691 research outputs found
Gravity with extra dimensions and dark matter interpretation: Phenomenological example via Miyamoto-Nagai galaxy
A configuration whose density profile coincides with the Newtonian potential
for spiral galaxies is constructed from a 4D isotropic metric plus extra
dimensional components. A Miyamoto-Nagai ansatz is used to solve Einstein
equations. The stable rotation curves of such system are computed and, without
fitting techniques, we recover with accuracy the observational data for flat or
not asymptotically flat galaxy rotation curves. The density profiles are
reconstructed and compared to that obtained from the Newtonian potential.Comment: 10 pages, 10 figures, submitted to Brazilian Journal of Physic
Development and exploratory cluster-randomised opportunistic trial of a theory-based intervention to enhance physical activity among adolescents
Peer reviewedPostprin
Intravenous immunoglobulin and Sjögren Syndrome
A síndrome de Sjögren (SS) é uma patologia auto-imune com incidência e prevalência importantes, manifestações clínicas variadas
e critérios diagnósticos bem definidos. Áreas como os seus mecanismos fisiopatológicos e novas estratégias terapêuticas têm merecido atenção crescente. A imunoglobulina intravenosa (IgIV) está indicada para o tratamento de várias entidades nosológicas, sendo crescente a investigação acerca dos seus mecanismos de acção, nomeadamente sobre a actividade imunitária. O seu espectro de indicações terapêuticas continua altamente
controverso mas tem vindo a expandir-se, sobretudo no âmbito da auto-imunidade. Existem apenas alguns casos descritos de
utilização da IgIV no tratamento da SS, principalmente quando se apresenta com manifestações neurológicas. Apresentamos uma revisão da indicação do uso da IgIV na SS, fazendo uma análise dos resultados de relatos de casos da sua utilização, entretanto publicados. A IgIV parece ser uma opção terapêutica a ter em conta na SS. Segundo o que se sabe, à data, será uma opção terapêutica, de segunda linha, para os
casos com manifestações extraglandulares graves refractários à terapêutica convencional
Oesophageal ulcers in a patient with human immunodeficiency vírus infection
Apresenta-se o caso de um homem de 22 anos
com úlceras esofágicas e dermite seborreica,
como primeiras manifestações de infecção por
vírus da imunodeficiência humana (HIV).
Revê-se a literatura sobre úlceras esofágicas, em doentes com e sem infecção por HIV
Realistic loophole-free Bell test with atom-photon entanglement
The establishment of nonlocal correlations, obtained through the violation of
a Bell inequality, is not only important from a fundamental point of view, but
constitutes the basis for device-independent quantum information technologies.
Although several nonlocality tests have been performed so far, all of them
suffered from either the locality or the detection loopholes. Recent studies
have suggested that the use of atom-photon entanglement can lead to Bell
inequality violations with moderate transmission and detection efficiencies. In
this paper we propose an experimental setup realizing a simple atom-photon
entangled state that, under realistic experimental parameters available to
date, achieves a significant violation of the Clauser-Horn-Shimony-Holt
inequality. Most importantly, the violation remains when considering typical
detection efficiencies and losses due to required propagation distances.Comment: 21 pages, 5 figures, 3 table, to appear in Nature Com
Absolutely continuous invariant measures for random non-uniformly expanding maps
We prove existence of (at most denumerable many) absolutely continuous
invariant probability measures for random one-dimensional dynamical systems
with asymptotic expansion. If the rate of expansion (Lyapunov exponents) is
bounded away from zero, we obtain finitely many ergodic absolutely continuous
invariant probability measures, describing the asymptotics of almost every
point.
We also prove a similar result for higher-dimensional random non-uniformly
expanding dynamical systems. The results are consequences of the construction
of such measures for skew-products with essentially arbitrary base dynamics and
asymptotic expansion along the fibers. In both cases our method deals with
either critical or singular points for the random maps.Comment: 30 pages; 2 figures. Keywords: non-uniform expansion, random
dynamics, slow recurrence, singular and critical set, absolutely continuous
invariant measures, skew-product. To appear in Math Z, 201
ATENA–A Novel Rapidly Manufactured Medical Invasive Ventilator Designed as a Response to the COVID-19 Pandemic: Testing Protocol, Safety, and Performance Validation
Background: The urgent need for mechanical ventilators to support respiratory insufficiency due to SARS-CoV-2 led to a worldwide effort to develop low-cost, easily assembled, and locally manufactured ventilators. The ATENA ventilator project was developed in a community-based approach targeting the development, prototyping, testing, and decentralized manufacturing of a new mechanical ventilator. Objective: This article aims to demonstrate ATENA's adequate performance and safety for clinical use. Material: ATENA is a low-cost ventilator that can be rapidly manufactured, easily assembled, and locally produced anywhere in the world. It was developed following the guidelines and requirements provided by European and International Regulatory Authorities (MHRA, ISO 86201) and National Authorities (INFARMED). The device was thoroughly tested using laboratory lung simulators and animal models. Results: The device meets all the regulatory requirements for pandemic ventilators. Additionally, the pre-clinical experiences demonstrated security and adequate ventilation and oxygenation, in vivo. Conclusion: The ATENA ventilator had a good performance in required tests in laboratory scenarios and pre-clinical studies. In a pandemic context, ATENA is perfectly suited for safely treating patients in need of mechanical ventilation.Financial support and sponsorship by CEiiA, INOV4COVID program, donations from scientific patronage, and commercial sales
Portuguese-Brazilian Evidence-Based Guideline on the Management of Hyperglycemia in Type 2 Diabetes Mellitus
Background: In current management of type 2 diabetes (T2DM), cardiovascular and renal prevention have become important targets to be achieved. In this context, a joint panel of four endocrinology societies from Brazil and Portugal was established to develop an evidence-based guideline for treatment of hyperglycemia in T2DM.
Methods: MEDLINE (via PubMed) was searched for randomized clinical trials, meta-analyses, and observational studies related to diabetes treatment. When there was insufficient high-quality evidence, expert opinion was sought. Updated positions on treatment of T2DM patients with heart failure (HF), atherosclerotic CV disease (ASCVD), chronic kidney disease (CKD), and patients with no vascular complications were developed. The degree of recommendation and the level of evidence were determined using predefined criteria.
Results and conclusions: In non-pregnant adults, the recommended HbA1c target is below 7%. Higher levels are recommended in frail older adults and patients at higher risk of hypoglycemia. Lifestyle modification is recommended at all phases of treatment. Metformin is the first choice when HbA1c is 6.5-7.5%. When HbA1c is 7.5-9.0%, dual therapy with metformin plus an SGLT2i and/or GLP-1RA (first-line antidiabetic agents, AD1) is recommended due to cardiovascular and renal benefits. If an AD1 is unaffordable, other antidiabetic drugs (AD) may be used. Triple or quadruple therapy should be considered when HbA1c remains above target. In patients with clinical or subclinical atherosclerosis, the combination of one AD1 plus metformin is the recommended first-line therapy to reduce cardiovascular events and improve blood glucose control. In stable heart failure with low ejection fraction ( 30 mL/min/1.73 m2, metformin plus an SGLT-2i is recommended to reduce cardiovascular mortality and heart failure hospitalizations and improve blood glucose control. In patients with diabetes-associated chronic kidney disease (CKD) (eGFR 30-60 mL/min/1.73 m2 or eGFR 30-90 mL/min/1.73 m2 with albuminuria > 30 mg/g), the combination of metformin and an SGLT2i is recommended to attenuate loss of renal function, reduce albuminuria and improve blood glucose control. In patients with severe renal failure, insulin-based therapy is recommended to improve blood glucose control. Alternatively, GLP-1RA, DPP4i, gliclazide MR and pioglitazone may be considered to reduce albuminuria. In conclusion, the current evidence supports individualizing anti-hyperglycemic treatment for T2DM.info:eu-repo/semantics/publishedVersio
Physical, Psychological and Emotional Benefits of Green Physical Activity: An Ecological Dynamics Perspective
© 2015 Springer International Publishing Switzerland Increasing evidence supports the multiple benefits to physical, psychological and emotional wellbeing of green physical activity, a topic of increasing interest in the past decade. Research has revealed a synergistic benefit of green physical activity, which includes all aspects of exercise and physical activity in the presence of nature. Our theoretical analysis suggests there are three distinct levels of engagement in green physical activity, with each level reported to have a positive effect on human behaviours. However, the extent to which each level of green physical activity benefits health and wellbeing is assumed to differ, requiring confirmation in future research. This elucidation of understanding is needed because previous literature has tended to focus on recording empirical evidence rather than developing a sound theoretical framework to understand green physical activity effects. Here we propose an ecological dynamics rationale to explain how and why green physical activity might influence health and wellbeing of different population groups. This framework suggests a number of unexplored, interacting constraints related to types of environment and population groups, which shape reported levels of benefit of green physical activity. Further analysis is needed to clarify the explicit relationship between green physical activity and health and wellbeing, including levels of engagement, types of environmental constraints, levels of physical activity, adventure effects, skill effects and sampling of different populations
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