Knowledge Update

​Phnom Penh, Jan 2 (IANS) The National Museum of Cambodia in January will exhibit what is considered by some experts to be the world's oldest zero symbol, a dot in a set of script from the Khmer civilisation carved into a sandstone surface.

"The Chaka era has reached the year 605 on the fifth day of the waning moon," says the restored inscription discovered during the end of the 19th century at the Trapang Prei archaeological site in Kratie province, in northeastern Cambodia.

Archaeologists date this phrase to 687 AD, in pre-Angkor Cambodia, Efe news reported on Monday.

This Khmer inscription was discovered by French archaeologist Adhemard Leclere (1853-1917) in 1891, but his colleague and compatriot George Coedes (1886-1969) later classified it with the name K-127.

The same historian Coedes subsequently divulged the importance of the discovery in the article "About the Origin of Arabic Numbers", published in 1931.

Coedes and American mathematician Amir Aczel (1950-2015) defended the significance of K-127 as it strengthens the idea that the zero symbol's origin in the decimal number system comes from India or, in his word, other "Indianized" East Asian cultures.

The oldest zero that is known of and in the form of a circle, rather than a dot, comes from India and from the year 876 AD, almost two hundred years earlier than the one at the National Museum of Cambodia.

The Indian manuscript Bakhshali also contains zeros that could be prior to K-127, but the experts are unable to determine their antiquity with current technology due to the fragility of the object.

A civilization influenced by the Indian culture that existed in the south of the Indonesian island of Sumatra has also passed on another stone-carved dot equivalent to a zero to us, but it is from the year 688 AD, a few years before the aforementioned Khmer inscription.

The Maya and other pre-Columbian cultures knew this figure and used it in their hieroglyphs and calendars, but their numeral system did not survive the passage of time.

Cambodia has many inscriptions with the zero symbol, "but this one (K-127) is the oldest one," Chea Socheat, deputy director of the restoration department at the National Museum of Cambodia, told Efe news.

Representing the absolute lack of quantity or a null value and being of paramount importance in mathematics, this number entered Europe through the Arabs, who called it "sirf" (void).

The popularization of the Hindu-Arabic numerical system among the Europeans corresponds to the Italian mathematician Leonardo de Pisa (1170-1250), better known as Fibonacci.

"Zero is not just a concept of nothingness, which allows us to do arithmetic efficiently, but is also a place-holding device that enables our base-10 number system to work," Aczel said in his book "Finding Zero: A Mathematician's Odyssey to Uncover the Origins of Numbers."

According to anthropologist Miriam Stark from the University of Hawaii and an expert on Cambodia, the numeral system was fundamental for constructing temples during the Khmer empire or Angkor Empire (802-1431), such as the famous Unesco World Heritage site, Angkor Wat complex, in the city of Siem Reap.

The capital of this empire, Angkor, was the largest urban complex in the pre-industrial world, with a population of about 1 million people living in 1,000 sq.km of territory, according to Damian Evans, Christophe Pottier and other anthropologists.

Inscriptions like the K-127 help us learn about the past, according to Socheat, and the history of the numbers. 

New York, Jan 2 (IANS) Feeling too lazy to hit the gym or follow an exercise routine? Your altered dopamine receptors -- critical for movement -- may be the reason behind your lack of motivation rather than excess body weight, a new study has suggested. The study challenged a common belief that obese animals do less physical activity, because carrying extra body weight is physically disabling. "We know that physical activity is linked to overall good health, but not much is known about why people or animals with obesity are less active," said Alexxai V. Kravitz from the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)- a part of the National Institutes of Health in the US. For the study, mice were fed either a standard or a high-fat diet for 18 weeks. Beginning in the second week, the mice on the unhealthy diet had higher body weight. By the fourth week, these mice spent less time moving and got around much more slowly when they did move. The results showed that the high-fat diet mice slowed down their activity, but they did it before they actually got fat instead of after, suggesting that the excess weight alone was not responsible for the reduced movements. The reason the mice were inactive was due to dysfunction in their dopamine systems. They had deficits in the D2 dopamine receptors, the researchers said. "There are probably other factors involved as well, but the deficit in D2 is sufficient to explain the lack of activity," said Danielle Friend, postdoctoral student at NIDDK. The study appeared in the journal Cell Metabolism.

Sydney, Jan 2 (IANS) The rapid growth in wing length of a common Western Australian bird may be related to climate change, according to a study released on Monday.

Scientists from the University of Notre Dame in Sydney linked the growth in wing length of the Australian ringneck parrot, or Barnardius zonarius, to climate change as the limbs of animals in warm climates tend to be longer, Efe news reported.

The wings of the parrot lengthened 4 to 5 cm in the last 45 years.

As temperatures rise, the increase in the length of wings can help these birds release excess heat and adapt better to their environment, said one of the study's scientists, Dylan Korczynskyj.

Korczynskyj explained that the biggest changes in wing length have occurred since the 1970s, a period that coincides with temperature changes of more than 0.1 to 0.2 degrees Celsius and deforestation carried out in the state of Western Australia.

Although temperature variation appears minimal, the impact on the environment is significant, as evidenced by research on the bird species, he added.

The study examined several specimens from the museum of Western Australia, which has a collection of birds dating back to the early 19th century and includes a ringneck parrot specimen from 1904.

​New York, Jan 1 (IANS) Researchers have designed molecules with the potential to deliver healing power to stressed cells -- such as those involved in heart attacks.

The research, at a cellular level in the laboratory, involves organic molecules that break down to release hydrogen sulphide when triggered by specific conditions such as increased oxidative stress.

Oxidative stress damages cells and is tied especially to heart disease and cancer as well as Alzheimer's and Parkinson's disease.

"We have discovered that small organic molecules can be engineered to release a molecule called carbonyl sulphide, which is the most prevalent sulphur-containing molecule in the atmosphere, but more importantly converts rapidly to hydrogen sulphide under biological conditions," said study co-author Michael Pluth, Professor at the University of Oregon in the US.

"We developed and demonstrated a new mechanism to release small molecules that provide therapeutic hydrogen sulphide," Pluth said.

Hydrogen sulphide, a colourless gas, has long been known for its dangerous toxicity -- and its telltale smell of rotten eggs -- in the environment, but it also is produced in mammals, including humans, with important roles in molecular signalling and cardiac health.

One of the goals of developing these small hydrogen sulphide-releasing molecules is the potential for long-term applications in therapeutics, Pluth said.

Separate portions of the research were detailed in the Journal of the American Chemical Society and in an international journal Angewandte Chemie.

​New York, Jan 1 (IANS) A gene mutation linked to Alzheimer's disease and other age-related cognitive declines in our relatively safe and sterile post-industrial setting might have actually helped protect us from cognitive decline in ancient times, a new research suggests.

The findings suggest that a genetic mutation (or allele) that puts populations at risk for illnesses in one environmental setting could manifest itself in positive ways in a different setting.

"It seems that some of the very genetic mutations that help us succeed in more hazardous time periods and environments may actually become mismatched in our relatively safe and sterile post-industrial lifestyles," said lead author Ben Trumble, Assistant Professor at the Arizona State University in the US.

In a paper published in The FASEB Journal, the researchers examined how the apolipoprotein E (ApoE) gene might function differently in an infectious environment than in the urban industrialised settings where ApoE has mostly been examined.

All ApoE proteins help mediate cholesterol metabolism, and assist in the crucial activity of transporting fatty acids to the brain.

But in industrialised societies, ApoE4 variant carriers also face up to a four-fold higher risk for Alzheimer's disease and other age-related cognitive declines, as well as a higher risk for cardiovascular disease.

The goal of this study was to reexamine the potentially detrimental effects of the globally-present ApoE4 allele in environmental conditions more typical of those experienced throughout our species' existence -- in this case, a community of Amazonian forager-horticulturalists called the Tsimane.

"For 99 per cent of human evolution, we lived as hunter gatherers in small bands and the last 5,000-10,000 years -- with plant and animal domestication and sedentary urban industrial life -- is completely novel," Trumble said.

Due to the tropical environment and a lack of sanitation, running water, or electricity, remote populations like the Tsimane face high exposure to parasites and pathogens, which cause their own damage to cognitive abilities when untreated.

As a result, one might expect Tsimane ApoE4 carriers who also have a high parasite burden to experience faster and more severe mental decline in the presence of both these genetic and environmental risk factors.

But researchers discovered the exact opposite when they tested these individuals using a seven-part cognitive assessment and a medical exam.

In fact, Tsimane who both carried ApoE4 and had a high parasitic burden displayed steadier or even improved cognitive function in the assessment versus non-carriers with a similar level of parasitic exposure.

This indicated that the allele potentially played a role in maintaining cognitive function even when exposed to environmental-based health threats.

​London, Jan 2 (IANS) Scientists have for the first time identified a mechanism that regulates rhythmic brain waves that play a key role in making our memories permanent.

Memories undergo a consolidation process which stabilises and makes them become stronger -- a process where brain waves play an important role, the study said. 

The study revealed that one of the brain waves -- sharp wave ripples (SWRs) -- needed for consolidating memories is dominated by synaptic inhibition. 

It helps the brain set what an individual has learned or experienced as a quick instant replay.

SWRs is one among the three major brain waves coming from the hippocampus region of the brain that plays a key role in our memory making.

"Our results were able to show that precisely timed synaptic inhibition is the current generator for sharp wave ripples," said Peter Jonas, Professor at the Institute of Science and Technology Austria (IST Austria).

In the study, conducted in mice, the team set out to find the SWR mechanism -- whether ripples are caused by a temporal modulation of excitation or of inhibition at connecting points in brain cells, or synapses. 

The findings showed that the frequency of both excitation and inhibitor events at the synapse increased during the SWR.

But, synaptic inhibition was found to dominate over excitation during the production of SWRs, which means synaptic inhibition is responsible for forming the shape and rhythm of sharp wave ripples. 

Finally, the researchers also identified the neurons -- PV+ interneurons -- that provide inhibitory output onto other neurons and are mainly responsible for creating SWRs.

"Inhibition ensures the precise timing of neuronal firing. This could be critically important for preplay or replay of neuronal activity sequences and the consolidation of memory. 

"Inhibition may be the crucial player to making memories permanent," explained Jian Gan, post-doctoral student at IST Austria, in the paper published in the journal Neuron.

​New York, Jan 1 (IANS) Premixed complementary foods sold in lower-income countries lack consistency in their nutritional content, a global analysis of infant cereals has revealed.

The findings suggest that there is a need for basic quality assurance services to improve nutritional consistency and healthy growth of infants from 6 to 24 months age.

Premixed infant cereals or complementary foods can be a vital source of the solid food needed for healthy child growth after the age of six months, when infants outgrow the nutrients provided by breast milk alone.

This conclusion was reached after researchers from Tufts University in the US analysed 108 commercially available premixed complementary foods from 22 low-and-middle-income countries.

The findings, published in the journal Maternal and Child Nutrition, said premixed complementary foods can be extremely effective at protecting infants against malnutrition and stunted growth.

"In countries where we sampled, some products can readily meet children's needs, but others fall far below requirements for both macro and micro-nutrients," said William Masters from Tufts University.

"Our results are a call to action for establishing and enforcing nutritional quality standards, which would help ensure access to lower-cost, higher-quality products and enable parents to meet their infants' needs more easily," he added.

Researchers said that childhood malnutrition was the main cause of stunted growth, that may lead to delayed mental development and poor school performance -- a serious and irreversible condition that affects individuals with greater risk for illness and death throughout their lives.

According to Unicef, nearly half of all deaths in children under age five are related to undernutrition, which is particularly widespread in Africa and Asia.

"A healthy child consuming breast milk alongside the average sampled complementary food would experience zinc and iron deficiency from six to nine months, and dietary fat deficiency at 12 months," the study said.

The study noted that nutritional content claims on packaging labels did not meet their reported caloric content.

"Slightly more than half of the products misreported protein, and two thirds misreported fat content. For zinc and iron, products exceeded labelled values about as often as they fell short," the study further added.

​Beijing, Dec 31 (IANS) China will ban the processing and sale of ivory for commercial purposes by the end of 2017, closing down the world's biggest ivory market, officials reported on Saturday.

​New York, Dec 27 (IANS) The $26.2 billion acquisition of LinkedIn can propel technology giant Microsoft to be the first tech company to attain a market value of $1 trillion, an analyst has said.

​Tokyo, Dec 26 (IANS) Examining cucumber seedlings germinated under the very weak gravity -- or microgravity -- conditions of the International Space Station, researchers from Japan's Tohoku University have discovered how a protein helps plants sense gravity to boost their chances of survival.

Plants are experts in survival and can control the direction of their roots to maximise the use of resources around them. 

Using specialised cells, they can sense gravity and redistribute hormones, called auxins, to stimulate growth and allow vital features of the plant to develop. 

However, a big puzzle is how this transport process occurs at a cellular level.

In this study, reported in the journal Nature Microgravity and using samples grown on board the International Space Station, the research team highlighted the valuable contribution of the gravity-sensitive CsPIN1 protein to this process. 

The role of the protein in facilitating the transport of the growth hormones had first been suggested in previous experiments conducted on Earth.

To gain further insight, the researchers loaded cucumber seeds into specially designed canisters, which were sent up to the space station. 

Cucumbers were chosen for the study as they -- like other "cucurbitaceous" seedlings such as melons, pumpkins and squash -- feature specialised protuberances, or pegs, whose formation is regulated by gravity. 

These pegs form during the plant's early growth stage to help the seedlings emerge from their hard seed coat and anchor the developing plant in the soil while its roots form.

The experiment showed that CsPIN1 protein can relocalise under the influence of gravity.

Specifically, this change in the position of protein was found to occur in the so-called transition zone of the cucumber seedling where the pegs develop. 

This behaviour stimulates the formation of a cellular canal capable of transporting growth hormones from one side of this zone to the other, the study said.

Put simply, these findings point towards the mechanism by which the seeds are able to turn on and off the growth of their anchoring pegs in relation to their orientation with respect to gravity. And, as result, boost their chances of survival.