Assessment of different genetic distances in constructing cotton core subset by genotypic values

One hundred and sixty-eight genotypes of cotton from the same growing region were used as a germplasm group to study the validity of different genetic distances in constructing cotton core subset. Mixed linear model approach was employed to unbiasedly predict genotypic values of 20 traits for eliminating the environmental effect. Six commonly used genetic distances(Euclidean,standardized Euclidean,Mahalanobis,city block,cosine and correlation distances) combining four commonly used hierarchical cluster methods(single distance,complete distance,unweighted pair-group average and Ward's methods) were used in the least distance stepwise sampling(LDSS) method for constructing different core subsets. The analyses of variance(ANOVA) of different evaluating parameters showed that the validities of cosine and correlation distances were inferior to those of Euclidean,standardized Euclidean,Mahalanobis and city block distances. Standardized Euclidean distance was slightly more effective than Euclidean,Mahalanobis and city block distances. The principal analysis validated standardized Euclidean distance in the course of constructing practical core subsets. The covariance matrix of accessions might be ill-conditioned when Mahalanobis distance was used to calculate genetic distance at low sampling percentages,which led to bias in small-sized core subset construction. The standardized Euclidean distance is recommended in core subset construction with LDSS method.

The role of endoscopic retrograde cholangiopancreatography in perioperative period of laparoscopic cholecystectomy

Objective: To explore the indications and the value ofendoscopic retrograde cholangiopancreatography(ERCP)in perioperative phase of laparoscopic cholecystecto-my.Methods: From January 1998 to April 1999, a total of1500 consecutive laparoscopic cholecystectomies wereanalyzed. The indications for preoperative group (n=33) included elevated bilirubin level and alkalinephosphatase level, jaundice, pancreatitis, abnormalliver function, dilated bile duct and/or stones on ul-trasound or CT. The indications for postoperativegroup (n=20) included clinical signs or symptoms aswell as common bile duct stones demonstrated by in-traoperative cholangiography.Results: Preoperative ERCP for 32 patients (2.1%)showed abnormalities in 12 (37%). Postoperative ER-CP for 20 patients(1.3%) demonstrated abnormalitiesin 14 (70%). Super-selected criteria for preoperativeERCP would predict more than 66% ductal stones.Endoscopic sphincterectomy and duct stones clearancewere performed in all 16 patients with documentedcommon bile duct stones. The morbidity was confinedin 2 patients with self-limited pancreatitis (3%).Conclusions: Using super-selected creteria to selectpatients for preoperative ERCP can avoid unnecessaryERCP. As soon as postoperative patients have clinicalsigns or symptoms, endoscopic treatment should beperformed.

我国以房养老的研究现状与发展趋势

目的对我国以房养老研究进行文献计量学分析,了解以房养老研究现状与发展趋势。方法计算机检索中国知网、维普、万方和中国生物医学文献数据库关于以房养老的研究,检索时限为建库至2020年12月31日。提取相关研究的作者姓名、单位、发表时间、关键词等资料。利用VOSviewer1.6.9软件对高频关键词进行热点分析和聚类分析,生成可视化密度图和聚类图。结果共纳入1007篇文献。以房养老研究始于2001年,2014年发文量达到高峰(172篇),随后发文量呈下降趋势。高产作者少,作者、机构之间的合作缺乏。1007篇研究共有1708个关键词,仅有30个(1.76%)出现频次大于10次。关键词之间共形成3个明显聚类。新兴关键词有7个,分别为制度构建、影响因素、模式、定价模型、传统观念、社区养老和(养老)保险。结论国内以房养老的研究领域过于广泛且研究尚处探索阶段,未来应加强作者、机构之间的合作。

External photon fields in Fermi bright blazars

The external Compton （EC） model is used to study the high energy emission of some blazars, in which the external photon field is considered to dominate inverse Compton radiation. We explore the properties of the external photon field through analyzing the FERMI LAT bright AGN sample within three months of the start of operations in sky-survey mode. In the sample, assuming the high energy radiation of low synchrotron peaked blazars is from the EC process, we find that the external photon parameter Uext/υext may not be a constant. Calculating synchrotron and inverse Compton luminosity from the quasi-simultaneous broadband spectral energy distributions, we find that they have an approximately linear relation. This indicates that the ratio of external photon and magnetic energy density is a constant in the comoving frame, implying that the Lorentz factor of the emitting blob depends on the external photon field and magnetic field. The result gives a strong constraint on the dynamic jet model.

New Simulations of the X-Ray Spectra and Polarizations of Accretion-disk Corona Systems with Various Geometrical Configurations I.Model Description

Energetic X-ray radiations emitted from various accretion systems are widely considered to be produced by Comptonization in the hot corona.The corona and its interaction with the disk play an essential role in the evolution of the system and are potentially responsible for many observed features.However,many intrinsic properties of the corona are still poorly understood,especially for the geometrical configurations.The traditional spectral fitting method is not powerful enough to distinguish various configurations.In this paper,we intend to investigate the possible configurations by modeling the polarization properties of X-ray radiations.The geometries of the corona include the slab,sphere and cylinder.The simulations are implemented through the publicly available code,Lemon,which can deal with the polarized radiative transfer and different electron distributions readily.The results demonstrate clearly that the observed polarizations are dependent heavily on the geometry of the corona.The slab-like corona produces the highest polarization degrees(PDs),followed by the cylinder and sphere.One of the interesting things is that the PDs first increase gradually and then decrease with the increase of photon energy.For slab geometry,there exists a zero-point where the polarization vanishes and the polarization angle(PA)rotates by 90°.These results may potentially be verified by the upcoming missions for polarized X-ray observations,such as IXPE and e XTP.

The force-free dipole magnetosphere in nonlinear electrodynamics

Quantum electrodynamics(QED)effects may be included in physical processes of magnetar and pulsar magnetospheres with strong magnetic fields.Involving the quantum corrections,Maxwell electrodynamics is modified to nonlinear electrodynamics.In this work,we study the force-free magnetosphere in nonlinear electrodynamics in a general framework.The pulsar equation describing a steady and axisymmetric magnetosphere is derived,which now admits solutions with corrections.We derive the first-order nonlinear corrections to the near-zone dipole magnetosphere in some popular nonlinear effective theories.The field lines of the corrected dipole tend to converge on the rotational axis so that the fields in the polar region are stronger compared to the pure dipole case.

CCD astrometric observations of 2017 VR12, Camillo and Midas

We have observed three near-Earth objects(NEOs), 2017 VR12, Camillo and Midas, during 2018.The observations were made with the 1-m telescope, operated by Yunnan Observatories, over two nights.Their precise astrometric positions are derived from 989 CCD observations. The theoretical positions of asteroids are retrieved from the Jet Propulsion Laboratory(JPL) Horizons System and Institut de M′ecanique C′eleste et de Calcul des ′Eph′em′erides(IMCCE). The positions of three asteroids are measured with respect to stars in the Gaia DR2 star catalog. For 2017 VR12, the means(O-C) of right ascension and declination are -0.090′′and-0.623′′respectively based on the published JPL ephemeris, but the corresponding means(O-C) are 3.122′′and-0.636′′based on the published IMCCE ephemeris. The great difference in declination could be explained by several factors.(1) The degraded CCD images caused by the fast apparent motion of the objects lead to a reduction in positioning accuracy.(2) The poor timing system may introduce systematic errors, especially in the high speed direction.(3) The asteroid may be perturbed by Earth when it approaches the Earth too closely. These astrometric results demonstrate that the centroid centering method can reduce the dispersion of non-Gaussian images as compared with the PSF modeling method.For Camillo and Midas, the astrometric results are consistent based on the two ephemerides. Implementing a high-precision timing system, and analyzing some astronomical effects and geometric distortions in CCD images should be carefully considered in future works.

Transient Phenomena from Gas Erupting Neutron Stars

Starquakes probably occur in rapidly spinning or ultra high field neutron stars. In this article, we argue that highly compressed gas containing electron–positron pairs could evaporate and erupt from inside the neutron star when a crack forms and then heals during a starquake. Under the influence of the existing oscillation modes of the star, the crack may have sufficiently large size and long lifetime. An appropriate amount of gas can erupt into the magnetosphere with relativistic and nearly uniform velocity, producing various transient and bursting phenomena.

The Origin of The Soft X-Ray Excess in the Seyfert 1.5 Galaxy ESO 362-G18

We review the Seyfert 1.5 Galaxy ESO 362-G18 for exploring the origin of the soft X-ray excess.The Warm Corona and Relativistic Reflection models are two main scenarios to interpret the soft X-ray excess in active galactic nuclei at present.We use the simultaneous X-ray observation data of XMM-Newton and Nu STAR on2016 September 24 to perform spectral analysis in two steps.First,we analyze the time-average spectra by using Warm Corona and Relativistic Reflection models.Moreover,we also explore the Hybrid model,Double Reflection model and Double Warm Corona model.We find that both the Warm Corona and Relativistic Reflection models can interpret the time-average spectra well but cannot be distinguished easily based on the time-averaged spectra fit statistics.Second,we add the rms and covariance spectra to perform the spectral analysis with time-average spectra.The result shows that the warm corona could reproduce all of these spectra well.The hot,optical thin corona and neutral distant reflection will increase their contribution with the temporal frequency,meaning that the corona responsible for X-ray continuum comes from the inner compact X-ray region and the neutral distant reflection is made of some moderate scale neutral clumps.

Origin of power-law X-ray emission in the steep power-law state of X-ray binaries

We present a new explanation for the origin of the steep power-law（SPL） state of X-ray binaries.The power-law component of X-ray emission is the synchrotron radiation of relativistic electrons in highly magnetized compact spots orbiting near the inner stable circular orbit of a black hole.It has a hard spectrum that extends to above MeV energies,which is determined by the electron acceleration rate.These photons are then down-scattered by the surrounding plasma to form an observed steep spectrum.We discuss the relevance of the model to high-frequency quasi-periodic oscillations and the extremely high luminosity of the SPL state.

Reanalysis of the RXTE observations of the black-hole candidate XTE J1650-500 in the 2001/2002 outburst

We present the results of the spectral fits made to 59 Rossi X-ray Timing Explorer （RXTE） observations of the Galactic X-Ray Black-Hole Candidate XTE J1650–500 covering the first 30d of its 2001/2002 outburst when the source was in a transition from the hard state to the soft state. The photon spectra can be well fit- ted with a phenomenological model of a power-law/cutoff power-law and a physical model of bulk-motion Comptonization. The spectral properties smoothly evolve away from the hard state and then stay in the soft state. The fitting results of the physical model reveal the peak of the burst had a flux of 2.90 × 10-8 erg cm-2 s-1 in the 2–100 keV energy range and was observed on 2001 Sep. 9; it transitioned to the hard state. The total flux decays by a factor of ～3 as it evolves into the soft state. The photon index Γ increases from ～1.5 in the hard state and stays at ～2.5 in the soft state. We found that the effective area of the high-energy X-ray emission region （the Compton cloud） decreases, i.e. the area of the Compton cloud decreases by a factor of ～23 during the transition from the hard state to the soft state. Combining the new radio and quasi-periodic oscillation studies, the model of total flux in the 2–100 keV energy range, the jet emission and the timing analysis during the state transition, we suggest a possible geometry and evolution for the （jet＋corona＋disk） system, like that proposed by Kalemci et al. based on enhanced lags and peak frequency shift during the transition.

Dependence of low redshift Type Ia Supernovae luminosities on host galaxies

We study the relation between Type Ia Supernovae （SNe Ia） and properties of their host galaxies using a large sample with low redshift. By examining the Hubble residuals of the entire sample from the best-fit cosmology, we show that SNe Ia in passive hosts are brighter than those in star-forming hosts after light curve correction at the 2. 1σ confidence level. We find that SNe Ia in high luminosity hosts are brighter after light-curve correction at the 〉 3σ confidence level. We also find that SNe Ia in large galaxies are brighter after light-curve correction at the ≥2σ confidence level. We demonstrate that the residuals depend linearly on host luminosity at a confidence of 4or or host size at a confidence of 3.3σ.

Ferritin-based nanomedicine for disease treatment

Ferritin is an endogenous protein which is selfassembled by 24 subunits into a highly uniform nanocage structure.Due to the drug-encapsulating ability in the hollow inner cavity and abundant modification sites on the outer surface,ferritin nanocage has been demonstrated great potential to become a multi-functional nanomedicine platform.Its good biocompatibility,low toxicity and immunogenicity,intrinsic tumor-targeting ability,high stability,low cost and massive production,together make ferritin nanocage stand out from other nanocarriers.In this review,we summarized ferritin-based nanomedicine in field of disease diagnosis,treatment and prevention.The different types of drugs to be loaded in ferritin,as well as drug-loading methods were classified.The strategies for site-specific and non-specific functional modification of ferritin were investigated,then the application of ferritin for disease imaging,drug delivery and vaccine development were discussed.Finally,the challenges restricting the clinical translation of ferritin-based nanomedicines were analyzed.

Nanomedicine integrating the lipidic derivative of 5-fluorouracil,miriplatin and PD-L1 si RNA for enhancing tumor therapy

Immunosuppressive microenvironments present critical problems in clinical chemotherapy.To regulate the tumor immune microenvironment for enhancing antitumor effect,a combination of immune checkpoint inhibitors(ICIs)with chemotherapeutics has been applied clinically.In this study,miriplatin(MiPt),the lipidic derivative of 5-fluorouracil(Fu-OA),as well as the programmed death ligand 1(PD-L1)target si RNA(siPD-L1)were integrated into Lip-Pt/Fu@siPD-L1 nanoparticles(NPs)for chemo-immunotherapy.In vitro results showed that Lip-Pt/Fu@siPD-L1 NPs could exhibit effective siRNA gene silencing and promote the phagocytosis of tumor cells by macrophages.Furthermore,in vivo results revealed that LipPt/Fu@siPD-L1 NPs showed significantly higher anti-tumor efficiency than that of the physical mixing of Mi Pt,5-fluorouracil,and Lip@siPD-L1 NPs(delivery of siPD-L1 by liposomes).The best anti-tumor efficiency of Lip-Pt/Fu@siPD-L1 NPs resulted from the synergistic immunotherapeutic effects of Mi Pt and siPD-L1 based on the inhibition of CD47 expression and the downregulation of PD-L1 in tumor cells,which elicited a robust anti-tumor immune response through the activation of macrophage phagocytosis and immune checkpoint inhibition.The Lip-Pt/Fu@siPD-L1 NPs provide a potential strategy for tumor chemo-immunotherapy.

Effect of the scale of quantitative trait data on the representativeness of a cotton germplasm sub-core collection

A cotton germplasm collection with data for 20 quantitative traits was used to investigate the effect of the scale of quantitative trait data on the representativeness of plant sub-core collections.The relationship between the representativeness of a sub-core collection and two influencing factors,the number of traits and the sampling percentage,was studied.A mixed linear model approach was used to eliminate environmental errors and predict genotypic values of accessions.Sub-core collections were constructed using a least distance stepwise sampling(LDSS) method combining standardized Euclidean distance and an unweighted pair-group method with arithmetic means(UPGMA) cluster method.The mean difference percentage(MD),variance difference percentage(VD),coincidence rate of range(CR),and variable rate of coefficient of variation(VR) served as evaluation parameters.Monte Carlo simulation was conducted to study the relationship among the number of traits,the sampling percentage,and the four evaluation parameters.The results showed that the representativeness of a sub-core collection was affected greatly by the number of traits and the sampling percentage,and that these two influencing factors were closely connected.Increasing the number of traits improved the representativeness of a sub-core collection when the data of genotypic values were used.The change in the genetic diversity of sub-core collections with different sampling percentages showed a linear tendency when the number of traits was small,and a logarithmic tendency when the number of traits was large.However,the change in the genetic diversity of sub-core collections with different numbers of traits always showed a strong logarithmic tendency when the sampling percentage was changing.A CR threshold method based on Monte Carlo simulation is proposed to determine the rational number of traits for a relevant sampling percentage of a sub-core collection.