles survived catastrophic meteor: Cretaceous animals adapted in mass extinction that wiped out dinosaurs

Jennifer Welsh
Live Science
Mon, 11 Jul 2011 08:46 UTC
Image
© Brian T. Roach, Yale Peabody MuseumReconstruction of the baenid turtle Boremys basking on a Triceratops dinosaur skull. Boremys were one of several turtle species that survived the asteroid impact that killed the dinosaurs (other than birds) at the end of the Cretaceous Period.
What does it take to survive a catastrophic meteor impact? The tough turtles of the Cretaceous know a bit about that; they seem to have survived the mass extinction that wiped out the dinosaurs because of their slow metabolisms and aquatic lifestyles, researchers now say.

"Turtles are very tough animals, if times get tough they can go into a state of animation," said study researcher Tyler Lyson, of Yale University. "Animals that were living in the water were kind of protected against whatever killed the land plants and the dinosaurs."

Essentially, since their bodily processes were so slow, needing very little energy, they could survive on sparse resources during and after the wipeout of dinosaurs.
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Telescope

Today is the first anniversary of the discovery of Neptune - in Neptune years

Charlie Jane Anders
io9
Mon, 11 Jul 2011 01:30 UTC
Image
© NASA
July 11, 2011 marks the first full orbit of the planet Neptune since its discovery on the night of September 23-24, 1846. The discovery of Neptune is a fascinating story, full of near misses and the triumph of math.

For many years we've been taught that the discovery of Neptune was done by mathematical calculations. This came about in 1821 when Alexis Bouvard was publishing his findings for Uranus and noticed a gravitational perturbation in Uranus' orbit. This led him to hypothesize an unknown body was crossing the path. Enter miscommunications, politics and astronomer John Adams...

"It is more likely that Adams realised that his proposed orbits were moving ever closer to a "forbidden" zone of resonance." says Brian Sheen of Roseland Observatory. "Uranus orbits in 84 years, Neptune in 165, nearly a 2:1 resonance, this brings about much greater perturbations than were being measured. In fact the mid 19th century is a quiet period and much bigger swings are evident now."

In 1843 John Couch Adams used the data Bouvard proposed to begin working on a proposed orbit, but it would be several years later before Urbain Le Verrier verified its existence through physical observation - at the same time as Johann Gottfried Galle. Says Sheen; "It is often said that Adams never published his results. In fact a published paper was printed by November 1846 and appeared in the 1851 Nautical Almanack published in 1847."
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Fish

Before animals first walked on land, fish carried gene program for limbs


University of Chicago Medical Center
Mon, 11 Jul 2011 22:03 UTC
Image
© Igor Schneider/University of ChicagoA genetic switch taken from the skate activates a marker gene in the distal limb of the mouse embryo.
Genetic instructions for developing limbs and digits were present in primitive fish millions of years before their descendants first crawled on to land, researchers have discovered.

Genetic switches control the timing and location of gene activity. When a particular switch taken from fish DNA is placed into mouse embryos, the segment can activate genes in the developing limb region of embryos, University of Chicago researchers report in Proceedings of the National Academy of Sciences. The successful swap suggests that the recipe for limb development is conserved in species separated by 400 million years of evolution.

"The genetic switches that drive the expression of genes in the digits of mice are not only present in fish, but the fish sequence can actually activate the expression in mice," said Igor Schneider, PhD, postdoctoral researcher in the Department of Organismal Biology and Anatomy at the University of Chicago and lead author on the paper. "This tells us how the antecedents of the limb go back in time at every level, from fossils to genes."
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