194 research outputs found

    Some haematochemical parameters of intensively farmed rainbow trout (Oncorhynchus mykiss)

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    The aim of the present study was a preliminary determination of the metabolic profile (MP) of one of the most economically valuable species on the Italian market. Defining the metabolic profile (MP) of a species is not easy because of many factors affecting the blood parameters, but assessing the normality values is necessary to identify the limits out of which a production or reproduction decrease can happen

    Contribution to the definition of the metabolic profile of farmed rainbow trout (Oncorhynchus mykiss)

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    The haematic outline of 339 rainbow trout (Oncorhynchus mykiss)from two different farms in the Lucca province was studied for a preliminary assessment of the metabolic profile of this species and for the investigation of the influence of some endogenous and exogenous factors on the variability of the studied parameters. The sampling time, as well as the weight, appears to have caused significant variations on most of the parameters analysed. The present study gives the annual means and the seasonal trends for each farm where the study was carried out

    Efficient unequal probability resampling from finite populations

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    A resampling technique for probability-proportional-to size sampling designs is proposed. It is essentially based on a special form of variable probability, without replacement sampling applied directly to the sample data, yet according to the pseudo-population approach. From a theoretical point of view, it is asymptotically correct: as both the sample size and the population size increase, under mild regularity conditions the proposed resampling design tends to coincide with the original sampling design under which sample data were collected. From a computational point of view, the proposed methodology is easy to be implemented and efficient, because it neither requires the actual construction of the pseudo-population nor any form of randomization to ensure integer weights and sizes. Empirical evidence based on a simulation study1 indicates that the proposed resampling technique outperforms its two main competitors for confidence interval construction of various population parameters including quantiles. (c) 2021 Published by Elsevier B.V

    Static Testing of a Bridge Using an Interferometric Radar: The Case Study of “Ponte degli Alpini,” Belluno, Italy

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    Ground-based radar interferometry is an increasingly popular technique for monitoring civil infrastructures. In this paper, the static testing of a bridge is reported. It was an 8-span bridge, 297 m long, named “Ponte degli Alpini,” crossing the valley of the Ardo River. The radar has been used for testing a lateral span and a central span. The obtained results present elements of novelty not previously reported in the literature. In fact, some displacement measurements of the lateral span have been affected by a horizontal shift that has to be taken into account for a correct interpretation of the measured data. Furthermore, the measurements of the central span have been carried out with the radar positioned transversally with respect to the bridge deck; this unusual arrangement has allowed for obtaining displacement maps less geometrically distorted with respect to other cases reported in the literature

    Improving the causal treatment effect estimation with propensity scores by the bootstrap

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    AbstractWhen observational studies are used to establish the causal effects of treatments, the estimated effect is affected by treatment selection bias. The inverse propensity score weight (IPSW) is often used to deal with such bias. However, IPSW requires strong assumptions whose misspecifications and strategies to correct the misspecifications were rarely studied. We present a bootstrap bias correction of IPSW (BC-IPSW) to improve the performance of propensity score in dealing with treatment selection bias in the presence of failure to the ignorability and overlap assumptions. The approach was motivated by a real observational study to explore the potential of anticoagulant treatment for reducing mortality in patients with end-stage renal disease. The benefit of the treatment to enhance survival was demonstrated; the suggested BC-IPSW method indicated a statistically significant reduction in mortality for patients receiving the treatment. Using extensive simulations, we show that BC-IPSW substantially reduced the bias due to the misspecification of the ignorability and overlap assumptions. Further, we showed that IPSW is still useful to account for the lack of treatment randomization, but its advantages are stringently linked to the satisfaction of ignorability, indicating that the existence of relevant though unmeasured or unused covariates can worsen the selection bias

    First haematic results for the sea bass (Dicentrarchus labrax) metabolic profile assessment

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    The assessment of blood reference ranges of farmed fish can be extremely useful in improving production and productquality. A first attempt to establish the normality ranges for the most important haematochemical parameters of farmedsea bass was carried out by analysing the trend of Haematocrit, Glucose, Total Protein, Albumin, Globulin, TotalCholesterol and some electrolytes in 353 sea bass farmed with two different farming systems within 1 year. A strong seasonaleffect was found with regard to each parameter; the role of some environmental conditions was evaluated; andsome reference ranges were proposed for the culturing methods considered
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