919 research outputs found

    Multiplicative noise: A mechanism leading to nonextensive statistical mechanics

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    A large variety of microscopic or mesoscopic models lead to generic results that accommodate naturally within Boltzmann-Gibbs statistical mechanics (based on S1kdup(u)lnp(u)S_1\equiv -k \int du p(u) \ln p(u)). Similarly, other classes of models point toward nonextensive statistical mechanics (based on Sqk[1du[p(u)]q]/[q1]S_q \equiv k [1-\int du [p(u)]^q]/[q-1], where the value of the entropic index qq\in\Re depends on the specific model). We show here a family of models, with multiplicative noise, which belongs to the nonextensive class. More specifically, we consider Langevin equations of the type u˙=f(u)+g(u)ξ(t)+η(t)\dot{u}=f(u)+g(u)\xi(t)+\eta(t), where ξ(t)\xi(t) and η(t)\eta(t) are independent zero-mean Gaussian white noises with respective amplitudes MM and AA. This leads to the Fokker-Planck equation tP(u,t)=u[f(u)P(u,t)]+Mu{g(u)u[g(u)P(u,t)]}+AuuP(u,t)\partial_t P(u,t) = -\partial_u[f(u) P(u,t)] + M\partial_u\{g(u)\partial_u[g(u)P(u,t)]\} + A\partial_{uu}P(u,t). Whenever the deterministic drift is proportional to the noise induced one, i.e., f(u)=τg(u)g(u)f(u) =-\tau g(u) g'(u), the stationary solution is shown to be P(u,){1(1q)β[g(u)]2}11qP(u, \infty) \propto \bigl\{1-(1-q) \beta [g(u)]^2 \bigr\}^{\frac{1}{1-q}} (with qτ+3Mτ+Mq \equiv \frac{\tau + 3M}{\tau+M} and β=τ+M2A\beta=\frac{\tau+M}{2A}). This distribution is precisely the one optimizing SqS_q with the constraint q{du[g(u)]2[P(u)]q}/{du[P(u)]q}=_q \equiv \{\int du [g(u)]^2[P(u)]^q \}/ \{\int du [P(u)]^q \}= constant. We also introduce and discuss various characterizations of the width of the distributions.Comment: 3 PS figure

    Molecular and genetic mechanism of non-syndromic congenital cataracts. Mutation screening in Spanish families

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    Our purpose was to identify mutations responsible for non-syndromic congenital cataracts through the implementation of next-generation sequencing (NGS) in our center. A sample of peripheral blood was obtained from probands and willing family members and genomic DNA was extracted from leukocytes. DNA was analyzed implementing a panel (OFTv2.1) including 39 known congenital cataracts disease genes. 62 probands from 51 families were recruited. Pathogenic or likely pathogenic variants were identified in 32 patients and 25 families; in 16 families (64%) these were de novo mutations. The mutation detection rate was 49%. Almost all reported mutations were autosomal dominant. Mutations in crystallin genes were found in 30% of the probands. Mutations in membrane proteins were detected in seven families (two in GJA3 and five in GJA8). Mutations in LIM2 and MIP were each found in three families. Other mutations detected affected EPHA2, PAX6, HSF4 and PITX3. Variants classified as of unknown significance were found in 5 families (9.8%), affecting CRYBB3, LIM2, EPHA2, ABCB6 and TDRD7. Mutations lead to different cataract phenotypes within the same familyThis research was funded by ONCE grant number 2020/0197782 and by FIS grant number PI18-1234-ISCII

    Comparative Distribution of Relaxin-3 Inputs and Calcium-Binding Protein-Positive Neurons in Rat Amygdala

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    The neural circuits involved in mediating complex behaviors are being rapidly elucidated using various newly developed and powerful anatomical and molecular techniques, providing insights into the neural basis for anxiety disorders, depression, addiction, and dysfunctional social behaviors. Many of these behaviors and associated physiological processes involve the activation of the amygdala in conjunction with cortical and hippocampal circuits. Ascending subcortical projections provide modulatory inputs to the extended amygdala and its related nodes (or ‘hubs’) within these key circuits. One such input arises from the nucleus incertus (NI) in the tegmentum, which sends amino acid- and peptide-containing projections throughout the forebrain. Notably, a distinct population of GABAergic NI neurons expresses the highly-conserved neuropeptide, relaxin-3, and relaxin-3 signaling has been implicated in the modulation of reward/motivation and anxiety- and depressive-like behaviors in rodents via actions within the extended amygdala. Thus, a detailed description of the relaxin-3 innervation of the extended amygdala would provide an anatomical framework for an improved understanding of NI and relaxin-3 modulation of these and other specific amygdala-related functions. Therefore, in this study, we examined the distribution of NI projections and relaxin-3-positive elements (axons/fibers/terminals) within the amygdala, relative to the distribution of neurons expressing the calcium-binding proteins, parvalbumin, calretinin and/or calbindin. Anterograde tracer injections into the NI revealed a topographic distribution of NI efferents within the amygdala that was near identical to the distribution of relaxin-3-immunoreactive fibers. Highest densities of anterogradely-labeled elements and relaxin-3-immunoreactive fibers were observed in the medial nucleus of the amygdala, medial divisions of the bed nucleus of the stria terminalis (BST) and in the endopiriform nucleus. In contrast, sparse anterogradely-labeled and relaxin-3-immunoreactive fibers were observed in other amygdala nuclei, including the lateral, central and basal nuclei and the nucleus accumbens lacked any innervation. Using synaptophysin as a synaptic marker, we identified relaxin-3 positive synaptic terminals in the medial amygdala, BST and endopiriform nucleus of amygdala. Our findings demonstrate the existence of topographic NI and relaxin-3-containing projections to specific nuclei of the extended amygdala, consistent with a likely role for this putative integrative arousal system in the regulation of amygdala-dependent social and emotional behaviors

    Prevalence of hepatitis A in the capitals of the States of North, Southeast and South regions of Brazil: decrease in prevalence and some consequences

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    Hepatitis A virus (HAV) infection has been considered one of the leading causes of acute hepatitis. The aim of the present study was to estimate the prevalence of HAV among children and adolescents in a population-based study in the capitals of the States of the North, Southeast and South of Brazil and identify predictive factors for the infection. A multi-stage sampling was used to select subjects aged between 5-9 and 10-19 years. Individual and household levels aside from the level of variables in the areas were collected. The outcome was the total IgG antibodies to HAV levels detected using a commercial Enzyme Immuno Assay (EIA). The associations between HAV and the independent variables were assessed using the odds ratio. A multilevel analysis was performed by GLLAMM using the Stata software. The prevalence of HAV infection in the 5-9 and 10-19 age groups was 28.7% and 67.5%, respectively for the North, 20.6% and 37.7%, for the Southeast and 18.9% and 34.5% for the South Region. The prevalence of HAV increased according to age in all sites. Variables related to education at the individual level (North and South), family and area level (South and Southeast) and family income level (Southeast and South) were independently associated with HAV infection. This emphasizes the need for individualized strategies to prevent the infection

    Exercícios resistidos e uso de decanoato de nandrolona e a alteração do epidídimo de ratos adultos e idosos / Resistence training and the use of nandrolone decanoate change epididymis in adult and aged rats

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    Introdução: O sistema genital masculino é alvo de estudos por ser sensível a mudanças na concentração de androgênios, e esses são alterados em algumas situações como: exercício, uso de anabolizantes (EAAs) e o envelhecimento. Um dos órgãos androgênio-dependentes é o epidídimo. Objetivo: Verificar se o tratamento com EAAs associado ou não a exercício físico, em ratos Sprague-Dawley altera a morfologia e morfometria do Epidídimo em ratos adultos e seus efeitos crônicos em idosos. Métodos: Foram analisados epidídimos de 56 ratos Sprague-Dawley, virgens, com 13 semanas de vida ao início do experimento, separados em oito grupos com sete animais cada: GC - adultos e sedentários; GCi - idosos e sedentários; GN - adultos, sedentários, tratados com EAA; GNi - idosos, sedentários, tratados com EAA; GE - adultos tratados com exercício; GEi - idosostratados com exercício; GNE - adultos, exercício e tratamento com EAA; GNEi - idosos, exercício e tratamento com EAA. Os animais adultos foram eutanasiados com 150 dias, os idosos, 330 dias. O treinamento realizado foi através de saltos na água, com sobrecarga. A administração de EAAs ocorreu pela aplicação intramuscular de Decanoato de Nandrolona (10 mg/kg/semana). Amostras epididimárias passaram pela rotina histológica de hematoxilina e eosina para análise morfológica e morfométrica. Resultados: O GE apresentou diâmetro de ducto menor quando comparados ao controle, já o GN e GNE, tiveram diâmetro de ducto e a altura epitelial aumentados comparando-os com o controle, sendo estas alterações principalmente nos segmentos mais iniciais do epidídimo. Já os grupos idosos tenderam a retornar a normalidade, a não ser na cauda, do GNEi. Também foram encontrados indícios inflamatórios no tecido dos grupos experimentais (GN, GE, GNE e GCi) e ainda, debris de células da linhagem germinativa no interior do lúmen de GN e GNEi. Conclusão: Tanto o tratamento na fase adulta com exercício, quanto à utilização de EAAs altera parâmetros morfométricos e morfológicos do epidídimo, e  seu efeito crônico pode ser diminuído com a idade

    Situação nutricional e alimentar de pré-escolares no semi-árido da Bahia (Brasil): I.Avaliação antropométrica

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    A survey of 754 preschool children was undertaken in the urban areas of seven small towns of the semi-arid region of Bahia, Northeast Brazil. The study set out to determine the prevalence of weight and height deficits, as well as to correlate them with variables such as age, family income, mother's schooling and food consumption. A prevalence of 22.9% of Height for Age (HA) below -2.0 SD was found (stunting) and prevalence of 19.1% and 3.6% were determined, respectively for Weight for Age (WA) and Weight for Height (WH) below -2.0 SD (wasting). Regarding food consumption, only 6.8% of the children received a diet with an adequate energy supply for their age group in the previous day. There was a close association between inadequate HA and WA and family income per capita (p=0.001 and p=0.000, respectively). Children from families with income ; 1/2 minimum wage per capita stratum. The children included in this study showed prevalences of inadequate WH and WA significantly higher than those found in a national survey conducted in the same period (p=0.047 and p=0.000 respectively). This fact is surprising since in the last decade important reductions in child malnutrition and mortality were reported in the country as a whole; this may indicate that children from this region probably were not benefited in the same way as the rest of the Brazilian child population.Foram estudados 754 pré-escolares de áreas urbanas de sete municípios do semi-árido da Bahia, Brasil. Os objetivos foram determinar a prevalência de déficit ponderal e estatural, indicativos de desnutrição atual e/ou pregressa e sua associação com a idade, sexo, renda em salário-mínimo (SM), escolaridade materna e adequação do consumo alimentar. Encontrou-se 22,9% de crianças com altura/idade abaixo de -2,0 DP (desnutrição pregressa), 19,1% com peso/idade e 3,6% com peso/altura abaixo de -2,0 DP (desnutrição atual). Em relação ao inquérito dietético somente 6,8% das crianças haviam consumido no dia anterior uma dieta que suprisse os requerimentos energéticos para sua faixa etária. Houve forte associação entre os indicadores A/l e P/l inadequados com renda familiar per capita (p=0,001 e p=0,000, respectivamente); crianças de famílias com renda per capita ;1/2 SM. Em relação ao P/A como também P/l, os pré-escolares estudados no semi-árido apresentaram prevalências significativamente superiores às encontradas por pesquisa nacional realizada na mesma época (p=0,047 e p=0,000, respectivamente). Esses achados surpreendem, já que nas últimas décadas tem sido demonstrada no Brasil uma melhoria signifivativa na desnutrição e mortalidade infantil e parecem indicar que as crianças do semi-árido não lograram ainda alcançar os mesmos benefícios que o restante da população infantil brasileira

    The timing of the deglaciation in the Atlantic Iberian mountains: Insights from the stratigraphic analysis of a lake sequence in Serra da Estrela (Portugal)

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    Understanding the environmental response to the last glacial termination in regions located in transitional climate zones such as the Atlantic Iberian mountains is crucial to estimate potential changes in regions affected by current glacial melting. We present an 8.5 m-long, solid last deglaciation and Holocene chronostratigraphic record including detailed sediment analysis from Lake Peixao, a pro-glacial lake in the Serra da Estrela (Central Portugal). The age-depth model relies on a Bayesian approach that includes 16 AMS C-14 dates and Pb-210-(CS)-C-137 measurements, robustly dating the lake formation at 14.7 +/- 0.32 cal. ka BP. This chronological reconstruction shows an average sedimentation rate of ca. 0.07 cm yr(-1) (15 yr cm(-1)), enabling proxy analyses at decadal timescales. The sediment sequence is composed of five lithological units: (U1) coarse and unsorted fluvioglacial lacustrine deposits; (U2) massive fluvioglacial lacustrine deposits (863-790 cm below surface [bsf]; 14.7 +/- 0.32-13.8 +/- 0.12 cal. ka BP); (U3) water current fluvioglacial lacustrine deposits (790-766 cm bsf; 13.8 +/- 0.12-12.9 +/- 0.29 cal. ka BP); (U4) laminated/banded lacustrine deposits characterized by terrigenous deposits from ice-covered lake periods and episodic events of ice and snow melting (766-752 cm bsf; 12.9 +/- 0.29-11.7 +/- 0.15 cal. ka BP); and (U5) massive muddy lacustrine deposits (752-0 cm bsf; 11.7 +/- 0.15 cal. ka BP-present). The occurrence of U2 to U4 deposits defines the transition from glacial cold (U1) to net warm postglacial conditions (U5). These climate transitions are marked by changes in sediments and the presence of very low sedimentation rate periods, possibly related to the Intra-Allerod Cold Period and the coldest phase of the Younger Dryas. Our results support the previously proposed timing of the retreat of the Serra da Estrela glaciers ca. 13.8 +/- 0.12 cal. ka BP. The robust chronology of Lake Peixao highlights the potential of Iberian pro-glacial lakes for dating deglaciation processes and will lead to unprecedented decadal-to-centennial timescale palaeoclimate reconstructions in this region since the last glacial-interglacial transition.info:eu-repo/semantics/publishedVersio

    The timing of the deglaciation in the Atlantic Iberian mountains: Insights from the stratigraphic analysis of a lake sequence in Serra da Estrela (Portugal)

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    Understanding the environmental response to the last glacial termination in regions located in transitional climate zones such as the Atlantic Iberian mountains is crucial to estimate potential changes in regions affected by current glacial melting. We present an 8.5 m-long, solid last deglaciation and Holocene chronostratigraphic record including detailed sediment analysis from Lake Peix˜ao, a pro-glacial lake in the Serra da Estrela (Central Portugal). The age–depth model relies on a Bayesian approach that includes 16 AMS 14C dates and 210Pb–137CS measurements, robustly dating the lake formation at 14.7 ± 0.32 cal. ka BP. This chronological reconstruction shows an average sedimentation rate of ca. 0.07 cm yr 1 (15 yr cm 1), enabling proxy analyses at decadal timescales. The sediment sequence is composed of five lithological units: (U1) coarse and unsorted fluvioglacial lacustrine deposits; (U2) massive fluvioglacial lacustrine deposits (863–790 cm below surface [bsf]; 14.7 ± 0.32–13.8 ± 0.12 cal. ka BP); (U3) water current fluvioglacial lacustrine deposits (790–766 cm bsf; 13.8 ± 0.12–12.9 ± 0.29 cal. ka BP); (U4) laminated/banded lacustrine deposits characterized by terrigenous deposits from ice-covered lake periods and episodic events of ice and snow melting (766–752 cm bsf; 12.9 ± 0.29–11.7 ± 0.15 cal. ka BP); and (U5) massive muddy lacustrine deposits (752–0 cm bsf; 11.7 ± 0.15 cal. ka BP–present). The occurrence of U2 to U4 deposits defines the transition from glacial cold (U1) to net warm postglacial conditions (U5). These climate transitions are marked by changes in sediments and the presence of very low sedimentation rate periods, possibly related to the Intra-Allerød Cold Period and the coldest phase of the Younger Dryas. Our results support the previously proposed timing of the retreat of the Serra da Estrela glaciers ca. 13.8 ± 0.12 cal. ka BP. The robust chronology of Lake Peix˜ao highlights the potential of Iberian pro-glacial lakes for dating deglaciation processes and will lead to unprecedented decadal-to-centennial timescale palaeoclimate reconstructions in this region since the last glacial–interglacial transition.info:eu-repo/semantics/publishedVersio
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