An analytical framework for a consensus-based global optimization method

In this paper we provide an analytical framework for investigating the efficiency of a consensus-based model for tackling global optimization problems. This work justifies the optimization algorithm in the mean-field sense showing the convergence to the global minimizer for a large class of functions. Theoretical results on consensus estimates are then illustrated by numerical simulations where variants of the method including nonlinear diffusion are introduced

Collagen microarchitecture mechanically controls myofibroblast differentiation.

Altered microarchitecture of collagen type I is a hallmark of wound healing and cancer that is commonly attributed to myofibroblasts. However, it remains unknown which effect collagen microarchitecture has on myofibroblast differentiation. Here, we combined experimental and computational approaches to investigate the hypothesis that the microarchitecture of fibrillar collagen networks mechanically regulates myofibroblast differentiation of adipose stromal cells (ASCs) independent of bulk stiffness. Collagen gels with controlled fiber thickness and pore size were microfabricated by adjusting the gelation temperature while keeping their concentration constant. Rheological characterization and simulation data indicated that networks with thicker fibers and larger pores exhibited increased strain-stiffening relative to networks with thinner fibers and smaller pores. Accordingly, ASCs cultured in scaffolds with thicker fibers were more contractile, expressed myofibroblast markers, and deposited more extended fibronectin fibers. Consistent with elevated myofibroblast differentiation, ASCs in scaffolds with thicker fibers exhibited a more proangiogenic phenotype that promoted endothelial sprouting in a contractility-dependent manner. Our findings suggest that changes of collagen microarchitecture regulate myofibroblast differentiation and fibrosis independent of collagen quantity and bulk stiffness by locally modulating cellular mechanosignaling. These findings have implications for regenerative medicine and anticancer treatments

Stirring and mixing : 1999 Program of Summer Study in Geophysical Fluid Dynamics

The central theme of the 1999 GFD Program was the stirring, transport, reaction and mixing of passive and active tracers in turbulent, stratified, rotating fluids. The problem of mixing in fluids has applications in areas ranging from oceanography to engineering and astrophysics. In geophysical settings, mixing spans and unites a broad range of scales -- from micrometers to megameters. The mixing of passive tracers is of fundamental importance in environmental and industrial problems, such as pollution, and in determining the large-scale heat and salt balance of the worlds oceans. The transport of active tracers, on the other hand, such as vorticity, plays a key role in the turbulence that occurs in most geophysical and astrophysical fluids. William R. Young (Scripps Institution of Oceanography) gave a series of principal lectures, the notes of which as taken by the fellows, appear in this volume. Report of the projects of the student fellows makes up the second half of this volume.Funding was provided by the National Science Foundation under Grant No. OCE-9810647 and the Office of Naval Research under Grant No. NOO0l4-97-1-0934

Evaluation of the fungitoxic activity and isolation of alloaromadendrene - 4α, 10 β - diol in Hypericum cordatum

The Hypericum cordatum is a species of the Brazilian Cerrado that was selected in a screening of plants with fungitoxic activities. The aim of this work was to isolate and identify the compounds with antifungal activity in leaf extracts in dichloromethane. For this end, the powder made from the leaves of the plants was submitted to exhaustive extraction with petroleum ether and dichloromethane. The extract in dichloromethane and the active fractions were submitted to bioassay-guided fractionation in Sephadex LH - 20 column, respectively, with the following eluents chloroform:methanol (1:1) and a gradient of hexane:dichlorometane (1:4); dichloromethane:acetone (3:3 and 1:4), methanol and water. Afterward, the fractions that showed some activity were submitted to preparative thin layer chromatography of silica gel GF254 and the material with the greatest mass was submitted to semi-preparative HPLC. The active fraction obtained was analyzed by ¹H NMR, and the main component identified was alloaromadendrene-4α-10β - diol. We may then conclude that this is one of the compounds responsible for the fungitoxic activity of Hypericum cordatum.Hypericum cordatum é uma espécie do cerrado que foi selecionada em triagem de plantas com atividade fungitóxica. O objetivo do presente trabalho foi isolar e identificar compostos com atividade antifúngica em extratos de folhas em diclorometano. O pó das folhas das plantas foi submetido à extração exaustiva com éter de petróleo e diclorometano. O extrato em diclorometano, e as frações ativas, foram submetidos à fracionamentos biomonitorados em coluna de Sephadex LH-20, respectivamente, com os eluentes clorofórmio:metanol (1:1) e com um gradiente de hexano:diclorometano (1:4); diclorometano:acetona (3:2 e 1:4), metanol, e água. As frações que mostraram atividade foram submetidas à cromatografia em camada delgada preparativa de sílica gel GF254, sendo que o material de maior massa foi analisado em CLAE semipreparativa. A fração ativa foi analisada por RMN de ¹H, tendo sido identificado o aloaromadendrano - 4α -10β - diol como componente principal da fração. Conclui-se, portanto, que este é um dos compostos responsáveis pela atividade fungitóxica de Hypericum cordatum.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Instituto de Botânica Núcleo de Pesquisa em Fisiologia e BioquímicaUniversidade Federal de São Paulo (UNIFESP) Departamento de Ciências Exatas e da TerraUNIFESP, Depto. de Ciências Exatas e da TerraSciEL

Risk perception, safer sex practices and PrEP enthusiasm: Barriers and facilitators to oral HIV pre-exposure prophylaxis in Black African and Black Caribbean women in the UK

Objectives: UK Black African/Black Caribbean women remain disproportionately affected by HIV. Although oral pre-exposure prophylaxis (PrEP) could offer them an effective HIV prevention method, uptake remains limited. This study examined barriers and facilitators to PrEP awareness and candidacy perceptions for Black African/Black Caribbean women to help inform PrEP programmes and service development. Methods: Using purposive sampling through community organisations, 32 in-depth, semi-structured interviews were conducted with Black African/Black Caribbean women living in London and Glasgow between June and August 2018. Participants (aged 19–63) included women of varied HIV statuses to explore perceptions of sexual risk and safer sex, sexual health knowledge and PrEP attitudes. A thematic analysis guided by the Social Ecological Model was used to explore how PrEP perceptions intersected with wider safer sex understandings and practices. Results: Four key levels of influence shaping safer sex notions and PrEP candidacy perceptions emerged: personal, interpersonal, perceived environment and policy. PrEP-specific knowledge was low and some expressed distrust in PrEP. Many women were enthusiastic about PrEP for others but did not situate PrEP within their own safer sex understandings, sometimes due to difficulty assessing their own HIV risk. Many felt that PrEP could undermine intimacy in their relationships by disrupting the shared responsibility implicit within other HIV prevention methods. Women described extensive interpersonal networks that supported their sexual health knowledge and shaped their interactions with health services, though these networks were influenced by prevailing community stigmas. Conclusions: Difficulty situating PrEP within existing safer sex beliefs contributes to limited perceptions of personal PrEP candidacy. To increase PrEP uptake in UK Black African/Black Caribbean women, interventions will need to enable women to advance their knowledge of PrEP within the broader context of their sexual health and relationships. PrEP service models will need to include trusted ‘non-sexual health-specific’ community services such as general practice

Observation of pseudo two dimensional electron transport in the rock salt type topological semimetal LaBi

Topological insulators are characterized by an inverted band structure in the bulk and metallic surface states on the surface. In LaBi, a semimetal with a band inversion equivalent to a topological insulator, we observe surface state like behavior in the magnetoresistance. The electrons responsible for this pseudo two dimensional transport, however, originate from the bulk states rather topological surface states, which is witnessed by the angle dependent quantum oscillations of the magnetoresistance and ab initio calculations. As a consequence, the magnetoresistance exhibits strong anisotropy with large amplitude (~ 10^5 %).Comment: 21 pages, 4 figures and supplementary informatio

Gestión burocrática de entidades gubernamentales en organizaciones pymes durante los años 2016-2020: una revisión de la literatura científica

Esta investigación realizada sobre “Gestión burocrática en Entidades Gubernamentales en Organizaciones pymes durante los años 2016-2020”, tiene como fin saber identificar las diferentes barreras y hacer mejoras para una nueva implementación dentro del ámbito legal, así los emprendedores puedan entender y aplicar en la vida real y sepan cómo poder organizarse y desenvolverse. Sobre todo, poniendo en operatividad la creación de una empresa cual sea su giro, siempre que esté dentro de las normas vigentes de cada país. Para poder identificar distintos estudios, artículos relaciones con la gestión, burocracia, organizaciones y pymes, se utilizó buscadores confiables y certeros que nos den información de la realidad de la problemática a investigar. En el Perú, como en otros países la burocracia siempre ha existido desde los tiempos remotos, pero en diferentes escenarios, es por ello, que con el paso del tiempo se fueron adecuando y mejorando para distintos sectores laborales. Otras de las variables constantes que existe y que no puede pasar la barrera de la burocracia es la informalidad, se sabe que el principal objetivo es poder gestionar, organizar de manera correcta, en involucrar a la informalidad a poder pasar la barrera burocrática, pero para ello, se debe definir múltiples formas de acceso a información y distintos beneficios para poder reagrupar e insertar a la sociedad comercial para que este refleje un aporte dentro de cada país. Dentro del trabajo a investigar queremos identificar puntos de alta relevancia que pueda aportar una significativa mejora en su aplicación dentro del ámbito a desarrollarse

Associations of physical inactivity and COVID-19 outcomes among subgroups

Introduction Physical activity before COVID-19 infection is associated with less severe outcomes. The study determined whether a dose‒response association was observed and whether the associations were consistent across demographic subgroups and chronic conditions. Methods A retrospective cohort study of Kaiser Permanente Southern California adult patients who had a positive COVID-19 diagnosis between January 1, 2020 and May 31, 2021 was created. The exposure was the median of at least 3 physical activity self-reports before diagnosis. Patients were categorized as follows: always inactive, all assessments at 10 minutes/week or less; mostly inactive, median of 0–60 minutes per week; some activity, median of 60–150 minutes per week; consistently active, median>150 minutes per week; and always active, all assessments>150 minutes per week. Outcomes were hospitalization, deterioration event, or death 90 days after a COVID-19 diagnosis. Data were analyzed in 2022. Results Of 194,191 adults with COVID-19 infection, 6.3% were hospitalized, 3.1% experienced a deterioration event, and 2.8% died within 90 days. Dose‒response effects were strong; for example, patients in the some activity category had higher odds of hospitalization (OR=1.43; 95% CI=1.26, 1.63), deterioration (OR=1.83; 95% CI=1.49, 2.25), and death (OR=1.92; 95% CI=1.48, 2.49) than those in the always active category. Results were generally consistent across sex, race and ethnicity, age, and BMI categories and for patients with cardiovascular disease or hypertension. Conclusions There were protective associations of physical activity for adverse COVID-19 outcomes across demographic and clinical characteristics. Public health leaders should add physical activity to pandemic control strategies