3,257 research outputs found
The Conformal Limit and Projective Structures
The non-abelian Hodge correspondence maps a polystable -Higgs bundle on a compact Riemann surface of genus to a connection that, in some cases, is the holonomy of a branched hyperbolic structure. Gaiotto's conformal limit maps the same bundle to a partial oper, that is, to a connection whose holonomy is that of a branched complex projective structure compatible with . In this article, we show how these are both instances of the same phenomenon: the family of connections appearing in the conformal limit can be understood as a family of complex projective structures, deforming the hyperbolic ones into the ones compatible with . We also show that, for zero Toledo invariant, this deformation is optimal, inducing a geodesic on Teichm & uuml;ller's space
Hybrid magnetic graphitic nanocomposites for catalytic wet peroxide oxidation applications
Fe3O4, with a lattice parameter a = 8.357 A and average particle size of 12.5 +/- 3.6 nm, was successfully encapsulated within a graphitic structure by a hierarchical co-assembly approach, followed by thermal annealing. The resulting material was denoted as MGNC-magnetic graphitic nanocomposite. MGNC possesses average core size of 109 +/- 35 nm (mainly composed by agglomerates of magnetic nanoparticles), stability up to 400 degrees C under oxidizing atmosphere, a micro-mesoporous structure with a fairly developed specific surface area (S-BET = 330 m(2) g(-1)) and neutral character (pH(PZC) = 7.1). Catalytic wet peroxide oxidation (CWPO) experiments performed with a 4-nitrophenol (4-NP)/Fe3O4 mass ratio fixed at 36.6, allowed to achieve high efficiency of catalyst usage throughout the wide range of 4-NP concentration considered (200 mg L-1-5 g L-1). The inclusion of Fe3O4 nanoparticles in a graphitic structure during the synthesis of MGNC was found to (i) enhance the catalytic activity in CWPO when compared to Fe3O4, due to increased adsorptive interactions between the surface of the catalyst and the pollutant molecules, while (ii) strongly limiting the leaching of Fe species from Fe3O4 to the treated water, due to the confinement effect caused by the carbon shell. As a result of these effects, unprecedented pollutant mass removals were obtained ranging from 5000 mg(-1) h(-1), when the CWPO process is performed with [4-NP](o) = 200 mg L-1 at pH = 3, to 1250 mgg(-1) h(-1), when [4-NP](o) = 5 g L-1. High efficiency of H2O2 consumption is obtained when MGNC is applied in the CWPO of 4 -NP solutions at pH = 3, with TOC removals per unit of H2O2 decomposed (n(H2O2)) in the range 64-100%. In addition, the MGNC catalyst is also active at pH = 6; in this case a pollutant mass removal of 2090 mg g(-1) h(-1) was obtained. Although MGNC partially deactivates through successive reusability cycles, the pollutant mass removal obtained at the end of the fourth cycle is still very high when 200 mg L-1 4-NP solutions are considered (4808 mg g(-1) h(-1), representing only a ca. 4% decrease when compared to the first cycle). A higher deactivation of the MGNC catalyst is observed when 5 gL(-1) 4-NP solutions are employed. Nevertheless, the pollutant mass removal obtained at the end of the third cycle is still high (551 mgg(-1) h(-1))
Computer-Generated Ovaries to Assist Follicle Counting Experiments
Precise estimation of the number of follicles in ovaries is of key importance in the field of reproductive biology, both from a developmental point of view, where follicle numbers are determined at specific time points, as well as from a therapeutic perspective, determining the adverse effects of environmental toxins and cancer chemotherapeutics on the reproductive system. The two main factors affecting follicle number estimates are the sampling method and the variation in follicle numbers within animals of the same strain, due to biological variability. This study aims at assessing the effect of these two factors, when estimating ovarian follicle numbers of neonatal mice. We developed computer algorithms, which generate models of neonatal mouse ovaries (simulated ovaries), with characteristics derived from experimental measurements already available in the published literature. The simulated ovaries are used to reproduce in-silico counting experiments based on unbiased stereological techniques; the proposed approach provides the necessary number of ovaries and sampling frequency to be used in the experiments given a specific biological variability and a desirable degree of accuracy. The simulated ovary is a novel, versatile tool which can be used in the planning phase of experiments to estimate the expected number of animals and workload, ensuring appropriate statistical power of the resulting measurements. Moreover, the idea of the simulated ovary can be applied to other organs made up of large numbers of individual functional units
A case of equine multicentric lymphoma: Clinical, microscopical, and molecular findings
Background: Although relatively uncommon, lymphoma is the most prevalent haematopoietic neoplasia in horses, and multicentric lymphoma remains the most common presentation of the disease. The pathogenesis of equine lymphoma is still poorly understood and the diagnosis is usually confirmed at an advanced stage of the disease, compromising the prognosis. This study investigated the clinical, pathological, and molecular features of a case of equine multicentric lymphoma.
Case description: An apparently healthy 5-year-old crossbreed mare hospitalized at the Centre of Animal Reproduction of Vairão, Portugal, suddenly presented clinical signs of supraorbital oedema and mandibular lymph node enlargement, developing fever, facial oedema, and generalized lymphadenopathy. The mare ended up dying twenty-four days after the first clinical signs due to multisystem organ failure. Haematological and biochemical analyses, necropsy, and microscopic and molecular evaluation of affected tissues were performed. At necropsy, the main findings were multiple multinodular lesions, distributed along the serous surface of oropharynx, trachea, pericardium, gastrointestinal tract, and mesentery. Microscopically, these consisted of solid proliferations of neoplastic round cells that exhibited immunopositivity for CD3 (T cells). Based on these findings, a medium-grade multicentric T-cell lymphoma was diagnosed.
Conclusion: There is still very little research regarding the molecular characterization of lymphoma in horses. As an entity itself is quite heterogeneous, it is important to describe the interspecies particularities to understand its development and behaviour.GFS (2022.14765.BD) acknowledges the Portuguese Foundation for Science and Technology (FCT), for financial support. IPATIMUP integrates the i3S Research Unit, which is partially supported by FCT
On the separation between RR Lyrae and Type II Cepheids and their importance for distance determination: the case of Cen
The separation between RR Lyrae (RRLs) and Type II Cepheid (T2Cs) variables based on their period is debated. Both types of variable stars are distance indicators and we aim to promote the use of T2Cs as distance indicators in synergy with RRLs. We adopted new and existing optical and Near-Infrared (NIR) photometry of \wcen~to investigate several diagnostics (colour-magnitude diagram, Bailey diagram, Fourier decomposition of the light curve, amplitude ratios) for their empirical separation. We found that the classical period threshold at 1 day is not universal and does not dictate the evolutionary stage: V92 has a period of 1.3 days but is likely to be still in its core Helium-burning phase, typical of RRLs. We also derived NIR Period-Luminosity relations and found a distance modulus of 13.650.07 (err.)0.01 () mag, in agreement with the recent literature. We also found that RRLs and T2Cs obey the same PL relations in the NIR. This equivalence gives the opportunity to adopt RRLs+T2Cs as an alternative to classical Cepheids to calibrate the extragalactic distance scale
Circulating endothelial cell-derived extracellular vesicles mediate the acute phase response and sickness behaviour associated with CNS inflammation.
Brain injury elicits a systemic acute-phase response (APR), which is responsible for co-ordinating the peripheral immunological response to injury. To date, the mechanisms responsible for signalling the presence of injury or disease to selectively activate responses in distant organs were unclear. Circulating endogenous extracellular vesicles (EVs) are increased after brain injury and have the potential to carry targeted injury signals around the body. Here, we examined the potential of EVs, isolated from rats after focal inflammatory brain lesions using IL-1β, to activate a systemic APR in recipient naïve rats, as well as the behavioural consequences of EV transfer. Focal brain lesions increased EV release, and, following isolation and transfer, the EVs were sequestered by the liver where they initiated an APR. Transfer of blood-borne EVs from brain-injured animals was also enough to suppress exploratory behaviours in recipient naïve animals. EVs derived from brain endothelial cell cultures treated with IL-1β also activated an APR and altered behaviour in recipient animals. These experiments reveal that inflammation-induced circulating EVs derived from endothelial cells are able to initiate the APR to brain injury and are sufficient to generate the associated sickness behaviours, and are the first demonstration that EVs are capable of modifying behavioural responses
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Impact of the Health Gym Program on hospital admissions for stroke in the state of Pernambuco, Brazil
This study aimed to evaluate the impact of the Health Gym Program (HGP) on hospital admissions for stroke in the state of Pernambuco, Brazil. This policy impact evaluation used a quasi-experimental approach consisting of a difference-in-differences estimator, weighted by propensity score matching to deal with potential confounding variables. The study comprised socioeconomic, demographic, and epidemiological data from official Brazilian databases from 2010 to 2019. The treatment group was composed of the 134 municipalities that implemented the HGP since 2011. The 51 municipalities that did not were allocated to the comparison group. The nearest neighbor algorithm (N5) was used to pair treatment and comparison group municipalities and create the weights to evaluate the average treatment effect on the treated (ATT) in the difference-in-differences estimator. In 2010, 2,771 people were hospitalized for stroke (0.51% of all hospitalizations) and in 2019, 11,542 (2%). Municipalities that implemented the HGP had 18.37% fewer hospitalizations than their counterparts in the comparison group. The program’s impact in reducing hospitalization rates was incrementally greater among men (ATT: -0.1932) and those aged 71 to 80 years (ATT: -0.1911). All results were statistically significant at the 5% level. The HGP reduced hospitalization for stroke in several population groups, but primarily in those whose underlying prevalence of stroke is highest, reinforcing the importance of public investments in health promotion policies designed to encourage lifestyle changes.Resumo: O estudo teve como objetivo avaliar o impacto do Programa Academia da Saúde (PAS) nas internações hospitalares por acidente vascular cerebral (AVC) no Estado de Pernambuco, Brasil. Esta avaliação
de impacto das políticas utilizou uma abordagem quase-experimental que consiste em um estimador de diferença-em-diferenças, ponderado
pelo pareamento por escore de propensão para lidar com possíveis fatores de confusão. O estudo foi composto por dados socioeconômicos, demográficos e epidemiológicos de bases de dados oficiais brasileiras entre os anos de 2010 e 2019. O grupo de tratamento foi composto pelos 134 municípios que implantaram o PAS a partir de 2011, e os 51
municípios que não implantaram foram alocados no grupo de comparação. O algoritmo do vizinho mais próximo (N5) foi utilizado para emparelhar
os municípios tratados e comparar aos municípios do grupo controle, criando os pesos que foram utilizados para avaliar o efeito médio do tratamento sobre o tratado (ATT) no estimador de diferença-
-em-diferenças. Houve 2.771 internações por AVC em 2010 (0,51% de todas as internações) e 11.542 (2%) em 2019. Os municípios que implementaram o PAS tiveram 18,37% menos internações em comparação
com seus homólogos no grupo de comparação. O impacto do programa na redução das taxas de internação foi maior entre os homens (ATT: -0,1932) e naqueles com idade entre 71 e 80 anos (ATT: -0,1911). Todos os resultados foram estatisticamente significativos em um nível de 5%. O
PAS reduziu a hospitalização por AVC em vários grupos populacionais, mas principalmente naqueles em que a prevalência subjacente de AVC é mais alta, reforçando a importância dos investimentos públicos em políticas de promoção da saúde destinadas a estimular mudanças nos estilos de vida.
Avaliação de Programas e Projetos de Saúde;
Doença Crônica; Promoção da Saúde; Pontuação
de Propensão; Acidente Vascular CerebralResumen: El objetivo de este trabajo es evaluar el impacto del Programa Academia de la Salud (PAS) en los ingresos hospitalarios por accidente cerebrovascular (ACV) en el estado de Pernambuco, Brasil. Esta evaluación del impacto de la política utilizó un enfoque cuasi-experimental que consiste en un estimador de diferencias en diferencias, ponderado por el emparejamiento de puntuación de propensión para hacer frente a posibles factores de confusión. El estudio incluyó datos socioeconómicos, demográficos y epidemiológicos de bases de datos oficiales brasileñas de 2010 a 2019. El grupo de tratamiento se compuso de los 134 municipios que implementaron el PAS a partir de 2011 y los 51 municipios que no lo hicieron se asignaron al grupo de comparación. Se utilizó el algoritmo del vecino más próximo (N5) para emparejar los municipios tratados y los del grupo de comparación y crear las ponderaciones que se emplearon para evaluar el efecto medio del tratamiento sobre los tratados (ATT) en el estimador de diferencias en diferencias. Hubo 2.771 hospitalizaciones por ACV en 2010 (0,51% de todas las hospitalizaciones) y 11.542 (2%) en 2019. Los municipios que aplicaron el PAS tuvieron un 18,37% menos de hospitalizaciones en comparación con sus homólogos del grupo de comparación. El impacto del programa en la reducción de las tasas de hospitalización fue gradualmente mayor entre los hombres (ATT: -0,1932) y entre las personas de 71 a 80 años (ATT: -0,1911). Todos los resultados fueron estadísticamente significativos al nivel del 5%. El PAS redujo la hospitalización por ACV en varios grupos de población, pero principalmente en aquellos en los que la prevalencia subyacente de ACV es mayor, lo que refuerza la importancia de las inversiones públicas en políticas de promoción de la salud diseñadas para impulsar cambios en los estilos de vida.
Evaluación de Programas y Proyectos de Salud;
Enfermedad Crónica; Promoción de la Salud;
Puntaje de Propensión; Accidente CerebrovascularPernambuco State Foundation for the Support of Science and Technology (FACEPE), and the Brazilian National Research Council (CNPq)
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