1,006 research outputs found

    CP Asymmetry in Charged Higgs Decays in MSSM

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    We discuss and compare the charge-parity (CP) asymmetry in the charged Higgs boson decays H -> \bar{u}_i d_j for the second and third generation quarks in the minimal supersymmetric standard model. As part of the analysis, we derive some general analytical formulas for the imaginary parts of two-point and three-point scalar one-loop integrals and use them for calculating vectorial and tensorial type integrals needed for the problem under consideration. We find that, even though each decay mode has a potential to yield a CP asymmetry larger than 10%, further analysis based on the number of required charged Higgs events at colliders favors the \bar{t}b, \bar{c}b, and \bar{c}s channels, whose asymmetry could reach 10-15% in certain parts of the parameter space.Comment: 25 pages, 9 figures. Discussion about charged Higgs observability added, typos corrected, accepted for publication in PR

    Vertical distribution and source identification of polycyclic aromatic hydrocarbons in anoxic sediment cores of Chini Lake, Malaysia: perylene as indicator of land plant-derived hydrocarbons.

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    Four anoxic sediment cores were collected from Chini Lake, Malaysia in order to investigate the variability of polycyclic aromatic hydrocarbon (PAH) and perylene concentrations. The study also determined significant differences of perylene concentrations in different sediment layers. Total PAH concentrations ranged from 248 to 8098 ng g−1 in the samples. Diagnostic PAH ratios such as methylphenanthrenes/phenanthrene (MP/P), phenanthrene/anthracene (P/A) and fluoranthene/(fluoranthene + pyrene) (Fl/(Fl + Py) revealed a dominance of pyrogenic influences and partial petrogenic inputs to the top sediment layers. Perylene concentrations were high in the top layers (12 cm). The average perylene concentrations accounted for 26–50% (0–12 cm) and 50–77% (12–36 cm) of pentacyclic-aromatic hydrocarbon isomers (PAI) present whereas it made up 10–34% (0–12 cm) and 46–66% (12–36 cm) of the total PAH. The average pyrene concentrations decreased with increasing depth and accounted for 62% (0–3 cm), 20–23% (3–12 cm) and 3–1.4% (12–36 cm) of perylene present. The results of hierarchical cluster analysis based on these ratios suggested different input sources for the top and bottom layers. It is concluded that the activity of termites on woody plants produced perylene which is supplied to the lake by run-off from the heavy and frequent rains in this Asian tropical climate. In addition, there was also in situ formation of perylene in the bottom layers due to diagenetic processes

    Polycyclic aromatic hydrocarbons and n-alkanes in suspended particulate matter and sediments from the Langat River, peninsular Malaysia

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    The Langat River basin has seen rapid developments in industrialization, urbanization and dramatic population increases during the past two decades. The composition and sources of polycyclic aromatic hydrocarbons (PAHs) and aliphatic hydrocarbon (n-alkanes) concentrations were determined in surface sediments (SS) and suspended particulate matter (SPM) collected from six locations in the Langat River. The total n-alkanes concentrations (6HC) ranged from 5900 to 23000 Pg/g in SPM and 1700 to 8600 Pg/g in SS samples. Total PAHs concentrations varied from 306 to 7968 ng/g in SPM and 558 to 980 ng/g in SS. PAHs and n-alkanes were dominated by higher molecular weight compounds in SS and low-medium molecular weight compounds in SPM. Carbon preference index (CPI) values for n- alkanes in ranges C25-33, C15-35 and C25-35 varied from 0.95 to 2.49 in SS and close to unity in SPM. The CPIs values indicated multiple n-alkanes sources (petrogenic and natural). PAHs isomer pairs ratios indicated multiple (petrogenic and pyrogenic) with predominance of pyrogenic PAH sources. Analysis of the possible source of PAHs and n- alkanes indicated a complicated, combined PAHs and n-alkanes source in the Langat River

    Distribution of PAHs and n-alkanes in Klang River surface sediments, Malaysia

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    Surface sediment samples were collected from five locations at the downstream of Klang River in January 2007 to examine the spatial distribution, composition, and sources of 19 parent polycyclic aromatic hydrocarbons (PAHs) and aliphatic hydrocarbon (n-alkanes) using gas chromatography-mass spectrometry. The total concentrations of the 19 PAHs in the sediments were found to range from 1304 to 2187 ng g-1 sediment. Meanwhile, total concentrations of n-alkanes ranged from 17008 to 27116 μg g-1 sediment. The concentration of n-alkanes in the sediment was significantly correlated (r = 0.991, p = 0.001) with the content of sediment organic carbon. In this study, all the sediments exhibited phenanthrene/anthracene (PHE/ANT >15) fluoranthene/(fluorantene+pyrene) (FLT/FLT+PYR 1), combustion PAHs/total PAHs (CombPAH/∑19PAH <0.3), terrigenous/aquatic ratio for hydrocarbons greater than 23. The also data showed that petrogenic and natural inputs were predominant at all the locations investigated. Multiple sources of n-alkanes and PAHs in the river sediments were also explained by low carbon preference index (CPI) values, different ratios of diploptene/∑C23-C25 n-alkanes, poor correlation between diploptene and ∑C23-C25, average chain length (ACL) of 29.54 ± 0.09, correlation between CPI and ACL (r = 0.847, p= 0.035), and high ratio of naphthalene/total PAHs

    Characterization of perylene in tropical environment : comparison of new and old fungus comb for identifying perylene precursor in Macrotermes gilvus termite nests of Peninsular Malaysia.

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    This is the first record on the distribution of perylene in new and old fungus combs of termite nest (Macrotermes gilvus) in order to determine perylene source in tropical environment. Twenty four samples of new and old fungus combs, inner and outer nest walls, fresh and decomposed bark, decomposed stem, soil, and soil-wood interface were collected in order to test of two hypotheses; i) Perylene is produced in the termite’s hindgut (M. gilvus) and ii) Perylene is present only in new fungus comb of M. gilvus termite nests. For one Station (Station A) the profile of perylene concentration was the following order: fungus comb > outer nest wall ≥ Soil-Wood interface ≥ decomposed stem ≥ decomposed bark ≥ Inner nest wall > Soil. For the other Station (i.e. B) the profile was new fungus comb > inner nest wall > old fungus comb ≥ outer nest wall ~ Soil. The perylene concentration was found up to 21-54 times higher in fungus comb as compare to the rest of the samples in Station A. whereas, the perylene concentration was 85-400 times higher in new fungus comb as compare to the remaining samples in Station B, this can be due to the production or accumulation of perylene in these nests. On the other hand, smaller termite nests (Stations C and E) no perylene was detected, due to the fact that the new fungus comb was not found in those nests. The results confirmed the following hypotheses; perylene occurs only in new fungus comb and may be attributed to the high concentrations of aromatic rings of lignin in new fungus comb

    Public sector procurement: the effectiveness of monitoring mechanism / Aida Maria Ismail … [et al.]

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    Issues in public sector procurement have been increasing lately. These issues are related to non-compliance or frauds that have been highlighted each year by the Auditor General. However, there seems to be no effective solutions in overcoming these issues. Therefore, this study attempted to examine the relationship between monitoring mechanisms and procurement issues in the public sector. The monitoring mechanisms that were of focus are the effectiveness of procurement procedures and the role of internal auditors towards issues in public procurement. The finding is that no job rotation in high-risk areas is the top factor that influences public procurement issues. Normally, the absence of job rotations will create opportunities for procurement officers to collude with outsiders to commit fraud. Besides job rotations, the other factors that influence procurement issues are related to components of control activities in the COSO framework. The major finding of the study has shown that both procurement procedures and the role of internal auditors have a negative relationship towards procurement issues in the public sector. However, only procurement procedures have a significant relationship towards procurement issues in the public sector compared to the role of internal auditors. In conclusion, both the monitoring mechanism used in this study in terms of procurement procedures and role of internal auditors affect procurement issues in the public sector

    Agrin mediates chondrocyte homeostasis and requires both LRP4 and alpha-dystroglycan to enhance cartilage formation in vitro and in vivo

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    Objectives Osteoarthritis (OA) is a leading cause of disability for which there is no cure. The identification of molecules supporting cartilage homeostasis and regeneration is therefore a major pursuit in musculoskeletal medicine. Agrin is a heparan sulfate proteoglycan which, through binding to low-density lipoprotein receptor-related protein 4 (LRP4), is required for neuromuscular synapse formation. In other tissues, it connects the cytoskeleton to the basement membrane through binding to α-dystroglycan. Prompted by an unexpected expression pattern, we investigated the role and receptor usage of agrin in cartilage. Methods Agrin expression pattern was investigated in human osteoarthritic cartilage and following destabilisation of the medial meniscus in mice. Extracellular matrix (ECM) formation and chondrocyte differentiation was studied in gain and loss of function experiments in vitro in three-dimensional cultures and gain of function in vivo, using an ectopic cartilage formation assay in nude mice. Receptor usage was investigated by disrupting LRP4 and α-dystroglycan by siRNA and blocking antibodies respectively. Results Agrin was detected in normal cartilage but was progressively lost in OA. In vitro, agrin knockdown resulted in reduced glycosaminoglycan content, downregulation of the cartilage transcription factor SOX9 and other cartilage-specific ECM molecules. Conversely, exogenous agrin supported cartilage differentiation in vitro and ectopic cartilage formation in vivo. In the context of cartilage differentiation, agrin used an unusual receptor repertoire requiring both LRP4 and α-dystroglycan. Conclusions We have discovered that agrin strongly promotes chondrocyte differentiation and cartilage formation in vivo. Our results identify agrin as a novel potent anabolic growth factor with strong therapeutic potential in cartilage regeneration

    5,5,7,12,14,14-Hexamethyl-1,8-diaza-4,11-diazo­niacyclo­tetra­deca-4,11-diene dichloride trihydrate

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    In the title compound, C16H34N4 2+·2Cl−·3H2O, the two protonated N atoms in the macrocyclic ring of the dication are located at diagonally opposite positions. There are two intramolecular N—H⋯N hydrogen bonds in the cation. The crystal structure features O—H⋯Cl, O—H⋯O, C—H⋯Cl and N—H⋯Cl hydrogen bonds

    Metastatic collecting duct carcinoma of the kidney treated with sunitinib

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    Collecting duct carcinoma (CDC) of the kidney is a rare and aggressive malignant tumor arising from the distal collecting tubules which has been shown to have a poor response to several kinds of systemic therapy. We present a case of metastatic CDC that responded favorably to a multiple tyrosine kinase inhibitor, sunitinib, achieving a partial response in both lung and skeletal metastases. To our knowledge, this is the first report showing therapeutic activity of sunitinib against CDC. Considering these findings, it would be worthwhile prospectively investigating the role of multiple tyrosine kinase inhibitors, particularly sunitinib, in the management of metastatic CDC
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