Impact of the pulvinar on the ventral pathway of the cat visual cortex

Signals from the retina are relayed to the lateral geniculate nucleus from which they are sent to the primary visual cortex. At the cortical level, the information is transferred across several visual areas in which the complexity of the processing increases progressively. Anatomical and functional evidence demonstrate the existence of two main pathways in visual cortex processing distinct features of the visual information: the dorsal and ventral streams. Cortical areas composing the dorsal stream are implicated mostly in motion processing while those comprising the ventral stream are involved in the processing of form and colour. This classic view of the cortical functional organization is challenged by the existence of reciprocal connections of visual cortical areas with the thalamic nucleus named pulvinar. These connections allow the creation of a trans-thalamic pathway that parallels the cortico-cortical communications across the visual hierarchy. The main goal of the present thesis is twofold: first, to obtain a better comprehension of the processing of light increments and decrements in an area of the cat ventral stream (area 21a); second, to characterize the nature of the thalamo-cortical inputs from the cat lateral posterior nucleus (LP) to area 21a. In study #1, we investigated the spatiotemporal response profile of neurons from area 21a to light increments (brights) and decrements (darks) using a reverse correlation analysis of a sparse noise stimulus. Our findings showed that 21a neurons exhibited stronger responses to darks with receptive fields exhibiting larger dark subfields. However, no differences were found between the temporal dynamics of brights and darks. In comparison with the primary visual cortex, the dark preference in area 21a was found to be strongly enhanced, supporting the notion that the asymmetries between brights and darks are transmitted and amplified along the ventral stream. In study #2, we investigated the impact of the reversible pharmacological inactivation of the LP nucleus on the contrast response function (CRF) of neurons from area 21a and the primary visual cortex (area 17). The thalamic inactivation yielded distinct effects on both cortical areas. While in area 17 the LP inactivation caused a slight decrease in the response gain, in area 21a a strong increase was observed. Thus, our findings suggest that the LP exerts a modulatory influence on the cortical processing along the ventral stream with stronger impact on higher order extrastriate areas. Taken together, our findings allowed a better comprehension of the functional properties of the cat ventral stream and contributed to the current knowledge on the role of the pulvinar on the cortico-thalamo-cortical processing of visual information.Les signaux provenant de la rétine sont relayés dans le corps géniculé latéral où ils sont envoyés au cortex visuel primaire. L’information passe ensuite à travers plusieurs aires visuelles où la complexité du traitement augmente progressivement. Des données tant anatomiques que fonctionnelles ont démontré l’existence de deux voies principales qui traitent différentes propriétés de l’information visuelle : les voies dorsale et ventrale. Les aires corticales composant la voie dorsale sont impliquées principalement dans le traitement du mouvement tandis que les aires de la voie ventrale sont impliquées dans le traitement de la forme et de la couleur. Cette vision classique de l’organisation fonctionnelle du cortex est toutefois remise en question par l’existence de connections réciproques entre les aires corticales visuelles et le pulvinar, un noyau thalamique. En effet, ces connections permettent la création d’une voie trans-thalamique parallèle aux connections cortico-corticales à travers la hiérarchie visuelle. Le but principal de la présente thèse consiste en deux volets : le premier est d’obtenir une meilleure compréhension du traitement des incréments et décréments de la lumière dans une aire de la voie ventrale du chat (aire 21a); le second est de caractériser la nature des inputs thalamo-corticaux du noyau latéral postérieur (LP) à l’aire 21a chez le chat. Dans l’étude #1, nous avons investigué le profil spatiotemporel des réponses des neurones de l’aire 21a aux incréments (blancs) et décréments (noirs) de lumière en utilisant l’analyse de corrélation inverse d’un stimulus de bruit épars. Les neurones de l’aire 21a ont répondu plus fortement aux stimuli noirs, en montrant des champs récepteurs avec des sous-champs noirs plus larges. Cependant, aucune différence n’a été trouvée en ce qui concerne les dynamiques temporelles des réponses aux blancs et aux noirs. En comparaison avec le cortex visuel primaire, la préférence aux stimuli noirs dans l’aire 21a s’est avérée fortement augmentée. Ces données indiquent que les asymétries entre les réponses aux blancs et aux noirs sont transmises et amplifiées à travers la voie ventrale. Dans l’étude #2, nous avons investigué l’impact de l’inactivation pharmacologique réversible du noyau LP sur la fonction de réponse au contraste (CRF) des neurones de l’aire 21a et du cortex visuel primaire (aire 17). L’inactivation a eu différents effets dans les deux aires corticales. Alors que, dans l’aire 17, l’inactivation du LP a causé une légère réduction du gain de la réponse, une forte augmentation a été observée dans l’aire 21a. Ainsi, nos résultats suggèrent que le LP exerce une influence modulatrice dans le traitement cortical à travers la voie ventrale avec un impact plus important dans des aires extrastriées de plus haut niveau. Nos résultats ont permis d’avoir une meilleure compréhension des propriétés fonctionnelles de la voie ventrale du chat et de contribuer à enrichir les connaissances actuelles sur le rôle du pulvinar dans le traitement cortico-thalamo-cortical de l’information visuelle

The Impact of Sex and Performance Level on Pacing Behavior in a 24-h Ultramarathon

Purpose: We analyzed the impact of sex, performance level and substantial speed reductions (SSR) on pacing in the VI Rio 24-h Marines Ultramarathon. This will provide insights into the importance of minimizing speed variations in relation to optimal pacing in endurance events. Methods: Runners (30 males and 21 females), classified as high- (HP) and low-performance (LP) ran the race while having their time recorded every 400 m. The pacing was analyzed as the first 10% (initial epoch), the following 80% (intermediate epoch) and the last 10% of the race (final epoch). The time percentage spent at speeds 8.0 km·h−1 (running speed) was calculated. Results: Runners showed a reverse J-shaped pacing (P < 0.001) regardless of sex and performance level, although male (P < 0.004) and HP runners (P < 0.001) have preserved a higher mean speed throughout the race. Male and HP runners spent more time at running speed (P < 0.001) and less time at SSR (P < 0.001) than female and LP runners. Total distance was inversely correlated with the number of SSR and speed CV in male (r = −0.47 and r = −0.64, respectively) and female (r = −0.61 and r = −0.47, respectively). Conclusion: Male, HP runners showed less SSR, conserving a higher mean speed with less variation throughout the race. Results suggest that conservative pacing strategies, with lower speeds in the beginning and higher speeds toward the end, may be the most adequate for different endurance running disciplines. Results also show different competition dynamics between men and women, which warrants further exploration in ultramarathons as well as other IAAF events

Numerical Study of Turbulent Flows and Heat Transfer in Coupled Industrial-Scale Tundish of a Continuous Casting Material in Steel Production

This chapter describes the numerical simulations of a coupled industrial scale of the tundish and continuous casting process. The governing equations are presented, and the numerical procedure is discussed in a common framework. The coupled solutions are presented for the transient turbulent flows within the tundish, solidifying zone and extracting regions with the coupling phenomena of heat and mass transfer. The tundish region flow and refractory are calculated using the inlet and outlet boundary conditions in order to estimate the filling phenomena. The transitions and cooling zones for the thin slab continuous casting process are designed to account for the control of the solidified skin in order to avoid breakout. We compared the numerical predictions of the temperatures with industrial monitoring data for a reference case in order to verify the consistence of the model predictions. A parallel version of the numerical code is proposed aiming to improve the computation time keeping numerical accuracy

Concentrations of indolebutyric acid on air-layering of guava cv. Paluma

Nowadays, the predominant technique for the commercial propagation of guava seedlings is through cuttings, using herbaceous cuttings that need a specialized infrastructure with intermittent misting, clean water, exhausters, water filters, and fans. As an alternative to plant propagation by cuttings, this study aimed to evaluate the influence of concentrations of indolebutyric acid (IBA) on the rooting of branches of the guava cv. Paluma by air-layering. The experimental design was in randomized blocks, with four replications and 10 air layers per plot. The treatments consisted of six concentrations of IBA powder mixed with industrial talcum: 0, 1,000, 2,000, 3,000, 4,000, and 5,000 mg.kg-1. Four adult guava parents that were in the off-season period were used. For the preparation of the air layers, the stems were girdled with a 4.0 cm width, using a steel blade, by removing the bark until exposing the cambium region, followed by IBA application and wrapping of the branches with a plastic bag containing moist organic substrate. The following variables were evaluated 120 days after air-layering: percentage of rooted and callused air layers, longest root length, and root dry matter. The analysis of variance indicated no significant differences between the IBA concentrations for all variables, but the rooting percentages were high (68.6 to 92.2%) regardless of the application of the exogenous auxin.Nowadays, the predominant technique for the commercial propagation of guava seedlings is through cuttings, using herbaceous cuttings that need a specialized infrastructure with intermittent misting, clean water, exhausters, water filters, and fans. As an alternative to plant propagation by cuttings, this study aimed to evaluate the influence of concentrations of indolebutyric acid (IBA) on the rooting of branches of the guava cv. Paluma by air-layering. The experimental design was in randomized blocks, with four replications and 10 air layers per plot. The treatments consisted of six concentrations of IBA powder mixed with industrial talcum: 0, 1,000, 2,000, 3,000, 4,000, and 5,000 mg.kg-1. Four adult guava parents that were in the off-season period were used. For the preparation of the air layers, the stems were girdled with a 4.0 cm width, using a steel blade, by removing the bark until exposing the cambium region, followed by IBA application and wrapping of the branches with a plastic bag containing moist organic substrate. The following variables were evaluated 120 days after air-layering: percentage of rooted and callused air layers, longest root length, and root dry matter. The analysis of variance indicated no significant differences between the IBA concentrations for all variables, but the rooting percentages were high (68.6 to 92.2%) regardless of the application of the exogenous auxin

Composição florística da regeneração natural de área de cerrado sensu stricto e sub-bosque de clones de eucalipto

O Cerrado é o segundo bioma mais importante do Brasil, conhecido principalmente devido a sua biodiversidade, dentre os estados brasileiros o Tocantins se destaca por possuir a maior quantidade de remanescentes deste bioma. O objetivo desse trabalho foi avaliar a composição florística da regeneração natural de uma área de cerrado sensu stricto (c.s.s) e o sub-bosque de dois povoamentos de Eucalyptus urocam (E. uc) e E. urograndis (E. ug), além de comparar a riqueza e diversidade das espécies e a similaridade entre as áreas. Esse estudo foi conduzido na zona rural do município de Aliança do Tocantins (TO), nos limites da propriedade privada Nossa Senhora Aparecida. Foram instaladas aleatoriamente três parcelas amostrais de 20 x 50 m em três áreas experimentais, perfazendo um total de 3000 m² ou 0,3 ha em cada área experimental. Foram amostrados todos os indivíduos com altura ≥ a 1 m e ≤ a 3 m e circunferência na altura do solo ≥ a 10 cm. Foram identificados nas três áreas experimentais um total de 74 espécies, 31 famílias e 61 gêneros. Na área (c.s.s) foram amostradas 56 espécies, 24 famílias e 49 gêneros, na área (E. uc) foram encontradas 20 espécies, 15 famílias e 19 gêneros, e na área (E. ug) 27 espécies, 18 famílias e 24 gêneros. O índice de diversidade de Shannon (H’) encontrado foi 3,10; 2,87 e 2,36 e equabilidade de Pielou (J’) foi 0,77; 0,96 e 0,72, respectivamente, para as três áreas. A maior similaridade florística encontrada foi entre as áreas de E. uc e E. ug (46%) e a menor entre as áreas (c.s.s) e E. uc (21%)

Incorporating costs, thresholds and spatial extents for selecting stream bioindicators in an ecotone between two Brazilian biodiversity hotspots

Biomonitoring is critical for characterizing and monitoring status, spatial patterns, and long-term trends in the ecological condition of freshwater ecosystems. The selection of cost-effective bioindicators is a critical step in establishing such monitoring programs. Key indicator considerations are a reliable response to anthropogenic disturbances, a high benefit-cost-ratio and sensitivity at multiple spatial extents. We evaluated non-linear responses of Ephemeroptera, Plecoptera and Trichoptera (EPT) and fish to the effects of native vegetation loss within buffers of 100 m and 1000 m and assessed the sampling and processing costs involved for each assemblage. We sampled 37 neotropical stream sites in the Formoso River network, a karstic region of the Bodoquena Plateau, midwest Brazil, lying in the ecotone between the Cerrado and Atlantic Forest biological hotspots. We used TITAN (threshold indicator taxa analysis) to identify six indicator taxa, four EPT genera and two fish species. The four EPT genera had low negative thresholds to native vegetation loss, whereas the two fish species had positive thresholds. Thresholds were lower for the 100 m buffers than the 1000 m buffers for EPT. The most sensitive taxon (Macronema, Trichoptera) had a threshold of 0% native vegetation loss in the 100 m buffers and nearly 40% in the 1000 m buffers. For taxa richness, we found no non-linear response to the effects of native vegetation loss for buffer extent nor assemblage. The total cost for EPT biomonitoring was US$3,616; whereas for fish, the total was US$ 1,901. Although fish were less expensive than EPT, they did not respond negatively to native vegetation loss and their positive threshold started at 48%, a level of vegetation loss that was highly disruptive of EPT. Therefore, we do not recommend using fish to monitor the effects of native vegetation loss on headwater streams in the Bodoquena Plateau. Although EPT monitoring costs 52% more than fish assemblage monitoring, it detected earlier impacts of the effects of native vegetation loss on stream biota, especially in the 100 m buffer. Therefore, EPT are more cost-effective early warning indicators for monitoring the effects of native vegetation loss in Bodoquena Plateau headwaters

Profilaxia primária e secundária de fraturas osteoporóticas: avaliação de uma coorte prospectiva

ResumoObjetivoMedir a prevalência da profilaxia medicamentosa primária de fraturas por osteoporose em pacientes internados em um hospital terciário de ensino, em uma cidade de médio porte, admitidos com fraturas osteoporóticas. Além disso, identificar a incidência de prescrição de profilaxia medicamentosa secundária após o evento da primeira fratura. Paralelamente, medimos a prevalência de fatores de risco para fratura por osteoporose descritos na literatura.MétodoEstudo longitudinal de uma coorte prospectiva de pacientes admitidos em hospital terciário de ensino de outubro de 2015 a janeiro 2016. Foram incluídos pacientes com fraturas de baixa energia ou por fragilidade, independentemente do gênero ou etnia, acima de 50 anos. Todos os pacientes que não apresentavam essas características foram excluídos. O seguimento foi de quatro meses. Foram aplicados questionários seriados na admissão, no retorno com quatro a oito semanas e com 16 semanas.ResultadoSomente um paciente referiu ter recebido tratamento com drogas específicas para a doença antes da internação hospitalar, o que revela uma prevalência de quimioprofilaxia primária de apenas 2,27%. Nenhum paciente recebeu prescrição para tratamento da osteoporose após a fratura. A prevalência dos fatores de risco de fratura se assemelha àquela encontrada na literatura.ConclusãoA frequência de quimioprofilaxia primária e secundária da osteoporose em pacientes admitidos com fraturas por fragilidade é baixa em nosso meio, assim como a indicação precoce de tratamento medicamentoso após a primeira fratura. A prevalência dos fatores de risco de fratura por fragilidade é semelhante àquela citada na literatura.AbstractObjectiveTo measure the prevalence of primary drug prevention of osteoporosis fracture in patients admitted to a tertiary teaching hospital, in a medium‐sized city, admitted with osteoporotic fractures. Moreover, to identify the incidence of prescribing secondary prophylaxis after the first fracture event. At the same time, the prevalence of risk factors for such fractures as described in the literature was measured.MethodsThis longitudinal prospective study was based on a cohort of patients admitted in a tertiary teaching hospital from October 2015 to January 2016. Patients with low energy or fragility fractures, regardless of gender or race, over the age of 50 years, were included in the study. All patients who did not have these characteristics were excluded. The follow‐up lasted four months. Serial questionnaires were applied at admission and in the follow‐up consultations at four to eight weeks and at 16 weeks.ResultsOnly one patient reported receiving treatment with specific drugs for the disease before the hospital admission, resulting in a prevalence of primary chemoprophylaxis of only 2.27%. No patient was prescribed medication for the treatment of osteoporosis after the fracture. The prevalence of risk factors was similar to those found in the literature review.ConclusionIn the present study, the frequency of primary and secondary osteoporosis chemoprophylaxis in patients who were admitted with fragility fractures was low, revealing the need to develop specific strategies to address this issue. The prevalence of fragility fracture risk factors are similar to those reported in the literature

The Impact of Mobile Phone Use on Adolescent Health

With the increasing rise of smartphones among adolescents, the question arose about the impact of the use of mobile phones among this audience, seeking to assess the harms caused by their excessive use. The present work was elaborated through bibliographical research in articles, books and websites, in a non-systematic way through qualitative and quantitative research, analyzing printed questionnaire. Regarding the results related to the problems caused by the use of smartphones, such as lack of attention, indisposition, poor school performance, little interaction in the classes kept an average of 22.5% difference for those who felt affected, about the posture we have a relatively few. high, however, is still less than half of respondents, but only 33.75% of people who do not worry about posture when using the phone showing, therefore, that young people, focus of our research, has a good ergonomic behavior , both when using the smartphone and watching classes, picking up objects on the floor, and sitting in the chair

Densidade parasitária e potencial ornitocórico de aves silvestres: resultados preliminares de um projeto de pesquisa e extensão realizado em área de reflorestamento no Campus IFRJ, Pinheiral, Rio de Janeiro, Brasil

This publication aims to disseminate to the scientific community and society in general, the project of the same title of this publication that is under development by the collaboration of the Instituto Federal de Educação, Ciência e Tecnologia do Rio de Janeiro (IFRJ) and the Universidade Federal Rural do Rio de aneiro (UFRRJ). Briefly, this project aims to quantify and identify parasites of the body surface (ectoparasites) and intestinal parasites (enteroparasites) of wild birds, which should be related to their biological and ecological conditions, and to evaluate the dispersal seed process performed by birds (ornithocoria), the viability and development of these seeds and thus establish the degree of importance of ornithocoria in reforestation at the IFRJ campus of Pinheiral, RJ. The project includes the integration of five doctoral professors, a laboratory technician doctor, as well as a postdoctoral student, four doctoral students, one master student, two undergraduate students and four technical high school students. To date, six expeditions have been made in the reforestation area of the Espaço Ecológico Educativo (EEcoE) of the IFRJ campus in Pinheiral, RJ, where a total of 196 wild birds have been captured, evaluated, ringed and recorded at the Centro Nacional de Pesquisa e Conservação de Aves Silvestres (CEMAVE), of which 29 were recaptured for revaluations. Four articles were published on the themes of parasitology and ornithochory in wild birds. Two practical short courses in the area of study were taught in September 2018 and February 2019 to IFRJ students, but open to the scientific community and society at large. Currently the project is not expected to end, since there are plenty of unpublished and relevant results in both the area of parasitology and ornithochory of wild birds.A presente publicação tem por objetivo divulgar, à comunidade científica e à sociedade em geral, o projeto de mesmo título desta publicação que está em desenvolvimento em colaboração dos Instituto Federal de Educação, Ciência e Tecnologia do Rio de Janeiro (IFRJ) e Universidade Federal Rural do Rio de Janeiro (UFRRJ). Resumidamente, este projeto objetiva quantificar e identificar parasitas da superfície corporal (ectoparasitas) e parasitas intestinais (enteroparasitas) de aves silvestres, os quais devem estar relacionados às suas condições biológicas e ecológicas, além de avaliar o processo de dispersão de sementes desempenhado pelas aves (ornitocoria), a viabilidade e desenvolvimento destas sementes e, desta forma, estabelecer o grau de importância da ornitocoria no reflorestamento no campus IFRJ de Pinheiral, RJ. O projeto conta com a integração de cinco professores doutores, uma doutora técnica de laboratório, além de um pós-doutorando, quatro doutorandos, um mestrando, dois estudantes de iniciação científica e quatro estudantes de ensino médio-técnico. Até o presente momento, foram realizadas seis expedições na área em reflorestamento do Espaço Ecológico Educativo (EEcoE) do campus IFRJ em Pinheiral, RJ, onde o total de 196 aves silvestres foram capturadas, avaliadas, anilhadas e registradas no Centro Nacional de Pesquisa e Conservação de Aves Silvestres (CEMAVE), das quais 29 foram recapturadas para reavaliações. Quatro artigos foram publicados nos temas de parasitologia e ornitocoria em aves silvestres. Dois minicursos práticos, na área de estudo, foram ministrados em setembro de 2018 e fevereiro de 2019 para alunos do IFRJ, porém aberto para a comunidade científica e sociedade em geral. Atualmente o projeto não tem previsão para término, desde que há abundância de resultados inéditos e relevantes tanto na área de parasitologia, quanto ornitocoria em aves silvestres

Landsat sub-pixel land cover dynamics in the Brazilian Amazon

The Brazilian Amazon land cover changes rapidly due to anthropogenic and climate drivers. Deforestation and forest disturbances associated with logging and fires, combined with extreme droughts, warmer air, and surface temperatures, have led to high tree mortality and harmful net carbon emissions in this region. Regional attempts to characterize land cover dynamics in this region focused on one or two anthropogenic drivers (i.e., deforestation and forest degradation). Land cover studies have also used a limited temporal scale (i.e., 10–15 years), focusing mainly on global and country-scale forest change. In this study, we propose a novel approach to characterize and measure land cover dynamics in the Amazon biome. First, we defined 10 fundamental land cover classes: forest, flooded forest, shrubland, natural grassland, pastureland, cropland, outcrop, bare and impervious, wetland, and water. Second, we mapped the land cover based on the compositional abundance of Landsat sub-pixel information that makes up these land cover classes: green vegetation (GV), non-photosynthetic vegetation, soil, and shade. Third, we processed all Landsat scenes with &lt;50% cloud cover. Then, we applied a step-wise random forest machine learning algorithm and empirical decision rules to classify intra-annual and annual land cover classes between 1985 and 2022. Finally, we estimated the yearly land cover changes in forested and non-forested ecosystems and characterized the major change drivers. In 2022, forest covered 78.6% (331.9 Mha) of the Amazon biome, with 1.4% of secondary regrowth in more than 5 years. Total herbaceous covered 15.6% of the area, with the majority of pastureland (13.5%) and the remaining natural grassland. Water was the third largest land cover class with 2.4%, followed by cropland (1.2%) and shrubland (0.4%), with 89% overall accuracy. Most of the forest changes were driven by pasture and cropland conversion, and there are signs that climate change is the primary driver of the loss of aquatic ecosystems. Existing carbon emission models disregard the types of land cover changes presented in the studies. The twenty first century requires a more encompassing and integrated approach to monitoring anthropogenic and climate changes in the Amazon biome for better mitigation, adaptation, and conservation policies