On the instability of Reissner-Nordstrom black holes in de Sitter backgrounds

Recent numerical investigations have uncovered a surprising result: Reissner-Nordstrom-de Sitter black holes are unstable for spacetime dimensions larger than 6. Here we prove the existence of such instability analytically, and we compute the timescale in the near-extremal limit. We find very good agreement with the previous numerical results. Our results may me helpful in shedding some light on the nature of the instability.Comment: Published in Phys.Rev.

Childhood Obesity Determinants of Childhood Overweight

Introduction The number of obese children has grown exponentially in the recent decades, which has been the subject of concern byseveral entities, health care and education. Thus we performed a framework, in theoretical terms, the concept of childhood obesity and its relationship with risk factors / protective, eating habits, physical activity and sedentary lifestyle, also recent studies with conclusions that are later confronted. Method Considering the issue under study, the participants in this study are children (n = 1424) born in the years 2006, 2007 and 2008, aged between 3 and 6 years enrolled in 2011–2012 school year in kindergartens districts of Viseu, Leiria, Évora and Vila Real - Portugal

Optimizing lab-scale wastewater treatment reactors operation for enhanced assays

Book of Abstracts of CEB Annual Meeting 2017[Excerpt] Wastewater treatment plants (WWTP) comprise a complex set of sequenced operations that ensure the safe discharge of water, previously contaminated by anthropogenic activities, into the environment. Roughly, these operations are divided in: preliminary treatment, primary treatment and secondary treatment. The secondary treatment is the most critical operation, encompassing a feeble equilibrium between physicochemical conditions and biological processes. It commonly consists in an aeration tank and a clarifier [1]. The microbial community present in the aeration tank is responsible for metabolizing most of the influent nutrient load. Pure oxygen, or air, is injected in this process to guarantee an adequate concentration of dissolved oxygen, in order to promote a rapid aerobic metabolism. Simultaneously preventing anoxic conditions, which denote a slower nutrient consumption and the generation of foul substances. Worldwide, the most commonly used microbial community for this process in the WWTP is activated sludge. Consisting of a highly complex community comprising bacteria, fungi, small protozoa and protozoa, the activated sludge “healthiness” is a critical factor for the efficiency of the wastewater treatment process. In addition, “healthy” activated sludge also possess a key physicochemical property for the downstream process of the aeration tank, namely, flocculation. In the clarifier the activated sludge flocs will sediment by the sole action of gravity, thus preventing a high microbial load in the effluent [2]. [...]info:eu-repo/semantics/publishedVersio

Semianalytical estimates of scattering thresholds and gravitational radiation in ultrarelativistic black hole encounters

Ultrarelativistic collisions of black holes are ideal gedanken experiments to study the nonlinearities of general relativity. In this paper we use semianalytical tools to better understand the nature of these collisions and the emitted gravitational radiation. We explain many features of the energy spectra extracted from numerical relativity simulations using two complementary semianalytical calculations. In the first calculation we estimate the radiation by a "zero-frequency limit" analysis of the collision of two point particles with finite impact parameter. In the second calculation we replace one of the black holes by a point particle plunging with arbitrary energy and impact parameter into a Schwarzschild black hole, and we explore the multipolar structure of the radiation paying particular attention to the near-critical regime. We also use a geodesic analogy to provide qualitative estimates of the dependence of the scattering threshold on the black hole spin and on the dimensionality of the spacetime.Comment: 29 pages, 19 figure, 6 tables, minor changes to match version in press in Phys.Rev.

Atitudes do enfermeiro em contexto de ensino clínico: uma revisão da literatura

Com o decorrer do Ensino Clínico torna-se crucial compreender de que modo as atitudes dos enfermeiros influenciam o desempenho dos alunos. Cuidados de excelência só podem ser assegurados com a passagem de testemunho do Enfermeiro para o aluno. Nesta linha, as atitudes que os enfermeiros supervisores apresentam, tornam-se o “espelho” e o reflexo do futuro profissional. O supervisor tem a capacidade de melhorar a qualidade da formação do estudante, sendo que este tem o dever de ser o catalisador da mudança. Um processo interactivo e dinâmico facilitador da aprendizagem experiencial que permite a melhoria e a continuidade dos cuidados

Impacto econômico da mastite em seis fazendas de Araxá, Minas Gerais.

Estimou-se o impacto econômico da ocorrência da mastite em seis fazendas da microrregião geográfica de Araxá, Minas Gerais, por intermédio dos registros contábeis. Os medicamentos empregados para mastite, entre maio de 1997 a maio de 1998, foram classificados em para tratamento e para prevenção. O número de quartos afetados com mastite clínica foi obtido da dosagem dos medicamentos para tratamento e, a partir deste, estimado o número de quartos subclínicos. Aos gastos com medicamentos para mastite, foram somados os custos de reposição de animais, serviços veterinários, mão-de-obra extra para tratamento e prevenção e as perdas, em reais, provocadas pela redução da produção de leite e descarte do leite por causa de mastite (obtidas da literatura). O percentual de quartos afetados por mastite clínica foi 4,89% e a relação quarto subclínico/ quarto clínico foi de 8,81. Os custos e perdas totais com mastite foram equivalentes à US$ 126 por vaca em lactação por ano. Deste total, 60% foram devido à redução na produção provocada por mastite subclínica, 15% com redução provocada por mastite clínica, 12% com perdas por quartos afuncionais, 6% com mão-de-obra extra, 2% com reposição de animais, 2% com medicamentos, 2% com descarte de leite por causa de tratamento e 2% com serviços veterinários

A Critical Perspective on 3D Liver Models for Drug Metabolism and Toxicology Studies

The poor predictability of human liver toxicity is still causing high attrition rates of drug candidates in the pharmaceutical industry at the non-clinical, clinical, and post-marketing authorization stages. This is in part caused by animal models that fail to predict various human adverse drug reactions (ADRs), resulting in undetected hepatotoxicity at the non-clinical phase of drug development. In an effort to increase the prediction of human hepatotoxicity, different approaches to enhance the physiological relevance of hepatic in vitro systems are being pursued. Three-dimensional (3D) or microfluidic technologies allow to better recapitulate hepatocyte organization and cell-matrix contacts, to include additional cell types, to incorporate fluid flow and to create gradients of oxygen and nutrients, which have led to improved differentiated cell phenotype and functionality. This comprehensive review addresses the drug-induced hepatotoxicity mechanisms and the currently available 3D liver in vitro models, their characteristics, as well as their advantages and limitations for human hepatotoxicity assessment. In addition, since toxic responses are greatly dependent on the culture model, a comparative analysis of the toxicity studies performed using two-dimensional (2D) and 3D in vitro strategies with recognized hepatotoxic compounds, such as paracetamol, diclofenac, and troglitazone is performed, further highlighting the need for harmonization of the respective characterization methods. Finally, taking a step forward, we propose a roadmap for the assessment of drugs hepatotoxicity based on fully characterized fit-for-purpose in vitro models, taking advantage of the best of each model, which will ultimately contribute to more informed decision-making in the drug development and risk assessment fields.This research has been supported by FCT (Portugal) through the research grants and scholarship PTDC/MED-TOX/29183/2017, UIDB/04138/2020, UIDP/04138/2020, and SFRH/BD/144130/2019 to JR and by the H2020, European Commission, though the MSCA-IF-EF-ST – Standard EF to MC (GA-845147-LIV-AD-ON-A-CHIP). Conflict of Interestinfo:eu-repo/semantics/publishedVersio

Are the effects induced by increased temperature enhanced in Mytilus galloprovincialis submitted to air exposure?

Intertidal mussel species are frequently exposed to changes of environmental parameters related to tidal regimes that include a multitude of stressors that they must avoid or tolerate by developing adaptive strategies. In particular, besides air exposure during low tides, intertidal mussels are also subjected to warming and, consequently, to higher risk of desiccation. However, scarce information is available regarding the responses of mussels to tidal regimes, particularly in the presence of other stressors such as increased temperature. Investigating the impacts of such combination of conditions will allow to understand the possible impacts that both factors interaction may generate to these intertidal organisms. To this end, the present study evaluated the impacts of different temperatures (18 ºC and 21 ºC) on Mytilus galloprovincialis when continuously submersed or exposed to a tidal regime for 14 days. Results showed that in mussels exposed to increased temperature under submersion conditions, the stress induced was enough to activate mussels’ antioxidant defenses (namely glutathione peroxidase, GPx), preventing oxidative damage (lipid peroxidation, LPO; protein carbonylation, PC). In mussels exposed to tides at control temperature, metabolic capacity increased (electron transport system activity, ETS), and GPx was induced, despite resulting in increased LPO levels. Moreover, the combination of tides and temperature increase led to a significant decrease of lipid (LIP) content, activation of antioxidant defenses (superoxide dismutase, SOD; GPx) and increase of oxidized glutathione (GSSG), despite these mechanisms were not sufficient to prevent increased cellular damage. Therefore, the combination of increased temperature and air exposure induced higher oxidative stress in mussels. These findings indicate that increasing global warming could be more impacting to intertidal organisms compared to organisms continuously submersed. Furthermore, our results indicate that air exposure can act as a confounding factor when assessing the impacts of different stressors in organisms living in coastal systemspublishe

The potential use of biosurfactants as contact lenses coating agents

Fundação para a Ciência e a Tecnologia (FCT