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Currently, there are 24 black hole (BH) X-ray binary systems that have been dynamically confirmed in the Galaxy. Most of them are low-mass X-ray binaries (LMXBs) comprised of a stellar-mass BH and a low-mass donor star. Although the formation of these systems has been extensively investigated, some crucial issues remain unresolved. The most noticeable one is that, the low-mass companion has difficulties in ejecting the tightly bound envelope of the massive primary during the spiral-in process. While initially intermediate-mass binaries are more likely to survive the common envelope (CE) evolution, the resultant BH LMXBs mismatch the observations. In this paper, we use both stellar evolution and binary population synthesis to study the evolutionary history of BH LMXBs. We test various assumptions and prescriptions for the supernova mechanisms that produce BHs, the binding energy parameter, the CE efficiency, and the initial mass distributions of the companion stars. We obtain the birthrate and the distributions of the donor mass, effective temperature and orbital period for the BH LMXBs in each case. By comparing the calculated results with the observations, we put useful constraints on the aforementioned parameters. In particular, we show that it is possible to form BH LMXBs with the standard CE scenario if most BHs are born through failed supernovae., Comment: 20 pages, 13 figures, accepted by MNRAS

Due to the lack of long term pulsed emission in quiescence and the strong timing noise, it is impossible to directly measure the braking index $n$ of a magnetar. Based on the estimated ages of their potentially associated supernova remnants (SNRs), we estimate the values of the mean braking indices of eight magnetars with SNRs, and find that they cluster in a range of $1\sim$42. Five magnetars have smaller mean braking indices of $13$ for other three magnetars are attributed to the decay of external braking torque, which might be caused by magnetic field decay. We estimate the possible wind luminosities for the magnetars with $13$ within the updated magneto-thermal evolution models. Although the constrained range of the magnetars' braking indices is tentative, due to the uncertainties in the SNR ages, which come from distance uncertainties and the unknown conditions of the expanding shells, our method provides an effective way to constrain the magnetars' braking indices if the measurements of the SNRs' ages are reliable, which can be improved by future observations., Comment: 11 Pages, 3 figures, 5 tables, accepted by MNRAS

By introducing Dirac's -function in superhigh magnetic fields, we deduce a general formula for the pressure of degenerate and relativistic electrons, P-e, which is suitable for superhigh magnetic fields, discuss the quantization of Landau levels of electrons, and consider the quantum electrodynamic(QED) effects on the equations of states (EOSs) for different matter systems. The main conclusions are as follows: the stronger the magnetic field strength, the higher the electron pressure becomes; compared with a common radio pulsar, a magnetar could be a more compact oblate spheroid-like deformed neutron star due to the anisotropic total pressure; and an increase in the maximum mass of a magnetar is expected because of the positive contribution of the magnetic field energy to the EoS of the star. Since this is an original work in which some uncertainties could exist, modifications and improvements of our theory should be considered in our future studies. ((c) 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

This study demonstrated a simple method for gold (Au) catalyzed atmospheric pressure chemical vapor deposition (CVD) of tower-like germanium (Ge) nanostructures (denoted as Ge nanotowers) on silicon substrate. The Ge nanotowers have quasi- hexagonal cross-section with a diameter gradually decreasing from the bottom to the top end and sawtooth-faceted sidewalls. The Ge nanotowers are formed in a competitive growth process involving an Au-catalyzed axial growth and lateral growth, which can be controlled by the varied reagent vapor pressure in the CVD growth. The relationship between CVD growth kinetics and the complex morphologies was carefully examined for Ge nanostructures ranging from cylindrical and tapered nanowires to moniliform-shaped and sawtooth faceted hexagonal nanotowers in different deposition zones. The resultant complex Ge nanotowers not only enrich the family of Ge-based nanostructures, but also have potentials as building blocks for Ge-based functional nanodevices.

We present a systematic study of the X-ray binaries (XRBs) containing a black hole (BH) and a non-degenerate companion, in which mass transfer takes place via either capturing the companion's wind or Roche lobe overflow (RLO). As shown in our previous work that focusing on the formation and evolution of detached BH binaries, our assumed models relevant to BH's progenitors predicted significantly different binary properties \citep{sl19}. In this paper, we further follow the evolutionary paths of the BH systems that appearing as XRBs. By use of both binary population synthesis and detailed binary evolution calculations, we can obtain the potential population of BH XRBs. Distributions at the current epoch of various binary parameters have been computed. The observed sample of wind-fed XRBs can be well reproduced under assumption of all our models. The wind-fed XRBs are expected to be so rare ($ \lesssim 100 $) that only a couple of such systems have been detected. Comparison of known RLO XRBs with the calculated distributions of various binary parameters indicates that only the models assuming relatively small masses for BH progenitors can roughly match the observations. Accordingly we estimate that there are hundreds of RLO XRBs in the Milky Way, of which the majority are low-mass XRBs. The RLO systems may become ultraluminous X-ray sources (ULXs) if the BH accretes at a very high rate, we expect that about a dozen ULXs with a BH accretor may exist in a Milky Way$-$like galaxy., Comment: 17 pages, 15 figures, 2 tables, accepted by ApJ

Cultivar renewing is important for the increases of wheat yield. Studying changes of different physiological characteristics in the succession process of wheat varieties has great implications for future breeding. The senescence rate of flag leaf is a key factor affecting winter wheat yield. The variation of photosystem II function during senescence of flag leaves of wheat from different ages is still not clear. 31 wheat varieties planted in Henan Province from different ages since 1941 were examined in this experiment. The variation of photosystem II function was analyzed through measu-ring the relative chlorophyll content, and chlorophyll fluorescence induction dynamics during the senescence of flag leaves which were induced by continued dark. The results showed that the chlorophyll content of flag leaves was gradually increased in the succession of winter wheat. The chlorophyll degradation rate in the leaves of modern varieties was lower than the earlier varieties during the senescnece of flag leaves. Meanwhile, J point of the fluorescence induction kinetics curves in flag leaves of modern varieties increased less than I point. The photosystem II maximum photochemical efficiency and the amount of active reaction centers per unit area gradually increased during succession of wheat varieties, but the reduced extent in leaves of modern varieties was lower than that in the earlier ones. There was no significant correlation between the change of chlorophyll content and F小麦品种的更新换代是小麦产量不断提高的重要因素,阐明小麦品种演替过程中不同生理特性的变化对新品种选育具有重要参考价值.旗叶衰老速率快慢是影响小麦产量水平的关键因素,目前对于不同小麦品种衰老过程中旗叶光系统Ⅱ功能的变化规律尚不清楚.本试验选用1941—2014年间河南地区不同时期种植的31个品种,通过黑暗诱导离体叶片衰老,测定旗叶叶绿素荧光诱导动力学参数、叶绿素相对含量的变化,分析了光系统Ⅱ功能的变化规律.结果表明:品种演替过程中旗叶的叶绿素含量逐渐提高,衰老过程中近代品种叶绿素的降解速率低于较早年代品种;旗叶衰老过程中,近代品种荧光诱导动力学曲线的J点上升幅度小于I点;品种更替过程中光系统Ⅱ最大光化学效率和单位面积有活性反应中心数目逐渐增加,但是近代品种降低速率低于较早年代品种.叶绿素含量的变化与未衰老叶片中

Using two peanut varieties Shanhua108 (early-maturing variety) and 780-15 (late maturing variety), a field experiment was conducted to investigate the influences of row-spacing of wheat (25 cm, 30 cm, 40 cm+20 cm) and two peanut cropping patterns (intercropped peanut with wheat, summer-sowing peanut) on yield components, photosynthetic characteristics, antioxidant system, and dry matter accumulation and transportation. The results showed that wide spacing form of wheat and wide-narrow row planting pattern increased the pod yield, kernel yield, leaf area index, total dry matter accumulation and photosynthetic capacity, as well as SOD, POD and CAT activities, but decreased the MDA content. There are no obvious differences of wheat yield between the two row-spacing. Intercropping system increased peanut yield compared with summer-sowing peanut, which were much higher for wide-narrow row planting pattern than row spacing of 25 cm or 30 cm. The wide-narrow row planting pattern increased the pod yield and kernel yield by 6.3%, 13.3% and 7.7%, 16.5% for Shanhua108 and 780-15 than those of row spacing of 30 cm, respectively. Wide-narrow row planting could enlarge photosynthetic area, improve the net photosynthetic rate, and increase total dry matter accumulation. Meanwhile, it could alleviate the contradictionbetween the plant individual and group, delay the senescence, and increase peanut yield.以大花生品种早熟型‘山花108’和晚熟型‘780-15’为试验材料,设置小麦3种行距配置(25 cm、30 cm、大小行40 cm+20 cm)和2种花生种植方式(麦套、夏直播),探讨不同种植模式对夏花生产量构成、光合特性、抗氧化活性和干物质积累与分配的调控作用.结果表明: 适当扩大小麦行距、相同平均行距下选用大小行种植,可提高套种花生荚果产量和籽仁产量,增大叶面积指数和干物质积累量,增强光合能力,同时提高超氧化物歧化酶、过氧化物酶和过氧化氢酶活性,降低丙二醛含量.麦套花生产量高于夏直播花生并且以大小行处理产量最高.与小麦行距30 cm相比,大小行处理山花108和780-15两品种花生荚果产量和籽仁产量分别提高6.3%、13.3%和7.7%、16.5%.表明大小行种植有助于扩大光合面积,提高净光合速率,增加干物质积累量,同时缓解花生植株个体与群体间的矛盾,延缓衰老,从而提高麦套花生产量.

Objective: P53 gene mutation is a critical factor that affects many tumors including B-cell lymphoma. Regardless, it remains unclear how p53 mutations cause tumorigenesis. This study aimed to assess the relationship between glycine decarboxylase (GLDC) and p53-mutated B-cell lymphoma. Methods: Point mutations in human lymphoma cells were detected via the PCR-SSCP method. In addition, GLDC amounts in SU-DHL-9 and SU-DHL-1 cells were evaluated by quantitative real-time PCR (qRTPCR) and immunoblotting at the gene and protein levels, respectively. GLDC silencing was performed via siRNA technology in SU-DHL-1 cells and confirmed by western blot. In established mouse models of SUDHL-1 and SU-DHL-9 B-cell lymphoma, GLDC gene (qRT-PCR) and protein (immunoblotting) expression levels were assessed. Results: We found that SU-DHL-9 had no point mutations, and SU-DHL-1 and SU-DHL-8 cells revealed one-point mutation each. SU-DHL-1 cells exhibited increased GLDC mRNA and protein expression levels, while SU-DHL-9 exhibited markedly reduced amounts of GLDC protein in the siRNA group, compared with the blank- and negative-control groups. Animal experiments revealed higher GLDC gene and protein expression levels in SU-DHL-1-induced mouse lymphoma. Conclusion: Human B-cell lymphoma experiments revealed higher GLDC protein amounts in human Bcell lymphoma cells in the P53-positive group, compared with the P53-negative counterparts. Our research supports a direct relationship between GLDC expression and p53 gene-mutated B-cell lymphoma. Providing targets for new drugs.

We recalculate the modes of the magnetohydrodynamics (MHD) waves in the MHD model (Shi, Zhang & Li 2014) of the kilohertz quasi-periodic oscillations (kHz QPOs) in neutron star low mass X-ray binaries (NS-LMXBs), in which the compressed magnetosphere is considered. A method on pointby- point scanning for every parameter of a normal LMXBs is proposed to determine the wave number in a NS-LMXB. The dependence of the twin kHz QPO frequencies on accretion rates ( DOt(M) ) is obtained with the wave number and magnetic field (B?) determined by our method. Based on the MHD model, a new explanation of the parallel tracks, i.e. the slowly varying effective magnetic field leads to the shift of parallel tracks in a source, is presented. In this study, we obtain a simple power-law relation between the kHz QPO frequencies and Dot(M) /B^2 ? in those sources. Finally, we study the dependence of kHz quasi-periodic oscillation frequencies on the spin, mass and radius of a neutron star. We find that the effective magnetic field, the spin, mass and radius of a neutron star lead to the parallel tracks in different sources., 27 pages, 8 figures, accepted for publication in MNRAS

The effects of different irrigation regimes on photosynthesis, plant growth, water use efficiency (WUE), and grain yield in winter wheat were examined in a common garden with rainout shelter during 2013-2014 and 2014-2015 growing seasons. The experiment consisted of two irrigation timings, jointing stage (J) and anthesis (F), and three irrigation levels, 0, 37.5 and 75 mm, which generated nine irrigation combinations, i.e. J试验于2013—2014和2014—2015年连续2个生长季在自动控制干旱棚内的隔离池中进行,拔节期设3个灌水梯度,灌水量分别为0(J

We have performed population synthesis calculation on the formation of binaries containing a black hole (BH) and a neutron star (NS) in the Galactic disk. Some of important input parameters, especially for the treatment of common envelope evolution, are updated in the calculation. We have discussed the uncertainties from the star formation rate of the Galaxy and the velocity distribution of NS kicks on the birthrate ($ \sim 0.6-13 \rm\, Myr^{-1}$) of BH/NS binaries. From incident BH/NS binaries, by modelling the orbital evolution duo to gravitational wave radiation and the NS evolution as radio pulsars, we obtain the distributions of the observable parameters such as the orbital period, eccentricity and pulse period of the BH/pulsar binaries. We estimate that there may be $\sim 3-80 $ BH/pulsar binaries in the Galactic disk and around 10\% of them could be detected by the Five-hundred-meter Aperture Spherical radio Telescope., Comment: 5 pages, 4 figures, 1 table, accepted for publication in MNRAS Letters

A large fraction of black hole low-mass X-ray binaries (BHLMXBs) are in short period orbits, which require strong orbital angular momentum loss during the previous evolutionary stage. Ivanova (2006) put forward the possibility that some of the BHLMXBs may harbour pre-main-sequence (MS) donor stars, in order to explain the Li-overabundances in three BHLMXBs. In this work we investigate the evolution of low-mass pre-MS stars in binaries with a BH companion. We calculate the evolution of the spin and orbital periods, the stellar radius and the Roche-lobe radius during the pre-MS stage with the stellar evolution code MESA. We find that, because of the relatively slow rotation of the pre-MS star after the common envelope evolution and the long turnover time in the pre-MS stars, tidal torque is not always able to synchronize the pre-MS star, so the spin periods are generally longer than the orbital periods. Mass transfer can occur only for stars with mass larger than $\sim 1.2M_\odot$, which experience expansion due to nuclear reaction after the Hayashi contraction phase. The effective temperatures and orbital periods of these systems do not match the observations of BHLMXBs. Our results show that the observed BHLMXBs with lithium overabundances are unlikely to host pre-main sequence donor stars., Comment: 10 pages, 12 figures, accepted by MNRAS

We employ the supernova fallback disk model to simulate the spin evolution of isolated young neutron stars (NSs). We consider the submergence of the NS magnetic fields during the supercritical accretion stage and its succeeding reemergence. It is shown that the evolution of the spin periods and the magnetic fields in this model is able to account for the relatively weak magnetic fields of central compact objects and the measured braking indices of young pulsars. For a range of initial parameters, evolutionary links can be established among various kinds of NS sub-populations including magnetars, central compact objects and young pulsars. Thus, the diversity of young NSs could be unified in the framework of the supernova fallback accretion model., Comment: 16 pages, 7 figures, 9 Oct. 2018 accepted by RAA

Several black hole low-mass X-ray binaries (BHLMXBs) show very fast orbital shrinkage, which is difficult to understand in the standard picture of the LMXB evolution. Based on the possible detection of a circumbinary (CB) disk in A0620-00 and XTE J1118+480, we investigate the influence of the interaction between a CB disk and the inner binary and calculate the evolution of the binary using the Modules for Experiments in Stellar Astrophysics. We consider two cases for the CB disk formation in which it is fed by mass loss during single outburst or successive outbursts in the LMXB. We show that when taking reasonable values of the initial mass and the dissipating time of the disk, it is possible to explain the fast orbital shrinkage in the BHLMXBs without invoking high mass transfer rate., Comment: 17 pages, 9 figures, accepted by ApJ

The mean white dwarf (WD) mass in the Galactic bulge cataclysmic variables (CVs) was measured by applying the the shock temperature-WD mass correlation of magnetic cataclysmic variables (mCVs) to the Galactic Bulge X-ray Emission (GBXE) spectra. However, the resulting mean WD mass is lower than that of the local CVs. This discrepancy could be explained by the dominating sources in the GBXE are non-mCVs instead of mCVs. In this work, we conduct an thorough investigation on the X-ray spectra of local DNe from \suzaku\ archives, and derive semi-empirical correlations between the shock temperature $T_{\rm max}$, the flux ratio of \fec\ to \feb\ lines, and WD mass for quiescent, non-magnetic CVs. By applying these correlations to the GBXE, we derive the average WD mass of CVs in the Galactic bulge to be $0.81\pm 0.07M_\odot$. This value is consistent with previous optical measurements of WD mass in local CVs., Comment: 11 pages, 4 figures, accepted for publication in The Astrophysical Journal

Observations of the ultrastructural morphology of leaf segments of D. officinale with or without P. ultimum infection were made using light microscopy, scanning electron microscopy and transmission electron microscopy. FITC labelling was used to mark cellulose before and after infection by the pathogenic fungus, and observations were performed with a confocal laser-scanning microscope. The results showed that after infection by P. ultimum, the mycelia pierced the leaf tissue of D. officinale through the stomata of the guard cells gradually and changed into structures resembling penetration pegs under microscopy and SEM observations. The appressorium was observed to adhere to the stoma. Furthermore, the fluorescence intensity of cellulose labelled with FITC was much lower in D. officinale leaves infected by P. ultimum than in healthy leaves. Soft rot disease in D. officinale infection with P. ultimum might be related to direct penetration into the cell walls of the plant and the cellulases secreted by the pathogen, which partly contributed to step-by-step degradation of the cell walls of the host plant.

In the Drosophila melanogaster compound eye, myosin-5 (DmM5) plays two distinct roles in response to light stimulation: transport of pigment granules to the rhabdomere base to decrease light exposure and transport of rhodopsin-bearing vesicles to the rhabdomere base to compensate for the rhodopsin loss during light exposure. However, little is known of how the motor function of DmM5 is regulated at the molecular level. In the present study, we overexpressed DmM5 in Sf9 insect cells and investigated its regulation using purified proteins. We found that the actin-activated ATPase activity of DmM5 is significantly lower than that of the truncated DmM5 having the C-terminal globular tail domain (GTD) deleted, indicating that the GTD is the inhibitory domain. The actin-activated ATPase activity of DmM5 is significantly activated by micromolar levels of calcium. DmM5 associates with pigment granules and rhodopsin-bearing vesicles through cargo-binding proteins Lightoid (Ltd) and dRab11 respectively. We found that GTP-bound dRab11, but not Ltd, significantly activates DmM5 actin-activated ATPase activity. Moreover, we identified Gln1689 in the GTD as the critical residue for the interaction with dRab11 and activation of DmM5 motor function by dRab11. Based on those results, we propose that DmM5-dependent transport of pigment granules is directly activated by light-induced calcium influx and the DmM5-dependent transport of rhodopsin-bearing vesicle is activated by active GTP-bound dRab11, whose formation is stimulated by light-induced calcium influx. * CaM, : calmodulin; CC, : coiled coil; dCaM, : Drosophila calmodulin; DmM5, : Drosophila myosin-5; DmM5-FL, : full-length DmM5; DmM5-1IQ, : DmM5 containing the motor domain and IQ1; DmM5-motor, : DmM5 containing the motor domain only; GEF, : guanine-nucleotide-exchange factor; GTD, : C-terminal globular tail domain of DmM5; GTPγS, : guanosine 5′-[γ-thio]triphosphate tetralithium salt; HMM, : heavy meromyosin; Ltd, : lightoid; Mlc-C, : Drosophila cytoplasmic myosin light chain; Myo5, : myosin-5; RT, : reverse transcription; RTW, : rhabdomere terminal web; Sm-849, : recombinant smooth muscle myosin S1

Summary Fusarium head blight (FHB) caused by Fusarium graminearum is a devastating disease of cereal crops worldwide. Recently, a novel fungicide JS399-19 has been launched into the marketplace to manage FHB. It is compelling that JS399-19 shows highly inhibitory activity towards some Fusarium species, but not to other fungi, indicating that it is an environmentally compatible fungicide. To explore the mode of action of this species-specific compound, we conducted a whole-genome transcript profiling together with genetic and biochemical assays, and discovered that JS399-19 targets the myosin I of F. graminearum (FgMyo1). FgMyo1 is essential for F. graminearum growth. A point mutation S217L or E420K in FgMyo1 is responsible for F. graminearum resistance to JS399-19. In addition, transformation of F. graminearum with the myosin I gene of Magnaporthe grisea, the causal agent of rice blast, also led to JS399-19 resistance. JS399-19 strongly inhibits the ATPase activity of the wild-type FgMyo1, but not the mutated FgMyo1S217L/E420K. These results provide us a new insight into the design of species-specific antifungal compounds. Furthermore, our strategy can be applied to identify novel drug targets in various pathogenic organisms.

In this paper, we prove the Hamilton differential Harnack inequality for positive solutions to the heat equation of the Witten Laplacian on complete Riemannian manifolds with the $CD(-K, m)$-condition, where $m\in [n, \infty)$ and $K\geq 0$ are two constants. Moreover, we introduce the $W$-entropy and prove the $W$-entropy formula for the fundamental solution of the Witten Laplacian on complete Riemannian manifolds with the $CD(-K, m)$-condition and on compact manifolds equipped with $(-K, m)$-super Ricci flows., To appear in Journal of Functional Analysis. This paper is an improved version of a part of our previous preprint [14] (arxiv:1412.7034, version1 (22 December 2014) and version 2 (7 February 2016))

In this paper, we prove the Li-Yau type Harnack inequality and Hamilton type dimension free Harnack inequality for the heat equation $\partial_t u=Lu$ associated with the time dependent Witten Laplacian on complete Riemannian manifolds equipped with a variant of the $(K, m)$-super Perelman Ricci flows and the $K$-super Perelman Ricci flows., To appear in the Special Issue of the Asian Journal of Mathematics in honor of Prof. N. Mok's 60th birthday

For inspecting welding seams of large-scale equipment such as storage tanks and spherical tanks, it usually cost much manpower and material, while automated testing robot can achieve fast and accurate detection. Because X-ray Flat Panel Detector is dependent on specialized automated equipment, it can greatly enhance X-ray inspection technology in large storage tanks that applying the Mecanum Omnidirectional Mobile Robot into automated weld detection. In this paper, an X-ray Flat Panel Detector based wall-climbing robotic system is developed for intelligent detecting of welding seams. The robot system consists of two Mecanum vehicles equipped with either a Flat Panel Detector or an X -ray generator and climbing on both side of the tank wall. Inspection robot can carry detector stably with reliable suction force and adapt to different surfaces. To let the X-ray Flat Panel Detector work properly, laser vision tracking system is used to ensure synchronous operation of the two robots. Some experiment was conducted and reported.

The discovery of the ultraluminous X-ray pulsar M82 X-2 has stimulated lively discussion on the nature of the accreting neutron star. In most of the previous studies the magnetic field of the neutron star was derived from the observed spin-up/down rates based on the standard thin, magnetized accretion disk model. However, under super-Eddington accretion the inner part of the accretion disk becomes geometrically thick. In this work we consider both radiation feedback from the neutron star and the sub-Keplerian rotation in a thick disk, and calculate the magnetic moment - mass accretion rate relations for the measured rates of spin change. We find that the derived neutron star's dipole magnetic field depends the maximum accretion rate adopted, but is likely $\lesssim 10^{13}$ G. The predicted accretion rate change can be used to test the proposed models by comparison with observations., ApJ, 838, 98 (2017)

It is generally thought that an ultracompact X-ray binary is composed with a neutron star and a helium white dwarf donor star. As one of the most compact binaries, 4U 1820-303 in globular cluster NGC 6624 was predicted an orbital-period derivative at a rate of $\dot{P}/P\sim1.1\times10^{-7}$ ${\rm yr^{-1}}$ if the mass transfer is fully driven by gravitational radiation. However, the recent analysis of the 16 ${\rm yr}$ data from \textit{Rossi X-ray Timing Explorer} and other historical records yielded a negative orbital-period derivative in the past $35$ yr. In this work, we propose an evolutionary circumbinary (CB) disk model to account for this anomalous orbital-period derivative. 4U 1820-30 was known to undergo superbust events caused by runaway thermal nuclear burning on the neutron star. We assume that for a small fraction of the superbursts, part of the ejected material may form a CB disk around the binary. If the recurrence time of such superbursts is $\sim10,000$ yr and $\sim10$% of the ejected mass feeds a CB disk, the abrupt angular-momentum loss causes a temporary orbital shrink, and the donor's radius and its Roche-lobe radius do not keep in step. Driven by mass transfer and angular-momentum loss, the binary would adjust its orbital parameters to recover a new stable stage. Based on the theoretical analysis and numerical simulation, we find that the required feed mass at the CB disk is approximately $\sim 10^{-8}$ ${\rm M_{\odot}}$., 7 pages, 4 figures, accepted for publication by ApJ

Timing analysis provides information about the dynamics of matter accreting on to neutron stars and black holes, and hence is crucial for studying the physics of the accretion flow around these objects. It is difficult, however, to associate the different variability components with each of the spectral components of the accretion flow. We apply several new methods to two Rossi X-ray Timing Explorer observations of the black hole binary GRS 1915+105 during its heartbeat state to explore the origin of the X-ray variability and the interactions of the accretion-flow components. We offer a promising window into the disc--corona interaction through analysing the formation regions of the disc aperiodic variabilities with different time-scales via comparing the corresponding transition energies of the amplitude-ratio spectra. In a previous paper, we analysed the Fourier power density as a function of energy and frequency to study the origin of the aperiodic variability, and combined that analysis with the phase lag as a function of frequency to derive a picture of the disc--corona interaction in this source. We here, for the first time, investigate the phase lag as a function of energy and frequency, and display some interesting details of the disc--corona interaction. Besides, the results from the shape of amplitude-ratio spectrum and from several other aspects suggest that the quasi-periodic oscillation originates from the corona., Comment: 12 pages, 7 figures

We carry out a dedicated study of 3XMM J181923.7$-$170616\ with an approximate pulsation period of 400~s using the XMM-Newton and Swift observations spanning across nine years. We have refined the period of the source to 407.904(7) s (at epoch MJD 57142) and determined a period derivative limit of $\dot{P}{\leq} 5.9\pm 5.4\times 10^{-9} s s^{-1}$ ($1\sigma$). The source radiates hard, persistent X-ray emission during the observation epochs, which is best described by an absorbed \powerlaw\ model ($\Gamma \sim 0.2$--0.8) plus faint Fe lines at 6.4 keV and 6.7 keV. The X-ray flux revealed a variation within a factor of 2, along with a spectral hardening as the flux increased. The pulse shape is sinusoid-like and the spectral properties of different phases do not present significant variation. The absorption N$_H$ $\sim 1.3\times 10^{22} cm^{-2}$ is similar to the total Galactic hydrogen column density along the direction, indicating that it is a distant source. A search for the counterpart in optical and near-infrared surveys reveals a low mass K-type giant, while the existence of a Galactic OB supergiant is excluded. A symbiotic X-ray binary is the favored nature of 3XMM J181923.7$-$170616 and can essentially explain the low luminosity of ${2.78\times 10^{34} d_{10}^{2} erg s^{-1}}$, slow pulsation, hard X-ray spectrum, and possible K3~III companion. An alternative explanation of the source is a persistent Be/X-ray binary with a companion star no earlier than B3-type., Comment: 15 pages, 7 figures, Published in the Astrophysical Journal

In this paper, we prove the characterization of the $(K, \infty)$-super Perelman Ricci flows by various functional inequalities and gradient estimate for the heat semigroup generated by the Witten Laplacian on manifolds equipped with time dependent metrics and potentials. As a byproduct, we derive the Hamilton type dimension free Harnack inequality on manifolds with $(K, \infty)$-super Perelman Ricci flows. Based on a new second order differential inequality on the Boltzmann-Shannon entropy for the heat equation of the Witten Laplacian, we introduce a new $W$-entropy quantity and prove its monotonicity for the heat equation of the Witten Laplacian on complete Riemannian manifolds with the $CD(K, \infty)$-condition and on compact manifolds with $(K, \infty)$-super Perelman Ricci flows. Our results characterize the $(K, \infty)$-Ricci solitons and the $(K, \infty)$-Perelman Ricci flows. We also prove a second order differential entropy inequality on $(K, m)$-super Ricci flows, which can be used to characterize the $(K, m)$-Ricci solitons and the $(K, m)$-Ricci flows. Finally, we give a probabilistic interpretation of the $W$-entropy for the heat equation of the Witten Laplacian on manifolds with the $CD(K, m)$-condition., Comment: We remove Section 5 from the previous version and add two new results in Section 5. arXiv admin note: text overlap with arXiv:1412.7034

In this survey paper, we give an overview of our recent works on the study of the $W$-entropy for the heat equation associated with the Witten Laplacian on super-Ricci flows and the Langevin deformation on Wasserstein space over Riemannian manifolds. Inspired by Perelman's seminal work on the entropy formula for the Ricci flow, we prove the $W$-entropy formula for the heat equation associated with the Witten Laplacian on $n$-dimensional complete Riemannian manifolds with the $CD(K, m)$-condition, and the $W$-entropy formula for the heat equation associated with the time dependent Witten Laplacian on $n$-dimensional compact manifolds equipped with a $(K, m)$-super Ricci flow, where $K\in \mathbb{R}$ and $m\in [n, \infty]$. Furthermore, we prove an analogue of the $W$-entropy formula for the geodesic flow on the Wasserstein space over Riemannian manifolds. Our result recaptures an important result due to Lott and Villani on the displacement convexity of the Boltzmann-Shannon entropy on Riemannian manifolds with non-negative Ricci curvature. To better understand the similarity between above two $W$-entropy formulas, we introduce the Langevin deformation of geometric flows on the cotangent bundle over the Wasserstein space and prove an extension of the $W$-entropy formula for the Langevin deformation. Finally, we make a discussion on the $W$-entropy for the Ricci flow from the point of view of statistical mechanics and probability theory., Comment: Survey paper. Submitted to Science China Mathematics. arXiv admin note: text overlap with arXiv:1604.02596, arXiv:1706.07040

The transport and localization of organelles within a eukaryotic cell are dependent on a complex network of protein filaments called the cytoskeleton and the associated proteins, including actin filaments and myosins. Myosin is a molecular motor which has ATPase activity and is able to convert the energy from ATP into mechanical movement along actin filaments. To transport cargo efficiently and to prevent the futile hydrolysis of ATP, the motor activity of myosin must be tightly regulated. In the past two decades, considerable progress has been achieved in understanding new myosins and regulatory mechanism of myosin motors. This chapter will present a general view of myosin family and focus on the structure, function, and regulation of three myosins, i.e., smooth muscle myosin-2, myosin-5, and myosin-19.

Basing on the existed theory, the paper built the evaluation model of innovation performance for high-tech enterprise. By analysis of investigation data, the evaluation indexes were preliminary screened. Finally the evaluation index system of innovation performance was proved to be solid reliability and validity through confirmatory factor analysis. The verified evaluation model and index system by quantitative research in the paper provided theoretical basis and methods for innovation performance management of high-tech enterprise, which was beneficial for their promotion of innovation ability and laying foundation for innovation development.

In order to solve the problem of transforming high-quality idea into users' needs, a process model obtaining user demand for fuzzy front end was proposed, which was applied to product innovation design process of pneumatic butterfly valve. This process model covered the key businesses, such as market analysis of the goal, needs analysis, idea analysis, needs evaluation and needs determination, etc. Needs characteristic of user has been discussed in detail. Three kinds of need patterns of demand pull, technology-driven and hybrid form have been analyzed. Pointed out the hierarchical needs structure, function structure diagram and technology roadmap are the key technologies of acquiring user demand.

A safety evaluation index system regarding to the current safety situation of large recreation facilities in China is established. 13 secondary standard items are built by considerring human factor, equipment factor, environment factor and management factor. The existing safety evaluation of large recreation facilities are conducted by qualitative evaluation methods with highly fuzziness. The evaluation results are uncertain. After the network training, a safety evaluation model based on BP neural network is built. It can reduce the subjectivity of qualitative evaluation effectively with more scientific and objective results. Through the model based on BP neural network, the present safety situation of one large amusement facility is evaluated. The evaluation result is consistent with the actual situation. The method based on BP neural network in the paper provides a new method for safety evaluation of large recreation facilities.

© 2016, National Academy of Sciences. All rights reserved. The motor function of vertebrate myosin-5a is inhibited by its tail in a Ca2+-dependent manner. We previously demonstrated that the calmodulin (CaM) bound to the first isoleucine-glutamine (IQ) motif (IQ1) of myosin-5a is responsible for the Ca2+-dependent regulation of myosin-5a. We have solved the crystal structure of a truncated myosin-5a containing the motor domain and IQ1 (MD-IQ1) complexed with Ca2+-bound CaM (Ca2+-CaM) at 2.5-Å resolution. Compared with the structure of the MD-IQ1 complexed with essential light chain (an equivalent of apo-CaM), MD-IQ1/Ca2+-CaM displays large conformational differences in IQ1/CaM and little difference in the motor domain. In the MD-IQ1/Ca2+-CaM structure, the N-lobe and the C-lobe of Ca2+-CaM adopt an open conformation and grip the C-terminal and the N-terminal portions of the IQ1, respectively. Remarkably, the interlobe linker of CaM in IQ1/Ca2+-CaM is in a position opposite that in IQ1/apo-CaM, suggesting that CaM flip-flops relative to the IQ1 during the Ca2+ transition. We demonstrated that CaM continuously associates with the IQ1 during the Ca2+ transition and that the binding of CaM to IQ1 increases Ca2+ affinity and substantially changes the kinetics of the Ca2+ transition, suggesting that the IQ1/CaM complex functions as an intact Ca2+ sensor responding to distinct calcium signals.

Using archival {\it Chandra} observations with a total effective exposure of 734 ks, we derive an updated catalog of point sources in the massive globular cluster Terzan 5. Our catalog covers an area of $58.1\, \rm arcmin^{2}$ ($R\leq 4.3 \, \rm arcmin$) with 489 X-ray sources, and more than $75\%$ of these sources are first detected in this cluster. We find significant dips in the radial distribution profiles of X-ray sources in Terzan 5, with the projected distance and width of the distribution dips for bright ($L_{X} \gtrsim 9.5\times 10^{30} {\rm\ erg\ \,s^{-1}}$) X-ray sources are larger than that of the faint ($L_{X} \lesssim 9.5\times 10^{30} {\rm\ erg\ \,s^{-1}}$) sources. By fitting the radial distribution of the X-ray sources with a"generalized King model", we estimated an average mass of $1.48\pm0.11\,M_{\odot}$ and $1.27\pm0.13\,M_{\odot}$ for the bright and faint X-ray sources, respectively. These results are in agreement with that observed in 47 Tuc, which may suggest a universal mass segregation effect for X-ray sources in GCs. Compared with 47 Tuc, we show that the two-body relaxation timescale of Terzan 5 is much smaller, but its dynamical age is significantly younger than 47 Tuc. These features suggest that the evolution of Terzan 5 is not purely driven by two-body relaxation, and tidal stripping effect also plays an important role in accelerating the dynamical evolution of this cluster., Comment: 20 pages, 3 tables and 7 figures, accepted for publication in ApJ

Previous X-ray observations toward the Nuclear Star Cluster (NSC) at the Galactic center have discovered thousands of point sources, most of which were believed to be cataclysmic variables (CVs), i.e., a white dwarf (WD) accreting from a low-mass companion. However, the population properties of these CVs remain unclear, which otherwise contain important information about the evolutionary history of the NSC. In this work we utilize ultradeep archival \textit{Chandra} observations to study the spectral properties of the NSC CVs, in close comparison with those in the Solar vicinity. We find that the NSC CVs have strong Fe XXV and Fe XXVI lines (both of which show equivalent widths $\sim200-300$ eV), indicating metal-rich companions. Moreover, their Fe XXVI to Fe XXV line flux ratio is used to diagnose the characteristic white dwarf mass ($M_{\rm WD}$) of NSC CVs. The results show that the CVs with $L_{\rm 2-10 keV}>6\times10^{31}$ erg s$^{-1}$ have a mean $M_{\rm WD}$ of $\sim0.6/1.0\,M_{\odot}$ if they are magnetic/non-magnetic CVs; while those with $L_{\rm 2-10 keV}$ between $1-6\times10^{31}$ erg s$^{-1}$ have a mean $M_{\rm WD}$ of $\sim0.8/1.2\,M_{\odot}$ if they are magnetic/non-magnetic CVs. All these \textit{Chandra}-detected CVs collectively contribute $\sim$30-50\% of the unresolved 20-40 keV X-ray emission from the NSC. The CV population with massive (i.e., $M_{\rm WD}\sim1.2M_{\odot}$) WDs have not been observed in the Solar vicinity or the Galactic bulge, and they might have been formed via dynamical encounters in the NSC., 16 pages, 1 Table, 4 Figures, accepted by the Astrophysical Journal

The central compact object 1E 161348$-$5055 in the supernova remnant RCW 103 has a spin period $\sim 6.67$ hr, making it the slowest isolated pulsar. It is believed that a supernova fallback disk is required to spin down the neutron star to the current spin period within a few $10^3$ yr. The mass of the fallback disk around newborn neutron stars can provide useful information on the supernova processes and the possible detection limit with optical/infrared observations. However, it is controversial how massive the disk is in the case of 1E 161348$-$5055. In this work we simulate the spin evolution of a magnetar that is driven by the interaction between the disk and the star's magnetic field. Compared with previous studies, we take into account various critical conditions that affect the formation and evolution of the fallback disk. Our calculation shows that we can reproduce the extremely slow spin of 1E 161348$-$5055 when taking the initial disk mass $M_{\rm d} \sim 10^{-7} M_{\odot}$ and the neutron star magnetic field $B\geq 5 \times 10^{15}$ G. This implies that 1E 161348$-$5055 may be a magnetar with very special initial parameters. However, if future observations reveal more objects like 1E 161348$-$5055, then stringent constraints can be obtained on the supernova fallback., published in ApJ

The accretion-induced collapse (AIC) of a white dwarf in a binary with a nondegenerate companion can sometimes lead to the formation of a rapidly rotating and highly magnetized neutron star (NS). The spin-down of this NS can drive a powerful pulsar wind (PW) and bring out some detectable multi-wavelength emissions. On the one hand, the PW can evaporate the companion in a few days to form a torus surrounding the NS. Then, due to the blockage of the PW by the torus, a reverse shock can be formed in the wind to generate intense hard X-rays. This emission component disappears in a few weeks' time, after the torus is broken down at its inner boundary and scoured into a very thin disk. On the other hand, the interaction between the PW with an AIC ejecta can lead to a termination shock of the wind, which can produce a long-lasting soft X-ray emission component. In any case, the high-energy emissions from deep inside the system can be detected only after the AIC ejecta becomes transparent for X-rays. Meanwhile, by absorbing the X-rays, the AIC ejecta can be heated effectively and generate a fast-evolving and luminous ultraviolet (UV)/optical transient. Therefore, the predicted hard and soft X-ray emissions, associated by an UV/optical transient, provide a clear observational signature for identifying AIC events in current and future observations (e.g., AT 2018cow)., 7 pages, 6 figures

Using archival {\it Chandra} observations with a total exposure of 510 ks, we present an updated catalog of point sources for Globular Cluster 47 Tucanae. Our study covers an area of $\sim 176.7$ arcmin$^{2}$ (i.e., with $R\lesssim7.5\arcmin$) with 537 X-ray sources. We show that the surface density distribution of X-ray sources in 47 Tuc is highly peaked in cluster center, rapidly decreases at intermediate radii, and finally rises again at larger radii, with two distribution dips at $R\sim 100\arcsec$ and $R\sim 170\arcsec$ for the faint ($L_{X}\lesssim 5.0\times 10^{30} {\rm\ erg\,s^{-1}}$) and bright ($L_{X}\gtrsim 5.0\times 10^{30} {\rm\ erg\,s^{-1}}$) groups of X-ray sources, separately. These distribution features are similar to those of Blue Straggler Stars (BSS), where the distribution dip is located at $R\sim 200\arcsec$ \citep{ferraro2004}. By fitting the radial distribution of each group of sources with a "generalized King model", we estimated an average mass of $1.51\pm0.17\ M_{\odot}$, $1.44\pm0.15\ M_{\odot}$ and $1.16\pm0.06\ M_{\odot}$ for the BSS, bright and faint X-ray sources, respectively. These results are consistent with the mass segregation effect of heavy objects in GCs, where more massive objects drop to the cluster center faster and their distribution dip propagates outward further. Besides, the peculiar distribution profiles of X-ray sources and BSS are also consistent with the mass segregation model of binaries in GCs, which suggests that in addition to the dynamical formation channel, primordial binaries are also a significant contributor to the X-ray source population in GCs., 19 pages, 7 figures 3 tables, accepted for publication in ApJ