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<jats:p> The Intergovernmental Panel on Climate Change (IPCC) has published emission trajectories for CO <jats:sub>2</jats:sub> leading to atmospheric equilibrium in the range of 350 to 1000 parts per million by volume (ppmv). This range does not, however, imply that any one concentration is the appropriate value toward which policies influencing worldwide anthropogenic emissions should aim. Scientists must join the debate, despite the difficulty of pinpointing the correct number; otherwise, action may not be taken. Analysis suggests that a value nearer to 350 ppmv should be adopted, until it can be proven that a higher value is safe. </jats:p>

<jats:p> An ice core record from the Guliya ice cap on the Qinghai-Tibetan Plateau provides evidence of regional climatic conditions over the last glacial cycle. <jats:sup>36</jats:sup> Cl data suggest that the deepest 20 meters of the core may be more than 500,000 years old. The δ <jats:sup>18</jats:sup> O change across Termination I is ∼5.4 per mil, similar to that in the Huascarán (Peru) and polar ice cores. Three Guliya interstadials (Stages 3, 5a, and 5c) are marked by increases in δ <jats:sup>18</jats:sup> O values similar to that of the Holocene and Eemian (∼124,000 years ago). The similarity of this pattern to that of CH <jats:sub>4</jats:sub> records from polar ice cores indicates that global CH <jats:sub>4</jats:sub> levels and the tropical hydrological cycle are linked. The Late Glacial Stage record contains numerous 200-year oscillations in δ <jats:sup>18</jats:sup> O values and in dust, NH <jats:sub>4</jats:sub> <jats:sup>+</jats:sup> , and NO <jats:sub>3</jats:sub> <jats:sup>−</jats:sup> levels. </jats:p>

<jats:p>Highly emissive (with an external quantum yield exceeding 35 percent at a 365-nanometer excitation wavelength) broadband phosphors can be synthesized from a tetraalkoxysilane sol-gel precursor and a variety of organic carboxylic acids. The air-stable phosphors were synthesized at low temperatures (less than 300°C) and displayed broad visible photoluminescence spectra that appeared white to the eye. Water-soluble phosphors can be prepared by the substitution of 3-aminopropyltriethoxysilane for tetraalkoxysilane in the synthesis. These materials are the most efficient extrinsic phosphors that do not contain activator metal ions.</jats:p>

<jats:p> Fossil shells and paleosol carbonate from ancestral Himalayan river deposits provide a <jats:sup>87</jats:sup> Sr/ <jats:sup>86</jats:sup> Sr record of lowland Himalayan river water during the late Neogene. Reconstructed <jats:sup>87</jats:sup> Sr/ <jats:sup>86</jats:sup> Sr river values increased sharply in the late Miocene, probably marking the beginning of exhumation of high- <jats:sup>87</jats:sup> Sr/ <jats:sup>86</jats:sup> Sr metalimestones, more in the central than in the western Himalayas. These results imply that the marine <jats:sup>87</jats:sup> Sr/ <jats:sup>86</jats:sup> Sr record may not be a proxy for silicate weathering or consumption of atmospheric CO <jats:sub>2</jats:sub> resulting from that weathering. </jats:p>

<jats:p>Measurements of the rate of dissipation of kinetic energy around a shallow seamount in the eastern North Pacific show that mixing there is 100 to 10,000 times as large as that far away from the seamount. If such values are typical of other seamounts, mixing across density surfaces in the ocean occurs mainly at their boundaries, and topographically induced mixing may help to explain the discrepancy between the observed intensity of mixing in the interior of the oceans and that required to satisfy models of ocean circulation.</jats:p>

<jats:p>Paleoclimatic records from equatorial East Africa, Antarctica, and Greenland reveal that atmospheric circulation changed abruptly at the early to mid-Holocene transition to full postglacial conditions. A climatic reorganization occurred at all three sites between 8200 and 7800 years ago that lasted 200 years or less and appears to have been related to abrupt transitions in both marine and terrestrial records around the world.</jats:p>

<jats:p>The recent discoveries of extrasolar giant planets, coupled with refined models of the compositions of Jupiter and Saturn, prompt a reexamination of theories of giant planet formation. An alternative to the favored core accretion hypothesis is examined here; gravitational instability in the outer solar nebula leading to giant planet formation. Three-dimensional hydrodynamic calculations of protoplanetary disks show that giant gaseous protoplanets can form with locally isothermal or adiabatic disk thermodynamics. Gravitational instability appears to be capable of forming giant planets with modest cores of ice and rock faster than the core accretion mechanism can.</jats:p>