Collective modes of a collisional anisotropic quark-gluon plasma

In this paper we consider the collective modes of a momentum-space anisotropic quark-gluon plasma taking into account the effect of collisions between the plasma constituents. Our analysis is carried out using a collisional kernel of Bhatnagar-Gross-Krook form and extends prior analyses in the literature by considering all possible angles of propagation of the gluonic modes relative to the momentum-anisotropy axis. We extract both the stable and unstable modes as a function of the collision rate and confirm prior findings that gluonic unstable modes can be eliminated from the spectrum if the collision rate is sufficiently large. In addition, we discuss the conditions necessary for the existence of unstable modes and present evidence that unstable mode growth rates are maximal for modes with momentum along the anisotropy direction. Finally, we demonstrate that when there is a finite collisional rate, gluonic unstable modes are absent from the spectrum at both small and large momentum anisotropy. These results pave the way for understanding the impact of collisions on a variety of non-equilibrium quark-gluon plasma observables.Comment: 19 pages and 15 figure

The Excitation of Guided-waves by Underground Point Source: an Investigation with Theoretical Seismograms

AbstractNear-Source scattering of Rg into S appears to be the primary contributor to the low-frequency Lg. The authors further suggest that the prominent low-frequency spectral null in Lg is due to Rg from a compensated linear vector dipole (CLVD) source, and the low-frequency null in Rg excitation is due to a zero-crossing of the horizontal displacement eigenfunctions. In this study, the mechanism of the excitation of Lg from explosions in layered earth structures are analyzed with theoretical seismograms. Our result shows that the CLVD source generates prominent Lg waves,and the null in the Lg spectra showing remarkably good agreement with those expected from Rg due to a CLVD source. We conclude that the derivative of displacement eigenfunction also takes a key role in the excitation of the null, only zero-crossing of the horizantall displacement eigenfunction can not fully explain it

Changes of Circulating Transforming Growth Factor-²1 Level During Radiation Therapy Are Correlated with the Prognosis of Locally Advanced Non-small Cell Lung Cancer

IntroductionWe hypothesized that plasma transforming growth factor-²1 (TGF-²1) level and its dynamic change are correlated with the prognosis of locally advanced non-small cell lung cancer (NSCLC) treated with radiation therapy (RT).MethodsPatients with stage IIIA or IIIB NSCLC treated with RT with or without chemotherapy were eligible for this study. Platelet poor plasma was collected from each patient within 1 week before RT (pre-RT) and at the 4th week during RT (during-RT). TGF-²1 level was measured with enzyme-linked immunosorbent assay. The primary end point was overall survival (OS) and the secondary end point was progression-free survival (PFS). Kaplan-Meier and Cox regression were used for risk factor evaluation.ResultsA total of 65 patients were eligible for the study. The median OS and PFS were 17.7 and 13.7 months, respectively. In univariate analysis, performance status, weight loss, radiation dose, and TGF-²1 ratio (during-RT/pre-RT TGF-²1 level) were all significantly correlated with OS. In the multivariate analysis, performance status, radiation dose, and TGF-²1 ratio were still significantly correlated with OS. The median OS was 30.7 months for patients with TGF-²1 ratio ≤1 versus 13.3 months for those with TGF-²1 ratio more than 1 (p = 0.0029); and the median PFS was 16.8 months versus 7.2 months, respectively (p = 0.010).ConclusionsIn locally advanced NSCLC, the decrease of TGF-²1 level during RT is correlated with favorable prognosis

A comparison of the climates of the Medieval Climate Anomaly, Little Ice Age, and Current Warm Period reconstructed using coral records from the northern South China Sea

For the global oceans, the characteristics of high-resolution climate changes during the last millennium remain uncertain because of the limited availability of proxy data. This study reconstructs climate conditions using annually resolved coral records from the South China Sea (SCS) to provide new insights into climate change over the last millennium. The results indicate that the climate of the Medieval Climate Anomaly (MCA, AD 900–1300) was similar to that of the Current Warm Period (CWP, AD 1850-present), which contradicts previous studies. The similar warmth levels for the MCA and CWP have also been recorded in the Makassar Strait of Indonesia, which suggests that the MCA was not warmer than the CWP in the western Pacific and that this may not have been a globally uniform change. Hydrological conditions were drier/saltier during the MCA and similar to those of the CWP. The drier/saltier MCA and CWP in the western Pacific may be associated with the reduced precipitation caused by variations in the Pacific Walker Circulation. As for the Little Ice Age (LIA, AD 1550–1850), the results from this study, together with previous data from the Makassar Strait, indicate a cold and wet period compared with the CWP and the MCA in the western Pacific. The cold LIA period agrees with the timing of the Maunder sunspot minimum and is therefore associated with low solar activity. The fresher/wetter LIA in the western Pacific may have been caused by the synchronized retreat of both the East Asian Summer Monsoon and the Australian Monsoon

Responses of Phaseolus calcaltus to lime and biochar application in an acid soil

Introduction Rice bean (Phaseolus calcaltus), as an annual summer legume, is always subjected to acid soils in tropical to subtropical regions, limiting its growth and nodulation. However, little is known about its responses to lime and biochar addition, the two in improving soil fertility in acid soils. Materials and Methods In the current study, a pot experiment was conducted using rice bean on a sandy yellow soil (Orthic Acrisol) with a pH of 5.5. The experiment included three lime rates (0, 0.75 and 1.5 g kg−1) and three biochar rates (0, 5 and 10 g kg−1). The biochar was produced from aboveground parts of Solanum tuberosum using a home-made device with temperature of pyrolysis about 500 °C. Results and Discussion The results indicated that both lime and biochar could reduce soil exchange Al concentration, increase soil pH and the contents of soil microbial biomass carbon and microbial biomass nitrogen, and enhance urease and dehydrogenase activities, benefiting P. calcaltus growth and nodulation in acid soils. Lime application did decrease the concentrations of soil available phosphorus (AP) and alkali dispelled nitrogen (AN), whereas biochar application increased the concentrations of soil AP, AN and available potassium (AK). However, sole biochar application could not achieve as much yield increase as lime application did. High lime rate (1.5 g lime kg−1) incorporated with low biochar rate (5 g biochar kg−1) could obtain higher shoot biomass, nutrient uptake, and nodule number when compared with high lime rate and high biochar rate. Conclusion Lime incorporated with biochar application could achieve optimum improvement for P. calcaltus growing in acid soils when compared with sole lime or biochar addition

Insight-HXMT observations of Swift J0243.6+6124 during its 2017-2018 outburst

The recently discovered neutron star transient Swift J0243.6+6124 has been monitored by {\it the Hard X-ray Modulation Telescope} ({\it Insight-\rm HXMT). Based on the obtained data, we investigate the broadband spectrum of the source throughout the outburst. We estimate the broadband flux of the source and search for possible cyclotron line in the broadband spectrum. No evidence of line-like features is, however, found up to $\rm 150~keV$. In the absence of any cyclotron line in its energy spectrum, we estimate the magnetic field of the source based on the observed spin evolution of the neutron star by applying two accretion torque models. In both cases, we get consistent results with $B\rm \sim 10^{13}~G$, $D\rm \sim 6~kpc$ and peak luminosity of $\rm >10^{39}~erg~s^{-1}$ which makes the source the first Galactic ultraluminous X-ray source hosting a neutron star.Comment: publishe

Overview to the Hard X-ray Modulation Telescope (Insight-HXMT) Satellite

As China's first X-ray astronomical satellite, the Hard X-ray Modulation Telescope (HXMT), which was dubbed as Insight-HXMT after the launch on June 15, 2017, is a wide-band (1-250 keV) slat-collimator-based X-ray astronomy satellite with the capability of all-sky monitoring in 0.2-3 MeV. It was designed to perform pointing, scanning and gamma-ray burst (GRB) observations and, based on the Direct Demodulation Method (DDM), the image of the scanned sky region can be reconstructed. Here we give an overview of the mission and its progresses, including payload, core sciences, ground calibration/facility, ground segment, data archive, software, in-orbit performance, calibration, background model, observations and some preliminary results.Comment: 29 pages, 40 figures, 6 tables, to appear in Sci. China-Phys. Mech. Astron. arXiv admin note: text overlap with arXiv:1910.0443

E-cigarettes use among urban male tobacco smokers age 15 years or older in China

Background There is paucity of data regarding e-cigarette use in China. Monitoring e-cigarette use is important given the rapid increase of e-cigarette use in some countries. We investigated the prevalence and determinants of e-cigarette use among Chinese male urban tobacco smokers, as most Chinese urban residents who use e-cigarettes are male smokers (~90%). Methods We analyzed data from China City Adult Tobacco Surveys, which were conducted in 14 major Chinese cities individually in 2013-14 with 15,008 males aged &#8805;15 years. Current e-cigarette users were defined as persons who reported using e-cigarette daily or less than daily at the time of the survey. We calculated the prevalence of e-cigarette use among male current tobacco smokers. Multivariate logistic regression was used to assess determinants of e-cigarette use, including age, education, quit attempts in the past 12 months, cigarettes smoked per day, and monthly expenditure on cigarettes. Results Among urban male current smokers in China, 3.6% were current e-cigarette users. The likelihood of being current e-cigarette users was significantly higher among: smokers aged 15-29 (OR=2.5) or 30-49 (OR=2.1) years than 50+ years; those who attempted to quit than those who made no attempt (OR=4.5); those with ≥college education than those with ≤high school education (OR=2.6); and those who smoked ≥15 cigarettes per day (OR=2.7) than those who smoked 1-14 cigarettes per day (all p< 0.05). Conclusions Among urban male tobacco smokers in China, current e-cigarette use was higher among those who were younger, had more education, attempted to quit smoking in the past year, and smoked more cigarettes per day. Given that e-cigarettes are not currently regulated and often marketed as healthier alternatives to cigarettes in China, continued monitoring of e-cigarette use is important to inform public health policy, planning, and practice