13 fevereiro 2015

Aurora on Ice



Not from a snowglobe, this expansive fisheye view of ice and sky was captured on February 1, from Jökulsárlón Beach, southeast Iceland, planet Earth. Chunks of glacial ice on the black sand beach glisten in the light of a nearly full moon surrounded by a shining halo. The 22 degree lunar halo itself is created by ice crystals in high, thin clouds refracting the moonlight. Despite the bright moonlight, curtains of aurora still dance through the surreal scene. In early February, their activity was triggered by Earth's restless magnetosphere and the energetic wind from a coronal hole near the Sun's south pole. Bright Jupiter, also near opposition, is visible at the left, beyond the icy lunar halo.



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New fluorescent protein permanently marks neurons that fire A...





New fluorescent protein permanently marks neurons that fire


A new tool developed at the Howard Hughes Medical Institute’s Janelia Research Campus lets scientists shine a light on an animal’s brain to permanently mark neurons that are active at a particular time. The tool — a fluorescent protein called CaMPARI — converts from green to red when calcium floods a nerve cell after the cell fires. The permanent mark frees scientists from the need to focus a microscope on the right cells at the right time to observe neuronal activity.


Calcium-sensitive fluorescent molecules called GCaMP emit a fluorescent signal that indicates neural activity, and are useful for following the dynamics of neural networks. But their signal is temporary, and if researchers miss it because the microscope is not focused on the right spot in the brain, the information is lost. With CaMPARI, researchers can visualize neural activity beyond a microscope’s limited field of view, capturing a snapshot of neural activity across wide swaths of brain tissue. The new tool also enables scientists to visualize neural activity during more complicated behaviors than previous calcium indicators, because in many cases it can be used while animals move freely, rather than being confined to a dish or embedded in agar.


“The most enabling thing about this technology may be that you don’t have to have your organism under a microscope during your experiment,” says Loren Looger, a group leader and protein chemist at Janelia who engineers tools to study the brain. “So we can now visualize neural activity in fly larvae crawling on a plate or fish swimming in a dish.”


Looger, Eric Schreiter, and their colleagues report on CaMPARI and its ability to label active neural circuits in fruit flies, zebrafish, and mice in the February 13, 2015, issue of the journal Science.


Schreiter, a senior scientist in Looger’s lab, led the development of CaMPARI, working as part of Janelia’s Genetically-Encoded Neuronal Indicator and Effector (GENIE) project team. GENIE is an interdisciplinary team dedicated to engineering fluorescent sensors that facilitate the imaging of neuronal activity in living organisms. Project teams are like small start-up companies within Janelia and were created to tackle biological problems that require collaboration across multiple labs.


To make CaMPARI, the team started with a fluorescent protein called Eos. Eos emits a green fluorescence until it is exposed to violet light, which permanently alters the protein so that it fluoresces in red. “That was the perfect starting place,” says Schreiter. “That conversion from green to red gives us a permanent signal. So we just needed a way to couple that conversion to the activity that’s going on in the cell.” To do that, the scientists incorporated a calcium-sensitive protein known as calmodulin, which makes the color change dependent on the burst of calcium that accompanies neural activity. It’s the same domain that scientists added to fluorescent proteins to make calcium-responsive GCaMP sensors.


To find a useful protein that switches the color of its fluorescence only in the presence of both calcium and an activating violet light, the researchers made and screened tens of thousands of subtly different proteins. “When we finally got one that photoconverted more with calcium than without it, we knew we had a tool. We just needed to make it better to get it to the point where another neuroscientist could sit down and use it,” says first author Ben Fosque, a graduate student in the biochemistry and molecular biophysics program at the University of Chicago.


The team spent more than a year tweaking their protein – making it brighter and more responsive to calcium and ensuring that it would work in cells and then in living mice, fruit flies, and zebrafish. In the end, they had a tool that they named CaMPARI, which stands for calcium-modulated photoactivatable ratiometric integrator.


The need to use violet light in converting the protein’s fluorescence gives experimenters control over the time period during which neural activity is tracked. “Ideally, we can flip the light switch on while an animal is doing the behavior that we care about, then flip the switch off as soon as the animal stops doing the behavior,” Schreiter explains. “Then we’re capturing a snapshot of only the activity that occurs while the animal is doing that behavior.”


The scientists conducted a series of experiments to demonstrate CaMPARI’s effectiveness. In one set of experiments, they captured a snapshot of neuronal activity over the entire brain volume of a zebrafish during a ten-second period as it swam in a dish. Following the experiment, CaMPARI was red in motor neurons known to be involved in swimming, as well as other expected sets of neurons–consistent with observations made by other scientists during electrophysiology experiments. The activation patterns changed significantly when the researchers altered the temperature or turbulence of the water.


In fruit flies, the team used CaMPARI to identify neurons that were activated in response to specific odors. Here too, the observations were as expected based on previous experiments: CaMPARI indicated that different odors activated distinct sets of neurons in the flies’ antennal lobes. In a subsequent set of experiments, the researchers experimentally activated the neurons that directly responded to the odors, then looked for neurons elsewhere in the brain that subsequently turned red. Those experiments revealed neurons that Schreiter says may be secondary, tertiary, or even quaternary components to the olfactory circuits. Tracing a circuit from one neuron to the next is difficult under a microscope, the scientists say, because cell projections and their connections to other cells generally extend beyond the instrument’s field of view.


With ongoing development, the scientists expect future versions of CaMPARI will be more sensitive and reliable than the current tool. But Looger says it’s important to get CaMPARI into the hands of neuroscientists right away. “The idea is probably more powerful than the tool, as it stands right now,” he says. “We will definitely benefit from a couple hundred–hopefully a thousand–labs taking CaMPARI and seeing what they can do with it.”


To that end, the team has made the genetic plasmid encoding CaMPARI available through the plasmid repository Addgene; transgenic flies expressing CaMPARI are available through the Bloomington Drosophila Stock Center; and Janelia group leader Misha Ahrens is distributing CaMPARI-expressing zebrafish to researchers. Tools for introducing CaMPARI into mouse cells should be available soon, the scientists say.


CaMPARI fluorescence in a larval zebrafish brain showing active neurons (magenta) that were marked while the fish was swimming freely. Credit: Looger Lab, HHMI/Janelia


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ageofdestruction:200 block emmet street, newark, new...





ageofdestruction:



200 block emmet street, newark, new jersey.


google street view study.


animation: ageofdestruction.



the promise fulfilled and the promise broken


age
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Here are some worthy causes you can support instead of seeing Fifty Shades of Grey:

gaywrites:The Asian & Pacific Islander Institute on Domestic ViolenceBattered Women’s Justice...
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can you give more examples on how 50 shades of grey is about control and abuse?

If you still need examples that depict how 50 Shades of Grey is about Christian Grey’s dominance and...
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The Science of Love

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Growing Deltas in Atchafalaya Bay



The delta plain of the Mississippi River is disappearing. The lobe-shaped arc of coastal land from the Chandeleur Islands in eastern Louisiana to the Sabine River loses a football field’s worth of land every hour. Put another way, the delta has shrunk by nearly 5,000 square kilometers (2,000 square miles) over the past 80 years. That’s as if most of Delaware had sunk into the sea. Though land losses are widely distributed across the 300 kilometer (200 mile) wide coastal plain of Louisiana, Atchafalaya Bay stands as a notable exception. In a swampy area south of Morgan City, new land is forming at the mouths of the Wax Lake Outlet and the Atchafalaya River. Wax Lake Outlet is an artificial channel that diverts some of the river’s flow into the bay about 16 kilometers (10 miles) west of where the main river empties. Both deltas are being built by sediment carried by the Atchafalaya River. The Atchafalaya is a distributary of the Mississippi River, connecting to the “Big Muddy” in south central Louisiana near Simmesport. Studies of the geologic history of the meandering Mississippi have shown that—if left to nature—most of the river’s water would eventually flow down the Atchafalaya. But the Old River Control Structure, built in the 1960s by the U.S. Army Corps of Engineers, ensures that only 30 percent of the Mississippi flows into the Atchafalaya River, while the rest of the keeps moving toward Baton Rouge and New Orleans. More information. Image Credit: NASA/Earth Observatory



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FREE on Kindle (Feb 13/14) Perception: An Introduction To The...





FREE on Kindle (Feb 13/14) Perception: An Introduction To The Gestalt Theory.



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If you live outside the USA/UK just type the title or B00LLHOXY0 into the Amazon search box.



A classic in the history of psychology Perception: An Introduction To The Gestalt Theory was the first paper Kurt Koffka wrote in English. It was also the first article on Gestalt psychology to be published in an American journal when it appeared in the Psychological Bulletin in October 1922.



This landmark publication has been reproduced in kindle format as part of an initiative by the website http://ift.tt/1eWNk1f to make important, insightful and engaging psychology publications widely available.


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The Spectacular Success of the Measles Vaccine

themendozaline:


image Click here to enlarge this image.

By David Mendoza - Wednesday, June 18, 2014


Recently, there has been increased attention paid to the resurgence of measles in the United States. But despite this uptick, it’s important to remember how effective the measles vaccine has been at reducing the prevalence of the disease. Since 1963, when John F. Enders helped develop the first vaccine against the measles, the number of cases of this respiratory disease has declined considerably. By the end the 1960s, according to Samuel L. Katz, Chairman Emeritus of Pediatrics at Duke University, “annual measles cases had been reduced by more than 90%.” Immediately before then, approximately 400 people died and more than 3 million people were infected by measles every year.


The chart at the top of the page displays the remarkable reduction in the measles incidence rate per 100,000 people in the United States. The incidence rate is defined by the CDC as the number of new cases of a disease over a given period that is then divided by the average population of a locality. So in this cases, the incidence rate measures the number of measles cases reported to the CDC adjusted for each state’s population. The chart is ordered from the states with the highest average incidence rate at the top and the states with the lowest rates at the bottom. I gathered the data for this visualization from Project Tycho, a database maintained by the University of Pittsburgh. The researchers at Project Tycho culled their data from weekly surveillance reports from the NNDSS. Specifically, I used Level 1 data, which has been standardized into a common format for easier analysis.


I provide more context below.


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