Formation Mechanism and Binding Energy for Body-Centred Regular Tetrahedral Structure of Li5

The formation mechanism for the body-centred regular tetrahedral structure of Li5 cluster is proposed. The curve of the total energy versus the separation R between the nucleus at the centre and nuclei at the apexes for this structure of Li5 has been calculated by using the method of Gou＇s modified arrangement channel quantum mechanics （MACQM）, The result shows that the curve has a minimal energy of-37.2562 a.u. at R =14.5α0. When R approaches infinity the total energy of five lithium atoms has the value of-37.1401 a.u. So the binding energy of Li5 with respect to five lithium atoms is the difference of 0.1161 a.u. for the above two energy values. Therefore the binding energy per atom for Li5 is 0.023 22 a.u., or 0.632 eV, which is greater than the binding energy per atom of 0.453 eV for Li2 and the binding energy per atom of 0.494 eV for Li3 calculated previously by us. This means that the Li3 cluster may be formed stably in a body-centred regular tetrahedral structure with a greater binding energy.

Psychosocial determinants of irritable bowel syndrome

From a pure motor disorder of the bowel,in the past few years,irritable bowel syndrome (IBS) has become a multifactorial disease that implies visceral hypersensitivity,alterations at the level of nervous and humoral communications between the enteric nervous system and the central nervous system,alteration of the gut microflora,an increased intestinal permeability and minimum intestinal inflammation.Psychological and social factors can interfere with the communication between the central and enteric nervous systems,and there is proof that they are involved in the onset of IBS and influence the response to treatment and outcome.There is evidence that abuse history and stressful life events are involved in the onset of functional gastrointestinal disorders.In order to explain clustering of IBS in families,genetic factors and social learning mechanisms have been proposed.The psychological features,such as anxiety,depression as well as the comorbid psychiatric disorders,health beliefs and coping of patients with IBS are discussed in relation to the symptoms and outcome.

Hybridizing artificial bee colony with biogeography-based optimization for constrained mechanical design problems

A novel hybrid algorithm named ABC-BBO, which integrates artificial bee colony(ABC) algorithm with biogeography-based optimization(BBO) algorithm, is proposed to solve constrained mechanical design problems. ABC-BBO combined the exploration of ABC algorithm with the exploitation of BBO algorithm effectively, and hence it can generate the promising candidate individuals. The proposed hybrid algorithm speeds up the convergence and improves the algorithm's performance. Several benchmark test functions and mechanical design problems are applied to verifying the effects of these improvements and it is demonstrated that the performance of this proposed ABC-BBO is superior to or at least highly competitive with other population-based optimization approaches.

CARPAL TUNNEL SYNDROME：ETIOLOGICAL，CLINICAL AND ELECTROPHYSIOLOGICAL ASPECTS OF 262 CASES

Two hundred and sixty-two patients with carpal tunnel syndrome (CTS) were analyzed retrospectively. Results showed that middle-and older-age women were more apt to have CTS than men, and that the dominant hand was more frequently affected. Hormonal changes , repetitive and forceful movements, awkward positions of hand and wrist, and other factors may be associated with CTS. Typical clinical manifestations include pain and paresthesia in the median nerve territory, worsening at night or in the early morning , and being relieved by shaking the hand. Although the patients may localize the discomfort beyond the territory, sensory changes are variable and not entirely reliable. Conduction abnormalities often appeared selectively in the median nerve distal to the wrist in CTS. If the patient who is clinically suggestive of CTS shows normal conduction with conventional methods, palmar stimulation and inching technique is recommended. The diagnosis of CTS requires confirmation of illness history, symptoms and signs with objective electrodiagnostic tests.

Does landscape structure contribute to the long-term maintenance of generalized parasitism in cowbirds?

Unlike most brood parasites, several species of cowbird (Molothrus) are generalists that parasitize multiple host species across their range and within the same communities; likewise, there is little evidence that individuals within a population specialize on host species. This situation has variously been attributed to the recency of cowbird evolution (the 'evolutionary lag' hypothesis) or to hidden costs of rejection by hosts (the 'equilibrium' hypothesis). Both hypotheses have some support as cowbirds are indeed a relatively young clade compared with more specialized cuckoos and cowbirds are capable of sophisticated behaviors such as retaliation against rejection ('mafia' behaviors) that would select for acceptance of cowbird eggs. Nevertheless, many species in the Americas have evolved specialized defenses against cowbird parasitism, almost all of which live in more open habitats (e. g., grasslands, shrublands, riparian strips), which indicates that coevolutionary processes can operate in ways that select for host defenses in spite of cowbird counterdefenses. We propose that the structure of landscapes in North America may explain why forest-nesting birds lack defenses against parasitism and reinforce the long-term maintenance of generalized brood parasitism in cowbirds. Because cowbirds require open habitats in which to feed, they are rare or absent in large forest tracts, which dominate much of the forest cover of the Americas. These tracts act as 'source habitats' that produce surplus young that recolonize populations in smaller, fragmented forest patches in which rates of both cowbird parasitism and nest predation are very high ('sink' habitats). Evolution of antiparasite adaptations would be very slow in this situation because most hosts are produced in areas where there is little or no cowbird parasitism. In addition, the interplay of host breeding dispersal, source-sink metapopulation dynamics, and fragmented forest habitat could further deter the evolution of host defenses against parasitism. Therefore, as long as large forest tracts remain widespread in North America, most forest birds will likely continue to lack defenses against cowbird parasitism, guaranteeing a steady supply of na ve hosts in forest habitats, even in fragmented landscapes. This situation will, in turn, favor host generalist cowbirds that actively avoid more open habitats in favor of parasitizing forest bird communities. These forest communities may also act as source populations for cowbirds, which might pump surplus generalist cowbirds into more open habitats further slowing the coevolutionary process. As long as large forest tracts are a common part of the landscape, generalist parasitism may persist indefinitely.

Reproductive traits of the gray ratsnake Ptyas korros from three geographically distinct populations

Abstract We collected gravid gray rat snakes Ptyas korros from three geographically distinct populations in China, Chenzhou （CZ）, Jiangshan （JS） and Dinghai （DH）, to study geographical variation in female reproductive traits. Egg-laying dates differed among the three populations such that at the most northern latitude egg-laying was latest, and earliest at the most southern latitutde. Clutch size, clutch mass, egg mass, egg shape, within clutch variability in egg sizes and relative clutch mass differed among the three populations, whereas post-oviposition body mass did not. Except for egg-laying date, none of the traits examined varied in a geographically continuous trend. CZ and DH females, although separated by a distance of approximately 1100 km as the crow flies, were similar in nearly all traits examined. JS females were distinguished from CZ and DH females by their higher fecundity （clutch size）, greater reproductive output （clutch mass） and more rounded eggs. Our data do not validate the prediction that larger offspring should be produced in colder localities. The absence of an egg size-number trade-off in each of the three populations presumably suggests that P. korros is among species where eggs are well optimized for size within a population.

A possible family of Ni-based high temperature superconductors

We suggest that a family of Ni-based compounds, which contain [Ni_2M_2O]~2à(M = chalcogen) layers with an antiperovskite structure constructed by mixed-anion Ni complexes, Ni M_4O_2, can be potential high temperature superconductors(high-Tc) upon doping or applying pressure. The layer structures have been formed in many other transitional metal compounds such as La_2B_2Se_2O_3(B = Mn, Fe, Co). For the Ni-based compounds, we predict that the parental compounds host collinear antiferromagnetic states similar to those in iron-based high temperature superconductors. The electronic physics near Fermi energy is controlled by two egd-orbitals with completely independent in-plane kinematics. We predict that the superconductivity in this family is characterized by strong competition between extended s-wave and d-wave pairing symmetries.

Qualitative analysis for a Wolbachia infection model with diffusion

We consider a reaction-diffusion model which describes the spatial Wolbachia spread dynamics for a mixed population of infected and uninfected mosquitoes. By using linearization method, comparison principle and Leray-Schauder degree theory, we investigate the influence of diffusion on the Wolbachia infection dynamics.After identifying the system parameter regions in which diffusion alters the local stability of constant steadystates, we find sufficient conditions under which the system possesses inhomogeneous steady-states. Surprisingly,our mathematical analysis, with the help of numerical simulations, indicates that diffusion is able to lower the threshold value of the infection frequency over which Wolbachia can invade the whole population.

THE DYNAMICAL BEHAVIOR OF NON-SMOOTH SYSTEM WITH IMPULSIVE CONTROL STRATEGIES

Non-smooth system including impulsive strategies at both fixed and unfixed times are analyzed. For the model with fixed impulsive effects, the global stability of pest eradi- cation periodic solution and the dominance of dynamic behavior are investigated. This indicates that the model with fixed moments has the potential to protect the natural enemies from extinction, but under some conditions may also serve to extinction of the pest. The second model is constructed according to the practices of IPM, that is, when the pest population reaches the economic injury level, a combination of biological, cultural, and chemical tactics that reduce pests to tolerable levels is used. Numerical investigations imply that there are several different types of periodic solutions and their maximum amplitudes are always less than the given economic threshold. The results also show that the time series at which the IPM strategies are applied are quite complex, which means that the application and realization of IPM in practice are very difficult.

A platform of digital brain using crowd power

A powerful platform of digital brain is proposed using crowd wisdom for brain research,based on the computational artificial intelligence model of synthesis reasoning and multi-source analogical generating.The design of the platform aims to make it a comprehensive brain database,a brain phantom generator,a brain knowledge base,and an intelligent assistant for research on neurological and psychiatric diseases and brain development.Using big data,crowd wisdom,and high performance computers may significantly enhance the capability of the platform.Preliminary achievements along this track are reported.