11,646 research outputs found
Access to diagnosis and treatment of Chagas disease/infection in endemic and non-endemic countries in the XXI century.
In this article, Médicos Sin Fronteras (MSF) Spain faces the challenge of selecting, piecing together, and conveying in the clearest possible way, the main lessons learnt over the course of the last seven years in the world of medical care for Chagas disease. More than two thousand children under the age of 14 have been treated; the majority of whom come from rural Latin American areas with difficult access. It is based on these lessons learnt, through mistakes and successes, that MSF advocates that medical care for patients with Chagas disease be a reality, in a manner which is inclusive (not exclusive), integrated (with medical, psychological, social, and educational components), and in which the patient is actively followed. This must be a multi-disease approach with permanent quality controls in place based on primary health care (PHC). Rapid diagnostic tests and new medications should be available, as well as therapeutic plans and patient management (including side effects) with standardised flows for medical care for patients within PHC in relation to secondary and tertiary level, inclusive of epidemiological surveillance systems
Convergence of the forward-backward algorithm: beyond the worst-case with the help of geometry
We provide a comprehensive study of the convergence of the forward-backward algorithm under suitable geometric conditions, such as conditioning or Łojasiewicz properties. These geometrical notions are usually local by nature, and may fail to describe the fine geometry of objective
functions relevant in inverse problems and signal processing, that have a nice behaviour on manifolds, or sets open with respect to a weak topology. Motivated by this observation, we revisit those
geometric notions over arbitrary sets. In turn, this allows us to present several new results as well
as collect in a unified view a variety of results scattered in the literature. Our contributions include
the analysis of infinite dimensional convex minimization problems, showing the first Łojasiewicz
inequality for a quadratic function associated to a compact operator, and the derivation of new linear rates for problems arising from inverse problems with low-complexity priors. Our approach
allows to establish unexpected connections between geometry and a priori conditions in inverse
problems, such as source conditions, or restricted isometry properties
Implicit regularization with strongly convex bias: Stability and acceleration
Implicit regularization refers to the property of optimization algorithms to be biased towards a certain class of solutions. This property is relevant to understand the behavior of modern machine learning algorithms as well as to design efficient computational methods. While the case where the bias is given by a Euclidean norm is well understood, implicit regularization schemes for more general classes of biases are much less studied. In this work, we consider the case where the bias is given by a strongly convex functional, in the context of linear models, and data possibly corrupted by noise. In particular, we propose and analyze accelerated optimization methods and highlight a trade-off between convergence speed and stability. Theoretical findings are complemented by an empirical analysis on high-dimensional inverse problems in machine learning and signal processing, showing excellent results compared to the state of the art
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Characterization of between-group inequality of longevity in European Union countries
Comparisons of differential survival by country are useful in many domains. In the area of public policy, they help policymakers and analysts assess how much various groups benefit from public programs, such as social security and health care. In financial markets and especially for actuaries, they are important for designing annuities and life insurance products. This paper presents a method for clustering information about differential mortality by country. The approach is then used to group mortality surfaces for European Union (EU) countries. The aim of this paper is to measure between-group inequality in mortality experience in EU countries through a range of mortality indicators. Additionally, the indicators permit the characterization of each group. It is important to take into account characteristics such as sex; therefore, this study differentiates between males and females in order to detect whether their patterns and characterizations are different. It is concluded that there are clear differences in mortality between the east and west of the EU that are more important than the traditional south-north division, with a significant disadvantage for Eastern Europe, and especially for males in Baltic countries. We find that the mortality indicators have evolved in all countries in such a way that the gap between groups has been maintained, both in terms of the differences in mortality levels and variability
The Snapshot Hubble U-Band Cluster Survey (SHUCS) II. Star Cluster Population of NGC 2997
We study the star cluster population of NGC 2997, a giant spiral galaxy
located at 9.5 Mpc and targeted by the Snapshot Hubble U-band Cluster Survey
(SHUCS). Combining our U-band imaging from SHUCS with archival BVI imaging from
HST, we select a high confidence sample of clusters in the circumnuclear ring
and disk through a combination of automatic detection procedures and visual
inspection. The cluster luminosity functions in all four filters can be
approximated by power-laws with indices of to . Some deviations
from pure power-law shape are observed, hinting at the presence of a high-mass
truncation in the cluster mass function. However, upon inspection of the
cluster mass function, we find it is consistent with a pure power-law of index
despite a slight bend at M. No
statistically significant truncation is observed. From the cluster age
distributions, we find a low rate of disruption () in both the
disk and circumnuclear ring. Finally, we estimate the cluster formation
efficiency () over the last 100 Myr in each region, finding %
for the disk, % for the circumnuclear ring, and % for the
entire UBVI footprint. This study highlights the need for wide-field UBVI
coverage of galaxies to study cluster populations in detail, though a small
sample of clusters can provide significant insight into the characteristics of
the population.Comment: 31 pages, 9 figures, accepted to the A
Studying the evolution in time of bimetallic nanoparticles morphology by Cyclic Voltammetry
Over the last decades, bimetallic nanosized systems have attracted more and more interest thanks to their novel optical, catalytic, magnetic, and sensing properties, often different from the ones of their monometallic counterparts. Studies directed towards the size, shape, composition, and functionalization of the bimetallic nanoparticles are optimized to design sophisticated materials for the intended applications. Considering these facts, it is important to evaluate not only the type and the quantity of the two metals involved, but also their morphological distribution (e.g. alloy or core-shell). Characterization techniques normally used to investigate bimetallic systems are HR-TEM and EXAFS, very expensive and not so easily accessible. Recently, electrochemistry has been employed as alternative or complementary, low-cost, efficient technique with very promising results, allowing the discrimination between alloyed and perfect or defective core-shell systems after their synthesis. A further achievement is the possibility to follow step by step the formation morphology of these nanomaterials during their synthetic procedure. In the present work, we present a study on Au-Pt bimetallic nanoparticles, in form of alloy or core-shell. Cyclovoltammetry (CV) is used as a fast, low-cost and simple screening technique to distinguish the general composition of the sample and to understand the evolution in time of the systems morphology during their synthesis. An additional advantage is the possibility to conduct the study of the material simply in liquid form, without the need of using solid supports, as normally required by other characterization techniques. Interesting results are obtained for Au-based bimetallic samples, gaining information in accordance with TEM images and EXAFS spectra. This fact moves the interest towards the study of other bimetallic systems, to be used in catalytic, electrocatalytic and electroanalytical applications
Multiplicação in vitro de amoreira-preta cultivar Brazos.
A micropropagação da amoreira-preta pode gerar plantas livres de vírus e em curto espaço de tempo. Com o objetivo de aprimorar técnicas de micropropagação de amoreira-preta cultivar Brazos (Rubus idaeus L.), segmentos nodais, oriundos de plântulas preestabelecidas in vitro foram excisados e inoculados em meio WPM (0, 50, 100, 150 e 200%), suplementado com diferentes concentrações de BAP (0; 0,5; 1,0; 2,0 e 4,0 mg L-1). Após a inoculação, os explantes foram transferidos para sala de crescimento a 27±1ºC, irradiância de 35 mmol m 2 s 1 e fotoperíodo de 16 horas, onde permaneceram por 60 dias. O delineamento experimental utilizado foi inteiramente casualizado, utilizando-se de quatro repetições com quatro explantes cada. Maior número de brotos foi proporcionado com 1,0 mg L-1 de BAP associado a 100% de meio WPM e maior comprimento médio dos brotos após 60 dias foi verificado em 1,0 mg L-1 de BAP associado a 200% de meio WPM. Maior peso de matéria seca da parte aérea foi obtido em meio WPM 200% acrescido de 0,5 mg L-1 de BAP
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