99 research outputs found

    The role of tank-treading motions in the transverse migration of a spheroidal vesicle in a shear flow

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    The behavior of a spheroidal vesicle, in a plane shear flow bounded from one side by a wall, is analysed when the distance from the wall is much larger than the spheroid radius. It is found that tank treading motions produce a transverse drift away from the wall, proportional to the spheroid eccentricity and the inverse square of the distance from the wall. This drift is independent of inertia, and is completely determined by the characteristics of the vesicle membrane. The relative strength of the contribution to drift from tank-treading motions and from the presence of inertial corrections, is discussed.Comment: 16 pages, 1 figure, Latex. To appear on J. Phys. A (Math. Gen.

    Perturbation theory for large Stokes number particles in random velocity fields

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    We derive a perturbative approach to study, in the large inertia limit, the dynamics of solid particles in a smooth, incompressible and finite-time correlated random velocity field. We carry on an expansion in powers of the inverse square root of the Stokes number, defined as the ratio of the relaxation time for the particle velocities and the correlation time of the velocity field. We describe in this limit the residual concentration fluctuations of the particle suspension, and determine the contribution to the collision statistics produced by clustering. For both concentration fluctuations and collision velocities, we analyze the differences with the compressible one-dimensional case.Comment: Latex, 12 pages, 2 eps figures include

    Exact Free Energy Functional for a Driven Diffusive Open Stationary Nonequilibrium System

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    We obtain the exact probability exp[LF({ρ(x)})]\exp[-L {\cal F}(\{\rho(x)\})] of finding a macroscopic density profile ρ(x)\rho(x) in the stationary nonequilibrium state of an open driven diffusive system, when the size of the system LL \to \infty. F\cal F, which plays the role of a nonequilibrium free energy, has a very different structure from that found in the purely diffusive case. As there, F\cal F is nonlocal, but the shocks and dynamic phase transitions of the driven system are reflected in non-convexity of F\cal F, in discontinuities in its second derivatives, and in non-Gaussian fluctuations in the steady state.Comment: LaTeX2e, RevTeX4, PiCTeX. Four pages, one PiCTeX figure included in TeX source fil

    Stability of scaling regimes in d2d\geq 2 developed turbulence with weak anisotropy

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    The fully developed turbulence with weak anisotropy is investigated by means of renormalization group approach (RG) and double expansion regularization for dimensions d2d\ge 2. Some modification of the standard minimal substraction scheme has been used to analyze stability of the Kolmogorov scaling regime which is governed by the renormalization group fixed point. This fixed point is unstable at d=2d=2; thus, the infinitesimally weak anisotropy destroyes above scaling regime in two-dimensional space. The restoration of the stability of this fixed point, under transition from d=2d=2 to d=3,d=3, has been demonstrated at borderline dimension 2<dc<3 2<d_c<3. The results are in qualitative agreement with ones obtained recently in the framework of the usual analytical regularization scheme.Comment: 23 pages, 2 figure

    Regularity Properties and Pathologies of Position-Space Renormalization-Group Transformations

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    We reconsider the conceptual foundations of the renormalization-group (RG) formalism, and prove some rigorous theorems on the regularity properties and possible pathologies of the RG map. Regarding regularity, we show that the RG map, defined on a suitable space of interactions (= formal Hamiltonians), is always single-valued and Lipschitz continuous on its domain of definition. This rules out a recently proposed scenario for the RG description of first-order phase transitions. On the pathological side, we make rigorous some arguments of Griffiths, Pearce and Israel, and prove in several cases that the renormalized measure is not a Gibbs measure for any reasonable interaction. This means that the RG map is ill-defined, and that the conventional RG description of first-order phase transitions is not universally valid. For decimation or Kadanoff transformations applied to the Ising model in dimension d3d \ge 3, these pathologies occur in a full neighborhood {β>β0,h<ϵ(β)}\{ \beta > \beta_0 ,\, |h| < \epsilon(\beta) \} of the low-temperature part of the first-order phase-transition surface. For block-averaging transformations applied to the Ising model in dimension d2d \ge 2, the pathologies occur at low temperatures for arbitrary magnetic-field strength. Pathologies may also occur in the critical region for Ising models in dimension d4d \ge 4. We discuss in detail the distinction between Gibbsian and non-Gibbsian measures, and give a rather complete catalogue of the known examples. Finally, we discuss the heuristic and numerical evidence on RG pathologies in the light of our rigorous theorems.Comment: 273 pages including 14 figures, Postscript, See also ftp.scri.fsu.edu:hep-lat/papers/9210/9210032.ps.

    Common Variants at 10 Genomic Loci Influence Hemoglobin A(1C) Levels via Glycemic and Nonglycemic Pathways

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    OBJECTIVE Glycated hemoglobin (HbA1c), used to monitor and diagnose diabetes, is influenced by average glycemia over a 2- to 3-month period. Genetic factors affecting expression, turnover, and abnormal glycation of hemoglobin could also be associated with increased levels of HbA1c. We aimed to identify such genetic factors and investigate the extent to which they influence diabetes classification based on HbA1c levels. RESEARCH DESIGN AND METHODS We studied associations with HbA1c in up to 46,368 nondiabetic adults of European descent from 23 genome-wide association studies (GWAS) and 8 cohorts with de novo genotyped single nucleotide polymorphisms (SNPs). We combined studies using inverse-variance meta-analysis and tested mediation by glycemia using conditional analyses. We estimated the global effect of HbA1c loci using a multilocus risk score, and used net reclassification to estimate genetic effects on diabetes screening. RESULTS Ten loci reached genome-wide significant association with HbA1c, including six new loci near FN3K (lead SNP/P value, rs1046896/P = 1.6 × 10−26), HFE (rs1800562/P = 2.6 × 10−20), TMPRSS6 (rs855791/P = 2.7 × 10−14), ANK1 (rs4737009/P = 6.1 × 10−12), SPTA1 (rs2779116/P = 2.8 × 10−9) and ATP11A/TUBGCP3 (rs7998202/P = 5.2 × 10−9), and four known HbA1c loci: HK1 (rs16926246/P = 3.1 × 10−54), MTNR1B (rs1387153/P = 4.0 × 10−11), GCK (rs1799884/P = 1.5 × 10−20) and G6PC2/ABCB11 (rs552976/P = 8.2 × 10−18). We show that associations with HbA1c are partly a function of hyperglycemia associated with 3 of the 10 loci (GCK, G6PC2 and MTNR1B). The seven nonglycemic loci accounted for a 0.19 (% HbA1c) difference between the extreme 10% tails of the risk score, and would reclassify ∼2% of a general white population screened for diabetes with HbA1c. CONCLUSIONS GWAS identified 10 genetic loci reproducibly associated with HbA1c. Six are novel and seven map to loci where rarer variants cause hereditary anemias and iron storage disorders. Common variants at these loci likely influence HbA1c levels via erythrocyte biology, and confer a small but detectable reclassification of diabetes diagnosis by HbA1c

    Using radio telemetry to evaluate post‐stocking survival and behavior of large fingerling Walleye in three Iowa, USA lakes

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    Stocking Walleye Sander vitreus is a common management tool to augment populations where natural reproduction is limited. Some hatcheries have progressively raised larger fingerling Walleye to improve post-stocking survival; however, little is known about large fingerling Walleye poststocking survival and behavior. Our objectives were to evaluate large fingerling Walleye (\u3e200 mm TL) post-stocking daily apparent survival, depth use, dispersal, and home range size in three Iowa, USA lakes. Walleye (209-265 mm, n=15 per lake, 45 fish total) were implanted with radio tags, stocked 26-30 October 2017, and tracked until 30 May 2018. Cormack-Jolly-Seber recapture models estimated Walleye apparent survival increased with days post-stocking and Walleye length, resulting in 76% (95% CI: 44-89%) cumulative survival by May. Walleye in Brushy Creek were located in deeper water (mean = 5.1 m, SE = 0.2) than Big Creek (mean = 3.3 m, SE = 0.2) or East Okoboji (mean = 1.7 m, SE = 0.1) but depth use did not vary with days post-stocking. Walleye dispersed an average of 1,355 m (SE = 234) within 13 d across all lakes with home range size larger in Big Creek (67.9 ha, SE = 21.7) than Brushy Creek (15.5 ha, SE = 15.7) and East Okoboji (31.0 ha, SE = 14.0). Our results indicate Walleye post-stocking survival is high overall with most mortality occurring within 20 d as Walleye are dispersing, suggesting managers should focus on improving survival during this critical period to improve stocking success

    Rancang Bangun Peak Flow Meter dengan Output Suara dan Pemantauan Android

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    Peak Flow Meter (PFM) is a tool to measure the amount of air flow in the airway (PFR) and to detect asthma. The output value of PFR can be influenced by several factors, such as age, respiratory muscle strength, height and gender. In this research, airway measurements are used to measure the condition of patients suffering from asthma. The author aims to make this tool so that it can find out how to design and make a peak flow meter output sound tool, measure the peak current and can know how the MPXV7002DP sensor works in regulating output in the form of sound. The method used by the author is to design or make a tool peak flow meter output sound. This MPXV7002DP sensor works when the sensor receives air blows from the flow sensor which automatically reads the highest air pressure from the breath. The test results using the VT Mobile Medical Gas Flow Analyzer prove that the largest percentage error is 2.4%, with the blowing rate on the Peak Flow Meter is 64.0 lpm and the blowing rate on VT mobile is 62.50 lpm. Therefore, this tool can be said to be very certain to detect asthma. Then it can be concluded that the peak flow meter is feasible and meets the specified requirements
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