Tag Archives: harvard

HAMR.

Tiny, new-generation robot can walk on land, water, or swim — while being downright adorable

One of the tiniest robots to come out of Harvard’s laboratories shows that being small can be a huge advantage.

HAMR.

HAMR, the tiny bot.
Image modified after Y. Chen et al., 2018, Nature Comm.

Fitfully christened the ‘Harvard Ambulatory Microrobot’ (HAMR), the device does exactly what it says on the tin — it’s from Harvard, it moves, it’s tiny, and it’s a robot. But don’t let its modest appearance deceive you, for HAMR will do a lot of things its beefier brethren can’t.

The robot can walk on land, walk underwater, or walk on water without any time constraints. The team behind HAMR hope their tiny creation will open up new possibilities for bots, paving their way towards new environments.

It’s HAMR time

HAMR really is tiny. It weighs an intimidating 1.65 grams (0.05 oz) — about as much as a paper clip — and can carry an additional 1.44 grams of payload while retaining its ability to float. The bot draws on a new generation of multifunctional foot pads to carry it across watery surfaces. These pads use surface tension induced buoyancy to keep the bot afloat — just like those tiny bugs that zip across water surfaces.

But just floating isn’t very useful — it’s much more useful to float towards something. The team has the bot covered in that regard. They equipped HAMR with four pairs of asymmetric flaps and programmed it with custom-designed swimming gaits to help it paddle the water surface and move around. The robot’s swimming patterns resemble those of a diving beetle, the team adds, allowing it to both advance and turn.

HAMR movement.

Robot swimming and turning on the water surface. B) graph tracks its speed going forward over time, while C) and D) track the speed of its turning motions.
Image credits Y. Chen et al., 2018, Nature Comm.

Moving on the surface requires little energy and saves HAMR the hassle of avoiding obstacles. But should the need arise, it can also apply a voltage to its foot-pads. The process, known as electrowetting, reduces the contact angle between a material and the water surface under an applied voltage, the team writes. This change makes it easier for an object to break the water surface and sink.

A coat of Parylene keeps it from shorting under water.

“This robot nicely illustrates some of the challenges and opportunities with small-scale robots,” said senior author Robert Wood.

“Shrinking brings opportunities for increased mobility — such as walking on the surface of water — but also challenges since the forces that we take for granted at larger scales can start to dominate at the size of an insect.”

Once below, HAMR moves around using the same gait it employs on dry land. The bot is just as mobile underwater, but emerging back to try land does pose a few problems. The surface tension of a body of water is relatively immense since the bot is so tiny. When trying to emerge, surface tension applies a force roughly twice the robot’s weight down on HAMR. The team also notes that this process dramatically increases friction on the robot’s hind legs, destabilizing and potentially damaging it.

To overcome this issue, they made HAMR’s diminutive transmission more sturdy and installed soft pads on its front legs to increase payload capacity and redistribute friction on inclined planes. All these changes mean that HAMR can currently break surface tension and emerge from a body of water — provided it can find a ‘modest incline’ to climb out on.

“HAMR’s size is key to its performance,” said co-author Neel Doshi. “If it were much bigger, it would be challenging to support the robot with surface tension and if it were much smaller, the robot might not be able to generate enough force to break it.”

“This research demonstrates that microrobotics can leverage small-scale physics — in this case surface tension — to perform functions and capabilities that are challenging for larger robots,” adds first author Kevin Chen.

While HAMR doesn’t have any real-life applications so far, it’s a great platform to showcase the advantages (and shortcomings) of tiny robots. The team will keep refining their design. Next on their list is improving HARM’s ability to move around and making it return to land even without a ramp — the team is currently coquetting with gecko-inspired pads or some sort of jumping mechanism for the task, although they may settle on a different solution.

But perhaps most importantly, HAMR is cute as a button. Judging from this video Harvard created back in January, if they ever make a pet version of the tiny little robot, I’m getting one. The video showcases an older version of HAMR, which lacks the padded feet and waterproof coating.

The paper “Controllable water surface to underwater transition through electrowetting in a hybrid terrestrial-aquatic microrobot” has been published in the journal Nature Communication.

Moderate Alcohol Consumption Could Actually Help Your Heart

A new study conducted by Harvard scientists concluded that moderate consumption of alcohol (moderate!) can lead to lower risk of heart failure. The study, which was conducted on over 14,000 men and women aged 45-64 found that a small drink every day is associated with a 20 percent lower risk of men developing heart failure and 16 percent reduced risk for women.

Image via Substance.com

Alcohol is generally regarded as unhealthy. However, alcohol has its benefits; in the Mediterranean diet, moderate consumption of red wine is indicated, and the Mediterranean diet is one of the best for the heart. Previous studies have also found that moderate alcohol consumption is associated with better memory later in life. This study found that alcohol itself can be good for the heart.

“The findings suggest that drinking alcohol in moderation does not contribute to an increased risk of heart failure and may even be protective,” said Scott Solomon, professor of medicine at Harvard Medical School and senior physician at Brigham and Women’s Hospital in Boston.

A cocktail a day keeps the doctor away

The team defines “a drink” as one small (125ml) glass of wine, just over half a pint or a third of a litre of beer and less than one shot of liquor such as whisky or vodka. The participants in the study were divided into six categories:

  • abstainers
  • former drinkers, current abstainers
  • people who drink 1-7 drinks a week
  • people who drink 7-14 drinks a week
  • people who drink 14-21 drinks a week
  • people who drink over 21 drinks a week

During the study, almost 20 percent (1,271 men and 1,237 women) of participants developed heart failure. Out of those, the lowest rate of heart failures occurred in those drinking up to seven drinks per week and interestingly enough, the highest occurrence was in former drinkers. Men who drank between 1 and  7 drinks a week had a 20% reduced risk of developing heart failure compared to abstainers, while in the women, that risk was reduced by 14%.

A pint of beer a day might help your heart. Image via Cache Blog.

It’s quite possibly that the reason why former drinkers showed the highest rates of heart failure is that they had a medical reason to quite drinking in the first place. The sex difference seems statistically relevant, but it’s not yet clear why this happens.

“There are a number of different mechanisms by which the effects of alcohol on the heart may differ by sex,” write the researchers in their study. “Women have a higher proportion of body fat and absorb and metabolize alcohol differently than men, attaining higher blood alcohol concentrations for a given amount of alcohol consumed.”

The study was not raw, and scientists controlled, as much as possible, for other elements which may impact the results. They compensated for age, diabetes, high blood pressure, heart disease or heart attacks, body mass index, cholesterol levels, physical activity, education and smoking,

“We did adjust our results to take account, as far as possible, for a variety of other lifestyle factors that could affect a person’s risk,” Solomon explained.

However, as we pointed out several times, correlation does not imply causation. The fact that moderate drinkers show a lower chance of heart failure does not necessarily mean that it’s the alcohol doing the good.

“It is important to bear in mind that our study shows there is an association between drinking moderate amounts of alcohol and a lower risk of heart failure but this does not necessarily mean that moderate alcohol consumption causes the lowered risk, although we did adjust our results to take account, as far as possible, for a variety of other lifestyle factors that could affect a person’s risk.”

Journal Reference:

  1. A. Goncalves, B. Claggett, P. S. Jhund, W. Rosamond, A. Deswal, D. Aguilar, A. M. Shah, S. Cheng, S. D. Solomon. Alcohol consumption and risk of heart failure: the Atherosclerosis Risk in Communities Study. European Heart Journal, 2015; DOI: 10.1093/eurheartj/ehu514

Quantum materials may replace silicon in transistor construction

In today’s world, silicon has few materials which actually contest its status as the king of electronics. However, that may change in the not so distant future. A group of Harvard researchers have used a quantum material called correlated oxide to make better, more efficient transistors.

Transistors and quantum materials.

A common transistor. Wiki Commons.

The strategy for building better and more advanced processors is pretty simple – even rudimentary: just cram in as many transistors and circuits as possible into smaller and smaller surfaces. But sooner or later, this approach will meet its limit – there’s only so many things you can put in a limited space. Also, when you get to a small enough scale, strange quantum effects start to happen, interfering with the processing. This is why we already have to start thinking about what materials will replace and improve silicon – and this is where this study steps in.

The results (which the team describes as “colossal”) emerged in a very unlikely place – a laboratory usually designed to studying fuel cells—the kind that run on methane or hydrogen.

“Traditional silicon transistors have fundamental scaling limitations,” saysAssociate Professor of Materials Science at the Harvard School of Engineering and Applied Sciences (SEAS). “If you shrink them beyond a certain minimum feature size, they don’t quite behave as they should.”

However, for all their limitations, silicon transistors are very efficient – with an on/off ratio of at least 104 required for practical use.

“It’s a pretty high bar to cross,” Ramanathan explains, adding that until now, experiments using correlated oxides have produced changes of only about a factor of 10, or 100 at most, near room temperature.

But their results are better than that – better than many transistors used today too. Their on/off ratio was 105, competing with the best today’s silicon has to offer.

“Our orbital transistor could really push the frontiers of this field and say, you know what? This is a material that can challenge silicon,” Ramanathan says.

Using correlated oxides is not a novel idea – they have been studied for intensively for a few years, but the field is still in its infancy. Correlated oxides are quantum materials – this means that quantum-mechanical interactions have a dominant influence over the material properties, not only at a small scale, but also at a large scale.

“If you have two electrons in adjacent orbitals, and the orbitals are not completely filled, in a traditional material the electrons can move from one orbital to another. But in the correlated oxides, the electrons repulse each other so much that they cannot move,” Ramanathan explains. “The occupancy of the orbitals and the ability of electrons to move in the crystal are very closely tied together—or ‘correlated.’ Fundamentally, that’s what dictates whether the material behaves as an insulator or a metal.”

They are among a select group of alternatives for silicone transistors, including biological transistors, graphene transistors, or even single atom transistors.

A new kind of planet found – the mega-Earth – suggest higher possibilities of locating habitable worlds

A rocky world weighing 17 more than the Earth was discovered, and because it’s not only way much bigger than the previously discovered ‘super-Earths’, but also all solids, the scientists called it ‘mega-Earth’. Until this recent discovery, scientists believed that a world of such dimensions would be physically impossible to form, because of the thickness that would absorb the hydrogen gas as it grew and become a Jupiter-like gas giant.

ILLUSTRATION BY DAVID A. AGUILAR, CFA

 

Xavier Dumusque, the Harvard-Smithsonian Center for Astrophysics (CfA) representative, who led the data analysis and made the discovery, declared that they were very surprised to have identified such a formation. Kepler-10c was previously known to have a diameter of approximately 18,000 miles (2.3 times bigger than the Earth), which would have placed the planet into the mini-Neptunes category, characterized by thick gaseous envelopes.

The newly discovered mega-Earth circles a sun-like star every 45 days, according to the researchers. Its location is approximately 560 light-years from the Earth, in the Draco constellation.  A 3-Earth-mass ‘lava world’, Kepler-10b is also contained by the solar system, whose main characteristic is the uncommonly fast 20-hour orbit. While it’s hard for the scientific world to explain the formation of such large, rocky planet, the latest observational studies suggest that’s highly possible for other planets to have similar characteristics. Accordingly, astronomer Lars A. Buchhave managed to find, recently, a correlation between the period of a planet (representing the time it takes to orbit its star) and the size at which the transition from rocky to gaseous is made, theory which implies that there are more mega-Earths yet to be discovered, along with the extension of the planet hunters and their data towards longer-period orbits.

The CfA researcher Dimitar Sasselov, director of the Harvard Origins of Life Initiative, declared that ‘This is the Godzilla of Earths! But unlike the movie monster, Kepler-10c has positive implications for life.’  Kepler -10c was discovered by NASA’s spacecraft, Kepler. The satellite uses the transit method in order to disclose planets, searching for dimming stars whenever planets pass in front of it. After the receptive process, the dimming represents the key information by whose interpretation the astronomers can measure the planet’s physical size or even its diameter. What Kepler can’t inform is whether the planets found are solid or gassy.

But the discovery of the mega-Earth is only merely significant in itself, as it’s far more important what it connotes: given that the Kepler-10 system is approximately 11 billion years old, it means that the planet formed only 3 billion years after the Big Bang, discovery which has significant implications on both the history of the universe and the possibility of life on other planets.

The explanation of this is purely deductive as the scientists see it: it is believed that the early universe only contained hydrogen and helium, since heavier elements, which are necessary in order to form rocky planets, were only created during the first generations of stars. It was when they exploded that these materials were scattered through space and only after that moment could they have been incorporated into later generations of stars and planets. The above mentioned process is believed to have taken billions of years. The fact that this planet exists in a rocky form at these dimensions means that the universe was able to form such huge rockets even during the time when heavy elements were scarce.The immediate conclusion of the scientists is that

if you can make rockets you can make life!Dimitar Sasselo.

At its turn, this implies that if we shouldn’t necessarily rule out the much older stars when searching for Earth-like planets given that they could host rocky Earths as well, this discovery implies that the chance of locating potentially habitable worlds is significantly larger.

Top Universities grade inflation? Most common grade at Harvard is A, median is A-

The most common grade at Harvard is A, and the median grade is A-, Dean of Undergraduate Education Jay M. Harris explained, raising fears about top American Universities artificially inflating their grades or employing softer grading standards. The information was delivered at the monthly meeting of the Faculty of Arts and Sciences, as a response to government professor Harvey C. Mansfield:

“A little bird has told me that the most frequently given grade at Harvard College right now is an A-,” Mansfield said during the meeting’s question period. “If this is true or nearly true, it represents a failure on the part of this faculty and its leadership to maintain our academic standards.”

Image source.

After what appeared to be a shamed hesitation, Harris gave the response:

“I can answer the question, if you want me to.” Harris said. “The median grade in Harvard College is indeed an A-. The most frequently awarded grade in Harvard College is actually a straight A.”

In a later email response, Mansfield wrote that he was “not surprised but rather further depressed” by Harris’s answer.

“Nor was I surprised at the embarrassed silence in the whole room and especially at the polished table (as I call it),” Mansfield added, referencing the table at the front of the room where top administrators sit. “The present grading practice is indefensible.”

Grade inflation

So is this a Harvard thing, or is it a national grade inflation issue? Well most top Universities don’t make their average grades public, and I could only find information on Yale and Princeton. Last spring, Yale’s ad hoc committee on grading found that 62 percent of Yale College grades between 2010 and 2012 were in the A-range. Their committee is yet to take any concrete measures, but it’s good to hear that at least they are aware of the problem. Meanwhile, Princeton has totally restructured their grading system. Princeton’s grading policy has set a common grading standard for the University, under which As (A+, A, A-) shall account for less than 35% of the grades given in undergraduate courses and less than 55% of the grades given in junior and senior independent work. The Faculty has agreed that grades in the A range signify work that is exceptional (A+), outstanding (A) or excellent (A-).

[ALSO READ] Managers lose track of the big picture, only focus on grades and performance, not context

Image Source.

Ivy league college students graded more than they deserve

However, even with limited information, it seems fairly intuitive that Harvard isn’t an isolated case – since the mid 1960s, US college grades have risen significantly, from an average of 2.5 to an average of 3.2 – something which doesn’t seen possible to explain just by improving student performances. However, Harvard seems more prone to this issue than other top universities. In 2001, FAS’s Educational Policy Committee labeled grade inflation “a serious problem” at the College after a report in the Boston Globe labeled the College’s grading practices “the laughing stock of the Ivy League.”

Still, Princeton aside, I have seen no discussions of grade deflation in Ivy League Universities.

buckliball

Toy-inspired “Buckliball” paves the way towards a new class of engineering structures

buckliball

Scientist at MIT and Harvard University teamed up to figure out what would be the simplest 3-D structure capable of collapsing and morphing due to instability. Their inspiration came after the scientists came across a popular toy, spherical in shape and fitted with movable parts and hinges, which allows it to easily dimple in size reversibly. Based on this toy, the researchers created the  “buckliball,” a hollow, spherical object made of soft rubber with no movable parts, which can turn into a smaller ball, 46 percent its original size.

Its name was attributed since it resembles a buckyball, and because it makes us of the instability phenomenon known as buckling, most often in practice an effect which is sought to be avoided.

“In civil engineering, buckling is commonly associated with failure that must be avoided. For example, one typically wants to calculate the buckling criterion for columns and apply an additional safety factor, to ensure that a building stands, says  Pedro Reis, the Esther and Harold E. Edgerton Assistant Professor of Civil and Environmental Engineering and Mechanical Engineering at MIT. “We are trying to change this paradigm by turning failure into functionality in soft mechanical structures. For us, the buckliball is the first such object, but there will be many others.”

The buckliball has 24 special dimples arranged in a specific pattern for optimal buckling, which was induced by researchers by sucking the air of the buckliball with a syringe. When its thing ligaments buckle, the thicker ligaments rows undergo a series of movements the researchers refer to as a “cooperative buckling cascade.” Some of these thick ligaments rotate clockwise, while other counterclockwise, but interestingly they all come together harmoniously. Thus, the buckliball morphs from a circular structure into a rhombicuboctahedron at about half of its original size.


Morphable structures which make us of predictable buckling such as the buckyball have a range of application where they might be effectively used, be it on the micro or macro scale – a football stadium with an easily collapsible buckly dome; tiny drug-delivery capsules or soft movable joints requiring no mechanical pieces.

“The buckliball not only opens avenues for the design of foldable structures over a wide range of length scales, but may also be used as a building block for creating new materials with unusual properties, capable of dramatic contraction in all directions,” says Katia Bertoldi, an assistant professor in applied mechanics at Harvard.

The findings were published in the journal Proceedings of the National Academy of Sciences.

[source MIT]

Photosynthesis – not just for plants anymore

cyano

As any fourth grader will tell you, photosynthesis is (in layman terms), the process through which plants (and bacteria, algae, etc) get the sugars and other organic compounds they need using energy from sunlight. However, during last week’s synthetic biology conference in Boston, a biologist from Harvard took things to a whole new level, presenting a new and exciting idea: he injected a symbiotic cyanobacteria responsible for almost 50 percent of Earth’s photosynthesis into a fish.

He chose a zebra fish for this, because they are clear, which makes them excellent candidates for this kind of research. So they injected bacteria into fish embryos, and waited. The results ? Nothing special happened – which is amazing ! Both the fish and the bacteria grew normally, as you can see in the video here.

The bacteria didn’t generate enough energy to sustain the fish on its own, but it provided a well received nutritional boost. Pamela Silver, a biologist from Harvard, is leading a team that is working on methods to increase the cyanobacteria production. So does that mean that we’ll have photosinthetic animals, or even humans in the near future? Absolutely not. But when dealing with these kind of ideas, the near future means nothing; and in the more distant future? Why not…