Transformation of a star into a planet in a millisecond pulsar binary

Millisecond pulsars are thought to be neutron stars that have been spun-up by accretion of matter from a binary companion. Although most are in binary systems, some 30% are solitary, and their origin is therefore mysterious. PSR J1719-1438, a 5.7-millisecond pulsar, was detected in a recent survey with the Parkes 64-meter radio telescope. We show that this pulsar is in a binary system with an orbital period of 2.2 hours. The mass of its companion is near that of Jupiter, but its minimum density of 23 grams per cubic centimeter suggests that it may be an ultralow-mass carbon white dwarf. This system may thus have once been an ultracompact low-mass x-ray binary, where the companion narrowly avoided complete destruction.     

带杠杆千斤顶的设计

带杠杆千斤顶是基于地震、矿难、车祸等场合的救援或自救而自主研发的一种新型、简便、实用、高效的救援装置。由于其构造简单、携带方便,对于空间狭小且地表复杂的救援非常实用,亦可民用或作为工厂维修工具。本文对设计的原理方案、产品优点及使用进行了系统的说明。     

一类生化开关模型的定性分析

本文研究一类生化开关模型其中ｘ≥０，ｙ≥０；ａｉ，ｂｉ，ｃｉ（ｉ＝１，２）为正参数、给出了系统（１）具有开关行为的充要条件．     

Identification of a sex pheromone from a spider

The compounds (R)-3-hydroxybutyric acid and its dimer, (R)-3-[(R)-3-hydroxybutyryloxy]-butyric acid, have been identified as sex pheromones of a spider. These compounds elicit web reduction behavior by males of Linyphia triangularis (Clerck) on the webs of unmated adult females.     

Capture of a single molecule in a nanocavity

We describe a heptameric protein pore that has been engineered to accommodate two different cyclodextrin adapters simultaneously within the lumen of a transmembrane beta barrel. The volume between the adapters is a cavity of approximately 4400 cubic angstroms. Analysis of single-channel recordings reveals that individual charged organic molecules can be pulled into the cavity by an electrical potential. Once trapped, an organic molecule shuttles back and forth between the adapters for hundreds of milliseconds. Such self-assembling nanostructures are of interest for the fabrication of multianalyte sensors and could provide a means to control chemical reactions.     

Development of a receptor on a foreign nerve fiber in a Pacinian corpuscle

When the sensory fiber of a Pacinian corpuscle (in cat mesentery) is transected (at the inferior mesenteric nerve) transduction fails within 30 hours: the nerve ending produces no generator potentials in response to mechanical stimulation. Electrically elicited nerve impulse conduction continues for at least another 18 hours. A transducer mechanism develops on a regenerating nerve fiber when this fiber enters the denervated corpuscle. Such transducer development takes place on myelinated fibers from the inferior mesenteric nerve, which normally supplies corpuscles, as well as on myelinated hypogastric nerve fibers, which normally do not go to corpuscles, including fibers larger than the original corpuscle afferents.     

Conversion of a peroxiredoxin into a disulfide reductase by a triplet repeat expansion

Pathways for the reduction of protein disulfide bonds are found in all organisms and are required for the reductive recycling of certain enzymes including the essential protein ribonucleotide reductase. An Escherichia coli strain that lacks both thioredoxin reductase and glutathione reductase grows extremely poorly. Here, we show that a mutation occurring at high frequencies in the gene ahpC, encoding a peroxiredoxin, restores normal growth to this strain. This mutation is the result of a reversible expansion of a triplet nucleotide repeat sequence, leading to the addition of one amino acid that converts the AhpC protein from a peroxidase to a disulfide reductase. The ready mutational interconversion between the two activities could provide an evolutionary advantage to E. coli.     

一类p-Ginzburg—Landau泛函的C^1,a口收敛

研究了一类p-Ginzburg-Landau（p〉0）模型的渐近性态.通过局部分析的技巧,推出了泛函的正则性估计.在此基础上,利用Euler方程解的正则性估计及渐近行为,得到了极小元的C1,α收敛.     

Discrimination of successiveness: a test of a model of attention

Interpreting attention as a periodic phenomenon, we show its relevance to discriminating the successiveness of signals presented to separate sense modalities. Experiments confirm the expected linear relation between the probability of discriminating pairs of successive from pairs of simultaneous signals and make it possible to infer the period of attention.     

一个具有非自治性扰动的拟线性椭圆方程非平凡解的存在性

利用变量替换和Ekeland变分原理,在R～N上获得了一类具有非自治扰动的拟线性椭同方程非平凡解的存在性结果.

Abstract：

The existence of a nontrivial solution is obtained for a quasilinear elliptic equations on RN with a non-autonomous perturbation by the change of variable and the Ekeland's variational principle.     

Identification of a juvenile hormone-like compound in a crustacean

Juvenile hormone (JH) has central roles in the regulation of insect development and reproduction but has not previously been identified in other arthropod classes. The hemolymph of a crustacean, Libinia emarginata (Leach), has now been analyzed for JH-like compounds. Samples contained 0.003 to 0.030 nanogram of JH III per milliliter and 10 to 50 nanograms of methyl farnesoate per milliliter; methyl farnesoate is a compound structurally related to JH III that has JH bioactivity. Several tissues were examined for synthesis and secretion of JH-like compounds. Of these tissues, only the mandibular organs produced and secreted JH III and methyl farnesoate. However, microchemical analysis revealed that this JH III was racemic, and thus likely an artifactual oxidation product of methyl farnesoate. Secretion of methyl farnesoate was related to reproduction in females, with the highest rates observed in Libinia near the end of the ovarian cycle when oocyte growth and vitellogenesis are greatest. These results indicate that JH-like compounds such as methyl farnesoate have regulatory roles in crustaceans.     

Allergenic component of a liverwort: a sesquiterpene lactone

Frullania spp. (Hepaticae, Jungermanniales) are agents of allergies. Extraction and fractionation of Frullania tamarisci has given, as the only allergenic component isolated, a levorotatory crystalline sutbstance, the structure of which is demonstrated. It is a sesquiterpene lactone. The racemic (+/-) form is isolated from a mixed sample of Frullania tamarisci and Frullania dilatata; the dextrorotatory form, from Frullania dilatata. The observed allergenic properties are shared by some other-sesquiterpene lactones.     

湖南省一种刀腹茧蜂学名的订正

订正湖南省一种刀腹茧蜂暗翅刀腹茧蜂Xiphozele obscuripennis You et Zhou 的学名.     

Rotation of a single molecule within a supramolecular bearing

Experimental visualization and verification of a single-molecule rotor operating within a supramolecular bearing is reported. Using a scanning tunneling microscope, single molecules were observed to exist in one of two spatially defined states laterally separated by 0.26 nanometers. One was identified as a rotating state and the other as an immobilized state. Calculations of the energy barrier for rotation of these two states show that it is below the thermal energy at room temperature for the rotating state and above it for the immobilized state.     

Transformation of a simple plastic into a superhydrophobic surface

Superhydrophobic surfaces are generally made by controlling the surface chemistry and surface roughness of various expensive materials, which are then applied by means of complex time-consuming processes. We describe a simple and inexpensive method for forming a superhydrophobic coating using polypropylene (a simple polymer) and a suitable selection of solvents and temperature to control the surface roughness. The resulting gel-like porous coating has a water contact angle of 160 degrees. The method can be applied to a variety of surfaces as long as the solvent mixture does not dissolve the underlying material.     

Information as a thermodynamic function of a living system

It is suggested to introduce an information term into the Gibbs thermodynamic equation in the case of living systems. The possibility of describing the behavior of organisms by means of such an approach is shown.     

复合微生态制剂在半封闭混养池塘中的应用

在半封闭池塘中混养红鳍东方鲀Fugu rubripes和日本对虾Penaeus japonicus,同时施用复合微生态制剂（每次换水后施用剂量为0.45 g/m3）,对池塘水体中的溶解氧、氨氮、亚硝酸盐氮和化学需氧量进行了监测,并对红鳍东方鲀和日本对虾的成活率和生长情况进行了观察。结果表明：与对照池相比,试验池的溶解氧浓度提高了14.6%,氨氮浓度降低了26.1%,亚硝酸盐氮降低了28.4%,化学需氧量浓度降低了19.8%;与对照池相比,试验池中红鳍东方鲀的体重和成活率分别提高14.3%、6.4%,日本对虾的体长、体重及成活率也分别提高10.3%、15.4%、5.6%。这说明该复合微生态制剂对改善混养池塘水质具有很好的效果,同时对提高红鳍东方鲀和日本对虾的成活率以及促进其生长方面都有很好的作用。