4,400 research outputs found
Northern areas as refugia for temperate species under current climate warming: Atlantic salmon (Salmo salar L.) as a model in Northern Europe
This is the author accepted manuscript. The final version is available from Wiley via the DOI in this recordIn this work, patterns of geographical genetic diversity in Atlantic salmon Salmo salar were studied across the whole Atlantic arc, as well as whether patterns (and thus genetic population structure) were affected by water temperatures. Salmo salar populations were here characterized using microsatellite loci and then analysed in the light of ocean surface temperature data from across the region. Analysis showed the presence of a latitudinal cline of genetic variability (higher in northern areas) and water temperatures (sea surface temperatures) determining genetic population structure (the latter in combination with genetic drift in southern populations). Under the current global change scenario, northern areas of Europe would constitute refuges for diversity in the future. This is effectively the inverse of what appears to have happened in glacial refugia during the last glacial maximum. From this perspective, the still abundant and large northern populations should be considered as precious as the small almost relict southern ones and perhaps protected. Careful management of the species, coordinated across countries and latitudes, is needed in order to avoid its extinction in Europe.J. L. Horreo was supported by a MINECO Spanish postdoctoral grant (“Juan de la CiervaIncorporación”
(ref. IJCI-2015-23618). This work was funded by the European Union
INTERREG IIIB programme (Atlantic Salmon Arc Project [ASAP], Project No. 040 and
ASAP-2, Project No. 203). This study received additional funding from the Principality of
Asturias Grants for Excellent Research (GRUPIN-2014-093) and the Contract CN-14-076
Type O pure radiation metrics with a cosmological constant
In this paper we complete the integration of the conformally flat pure
radiation spacetimes with a non-zero cosmological constant , and , by considering the case . This is a
further demonstration of the power and suitability of the generalised invariant
formalism (GIF) for spacetimes where only one null direction is picked out by
the Riemann tensor. For these spacetimes, the GIF picks out a second null
direction, (from the second derivative of the Riemann tensor) and once this
spinor has been identified the calculations are transferred to the simpler GHP
formalism, where the tetrad and metric are determined. The whole class of
conformally flat pure radiation spacetimes with a non-zero cosmological
constant (those found in this paper, together with those found earlier for the
case ) have a rich variety of subclasses with zero,
one, two, three, four or five Killing vectors
Probabilistic Guarantees for Safe Deep Reinforcement Learning
Deep reinforcement learning has been successfully applied to many control
tasks, but the application of such agents in safety-critical scenarios has been
limited due to safety concerns. Rigorous testing of these controllers is
challenging, particularly when they operate in probabilistic environments due
to, for example, hardware faults or noisy sensors. We propose MOSAIC, an
algorithm for measuring the safety of deep reinforcement learning agents in
stochastic settings. Our approach is based on the iterative construction of a
formal abstraction of a controller's execution in an environment, and leverages
probabilistic model checking of Markov decision processes to produce
probabilistic guarantees on safe behaviour over a finite time horizon. It
produces bounds on the probability of safe operation of the controller for
different initial configurations and identifies regions where correct behaviour
can be guaranteed. We implement and evaluate our approach on agents trained for
several benchmark control problems
Obtaining a class of Type O pure radiation metrics with a cosmological constant, using invariant operators
Using the generalised invariant formalism we derive a class of conformally
flat spacetimes whose Ricci tensor has a pure radiation and a Ricci scalar
component. The method used is a development of the methods used earlier for
pure radiation spacetimes of Petrov types O and N respectively. In this paper
we demonstrate how to handle, in the generalised invariant formalism,
spacetimes with isotropy freedom and rich Killing vector structure. Once the
spacetimes have been constructed, it is straightforward to deduce their
Karlhede classification: the Karlhede algorithm terminates at the fourth
derivative order, and the spacetimes all have one degree of null isotropy and
three, four or five Killing vectors.Comment: 29 page
Genotipagem de Toxoplasma gondii em galinhas domésticas em uma área rural do Rio Grande do Sul, Brasil
Free-range chickens may ingest oocysts of T. gondii present in the environment and consequently harbor virulent strains of this parasite in different tissues, without any clinical signs. Isolation of T. gondii through bioassays on mice and cats from naturally infected chicken tissues has been described in several countries, demonstrating the importance of free-range chickens in the transmission of this parasite. The aim of this study was the genotypic characterization of T. gondii isolates obtained from naturally infected free-range chickens in a rural area of the state of Rio Grande do Sul, Brazil. Brain and heart tissue from 12 chickens seropositive for T. gondii were processed using peptic digestion technique for parasite isolation. From 12 samples subjected to mouse bioassay, nine isolates were obtained. RFLP-PCR genotypic characterization was performed using 11 genetic markers: SAG1, 5'-3'SAG2, alt.SAG2, SAG3, BTUB, GRA6, c22-8, c29- 2, L358, PK1 and Apico. Genetic characterization of the isolates revealed the presence of five atypical genotypes according to ToxoDB (# 11, # 55, # 64, # 140 and # 163). Our results showed a wide genetic diversity of T. gondii in free-range chickens in this region.Galinhas criadas ao ar livre podem ingerir oocistos de T. gondii presentes no ambiente e, com isso, albergar cepas virulentas desse parasita em diferentes tecidos, sem sinais clínicos. O isolamento de T. gondii por meio de bioensaios em camundongos e gatos, a partir de tecidos de galinhas naturalmente infectadas, tem sido descrito em vários países. Isso demonstra a importância das galinhas caipiras na epidemiologia desse parasita. O objetivo deste trabalho foi caracterizar genotipicamente isolados de T. gondii obtidos de galinhas caipiras naturalmente infectadas em uma área rural do município de Santa Maria, estado do Rio Grande do Sul, Brasil. Fragmentos de cérebro e de coração, de 12 galinhas soropositivas para T. gondii, foram processados pela técnica de digestão péptica para isolamento do parasita. Das 12 amostras submetidas a bioensaio com camundongos, nove isolados foram obtidos. A caracterização genotípica por RFLP-PCR foi realizada utilizando-se 11 marcadores genéticos: SAG1, 5'- 3'SAG2, alt.SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1 e Apico e revelou a presença de cinco genótipos atípicos de acordo com o ToxoDB (# 11, # 55, # 64, # 140 e # 163). Os resultados mostraram uma ampla diversidade genética de T. gondii em galinhas caipiras nessa região.Fil: Camillo, G.. Universidade Federal de Santa Maria; BrasilFil: Machado, M. E. A.. Universidade Federal de Santa Maria; BrasilFil: Cadore, G.C.. Universidade Federal de Santa Maria; BrasilFil: Bräunig, P.. Universidade Federal de Santa Maria; BrasilFil: Venturini, María Cecilia. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Departamento de Epizootiología y Salud Pública. Laboratorio de Inmunoparasitología; ArgentinaFil: Pardini, Lais Luján. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Departamento de Epizootiología y Salud Pública. Laboratorio de Inmunoparasitología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Barros, L.D.. Universidade Estadual de Londrina; BrasilFil: Garcia, J.L.. Universidade Estadual de Londrina; BrasilFil: Sangioni, L.A.. Universidade Federal de Santa Maria; BrasilFil: Vogel, F.S.F.. Universidade Federal de Santa Maria; Brasi
Evaluación de equivalencia semántica de la versión portuguesa (Brasil) de la Online Cognition Scale
This study evaluated the semantic equivalence of the Online Cognition Scale in Brazilian Portuguese. The process included five steps: translation, back-translation, technical review, evaluation of semantic equivalence by trained professionals, and evaluation of the instrument for content understanding by a group of professionals (n = 10) and students (n = 37). The instrument was translated and adapted to Portuguese, showing a high level of verbal comprehension by the target population. The adapted version for use in Brazil resulted in an equivalent instrument from the semantic and content point of view, ready for evaluation of its psychometric qualities in the Brazilian cultural context.El objetivo de este estudio fue llevar a cabo la evaluación de la equivalencia semántica de la Online Cognition Scale en portugués (Brasil). El proceso consistió en cinco etapas: traducción, retrotraducción, revisión técnica y evaluación de la equivalencia semántica de los profesionales; habilitación de instrumentos como la comprensión verbal por una muestra de profesionales (n = 10) y estudiantes (n = 37). El instrumento fue traducido y adaptado al portugués, con un excelente nivel final de comprensión verbal por parte de la población objetivo. La versión adaptada del instrumento para su uso en nuestro contexto, que dio como resultado un instrumento equivalente desde el punto de vista semántico y del contenido, está lista para que comience el estudio de sus propiedades psicométricas en el contexto cultural brasileño.Este estudo teve por objetivo realizar a avaliação da equivalência semântica da Online Cognition Scale para o português (Brasil). O processo consistiu em cinco etapas: tradução; retrotradução; revisão técnica e avaliação da equivalência semântica por profissionais capacitados; avaliação do instrumento quanto à compreensão verbal por uma amostra de profissionais (n = 10) e estudantes (n = 37). O instrumento foi traduzido e adaptado para o português, apresentando, ao final, excelente nível de compreensão verbal pela população alvo. A versão do instrumento adaptada para uso em nosso meio resultou em um instrumento equivalente do ponto de vista da equivalência semântica e de conteúdo, estando pronto para iniciar o estudo de suas qualidades psicométricas no contexto cultural brasileiro.Universidade Federal de São Paulo (UNIFESP)Universidade de PernambucoUNIFESPSciEL
Health-related fitness as a predictor of anxiety levels among school adolescents: an observational cross-sectional study
Background:
There is an inverse association between cardiorespiratory fitness and general anxiety levels in adolescents. Obesity also is associated with a higher risk of anxiety in this population. However, little is known about the association between other health-related fitness elements with anxiety symptoms in this population. The authors explored the relationship between health-related fitness and anxiety symptoms in a large sample of Brazilian youth.
Methods:
This was an observational cross-sectional study with a sample comprised of 257 school adolescents, who were 136 girls (52.9%) and 121 boys (47.1%). The health-related fitness elements were evaluated by FitnessGram® test and anxiety levels by Multidimensional Anxiety Scale for Children - 39. Hierarchical regression analyses were used to determine the association between health-related fitness elements and anxiety symptoms in both sexes.
Results:
In male adolescents, only the cardiorespiratory fitness was significantly associated with anxiety symptoms (F(1, 119) = 6.472; P = 0.012; R2 = 0.052; adjusted R2 = 0.044). In turn, the anxiety symptoms showed an inverse small relationship with cardiorespiratory fitness (r = - 0.227; P < 0.01). However, in female adolescents, no association was found between health-related fitness elements and anxiety symptoms.
Conclusion:
The level of cardiorespiratory fitness may represent a marker of anxiety in male adolescents
Chronic low back pain and its differential diagnoses: a case report
Low back pain is a common problem which accompanies a large part of the population. It is estimated that up to 84% of adults will have low back pain at some point in their lives. Rarely, low back pain may be the first manifestation of a serious illness. This case report presents the clinical history of a 79 year-old male, with multiple comorbities, including a report of a discal hernia treated by surgery approximately 30 years before presentation, with residual low back pain since then. The pain was progressively worsening, associated with loss of muscle strength and paresthesia in the right lower limb, with significant weight loss. During screening, significant anemia and acute kidney injury with associated hypercalcemia were observed. A spine CT scan revealed a large expansile lesion obliterating the medullary canal at T8/T9 segment. A monoclonal spike in protein electrophoresis was found, along with sparse lytic lesions in long bones leading to the diagnosis of multiple myeloma. Therefore, this report highlights the importance of considering different differential diagnoses as a cause of low back pain. The correct determination of the etiology is essential for adequate clinical management and improvement of the patient's quality of life
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