Ever since humans have started planting seeds and harvesting crops, they have unconsciously been selecting some traits of the plants over other traits. This selection process involved nothing more than rejecting the crops that were not suitable for consumption, or had low yield, and using those which were good/easy to eat, and easy to harvest. Over thousands of years, this process has helped domesticate a number of plants, which cannot survive in the wild today and are totally dependent on our abilities as harvesters for their survival.

Corn: Past and Present (Courtesy: PhysOrg)One prime example is the corn (or maize) plant. Corn has been one of the primary crops since antiquity. The North American corn is a direct descendant of a grass called Teosinte, which is found in Mexico, Guatemala and Nicaragua. Researchers have now identified corn genes that were preferentially selected by Native Americans during the course of the plant's domestication.
The corn was domesticated about 6,000 years ago. Out of its 59,000 genes, about 1,200 were preferentially selected during this domestication process. The domesticated corn lost the ability to survive in the wild, produced larger and softer yields, and survived much longer:).
The study was published by University of California, Irvine's Brandon Gaut and his colleagues in the journal Science. Gaut and his coworkers used relatively new genomic techniques to determine the DNA sequence of 700 gene bits in the two plants (modern corn, and ancstral Teosinte) and used population genetics, the study of genetic variation, to compare them.
According to the scientists, the will provide important insights to modern corn breeders in their quest to establish hardier, higher-yielding corn plants. The scientific approach will also be useful in the study of other domesticated organisms, plants and animals alike, and will help us understand the natural processes by which plants and animals were once domesticated by our ancestors:).

Atoms are the fundamental building blocks in chemistry. An atom is composed of a positively charged core called the nucleus (consisting of protons and neutrons), surrounded by a cloud of negatively charged particle(s) called the electrons. The electrons are the prime movers in electricity (where the negatively charged particles travel from the negative to the positive electrode, thus transferring energy), and in electronics (where the flow of electrons or other electrically charged particles is controlled in devices such as semiconductors).

Electron Spin (Courtesy: Prentice-Hall)The electric charge is a fundamental property of particles such as protons or electrons, and is the driver of Electromagnetism. All of our electrical and electronic devices operate on the electrical charge. However, a new concept based on the spin of an electron, is all set to revolutionize the industry.
The spin is a fundamental property associated with sub-atomic particles. Essentially, it is a fixed angular momentum (similar to rotation in our everyday world, but there is no equivalent in sub-atomic physics) intrinsic to the particle. An electron can have a spin of ±h/4∏ (where h is the Planck's constant, and ∏ = 3.1415...). Since an electron can have only two (up or down) spin values, the spin can be used as the basis of a binary system, where say, '0' = up spin, and '1' = down spin.
However, unlike the electric charge, it is very hard to control or manipulate the spin of an electron. This has hampered the development of any device based on the spin of the electron, until now. Physicists in Europe, California and at Ohio University now have found a way to manipulate the spin of an electron with a jolt of voltage from a battery, according to research findings published in the recent issue of the journal Physical Review Letters:):).
In this study, scientists applied voltage to the electron in a quantum dot, which is a tiny, nanometer-sized semiconductor. The burst of power changed the direction of the electron's spin - which can move either up or down. The time taken for such manipulation is about 1 to 20 nanoseconds (corresponding to a frequency of 1GHz), but scientists are confident that this time can be decreased further.
When such a fast switching between up and down spin is possible, it should give rise to new devices based on the spins of single electrons. For example, one could have memories where each bit is stored in the spin of a trapped electron, whereas in today's memories, the bit is represented by the collective charge of millions of electrons:D. These spintronic devices would be 1000 fold smaller than their electronic counterparts, consume less energy, and lead to quantum and optical computers.

The capacity of a removable storage disk has increased rapidly the last two decades. The old 5¼ floppy disks store 360 KB (1.2 MB if high density) of data. The later 3½ floppies store about 1.44 MB. The optical media such as CDs have a maximum capacity of 650 MB (74 minutes audio) to 800 MB (90 minutes audio). Most modern DVDs have a capacity of 4.7 GB. In 2003, Philips announced a dual-layer DVD with a capacity of 8.5 GB. And earlier this month, TDK announced a new 100 GB Blu-ray Disk Prototype.

Soon to be obsolete (Courtesy: Bit-Tech)To top it all, now Toshiba has patented (US No. 6879556) a disk that could store 40 to 100 times more information that a conventional DVD, using more nanometre-scale sloped ridges to diffract light:). The technology, dubbed Articulated Optical Digital Versatile Disk (AO-DVD) could theoretically hold 800 GB :D:D.
Conventional DVDs store information in the form of ridges and depressions, each several hundred nanometres wide. These correspond to bits of binary data - '1's or '0's. The data is read from a disk by bouncing laser light off its surface and measuring the angle at which it reflects.
However, in Iomega's AO-DVD, sub-wavelength surface bumps would slope at slightly different angles - this could be used to encode up to 100 times more information!! Iomega claims the technique could improve data transfer rates by a factor of 30 as well.
Several other groups are also working on increasing the size of an optical disk. For example, a similar technology is being developed at Imperial College London, UK, which uses the polarity of reflected light, instead of its diffraction, to detect sub-wavelength slope features.
It remains to be seen which technique would finally offer the superior advantages to come out at the top. And by the way, a 1.5 TeraByte optical disk is in the pipeline, possibly to enter the market by the year 2010 :):).

The Solar System today is a very stable place. Every planet has a well-defined, nearly circular orbit (except Pluto, which possibly is a planetoid anyway), maintaining a respectful distance from the neighboring planets. But according to a new computer simulation, it was not always like this.
The new simulation uses Chaos Theory to solve certain nagging problems about the formation of the Solar System. The research traces three seemingly unrelated phenomena - the giant planets' (Jupiter, Saturn, Uranus and Neptune) orbits, craters on the Moon, and the behaviour of certain asteroids - to the motions of these giants nearly four billion years ago.

Solar System Salad:).. How many can you identify? (Courtesy: NASA)The work answers the following important questions.

• How did the intense bombardment of the Earth and the Moon start (3.9 billion years ago), that filled the Moon with large lava basins, and delayed the beginning of life on Earth?
  
• Why did Jupiter and Saturn leave their circular orbits and take on the more oval paths seen today, and how did their orbits became so tilted compared to other planets?
  
• Why does Jupiter share its orbit with thousands of asteroids that precede and follow it around the sun?
  

According to the researchers, who are publishing their work in three papers in Nature, the four gas giants originally formed in 10 million years within the current orbit of Uranus. Surrounding them in a ring were several thousand rocky objects called planetesimals, left over from the formation of the planets. Due to gravity, after 700 million years, Saturn had migrated outward and Jupiter inward to the extent that they reached a resonance point. This means they began to march in lockstep with each other, with Jupiter completing two orbits around the Sun for every one of Saturn's. The resonance allowed the pair to greatly disturb the orbits of the other planets :).
In the model, Jupiter and Saturn hurl Uranus and Neptune outwards like bowling balls into a sea of planetesimals, which scatter like pins. Asteroids are hurled inwards towards the smaller planets including the Earth, causing the so-called Late-Heavy-Bombardment (LHB) that rains meteorites on Earth and Moon. Samples of lunar rocks collected by astronauts had dated the impacts at about 650 million years after the formation of the Solar System. Some planetesimals bounce off Saturn's gravity, and get trapped in Jupiter's gravity well, and these (so-called) Trojans are still preceding and following Jupiter in its orbit :D.
This research is elegant, in that it ties together three seemingly disparate phenomena. More studies are needed, but it does seem that three problems have been solved in one master stroke :):).

Evolution is the ever-present change in traits of living creatures over generations, as they adapt to changing environments. According to this theory, as species adapt, different populations adapt to different local environments, and this leads to the gradual emergence of different species. This process is known as speciation. Walking back in time, almost all modern species therefore should be able to derive their ancestry from a single primordial ancestor. Traditionally, this job is done by paleontologists, who study history of life on Earth based on fossil record, and by taxonomists, who maintain and upgrade this hierarchy of extant and extinct species. This hierarchy is also known as the Tree Of Life.

Tree Of Life (Courtesy: TreeOfLife)However, a more modern approach is to find the similarities between the genetic codes of several modern species, and then try to estimate their position on the tree. Since the genetic code runs into millions of base-pairs (the basic unit of DNA), this pattern matching is not trivial. Add in the possibility that there might be random mutations, duplicates, or inverted sequences, and the matching problem becomes a nightmare, which requires extensive computing power:(.
To that end, a new supercomputing cluster designed for the phylogenetic research community has been installed at the San Diego Supercomputer Center. The cluster has 128 Opteron processors each with 4 GB memory, and is supported with a grant from the National Science Foundation in support of the CyberInfrastructure for Phylogenetic Research project, a collaboration of biologists, computer scientists, statisticians and mathematicians at 19 institutions whose goal is to understand the evolutionary relationships between all living organisms.
According to the project leader Mark Miller, the goal is to reconstruct the tree of life for 100,000 species or more. In addition to finding the exact nature of the relationships between the species of the world, the project would also develop new algorithms and database approaches, that will have benefits to research related to data mining, protein decoding, and drug manufacturing:).

The Voyager-1 is an unmanned probe launched on September 5, 1977, and is currently the most distant man-made object in the Solar System. It is currently about 90 AU (about 13.5 billion kms) away, and signal from it takes about 13 hours to reach Earth (in comparison, light from the Sun takes about 8 minutes to reach us). Scientists have long speculated about the eventual exit of the Voyager-1 from the Solar System, which would happen when the probe enters into the heliosheath, which is a vast, turbulent expanse where the Sun's influence ends and particles blown off its surface crash into the thin gas that drifts between the stars.

Voyager Graphic (Courtesy: JPL)Now at last, it is happening: scientists at NASA have confirmed that the probe is currently in the heliosheath, and is fast on its way to interstellar space:):).
Scientists do not really know where the actual edge to interstellar space is. According to the current models, the solar wind (matter and radiation constantly blowing away from the Sun) should get weaker and weaker as we move away from the Sun, and at some distance would collide with the sparse gases found between stars. The region where this collision would occur, is known as the termination shock. At the termination shock, the solar wind slows abruptly from a speed that ranges from 1.1-2.4 million km/h and becomes denser and hotter. One of the final tasks of the Voyager probes is to locate the edge of this termination shock (called the heliopause), beyond which is the interstellar space.
The most persuasive evidence that Voyager-1 has crossed the termination shock is its measurement of a sudden increase in the strength of the magnetic field carried by the solar wind, combined with an inferred decrease in its speed. This happens when the solar wind slows down, and thus the density of charged particles from the Sun increase (imagine a slower traffic: the vehicles are bumper to bumper), with a corresponding increase in the magnetic field. This field strength increased by 1.7 times in November 2003, and again by 2.5 times in December 2004 (and is holding steady ever since). This indicates that the solar wind has perhaps reached a minimum speed, and we are soon to reach this elusive boundary of the Sun's dominion:):).

The current definition of 1 second depends upon the accuracy of the Cesium¹³³ atomic clock. An atomic clock uses the atomic resonance frequency (depends on the time it takes for an electron to jump from excited state to ground state in the outer layers of the atom) as its counter. Since this frequency is a function of the fundamental properties of the atom, it is extremely accurate (small fluctuations can and do exist, due to quantum fluctuations). The Cesium clock is accurate upto 1 part in 10¹⁵, and currently defines the second. However, this atomic clock is hard to stabilize, and this has imposed an inherent upper limit to the accuracy.

Vacuum Chamber to cool atoms using a laser (Courtesy: PhysicsWeb)
Now researchers in Japan have demonstrated a way to trap neutral atoms that could herald a new era in timekeeping. The team believes that an optical clock based on Strontium atoms trapped in an optical lattice could lead to clocks that are accurate to one part in 10¹⁸, and thus a 1000 fold better than the Cesium clocks:):).
The Japanese team first trapped a cloud of 10,000 Strontium atoms at a temperature of just 2 microkelvin in a one-dimensional optical lattice (a very narrow wire). A blue laser cools down the atoms to that temperature. When a light is shined upon the atoms, the atoms get trapped in the crests and troughs of the light wave! So by measuring the number of atoms in a fixed length of wire, the scientists can find the frequency of the light used, and thus set a new standard for the measurement of time:):).