Significant impact of the East Asia monsoon on ozone seasonal behavior in the boundary layer of Eastern China and the west Pacific region

The impact of the East Asia monsoon on the seasonal behavior of O<sub>3</sub> in the boundary layer of Eastern China and the west Pacific region was analyzed for 2004–2006 by means of full-year nested chemical transport model simulations and continuous observational data obtained from three inland mountain sites in central and eastern China and three oceanic sites in the west Pacific region. The basic common features of O<sub>3</sub> seasonal behaviors over all the monitoring sites are the pre- and post-monsoon peaks with a summer trough. Such bimodal seasonal patterns of O<sub>3</sub> are predominant over the region with strong summer monsoon penetration, and become weaker or even disappear outside the monsoon region. The seasonal/geographical distribution of the pre-defined monsoon index indicated that the East Asia summer monsoon is responsible for the bimodal seasonal O<sub>3</sub> pattern, and also partly account for the differences in the O<sub>3</sub> seasonal variations between the inland mountain and oceanic sites. Over the inland mountain sites, the O<sub>3</sub> concentration increased gradually from the beginning of the year, reached a maximum in June, decreased rapidly to the summer valley in July or August, and then peaked in September or October, thereafter decreased gradually again. Over the oceanic sites, O<sub>3</sub> abundance showed a similar increasing trend beginning in January, but then decreased gradually from the end of March, followed by a wide trough with the minimum in July and August and a small peak in October or November. A sensitivity analysis performed by setting China-emission to zero revealed that the chemically produced O<sub>3</sub> from China-emission contributed substantially to the O<sub>3</sub> abundance, particularly the pre- and post-monsoon O<sub>3</sub> peaks, over China mainland. We found that China-emission contributed more than 40% to total boundary layer O<sub>3</sub> during summertime (60–70% in July) and accounted for about 40 ppb of each peak value over the inland region if without considering the effect of the nonlinear chemical productions. In contrast, over the oceanic region in the high monsoon index zone, the contribution of China-emission to total boundary layer O<sub>3</sub> was always less than 20% (<10 ppb), and less than 10% in summer

A Population of Faint Non-Transient Low Mass Black Hole Binaries

We study the thermal and viscous stability of accretion flows in Low Mass Black Hole Binaries (LMBHBs). We consider a model in which an inner advection-dominated accretion flow (ADAF) is surrounded by a geometrically thin accretion disk, the transition between the two zones occurring at a radius R_tr. In all the known LMBHBs, R_tr appears to be such that the outer disks could suffer from a global thermal-viscous instability. This instability is likely to cause the transient behavior of these systems. However, in most cases, if R_tr were slightly larger than the estimated values, the systems would be globally stable. This suggests that a population of faint persistent LMBHBs with globally stable outer disks could be present in the Galaxy. Such LMBHBs would be hard to detect because they would lack large amplitude outbursts, and because their ADAF zones would have very low radiative efficiencies, making the systems very dim. We present model spectra of such systems covering the optical and X-ray bands.Comment: LateX, 37 pages, 11 figures; Accepted for publication in The Astrophysical Journa

Physical Acoustics

Contains reports on seven research projects.Office of Naval Research (Contract Nonr-1841(42

Systematic analysis of interannual and seasonal variations of model-simulated tropospheric NO₂ in Asia and comparison with GOME-satellite data

International audienceSystematic analyses of interannual and seasonal variations of tropospheric NO2 vertical column densities (VCDs) based on GOME satellite data and the regional scale chemical transport model (CTM), Community Multi-scale Air Quality (CMAQ), are presented over eastern Asia between 1996 and June 2003. A newly developed year-by-year emission inventory (REAS) was used in CMAQ. The horizontal distribution of annual averaged GOME NO2 VCDs generally agrees well with the CMAQ results. However, CMAQ/REAS results underestimate the GOME retrievals with factors of 2?4 over polluted industrial regions such as Central East China (CEC), a major part of Korea, Hong Kong, and central and western Japan. For the Japan region, GOME and CMAQ NO2 data show good agreement with respect to interannual variation and show no clear increasing trend. For CEC, GOME and CMAQ NO2 data show good agreement and indicate a very rapid increasing trend from 2000. Analyses of the seasonal cycle of NO2 VCDs show that GOME data have systematically larger dips than CMAQ NO2 during February?April and September?November. Sensitivity experiments with fixed emission intensity reveal that the detection of emission trends from satellite in fall or winter have a larger error caused by the variability of meteorology. Examination during summer time and annual averaged NO2 VCDs are robust with respect to variability of meteorology and are therefore more suitable for analyses of emission trends. Analysis of recent trends of annual emissions in China shows that the increasing trends of 1996?1998 and 2000?2002 for GOME and CMAQ/REAS show good agreement, but the rate of increase by GOME is approximately 10?11% yr?1 after 2000; it is slightly steeper than CMAQ/REAS (8?9% yr?1). The greatest difference was apparent between the years 1998 and 2000: CMAQ/REAS only shows a few percentage points of increase, whereas GOME gives a greater than 8% yr?1 increase. The exact reason remains unclear, but the most likely explanation is that the emission trend based on the Chinese emission related statistics underestimates the rapid growth of emissions

Cosmogenic 11C production and sensitivity of organic scintillator detectors to pep and CNO neutrinos

Several possible background sources determine the detectability of pep and CNO solar neutrinos in organic liquid scintillator detectors. Among such sources, the cosmogenic 11C nuclide plays a central role. 11C is produced underground in reactions induced by the residual cosmic muon flux. Experimental data available for the effective cross section for 11C by muons indicate that 11C will be the dominant source of background for the observation of pep and CNO neutrinos. 11C decays are expected to total a rate 2.5 (20) times higher than the combined rate of pep and CNO neutrinos in Borexino (KamLAND) in the energy window preferred for the pep measurement, between 0.8 and 1.3 MeV. This study examines the production mechanism of 11C by muon-induced showers in organic liquid scintillators with a novel approach: for the first time, we perform a detailed ab initio calculation of the production of a cosmogenic nuclide, 11C, taking into consideration all relevant production channels. Results of the calculation are compared with the effective cross sections measured by target experiments in muon beams. This paper also discusses a technique for reduction of background from 11C in organic liquid scintillator detectors, which allows to identify on a one-by-one basis and remove from the data set a large fraction of 11C decays. The background reduction technique hinges on an idea proposed by Martin Deutsch, who suggested that a neutron must be ejected in every interaction producing a 11C nuclide from 12C. 11C events are tagged by a three-fold coincidence with the parent muon track and the subsequent neutron capture on protons.Comment: 11 pages, 6 figures; added one section detailing comparison with previous estimates; added reference

CpG site degeneration triggered by the loss of functional constraint created a highly polymorphic macaque drug-metabolizing gene, CYP1A2

<p>Abstract</p> <p>Background</p> <p>Elucidating the pattern of evolutionary changes in drug-metabolizing genes is an important subject not only for evolutionary but for biomedical research. We investigated the pattern of divergence and polymorphisms of macaque <it>CYP1A1 </it>and <it>CYP1A2 </it>genes, which are major drug-metabolizing genes in humans. In humans, <it>CYP1A2 </it>is specifically expressed in livers while <it>CYP1A1 </it>has a wider gene expression pattern in extrahepatic tissues. In contrast, macaque <it>CYP1A2 </it>is expressed at a much lower level than <it>CYP1A1 </it>in livers. Interestingly, a previous study has shown that <it>Macaca fascicularis CYP1A2 </it>harbored unusually high genetic diversity within species. Genomic regions showing high genetic diversity within species is occasionally interpreted as a result of balancing selection, where natural selection maintains highly diverged alleles with different functions. Nevertheless many other forces could create such signatures.</p> <p>Results</p> <p>We found that the <it>CYP1A1/2 </it>gene copy number and orientation has been highly conserved among mammalian genomes. The signature of gene conversion between <it>CYP1A1 </it>and <it>CYP1A2 </it>was detected, but the last gene conversion event in the simian primate lineage occurred before the <it>Catarrhini-Platyrrhini </it>divergence. The high genetic diversity of macaque <it>CYP1A2 </it>therefore cannot be explained by gene conversion between <it>CYP1A1 </it>and <it>CYP1A2</it>. By surveying <it>CYP1A2 </it>polymorphisms in total 91 <it>M. fascicularis </it>and <it>M. mulatta</it>, we found several null alleles segregating in these species, indicating functional constraint on <it>CYP1A2 </it>in macaques may have weakened after the divergence between humans and macaques. We propose that the high genetic diversity in macaque <it>CYP1A2 </it>is partly due to the degeneration of CpG sites, which had been maintained at a high level by purifying selection, and the rapid degeneration process was initiated by the loss of functional constraint on macaque <it>CYP1A2</it>.</p> <p>Conclusions</p> <p>Our findings show that the highly polymorphic <it>CYP1A2 </it>gene in macaques has not been created by balancing selection but by the burst of CpG site degeneration after loss of functional constraint. Because the functional importance of <it>CYP1A1/2 </it>genes is different between humans and macaques, we have to be cautious in extrapolating a drug-testing data using substrates metabolized by <it>CYP1A </it>genes from macaques to humans, despite of their somewhat overlapping substrate specificity.</p

Physical Acoustics

Contains reports on four research projects.U. S. Navy (Office of Naval Research) under Contract N00014-67-A-0204-0019Joint Services Electronics Programs (U.S. Army, U.S. Navy, and U.S. Air Force) under Contract DA 28-043-AMC-02536(E