Friday, September 4, 2009

WORLD'S LAST GREAT FOREST UNDER THREAT

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The world's last remaining "pristine" forest - the boreal forest across large stretches of Russia, Canada and other northern countries - is under increasing threat, a team of international researchers has found.

The researchers from the University of Adelaide in Australia, Memorial University of Newfoundland in Canada and the National University of Singapore have called for the urgent preservation of existing boreal forests in order to secure biodiversity and prevent the loss of this major global carbon sink.

The boreal forest comprises about one-third of the world's forested area and one-third of the world's stored carbon, covering a large proportion of Russia, Canada, Alaska and Scandinavia.

To date it has remained largely intact because of the typically sparse human populations in boreal regions. That is now changing says researchers and co-authors Associate Professor Corey Bradshaw, University of Adelaide, Associate Professor Ian Warkentin, Memorial University, and Professor Navjot Sodhi, National University of Singapore.

"Much world attention has focused on the loss and degradation of tropical forests over the past three decades, but now the boreal forest is poised to become the next Amazon," says Associate Professor Bradshaw, from the University of Adelaide's Environment Institute.

"Historically, fire and insects have driven the natural dynamics of boreal ecosystems," says Associate Professor Warkentin. "But with rising demand for resources, human disturbances caused by logging, mining and urban development have increased in these forests during recent years, with extensive forest loss for some regions and others facing heavy fragmentation and exploitation."

The findings have been published online in Trends in Ecology and Evolution in a paper called `Urgent preservation of boreal carbon stocks and biodiversity'. The findings include:

-Fire is the main driver of change and increased human activity is leading to more fires. There is also evidence that climate change is increasing the frequency and possibly the extent of fires in the boreal zone.

-Few countries are reporting an overall change in the coverage by boreal forest but the degree of fragmentation is increasing with only about 40% of the total forested area remaining "intact".

-Russian boreal forest is the most degraded and least "intact" and has suffered the greatest decline in the last few decades.

-Countries with boreal forest are protecting less than 10% of their forests from timber exploitation, except for Sweden where the figure is about 20%.

(Photo: U. Adelaide)

University of Adelaide

TRUST IN A TEARDROP

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Medically, crying is known to be a symptom of physical pain or stress. But now a Tel Aviv University evolutionary biologist looks to empirical evidence showing that tears have emotional benefits and can make interpersonal relationships stronger.

New analysis by Dr. Oren Hasson of TAU's Department of Zoology shows that tears still signal physiological distress, but they also function as an evolution-based mechanism to bring people closer together.

"Crying is a highly evolved behavior," explains Dr. Hasson. "Tears give clues and reliable information about submission, needs and social attachments between one another. My research is trying to answer what the evolutionary reasons are for having emotional tears.

"My analysis suggests that by blurring vision, tears lower defences and reliably function as signals of submission, a cry for help, and even in a mutual display of attachment and as a group display of cohesion," he reports.

His research, published recently in Evolutionary Psychology, investigates the different kinds of tears we shed — tears of joy, sadness and grief — as well as the authenticity or sincerity of the tears. Crying, Dr. Hasson says, has unique benefits among friends and others in our various communities.

Approaching the topic with the deductive tools of an evolutionary biologist, Dr. Hasson investigated the use of tears in various emotional and social circumstances. Tears are used to elicit mercy from an antagonistic enemy, he claims. They are also useful in eliciting the sympathy — and perhaps more importantly the strategic assistance — of people who were not part of the enemy group.

"This is strictly human," reasons Dr. Hasson. "Emotional tears also signal appeasement, a need for attachment in times of grief, and a validation of emotions among family, friends and members of a group."

Crying enhances attachments and friendships, says Dr. Hasson, but taboos are still there in certain cases. In some cultures, societies or circumstances, the expression of emotions is received as a weakness and the production of tears is suppressed. For example, it is rarely acceptable to cry in front of your boss at work — especially if you are a man, he says.

Multiple studies across cultures show that crying helps us bond with our families, loved ones and allies, Dr. Hasson says. By blurring vision, tears reliably signal your vulnerability and that you love someone, a good evolutionary strategy to emotionally bind people closer to you.

"Of course," Dr. Hasson adds, "the efficacy of this evolutionary behavior always depends on who you're with when you cry those buckets of tears, and it probably won't be effective in places, like at work, when emotions should be hidden."

Dr. Hasson, a marriage therapist, uses his conclusions in his clinic. "It is important to legitimize emotional tears in relationships," he says. "Too often, women who cry feel ashamed, silly or weak, when in reality they are simply connected with their feelings, and want sympathy and hugs from their partners."

(Photo: TAU)

Tel Aviv University

SCIENTISTS DISCOVER NEW SPECIES OF CRUSTACEAN ON LANZAROTE

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Diving expedition in lava tube finds remarkable new specimens. They gracefully swim through the complete darkness of submarine caves, constantly on the lookout for prey. Instead of eyes, predatory crustaceans of the class Remipedia rely on long antennae which search the lightless void in all directions. Like some type of science fiction monster, their head is equipped with powerful prehensile limbs and poisonous fangs.

Accordingly, the translations of their Latin names sound menacing. There is the "Secret Club Bearer" (Cryptocorynetes) or the "Beautiful Hairy Sea Monster" (Kaloketos pilosus). The names of some genera were inspired by Japanese movie monsters, for example, the "Swimming Mothra” (Pleomothra), the "Strong Godzilla" (Godzillius robustus) or the "Gnome Godzilla" (Godzilliognomus).

During a cave diving expedition to explore the Tunel de la Atlantida, the world’s longest submarine lava tube on Lanzarote in the Canary Islands, an international team of scientists and cave divers have discovered a previously unknown species of crustacean, belonging to the remipede genus Speleonectes, and two new species of annelid worms of the class Polychaeta.

The team consisted of scientists from Texas A&M University and Pennsylvania State University in the U.S., the University of La Laguna in Spain, and the University of Veterinary Medicine Hannover and University of Hamburg, both in Germany. The extensive results of the Atlantida Diving Expedition will be presented in a special issue of the Springer journal Marine Biodiversity, comprising seven articles, to be published in September 2009.

The newly discovered species of Remipedia was named Speleonectes atlantida, after the cave system it inhabits. It is morphologically very similar to Speleonectes ondinae, a remipede that has been known from the same lava tube since 1985. Based on DNA comparisons, the group of Prof. Stefan Koenemann from the Institute for Animal Ecology and Cell Biology of TiHo Hannover conclusively proved that the lava tunnel harbors a second remipede species. The divergence of the two species may have occurred after the formation of the six-kilometer lava tube during an eruption of the Monte Corona volcano some 20,000 years ago.

Remipedia are among the most remarkable biological discoveries of the last 30 years. The first specimens of this crustacean group were discovered in 1979 during dives in a marine cave system on Grand Bahama in the Bahamas archipelago. Since then, 22 species of Remipedia have been discovered. The main distribution area of the cave-limited group extends from the Yucatan Peninsula in Mexico, through the northeastern Caribbean. However, two geographically isolated species inhabit caves in Western Australia and Lanzarote.

The occurrence of these disjunct species has continues to give rise to speculation about the evolutionary origins and history of Remipedia. Since it is assumed that the relatively small (largest specimens are up to four centimeters long) and eyeless cave-dwellers could not cross an entire ocean by actively swimming, there must be other reasons for their disjunct global distribution. It has therefore been suggested that Remipedia are a very ancient crustacean group, which was already widespread in the oceans of the Mesozoic, over 200 million years ago. For these reasons, remipedes are often considered as a primeval group of crustaceans.

According to this evolutionary scenario, the newly discovered species Speleonectes atlantida and the previously known species Speleonectes ondina, both occurring in the undersea lava tube on Lanzarote, would represent ancient relicts that became isolated from the main Caribbean group during the formation of the Atlantic Ocean.

(Photo: Springer)

CLUES TO GIGANTISM PROVIDED BY FAMILY IN BORNEO MOUNTAINS

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An indigenous family living in a mountainous area of Malaysian Borneo helped Van Andel Research Institute (VARI) researchers to discover information about genetic mutations associated with acromegaly, a form of gigantism that often results in enlarged hands, feet, and facial features.

The information could lead to better screening for the disease, which most often results from a benign pituitary gland tumor that can be deadly if left untreated, but which is difficult to detect until later stages when features become pronounced.

Researchers located a 31-member aboriginal family that included individuals with acromegaly living in a mountainous region of Borneo, Malaysia when the effects of the family patriarch’s growing pituitary tumor necessitated medical treatment. A medical team including VARI Distinguished Scientific Investigator Bin Tean Teh, M.D., Ph.D., and staff from the Department of Medicine at the University of Malaya Medical Centre and the Department of Medicine at the Queen Elizabeth Hospital in Malaysia subsequently traveled to the family’s village several times to collect blood samples for testing.

“Researchers had recently found a mutation in the AIP gene associated with acromegaly,” said Dr. Teh, “but we found that several family members who didn’t have visible symptoms of acromegaly had this mutation as well. This increases the importance of screening for families with cases of acromegaly since anyone could be a carrier. On one side of the family, at least two generations carried the gene before someone showed any symptoms.”

The later stages of acromegaly often produce enlarged hands and feet, protruding brows and lower jaws, thick voice and slowed speech from swelling of vocal cords, and other symptoms. When diagnosed, the tumor and entire pituitary gland are usually removed, followed by hormone therapy for the rest of the patient’s life. However, because the progression of the disease is so gradual, it is difficult to detect. If left unchecked, patients can die from complications such as heart or kidney failure. Well-known acromegalics include wrestler-actor André the Giant and motivational speaker Tony Robbins.

VARI Research Scientist and lead author of the study Sok Kean Khoo, Ph.D., led researchers in scanning DNA in the family’s blood to find other factors that might explain why only some family members with the genetic mutation had visible symptoms of the disease. They found regions on a few chromosomes that might lead to further insight; these findings were published this week in the journal Endocrine-Related Cancer.

The prevalence of acromegaly is approximately 4,676 cases per million population, and the incidence is approximately 117 new cases per million per year. However, Dr. Khoo said that the recent findings may mean that the prevalence is higher since carriers of the genetic mutation who do not have symptoms are not included.

“The sooner we know how and why people are affected differently by this disease, the sooner we can help families who have it,” said Dr. Teh. “One of the women in this family was only 19 and probably thought that since her grandfather had lived so long with the disease, she would too. She chose not to go to the hospital for treatment and, sadly, died two years after our last visit.”

Van Andel Research Institute

EVOLUTION OF THE APPENDIX: A BIOLOGICAL 'REMNANT' NO MORE

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The lowly appendix, long-regarded as a useless evolutionary artifact, won newfound respect two years ago when researchers at Duke University Medical Center proposed that it actually serves a critical function. The appendix, they said, is a safe haven where good bacteria could hang out until they were needed to repopulate the gut after a nasty case of diarrhea, for example.

Now, some of those same researchers are back, reporting on the first-ever study of the appendix through the ages. Writing in the Journal of Evolutionary Biology, Duke scientists and collaborators from the University of Arizona and Arizona State University conclude that Charles Darwin was wrong: The appendix is a whole lot more than an evolutionary remnant. Not only does it appear in nature much more frequently than previously acknowledged, but it has been around much longer than anyone had suspected.

"Maybe it's time to correct the textbooks," says William Parker, Ph.D., assistant professor of surgical sciences at Duke and the senior author of the study. "Many biology texts today still refer to the appendix as a 'vestigial organ.'"

Using a modern approach to evolutionary biology called cladistics, which utilizes genetic information in combination with a variety of other data to evaluate biological relationships that emerge over the ages, Parker and colleagues found that the appendix has evolved at least twice, once among Australian marsupials and another time among rats, lemmings and other rodents, selected primates and humans. "We also figure that the appendix has been around for at least 80 million years, much longer than we would estimate if Darwin's ideas about the appendix were correct."

Darwin theorized that the appendix in humans and other primates was the evolutionary remains of a larger structure, called a cecum, which was used by now- extinct ancestors for digesting food. The latest study demonstrates two major problems with that idea. First, several living species, including certain lemurs, several rodents and a type of flying squirrel, still have an appendix attached to a large cecum which is used in digestion. Second, Parker says the appendix is actually quite widespread in nature. "For example, when species are divided into groups called 'families', we find that more than 70 percent of all primate and rodent groups contain species with an appendix." Darwin had thought that appendices appeared in only a small handful of animals.

"Darwin simply didn't have access to the information we have," explains Parker. "If Darwin had been aware of the species that have an appendix attached to a large cecum, and if he had known about the widespread nature of the appendix, he probably would not have thought of the appendix as a vestige of evolution."

He also was not aware that appendicitis, or inflammation of the appendix, is not due to a faulty appendix, but rather due to cultural changes associated with industrialized society and improved sanitation. "Those changes left our immune systems with too little work and too much time their hands – a recipe for trouble," says Parker.

That notion wasn't proposed until the early 1900's, and "we didn't really have a good understanding of that principle until the mid 1980's," Parker said. "Even more importantly, Darwin had no way of knowing that the function of the appendix could be rendered obsolete by cultural changes that included widespread use of sewer systems and clean drinking water."

Parker says now that we understand the normal function of the appendix, a critical question to ask is whether we can do anything to prevent appendicitis. He thinks the answer may lie in devising ways to challenge our immune systems today in much the same manner that they were challenged back in the Stone Age. "If modern medicine could figure out a way to do that, we would see far fewer cases of allergies, autoimmune disease, and appendicitis."

Duke University Medical Center

WHY SLEEP? UCLA SCIENTIST DELVES INTO ONE OF SCIENCE'S GREAT MYSTERIES

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According to the journal Science, the function of sleep is one of the 125 greatest unsolved mysteries in science. Theories range from brain "maintenance" — including memory consolidation and pruning — to reversing damage from oxidative stress suffered while awake, to promoting longevity. None of these theories are well established, and many are mutually exclusive.

Now, a new analysis by Jerome Siegel, UCLA professor of psychiatry and director of the Center for Sleep Research at the Semel Institute for Neuroscience and Human Behavior at UCLA and the Sepulveda Veterans Affairs Medical Center, has concluded that sleep's primary function is to increase animals' efficiency and minimize their risk by regulating the duration and timing of their behavior.

The research appears in the current online edition of the journal Nature Reviews Neuroscience.

"Sleep has normally been viewed as something negative for survival because sleeping animals may be vulnerable to predation and they can't perform the behaviors that ensure survival," Siegel said. These behaviors include eating, procreating, caring for family members, monitoring the environment for danger and scouting for prey.

"So it's been thought that sleep must serve some as-yet unidentified physiological or neural function that can't be accomplished when animals are awake," he said.

Siegel's lab conducted a new survey of the sleep times of a broad range of animals, examining everything from the platypus and the walrus to the echidna, a small, burrowing, egg-laying mammal covered in spines. The researchers concluded that sleep itself is highly adaptive, much like the inactive states seen in a wide range of species, starting with plants and simple microorganisms; these species have dormant states — as opposed to sleep — even though in many cases they do not have nervous systems. That challenges the idea that sleep is for the brain, said Siegel.

"We see sleep as lying on a continuum that ranges from these dormant states like torpor and hibernation, on to periods of continuous activity without any sleep, such as during migration, where birds can fly for days on end without stopping," he said.

Hibernation is one example of an activity that regulates behavior for survival. A small animal, Siegel noted, can't migrate to a warmer climate in winter. So it hibernates, effectively cutting its energy consumption and thus its need for food, remaining secure from predators by burrowing underground.

Sleep duration, then, is determined in each species by the time requirements of eating, the cost-benefit relations between activity and risk, migration needs, care of young, and other factors. However, unlike hibernation and torpor, Siegel said, sleep is rapidly reversible — that is, animals can wake up quickly, a unique mammalian adaptation that allows for a relatively quick response to sensory signals.

Humans fit into this analysis as well. What is most remarkable about sleep, according to Siegel, is not the unresponsiveness or vulnerability it creates but rather that ability to reduce body and brain metabolism while still allowing that high level of responsiveness to the environment.

"The often cited example is that of a parent arousing at a baby's whimper but sleeping through a thunderstorm," he said. "That dramatizes the ability of the sleeping human brain to continuously process sensory signals and trigger complete awakening to significant stimuli within a few hundred milliseconds."

In humans, the brain constitutes, on average, just 2 percent of total body weight but consumes 20 percent of the energy used during quiet waking, so these savings have considerable adaptive significance. Besides conserving energy, sleep invokes survival benefits for humans too — "for example," said Siegel, "a reduced risk of injury, reduced resource consumption and, from an evolutionary standpoint, reduced risk of detection by predators."

"This Darwinian perspective can explain age-related changes in human sleep patterns as well," he said. "We sleep more deeply when we are young, because we have a high metabolic rate that is greatly reduced during sleep, but also because there are people to protect us. Our sleep patterns change when we are older, though, because that metabolic rate reduces and we are now the ones doing the alerting and protecting from dangers."

UCLA

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