159 research outputs found

    Bounds and optimisation of orbital angular momentum bandwidths within parametric down-conversion systems

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    The measurement of high-dimensional entangled states of orbital angular momentum prepared by spontaneous parametric down-conversion can be considered in two separate stages: a generation stage and a detection stage. Given a certain number of generated modes, the number of measured modes is determined by the measurement apparatus. We derive a simple relationship between the generation and detection parameters and the number of measured entangled modes.Comment: 6 pages, 4 figure

    Supersymmetric Regularization, Two-Loop QCD Amplitudes and Coupling Shifts

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    We present a definition of the four-dimensional helicity (FDH) regularization scheme valid for two or more loops. This scheme was previously defined and utilized at one loop. It amounts to a variation on the standard 't Hooft-Veltman scheme and is designed to be compatible with the use of helicity states for "observed" particles. It is similar to dimensional reduction in that it maintains an equal number of bosonic and fermionic states, as required for preserving supersymmetry. Supersymmetry Ward identities relate different helicity amplitudes in supersymmetric theories. As a check that the FDH scheme preserves supersymmetry, at least through two loops, we explicitly verify a number of these identities for gluon-gluon scattering (gg to gg) in supersymmetric QCD. These results also cross-check recent non-trivial two-loop calculations in ordinary QCD. Finally, we compute the two-loop shift between the FDH coupling and the standard MS-bar coupling, alpha_s. The FDH shift is identical to the one for dimensional reduction. The two-loop coupling shifts are then used to obtain the three-loop QCD beta function in the FDH and dimensional reduction schemes.Comment: 44 pages, minor corrections and clarifications include

    T-Duality and Penrose limits of spatially homogeneous and inhomogeneous cosmologies

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    Penrose limits of inhomogeneous cosmologies admitting two abelian Killing vectors and their abelian T-duals are found in general. The wave profiles of the resulting plane waves are given for particular solutions. Abelian and non-abelian T-duality are used as solution generating techniques. Furthermore, it is found that unlike in the case of abelian T-duality, non-abelian T-duality and taking the Penrose limit are not commutative procedures.Comment: 16 pages, 4 figures. Discussion on non-abelian T-duality expande

    Monitoring and classification of dimensional faults for automotive body assembly

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    Sudden process changes occurring during automobile body assembly processes will influence the downstream assembly process and the functionality and final appearance of the vehicle. Furthermore, these faults could result in a decreased production rate and an increase in the cost if sudden process changes are so serious that the production line has to be stopped for investigation. Thus, sudden process changes should be detected and eliminated as soon as possible to prevent defective products from being produced and to reduce the cost of repairs/reworks. A monitoring algorithm is developed to detect, classify, and group process changes by analyzing the dimensional data of car bodies. The results of this monitoring algorithm can help diagnose the root causes of variation according to the locations of measurement points, body structure, assembly sequence, and tooling layout. Measurement data obtained from an optical coordinate measuring machine (OCMM) are used to demonstrate the monitoring technique.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45577/1/10696_2005_Article_BF01358905.pd

    De geprotocolleerde Interapy-behandeling van depressie via het internet; resultaten van een gerandomiseerde trial

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    Psychologische behandelingen via internet bieden een nieuwe mogelijkheid voor de geestelijke gezondheidszorg. In samenwerking met de Stichting Mentrum ggz Amsterdam heeft Interapy een behandeling voor depressie via internet opgezet. De behandeling bestaat uit cognitief-gedragstherapeutische interventies, zoals psycho-educatie, schrijfopdrachten, registratie, activatie, het uitdagen van negatieve automatische gedachten en terugvalpreventie. Dit artikel beschrijft de procedure, de behandeling en de resultaten van een vergelijkende studie onder cliënten die matig tot ernstig depressief waren. De cliënten die direct actief werden behandeld (N = 32) verbeterden significant meer dan de cliënten in de psycho-educatieconditie (N = 14). Deze tweede groep kreeg de actieve behandeling ongeveer twaalf weken later. De effecten waren groot. In de actief behandelde groep liet 75 procent van de cliënten klinisch relevante verbetering zien, in de psycho-educatieconditie was dat percentage 36. Uit de follow-up na zes weken bleek dat de verbeteringen standhielden

    Genetic variants in CPA6 and PRPF31 are associated with variation in response to metformin in individuals with type 2 diabetes

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    Metformin is the first-line treatment for type 2 diabetes (T2D). Although widely prescribed, the glucose-lowering mechanism for metformin is incompletely understood. Here, we used a genome-wide association approach in a diverse group of individuals with T2D from the Action to Control Cardiovascular Risk in Diabetes (ACCORD) clinical trial to identify common and rare variants associated with HbA 1c response to metformin treatment and followed up these findings in four replication cohorts. Common variants in PRPF31 and CPA6 were associated with worse and better metformin response, respectively (P < 5 3 10 26 ), and meta-analysis in independent cohorts displayed similar associations with metformin response (P = 1.2 3 10 2 8 and P = 0.005, respectively). Previous studies have shown that PRPF31(+/2) knockout mice have increased total body fat (P = 1.78 3 10 26 ) and increased fasted circulating glucose (P = 5.73 3 10 26 ). Furthermore, rare variants in STAT3 associated with worse metformin response (q <0.1). STAT3 is a ubiquitously expressed pleiotropic transcriptional activator that participates in the regulation of metabolism and feeding behavior. Here, we provide novel evidence for associations of common and rare variants in PRPF31, CPA6, and STAT3 with metformin response that may provide insight into mechanisms important for metformin efficacy in T2D

    Attrition among families of divorce: Patterns in an outpatient psychiatric population

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    The accelerated divorce rate has greatly increased the number of children of divorce. In addition, the children and families of divorce are proportionately overrepresented in populations seeking child guidance and psychiatric services. However, the patterns in the use of such services by these families has been unexamined. In our study we find no differences in the use of outpatient psychiatric services between families where both biological parents are present and families of divorce. A closer look at the divorced families reveals that recently divorced mother-headed families more frequently interrupt both the evaluation and treatment phases of clinic contact. Several clinical patterns are described which help explain the finding and it is suggested that the traditional child guidance model may not be the most suitable intervention modality in working with these families.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44293/1/10591_2004_Article_BF00927093.pd

    Genetic Variants in HSD17B3, SMAD3, and IPO11 Impact Circulating Lipids in Response to Fenofibrate in Individuals With Type 2 Diabetes

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    Individuals with type 2 diabetes (T2D) and dyslipidemia are at an increased risk of cardiovascular disease. Fibrates are a class of drugs prescribed to treat dyslipidemia, but variation in response has been observed. To evaluate common and rare genetic variants that impact lipid responses to fenofibrate in statin-treated patients with T2D, we examined lipid changes in response to fenofibrate therapy using a genomewide association study (GWAS). Associations were followed-up using gene expression studies in mice. Common variants in SMAD3 and IPO11 were marginally associated with lipid changes in black subjects (P < 5 × 10 -6 ). Rare variant and gene expression changes were assessed using a false discovery rate approach. AKR7A3 and HSD17B13 were associated with lipid changes in white subjects (q < 0.2). Mice fed fenofibrate displayed reductions in Hsd17b13 gene expression (q < 0.1). Associations of variants in SMAD3, IPO11, and HSD17B13, with gene expression changes in mice indicate that transforming growth factor-beta (TGF-ÎČ) and NRF2 signaling pathways may influence fenofibrate effects on dyslipidemia in patients with T2D

    Using quantitative descriptive analysis and temporal dominance of sensations analysis as complementary methods for profiling commercial blackcurrant squashes

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    Quantitative descriptive analysis (QDA) is used to describe the nature and the intensity of sensory properties from a single evaluation of a product, whereas temporal dominance of sensation (TDS) is primarily used to identify dominant sensory properties over time. Previous studies with TDS have focused on model systems, but this is the first study to use a sequential approach, i.e. QDA then TDS in measuring sensory properties of a commercial product category, using the same set of trained assessors (n = 11). The main objectives of this study were to: (1) investigate the benefits of using a sequential approach of QDA and TDS and (2) to explore the impact of the sample composition on taste and flavour perceptions in blackcurrant squashes. The present study has proposed an alternative way of determining the choice of attributes for TDS measurement based on data obtained from previous QDA studies, where available. Both methods indicated that the flavour profile was primarily influenced by the level of dilution and complexity of sample composition combined with blackcurrant juice content. In addition, artificial sweeteners were found to modify the quality of sweetness and could also contribute to bitter notes. Using QDA and TDS in tandem was shown to be more beneficial than each just on its own enabling a more complete sensory profile of the products

    DNA and Protein Requirements for Substrate Conformational Changes Necessary for Human Flap Endonuclease-1 Catalyzed Reaction.

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    Human flap endonuclease-1 (hFEN1) catalyzes the essential removal of single-stranded flaps arising at DNA junctions during replication and repair processes. hFEN1 biological function must be precisely controlled, and consequently, the protein relies on a combination of protein and substrate conformational changes as a prerequisite for reaction. These include substrate bending at the duplex-duplex junction and transfer of unpaired reacting duplex end into the active site. When present, 5'-flaps are thought to thread under the helical cap, limiting reaction to flaps with free 5'-termini in vivo. Here we monitored DNA bending by FRET and DNA unpairing using 2-aminopurine exciton pair CD to determine the DNA and protein requirements for these substrate conformational changes. Binding of DNA to hFEN1 in a bent conformation occurred independently of 5'-flap accommodation and did not require active site metal ions or the presence of conserved active site residues. More stringent requirements exist for transfer of the substrate to the active site. Placement of the scissile phosphate diester in the active site required the presence of divalent metal ions, a free 5'-flap (if present), a Watson-Crick base pair at the terminus of the reacting duplex, and the intact secondary structure of the enzyme helical cap. Optimal positioning of the scissile phosphate additionally required active site conserved residues Y40, D181 and R100 and a reacting duplex 5'-phosphate. These studies suggest a FEN1 reaction mechanism where junctions are bound, 5'-flaps are threaded (when present), and finally the substrate is transferred onto active site metals initiating cleavage
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