5,862 research outputs found

    Constrained spin dynamics description of random walks on hierarchical scale-free networks

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    We study a random walk problem on the hierarchical network which is a scale-free network grown deterministically. The random walk problem is mapped onto a dynamical Ising spin chain system in one dimension with a nonlocal spin update rule, which allows an analytic approach. We show analytically that the characteristic relaxation time scale grows algebraically with the total number of nodes NN as TNzT \sim N^z. From a scaling argument, we also show the power-law decay of the autocorrelation function C_{\bfsigma}(t)\sim t^{-\alpha}, which is the probability to find the Ising spins in the initial state {\bfsigma} after tt time steps, with the state-dependent non-universal exponent α\alpha. It turns out that the power-law scaling behavior has its origin in an quasi-ultrametric structure of the configuration space.Comment: 9 pages, 6 figure

    GALEX, Optical and IR Light Curves of MQ Dra: UV Excesses at Low Accretion Rates

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    Ultraviolet light curves constructed from NUV and FUV detectors on GALEX reveal large amplitude variations during the orbital period of the Low Accretion Rate Polar MQ Dra (SDSSJ1553+55). This unexpected variation from a UV source is similar to that seen and discussed in the Polar EF Eri during its low state of accretion, even though the accretion rate in MQ Dra is an order of magnitude lower than even the low state of EF Eri. The similarity in phasing of the UV and optical light curves in MQ Dra imply a similar location for the source of light. We explore the possibilities of hot spots and cyclotron emission with simple models fit to the UV, optical and IR light curves of MQ Dra. To match the GALEX light curves with a single temperature circular hot spot requires different sizes of spots for the NUV and FUV, while a cyclotron model that can produce the optical harmonics with a magnetic field near 60 MG requires multipoles with fields > 200 MG to match the UV fluxes.Comment: accepted for ApJ; 15 pages, 7 tables, 8 fig

    Statin use and association with colorectal cancer survival and risk:Case control study with prescription data linkage

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    Background: In Scotland colorectal cancer (CRC) is the third most common cancer and a leading cause of cancer death. Epidemiological studies have reported conflicting associations between statins and CRC risk and there is one published report of the association between statins and CRC survival.Methods: Analysis was carried out on 309 cases and 294 controls from the Scottish Study of Colorectal Cancer (SOCCS). Cox's hazard and logistic regression models were applied to investigate the association between statin use and CRC risk and survival.Results: In an adjusted logistic regression model, statins were found to show a statistically significant association for three of the four statin variables and were found to not show a statistically significant association with either all-cause or CRC-specific mortality (OR 0.49; 95%CI 0.49-1.36; p-value = 0.17 and OR 0.33; 95%CI 0.08-1.35; P-value = 0.12, respectively).Conclusion: We did find a statistically significant association between statin intake and CRC risk but not statin intake and CRC-specific mortality. However, the study was insufficiently powered and larger scale studies may be advisable.</p

    GALEX and Optical Light Curves of WX LMi, SDSSJ103100.5+202832.2 and SDSSJ121209.31+013627.7

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    {\it GALEX} near ultraviolet (NUV) and far-ultraviolet (FUV) light curves of three extremely low accretion rate polars show distinct modulations in their UV light curves. While these three systems have a range of magnetic fields from 13 to 70 MG, and of late type secondaries (including a likely brown dwarf in SDSSJ121209.31+013627.7), the accretion rates are similar, and the UV observations imply some mechanism is operating to create enhanced emission zones on the white dwarf. The UV variations match in phase to the two magnetic poles viewed in the optical in WX LMi and to the single poles evident in the optical in SDSSJ1212109.31+013627.7 and SDSSJ103100.55+202832.2. Simple spot models of the UV light curves show that if hot spots are responsible for the UV variations, the temperatures are on the order of 10,000-14,000K. For the single pole systems, the size of the FUV spot must be smaller than the NUV and in all cases, the geometry is likely more complicated than a simple circular spot.Comment: 29 pages, 4 tables, 10 figures, Astrophysical Journal, accepte

    Percutaneous transhepatic cholangiography and biliary drainage after liver transplantation: A five-year experience

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    Evaluation of the biliary tract by percutaneous transhepatic cholangiography (PTC) is often required in liver transplant patients with an abnormal postoperative course. Indications for PTC include failure of liver enzyme levels to return to normal postoperatively, an elevation of serum bilirubin or liver enzyme levels, suspected bile leak, biliary obstructive symptoms, cholangitis, and sepsis. Over a 5-year period 625 liver transplants in 477 patients were performed at the University Health Center of Pittsburgh. Fifty-three patients (56 transplants) underwent 70 PTCs. Complications diagnosed by PTC included biliary strictures, bile leaks, bilomas, liver abscesses, stones, and problems associated with internal biliary stents. Thirty-two percutaneous transhepatic biliary drainage procedures were performed. Ten transplantation patients underwent balloon dilatation of postoperative biliary strictures. Interventional radiologic techniques were important in treating other complications and avoiding additional surgery in many of these patients. © 1987 Springer-Verlag New York Inc

    Are we there yet?:An update on transitional care in rheumatology

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    Abstract Significant progress has been made in the understanding of transitional care in rheumatology over the last few decades, yet universal implementation has not been realised and unmet needs continue to be reported. Possible explanations for this include lack of evidence as to which model is most effective; lack of attention to the multiple dimensions, stakeholders and systems involved in health transitions; and lack of consideration of the developmental appropriateness of transition interventions and the services/organisations/systems where such interventions are delivered. Successful transition has major implications to both the young people with juvenile-onset rheumatic disease and their families. Future research in this area will need to reflect both the multidimensional (biopsychosocial) and the multisystemic (multiple systems and stakeholders across personal/social/family support networks and health/social care/education systems). Only then will we be able to determine which aspects of transition readiness and service components influence which dimension. It is therefore imperative we continue to research and develop this area, involving both paediatric and adult rheumatology clinicians and researchers, remembering to look beyond both the condition and our discipline. Neither should we forget to tap into the exciting potential associated with digital technology to ensure further advances in transitional care are brought about in and beyond rheumatology

    N-[(2-Chloro-3-quinol­yl)meth­yl]-4-fluoro­aniline

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    In the title compound, C16H12ClFN2, the dihedral angle between the quinoline ring system and the flourophenyl ring is 86.70 (4)°. In the crystal, mol­ecules are linked into chains along the a axis by N—H⋯N hydrogen bonds. In addition, C—H⋯π inter­actions involving the two benzene rings are observed

    Nonsystematic Reporting Biases of the SARS-CoV-2 Variant Mu Could Impact Our Understanding of the Epidemiological Dynamics of Emerging Variants

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    Developing a timely and effective response to emerging SARS-CoV-2 variants of concern (VOCs) is of paramount public health importance. Global health surveillance does not rely on genomic data alone to identify concerning variants when they emerge. Instead, methods that utilize genomic data to estimate the epidemiological dynamics of emerging lineages have the potential to serve as an early warning system. However, these methods assume that genomic data are uniformly reported across circulating lineages. In this study, we analyze differences in reporting delays among SARS-CoV-2 VOCs as a plausible explanation for the timing of the global response to the former VOC Mu. Mu likely emerged in South America in mid-2020, where its circulation was largely confined. In this study, we demonstrate that Mu was designated as a VOC ∼1 year after it emerged and find that the reporting of genomic data for Mu differed significantly than that of other VOCs within countries, states, and individual laboratories. Our findings suggest that nonsystematic biases in the reporting of genomic data may have delayed the global response to Mu. Until they are resolved, the surveillance gaps that affected the global response to Mu could impede the rapid and accurate assessment of future emerging variants
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