Direct numerical simulations of membrane wings at low reynolds number

Direct numerical simulations (DNS) of membrane wings at low Reynolds numbers were performed at different angles of attack using a new high-fidelity fluid-structure interaction computational framework. A newly implemented boundary data immersion method coupled to a membrane structural solver was used in a well validated DNS code. DNS performed at lower Reynolds number Re=2500 agree well with reference data, validating the new numerical set-up. For higher Reynolds number Re=10,000, where the membrane becomes unsteady and the flow motion becomes more chaotic, it is found that spectra of membrane deflection and pressure coefficient are still closely correlated. The computational set-up is employed for preliminary studies of the stability characteristics of separation bubbles with vortex shedding for membrane aerofoils. The evolution of initial perturbations introduced on the flow field were investigated recording the temporal growth of the spanwise Fourier modes of the perturbations. Regions of amplification of perturbations were identified for the case at higher Reynolds number and angle of attack

Does tailoring instructional style to a medical student\u27s self-perceived learning style improve performance when teaching intravenous catheter placement? A randomized controlled study.

BACKGROUND: Students may have different learning styles. It is unclear, however, whether tailoring instructional methods for a student\u27s preferred learning style improves educational outcomes when teaching procedures. The authors sought to examine whether teaching to a student\u27s self-perceived learning style improved the acquisition of intravenous (IV) catheter placement skills. The authors hypothesized that matching a medical student\u27s preferred learning style with the instructor\u27s teaching style would increase the success of placing an IV catheter. METHODS: Using the VARK model (i.e., visual [V], auditory [A], read/write [R] and kinesthetic [K]), third-year medical students reported their self-perceived learning style and were subsequently randomized to instructors who were trained to teach according to a specific learning format (i.e., visual, auditory). Success was gauged by: 1) the placement of an IV on the first attempt and 2) the number of attempts made until an IV line was successfully placed. RESULTS: The average number of attempts in the matched learning style group was 1.53, compared to 1.64 in the unmatched learning style group; however, results were not statistically significant. Both matched and unmatched groups achieved a similar success rate (57 and 58 %, respectively). Additionally, a comparison of success between the unmatched and matched students within each learning style modality yielded no statistical significance. CONCLUSIONS: Results suggest that providing procedural instruction that is congruent with a student\u27s self-perceived learning style does not appear to improve outcomes when instructing students on IV catheter placement

Endurance training slows breast tumor growth in mice by suppressing Treg cells recruitment to tumors

BACKGROUND: Aerobic exercise has been shown to slow tumor progression in rodents and humans, but the mechanisms behind this effect are still unclear. Here we show that aerobic exercise in the form of chronic endurance training suppresses tumor recruitment of FoxP3+ Treg cells thus enhancing antitumor immune efficiency. METHODS: Adult wild-type and athymic BALB/c female mice were endurance-trained for 8 weeks. Circulating leukocytes as well as muscle and liver mtDNA copy number were compared to aged-matched concurrent sedentary controls to establish systemic effects. 4 T1 murine mammary tumor cells were injected subcutaneously to the 4th mammary pad at the end of the training period. Tumor growth and survival rates were compared, together with antitumor immune response. RESULTS: Exercised wild-type had 17% slower growth rate, 24% longer survival, and 2-fold tumor-CD+ 8/FoxP3+ ratio than sedentary controls. Exercised athymic BALB/c females showed no difference in tumor growth or survival rates when compared to sedentary controls. CONCLUSIONS: Cytotoxic T cells are a significant factor in endurance exercise-induced suppression of tumor growth. Endurance exercise enhances antitumor immune efficacy by increasing intratumoral CD8+/FoxP3+ ratio

Mermaids Show Card

Show card for Mermaids by Richard Serrano. This was a sculpture exhibition. April 16 - 26, 2001.https://digitalcommons.udallas.edu/mermaids_exhibit/1000/thumbnail.jp

Uso de video para cuantificar los patrones espacio-temporales de la actividad pesquera de los distintos sectores en los Sistemas de Agregadores de Peces de Puerto Rico

A key challenge in small-scale fisheries that use moored fish aggregating devices (mFADs) is the ability to accurately quantify multi-sector fishing activity through fishery-independent methods. Here, we present a novel fishery-independent assessment of multi-sector fishing activity associated with a newly developed open access mFAD programme off San Juan, Puerto Rico. We identified three fishing sectors (recreational, charter and commercial) and 158 individual fishing vessels that routinely operated in the vicinity of the mFADs. The results indicate that daytime fishing activity varied by time of day, day of week, location and sector. During fishing tournaments, the data revealed that fishing activity increased threefold; across monitoring periods, for-hire charter vessels were the most consistent day-to-day user segment, and recreational activity peaked on weekends. Our study represents a new technique for rapidly identifying and detecting multi-sector fishing activity near mFADs and highlights the potential to gather comparable data wherever mFADs are deployed. The results are used to discuss how this technique can be used to assess the performance of mFADs to identify sector overlap and guide management in determining deployment patterns and facilitate the design of cost-effective surveys to estimate mFAD vessel activity, and potentially catch, of mFAD-associated species.Un reto crucial en las pesquerías artesanales que utilizan los sistemas de agregadores de peces fijos (mFAD, por sus siglas en inglés) es el poder cuantificar con certeza la actividad pesquera multisectorial a través de métodos independientes de la pesca. En este estudio presentamos un innovador análisis independiente de la pesca para la actividad de pesca multisectorial asociada a los nuevos mFAD establecidos en Puerto Rico. Se identificaron 3 sectores pesqueros (recreacional, de alquiler y comercial) y 158 embarcaciones que rutinariamente pescaban alrededor de los mFAD. Los resultados muestran que la actividad pesquera diurna variaba por hora del día, día de la semana, lugar y sector. Durante torneos de pesca la actividad pesquera se triplicó, a lo largo de los periodos evaluados los botes de alquiler mostraron mayor consistencia por día y la actividad recreativa aumentó durante el fin de semana. Nuestro estudio plantea una nueva técnica para identificar rápidamente y detectar actividad multisectorial pesquera cerca de los mFAD y resalta el potencial de tomar datos comparables en otros lugares donde se coloquen los mFAD. Los resultados se utilizan para discutir cómo esta técnica puede ser utilizada para evaluar la ejecutoria de los mFAD, identificar solape de uso por varios sectores y guiar las decisiones en cuanto a los patrones para colocar los mFAD y facilitar el diseño de estudios costo efectivos para estimar la actividad de embarcaciones y el potencial de captura de peces alrededor de los mFAD

Combination therapy for severe portopulmonary hypertension in a child allows for liver transplantation

Severe PPHTN is a contraindication to liver transplantation and predicts an abysmal 5‐year outcome. It is defined as a resting mPAP >45 mm Hg with a mean pulmonary artery wedge pressure of 3 wood units in the setting of portal hypertension. There have been limited reports of successful treatment of PPHTN leading to successful liver transplantation in adults, and one reported use of monotherapy as a bridge to successful liver transplant in pediatrics. To our knowledge, we describe the first use of combination therapy as a successful bridge to liver transplantation in a pediatric patient with severe PPHTN. This report adds to the paucity of data in pediatrics on the use of pulmonary vasodilator therapy in patients with severe PPHTN as a bridge to successful liver transplantation. Early diagnosis in order to mitigate or avoid the development of irreversible pulmonary vasculopathy that would preclude candidacy for liver transplantation is crucial, but our report demonstrates that combination therapy can be administered safely, quickly, and may allow for successful liver transplantation in patients with severe PPHTN

Thermal and fluid dynamic optimization of a CPV-T receiver for solar co-generation applications: numerical modelling and experimental validation

Solar co-generation, i.e., the generation of electricity and heat in a single device by concentrating the sunbeams, has the potential to significantly increase the overall system performance. The main challenge is related to the cooling of solar cells. In order to do so, it is essential to reduce the thermal resistance between the cell and heat transfer fluid. This paper features the optimization procedure of a low-cost custom concentrated photovoltaic thermal (CPV-T) receiver for a parabolic trough collector using silicon solar cells. A finite volume model for the thermal process has been developed. Hence, a fluid dynamic thermal simulation of the receiver is presented. The optimized heat sink tube geometries have been manufactured and tested in a lab environment, allowing for a comparison between modelling and experimental test results. Three possible heat sink geometries have been designed and compared regarding their overall heat transfer coefficient with respect to the non-dimensional pumping power, i.e. the ratio between the overall transferred heat and the energy required for pumping. The overall heat transfer coefficient for a finned heat sink has been increased up to 60% with respect to a baseline case without fins under similar conditions.This project has received funding from SOLAR-ERA.NET Cofund 2 joint call undertaking under the European Union’s Horizon 2020 research and innovation programme. This work has also been supported by Scientific and Technological Research Council of Türkiye (TÜBİTAK) under grant number 219M028. The authors acknowledge the Heat and Environment Laboratory, Mechanical Engineering Department, METU, and the help of Bulent G. Akinoglu and Elsen Aydin. D. Santos acknowledges FI AGAUR-Generalitat de Catalunya fellowship (2022FI_B2_00173).Peer ReviewedPostprint (published version

Increased platelet expression of FcGammaRIIa and its potential impact on platelet reactivity in patients with end stage renal disease

<p>Abstract</p> <p>Background</p> <p>Increased platelet reactivity has been implicated in cardiovascular disease – the major cause of death in patients with end stage renal disease (ESRD). FcGammaRIIA is a component of glycoprotein VI and Ib-IX-V that mediate activation of platelets by collagen and von Willebrand factor. To determine whether expression of FcGammaRIIA impacts platelet reactivity we quantified its expression and platelet reactivity in 33 patients with ESRD who were undergoing hemodialysis.</p> <p>Methods</p> <p>Blood samples were obtained from patients immediately before hemodialysis and before administration of heparin. Platelet expression of FcGammaRIIA and the activation of platelets in response to low concentrations of convulxin (1 ng/ml, selected to mimic effects of collagen), thrombin (1 nM), adenosine diphosphate (ADP, 0.2 uM), or platelet activating factor (PAF, 1 nM) were determined with the use of flow cytometry in samples of whole blood anticoagulated with corn trypsin inhibitor (a specific inhibitor of Factor XIIa).</p> <p>Results</p> <p>Patients were stratified with respect to the median expression of FcGammaRIIA. Patients with high platelet expression of FcGammaRIIA exhibited 3-fold greater platelet reactivity compared with that in those with low expression in response to convulxin (p < 0.01) and 2-fold greater activation in response to thrombin, ADP, and PAF (p < 0.05 for each). For each agonist, expression of FcGammaRIIA correlated modestly but positively with platelet reactivity. The strongest correlation was with thrombin-induced activation (r = 0.6, p < 0.001).</p> <p>Conclusion</p> <p>Increased platelet reactivity in response to low concentrations of diverse agonists is associated with high expression of FcGammaRIIA and may contribute to an increased risk of thrombosis in patients with ESRD.</p

Contract Farming in the Mekong Delta's Rice Supply Chain: Insights from an Agent-Based Modeling Study

We would like to thank Michael Maes and the anonymous reviewers for their insightful and constructive feedback. The first author, H. K. Nguyen, would like to acknowledge support from an Australian Government Research Training Program scholarship to study a PhD degree in Computer Science at The University of Newcastle, Australia. R. Chiong is the corresponding author of this paper. The third author, M. Chica, is supported through the Ramón y Cajal program (RYC-2016-19800)In this paper, we use agent-based modeling (ABM) to study different obstacles to the expansion of contract rice farming in the context of Mekong Delta (MKD)'s rice supply chain. ABM is a bottom-up approach for modeling the dynamics of interactions among individuals and complex combinations of various factors (e.g., economic, social or environmental). Our agent-based contract farming model focuses on two critical components of contractual relationship, namely financial incentives and trust. We incorporate the actual recurrent fluctuations of spot market prices, which induce both contractor and farmer agents to renege on the agreement. The agent-based model is then used to predict emergent system-wide behaviors and compare counterfactual scenarios of different policies and initiatives on maintaining the contract rice farming scheme. Simulation results firstly show that a fully-equipped contractor who opportunistically exploits a relatively small proportion (less than 10%) of the contracted farmers in most instances can outperform spot market-based contractors in terms of average profit achieved for each crop. Secondly, a committed contractor who offers lower purchasing prices than the most typical rate can obtain better earnings per ton of rice as well as higher profit per crop. However, those contractors in both cases could not enlarge their contract farming scheme, since either farmers' trust toward them decreases gradually or their offers are unable to compete with the benefits from a competitor or the spot market. Thirdly, the results are also in agreement with the existing literature that the contract farming scheme is not a cost-effective method for buyers with limited rice processing capacity, which is a common situation among the contractors in the MKD region. These results yield significant insights into the difficulty in expanding the agricultural contracting program in the MKD's rice supply chain.Ramón y Cajal program (RYC-2016-19800