First axion dark matter search with toroidal geometry

We firstly report an axion haloscope search with toroidal geometry. In this pioneering search, we exclude the axion-photon coupling $g_{a\gamma\gamma}$ down to about $5\times10^{-8}$ GeV$^{-1}$ over the axion mass range from 24.7 to 29.1 $\mu$eV at a 95\% confidence level. The prospects for axion dark matter searches with larger scale toroidal geometry are also considered.Comment: 5 pages, 5 figures, 1 table and to appear in PRD-R

Three Dimensional Structure and Energy Balance of a Coronal Mass Ejection

The Ultraviolet Coronagraph Spectrometer (UVCS) observed Doppler shifted material of a partial Halo Coronal Mass Ejection (CME) on December 13 2001. The observed ratio of [O V]/O V] is a reliable density diagnostic important for assessing the state of the plasma. Earlier UVCS observations of CMEs found evidence that the ejected plasma is heated long after the eruption. We have investigated the heating rates, which represent a significant fraction of the CME energy budget. The parameterized heating and radiative and adiabatic cooling have been used to evaluate the temperature evolution of the CME material with a time dependent ionization state model. The functional form of a flux rope model for interplanetary magnetic clouds was also used to parameterize the heating. We find that continuous heating is required to match the UVCS observations. To match the O VI-bright knots, a higher heating rate is required such that the heating energy is greater than the kinetic energy. The temperatures for the knots bright in Ly$\alpha$ and C III emission indicate that smaller heating rates are required for those regions. In the context of the flux rope model, about 75% of the magnetic energy must go into heat in order to match the O VI observations. We derive tighter constraints on the heating than earlier analyses, and we show that thermal conduction with the Spitzer conductivity is not sufficient to account for the heating at large heights.Comment: 40 pages, 16 figures, accepted for publication in ApJ For associated mpeg file, please see https://www.cora.nwra.com/~jylee/mpg/f5.mp

The locally covariant Dirac field

We describe the free Dirac field in a four dimensional spacetime as a locally covariant quantum field theory in the sense of Brunetti, Fredenhagen and Verch, using a representation independent construction. The freedom in the geometric constructions involved can be encoded in terms of the cohomology of the category of spin spacetimes. If we restrict ourselves to the observable algebra the cohomological obstructions vanish and the theory is unique. We establish some basic properties of the theory and discuss the class of Hadamard states, filling some technical gaps in the literature. Finally we show that the relative Cauchy evolution yields commutators with the stress-energy-momentum tensor, as in the scalar field case.Comment: 36 pages; v2 minor changes, typos corrected, updated references and acknowledgement

Equation of state of the hot dense matter in a multi-phase transport model

Within the framework of a multi-phase transport model, we study the equation of state and pressure anisotropy of the hot dense matter produced in central relativistic heavy ion collisions. Both are found to depend on the hadronization scheme and scattering cross sections used in the model. Furthermore, only partial thermalization is achieved in the produced matter as a result of its fast expansion

Antrodia cinnamomea reduces obesity and modulates the gut microbiota in high-fat diet-fed mice.

BackgroundObesity is associated with gut microbiota dysbiosis, disrupted intestinal barrier and chronic inflammation. Given the high and increasing prevalence of obesity worldwide, anti-obesity treatments that are safe, effective and widely available would be beneficial. We examined whether the medicinal mushroom Antrodia cinnamomea may reduce obesity in mice fed with a high-fat diet (HFD).MethodsMale C57BL/6J mice were fed a HFD for 8 weeks to induce obesity and chronic inflammation. The mice were treated with a water extract of A. cinnamomea (WEAC), and body weight, fat accumulation, inflammation markers, insulin sensitivity and the gut microbiota were monitored.ResultsAfter 8 weeks, the mean body weight of HFD-fed mice was 39.8±1.2 g compared with 35.8±1.3 g for the HFD+1% WEAC group, corresponding to a reduction of 4 g or 10% of body weight (P<0.0001). WEAC supplementation reduced fat accumulation and serum triglycerides in a statistically significant manner in HFD-fed mice. WEAC also reversed the effects of HFD on inflammation markers (interleukin-1β, interleukin-6, tumor necrosis factor-α), insulin resistance and adipokine production (leptin and adiponectin). Notably, WEAC increased the expression of intestinal tight junctions (zonula occludens-1 and occludin) and antimicrobial proteins (Reg3g and lysozyme C) in the small intestine, leading to reduced blood endotoxemia. Finally, WEAC modulated the composition of the gut microbiota, reducing the Firmicutes/Bacteroidetes ratio and increasing the level of Akkermansia muciniphila and other bacterial species associated with anti-inflammatory properties.ConclusionsSupplementation with A. cinnamomea produces anti-obesogenic, anti-inflammatory and antidiabetic effects in HFD-fed mice by maintaining intestinal integrity and modulating the gut microbiota

Photochemical production of O3 in biomass burning plumes in the boundary layer over northern Australia

In situ aircraft measurements of ozone (O3) and its precursors were made over northern Australia in August-September 1999 during the Biomass Burning and Lightning Experiment Phase B (BIBLE-B). A clear positive correlation of O3 with carbon monoxide (CO) was found in biomass burning plumes in the boundary layer (<3 km). The ΔO3/ΔCO ratio (linear regression slope of O3-CO correlation) is found to be 0.12 ppbv/ppbv, which is comparable to the ratio of 0.15 ppbv/ppbv observed at 0-4 km over the Amazon and Africa in previous studies. The net flux of O3 exported from northern Australia during BIBLE-B is estimated to be 0.3 Gmol O3/day. In the biomass burning region, large enhancements of O3 were coincident with the locations of biomass burning hot spots, suggesting that major O3 production occurred near fires (horizontal scale <50 km)

Photochemistry of ozone over the western Pacific from winter to spring

Aircraft measurements of ozone (O3) and its precursors, including NO, CO, H2O, and nonmethane hydrocarbons (NMHCs), were made over the western Pacific in the 20° - 45°N latitude range in January and April-May 2002 during the Pacific Exploration of Asian Continental Emission (PEACE)-A and B campaigns. These measurements have provided data sets that, in combination with Transport and Chemical Evolution over the Pacific (TRACE-P) data taken in March 2001, enable studies of O3 photochemistry from winter to late spring. A photochemical box model is used to calculate ozone formation (F(O3)) and destruction (D(O3)) rates constrained by the observed species concentrations. The values of F(O3) and D(O3) are controlled directly by NO, J(O1D) (O3 photolysis frequency), H2O, OH, and HO2. Changes in HO2 concentration cause corresponding changes in both F(O3) and D(O3) leading to their coupling. Concentrations of these species, which are strongly influenced by photochemistry and transport from the Asian continent, underwent large seasonal variations. In the boundary layer (0-3 km), NO was much higher in January than in April-May, because of stronger winds, lower convective activities, and lower oxidation rates by OH in winter. The net O3 formation rate, given by P(O3) = F(O3) - D(O3), was largely positive in the boundary layer at 30°-45°N (1.5-4 ppbv d-1) in January, mainly because of high NO and low H2O values. Net O3 formation continued from January to the end of March, demonstrating that the western Pacific is an important O3 source region during this season. Net O3 formation nearly ceased by late April/May because of the decrease in NO and the increase in H2O. In the latitude range of 20°-30°N, P(O3) in the boundary layer was positive in January and turned negative by March. The earlier transition was mainly due to lower NO and higher H2O concentrations, combined with weaker transport and higher temperatures than those at 30°-45°N. The upper troposphere (6-12 km) has been shown to be a region of net O3 formation throughout most of the year because of high NO and low H2O. The present study illustrates that a decrease in the net O3 formation rate at 20°-45°N latitude from winter to late spring is explained systematically by the increases in J(O1D), H2O, OH, and HO2 (primarily due to increases in temperature and solar radiation) and the decrease in NO (primarily due to decrease in transport from the Asian continent). Differences in the seasonal variation of O3 photochemistry observed over the North American continent are interpreted in terms of the differences in factors controlling O3 formation and destruction. Copyright 2004 by the American Geophysical Union