An eccentric binary millisecond pulsar in the galactic plane

Binary pulsar systems are superb probes of stellar and binary evolution and the physics of extreme environments. In a survey with the Arecibo telescope, we have found PSR J1903+0327, a radio pulsar with a rotational period of 2.15 milliseconds in a highly eccentric (e = 0.44) 95-day orbit around a solar mass (M(middle dot in circle)) companion. Infrared observations identify a possible main-sequence companion star. Conventional binary stellar evolution models predict neither large orbital eccentricities nor main-sequence companions around millisecond pulsars. Alternative formation scenarios involve recycling a neutron star in a globular cluster, then ejecting it into the Galactic disk, or membership in a hierarchical triple system. A relativistic analysis of timing observations of the pulsar finds its mass to be 1.74 +/- 0.04 M solar symbol, an unusually high value.     

Absorption features in the x-ray spectrum of an ordinary radio pulsar

The vast majority of known nonaccreting neutron stars (NSs) are rotation-powered radio and/or γ-ray pulsars. So far, their multiwavelength spectra have all been described satisfactorily by thermal and nonthermal continuum models, with no spectral lines. Spectral features have, however, been found in a handful of exotic NSs and were thought to be a manifestation of their unique traits. Here, we report the detection of absorption features in the x-ray spectrum of an ordinary rotation-powered radio pulsar, J1740+1000. Our findings bridge the gap between the spectra of pulsars and other, more exotic, NSs, suggesting that the features are more common in the NS spectra than they have been thought so far.     

A pulsar, the heliosphere, and pioneer 10: probable mimicking of a planet of PSR B1257+12 by solar rotation

Doppler data generated with the Pioneer 10 spacecraft's radio carrier wave between 1987 and 1995 show a 25.3-day periodicity which is related to the solar rotation. The timing data of the pulsar PSR B1257+12 also show a periodicity of 25.34 days, which has been explained as a signature of the pulsar's barycentric motion in response to the existence of a small moon-like object. However, because PSR B1257+12 is located close to the ecliptic and because the timing variations are in the range of microseconds, it is likely that the pulsar signal is affected by the same mechanism acting on the Pioneer 10 Doppler data. Hence, the hypothesized inner planet around PSR B1257+12 is probably an artifact of the heliosphere.     

Discovery of very high energy gamma rays associated with an x-ray binary

X-ray binaries are composed of a normal star in orbit around a neutron star or stellar-mass black hole. Radio and x-ray observations have led to the presumption that some x-ray binaries called microquasars behave as scaled-down active galactic nuclei. Microquasars have resolved radio emission that is thought to arise from a relativistic outflow akin to active galactic nuclei jets, in which particles can be accelerated to large energies. Very high energy gamma-rays produced by the interactions of these particles have been observed from several active galactic nuclei. Using the High Energy Stereoscopic System, we find evidence for gamma-ray emission of >100 gigaelectron volts from a candidate microquasar, LS 5039, showing that particles are also accelerated to very high energies in these systems.     

一种基于B+树的RFID抗冲突算法

针对二进制树形算法冲突集合分裂速度慢、标签分裂不均匀问题,提出一种基于B+树的RFID抗冲突算法.本算法将冲突集合分裂成一个3阶的B+树,即将每次发生冲突的集合分裂成3个子集,从而加快冲突集合的分裂速度,冲突集合相当于B+树的中间节点,每个子集分别对应于一个关键码,叶子节点或只包含一个标签或为一个空集合.为了防止集合分裂的不均匀,引入合适的hash函数,使集合均匀分裂.仿真实验表明,B+算法减少了标签冲突的发生,缩短了标签识别延时,提高了识别性能.     

Hepatitis associated with hepatitis B virus in broilers

Infection by hepatitis B virus(HBV) results in acute and chronic liver damages in humans. Liver products of broilers as a primary food consumed in our daily life have a close connection with public health. The prevalence of the virus in livers and serum of broilers is of great significance, owning to the potential transmission between chickens and humans. Liver tissues and serum samples were tested to investigate the prevalence of hepatitis B virus infection in slaughtered broilers, for expression of HBV antigens and antibodies. The distribution and positive rate of hepatitis B surface antigen(HBs Ag), hepatitis B core antigen(HBc Ag) and hepatitis B e antigen(HBe Ag) in liver samples were examined using immunohistochemistry. HBs Ag was mainly located in the cytoplasm of hepatocytes with a positivity of 81.61% whereas HBe Ag and HBc Ag were primarily located in the nucleus of hepatocytes with a positivity of 40.13 and 49.10%, respectively. Enzyme-linked immunosorbent assay(ELISA) analysis of serum for HBV serological markers demonstrated a high prevalence of hepatiits B surface antibody(HBsA b, 54.91%) and hepatitis B core antibody(HBcA b, 27.68%), whereas HBeA b, HBsA g and HBeA g were rarely detectable. Classic hepatitis pathological changes, including swollen hepatocytes, focal parenchymal necrosis, lymphocytic infiltration and hyperplasia of fibrous connective tissues were observed using histopathological analysis. Some of the liver samples were found positive for HBV DNA using nested PCR. Sequence comparison confirmed that all sequences shared 97.5–99.3% identity with human HBV strains. These results demonstrated the existence of HBV in livers and serums of broilers. Animals or animal products contaminated with HBV could raise an important public health concern over food safety and zoonotic risk.     

龙麦20小麦品种17+18与7+8亚基近等基因系间品质差异的初步研究

为了解小麦Glu-B1位点HMW-GS 17＋18与7＋8的遗传差异,利用生化标记和连续6次选择性回交的方法将17＋18亚基转移到黑龙江省小麦品种龙麦20中,获得了龙麦20的Glu-B1位点HMW-GS17＋18与7＋8的近等基因系（NILs）。2006年将NILs种植在黑龙江省农业科学院育种研究所的试验田,田间设计采用双列对比排列,4次重复。近等基因系品质分析结果表明,17＋18亚基类型与7＋8亚基类型相比,面筋指数、沉降值、形成时间、稳定时间和断裂时闽等重要的品质参数均有一定程度的提高。在5＋10亚基遗传背景下,Glu-B1位点17＋18亚基对面筋强度仍有一定影响,因此在选育强筋小麦时,17＋18应作为优质亚基予以考虑。     

算子方程(A*)nX+X*An=B的解

设A,B是Hilbert空间H上两个有界线性算子,在A值域为闭的情况下,利用算子矩阵分块技巧研究算子方程(A*)nX+X*An=B的解,得到了该方程有解的充要条件和解的一般形式;特别地,当n=1时,研究了算子方程A*X+X*A=B的正解,给出了该方程有正解的充要条件和正解的一般形式.     

算子方程(A*)nX+X*An=B的解

设A,B是Hilbert空间H上两个有界线性算子,在A值域为闭的情况下,利用算子矩阵分块技巧研究算子方程(A*)nX+X*An=B的解,得到了该方程有解的充要条件和解的一般形式;特别地,当n=1时,研究了算子方程A*X+X*A=B的正解,给出了该方程有正解的充要条件和正解的一般形式.     

Observation of pulsed gamma-rays above 25 GeV from the Crab pulsar with MAGIC

One fundamental question about pulsars concerns the mechanism of their pulsed electromagnetic emission. Measuring the high-end region of a pulsar's spectrum would shed light on this question. By developing a new electronic trigger, we lowered the threshold of the Major Atmospheric gamma-ray Imaging Cherenkov (MAGIC) telescope to 25 giga-electron volts. In this configuration, we detected pulsed gamma-rays from the Crab pulsar that were greater than 25 giga-electron volts, revealing a relatively high cutoff energy in the phase-averaged spectrum. This indicates that the emission occurs far out in the magnetosphere, hence excluding the polar-cap scenario as a possible explanation of our measurement. The high cutoff energy also challenges the slot-gap scenario.     

An iron-regulated ferric reductase associated with the absorption of dietary iron

The ability of intestinal mucosa to absorb dietary ferric iron is attributed to the presence of a brush-border membrane reductase activity that displays adaptive responses to iron status. We have isolated a complementary DNA, Dcytb (for duodenal cytochrome b), which encoded a putative plasma membrane di-heme protein in mouse duodenal mucosa. Dcytb shared between 45 and 50% similarity to the cytochrome b561 family of plasma membrane reductases, was highly expressed in the brush-border membrane of duodenal enterocytes, and induced ferric reductase activity when expressed in Xenopus oocytes and cultured cells. Duodenal expression levels of Dcytb messenger RNA and protein were regulated by changes in physiological modulators of iron absorption. Thus, Dcytb provides an important element in the iron absorption pathway.     

DS18B20在林学气象测量中的应用

根据数字温度传感器DS18B20的单总线的结构特点，利用简单的接口与单片机组成一个多点温度测量系统，给出了用DS18B20和AT89C2051单片机构成的温度测量系统的应用电路和参考程序。     

龙麦20小麦品种中7+8*亚基和17+18亚基近等基因系间的品质差异

 【目的】确定高分子麦谷蛋白亚基17＋18和7+8*间的遗传差异。【方法】利用生化标记和选择性回交（5次）的方法将拥有超量表达的Bx7亚基的加拿大超强筋小麦品种Glenlea的7+8*亚基转移到了小麦品种龙麦20亚基组成为1,17+18,5+10的近等基因系（NILs）中,获得了龙麦20的17+18亚基和7+8*亚基的近等基因系。2005年这对近等基因系被种植在黑龙江农业科学院育种研究所的试验地里,试验设计采用随机取组,6次重复。【结果】品质分析结果表明,7+8*亚基类型的龙麦20与17+18亚基龙麦20类型相比,面粉蛋白质含量提高5%（P =0.012）、干面筋含量增加4%（P =0.018）、湿面筋/干面筋降低2%（P =0.043）、沉降值提高10%（P =0.013）、形成时间提高13%（P=0.258）、稳定时间提高256%（P =0.029）、断裂时间提高86%（P =0.020）、软化度降低35%（P =0.007）。【结论】7+8*亚基对面筋强度有较大的正向影响。     

Coherent soft x-ray generation in the water window with quasi-phase matching

We demonstrate enhanced generation of coherent light in the "water window" region of the soft x-ray spectrum at 4.4 nanometers, using quasi-phase-matched frequency conversion of ultrafast laser pulses. By periodically modulating the diameter of a gas-filled hollow waveguide, the phase mismatch normally present between the laser light and the generated soft x-ray light can be partially compensated. This makes it possible to use neon gas as the nonlinear medium to coherently convert light up to the water window, illustrating that techniques of nonlinear optics can be applied effectively in the soft x-ray region of the spectrum. These results advance the prospects for compact coherent soft x-ray sources for applications in biomicroscopy and in chemical spectroscopy.     

基于DS18B20的温室温度控制系统设计

温室温度监测是控制农作物生长的关键因素,传统温度调节方式已不能满足现代温室高精度、快速采集及响应的要求。进行了基于DS18B20的温室温度控制系统的硬件和软件设计。该温度控制系统具有精度高、抗干扰能力强、经济性好、适合于恶劣环境的现场温度测控、温控范围广等优点。     

20%苄·乙可湿性粉剂在水稻中的残留动态研究

[目的]研究乙草胺在水稻中的消解动态及最终残留量。[方法]通过黑龙江、吉林和湖南2年3地的田间小区试验和气相色谱分析技术,分析乙草胺在水稻上的残留动态,测定最终残留量。[结果]乙草胺在水稻上的半衰期为4.4～8.3d,半衰期较短,属于易降解农药。在有效成分为600和900g/hm^2的剂量条件下,施药1次,测得水稻中乙草胺残留量均低于0.01mg/kg。[结论]综合多方面因素,按照900g/hm^2施药剂量处理,建议我国乙草胺在水稻上的MRL值可暂定为0.02mg/kg,施药次数1次。     

基于传感器DS18B20的温室测温系统设计

介绍了以AT89S52为控制核心,利用数字化温度传感器DS18B20实现温室温度测量的一种方法。论述了系统的硬件组成、各功能部分的电路设计和系统的软件设计,给出了关键功能部分的电路图、单片机的温度测量程序和单片机与上位机的串行通信程序。     

20世纪初民族新闻业的专业主义解读

20世纪初我国民族新闻业者的杰出代表,受西方新闻观念特别是新闻专业主义理念的影响,在社会动荡、历史变革的现实语境中,改变传统的政争至上、政党为本的新闻运作模式,以新闻为本位,以受众为中心,以业界发展为目标,在新闻观念的引进、记者地位的提高、新闻学教育的兴办、新闻思想的形成等诸多方面进行了广泛而有益的尝试。综观这一时期新闻学者的观念、言行及新闻业界的发展轨迹,无不显现出西方新闻专业主义理念如影随行的境象,西方新闻专业主义成为20世纪初民族新闻业得以勃兴的思想源泉。     

Deletion in chromosome 11p associated with a hepatitis B integration site in hepatocellular carcinoma

Hepatitis B virus (HBV), a virus with known carcinogenic potential, integrates into cellular DNA during long-term persistent infection in man. Hepatocellular carcinomas isolated from viral carriers often contain clonally propagated viral DNA integrations. As small chromosomal deletions are associated with several types of carcinomas, the occurrence of chromosomal deletions in association with HBV integration in hepatocellular carcinoma was studied. HBV integration was accompanied by a deletion of at least 13.5 kilobases of cellular sequences in a human hepatocellular carcinoma. The viral DNA integration and deletion of cellular sequences occurred on the short arm of chromosome 11 at location 11p13-11p14. The cellular sequences that were deleted at the site of HBV integration were lost from the tumor cells, leaving only a single copy of the remaining cellular allele.