Paraoxonase gene polymorphisms and haplotype analysis in a stroke population

Peer reviewedPublisher PD

A More Accurate Generalized Gradient Approximation for Solids

We present a new nonempirical density functional generalized gradient approximation (GGA) that gives significant improvements for lattice constants, crystal structures, and metal surface energies over the most popular Perdew-Burke-Ernzerhof (PBE) GGA. The new functional is based on a diffuse radial cutoff for the exchange-hole in real space, and the analytic gradient expansion of the exchange energy for small gradients. There are no adjustable parameters, the constraining conditions of PBE are maintained, and the functional is easily implemented in existing codes.Comment: 5 pages, corrected the errors of the sublimation energy of Ih ic

Revealing ensemble state transition patterns in multi-electrode neuronal recordings using hidden Markov models

In order to harness the computational capacity of dissociated cultured neuronal networks, it is necessary to understand neuronal dynamics and connectivity on a mesoscopic scale. To this end, this paper uncovers dynamic spatiotemporal patterns emerging from electrically stimulated neuronal cultures using hidden Markov models (HMMs) to characterize multi-channel spike trains as a progression of patterns of underlying states of neuronal activity. However, experimentation aimed at optimal choice of parameters for such models is essential and results are reported in detail. Results derived from ensemble neuronal data revealed highly repeatable patterns of state transitions in the order of milliseconds in response to probing stimuli

Livestock Producers and Researchers - A Case Study of an Effective Partnership

The Sustainable Grazing Systems Programme (SGS) ran from 1996-2002 with 11 regional producer committees (Regional Producer Network - Simpson et al., 2003) and 6 research sites (National Experiment Andrew & Lodge, 2003) distributed throughout the high rainfall zone of temperate Australia. Each regional committee had a core of producers, with invited scientists and extension practitioners and a paid facilitator. The chair was always a producer and rotated annually. Each regional committee conducted a number of paddock-sized demonstrations of improved grazing management practices on a number of farms within the themes; grazing management and weeds, high input systems, innovative grazing methods for production and the SGS adoption process. Each demonstration was on a producer\u27s property assisted by a local management committee with objective data collected by the regional facilitator. The National research sites investigated the effects of grazing management on sustainable livestock production through five themes; water, nutrients, pastures, animals and biodiversity. Producers had a significant input into the design of the National Experiment and each site had a local advisory committee

Thermal and electrical modelling of polymer cored BGA interconnects

Polymer cored BGA/CSP balls have been proposed as a more reliable alternative to solid solder balls for demanding application environments. Their potential advantages are dependant on their increased compliance compared with a solid solder ball, thereby reducing the level of stress imposed on the solder joints during exposure to cyclic thermal loads and impacts. The latter is of particular importance for hand held products assembled using lead free solders, which are much more brittle than traditional tin-lead alloys, but this may also be important for harsh environment applications where tinlead solders are still being used, such as in aerospace and defence electronics applications. The increased compliance of a polymer cored ball may reduce the requirement for underfilling of components in hand held products, and allow adoption of BGA/CSP for safety critical applications in harsh environments. Such polymer cored interconnects are however likely to provide a reduced thermal and electrical conductivity and it is important to ensure any such effects do not impact upon the thermal and electrical performance of the product. This paper utilises analytical and computational modelling techniques to achieve an understanding of the effect of conductor particle geometry and properties on thermal and electrical performance. Such models offer a route to appropriate materials selection for the polymer spheres and their conductive coatings, and for establishing optimum design parameters such as ball diameter, conductive coating thickness, solder pad diameter, and solder volumes. The results confirm that the introduction of polymer cored BGA balls will result in some increases in thermal and electrical resistance, but that these changes will have minor impacts on the overall performance of products

Does no-tillage mitigate the negative effects of harvest compaction on soil pore characteristics in Northeast China?

Optimizing tillage management is one way to reduce the risk of soil compaction due to traffic load in Northeast China. In this study, we aimed to examine the responses of precompression stress (σpc), compression index (Cc), pore morphology (>30 µm), air-filled porosity (εa60), air permeability at matric potential of − 60 hPa (ka60) and saturated hydraulic conductivity (Ks) to harvest traffic on soil from two contrasting tillage practices using a 10-yr old field experiment. After the crop was harvested with a combine harvester, undistributed soil cores were collected in the 0–10 and 10–20 cm layers from non-traffic and traffic zones of no-tillage (NT) and moldboard plough (MP) plots. In the non-traffic zone, the MP management showed greater total porosity (εtotal), εa60 and macroporosity (εX-ray) than the NT. There were no differences in pore connectivity, mean pore size and ka60 of the 0–10 cm layer and in Ks of the 0–20 cm layer between the two tillage practices, however, more biopores were observed under NT. Harvest traffic showed no significant effects on NT soil. In the MP plots, the εtotal, εX-ray, and pore connectivity, were decreased and pores larger than 0.15 mm were preferentially compacted. As a result of traffic, MP soil displayed lower ka60 in the 0–20 cm layer and lower εX-ray and connectivity in the 10–20 cm layer. In the NT management, the pore system had greater water and air conduction efficiencies and stable properties. Thus, compared to MP, NT can mitigate the negative effects of harvest compaction on soil in Northeast China

Electrical method of monitoring percolation and abrasion of conducting spheres due to shear flow of a dense suspension in a narrow gap

This letter describes a method for studying the behavior of rigid particles in a dense suspension when they are forced into contact during flow within a narrow gap. The particles form transient percolating networks spanning the boundary walls, and will be crushed together. The method involves measuring the dc electrical resistance across the gap. The suspension e.g., solder paste consists of electrically conducting particles suspended in an insulating fluid. The electrical resistance drops when the particles are in contact with each other and the walls, and the insulating films on the surface of the conductors have been broken through. The results show a dramatic change in behavior as the ratio of gap to particle diameter is varied

An overlooked mechanism underlying the attenuated temperature response of soil heterotrophic respiration

Biogeochemical reactions occurring in soil pore space underpin gaseous emissions measured at macroscopic scales but are difficult to quantify due to their complexity and heterogeneity. We develop a volumetric-average method to calculate aerobic respiration rates analytically from soil with microscopic soil structure represented explicitly. Soil water content in the model is the result of the volumetric-average of the microscopic processes, and it is nonlinearly coupled with temperature and other factors. Since many biogeochemical reactions are driven by oxygen (O2) which must overcome various resistances before reaching reactive microsites from the atmosphere, the volumetric-average results in negative feedback between temperature and soil respiration, with the magnitude of the feedback increasing with soil water content and substrate quality. Comparisons with various experiments show the model reproduces the variation of carbon dioxide emission from soils under different water content and temperature gradients, indicating that it captures the key microscopic processes underpinning soil respiration. We show that alongside thermal microbial adaptation, substrate heterogeneity and microbial turnover and carbon use efficiency, O2 dissolution and diffusion in water associated with soil pore space is another key explanation for the attenuated temperature response of soil respiration and should be considered in developing soil organic carbon models