809 research outputs found

    Stellar Populations in Barred Galaxies

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    We developed an iterative technique to better characterize stellar populations and the central activity of barred galaxies using evolutionary synthesis codes and OASIS data. The case of NGC5430 is presented here. Our results are reinforcing the role played by the bar and nuclear structures for the evolution of galaxies.Comment: 2 pages, 1 figure, to be published in the proceedings of IAU Symp. 262 "Stellar Populations - Planing for the Next Decate" (Aug. 2009

    Primary structure of a high Mr form of rat atrial natriuretic factor

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    AbstractDuring the purification of rat atrial natriuretic factor (ANF), low, intermediate and high Mr forms were observed. In this report we describe the purification and amino acid sequence of a 73 residue peptide containing at its C-terminus the previously sequenced 33 amino acid ANF peptide. The cleabage necessary to produce the 33 amino acid ANF from the 73 amino acid precursor occurs at a Leuî—¸Leu bond. We also report the amino acid composition of an even longer form of ANF containing about 103 residues, in which the extension is amino terminal to the 73 peptide. A computer data bank search showed that the determined sequence is a novel one and is not homologous to any known proteins or segment thereof. The natriuretic activity of the 73 amino acid form when compared to that of a synthetic ANF peptide, comprising the sequence of the last 26 amino acids of ANF, was found to be slightly lower

    Joint Optical Flow and Temporally Consistent Semantic Segmentation

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    The importance and demands of visual scene understanding have been steadily increasing along with the active development of autonomous systems. Consequently, there has been a large amount of research dedicated to semantic segmentation and dense motion estimation. In this paper, we propose a method for jointly estimating optical flow and temporally consistent semantic segmentation, which closely connects these two problem domains and leverages each other. Semantic segmentation provides information on plausible physical motion to its associated pixels, and accurate pixel-level temporal correspondences enhance the accuracy of semantic segmentation in the temporal domain. We demonstrate the benefits of our approach on the KITTI benchmark, where we observe performance gains for flow and segmentation. We achieve state-of-the-art optical flow results, and outperform all published algorithms by a large margin on challenging, but crucial dynamic objects.Comment: 14 pages, Accepted for CVRSUAD workshop at ECCV 201

    Purification of three rat atrial natriuretic factors and their amino acid composition

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    AbstractA natriuretic factor has been described in the specific granules of rat atria. We have purified three factors which seem to be low-Mr peptides. They have been purified by means of acid extraction, octadecyl Sep-Pak cartridges, and chromatography on Bio-Gel P-10, CM Bio-Gel A, Mono S and reverse-phase high-performance liquid chromatography columns. The factors contain 26, 31 and 33 amino acids and may have been partially degraded during isolation. They are all 3 biologically active and the shorter one is the most active with a specific activity of 450000 units/mg

    Estimulación eléctrica en la reparación ósea de defectos creados en cráneos de conejos

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    Electrical stimulation has been used in different conditions for tissue regeneration. The aim of this study was to analyze the tissue response of defects created in rabbit skulls to electrical stimulation. Two groups were formed, each with 9 New Zealand rabbits; two 5 mm defects were made, one in each parietal, with one being randomly filled with autogenous bone extracted as particles and the other maintained only with blood clotting. The rabbits were euthanized at 8 weeks and 15 weeks to then study the samples collected histologically. In the 8-week analysis bone formation was observed in the defects in the test and control filled with bone graft, whereas the defects with clotting presented a very early stage of bone formation with abundant connective tissue. At 15 weeks an advanced stage of bone regeneration was identified in the defects with bone graft, whereas no significant differences were found in the electrically stimulated defects. In conclusion, electrical stimulus does not alter the sequence of bone formation; new studies could help establish patterns and influences of the stimulus on bone regeneration.Electrical stimulation has been used in different conditions for tissue regeneration. The aim of this study was to analyze the tissue response of defects created in rabbit skulls to electrical stimulation. Two groups were formed, each with 9 New Zealand r33311461150sem informaçãosem informaçãoLa estimulación eléctrica ha sido empleada en diferentes condiciones para la regeneración de tejidos. El objetivo de esta investigación es analizar la respuesta tisular de defectos creados en cráneo de conejos a la estimulación eléctrica. Se formaron 2 g

    Executive functioning predicts reading, mathematics, and theory of mind during the elementary years.

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    The goal of this study was to specify how executive functioning components predict reading, mathematics, and theory of mind performance during the elementary years. Ninety-three 7- to 10-year-old children completed measures of working memory, inhibition, flexibility, reading, mathematics, and theory of mind. Path analysis revealed that all three executive functioning components (working memory, inhibition, and flexibility) mediated age differences in reading comprehension, whereas age predicted mathematics and theory of mind directly. In addition, reading mediated the influence of executive functioning components on mathematics and theory of mind, except that flexibility also predicted mathematics directly. These findings provide important details about the development of executive functioning, reading, mathematics, and theory of mind during the elementary years

    Lower limb biomechanics during drop jump landing in individuals with chronic ankle instability

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    ABSTRACT Context: Individuals with chronic ankle instability (CAI) exhibit impaired lower limb biomechanics during unilateral drop jump landing on a flat surface. However, lower limb biomechanical adaptations during unilateral drop jump landing on more challenging surfaces such as unstable or inclined are yet to be described. Objective: Determine how unilateral drop jump landing surfaces (flat, unstable and inclined) influence lower limb EMG, kinematics and kinetics in individuals with CAI. Design: Descriptive laboratory study. Setting: Biomechanics laboratory. Patients or Other Participants: Twenty-two young adults with CAI Interventions: Participants completed five trials of unilateral drop jump landing from a 46 cm height platform on flat (DROP), unstable (FOAM) and laterally inclined (WEDGE) surfaces. Main outcome measure(s): EMG of gluteus medius, vastus lateralis, gastrocnemius medialis, peroneus longus and tibialis anterior muscles were recorded. Knee and ankle angles and moments were calculated using a three-dimensional motion analysis system and a force plate. Biomechanical variables were compared between tasks using one-dimensional statistical nonparametric mapping. Results: During DROP, greater ankle dorsiflexion angles, knee extension moments and vastus lateralis muscle activity (FOAM only) were observed compared to FOAM and WEDGE. Greater ankle inversion angles were observed during FOAM and WEDGE compared to DROP. Peroneus longus muscle activity was greater during DROP compared to FOAM. During FOAM, greater ankle inversion and knee extension angles, ankle inversion and internal rotation moments as well as smaller peroneus longus muscle activity were observed compared to WEDGE. Conclusions: The greater ankle inversion and plantarflexion angles as well as the lack of increase in peroneus longus muscle activation during FOAM and WEDGE could increase the risk of recurrent LAS in individuals with CAI. The results of this study improve our understanding of lower limb biomechanics changes when landing on more challenging surfaces and will help clinicians better targeting deficits associated with CAI during rehabilitation

    Lower limb biomechanics in individuals with chronic ankle instability during gait: a case-control study

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    Individuals with chronic ankle instability (CAI) exhibit many biomechanical changes to lower limbs during walking. However, only a few studies have investigated the differences in lower limb biomechanics of individuals with CAI compared to healthy controls using a comprehensive approach including kinematic, kinetic and electromyography (EMG) measures. Consequently, the theoretical framework explaining the biomechanical adaptations in individuals with CAI is mostly based on the results of studies including heterogenous methods and participants’ specificities (e.g., level of disability). More studies using a comprehensive approach are needed to better understand the biomechanical adaptations associated with CAI. The objective of this case-control study was to identify the kinematic, kinetic and EMG differences between individuals with CAI and healthy controls during walking

    Real-time PCR reveals a high incidence of Symbiodinium clade D at low levels in four scleractinian corals across the Great Barrier Reef:Implications for symbiont shuffling

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    Reef corals form associations with an array of genetically and physiologically distinct endosymbionts from the genus Symbiodinium. Some corals harbor different clades of symbionts simultaneously, and over time the relative abundances of these clades may change through a process called symbiont shuffling. It is hypothesized that this process provides a mechanism for corals to respond to environmental threats such as global warming. However, only a minority of coral species have been found to harbor more than one symbiont clade simultaneously and the current view is that the potential for symbiont shuffling is limited. Using a newly developed real-time PCR assay, this paper demonstrates that previous studies have underestimated the presence of background symbionts because of the low sensitivity of the techniques used. The assay used here targets the multi-copy rDNA ITS1 region and is able to detect Symbiodinium clades C and D with > 100-fold higher sensitivity compared to conventional techniques. Technical considerations relating to intragenomic variation, estimating copy number and non-symbiotic contamination are discussed. Eighty-two colonies from four common scleractinian species (Acropora millepora, Acropora tenuis, Stylophora pistillata and Turbinaria reniformis) and 11 locations on the Great Barrier Reef were tested for background Symbiodinium clades. Although these colonies had been previously identified as harboring only a single clade based on SSCP analyses, background clades were detected in 78% of the samples, indicating that the potential for symbiont shuffling may be much larger than currently thought

    Branching coral growth and visual health during bleaching and recovery on the central Great Barrier Reef

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    Coral reefs are under threat from cumulative impacts such as cyclones, crown-of-thorns starfish (COTS) outbreaks and climate-driven coral bleaching events. Branching corals are more severely impacted by these events than other coral morphologies due to their sensitivity to heat stress and weaker skeletons and COTS preferred prey. The central Great Barrier Reef experienced unprecedented back-to-back bleaching events in 2016 and 2017. This study commenced in 2017 at the peak of heat stress and examined the impact of the heatwave on the survival and recovery of corals by assessing the growth, health (based on the visual health index) and physiological parameters (chlorophyll a, zooxanthellae density, lipid and protein content) of two species, Acropora millepora and Pocillopora acuta (N = 60 colonies for each species). It was conducted across a gradient of turbidity at three reefs, Pandora, Orpheus and Rib, that experienced in April 2017, degree heating weeks (DHW) of 9, 8 and 7, respectively. Orpheus experienced the worst bleaching, based on visual health score, followed by Rib and Pandora. Rib experienced the greatest mortality (78% by Nov 2017); however, this was attributed to the presence of actively feeding crown-of-thorns starfish. Growth rates of A. millepora were almost twice the rate of P. acuta. Both species showed significant seasonal variation with growth of A. millepora and P. acuta 35–40% and 23–33% significantly greater in the summer, respectively. Differences in growth rates were best explained by indicators of energy acquisition. For example, the most important predictor variable in determining higher growth rates and visual health score in A. millepora was chlorophyll a content. For P. acuta, visual health score was the best predictor variable for higher growth rates. This study highlights the important role that chlorophyll a and associated symbionts play in growth and survival in these corals during and after a heat stress event
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