Author Archives: Bora Zivkovic

Prey Not Hard-wired To Fear Predators:

Are Asian elk hard-wired to fear the Siberian tigers who stalk them” When wolves disappear from the forest, are moose still afraid of them? No, according to a study by Wildlife Conservation Society scientist Dr. Joel Berger, who says that several large prey species, including moose, caribou and elk, only fear predators they regularly encounter. If you take away wolves, you take away fear. That is a critical piece of knowledge as biologists and public agencies increase efforts to re-introduce large carnivores to places where they have been exterminated.

Electric Fish Conduct Electric Duets In Aquatic Courtship:

Cornell researchers have discovered that in the battle of the sexes, African electric fish couples not only use specific electrical signals to court but also engage in a sort of dueling “electric duet.” The study is the first to compare electrical and behavioral displays in breeding and nonbreeding Brienomyrus brachyistius, a type of mormyrid electric fish, which emit weak electric fields from a batterylike organ in their tails to sense their surroundings and communicate their species, sex and social status with other fish. It is also the first study to successfully sort signals in electric fish based on sex.

Invertebrate Immune Systems Are Anything But Simple:

A hundred years since Russian microbiologist Elie Metschnikow first discovered the invertebrate immune system, scientists are only just beginning to understand its complexity. Presenting their findings at a recent European Science Foundation (ESF) conference, scientists showed that invertebrates have evolved elaborate ways to fight disease.

Wild Sheep Descended From Single Pair Show Surprising Genetic Diversity:

Scientists at Université du Québec à Montréal have reconstructed the genetic history of a population of mouflons (wild sheep) descended from a single pair. The researchers demonstrated that the animals’ genetic diversity increased over time, contrary to what the usual models predict. These results contradict the belief that a population descended from a small number of individuals will exhibit numerous deficiencies and reduced genetic diversity.

Placental Mammals Originated On Earth 65 Million Years Ago, Researchers Assert:

An early mammal fossil discovered in Mongolia led to researchers asserting that the origins of placental mammals, which include humans, can be dated to approximately 65 million years ago in the Northern Hemisphere. These findings will be published in the June 21 issue of Nature.

Brain’s Voluntary Chain-of-command Ruled By Not One But Two Captains:

A probe of the upper echelons of the human brain’s chain-of-command has found strong evidence that there are not one but two complementary commanders in charge of the brain, according to neuroscientists at Washington University School of Medicine in St. Louis.
It’s as if Captains James T. Kirk and Jean-Luc Picard were both on the bridge and in command of the same starship Enterprise.
In reality, these two captains are networks of brain regions that do not consult each other but still work toward a common purpose — control of voluntary, goal-oriented behavior. This includes a vast range of activities from reading a word to searching for a star to singing a song, but likely does not include involuntary behaviors such as control of the pulse rate or digestion.

Why Female Deer Like A Stag To Be A Big Noise In The Forest:

Impressive antlers may be the most eye-catching attribute of the male red deer, but it’s the quality of a stag’s mating call that attracts the female of the species, a new study from the University of Sussex has discovered.

Surprising Origin Of Cell’s Internal Highways:

Scientists have long thought that microtubules, part of the microscopic scaffolding that the cell uses to move things around in order to hold its shape and divide, originated from a tiny structure near the nucleus, called the centrosome. Now, researchers at Vanderbilt University Medical Center reveal a surprising new origin for these cellular “highways.” In the June issue of Developmental Cell, Irina Kaverina, Ph.D., and colleagues report that the Golgi apparatus — a stack of pancake-shaped compartments that sorts and ships proteins out to their cellular destinations — is the source of a particular subset of these microscopic fibers. The findings point to a novel cellular mechanism that may guide cell movement and possibly cancer cell invasion.

Another Sexual Attraction Is Possible:

The coming summer vibrates with expressions of insect love and desire. The cicada’s songs or the butterflies’ bright colours are examples of how an emitting sex attracts conspecific members of the responding sex. Moth odours (pheromones), though less conspicuous for us humans, are also signals by which females guide males towards them, even on the darkest nights. Such mating recognition systems tend to be very specific, hence they are thought to play a major role in the evolution of mating barriers and in the formation of new species.

Plant Life On Extrasolar Earthlike Planets Could Be Black:

When we think of extrasolar Earth-like planets, the first tendency is to imagine weird creatures like Jar Jar Binks, Chewbacca, and, if those are not bizarre enough, maybe even the pointy-eared Vulcan, Spock, of Star Trek fame. But scientists seeking clues to life on extrasolar planets are studying various biosignatures found in the light spectrum leaking out to Earth to speculate on something more basic and essential than the musical expertise of Droopy McCool. They are speculating on what kind of photosynthesis might occur on such planets and what the extrasolar plants might look like.

What Gives Freezing Its Sting?:

Freeing knotted shoelaces with fingers that are frozen stiff is extremely difficult and can even be painful. The reason that sensitivity and dexterity are poor is that both nerves and muscles perform their tasks reluctantly when they are cold. Nevertheless ice-cold fingers ache and do so all the more in response to the lightest of knocks or squeezing.

A gazzillion new papers got published on PLoS-ONE today. Some of the titles that caught my attention and I intend to read tonight are:
The Role of the Substantia Nigra Pars Compacta in Regulating Sleep Patterns in Rats
Climate and Dispersal: Black-Winged Stilts Disperse Further in Dry Springs
The Adaptive Significance of Sensory Bias in a Foraging Context: Floral Colour Preferences in the Bumblebee Bombus terrestris
Assortative Mating between European Corn Borer Pheromone Races: Beyond Assortative Meeting
As always, do the Science 2.0 thing and post your (intelligent) questions and comments on the paper itself, either in the Discussions or the Annotations.

Are Rattlesnakes Entering Suburbia?:

A researcher for Washington University in St. Louis, along with colleagues at the Saint Louis Zoo and Saint Louis University are tracking timber rattlesnakes in west St. Louis County and neighboring Jefferson County. They are investigating how developing subdivisions invade the snakes’ turf and affect the reptiles.

Reconstructing The Biology Of Extinct Species: A New Approach:

An international research team has documented the link between the way an animal moves and the dimensions of an important part of its organ of balance, the three semicircular canals of the inner ear on each side of the skull. “We have shown that there is a fundamental adaptive mechanism linking a species’ locomotion with the sensory systems that process information about its environment,” says Alan Walker, Evan Pugh Professor of Anthropology and Biology at Penn State University, one of the team’s leaders.

Gannet Birds Under Threat From Global Warming:

Researchers at the University of Leeds have warned that global warming is a major threat to the gannet, a species known for its stable populations and constant breeding success.

Fat Fish Put Obesity On The Hook:

Everyone knows that eating lean fish helps slim waistlines, but researchers from the Center for the Study of Weight Regulation and Associated Disorders at Oregon Health and Science University in Portland, OR, have found a new way fish can help eliminate obesity. In a study to be published in the July 2007 print issue of The FASEB Journal, researchers describe the first genetic model of obesity in a fish. Having this model should greatly accelerate the development of new drugs to help people lose weight and keep it off.

Continue reading →

Science Student Gender Gap: A Continuing Challenge:

Interactive classes don’t necessarily solve the performance imbalance between the genders in physics classes, according to a new study that stands in stark contrast to previous physics education research. In fact, while students as a rule benefit from interactive classrooms, the teaching technique may even increase the imbalance in some cases.

Chad has more on this study.
Paying Taxes, According To The Brain, Can Bring Satisfaction:

Want to light up the pleasure center in your brain? Just pay your taxes, and then give a little extra voluntarily to your local food bank. University of Oregon scientists have found that doing those deeds can give you the same sort of satisfaction you derive from feeding your own hunger pangs.

Sleep Disturbances Among The Elderly Linked To Suicide:

Self-reported sleep complaints among the elderly serve as a risk factor for completed suicide, according to new research. The study, conducted by Rebecca Bernert of Florida State University, focused on data that were collected among 14,456 community elders over a 10-year period. During this time frame, 21 individuals died by suicide. When each suicide was matched to 20 randomly-selected controls, it was discovered that disturbances in sleep, independent of depression, predicted an increased risk for eventual death by suicide.

Pride May Not Come Before A Fall, After All:

The Bible got it wrong. Pride only goes before a fall when it’s hubris — excessive pride that veers into self-aggrandizement and conceit. But otherwise, this emotion is fundamental to humans and healthy self-esteem, says Psychology Asst. Prof. Jessica Tracy.

Music: Mirror Of The Mind:

The long supposed connection between mind and music has been further demonstrated by an international collaboration of physicists led by Simone Bianco and Paolo Grigolini at the Center for Nonlinear Science at the University of North Texas. A statistical analysis reveals a remarkable similarity between the distributions produced by music compositions and brain activity.

Fruit Bats Are Not ‘Blind As A Bat’:

The retinas of most mammals contain two types of photoreceptor cells, the cones for daylight vision and colour vision, and the more sensitive rods for night vision. Nocturnal bats were traditionally believed to possess only rods. Now scientists at the Max Planck Institute for Brain Research in Frankfurt and at The Field Museum for Natural History in Chicago have discovered that nocturnal fruit bats (flying foxes) possess cones in addition to rods. Hence, fruit bats are also equipped for daylight vision. The researchers conclude that cone photoreceptors might be useful for spotting predators and for social interactions at periods of roosting during the day. Flying foxes often use exposed treetops as daytime roosts, where they assemble in large colonies (Brain, Behavior and Evolution, online May 2007).

Disappearing Common Birds Send Environmental Wake-up Call:

Birdsongs that filled the childhoods of countless baby-boomers are rarely heard wafting on today’s spring breezes….Once-familiar avian spectacles now elude young birdwatchers…It’s not your imagination… A new analysis by the National Audubon Society reveals that populations of some of America’s most familiar and beloved birds have taken a nosedive over the past forty years, with some down as much as 80 percent. The dramatic declines are attributed to the loss of grasslands, healthy forests and wetlands, and other critical habitats from multiple environmental threats such as sprawl, energy development, and the spread of industrialized agriculture.

Whale Has Super-sized Big Gulp:

How does the largest animal on earth survive on a diet of the smallest of prey? By having a jaw that spans a quarter of its body length, an enormous mouth that goes from the head to the belly button, and by doing lots of “lunges,” according to UBC zoology PhD candidate Jeremy Goldbogen.

Bacteria Can Hide Out In Cells For Weeks:

A major cause of human and animal infections, Staphylococcus aureus bacteria may evade the immune system’s defences and dodge antibiotics by climbing into our cells and then lying low to avoid detection. New research shows how S. aureus makes itself at home in human lung cells for up to two weeks.

Single-celled Transformers: Marine Phytoplankton Changes Form To Protect Itself:

A tiny single-celled organism that plays a key role in the carbon cycle of cold-water oceans may be a lot smarter than scientists had suspected. Researchers report the first evidence that a common species of saltwater algae — also known as phytoplankton — can change form to protect itself against attack by predators that have very different feeding habits.