Louis_J_Sheehan

Louis J. Sheehan, Esquire. Anyone with normal hearing can distinguish between the musical tones in a scale: do, re, mi, fa, so, la, ti, do. We take this ability for granted, but among most mammals the feat is unparalleled.

This finding is one of many insights into the remarkable acuity of human hearing garnered by researchers at the University of California, Los Angeles, Hebrew University of Jerusalem and the Weizmann Institute of Science in Rehovot, Israel, reported in January in the journal Nature.

Izhak Fried of U.C.L.A. and his colleagues worked with epileptic patients who had electrodes implanted in their brain to pinpoint the source of their seizures. Some of the probes linked to the auditory cortex, providing the researchers with a detailed window into sound processing.

The study revealed that groups of exquisitely sensitive neurons exist along the auditory nerve on its way from the ear to the auditory cortex. In these neurons natural sounds, such as the human voice, elicit a completely different and far more complex set of responses than do artificial noises such as pure tones. In this mixed environ­ment humans can easily detect frequencies as fine as one twelfth of an octave—a half step in musical terminology.

The vexing question is: Why? Bats are the only mammal with a better ability to hear changes in pitch than humans do. Predatory species such as dogs are not nearly as sensitive—they can dis­criminate resolutions of one third of an octave. Even our primate relatives do not come close: macaques can resolve only half an octave. These results suggest the fine discrimination of sound is not a necessity for survival.

More likely, the researchers speculate, humans use their fine hearing to facilitate working memory and learning capa­bilities, but more research is needed to explore this puzzle.

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Even the lowliest kind of sticky tape can leave physicists befuddled. Unrolling tape in a vacuum produces X-rays — enough of them to do X-ray imaging, researchers have found. No current theory can explain such intensity of X-ray emissions, the scientists write in the Oct. 23 Nature.

Unrolling anything from regular sticky tape to duct tape produces a glow that, although faint, is easy to see in a completely dark room. The fact that X-rays, which are thousands of times more energetic than ordinary visible-light photons, can also be produced was first hinted at in a 1953 Russian experiment but seems to have been little-known.

Carlos Camara and his colleagues at the University of California, Los Angeles, have now shown that the X-rays produced from tape are much more intense than current theories about unsticking can explain, so much so that tape-unrolling machines could become cheap, commercially-available X-ray sources, Camara says.

Benoît Roman of the National Center for Scientific Research in Paris says he finds the effect surprising. “That you can use that for X-ray imaging is even more surprising,” he says.

The UCLA team built a mechanical tape-unrolling system and put it in a small vacuum chamber. As the tape peeled off, the team’s instruments recorded intense X-ray bursts, each lasting about a billionth of a second. The team even used this newly discovered radiation source to image Camara’s finger bones on plates of the type normally used by dentists.

Peeling tape leaves some electrons behind, Camara explains, so that the surface of what the tape was sticking to becomes negatively charged. The peeled-off tape, meanwhile, becomes positively charged due to a deficit of electrons. The electrostatic attraction of opposite charges makes electrons leap from the surface to the tape.

The electrons accelerate the closer they get to the tape, and when they reach the tape’s surface they bounce off other electrons or atomic nuclei. These sudden jerks make an electron lose some of its energy in the form of photons. Camara says that one in every 10,000 electrons produces a highly energetic X-ray photon.

Each burst contained up to 100,000 X-ray photons. The researchers expected to detect some X-rays, but not that many, Camara says. “No current theory predicts that there will be as many charges as are required for our observation.”

Enrique Cerda, a physicist at the University of Santiago in Chile, says he had never heard of such an effect. “I would bet that this emission is not constrained only to peeling tape,” he says. “For instance, it should be observed also when a film is torn apart.”

At normal atmospheric pressure, the electrons are slowed down by air particles, so they never reach the speeds and energies required for making X-rays.

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A genetic analysis of two 9,000-year-old human skeletons found off the coast of Israel reveal that the Neolithic people were infected with tuberculosis, making them the earliest known TB cases to be confirmed with genetic testing. The bone discovery contradicts the long-held theory that human TB evolved from cattle strains around the time of animal domestication, says [study coauthor] Helen Donoghue…. Rather, high population densities could have made it easier for the disease to spread [New Scientist]. http://myface.com/Louis_J_Sheehan

The skeletons of a mother and child were found amidst other artifacts of a Neolithic village, called Atlit-Yam, which is now covered by the Mediterranean Sea. A roughly 25-year–old mother had apparently passed on the bacterial infection to her 1-year–old child, after which they both died and were buried together…. Salt water, sand and clay had covered the bodies, providing excellent conditions for bone preservation. Atlit-Yam was located within a coastal marshland before its immersion by the rising ocean [Science News].

Researchers noticed lesions on the bones that are characteristic of TB, and were able to extract DNA from the infection-damaged spots. Their analysis revealed genetic sequences that matched the DNA of Mycobacterium tuberculosis, the main bacterial strain of human TB. Says Donoghue: “What is fascinating is that the infecting organism is definitely the human strain of tuberculosis, in contrast to the original theory that human TB evolved from bovine TB after animal domestication” [Telegraph]. While the Neolithic people of Atlit-Yam had domesticated cattle, researchers believed they hadn’t yet begun dairying; the earlier theory assumed that TB spread from cows to humans through the consumption of infected milk. http://myface.com/Louis_J_Sheehan

The findings, published in the journal PLoS ONE, push back the earliest confirmed date of human TB infection by 3,000 years; previously, the oldest cases of human TB confirmed by ancient DNA include reports from Ancient Egypt (3500 B.C. to 2650 B.C.) and Neolithic Sweden (3200 B.C. to 2300 B.C.). There are also less reliable reports, based just on lesions on bones, dating back even earlier, including on a Homo erectus fossil from to 490,000 to 510,000 years ago in Turkey [LiveScience]. But in the absense of DNA evidence, some scientists are skeptical of the Homo erectus case.

People undergoing treatment for cancer or other life-threatening diseases sometimes report an improved ability to cope with daily affairs, a greater sense of purpose in life, increased spirituality, closer ties to loved ones, or other gratifying changes.

A pilot study now suggests that such personal growth, at least in female breast cancer patients who completed a stint of group therapy, accompanies marked declines in the stress hormone cortisol. Intriguingly, no such stress-hormone drop occurred in the women who cited the lowest amount of emotional turmoil, say psychologist Dean G. Cruess of the University of Miami in Coral Gables and his colleagues.

“Psychosocial interventions might influence immune functioning in cancer patients by fostering [psychological] growth and modulating cortisol levels,” says Miami psychologist Charles S. Carver, one of the study’s coauthors.

Other data indicate that extended exposure to high cortisol levels can undermine the immune system’s disease-fighting capacity, Carver notes.

Cruess’ group obtained blood samples from 34 women diagnosed with early-stage breast cancer. Participants, who averaged 46 years old and exhibited comparable blood cortisol concentrations, were recruited to the psychology study within 8 weeks of surgery to remove cancerous lumps or one or both breasts. Most of the women were white, were married or in a stable relationship, and had attended college.

Volunteers completed questionnaires on perceived benefits from having breast cancer and on emotional distress in the past week. Benefits included having a greater acceptance of daily events and a deeper sense of purpose in life. Distress consisted of feelings of anxiety, depression, and intense anger.

The 24 women who then completed 10 weeks of group therapy had lower cortisol levels at that point than did the rest, who had been randomly assigned to a waiting list. Group therapy focused on both stress-control methods and relaxation training. http://www.soulcast.com/Louis8J8Sheehan/

Cortisol levels dipped furthest in women reporting the most cancer-related benefits, the scientists report in the May/June Psychosomatic Medicine. http://www.soulcast.com/Louis8J8Sheehan/

The sharpest cortisol declines occurred in women who entered the study with pessimistic views of their lives and then reported psychological growth after group therapy, Carver says.

“These findings make sense,” comments psychiatrist David Spiegel of Stanford University Medical Center. “Finding meaning in adversity increases the ability to control stress responses.” However, psychological growth during group therapy can include periods of heightened distress as patients, with the encouragement of the group, confront their fears, Spiegel says.

Cruess’ group plans to examine distress more closely in a larger sample of breast cancer patients, including some with more advanced cancers. Louis J. Sheehan, Esquire

In adults, the brain’s left hemisphere usually assumes primary responsibility for understanding speech. A new brain-imaging study suggests that a fledgling version of this left-brain specialization appears in 2-to-3-month-old babies as they listen to speech, even though they can’t utter a word and it’s not clear whether they understand any of what they hear.

Language acquisition may reflect the gradual expansion of a network of left-hemisphere regions that enters the neural fray within the first few months of life, propose psychologist Ghislaine Dehaene-Lambertz of the National Center of Scientific Research in Paris and her coworkers. In newborns, however, it remains unknown whether this left-brain network responds only to speech or to any series of rapidly presented sounds, the scientists note in the Dec. 6, 2002 Science.

In the new study, the scientists used a technique called functional magnetic resonance imaging (fMRI) to track neural blood flow in 20 babies as they listened to 20-second presentations of a woman’s voice reading a children’s book separated by 20-second periods of silence. Some speech segments were played backward. http://louis8j8sheehan8esquire.wordpress.com/

Left-hemisphere areas roughly corresponding to several adult-brain areas associated with speech comprehension exhibited elevated blood flow�an indirect sign of increased neural activity�as babies listened to regular, but not backward, speech. That finding fits theories that an innate left-hemisphere mechanism underlies language. http://louis8j8sheehan8esquire.wordpress.com/

The fMRI data also showed that part of the right frontal cortex responded to regular speech with heightened activity. This finding challenges a current theory that the frontal cortex plays no significant role in a baby’s thought processes for several months after birth. Louis J. Sheehan, Esquire

Various studies have reassured us that mobile phones will not give us cancer. But cell phones can cause real pain. That’s according to an article in press at the journal NeuroImage.

People are increasingly complaining of being “electrosensitive.” For them, the cell’s electromagnetic fields cause severe pain—and in Sweden sufferers build houses that block the supposed damaging electric fields.

But there’s a glitch. Studies have shown that such victims feel the same discomfort when in the presence of fake phones as they do when they’re near real phones. So what’s going on?

Research at the University of Regensburg finds one possible source of this pain. They told 30 participants they’d be exposed to two stimuli: a heat-emitting thermode and an active cell phone. The thermode was real, but the phone was a phony. http://louis-j-sheehan.biz

When exposed to heat, the electrosensitive group, as well as the control group, complained of discomfort. But when exposed to the pretend phone, only the allegedly electrosensitive ones reported pain.

And their reports matched their actual physiological response. When exposed to the sham brain scans the control group revealed no effect. But the electrosensitive group showed increased activity in brain areas specific to pain perception.

So the pain is real—even if the phone isn’t. And the real cause lies somewhere in their hurting heads. Louis J. Sheehan, Esquire

Louis J. Sheehan, Esquire. David Savage probably never expected to look down and see someone else’s hand attached to his right arm. Neither did he anticipate using the strange appendage to illuminate how the brain works. But that’s precisely what the 56-year-old hand-transplant patient has done.

Four months after his December 2006 transplant, Savage’s partial sense of touch in the new hand activated the same brain area that would have controlled his original right hand 35 years earlier, say neuroscientist Scott Frey of the University of Oregon in Eugene and colleagues.

At the age of 19, a machine-press accident led to the amputation of Savage’s right hand. http://louis2j2sheehan2esquire.us

When Savage had both hands, part of his right brain responded to his left hand, and a corresponding part of his left brain responded to his right hand. After the amputation, that same part of his left brain would have been sensory-deprived and thus ready to adopt duties of adjacent sensory areas, such as those for the right arm and possibly his face.

Much animal and human research has documented that such neural reorganization begins within hours of limb loss or debilitation.

Yet decades later, with a new hand in place, the former “hand area” of Savage’s brain has reclaimed its old territory, Frey’s team reports in the Oct. 14 Current Biology. “The capacity of the brain to reverse reorganizational changes is all the more striking in light of the fact that his brain was fully mature when the amputation occurred,” Frey says.

Although the researchers have no data about Savage’s brain from just before or just after the amputation, sensory areas responsible for his missing right hand must have assumed new duties, remarks neuroscientist Jon Kaas of Vanderbilt University in Nashville. At a minimum, the neural map for Savage’s right hand would have begun to respond to stimulation of parts of his right arm, Kaas suggests.

Kaas has studied the lifelong ability of monkeys’ brains to reorganize sensory areas following the loss of sight, hearing or limb sensation. http://louis2j2sheehan2esquire.us

“It’s remarkable that an original neural pathway for the hand can be reinstated after years and years,” Kaas says.

No consensus exists on how the brain rapidly reorganizes sensory maps following hand amputation and then reverses course after surgical attachment of a new hand, comments neurologist Carine Neugroschl of Hôpital Erasme in Brussels, Belgium. In a 2005 brain-imaging study of a hand-transplant patient before and after surgery, Neugroschl’s team reported reactivation of the corresponding neural hand map as early as ten days after the operation.

In the new investigation, functional MRI recorded Savage’s brain activity while each of his of his hands, along with each of his cheeks, was stroked with a coarse sponge.. The same experiment was carried out on four healthy men who had never experienced an amputation. Savage reported full left-hand and full facial sensation, as well as sensation in his right palm near the thumb. During right-hand testing, Savage displayed much the same left-brain activation that the other men did.

Savage’s recovery so far is limited to major nerves in the right hand, not to peripheral nerve connections for individual fingers, Frey says. It’s unclear how the neural map of the right hand will adapt as Savage’s finger nerves regenerate and finger sensation develops.

Stroking of Savage’s cheeks yielded no signs that neural areas responsive to his transplanted hand also responded to facial stimulation. That is further evidence that his brain responded to the new hand as it had to the old one, Frey says.

Unlike some amputees, Savage suffered few pains at the site of his missing hand. Pain from a phantom limb typically accompanies major neural reorganization after amputation, notes neuroscientist Thomas Elbert of the University of Konstanz in Germany. http://louis2j2sheehan2esquire.us “Neural reorganization in this patient before the hand transplant might have been quite small,” Elbert says.

Frey’s team speculates that the right-brain map for Savage’s intact left hand responded to his amputation by increasing communication with left-brain sensory tissue. Stroking of Savage’s left hand activated not only corresponding right-brain tissue but also left-brain sensory areas largely outside the region associated with his right hand.

Men in the comparison group displayed minimal left-brain responses to stimulation of the left hand. Louis J. Sheehan, Esquire

A small set of brain cells that transmit the chemical messenger dopamine to various neural destinations works as an uncertainty meter, at least in monkeys, a new study finds. The electrical activity of these cells rises sharply when monkeys find themselves unable to predict whether a familiar visual signal heralds a food reward, say Christopher D. Fiorillo of the University of Fribourg in Switzerland, and his coworkers. http://www.myspace.com/louis_j_sheehan_esquire

This brain response may stimulate risky, exploratory acts in natural settings where such behaviors can reap big rewards, Fiorillo’s group theorizes. In people, they add, it may also contribute to the allure of gambling. http://www.myspace.com/louis_j_sheehan_esquire

Electrodes implanted in the brains of two adult monkeys tracked electrical responses of 188 dopamine-making neurons in an area called the midbrain. Over a series of trials, the monkeys learned to associate each of five distinctive visual patterns shown for 2 seconds on a computer screen and the probability of receiving a taste of syrup from a dropper. Specific patterns were accompanied by a dose of syrup either in all, three-quarters, half, one-quarter, or none of the presentations.

After training, dopamine neurons displayed peak electrical activity as monkeys viewed the most unpredictable pattern, which denoted a 50-50 chance of reward, the scientists report in the March 21 Science. Smaller surges in neuron activity occurred in response to patterns that predicted a reward three-quarters and one-quarter of the time. Dopamine neurons showed no response to patterns that signified certain reward or denial. Louis J. Sheehan, Esquire

No matter how hard you try to push their boundaries, black holes always seem to preserve their modesty. Indiscreet astrophysicists have simulated the most violent collisions of black holes yet, and found that the resulting black hole still has an event horizon — the surface through which even light cannot escape and that hide black holes’ interiors.

An international team of researchers created a computer simulation of what they call the most violent collision imaginable: Two black holes of equal masses smashing into each other head-on, moving at close to the speed of light.

Previous studies have suggested that when black holes collide they merge into one larger black hole, radiating huge amounts of energy in the form of gravitational waves — ripples in the very shape of space — that travel at the speed of light. This study’s results were no exception. But the extreme velocities of the team’s simulated black holes led to waves of unprecedented energy. Up to 14 percent of the black holes’ masses, instead of just a few percentage points, was converted into gravitational waves, the team reports in an upcoming Physical Review Letters.

The simulations also showed that the resulting black hole conformed to a long-standing conjecture, often attributed to Roger Penrose of the University of Oxford in England and called the cosmic censorship hypothesis.
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SIDESWIPEVIDEO | A slightly more realistic scenario in which the collision of two black holes is not exactly head-on. The result is still a black hole, including its event horizon.Sperhake et al.

Physicists believe that at the center of every black hole lies a singularity, a region where space curls up so much that the known laws of physics cease to apply, including general relativity, Albert Einstein’s theory of gravity. But a black hole’s event horizon prevents the singularity from interacting with the outside world.

Mathematically, “naked” singularities, or those without event horizons, can exist, but physicists wouldn’t know what to make of them. All known mechanisms for the formation of singularities also create an event horizon, and Penrose conjectured that there must be some physical principle — a “cosmic censor” — that forbids singularity nakedness, explains coauthor Emanuele Berti of NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “We hope it’s true,” he says of the cosmic censorship hypothesis, “because it basically hides the failures of general relativity behind the event horizon.” http://louis-j-sheehan.net

The scenario that Berti and colleagues simulated was admittedly unrealistic because real black holes would not travel at close to the speed of light. But even in such extreme conditions, the event horizon draping wasn’t lost. http://louis-j-sheehan.net

Greg Cook of Wake Forest University in Winston-Salem, N.C., says that the results are interesting, but that many questions remain. What happens, for example, when the ultrafast colliding black holes have different masses, or are rapidly spinning?

Coauthor Ulrich Sperhake, now at Caltech, says that his and other teams will keep trying to produce naked singularities, but that he doubts that they really exist. “If you ask me, ‘What am I going to put my next two salaries on?’ That Penrose was right.” Louis J. Sheehan, Esquire