Science

Researchers from NYU Langone Medical Center have found evidence that sleep promotes memory by strengthening dendritic spines that grow during learning tasks. The study, published this month, was led by Guang Yang, Cora Sau Wan Lai, Joseph Cichon, Lei Ma, Wei Li and Wen-Biao Ga set out to discover the means by which sleep helps learning and memory, which are currently unknown.

Yang et al. observed memories forming and strengthening in mice. When the mice learned motor tasks, “spines”–protuberances–formed on dendritic  branches of specific neurons. These spines represent the formation of a new memory. Such dendritic structures are subject to strengthening and decay.

When mice slept after forming a new memory, the spines were retained better. Not only that: the researchers observed the refiring of neurons that had fired during learning. The refiring occurred during slow-wave sleep. Another way of phrasing this finding is that sleep after motor learning promotes the formation of postsynaptic dendritic spines on a subset of branches of individual layer V pyramidal neurons.

Slow wave is deep sleep. when EEG activity is synchronized, producing slow waves with a low frequency and relatively high amplitude. Slow wave sleep has two stages: a down state in which neurons in the neocortex are silent and at rest, and a up state in which neurons fired excitedly for a brief period. Slow wave sleep proceeds REM sleep.

The research findings have brought science one step closer to understanding the process of sleep. The findings indicated to the NYU team that sleep has a key role in promoting learning-dependent synapse formation and maintenance on selected dendritic branches, and contribute to the storage of memories.

By Sid Douglas

Science

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By smashing massless photons together, light can be converted into matter, according to physicists at London’s Imperial College, and the race to conduct the experiment is on–and should be carried out within the year. Until now, the idea of converting E into mc2 had been considered practically impossible.

“The race to carry out and complete the experiment is on,” said Imperial College London’s Oliver Pike. The experiment is now possible because physicists are able increase the number of photons to massive levels (billions of times the level of normal visible light) in order to achieve collisions in a photon-photon collider. The tiny size of photons was until recently a near-impossible obstacle to the experiment.

The proposed means of achieving massive photon levels is a photon-photon collider in a vacuum hohlraum. The apparatus consists of a high-powered laser, which bombards a slab of gold, producing a high-intensity gamma ray (photons) a hallow space (“hohlraum”) in which is accumulated a thick field of photons produced by another laser. The gamma ray bombards the hohlraum. Out of the other end of the hohlraum some electrons and positrons will fly, according to the English physicists. A shorter, more technical phrasing of the process is that a gamma-ray beam is fired into the high-temperature radiation field of a laser-heated hohlraum.

The theory of converting light into matter and matter into light dates back to 1930, when theoretical physicist Paul Dirac considered that an electron and its antimatter counterpart (a positron) could be annihilated (combined) to produce two photons. Four years later, physicists Gregory Breit and John Wheeler suggested that the reverse could also be true.

“It’s breathtaking to think that things we thought are not connected, can in fact be converted to each other: matter and energy, particles and light. Would we be able in the future to convert energy into time and vice versa?” said John Adams Institute, Oxford Director Andrei Seryi of the John Adams Institute on the matter.

Many laboratories around the world have the equipment necessary to perform the experimental photon-photon collisions, the English physicists say, and the experiment is expected to be conducted within the year.

By Andy Stern

Nature Photonics

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NASA, planning a mission to the moon Europa–one of the best candidates for life-sustaining habitation–within the next 10 years, has opened the door for crowdsourced talent. The goal is to create a mission for under $1 billion. NASA has published a Request for Information (RFI) seeking creative help.

Although much smaller than the Earth, Europa is thought to contain more water than our planet, and last year jets of water were observed shooting out of the moon’s icy surface, causing scientists to strongly suspect the existence of water plumes.

With NASA’s RFI, it hopes to address several fundamental questions about the enigmatic moon and life beyond earth, and on a budget. NASA provided a list of its five top goals for Europa:

1. Characterize the extent of the ocean and its relation to the deeper interior;
2. Characterize the ice shell and any subsurface water, including their heterogeneity, and the
nature of surface-ice-ocean exchange;
3. Determine global surface compositions and chemistry, especially as related to habitability;
4. Understand the formation of surface features, including sites of recent or current activity,
and identify and characterize candidate sites for future in situ exploration;
5. Understand Europa’s space environment and interaction with the magnetosphere.

The $1 billion target excludes the launch vehicle, but includes everything else, including all the technology and scientific intstruments needed for the mission. Some considerations specifically mentioned by NASA in the RFI for the Europa mission include the extreme radiation environment and protection of Europa’s potentially inhabitable ocean from the Earth’s bacteria.

NASA has released Request for Information: NNH14ZDA008L Europa Mission Concepts Costing Less than $1 Billion, targeting science and engineering communities. The RFI includes details about what and how to submit to NASA.

By Day Blakely Donaldson

Source:

NASA