An unfitted Nitsche method for incompressible fluid-structure interaction using overlapping meshes

We consider the extension of the Nitsche method to the case of fluid–structure interaction problems on unfitted meshes. We give a stability analysis for the space semi-discretized problem and show how this estimate may be used to derive optimal error estimates for smooth solutions,irrespectively of the mesh/interface intersection. We also discuss different strategies for the time discretization, using either fully implicit or explicit coupling (loosely coupled) schemes. Some numerical examples illustrate the theoretical discussion

DOES DESIGN-BUILD (DB) OUTPERFORM CONSTRUCTION MANAGEMENT AT RISK (CMAR)? A COST AND SCHEDULE COMPARATIVE STUDY OF DB PROJECTS AND CMAR PROJECTS

Design-Build (DB) and Construction Management at Risk (CMAR) are two widely used alternative project delivery systems in the construction industry. Previous studies have found inconclusive results on which of the two has better cost and schedule performances when applied in construction projects. This study chose unit cost, change order factor, cost growth, schedule growth, and construction intensity as the metrics to measure the cost and schedule performance of both DB projects and CMAR projects. Two statistical analysis tools, Analysis of Variance and Wilcoxon Signed Rank Test, were applied to see if there is any difference between the two project delivery systems’ means of the five measurements. The test results were used to determine which project delivery system has better performance in the real world. The results showed that Design-Build is superior to Construction Management at Risk in construction intensity, while Construction Management at Risk has better performance on the change order, cost growth, and schedule growth. And there is no difference in unit cost

Evidence and modeling of turbulence bifurcation in L-mode confinement transitions on Alcator C-Mod

© 2020 Author(s). Analysis and modeling of rotation reversal hysteresis experiments show that a single turbulent bifurcation is responsible for the Linear to Saturated Ohmic Confinement (LOC/SOC) transition and concomitant intrinsic rotation reversal on Alcator C-Mod. Plasmas on either side of the reversal exhibit different toroidal rotation profiles and therefore different turbulence characteristics despite the profiles of density and temperature, which are indistinguishable within measurement uncertainty. Elements of this bifurcation are also shown to persist for auxiliary heated L-modes. The deactivation of subdominant (in the linear growth rate and contribution to heat transport) ion temperature gradient and trapped electron mode instabilities is identified as the only possible change in turbulence within a reduced quasilinear transport model across the reversal, which is consistent with the measured profiles and inferred heat and particle fluxes. Experimental constraints on a possible change from strong to weak turbulence, outside the description of the quasilinear model, are also discussed. These results indicate an explanation for the LOC/SOC transition that provides a mechanism for the hysteresis through the dynamics of subdominant modes and changes in their relative populations and does not involve a change in the most linearly unstable ion-scale drift-wave instability

Scientific Investigation of the Calf Raise Test Using the Calf Raise Mobile Application to Inform Test Administration and Interpretation

The Calf Raise Test (CRT) is a widely used functional assessment of triceps surae muscle-tendon unit function. While it exhibits acceptable reliability, administration inconsistencies and test parameter variations likely contribute to observed normative value discrepancies in the literature. Additionally, devices employed in research for standardisation and quantification of outcomes beyond the number of repetitions are often inaccessible in clinics. This Thesis addresses these gaps by conducting an evidence-based assessment of the CRT and examining how changes in test parameters affect outcomes. The overarching aims of this Thesis were to: (1) develop a valid and reliable method to assess the CRT in clinical practice that provides research-grade outcomes, and (2) examine the influence of changing CRT parameters on outcomes and triceps surae muscle function. To achieve these overarching aims, two literature reviews and three experimental studies were conducted. The first literature review, aligned with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, provides an overview of CRT devices used in research. Thirty-five studies were included, identifying seven CRT devices. The linear encoder emerged as the most used, quantifying all three main CRT outcomes (repetitions, peak height, and total work). However, its limited clinical use is attributed to hardware costs and need for programming skills. Chapter 3 introduces the Calf Raise application (CRapp), a smartphone application designed to aid standardise CRT procedures and automate outcomes. Thirteen individuals underwent single-leg CRT on both legs across three occasions. CRapp outcomes (i.e., repetitions, total work, total height, peak height, fatigue index, and peak power) were validated against 3D motion capture and force plate data, demonstrating excellent concurrent validity and agreement levels. The CRapp proved valid, reliable, and suitable for both research and clinical practice. Chapter 4 explores the impact of varying ankle starting positions on CRT outcomes in 49 healthy individuals, accounting for gender, age, body mass index (BMI), and physical activity levels. Participants performed single-leg CRT in three randomised conditions on three occasions: flat (0°), incline (10° dorsiflexion), and step (full dorsiflexion). Analysis of CRapp data indicate significant effects of ankle starting position on all CRT outcomes, emphasising the importance of ankle start position for CRT administration and interpreting test outcomes. Chapter 5 investigates the effects of varying cadence on CRT outcomes in 36 healthy individuals, considering gender, age, BMI, and physical activity levels. Participants performed single-leg CRT in three randomised conditions on three occasions: 30, 60, and 120 beats per minute. Significant cadence effects were observed on CRapp outcomes, hence this study confirmed that cadence does matter when administering the CRT and interpreting its outcomes. Chapter 6, a systematic review following PRISMA guidelines, examines changes in standing CRT parameters on triceps surae surface electromyography (EMG) activity and fatigue measures. Seven studies were included, indicating increased activity in medial gastrocnemius increased with feet externally rotated, knees straight, and added load; lateral gastrocnemius with feet internally rotated, knees straight, and added load; and soleus with knees bent, whole-body vibration, and added load. These findings can inform evidence-based practices, though further training studies are recommended. Overall, this Thesis introduces the CRapp, an innovative, valid, and reliable method of quantifying key CRT outcomes. Also, this Thesis provides a better understanding of the influence of varying CRT parameters on outcomes. The evidence-base generated from this Thesis may be used to inform best practice use and interpretation of the CRT and guide future research

Concomitant Crystallization in Propylene/Ethylene Random Copolymer with Strong Flow at Elevated Temperatures

Flow-induced crystallization of α- and γ-phases was studied for a propylene/ethylene random copolymer with 3.4 mol % ethylene at two high temperatures of 132 and 142 °C by combining a pressure-driven slit flow device with real-time synchrotron wide-angle X-ray diffraction. At 132 °C, it was found that both α- and γ-phases were generated at shear stresses ranging from 0.091 to 0.110 MPa and that the γ-phase always appeared later than the α-phase. However, for 142 °C and the same stresses, only the α-phase formed. Only upon cooling the partially crystallized copolymer did the γ-phase emerge. The lack of γ-crystals obtained at 142 °C is opposite to the behavior reported for quiescent crystallization under pressure, for which increasing temperature results in more and even pure γ-crystals. In the current study, the absence of γ-phase at 142 °C is tentatively associated with lack of epitaxial nucleation on α-lamellae and to relatively low growth rate of γ-crystals

A timely computer-aided detection system for acute ischemic and hemorrhagic stroke on CT in an emergency environment

Standalone Presentations: no. LL-IN1105BACKGROUND: When a patient is accepted in the emergency room suspected of stroke, time is of the most importance. The infarct brain area suffers irreparable damage as soon as three hours after the onset of stroke symptoms. Non-contrast CT scan is the standard first line of investigation used to identify hemorrhagic stroke cases. However, CT brain images do not show hyperacute ischemia and small hemorrhage clearly and thus may be missed by emergency physicians. We reported a timely computer-aided detection (CAD) system for small hemorrhages on CT that has been successfully developed as an aid to ER physicians to help improve detection for Acute Intracranial Hemorrhage (AIH). This CAD system has been enhanced for diagnosis of acute ischemic stroke in addition to hemorrhagic stroke, which becomes a more complete and clinically useful tool for assisting emergency physicians and radiologists. In the detection algorithm, brain matter is first segmented, realigned, and left-right brain symmetry is evaluated. As in the AIH system, the system confirms hemorrhagic stroke by detecting blood presence with anatomical and medical knowledge-based criteria. For detecting ischemia, signs such as regional hypodensity, blurring of grey and white matter differentiation, effacement of cerebral sulci, and hyperdensity in middle cerebral artery, are evaluated …published_or_final_versio

Colección ictiológica del Museo de La Plata: la Familia Trichomycteridae

En este número de la Serie Técnica y Didáctica de ProBiota se comienza a difundir los materiales que se encuentran depositados en la Colección Ictiológica del Museo de La Plata, cuyos antecedentes se pueden ver en Miquelarena y Nadalin 2014. En este caso tratamos a la Familia Trichomycteridae la cual está muy bien representada en nuestro país. Como dato histórico podemos mencionar que entre los colectores de los materiales señalados en el texto, se encuentran figuras de las Ciencias Naturales de la Argentina, comenzando con el fundador del propio Museo, Francisco P. Moreno, así como otros directores: Joaquín Frenguelli y Emiliano Mac Donagh. Además de otros científicos de renombre como Carlos Spegazzini, Ángel Cabrera, Raúl A. Ringuelet, Alberto Rex González y Argentino A. Bonetto. En el material mencionado se contabilizan cuatro especies tipo y otras provenientes de Brasil producto de un reciente intercambio con el Museo Nacional de Río Janeiro (MNRJ).Fil: Fernandez, Luis Alfredo. Fundación Miguel Lillo; Argentina. Universidad Nacional de Catamarca. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Nadalin, Diego O.. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología de Vertebrados; ArgentinaFil: López, Hugo L.. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología de Vertebrados; ArgentinaFil: Serio, Ma. Josefina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología de Vertebrados; Argentin

Elevation and cholera: an epidemiological spatial analysis of the cholera epidemic in Harare, Zimbabwe, 2008-2009

BACKGROUND: In highly populated African urban areas where access to clean water is a challenge, water source contamination is one of the most cited risk factors in a cholera epidemic. During the rainy season, where there is either no sewage disposal or working sewer system, runoff of rains follows the slopes and gets into the lower parts of towns where shallow wells could easily become contaminated by excretes. In cholera endemic areas, spatial information about topographical elevation could help to guide preventive interventions. This study aims to analyze the association between topographic elevation and the distribution of cholera cases in Harare during the cholera epidemic in 2008 and 2009. METHODS: We developed an ecological study using secondary data. First, we described attack rates by suburb and then calculated rate ratios using whole Harare as reference. We illustrated the average elevation and cholera cases by suburbs using geographical information. Finally, we estimated a generalized linear mixed model (under the assumption of a Poisson distribution) with an Empirical Bayesian approach to model the relation between the risk of cholera and the elevation in meters in Harare. We used a random intercept to allow for spatial correlation of neighboring suburbs. RESULTS: This study identifies a spatial pattern of the distribution of cholera cases in the Harare epidemic, characterized by a lower cholera risk in the highest elevation suburbs of Harare. The generalized linear mixed model showed that for each 100 meters of increase in the topographical elevation, the cholera risk was 30% lower with a rate ratio of 0.70 (95% confidence interval=0.66-0.76). Sensitivity analysis confirmed the risk reduction with an overall estimate of the rate ratio between 20% and 40%. CONCLUSION: This study highlights the importance of considering topographical elevation as a geographical and environmental risk factor in order to plan cholera preventive activities linked with water and sanitation in endemic areas. Furthermore, elevation information, among other risk factors, could help to spatially orientate cholera control interventions during an epidemic

Stereoselective and catalytic synthesis of anti-β-Alkoxy-α-azido carboxylic derivatives

Direct addition of a chiral N-azidoacetyl thiazolidinethione to a variety of dialkyl acetals catalyzed by a commercially available and structurally simple nickel(II) complex gives access in good yields and a highly stereocontrolled manner to anti-beta-alkoxy-alpha-azido carboxylic derivatives which, in turn, can be easily converted into a wide array of enantiomerically pure compounds