466 research outputs found
A high resolution spatial population database of Somalia for disease risk mapping
The article investigates the possibility of creating a data collection system in an unstable environment like Somalia to estimate the incidence of infectious diseases in order to improve the reconstruction of the health sector.Maqaalku wuxuu baarayaa sidii lagu samayn lahaa nidaam lagu ururiyo daatooyinka meel aan xasillooneen sida Soomaaliya, si loo qiyaaso saamaynta cudurrada laysu gudbiyo, loona hagaajiyo qaybta caafimaadka.L'articolo indaga sulla possibilità di creare un sistema di raccolta dati in un contesto instabile come quello somalo per stimare l'incidenza di malattie infettive al fine di una migliore ricostruzione del settore sanitario
Efeito do diluidor e da temperatura de congelação sobre o sêmen congelado de ovino da raça Santa Inês.
Objetivou-se verificar a influência do tipo de diluidor e da temperatura sobre motilidade do sêmen ovino. A coleta do sêmen foi efetuada uma vez por semana em cinco ovinos da raça Santa Inês, após feito um pool dos ejaculados e avaliado quanto ao volume, à motilidade, vigor, concentração e diluído no Leite e Tris. As amostras foram envasadas em palhetas de 0,25 ml e congeladas em três temperaturas (- 79o C, -90o C, -120o C) no equipamento TK 3000. Quando atingida a primeira temperatura, um grupo de palhetas foi transferido para o botijão criogênico e assim sucessivamente, para às demais temperaturas testadas. Após 30 dias, as palhetas foram descongeladas e o sêmen avaliado pelo método CASA. Procedeu-se a ANOVA para testar o efeito da temperatura de congelação sobre os diluidores. Para o diluidor leite, a motilidade progressiva e a percentagem de espermatozóide rápidos diferiu significativamente para temperatura de -79o C em relação às de -90o C e -120o C. No diluidor Tris não houve diferença significativa entre as temperaturas de congelação, entretanto foi significativo e superior ao diluidor a base leite em todas as temperaturas testadas. O diluidor Tris e a temperatura de congelação de -79o C mostraram ser o protocolo de congelação mais apropriado para sêmen de carneiros Santa Inês, entretanto estudos utilizando a inseminação artificial precisam ser conduzidos para validar sua qualidade. Abstract:: This study aimed to verify the influence of the temperature and the extender type on the motility of ram semen. The semen was collected a time per week in five ?Santa Inês? ram, after it was made one pool of the ejaculated and evaluated how much to the volume, motility, vigor, concentration and diluted with Milk and Tris.The samples were stored in straw of 0,25 mL to be frozen in three temperatures (-79°C,-90°C,-120°C) employing the TK 3000 equipment. When reached the first temperature, a group of straws was transferred to the cryogenic container and thus successively, for the the others tested temperatures. After 30 days, the straws had been thawed and the semen evaluated for the CASA method. It was used the ANOVA to test the effect of the temperature of freezing on the extenders. For the Milk, the progressive motility and the fast spermatozoid percentage for the temperature of -79°C differed significantly when compared to the temperatures of -90°C and -120°C. In the extender Tris did not have significant difference between the temperatures of freezing, however it was significant and superior to the extender milk in all tested temperatures. The extender Tris and the freezing temperature of -79°C showed to be the more appropriate freezing protocol for ?Santa Inês? ram semen. However more studies using the artificial insemination need to be lead to validate its quality
Factors associated with the performance and cost-effectiveness of using lymphatic filariasis transmission assessment surveys for monitoring soil-transmitted helminths: a case study in Kenya.
Transmission assessment surveys (TAS) for lymphatic filariasis have been proposed as a platform to assess the impact of mass drug administration (MDA) on soil-transmitted helminths (STHs). This study used computer simulation and field data from pre- and post-MDA settings across Kenya to evaluate the performance and cost-effectiveness of the TAS design for STH assessment compared with alternative survey designs. Variations in the TAS design and different sample sizes and diagnostic methods were also evaluated. The district-level TAS design correctly classified more districts compared with standard STH designs in pre-MDA settings. Aggregating districts into larger evaluation units in a TAS design decreased performance, whereas age group sampled and sample size had minimal impact. The low diagnostic sensitivity of Kato-Katz and mini-FLOTAC methods was found to increase misclassification. We recommend using a district-level TAS among children 8-10 years of age to assess STH but suggest that key consideration is given to evaluation unit size
Spatiotemporal patterns of population in mainland China, 1990 to 2010
According to UN forecasts, global population will increase to over 8 billion by 2025, with much of this anticipated population growth expected in urban areas. In China, the scale of urbanization has, and continues to be, unprecedented in terms of magnitude and rate of change. Since the late 1970s, the percentage of Chinese living in urban areas increased from ~18% to over 50%. To quantify these patterns spatially we use time-invariant or temporally-explicit data, including census data for 1990, 2000, and 2010 in an ensemble prediction model. Resulting multi-temporal, gridded population datasets are unique in terms of granularity and extent, providing fine-scale (~100 m) patterns of population distribution for mainland China. For consistency purposes, the Tibet Autonomous Region, Taiwan, and the islands in the South China Sea were excluded. The statistical model and considerations for temporally comparable maps are described, along with the resulting datasets. Final, mainland China population maps for 1990, 2000, and 2010 are freely available as products from the WorldPop Project website and the WorldPop Dataverse Repository
Modelling changing population distributions: an example of the Kenyan Coast, 1979–2009
Large-scale gridded population datasets are usually produced for the year of input census data using a top-down approach and projected backward and forward in time using national growth rates. Such temporal projections do not include any subnational variation in population distribution trends and ignore changes in geographical covariates such as urban land cover changes. Improved predictions of population distribution changes over time require the use of a limited number of covariates that are time-invariant or temporally explicit. Here we make use of recently released multi-temporal high-resolution global settlement layers, historical census data and latest developments in population distribution modelling methods to reconstruct population distribution changes over 30 years across the Kenyan Coast. We explore the methodological challenges associated with the production of gridded population distribution time-series in data-scarce countries and show that trade-offs have to be found between spatial and temporal resolutions when selecting the best modelling approach. Strategies used to fill data gaps may vary according to the local context and the objective of the study. This work will hopefully serve as a benchmark for future developments of population distribution time-series that are increasingly required for population-at-risk estimations and spatial modelling in various fields
Efeito da concentração espermática sobre sêmen congelado de carneiros da raça Santa Inês.
Objetivou-se verificar o efeito da concentração final dos espermatozóide de ovinos sobre os parâmetros de motilidade do sêmen congelado. Foram coletados seis ejaculados de cinco carneiros Santa Inês, uma vez por semana feito um pool e avaliado o volume, motilidade, vigor, concentração espermática e, fracionado em três alíquotas para testar diluições diferentes (1000x106, 800x106, 600x106 espermatozóides por mL). As amostras foram envasadas em palhetas de 0,25 mL, congeladas no equipamento TK 3000 e conservadas no botijão criogênico. Decorridos 30 dias foram descongeladas e, o sêmen avaliado pelo método CASA. Procedeu-se a ANOVA para testar o resultado da concentração de espermatozóides sobre os parâmetros de motilidade. A concentração de 600 x 106 sptz/ mL para as variáveis percentagens de espermatozóides móveis, motilidade progressiva, percentagem de espermatozóides de velocidade rápida e média mostrou-se superior a de 800 x 106 sptz /mL e 1000 x 106 sptz /ml. Para a variável velocidade média da trajetória do espermatozóide rápido (VAPR) não foi observada diferença significativa entre as concentrações testadas. Neste estudo, a concentração de 600 x 106 sptz/ ml apresentou a melhor preservação dos parâmetros de motilidade após a congelação, tornandose adequada para o uso na inseminação artificial. No entanto necessita-se de mais estudos in vivo para avaliar a eficiência desta técnica
Clade-level Spatial Modelling of HPAI H5N1 Dynamics in the Mekong Region Reveals New Patterns and Associations with Agro-Ecological Factors.
The highly pathogenic avian influenza (HPAI) H5N1 virus has been circulating in Asia since 2003 and diversified into several genetic lineages, or clades. Although the spatial distribution of its outbreaks was extensively studied, differences in clades were never previously taken into account. We developed models to quantify associations over time and space between different HPAI H5N1 viruses from clade 1, 2.3.4 and 2.3.2 and agro-ecological factors. We found that the distribution of clades in the Mekong region from 2004 to 2013 was strongly regionalised, defining specific epidemiological zones, or epizones. Clade 1 became entrenched in the Mekong Delta and was not supplanted by newer clades, in association with a relatively higher presence of domestic ducks. In contrast, two new clades were introduced (2.3.4 and 2.3.2) in northern Viet Nam and were associated with higher chicken density and more intensive chicken production systems. We suggest that differences in poultry production systems in these different epizones may explain these associations, along with differences in introduction pressure from neighbouring countries. The different distribution patterns found at the clade level would not be otherwise apparent through analysis treating all outbreaks equally, which requires improved linking of disease outbreak records and genetic sequence data
Metagenome skimming of insect specimen pools: potential for comparative genomics
Metagenomic analyses are challenging in metazoans, but high-copy number and repeat regions can be assembled from lowcoverage
sequencing by “genome skimming,” which is applied here as a new way of characterizing metagenomes obtained in an ecological or taxonomic context. Illumina shotgun sequencing on two pools of Coleoptera (beetles) of approximately 200 species each were assembled into tens of thousands of scaffolds. Repeated low-coverage sequencing recovered similar scaffold sets consistently, although approximately 70% of scaffolds could not be identified against existing genome databases. Identifiable scaffolds included mitochondrial DNA, conserved sequences with hits to expressed sequence tag and protein databases, and knownrepeatelementsof high and low complexity, includingnumerous copies ofrRNAandhistone genes.Assemblies of histones captured a diversity of gene order and primary sequence in Coleoptera. Scaffolds with similarity to multiple sites in available coleopteran genome sequences for Dendroctonus and Tribolium revealed high specificity of scaffolds to either of these genomes,
in particular for high-copy number repeats. Numerous “clusters” of scaffolds mapped to the same genomic site revealed intraand/or intergenomic variation within a metagenome pool. In addition to effect of taxonomic composition of the metagenomes, the number of mapped scaffolds also revealed structural differences between the two reference genomes, although the significance of this striking finding remains unclear. Finally, apparently exogenous sequences were recovered, including potential food plants, fungal pathogens, and bacterial symbionts. The “metagenome skimming” approach is useful for capturing the genomic diversity of poorly studied, species-rich lineages and opens new prospects in environmental genomic
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