Uncertainties in the calibrations of star formation rate

The calibrations of star formation rate (SFR) are prone to be affected by many factors, such as metallicity, initial mass function (IMF), evolutionary population synthesis (EPS) models and so on. In this paper we will discuss the effects of binary interactions, metallicity, EPS models and IMF on several widely used SFR calibrations based on the EPS models of Yunnan with and without binary interactions, BC03, SB99, PEGASE and POPSTAR. The inclusion of binary interactions makes these SFR conversion coefficients smaller (less than 0.2dex), and these differences increase with metallicity. The differences in the calibration coefficient between SFR and the luminosity of $\rm H\alpha$ recombination line (C$_{\rm H\alpha}$) and that between SFR and the ultraviolet (UV) fluxes at 1500 and 2800\,$\rm \AA$ (C$_{i, {\rm UV}}$), caused by IMF, are independent of metallicity (0.03-0.33\,dex) except $\Delta$C$_{\rm H\alpha, IMF}$ when using the POPSTAR and $\Delta$C$_{i, {\rm UV, IMF}}$ when using the PEGASE models. Moreover, we find that $L_{\rm 2800}$ is not suitable to the linear calibration of SFR at low metallicities. At last, we compare the effects of these several factors on the SFR calibrations considered in this paper. The effects of metallicity/IMF and EPS models on the C$_{\rm H\alpha}$ and C$_{\rm FIR}$ (the conversion coefficient between SFR and the far-infrared flux) are the largest among these factors, respectively. For the calibration between SFR and C$_{i, {\rm UV}}$, the effects of these several factors are comparable.Comment: 17 pages, 7 figures, 9 tables, accepted by MNRA

Influence of casting temperature on microstructures and mechanical properties of Cu50Zr45.5Ti2.5Y2 metallic glass prepared using copper mold casting [+ Erratum]

We investigated the influence of casting temperatures on microstructures and mechanical properties of rapidly solidified Cu50Zr45.5Ti2.5Y2 alloy. With casting temperatures increasing, the content of the crystalline phase decreases. At high casting temperature, i.e., 1723 K, glass forming ability (GFA) of the present alloy enhanced. It is implied that adjusting casting temperatures could be used for designing the microstructures of bulk metallic glass matrix composite (BMGC). Nano-indentation tests indicated that CuZr phases is a little softer and can accommodate more plastic deformation than the amorphous matrix. Compression tests confirmed that this kind of the second phase (CuZr) precipitated under lower casting temperatures helps to initiate multiple shear bands, resulting in great improvement of mechanical properties of the samples. Our work indicate that casting temperatures lead a great influence on GFA, microstructures and mechanical properties of rapidly solidified alloy and controlling casting temperatures is crucial to the application of BMGs

A trajectory-driven opportunistic routing protocol for VCPS

By exploring sensing, computing and communication capabilities on vehicles, Vehicular Cyber-Physical Systems (VCPS) are promising solutions to provide road safety and traffic efficiency in Intelligent Transportation Systems (ITS). Due to high mobility and sparse network density, VCPS could be severely affected by intermittent connectivity. In this paper, we propose a Trajectory-Driven Opportunistic Routing (TDOR) protocol, which is primarily applied for sparse networks, e.g., Delay/Disruption Tolerant Networks (DTNs). With geographic routing protocol designed in DTNs, existing works primarily consider the proximity to destination as a criterion for nexthop selections. Differently, by utilizing GPS information of onboard vehicle navigation system to help with data transmission, TDOR selects the relay node based on the proximity to trajectory. This aims to provide reliable and efficient message delivery, i.e., high delivery ratio and low transmission overhead. TDOR is more immune to disruptions, due to unfavorable mobility of intermediate nodes. Performance evaluation results show TDOR outperforms well known opportunistic geographic routing protocols, and achieves much lower routing overhead for comparable delivery ratio

Physics perspectives of heavy-ion collisions at very high energy

Heavy-ion collisions at very high colliding energies are expected to produce a quark-gluon plasma (QGP) at the highest temperature obtainable in a laboratory setting. Experimental studies of these reactions can provide an unprecedented range of information on properties of the QGP at high temperatures. We report theoretical investigations of the physics perspectives of heavy-ion collisions at a future high-energy collider. These include initial parton production, collective expansion of the dense medium, jet quenching, heavy-quark transport, dissociation and regeneration of quarkonia, photon and dilepton production. We illustrate the potential of future experimental studies of the initial particle production and formation of QGP at the highest temperature to provide constraints on properties of strongly interaction matter.Comment: 35 pages in Latex, 29 figure

Disparities and risks of sexually transmissible infections among men who have sex with men in China: a meta-analysis and data synthesis.

BACKGROUND: Sexually transmitted infections (STIs), including Hepatitis B and C virus, are emerging public health risks in China, especially among men who have sex with men (MSM). This study aims to assess the magnitude and risks of STIs among Chinese MSM. METHODS: Chinese and English peer-reviewed articles were searched in five electronic databases from January 2000 to February 2013. Pooled prevalence estimates for each STI infection were calculated using meta-analysis. Infection risks of STIs in MSM, HIV-positive MSM and male sex workers (MSW) were obtained. This review followed the PRISMA guidelines and was registered in PROSPERO. RESULTS: Eighty-eight articles (11 in English and 77 in Chinese) investigating 35,203 MSM in 28 provinces were included in this review. The prevalence levels of STIs among MSM were 6.3% (95% CI: 3.5-11.0%) for chlamydia, 1.5% (0.7-2.9%) for genital wart, 1.9% (1.3-2.7%) for gonorrhoea, 8.9% (7.8-10.2%) for hepatitis B (HBV), 1.2% (1.0-1.6%) for hepatitis C (HCV), 66.3% (57.4-74.1%) for human papillomavirus (HPV), 10.6% (6.2-17.6%) for herpes simplex virus (HSV-2) and 4.3% (3.2-5.8%) for Ureaplasma urealyticum. HIV-positive MSM have consistently higher odds of all these infections than the broader MSM population. As a subgroup of MSM, MSW were 2.5 (1.4-4.7), 5.7 (2.7-12.3), and 2.2 (1.4-3.7) times more likely to be infected with chlamydia, gonorrhoea and HCV than the broader MSM population, respectively. CONCLUSION: Prevalence levels of STIs among MSW were significantly higher than the broader MSM population. Co-infection of HIV and STIs were prevalent among Chinese MSM. Integration of HIV and STIs healthcare and surveillance systems is essential in providing effective HIV/STIs preventive measures and treatments. TRIAL REGISTRATION: PROSPERO NO: CRD42013003721

Effect of Garlic Juice on Quality Changes of Oyster (Crassostrea Belcheri) Meat During Chilled Storage

Surat-thani oyster, a big and thin-shell bivalve mollusks, has been registered as Geographical Indicators, GI, as its good taste and delicacy as well as nutritious. Eaten style is raw then there is high risk to face with some disease as oyster is filter feeder. Physical, chemical, microbiological and sensory qualities after the oyster meat treated with the garlic juice at 0, 2 and 3 ml, respectively were monitored. Though initial pH of the control, untreated with garlic juice, was higher compared with the sample treated with 3 ml garlic juice, pH of it (control) was significantly lower (p5) at the end of the storag