A new constant-pressure molecular dynamics method for finite system

In this letter, by writing the volume as a function of coordinates of atoms, we present a new constant-pressure molecular dynamics method with parameters free. This method is specially appropriate for the finite system in which the periodic boundary condition does not exist. Simulations on the carbon nanotube and the Ni nanoparticle clearly demonstrate the validity of the method. By using this method, one can easily obtain the equation of states for the finite system under the external pressure.Comment: RevTex, 5 pages, 3 figures, submitted to Phys. Rev. Let

Reciprocal interactions between olfactory receptor axons and olfactory nerve glia cultured from the developing moth Manduca sexta

AbstractIn olfactory systems, neuron–glia interactions have been implicated in the growth and guidance of olfactory receptor axons. In the moth Manduca sexta, developing olfactory receptor axons encounter several types of glia as they grow into the brain. Antennal nerve glia are born in the periphery and enwrap bundles of olfactory receptor axons in the antennal nerve. Although their peripheral origin and relationship with axon bundles suggest that they share features with mammalian olfactory ensheathing cells, the developmental roles of antennal nerve glia remain elusive. When cocultured with antennal nerve glial cells, olfactory receptor growth cones readily advance along glial processes without displaying prolonged changes in morphology. In turn, olfactory receptor axons induce antennal nerve glial cells to form multicellular arrays through proliferation and process extension. In contrast to antennal nerve glia, centrally derived glial cells from the axon sorting zone and antennal lobe never form arrays in vitro, and growth-cone glial-cell encounters with these cells halt axon elongation and cause permanent elaborations in growth cone morphology. We propose that antennal nerve glia play roles similar to olfactory ensheathing cells in supporting axon elongation, yet differ in their capacity to influence axon guidance, sorting, and targeting, roles that could be played by central olfactory glia in Manduca

Gender, Family and Career in the Era of Boundarylessness: Determinants and Effects of Intra- and Inter-organizational Mobility

Changes in patterns of long-term employment make understanding the determinants of different career forms increasingly important to careers research. At the same time, the rise of dual-earner families demands greater attention to the ways in which gender and family characteristics shape careers than has been paid by traditional research. This paper addresses these issues, examining the determinants and consequences of intra-organizational and inter-organizational mobility, using a sample of employees from dual-earner couples. We find significant gender differences in these different types of career mobility, and in the effect of family relations on different forms of mobility. Women experience more inter-organizational mobility, while men experience more intra-organizational mobility. Having more children positively influences men’s intra-organizational mobility, but increases interorganizational mobility for women. Marital instability increases intra-organizational mobility among women, but has no effect among men. Each form of mobility has distinctive effects on objective and subjective indicators of career success for both men and women. Moving between organizations tends to depress earnings, but has no effect on how successful people feel in their careers. Job changes within an organization increase earnings, but have a negative effect on perceived success

Microstructure of nanocrystalline diamond powders studied by powder diffractometry

High resolution x-ray diffraction peaks of diamond nanosize powders of nominal sizes ranging from 5 to 250 nm were analyzed and provided information on grain structure, average size of crystallites, and concentration of dislocations. Selected samples were heat treated at 1670 K at pressures 2.0 and 5.5 GPa or had surface modified by outgassing, heat treatment at vacuum conditions, and by controlled adsorption of gases. The apparent lattice parameter method was applied to characterize the structure of a shell-core model of nanosize particles. The multiple whole profile fitting provided information on crystallite sizes and density of dislocations. Population of dislocations increased with applied pressure, while strain and interplanar distances in the surface layers decreased. Adsorption of foreign gases on the grain surface modified the structure of the surface layers but did not affect dislocations near the center of the grains

​Postdigital citizen science: mapping the field

This paper provides a brief overview of citizen science, attending to its tensions and possibilities. We acknowledge the creative potential of citizen science for expanding and diversifying public participation in knowledge production and dissemination, and we also draw attention to its contradictions. We point to emerging postdigital tensions as new technologies and vast public databases are increasingly becoming cornerstones of citizen science. We discuss how postdigital citizen science operates in the context of knowledge capitalism while aiming at its transformation and highlight three key challenges for postdigital citizen science: the challenge of technology, the challenge of political economy, and the challenge of participation. Different postdigital challenges cannot be separated from each other, so we call for a deep reimagination and reconfiguration of citizen science in and for the postdigital condition. We start this reimagination by asking three questions: What is postdigital citizen science? Who (or what!) is the postdigital citizen scientist? How to conduct postdigital citizen science

Chlamydia trachomatis Infection, Immunity, and Pregnancy Outcome

Chlamydia trachomatis can ascend from the cervix to the fallopian tubes and survive for long periods of time without causing symptoms. The immune response to infection clears the extracellular organisms but leads to development of a persistent intracellular infection. Repeated cycles of productive infection and persistence eventually induce tubal occlusion and infertility. Persistently infected cells continue to synthesize the chlamydial 60 kD heat shock protein (hsp60). Immunity to conserved regions of hsp60 may result in autoimmunity to human hsp60. Expression of hsp60 by the embryo and decidua during early pregnancy may reactivate hsp60-sensitized lymphocytes, disturb pregnancy-induced immune regulatory mechanisms, and lead to immune rejection of the embryo. Due to this mechanism women with tubal infertility who are sensitized to the human hsp60 may have a decreased probability of successful outcome after undergoing in vitro fertilization and embryo transfer

A Mechanism-Based Explanation of the Institutionalization of Semantic Technologies in the Financial Industry

Part 3: Creating Value through ApplicationsInternational audienceThis paper explains how the financial industry is solving its data, risk management, and associated vocabulary problems using semantic technologies. The paper is the first to examine this phenomenon and to identify the social and institutional mechanisms being applied to socially construct a standard common vocabulary using ontology-based models. This standardized ontology-based common vocabulary will underpin the design of next generation of semantically-enabled information systems (IS) for the financial industry. The mechanisms that are helping institutionalize this common vocabulary are identified using a longitudinal case study, whose embedded units of analysis focus on central agents of change—the Enterprise Data Management Council and the Object Management Group. All this has important implications for society, as it is intended that semantically-enabled IS will, for example, provide stakeholders, such as regulators, with better transparency over systemic risks to national and international financial systems, thereby mitigating or avoiding future financial crises