SciByte

Image caption: Close-up view of Curiosity drill bit penetrating John Klein outcrop

Curiosity can drill to a depth of about 2 inches (5 cm) into rocks

Ultimately a powdered and sieved sample about half an aspirin tablet in size will be delivered to the SAM and CheMin analytical labs on the rover deck.

This image

was taken with the camera positioned about 4 inches (10 centimeters) off the ground

about 3 inches (7.7 centimeters) wide. The length of the gray divot cut by the drill bit is about two-thirds of an inch (1.7 centimeters)

Another preparatory test, called "mini drill," will precede the full drilling

The mini drill test will use both the rotary and percussive actions of the drill to generate a ring of rock powder around a hole

This will allow for evaluation of the material to see if it behaves as a dry powder suitable for processing by the rover's sample handling mechanisms

a gray plastic vessel, as long as a baseball bat, filled with water from Lake Whillans, half a mile below.

The bottle was hurried into a 40-foot cargo container outfitted as a laboratory on skis

Some of the lake water was squirted into bottles of media in order to grow whatever microbes might inhabit the lake

cultures could require weeks to produce results

When lake water was viewed under a microscope, cells were seen: their tiny bodies glowed green in response to DNA-sensitive dye. It was the first evidence of life in an Antarctic subglacial lake.

(A Russian team has reported that two types of bacteria were found in water from subglacial Lake Vostok, but DNA sequences matched those of bacteria that are known to live inside kerosene—causing the scientists to conclude that those bacteria came from kerosene drilling fluid used to bore the hole, and not from Lake Vostok itself

In order to conclusively demonstrate that Lake Whillans harbors life, the researchers will need to complete more time-consuming experiments showing that the cells actually grow

dead cells can sometimes show up under a microscope with DNA-sensitive

weeks or months will pass before it is known whether these cells represent known types of microbes, or something never seen before

t a couple of things seem likely. Most of those microbes probably subsist by chewing on rocks. And despite being sealed beneath 2,600 feet of ice, they probably have a steady supply of oxygen.

oxygen comes from water melting off the base of the ice sheet—maybe a few penny thicknesses of ice per year

When you melt ice, you’re liberating the air bubbles [trapped in that ice

That’s 20 percent oxygen

, lake bacteria could live on commonly occurring pyrite minerals that contain iron and sulfur

would obtain energy by using oxygen to essentially “burn” that iron and sulfur (analogous to the way that animals use oxygen to slowly burn sugars and fats).

The half mile of glacial ice sitting atop Lake Whillans is quite pure—derived from snow that fell onto Antarctica thousands of years ago.

contains only one-hundredth the level of dissolved minerals that are seen in a clear mountain creek, or in tap water from a typical city

a sensor lowered down the borehole this week showed that dissolved minerals were far more abundant in the lake itself

The fact that we see high concentrations is suggestive that there’s some interesting water-rock-microbe interaction that’s going on

Microbes, in other words, might well be munching on minerals under the ice sheet

will take months or years to unravel this picture

will perform experiments to see whether microbes taken from the lake metabolize iron, sulfur, or other components of minerals

will analyze the DNA of those microbes to see whether they’re related to rock-chewing bacteria that are already known to science.

Antarctica isn’t the only place in the solar system where water sits concealed in the dark beneath thick ice. Europa and Enceladus (moons of Jupiter and Saturn, respectively) are also thought to harbor oceans of liquid water. What is learned at Lake Whillans could shed light on how best to look for life in these other places

Each tweak stops a cursor that continuously scans text on a screen facing the scientist.

Intel chief technology officer

noted that Hawking can actually make a number of other facial expressions as well that might also be used to speed up the rate at which the physicist conveys his thoughts

Even providing Hawking with two inputs would give him the ability to communicate using Morse code

Intel has since the late 1990s supplied Hawking with technology to help the scientist express himself

The latest chapter in their work together began in late 2011 when Hawking reached out to

inform

the Intel co-founder and father of Moore’s law that the physicist’s ability to compose text was slowing and inquiring whether Intel could help.

met with Hawking early last year around the time of the latter’s 70th birthday celebration in Cambridge, where the Intel CTO was one of the speakers

After meeting with Hawking

he wondered whether his company’s processor technology could restore the scientist’s ability to communicate at five words per minute, or even increase that rate to 10

Intel is now working on a system that can use Hawking’s cheek twitch as well as mouth and eyebrow movements to provide signals to his computer

built a new, character-driven interface in modern terms that includes a better word predictor

company is also exploring the use of facial-recognition software to create a new user interface for Hawking that would be quicker than selecting individual letters or words

A black box beneath his wheelchair contains an audio amplifier, voltage regulators and a USB hardware key that receives the input from an infrared sensor on Hawking’s eyeglasses, which detects changes in light as he twitches his cheek

current setup includes a tablet PC with a forward-facing Webcam that he can use to place Skype calls

A hardware voice synthesizer sits in another black box on the back of the chair and receives commands from the computer via a USB-based serial port

Intel’s work with Hawking is part of the company’s broader research into smart gadgets as well as assistive technologies for the elderly

The key to advancing smart devices—which have been at a plateau over the past five or six years—is context awareness

Devices will really get to know us the way a friend would, understanding how our facial expressions reflect our mood

Intel’s plan for identifying personal context requires a combination of hardware sensors—camera, accelerometer, microphone, thermometer and others

with software that can check one’s personal calendar, social networks and Internet browsing habits, to name a few.

use this [information] to reason your current context and what's important at any given time [and deliver] pervasive assistance

One approach to “pervasive assistance” is the Magic Carpet, a rug that Intel and GE developed with embedded sensors and accelerometers that can record a person’s normal routine and even their gait, sounding an alert when deviations are detected.

Such assistance will anticipate our needs, letting us know when we are supposed to be at an appointment and even reminding us to carry enough cash when running certain errands

Imagine going to the doctor for your aching knees

what if your doctor could actually listen to your body, monitoring the way your knees sound as they bend and flex

an instrument called a Surface Forces Apparatus (SFA), a device that measures the adhesion and friction forces between surfaces—in this case cartilage, the pad of tissue that covers the ends of bones at a joint.

degeneration of cartilage is the most common cause of osteoarthritis: The pads wear away, leaving bone grinding against bone

researchers found is that it isn't just any kind of friction that leads to the irreversible wear and tear on the material

currently believed that a high-friction force, or 'coefficient of friction,' is the primary factor in surface wear and damage

found is that this is not the case

The critical feature is not a high-friction force, but what is known as "stick-slip" friction, or, sometimes, "stiction."

Both are characterized by surfaces that initially stick together, and then accelerate away quickly once the static friction force is overcome

With stick-slip friction, the surfaces eventually pull slightly apart and slide across each other, stick again, and pull apart, causing jerky movements.

That's when things get damaged microscopically

Stick-slip is a common phenomenon. It is responsible for everything from computer hard drive crashes and automobile failures, to squeaking doors and music

same thing happens with a violin string

Even if you're pulling the bow steadily, it's moving in hundreds or thousands of little jerks per second, which determine the sound you hear

Each little jerk, no matter how submicroscopic, is an impact, and over time the accumulation of these impacts can deform surfaces, causing irreparable damage—first microscopically, then growing to macroscopic

it's not easy to tell the difference between types of friction at the microscopic level

Smooth-sliding joints might feel the same as those undergoing stiction, or the even more harmful stick-slip, especially in the early stages of arthritis

when measured with an ultra-sensitive and high-resolution instrument like the SFA, each type of friction revealed its own characteristic profile

Smooth-sliding joints yielded an almost smooth constant line (friction force or friction trace

with stiction showed up as a peak, as the "sticking" was being overcome, followed by a relatively smooth line

stick-slip shows the jagged saw-tooth profile of two surfaces repeatedly pulling apart, sticking, and pulling apart again

these measurements could be recorded by placing an acoustic or electric sensing device around joints, giving a signal similar to an EKG.

this could be a good way to measure and diagnose damage to the cartilage

to measure the progression, or even the early detection of symptoms related to arthritis

Early detection of conditions like arthritis has been a priority for many years

the functioning of joints is more complicated

scientists will continue their work by studying synovial fluid—the lubricating fluid between two cartilage surfaces in joints

plays a major role in whether or not the surfaces wear and tear, and the synergistic roles of the different molecules (proteins, lipids, and polymers

all involved in lubricating and preventing damage to our joints.

a number of directions to take, both fundamental and practical

it looks as if we need to focus our research on finding ways to prevent stick-slip motion, rather than lowering the friction force

High achievers also were more likely to form strong connections with other students and to exchange information in more complex ways

tended to form cliques, shutting out low-performing students from their interactions

Students who found themselves shut out were not only more likely to have lower grades; they were also more likely to drop out of the class entirely.

Elite groups of highly connected individuals formed in the first days of the course

"For the first time, we showed that there is a very strong correspondence between social interaction and exchange of information - a 72 percent correlation

almost equally interesting is the fact that these high-performing students form 'rich-clubs', which shield themselves from low-performing students, despite the significant efforts by these lower-ranking students to join them.

weaker students try hard to engage with the elite group intensively, but can't. This ends up having a marked correlation with their dropout rates

might better identify patterns in the classroom that can trigger early dropout alarms

allowing more time for educators to help the student and, ideally, reduce those rates through appropriate social network interventions.

work is part of

wider research effort at the intersection of the computer and social sciences

enhance our understanding of the ways in which people share information and how this impacts areas of national significance, such as the spread of health-related or political behavior.

ctions for what would result from the commanded motions.

next step is an overnight pre-load test, to gain assurance that the large temperature change from day to night at the rover's location does not add excessively to stress on the arm while it is pressing on the drill

air temperature plunges from about 32 degrees Fahrenheit (zero degrees Celsius) in the afternoon to minus 85 degrees Fahrenheit (minus 65 degrees Celsius) overnight

Over this temperature swing, this large rover's arm, chassis and mobility system grow and shrink by about a tenth of an inch (about 2.4 millimeters), a little more than the thickness of a U.S. quarter-dollar coin

Remaining preparatory steps will take at least the rest of this week

Some of these steps are hardware checks. Others will evaluate characteristics of the rock material at the selected drilling site on a patch of flat, veined rock called "John Klein

We are proceeding with caution in the approach to Curiosity's first drilling. This is challenging. It will be the first time any robot has drilled into a rock to collect a sample on Mar

"drill-on-rock checkout" will use the hammering action of Curiosity's drill briefly, without rotation of the drill bit, for assurance that the back-and-forth percussion mechanism and associated control system are properly tuned for hitting a rock

the surface of the rock while penetrating less than eight-tenths of an inch (2 centimeters).

"mini-drill" is designed to produce a small ring of tailings -- powder resulting from drilling

will not go deep enough to push rock powder into the drill's sample-gathering chamber

The rover team's activities this week are affected by the difference between Mars time and Earth time

To compensate for this, the team develops commands based on rover activities from two sols earlier

the mini-drill activity cannot occur sooner than two sols after the drill-on-rock checkout.

Martian sol lasts about 40 minutes longer than a 24-hour Earth day.