7,987 research outputs found

    Simulation of Tail Weight Distributions in Biological Year 1986–2006 Landings of Brown Shrimp, Farfantepenaeus aztecus, from the Northern Gulf of Mexico Fishery

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    Size distribution within re- ported landings is an important aspect of northern Gulf of Mexico penaeid shrimp stock assessments. It reflects shrimp population characteristics such as numerical abundance of various sizes, age structure, and vital rates (e.g. recruitment, growth, and mortality), as well as effects of fishing, fishing power, fishing practices, sampling, size-grading, etc. The usual measure of shrimp size in archived landings data is count (C) the number of shrimp tails (abdomen or edible portion) per pound (0.4536 kg). Shrimp are marketed and landings reported in pounds within tail count categories. Statistically, these count categories are count class intervals or bins with upper and lower limits expressed in C. Count categories vary in width, overlap, and frequency of occurrence within the landings. The upper and lower limits of most count class intervals can be transformed to lower and upper limits (respectively) of class intervals expressed in pounds per shrimp tail, w, the reciprocal of C (i.e. w = 1/C). Age based stock assessments have relied on various algorithms to estimate numbers of shrimp from pounds landed within count categories. These algorithms required un- derlying explicit or implicit assumptions about the distribution of C or w. However, no attempts were made to assess the actual distribution of C or w. Therefore, validity of the algorithms and assumptions could not be determined. When different algorithms were applied to landings within the same size categories, they produced different estimates of numbers of shrimp. This paper demonstrates a method of simulating the distribution of w in reported biological year landings of shrimp. We used, as examples, landings of brown shrimp, Farfantepenaeus aztecus, from the northern Gulf of Mexico fishery in biological years 1986–2006. Brown shrimp biological year, Ti, is defined as beginning on 1 May of the same calendar year as Ti and ending on 30 April of the next calendar year, where subscript i is the place marker for biological year. Biological year landings encompass most if not all of the brown shrimp life cycle and life span. Simulated distributions of w reflect all factors influencing sizes of brown shrimp in the landings within a given biological year. Our method does not require a priori assumptions about the parent distributions of w or C, and it takes into account the variability in width, overlap, and frequency of occurrence of count categories within the landings. Simulated biological year distributions of w can be transformed to equivalent distributions of C. Our method may be useful in future testing of previously applied algorithms and development of new estimators based on statistical estimation theory and the underlying distribution of w or C. We also examine some applications of biological year distributions of w, and additional variables derived from them

    World Administrative Radio Conference

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    World Administrative Radio Conference

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    AIR LAW - LEGAL STATUS OF AIRPLANE FLIGHT

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    The classical statement of the extent of the landowner\u27s right to the air space above his land is the maxim, Cujus est solum ejus est usque ad coelum. It is recognized, however, that decisions stating such a rule are not in point upon the status of air navigation today, for when those decisions were rendered flights were made in fancy only. Hence it is that all cases deciding this modern problem have disregarded the literal meaning of this maxim and tried to strike a compromise between the claims of air navigation and the claims of ownership. Three theories have been advanced to this end: (1) that the landowner owns the airspace above to an unlimited height, but is subject to an easement of travel in the public; (2) that he owns the air space within an indeterminate zone, but beyond that zone the ownership is vacant; (3) that his ownership extends no further upward than the earth\u27s surface, including any growth and buildings. This last theory, using the nature of the action given as descriptive of the right, is called the nuisance theory. In any appraisal of these theories, our aim ought to be to determine which best secures the landowner in his legitimate interests, yet, at the same time, secures aerial freedom sufficient to meet the public interest involved

    Effect of moisture on cadmium sulfide solar cells

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    Moisture effect on thin-film cadmium-sulfide solar cell

    Gaps in knowledge and future directions for the use of faecal microbiota transplant in the treatment of inflammatory bowel disease

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    Faecal microbiota transplant (FMT) has now been established into clinical guidelines for the treatment of recurrent and refractory Clostridioides difficile infection (CDI). Its therapeutic application in inflammatory bowel disease (IBD) is currently at an early stage. To date there have been four randomised controlled trials for FMT in IBD and a multitude of observational studies. However significant gaps in our knowledge regarding optimum methods for FMT preparation, technical and logistics of its administration, as well as mechanistic underpinnings, still remain. This article aims to highlight these gaps by reviewing evidence and makes key recommendations on the direction of future studies in this field. In addition, we provide an overview of the current evidence of potential mechanistics of FMT in IBD

    White matter changes and confrontation naming in retired aging national football league athletes

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    Using diffusion tensor imaging (DTI), we assessed the relationship of white matter integrity and performance on the Boston Naming Test (BNT) in a group of retired professional football players and a control group. We examined correlations between fractional anisotropy (FA) and mean diffusivity (MD) with BNT T-scores in an unbiased voxelwise analysis processed with tract-based spatial statistics (TBSS). We also analyzed the DTI data by grouping voxels together as white matter tracts and testing each tract's association with BNT T-scores. Significant voxelwise correlations between FA and BNT performance were only seen in the retired football players (p < 0.02). Two tracts had mean FA values that significantly correlated with BNT performance: forceps minor and forceps major. White matter integrity is important for distributed cognitive processes, and disruption correlates with diminished performance in athletes exposed to concussive and subconcussive brain injuries, but not in controls without such exposure

    Detailed Inspection of Metal Implants

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    Detailed visual inspection of metal hips is the first step in retrieval analysis. In this study a systematic visual inspection protocol was developed to quantify bearing surface changes and their associations with material loss was investigated. Simple and multiple linear regression models found that moderate surface scratching, discolouration, haziness and the size of visible wear scars were all significantly associated with material loss (R2 = 5% - 73%, p<0.05). Visual inspection is not a substitute for measurement of material loss but an understanding of bearing surface changes may offer unique clues as to the mechanisms of failure of retrieved hips
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