4,322 research outputs found

    Dietary Diversity and Overlap Between Two Subspecies of Spadefoot Toads (Scaphiopus holbrookii holbrookii and S. h. hurterii) in Arkansas

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    The food habits of adult spadefoot toads (Scaphiopus h. holbrookii and S. h. hurterii) collected in Arkansas were exam ined during this study. Thirty-six adult S. h. holbrookii (29 males and 7 females) and 48 adult S. h. hurterii (23 males and 2 females) were necropsied. Most specimens were collected over a 10-year span oftime (1985-94). Alltoads were taken from breeding aggregations which were visited periodically inany given year (frommid-February to late April).Prey items wer found in the stomachs of 13 (36.1%) of the S. h. holbrookii and 23 (48.0%) ofthe S. h. hurterii. Scaphiopus h. holbrookii and h. hurterii have similar diets. Both subspecies feed on a variety of ground-dwelling arthropods with 19 taxa being ident tied to the order or the familiallevel. The data suggested that there was considerable dietary overlap based upon the fa that beetles and catepillars were the primary food items. The presence ofonly one aquatic insect inall the stomachs inc cated that the toads restrict their feeding activity after arriving at breeding ponds. Additional seasonal collections ai required to better understand dietary diversity

    A note on the calculation of the effective range

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    The closed form of the first order non-linear differential equation that is satisfied by the effective range within the variable phase formulation of scattering theory is discussed. It is shown that the conventional method of determining the effective range, by fitting a numerical solution of the Schr\"odinger equation to known asymptotic boundary conditions, can be modified to include the first order contribution of a long range interaction.Comment: 4 page

    Planning, Implementing, and Evaluating a Program to Address the Oral Health Needs of Aboriginal Children in Port Augusta, Australia

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    Aboriginal Australian children experience profound oral health disparities relative to their non-Aboriginal counterparts. In response to community concerns regarding Aboriginal child oral health in the regional town of Port Augusta, South Australia, a child dental health service was established within a Community Controlled Aboriginal Health Service. A partnership approach was employed with the key aims of (1) quantifying rates of dental service utilisation, (2) identifying factors influencing participation, and (3) planning and establishing a program for delivery of Aboriginal children's dental services that would increase participation and adapt to community needs. In planning the program, levels of participation were quantified and key issues identified through semistructured interviews. After 3.5 years, the participation rate for dental care among the target population increased from 53 to 70 percent. Key areas were identified to encourage further improvements and ensure sustainability in Aboriginal child oral health in this regional location

    The variable phase method used to calculate and correct scattering lengths

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    It is shown that the scattering length can be obtained by solving a Riccati equation derived from variable phase theory. Two methods of solving it are presented. The equation is used to predict how long-range interactions influence the scattering length, and upper and lower bounds on the scattering length are determined. The predictions are compared with others and it is shown how they may be obtained from secular perturbation theory.Comment: 7 pages including 3 figure

    Fishes of the hadal zone including new species, in situ observations and depth records of Liparidae

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    AbstractObservations and records for fish exceeding 6000m deep are few and often spurious. Recent developments in accessing and sampling the hadal zone 6000–11,000m) have led to an acceleration in new findings in the deep subduction trenches, particularly in the Pacific Ocean. This study describes the discovery of two new species of snailfish (Liparidae) from the Mariana Trench; the ‘Mariana snailfish’ (6198–8076m) and the ‘Ethereal snailfish’ (7939–8145m). These new findings represent respectively the deepest known specimen caught with corroborating depth data, and the deepest fish seen alive. Further specimens and observations of the Kermadec Trench snailfish, Notoliparis kermadecensis, are also presented, as well as the first hadal records of Synaphobranchidae and Zoarcidae (6068 and 6145m respectively) and a depth extension for the Macrouridae (maximum depth now 7012m). Details of these new snailfish specimens caught by baited trap and behaviour observations filmed by baited cameras are presented. An updated assessment of fishes from hadal depths is also reported

    Distribution, composition and functions of gelatinous tissues in deep-sea fishes

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    Many deep-sea fishes have a gelatinous layer, or subdermal extracellular matrix, below the skin or around the spine. We document the distribution of gelatinous tissues across fish families (approx. 200 species in ten orders), then review and investigate their composition and function. Gelatinous tissues from nine species were analysed for water content (96.53 ± 1.78% s.d.), ionic composition, osmolality, protein (0.39 ± 0.23%), lipid (0.69 ± 0.56%) and carbohydrate (0.61 ± 0.28%). Results suggest that gelatinous tissues are mostly extracellular fluid, which may allow animals to grow inexpensively. Further, almost all gelatinous tissues floated in cold seawater, thus their lower density than seawater may contribute to buoyancy in some species. We also propose a new hypothesis: gelatinous tissues, which are inexpensive to grow, may sometimes be a method to increase swimming efficiency by fairing the transition from trunk to tail. Such a layer is particularly prominent in hadal snailfishes (Liparidae); therefore, a robotic snailfish model was designed and constructed to analyse the influence of gelatinous tissues on locomotory performance. The model swam faster with a watery layer, representing gelatinous tissue, around the tail than without. Results suggest that the tissues may, in addition to providing buoyancy and low-cost growth, aid deep-sea fish locomotion. © 2017 The Authors
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