Science

Researchers Get Frustrated Magnets to Show Hall Effect for the First Time

April 6, 2015 By Lilian Nwa 1 Comment

In condensed matter physics as described in a Wikipedia article on the subject, “frustration” is a phenomenon in which atoms stick to specific, non-trivial positions or where inter-atomic forces favoring different structures conflict, and this “frustration” creates complicated structures or behaviors.

Frustrated magnets are a class of materials that similarly develop novel characteristics given their “discontentment,” in particular these magnets should be magnetic at low temperature but are not. In an experiment conducted by researchers at Princeton University, the authors made a novel discovery about these materials, which according to researchers “may help clarify the mechanism of high-temperature superconductivity, the frictionless transmission of electricity.

In planning experiments, the authors hoped to determine if frustrated magnets exhibit the Hall Effect, which occurs when electric currents carried by charged particles in a conductor accumulate on one side when subjected to a magnetic field. Given that frustrated magnets are non-magnetic at low temperatures, understanding if these materials can indeed produce the Hall Effect is of significant importance for future advances in computing and the creation of devices such as quantum computers.

According to one of the authors N. Phuan Ong, Eugene Higgins Professor of Physics at Princeton, “To talk about the Hall Effect for neutral particles is an oxymoron, a crazy idea.” Still, Ong and his colleague, Princeton’s Russell Wellman Moore, Professor of Chemistry, as well as their graduate students Max Hirschberger and Jason Krizan were able to observe the Hall effect in a non-magnetic material.

In order to do so, the research team studied a class of magnets known as pyrochlores, which should have orderly “spins” at very low temperatures, but have been found to have spins that point in random directions, thus rendering them with magnetic frustration properties. To grow the pyrochlore crystals, Krizan used material from terbium oxide and titanium oxide to form a powder that could be used to feed crystal growth. This powder was suspended in a chamber filled with pure oxygen and subjected to high temperatures.

To determine if the frustrated crystals shows the Hall Effect, Hirshberged then attached gold electrodes to the end of each slab and used microheaters to transfer a hear current analogous to an electric current through the materials, while applying a magnetic field perpendicular to the current. It was at this time that the Hall effect was observed in the non-magnetic, pyrochlore crystals.

As Ong said in a statement, “All of us were very surprised because we work and play in the classical, non-quantum world. Quantum behavior can seem very strange, and this is one example where something that shouldn’t happen is in reality there. It really exists.”

(Photo courtesy of Jason Krizan)

Limiting Global Warming to 2 Degrees Celsius Is “Utterly Inadequate”

March 29, 2015 By Lilian Nwa 6 Comments

Limiting global warming to 2 degrees is utterly inadequate

In October of last year, scientists David G. Victor and Charles F. Kennel wrote in an article for the journal Nature that for nearly a decade, international diplomacy has set a goal of “stopping global warming at 2 degrees celsius above pre-industrial levels.” However, the authors strongly criticized this goal, stating that, “..it has allowed some governments to pretend that they are taking serious action to mitigate global warming, when in reality they have achieved almost nothing.” As well, the authors proclaimed that scientifically there are much better ways to measure how human activities have impacted the average global surface temperature beyond the 2 degree celsius standard.

Now, a recent article by Petra Tschakert of Penn State University in University Park has also denounced the target as being “utterly inadequate” and wants to revise the target to 1.5° C. In an article published in the journal Climate Change Responses, she warns that the lower limit is necessary to protect coral reefs, prevent sea level rises and maintain the presence of ice during Arctic summers.

Tschakert is not the only expert who has warned that a decreased temperature increase target is necessary. In fact, during a recent meeting of the Intergovernmental Panel on Climate Change’s Fifth Assessment Report, most of the panel’s members seemed to agree. However, whether or not this new goal is achievable remains to be seen. Indeed, some researchers already believe this goal is impossible as emissions have gone from bad to worse and will likely result in a 3° C temperature increase by 2100.

However, in a new book titled “Climate Shock: The Economic Consequences of a Hotter Planet” by Gernot Wagner of the Environmental Defense Fund and Martin L. Weitzman at Harvard, the authors seem to suggest that there might be an alternative. In a proposal they call the Copenhagen Theory of Climate change, The New York Times reports the authors suggest “we should be asking people to volunteer to save our climate by taking small, individual actions.”

The motivation behind the name of their proposal (Copenhagen) refers to the ability of the Danish government to convince half of its residents to commute to work by bicycle each day. As The New York Times reports, “A half-century ago, the city’s inhabitants were becoming almost as reliant on cars as people anywhere else. But after the oil crisis of the 1970’s…many Copenhagen residents made a personal commitment to ride bicycles…out of moral principle, even if that was inconvenient for them.”

If people in other parts of the developed and developing world could be convinced to make such a commitment, this “polycentric approach for coping with climate change” could yield real results. But, as the Times warns, the world is “diverse and complicated” and in order to combat climate change and global warming, we will need to establish a global, “concrete framework” with consequences for those who choose not to play by the rules.

(Photo courtesy of Andreas Kambanis)

Super Pi Day is a Once in a Century Event

March 14, 2015 By Lilian Nwa 4 Comments

For math enthusiasts, March 14th, or Pi Day, provides the perfect excuse to make pies and celebrate the mathematical constant, pi. Pi describes the circumference of a circle and is often written as 3.14, though computers have calculated pi up to 10 trillion digits.

Unlike other Pi Days, some have called this year “Super Pi Day” or “Pi Day of the Century” because Saturday’s date (3/14/15) reads exactly like the first five digits of pi (3.1415). Even more, at 9:26:53 a.m. and p.m., the date and times together will represent the first 10 digits of the constant.

The L.A. Times reports that humans have known about the constant pi for nearly 4,000 years, but then the ancient Babylonians, who first started thinking about the number, had estimated that the value of pi was approximately three.

Our annual celebration of this number is a “more recent invention,” which is often credited to Larry Shaw, who organized the first celebration of the constant in 1988 for the San Francisco Exploratorium where he worked as a physicist.

To celebrate, people often eat pies or discuss the significance of the number. As well, Wikipedia describes competitions held at schools to determine which student can recall pi to the “highest number of decimal places.” Interestingly, the Massachusetts Institute of Technology (MIT), one of the premiere institutions for higher education, mails its application decisions early enough so that applicants can receive the judgements on Pi Day.

Other celebrations are more inclusive. For example, the Jet Propulsion Laboratory (JPL) has begun a Pi Day Challenge, “inviting the public to think like space mission scientists and use pi to determine how to map a distant planet or estimate the volume of an alien ocean.” Teachers and their students have been asked to tweet their answers to this question with the hashtag #PiDay.

In a blog post for his company, Stephen Wolfram goes further than discussions of “pi” and space to discuss the science of pi and its importance. Why is pi so famous? Wolfram explains that the constant “appears in a remarkable range of mathematical settings–including many that don’t seem to have anything to do with circles.” Indeed, one of his most interesting points explained that as individuals construct formulas at random and begin to perform “traditional mathematical operations” like summations, integrals, etc., pi is often a definite result in these operations.

Wolfram also mentions that the next Pi Day of the century will be in 2115. So, for now, enjoy Saturday’s Pi Day as an excuse to indulge in some sweets and perhaps marvel at the order and randomness of mathematics.

(Photo courtesy of medea material)

Female Menopausal Killer Whales Are Group Leaders, Help in Group Survival

March 7, 2015 By Lilian Nwa 1 Comment

Research studies have previously shown that postmenopausal women have a “decidedly beneficial effect on the reproductive success of [their] children and the survival of [their] grandchildren.” This effect, known as the grandmother hypothesis, has been used to better understand, in evolutionary terms, why women live past their childbearing age.

Now, in a recent study published in the journal Current Biology, the authors attempt to explain why menopausal females increase the reproductive success of their descendants. Interestingly, they do so by studying another species where menopausal females also live long: orcas, known colloquially as “killer whales.” According to Discovery News, like humans, female orcas breed between the ages of 12-40, but can survive much longer, even into their 90s.

In order to arrive at their conclusion, the authors collected information on orcas over a 35-year time period, making observations on 102 individuals. As described by Discovery News, the information collected included the obvious birth and death dates, but also more complicated information about the genetic and social relationships amongst the animals.

In analyzing the dataset, the authors discovered that postmenopausal females behave as “repositories of ecological knowledge,” and do so by “leading groups when the orcas are moving together in salmon foraging grounds.” The leadership role of these females becomes especially important during years when salmon becomes more difficult to find. In fact, salmon shortages are an important contributing factor to death rates among the orcas, so the role these females play is especially significant.

As co-author Lauren Brent said in a statement, “Our results show for the first time that…value gained from the wisdom of elders can help explain why female killer whales and humans continue to live long after they have stopped reproducing.”

The authors also found that “females are more likely to lead their sons compared to their daughters.” In explaining this result, co-author Daniel Franks at the University of York explained that sons have higher reproductive potential and mate outside the group, so their offspring do not compete with “resources within the mother’s matriline.”

In a statement about the research, Croft mentioned previous studies in human beings that have suggested menopause is only an “artifact of modern medicine and improved living conditions.” The work of Croft and her colleagues, however, suggest that menopausal women also share information that may be essential for the group’s survival. In today’s modern society filled with iPhones, Wikipedia and Google at our fingertips, perhaps there is still much to be learned from older individuals who often have interesting tales to tell about life and from whom we can learn a lot.

(Photo courtesy of doriana del sarto)

Over 1 Billion Teenagers and Young Adults at Risk for Hearing Loss

March 1, 2015 By Lilian Nwa 1 Comment

1 billion teen and young adults at risk of hearing loss

According to the Center for Hearing and Communication, hearing loss affects approximately 38 million people in the United States. By age 65, one of every three people have some degree of hearing loss, making it a major public health issue and the third most common physical condition after arthritis and heart disease.

Now, according to research conducted by the World Health Organization, 1.1 billion teenagers and young adults are at risk of experiencing hearing loss. Specifically, half of individuals aged 12 to 35-years-old expose their ears to “unsafe” sound levels when using audio devices and about 40 percent expose their ears to “potentially damaging” sound levels at entertainment venues.

As Dr. Etienne Krug, WHO Director for the Department for Management of Noncommunicable Diseases, Disability, Violence and Injury Prevention told ABC, “As they go about their daily lives doing what they enjoy, more and more young people are placing themselves at risk of hearing loss.” She also warns that once an individual experiences hearing loss, “It won’t come back.”

The National Institute of Deafness and Communication Disorders carefully explains the science behind noise-induced hearing loss on their website. Essentially, hearing loss occurs when there is damage to the hair cells, sensory cells that rest on top of the basilar membrane and are sensitive to sound waves.

When sound enters the cochlea, hair cells move causing the microscopic hair-like projections (sterocilia) sitting on top of the hair cells to bend. This bending motion then results in the opening of protein channels that allow chemicals to enter the hair cell, which generates an electrical signal that is sent to the brain and interpreted as sound. Thus, the death of these cells means that some (or all) sound waves cannot be transmitted to the brain via the movement of the hair cells and sterocilia (hence the loss of hearing).

In order to prevent hearing loss, WHO has suggested that people limit the use of headphones to one hour a day and also recommends that individuals avoid spending more than 8 hours in a workplace with 85 (or more) decibels of sound (bars and sporting events typically have around 100 decibels of noise).

Though some hearing loss can be temporary, it is important to note that hearing loss can be experienced due to a sudden, loud noise in addition to repeated, prolonged exposure to certain noises. If a person is experiencing hearing loss, it’s best for him or her to contact a physician to determine the extent of damage, if any.

(Photo courtesy of flattop341)

Climate Change Denier Wei-Hock Soon Took Over $1 Million from the Oil Industry

February 22, 2015 By Lilian Nwa 2 Comments

Leading climate change denier Wei-Hock Soon has taken over 1 million dollars from the oil industry

There is an ongoing debate about how humans are affecting the global climate and subsequently, what governments and policy makers should do to stem the effects of climate change. According to Wikipedia, no scientific body disagrees with the view that global surface temperatures have increased primarily due to human-induced emissions of greenhouse gases, and as such, there should be political pressure to prevent continued changes.

However, there is a small group of scientists who disagree with this view, and altogether, the issue has become one of political debate, with many Republican deniers. To prevent the undue (and unscientific) influence of outside organizations and groups, supporters and deniers of global warming have been questioned about their sources of funding and recently, one of the leading climate change deniers was revealed to have received more than $1.2 million from the fossil fuel industry over the last decade.

The denier, scientist Wei-Hock (Willie) Soon of the Harvard-Smithsonian Center for Astrophysics has argued, “Variations in the sun’s energy rather than greenhouse gas emissions are behind global warming.” With his clearly anti-global warming stance, Dr. Soon has appeared on a number of conservative news programs and conferences, and has also testified before Congress.

Though this discovery does not necessarily mean he falsified scientific reports or that his corporate funders influenced his scientific beliefs, it does cast a significant shadow on his integrity and reliability as a researcher. According to the Times, Dr. Soon published 11 pages since 2008 concerning his theory and omitted the required disclosure in each one. In at least eight, the Times reports that “he appears to have violated ethical guidelines of the journals that published his work.”

As if this were not enough, documents obtained from Dr. Soon show correspondence between the researcher and his corporate funders in which he described his papers as “‘deliverables’ that he completed in exchange for money.” Previously, Dr. Soon has also reacted angrily when questioned about his funding sources, and though he has acknowledged some corporate ties, he has not been upfront or clear about his sources.

Historian of science Naomi Oreskes, also at Harvard University, has weighed in on this case and its broader implications for scientific debate. She told the Times, “The whole doubt-mongering strategy relies on creating the impression of scientific debate…Willie Soon is playing a role in a certain kind of political theater.”

Perhaps then those who deny climate change are less interested in science than the “political theater” of the relentless back-and-forth between themselves and those they disagree with. Like parents who refuse to vaccinate their children, the views of these people say less about their scientific knowledge and more about their inability to trust the government or any ‘outside’ source of knowledge.

(Photo courtesy of Mark van Laere)