RESUMO
Green vegetation cover fraction (VCF) is an important indicator of vegetation status in ecology and agronomy. Digital image analysis (DIA) has been widely accepted as a new VCF measurement technique. In this study, we present a novel fully automatic threshold segmentation algorithm for VCF measurements, which is named as upper inflection point plus mean gradient magnitude of edge pixels (UIP-MGMEP). The algorithm performs VCF estimation upon the vegetation index Excess Green (EXG). UIP-MGMEP optimizes the EXG threshold by searching the upper inflection point (UIP) of the M-Et curve (mean gradient magnitude of edge pixels (MGMEP) vs. EXG threshold), based on the assumption that EXG variance of the boundary pixels between vegetation and background is larger than the variance of the background. Five typical sample images are used to illustrate how ground complexity reduces the distinctness of the UIP. Three controlled experiments are illustrated to test the robustness of UIP-MGMEP to resolution, exposure, and ground complexity. The results show that UIP-MGMEP is a promising algorithm for automatic VCF estimation upon digital images. Compared to broad-leaved grass, narrow-leaved grass is more sensitive to resolution and exposure. To reduce ground complexity, smaller footprint size while more images to cover the same area may be better than one image with large footprint size. UIP-MGMEP is fully automatic, making it promising for batch processing of VCF measurements that is very difficult in any wide-range field survey in the past. UIP-MGMEP algorithm can only extract green vegetation and is not suitable for non-green (even grayish-green) vegetation, due to the limits of vegetation index EXG. In addition, UIP-MGMEP is not recommended for images with VCF less than 0.5% or greater than 99.5%.
Assuntos
Algoritmos , Monitoramento Ambiental/métodos , Processamento de Imagem Assistida por Computador/métodos , Plantas , Ecologia/métodosRESUMO
A study to investigate the dynamical characteristics of particle matter emissions in a working open yard is conducted in Caofeidian Port of Hebei Province, China. The average diurnal concentrations of the total suspended particulate (TSP) matter and respirable particulate matter (PM10 and PM5) are monitored during the field measurement campaign. Sampling is performed at a regular interval at 8 monitoring stations in the yard with normal industrial activities. The average TSP, PM10 and PM5 concentrations range from 285 to 568, 198 to 423 and 189 to 330 µg.m-3 in the yard, respectively. The linear regression correlation coefficient of TSP/PM10 and TSP/PM5 is 0.95±0.01 and 0.88±0.02, respectively.By using the Spearman correlation method, the wind speed and relative humidity are both weakly correlated with the PM10 and PM5 concentrations according to the measurements. In addition, industrial operation activities, such as vehicular traffic in the yard and the loading time of stackers, are significantly positively correlated with the PM concentration. Using the multivariate regression method, the main parameters influencing the TSP concentration variations are integratedly analysed. The traffic volume is found to be a significant predictor of TSP concentration variation, with the smallest P value (P<0.05).To understand the dynamical characteristics of particle emissions in the yard, the emissions from the truck transports, that is, from unpaved haul roads and from the loading process, are established. Then, the dynamical emission factor (EFD) based on the industrial activities in the yard is proposed. The dynamical emissions average 5.25x105 kg.year-1 and EFD is evaluated to be 0.29 kg.(ton.day)-1 during the measurement period. These outcomes have meaningful implications not only for understanding the dynamical characteristics of particle emissions in the working stockyard but also for implementing effective control measures at appropriate sites in the harbour area.
Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Indústrias , Material Particulado/análise , Poluentes Atmosféricos/química , Umidade , Minerais/química , Veículos Automotores , Tamanho da Partícula , Material Particulado/química , Emissões de Veículos/análise , VentoRESUMO
BACKGROUND: Genetic variations in the engulfment and cell motility 1 (ELMO1) gene have recently been identified to be associated with nephropathy attributed to Type 2 diabetes mellitus (T2DM). Since T2DM-associated complications are proved to be more common among Asians than Western individuals, and Chinese people have a high incidence of diabetic nephropathy (DN), this study sought to analyze the association of ELMO1 gene polymorphisms with DN to probe into the effects of ELMO1 gene on susceptibility of DN in Chinese population. METHODS: We genotyped 6 polymorphism sites of ELMO1 gene in 200 unrelated Chinese subjects (123 T2DM with DN case subjects and 77 T2DM without DN control subjects). Genotyping was detected by a Sequenom MassARRAY genotyping system. RESULTS: The strongest associations in ELMO1 gene with DN occurred at rs741301 [odds ratio (OR) 1.89; p=0.004] and rs10951509 (OR 1.76; p=0.02). Unconditional logistic regression analysis identified that the rs741301 polymorphism (presence of A allele, adjusted OR 3.27; p=0.03) and duration of T2DM (adjusted OR 1.15; p=0.04) were independent predictors for DN. The marker rs741301 located in intron 18 of ELMO1 gene was in strong linkage disequilibrium (LD) with rs11769038 (D'=0.91). Furthermore, haplotype analysis identified that haplotype 1 [CAAAGA] (OR 1.95; p=0.01), haplotype 2 [CAAAGG] (OR 0.50; p=0.01), and haplotype 9 [TGCGGG] (OR 0.17; p=0.007) of ELMO1 were significantly associated with DN. CONCLUSIONS: This study first investigated the association of ELMO1 gene polymorphisms with DN in a Chinese population, supporting its key role as a candidate gene in the susceptibility of DN.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Diabetes Mellitus Tipo 2/complicações , Nefropatias Diabéticas/genética , Polimorfismo de Nucleotídeo Único , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Idoso , Alelos , Estudos de Casos e Controles , China , Estudos de Coortes , Nefropatias Diabéticas/sangue , Nefropatias Diabéticas/metabolismo , Feminino , Frequência do Gene , Estudos de Associação Genética , Predisposição Genética para Doença , Humanos , Íntrons , Desequilíbrio de Ligação , Modelos Logísticos , Masculino , Pessoa de Meia-IdadeRESUMO
A survey of cryptosporidiosis in outpatients and inhabitants in Xuzhou city and 6 rural areas of Jiangsu Province was carried out from 1989 to 1991. Cryptosporidium oocysts (CSO) were found in 97 (1.6%) of 6,221 individuals as a whole, and were detected in 39 (3.3%) of 1,172 outpatients among the examinees. 39 cases were from 31 towns and villages of 8 counties near Xuzhou city. Among the 136 cases, 83 were males and 53 females, of them 89 (65.4%) were infants and young children. The incidence was evidently higher in the group of children under 4 than in that aged 4 to 15 (P < 0.01). Diarrhea, intermittent or persistent, was the main symptom of cryptosporidiosis, being present in 94 (69.1%) of the 136 positive cases, while the other 42 were asymptomatic carriers. The results of routine blood examination and immunoassay performed in a part of the infected children indicated that more than half of them had anemia and lessened cellular immunity. Stool examination of the domestic animals of the affected households showed that a pig and a dog were CSO positive.
Assuntos
Criptosporidiose/epidemiologia , Adolescente , Adulto , Fatores Etários , Estudos de Casos e Controles , Criança , Pré-Escolar , China/epidemiologia , Feminino , Humanos , Incidência , Lactente , Masculino , População Rural , População UrbanaRESUMO
Screening of infants and children under age 15 years for Cryptosporidium oocysts in their stools was carried out in the suburb of Xuzhou City and six rural areas of Jiangsu Province. The infection rate varied from 0.7 to 5.06%. Of the total of 5,089 children examined, 89 (1.75%) were oocyst positive. The incidence was evidently higher in the group of children under age 4 years than it was in children from 4 to 15 years (P less than 0.01). Routine blood examination and immunoassay performed on blood samples from some of the infected children indicated that more than half of them had anemia and lower cellular immunity. Diarrhea was the main symptom of cryptosporidiosis. It was intermittent or persistent and was present in 57 of the 89 children positive for Cryptosporidium oocysts, while the other 32 children were asymptomatic carriers. Examination of stool specimens of adult members and domestic animals of about half of the infected families showed that two mothers, one pig, and one dog were positive for Cryptosporidium oocysts.