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Objective To analyze the spatial point pattern distribution characteristics of hemorrhagic fever with renal syndrome (HFRS) in Jingzhou city, Hubei province during the two seasons spring- summer and autumn-winter of 2017, to discuss its high incidence area and reason, and to provide basis for the resource allocation of public health. Methods The analytical data was collected from Infectious Disease Reporting Information System in China, and the spring-summer season was from March to August of 2017, while the autumn-winter was from the September of 2017 to the February of 2018. The Ripley's K-function and kernel density estimation were applied to analyze the spatial point pattern distribution and compare the distribution characteristics of spatial point pattern between the two seasons. Results In 2017, 133 cases of HFRS were reported in Jingzhou city, including the spring- summer and autumn-winter two pick incidences. The strongest aggregation distance was 17.77km in spring-summer season, and 14.40 km in autumn-winter season. The spatial gathering center was located in the north of Jianli County in spring-summer, and it moved to the south of Jiangling County and Shashi District in autumn-winter. Conclusions The key areas for the prevention and control of HFRS in Jingzhou City are Jiangling County, the southern part of Shashi District and the northern part of jianli county. The key groups are the residents of the urban-rural junction in the southern part of Shashi City, residents along the route of large-scale projects, and farmers engaged in agricultural planting or crayfish breeding in the gathering areas.
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ABSTRACT: This study characterized the demography and spatial pattern of a yerba mate (Ilex paraguariensis A.St.-Hil) population covering areas with different use histories (Presence and Absence of Cattle) in a Araucaria Forest. Data collection was performed in three ha, half in each area. The frequency of individuals by height, spatial distribution pattern, diameter distribution (for reproductive individuals) and sexual ratio were evaluated. An inverted "J" pattern predominated, being exclusive to an area with Cattle Presence, a place which presented a lower density of individuals. The predominant spatial distribution pattern was aggregated, and the reproductive individuals have a preferentially random pattern at the shortest distances. Results indicated that cattle presence changes the density of I. paraguariensis individuals and the proportion of individuals in the evaluated demographic classes.
RESUMO: Foi caracterizada a demografia e o padrão espacial de uma população de erva-mate (Ilex paraguariensis A.St.-Hil) abrangendo áreas em diferentes históricos de uso (presença e ausência de gado), em Floresta com Araucárias. A coleta de dados foi realizada em três ha, metade em cada área. Foi avaliada a frequência de indivíduos por classe de altura, padrão de distribuição espacial, distribuição diamétrica (para indivíduos reprodutivos) e razão sexual. O padrão "J" invertido foi predominante, sendo exclusivo para área com presença de gado, local que apresentou uma menor densidade de indivíduos. O padrão de distribuição espacial predominante foi o agregado, sendo que os indivíduos reprodutivos possuem preferencialmente padrão aleatório nas menores distâncias. Os resultados indicam que a presença do gado altera a densidade de I. paraguariensis e a proporção de indivíduos nas classes demográficas avaliadas.
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The objectives of this study were to evaluate the influence of propagules source and the implication of tree size class on the spatial pattern of Xylopia brasiliensis Spreng. individuals growing under the canopy of an experimental plantation of eucalyptus. To this end, all individuals of Xylopia brasiliensis with diameter at soil height (dsh) > 1 cm were mapped in the understory of a 3.16 ha Eucalyptus spp. and Corymbia spp. plantation, located in the municipality of Lavras, SE Brazil. The largest nearby mature tree of X. brasiliensis was considered as the propagules source. Linear regressions were used to assess the influence of the distance of propagules source on the population parameters (density, basal area and height). The spatial pattern of trees was assessed through the Ripley K function. The overall pattern showed that the propagules source distance had strong influence over spatial distribution of trees, mainly the small ones, indicating that the closer the distance from the propagules source, the higher the tree density and the lower the mean tree height. The population showed different spatial distribution patterns according to the spatial scale and diameter class considered. While small trees tended to be aggregated up to around 80 m, the largest individuals were randomly distributed in the area. A plausible explanation for observed patterns might be limited seed rain and intra-population competition.
Os objetivos deste estudo foram avaliar a influência da fonte de propágulo e a implicação de diferentes classes de tamanho sobre o padrão de distribuição espacial de indivíduos de Xylopia brasiliensis Spreng. crescendo sob o dossel de um plantio experimental de eucalipto. Para isso, todos os indivíduos de X. brasiliensis com diâmetro à altura do solo (das) > 1 cm foram mapeados em uma área de 3,16 ha no sub-bosque de um plantio de Eucalyptus ssp. e Corymbia spp., localizado no município de Lavras, MG. O maior e mais próximo indivíduo reprodutivo de X. brasiliensis foi considerado como fonte de propágulos. Foram utilizadas regressões lineares para avaliar a influência da fonte de propágulos sobre parâmetro populacionais (densidade, área basal e altura). O padrão de distribuição espacial das árvores foi avaliado por meio da função K de Ripley. O padrão geral demonstrou que a distância da fonte de propágulo teve forte influência sobre a distribuição espacial das árvores, principalmente as menores, indicando que quanto mais próximo à fonte de propágulos, maior a densidade e menor a altura das árvores. A população demonstrou diferentes distribuições espaciais de acordo com a escala analisada. Enquanto árvores menores tenderam a estar agregadas até uma escala de 80 m, os maiores indivíduos estavam aleatoriamente distribuídos na área. Uma explicação plausível para os padrões observados poderia ser a limitação espacial da chuva de sementes e a competição intraespecífica.
Subject(s)
Ecosystem , Eucalyptus , Xylopia/growth & development , Brazil , Linear Models , Population Density , Tropical ClimateABSTRACT
Objective To detect the spatial point pattern distribution rules of neural tube defects.Methods The kernel density estimation and Ripley's K-function were used to analyze the spatial point pattern of the neural tube birth defects in Heshun county in 1998-2001.Results The kernel density estimation result showed that there was two clusters' distribution in central area and southeastern area respectively.In addition,the result by the Ripley's K-function presented that the location of neural tube birth defects had a significant cluster tendency in the spatial distance from 3.17 to 10.41 kilometers in the investigated area.Conclusion These results can provide an important clue for identifying the relations between environment risk factors and birth defects in this area in the future.