15,880 research outputs found

    On the Distribution and Fishery Potential of the Japanese Red Crab Chaceon granulatus in the Palauan Archipelago, Western Caroline Islands

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    A deep-water trapping survey in the Palauan archipelago, Western Caroline Islands, has revealed an abundance of the Japanese red crab, Chaceon granulatus. The recorded depth range (250-900 m) is similar to that of other geryonids, but the large numbers of females caught below 700 m is atypical. Mean yields in excess of 5 kg crabs plus 1 kg shrimp, Heterocarpus laevigatus, by-catch per trap-night were attainable at optimum depths. Chaceon granulatus is apparently a very large geryonid, with maximum weights of 2.02 kg and 1.51 kg recorded for male and female specimens, respectively. A range of body colors was observed: Orange-red shades appear to dominate the deeper waters (below 500 m) while yellow-tan colors are more abundant in the upper reaches. Preliminary evidence suggests that Chaceon granulatus is highly marketable, and the infrastructure in Palau is such that crabs could either be marketed fresh locally or airfreighted to Japan as a quick-frozen product. The high post-trapping survival rates observed indicate that maintaining crabs in live-holding tanks may be a feasible option. The large catches and quality of deep-water crabs taken suggests that the Palauan population of Chaceon granulatus may be able to support a small-scale fishery. It is not yet known whether this population is unusually large or whether these findings typify the deep forereef fauna of the region

    Infinite stacking of alternating polyfluoroaryl rings and bromide anions

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    The crystal structure of 1-(4-bromo-2,3,5,6-tetrafluorophenyl)-3-benzylimidazolium bromide comprises columns of parallel bromotetrafluorophenyl rings with an interplanar distance of 6.936(6) Å separated by bromide anions

    System optimization of gasdynamic lasers, computer program user's manual

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    The user's manual for a computer program that performs system optimization of gasdynamic lasers is provided. Detailed input/output formats are CDC 7600/6600 computers using a dialect of FORTRAN. Sample input/output data are provided to verify correct program operation along with a program listing

    The significance of lifeworld and the case of hospice

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    Questions on what it means to live and die well are raised and discussed in the hospice movement. A phenomenological lifeworld perspective may help professionals to be aware of meaningful and important dimensions in the lives of persons close to death. Lifeworld is not an abstract philosophical term, but rather the opposite. Lifeworld is about everyday, common life in all its aspects. In the writings of Cicely Saunders, known as the founder of the modern hospice movement, facets of lifeworld are presented as important elements in caring for dying patients. Palliative care and palliative medicine today are, in many ways, replacing hospices. This represents not only a change in name, but also in the main focus. Hospice care was originally very much about providing support and comfort for, and interactions with the patients. Improved medical knowledge today means improved symptomatic palliation, but also time and resources spent in other ways than before. Observations from a Nordic hospice ward indicate that seriously ill and dying persons spend much time on their own. Different aspects of lifeworld and intersubjectivity in the dying persons’ room is presented and discussed

    VLBI observation of giant radio galaxy J1313+696 at 2.3/8.4 GHz

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    We report the result of VLBI observation of the giant radio galaxy J1313+696 (4C +69.15) at 2.3/8.4 GHz, only the core component of the giant radio galaxy was detected in the VLBI observation at the dual frequencies. The result shows a steep spectrum core with α=−0.82\alpha=-0.82 (S∝ναS \propto \nu^{\alpha}) between 2.3 GHz and 8.4 GHz. The steep spectrum core may be a sign of renewed activity. Considering also the upper limit flux density of 2.0 mJy at 0.6 GHz from Konar et al. 2004 the core has a GHz-peaked spectrum, implying that the core is compact and absorbed. Further high resolution VLBI observations are needed to identify if the steep spectrum core is consisting of a core and steep spectrum jet.Comment: 3 pages, 3 figure

    Band structures of rare gas solids within the GW approximation

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    Band structures for solid rare gases (Ne, Ar) have been calculated using the GW approximation. All electron and pseudopotential ab initio calculations were performed using Gaussian orbital basis sets and the dependence of particle-hole gaps and electron affinities on basis set and treatment of core electrons is investigated. All electron GW calculations have a smaller particle-hole gap than pseudopotential GW calculations by up to 0.2 eV. Quasiparticle electron and hole excitation energies, valence band widths and electron affinities are generally in very good agreement with those derived from optical absorption and photoemission measurements.Comment: 7 pages 1 figur

    An Empirically Based Calculation of the Extragalactic Infrared Background

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    Using the excellent observed correlations among various infrared wavebands with 12 and 60 micron luminosities, we calculate the 2-300 micron spectra of galaxies as a function of luminosity. We then use 12 micron and 60 micron galaxy luminosity functions derived from IRAS data, together with recent data on the redshift evolution of galaxy emissivity, to derive a new, empirically based IR background spectrum from stellar and dust emission in galaxies. Our best estimate for the IR background is of order 2-3 nW/m^2/sr with a peak around 200 microns reaching 6-8 nW/m^2/sr. Our empirically derived background spectrum is fairly flat in the mid-IR, as opposed to spectra based on modeling with discrete temperatures which exhibit a "valley" in the mid-IR. We also derive a conservative lower limit to the IR background which is more than a factor of 2 lower than our derived flux.Comment: 14 pages AASTeX, 2 .ps figures, the Astrophysical Journal, in pres

    Bonding-Compatible Corrosion Inhibitor for Rinsing Metals

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    A corrosion-inhibiting mixture of compounds has been developed for addition to the water used to rinse metal parts that have been cleaned with aqueous solutions in preparation for adhesive bonding of the metals to rubber and rubber-like materials. Prior to the development of this corrosion inhibitor, the parts (made, variously, of D6AC steel and 7075-T73 aluminum) were rinsed by deionized water, which caused corrosion in some places on the steel parts especially in such occluded places as sealing surfaces and threaded blind holes. An integral part of the particular cleaning process is the deposition of a thin layer of silicates and silane primers that increase the strength of the adhesive bond. The corrosion inhibitor is formulated, not only to inhibit corrosion of both D6AC steel and 7075- T73 aluminum, but also to either increase or at least not reduce the strength of the adhesive bond to be formed subsequently. The corrosion inhibitor is a mixture of sodium silicate and sodium tetraborate. The sodium silicate functions as both a corrosion inhibitor and a bond-strength promoter in association with the silane primers. The sodium tetraborate buffers the rinse solution at the optimum pH and functions as a secondary corrosion inhibitor for the steel. For a given application, the concentrations of sodium silicate and sodium tetraborate must be chosen in a compromise among the needs to inhibit corrosion of steel, inhibit corrosion of aluminum, and minimize cosmetic staining of both steel and aluminum. Concentrations of sodium silicate in excess of 150 parts of silicon per million parts of solution (ppm Si) have been determined to enhance inhibition of corrosion; unfortunately, because of the alkalinity of sodium silicate, even a small concentration can raise the pH of the rinse solution to such a level that aluminum becomes corroded despite the inhibiting effect. The pH of a solution that contains a high concentration of sodium silicate can be decreased by adding sodium tetraborate. On the other hand, the addition of sodium tetraborate increases the concentration of dissolved solids to such a high level that cosmetic staining becomes an issue

    Beyond jam sandwiches and cups of tea: An exploration of primary pupils' algorithm‐evaluation strategies

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    The long-standing debate into the potential benefit of developing mathematical thinking skills through learning to program has been reignited with the widespread introduction of programming in schools across many countries, including England where it is a statutory requirement for all pupils to be taught programming from five years old. Algorithm is introduced early in the English computing curriculum, yet, there is limited knowledge of how young pupils view this concept. This paper explores pupils’ (aged 10-11) understandings of algorithm following their engagement with one year of ScratchMaths (SM), a curriculum designed to develop computational and mathematical thinking skills through learning to program. 181 pupils from six schools undertook a set of written tasks to assess their interpretations and evaluations of different algorithms that solve the same problem, with a subset of these pupils subsequently interviewed to probe their understandings in greater depth. We discuss the different approaches identified, the evaluation criteria they used and the aspects of the concept that pupils found intuitive or challenging, such as simplification and abstraction. The paper ends with some reflections on the implications of the research, concluding with a set of recommendations for pedagogy in developing primary pupils’ algorithmic thinking
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