Tag Later - Blog Posts
Herd immunity is the idea that if enough people get immunized against a disease, they’ll create protection for even those who aren’t vaccinated. This is important to protect those who can’t get vaccinated, like immunocompromised children.
You can see in the image how low levels of vaccination lead to everyone getting infected. Medium levels slow down the progression of the illness, but they don’t offer robust protection to the unvaccinated. But once you read a high enough level of vaccination, the disease gets effectively road-blocked. It can’t spread fast enough because it encounters too many vaccinated individuals, and so the majority of the population (even the unvaccinated people) are protected.
Find out more here.
“Surface tension dictates the spherical cap shape of small sessile drops, whereas gravity flattens larger drops into millimeter-thick flat puddles. In contrast with drops, soap bubbles remain spherical at much larger sizes. However, we demonstrate experimentally and theoretically that meter-sized bubbles also flatten under their weight, and we compute their shapes. We find that mechanics does not impose a maximum height for large soap bubbles, but, in practice, the physicochemical properties of surfactants limit the access to this self-similar regime where the height grows as the radius to the power 2/3. An exact analogy shows that the shape of giant soap bubbles is nevertheless realized by large inflatable structures.” Via.
The Brain Can Reveal Drinking Status Even After Death
Scientists who use postmortem brain tissue to study alcohol’s effects on brain structure and function will find this research interesting. Phosphatidylethanol (PEth) is an alcohol metabolite and its concentration in whole blood samples is a biomarker of drinking habits. For this study, scientists examined PEth levels in postmortem brains of individuals known to have had alcohol use disorders (AUDs).
Researchers divided 30 postmortem brains into three groups: 10 with AUDs that had positive serum alcohol levels present at the time of autopsy; 10 with AUDs that did not show positive serum alcohol levels at the time of autopsy; and 10 normal brains. PEth levels were measured in the cerebellum and orbital frontal cortex (OFC) regions.
Results showed that PEth was present in the cerebellum and OFC of all brains in all three groups of subjects, including the controls. The AUD group with detectable serum alcohol levels at the time of autopsy had much higher levels of PEth in both brain areas than either the control group or the AUD group whose subjects did not have detectable serum ethanol at autopsy. Thus, the ability to measure PEth levels in postmortem human brains can be helpful in classifying drinking status in individuals with AUDs at the time of death.
Scalp is the soft tissue layer covering the bony vault over the brain. It is usually described as having five layers: S: The skin on the head from which head hair grows. It contains numerous sabaeceous glands and hair follicles C: Connective tissue. A thin layer of fat and fibrous tissue lies beneath the skin. A: The aponeurosis called epicranial aponeurosis (or galea aponeurotica) is the next layer. It is a tough layer of dense fibrous tissue which runs from the frontalis muscle anteriorly to the occipitalis posteriorly. L: The loose areolar connective tissue layer provides an easy plane of separation between the upper three layers and the pericranium. P: The pericranium is the periosteum of the skull bones and provides nutrition to the bone and the capacity for repair.
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English-speaking parents tend to use vague, one-size-fits-all verbs as they emphasize nouns: cars, trucks, buses, bicycles and scooters all simply “go.” Mandarin speakers do the opposite: they use catchall nouns such as “vehicle” but describe action—driving, riding, sitting on, pushing—with very specific verbs. “As a native English speaker, my first instinct when a baby points is to label,” Tardif says. Her babysitter, on the other hand, was a native Mandarin speaker, whose instinct was to name the action she thought the child was trying to achieve.
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What does it take to teach a bee to use tools? A little time, a good teacher and an enticing incentive. Read more here: http://to.pbs.org/2mpRUAz
Credit: O.J. Loukola et al., Science (2017)
It’s way too late for this, but it’s important to note that NASA didn’t discover the new earth-like planets. It was a group of astronomers lead by a dude name Michaël Gillon from the University of Liège in Belgium. Giving NASA credit for this gives the United States credit for something they didn’t do, and we already have a problem with making things about ourselves so. just like…be mindful. I’d be pissed if I discovered a small solar system and credit was wrongfully given to someone else.
Machine Learning: An In-Depth, Non-Technical Guide
A good introductory text in five parts:
Overview, goals, learning types, and algorithms
Data selection, preparation, and modeling
Model evaluation, validation, complexity, and improvement
Model performance and error analysis
Unsupervised learning, related fields, and machine learning in practice
By Alex Castrounis - {InnoArchiTech}
Just Made a Bad Decision?
Most people experience anxiety in their lives. For some, it is just a bad, passing feeling, but, for many, anxiety rules their day-to-day lives, even to the point of taking over the decisions they make.
Scientists at the University of Pittsburgh have discovered a mechanism for how anxiety may disrupt decision making. In a study published in The Journal of Neuroscience, they report that anxiety disengages a region of the brain called the prefrontal cortex (PFC), which is critical for flexible decision making. By monitoring the activity of neurons in the PFC while anxious rats had to make decisions about how to get a reward, the scientists made two observations. First, anxiety leads to bad decisions when there are conflicting distractors present. Second, bad decisions under anxiety involve numbing of PFC neurons.
The data indicates that anxiety has an exquisitely selective effect on neuronal activity that supports decision making, says Bita Moghaddam, the lead author of the study and a professor in the Department of Neuroscience within the Kenneth P. Dietrich School of Arts and Sciences. Up to now, scientists have mostly studied anxiety in animal models in the context of fear and measured how brain cells react to a threatening situation. But human anxiety is devastating, not merely because of how the person feels, but also because it can interfere with nearly all aspects of daily life including decision making, Moghaddam says.
Pitt researchers studied this aspect of anxiety by monitoring the activity of a large number of neurons as rats made decisions about which choice was most optimal for receiving a reward. They compared behavior and neuronal activity in two groups: one group that had a placebo injection and another that got a low dose of an anxiety-inducing drug.
As with many people who suffer from anxiety but go through day-to-day life and make decisions, the anxious rats completed the decision-making task and, actually, did not do too badly. But they made far more mistakes when the correct choice involved ignoring distracting information. “A brain locus of vulnerability for these anxiety-induced mistakes was a group of cells in the PFC that specifically coded for choice. Anxiety weakened the coding power of these neurons.
“We have had a simplistic approach to studying and treating anxiety. We have equated it with fear and have mostly assumed that it over-engages entire brain circuits. But this study shows that anxiety disengages brain cells in a highly specialized manner.”
Perhaps, down the line, this better understanding of the brain mechanics behind anxiety and decision making, she says, could lead to better treatment of anxiety in people and, subsequently, better outcomes in the treatment of psychiatric disorders.
Back in the 1960s, the U.S. started vaccinating kids for measles. As expected, children stopped getting measles.
But something else happened.
Childhood deaths from all infectious diseases plummeted. Even deaths from diseases like pneumonia and diarrhea were cut by half.
“So it’s really been a mystery — why do children stop dying at such high rates from all these different infections following introduction of the measles vaccine,” says Michael Mina, a postdoc in biology at Princeton University and a medical student at Emory University.
Scientists Crack A 50-Year-Old Mystery About The Measles Vaccine Photo credit: Photofusion/UIG via Getty Images
A guy asks an engineer “hey what 2 + 2?”
Engineer responds “4. No wait make 5 just to be on the safe side.”
It often seems so quiet after a snowfall because the fresh powder absorbs sound waves. As the snow melts and freezes, it then creates a reflective surface that allows sound to travel farther than normal. Source
Now we know the (proposed) names of the four new elements, here’s an updated graphic with more information on each! High-res image/PDF: http://wp.me/p4aPLT-1Eg
Absence of Serotonin Alters Development and Function of Brain Circuits
Researchers at Case Western Reserve University School of Medicine have created the first complete model to describe the role that serotonin plays in brain development and structure. Serotonin, also called 5-hydroxytryptamine [5-HT], is an important neuromodulator of brain development and the structure and function of neuronal (nerve cell) circuits. The results were published in the current issue of The Journal of Neurophysiology online.
“Our goal in the project was to close the gap in knowledge that exists on role of serotonin in the brain cortex, particularly as it concerns brain circuitry, its electrical activity and function,” said Roberto Fernández Galán, PhD, Assistant Professor in the Department of Neurosciences at Case Western Reserve University School of Medicine. “For the first time, we can provide a complete description of an animal model from genes to behavior—including at the level of neuronal network activity, which has been ignored in most studies to date.”
Dr. Galán and his team used high-density multi-electrode arrays in a mouse model of serotonin deficiency to record and analyze neuronal activity. The study supports the importance of the serotonin which is specified and maintained by a specific gene, the Pet-1 gene – for normal functioning of the neurons, synapses and networks in the cortex, as well as proper development of brain circuitry. Serotonin abnormalities have been linked to autism and epilepsy, depression and anxiety. By more fully elucidating the role of serotonin in the brain, this study may contribute to a better understanding of the development or treatment of these conditions.
“By looking at the circuit level of the brain, we now have new insight into how the brain becomes wired and sensitive to changing serotonin levels.” added Dr. Galán.
Newly discovered windows of brain plasticity may help with treatment of stress-related disorders
Chronic stress can lead to changes in neural circuitry that leave the brain trapped in states of anxiety and depression. But even under repeated stress, brief opportunities for recovery can open up, according to new research at The Rockefeller University.
(Image caption: Routine versus disruptive: A familiar stressor (left) did not increase NMDA receptors (dark spots), a booster of potentially harmful glutamate signaling, in the brains of mice. However, when subjected to an unfamiliar stress (right), mice expressed more NMDA receptors)
“Even after a long period of chronic stress, the brain retains the ability to change and adapt. In experiments with mice, we discovered the mechanism that alters expression of key glutamate-controlling genes to make windows of stress-related neuroplasticity—and potential recovery—possible,” says senior author Bruce McEwen, Alfred E. Mirsky Professor, and head of the Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology. Glutamate is a chemical signal implicated in stress-related disorders, including depression.
“This sensitive window could provide an opportunity for treatment, when the brain is most responsive to efforts to restore neural circuitry in the affected areas,” he adds.
The team, including McEwen and first author Carla Nasca, wanted to know how a history of stress could alter the brain’s response to further stress. To find out, they accustomed mice to a daily experience they dislike, confinement in a small space for a short period. On the 22nd day, they introduced some of those mice to a new stressor; others received the now-familiar confinement.
Then, the researchers tested both groups for anxiety- or depression-like behaviors. A telling split emerged: Mice tested shortly after the receiving the familiar stressor showed fewer of those behaviors; meanwhile those given the unfamiliar stressor, displayed more. The difference was transitory, however; by 24 hours after the final stressor, the behavioral improvements seen in half of the mice had disappeared.
Molecular analyses revealed a parallel fluctuation in a part of the hippocampus, a brain region involved in the stress response. A key molecule, mGlu2, which tamps down the release of the neurotransmitter glutamate, increased temporarily in mice subjected to the familiar confinement stress. Meanwhile, a molecular glutamate booster, NMDA, increased in other mice that experienced the unfamiliar stressor. In stress-related disorders, excessive glutamate causes harmful structural changes in the brain.
The researchers also identified the molecule regulating the regulator, an enzyme called P300. By adding chemical groups to proteins known as histones, which give support and structure to DNA, P300 increases expression of mGlu2, they found.
In other experiments, they looked at mice genetically engineered to carry a genetic variant associated with development of depression and other stress-related disorders in humans, and present in 33 percent of the population.
“Here again, in experiments relevant to humans, we saw the same window of plasticity, with the same up-then-down fluctuations in mGlu2 and P300 in the hippocampus,” Nasca says. “This result suggests we can take advantage of these windows of plasticity through treatments, including the next generation of drugs, such as acetyl carnitine, that target mGlu2—not to ‘roll back the clock’ but rather to change the trajectory of such brain plasticity toward more positive directions.”
why do we have butt cheeks i dont understand why did we evolve this way
what use do butt cheeks have
Scientists have discovered the world’s oldest known water in an ancient pool in Canada that’s at least 2 billion years old.
Back in 2013 they found water dating back about 1.5 billion years at the Kidd Mine in Ontario, but searching deeper at the site revealed an even older source buried underground.
The initial discovery of the ancient liquid in 2013 came at a depth of around 2.4 kilometres (1.5 miles) in an underground tunnel in the mine. But the extreme depth of the mine – which at 3.1 kilometres (1.9 miles) is the deepest base metal mine in the world – gave researchers the opportunity to keep digging.
“[The 2013 find] really pushed back our understanding of how old flowing water could be and so it really drove us to explore further,” geochemist Barbara Sherwood Lollar from the University of Toronto told Rebecca Morelle at the BBC.
“And we took advantage of the fact that the mine is continuing to explore deeper and deeper into the earth.”
The new source was found at about 3 kilometres (1.9 miles) down, and according to Sherwood Lollar, there’s a lot more of it than you might expect.
Continue Reading.
From vision to hand action
Our hands are highly developed grasping organs that are in continuous use. Long before we stir our first cup of coffee in the morning, our hands have executed a multitude of grasps. Directing a pen between our thumb and index finger over a piece of paper with absolute precision appears as easy as catching a ball or operating a doorknob. The neuroscientists Stefan Schaffelhofer and Hansjörg Scherberger of the German Primate Center (DPZ) have studied how the brain controls the different grasping movements. In their research with rhesus macaques, it was found that the three brain areas AIP, F5 and M1 that are responsible for planning and executing hand movements, perform different tasks within their neural network. The AIP area is mainly responsible for processing visual features of objects, such as their size and shape. This optical information is translated into motor commands in the F5 area. The M1 area is ultimately responsible for turning this motor commands into actions. The results of the study contribute to the development of neuroprosthetics that should help paralyzed patients to regain their hand functions (eLife, 2016).
The three brain areas AIP, F5 and M1 lay in the cerebral cortex and form a neural network responsible for translating visual properties of an object into a corresponding hand movement. Until now, the details of how this “visuomotor transformation” are performed have been unclear. During the course of his PhD thesis at the German Primate Center, neuroscientist Stefan Schaffelhofer intensively studied the neural mechanisms that control grasping movements. “We wanted to find out how and where visual information about grasped objects, for example their shape or size, and motor characteristics of the hand, like the strength and type of a grip, are processed in the different grasp-related areas of the brain”, says Schaffelhofer.
For this, two rhesus macaques were trained to repeatedly grasp 50 different objects. At the same time, the activity of hundreds of nerve cells was measured with so-called microelectrode arrays. In order to compare the applied grip types with the neural signals, the monkeys wore an electromagnetic data glove that recorded all the finger and hand movements. The experimental setup was designed to individually observe the phases of the visuomotor transformation in the brain, namely the processing of visual object properties, the motion planning and execution. For this, the scientists developed a delayed grasping task. In order for the monkey to see the object, it was briefly lit before the start of the grasping movement. The subsequent movement took place in the dark with a short delay. In this way, visual and motor signals of neurons could be examined separately.
The results show that the AIP area is primarily responsible for the processing of visual object features. “The neurons mainly respond to the three-dimensional shape of different objects”, says Stefan Schaffelhofer. “Due to the different activity of the neurons, we could precisely distinguish as to whether the monkeys had seen a sphere, cube or cylinder. Even abstract object shapes could be differentiated based on the observed cell activity.”
In contrast to AIP, area F5 and M1 did not represent object geometries, but the corresponding hand configurations used to grasp the objects. The information of F5 and M1 neurons indicated a strong resemblance to the hand movements recorded with the data glove. “In our study we were able to show where and how visual properties of objects are converted into corresponding movement commands”, says Stefan Schaffelhofer. “In this process, the F5 area plays a central role in visuomotor transformation. Its neurons receive direct visual object information from AIP and can translate the signals into motor plans that are then executed in M1. Thus, area F5 has contact to both, the visual and motor part of the brain.”
Knowledge of how to control grasp movements is essential for the development of neuronal hand prosthetics. “In paraplegic patients, the connection between the brain and limbs is no longer functional. Neural interfaces can replace this functionality”, says Hansjörg Scherberger, head of the Neurobiology Laboratory at the DPZ. “They can read the motor signals in the brain and use them for prosthetic control. In order to program these interfaces properly, it is crucial to know how and where our brain controls the grasping movements”. The findings of this study will facilitate to new neuroprosthetic applications that can selectively process the areas’ individual information in order to improve their usability and accuracy.