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SciTechPress

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  1. A common misconception is that light travels at different speeds through different mediums. People say that the speed of light in a vacuum is cc, and then say that the speed of light through glass is slower than cc. This simply is not true.

    The speed of light is always cc. Then why does it take longer for it to travel through glass? Experiments show that light "moves about  200000 km/s through glass" (as opposed to 300,000 km/s through a vacuum), so how could the speed of light be constant?

    Because of this little thing called interaction.

    Imagine you are receiving a prize, maybe for writing a great paper about physics. As you walk from point A to point B, you take 2 steps every second. The walkway, being 60 steps long, takes you 30 seconds to get from A to B. Your pathway looks like this.

    Pretty simple right? I would think so. 

    But let's say you didn't win the prize just by yourself. Some people also helped. In this case, you might want to thank your contributors as you walk to the prize. If you walk at a speed of 2 steps a second, it takes you 120 seconds now to get from the same point A, to the same point B. How is this possible? Both times you were walking at 2 steps a second, yet it took twice as much time as before? Well, let's take a step back and look at the picture.

    Well that explains it. You were moving both times at 2 steps a second, but you interacted with other external things.

    Now, let's substitute you for light, the walkway for glass, and the contributors for glass molecules.

    No matter what, light is always moving at cc. The speed of light does not change in a vacuum, but the time from point A to point B does change, depending on what interacts with the light.

    So in short, no, light does not change speeds depending on the medium it travels through. The speed of light is always cc.

    Ignacio Cabero


  2. The following images were taken near Roatan, a Caribbean island in Honduras by photographer Caroline Power, and show a sea of plastic glued together, floating like a massive turf in the middle of the ocean. The area where the images were taken is usually compared to paradise, although based on these images it looks anything but that at the moment. Who should we blame? The answer is simple: Society and our way of life. The images show just how bad pollution is, not only in the Caribbean but in many other places around the globe.

    Sea-of-Garbage.jpg

     

    The worst part is that itÂ’s not only unappealing to the eye, but itÂ’s also threatening to kill off marine life due to irreparable damage done to the environment.

    The images taken by Power were taken as she and her dive team set out to explore the Caribbean when they encountered a floating island of garbage that stretches for a staggering five miles.

    As they made their way through the patch of floating rubbish, they encountered everything from plastic bottles, soda cans, televisions, and shoes.

    Ms. Power went on facebook and posted the images with a post titled: “THIS HAS TO STOP. Think about your daily lives.

    “How did you take your food to go last time you ate out? How was your last street food served?

    Floating-plastic-island-in-the-Caribbean.jpg

    Plastic-floating.jpg

     


  3. tumblr_otc0qatlGi1rvcmm7o1_500.jpg

    bpod-mrc:

    Growing Nerves

    Our nervous system is made up of the brain, spinal cord and neurons [nerves] – an intricate network that allows our brain to communicate with the rest of our body. Development of the human nervous system begins when an embryo is in its 5th week. Neurons extend a projection from their cell body called the axon (pictured in green, pink and blue in a developing mouse spinal cord) along a specific path in response to a variety of molecular cues, systematically guiding its journey to the spinal cord (left) and eventually the wider body, establishing the nervous system. One particular molecular cue called netrin1 organises axon growth, but researchers have been trying to understand how. By halting the activity of netrin1, axon growth was disrupted and highly disorganised (right), highlighting how netrin1 influences axon growth and providing insight into how researchers could regenerate axons in people with nerve damage.

    Written by Katie Pantell

    You can also follow BPoD on Instagram, Twitter and Facebook

    via ScitechPress.org


  4. neurosciencestuff:

    Nerve cells in our brains work together in harmony to store and retrieve short-term memory, and are not solo artists as was previously thought, Western-led brain research has determined.

    The research turns on its head decades of studies assuming that single neurons independently encode information in our working memories.

    “These findings suggest that even neurons we previously thought were ‘useless’ because they didn’t individually encode information have a purpose when working in concert with other neurons,” said researcher Julio Martinez-Trujillo, based at the Robarts Research Institute and the Brain and Mind Institute at Western University.

    “Knowing they work together helps us better understand the circuits in the brain that can either improve or hamper executive function. And that in turn may have implications for how we work though brain-health issues where short-term memory is a problem, including Alzheimer disease, schizophrenia, autism, depression and attention deficit disorder.”

    Working memory is the ability to learn, retain and retrieve bits of information we all need in the short term: items on a grocery list or driving directions, for example. Working memory deteriorates faster in people with dementia or other disorders of the brain and mind.

    In the past, researchers have believed this executive function was the job of single neurons acting independently from one another – the brain’s version of a crowd of people in a large room all singing different songs in different rhythms and different keys. An outsider trying to decipher any tune in all that white noise would have an extraordinarily difficult task.

    This research, however, suggests many in the neuron throng are singing from the same songbook, in essence creating chords to strengthen the collective voice of memory. With neural prosthetic technology – microchips that can “listen” to many neurons at the same time – researchers are able to find correlations between the activity of many nerve cells. “Using that same choir analogy, you can start perceiving some sounds that have a rhythm, a tune and chords that are related to each other: in sum, short-term memories,” said Martinez-Trujillo, who is also an associate professor at Western’s Schulich School of Medicine & Dentistry.

    And while the ramifications of this discovery are still being explored, “this gives us good material to work with as we move forward in brain research. It provides us with the necessary knowledge to find ways to manipulate brain circuits and improve short term memory in affected individuals,” Martinez-Trujillo said.

    “The microchip technology also allows us to extract signals from the brain in order to reverse-engineer brain circuitry and decode the information that is in the subject’s mind,” said Adam Sachs, neurosurgeon and associate scientist at The Ottawa Hospital and assistant professor at the University of Ottawa Brain and Mind Research Institute. “In the near future, we could use this information to allow cognitive control of neural prosthetics in patients with ALS or severe cervical spinal cord injury.”

    via ScitechPress.org


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