Tuesday, June 30, 2020

Eyes in the Sky - UNIVERSE


Why are plants green?


When sunlight shining on a leaf changes rapidly, plants must protect themselves from the ensuing sudden surges of solar energy. To cope with these changes, photosynthetic organisms — from plants to bacteria — have developed numerous tactics. Scientists have been unable, however, to identify the underlying design principle.
An international team of scientists, led by physicist Nathaniel M. Gabor at the University of California, Riverside, has now constructed a model that reproduces a general feature of photosynthetic light harvesting, observed across many photosynthetic organisms.
Light harvesting is the collection of solar energy by protein-bound chlorophyll molecules. In photosynthesis — the process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water — light energy harvesting begins with sunlight absorption.
The researchers’ model borrows ideas from the science of complex networks, a field of study that explores efficient operation in cellphone networks, brains, and the power grid. The model describes a simple network that is able to input light of two different colors, yet output a steady rate of solar power. This unusual choice of only two inputs has remarkable consequences.
“Our model shows that by absorbing only very specific colors of light, photosynthetic organisms may automatically protect themselves against sudden changes — or ‘noise’ — in solar energy, resulting in remarkably efficient power conversion,” said Gabor, an associate professor of physics and astronomy, who led the study appearing today in the journal Science. “Green plants appear green and purple bacteria appear purple because only specific regions of the spectrum from which they absorb are suited for protection against rapidly changing solar energy.”

Gabor first began thinking about photosynthesis research more than a decade ago, when he was a doctoral student at Cornell University. He wondered why plants rejected green light, the most intense solar light. Over the years, he worked with physicists and biologists worldwide to learn more about statistical methods and the quantum biology of photosynthesis.
Richard Cogdell, a botanist at the University of Glasgow in the United Kingdom and a coauthor on the research paper, encouraged Gabor to extend the model to include a wider range of photosynthetic organisms that grow in environments where the incident solar spectrum is very different.
“Excitingly, we were then able to show that the model worked in other photosynthetic organisms besides green plants, and that the model identified a general and fundamental property of photosynthetic light harvesting,” he said. “Our study shows how, by choosing where you absorb solar energy in relation to the incident solar spectrum, you can minimize the noise on the output — information that can be used to enhance the performance of solar cells.”
Coauthor Rienk van Grondelle, an influential experimental physicist at Vrije Universiteit Amsterdam in the Netherlands who works on the primary physical processes of photosynthesis, said the team found the absorption spectra of certain photosynthetic systems select certain spectral excitation regions that cancel the noise and maximize the energy stored.
“This very simple design principle could also be applied in the design of human-made solar cells,” said van Grondelle, who has vast experience with photosynthetic light harvesting.
Gabor explained that plants and other photosynthetic organisms have a wide variety of tactics to prevent damage due to overexposure to the sun, ranging from molecular mechanisms of energy release to physical movement of the leaf to track the sun. Plants have even developed effective protection against UV light, just as in sunscreen.
“In the complex process of photosynthesis, it is clear that protecting the organism from overexposure is the driving factor in successful energy production, and this is the inspiration we used to develop our model,” he said. “Our model incorporates relatively simple physics, yet it is consistent with a vast set of observations in biology. This is remarkably rare. If our model holds up to continued experiments, we may find even more agreement between theory and observations, giving rich insight into the inner workings of nature.”
To construct the model, Gabor and his colleagues applied straightforward physics of networks to the complex details of biology, and were able to make clear, quantitative, and generic statements about highly diverse photosynthetic organisms.
“Our model is the first hypothesis-driven explanation for why plants are green, and we give a roadmap to test the model through more detailed experiments,” Gabor said.
Photosynthesis may be thought of as a kitchen sink, Gabor added, where a faucet flows water in and a drain allows the water to flow out. If the flow into the sink is much bigger than the outward flow, the sink overflows and the water spills all over the floor.
“In photosynthesis, if the flow of solar power into the light harvesting network is significantly larger than the flow out, the photosynthetic network must adapt to reduce the sudden over-flow of energy,” he said. “When the network fails to manage these fluctuations, the organism attempts to expel the extra energy. In doing so, the organism undergoes oxidative stress, which damages cells.”
The researchers were surprised by how general and simple their model is.
“Nature will always surprise you,” Gabor said. “Something that seems so complicated and complex might operate based on a few basic rules. We applied the model to organisms in different photosynthetic niches and continue to reproduce accurate absorption spectra. In biology, there are exceptions to every rule, so much so that finding a rule is usually very difficult. Surprisingly, we seem to have found one of the rules of photosynthetic life.”
Gabor noted that over the last several decades, photosynthesis research has focused mainly on the structure and function of the microscopic components of the photosynthetic process.
“Biologists know well that biological systems are not generally finely tuned given the fact that organisms have little control over their external conditions,” he said. “This contradiction has so far been unaddressed because no model exists that connects microscopic processes with macroscopic properties. Our work represents the first quantitative physical model that tackles this contradiction.”
Next, supported by several recent grants, the researchers will design a novel microscopy technique to test their ideas and advance the technology of photo-biology experiments using quantum optics tools.
“There’s a lot out there to understand about nature, and it only looks more beautiful as we unravel its mysteries,” Gabor said.
Source: https://myfusimotors.com/2020/06/27/why-are-plants-green/

UNDERWORLD AWAKENING | VFX Breakdown by Spin VFX (2012)


The Boys Season 2 - First Look Clip "Stormfront" (HD) Superhero Series


Funny and Weird Clips (2067)





















Monday, June 29, 2020

Hubble Spots Giant Flapping Shadow - UNIVERSE


What does the ‘love hormone’ do? It’s complicated


During the pandemic lockdown, as couples have been forced to spend days and weeks in one another’s company, some have found their love renewed while others are on their way to divorce court. Oxytocin, a peptide produced in the brain, is complicated in that way: a neuromodulator, it may bring hearts together or it can help induce aggression. That conclusion arises from unique research led by Weizmann Institute of Science researchers in which mice living in semi-natural conditions had their oxytocin producing brain cells manipulated in a highly precise manner. The findings, which were published in Neuron, could shed new light on efforts to use oxytocin to treat a variety of psychiatric conditions, from social anxiety and autism to schizophrenia.

Much of what we know about the actions of neuromodulators like oxytocin comes from behavioral studies of lab animals in standard lab conditions. These conditions are strictly controlled and artificial, in part so that researchers can limit the number of variables affecting behavior. But a number of recent studies suggest that the actions of a mouse in a semi-natural environment can teach us much more about natural behavior, especially when we mean to apply those findings to humans.
Prof. Alon Chen’s lab group in the Institute’s Neurobiology Department have created an experimental setup that enables them to observe mice in something approaching their natural living conditions — an environment enriched with stimuli they can explore — and their activity is monitored day and night with cameras and analyzed computationally. The present study, which has been ongoing for the past eight years, was led by research students Sergey Anpilov and Noa Eren, and Staff Scientist Dr. Yair Shemesh in Prof. Chen’s lab group. The innovation in this experiment, however, was to incorporate optogenetics — a method that enables researchers to turn specific neurons in the brain on or off using light. To create an optogenetic setup that would enable the team to study mice that were behaving naturally, the group developed a compact, lightweight, wireless device with which the scientists could activate nerve cells by remote control. With the help of optogenetics expert Prof. Ofer Yizhar of the same department, the group introduced a protein previously developed by Yizhar into the oxytocin-producing brain cells in the mice. When light from the wireless device touched those neurons, they became more sensitized to input from the other brain cells in their network.
“Our first goal,” says Anpilov, “was to reach that ‘sweet spot’ of experimental setups in which we track behavior in a natural environment, without relinquishing the ability to ask pointed scientific questions about brain functions.”
Shemesh adds that, “the classical experimental setup is not only lacking in stimuli, the measurements tend to span mere minutes, while we had the capacity to track social dynamics in a group over the course of days.”
Delving into the role of oxytocin was sort of a test drive for the experimental system. It had been believed that this hormone mediates pro-social behavior. But findings have been conflicting, and some have proposed another hypothesis, termed “social salience” stating that oxytocin might be involved in amplifying the perception of diverse social cues, which could then result in pro-social or antagonistic behaviors, depending on such factors as individual character and their environment.
To test the social salience hypothesis, the team used mice in which they could gently activate the oxytocin-producing cells in the hypothalamus, placing them first in the enriched, semi-natural lab environments. To compare, they repeated the experiment with mice placed in the standard, sterile lab setups.
In the semi-natural environment, the mice at first displayed heightened interest in one another, but this was soon accompanied by a rise in aggressive behavior. In contrast, increasing oxytocin production in the mice in classical lab conditions resulted in reduced aggression. “In an all-male, natural social setting, we would expect to see belligerent behavior as they compete for territory or food,” says Anpilov. “That is, the social conditions are conducive to competition and aggression. In the standard lab setup, a different social situation leads to a different effect for the oxytocin.”
If the “love hormone” is more likely a “social hormone,” what does that mean for its pharmaceutical applications? “Oxytocin is involved, as previous experiments have shown, in such social behaviors as making eye contact or feelings of closeness,” says Eren, “but our work shows it does not improve sociability across the board. Its effects depend on both context and personality.” This implies that if oxytocin is to be used therapeutically, a much more nuanced view is needed in research: “If we want to understand the complexities of behavior, we need to study behavior in a complex environment. Only then can we begin to translate our findings to human behavior,” she says.
Source: https://myfusimotors.com/2020/06/23/what-does-the-love-hormone-do-its-complicated/

Mermaids - SNL




What 8 Horror Movies Looked Like Behind The Scenes | Movies Insider


THE GREEN INFERNO - Behind the Scenes: Lorenza Izzo Working in the Amazon


Funny and Weird Clips (2066)