2,279 research outputs found

    Distribution, Relative Abundance, and Reproductive Output of Spawning Female Blue Crab (\u3ci\u3eCallinectes sapidus\u3c/i\u3e) In Offshore Waters of the Gulf of Mexico

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    Effective assessment and management of migratory species require an understanding of stock boundaries and habitat use during critical life history periods. The blue crab (Callinectes sapidus) is considered a primarily estuarine species and has traditionally been assessed and man-aged on a state basis, relying on abundance estimates derived from estuarine sampling. Females undertake a sea-ward spawning migration, and recent evidence indicates that coastal and offshore waters may provide important spawning habitat. We investigated occurrence and reproductive output of spawning blue crab in offshore waters of the northwestern Gulf of Mexico, and results indicate that these waters may be an important spawning area for this species. Densities of blue crab were low offshore compared with those in estuaries, but given the large extent of available offshore habitat, the total abundance of adult females is likely similar in offshore and estuarine waters. Analyses of the reproductive output of females collected offshore indicate that they continue to spawn after leaving the estuaries. Fecundity and measures of egg quality were assessed and were similar to previous estimates for estuarine regions. Future management and assessment efforts should account for this previously understudied portion of the blue crab spawning stock

    The Use of an Experimental, Topical Foam to Enhance Skin Cooling and Sodium Retention

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    Acute Beet Juice Supplementation Does Not Improve 30- or 60-second Maximal Intensity Performance in Anaerobically Trained Athletes

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    International Journal of Exercise Science 14(2): 60-75, 2021. Research suggests that beet juice is beneficial during aerobic exercise. However, the impact of beet juice during primarily anaerobic exercise is equivocal. The purpose of this study was to determine the effects of acute beet juice supplementation on maximal intensity performance during 30-s and 60-s maximal-intensity cycling sprints. Using a double-blind, crossover-study design, 14 anaerobically trained male hockey players completed six Wingate cycling tests: familiarization trials of a 30-s and 60-s Wingate test, followed by 30-s Wingate placebo/beet juice trials, and 60-s Wingate placebo/beet juice trials. Repeated measures ANOVAs were used to compare the change in power between conditions over the duration of each trial. Paired t-tests were run to compare performance between conditions of various work and power variables. One-way ANOVAs were utilized to compare the change between conditions of the 30-s test to the change between conditions of the 60-s test. Beet juice supplementation yielded no statistical differences from placebo in any of the measured variables during the 30-s or 60-s tests (p \u3e 0.05). The percent change for fatigue index was significantly different between the 30-s and 60-s tests (p = 0.032) suggesting less fatigue with beet juice supplementation. Overall, beet juice did not improve maximal intensity performance during 30-s or 60-s cycling sprint tests. Performance during the 60-s bout was not impacted to a greater extent than the 30-s bout after beet juice supplementation. These results suggest that beet juice supplementation does not improve short-duration exercise performance in anaerobically trained athletes

    Drift Macroalgal Distribution In Northern Gulf of Mexico Seagrass Meadows

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    Drift macroalgae, often found in clumps or mats adjacent to or within seagrass beds, can increase the value of seagrass beds as habitat for nekton via added food resources and structural complexity. But, as algal biomass increases, it can also decrease light availability, inhibit faunal movements, smother benthic communities, and contribute to hypoxia, all of which can reduce nekton abundance. We quantified the abundance and distribution of drift macroalgae within seagrass meadows dominated by turtle grass Thalassia testudinum across the northern Gulf of Mexico and compared seagrass characteristics to macroalgal biomass and distribution. Drift macroalgae were most abundant in areas with higher seagrass shoot densities and intermediate canopy heights. We did not find significant relationships between algal biomass and point measures of salinity, temperature, or depth. The macroalgal genera Laurencia and Gracilaria were present across the study region, Agardhiella and Digenia were collected in the western Gulf of Mexico, and Acanthophora was collected in the eastern Gulf of Mexico. Our survey revealed drift algae to be abundant and widespread throughout seagrass meadows in the northern Gulf of Mexico, which likely influences the habitat value of seagrass ecosystems

    On Shape Transformations and Shape Fluctuations of Cellular Compartments and Vesicles

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    We discuss the shape formation and shape transitions of simple bilayer vesicles in context with their role in biology. In the first part several classes of shape changes of vesicles of one lipid component are described and it is shown that these can be explained in terms of the bending energy concept in particular augmented by the bilayer coupling hypothesis. In the second part shape changes and vesicle fission of vesicles composed of membranes of lipid mixtures are reported. These are explained in terms of coupling between local curvature and phase separation

    Exact solution of a linear molecular motor model driven by two-step fluctuations and subject to protein friction

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    We investigate by analytical means the stochastic equations of motion of a linear molecular motor model based on the concept of protein friction. Solving the coupled Langevin equations originally proposed by Mogilner et al. (A. Mogilner et al., Phys. Lett. {\bf 237}, 297 (1998)), and averaging over both the two-step internal conformational fluctuations and the thermal noise, we present explicit, analytical expressions for the average motion and the velocity-force relationship. Our results allow for a direct interpretation of details of this motor model which are not readily accessible from numerical solutions. In particular, we find that the model is able to predict physiologically reasonable values for the load-free motor velocity and the motor mobility.Comment: 12 pages revtex, 6 eps-figure

    Modelling pellet flow in single extrusion with DEM

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    Plasticating single-screw extrusion involves the continuous conversion of loose solid pellets into a pressurized homogeneous melt that is pumped through a shaping tool. Traditional analyses of the solids conveying stage assume the movement of an elastic solid plug at a fixed speed. However, not only the corresponding predictions fail considerably, but it is also well known that, at least in the initial screw turns, the flow of loose individual pellets takes place. This study follows previous efforts to predict the characteristics of such a flow using the discrete element method. The model considers the development of normal and tangential forces resulting from the inelastic collisions between the pellets and between them and the neighbouring metallic surfaces. The algorithm proposed here is shown to be capable of capturing detailed features of the granular flow. The predictions of velocities in the cross- and down-channel directions and of the coordination number are in good agreement with equivalent reported results. The effect of pellet size on the flow features is also discussed

    Prototyping an Egyptian revival. Laser scanning, 3D prints and sculpture to support the Echoes of Egypt exhibition

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    This paper aims to highlight the importance of 3D printing to support Cultural Heritage and related activities. We will demonstrate the advantages that a conscious employment of techniques and methods, together with the right expertise, could offer to an exhibition. We will detail the steps we took to produce a 1:1 copy of a medieval sphinx for the exhibition Echoes of Egypt: Conjuring the Land of the Pharaohs which took place at the Yale Peabody Museum of Natural History (USA). This paper highlights the project’s workflow, from the digital 3D scan, data processing, 3D printing, to the artistic finishing to prepare the object for display
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