2,821 research outputs found

    Realizing quantum controlled phase-flip gate through quantum dot in silicon slow-light photonic crystal waveguide

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    We propose a scheme to realize controlled phase gate between two single photons through a single quantum dot in slow-light silicon photonic crystal waveguide. Enhanced Purcell factor and beta factor lead to high gate fidelity over broadband frequencies compared to cavity-assisted system. The excellent physical integration of this silicon photonic crystal waveguide system provides tremendous potential for large-scale quantum information processing.Comment: 9 pages, 3 figure

    Use of different tissues of horseshoe crabs Tachypleus gigas for biomonitoring heavy metal bioavailability and contamination in intertidal area of Peninsular Malaysia

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    In this study, female horseshoe crabs Tachypleus gigas were collected from three sampling sites in the west intertidal waters of Peninsular Malaysia. The horseshoe crabs species were analyzed for Cu, Cu, Ni and Zn in the different dissected ten parts namely prosomatic carapace, opisthosomatic carapace, telson, operculum, remaining shells, muscles in the opisthosoma, eggs, gills, digestive tract, and remaining soft tissue. Cu and Zn levels in all the edibles were lower than the max permissible limits of food safety guidelines but Cd concentration of the horseshoe crabs eggs were found to have slightly exceeded the permissibly limits for food safety. Higher bioavailabilities of metals to biomonitor T. gigas were found at populations collected from high anthropogenic site at Kg. Pasir Puteh. This verified the higher metal levels in the tissues of T. gigas were related to the anthropogenic sources of the sampling site

    Self-Dual Conformal Supergravity and the Hamiltonian Formulation

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    In terms of Dirac matrices the self-dual and anti-self-dual decomposition of a conformal supergravity is given and a self-dual conformal supergravity theory is developed as a connection dynamic theory in which the basic dynamic variabes include the self-dual spin connection i.e. the Ashtekar connection rather than the triad. The Hamiltonian formulation and the constraints are obtained by using the Dirac-Bergmann algorithm. PACS numbers: 04.20.Cv, 04.20.Fy,04.65.+

    A Pair of Disjoint 3-GDDs of type g^t u^1

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    Pairwise disjoint 3-GDDs can be used to construct some optimal constant-weight codes. We study the existence of a pair of disjoint 3-GDDs of type gtu1g^t u^1 and establish that its necessary conditions are also sufficient.Comment: Designs, Codes and Cryptography (to appear

    Assessment of surface water quality in the Malaysian coastal waters by using multivariate analyses.

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    Coastal water samples were collected from 20 sampling sites in the southern part of Peninsular Malaysia. Seven physico-chemical parameters were measured directly in-situ while water samples were collected and analysed for 6 dissolved trace metal concentrations. The surface water (0-20 cm) physico-chemical parameters including temperature, salinity, dissolved oxygen (DO), pH, total dissolved solids (TDS), specific conductance (SpC) and turbidity while the dissolved trace metals were Cd, Cu, Fe, Ni, Pb and Zn. The ranges for the physico-chemical parameters were 28.07-35.6ยฐC for temperature, 0.18-32.42 ppt for salinity, 2.20-12.03 mg/L for DO, 5.50-8.53 for pH, 0.24-31.65 mg/L for TDS, 368-49452 ฮผ/cm for SpC and 0-262 NTU for turbidity while the dissolved metals (mg/L) were 0.013-0.147 for Cd, 0.024-0.143 for Cu, 0.266-2.873 for Fe, 0.027-0.651 for Ni, 0.018-0.377 for Pb and 0.032-0.099 for Zn. Based on multivariate analysis (including correlation, cluster and principal component analyses), the polluted sites were found at Kg. Pasir Puteh and Tg. Kupang while Ni and Pb were identified as two major dissolved metals of high variation in the coastal waters. Therefore, water quality monitoring and control of release of untreated anthropogenic wastes into rivers and coastal waters are strongly needed

    Role and development of GLP-1 receptor agonists in the management of diabetes

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    Glucagon-like peptide-1 (GLP-1) is a hormone secreted from enteroendocrine L cells of the intestine in response to food. Exogenous GLP-1 administration at pharmacological doses results in many effects that are beneficial for treating type 2 diabetes, these include: (1) an increase in insulin secretion from ฮฒ cells; (2) a suppression of glucagon secretion from ฮฑ cells in the presence of hyperglycemia but not hypoglycemia; (3) a delay in gastric emptying and gut motility which in turns delays absorption of ingested nutrients and dampens post-prandial glucose excursion; and (4) an increase in the duration of postprandial satiety therefore suppressing appetite and decreasing food intake which eventually leads to weight loss. However, GLP-1 is subject to rapid enzymatic degradation, and therefore, not suitable for long-term treatment. A synthetic enzyme-resistant GLP-1 receptor agonist that reproduces the biological effects of GLP-1 is in use and more are under development. This review aims at providing a summary of the properties of GLP-1 and the development of GLP-1-based therapies for treatment of diabetes

    The prevention and treatment of venous thromboembolism with LMWHs and new anticoagulants

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    As the risk factors for thrombosis are becoming better understood, so is the need for anticoagulation. The inherent difficulties with warfarin are such that a low-molecular-weight heparin (LMWH) is often the key therapeutic. However, there are several different species of LMWH available to the practitioner, which leads to the need for an objective guide. New agents are coming onto the marketplace, and these may supersede both warfarin and the heparins. The current report will review the biochemistry and pharmacology of different LWMHs and identify which are more suitable for the different presentations of venous thromboembolism. It will conclude with a brief synopsis of new agents which may supersede warfarin and heparin

    Genome-wide detection of segmental duplications and potential assembly errors in the human genome sequence

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    BACKGROUND: Previous studies have suggested that recent segmental duplications, which are often involved in chromosome rearrangements underlying genomic disease, account for some 5% of the human genome. We have developed rapid computational heuristics based on BLAST analysis to detect segmental duplications, as well as regions containing potential sequence misassignments in the human genome assemblies. RESULTS: Our analysis of the June 2002 public human genome assembly revealed that 107.4 of 3,043.1 megabases (Mb) (3.53%) of sequence contained segmental duplications, each with size equal or more than 5 kb and 90% identity. We have also detected that 38.9 Mb (1.28%) of sequence within this assembly is likely to be involved in sequence misassignment errors. Furthermore, we have identified a significant subset (199,965 of 2,327,473 or 8.6%) of single-nucleotide polymorphisms (SNPs) in the public databases that are not true SNPs but are potential paralogous sequence variants. CONCLUSION: Using two distinct computational approaches, we have identified most of the sequences in the human genome that have undergone recent segmental duplications. Near-identical segmental duplications present a major challenge to the completion of the human genome sequence. Potential sequence misassignments detected in this study would require additional efforts to resolve

    Linking Value Chain Costs To Products And Customers: Survey And Evaluation Of Large U.S. Manufacturing Firmsโ€™ Current Practices

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    Success in a competitive environment requires effectively selecting an optimal mix of value chain activities. Despite the fact that corporate executives need to understand the costs and benefits of supporting particular products and customers, little empirical evidence is available on how, and how well, companies are linking their value chain costs to these two cost objects. The results of this study, based on responses to a survey of 120 large U.S. manufacturing companies, indicate that firms tend to link their value chain costs to products/product lines more than to customers/customer classes. For both cost objects, most of the cost allocation bases used is volume-based. These findings suggest that while there is attention to the value chain costs, there is room for increasing the proportion of costs traced to products and customers and for expanding the use of non-volume allocation bases

    Heavy metal concentrations in ceiling fan dusts sampled at schools around Serdang area, Selangor.

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    In this study, ceiling fan dust samples were collected from three schools in the district of Serdang Selangor, Malaysia. The sampled dust were analysed for the concentrations of Cd, Cu, Fe, Ni, Pb and Zn. The heavy metal ranges found in all the schools were 2.96-7.74 ฮผg/g dry weight for Cd, 75-442 ฮผg/g dry weight for Cu, 3445-3852 ฮผg/g dry weight for Fe, 24-66 ฮผg/g dry weight for Ni, 140-734 ฮผg/g dry weight for Pb and 439-880 ฮผg/g dry weight for Zn. SMK Seri Serdang School was found to have elevated concentrations of Cd, Cu, Ni, Pb, and Zn which indicated the anthropogenic sources of the study sites. In comparison to other reported studies in the literature, the maximum levels of Cd, Cu, Ni, and Pb were comparable or higher to those cities reported. Therefore, more monitoring studies should be conducted in future since dusts could be related to human health hazards and the dusts can be used as a potential monitoring tool for heavy metal pollution in the atmosphere
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