Category: Lecture Page 14 of 20

Peter Singer Explains "Effective Altruism"

On October 30, 2013

In Environment/Sustainability, Field Research, Global Health, Lecture, Students

By Clara Colombatto

In a recent conversation over Skype, renowned ethicist Peter Singer encouraged a group of Duke students to “think from the point of view of the universe” and use their education to alleviate suffering in low-income countries.

Singer, the Ira W. DeCamp Professor of Bioethics at Princeton University, has published numerous books on ethics and animal rights and spoke to Duke students about effective altruism on October 22.

Peter Singer talks to Duke Students on a Skype conference.

Peter Singer talks to Duke students via Skype.

Altruism is not about ethical pureness and spiritual nobility, Singer said; rather, he believes individuals should focus on the ultimate result of their actions. This is effective altruism–helping others while making sure one’s efforts are well directed and the best use of time and resources.

As an example, Singer pointed out that $40,000 could train one guide dog for a blind individual, but that same amount could prevent blindness for 100 people in a low-income country.

Research shows that not all charities are created equally–some are a hundred or even a thousand times more effective than others. Give Well is an agency that assesses the impact of charities, and of hundreds companies screened, the agency recommends only three: Against Malaria Foundation (AMF), which provides insecticide-treated nets in sub-Saharan Africa; GiveDirectly, which distributes cash to extremely poor individuals in Kenya; and Schistosomiasis Control Initiative (SCI), which assists African governments with treatment of neglected tropical diseases.

THINK promotes effective altruism organizing discussion and support meetups around the world

THINK advocates for effective altruism.

The Skype conversation was organized by the Duke chapter of The High Impact Network (THINK), a group that promotes effective altriusm. THINK organizes meet-up groups at universities and cities around the world to help members increase their positive impact in the world and create networks for support and collaboration.

The Duke chapter was founded by juniors Andrea Tan, Sheetal Hegde and Lainey Williams. The group unites students from different backgrounds–from public policy to neuroscience for discussion and service, including a partnership with Durham Urban Ministries to support student outreach and service.

Humans, Whales and Taylor Swift

By Ashley Mooney

On October 25, 2013

In Animals, Biology, Cancer, Climate/Global Change, Field Research, Lecture

by Ashley Mooney

The similarities between chromium workers and whales are greater than one might think.

Environmental toxicology researcher John Wise has been studying the connection between exposure to pollutants and the onset of cancer in humans. To understand the link, he said one must take into account all species, especially whales. Wise spoke at Duke Oct. 25 at the Inaugural Duke Distinguished Lecture in Cancer and the Environment.

Chromium crystals. Courtesy of Wikimedia Commons.

“For environmental health for me, [the Earth] is the big picture,” Wise said. “This is home and we only have one, so we have to think pretty hard about environmental health.”

Wise studies the effect of pollutants—specifically forms of chromium—on genetic material in humans, marine mammals, and birds and other marine species. While the standard approach to environmental toxicology research is to conduct epidemiology studies on highly exposed populations and then expose animals to high doses of the toxin, Wise has adopted a new method of study.

“We don’t really know what high-dose exposures mean on a day-to-day basis,” he said.

To understand the relationship between chromium exposure and the onset of cancer, Wise looks at the personal factors that affect one’s health, such as an individual’s body and genome, lifestyle, daily exposures and what kind of environment one lives in.

“We need to know mechanism: how does a normal cell become a tumor cell?” he said. “For a long time that is where the field has been hung up, trying to identify the ultimate carcinogen.”

Most forms of naturally occurring chromium are not toxic. Man-made hexavalent chromium, however, has been shown to cause lung cancer in those who are regularly or heavily exposed to it. Prolonged exposure induces an altered chromosome number and structure, as well as DNA double strand breaks.

Chronic exposure to chromium also causes a shift from more a protective form of DNA repair called homologous recombination to a less stable and error-prone pathway called non-homologous end joining. This means that cells will have permanently deficient repair mechanisms.

Wise applies his research in the context of ocean health, namely how chromium exposure might harm whale DNA.

Most ocean pollutants, including the toxic form of chromium, are in the ocean sediment. As the ocean becomes increasingly more acidic, the sediment breaks off and poses a growing threat to marine species.

Wise measured chromium levels in baleen whale skin, and found that Atlantic seaboard species—the northern right whale, fin whale and humpback whale—have 16- to 41-fold higher levels than other baleen whales. Toothed whales living in the Gulf of Mexico exhibited levels that resembled those found in chromium workers who died of lung cancer.

A humpback whale surfacing for air. Courtesy of: Protected Resouces Division, Southwest Fisheries Science Center, La Jolla, California. swfsc.nmfs.noaa.gov/PRD/.

In whales, chromium can lead to DNA damage and reproductive suppression.

“There’s only 400 [northern right whales] left in existence,” Wise said. “If you only have 400 animals, you need every single one of them [to be able to reproduce].”

Wise said he hopes his research will encourage people to think more about habitat degradation and climate change, and how they affect all species.

taylor-conor-sailing-team, courtesy of popdust.com

Wise (back right) photographed with his lab and Conor Kennedy (back left). Courtesy of popdust.com.

His lab, however, has recently gained publicity not for its research, but for the public figures that have worked with it. Conor Kennedy, a member of the influential Kennedy family, worked with Wise’s team and Ocean Alliance last year. At the time he was dating pop-star Taylor Swift.

“[He was], like any other high school student, constantly texting on his phone and I would do what I did with my kids and the other students, and say ‘put the girl down, we have to go to work,’ not knowing the girl was Taylor Swift,” Wise said. “It really hit home that we were traveling in very different circles.”

Tigers may still come roaring back

By Ashley Mooney

On October 22, 2013

In Animals, Field Research, Lecture

by Ashley Mooney

Although tigers have been threatened with near extinction for decades and some extinction narratives in the 1990s predicted they’d disappear by 2000, they might actually be making a comeback.

Indian conservationist Ullas Karanth thinks tigers can be saved, and the key to saving them is optimism.

“Conservation is about being optimistic, but rationally optimistic,” said Karanth, the Wildlife Conservation Society’s director of science for Asia and founding director for the Centre for Wildlife Studies in India. He spoke at Duke Oct. 22 for the Ferguson Family Distinguished Lectureship in the Environment and Society.

At one point, tigers occupied about 30 present-day countries, but that range has shrunk by 93 percent to a mere 115,000 square miles of forest, Karanth said.

Courtesy of Wikimedia Commons.

As India continues to rise through developmental pathways, Karanth said it is crucial to preserve land for all animals, not just tigers. India is about a third of the size of the United States, but has four times as many people. As India’s economy continues to grow, urban areas continue to creep into and to destroy wildlife habitats.

“When I say tiger conversation, I mean all this,” he said referencing all of the animals that coexist in the tiger habitat. “In India, the idea that you can have space for nature and that other creatures need space is accepted. It provides a positive platform on which you can build more knowledge.”

Wanting to save tigers isn’t enough, he said, adding that conservation must be science driven.

Since Karanth began studying tigers in 1986, his program has grown from a small tiger study to a “pretty substantial intervention.” He identifies and studies animals using photographic capture-recapture sampling, in which he places cameras throughout the tigers’ range and occasionally captures and tracks them using collars.

Ullas Karanth in the field. Courtesy of Wikimedia Commons.

“It started as a small project and took time,” Karanth said. “You can’t be Usain Bolt and do conservation. It’s a marathon.”

Throughout this marathon, conservationists must also utilize human networks to preserve a species. Karanth uses his relationships with a number of people within the government system, religious leaders and the media to promote tiger conservation. He also writes books and articles in the local languages to reach rural populations.

“We don’t have a lot of time for experiments or romantic ideas, we need to make sure this species survives,” Karanth said. “Solutions that are greatly rewarding [in other countries] just don’t work in this context.”

By reaching out to as wide of an audience as possible, Karanth said he was optimistic about the future for the tigers.

“I truly believe that we can at sometime have over 50,000 tigers in India again,” he said.

Collaboration, Mentorship Lead to Clinical Science Successes

By Prachiti Dalvi

On October 21, 2013

In Biomedical Engineering, Lecture, Medicine

By Prachiti Dalvi

The School of Medicine held the third Clinical Science Day on Friday, October 18th during Duke Medical Alumni Weekend in the Great Hall of the Trent Semans Center. The half-day event brings together faculty, alumni, and students to discuss the cutting edge clinical research taking place in labs across Duke’s campus. The day started out with residents and fellows from a variety of clinical departments participating in a poster competition, followed by fifteen minute presentation by several key clinicians on campus.

Osteoarthritis causes a wearing away of the articular cartilage. (Image credit: http://images.rheumatology.org/viewphoto.php?albumId=77030&imageId=2897682)

Dr. Louis DeFrate from the Department of Orthopedic Surgery is interested in finding a new way to overcome osteoarthritis, a disease that has the potential to affect everyone as they age and is expensive to treat. Obesity increases the risk of osteoarthritis significantly by increasing strain on cartilage in between bones, or articular cartilage. DeFrate is focused on understanding how motion affects how the joints work. “There is very little data on how obesity affects cartilage deformation,” said DeFrate. This information is key to treating osteoarthritis effectively.

Dr. Kimberly Blackwell, who was on TIME’s 2013 list of the 100 most influential people in the world, discussed her research on HER2+ breast cancer tumors. These tumors, affecting 20% of breast cancer patients, are aggressive in coming back and reduce survival rate. The treatment Blackwell and her team have developed consists of an antibody specific to the tumor, loaded with an anticancer toxin. In general, cancer treatments focus on “killing the cancer more than you kill the patient,” says Blackwell. However, this new treatment is able to increase survival rates without many of the unpleasant side effects of other cancer treatments such as chemotherapy. Blackwell has been able to get two cancer-fighting drugs approved by the Federal Drug Administration.

Duke surgeons implanting the bioengineered vein. (Picture credit: http://www.newsobserver.com/2013/06/07/2944111/duke-surgeon-conducts-first-us.html)

Vascular surgeon Dr. Jeffrey Lawson discussed his success with implanting a bioengineered blood vessel into the arm of a patient with end-stage kidney disease. The technology designed by Lawson and colleagues involves cultivating donated human cells in a tubular apparatus. Any antibodies that may trigger an immune response are removed and then implanted into the patient. The first implantation took place in Poland in December. The first surgery in the United States took place in June at Duke. Lawson worked closely with Laura Niklason, MD, PhD, a former Duke faculty member who is now at Yale. Lawson and Niklason have worked together to found Humacyte, a spin-off company that makes these bioengineered vessels commercially available. Initially, researchers are interested in implanting these veins in kidney dialysis patients and seeing if they are beneficial. However, ultimately, researchers want to make readily available and durable grafts for heart bypass surgeries to treat blocked blood vessels in the limbs.

All researchers echoed the sentiment that the culture of collaboration and mentorship at Duke is unparalleled.

World Suicide Prevention Day sheds light on youth suicide

By Ashley Mooney

On September 10, 2013

In Behavior/Psychology, Field Research, Global Health, Lecture, Medicine

By Ashley Mooney

Although suicide is one of the leading causes of death in youth world wide, prevention research is often undervalued, said Monica Swahn, associate vice president for research at Georgia State University, who visited Duke this week.

In her talk to global health advocates and medical students on Monday, Sept. 9, she presented her data on social factors that contribute to youth suicide attempts in Kamapala, Uganda. Swahn noted that suicide research is often focused on deaths, which most countries generally are good at tracking. Her interest, however, was in suicide ideation—the ideas, thoughts and feelings that precede suicide planning and attempts, since twenty times as many people think about suicide as actually succeed at it.

Courtesy of Wikimedia Commons

“We talk about why are people at risk for suicidal behaviors and suicidal thoughts, and typically we come from a psychological perspective, but there are also biological factors and social-environmental factors,” Swahn said.

Approximately one million people commit suicide every year, and about 20 million attempt suicide. In the United States, suicide is the third leading cause of death for youth ages 10 to 24. Swahn’s study population, however, focused on “slum youth” living in Uganda.

“I still struggle with the term slum youth,” she said. “When we talk about slum youth, it’s one of those difficult conventions of how many street youth are there in the world, well there’s no way to know exactly. Estimates range from 100-300 million worldwide.”

Swahn’s data show that 31 percent of “slum youth” living in Kampala report suicide ideation. Of those who think often of suicide, many also reported either that both of their parents had died or neglected them due to alcohol abuse. Girls were also more likely to report suicide ideation than boys.

For the 23 percent of Ugandan youth who reported actually planning a suicide attempt, the majority expressed that they suffered from parental neglect due to alcohol, sadness and the feeling of expecting to die early.

“Suicide is a very complex problem not unlike other global health problems that we study, in that there are also differences across countries and cultures, but those haven’t been studied consistently,” Swahn said.

Studies of suicide prevention in Uganda will become increasingly important, Swahn said, with the population continuing to expand past the country’s capacity to meet its people’s healthcare needs. Right now, Uganda has a population of approximately 37 million, and Swahn noted that the country is expected to experience a five-fold increase in its population by 2050.

Swahn showed a sign that hangs outside of the clinic where she collected her survey data. (Photo by Ashley Mooney)

Beyond the challenges of a rapidly increasing population, Uganda suffers from the highest level of alcohol consumption per capita in the world, contributing to the neglect due to alcohol that many youth thinking of suicide cited in the surveys.

Even though Swahn has identified some of the correlates to suicide in the slum youth, knowing what the problem is remains only a small part of the battle.

“By the time we do a cross-sectional survey like this, it’s almost too late,” she said. “The question is, how do we broaden the access to care?”

'Street Cred' Key to Leadership, Coach K says

By Ashley Yeager

On May 20, 2013

In Business/Economics, Lecture, Medicine

By Ashley Yeager

Former politician Ron Paul speaks at the 2013 Feagin Leadership Forum. Credit: Ashley Yeager, Duke.

Former presidential candidate Ron Paul, an MD from Duke Medical School, speaks at the 2013 Feagin Leadership Forum. Credit: Ashley Yeager, Duke.

Credibility is key for becoming a leader, both basketball coach Mike Krzyzewski and former politician Ron Paul told a group of Duke medical school students on May 18.

The two spoke as part of the Duke Sports Medicine Feagin Leadership Forum, a weekend meeting focused on ethical leadership.

“Ethical leadership takes courage, integrity and character,” Krzyzewski said. “You can see ethics and talk about ethics. But to do it, you’ve got to feel it.”

He, along with Paul and the other speakers and panelists, told the audience anecdotes where they had to choose to be ethical despite the decision not being the easiest or the most favorable among their peers.

Joanne Kurtzberg, a specialist working with children’s blood disorders, explained her difficult decision to send a patient to Europe for treatment using umbilical cord blood. The procedure was life-saving but had not yet been approved by the FDA in the U.S.

The decision and Kurtzberg’s pioneering effort in umbilical cord banking and treatments earned her what Krzyzewski called “street cred.” He said those looking to lead should be in constant search of credibility from their peers because it is one of the most important ways to show a person is willing to what is hard and difficult but the right thing to do.

While the audience was a mix of military, business and medical leaders, Krzyzewski tailored his speech mainly to the 2013 Feagin Medical Scholars, 16 medical school students who receive additional training in moral and ethical leadership, public speaking and other skills to make them well-rounded doctors.

Krzyzewski said the program is unique because it combines “two of the best jobs in the world,” being a doctor and being a leader. “Getting into medicine is huge,” he said, and becoming a leader “makes you part of something bigger.”

This program, he added, can take ethical leadership in medicine to a level no one has reached before, making it the gold standard, not only in the U.S., but also worldwide.

Success now lies in the scholars developing their “street cred.”

The Phishing Market Beyond the Internet

By Ashley Mooney

On April 29, 2013

In Behavior/Psychology, Business/Economics, Lecture, Neuroscience

By Ashley Mooney

Most people have heard of phishing scams on Internet, in which a person is tricked into giving up their money or identity by a clever ruse.

Temptations like this are found throughout all of capitalist society, says George Akerlof, 2001 Nobel Laureate in Economic Sciences. He discussed ideas from his upcoming book, “Phishing for Phools” wth a Duke audience on April 25 to kick off “Decision Making Across the Disciplines,” a two-day symposium sponsored by the Duke Center for Interdisciplinary Decision Sciences.

Akerloff studies connections between individual’s decision biases and larger economic phenomena.

George Akerlof won the Nobel Prize in Economic Sciences in 2001 for his research on economic decision making. (Image courtesy of Wikimedia Commons)

“Standard economics assumes that the people are smart, they may not know everything but they can be smart,” he said. “But there may be only one way in which you can be smart, but there are many, many ways in which you can be stupid.”

Akerlof, who is also Koshland Professor of Economics at the University of California, Berkeley, developed his idea of phishing for phools from his paper, “The Market for ‘Lemons,’” which secured his Nobel nod.

“A fool with an f is a stupid or silly person, but it’s perfectly possible to make an error when… making a perfectly intelligent decision,” he said. “Somebody who makes a mistake is a phool with a ph.”

Although markets have the ability to maximize wealth, Akerlof said it is a double-edged sword.

“Free markets open us up to be phools. They open us up to those who seek to influence us to do what they want, but it’s not necessarily good for our sake,” he said. “We live in a world where some 5 billion adults can phish us for being a phool. We’ve intentionally opened ourselves up to such exploitation because of obvious advantages, but then we must also think about the other side.”

Markets, Akerlof noted, aim for three weak spots: emotional weaknesses, cognitive weaknesses and ignorance due to blocked channels of information.

Phishing is common on the internet, but occurs throughout the market. (Image courtesy of Wikimedia Commons)

When people are aware of phishing, it has relatively little effect. But when one doesn’t know about a phish, it can have a major impact. He proposed that obesity, product misinformation and the recent economic recession were all caused by phishing for phools.

“In the United States, the goal of almost every businessman is to get you to spend your money,” he said. “Life in capitalist economy is a continual temptation.”

Akerlof said according to economics textbooks, people decide on their demand by budgeting spending and then choosing the things that will maximize their happiness. But most people, he added, are not honest with themselves and as a consequence do not engage in rational budgeting.

“A very significant fraction of consumers are worried about how they’re going to make ends meet,” Akerlof said. “Almost 50 percent of people probably could not come up with $2,000 in a month for unforeseen situations.”

The only way to prevent phishing is to know about it, and to make informed decisions with that knowledge.

“Phishing for phools… creates bad equilibrium, especially if we don’t know about phishing for phools, we think that markets are totally benign,” Akerlof said.

UPDATE – June 28, 2013

The Economics Department has posted a YouTube video of Ackerlof’s entire talk.

[youtube http://www.youtube.com/watch?v=U85MKnS8i8U?rel=0]

Everyone Makes Mistakes

By Pranali Dalvi

On April 24, 2013

In Behavior/Psychology, Lecture, Medicine

By Pranali Dalvi

Dr. Brian Goldman, Credit: nsb.com

“Every important thing that I have ever learned since the day I was born has come from a mistake,” said Dr. Brian Goldman on April 17 during the Duke Colloquium.

Goldman is a renowned thinker and leader on issues of medical ethics and medical error. He has had great success in two high-adrenaline fields: broadcasting and medicine.

Not only is he a practicing emergency physician at Mount Sinai Hospital in Toronto but he also hosts an award-winning radio show White Coat, Black Art where he discusses the Canadian healthcare system. His bold TED Talk ‘Doctors Make Mistakes: Can We Talk about That?’ has over 700,000 hits.

Goldman’s life-altering mistake happened during a 2-month elective in neurology at Johns Hopkins. By medical school, he was a veteran insomniac, often waking up early — except for the one morning he was supposed to deliver grand rounds. That morning, he woke up at 10 AM, the exact moment when he was supposed to be presenting rounds in the neurology conference room at the hospital across the street.

“This mistake was a dramatic enough gesture to make me pay attention. I don’t wish a medical error on anybody, and I don’t wish the misfortune that happens to patients and families that are directly involved. But sometimes it’s a moment like that which redirects you and gets you into thinking about what you need to do with the rest of your life,” Goldman said.

The mistake made him reconsider neurology.

Credit: thestudentceo.com

Too often people have one of two worldviews of failure. The first inspires you to do better – if you fall down seven times, get up eight. The other shows success and failure as completely different paths.

“What we need is for health professionals and the public to realize that mistakes are inevitable with humans,” Goldman said.

What does error look like in medicine?

Radiology mistakes including X-ray and CT misinterpretations, miscalculating medication dosages, and hospital-acquired infections due to poor hand washing practices are human errors in medicine. All potentially catastrophic yet hard to detect.

Why do these errors happen?

The vast majority of health professionals are some of the most caring and compassionate individuals. Why do they mess up? Emphasis on quantity over quality, stress, miscommunication and messy handwriting are just a few of the many reasons.

“I spoke to a pharmacist who said that if you simply add 30 seconds of look-up time to every medicine dispensed at the hospital pharmacy, he’d have to hire 2 more full-time pharmacists. If you don’t have that kind of money, this is the sort of institutional cutting of corners that we have to go through to make ends meet,” Goldman said.

Credit: The Adventures of Pam & Frank Blog

Errors also result from the organization of the system. Residents often don’t go home despite 80-hour week regulations. They fear that no one else knows their patient as well as they do. Patient safety is also compromised as you increase the number of handovers due to duty hour regulations.

Goldman insists on the development of technologies to prevent mistakes, reducing responsibilities to allow increased productivity and fostering a loving and respectful environment for doctors to discuss their errors.

How can we aim for success in a field where failure is so effortless?

The Duke Colloquium, the brainchild of Dr. Andrew Hwang, is a university-wide initiative to pull the humanities into the professions. The event bring forward-thinking visiting scholars to Duke’s campus to inspire students, faculty, and the broader Duke community to become more socially conscious professionals.

Chocolate's crisp crack comes from chemistry

By Ashley Yeager

On March 28, 2013

In Chemistry, Faculty, Lecture, Physics, Science Communication & Education, Students, Visualization

By Ashley Yeager

This is the final post in a four-part, monthly series that gives readers recipes to try in their kitchens and learn a little chemistry and physics along the way. Read the first post here and the second one here and the third one here.

This bunny must have been made from quality chocolate. His ears are already gone. Credit: Waponi, Flickr.

When you snap off and savor the ears of a chocolate bunny this Sunday, say a quick thanks to science.

“The essence of science is to make good chocolate,” said Patrick Charbonneau, a professor of chemistry and physics at Duke.

He explained that cocoa butter, one of the main ingredients in chocolate, can harden into six different types of crystals. All six types are made of the same molecules. But, at the microscopic level, the types have distinct molecular arrangements, which lead to differences in the crystals that form.

“The problem with chocolate is that only two of these types have good texture when eaten,” Charbonneau told students in the Chemistry and Physics of Cooking.

He teaches the freshman seminar with chef Justine de Valicourt and chemistry graduate students Mary Jane Simpson and Keely Glass.

During class, students looked at and tasted chocolate containing only the good-tasting crystal types and some that also contained the less favorable ones. The first had that signature sheen and snap of quality chocolate and melted evenly when left on the tongue. The latter pieces were dull, melted with the slightest touch and left a sandy texture on the tongue.

The demonstration showed that the different types of chocolate crystals melt at different temperatures. By carefully controlling the chocolate as it cools, chocolate-makers can create mixtures of only the favorable crystal types.

The process, called tempering, takes chocolate through a series of heating and cooling steps. The initial cooling step forms many of the chocolate crystal types, including the dull, unfavorable ones. Warming the mixture a little — to about 31°C (87°F) — melts the unfavorable crystals but not the best-tasting ones.

As the mixture cools again, the remaining, favorable crystals “seed” the chocolate so that good-tasting crystals form preferentially throughout, ensuring good chocolate structure and taste.

Students got a chance to test the science in lab later that evening, and judging by the number of mouths (and faces) covered with chocolate, it’s safe to say the science was successful.

If you’re looking to try it out — or save a poor bunny’s ears — here’s the recipe.

Tempering chocolate:

Materials:
1 small, microwave safe bowl
1 big bowl
1 spatula
2 scraper spatulas
1 chocolate mold
parchment paper
cooking thermometer

Ingredients:
250 g Dark Chocolate or 250 g Milk Chocolate (about 1 1/3 cups)

Filling:
60g white chocolate (about 1/4 cup)
60g yogurt (a little less than 1/4 cup)

Instructions:

1. Place milk or dark chocolate in the small bowl.
2. Heat the bowl in 30-second intervals in a microwave (stirring after each) until the chocolate is melted. Note: The milk chocolate should take about 1.5 minutes and the dark chocolate about 2 minutes to melt.
3. Once heated, pour half the liquid chocolate onto a clean marble or stone counter. The chocolate puddle should be the size of a medium pancake. (Note: If there is not stone or marble surface, another technique is to melt less chocolate and then add good tempered chocolate in it to lower the temperature.)
4. Spread the pancake portion out in ribbons using the scraper spatula. Bring the chocolate back together into a mound repeatedly for 5 minutes, until it starts to solidify.
5. Put the chocolate back in the original heating bowl. Adding the cooler chocolate will cool the rest of the liquid to the right temperature.
6. Mix the cold and hot chocolate.
7. Check the temperature of the chocolate. (Dark: 31-32°C/88-89.5°F; Milk: 29-30°C/84-86°F).
8. Dip the parchment paper in the mixture of the “hot” and “cold” chocolate. If it cools on the parchment paper and is uniform and shiny, then it’s ready.
9. Pour chocolate into mold.
10. To make stuffed chocolate candies, flip the mold to empty excess chocolate.
11. Turn it back, scrap the excess of chocolate off the surface. Let the thin layer of chocolate in the mold crystallize.
11. Melt white chocolate. Mix it with yogurt. Cool to room temperature.
12. Add filling to 2/3 of the mold cavities, and then pour more tempered chocolate on top.
13. Level the chocolate with a scraper and scrape off excess.
14. Let it rest for few minutes at 20°C (68°F) or put it in the fridge.
15. Pop candies from mold and enjoy.

Making sense of smells

By Prachiti Dalvi

On March 18, 2013

In Biology, Lecture, Medicine, Science Communication & Education

By Prachiti Dalvi

Nobel Laureate Dr. Richard Axel, who visited Duke on March 14, 2013.

“A good scientist has to have a nose for which field to work in,” cancer researcher Bernard Weinstein once told his mentee Dr. Richard Axel.

It was a saying Axel took quite literally.

He and Linda Buck won the 2004 Nobel Prize in Physiology or Medicine for discovering the cell receptors that run our sensory system for olfaction, or the sense of smell.

Axel first stepped into the research world when he took a job as a glass washer to support himself during his undergraduate years at Columbia University. After a few broken test tubes and dirty beakers, he was fired as a glass washer and, instead, rehired to do research. He went on to publish three papers as an undergraduate, including one where he was senior author.

In 1979, he earned his medical degree from Johns Hopkins University. He then returned to Columbia, and in 1977 he, along with Michael Wigler and Saul Silverstein, discovered a way to insert foreign DNA into a host cell to produce particular proteins.

The finding grew into to the field of molecular cloning and earned Axel a spot in the National Academy of Sciences at 37.

Axel moved on to study how the brain represents the external world. This is a central issue in philosophy, psychology and neuroscience. But unlike, vision and touch, which have at least two dimensions in the external world, information about odors has no dimensionality at all.

So, how is smell represented in the various smell centers of the brain? Axel explained what scientists know about the representations during a March 14 lecture sponsored by the Ruth K. Broad Foundation and the Chancellor’s Lecture Series.

Pathway of odor perception (courtesy of nobelprize.org)

The process starts in the nose, where different kinds of smell-sensing cells line the nasal cavity. Each type of smell-sensing cell expresses only one of about 1400 odor-receptor genes. The cells expressing a given gene are randomly distributed through the nasal tissue and send projections back through the skull into the olfactory bulb.

This bulb is essentially first relay station for sensing smell in the brain. The incoming information gets consolidated in a part of the bulb called the glomerulus. There a given odor receptor activates nerve fibers called glomeruli. They send signals to higher brain regions, which then create a topographic map of incoming odors.

This topographic map is similar, or conserved, in all individuals of a species, Axel said.

His lab at Columbia is now focused on understanding how the sense of smell is established during development, how it may change over time and how certain smells can elicit specific thoughts and behaviors.