199 research outputs found

    A COMPREHENSIVE HDL MODEL OF A LINE ASSOCIATIVE REGISTER BASED ARCHITECTURE

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    Modern processor architectures suffer from an ever increasing gap between processor and memory performance. The current memory-register model attempts to hide this gap by a system of cache memory. Line Associative Registers(LARs) are proposed as a new system to avoid the memory gap by pre-fetching and associative updating of both instructions and data. This thesis presents a fully LAR-based architecture, targeting a previously developed instruction set architecture. This architecture features an execution pipeline supporting SWAR operations, and a memory system supporting the associative behavior of LARs and lazy writeback to memory

    Improvement of a Low-cost DIY Wave Gauge

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    The impacts of waves on shorelines and nearshore ecosystems has highlighted the need for extension and other environmental professionals to have access to accurate and affordable wave measurements. The development of a low-cost DIY wave gauge improved the accessibility of these measurements; however, the original design was limited in battery life. Here, an improved version of the low-cost DIY wave gauge, the DIY Feather Wave Gauge, is presented with the same performance, longer battery life, smaller design, and cheaper cost along with tutorials, parts lists, and other resources. This new gauge has been used to improve shoreline management recommendations

    Tapered Fluidized Beds and the Role of Fluidization in Mineral Emplacement

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    One of the most prominent features of fluidized beds is their ability to mix and segregate. This is of great importance for many industrial processes, but takes on a particular significance for mineral extraction where a small amount of valuable matter is mixed with a large amount of waste. In this study we consider the occurrence of diamonds in the volcanic rock called “kimberlite”. These are often emplaced (erupted and deposited) in large volcanic pipes commonly referred to as “diatremes” (length scale of the order of a kilometre) with a vent at the bottom through which the minerals were introduced along with other fragmental particulate matter and a gas flow. The purpose of this study is to gain an understanding of the processes that led to the dispersal of minerals before their emplacement to allow efficient extraction. The paper describes experimental observations of a tapered fluidized bed. The objective was to identify the physical behaviour of gas and particles; so, of particular interest are the extent to which fluidization takes place within the bed, and the arrangements of particles seen. Gas flow-rate, particle size, and degree of taper were all varied. These observations can be used to identify the structures and processes that can take place; it is then possible to understand field data in terms of the physics that led to the emplacement of material. This will be shown using new data taken from southern Africa. Scale-up of evidence is of obvious difficulty in this system and this is discussed in terms of the possible behaviour of the bubbles that have generated mixing of material before emplacement

    Optical Polarization and Spectral Variability in the M87 Jet

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    During the last decade, M87's jet has been the site of an extraordinary variability event, with one knot (HST-1) increasing by over a factor 100 in brightness. Variability was also seen on timescales of months in the nuclear flux. Here we discuss the optical-UV polarization and spectral variability of these components, which show vastly different behavior. HST-1 shows a highly significant correlation between flux and polarization, with P increasing from ∌20\sim 20% at minimum to >40% at maximum, while the orientation of its electric vector stayed constant. HST-1's optical-UV spectrum is very hard (αUV−O∌0.5\alpha_{UV-O}\sim0.5, FΜ∝Μ−αF_\nu\propto\nu^{-\alpha}), and displays "hard lags" during epochs 2004.9-2005.5, including the peak of the flare, with soft lags at later epochs. We interpret the behavior of HST-1 as enhanced particle acceleration in a shock, with cooling from both particle aging and the relaxation of the compression. We set 2σ\sigma upper limits of 0.5ÎŽ0.5 \delta parsecs and 1.02cc on the size and advance speed of the flaring region. The slight deviation of the electric vector orientation from the jet PA, makes it likely that on smaller scales the flaring region has either a double or twisted structure. By contrast, the nucleus displays much more rapid variability, with a highly variable electric vector orientation and 'looping' in the (I,P)(I,P) plane. The nucleus has a much steeper spectrum (αUV−O∌1.5\alpha_{UV-O} \sim 1.5) but does not show UV-optical spectral variability. Its behavior can be interpreted as either a helical distortion to a steady jet or a shock propagating through a helical jet.Comment: 14 pages, 7 figures, ApJ, in pres

    Nutritional Supplement Use in a UK High-Performance Swimming Club

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    The aim of this study was to observe the nutritional supplement practices of highly trained swimmers on a national talent pathway, since it is often reported that swimmers engage in widespread supplement use at the elite level. Thus, this study employed a validated supplement intake questionnaire with forty-four swimmers from a high-performance swimming club, which had three distinct talent stages: development (aged 11–14 years, n = 20), age-group (aged 13–17 years, n = 13), and national level (aged ≄ 16 years, n = 11). Ninety-eight percent of the interviewed swimmers reported using at least one supplement, with performance (34%) and recovery (19%) cited as the primary reasons. National swimmers used more total supplements (8.1 ± 3.4 supplements) compared to age-group (4.8 ± 2.0 supplements, p = 0.003, g = 1.17) and development (3.9 ± 1.7 supplements, p < 0.001, g = 1.69) swimmers, mostly because of a greater intake of ergogenic aids (2.4 ± 1.4 supplements vs. age-group: 0.5 ± 0.5 supplements, p < 0.001, g = 1.12; vs. development: 0.1 ± 0.2 supplements, p < 0.001, g = 1.81). Parents/guardians were the primary supplement informants of development swimmers (74%, p < 0.001, V = 0.50), whereas performance nutritionists informed ~50% of supplements used by age-group and national swimmers (p < 0.001, V = 0.51). Based on these results, supplement education and greater focus on basic sport nutrition practices may be required for parents/guardians at the development level. Moreover, further research is needed to support the high number of ergogenic aids used by national swimmers, with the efficacy of these supplements currently equivocal in the applied setting

    Biofluorescence in Catsharks (Scyliorhinidae): Fundamental Description and Relevance for Elasmobranch Visual Ecology

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    Biofluorescence has recently been found to be widespread in marine fishes, including sharks. Catsharks, such as the Swell Shark (Cephaloscyllium ventriosum) from the eastern Pacific and the Chain Catshark (Scyliorhinus retifer) from the western Atlantic, are known to exhibit bright green fluorescence. We examined the spectral sensitivity and visual characteristics of these reclusive sharks, while also considering the fluorescent properties of their skin. Spectral absorbance of the photoreceptor cells in these sharks revealed the presence of a single visual pigment in each species. Cephaloscyllium ventriosum exhibited a maximum absorbance of 484 ± 3 nm and an absorbance range at half maximum (λ1/2max) of 440–540 nm, whereas for S. retifer maximum absorbance was 488 ± 3 nm with the same absorbance range. Using the photoreceptor properties derived here, a “shark eye” camera was designed and developed that yielded contrast information on areas where fluorescence is anatomically distributed on the shark, as seen from other sharks’ eyes of these two species. Phylogenetic investigations indicate that biofluorescence has evolved at least three times in cartilaginous fishes. The repeated evolution of biofluorescence in elasmobranchs, coupled with a visual adaptation to detect it; and evidence that biofluorescence creates greater luminosity contrast with the surrounding background, highlights the potential importance of biofluorescence in elasmobranch behavior and biology

    Nutritional intakes of highly trained adolescent swimmers before, during, and after a national lockdown in the COVID-19 pandemic

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    Strict lockdown measures were introduced in response to the COVID-19 pandemic, which caused mass disruption to adolescent swimmers’ daily routines. To measure how lockdown impacted nutritional practices in this cohort, three-day photograph food diaries were analysed at three time points: before (January), during (April), and after (September) the first UK lockdown. Thirteen swimmers (aged 15 ± 1 years) from a high-performance swimming club submitted satisfactory food diaries at all time points. During lockdown, lower amounts of energy (45.3 ± 9.8 vs. 31.1 ± 7.7 kcal∙kg BM∙day-1, p0.05), despite fewer training hours being completed (15.0 ± 1.4 vs. 19.1 ± 2.2 h∙week-1, p<0.001). These findings highlight the ability of adolescent swimmers to alter their nutrition based on their changing training circumstances when receiving sport nutrition support. However, some individuals displayed signs of suboptimal nutrition during lockdown that were not corrected once training resumed. This warrants future research to develop interactive education workshops that maintain focus and motivation towards optimal nutrition practices in isolated periods away from training

    Why Not Nephrology? A Survey of US Internal Medicine Subspecialty Fellows

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    There is a decreased interest in nephrology such that the number of trainees likely will not meet the upcoming workforce demands posed by the projected number of patients with kidney disease. We conducted a survey of US internal medicine subspecialty fellows in fields other than nephrology to determine why they did not choose nephrology
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