Using modern statistical tools, a new study led by the University of Washington and the United Nations finds that world population is likely to keep growing throughout the 21st century. The number of people on Earth is likely to reach 11 billion by 2100, the study concludes, about 2 billion higher than some previous estimates.
The paper published online Sept. 18 in the journal Science includes the most up-to-date estimates for future world population, as well as a new method for creating such estimates.
Human sensitivity to wetness plays a role in many aspects of daily life. Whether feeling humidity, sweat or a damp towel, we often encounter stimuli that feel wet. Though it seems simple, feeling that something is wet is quite a feat because our skin does not have receptors that sense wetness. The concept of wetness, in fact, may be more of a “perceptual illusion” that our brain evokes based on our prior experiences with stimuli that we have learned are wet.
So how would a person know if he has sat on a wet seat or walked through a puddle? Researchers at Loughborough University and Oxylane Research proposed that wetness perception is intertwined with our ability to sense cold temperature and tactile sensations such as pressure and texture. They also observed the role of A-nerve fibers—sensory nerves that carry temperature and tactile information from the skin to the brain—and the effect of reduced nerve activity on wetness perception. Lastly, they hypothesized that because hairy skin is more sensitive to thermal stimuli, it would be more perceptive to wetness than glabrous skin (e.g., palms of the hands, soles of the feet), which is more sensitive to tactile stimuli.
Davide Filingeri et al. exposed 13 healthy male college students to warm, neutral and cold wet stimuli. They tested sites on the subjects’ forearms (hairy skin) and fingertips (glabrous skin). The researchers also performed the wet stimulus test with and without a nerve block. The nerve block was achieved by using an inflatable compression (blood pressure) cuff to attain enough pressure to dampen A-nerve sensitivity.
They found that wet perception increased as temperature decreased, meaning subjects were much more likely to sense cold wet stimuli than warm or neutral wet stimuli. The research team also found that the subjects were less sensitive to wetness when the A-nerve activity was blocked and that hairy skin is more sensitive to wetness than glabrous skin. These results contribute to the understanding of how humans interpret wetness and present a new model for how the brain processes this sensation.
“Based on a concept of perceptual learning and Bayesian perceptual inference, we developed the first neurophysiological model of cutaneous wetness sensitivity centered on the multisensory integration of cold-sensitive and mechanosensitive skin afferents,” the research team wrote. “Our results provide evidence for the existence of a specific information processing model that underpins the neural representation of a typical wet stimulus.”
The article “Why wet feels wet? A neurophysiological model of human cutaneous wetness sensitivity” is published in the Journal of Neurophysiology.
The more curious we are about a topic, the easier it is to learn information about that topic. New research publishing online October 2 in the Cell Press journal Neuron provides insights into what happens in our brains when curiosity is piqued. The findings could help scientists find ways to enhance overall learning and memory in both healthy individuals and those with neurological conditions.
"Our findings potentially have far-reaching implications for the public because they reveal insights into how a form of intrinsic motivation—curiosity—affects memory. These findings suggest ways to enhance learning in the classroom and other settings," says lead author Dr. Matthias Gruber, of University of California at Davis.
For the study, participants rated their curiosity to learn the answers to a series of trivia questions. When they were later presented with a selected trivia question, there was a 14 second delay before the answer was provided, during which time the participants were shown a picture of a neutral, unrelated face. Afterwards, participants performed a surprise recognition memory test for the faces that were presented, followed by a memory test for the answers to the trivia questions. During certain parts of the study, participants had their brains scanned via functional magnetic resonance imaging.
The study revealed three major findings. First, as expected, when people were highly curious to find out the answer to a question, they were better at learning that information. More surprising, however, was that once their curiosity was aroused, they showed better learning of entirely unrelated information (face recognition) that they encountered but were not necessarily curious about. People were also better able to retain the information learned during a curious state across a 24-hour delay. “Curiosity may put the brain in a state that allows it to learn and retain any kind of information, like a vortex that sucks in what you are motivated to learn, and also everything around it,” explains Dr. Gruber.
Second, the investigators found that when curiosity is stimulated, there is increased activity in the brain circuit related to reward. “We showed that intrinsic motivation actually recruits the very same brain areas that are heavily involved in tangible, extrinsic motivation,” says Dr. Gruber. This reward circuit relies on dopamine, a chemical messenger that relays messages between neurons.
Third, the team discovered that when curiosity motivated learning, there was increased activity in the hippocampus, a brain region that is important for forming new memories, as well as increased interactions between the hippocampus and the reward circuit. “So curiosity recruits the reward system, and interactions between the reward system and the hippocampus seem to put the brain in a state in which you are more likely to learn and retain information, even if that information is not of particular interest or importance,” explains principal investigator Dr. Charan Ranganath, also of UC Davis.
The findings could have implications for medicine and beyond. For example, the brain circuits that rely on dopamine tend to decline in function as people get older, or sooner in people with neurological conditions. Understanding the relationship between motivation and memory could therefore stimulate new efforts to improve memory in the healthy elderly and to develop new approaches for treating patients with disorders that affect memory. And in the classroom or workplace, learning what might be considered boring material could be enhanced if teachers or managers are able to harness the power of students’ and workers’ curiosity about something they are naturally motivated to learn.
For the first time flowering plants have been successfully engineered to fix carbon like the blue-green algae do – this can potentially increase photosynthesis and yields in crop plants.
Plants, algae and some bacteria capture light energy from the sun and transform it into chemical energy by the process named photosynthesis. Blue-green algae (cyanobacteria) have a more efficient mechanism in carrying out photosynthesis than plants. For a long time now, it has been suggested that if plants could carry out photosynthesis with a similar mechanism to that of the blue-green algae, plant productivity and hence crop yields could improve.
Rothamsted Research scientists strategically funded by the BBSRC and in collaboration with colleagues at Cornell University funded by the U.S. National Science Foundation have used genetic engineering of tobacco plants - a tobacco plant can been seen above - to demonstrate for the first time that flowering plants can carry out photosynthesis utilizing a faster bacterial Rubisco enzyme rather than their own slower Rubisco enzyme. These findings represent a milestone toward the goal of improving the photosynthetic rate in crop plants.
Copyright: Rothamsted Research
Mom’s Diet Impacts Child’s DNA
A mother’s diet before conception can permanently affect how her child’s genes function, according to a study published in Nature Communications. The first such evidence of the effect in humans opens up the possibility that a mother’s diet before pregnancy could permanently affect many aspects of her children’s lifelong health.
Researchers from the MRC International Nutrition Group, based at the London School of Hygiene & Tropical Medicine and MRC Unit, The Gambia, utilized a unique, “experiment of nature,” in rural Gambia, where the population’s dependence on own grown foods and a markedly seasonal climate impose a large difference in people’s dietary patterns between rainy and dry seasons.
Read more: http://www.laboratoryequipment.com/news/2014/04/moms-diet-impacts-childs-dna
Kinesin is a protein that moves things around the cell. That filament is a protein strand that gives the cell structure. That vesicle is a big blob full of cellular product that the cell wants to transport somewhere else. It is driven by ATP hydrolysis. (Source) (Video)
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