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<jats:p> The human genome project is at the halfway point. The genomes of 11 microbes, <jats:italic>Escherichia coli</jats:italic> , and yeast are finished, yet the human genome is only 2 percent finished. The scale-up to finish by 2005 presents a significant challenge. </jats:p>

<jats:p>Ancient duplications and rearrangements of protein-coding segments have resulted in complex gene family relationships. Duplications can be tandem or dispersed and can involve entire coding regions or modules that correspond to folded protein domains. As a result, gene products may acquire new specificities, altered recognition properties, or modified functions. Extreme proliferation of some families within an organism, perhaps at the expense of other families, may correspond to functional innovations during evolution. The underlying processes are still at work, and the large fraction of human and other genomes consisting of transposable elements may be a manifestation of the evolutionary benefits of genomic flexibility.</jats:p>

<jats:p>In order to extract the maximum amount of information from the rapidly accumulating genome sequences, all conserved genes need to be classified according to their homologous relationships. Comparison of proteins encoded in seven complete genomes from five major phylogenetic lineages and elucidation of consistent patterns of sequence similarities allowed the delineation of 720 clusters of orthologous groups (COGs). Each COG consists of individual orthologous proteins or orthologous sets of paralogs from at least three lineages. Orthologs typically have the same function, allowing transfer of functional information from one member to an entire COG. This relation automatically yields a number of functional predictions for poorly characterized genomes. The COGs comprise a framework for functional and evolutionary genome analysis.</jats:p>

<jats:p> Using estimated strain rates across the actively deforming region of Asia to infer variations in viscous stress, it is shown that gradients of stress point uphill toward the center of Tibet, where gravitational potential energy per unit surface area reaches a maximum. Thus, the dynamics of the deformation seem to obey the equation of creeping flow, which expresses a balance between gradients in stress and the gravitational body force. This balance, in the region of the Tibetan plateau, yields an estimate of 10 <jats:sup>22</jats:sup> pascal second for the average viscosity of the Tibetan lithosphere, which is only about 10 to 100 times greater than the viscosity of the convecting upper mantle. </jats:p>

<jats:p>A continuous seismic velocity and reflectivity cross-section of the San Andreas fault system in northern California shows offsets in the lower crust and the Mohorovic̆ić Discontinuity near the San Andreas and Maacama strike-slip faults. These faults may cut through the crust to the upper mantle in a zone less than 10 kilometers wide. The northern California continental margin to the eastern edge of the Coast Ranges is underlain by a high-velocity lowermost crustal layer that may have been emplaced within 2 million years following the removal of the Gorda plate slab. The rapid emplacement and structure within this layer are difficult to reconcile with existing tectonic models.</jats:p>

<jats:p>Polyhedral and tubular graphitic nanoparticles made of carbon layers and boron nitride (BN) layers have been synthesized. These particles were observed in the soot collected on the anode deposit formed by arcing a hafnium diboride rod with graphite in a nitrogen atmosphere. Elemental profiles with subnanometer-scale resolution revealed a strong phase separation between BN layers and carbon layers along the radial direction. Most of these tubes have a sandwich structure with carbon layers both in the center and at the periphery, separated by a few BN layers. This structure provides insight into the atomistic mechanism of nanotube growth in the boron-carbon-nitrogen ternary system and may lead to the creation of nanostructured electronic devices relying on the controlled production of heteroatomic nanotubes.</jats:p>

<jats:p>Polymeric membranes that contain a collection of monodisperse gold nanotubules, with inside diameters of molecular dimensions (less than 1 nanometer), were used in a simple membrane-permeation experiment to cleanly separate small molecules on the basis of molecular size. For example, when such a membrane was presented with an aqueous feed solution containing pyridine (molecular weight 79) and quinine (molecular weight 324), only the smaller pyridine molecule was transported through the nanotubules and into a receiver solution on the other side of the membrane.</jats:p>

<jats:p> A femtosecond mid-infrared pump-probe study of the vibrational and orientational dynamics of the OH-stretching mode of HDO dissolved in D <jats:sub>2</jats:sub> O is presented. The orientational relaxation of the HDO molecules was observed to occur on either a very slow or a very fast time scale, with associated time constants of Ï„ <jats:sub> <jats:italic>R</jats:italic> </jats:sub> = 13 picoseconds and Ï„ <jats:sub> <jats:italic>R</jats:italic> </jats:sub> = 0.7 picosecond. It was observed that strongly hydrogen-bonded water molecules only relax through the slow orientational relaxation process, whereas the fast process dominates for weakly hydrogen-bonded molecules. This suggests that, with respect to orientional dynamics, two distinct molecular species exist in liquid water. </jats:p>

<jats:p> Coherent extreme-ultraviolet radiation extending to wavelengths below the carbon K edge at 4.37 nanometers (nm) has been generated at a repetition rate of 1 kilohertz by focusing 5-femtosecond near-infrared (780 nm) laser pulses into a helium gas jet. The incident light field performs just a few oscillations, which results in the emission of an x-ray supercontinuum rather than discrete harmonics. Owing to the extremely short rise time of the driving pulses, neutral atoms can be exposed to high fields before they are depleted by ionization. As a result, the observed x-ray radiation extends well into the water window and is delivered in a well-collimated beam (divergence less than 1 milliradian). The high repetition rate and spatial coherence result in a brightness of about 5 × 10 <jats:sup>8</jats:sup> photons per square millimeter per square milliradian per second in a 1-percent bandwidth at 4.37 nm, the carbon edge of the water window. The compact laboratory system holds promise as a source for biological holography and nonlinear optics in the x-ray regime. </jats:p>