ancestors

Wild chimpanzees have taken a bite out of scientific assumptions about the growth rate of one of our most prominent Stone Age relatives.

New measurements of dental-growth rates of wild chimpanzees provide a more accurate benchmark for estimating comparably slow growth in Homo erectus teeth, say Adrienne Zihlman of the University of California, Santa Cruz and her colleagues.

"Our data suggest that wild chimpanzees and Homo erectus didn't differ from each other as much as previously thought," Zihlman says.

The relatively quick tooth growth in captive chimps has typically been contrasted with the slower tooth development in human ancestors. However, dental growth occurs much more slowly in wild chimps than in their captive comrades, the researchers report in the July 20 Proceedings of the National Academy of Sciences.http://louis-j-sheehan.info

Zihlman's team examined skeletal samples from 18 wild chimpanzees of known ages, ranging from 1.8 to 16.5 years. For these animals, infancy lasted until about 4 years of age and dental maturity occurred between 12 and 13 years. In captive chimps, infancy ends at around age 3 and maturity is reached at about age 10.http://louis-j-sheehan.info

This discovery challenges the view that evolution proceeded gradually from a fast-growing chimplike ancestor around 8 million years ago to a slower-growing H. erectus, which lived from about 1.6 million to 400,000 years ago, and then to an even slower-developing Homo sapiens.

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legs

Two new lines of evidence bolster the claim that the oldest known member of the human-evolutionary family lived in central Africa between 6 million and 7 million years ago.Louis J. Sheehan

In 2001, at a site in Chad, anthropologist Michel Brunet of the University of Poitiers in France and his coworkers found jaw fragments, isolated teeth, and the nearly complete skull of a creature that the researchers identified as a hominid and assigned to the category Sahelanthropus tchadensis. The skull combines a cranium suitable for a chimp-size brain with facial and tooth structures resembling those of later human ancestors (SN: 7/13/02, p. 19: http://www.sciencenews.org/articles/20020713/fob1.asp).

After the discovery, a group of researchers led by Milford H. Wolpoff of the University of Michigan in Ann Arbor initiated a controversy by contending that Sahelanthropus looks more like a fossil ape than a hominid (SN: 10/19/02, p. 253: Available to subscribers at http://www.sciencenews.org/articles/20021019/note12.asp).

Brunet's team now reports the discovery of two more jaw pieces and another tooth from Sahelanthropus. The researchers unearthed the specimens in Chad at three locations, including the site of the prior finds.

The new fossils cement Sahelanthropus' position as a hominid that lived shortly after modern humans' evolutionary family diverged from chimpanzee ancestors, the scientists argue in the April 7 Nature.

In an accompanying paper, Brunet and his colleagues—with Christoph P.E. Zollikofer of the University of Zurich—present a computerized, three-dimensional reconstruction of the ancient creature's skull. The digital version corrects crushed sections of the actual fossil.http://ljsheehan.livejournal.com

"This is a state-of-the-art technique for taking a squished specimen and putting it back together digitally," remarks Tim White of the University of California, Berkeley. White regards the Chad fossils as those of a hominid. Only further discoveries can establish whether Sahelanthropus represented a separate genus or belonged to a previously identified group of nearly 6-million-year-old African hominids dubbed Ardipithecus, he says.

However they're labeled, the new fossils exhibit key hominid traits, Brunet holds. For instance, one jaw piece retains a canine tooth that's smaller than the teeth of chimps but comparable to those of hominids that came after Sahelanthropus. Some newfound cheek teeth also contain thinner enamel layers than corresponding teeth from chimps do.

The virtual skull further establishes Sahelanthropus' hominid status, in Brunet's view. It features a relatively flat face and a forward-positioned opening for the spinal cord, both typical hominid characteristics. The angle of the creature's neck was similar to that of later hominids that are known to have walked upright, the scientists say.

More-revealing tests of the ancient creature's walking behavior await the discovery of fossils from its legs, pelvis, and feet.http://ljsheehan.livejournal.com

The new reports leave Michigan's Wolpoff unconvinced that Sahelanthropus was a hominid. The jaws and teeth of apes and early hominids look much alike, so the new fossil finds don't clarify the creature's evolutionary identity, he says.

Moreover, the reconstructed skull contains bony attachments for neck muscles that were far too large to accommodate a regular upright stance, Wolpoff says. Neck muscles of that size might have attached to unusually long arms on a ground-dwelling ape, not a hominid, he suggests.

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activity

Relationships too often end with feelings of hurt, longing, and craving. A new study suggests that scientists can see those emotions reflected in brain images of lovers who were recently spurned.

Three years ago, Lucy Brown of Albert Einstein College of Medicine in New York and her colleagues identified brain areas that seem to be active when someone is happily in love. In the new study, the researchers recruited 17 women and men who were unhappy about being recently dumped by a partner.

The team scanned the brains of the volunteers as each one viewed a picture of his or her former sweetheart and a photo of an emotionally neutral acquaintance. To cleanse their brains of strong emotions between photos, the subjects counted backward in increments of seven.

The researchers found that the brains of these rejected lovers behaved differently than those of the contented lovers in the previous study. When viewing pictures of their beloveds, people in both groups showed increased activity in brain areas associated with rewards. However, spurned lovers showed more activity in the nucleus accumbens and the ventral striatum, regions associated with evaluating risks and sizing up payoffs when gambling. Rejected lovers also had more activity in the insular cortex, a brain region associated with physical pain and anxiety.http://www.blog.ca/user/Beforethebigbang

Brown notes that the findings may explain the visceral pain that many people feel after a rejection. Brain activity associated with gambling could clarify why some people choose to pursue a loved one after a breakup, even when the payoff is uncertain, she says. "To the rejected person, love is the greatest prize," says Brown

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positive

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People with generally positive outlooks show greater resistance to developing colds than do individuals who rarely revel in upbeat feelings, a new investigation finds.

Frequently basking in positive emotions defends against colds regardless of how often one experiences negative emotions, say psychologist Sheldon Cohen of Carnegie Mellon University in Pittsburgh and his colleagues। They suspect that positive emotions stimulate symptom-fighting substances. http://louis3j3sheehan.blogspot.com

"We need to take more seriously the possibility that a positive emotional style is a major player in disease risk," Cohen says.

In a study published in 2003, his group exposed 334 healthy adults to one of two rhinoviruses via nasal drops. Those who displayed generally positive outlooks, including feelings of liveliness, cheerfulness, and being at ease, were least likely to develop cold symptoms. Unlike the negatively inclined participants, they reported fewer cold symptoms than were detected in medical exams.

The new study, which appears in the November/December Psychosomatic Medicine, replicates those results and rules out the possibility that psychological traits related to a positive emotional style, rather than the emotions themselves, guard against cold symptoms. Those traits include high self-esteem, extroversion, optimism, and a feeling of mastery over one's life.

The latest data also show that among people with a consistently positive mood, well-being doesn't simply reflect physical vigor. All volunteers entered the study in comparably good health.

In that project, Cohen's team interviewed 193 healthy adults by phone each evening for 2 weeks। The participants reported their positive and negative emotions during that day. They then received nasal drops containing a rhinovirus or an influenza virus that causes a coldlike illness. http://louis3j3sheehan.blogspot.com

Each person was quarantined in a separate room and monitored for 5 or 6 days. Although a positive emotional style bore no relation to whether participants became infected, it protected against the emergence of cold symptoms. For instance, among people infected by the influenza virus, 14 of 50 (28 percent) who often reported positive emotions developed coughs, congestion, and other cold symptoms, as compared with 23 of 56 infected individuals (41 percent) who rarely reported positive emotions.

The extent of positive emotions, but not of negative ones, exerted a strong impact on the emergence of cold symptoms, Cohen says. His recent analysis of immune measures from volunteers in the 2003 study, published last March in Brain, Behavior, and Immunity, points to enhanced regulation of an infection-fighting substance, interleukin-6, in people with positive emotional styles.

Cohen's current study offers "an interesting twist" on the relationship between feelings and health, remarks psychologist Janice K। Kiecolt-Glaser of Ohio State University in Columbus। Other research indicates that negative emotions influence immune function and illness development more powerfully than positive emotions do, Kiecolt-Glaser says. http://louis3j3sheehan.blogspot.com

However, psychologist Barbara L। Fredrickson of the University of North Carolina at Chapel Hill notes that the new data agree with her work showing that to a surprising degree, positive emotions can bolster the immune system to improve health। http://louis3j3sheehan.blogspot.com

Studies of the impact of mood on physical health need to account for both positive and negative emotions, Cohen holds. He points to preliminary data from other teams suggesting that among depressed people, a lack of positive emotions is a more accurate predictor of stroke than is the extent of their negative emotions.

irony

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Global warming may turn out to be more than just a pain in the neck: Rising average temperatures might trigger an increased prevalence of kidney stones। http://louisyjysheehan.blogspot.com

About 12 percent of men and 7 percent of women in the United States will be stricken during their lifetime with symptoms of a kidney stone, which forms when minerals dissolved in urine crystallize somewhere in the kidney or urinary tract.

One of the primary causes of these painful deposits is low urine volume, brought about either by low fluid intake or by increased fluid loss, says Margaret S. Pearle, a urologist at the University of Texas Southwestern Medical Center at Dallas.

Although people in all parts of the nation can suffer kidney stones, the ailment is much more common in some regions than in others.

Prevalence of stones in the Southeast is as much as 50 percent higher than it is the Northwest, Pearle says. Urologists have long known of a “kidney stone belt,” which stretches from the Carolinas through Texas to southern and central California, she notes.

Overall, differences in average annual temperature among various U.S. regions account for about 70 percent of the variation in kidney stone prevalence. Dramatic increases in the ailment among soldiers deployed to arid regions, as well as seasonal variations in frequency of the malady, bolster the link between temperature and prevalence, the researchers propose.

Now, in the July 15 Proceedings of the National Academy of Sciences, Pearle and her colleagues estimate how the prevalence of kidney stones — and the costs needed to treat them — might increase as climate change boosts average temperatures.

In one climate change scenario —in which the atmospheric concentrations of carbon dioxide rise to 850 parts per million by 2100, up from about 380 ppm today — average annual temperature in some parts of the United States would rise as much as 3।25 degrees Celsius, says Tom H। Brikowski, a hydrologist at the University of Texas at Dallas and coauthor of the paper.http://louisyjysheehan.blogspot.com

Under such a scenario, kidney stone prevalence will undoubtedly rise. However, Pearle notes, the specific relation between average annual temperature and prevalence isn’t clear. While some urologists suggest that an increase in temperature will lead to a proportional increase in kidney stone prevalence, others propose that above a certain temperature threshold — say, 15° C — the risk of developing stones doesn’t increase.

In the model where the risk of stones rises proportionally with an increase in average annual temperature, the largest bumps in kidney stone cases by the year 2050 are concentrated in California, Texas, Florida and the East Coast, the researchers report. Under the other model, the increase in kidney stone prevalence over that period would be largely confined to Northern California and a swath running from Kansas to Virginia, because the average annual temperature in much of the Southeast already sits above 15° C. In some regions, kidney stone prevalence could rise about 30 percent, the analysis suggests.

Between now and 2050, climate change could cause an additional 1.6 million to 2.2 million cases of kidney stones, the researchers speculate. At that time, annual medical costs for stone-related emergency room visits, out-patient appointments and surgery would run between 900 million and 1.3 billion year-2000 dollars, the researchers estimate.

“These costs are pretty staggering,” says Anthony Smith, a urologist at the University of New Mexico in Albuquerque। He describes the new research as “a fascinating study … that indicates climate-related changes in the environment will have large economic and human costs।” http://louisyjysheehan.blogspot.com

The new research “is really a seminal piece of work,” says Mark S. Litwin, a urologist at the University of California, Los Angeles. Kidney stones are one of the largely unrecognized — and largely preventable — consequences of climate change, he adds.

More aggressive efforts to maximize hydration could result in a decreased incidence of stone problems, says Ira Sharlip, a urologist in San Francisco.

Litwin agrees: “The irony is, the cure is fairly simple,” he notes. “Just drink more water.”

bragg

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MAY 26TH—Sunshine and showers.

Senator Henry’s letter was referred to Gen. Bragg, who returned it to-day with the indorsement that the suggested movement had not escaped attention, and a good result might soon be looked for. And sure enough, a dispatch was received from Atlanta to-day, announcing the capture of some 250 of the enemy’s wagons laden with stores! http://louis0j0sheehan.blogspot.com

It is to be hoped that Gen। Lee has some scheme of a similar character, to relieve Grant of his supply trains. Troops are daily coming hither, infantry and cavalry, whence in one hour and a half the former reach Lee’s army. The great battle still hangs fire, but to be of greater magnitude when it does occur. http://louis0j0sheehan.blogspot.com

Gen. Bragg did a good thing yesterday, even while Senator Orr was denouncing him. He relieved Gen. Winder from duty here, and assigned him to Goldsborough, N. C. Now if the rogues and cut-throats he persisted in having about him be likewise dismissed, the Republic is safe! Gen. Ransom has now full charge of this department.

Mr. Secretary Seddon is sick, and Mr. Assistant Secretary Campbell is crabbed—Congress not having passed his Supreme Court bill. And if it were passed, the President would hardly appoint him judge.

It is said one of our iron-clads is out—the rest to follow immediately. Let Butler beware!

packard

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Michael R. Nash writes, in a july 2001 article for Scientific American titled "The Truth and the Hype of Hypnosis", "using hypnosis, scientists have temporarily created hallucinations, compulsions, certain types of memory loss, false memories, and delusions in the laboratory so that these phenomena can be studied in a controlled environment."http://louis1j1sheehan.us

In his book The Hidden Persuaders (1957) Vance Packard describes research involving the behavior of housewives in supermarkets in the 1950s. Cameras were hidden to measure a shopper's eye-blink rate as she compared items. http://louis1j1sheehan.usIt was assumed that her eye-blink rate would increase as she performed mental calculations to determine which product was the best value. In fact, the cameras recorded an eye-blink rate which indicated that the housewife was, according to Packard, usually in a hypnotic state while shopping. This led manufacturers to produce new brands of laundry detergent in competition with their own, existing brands, where the primary differences were in the product names, colors and shapes of designs on the packages, which were designed to appeal to women at different times of their menstrual cycles. The effects of this research can be noted today by visiting the laundry detergent section of any American supermarket.[

Hypnotism has also received publicity about its use in Forensics, Sports, Education, and physical therapy and rehabilitation.