26 research outputs found

    An analysis of life expectancy and economic production using expectile frontier zones

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    The wealth of a country is assumed to have a strong non-linear influence on the life expectancy of its inhabitants. We follow up on research by Preston and study the relationship with gross domestic product. Smooth curves for the average but also for (upper) frontiers are constructed by a combination of least asymmetrically weighted squares and P-splines. Guidelines are given for optimizing the amount of smoothing and the definition of frontiers. The model is applied to a large set of countries in different years. It is also used to estimate life expectancy performance for individual countries and to show how it changed over time.frontier estimation, gross domestic product, least asymmetrically weighted squares, life expectancy, production frontier, smoothing

    Monitoring strawberry production to get grip on strawberry quality : GreenCHAINge Fruit & Vegetables WP3

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    The Greenchainge project is a large project financially supported by the industry and Foundation TKI Horticulture comprising different sub-projects focussing on different fruit and vegetable products. One of the sub-projects (work package 3) is dedicated to strawberry and is carried out with and by Driscoll’s BV, Bakker Barendrecht BV and Wageningen Food and Biobased Research (WFBR). One of the main goals of the soft fruit project is to contribute to the understanding of strawberry quality and as such pave the way towards controlling quality to supply high and constant strawberry quality. Therefore, one of the key research question in this project is which chain parameters affect quality directly. Hence, a large-scale quality monitoring research was set up together with the companies involved in the project. The main goal of this monitoring research was to get insight in the pre and post-harvest parameters that influence the quality of strawberries, meaning the quality at harvest and shelf life

    An analysis of life expectancy and economic production using expectile frontier zones

    Get PDF
    The wealth of a country is assumed to have a strong non-linear influence on the life expectancy of its inhabitants. We follow up on research by Preston and study the relationship with gross domestic product. Smooth curves for the average but also for upper frontiers are constructed by a combination of least asymmetrically weighted squares and P-splines. Guidelines are given for optimizing the amount of smoothing and the definition of frontiers. The model is applied to a large set of countries in different years. It is also used to estimate life expectancy performance for individual countries and to show how it changed over time

    Global Diversity of Brittle Stars (Echinodermata: Ophiuroidea)

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    This review presents a comprehensive overview of the current status regarding the global diversity of the echinoderm class Ophiuroidea, focussing on taxonomy and distribution patterns, with brief introduction to their anatomy, biology, phylogeny, and palaeontological history. A glossary of terms is provided. Species names and taxonomic decisions have been extracted from the literature and compiled in The World Ophiuroidea Database, part of the World Register of Marine Species (WoRMS). Ophiuroidea, with 2064 known species, are the largest class of Echinodermata. A table presents 16 families with numbers of genera and species. The largest are Amphiuridae (467), Ophiuridae (344 species) and Ophiacanthidae (319 species). A biogeographic analysis for all world oceans and all accepted species was performed, based on published distribution records. Approximately similar numbers of species were recorded from the shelf (n = 1313) and bathyal depth strata (1297). The Indo-Pacific region had the highest species richness overall (825 species) and at all depths. Adjacent regions were also relatively species rich, including the North Pacific (398), South Pacific (355) and Indian (316) due to the presence of many Indo-Pacific species that partially extended into these regions. A secondary region of enhanced species richness was found in the West Atlantic (335). Regions of relatively low species richness include the Arctic (73 species), East Atlantic (118), South America (124) and Antarctic (126)

    Optimal expectile smoothing

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    Quantiles are computed by optimizing an asymmetrically weighted L1 norm, i.e. the sum of absolute values of residuals. Expectiles are obtained in a similar way when using an L2 norm, i.e. the sum of squares. Computation is extremely simple: weighted regression leads to the global minimum in a handful of iterations. Least asymmetrically weighted squares are combined with P-splines to compute smooth expectile curves. Asymmetric cross-validation and the Schall algorithm for mixed models allow efficient optimization of the smoothing parameter. Performance is illustrated on simulated and empirical data.

    Developing a feasible and sensitive judgement bias task in dairy cows

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    Judgement bias tasks (JBTs) are used to assess the influence of farm practices on livestock affective states. The tasks must be adjusted to the species and age group of focus. In cattle, most JBTs were designed for calves instead of adult cows. This study aimed to develop a JBT suitable for adult dairy cows, combining feasibility, validity, sensitivity and repeatability. Three JBTs were developed in which cows were trained to reach or avoid reaching a feeder, the location of which signalled a reward or punisher. The tasks differed in terms of punisher—cows being allocated either to “no-reward”, an air puff or an electric shock. Cows were then exposed twice to three ambiguous positions of the feeder, on two separate occasions. Speed of learning and proportions of correct responses to the conditioned locations were used to assess the feasibility of the task. Adjusted latencies to reach the ambiguous feeder positions were used to examine whether response patterns matched the linear and monotonic graded pattern expected in a valid and sensitive JBT at baseline. Latencies to reach the feeders in the two repeated testing sessions were compared to assess ambiguity loss over tasks’ repetitions. The validity of using spatial JBTs for dairy cows was demonstrated. While the effect on JBT feasibility was nuanced, the punisher did influence JBT sensitivity. None of the JBTs’ repeatability could be supported. We conclude that using an air puff as punisher led to the most sensitive, yet non-repeatable—BT for dairy cows

    Correction to : Developing a feasible and sensitive judgement bias task in dairy cows (Animal Cognition, (2021), 10.1007/s10071-021-01563-8)

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    In the Original publication of the article, the second author name was incorrectly published as Cornelius G. van Reenen, the correct name should read as Cornelis G. van Reenen. This has been corrected in this paper. In addition, at the end of the abstract, it is written “We conclude that using an air puff as punisher led to the most sensitive, yet non-repeatable—BT for dairy cows”. The correct should read as; “We conclude that using an air puff as punisher led to the most sensitive, yet non-repeatable, JBT for dairy cows”. This has been corrected here
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