73 research outputs found

    Anomalous Higgs couplings in egamma collision with initial beam and final state polarizations

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    We investigate the constraints on the anomalous WWH couplings through the process eγνeWHe^{-}\gamma \to \nu_{e} W^{-} H. Considering incoming beam polarizations and the longitudinal and transverse polarization states of the final W boson, we find 95% confidence level limits on the anomalous coupling parameters with an integrated luminosity of 500 fb1fb^{-1} and s\sqrt{s}= 0.5 and 1 TeV energy. We show that initial beam and final state polarizations highly improve the sensitivity limits of the anomalous coupling parameters bWb_{W} and βW\beta_{W}.Comment: 15 pages, 10 figures, 2 table

    Chirality blockade of Andreev reflection in a magnetic Weyl semimetal

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    A Weyl semimetal with broken time-reversal symmetry has a minimum of two species of Weyl fermions, distinguished by their opposite chirality, in a pair of Weyl cones at opposite momenta ±K\pm K that are displaced in the direction of the magnetization. Andreev reflection at the interface between a Weyl semimetal in the normal state (N) and a superconductor (S) that pairs ±K\pm K must involve a switch of chirality, otherwise it is blocked. We show that this "chirality blockade" suppresses the superconducting proximity effect when the magnetization lies in the plane of the NS interface. A Zeeman field at the interface can provide the necessary chirality switch and activate Andreev reflection.Comment: 15 pages, 9 figures. V2: added investigation of the dependence of the chirality blockade on the direction of the magnetization and (Appendix C) calculations of the Fermi-arc mediated Josephson effec

    Efecto del carvacrol en la estabilidad oxidativa del aceite de palma durante la fritura

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    Fats and oils deteriorate physically and chemically at frying temperatures due to several reasons. The objective of this study was to assess the effect of carvacrol on the oxidative stability of palm oil during a repeated frying process. Potatoes were serially fried in carvacrol-added palm oil, BHT-added palm oil and a control oil (without any antioxidants). After each tenth frying cycle, several chemical analyses were carried out on collected samples to evaluate deterioration in the oils. The free fatty acid, para-anisidine, iodine, and total polar component values of the fresh oil were 0.080, 2.85, 57.1 and 7.5, respectively. These values changed to 0.165, 11.80, 46.7, 11.0, respectively for the control oil; 0.151, 11.28, 49.2 and 10.5 for BHT-added oil; 0.140, 7.19, 51.7, 10.0 for carvacrol-added oil after 40 frying cycles. The results revealed that the use of carvacrol could significantly improve the oxidative stability of palm oil when compared to the control samples. This effect was also comparable to BHT. Using carvacrol in frying oil slowed down the rate of the formation of conjugated dienes and trienes compared to the oil with BHT and the control. The frying process significantly changed the viscosity of the oil samples.Las grasas y aceites se deterioran física y químicamente a las temperaturas de fritura debido a diferentes razones. El objetivo de este estudio fue evaluar el efecto del carvacrol en la estabilidad oxidativa del aceite de palma durante el proceso de fritura repetida. Se sometió a fritura repetida patatas en el aceite de palma con carvacrol agregado, en aceite de palma con BHT agregado y en aceite control (sin antioxidante). Después de cada décimo ciclo de fritura, se realizaron diferentes análisis sobre las muestras recogidas para evaluar el deterioro de los aceites. Ácidos grasos libre, para-anisidina, índice de yodo y componentes polares totales del aceite fresco fueron: 0,080, 2,85, 57,1 y 7,5, respectivamente. Estos valores cambian a 0.165, 11.80, 46.7 y 11.0, respectivamente, para el aceite de control; 0.151, 11.28, 49.2 y 10.5 para el aceite con BHT añadido; 0.140, 7.19, 51.7 y 10.0 para el aceite con carvacrol añadido después de 40 frituras. Los resultados revelaron que el uso de carvacrol puede mejorar significativamente la estabilidad oxidativa del aceite de palma en comparación con las muestras control. Este efecto también era comparable a la del BHT. El uso de carvacrol en el aceite de fritura ralentizó la velocidad de formación de dienos y trienos conjugados en comparación con el aceite con BHT y el de control. Los procesos de fritura producen grandes cambios en la viscosidad de las muestras de aceite

    Intrinsic Spin Hall Edges

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    The prediction of intrinsic spin Hall currents by Murakami \textit{et al.} and Sinova \textit{et al.} raised many questions about methods of detection and the effect of disorder. We focus on a contact between a Rashba type spin orbit coupled region with a normal two-dimensional electron gas and show that the spin Hall currents, though vanishing in the bulk of the sample, can be recovered from the edges. We also show that the current induced spin accumulation in the spin orbit coupled system diffuses into the normal region and contributes to the spin current in the leads.Comment: To appear in Physical Review Letters. 5 pages, 2 figures, RevTe

    Thrombotic risk assessment in antiphospholipid syndrome: do noncriteria antibodies contribute?

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    BACKGROUND/AIM: In this cross-sectional study, it was aimed to test the predictive value of noncriteria antiphospholipid antibodies (aPL) in addition to the global antiphospholipid syndrome score (GAPSS) in predicting vascular thrombosis (VT) in a cohort of patients with APS and aPL (+) systemic lupus erythematosus (SLE). MATERIAL AND METHODS: This study included 50 patients with primary APS, 68 with SLE/APS, and 52 with aPL (+) SLE who were classified according to VT as VT ± pregnancy morbidity (PM), PM only or aPL (+) SLE. Antiphospholipid serology consisting of lupus anticoagulant (LA), anticardiolipin (aCL) immunoglobulin G (IgG)/IgM/IgA, antibeta2 glycoprotein I (aβ2GPI) IgG/IgM/IgA, antiphosphatidylserine/prothrombin (aPS/PT) IgG/IgM and antidomain-I (aDI) IgG was determined for each patient. The GAPSS and adjusted GAPSS (aGAPSS) were calculated for each patient, as previously defined. Logistic regression analysis was carried out with thrombosis as the dependent variable and high GAPSS, aCL IgA, aβ2GPI IgA, and aDI IgG as independent variables. RESULTS: The mean GAPSS and aGAPSS of the study population were 11.6 ± 4.4 and 9.6 ± 3.8. Both the VT ± PM APS (n = 105) and PM only APS (n = 13) groups had significantly higher GAPSS and aGAPSS values compared to the aPL (+) SLE (n = 52) group. The patients with recurrent thrombosis had higher aGAPSS but not GAPSS than those with a single thrombotic event. The computed area under the receiver operating characteristic curve demonstrated that a GAPSS ≥13 and aGAPSS ≥10 had the best predictive values for thrombosis. Logistic regression analysis including a GAPSS ≥13, aCL IgA, aβ2GPI IgA, and aDI IgG showed that none of the factors other than a GAPSS ≥13 could predict thrombosis. CONCLUSION: Both the GAPSS and aGAPSS successfully predict the thrombotic risk in aPL (+) patients and aCL IgA, aβ2GPI IgA, and aDI IgG do not contribute to high a GAPSS or aGAPSS

    Anomalous quartic WWgammagamma and WWZgamma couplings through WWZ production in gamma gamma colliders

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    We find 95% confidence level limits on the anomalous coupling parameters a0a_0, aca_c and ana_n with an integrated luminosity of 500fb1500fb^{-1} and s=0.5,1\sqrt s =0.5, 1 and 1.5 TeV energies. We take into account incoming beam polarizations and also the final state polarizations of the gauge bosons in the cross-section calculations to improve the bounds. We show that polarization leads to a significant amount of improvement in the sensitivity limits.Comment: 16 pages, 6 figures, 3 table

    Spin Accumulation in Diffusive Conductors with Rashba and Dresselhaus Spin-Orbit Interaction

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    We calculate the electrically induced spin accumulation in diffusive systems due to both Rashba (with strength α)\alpha) and Dresselhaus (with strength β)\beta) spin-orbit interaction. Using a diffusion equation approach we find that magnetoelectric effects disappear and that there is thus no spin accumulation when both interactions have the same strength, α=±β\alpha=\pm \beta. In thermodynamically large systems, the finite spin accumulation predicted by Chaplik, Entin and Magarill, [Physica E {\bf 13}, 744 (2002)] and by Trushin and Schliemann [Phys. Rev. B {\bf 75}, 155323 (2007)] is recovered an infinitesimally small distance away from the singular point α=±β\alpha=\pm \beta. We show however that the singularity is broadened and that the suppression of spin accumulation becomes physically relevant (i) in finite-sized systems of size LL, (ii) in the presence of a cubic Dresselhaus interaction of strength γ\gamma, or (iii) for finite frequency measurements. We obtain the parametric range over which the magnetoelectric effect is suppressed in these three instances as (i) αβ1/mL|\alpha|-|\beta| \lesssim 1/mL, (ii)αβγpF2|\alpha|-|\beta| \lesssim \gamma p_{\rm F}^2, and (iii) |\alpha|-|\beta| \lesssiM \sqrt{\omega/m p_{\rm F}\ell} with \ell the elastic mean free path and pFp_{\rm F} the Fermi momentum. We attribute the absence of spin accumulation close to α=±β\alpha=\pm \beta to the underlying U (1) symmetry. We illustrate and confirm our predictions numerically

    Coagulation factor V gene mutation increases the risk of venous thrombosis in Behcet's disease

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    We investigated the prevalence of the coagulation factor V gene G1691A mutation in 64 patients with Behcet's disease (BD) and in 107 apparently healthy individuals. The mutation was present in the heterozygous state in 37.5% of the patients with a history of deep vein thrombosis (12/32) and in 9.4% of the patients without any thrombotic event (3/32). Eleven healthy individuals were also heterozygous for the mutation (10.3%). The prevalence of the mutation in BD patients with and without thrombosis was significantly different (P = 0.0079). We conclude that the factor V gene mutation may play a major role in the development of venous thrombosis in BD

    Lower vitamin D is associated with metabolic syndrome and insulin resistance in systemic lupus: data from an international inception cohort

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    OBJECTIVES: Vitamin D (25(OH)D) deficiency and metabolic syndrome (MetS) may both contribute to increased cardiovascular risk in systemic lupus erythematosus (SLE). We aimed to examine the association of demographic factors, SLE phenotype, therapy and vitamin D levels with MetS and insulin resistance. METHODS: The Systemic Lupus International Collaborating Clinics (SLICC) enrolled patients recently diagnosed with SLE (<15 months) from 33 centres across 11 countries from 2000. Clinical, laboratory and therapeutic data were collected. Vitamin D level was defined according to tertiles based on distribution across this cohort, which were set at T1 (10-36 nmol/l), T2 (37-60 nmol/l) and T3 (61-174 nmol/l). MetS was defined according to the 2009 consensus statement from the International Diabetes Federation. Insulin resistance was determined using the HOMA-IR model. Linear and logistic regressions were used to assess the association of variables with vitamin D levels. RESULTS: Of the 1847 patients, 1163 (63%) had vitamin D measured and 398 (34.2%) subjects were in the lowest 25(OH)D tertile. MetS was present in 286 of 860 (33%) patients whose status could be determined. Patients with lower 25(OH)D were more likely to have MetS and higher HOMA-IR. The MetS components, hypertension, hypertriglyceridemia and decreased HDL were all significantly associated with lower 25(OH)D. Increased average glucocorticoid exposure was associated with higher insulin resistance. CONCLUSIONS: MetS and insulin resistance are associated with lower vitamin D in patients with SLE. Further studies could determine whether vitamin D repletion confers better control of these cardiovascular risk factors and improve long-term outcomes in SLE
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