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Comment by Dr. Krishna Kumari Challa on February 6, 2016 at 11:20am

Mothers who are obese during pregnancy have almost twice the odds of having a child with autism as women who weigh less, a U.S. study suggests.
When women are both obese and have diabetes, the autism risk for their child is at least quadrupled, researchers reported online January 29 in Pediatrics.

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Comment by Dr. Krishna Kumari Challa on February 4, 2016 at 7:06am

Model of Sun's magnetic field:

Comment by Dr. Krishna Kumari Challa on February 3, 2016 at 8:41am

Ocean acidification and warming could affect the culturing of pearls
Pearl aquaculture is big business, particularly in Asia and Australia. But much of it takes place in oceans, which are susceptible to the increasing amounts of carbon dioxide human activity releases into the atmosphere. CO2 from the air gets absorbed by the oceans, which become more acidic as a result. Research has found that pearl oysters produce weaker shells under these conditions, and this could hurt their chances of survival. But in addition to acidity, rising water temperature could also play a role in oyster health.
- Environmental Science & Technology

http://phys.org/news/2016-01-ocean-acidification-affect-culturing-p...

Comment by Dr. Krishna Kumari Challa on February 3, 2016 at 8:36am

Occupational exposure to textile dust increases the risk of rheumatoid arthritis: results from a Malaysian population-based case–control study
Lung exposures including cigarette smoking and silica exposure are associated with the risk of rheumatoid arthritis (RA). Now scientists say association between textile dust exposure and the risk of RA in the Malaysian population is real whose correctness has been established with a focus on women who rarely smoke.
Results of the study: Occupational exposure to textile dust was significantly associated with an increased risk of developing RA in the Malaysian female population (OR 2.8, 95% CI 1.6 to 5.2). The association between occupational exposure to textile dust and risk of RA was uniformly observed for the ACPA-positive RA (OR 2.5, 95% CI 1.3 to 4.8) and ACPA-negative RA (OR 3.5, 95% CI 1.7 to 7.0) subsets, respectively. We observed a significant interaction between exposure to occupational textile dust and HLA-DRB1 SE alleles regarding the risk of ACPA-positive RA (OR for double exposed: 39.1, 95% CI 5.1 to 297.5; AP: 0.8, 95% CI 0.5 to 1.2).

Conclusions of the study: This is the first study demonstrating that textile dust exposure is associated with an increased risk for RA. In addition, a gene–environment interaction between HLA-DRB1 SE and textile dust exposure provides a high risk for ACPA-positive RA.
http://ard.bmj.com/content/early/2015/11/08/annrheumdis-2015-208278...

Comment by Dr. Krishna Kumari Challa on February 3, 2016 at 6:06am

Chromosomes must be accurately segregated during the production of sex cells to ensure that the next generation inherits an intact copy of the genome. However, this process is particularly error-prone in women and gets worse as they get older. Errors in chromosome segregation produce egg cells with the wrong number of chromosomes, which can lead to infertility and Down syndrome .
New eggs develop from immature egg cells (or oocytes) via meiosis: this process involves the original cell’s DNA being replicated once before it divides twice to produce four new cells, each with half the original number of chromosomes. Most errors in the number of chromosomes in human eggs come from mistakes made when the oocyte divides for the first time in a process commonly called meiosis I. Multiple factors can contribute to these errors, but it is not clear which are most significant in human oocytes.
Human oocytes start with 23 pairs of homologous chromosomes, which are split during the anaphase stage of meiosis I so that the egg contains one from each pair. There are two main requirements that must be met during meiosis I. First, each pair of homologous chromosomes must be physically connected to form a “bivalent”. Second, the two sister kinetochores on each chromosome must be functionally fused together so that both sisters connect to the same spindle pole. These two requirements are both compromised in human oocytes. This provides a plausible mechanism to explain the errors often seen in meiosis I in women.
-elifesciences.org

http://elifesciences.org/content/5/e13788?utm_source=content_alert&...

Comment by Dr. Krishna Kumari Challa on February 2, 2016 at 8:36am

Small ponds produce an outsized share of greenhouse gases
Tiny ponds play a disproportionately large role in global greenhouse gas emissions from inland waters, according to a new study by Yale's School of Forestry & Environmental Studies.
The reason has to do with the physical makeup of very small ponds and the way they cycle carbon. Small ponds have a high perimeter-to-surface-area ratio, for example, and accumulate a higher load of terrestrial carbon -- so-called "leaf litter," sediment particles and other material. Small ponds also tend to be shallow, which means their terrestrial carbon loads are highly concentrated compared to larger lakes. Lastly, gases produced at the bottom of these ponds are able to reach the top more often than what occurs in larger lakes, due to greater water mixing and shallower waters. Because of this, CO2 and CH4 generated in sediments affects the entire pond.

That makes small ponds an important player in the carbon cycle.
The carbon cycling that happens in freshwater systems needs to be accounted for in estimates of terrestrial production. These numbers are important to quantifying the global carbon cycle and making predictions about future stocks and flows of carbon.

Although ponds less than a quarter of an acre in size make up only 8.6% of the surface area of the world's lakes and ponds, they account for 15.1% of carbon dioxide (CO2) emissions and 40.6% of diffusive methane (CH4) emissions. The findings appear in the Feb. 1 online edition of the journal Nature Geoscience.

Comment by Dr. Krishna Kumari Challa on February 2, 2016 at 8:27am

UK scientists just got approval to edit human embryos
Scientists in Britain just got approval to conduct research that involves editing the genetic material of healthy human embryos.

This is a big deal: The UK's Human Fertilisation and Embryology Authority is the first government agency in the world to endorse research that involves altering the human genome for research — a move that could signal broader acceptance for a promising (but controversial) new area of science.

The research team, led by Dr. Kathy Niakan at the UK's Francis Crick Institute, is trying to better understand which genes allow a healthy human embryo to develop. Niakan’s team will use a promising new technique, known as CRISPR/Cas9, to edit genes that are active following conception. They'll then stop the experiments at day seven and destroy the embryos (so that they can't be used to start a pregnancy).

The hope is that this gene hacking could help researchers better understand what causes miscarriages and infertility — and perhaps one day lead to better treatments for infertility.

Comment by Dr. Krishna Kumari Challa on February 2, 2016 at 8:20am

New evidence emerges for 'transmissible Alzheimer's' theory:
Autopsies reveal plaques in the brains of people who died after receiving grafts from cadavers.

For the second time in four months, researchers have reported autopsy results that suggest Alzheimer’s disease might occasionally be transmitted to people during certain medical treatments — although scientists say that neither set of findings is conclusive.
The latest autopsies, described in the Swiss Medical Weekly1 on 26 January, were conducted on the brains of seven people who died of the rare, brain-wasting Creutzfeldt–Jakob disease (CJD). Decades before their deaths, the individuals had all received surgical grafts of dura mater — the membrane that covers the brain and spinal cord. These grafts had been prepared from human cadavers and were contaminated with the prion protein that causes CJD.

But in addition to the damage caused by the prions, five of the brains displayed some of the pathological signs that are associated with Alzheimer’s disease, researchers from Switzerland and Austria report. Plaques formed from amyloid-β protein were discovered in the grey matter and blood vessels. The individuals, aged between 28 and 63, were unusually young to have developed such plaques. A set of 21 controls, who had not had surgical grafts of dura mater but died of sporadic CJD at similar ages, did not have this amyloid signature.
According to the authors, it is possible that the transplanted dura mater was contaminated with small ‘seeds’ of amyloid-β protein — which some scientists think could be a trigger for Alzheimer’s — along with the prion protein that gave the recipients CJD.
http://www.smw.ch/content/smw-2016-14287/
http://www.nature.com/news/autopsies-reveal-signs-of-alzheimer-s-in...

Comment by Dr. Krishna Kumari Challa on January 31, 2016 at 11:04am

Till now we are under the impression that earthworms are highly beneficial to plants. But listen to this:  Earthworms not always beneficial, may threaten plant diversity!

A new study suggests that an abundance of earthworms in soils could lead to reductions in the number of trees and and other plant species.

Contrary to the popular belief that these creatures and beneficial to the natural ecosystem, the scarcity of these invertebrates can be a threat to certain plant species, causing adverse effects on the ecosystem.

Researchers from Canada's Université Laval and Université de Sherbrooke visited sugar maple forests in Quebec province where they found half of which were populated by earthworms.

Their analysis revealed a correlation between the number of earthworms and the abundance and diversity of certain understory species as they found that new shoots of red maple, striped maple, American beech, and two fern species became rarer as populations of these invertebrates increased.

"The most likely explanation is that the earthworms consume organic matter in forest litter," said Line Lapointe, a professor at Université Laval's faculty of science and engineering and the study's lead author.

"This results in soils that can't hold as much moisture, and that in turn interferes with seed germination and the ability of some species' plantlets to survive," she added.

Earthworms have started to change plant composition in sugar maple forests, according to the researchers.

Researchers suggest that earthworms used for bait should never be released in the forest, instead they be thrown into the lake to avoid overpopulation in the ecosystem.

The study has been published in the journal Forest Ecology and Management.

Comment by Dr. Krishna Kumari Challa on January 30, 2016 at 7:39am

Electrons do not orbit around an atomic nucleus like planets around a star. This outdated model of the atom (called the Bohr-Rutherford model) is still taught in schools, but only as an introduction to modern ideas about the atom.

Max Born showed us that electrons do not have a definite position, but instead exist as probability wave functions that describe how likely it is that the electron would be at a particular point in its atomic orbit. That is to say, the electron exists in a superposition of all possible locations around the atom. Werner Heisenberg discovered that it isn't until an electron is observed (detected by an instrument) that its wave function collapses and it takes on a discrete location.

So, really, electrons do not orbit around a nucleus; they exist in all possible locations around that nucleus simultaneously. Quantum mechanics!

Electrons don't orbit around atomic nucleuses like planets around a star. But that doesn't mean that they aren't moving.

The probability density for an electron is symmetric around the nucleus, so the average velocity would cancel out to zero. So let's calculate a typical speed from the square-root of the average velocity squared instead. (This is the referred to as root-mean-squared or r.m.s. for short.)

It's actually pretty easy to figure out the r.m.s. velocity for a typical electron from a few physics facts.

First, we need to the know the binding energy of the electron to the nucleus. We might as well assume it's in hydrogen, the simplest atom, so it has total binding energy of E = -13.6 eV (electron-volts):

Next, we need to know what part of the energy is kinetic (moving) instead of potential (due to the electric force holding the atom together). For closed orbits (electrons or planets), there is very handy relationship known as the Virial Theorem [1]. The Virial Theorem tells us that for particles experiencing an attractive 1/r21/r2 force like that between opposite charges, the average kinetic energy is equal to the negative of the total energy:
⟨T⟩=−E⟨T⟩=−E.

To calculate the r.m.s. velocity, we just need the non-relativistic [2] formula relating kinetic energy T and velocity v:
T=12mv2T=12mv2,
where m is the mass of the object.

Solving the above equations, we find:
vrms=−2Em−−−−√.vrms=−2Em.
Plugging in the binding energy and mass of an electron, we see that our hypothetical electron is moving at 2.2*10^6 m/s [3] or just shy of 5 million mph. Fast, but still about a factor of 100 times slower than the limit, the speed of light.

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