314 research outputs found

    PastoralScape : an environment-driven model of vaccination decision making within pastoralist groups in East Africa

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    Economic and cultural resilience among pastoralists in East Africa is threatened by the interconnected forces of climate change and contagious diseases spread. A key factor in the resilience of livestock dependent communities is human decision making regarding vaccination against preventable diseases such as Rift Valley fever and Contagious Bovine Pleuropneumonia. The relationship between healthy and productive livestock and economic development of poor households and communities is mediated by human decision making. This paper describes a coupled human and natural systems agent-based model that focuses on One Health. Disease propagation and animal nutritional health are driven by historical GIS data that captures changes in foraging condition. The results of a series of experiments are presented that demonstrate the sensitivity of a transformed Random Field Ising Model of human decision making to changes in human memory and rationality parameters. Results presented communicate that convergence in the splitting of households between vaccinating or not is achieved for combinations of memory and rationality. The interaction of these cognition parameters with public information and social networks of opinions is detailed. This version of the PastoralScape model is intended to form the basis upon which richer economic and human factor models can be built. © 2021, University of Surrey. All rights reserved

    Reproductive strategies of cotton-top tamarins

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    The reproductive strategies of cotton-top tamarins (Saguinus oedipus) were investigated over a 2.5-year period in a captive breeding colony. Groups ranged in size from two to 14. The care of 21 infant tamarins was investigated over the first 12 weeks of life. Infants in larger families received more care than those in smaller families; singleton infants were carried more than twins. Parents provided more care than older siblings (helpers); older helpers provided more care than younger helpers. Individual contributions to care, particularly of fathers, declined as group size increased. There was evidence that tamarins competed to carry infants, and that some individuals attempted to restrict carrying by others. Tamarins carrying infants spent significantly less time feeding, foraging and moving than they did when not carrying, due partly to a decrease in general mobility, and partly to an increase in the time they spent concealed, presumably to avoid predation. The behaviour of five breeding pairs was observed for approximately 12 weeks before and 12 weeks after birth. During lactation, breeding females increased their feeding and foraging times to levels up to twice as high as those seen in pregnancy. There was evidence that breeding females attempted to encourage males to stay nearby to help with infant care by increasing grooming, and proceptive and receptive behaviour, shortly before postpartum. However, females were most attractive to males during the first weeks postpartum. Males mounted females significantly more often when carrying infants, suggesting that they might be using infants as part of a courtship strategy. Observations of a polyandrous group showed that the female had no preferred sexual partner. All three males in the group mated with her, and did not interfere in one another's copulations. A daughter in another group became pregnant and gave birth to a stillborn infant.There was no evidence of aggression between her and her parents.The possible benefit to be gained from a communal rearing system by both breeding and helping tamarins are discussed, and some predictions put forward to guide further research

    Using MapReduce Streaming for Distributed Life Simulation on the Cloud

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    Distributed software simulations are indispensable in the study of large-scale life models but often require the use of technically complex lower-level distributed computing frameworks, such as MPI. We propose to overcome the complexity challenge by applying the emerging MapReduce (MR) model to distributed life simulations and by running such simulations on the cloud. Technically, we design optimized MR streaming algorithms for discrete and continuous versions of Conway’s life according to a general MR streaming pattern. We chose life because it is simple enough as a testbed for MR’s applicability to a-life simulations and general enough to make our results applicable to various lattice-based a-life models. We implement and empirically evaluate our algorithms’ performance on Amazon’s Elastic MR cloud. Our experiments demonstrate that a single MR optimization technique called strip partitioning can reduce the execution time of continuous life simulations by 64%. To the best of our knowledge, we are the first to propose and evaluate MR streaming algorithms for lattice-based simulations. Our algorithms can serve as prototypes in the development of novel MR simulation algorithms for large-scale lattice-based a-life models.https://digitalcommons.chapman.edu/scs_books/1014/thumbnail.jp

    Habitat manipulation – as a pest management tool in vegetable and fruit cropping systems, with the focus on insects and mites

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    Today, there is increasing interest among Swedish growers in biological diversity within the agricultural landscape. Many scientific studies have highlighted the services performed by beneficial organisms, which can help to improve the quantity and quality of crops. One tremendously important ecosystem service is biological control of pest insects and mites. The question is what growers can actually do to increase the abundance and diversity of natural enemies and whether this will have an impact on the pest population and, more importantly, on yield and quality of the crop. Another question is whether biodiversity is always positive for growers or whether there are negative aspects that should be dealt with. These relevant questions are addressed in the present report, the aim of which is to enlarge the current knowledge base on how to improve conditions for natural enemies, so-called habitat manipulation, within annual vegetable crops and perennial apple cropping systems. However, our aim was not to conduct a complete review of all available literature, but instead to select studies that may be of particular value for advisors and growers. We also chose to include the outcomes of a workshop on increasing diversity in apple orchards and interviews with advisors and vegetable growers to investigate the attitude and state of knowledge on habitat manipulation in Sweden today. We focus on natural enemies, arthropod pests and practices applied at field scale, and therefore exclude applications developed for greenhouse crops. Our hope is that advisors and interested growers in particular will find this report relevant and rewarding

    A Comprehensive Survey on Particle Swarm Optimization Algorithm and Its Applications

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    Particle swarm optimization (PSO) is a heuristic global optimization method, proposed originally by Kennedy and Eberhart in 1995. It is now one of the most commonly used optimization techniques. This survey presented a comprehensive investigation of PSO. On one hand, we provided advances with PSO, including its modifications (including quantum-behaved PSO, bare-bones PSO, chaotic PSO, and fuzzy PSO), population topology (as fully connected, von Neumann, ring, star, random, etc.), hybridization (with genetic algorithm, simulated annealing, Tabu search, artificial immune system, ant colony algorithm, artificial bee colony, differential evolution, harmonic search, and biogeography-based optimization), extensions (to multiobjective, constrained, discrete, and binary optimization), theoretical analysis (parameter selection and tuning, and convergence analysis), and parallel implementation (in multicore, multiprocessor, GPU, and cloud computing forms). On the other hand, we offered a survey on applications of PSO to the following eight fields: electrical and electronic engineering, automation control systems, communication theory, operations research, mechanical engineering, fuel and energy, medicine, chemistry, and biology. It is hoped that this survey would be beneficial for the researchers studying PSO algorithms

    Visual Attention in Virtual Reality:(Alternative Format Thesis)

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    A contribution to the understanding of the ethology of the cichlids of Southern Africa

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    Allopatric populations of Pseudocrenilabrus philander were found to differ in male breeding coloration. These colours are described and attention is drawn to the possibility that male coloration might prevent population hybridisation. Behaviour of the allopatric populations was studied in the laboratory. The execution of behaviour patterns of the various populations was found to be indistinguishable, and very similar to that of Haplochromis. Behaviour of P. philander was recorded in three morphologically different natural water bodies. Diurnal activities were found to follow a set rhythm. Though P. philander was shown to have adapted to a variety of habitats they retained their behavioural Components in an unchanged form. Field and laboratory observations are used to propose a behavioural mechanism for the natural regulation of population density. Although aggression between conspecific territorial Sarot herodon mossambicus habituated so that neighbours could live close to one another, it was found that P.philander are intolerant of their neighbours and are consequently forced apart. Though the execution of behaviour patterns was apparently identical for all populations of P. philander, field observations indicated that the frequency of performance differed. An experimental procedure was established to quantitatively compare the behaviour of various populations. As a result of comparative and choice chamber investigations, it is suggested that one of the four populations of P. philander would be unlikely to hybridise with the others if they were to become sympatric. These popUlations would be kept apart because of colour and behavioural differences. Differences of egg-size, fry-size, developmental and interbrood periods were also found, providing further evidence of incipient speciation. Evolutionary divergence of the allopatric populations of P. philander is discussed against a background of geological and geographical evidence. Consideration is given to the role of male coloration, ethological barriers and the importance of ethological differences to taxonomy. Behavioural evidence suggests that P. philander has closer affinities with the haplochromids than was initially realised. It is concluded that the clinal populations of P. philander should not be taxonomically separated, and it is argued that it would be premature to give the Kuruman population an elevated taxonomic status

    Simplifying Cyber Foraging for Mobile Devices

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    Cyber foraging is the transient and opportunistic use of compute servers by mobile devices. The short market life of such devices makes rapid modification of applications for remote execution an important problem. We describe a solution that combines a “little language ” for cyber foraging with an adaptive runtime system. We report results from a user study showing that even novice developers are able to successfully modify large, unfamiliar applications in just a few hours. We also show that the quality of novice-modified and expert-modified applications are comparable in most cases. Categories and Subject Descriptor
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