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With 40% of global amphibian species threatened with extinction, captive breeding programmes are an increasingly important conservation tool. The highest priority species occur in tropical countries, which presents a number of challenges. We conducted semi-structured interviews with 25 practitioners in Latin America, Africa and Asia to investigate how the effectiveness of amphibian captive breeding programmes could be improved. A thematic analysis identified 94 barriers and enablers across 13 themes. We found that existing programmes commonly followed a reactive and often ineffective four-stage operational model. Subsequently, we developed a proactive operational model, using the barriers and enablers identified by this study, to support programme managers in the implementation of effective programmes. Our findings suggest human dimensions are often critical barriers or enablers across all stages of captive breeding programmes. We recommend the development of strategic partnerships between institutions, including zoos, NGOs, governments and captive breeding programmes, to help overcome these critical barriers and improve the effectiveness of global amphibian conservation. This operational model could be translated to captive breeding programmes for other taxa.
This article considers how enslaved salvage divers cooperated and conspired with slaveholders and white employers to salvage shipwrecks and often smuggle recovered goods into homeports, permitting them to exchange their expertise for semi-independent lives of privileged exploitation. Knowing harsh treatment could preclude diving, white salvagers cultivated reciprocal relationships with divers, promoting arduousness by avoiding coercive discipline while nurturing a sense of mutual obligation arising from collective responsibilities and material rewards. Enslaved salvagers were, in several important ways, treated like free, wage-earning men. They were well fed, receiving daily allowances of fresh meat. Most resided in seaports, were hired out, and received equal shares of recovered goods, allowing many to purchase their freedom and that of family members. Divers produced spectacular amounts of wealth for their mother countries, owners, and colonial governments, especially in the maritime colonies of Bermuda, the Bahamas, and Cayman Islands. Their expertise was not confined to maritime colonies. Even as plantation slavery was taking root during the mid-seventeenth century, salvage divers provided an important source of income for planter-merchants.
Long before the Portuguese ventured down the West African coast, many Africans had become skilled swimmers, divers and surfers. In one of their first recorded encounters, the Portuguese were amazed by the swimming and underwater diving abilities of the Africans. The Portuguese navigator Joäo Gonçalves Zarco noted that his men had considerable difficulty capturing Senegambian canoemen after they leaped into the water to avoid capture, saying “our men had very great toil in the capture of those who were swimming, for they dived like cormorants, so that they could not get hold of them.“ Slaves’ expertise in underwater diving, moreover, was one of the first African skills that New World slaveholders exploited, in the process generating considerable profit. At the turn of the seventeenth century Pieter de Marees explained that Venezuelan slaveholders sought Gold Coast Africans to employ as pearl divers, noting:
[t]hey are very fast swimmers and can keep themselves underwater for a long time. They can dive amazingly far, no less deep, and can see underwater. Because they are so good at swimming and diving, they are specially kept for that purpose in many Countries and employed in this capacity where there is a need for them, such as the Island of St. Margaret in the West Indies, where Pearls are found and brought up from the bottom by Divers.
From the Age of Discovery through the nineteenth century, the swimming and underwater diving abilities of people of African descent usually surpassed those of Westerners. Indeed, sources indicate that most whites, including sailors, could not swim. To reduce drowning deaths some philanthropists, beginning in the mid-nineteenth century, advocated that sailors and others learn to swim as a means of self-preservation. Theodorus Mason's 1879 pamphlet, The Preservation of Life at Sea, stressed that “[t]he great majority of people cannot swim, and strange as it may seem to you, there are many who follow the sea as a profession who cannot swim a stroke.” Mason then urged that as part of their instruction all US Naval Academy cadets should be taught to swim.
Nutrigenomics is the study of how constituents of the diet interact with genes, and their products, to alter phenotype and, conversely, how genes and their products metabolise these constituents into nutrients, antinutrients, and bioactive compounds. Results from molecular and genetic epidemiological studies indicate that dietary unbalance can alter gene–nutrient interactions in ways that increase the risk of developing chronic disease. The interplay of human genetic variation and environmental factors will make identifying causative genes and nutrients a formidable, but not intractable, challenge. We provide specific recommendations for how to best meet this challenge and discuss the need for new methodologies and the use of comprehensive analyses of nutrient–genotype interactions involving large and diverse populations. The objective of the present paper is to stimulate discourse and collaboration among nutrigenomic researchers and stakeholders, a process that will lead to an increase in global health and wellness by reducing health disparities in developed and developing countries.
We present likelihood-based methods for assigning the individuals in a sample to source populations, on the basis of their genotypes at co-dominant marker loci. The source populations are assumed to be at Hardy–Weinberg and linkage equilibrium, but the allelic composition of these source populations and even the number of source populations represented in the sample are treated as uncertain. The parameter of interest is the partition of the set of sampled individuals, induced by the assignment of individuals to source populations. We present a maximum likelihood method, and then a more powerful Bayesian approach for estimating this sample partition. In general, it will not be feasible to evaluate the evidence supporting each possible partition of the sample. Furthermore, when the number of individuals in the sample is large, it may not even be feasible to evaluate the evidence supporting, individually, each of the most plausible partitions because there may be many individuals which are difficult to assign. To overcome these problems, we use low-dimensional marginals (the ‘co-assignment probabilities’) of the posterior distribution of the sample partition as measures of ‘similarity’, and then apply a hierarchical clustering algorithm to identify clusters of individuals whose assignment together is well supported by the posterior distribution. A binary tree provides a visual representation of how well the posterior distribution supports each cluster in the hierarchy. These methods are applicable to other problems where the parameter of interest is a partition of a set. Because the co-assignment probabilities are independent of the arbitrary labelling of source populations, we avoid the label-switching problem of previous Bayesian methods.
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