Tag Archives: cold

Do women feel cold more than men in order to create space between the sexes?

Credit: Pixabay.

It’s no secret that women tend to feel the cold more than men, and scientists pin this on metabolic and hormonal differences. But researchers in Israel have proposed an alternative and, frankly, rather outlandish explanation. Their contention is that men and women are evolutionarily inclined to prefer different temperatures to create space between them, thereby curbing aggression and increasing survivability.

The cold gives me space

Dr. Eran Levin of Tel Aviv University’s School of Zoology and colleagues noticed that in many species, males and females are split over their ideal temperature preferences. For their study, the team of researchers analyzed 40 years’ worth of records on the behavior of wild bats and birds in Israel.

They found that male birds and bats tend to prefer higher altitudes, such as near the summit of mountains, while the females preferred to linger in valleys where the temperature is higher. Writing in the journal Global Ecology and Biogeography, where they presented their findings, the scientists added that male mice also prefer colder places than females.

Just like males and females in many species feel pain differently, the researchers in Israel propose that the same nervous system differences may underlie different temperature preferences — and it may all be rooted in evolutionary biology.

“This is because, with birds and bats, it causes genders to be separated outside breeding season, which reduces competition between males over females. It reduces aggression caused by competition for females between males, and reduces aggression toward females and their children,” Levin told Times of Israel.

Besides creating space between males and females, sex-based temperature perception differences may stimulate females to care more for offspring. When females feel cold more, they are more inclined to warm their young, who in many cases require outside action to help with temperature regulation.

“Our findings suggest that females are found in higher ambient temperatures. We term this differential sex-related thermal preference (DSTP) and propose that it is a broad phenomenon common in many endotherms, acting as a significant force shaping dispersal, sociality and behaviour of animals, and should be explored from this wide perspective,” the researchers concluded.

But does this explanation apply to men and women, too? The researchers in Israel seem to think so, claiming that the same evolutionary pressures apply to humans, thereby creating breathing room between the sexes.

“It is meant to make the couple take some distance from each other so that each individual can enjoy some peace and quiet,” said co-author Dr. Tali Magory Cohen.

A study published in the Journal of Applied Physiology found that the resting metabolic rate, the amount of energy the body burns at rest, is 23% higher among men than in women. A slower metabolism means less heat is being produced. Men also tend to have more muscle, which is great for generating heat. Other studies found that estrogen lowers women’s body temperature by causing heat to dissipate and slowing blood flow to the hands and feet.

But are these physiological differences underlined by some evolutionary forces? Perhaps. For instance, humans first surfaced in the warm African savannah, where staying cool was important. Men must have been much more active as they went on hunting and gathering parties, while women tended to children and ‘home base’. Being more active and with larger muscles, men have had to adapt ways of not overheating, which is where sweating comes in. Indeed, men tend to sweat more than women.

Researchers uncover how the freak cold wave of 2018 formed

New research is uncovering the source of the extreme cold wave that hit Europe and Asia during the winter of 2018.

Image via Pixabay.

Last winter, around February, a mass of extremely cold air descended upon Eurasia. The record-breaking cold came from the splitting of a body of air high above the Arctic called the polar vortex, and lasted for almost a month. However, at the time, the incoming mass of cold air wasn’t spotted until it was already upon us.

New research is looking into the origins of this event in a bid to help predict similar weather in the future.

A recipe for cold

“It’s one mechanism that potentially explains a third of these events historically,” said Simon Lee, an atmospheric scientist at the University of Reading, UK, and lead author of the new study. “That just one event in the Atlantic has contributed to a third of them is quite surprising.”

The study reports that a cyclone-induced chain of events led to warming in the stratosphere in 2018 and caused the Arctic polar vortex to split in two, causing the extreme cold. Weather forecast models weren’t able to anticipate the stratospheric warming until the start of February, roughly 2 weeks before it happened, which prevented them from anticipating the extreme cold that followed.

The stratosphere is the second layer of the Earth’s atmosphere. It’s a generally cool, dry place, and it’s also the home of the Arctic polar vortex, which circulates around Earth’s North Pole. If average temperatures in the stratosphere go up, the polar vortex weakens and splits in two, which can cause outbreaks of cold weather across the Northern Hemisphere.

Such stratospheric sudden warming events are generally predicted by observing the troposphere (the part of the atmosphere that we live in). We look at how the troposphere behaved prior to stratospheric events, then we build models to predict what’s going on up there based on what we’re seeing down here. But, these models are imperfect and don’t always catch how temporary weather patterns influence the stratosphere.

The study reports that a cyclone-induced chain of events led to warming in the stratosphere in 2018 and caused the Arctic polar vortex to split in two, causing the extreme cold. Weather forecast models weren’t able to anticipate the stratospheric warming until the start of February, roughly 2 weeks before it happened, which prevented them from anticipating the extreme cold that followed.

Looking at historic weather data, the team found that the same series of events has caused sudden stratospheric warmings in the past. The same unusual weather patterns occurred 49 times between 1979 and 2017, before 35% of the stratospheric warming events recorded over this period.

The team says that their findings help flesh out our understanding of sudden stratospheric warming events. The data suggests that looking for changes in the air masses over Greenland and Scandinavia could help predict extreme cold outbreaks in the future, with weeks or months in advance.

The paper “Abrupt Stratospheric Vortex Weakening Associated With North Atlantic Anticyclonic Wave Breaking” has been published in the Journal of Geophysical Research: Atmospheres.

Frozen flower.

Climate change will make extreme cold more prevalent — and that’s bad news for some animals

It’s important to keep in mind that climate change doesn’t mean only warmer average temperatures — it also fosters weather variability and the prevalence of extreme cold temperature events, a new paper reports.

Frozen flower.

Image credits Manfred Richter.

A team of researchers from Binghamton University investigated the effect of climate change on amphibian health and susceptibility to parasites. The researchers focused on cold weather variability, a less-discussed consequence of climate change, and discovered that it makes amphibians more susceptible to some hazards while lessening the risk of others (such as parasites). They hope the study will help showcase the important role cold weather variability, not just warmer temperatures, play in the context of climate change.

Change goes both ways

“There is a lot of misconception that global climate change only refers to an increase in warming temperatures,” says Jessica Hua, assistant professor of biological sciences at Binghamton and paper co-author. “We feel that the research in this paper is important because it highlights that global climate change is more complex than just an increase in average temperature. In fact, global climate change is also predicted to increase the prevalence of extreme cold temperature events, as well as increase the amount of variation in temperature fluctuations.”

While climate change is recognized as “one of the most serious issues facing us today,” its impact on animal and plant populations isn’t known in depth. Weather variability, in particular, can have dramatic effects on natural systems. For example, rising mean temperatures prompt organisms to breed earlier in the spring, the team explains, which paradoxically increases their risk of experiencing wild fluctuations in temperature during early development — especially cold weather.

These temperatures don’t have to fall into the ‘deadly’ range to cause damage, the team adds, to alter how susceptible amphibians are to other stressors. To investigate the issue further, they placed wood frog embryos in various cold temperature regimes, researchers looked specifically at the consequences of exposure to these lower temperatures.

Amphibians exposed to constant cold conditions as embryos were more susceptible to road salt contamination, but were able to recover as they aged, the team reports. This is particularly relevant, as salt use on roads is predicted to increase exactly as these extreme cold temperature events are taking place. The frogs exposed to cold temperatures as embryos were also smaller overall as they aged, and developed at a slower pace. This ended up protecting them against parasites as their small stature made them less attractive targets.

These results were not anticipated, the team adds, and determining whether the impact from the cold was harmful or helpful for the amphibians overall is difficult to gauge.

“We initially predicted that exposure to cold temperatures would be stressful to developing embryos. As a consequence, we expected that exposure to stressful conditions early in life would make amphibians less able to deal with other stressors later in life (i.e. parasites),” Hua said. “We were also surprised because past studies have found that cooler temperatures can increase amphibian susceptibility to another parasite (the fungus, chytrid). In this case, the negative effects of the cooler temperatures on amphibians are driven by the fact that the fungus survived better in cooler temperatures.”

Amphibian populations are on the decline globally, so considering the effects of cold temperatures may be important in understanding how to better protect them in the future, the team concludes.

The paper “The effects of different cold-temperature regimes on development, growth, and susceptibility to an abiotic and biotic stressor” has been published in the journal Ecology and Evolution.

This series of graphs show the changing density of a cloud of atoms as it is cooled to lower and lower temperatures (going from left to right) approaching absolute zero. The emergence of a sharp peak in the later graphs confirms the formation of a Bose-Einstein condensate -- a fifth state of matter. Credit: NASA/JPL

NASA achieves coldest temperature in space, probes the nature of gravity

This series of graphs show the changing density of a cloud of atoms as it is cooled to lower and lower temperatures (going from left to right) approaching absolute zero. The emergence of a sharp peak in the later graphs confirms the formation of a Bose-Einstein condensate -- a fifth state of matter. Credit: NASA/JPL

This series of graphs show the changing density of a cloud of atoms as it is cooled to lower and lower temperatures (going from left to right) approaching absolute zero. The emergence of a sharp peak in the later graphs confirms the formation of a Bose-Einstein condensate — a fifth state of matter. Credit: NASA/JPL

Earlier this month, a sophisticated science experiment installed on the International Space Station (ISS) chilled rubidium atoms only a fraction of a degree above absolute zero. The conditions caused the cloud of atoms to change into an exotic phase of matter known as Bose-Einstein condensates (BECs). This was the first time BECs have been created in orbit, which offers opportunities to probe the nature of gravity and unify it with other fundamental forces.

Not your typical refrigerator

The four fundamental forces in the universe are electromagnetism, weak and strong nuclear forces, and gravity. Quantum mechanics can explain how the first three interact together at the tiniest scales possible, however, gravity can’t be described in a quantum framework. This is rather problematic and, as such, scientists have been trying for decades to reconcile the fundamental forces with a so-called ‘Theory of Everything.’

There are many jigsaw puzzle pieces that need to be scrambled and fitted before scientists can hope to unify the fundamental forces — and NASA’s Cold Atom Laboratory (CAL) located on the ISS is designed to help in this regard.

Recently, CAL scientists announced they had produced BECs from rubidium atoms, which were chilled to only 100 nanoKelvin, one-ten million of one Kelvin above absolute zero (-273 °C; -459 °F) — that’s around 3 Kelvin colder than ambient space.

At such low temperatures, the atoms have almost no motion. Free from the chaos of atomic vibration, scientists can now study fundamental behaviors and quantum characteristics that are nearly impossible to do at higher temperatures.

This was the first time that BECs have been created in orbit — one of the coldest places in the universe. These were first predicted in the 1920s by Albert Einstein and the Indian physicist Satyendra Bose but it wasn’t until 1995 that scientists were able to produce the necessary conditions for this extreme state of matter to occur, which involve cooling a gas with laser traps down to a fraction of a Kelvin.

At room temperature, atoms are incredibly fast and behave akin to billiard balls, bouncing off each other when they interact. As you lower the temperature more and more (remember temperature reflects atomic agitation), atoms and molecules start to move slower. Eventually, once you get to about 0,000001 degrees above absolute zero, atoms start behaving like waves, rather than particles as they ought to on the macroscopic scale. Essentially, the atoms behave like one super atom, acting in unison. This is why BECs are easier to study.

But creating a Bose-Einstein condensate is an extremely difficult process, one that earned three physicists the Nobel prize in 2001 for their groundbreaking work. Even with a pretty solid plan laid out on how to make the condensate, physicists have to painstakingly tweak their process until it’s just right.

The Cold Atom Laboratory (CAL) consists of two standardized containers. The larger container is called a “quad locker,” and the smaller container is called a “single locker.” The quad locker contains CAL’s physics package, or the compartment where CAL will produce clouds of ultra-cold atoms. Credit: NASA/JPL-Caltech/Tyler Winn.

On Earth, BEC experiments require equipment that would fill a whole room and constant monitoring from scientists. The CAL experiment is about the size of a small refrigerator and is remotely operated from Earth Orbiting Missions Operation Center at JPL. Day-to-day operations of CAL require no intervention from the astronauts aboard the station.

“It was a struggle and required significant effort to overcome all the hurdles necessary to produce the sophisticated facility that’s operating on the space station today,” said Robert Shotwell, the chief engineer of JPL’s astronomy and physics directorate, in a statement.

“Having a BEC experiment operating on the space station is a dream come true,” he added.

CAL scientists have their sights set on even lower temperatures, expecting to reach temperatures colder than any BEC experiment has recorded on Earth. They also plan on using other ultracold atoms such as two different isotopes of potassium.

Creating BECs in space is desirable because the effects of microgravity enable researchers to study individual BECs for 5 to 10 seconds at a time, with the ability to repeat measurements up to six hours per day. In contrast, BECs are far more unstable on Earth because gravity pulls the atoms, which offers a tiny window of a fraction of a second to study them.

“There is a globe-spanning team of scientists ready and excited to use this facility,” said Kamal Oudrhiri, JPL’s mission manager for CAL. “The diverse range of experiments they plan to perform means there are many techniques for manipulating and cooling the atoms that we need to adapt for microgravity, before we turn the instrument over to the principal investigators to begin science operations.” The science phase is expected to begin in early September and will last three years.

CAL is still in its commissioning phase, meaning that engineers are conducting tests to understand how CAL operates in microgravity. Its full scientific potential is, thus, far from having been reached.

Flu vs cold

How to spot the difference between a cold and the flu

Flu vs cold

Credit: Pixabay / Sambeet.

It’s common to dismiss a few sniffles and a cough as ‘nothing but a cold’ when, in fact, it might very well be a far more dreadful animal — influenza. It’s quite easy to mistake the two, too. Both are viral infections and symptoms often overlap. Sometimes, unless your doctor runs a test with a cotton swab from the back of your nose or throat, it can be very difficult to tell the two apart. Make no mistake though — the two types of viral infections can also be worlds apart, so much so that it could mean the difference between life and death. While the common cold is generally harmless, tens of thousands of people worldwide die each year from the flu.

Flu vs common cold

Flu symptoms include:

  • Fever or feeling feverish/chills
  • Cough
  • Sore throat
  • Runny or stuffy nose
  • Muscle or body aches
  • Headaches
  • Fatigue (tiredness)
  • Some people may have vomiting and diarrhea, though this is more common in children than adults.

Cold symptoms overlap greatly, but they’re typically milder than those of the flu. Another important difference in this regard is that people with colds are more likely to have a runny or stuffy nose.

Precisely because the symptoms of the two types of infection overlap so much, it can be very difficult if not impossible to diagnose one or the other based on symptoms alone. Instead, doctors rely on special tests performed within the first couple of days of illness to make the diagnosis. It’s a good idea to get tested within the first 48 hours of showing symptoms to minimize the risk of developing flu-related health complications.

The flu can lead to sinus and ear infections (moderate) or more serious complications such as pneumonia, inflammation of the heart (myocarditis), brain (encephalitis) or muscle (myositis, rhabdomyolysis) tissues, and multi-organ failure (for example, respiratory and kidney failure). Colds generally do not result in serious health problems.

Both the flu (influenza) and the common cold are viral infections of the upper respiratory tract but each is caused by different groups of viruses.  However, influenza can also infect the lungs and the joints, and can cause pneumonia, respiratory failure, and even death.

Credit: WebMD.

Credit: WebMD.

Colds come on gradually over a few days and are often milder than the flu. They usually get better in 7 to 10 days, although symptoms can last for up to 2 weeks.

Flu symptoms come on quickly — often within 1 to 3 days — and can be severe. Basically, if you wake up one morning suddenly feeling like you’ve been hit by a truck, it’s likely the flu. Symptoms usually last 1 to 2 weeks.

Influenza is responsible for body and head aches, whereas cold aches are much milder.

With a cold, you may or not feel tired. With the flu, however, tiredness and weakness are common.

Some people get a slight fever when struck by a cold, but most don’t. In contrast, any fever above 38 degrees Celsius (101 to 104 degrees Fahrenheit) is a sign of the flu, with children’s fevers tending to be higher.

Bottom line: fever, fatigue and muscle aches may be a sign of both types of viral infections, but if they are particularly bad it is likely to be the flu. Nasal symptoms are more likely to point to a cold. Flu comes on faster while, in contrast, a cold develops more gradually. Flu symptoms usually go away after a week; if they persist for up to two weeks, it’s probably a cold. There is a vaccine for the flu but none for the cold.

What is the common cold?

Common cold vs flu

Credit: Pixabay.

The common cold is an upper respiratory viral infection caused by an adenovirus, rhinovirus or coronavirus. More than 100 different viruses can cause the common cold, meaning there’s a lot of variability. For this reason, you’ll often hear that there’s no cure for the common cold nor is there any vaccination (a common cold vaccine might actually be in sight though). It’s true, however, that the rhinovirus is most often the one that makes people sneeze and sniffle.

Cold-causing viruses thrive in low humidity which is why they’re so common during winter months. These are airborne viruses which typically spread when someone sick sneezes or coughs. You can also get infected if you come in contact with a surface that a sick person also contacted and then touch your nose, mouth, or eyes.

Infected people are more contagious in the first two to four days after being exposed to the virus.

Common cold treatments

Over-the-counter medications, such as antihistamines, decongestants, acetaminophen, and NSAIDs, can relieve congestion, aches, and other cold symptoms. Drinking plenty of fluids to avoid dehydration is key.

However, there’s mixed evidence that remedies like zinc, vitamin C or echinacea prevent or relieve cold symptoms. A 2015 study found taking zinc lozenges could shorten the length of colds if taken within 24 hours of showing symptoms. Vitamin C doesn’t look like it prevents colds, but when taken regularly may lessen cold symptoms, according to a 2013 review. 

[ALSO READ] Why am I always cold? 

It’s always a good idea to read the active ingredients and warnings on all product labels. Many cough and cold medicines have the same ingredients, so you could accidentally overdose unless you’re careful.

Don’t ever take antibiotics for colds since this is a viral infection and not a bacterial infection. Viral infections typically go away seven to ten days after the first symptoms show. If symptoms persist after that, you might have bacteria like Strep or Haemophilus influenzae. These bacteria cause illnesses that are longer lasting.

What is the flu?

cold vs flu.

Credit: Pixabay.

The flu is also an upper respiratory viral infection. It’s caused by the influenza virus which is less variable and hence can actually be preventable. For instance, there are various flu vaccines.

Seasonal flu is caused by influenza A, B, and C, with A and B being the most common. New vaccines have to be developed every flu season though because active strains vary yearly. There are scientists, however, who are working on a universal flu vaccine. 

The flu spreads from to person to person just like the cold: by coming into contact with droplets spread by an infected person. Infected people are contagious starting 1 day before getting sick and up to 5 to 7 days after showing symptoms.

Unlike the common cold, the flu can easily develop into a more serious condition, particularly in the case of young children, older adults, pregnant women, and people with weakened immune systems.

Flu treatments

To shorten the duration of the flu infection and to prevent complications, your doctor may prescribe antiviral drugs such as oseltamivir or zanamivir. However, this kind of treatment only works within the first 48 hours of getting sick. If you’re too late, you can treat symptoms with over-the-counter pills like ibuprofen and acetaminophen. At the end of the day, though, there’s not much you can do other than resting and drinking plenty of fluids. If symptoms get worse, you ought to urgently see a doctor for any signs of complications such as pneumonia (severe sore throat, trouble breathing, chest pain, high and persistent fever).

The best way to prevent the flu is getting the flu shot, the best time to do this being in October (the start of flu season). Unfortunately, only 30 percent of 4,000 U.S. adults surveyed said they’d been inoculated this season.

To avoid contracting the viral infection, wash your hands often with soap and warm water. Most importantly, avoid touching your nose, eyes, and mouth. Stay away from people who have the flu or flu-like symptoms.

Regardless of whether you have a cold or the flu, the illness will usually go away on its own, but you should visit your doctor if your symptoms change or get worse.

Plutonian landscapes in twilight, under a hazy sky. Credit: NASA/JHU APL/SwR.

Layers of hydrocarbon haze could explain why Pluto’s so super-cold

Plutonian landscapes in twilight, under a hazy sky. Credit: NASA/JHU APL/SwR.

Plutonian landscapes in twilight, under a hazy sky. Credit: NASA/JHU APL/SwR.

Orbiting the sun over 40 times farther away than the Earth, it’s no wonder that Pluto is so incredibly cold. But when New Horizon made its historic flyby of the dwarf planet, NASA scientists were dumbfounded to find Pluto was even colder than expected — about 30 degrees Celsius (86 degrees Fahrenheit) colder. A new hypothesis suggests that a haze of solid hydrocarbons might be regulating Pluto’s temperature. If this hypothesis is confirmed, it would signify a new regime of planetary climate; something that’s never been witnessed before.

Pluto might not be a planet but at least it’s still cool

Researchers at the University of California, Santa Cruz, led by planetary scientist Xi Zhang, believe they’ve found the culprit for Pluto’s anonymously cold atmosphere. The New Horizons spacecraft revealed that the dwarf planet is surrounded by 20 or so layers of haze arranged like the skin of an onion. The haze is made of soot-like solid particles.

Scientists had known for decades that Pluto has an atmosphere and that it might be hazy, but it wasn’t until recently that they began to comprehend this stunningly complex atmospheric mechanism.

Zhang and colleagues devised a mathematical model that investigated whether or not the nanoparticles could be influencing Pluto’s atmospheric temperature. Indeed they can, the model suggested, whose results were almost a perfect match with New Horizon’s empirical observations.

The particles are no bigger than 150 nanometers in diameter and are thought to consist of hydrogen cyanide, acetylene, and other organic compounds, similar to the ones found around Saturn’s moon Titan. These particles might have a significant cooling effect on Pluto by absorbing infrared radiation, thereby reducing atmospheric temperature.

 “Basically, we needed a strong coolant to explain why Pluto is so cold,” Zhang told New Scientist. “We found that the abundant haze particles can strongly cool the atmosphere by re-emitting infrared radiation to space, a process not considered in previous theories.”

“In the infrared range of radiation, a slightly larger amount of energy is radiated back to space by the haze particles, cooling the atmosphere overall,” he added.

From six billion miles away, Earth-based detectors aren’t sensitive enough to identify Pluto’s near-infrared radiation, which could be one of the reasons why the haze wasn’t discovered sooner. Fortunately, the James Webb Space Telescope, which is scheduled to launch in 2019, will be equipped with the proper tools to investigate Pluto’s infrared radiation.

If the researchers’ hypothesis holds water, this would make Pluto the only solar system planetary body whose temperature isn’t principally controlled by gases.

Scientific reference: X Zhang, D F Strobel and H Imanaka, Nature, 2017, DOI: 10.1038/nature24465.


Why does hot water freezes faster than cold water? Enter the Mpemba effect

A Spanish team of researchers has developed a framework theory that could explain the Mpemba effect — the mysterious physical phenomenon that makes hot water freeze faster than cold water.


Image via Pixabay.

Preheated liquids freeze faster than cold ones. There’s some evidence that Aristotle first observed this effect in the 4th century AD, and it later piqued the curiosity of intellectual heavyweights such as Francis Bacon and René Descartes.

Hot ice cream

In 1960, the phenomenon took its first steps toward theory when Tanzanian student Erasto Mpemba observed that the hottest mixture of ice cream froze faster than the cold one during cookery class. Later, as a student at Mkwawa Secondary School in Iringa attending a physics lecture, he inquired about the causes of this phenomenon and was ridiculed by classmates and his teacher. However, the lecturer, Dr. Denis Osborne from the University College in Dar es Salaam, tested and confirmed Mpemba’s observations. The two published a paper in 1969 detailing the findings.

The strange effect later made it into both educational and science outlets, but its causes have been poorly understood until now. That’s why a team of Spanish researchers set out to determine why the seemingly counter-intuitive Mpemba effect exists.

“It is an effect that, historically, has not been addressed in a rigorous manner but merely as an anomaly and a didactic curiosity,” said Antonio Prados, paper co-author and researcher at the Universidad de Sevilla Department of Theoretical Physics. “From our perspective, it was important to study it in a system with the minimum ingredients to be able to control and understand its behavior.”

Certain “ingredients” have to come together for the effect to occur in a given system, the team reports. They studied the Mpemba effect in granular fluids, substances that contain hard inelastic spheres but behave as liquids. This environment was selected so that the team could simulate interactions between particles and “make analytical calculations to know how and when the Mpemba effect will occur,” said Antonio Lasanta, study co-author and a researcher at the UC3M, Universidad Carlos III de Madrid.

When these particles collide they shed energy. Since higher temperatures mean more motion at the molecular levels, the Mpemba effect will take place faster in warmer liquids. The study also confirmed the existence of a ‘reverse-Mpemba’ effect generated by the same interactions, where the coldest system will heat up faster than the hottest one. This reverse was first predicted about a year ago by Oren Raz, now at the Weizmann Institute in Israel, and Zhiyue Lu from the University of Chicago.

“The scenario that the effect will most easily occur in is when the velocities of the particles before heating or cooling have a specific disposition — for example, with a high dispersion around the mean value,” the athors add. This way, the evolution of the temperature of the fluid can be significantly affected if the state of the particles is prepared before the cooling, they explain.

A better understanding of the Mpemba effect won’t just advance our understanding of basic science but could have practical applications in the mid to long term. If the team’s theory is verified, it could lead the way to electronics that cool down faster, for example.

There’s still a ways to go until then, however. Like Raz and Lu’s paper before, the study garnered some criticism for the very simplified model used to study the effect, compared to water’s more complicated behavior. Taken together, however, the studies support each other and lend a great deal of confidence that such particular interactions fit in the wider mechanisms of the Mpemba effect.

At the same time, Mpemba himself first observed the effect in milk, which has many large particles suspended in water. The granular liquid models could also apply to water samples: large solute particles in impure water samples could contribute to the overall Mpemba effect.

The paper “When the Hotter Cools More Quickly: Mpemba Effect in Granular Fluids” has been published in the journal Physical Review Letters.


Why am I always cold? Science to the rescue


Credit: Pixabay.

If you shiver or feel like your hands and feet are like popsicles even though your friends say it’s a bit toasty outside, well that’s a red flag that signals your internal thermostat is a bit haywire. Doctors refer to such a sensation as cold intolerance.

Here are some of the reasons why you might always feel cold and some potential ways to fix the situation.

Not enough fat

Triglycerides, cholesterol, and other essential fatty acids — the fancy, scientific terms for fats that the body can’t produce on its own — store energy and serve to protect our organs. Fat also insulates the body so underweight people tend to feel colder than they should in normal conditions.

A low body mass index (BMI) is often the consequence of skimping on calories which can slow the metabolism thereby reducing body heat.

Underactive thyroid

Always feeling cold may be a telltale sign of hypothyroidism. An underactive thyroid gland means it can’t make enough thyroid hormone to keep the body running smoothly.

The butterfly-shaped endocrine gland’s job is to produce thyroid hormones into the blood from where they’re distributed to every tissue in the body. These hormones help the body use energy, stay warm and keep the brain, heart, muscles, and other organs in tip-top shape.

Besides feeling constantly cold when everybody else seems comfortable enough, other hypothyroidism symptoms include thinning hair, dry skin, and fatigue.

On average, about 4.5% of Americans have this condition with women affected more frequently than men.

You’re a woman

Due to their physiology, it’s more common for women to report feeling unusually cold. Women have relatively colder bodies, especially hands and feet, than men because estrogen reduces blood flow to the extremities.


Among its many vital roles, water helps regulate body temperature. When in adequate supply, water will trap heat and slowly release it keeping body temperature at a comfortable level. If you’re dehydrated, however, the body becomes more sensitive to temperature swings.

Water also essentially powers the metabolism. Having less water in the body than you ought to can slow down the metabolism cooling the body in the process.

Slow metabolism

Metabolism helps regulate the blood flow throughout your body. As outlined earlier, there are various factors that influence how fast we digest food and transport substances into and between cells.

People with a fast metabolism have an increased blow flow while, conversely, a slow metabolism results in sludgier blood flow.

Some people naturally have a slow metabolism but that doesn’t mean you can’t speed it up. Unless you have an underlying health issue like hypothyroidism, exercising can do wonders. People with more muscle mass tend to have a higher resting metabolism.

Low iron intake

When we think about nutrients, iron seldom comes to mind. You might be surprised to learn though that low iron is the most common nutritional deficiency in the U.S, particularly among women. Around 10% of American women are iron deficient according to the CDC and this comes with all sorts of problems, chronic coldness not the least.

Iron is an essential mineral for the human body whose main role is to ferry oxygen along the bloodstream. It’s the most important component of hemoglobin, the substance found in red blood cells that transport oxygen from the lungs to the rest of the body. Without healthy red blood cells, your body can’t get enough oxygen and a lack of red blood cells is called iron deficiency anemia. The immediate consequence is constantly feeling fatigued but also feeling cold.

How much iron you need each day depends on your age, gender, and overall health. So you should talk to your doctor about it.

Vitamin B12 deficiency

Besides iron, the vitamin B12 is also heavily involved in red blood cell production and oxygen transport. Without it, our bodies can’t produce red blood cells so not having enough leads to B12-deficiency anemia, or a low red blood cell count. Just like iron deficiency anemia, this lack of vitamin B12 results in chronic coldness.

The main source for acquiring B12 is diet. Aim to include lean meat, fish, and dairy into your meals.

Poor blood circulation

If your extremities — the hands and feet — feel like ice but the rest of the body seems fine then you might have a problem with enough blood reaching these parts of the body. This is usually a sign that your heart is not pumping blood properly and underlying heart disease might be at work. For instance, some arteries might be blocked.

Not enough sleep

According to a 2016 report, a third of all U.S. citizens aren’t getting enough shut eye. Doctors recommend adults sleep at least seven hours a night, ideally eight or nine. But about 35 percent said they usually got less than 7 hours of sleep a night. Frequently getting little sleep puts you at risk of developing obesity, diabetes, high blood pressure, heart disease, stroke and frequent mental distress, as well as brain fog.

Not getting enough quality sleep triggers the release of stress hormones and a reduction in the hypothalamus’ activity. The hypothalamus is a sort of control panel of the brain where the body’s temperature is regulated. And, you’ve guessed it, poor sleep can make you shiver.

These are just a couple of reasons that might lead some people to always feel cold. Usually, this isn’t much of nuisance but feeling shivers even if it’s warm outside can be a sign of an underlying illness. Talk to your doctor about it. 

Credit: Pixabay.

Vitamin D can protect against flu and cold, meta-analysis study confirms

Credit: Pixabay.

Credit: Pixabay.

A meta-analysis of 25 randomized controlled trials involving over 11,000 participants confirmed that vitamin D supplementation can stave off acute respiratory infections.

“Most people understand that vitamin D is critical for bone and muscle health,” said Carlos Camargo, MD, DrPH, of the Department of Emergency Medicine at Massachusetts General Hospital (MGH) and the study’s senior author. “Our analysis has also found that it helps the body fight acute respiratory infection, which is responsible for millions of deaths globally each year.”

This was a highly challenging work since many of these studies had different designs or participant qualifications. Some concluded that low Vitamin D levels were linked to a greater risk of developing an acute respiratory infection. Other clinical trials, on the other hand, which investigated the protective abilities of Vitamin D supplements reached opposing conclusions. Some found Vitamin D supplementation staves off infections while other found no conclusive evidence that this is the case.

The team led by Adrian Martineau from the Queen Mary University of London aggregated all of the data from these 25 trials by conducting an individual participant data meta-analysis. Typically, a meta-analysis averages data from all participants in each study. This was not the case. The researchers, instead, separated out the data from each individual participant to obtain a higher resolution analysis of the data from all these mammoth studies.

The conclusion is that daily or weekly supplementation had the greatest benefit for those individuals that had a Vitamin D deficiency, to begin with. Those with the lowest levels of Vitamin D (blood levels below 10 mg/dl) cut their risk of respiratory disease by half. All participants experience some beneficial effect from regular Vitamin D supplementation. Occasional high doses of vitamin D had no effect.

“Acute respiratory infections are responsible for millions of emergency department visits in the United States,” says Camargo, who is a professor of Emergency Medicine at Harvard Medical School. “These results could have a major impact on our health system and also support efforts to fortify foods with vitamin D, especially in populations with high levels of vitamin D deficiency.” The study was funded by a grant from the National Institute of Health Research (U.K.).

According to recommendations from the Institute of Medicine, most adults need about 600 IU (international units) of vitamin D per day while the elderly (over 70 years) are advised to intake 800 IUs per day.

We get our Vitamin from what we eat but also sourced from our own bodies as these produce Vitamin D when in contact with sunlight. A good Vitamin D-rich diet might include milk and other dairy products, orange juice, cereal, as well as sardines and other fish products which contain a high level of Vitamin D.

Since this is a meta-study, you should take the conclusion with caution. After all, some of the studies found that supplements don’t work. The standard multivitamin has about 400 IUs but if you’re already intaking 600 IUs, it’s not clear you need to take a supplement despite the current meta-analysis suggests ‘all participants can experience beneficial effects from supplementation.’

It’s best you visit your doctor who can check your Vitamin D levels. She will tell you the right course of action. Chances are you’re not deficient.

The findings appeared in The New England Journal of Medicine

NASA plans to build robots that explore frozen worlds from metallic glass so they don’t shatter

Metallic glass might be the key to exploring the frozen bits of the Universe, NASA believes. They’re working on a new class of this material that’s hard-wearing, strong, and should work just fine at very, very low temperatures.

Image credits NASA / JPL-Caltech.

Exploring space isn’t only hard work — it’s also incredibly cold. So cold in fact that the metal we make our crafts of just can’t take it. So rovers like the Curiosity, that poke around on frozen balls of space rock, require a constant flow of heated lubricant to keep working. This means we have to supply them with extra lubricant, delivery systems, and heating — all amounting to added mass and power drains.

The new class of metallic glass NASA’s been working on, called bulk metallic glass (BMG) could provide an alternative. The agency’s latest tests have shown that BMG gears can withstand strong torque and turn smoothly without lubricant even in environments as cold as -200 degrees Celsius (-328 degrees Fahrenheit).

“Being able to operate gears at the low temperature of icy moons, like Europa, is a potential game changer for scientists,” says NASA program manager R. Peter Dillon.

“Power no longer needs to be siphoned away from the science instruments for heating gearbox lubricant, which preserves precious battery power.”

A metallic glass is created by heating a liquid metal, to make sure its atoms are bouncing all over, then cooling it very quickly, by about 1,000 degrees Celsius (1,832 degrees Fahrenheit) per second. The process locks the atoms in place, preventing them from crystallizing in an orderly fashion. This random-distribution state is known as “vitreous” — the same state of matter that characterizes glass. The result is metal with some internal properties of a fluid, giving them much better flexibility and durability. The random structure also prevents most weak-spots in the metal from forming (as these usually these form around imperfections in the crystalline matrix).

While BMGs aren’t a new discovery, scientists have found it difficult to make hardware like robots and rovers out of it. NASA has shown that they can be used to fashion such components, however. They fashioned a part known as a strain wave gear (pictured above), which essentially keeps the artificial joints moving, from BMGs. Even better, they report that this approach is cheaper and less complicated than the conventional method.

“Mass producing strain wave gears using BMGs may have a major impact on the consumer robotics market,” says lead researcher Douglas Hofmann.

“This is especially true for humanoid robots, where gears in the joints can be very expensive but are required to prevent shaking arms. The performance at low temperatures for JPL spacecraft and rovers seems to be a happy added benefit.”

The findings “Optimizing Bulk Metallic Glasses for Robust, Highly Wear-Resistant Gears ” have been published in the journal Advanced Engineering Materials.

common cold

Did the vaccine for the common cold just had to include all rhinoviruses? Why didn’t you say so!

common cold

Credit: Flickr user Allan Foster

The common cold might not be cancer, but it’s sure is annoying. In the United States alone, doctors estimate one billion cases of the cold are recorded. For decades, scientists have been trying to come up with a vaccine that would neutralise the sore throat and running nose causing disease which is primarily triggered by rhinovirus infection.

The problem is that there are over 100 identified rhinoviruses and making a vaccine against one virus is rendered useless because there’s a whole armada out there. A team of researchers at the Emory University School of Medicine think they know how to make a common cold vaccine work, though. Their solution is simple: make a vaccine with all the rhinoviruses you can carry.

The first common cold vaccine was made in the 1960s. Back then, researchers showed it was possible to vaccinate people and prevent them from getting sick when put in contact with the virus. It only worked against a single strand of rhinovirus, though — the one they also placed in the vaccine. The sheer number of rhinoviruses circulating all around us has made a lot of scientists abandon hope that a common cold vaccine is feasible.

[panel style=”panel-warning” title=”How to reduce the risk of getting a cold” footer=”source: CDC.gov”]- Wash your hands often with soap and water. f soap and water are not available, use an alcohol-based hand sanitizer. Viruses that cause colds can live on your hands, and regular handwashing can help protect you from getting sick.
– Avoid touching your eyes, nose, and mouth with unwashed hands
– Stay away from people who are sick [/panel]

Emory University researchers, however, applied a simple straightforward solution to a seemingly complicated problem. They made a mixture of 25 types of inactivated rhinovirus, then injected them in 25 mice. They also made a mixture of 50 types of such viruses and injected them in rhesus macaques.

In response to the vaccine, both mice and monkeys created antibodies which later proved to prevent the virus from infecting human cells cultured in a dish.

“We think that creating a vaccine for the common cold can be reduced to technical challenges related to manufacturing,” says Martin Moore, associate professor of pediatrics at Emory University School of Medicine.

“It’s surprising that nobody tried such a simple solution over the last 50 years. We just took 50 types of rhinovirus and mixed them together into our vaccine, and made sure we had enough of each one,” Moore says. “If we make a vaccine with 50 or 100 variants, it’s the same amount of total protein in a single dose of vaccine. The variants are like a bunch of slightly different Christmas ornaments, not really like 50 totally different vaccines mixed.”

The researchers, however, could not test to see whether the animals themselves got sick because there isn’t any reliable animal model for rhinoviruses. Instead, the next thing the researchers plan to do is start a clinical trial with human subjects, something which is deemed feasible considering the non-pathological nature of the common cold. And if the results are confirmed in humans, then millions of sore throats will be made much happier in those cold winter nights.

Findings appeared in Nature Communications.



Why your brain doesn’t catch a cold


Illustration: Michael Helfenbein

In most of the world, winter long ground to a halt to make way for more harmonious seasons. Still, these are still tense times for your health, as one day can be sunny, the other murky and cold. A lot of people get snuffed and catch a cold. While you’re tucked inside your sheets, blowing your nose and cursing the day you caught that wretched cold, comfort yourself with the thought at least it wasn’t your brain that caught the cold.

I know what you must be thinking; what kind of comforting thought is that? A new study by Yale School of Medicine researchers, which appeared in the  Journal of Virology, shows that when a virus is detected in the nose a long-distance signaling system can activate anti-viral defenses in distant parts of the brain.

“When you think about it, it is more crucial to health of the brain more than any other organ to have robust mechanisms to combat viruses,” said Anthony van den Pol, professor of neurosurgery and lead author of the study. “Brain cells don’t turn over. Once they are dead they are dead.”

The Yale researchers note that  most signals in the brain travel about 20 nanometers across a synapse but when the olfactory bulb detects a viral invader immune system defenses are activated nearly a million times farther away even in uninfected areas of the brain. Research conducted in mice also shows this response is independent of the peripheral immune system.