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(03/14/12 5:00am)
Anyone on the Hopkins Emergency Response Unit - or at a college party, for that matter - has probably seen their fair share of drunk kids puking their guts out. People vomit for a wide variety of reasons; maybe they have the flu, maybe the biochemistry test was upsetting to the stomach, or perhaps riding a roller-coaster gave their stomach the flip-flops. While highly unpleasant, vomiting is actually quite an important adaptation. Ever wonder why rats take tiny bites all the time? That's because rats lack the ability to vomit, so they have to take extra care to not swallow any toxins. Surprisingly, humans are not the only organisms that unload their stomachs as a result of environmental stimuli. Researchers at the Estaci??n Experimental de Zonas ??ridas, CSIC, recently found that baby Eurasian rollers (a bird species) spew a smelly orange liquid when scared by predators, an adaptive signal that warns parents to stay away from the nest. At a glance, the behaviors of these self-sacrificing babies seem to be evolutionarily counterproductive. After all, isn't survival of the youngsters critical to perpetuating the species? Not, as behavioral research indicates, if the birds are long-lived. According to researcher Deseada Parejo, parental birds must weigh the benefits of their own survival against those of defending their nestlings. In the animal world, parental love is truly conditional - virtually every parenting decision is made in an attempt to improve the individual's net reproductive success. The algorithm is quite simple: when you are a short-lived bird, such as the quail, you have few opportunities to mate and produce viable offspring. Given the threat of many predators, such as hawks, snakes and foxes, the quails are more likely to prioritize the safety of their young above your own survival. By contrast, Eurasian rollers have a longer life span, so they have multiple opportunities to mate and do not have to prioritize the safety of their young. These parenting behaviors may seem heartless and brutal to us, but that's just how the animal world works - survival of the fittest. When it comes to sex, birds are no less ambitious. The image of the monogamous bird is mostly just an illusion. Most, if not all, songbirds would start an affair with a handsome stranger if their current mate is, genetically speaking, a loser. Known scientifically as Coracias garrulous, Eurasian rollers are beautiful birds, with violet and turquoise plumage and chestnut-brown backs. They are solitary outside the mating season and prevail in many parts of the world, including Europe, Asia, the Middle East and Africa. See BIRDS, Page B9 BIRDS, From B7 In attempt to better understand their unique vomiting adaptation, the researchers recruited rollers from nests in breeding boxes in southeastern Spain. The subjects, 15 nests of baby birds no older than 10 days old, were observed for half a day. Then, the researchers applied either baby bird vomit or lemon scent to the bird nests and continued their observation for another 100 minutes. A researcher under the single-blind condition counted how quickly and often parents returned to the nest boxes. As you might expect, vomit-coated birds do not make a tasty snack, and predators and bird parents alike are not very willing to get near the odorous hatchlings. When vomit was applied to the nests, the parents delayed their visit to the nest for about 27 minutes and skipped two regular feeding visits during the first 20 minutes of observation. It took almost 100 minutes for the birds to fully conquer their "vomit-smell" fear. Conversely, the lemon scent caused the opposite effect, increasing the frequency of nest visits. For the rollers, bird vomit signals fear and alerts the parents of a disturbance at the nest. To us, this would be equivalent to seeing our apartment door open when we come home from class, suggesting that a stranger has been in our house. According to Parejo, birds use olfactory cues in several biologically relevant contexts, including orientation, navigation, prey detection and recognition of conspecifics. As rollers tend to dwell in dark places, they may be more likely than other birds to utilize scented cues. The researchers must have had a hard time working with the birds because they vomit when handled by humans, a sign that vomiting may also have a defensive function. Interestingly, Eurasian rollers are not the only birds who regurgitate their lunches under pressure. Study leader Parejo says that the phenomenon is not common in birds, but the adult Northern Fulmars, Fulmaris glacialis, has been known to use its digestive enzymes against intruders. The behavior is actually more common in other animals - many arthropods lose their lunches when disturbed. Even in humans, vomit has its use as a defensive mechanism. Scientists believe that incredibly nauseating phenomenon of chain-vomiting is an evolved trait in primates. The reason behind this is quite clear: if a member in your early human hunting party consumes a toxic animal or plant, it would do well for other party members to not befall the same fate. While the unfortunate taster may not live to pass on his or her genes, the people around him or her get the benefit of blacklisting whatever morsel that person swallowed. Just because vomiting useful, though, does not mean that it is particularly pleasant. According to an online survey conducted by the University of Salford's Acoustic Research Centre, most people find the sound of vomiting "the most disgusting." ?
(03/07/12 5:00am)
Ever since its discovery in 1905, the infamous Tyrannosaurus rex has attained a celebrity status that is unique among dinosaurs. While larger and more ruthless dinosaurs have since been discovered, T. rex and his famished companions, the Allosaurus and Velociraptor, continue to secure leading roles in films such as Jurassic Park, Night of the Museum and Ice Age: Dawn of the Dinosaurs.
(02/22/12 5:00am)
The origin of zebra stripes has long been a subject of creation myths and scientific debate. From an evolutionary perspective, the first answer that probably comes to mind is camouflage. The zebra's bold patterns are a mixed blessing: when stationary, the contrasting black and white stripes offer little protection from the prying eyes of lions. This explains why zebras seek safety in numbers - the occasional loss of an animal is offset by the benefits of a herd-wide predator detection system. As conspicuous as they are in broad daylight, the zebra's pattern must confer some kind of benefit for them to be alive in this day and age. In the natural world, conspicuousness is selected for a variety of reasons. Sexual selection has helped to shape the ornate tail of the peacock, helping males advertise themselves to choosy females. For the poison dart frog, its bright colors promise a fast and painful death to any victim unfortunate enough to lay eyes upon it. Finally, a Batesian mimic, such as the viceroy butterfly, is an animal that impersonates a noxious species as an insurance against predators. The zebra is neither poisonous nor a Batesian mimic, but, perhaps, its body patterns come to use in a similar fashion. When a zebra is in motion, its body patterns may create a kind of dynamic optical illusion. The motion dazzle hampers the lion's ability to predict the zebra's speed and direction, improving its chances of escape. The rapidly-moving stripes can also interfere with the lion's perception of spatial location. Add this to the fact that several dozen zebras will probably be bolting off in different directions during a lion attack, the lion will surely have a hard time deciding who to have for supper. At least, this is what one would think given the copious examples on camouflage as a defense mechanism. As convincing as the camouflage theory sounds, the real story behind the zebra stripe has nothing to do with hungry lions. A research team from Hungary and Sweden recently found that zebra stripes are ideal for warding off an entirely different type of predator: blood-sucking parasites. The idea is not new - a different group of researchers formulated the same hypothesis in 1981. This group, however, found solid proof for their claim by conducting experiments with light and dark stripes at a horsefly-infested farm. The horsefly is the terror of grazing animals; it delivers vicious bites and can facilitate the transfer of diseases across distant populations. According to team leader G??bor Horv??th, horseflies are attracted to horizontally polarized light because horizontally polarized water reflections help them determine where they can mate and sow their eggs. In addition, blood-sucking female tabanids have the uncanny ability to pinpoint the location of their victims using polarized light reflected from their hides. Horseflies are more attracted to dark horses than to white horses. Zebra embryos start out with dark skin, but develop their white stripes before birth. The team wanted to test whether the zebra's hide evolved to disrupt their attractive dark skins and to decrease their appeal to voracious bloodsuckers. To find their answer, the researchers trekked to a horsefly-infested horse farm near Budapest, Hungary. To test the attractiveness of various black and white striped patterns to horseflies, the team varied the width, density and angle of the stripes, as well as the direction of polarization of the light that they reflected. The insects then voted for the winning body pattern by trapping themselves in the oil and glue spread across the stripes. True to the hypothesis, the narrowest stripes attracted the fewest number of flies, indicating that zebras were selected for coat patterns that elicit the minimum possible response from dipteran parasites. As follow-up, the team tested the attractiveness of horse models with varying degrees of skin tone and stripes, predicting that the striped horse would attract an intermediate number of flies. To their surprise, the striped model was the laggard among flies. The results are pretty representative of what happens in nature: when the researchers measured stripe widths and polarization patterns in actual zebras, they observed the same trend. The consensus, then, is that zebra stripes are a wonderful adaptation: females are attracted to it, while horseflies think that it is the most horrendous body pattern to graze the African plains. Not to mention that lions are quite confounded by them. ?
(02/15/12 5:00am)
Forget about the joys of pot: driving within three hours after smoking marijuana increases your likelihood of causing a severe car crash. Thanks to observational studies done by researchers in Canada, the world's most popular illegal substance could join sleep deprivation and alcohol consumption as a widely-acknowledged contributor to driver impairment. A research team from Dalhousie University recently pioneered a meta-analysis of drivers who were killed or seriously injured in a motor vehicle accident. After reviewing a total of nine studies and 49,411 drivers, they determined that cannabis consumption nearly doubled the risk of a motor vehicle collision. Unlike previous studies, the analysis avoided mixed results by examining drivers who took cannabis prior to driving but were not under the influence of alcohol and other substances. The study obtained its results through blood samples and self-report. It focused on accidents that occurred on public roads and involved one or more moving vehicles, such as cars, vans, buses and motorcycles. While the researchers did not explore the effects of dosage on the risk and severity of collisions, the fatally-injured drivers they examined had high levels of tetrahydrocannabionol (THC), an active compound in marijuana, in their blood. This indicated that the drivers either consumed marijuana shortly before driving, or smoked a large quantity of it. Of the three studies that measured for THC levels in blood, all of them revealed a positive correlation between the risk of a car crash and elevated blood THC concentrations. However, the researchers maintain that more evidence is needed to confirm what levels of THC are needed to cause driving impairment, as well as whether cannabis contributes to minor collisions. Marijuana use has been increasing in recent years, and a greater number of drivers are driving under its influence. In 2004, a Canadian study found that four percent of adults reported driving within an hour of using pot. A roadside survey in 2007 indicated that 15 percent of Scotland drivers aged 17-39 admitted to consuming cannabis within 12 hours of driving. According to professor Wayne Hall from the University of Queensland Centre for Clinical Research, although the level of impairment from smoking pot is not as severe as alcohol intoxication, a public health response is warranted. However, Hall also claims that it is unclear whether roadside drug testing is effective. Most states and territories in Australia implement a drug-testing policy, but, as of now, no one has attempted to assess its effectiveness toward detecting drivers under the influence of cannabis. The problem arises from the fact that roadside drug testing relies on the success of random breath testing. While it is easy to measure blood alcohol levels using a breath test, it is difficult to gauge impairment using concentrations of THC in saliva. As a result, governments have often ignored the problem of defining boundaries for driving impairment by adopting a zero-tolerance policy. In addition, roadside testing has not been as widely implemented or as well-publicized as random breath testing. To supplement their findings, Hall believes that the researchers need to know the extent to which cannabis users are deterred from driving when they use cannabis. This, in turn, can help determine whether the roadside tests will successfully deter people from driving while drugged. Finally, the researchers found that drivers under the age of 35 have the greatest risk of getting involved in a vehicle collision after smoking marijuana. This reinforces Hall's belief that cannabis-detection protocols should be oriented toward younger drivers, since cannabis use is the highest in that population. The researchers hope that these findings will encourage countries to introduce better drug-testing protocols to better ensure safety on the roads. These findings support previous evidence that cannabis impairs motor skills needed for safe driving, suggesting that the general driving population will have lower incidences of severe collisions in comparison to those driving under the influence of cannabis.
(02/15/12 5:00am)
Schizophrenia severs one's connection to reality by inhibiting perception of real voices, leaving the patient at the mercy of his or her inner voice. A research team at the University of Borgen recently elucidated the neural basis of these auditory hallucinations, using their findings to develop an electronic application that may help patients to better cope with schizophrenia's symptoms. According to Dr. Kenneth Hugdahl, auditory hallucinations appear very real to the schizophrenic, as if someone were standing in close proximity and speaking to the patient. At the same time, the patient is unable to hear the voices of people who are actually present. What makes voices pathological has to do with the frequency of their recurrence. People tend to hear their names spoken in a crowd because the brain is primed to receive information that is of unique importance to the individual. Occasionally, the brain slips up and reconstructs unrelated sounds into a false perception of the person's name. For the schizophrenic, however, the inner voices can be a recurring and relentless plague. One of the most common symptoms of schizophrenia, auditory hallucinations, go beyond mistakenly hearing one's name in a crowd. The hallucinations can manifest in a variety of ways, from a running commentary of a person's thoughts to a voice ordering him or her to commit suicide. The powerful emotions experienced by some patients may increase the frequency of these verbal messages, leading to feelings of distress and helplessness. Dr. Hugdahl and colleagues have attempted to better understand these hallucinations using a variety of neuroimaging techniques, including functional magnetic resonance imaging technology (fMRI). They found that in healthy patients, the perception of speech was accompanied by the spontaneous activation of neurons in the upper region of the left temporal lobe. From these findings, Dr. Hugdahl theorized that neural activity in this area would be somewhat increased, or even doubled, in schizophrenic patients. Instead, the team found that activity in the upper left temporal lobe ceased altogether in the presence of an inner voice. Dr. Hugdahl and his colleagues, Kristina Kompus and Ren?? Westerhausen, followed up with a meta-analysis of 23 studies. The researchers looked at spontaneous inner-voice triggered neural activation in patients with schizophrenia or the stimulatory reaction prompted by actual sounds in healthy as well as schizophrenic subjects. Through their examination, the researchers discovered that most papers reported either the perception of inner voices was accompanied by a spontaneous activation of neurons, or the patients' perception of actual voices was suppressed when inner voices were simultaneously present. Hugdahl and his colleagues are the first to see the connection between these seemingly separate phenomena. Further analysis revealed that one phenomenon was caused by the other; when neurons are activated by inner voices, the perception of outside speech is inhibited. This relationship exists because the preoccupied neurons are unable to properly process speech coming from the external environment. The findings may explain why schizophrenics lose touch with reality and close themselves off when experiencing hallucinations. As further support for why schizophrenic patients become consumed by their inner voices, Hugdahl and colleagues found that the frontal lobe did not function normally in patients with schizophrenia. The result is poorer impulse control and an inability to block out hallucinations. While everyone hears inner voices or melodies from time to time, non-schizophrenic patients are better at tuning out these internal voices. To help patients learn to suppress their inner voices, Dr. Hugdahl's team developed an application for mobile phones and other simple electronic devices. The application broadcasts simple speech sounds via headphones and plays different sounds in each ear. The patient must learn to hear the sound in one ear while blocking out the sound in the other. So far, the application has been tested on two patients with schizophrenia. The results are promising; while the voices are still there, the patients report feeling that they have more control over the voices. The patients are able to actively shift their focuses from the inner voices to external sounds, a possible breakthrough in the treatment of schizophrenia.
(02/08/12 5:00am)
A team of ecologists recently captured the vocalizations of deep-sea fish in a recording that includes familiar sounds, such as dolphin and humpback whale calls. These findings support long-standing hypotheses about fish communication in the under-explored mesopelagic zone.
(02/08/12 5:00am)
Photosynthesis incorporated into solar energy system
(02/01/12 5:00am)
A group of five Bottlenose dolphins at the Planète Sauvage aquarium in Port-Saint-Père, France, was found to mimic whale sounds at night. These dolphins were exposed to whale songs through the soundtrack from their daily shows, which included bird cries and other marine sounds.
(12/01/11 5:00am)
The ocean is a dangerous place, especially if you are a soft-bodied squid or octopus. Many predators in the bathypelagic zone, a dimly-lit section of the ocean that extends from 700 to 1000 meters below the surface, spot the silhouettes of their prey against the lighter background of the surface layers. Others, like the well-known anglerfish, use the searchlights on their heads.
(11/17/11 5:00am)
A Scripps research team led by chemist Phil Baran recently synthesized the largest amount of pure taxadiene to date. Taxanes, a family of compounds that includes Taxol, one of the most important cancer drugs discovered, have been difficult to isolate in the past due to their complexity. These findings suggest the possibility of researching previously unavailable potential drugs.
(10/26/11 5:00am)
The legendary kraken, a colossal octopus that allegedly caused whales and ships to flee the coasts of Norway and Iceland, may in fact be real. The kraken is believed to have been almost 100 feet long, or twice the size of the colossal squid, and its fossil shows vertebrae that resemble the suckers of a cephalopod tentacle.
(10/19/11 5:00am)
Recent research shows that Trinidadian guppies display female-against-female aggression in the presence of a harassing male.
(10/12/11 5:00am)
Medical professionals are not as unbiased as many people like to think. According to a recent study, people tend to underestimate pain intensity and are less sympathetic to a patient's pain when the patient is not well-liked. The study, published in the October 2011 issue of Pain, has alarming implications for patient care.
(09/28/11 5:00am)
Researchers at the Hopkins School of Medicine recently described the fossil of an armored dinosaur hatchling. Discovered in 1997 by amateur fossil hunter Ray Stanford, the dinosaur is the youngest nodosaur ever discovered and the first hatchling of any dinosaur species discovered in the eastern United States.
(09/21/11 5:00am)
A study found that the amydgala, a brain center involved in emotional learning and memory, responds preferentially and more rapidly to images of animals. These findings indicate that the amygdala is hardwired to detect nonhuman animals and may explain why some people are drawn to furry animals while others develop phobias of spiders.
(09/14/11 5:00am)
A recent study found that mice living in socially enriching environments converted a greater portion of their energy-storing white fat to energy-burning brown fat, losing weight despite their increased caloric intake. These findings reinforce how social and physical environments can impact animal metabolisms.
(09/07/11 5:00am)
An international research team recently found a deep-ocean current off the coast of Iceland. The discovery of the current, also known as the North Icelandic Jet (NIJ), may change model predictions for oceanic responses to climate change.
(05/05/11 8:43pm)
Researchers recently found evidence that the placenta, the organ that connects the fetus to the uterine wall of its mother, contributes to fetal brain development during pregnancy. Experiments in mice showed that the placenta functions as a source of serotonin during a key period, contributing to the wiring of brain circuits. These findings could potentially explain how brain disorders such as schizophrenia develop.
(04/28/11 6:48pm)
A team of Hopkins scientists recently developed a method to safely turn blood cells into functional cardiac myocytes. The researchers claim that this method produces virus-free heart cells that beat with nearly a 100 percent efficiency.
(04/21/11 5:55pm)
Heart disease and afflictions such as obesity are often viewed as a product of modern culture. People today are thought to consume significantly more calories and animal fat than their ancestors, turning our fat-storing adaptation into a contributing factor for obesity.