3,235 research outputs found

    Environmental and fishing effects on the dynamic of brown tiger prawn (Penaeus esculentus) in Moreton Bay (Australia)

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    This analysis of the variations of brown tiger prawn (Penaeus esculentus) catch in the Moreton Bay multispecies trawl fishery estimated catchability using a delay difference model. It integrated several factors responsible for variations in catchability: targeting of fishing effort, increasing fishing power and changing availability. An analysis of covariance was used to define fishing events targeted at brown tiger prawns. A general linear model estimated inter-annual variations of fishing power. Temperature induced changes in prawn behaviour played an important role in the dynamic of this fishery. Maximum likelihood estimates of targeted catchability (3.92±0.40 1043.92 \pm 0.40 \ 10^{-4} boat-days1^{-1}) were twice as large as non-targeted catchability (1.91±0.24 1041.91 \pm 0.24 \ 10^{-4} boat-days1^{-1}). The causes of recent decline in fishing effort in this fishery were discussed.Comment: revised manuscript following reviewers comments + adding data and code for reader

    Hundred photon microwave ionization of Rydberg atoms in a static electric field

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    We present analytical and numerical results for the microwave excitation of nonhydrogenic atoms in a static electric field when up to 1000 photons are required to ionize an atom. For small microwave fields, dynamical localization in photon number leads to exponentially small ionization while above quantum delocalization border ionization goes in a diffusive way. For alkali atoms in a static field the ionization border is much lower than in hydrogen due to internal chaos.Comment: revtex, 4 pages, 5 figure

    Ανάπτυξη και χαρακτηρισμός ικριωμάτων νανοϋδροξυαπατίτη με την τεχνική της λυοφιλίωσης

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    Post-trawl survival (PTS) is an important metric used in determining the ecological risk posed by prawn (shrimp) trawling on discarded elasmobranchs. Despite this, PTS of elasmobranchs is poorly understood. The present study quantified the PTS of two small batoids caught incidentally by prawn trawlers in southern Queensland, Australia, namely the common stingaree (Trygonoptera testacea) and the eastern shovelnose ray (Aptychotrema rostrata). Field studies using on-board tanks revealed that A. rostrata were more resilient to trawl capture and release than T. testacea. For both species, survival was found to increase with size, whereas increasing time on deck resulted in lower survival. Female T. testacea were found to be more resilient than males, and increased tow duration resulted in lower survival for A. rostrata. The mean (+/- s.e.m.) PTS for female and male T. testacea was 33.5 +/- 6.0 and 17.3 +/- 5.5% respectively, compared with a mean PTS for A. rostrata of 86.8 +/- 3.2%. The survival estimates derived in the present study provide an insight into the effects of trawling on these species and will improve their ecological risk assessment and management

    Life-history characteristics of the eastern shovelnose ray, Aptychotrema rostrata (Shaw, 1794), from southern Queensland, Australia

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    The eastern shovelnose ray (Aptychotrema rostrata) is a medium-sized coastal batoid endemic to the eastern coast of Australia. It is the most common elasmobranch incidentally caught in the Queensland east coast otter trawl fishery, Australia’s largest penaeid-trawl fishery. Despite this, age and growth studies on this species are lacking. The present study estimated the growth parameters and age-at-maturity for A. rostrata on the basis of sampling conducted in southern Queensland, Australia. This study showed that A. rostrata exhibits slow growth and late maturity, which are common life-history strategies among elasmobranchs. Length-at-age data were analysed within a Bayesian framework and the von Bertalanffy growth function (VBGF) best described these data. The growth parameters were estimated as L0 = 193 mm TL, k = 0.08 year–1 and L∞ = 924 mm TL. Age-at-maturity was found to be 13.3 years and 10.0 years for females and males respectively. The under-sampling of larger, older individuals was overcome by using informative priors, reducing bias in the growth and maturity estimates. As such, the results can be used to derive estimates of natural mortality for this species

    Stock Assessment of Ballot's saucer scallop (Ylistrum balloti) in Queensland

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    This assessment estimates the status of saucer scallops in the main fishing grounds of the Queensland Southern Inshore fishery. The stock assessment data inputs included total harvests, standardised catch rates and fishery independent density estimates.   Analyses suggested that spawning biomass in 2019 fell to around 17 per cent of the unfished level. The report presents recommendations on fishing effort levels to begin rebuilding the stock to levels consistent with 40 per cent of unfished biomass

    Intrarater and Interrater Reliability of the Soong Classification for Distal Radius Volar Locking Plate Placement

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    Background: The purpose of this study was to analyze the intrarater and interrater reliability of the Soong classification for volar locking plate placement on a randomly selected, consecutive series of radiographs. Our hypothesis was that the classification would be reliable. Methods: Six physicians of differing levels of training (orthopedic surgery intern to fellowship-trained upper extremity staff) were asked to review 40 radiographs in a random order on 2 separate occasions, 4 weeks apart. All observers graded each image (0, 1, or 2) based on the corresponding Soong grade. A weighted κ was used to determine the intrarater agreement. The interrater agreement was determined using an intraclass coefficient: Results: The intrarater reliability using a weighted κ ranged from 0.229 (95% confidence interval [CI]: 0.048-0.411) to 0.946 (95% CI: 0.840-1.051). The interrater intraclass coefficient for Randomization 1 was 0.944 (95% 0.912-0.967) and Randomization 2 was 0.877 (95% CI: 0.797-0.930). Conclusion: The Soong classification is a reliable tool, both interrater and intrarater, for assessing distal radius volar locking plate placement. The classification system remained reliable despite a randomly selected, consecutive series of images and physician observers of varying levels of training

    Rooting Out Genetic Structure of Invasive Wild Pigs in Texas

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    Invasive wild pigs (Sus scrofa), also called feral swine or wild hogs, are recognized as among the most destructive invasive species in the world. Throughout the United States, invasive wild pigs have expanded rapidly over the past 40 years with populations now established in 38 states. Of the estimated 6.9 million wild pigs distributed throughout the United States, Texas supports approximately 40% of the population and similarly bears disproportionate ecological and economic costs. Genetic analyses are an effective tool for understanding invasion pathways and tracking dispersal of invasive species such as wild pigs and have been used recently in California and Florida, USA, which have similarly long-established populations and high densities of wild pigs. Our goals were to use molecular approaches to elucidate invasion and migration processes shaping wild pig populations throughout Texas, compare our results with patterns of genetic structure observed in California and Florida, and provide insights for effective management of this invasive species. We used a high-density single nucleotide polymorphism (SNP) array to evaluate population genetic structure. Genetic clusters of wild pigs throughout Texas demonstrate 2 distinct patterns: weakly resolved, spatially dispersed clusters and well-resolved, spatially localized clusters. The disparity in patterns of genetic structure suggests disparate processes are differentially shaping wild pig populations in various localities throughout the state. Our results differed from the patterns of genetic structure observed in California and Florida, which were characterized by localized genetic clusters. These differences suggest distinct biological and perhaps anthropogenic processes are shaping genetic structure in Texas. Further, these disparities demonstrate the need for location-specific management strategies for controlling wild pig populations and mitigating associated ecological and economic costs

    A Head Start Farm to Family Pilot Program Increased Fruit and Vegetable Intake among Families

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    Fresh Produce, Fresh Start was a pilot farm to family study which tested the effectiveness of a local produce delivery program on dietary intake of Head Start participants. Utilizing a pre-test/post-test design, measures collected from Head Start parents included 24-hour recall of dietary intake, height and weight, and a food security questionnaire. Intent-to-treat analysis was conducted using paired t-tests. Significant increases were found in intake of vitamin A, vitamin C, fiber, vegetable, and fruit and vegetable servings combined (p \u3c .05) for participants (N = 51). In particular, fruit and vegetable intake increased by 1.4 servings per day. Food security status and weight status did not significantly change. Results indicate that a produce delivery program has potential to improve dietary intake of Head Start families and, possibly, other populations, impacting lifelong consumption habit
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