Production and fate of the G ring arc particles due to Aegaeon (Saturn LIII)

The G ring arc hosts the smallest satellite of Saturn, Aegaeon, observed with a set of images sent by Cassini spacecraft. Along with Aegaeon, the arc particles are trapped in a 7:6 corotation eccentric resonance with the satellite Mimas. Due to this resonance, both Aegaeon and the arc material are confined to within sixty degrees of corotating longitudes. The arc particles are dust grains which can have their orbital motions severely disturbed by the solar radiation force. Our numerical simulations showed that Aegaeon is responsible for depleting the arc dust population by removing them through collisions. The solar radiation force hastens these collisions by removing most of the 10$~\mu$m sized grains in less than 40 years. Some debris released from Aegaeon's surface by meteoroid impacts can populate the arc. However, it would take 30,000 years for Aegaeon to supply the observed amount of arc material, and so it is unlikely that Aegaeon alone is the source of dust in the arc

Seasonal proteome variation in intertidal shrimps under a natural setting: connecting molecular networks with environmental fluctuations

The ability of intertidal organisms to maintain their performance via molecular and physiological adjustments under low tide, seasonal fluctuations and extreme events ultimately determines population viability. Analyzing this capacity in the wild is extremely relevant since intertidal communities are under increased climate variability owing to global changes. We addressed the seasonal proteome signatures of a key intertidal species, the shrimp Palaemon elegans, in a natural setting. Shrimps were collected during spring and summer seasons at low tides and were euthanized in situ. Environmental variability was also assessed using hand-held devices and data loggers. Muscle samples were taken for 2D gel electrophoresis and protein identification through mass spectrometry. Proteome data revealed that 55 proteins (10.6% of the proteome) significantly changed between spring and summer collected shrimps, 24 of which were identified. These proteins were mostly involved in cytoskeleton remodelling, energy metabolism and transcription regulation. Overall, shrimps modulate gene expression leading to metabolic and structural adjustments related to seasonal differences in the wild (i.e. abiotic variation and possibly intrinsic cycles of reproduction and growth). This potentially promotes performance and fitness as suggested by the higher condition index in summer-collected shrimps. However, inter-individual variation (% coefficient of variation) in protein levels was quite low (min-max ranges were 0.6-8.3% in spring and 1.2-4.8% in summer), possibly suggesting reduced genetic diversity or physiological canalization. Protein plasticity is relevant to cope with present and upcoming environmental variation related to anthropogenic forcing (e.g. global change, pollution) but low inter-individual variation may limit evolutionary potential of shrimp populations.publishe

Comparative study of tributyltin toxicity on two bacteria of the genus Bacillus

Tributyltin is a potent biocide mainly used in marine antifouling paints. Owing to its widespread distribution in coast areas and its high toxicity to aquatic organisms, the use of this compound is generally restricted and under government regulation. Despite of that, it persists in the aquatic environment. Organotins used in industry have also been detected in terrestrial environments. The persistence and high lipophilicity explain bioaccumulation. The role of bacteria in recycling organic matter prompted us to study the interaction of tributyltin with two ubiquitous bacilli, B. stearothermophilus and B. subtilis, proposed as biological indicators of pollutants with ecological impact. These bacteria have been used as suitable models for the study of toxicity mechanisms of unselective lipophilic compounds (e.g., DDT and endosulfan). Drug effects on growth parameters, oxygen consumption and membrane organization were assessed. Bacteria growth in a liquid complex medium was disturbed by concentrations of TBT as low as 25 nM (8 [mu]g L-1), close to the concentration in polluted environments. The respiratory activity is affected by TBT in both microorganisms. Membrane organization, assessed by fluorescence polarization of two fluidity probes, 1,6-diphenyl-1,3,5-hexatriene (DPH) and a propionic acid derivative (DPH-PA), was also perturbed by the xenobiotic. Alterations on growth, oxygen consumption and physical properties of membrane lipids are stronger in B. stearothermophilus as compared to B. subtilis. A putative relationship between growth inhibition and respiratory activity impairment induced by TBT and its effects on the physical behaviour of bacterial membrane lipids is suggested.http://www.sciencedirect.com/science/article/B6TCP-4GSJR3R-9/1/18e0ee5c8ce4e887466d84b850ad8ec

Enfarte agudo do miocárdio no YouTube – Is it all fake news?

Introduction and objectives: The Internet is a fundamental aspect of health information. However, the absence of quality control encourages misinformation. We aim to assess the relevance and quality of acute myocardial infarction videos shared on YouTube (www.youtube.com) in Portuguese. Methods: We analyzed 1,000 videos corresponding to the first 100 search results on YouTube using the following terms (in Portuguese): "cardiac + arrest"; "heart + attack"; "heart + thrombosis"; "coronary + thrombosis"; "infarction - brain", "myocardial + infarction" and "acute + myocardial + infarction". Irrelevant (n=316), duplicated (n=345), without audio (n=24) or non-Portuguese (n=106) videos were excluded. Included videos were assessed according to source, topic, target audience and scientific inaccuracies. Quality of information was assessed using The Health on the Net Code (HONCode from 0 to 8) and DISCERN (from 0 to 5) scores - the higher the score, the better the quality. Results: 242 videos were included. The majority were from independent instructors (n=95, 39.0%) and were addressed to the general population (n=202, 83.5%). One third of the videos (n=79) contained inaccuracies while scientific society and governmental/health institution videos had no inaccuracies. The mean video quality was poor or moderate; only one video was good quality without any inaccuracies. Governmental/health institutions were the source with the best quality videos (HONCode 4±1, DISCERN 2±1). Conclusions: One third of the videos had irrelevant information and one third of the relevant ones contained inaccuracies. The average video quality was poor; therefore it is important to define strategies to improve the quality of online health information.info:eu-repo/semantics/publishedVersio

National Registry on Cardiac Electrophysiology (2012)

Os autores analisam o número e tipo de procedimentos efectuados durante o ano de 2012 com base em inquéritos enviado aos centros nacionais que durante este ano praticaram electrofisiologia diagnóstica e de intervenção e/ou implantaram cardioversores-desfibrilhadores (CDI), e comparam estes dados com os de anos anteriores. Em 2012 foram efectuados 2561 estudos electrofisiológicos, seguidos de ablação em 2017 dos casos, o que representa uma estabilização comparativamente ao ano anterior. Registou-se um aumento de 12% no número de ablações de fibrilação auricular, que passou a representar a indicação mais frequente para ablação, ultrapassando a taquicardia por reentrada nodal auriculoventricular. O número total de primeiras implantações de CDI foi de 1048 (cerca de 100/milhão de habitantes), sendo que, destes, 375 eram CDI com ressincronização ventricular (CDI BIV). Estes dados traduzem um ligeiro decréscimo (3,3%) do número de primeiras implantações, com um aumento relativo de 10% no número de CDI BIV face ao ano anterior. No entanto, verificou-se um crescimento muito significativo no número de substituições de geradores de CDI, de que resultou um acréscimo de 3,5% no total de implantações efectuadas em 2012. São feitas algumas considerações acerca da evolução e estado actual desta actividade hospitalar e sobre alguns factores que poderão influenciar a dinâmica verificada nesta área da cardiologia de intervenção

Seleção de clones de mandioquinha-salsa em áreas naturalmente infestadas pelo nematoide-das-galhas por meio de escala de notas.

Realizou-se este trabalho com o objetivo de avaliar clones de mandioquinha-salsa quanto à reação a Meloidogyne spp. por meio da elaboração de uma escala de notas.bitstream/item/85035/1/bpd-93.pd

Flutuação populacional de nematoides em hortaliças sob sistema de plantio direto.

Resumo 579-

A polynomial time biclustering algorithm for finding approximate expression patterns in gene expression time series

<p>Abstract</p> <p>Background</p> <p>The ability to monitor the change in expression patterns over time, and to observe the emergence of coherent temporal responses using gene expression time series, obtained from microarray experiments, is critical to advance our understanding of complex biological processes. In this context, biclustering algorithms have been recognized as an important tool for the discovery of local expression patterns, which are crucial to unravel potential regulatory mechanisms. Although most formulations of the biclustering problem are NP-hard, when working with time series expression data the interesting biclusters can be restricted to those with contiguous columns. This restriction leads to a tractable problem and enables the design of efficient biclustering algorithms able to identify all maximal contiguous column coherent biclusters.</p> <p>Methods</p> <p>In this work, we propose <it>e</it>-CCC-Biclustering, a biclustering algorithm that finds and reports all maximal contiguous column coherent biclusters with approximate expression patterns in time polynomial in the size of the time series gene expression matrix. This polynomial time complexity is achieved by manipulating a discretized version of the original matrix using efficient string processing techniques. We also propose extensions to deal with missing values, discover anticorrelated and scaled expression patterns, and different ways to compute the errors allowed in the expression patterns. We propose a scoring criterion combining the statistical significance of expression patterns with a similarity measure between overlapping biclusters.</p> <p>Results</p> <p>We present results in real data showing the effectiveness of <it>e</it>-CCC-Biclustering and its relevance in the discovery of regulatory modules describing the transcriptomic expression patterns occurring in <it>Saccharomyces cerevisiae </it>in response to heat stress. In particular, the results show the advantage of considering approximate patterns when compared to state of the art methods that require exact matching of gene expression time series.</p> <p>Discussion</p> <p>The identification of co-regulated genes, involved in specific biological processes, remains one of the main avenues open to researchers studying gene regulatory networks. The ability of the proposed methodology to efficiently identify sets of genes with similar expression patterns is shown to be instrumental in the discovery of relevant biological phenomena, leading to more convincing evidence of specific regulatory mechanisms.</p> <p>Availability</p> <p>A prototype implementation of the algorithm coded in Java together with the dataset and examples used in the paper is available in <url>http://kdbio.inesc-id.pt/software/e-ccc-biclustering</url>.</p

Relações entre atributos de fertilidade e matéria orgânica em solo cultivado com hortaliças em sistemas conservacionistas.

O presente trabalho teve como objetivo identificar possíveis relações entre os atributos de fertilidade e de matéria orgânica em um Latossolo Vermelho Distrófico cultivado com hortaliças em sistemas conservacionistas há seis anos

Perturbación del drenaje venoso del territorio del tronco venoso braquiocefálico y ojo rojo en enfermo con insuficiencia renal crónica en hemodiálisis

Introducción: Pacientes en diálisis son más susceptibles a colocación de catéteres venosos centrales y en consecuencia la estenosis de vena central secundaria. Se relata un caso de un paciente en hemodiálisis con ojos rojos, que ha condicionado un diagnóstico diferencial con patologías que causan ojos rojos. Caso clínico: Hombre, 60 años, raza negra, con antecedentes de hipertensión y insuficiencia renal de etiología nefroesclerotica, en hemodiálisis desde hace 20 años. Historial de hiperemia conjuntival con 2 meses de evolución, asociado a un ligero malestar ocular. Negaba otras quejas oftalmológicas. Fue referenciado para consulta de oftalmología con un probable diagnóstico de epiescleritis. En el examen objetivo se ha observado edema de párpado y de la hemicara izquierda, asociado a ingurgitación de la vena yugular externa. Exoftalmia ligera del globo ocular izquierdo. Movimientos oculares conservados, no dolorosos y sin diplopía. Presión intraocular de 18mmHg en el ojo derecho y de 23mmHg en el izquierdo. Tortuosidad y ingurgitación de los vasos episclerales a la izquierda. Oftalmoscopia sin alteraciones. En relación a los exámenes complementarios de diagnóstico, Tomografía Axial Computarizada de cráneo y orbitas sin alteraciones. La ecografía doppler de los vasos del cuello mostró una vena yugular externa arterializada. La angiografía ha revelado estenosis del tronco venoso braquiocefálico y la vena subclavia izquierda. Realizó venoplastia con balón, verificándose mejoría del cuadro clínico. Conclusión: La obstrucción del drenaje venoso del globo ocular y órbita puede simular causas de ojo rojo y se debe siempre poner en duda en la presencia de exoftalmia, tortuosidad y dilatación de los vasos episclerales y en la subida de la presión intraocular. Esto caso reporta un caso estenosis de vena central, en que ojo rojo y edema facial eran las principiáis quejas, en un paciente en hemodiálisis con historia de catéter en la vena subclavia y en la vena yugular interna izquierda por trombosis de las fistulas arteriovenosa