Study on the mechanism of open-flavor strong decays

The open-flavor strong decays are studied based on the interaction of potential quark model. The decay process is related to the s-channel contribution of the same scalar confinment and one-gluon-exchange(OGE) interaction in the quark model. After we adopt the prescription of massive gluons in time-like region from the lattice calculation, the approximation of four-fermion interaction is applied. The numerical calculation is performed to the meson decays in $u$, $d$, $s$ light flavor sector. The analysis of the $D/S$ ratios of $b_1\rightarrow \omega \pi$ and $a_1\rightarrow \rho \pi$ show that the scalar interaction should be dominant in the open-flavor decays

Multiphase transport model for heavy ion collisions at RHIC

Using a multiphase transport model (AMPT) with both partonic and hadronic interactions, we study the multiplicity and transverse momentum distributions of charged particles such as pions, kaons and protons in central Au+Au collisions at RHIC energies. Effects due to nuclear shadowing and jet quenching on these observables are also studied. We further show preliminary results on the production of multistrange baryons from the strangeness-exchange reactions during the hadronic stage of heavy ion collisions.Comment: 4 pages, 4 figures, espcrc1.sty included, presented at 15th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions (QM2001), Long Island, New York, January 200

Global patterns, trends, and drivers of water use efficiency from 2000 to 2013

Water use efficiency (WUE; gross primary production [GPP]/evapotranspiration [ET]) estimates the tradeoff between carbon gain and water loss during photosynthesis and is an important link of the carbon and water cycles. Understanding the spatiotemporal patterns and drivers of WUE is helpful for projecting the responses of ecosystems to climate change. Here we examine the spatiotemporal patterns, trends, and drivers of WUE at the global scale from 2000 to 2013 using the gridded GPP and ET data derived from the Moderate Resolution Imaging Spectroradiometer (MODIS). Our results show that the global WUE has an average value of 1.70 g C/kg H2O with large spatial variability during the 14-year period. WUE exhibits large variability with latitude. WUE also varies much with elevation: it first remains relatively constant as the elevation varies from 0 to 1000 m and then decreases dramatically. WUE generally increases as precipitation and specific humidity increase; whereas it decreases after reaching maxima as temperature and solar radiation increases. In most land areas, the temporal trend of WUE is positively correlated with precipitation and specific humidity over the 14-year period; while it has a negative relationship with temperature and solar radiation related to global warming and dimming. On average, WUE shows an increasing trend of 0.0025 g C·kg−1 H2O·yr−1 globally. Our global-scale assessment of WUE has implications for improving our understanding of the linkages between the water and carbon cycles and for better projecting the responses of ecosystems to climate change

Salivary cortisol levels and temporomandibular disorders – A systematic review and meta-analysis of 13 case-control studies

Purpose: To compare salivary cortisol levels between patients with temporomandibular disorders (TMD) and healthy controls.Methods: Pubmed, EMBASE, Web of Science and PsycINFO databases were employed to screen for the included studies. RevMan 5.3 software and RStudio software were used for meta-analysis, while a random-effect model was selected to synthesize the effect with the mean difference (MD).Results: Thirteen studies were eligible and a total of 504 TMD patients and 410 controls were included. The pooled MD of salivary cortisol levels in TMD patients compared to controls was 0.05 (95 %CI = 0.01 - 0.09, p = 0.02), indicating a significantly higher level of salivary cortisol in TMD patients than in the controls. Subgroup analysis suggested studies published later than 2014 showed significant increase of salivary cortisol level in TMD patients when compared to controls (MD = 0.07, 95 % CI = 0.01-0.13, p = 0.03). Besides, high-quality studies presented significant differences with regard to the cortisol level in saliva among individuals with or without TMD (MD = 0.04, 95 %CI = 0.03-0.05, p < 0.01). However, the instability of the results showed by the sensitivity analysis was a hindrance to reaching a definitive conclusion.Conclusion: The findings of this study indicate that salivary cortisol level in TMD patients is significantly higher than in controls. Consequently, supportive psychological treatment is recommended to prevent TMD patients from mood disorders. More high-quality studies are, however, needed to confirm the relationship, considering the high degree of heterogeneity among the studies