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<jats:p> Ocean microstructure data show that turbulent mixing in the deep Brazil Basin of the South Atlantic Ocean is weak at all depths above smooth abyssal plains and the South American Continental Rise. The diapycnal diffusivity there was estimated to be less than or approximately equal to 0.1 × 104 <jats:sup> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="minus" xlink:type="simple" /> </jats:sup> 4 meters squared per second. In contrast, mixing rates are large throughout the water column above the rough Mid-Atlantic Ridge, and the diffusivity deduced for the bottom-most 150 meters exceeds 5 × 104 <jats:sup> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="minus" xlink:type="simple" /> 4 </jats:sup> meters squared per second. Such patterns in vertical mixing imply that abyssal circulations have complex spatial structures that are linked to the underlying bathymetry. </jats:p>

<jats:p>series of sunlight-irradiated, smog-chamber experiments confirmed that the atmospheric organic aerosol formation potential of whole gasoline vapor can be accounted for solely in terms of the aromatic fraction of the fuel. The total amount of secondary organic aerosol produced from the atmospheric oxidation of whole gasoline vapor can be represented as the sum of the contributions of the individual aromatic molecular constituents of the fuel. The urban atmospheric, anthropogenic hydrocarbon profile is approximated well by evaporated whole gasoline, and thus these results suggest that it is possible to model atmospheric secondary organic aerosol formation.</jats:p>

<jats:p> The silica-supported transition metal hydrides (≡Si-O-Si≡)(≡Si-O-) <jats:sub>2</jats:sub> Ta-H and (≡Si-O-) <jats:sub>x</jats:sub> M-H (M, chromium or tungsten) catalyze the metathesis reaction of linear or branched alkanes into the next higher and lower alkanes at moderate temperature (25° to 200°C). With (≡Si-O-Si≡)(≡Si-O-) <jats:sub>2</jats:sub> Ta-H, ethane was transformed at room temperature into an equimolar mixture of propane and methane. Higher and lower homologs were obtained from propane, butane, and pentane as well as from branched alkanes such as isobutane and isopentane. The mechanism of the step leading to carbon-carbon bond cleavage and formation likely involves a four-centered transition state between a tantalum-alkyl intermediate and a carbon-carbon -bond of a second molecule of alkane. </jats:p>

<jats:p>Temperatures in Jupiter's atmosphere derived from Galileo Probe deceleration data increase from 109 kelvin at the 175-millibar level to 900 ± 40 kelvin at 1 nanobar, consistent with Voyager remote sensing data. Wavelike oscillations are present at all levels. Vertical wavelengths are 10 to 25 kilometers in the deep isothermal layer, which extends from 12 to 0.003 millibars. Above the 0.003-millibar level, only 90- to 270- kilometer vertical wavelengths survive, suggesting dissipation of wave energy as the probable source of upper atmosphere heating.</jats:p>

<jats:p>Observations with the High Resolution Imager on the Rüntgensatellit reveal x-ray emissions from Jupiter's equatorial latitudes. The observed emissions probably result from the precipitation of energetic (&gt;300 kiloelectron volts per atomic mass unit) sulfur and oxygen ions out of Jupiter's inner radiation belt. Model calculations of the energy deposition by such heavy ion precipitation and of the resulting atmospheric heating rates indicate that this energy source can contribute to the high exospheric temperatures (&gt;800 kelvin at 0.01 microbar) measured by the Galileo probe's Atmospheric Structure Instrument. Low-latitude energetic particle precipitation must therefore be considered, in addition to other proposed mechanisms such as gravity waves and soft electron precipitation, as an important source of heat for Jupiter's thermosphere.</jats:p>

<jats:p>The Atmosphere Structure Instrument on the Galileo probe detected wavelike temperature fluctuations superimposed on a 700-kelvin temperature increase in Jupiter's thermosphere. These fluctuations are consistent with gravity waves that are viscously damped in the thermosphere. Moreover, heating by these waves can explain the temperature increase measured by the probe. This heating mechanism should be applicable to the thermospheres of the other giant planets and may help solve the long-standing question of the source of their high thermospheric temperatures.</jats:p>

<jats:p>TRAIL (also known as Apo-2L) is a member of the tumor necrosis factor (TNF) ligand family that rapidly induces apoptosis in a variety of transformed cell lines. The human receptor for TRAIL was found to be an undescribed member of the TNF-receptor family (designated death receptor-4, DR4) that contains a cytoplasmic “death domain” capable of engaging the cell suicide apparatus but not the nuclear factor kappa B pathway in the system studied. Unlike Fas, TNFR-1, and DR3, DR4 could not use FADD to transmit the death signal, suggesting the use of distinct proximal signaling machinery. Thus, the DR4-TRAIL axis defines another receptor-ligand pair involved in regulating cell suicide and tissue homeostasis.</jats:p>

<jats:p> The functions of the ecdysone-induced DHR3 and E75B orphan nuclear receptors in the early stages of Drosophila metamorphosis were investigated. DHR3 represses the ecdysone induction of early genes turned on by the pulse of ecdysone that triggers metamorphosis. It also induces βFTZF1, an orphan nuclear receptor that is essential for the appropriate response to the subsequent prepupal pulse of ecdysone. The E75B receptor, which lacks a complete DNA binding domain, inhibits this inductive function by forming a complex with DHR3 on the <jats:italic>β</jats:italic> FTZF1 promoter, thereby providing a timing mechanism for βFTZF1 induction that is dependent on the disappearance of E75B. </jats:p>

<jats:p> The <jats:italic>Saccharomyces cerevisiae BNI1</jats:italic> gene product (Bni1p) is a member of the formin family of proteins, which participate in cell polarization, cytokinesis, and vertebrate limb formation. During mating pheromone response, bni1 mutants showed defects both in polarized morphogenesis and in reorganization of the underlying actin cytoskeleton. In two-hybrid experiments, Bni1p formed complexes with the activated form of the Rho-related guanosine triphosphatase Cdc42p, with actin, and with two actin-associated proteins, profilin and Bud6p (Aip3p). Both Bni1p and Bud6p (like Cdc42p and actin) localized to the tips of mating projections. Bni1p may function as a Cdc42p target that links the pheromone response pathway to the actin cytoskeleton. </jats:p>

<jats:p>Allometric scaling relations, including the 3/4 power law for metabolic rates, are characteristic of all organisms and are here derived from a general model that describes how essential materials are transported through space-filling fractal networks of branching tubes. The model assumes that the energy dissipated is minimized and that the terminal tubes do not vary with body size. It provides a complete analysis of scaling relations for mammalian circulatory systems that are in agreement with data. More generally, the model predicts structural and functional properties of vertebrate cardiovascular and respiratory systems, plant vascular systems, insect tracheal tubes, and other distribution networks.</jats:p>