Technology Trends

Gecko lizards, which can climb any vertical surface and hang from a ceiling with one toe, have fascinated scientists for a long time. Their foot-hairs have a structure which allow them to strongly adhere to any type and shape of surface. Now, according to this short news release from the National Science Foundation (NSF), researchers from the University of Akron, Ohio, have developed synthetic hairs from multiwalled carbon nanotubes (MWNT) that have adhesion forces 200 times higher than those observed with gecko foot-hairs. This could lead to new dry adhesives used in microelectronics, robotics or space applications. Read more…

Here is the first paragraph of the NSF press release (here is another link if you want to see a picture of a gecko lizard).

Renowned for their ability to walk up walls like miniature Spider-Men–or even to hang from the ceiling by one toe–the colorful lizards of the gecko family owe their wall-crawling prowess to their remarkable footpads. Each five-toed foot is covered with microscopic elastic hairs called setae, which are themselves split at the ends to form a forest of nanoscale fibers known as spatulas. So when a gecko steps on almost anything, these nano-hairs make such extremely close contact with the surface that they form intermolecular bonds, thus holding the foot in place.

So researchers from the University of Akron, helped by a $400,000 grant from the NSF, have developed synthetic hairs from carbon nanotubes that have adhesion forces 200 times higher than those observed with gecko foot-hairs. Here is a link to their own news release.

They built new structures, based on multiwalled carbon nanotubes (MWNT) constructed on polymer surfaces with strong nanometer level adhesion. These structures can be used as dry adhesives similar to or stronger than gecko foot-hairs.

Here is an example of such nanostructures.

The pictures above illustrate the topography and force measurement of multiwalled carbon nanotube brushes on PMMA with a scanning force microscope (SPM). (A) and (B) show real SPM height images taken by tapping mode for vertically and horizontally aligned MWNT, respectively. The bars represent 5 nm and 150 nm, respectively (Credit: University of Akron).

[Note:PMMA, which stands for Poly(methyl methacrylate), is a transparent plastic sold under different names, such as Plexiglas, and is often simply called Acrylic.]

The research paper about this work has been published by Chemical Communications on July 5, 2005 under the title “Synthetic gecko foot-hairs from multiwalled carbon nanotubes” (Issue 30, 2005, Pages 3799 - 3801). Here is a link to the short abstract.

We report a fabrication process for constructing polymer surfaces with multiwalled carbon nanotube hairs, with strong nanometer-level adhesion forces that are 200 times higher than those observed for gecko foot-hairs.

The full paper is available for free for registered users of the Institute of Physics for a duration of one month. Here is a link to this paper (PDF format, 3 pages, 313 KB).

For more information, you also can read a previous entry about a related project, “Spider Legs Lead to Better Post-it Notes.”

These two projects don’t follow the same approach, but they have a similar goal: design improved adhesives that will have critical applications in microelectronics, information technology, robotics, space and other areas.

Sources: National Science Foundation news release, via EurekAlert!, August 15, 2005; and various web sites

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• Chemistry
  


• Materials
  


• Nanotechnology
  


• Nature
  


• Science
  

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How is it possible that we perceive our world in 3D when our eyes only register 2D images? And how do we decide in a millisecond if something in front of us is a bouquet of flowers or a painting? Researchers from Johns Hopkins University think they know how our brain is analyzing pictures. They say that their research “answers the century-old question of the basis of subconscious processes in visual perception.” According to the researchers, we’re capable to “process visual information automatically and independently of what we know, think or expect.” This research might lead to future treatments of human brain disorders. Read more…

Here is the introduction of the Johns Hopkins University news release.

The figure is famous: a deceptively simple line drawing that at first glance resembles a vase and, at the next, a pair of human faces in profile. When you look at this figure, your brain must rapidly decide what the various lines denote. Are they the outlines of the vase or the borders of two faces? How does your brain decide?

Below is an illustration describing the problem of interpreting 2D images in terms of objects in a 3D world (Credit: Johns Hopkins University).

Images are composed of regions that correspond to objects in space (A). The boundaries of these regions are generally the contours of objects that occlude more distant parts of the scene (occluding contours). To interpret images successfully, the visual system has to detect these contours and link them to the occluding regions. (B) The light textured region is generally perceived as a tilted square on a dark background, and the light-dark border as the contour of the square. But the display is ambiguous: the square could be a window. (C) The concept of border ownership. The interpretation of a 2D display depends on how the contrast borders are assigned (top). Consider the border marked by a black dot: if the border is assigned left, the square is an object in front of a dark background; if the border is assigned right, the square becomes a piece of background that is seen through a window. Given flat displays without depth cues, the visual system assumes the object interpretation.

The above image and legend come from a paper recently published by Neuron, “Figure and Ground in the Visual Cortex: V2 Combines Stereoscopic Cues with Gestalt Rules.” Here is a link to the full paper (PDF format, 12 pages, 323 KB).

Now, let’s return to the original news release for more explanations.

“Our paper answers the century-old question of the basis of subconscious processes in visual perception, specifically, the phenomenon of figure-ground organization,” said Rudiger von der Heydt, a professor in the Zanvyl Krieger Mind/Brain Institute.

The report, based on recordings of nerve cells in the visual cortex of macaque monkeys, suggests that this automatic processing of images is repeated each time an individual looks at something new, usually three to four times per second. What’s more, the brain provides what von der Heydt calls “a sophisticated program” to select and process the information that is relevant at any given moment.

But the researchers recognize that there are still lots of work to do before treating human brain disorders. Their current research needs to be “complemented by new brain imaging techniques, traditional psychophysics, psychology and computational and theoretical neuroscience.”

Sources: Johns Hopkins University news release, August 9, 2005; and various web sites

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No, it’s not a typo. American biologists have discovered that a common corn fungus is able to blast its spores with an acceleration equivalent to 870,000g (1g is the acceleration caused by Earth’s gravity). According to this Duke University news release, “Corn fungus is nature’s master blaster,” this acceleration breaks the previous natural record by two orders of magnitude. And these spores also travel much faster than rifle bullets, but they don’t go very far, stopping after only 5 millimeters. Is this discovery important for us? Probably not, but this is another story for the fungus. Moving away from the parent, the spores can get into air currents and acquire their independence. Read more…

Let’s start with a picture. The illustration below describes the launching devices of three different organisms (Credit: Steven Vogel).

The fungus Pilobolus is shown with the sporangium on top of the subsporangial swelling just before it shoots upward on a jet of cell sap. Sphaerobolus appears just before and just after a global mass of spores gets sent aloft by eversion of the floor of the cup. The seed Ruellia has been caught just before the end of launch, with each seed propelled upward by motion of the ejaculator beneath it.

Now, why are biologists studying such a phenomenon? Here is the explanation from the Duke University news release — obviously not written in plain English.

The purpose of the study that revealed the fungus’s extraordinary launch capabilities was to better understand the biological mechanism behind the fungal supergun.

Basically, the gun is powered by the buildup of pressure inside the spore-containing fungal fruiting body, called the perithecium, due to the ability of sap to create an osmotic pressure. Such pressure is due to water flowing across a membrane into the perithecium as it tries to equalize the concentration of a salt solution inside the chamber. In the case of the fungus, at question was whether the sugar mannitol or potassium ions were responsible for the osmotic pressure that generated the propulsive force.

The researchers — Frances Trail and Iffa Gaffoor of Michigan State University, and Steven Vogel of Duke University have published their findings in the scientific journal Fungal Genetics and Biology (Volume 42, Issue 6, Pages 528-533, June 2005). Here is a link to the abstract of this paper named “Ejection mechanics and trajectory of the ascospores of Gibberella zeae (anamorph Fuarium graminearum).”

One of the researchers, Steven Vogel, has recently written another paper on the subject, which has been accepted by the Journal of Biosciences, a quarterly journal published by the Indian Academy of Sciences, Bangalore. Here is a link to the full paper named “Living in a physical world: III. Getting up to speed” (PDF format, 10 pages, 278 KB). This article contains a table giving the accelerations for a large variety of biological projectiles. The image above comes from this paper.

And here is Vogel’s conclusion about the Gibberella zeae, the nature’s most powerful known cannoneer.

“An obvious question is why the fungus even bothers. Given the short range of its spores, why bother accelerating to eighty miles per hour to go a mere five millimeters?,” said Vogel. “Since there is almost no air movement at the surface where the spore grows, the real object of the launch is to get the spore even a little ways from the parent, so that it can get into air currents, which will really give the spore some range.”

It seems than even for fungus, kids need to run away from their parents…

Sources: Duke University news release, via EurekAlert!, July 25, 2005; and various web sites

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I’m sure you’ve read dozens of stories about how our cell phones could be dangerous to our health, causing brain tumors for example. But so far, there is not a definitive answer. But now, according to IsraCast, a team of Israeli researchers has discovered that the microwave radiation used by our cell phones could destroy our eyes by causing two kinds of damages to our visual system, including an irreversible one. If the researchers are right, and even if you only occasionally use your cell phone, the lenses in your eyes can suffer from microscopic damages that won’t heal themselves over time. Now, let’s wait until another scientific team says it’s not true…

Here is the introduction of the IsraCast article.

In a recent scientific study conducted by a team of researchers from the Technion, a possible link between microwave radiation, similar to the type found in cellular phones, and different kinds of damage to the visual system was found. At least one kind of damage seems to accumulate over time and not heal, challenging the common view and leading the researchers to the assertion that the duration of exposure is not less important than the intensity of the irradiation. The researchers also emphasized that existing exposure guidelines for microwave radiation might have to change.

The article contains several illustrations, but here is the most spectacular (Credit: The Ruth and Bruce Rappaport Faculty of Medicine at the Technion).

[Above are] microscope photographs of lenses incubated in organ culture conditions for 12 days. Right frame shows Control lens with no damage. Bottom frame demonstrates the effect of microwave radiation on bovine lens sutures for a total exposure of 192 cycles (1.1GHz, 2.22mW). Each cycle lasts 50min followed by 10 min pause.

The potential risks from radiation on our visual system have previously been studied, but until recently, the effects of microwave radiation have not been evaluated.

Before going further, I need to introduce two concepts here. Cell phone companies use the Specific Absorption Rate (SAR) to measure microwave radiation — “it is the average power density absorbed in a given volume per average weight density (Watt/Kg).” “A less common measure is called Specific Energy Absorption (SA), and is defined as the energy density absorbed in the tissue divided by its weight density.”

Now we can look at the experiments.

Eye lenses of one-year-old male calves obtained from a slaughterhouse were exposed to microwave radiation - one eye from each pair used for control. Each exposure session lasted about two weeks. Both control and exposed lens were kept in an incubator at a constant temperature. During this period each exposed lens had experienced up to 2mW of 1.1GHz radiation virtually around the clock, and each hour it was exposed for a 50 minute session followed by a 10 minute break.

And the researchers were able to measure two different effects:

• macroscopic damages affecting the optical quality of the lens, which can gradually heal
  
• and microscopic damages, which don’t heal after the experiments stopped, and are even growing when a new exposure starts

Here are some warnings from one of the researchers.

Professor Levi Schächter, [of the Department of Electrical Engineering at the Technion,] who worked on the research, told IsraCast that attention should be paid not only to the Specific Absorption Rate (SAR) but also to the total energy absorbed by the tissue (SA), which is not currently under supervision by the appropriate regulative authorities.

The latest research work on this subject has been published by Bioelectromagnetics under the name “Localized effects of microwave radiation on the intact eye lens in culture conditions” (Volume 26, Issue 5 , Pages 398-405, May 10, 2005). Here is a link to the abstract, which I reproduce below.

A novel experimental system was used to investigate the localized effects of microwave radiation on bovine eye lenses in culture for over 2 weeks. Using this setup, we found clear evidence that this radiation has a significant impact on the eye lens. At the macroscopic level, it is demonstrated that exposure to a few mW at 1 GHz for over 36 h affects the optical function of the lens. Most importantly, self-recovery occurs if the exposure is interrupted.

At the microscopic level, close examination of the lens indicates that the interaction mechanism is completely different from the mechanism-causing cataract via temperature increase. Contrary to the latter’s effect, that is particularly pronounced in the vicinity of the sutures and it is assumed to be a result of local friction between the edges of the fibers consisting the lens. Even if macroscopically the lens has recovered from the irradiation, microscopically the indicators of radiation impact remain.

Finally, as this study has not been done — yet — on humans, I guess the controversy can begin. And whether you think that cell phones can damage our eyes or not, feel free to post your comments below.

Sources: Iddo Genuth, IsraCast, July 25, 2005; and various web sites

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• Medicine
  
  
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Scientists periodically claim that they have found the lost continent (or island) of Atlantis, even if it’s not even sure it has ever existed. In a conference recently held in the Greek island of Milos, several researchers presented the reasons why Atlantis could have been located in Greece, Malta, Morocco, and even in Ireland, Israel or India. But both Nature and the Geology blog from About.com agree that the most serious candidate is the former island in the Spanish Gulf of Cadiz known today as Spartel Bank. This small island, about 15 kilometers across, which was located near the “Pillars of Hercules” mentioned by Plato, could have been swallowed up by an earthquake, followed by a tsunami, about 10,000 years ago. Even if this makes sense from a geological point of view, this doesn’t mean Atlantis is anything more than a — fascinating — legend.

Lets’s start with Nature.

In a recent paper in Geology, Marc-Andre Gutscher of the European Institute for Marine Studies in Plouzané gives details of one candidate for the lost city: the submerged island of Spartel, west of the Straits of Gibraltar.

The top of this isle lies some 60 metres beneath the surface in the Gulf of Cadiz, having plunged beneath the waves at the end of the most recent ice age as melting glaciers caused the sea level to rise.

Geological evidence has shown that a large earthquake and a tsunami hit this island some 12,000 years ago, at roughly the location and time indicated in Plato’s writings.

And here are some other details from the Geology blog of About.com.

[About 10,000 years ago,] sea level was more than 100 meters below its present elevation and Spartel Bank was an island. In fact, Gutscher’s new mapping of the site shows that it would have been a rather small island at that time, smaller than previously thought. But things change when we add the effects of large subduction earthquakes. As we all know from the Sumatra quake of 2004, large areas of land sink by several meters and more during these events. If we restore the effects of great earthquakes, which Gutscher estimates as recurring every 2000 years or so, then the island would have been higher and larger.

Gutscher proposes that an exceptionally large quake could have dropped Spartel/Atlantis by 10 meters at once, while tsunami waves of 10 meters or greater height would have obliterated any human structures and left the island unrecognizable. A few more subduction earthquakes would have sunk the remaining islets beneath the sea, leaving treacherous muddy shallows, well before Plato’s time.

As it was mentioned above, Gutscher’s latest research work has been published by Geology in its August 2005 issue (Vol. 33, No. 8, pp. 685-688). Here is a link to the abstract of this paper named “Destruction of Atlantis by a great earthquake and tsunami? A geological analysis of the Spartel Bank hypothesis.”

This paper was presented during the Atlantis 2005 conference, held on July 11-13, 2005, in Milos Island, Greece.

Many other papers were also presented and here is a link to all the abstracts. Besides the papers claiming that Atlantis was in one part of the world or another, some of these papers must have been fun to listen to. Here are some examples: “Interpreting Myths: Catastrophism and New Catastrophism” (abstract #29) or “The Novelty of the Atlantis Myth in the Light of Freudian Interpretation” (abstract #9).

Here are some short excerpts from this last paper, presented by Yair Schlein, from the Open University, Israel.

The Atlantis myth illustrates the Ideal regime and serves as a starting point to the description of the state “pathology”, that is to say, the degeneration process of the state that differs from the “physiology” of state that depicts the political structure in a given time. In other words, the myth expresses the inherent causes for the deterioration of the polis.

Freud too, in his book “Civilization and its Discontents”, described society as a self-destructive. The analogous perceptions of the life of an individual to the structure of the state, and the similar characteristics Plato and Freud attributed to the state are surprising.

And for more information on this subject, please read the excellent collection of resources from Wikipedia about Atlantis.

Sources: Andreas von Bubnoff, Nature, July 22, 2005; Andrew Alden, Geology, About.com, July 14, 2005; and various web sites

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Scientists at the University of Manchester, in the UK, have discovered a new class of materials which are one atom thick and exhibit properties previously never thought possible. With these new materials, they are promising us a ‘new industrial revolution.’ Not only these new materials are ultra-thin, but they can also be ultra-strong, highly-insulating or highly-conductive. Apparently, this new class of materials has been validated by the scientific community, and even if some applications are probably decades away, you can expect to see ‘ultra-fast transistors, micromechanical devices and nano-sensors based on the discovered one-atom-thick crystals already in a few years time.’ Read more…

Here is the introduction of the news release from the University of Manchester.

Scientists at The University of Manchester have discovered a new class of materials which have previously only existed in science fiction films and books.

A team of British and Russian scientists led by Professor Andre Geim, [director of the Manchester Centre for Mesoscience and Nanotechnology,] have discovered a whole family of previously unknown materials, which are one atom thick and exhibit properties which scientists had never thought possible.

After this press release lingo, let’s move — gradually — to some more technical details.

The materials have been created by extracting individual atomic planes from conventional bulk crystals by using a technique called ‘micromechanical cleavage’. Depending on a parent crystal, their one-atom-thick counterparts can be metals, semiconductors, insulators, magnets, etc. Previously, it was thought that such thin materials could not exist in principle, but the research team have, for the first time, demonstrated that they are not only possible but fairly easy to make.

Below are some pictures of these very small two dimensional crystals (Credit for images and legend: University of Manchester).

[Here you can see] single-layer crystallites of (a) NbSe₂, (b) graphite, (c) Bi₂Sr₂CaCu₂O_x and (d) MoS₂ visualized by AFM (a,b), SEM (c) and in an optical microscope (d). All scale bars are 1µm.

Dr Kostya Novoselov, a key investigator in this research, added: “Probably the most important part is that our discovery is not limited to just one or two new materials. It is a whole class of new materials, thousands of them. And they have a variety of properties, allowing one to choose a material most appropriate for a particular application.

This fascinating research work has been published by the Proceedings of the National Academy of Sciences (PNAS) in its July 18, 2005 issue under the name “Two-dimensional atomic crystals.” Here is a link to the abstract.

We report free-standing atomic crystals that are strictly 2D and can be viewed as individual atomic planes pulled out of bulk crystals or as unrolled single-wall nanotubes. By using micromechanical cleavage, we have prepared and studied a variety of 2D crystals including single layers of boron nitride, graphite, several dichalcogenides, and complex oxides. These atomically thin sheets (essentially gigantic 2D molecules unprotected from the immediate environment) are stable under ambient conditions, exhibit high crystal quality, and are continuous on a macroscopic scale.

And here is a link to the full paper from which the above figure has been extracted. Below is the conclusion of this paper.

We have demonstrated the existence of 2D atomic crystals that can be prepared by cleavage from most strongly-layered materials. It is most unexpected if not counterintuitive that isolated 2D crystals can be stable at room temperature and in air, leaving aside the fact that they maintain macroscopic continuity and such high quality that their carrier mobilities remain almost unaffected. The found class of 2D crystals offers a wide choice of new materials parameters for possible applications and promises a wealth of new phenomena usually abundant in 2D systems. We believe that, once investigated and understood, 2D crystals can also be grown in large sizes required for industrial applications, matching the progress achieved recently for the case of single-wall nanotubes.

Finally, even if these new materials are only one atom thick, they still have three dimensions. The idea of 2D crystals and materials in our 3D world would be too disturbing. What do you think of these discoveries? Can we really talk about ‘flat’ materials? And will this research lead to a new industrial revolution? Please post your comments below.

Sources: University of Manchester news release, July 18, 2005; and various web sites

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• Future
  
  
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Alex is a 28-year-old grey parrot who lives in a lab at Brandeis University in Waltham, Mass., and can count, identify objects, shapes, colors and materials. And now, Alex has grasped the concept of zero, according to World Science. In fact, Alex can describe the absence of a numerical quantity on a tray containing colored cubes. When a color is missing, Alex consistently identified this “zero quantity” by saying “none.” You might think that this is just a parrot trick, but this research about ‘bird intelligence’ might also help autistic and other learning-disabled children “who have trouble learning language and counting skills.” Read more…

One of the really interesting things about Alex is that it had learned in the past that “none” meant a lack of information. And without any training, when Alex was asked to say how many green or red cubes were on a tray in front of him, he spontaneously said “none” when there was no cubes with this color. In fact, he was able to connect two different concepts, a lack of information and the absence of a quantity. Pretty brilliant parrot, isn’t?

Before going further, below is a picture of Alex in front of his counting blocks (Credit: Brandeis University). And here is a link to a larger version (193 KB).

Now, let’s look at how the researchers made the discovery that Alex possessed a “zero-like concept.”

The story began when researchers started testing Alex to see whether he understood small numbers, between one and six. Zero wasn’t expected of him. The researchers would lay out an array of objects of different colors and sizes, and asked questions such as “what color four?” — meaning which color are the objects of which there are four.

Apparently, Alex was pretty good on these tests, until he got bored. So the researchers “found some more interesting toys to give as rewards.” And here came the decisive experiment.

One of these apparent lapses occurred one day when an experimenter asked Alex “what color three?” Laid out before Alex were sets of two, three and six objects, each set differently colored. Alex insisted on responding: “five.” This made no sense given that the answer was supposed to be a color.

After several tries the experimenter gave up and said: “OK, Alex, tell me: what color five?” “None,” the bird replied. This was correct, in that there was no color that graced exactly five of the objects. The researchers went on to incorporate “none” into future trials, and Alex consistently used the word correctly, they said.

A few days after this article was published, Brandeis University decided to issue a press release adding that Alex was the “first bird to comprehend numerical concept akin to zero.”

“It is doubtful that Alex’s achievement, or those of some other animals such as chimps, can be completely trained; rather, it seems likely that these skills are based on simpler cognitive abilities they need for survival, such as recognition of more versus less,” explained comparative psychologist and cognitive scientist Dr. Irene Pepperberg.

Dr. Pepperberg’s research, which uses a training method called the model-rival technique, also holds promise for teaching autistic and other learning-disabled children who have difficulty learning language, numerical concepts and even empathy.

So far, results using this learning technique with small groups of autistic children have been very promising.

The latest research work about Alex and his comprehension of zero has been published by the Journal of Comparative Psychology in its May 2005 issue (Volume 119, Issue 2) under the name “Number Comprehension by a Grey Parrot (Psittacus erithacus), Including a Zero-Like Concept.” You’ll get to the abstract from this page (scroll to number #8).

A Grey parrot (Psittacus erithacus) that was able to quantify 6 item sets (including subsets of heterogeneous groups, e.g., blue blocks within groupings of blue and green blocks and balls) using English labels was tested on comprehension of these labels, which is crucial for numerical competence . He was, without training, asked “What color/object [number]?” for collections of various simultaneously presented quantities (e.g., subsets of 4, 5, and 6 blocks of 3 different colors; subsets of 2, 4, and 6 keys, corks, and sticks). Accuracy was greater than 80% and was unaffected by array quantity, mass, or contour. His results demonstrated numerical comprehension competence comparable to that of chimpanzees and very young children. He also demonstrated knowledge of absence of quantity, using “none” to designate zero.

For more information, you can buy this article for $11.95.

Finally, if you still want to know more about Irene Pepperberg’s work with gray parrots, you can visit the Alex Foundation, where you’ll find that someday, Alex may be able to read. Amazing…

Sources: World Science, July 2, 2005; and various web sites

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Geophysicists from the University of Colorado at Boulder have developed a new imaging technique to visualize the movement of rocks below the earth’s surface. And they applied this technique to the Himalaya to discover how the Indian plate moves as it passes beneath the Himalayan plateau. They used 29 broadband seismometers installed in Nepal and Tibet to record about 1,700 earthquakes between 2001 and 2003. Now, they think their technique can be used to assess earthquake hazards, even it can’t predict them accurately. Read more…

“We imaged the boundary between the Indian and Asian tectonic plates by developing a new technique that highlights strongly deformed rocks beneath Earth’s surface, and applied it to data we collected with a network of temporary seismic sensors deployed in Nepal and Tibet,” said Vera Schulte-Pelkum, a researcher at the Cooperative Institute for Research in Environmental Sciences (CIRES).

The network included 29 broadband seismometers operated by the CU-Boulder and SUNY Binghamton teams. About 1,700 earthquakes from as far away as Europe, Alaska and Japan were recorded during an 18-month period starting in 2001. The study was funded primarily by the National Science Foundation.

Below is a map showing where the broadband seismometers in Nepal and Tibet were located (Credit: CIRES).

[This location map has two parts:] (a) Overview map with topography. The extent of the study area map in (b) is outlined in red. The location of INDEPTH profiles is indicated in blue. (b) Topography map of the study area. Stations deployed for this study are shown in black (three stations with little to no data owing to equipment problems or vandalism are shown in white). Hypocentres relocated with our network are colour coded by depth (scale in km).

The scientists found a shear zone above the base of the Indian crust beneath the Himalaya.

Shear zones are similar to faults, Schulte-Pelkum said. Faults are brittle structures at or near the surface of the earth, while shear zones are found at depths of 10 miles or more where heat causes more ductile, or flowing, rock movement.

In subduction zones such as where India and Asia collide, however, earthquakes along brittle faults can occur at depth because rock temperatures are cooler, the researchers said.

Of course, this will not help to forecast earthquakes — only to understand them better.

With the team’s new method, geophysicists can study the deep crust and determine the direction rocks are being sheared. The shearing is similar to a deck of cards being spread out on a table, said Sheehan, an associate professor of geological sciences at CU-Boulder and a CIRES researcher. “We can see how the deep crust has moved. Seeing where these structures are and how they have moved in the subsurface helps us better understand where local hazards are.

“If we can more accurately calculate the subsurface geometries, we can improve our estimations of how the ground will shake during an earthquake. We can’t predict earthquakes, but we can get a better idea of how an earthquake’s energy will radiate,” explained Sheehan.

The research work has been published by Nature on June 30, 2005 under the name “Imaging the Indian subcontinent beneath the Himalaya.” Here is a link to the first paragraph and this is an excerpt.

Here we report seismic images both of the decollement at the base of the Himalaya and of the Moho (the boundary between crust and mantle) at the base of the Indian crust. A significant finding is that strong seismic anisotropy develops above the decollement in response to shear processes that are taken up as slip in great earthquakes at shallower depths.

If you want to read the full paper (PDF format, 4 pages, 574 KB), you need to be a subscriber to Nature or purchase the article for $30. The above illustration comes from this paper.

Sources: University of Colorado at Boulder news release, June 29, 2005; and various web sites

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We’re using computers for so long now that I guess that many of you think that our brains are working like clusters of computers. Like them, we can do several things ’simultaneously’ with our ‘processors.’ But each of these processors, in our brain or in a cluster of computers, is supposed to act sequentially. Not so fast! According to a new study from Cornell University, this is not true, and our mental processing is continuous. By tracking mouse movements of students working with their computers, the researchers found that our learning process was similar to other biological organisms: we’re not learning through a series of 0’s and 1’s. Instead, our brain is cascading through shades of grey. Read more…

According to this study, learning — at least language comprehension — is a continuous process.

“For decades, the cognitive and neural sciences have treated mental processes as though they involved passing discrete packets of information in a strictly feed-forward fashion from one cognitive module to the next or in a string of individuated binary symbols — like a digital computer,” said Michael Spivey, a psycholinguist and associate professor of psychology at Cornell.

His experiments are somewhat fascinating — even if limited.

In his study, 42 students listened to instructions to click on pictures of different objects on a computer screen. When the students heard a word, such as “candle,” and were presented with two pictures whose names did not sound alike, such as a candle and a jacket, the trajectories of their mouse movements were quite straight and directly to the candle.

The picture below shows Michael Spivey with one of his students looking at two objects on her screen.

[He asked her] to listen for a word and then to click on its picture. By studying the curvature of the trajectory of the mouse, he can analyze language comprehension processes (Credit: Kevin Stearns, Cornell University).

But when the students heard “candle” and were presented with two pictures with similarly sounding names, such as candle and candy, they were slower to click on the correct object, and their mouse trajectories were much more curved. Spivey said that the listeners started processing what they heard even before the entire word was spoken.

Spivey concludes that our brains can handle ambiguities.

“When there was ambiguity, the participants briefly didn’t know which picture was correct and so for several dozen milliseconds, they were in multiple states at once. They didn’t move all the way to one picture and then correct their movement if they realized they were wrong, but instead they traveled through an intermediate gray area,” explained Spivey.

For more information, the research work has been published online by the Proceedings of the National Academy of Sciences under the name “Continuous attraction toward phonological competitors.” Here is a link to the abstract.

Certain models of spoken-language processing, like those for many other perceptual and cognitive processes, posit continuous uptake of sensory input and dynamic competition between simultaneously active representations. Here, we provide compelling evidence for this continuity assumption by using a continuous response, hand movements, to track the temporal dynamics of lexical activations during real-time spoken-word recognition in a visual context. By recording the streaming x, y coordinates of continuous goal-directed hand movement in a spoken-language task, online accrual of acoustic-phonetic input and competition between partially active lexical representations are revealed in the shape of the movement trajectories. This hand-movement paradigm allows one to project the internal processing of spoken-word recognition onto a two-dimensional layout of continuous motor output, providing a concrete visualization of the attractor dynamics involved in language processing.

The access to the full article will cost you $10.

Now, I have a question for you. Even if this new study is right, what will it change for us? Will you wake up differently tomorrow morning? I don’t think so.

Sources: Susan S. Lang, Cornell News Service, June 27, 2005; and various web sites

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Like many of you, I had a good laugh a month ago when I read that some students at the MIT submitted a computer-generated ’scientific’ paper to a computer conference which accepted it, at least in a first step. (See ‘Prank research paper makes the grade‘ for example.) But now, I’m not laughing anymore. Imagine that 100,000 people around the world use this Automatic CS Paper Generator to generate a fake paper and keep it online. In our world of ‘permanent’ information, what will happen in five years when someone uses a search engine looking for keywords contained in the title of these fake papers? One of these papers may appear high in the list of results and this person may use this computer-generated paper as a basis for one of his projects. Scary, isn’t? Read more…

Let’s first go back to the original story in case you missed it.

On April 15, 2005, the MIT News office wrote that some MIT computer science students were so tired to see their papers rejected by scientific conference people that they started to have some doubts about their standards to accept or refuse a paper. (see link above for more details.)

So they decided to have some fun and to write software that generates meaningless research papers and submit them to different organizations.

One of their computer-generated papers, “Rooter: A Methodology for the Typical Unification of Access Points and Redundancy” (PDF format, 4 pages, 92 KB) was initially accepted by World Multi-Conference on Systemics, Cybernetics and Informatics 2005 (WMSCI 2005) as a non-reviewed paper, and later rejected.

Now, let’s have some fun and build a meaningless computer science paper. It’s very easy. On the site mentioned above, you just fill the names of one to five authors and submit your request. That’s all for you to do!

As an example, here are two fake papers that I ‘co-authored’ with some well-known people in the computer industry.

• “Boolean Logic Considered Harmful” by Linus Torvalds, Bill Gates and Roland Piquepaille (PDF format, 6 pages, 95 KB)


• “A Study of XML Using AcridLamb” by Paul Otellini, Roland Piquepaille and Hector Ruiz (PDF format, 3 pages, 46 KB)

It’s pretty easy to imagine a group of people, with fun or evil intentions, to link to such a computer-generated document in order to see it ranked high by search engines. If enough people are putting a link to the first document mentioned above, a Google search for ‘boolean’ and ‘harmful’ will soon return this fake document as its #1 result.

Of course, I don’t see why people would do that. And the probability that a real paper was co-authored by Bill Gates and Linus Torvalds is very low, so I don’t think anyone will think it’s a genuine document.

But lots of ‘phishing’ attacks these days show that people are more gullible than we might think.

So, is the possibility of hundred of thousands of fake computer science papers sitting online represents a danger or not? Time will tell, but please let me know what you think.

Sources: Roland Piquepaille, with various websites

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In this article, The Scientist reveals a curious and probably unique story. Two years ago, a researcher at Brown University submitted a paper to a scientific medicine journal. Then he received a note from the editor saying that his paper would not interest the journal readers. Thinking that his article was unfairly rejected before peer review, he decided to publish a two-page ad with the contents of his paper in the same journal. He even asked readers if they thought the contents interesting and received 33 positive replies. Read more before telling me what you think and if you’ve heard about a similar story…

First, here are the facts, as described by The Scientist.

Two years ago, David Egilman submitted an editorial to the Journal of Occupational and Environmental Medicine (JOEM) that critiqued a 2003 Dow-funded paper in Texas Medicine that said 11 cases of mesothelioma among Dow workers exposed to asbestos did not “suggest an occupational etiology” — even though mesothelioma typically strikes only 1 to 2 people per million, Egilman said.

He received an E-mail with comments from editor Paul Brandt-Rauf, who said the material was “not likely to be a high priority for the majority of JOEM readers.”

Egilman told The Scientist he believed the article was rejected unfairly, and he wanted to “see what would happen” if he submitted the rejected paper as an advertisement. When he did, it was published in its entirety as a two-page ad in JOEM, along with his survey asking if readers believed this material was a “priority” to them. Egilman said he chose to publish the paper as an advertisement in JOEM, rather than get it peer reviewed at another journal, because he became more interested in finding out if the paper was interesting to JOEM readers.

Of course, publishing a scientific article as an ad raises some issues. If it’s an ad, what is it trying to sell? The author or his ideas?

Then, there is the question of the respective roles of editing and advertising. The JOEM’s editor, Brandt-Rauf, said he would have cancel the ad if he had seen it. But on what grounds? Should he be involved in this kind of decision?

Lee Friedman, director of the Social Policy Research Institute in Illinois, cited a 2002 study in the journal Science and Engineering Ethics showing that 42% of the editors of 33 medical journals owned by professional associations said they had recently received pressure from the association’s leadership over content.

Furthermore, editors are not supposed to be able to veto ads, Friedman added. At many major biomedical journals, such as the Journal of the American Medical Association, the New England Journal of Medicine, editors are “blinded” to which ads are going into which issue, to separate editorial from advertising.

I’m often amazed by the creativity of scientists, but do you think this one went too far? Imagine what would happen if anyone could post his “research” in an ad published by New Scientist or Nature… Tell me what you think.

Sources: Alison McCook, The Scientist, April 29, 2005; and various websites

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Two entomologists at Cornell University who were in charge to name several new species of slime-mold beetles have decided to honor U.S. President George Bush, Vice President Dick Cheney and Secretary of Defense Donald Rumsfeld, according to this news release. These beetles are living in different environments, and pretty far from the White House: the Agathidium bushi lives in Southern Ohio, North Carolina and Virginia, while the Agathidium rumsfeldi and the Agathidium cheneyi come from different regions of Mexico. Anyway, executives from the International Commission on Zoological Nomenclature (ICZN) have some concerns, and these names might not be approved by this organization. Read more…

Here is the beginning of the story.

Two former Cornell University entomologists who recently had the job of naming 65 new species of slime-mold beetles named three species that are new to science in the genus Agathidium for members of the U.S. administration. They are A. bushi Miller and Wheeler, A. cheneyi Miller and Wheeler and A. rumsfeldi Miller and Wheeler.

These naming rules are strongly codified and here is a short explanation.

According to rules established by the International Commission on Zoological Nomenclature, the first word of a new species is its genus; the second word must end in “i” if it’s named after a person; and the final part of the name includes the person or persons who first described the species. That’s why all the new slime-mold beetle species’ names end with Miller and Wheeler.

Before going further, let’s look at a good-looking beetle.

Now, why have these entomologists decided to give the names of U.S. political leaders to some insects?

The decision to name three slime-mold beetles after Bush, Cheney and Rumsfeld, however, didn’t have anything to do with physical features, says Quentin Wheeler, a professor of entomology and of plant biology at Cornell for 24 years until last October, but to pay homage to the U.S. leaders. “We admire these leaders as fellow citizens who have the courage of their convictions and are willing to do the very difficult and unpopular work of living up to principles of freedom and democracy rather than accepting the expedient or popular,” says Wheeler.

So far, eyebrows are raised at the ICZN, but according to its executive secretary, Andrew Polaszek, in this news report, there is no formal opposition to the names of these insects.

“Religion and politics should be kept out of naming of animals,” Mr Polaszek said. “It goes really against the spirit of the [nomenclature] code.”

There are no rules in the code that specifically ban biologists from naming species after political figures. However, it does allow for proposed names to be barred if they cause offence.

So will we see one day A. chiraci or A. blairi species? Who knows?

Finally, for more information about beetles, check this Wikipedia page.

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There are many articles in the press today about the cloning of a champion endurance horse named Pieraz. I want to give my “Best Title of the Month” award to News24, in South Africa, for “Castrated horse becomes dad.” This is true, Pieraz, as most endurance horses, those engaged in races of up to 50 kilometers, was castrated. But its clone, created by Italian and French scientists, and called Pieraz-Cryozootech-Stallion, will be different from the original horse. It might not be able to race, but it will be put to stud to breed other horses within two years. Read more…

Before going further, here are two pictures of the champion horse and his young clone (Credit: Cryozootech).

On the left, you can see Pieraz, ridden by Valerie Kanavy, who was the owner and the trainer of the horse. On the right, Eric Palmer, from Cryozootech, is talking with Pieraz’s clone.

You might also want to look at this short video of Pieraz-Cryozootech-Stallion (RealAudio format, 71 seconds).

Now, here are some details from an article by New Scientist, “First clone of champion racehorse revealed.”

Like most endurance racehorses, Pieraz was castrated young and so cannot breed. The idea of cloning him was to “recreate his testicles” for breeding purposes, says Eric Palmer of Cryozootech, a company based in Paris, France, which supported Galli’s latest cloning work.

[Notes: Cesare Galli produced both horses at the University of Bologna in Cremona, Italy; and Cryozootech is based in Sonchamp, near Paris.]

“The plan is to make this horse a stallion,” says Palmer, and the clone will be mature enough to breed within two years. But although the new clone is Pieraz’s genetic twin, he says there is no guarantee that it will perform as well as the champion racehorse. Environmental factors could be crucial.

Cryozootech has ambitious plans, and wants to clone more than thirty other horses specialized in dressage or jumping. But it’s not that simple. The new foal was the only one which came alive, from 34 embryos implanted into 12 foster mothers.

In “Champion endurance horse cloned,” BBC News gives other details, picking some facts from this Cryozootech press release (PDF format, 1 page).

The new clone, called Pieraz-Cryozootech-Stallion, was born on 25 February, weighing 42kg. He will not be used for competition himself, but will instead make his living siring new generations of horses.

Pieraz, the donor of the genetic material used to create the foal, reached the top of his equestrian discipline in 1994 and 1996. He is owned by the Kanavy family of Fort Valley, Virginia, US. In 2002, Valerie Kanavy heard about cloning and immediately liked the idea that her champion could transmit his qualities to future generations despite being castrated.

And it is obvious that these scientists want to preserve the genetic heritage of this champion and of some others. They will probably make some money too.

What do you think about this cloning experiment?

Update on April 16, 2005: If you understand French, France-Info, an all-news radio station, is airing a short audio segment about this clone, with an interview with Eric Palmer, under the name “Pieraz : le deuxième cheval cloné au monde.”

Here are two links to the text version and to the audio one (RealAudio format, 1 minute and 55 seconds).

Sources: Various websites, April 2005

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The Takanishi Laboratory, at Waseda University, Japan, is home for many robotic projects, including a flutist I wrote about a while ago. Today, let’s look at a talking robot, the Waseda Talker No. 4, or WT-4. This anthropomorphic talking robot was built to better understand how the human vocal mechanism creates speech. The WT-4 has 19 degrees of freedom (DOF) for lungs, vocal cords, tongue, lips, teeth, nasal cavity and soft palate. With its vocal cords, it can produce Japanese vowels that are similar to human ones. The next version, the WT-5, will have even more sophisticated vocal cords. Read more…

Here are more details about the WT-4.

We developed a new anthropomorphic talking robot WT-4 (Waseda Talker No.4) that improved on WT-3. WT-4 had a human-like body to make the communication with a human more easily, and consisted of 1-DOF lungs, 4-DOF vocal cords and articulators (the 7-DOF tongue, 5-DOF lips, 1-DOF teeth, nasal cavity and 1-DOF soft palate), and could reproduce human-like articulatory motion; the total DOF was 19. We improved the connection mechanism between the vocal cords and the vocal tract and developed the new vocal cords. As a result, WT-4 could produce Japanese vowels that were more similar to human vowels than the previous robots and could produce stops, fricatives and nasal sounds of 50 Japanese sounds for human-like speech production.

For more information, two papers about the Wased Talker will be presented at the 149th Meeting of the Acoustical Society of America, which will be held on May 16-20, 2005, in Vancouver, Canada.

The first one, “Development of an anthropomorphic talking robot and the mimicking speech control,” will be about the WT-4 and show “that this mimicking speech control is effective in producing fluent continuous speech by the talking robot.” Here is a link to the abstract.

The second one, “Mechanical vocal cord model mimicking human biological structure,” is about the next version of the Talker, the WT-5. And here are a link to the abstract and a selected quote.

Unlike a musical reed which has been used in conventional mechanical speech synthesizer, the vocal cord model is formed to mimic the human’s vocal cord in the shape and the biological structure. It is made of a thermoplastic rubber, Septonh (Kuraray Co. Ltd.) of which the elasticity like a human’s, and has 3-DOF mechanisms which is similar to the human structure. 1-DOF link mechanism could change the pitch by stretching the length of the vocal cords. The 2-DOF arm mechanism is used to mimic the abduction and adduction of a human arytenoid cartilage.

If you happen to be around Vancouver in May, these two presentations will be given on May 19 in the morning.

Sources: Takanishi Laboratory, Waseda University, Japan; and various websites

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Ocean-diving gliders have a large autonomy, mainly because they don’t have propellers. And they are used to gather oceanographic data such as temperature or salinity at a fraction of the cost of research vessels. Several Seagliders built at the University of Washington (UW) just broke endurance records. Two of these Seagliders, which are 1.8 m long and weigh 52 kg, were launched last September between California and Hawaii and reached the island of Kauai after 191 days in a trip of 1,860 miles. Both Seagliders did more than 500 dives down to 1,000 m during their trips. When a Seaglider reaches the surface, where it stays for only five minutes, it determines its position via GPS, uploads its data and downloads its new instructions via satellite. Meanwhile, two other Seagliders are still somewhere in the Labrador Sea for more than 193 days now and have yet to be retrieved. Read more…

Here are the facts about these Seagliders.

Two ocean-diving gliders built at the University of Washington were retrieved late last month near the Hawaiian island of Kauai after setting a world record by traveling a quarter of the way across the Pacific Ocean. Two other UW gliders, awaiting retrieval from the Labrador Sea, have set another world endurance record with a deployment of 193 days as of early April.

The Seagliders used in the Pacific Ocean were deployed in the water mid-way between California and Hawaii last September. They traveled the Pacific for 191 days, covering 1,860 miles. During that time one made 599 dives and the other 559.

And here are more details about how the Seagliders work.

A Seaglider can dive from the surface down 3,300 feet and back up every 3 to 9 hours. It remains at the surface 5 minutes to transmit ocean data that it has collected, relay its position and receive instructions via the Iridium satellite phone network, before diving again. It travels at half a knot, driven not by a spinning propeller but by buoyancy control: a hydraulic system moves oil in and out of an external rubber bladder to force the glider up or down through the ocean. Moving its battery pack causes it to pitch its nose up or down or roll its wings to change compass heading.

And what are they used for?

The temperature, salinity and oxygen data gathered by the Seagliders will help the North Pacific Acoustics Laboratory scientists better understand acoustic propagation — how sound is affected as it moves through the ocean. Acoustics can be used to probe such things as long-term ocean temperature changes and climate variability, and the role of internal waves in ocean mixing, says Bruce Howe, oceanographer with the UW’s Applied Physics Laboratory.

Gliders also could be used to monitor changes in the world’s oceans because of storms, such as hurricanes, and other natural events, such as El Niño. Sonar and other sensing devices mounted on gliders may one day routinely scan harbors and seaports for explosive mines or detect divers in areas where they don’t belong.

For more information, you should visit the Seaglider home page. You’ll find its specifications, an image gallery and animations (in QuickTime format).

Sources: University of Washington news release, April 5, 2005; and various websites

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