B→KπB\to K\pi Decays with 1/mb1/m_b Corrections in QCDQCD Factorization

It is commonly believed that a careful investigation of the subleading terms is crucial for a better understanding of the $QCD$ factorization in charmless B decays. In this work the penguin-dominated $B\to K\pi$ decays are discussed systematically, including the subleading corrections in $1/m_b$ due to soft and hard gluons, besides the annihilation contributions. Soft-gluon effects for all the relevant 4-quark effective operators are calculated within the framework of the light-cone QCD sum rules (LCSR). Our observation is that such soft and hard corrections are less important than the annihilation effects, enhancing only the branching ratios by a few percent; the resultant increase in the branching ratios due to the overall ${\cal O}(1/m_b)$ effects is between about $(22-27)$ of the QCD factorization results with the ${\cal O}(\alpha_s)$ corrections, as the weak phase $\gamma (=\textmd{Im}V_{ub}^*)$ ranges from $40^0$ to $80^0$. Impacts of the involved uncertainties are discussed in some details.Comment: 22 pages,6 figure

Isolation, identification and odour-producing abilities of geosmin/2-MIB in actinomycetes from sediments in Lake Lotus, China

This study aimed to determine whether actinomycetes could contribute to the odours occurring in Lake Lotus, China. In total, 55 actinomycete strains were isolated from sediments in Lake Lotus and their odorous metabolites, geosmin and 2-methylisoborneol (2-MIB), were identified using HSPME-GC-MS. Results showed that 24, 23 and 34 strains produced geosmin and/or 2-MIB in Gause, TSB and M liquid media, respectively. Of odour-producing actinomycetes, most could produce geosmin and some produced both metabolites, while few of them produced only 2-MIB. Six isolates with high-level odour were selected for further investigation. Their biomass and odour-producing abilities were monitored in both the slants and liquid media. The results suggest that TSB was the most suitable medium for the growth of mycelium; Gause and M slant supported good production of spores, while M liquid medium was the most favourable for the production of both geosmin and 2-MIB. Those strains that produced geosmin only were less influenced than those that produced both geosmin and 2-MIB under shaking conditions. The results indicate that actinomycetes from sediments should be taken into consideration when off-flavours occur in water columns. According to the 16S rRNA sequences, six actinomycetes were classified in the Streptomyces

Atomic-layered Au clusters on α-MoC as catalysts for the low-temperature water-gas shift reaction

The water-gas shift (WGS) reaction (where carbon monoxide plus water yields dihydrogen and carbon dioxide) is an essential process for hydrogen generation and carbon monoxide removal in various energy-related chemical operations. This equilibrium-limited reaction is favored at a low working temperature. Potential application in fuel cells also requires a WGS catalyst to be highly active, stable, and energy-efficient and to match the working temperature of on-site hydrogen generation and consumption units. We synthesized layered gold (Au) clusters on a molybdenum carbide (α-MoC) substrate to create an interfacial catalyst system for the ultralow-temperature WGS reaction. Water was activated over α-MoC at 303 kelvin, whereas carbon monoxide adsorbed on adjacent Au sites was apt to react with surface hydroxyl groups formed from water splitting, leading to a high WGS activity at low temperatures

Partonic flow and ϕ\phi-meson production in Au+Au collisions at sNN\sqrt{s_{NN}} = 200 GeV

We present first measurements of the $\phi$-meson elliptic flow ($v_{2}(p_{T})$) and high statistics $p_{T}$ distributions for different centralities from $\sqrt{s_{NN}}$ = 200 GeV Au+Au collisions at RHIC. In minimum bias collisions the $v_{2}$ of the $\phi$ meson is consistent with the trend observed for mesons. The ratio of the yields of the $\Omega$ to those of the $\phi$ as a function of transverse momentum is consistent with a model based on the recombination of thermal $s$ quarks up to $p_{T}\sim 4$ GeV/$c$, but disagrees at higher momenta. The nuclear modification factor ($R_{CP}$) of $\phi$ follows the trend observed in the $K^{0}_{S}$ mesons rather than in $\Lambda$ baryons, supporting baryon-meson scaling. Since $\phi$-mesons are made via coalescence of seemingly thermalized $s$ quarks in central Au+Au collisions, the observations imply hot and dense matter with partonic collectivity has been formed at RHIC.Comment: 6 pages, 4 figures, submit to PR

On the Link between the Subseasonal Evolution of the North Atlantic Oscillation and East Asian Climate

We analyse the impact of the North Atlantic Oscillation (NAO) on the climate of East Asia at subseasonal time scales during both winter and summer. These teleconections have mainly been investigated at seasonal and longer time scales, while higher-frequency links are largely unexplored. The NAO is defined using extended empirical orthogonal functions on pentad-mean observations, which allows to elucidate the oscillation’s spatial and temporal evolution and clearly separate the development and decay phases. The downstream dynamical imprint and associated temperature and precipitation anomalies are quantified by means of a linear regression analysis. It is shown that the NAO generates a significant climate response over East Asia during both the dry and wet seasons, whose spatial pattern is highly dependent on the phase of the NAO’s life cycle. Temperature and precipitation anomalies develop concurrently with the NAO mature phase, and reach maximum amplitude 5–10 days later. These are shown to be systematically related to mid and high-latitude teleconnections across the Eurasian continent via eastward-propagating quasi-stationary Rossby waves instigated over the Atlantic and terminating in the northeastern Pacific. These findings underscore the importance of rapidly evolving dynamical processes in governing the NAO’s downstream impacts and teleconnections with East Asia.</p

Estimation of monthly pan evaporation using support vector machine in Three Gorges Reservoir Area, China

Pan evaporation plays a critical role in estimating water budget and modeling crop water requirements. However, it has been measured at a very limited number of meteorological stations. Estimation of pan evaporation from measured meteorological variables offers an important alternative and drawn increasing attention in the recent years. This paper investigated the performance of support vector machine (SVM) in the estimation of monthly pan evaporation using commonly measured meteorological variables in Three Gorges Reservoir Area in China. Evaluation suggested that SVM models showed remarkable performances and significantly outperformed the empirical model. The SVM model with polynomial as kernel function outperformed that with radial basis function. In the case of unavailable measurements of pan evaporation and meteorological variables to construct the SVM model, pan evaporation can be well-estimated by SVM model developed using data at other sites. The results indicated that the SVM method would be a promising alternative over the traditional approaches for estimating pan evaporation from measured meteorological variables

Strangelet search at RHIC

Two position sensitive Shower Maximum Detector (SMDs) for Zero-Degree Calorimeters (ZDCs) were installed by STAR before run 2004 at both upstream and downstream from the interaction point along the beam axis where particles with small rigidity are swept away by strong magnetic field. The ZDC-SMDs provides information about neutral energy deposition as a function of transverse position in ZDCs. We report the preliminary results of strangelet search from a triggered data-set sampling 100 million Au+Au collisions at top RHIC energy.Comment: Strange Quark Matter 2004 conference proceedin

Strangelet Search in AuAu Collisions at 200 GeV

We have searched for strangelets in a triggered sample of 61 million central (top 4%) Au+Au collisions at \sNN = 200 GeV near beam rapidities at the STAR detector. We have sensitivity to metastable strangelets with lifetimes of order $\geq 0.1 ns$, in contrast to limits over ten times longer in AGS studies and longer still at the SPS. Upper limits of a few 10^{-6} to 10^{-7} per central Au+Au collision are set for strangelets with mass ${}^{>}_{\sim}30$ GeV/c^{2}.Comment: As publishe

Longitudinal double-spin asymmetry for inclusive jet production in p+p collisions at sqrt(s)=200 GeV

We report a new STAR measurement of the longitudinal double-spin asymmetry A_LL for inclusive jet production at mid-rapidity in polarized p+p collisions at a center-of-mass energy of sqrt(s) = 200 GeV. The data, which cover jet transverse momenta 5 < p_T < 30 GeV/c, are substantially more precise than previous measurements. They provide significant new constraints on the gluon spin contribution to the nucleon spin through the comparison to predictions derived from one global fit of polarized deep-inelastic scattering measurements.Comment: 7 pages, 4 figures + 1 tabl