4,174 research outputs found

    Independent trapping and manipulation of microparticles using dexterous acoustic tweezers

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    An electronically controlled acoustic tweezer was used to demonstrate two acoustic manipulation phenomena: superposition of Bessel functions to allow independent manipulation of multiple particles and the use of higher-order Bessel functions to trap particles in larger regions than is possible with first-order traps. The acoustic tweezers consist of a circular 64-element ultrasonic array operating at 2.35MHz which generates ultrasonic pressure fields in a millimeter-scale fluid-filled chamber. The manipulation capabilities were demonstrated experimentally with 45 and 90-lm-diameter polystyrene spheres. These capabilities bring the dexterity of acoustic tweezers substantially closer to that of optical tweezers

    Semiparametric approach to characterize unique gene expression trajectories across time

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    BACKGROUND: A semiparametric approach was used to identify groups of cDNAs and genes with distinct expression profiles across time and overcome the limitations of clustering to identify groups. The semiparametric approach allows the generalization of mixtures of distributions while making no specific parametric assumptions about the distribution of the hidden heterogeneity of the cDNAs. The semiparametric approach was applied to study gene expression in the brains of Apis mellifera ligustica honey bees raised in two colonies (A. m. mellifera and ligustica) with consistent patterns across five maturation ages. RESULTS: The semiparametric approach provided unambiguous criteria to detect groups of genes, trajectories and probability of gene membership to groups. The semiparametric results were cross-validated in both colony data sets. Gene Ontology analysis enhanced by genome annotation helped to confirm the semiparametric results and revealed that most genes with similar or related neurobiological function were assigned to the same group or groups with similar trajectories. Ten groups of genes were identified and nine groups had highly similar trajectories in both data sets. Differences in the trajectory of the reminder group were consistent with reports of accelerated maturation in ligustica colonies compared to mellifera colonies. CONCLUSION: The combination of microarray technology, genomic information and semiparametric analysis provided insights into the genomic plasticity and gene networks linked to behavioral maturation in the honey bee

    A response to “Likelihood ratio as weight of evidence: a closer look” by Lund and Iyer

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    Recently, Lund and Iyer (L&I) raised an argument regarding the use of likelihood ratios in court. In our view, their argument is based on a lack of understanding of the paradigm. L&I argue that the decision maker should not accept the expert’s likelihood ratio without further consideration. This is agreed by all parties. In normal practice, there is often considerable and proper exploration in court of the basis for any probabilistic statement. We conclude that L&I argue against a practice that does not exist and which no one advocates. Further we conclude that the most informative summary of evidential weight is the likelihood ratio. We state that this is the summary that should be presented to a court in every scientific assessment of evidential weight with supporting information about how it was constructed and on what it was based

    Sputtered NiO_x Films for Stabilization of p^+n-lnP Photoanodes for Solar-Driven Water Oxidation

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    A photoanode protection strategy using a multifunctional NiO_x coating is presented. The ransparency/antireflectivity, low electrochromism, conduction of holes, corrosion protection, and active electrocatalysis for water-oxidation half-reaction are described

    Treatment with pyrophosphate inhibits uremic vascular calcification

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    Pyrophosphate, which may be deficient in advanced renal failure, is a potent inhibitor of vascular calcification. To explore its use as a potential therapeutic, we injected exogenous pyrophosphate subcutaneously or intraperitoneally in normal rats and found that their plasma pyrophosphate concentrations peaked within 15 min. There was a single exponential decay with a half-life of 33 min. The kinetics were indistinguishable between the two routes of administration or in anephric rats. The effect of daily intraperitoneal pyrophosphate injections on uremic vascular calcification was then tested in rats fed a high-phosphate diet containing adenine for 28 days to induce uremia. Although the incidence of aortic calcification varied and was not altered by pyrophosphate, the calcium content of calcified aortas was significantly reduced by 70%. Studies were repeated in uremic rats given calcitriol to produce more consistent aortic calcification and treated with sodium pyrophosphate delivered intraperitoneally in a larger volume of glucose-containing solution to prolong plasma pyrophosphate levels. This maneuver significantly reduced both the incidence and amount of calcification. Quantitative histomorphometry of bone samples after double-labeling with calcein indicated that there was no effect of pyrophosphate on the rates of bone formation or mineralization. Thus, exogenous pyrophosphate can inhibit uremic vascular calcification without producing adverse effects on bone

    STRATEGIC AGRIBUSINESS OPERATION REALIGNMENT IN THE TEXAS PRISON SYSTEM

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    Mathematical programming-based systems analysis is used to examine the consequences of alternative operation configuration for the agricultural operations within the Texas Department of Criminal Justice. Continuation versus elimination of the total operation as well as individual operating departments are considered. Methodology includes a firm systems operation model combined with capital budgeting and an integer programming based investment model. Results indicate the resources realize a positive return as a whole, but some enterprises are not using resources profitably. The integer investment model is found to be superior for investigating whether to continue multiple interrelated enterprises.agribusiness, enterprise selection, mathematical programming, optimal enterprise organization, Agribusiness,

    Approaching the Numerical Aperture of Water - Immersion Lithography at 193nm

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    As immersion nanolithography gains acceptance for next generation device applications, experimental data becomes increasingly important. The behavior of resist materials, fluids, coatings, sources, and optical components in the presence of a water immersion media presents conditions unique compared to convention “dry” lithography. Several groups have initiated fundamental studies into the imaging, fluids, contamination, and integration issues involved with water immersion lithography at 193nm. This paper will present the status and results of the next stage of the development efforts carried out at RIT. The status of two systems are presented; a small field projection microstepper utilizing a 1.05 catadioptric immersion objective lens and a 0.50 to 1.26NA interferometric immersion exposure system based on a compact Talbot prism lens design. Results of the fundamental resolution limits of resist materials and of imaging optics are presented. Additionally, an exploration into the benefits of increasing the refractive index of water is addressed through the use of sulfate and phosphate additives. The potential of KrF, 248nm immersion lithography is also presented with experimental resist imaging results
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