109 research outputs found

    Analysis of Different Types of Regret in Continuous Noisy Optimization

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    The performance measure of an algorithm is a crucial part of its analysis. The performance can be determined by the study on the convergence rate of the algorithm in question. It is necessary to study some (hopefully convergent) sequence that will measure how "good" is the approximated optimum compared to the real optimum. The concept of Regret is widely used in the bandit literature for assessing the performance of an algorithm. The same concept is also used in the framework of optimization algorithms, sometimes under other names or without a specific name. And the numerical evaluation of convergence rate of noisy algorithms often involves approximations of regrets. We discuss here two types of approximations of Simple Regret used in practice for the evaluation of algorithms for noisy optimization. We use specific algorithms of different nature and the noisy sphere function to show the following results. The approximation of Simple Regret, termed here Approximate Simple Regret, used in some optimization testbeds, fails to estimate the Simple Regret convergence rate. We also discuss a recent new approximation of Simple Regret, that we term Robust Simple Regret, and show its advantages and disadvantages.Comment: Genetic and Evolutionary Computation Conference 2016, Jul 2016, Denver, United States. 201

    Current diversity of Phytophthora infestans infecting cultivated potato in the Peruvian Andes

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    Late blight caused by P. infestans is the most devastating disease of potato worldwide. To understand the current P. infestans population structure in the Peruvian Andes, 701 single-lesion samples were collected from cultivated potato in different agroecological zones at 2016-2017. Genetic diversity was analyzed using the 12-plex SSR markers kit and mtADN. Phenotypic diversity was characterized for mating type, metalaxyl resistance and virulence. SSR analysis showed that population consists of EC-1 and PE-3 clonal lineages variants, that have the mtADN IIa and Ia, respectively. All isolates were A1 mating type. 94% of the EC-1 variant isolates were resistant to metalaxil, whereas the sensitive proportion (47%) in the PE-3 variants was bigger than the resistant (35%). Furthermore, virulence assays detected 41 complex physiological races from 142 selected isolates, the most frequent physiological race was 1,3,4,7,10,11 in both EC-1 and PE-3 variants. Phylogenetic analysis evidenced that isolates share identical SSR genotypes and physiological races in distant regions, that suggests that migration could have occurred. Additionally, no detection of A2 mating type indicate that population reproduction must be asexual. EC-1 clonal lineage continues to dominate across the Peruvian Andes, since 91% of the isolates were variants of this clonal lineage. The US-1 clonal lineage reported at 2001, appears to be displaced as it was no longer detected infecting cultivated potato

    The making of the oral microbiome in Agta hunter–gatherers

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    Ecological and genetic factors have influenced the composition of the human microbiome during our evolutionary history. We analysed the oral microbiota of the Agta, a hunter–gatherer population where some members have adopted an agricultural diet. We show that age is the strongest factor modulating the microbiome, probably through immunosenescence since we identified an increase in the number of species classified as pathogens with age. We also characterised biological and cultural processes generating sexual dimorphism in the oral microbiome. A small subset of oral bacteria is influenced by the host genome, linking host collagen genes to bacterial biofilm formation. Our data also suggest that shifting from a fish/meat diet to a rice-rich diet transforms their microbiome, mirroring the Neolithic transition. All of these factors have implications in the epidemiology of oral diseases. Thus, the human oral microbiome is multifactorial and shaped by various ecological and social factors that modify the oral environment

    Agta hunter–gatherer oral microbiomes are shaped by contact network structure

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    Here we investigate the effects of extensive sociality and mobility on the oral microbiome of 138 Agta hunter–gatherers from the Philippines. Our comparisons of microbiome composition showed that the Agta are more similar to Central African BaYaka hunter–gatherers than to neighbouring farmers. We also defined the Agta social microbiome as a set of 137 oral bacteria (only 7% of 1980 amplicon sequence variants) significantly influenced by social contact (quantified through wireless sensors of short-range interactions). We show that large interaction networks including strong links between close kin, spouses and even unrelated friends can significantly predict bacterial transmission networks across Agta camps. Finally, we show that more central individuals to social networks are also bacterial supersharers. We conclude that hunter–gatherer social microbiomes are predominantly pathogenic and were shaped by evolutionary tradeoffs between extensive sociality and disease spread

    Interventions for the control of Aedes aegypti in Latin America and the Caribbean: systematic review and meta-analysis

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    Objective: To determine the effectiveness and degree of implementation of interventions for the control of Aedes aegypti in Latin America and the Caribbean (LAC) as reported in scientific literature. Methods: We searched MEDLINE, EMBASE, CENTRAL, SOCINDEX, and LILACS, for experimental and observational studies, economic assessments and qualitative experiences carried out in LAC from 2000 to 2016. We assessed incidence and morbimortality of Aedes aegypti-related diseases and entomological indices: Breteau (containers), House, and Pupae per Person. We used GRADE methodology for assessing quality of evidence. Results: Of 1826 records retrieved, 75 were included and 9 cluster randomised clinical trials could be meta-analysed. We did not identify any intervention supported by a high certainty of evidence. In consistency with qualitative evidence, health education and community engagement probably reduces the entomological indices, as do the use of insecticide-treated materials, indoor residual spraying and the management of containers. There is low certainty of evidence supporting the use of ovitraps or larvitraps, and the integrated epidemiological surveillance strategy to improve indices and reduce the incidence of dengue. The reported degree of implementation of these vector control interventions was variable and most did not extend to whole cities and were not sustained beyond 2 years. Conclusions: We found a general lack of evidence on effectiveness of vector control in the region, despite a few interventions that showed moderate to low certainty of evidence. It is important to engage and educate the community, apart from achieving the implementation of integrated actions between the health and other sectors at national and regional level.Fil: Bardach, Ariel Esteban. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Parque Centenario. Centro de Investigaciones en EpidemiologĂ­a y Salud PĂșblica. Instituto de Efectividad ClĂ­nica y Sanitaria. Centro de Investigaciones en EpidemiologĂ­a y Salud PĂșblica; ArgentinaFil: GarcĂ­a Perdomo, Herney AndrĂ©s. Universidad del Valle; ColombiaFil: Alcaraz, Andrea. Instituto de Efectividad ClĂ­nica y Sanitaria; ArgentinaFil: Tapia LĂłpez, Elena. Instituto de Efectividad ClĂ­nica y Sanitaria; ArgentinaFil: Ruano Gandara, Ruth Amanda. Instituto de Efectividad ClĂ­nica y Sanitaria; ArgentinaFil: Ruvinsky, Silvina. Gobierno de la Ciudad de Buenos Aires. Hospital de PediatrĂ­a "Juan P. Garrahan"; ArgentinaFil: Ciapponi, AgustĂ­n. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Parque Centenario. Centro de Investigaciones en EpidemiologĂ­a y Salud PĂșblica. Instituto de Efectividad ClĂ­nica y Sanitaria. Centro de Investigaciones en EpidemiologĂ­a y Salud PĂșblica; Argentin

    The impact of dengue illness on social distancing and caregiving behavior

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    Background Human mobility among residential locations can drive dengue virus (DENV) transmission dynamics. Recently, it was shown that individuals with symptomatic DENV infection exhibit significant changes in their mobility patterns, spending more time at home during illness. This change in mobility is predicted to increase the risk of acquiring infection for those living with or visiting the ill individual. It has yet to be considered, however, whether social contacts are also changing their mobility, either by socially distancing themselves from the infectious individual or increasing contact to help care for them. Social, or physical, distancing and caregiving could have diverse yet important impacts on DENV transmission dynamics; therefore, it is necessary to better understand the nature and frequency of these behaviors including their effect on mobility. Methodology and principal findings Through community-based febrile illness surveillance and RT-PCR infection confirmation, 67 DENV positive (DENV+) residents were identified in the city of Iquitos, Peru. Using retrospective interviews, data were collected on visitors and home-based care received during the illness. While 15% of participants lost visitors during their illness, 22% gained visitors; overall, 32% of all individuals (particularly females) received visitors while symptomatic. Caregiving was common (90%), particularly caring by housemates (91%) and caring for children (98%). Twenty-eight percent of caregivers changed their behavior enough to have their work (and, likely, mobility patterns) affected. This was significantly more likely when caring for individuals with low “health-related quality of well-being” during illness (Fisher’s Exact, p = 0.01). Conclusions/Significance Our study demonstrates that social contacts of individuals with dengue modify their patterns of visitation and caregiving. The observed mobility changes could impact a susceptible individual’s exposure to virus or a presymptomatic/clinically inapparent individual’s contribution to onward transmission. Accounting for changes in social contact mobility is imperative in order to get a more accurate understanding of DENV transmission

    Co-encapsulation of human serum albumin and superparamagnetic iron oxide in PLGA nanoparticles: Part I. Effect of process variables on the mean size

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    PLGA (poly d,l-lactic-co-glycolic acid) nanoparticles (NPs) encapsulating magnetite nanoparticles (MNPs) along with a model drug human serum albumin (HSA) were prepared by double emulsion solvent evaporation method. This Part I will focus on size and size distribution of prepared NPs, whereas encapsulation efficiency will be discussed in Part II. It was found that mean hydrodynamic particle size was influenced by five important process variables. To explore their effects, a five-factorial, three-level experimental design and statistical analysis were carried out using STATISTICA¼ software. Effect of process variables on the mean size of nanoparticles was investigated and finally conditions to minimize size of NPs were proposed. GAMSℱ/MINOS software was used for optimization. The mean hydrodynamic size of nanoparticles ranged from 115 to 329 nm depending on the process conditions. Smallest possible mean particle size can be achieved by using low polymer concentration and high dispersion energy (enough sonication time) along with small aqueous/organic volume ratio

    Agta hunter–gatherer oral microbiomes are shaped by contact network structure

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    Here we investigate the effects of extensive sociality and mobility on the oral microbiome of 138 Agta hunter–gatherers from the Philippines. Our comparisons of microbiome composition showed that the Agta are more similar to Central African BaYaka hunter–gatherers than to neighbouring farmers. We also defined the Agta social microbiome as a set of 137 oral bacteria (only 7% of 1980 amplicon sequence variants) significantly influenced by social contact (quantified through wireless sensors of short-range interactions). We show that large interaction networks including strong links between close kin, spouses and even unrelated friends can significantly predict bacterial transmission networks across Agta camps. Finally, we show that more central individuals to social networks are also bacterial supersharers. We conclude that hunter–gatherer social microbiomes are predominantly pathogenic and were shaped by evolutionary tradeoffs between extensive sociality and disease spread
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