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Introduction: The prediction of potential fishing areas is considered one of the most immediate and practical approaches in fisheries and is an essential technique for decision-making in managing fishery resources. It helps fishermen reduce their fuel costs and the uncertainty of their fish catches; this technique allows to contribute to national and international food security. In this study, we build different combinations of predictive statistical models such as Generalized Linear Models and Generalized Additive Models. Objective: To predict the spatial distribution of PFZs of the dolphinfish (Coryphaena hippurus L.) in the Colombian Pacific Ocean. Methods: We built different combinations of Generalized Linear Models and Generalized Additive Models to predict the Catch Per Unit Effort of C. hippurus captured from 2002 to 2015 as a function of sea surface temperature, chlorophyll-a concentration, sea level anomaly, and bathymetry. Results: A Generalized Additive Model with Gaussian error distribution obtained the best performance for predicting PFZs for C. hipurus. Model validation was performed by calculating the Root Mean Square Error through a cross-validation approach. The R2 of this model was 50 %, which was considered suitable for the type of data used. January and March were the months with the highest Catch per Unit Effort values, while November and December showed the lower values. Conclusion: The predicted PFZs of C. hippurus with Generalized Additive Models satisfactorily with the results of previous research, suggesting that our model can be explored as a tool for the assessment, decision making, and sustainable use of this species in the Colombian Pacific Ocean.
Introducción: La predicción de zonas potenciales de pesca se considera uno de los enfoques más inmediatos y efectivos en las pesquerías, es una técnica importante para la toma de decisiones en el manejo de los recursos pesqueros. Ayuda a los pescadores a reducir su costo de combustible y también a disminuir la incertidumbre de sus capturas, esta técnica permite contribuir a la seguridad alimentaria nacional e internacional. En este estudio, se construyeron diferentes combinaciones de modelos estadísticos predictivos como modelos lineales generalizados y modelos aditivos generalizados. Objetivo: predecir la distribución espacial de las zonas potenciales de pesca del pez dorado (Coryphaena hippurus L.) en el Pacífico colombiano. Métodos: La variable de respuesta se expresó en escala de captura por unidad de esfuerzo, es decir, el número de individuos de C. hippurus capturados por un número total de anzuelos disponibles entre 2002 y 2015. Temperatura de la superficie del mar, concentración de clorofila, anomalía del nivel del mar y batimetría, se utilizaron como variables explicativas para los meses de estacionalidad de C. hippurus (noviembre - marzo). Resultados: El modelo con mejor rendimiento para la predicción de zonas potenciales de pesca fue un modelo aditivo generalizado con distribución de error gaussiana y función de enlace de registro, que se seleccionó en función del criterio de información de Akaike, el R2 y la desviación explicada. La validación del modelo se realizó calculando el error cuadrático medio a través de un enfoque de validación cruzada. El ajuste de este modelo fue del 50 %, lo que puede considerarse adecuado para el tipo de datos utilizados. Enero y marzo fueron los meses con mayor captura por unidad de esfuerzo y noviembre-diciembre los meses con menor. Conclusión: Las zonas potenciales de pesca previstas coincidieron satisfactoriamente con investigaciones anteriores, lo que sugiere que nuestro modelo es una herramienta poderosa para la evaluación, toma de decisiones y uso sostenible de los recursos pesqueros de C. hippurus en el Pacífico colombiano.
Subject(s)
Animals , Fishing Industry , Forecasting , Colombia , Geographic Information SystemsABSTRACT
Objective To explore the epidemic characteristics and spatial clustering of pulmonary tuberculosis in Wuhan from 2011 to 2019, and to provide a scientific basis for formulating intervention strategies and measures. Methods Descriptive statistical analysis was conducted on the epidemic characteristics of tuberculosis data in Wuhan registered in the national tuberculosis information management system in the last 9 years, and spatial autocorrelation analysis was performed on the incidence of tuberculosis in 155 communities or in the city using Arcgis10.5 software. Results From 2011 to 2019, there were 56,432 cases of tuberculosis reported in Wuhan, and the annual average reported incidence rate of tuberculosis was 59.24/100 000. The overall incidence rate showed a fluctuating downward trend, with an average annual decline rate of 1.99%. The ratio of the number of cases between men and women was 2.35:1, and the incidence rate in males was higher than that in females (χ2=285.36，P0,P<0.001), and the high-high aggregation areas of tuberculosis were mainly distributed in Erqi community, Baibuting community, Liujiaoting community, Yijiadun community, Heping Street, Changqian Street, Tonghu farm, Yuxian Town, Zhifang Town, Wulijie Town, Fenghuang Street, Liji Street, and Daoguanhe Street. Conclusion The overall epidemic situation of pulmonary tuberculosis in Wuhan showed a slow downward trend. The main population and the clustering time of cases were relatively fixed, and the overall epidemic showed a certain spatial clustering. Active screening should be carried out for high-risk populations and high-aggregation areas, and effective prevention and control strategies should be developed based on time and location classification.
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Objective To analyze the endemic sitaution of schistosomiasis based on geographic information system (GIS) in Wuhan City in 2017, so as to provide the reference for further schistosomiasis control activities. Methods According to the data of the annual report on the prevention and control of schistosomiasis in Wuhan City in 2017, the spatial database regarding the endemic situation of schistosomiasis was established and analyzed by ArcMap 10.2. Results The 593 schistosomiasis-endemic villages in Wuhan City were mainly located in the Yangtze River and its major tributaries. Kernel density analysis showed that the endemic villages of three regions with the highest density was located in the west of Caidian District (Zhuru Street), the east of Hannan District (Shamao Street) and the southwest corner of Xinzhou District (Yangluo Street). The sero-positive population was densely distributed in the West of Caidian District (Zhuru Street), which accounted for 34.23% of all seruo-positives in the city. There were 492 farming cattle fenced in Donggan Village in Hongbei Street of Caidian District. A higher density of the area with Oncomelania hupensis snails was located in the southwest region of Caidian District (Xiaosi Street), accounting for 31.22% of the total area with snails. In 2017, the re-emerging area with snails was 36.60 hm2. The high kernel density region with snails was located in Zhuru Street of Caidian District. The region with high density of living snails was located in the central region of Hannan District (Hongbei Production Brigade), the average density of living snails was 0.36 snails/0.1 m2. Conclusions The endemic situation of schistosomiasis is at a low level in Wuhan City, and the spatial distribution is not uniform. In some local areas, the historical endemic situation of schistosomiasis is serious and the high risk factors are more concentrated. It is necessary to strengthen the surveillance of schistosomiasis.
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Objective To analyze the endemic sitaution of schistosomiasis based on geographic information system (GIS) in Wuhan City in 2017, so as to provide the reference for further schistosomiasis control activities. Methods According to the data of the annual report on the prevention and control of schistosomiasis in Wuhan City in 2017, the spatial database regarding the endemic situation of schistosomiasis was established and analyzed by ArcMap 10.2. Results The 593 schistosomiasis-endemic villages in Wuhan City were mainly located in the Yangtze River and its major tributaries. Kernel density analysis showed that the endemic villages of three regions with the highest density was located in the west of Caidian District (Zhuru Street), the east of Hannan District (Shamao Street) and the southwest corner of Xinzhou District (Yangluo Street). The sero-positive population was densely distributed in the West of Caidian District (Zhuru Street), which accounted for 34.23% of all seruo-positives in the city. There were 492 farming cattle fenced in Donggan Village in Hongbei Street of Caidian District. A higher density of the area with Oncomelania hupensis snails was located in the southwest region of Caidian District (Xiaosi Street), accounting for 31.22% of the total area with snails. In 2017, the re-emerging area with snails was 36.60 hm2. The high kernel density region with snails was located in Zhuru Street of Caidian District. The region with high density of living snails was located in the central region of Hannan District (Hongbei Production Brigade), the average density of living snails was 0.36 snails/0.1 m2. Conclusions The endemic situation of schistosomiasis is at a low level in Wuhan City, and the spatial distribution is not uniform. In some local areas, the historical endemic situation of schistosomiasis is serious and the high risk factors are more concentrated. It is necessary to strengthen the surveillance of schistosomiasis.
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Objective: This paper develops a methodology for steady and orderly expansion of the designated medical insurance drugstores. Methods:With the help of grid management ideology, the paper uses ArcGIS and its function modules to define and visualize the scope of the medical insurance drugs service with the guidance of fairness and efficiency through analyzing the basic data including population distribution, the physical distribution of drug-stores and soon. Results:In order to figure out the procedure of the methodology,the key problems were all solved, including defining and visualizing the scope of the medical insurance drugs service area,,checking and ratifying the scope that need to supplement or increase the medical insurance drugstores, making measures for the annual imple-mentation and confirming a selection principle for designated medical insurance drugstores. Conclusion:The Method-ology guided by fairness and efficiency of the medicare designated pharmacy layout planning is practical and feasible, which can probably provide a reference for increasing the designated medical insurance drugstores steadily and orderly.
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Objective:Using an area in east of China as a case,the paper exploit the methodology to define and visualize the scope of the medical insurance pharmacy service through using ArcGIS and its function modules to analy-zing the basic data including this area's population distribution,address of drugstores,administrative districts,road network and soon.Plan A based on the 15-minute walk distance norm for defining the scopes, shows that this area need to increase 548 medical insurances designated drugstore,the effect of which was service area can be increased by 12.36%,service population can be increased by 10.82%, designated drugstore healthy competition rate can be increased by 8.36%;Plan B based on the 10-minute walk distance norm for defining the scopes, displays that this area need to increase 1197 medical insurance designated drugstore, the effect of which was service area can be in-creased by 15.23%,service population can be increased by 20.49%,designated drugstore healthy competition rate can be increased by 19%.
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Objective To predict the colonization risk and potential geographical distribution of Biomphalaria glabrata in the Mainland China based on the past period temperature data.Methods The survival extreme high temperatures and low tem-peratures of B.glabrata eggs,young and adult B.glabrata snails and the average effective accumulated temperature of genera-tion development were determined in laboratory conditions.The temperature data in January and July from 1955 to 2010 were collected from the national meteorological monitoring sites in the southern part of China,including Chongqing,Zhejiang,Yun-nan,Sichuan,Jiangxi,Hunan,Hainan,Guizhou,Guangdong,Guangxi and Fujian provinces(11 provinces).A database of ambient temperature related to B.glabrata was established based on the Geographic Information System(GIS).The colonization risk and potential geographical distribution of B.glabrata in the southern part of China were analyzed and predicted by ArcGIS 10.1 software.Results The half lethal low temperatures of B.glabrata eggs,young and adult B.glabrata snails were 6.80,6.34℃ and 6.60℃ respectively;the half lethal high temperatures of B.glabrata eggs,young and adult B.glabrata snails were 35.99,33.59℃ and 32.20℃,respectively.The developmental threshold temperature was 7.16℃;the average effective accumu-lated temperature of generation development was(1 970.07 ± 455.10)days-degree.The GIS overlay analysis of the half lethal low and high temperatures of B.glabrata showed that the local temperature conditions in all Hainan and part regions in Yunnan,Guangxi,Guangdong and Fujian were conformed to the survival temperature of B.glabrata snails.The regions,where the aver-age effective accumulated temperature was more than the average effective accumulated temperature of generation development of B.glabrata,were Guangdong and Hainan,and part regions of other 9 provinces.The overlay analysis of GIS maps of the sur-vival extreme high temperatures and low temperatures of B.glabrata with the GIS map of the average effective accumulated tem-perature of generation development in 2010 showed that the whole region of Hainan and part regions of Guangdong,Guangxi,Yunnan and Fujian were potential geographical distribution regions of colonization risk of B.glabrata.The overlay analysis of GIS maps of the survival extreme high temperatures and low temperatures of B.glabrata with the GIS map of the average effective accumulated temperature of generation development from 1955 to 2010 showed that the potential geographical distribution re-gions of B.glabrata was expanding from the whole region of Hainan and part regions of Guangdong in 1955 to the whole region of Hainan and part regions of Guangdong,Guangxi,Yunnan and Fujian in 2010.Conclusions If B.glabrata snails were intro-duced into the Mainland China,the potential geographical distribution regions would be the whole region of Hainan and part re-gions of Guangdong,Guangxi and Yunnan.The changes of risk range and risk intensity present the trends of expanding and in-creasing from the south to the north gradually.
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This study focused on assessing the prevalence, geospatial distribution and risk factors for bovine cysticercosis in cattle from the state of Rondônia, Brazil, through the years 2012 to 2015. The prevalence established was 0.014% (95% C.I. 0.013-0.014), with a higher detection of unviable cysticerci (84.80%). The municipalities of Itapuã do Oeste, Candeias do Jamari, Nova Brasilândia D'Oeste, Pimenteiras do Oeste, Porto Velho, Nova Mamoré, Urupá and Guajará-Mirim had higher risk (OR>1; p<0.05) for cysticercosis occurrence compared with the municipality of Castanheiras (OR=1). The Administrative Regions of Porto Velho, Guajará-Mirim, Colorado D'Oeste, Cacoal, Ji-Paraná had higher risk (OR>1; p<0.05) for cysticercosis occurrence in the slaughtered animals than those reared in Ariquemes Administrative Region (OR=1). Some variables such as human population density (OR=2.15; 2.15-2.16), percentage of urban houses with inappropriate sewage system (OR=1.91, 1.91-.1.92) and percentage of inappropriate rural sewage system (OR=1.14, 1.14-1.14) were significantly associated (p<0.05) with the occurrence of bovine cysticercosis. In conclusion, the prevalence of bovine cysticercosis in the state of Rondônia was 0.014% (95% C.I. 0.013-0.014) and higher-risk areas were identified, providing useful information to Official Sanitary Inspection System in order to improve cysticercosis detection. Also, human population density and the lack of appropriate sewage system in urban and rural areas are closely related to bovine cysticercosis occurrence in this state.(AU)
Este estudo objetivou avaliar a prevalência, distribuição espacial e fatores de risco para a ocorrência de cisticercose bovina em animais abatidos oriundos do Estado de Rondônia, Brasil, entre os anos de 2012 a 2015. A prevalência observada foi de 0,014% (I.C. 95% 0,013-0,014), com maior detecção de cisticercos inviáveis (84,80%). Os municípios de Itapuã do Oeste, Candeias do Jamari, Nova Brasilândia D'Oeste, Pimenteiras do Oeste, Porto Velho, Nova Mamoré, Urupá e Guajará-Mirim apresentaram maior risco (OR>1; p<0.05) para a ocorrência da enfermidade quando comparadas ao município de Castanheiras (OR=1). As Regiões Administrativas de Porto Velho, Guajará-Mirim, Colorado D'Oeste, Cacoal, Ji-Paraná, respectivamente, apresentaram maior risco (OR>1; p<0.05) para a ocorrência de cisticercose nos bovinos abatidos comparadas à Região Administrativa de Ariquemes (OR=1). Algumas variáveis como a densidade populacional humana (OR=2,15; 2,15-2,16), percentual de domicílios urbanos com saneamento inadequado (OR=1,91, 1,91-1,92) e percentual de saneamento rural inadequado (OR=1,14, 1,14-1,14) apresentaram-se como fatores de risco significativos (p<0.05) para a ocorrência de cisticercose bovina. Conclui-se que a prevalência de cisticercose bovina no Estado de Rondônia foi 0,014% (I.C. 95% 0,013-0,014) e que áreas de maior ocorrência puderam ser identificadas, fornecendo informações a serem utilizadas pelo Serviço de Inspeção Federal para melhorar a detecção dos casos. Ainda, a densidade da população humana e a deficiência de sistemas de tratamento de esgotos urbanos e rurais estão intimamente relacionadas com a ocorrência da cisticercose bovina neste estado.(AU)
Subject(s)
Animals , Cattle , Cysticercosis/epidemiology , Disease Outbreaks/veterinary , Taenia saginata , Brazil , Zoonoses , Risk Factors , Geographic Information SystemsABSTRACT
At the urgent practical issue of resource protection and artificial cultivation area selection of Dioscorea nipponica, the dominant environmental factors affecting the distribution of D. nipponicain Jilin province were selected by field investigation and using the maximum information entropy model and geographic information technology. MaxEnt model study found that the standard deviation of seasonal variation of temperature, precipitation in October and other six environmental factors on the growth of D. nipponica are the greatest impacting factors. The range of suitability for the growth of D. nipponica was 4.612 08×10-6-0.544 31, and the regionalization study was divided into four parts: high fitness area, middle fitness area, low fitness area and unfavorable area. The high fitness area is concentrated in the central and southern areas of Jilin Province, using ArcGIS statistical environment factors in the appropriate area of the numerical situation. The results showed that the regionalization study of D. nipponica was basically the same as the actual situation. It is clear that the natural environment suitable for the growth of D. nipponica is also the basis for the protection of the resources and the selection of cultivated area.
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Objective To construct the Oncomelania hupensis snail monitoring system based on the Baidu Map. Methods The environmental basic information about historical snail environment and existing snail environment,etc. was collected with the monitoring data about different kinds of O. hupensis snails,and then the O. hupensis snail monitoring system was built. Geo-graphic Information System(GIS)and the electronic fence technology and Application Program Interface(API)were applied to set up the electronic fence of the snail surveillance environments,and the electronic fence was connected to the database of the snail surveillance. Results The O. hupensis snail monitoring system based on the Baidu Map were built up,including three modules of O. hupensis Snail Monitoring Environmental Database,Dynamic Monitoring Platform and Electronic Map. The infor-mation about monitoring O. hupensis snails could be obtained through the computer and smartphone simultaneously. Conclu-sion The O. hupensis snail monitoring system,which is based on Baidu Map,is a visible platform to follow the process of snail-searching and molluscaciding.
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Objective To study the application of Geographic Information System(GIS)electronic fence technique in Onco-melania hupensis snail monitoring. Methods The electronic fence was set around the history and existing snail environments in the electronic map,the information about snail monitoring and controlling was linked to the electronic fence,and the snail moni-toring information system was established on these bases. The monitoring information was input through the computer and smart phone. Results The electronic fence around the history and existing snail environments was set in the electronic map(Baidu map),and the snail monitoring information system and smart phone APP were established. The monitoring information was input and upload real-time,and the snail monitoring information was demonstrated in real time on Baidu map. Conclusion By using the electronic fence technology based on GIS,the unique"environment electronic archives"for each snail monitoring environ-ment can be established in the electronic map,and real-time,dynamic monitoring and visual management can be realized.
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Objective To survey the 238U radioactivity level in the surface soil in the Beijing-Tianjin-Hebei Border (BTHB) region,and to prepare a high resolution distribution map of 238U activity concentrations.Methods The soil samples were collected in a grid (10 km × 10 km).The activity concentrations of 238U in soil samples were measured by using HPGe γ spectrometry.The distribution of the activity concentrations of 238U in soil samples was mapped by the aid of MAPGIS software.Results In total,416 samples were collected and measured.The activity concentrations of 238U were in the range of 0.1-106.0 Bq/kg,with an average of 34.7 Bq/kg.The 238U activity concentration distribution map showed that 238U activity concentration was in the range of 15-55 Bq/kg mostly on the surface soil in the BTHB region.Conclusions The map of 238U activity concentration shows the distribution of 238U activity concentration in the BTHB region.It is of importance to map the distribution of 238U activity concentration in the BTHB region,by converting a huge amount of data into the simple and intuitive graphics,and for evaluating the regional environmental radioactivity and studying the radioactive substance migration within the locality.
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Fasciolosis affects different ruminant species and leads to great economic losses for cattle farmers worldwide. Thus, the current study aimed to evaluate bovine fasciolosis prevalence in the state of Espírito Santo, Brazil, using slaughter maps provided by slaughterhouses and verifying the origin of cattle. : A map was created based on analysis of epidemiological data. The ArcGIS/ArcINFO 10.1 software was employed in order to elaborate updated bioclimatic maps that displayed the fasciolosis prevalence within the state per city between 2009 and 2011.
Subject(s)
Animals , Abattoirs , Fasciola hepatica/pathogenicity , Geography/methods , Maps as Topic , Parasites/parasitologyABSTRACT
Fasciolosis affects different ruminant species and leads to great economic losses for cattle farmers worldwide. Thus, the current study aimed to evaluate bovine fasciolosis prevalence in the state of Espírito Santo, Brazil, using slaughter maps provided by slaughterhouses and verifying the origin of cattle. : A map was created based on analysis of epidemiological data. The ArcGIS/ArcINFO 10.1 software was employed in order to elaborate updated bioclimatic maps that displayed the fasciolosis prevalence within the state per city between 2009 and 2011.
Subject(s)
Animals , Fasciola hepatica/pathogenicity , Geography/methods , Maps as Topic , Abattoirs , Parasites/parasitologyABSTRACT
Creating precise climatic maps (temperature and precipitation map especially) on small areas such as drainage basins or landform units is always very useful for ecology of plants, distribution of vegetation and also different types of agricultural land. The geographic information system (GIS) analysis of several key-factors (aspect and slope of terrain, insolation degree, thermal gradient, geology and structure of landforms) offers the necessary tools to operate with in order to create an accurate climatic map. This method was applied in order to create a map showing the distribution of temperatures in the Olanesti drainages basin, a 235 km2 area located at middle latitude, in Romania. After creating the DEM, aspect and slope of the terrain, reclassifying categories and calculating the thermal gradient, a map showing the distribution of the annual mean temperature is obtained. Other climatic parameters could be calculated for small areas too, with precise results. These demonstrate that not only elevation and mathematical location of an area are important factors in the distribution of temperature, but also the aspect, the gradient, the insolation, the type of rock and the structure.
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The limit between low morphological units is quite difficult to be established due to the fact that the lithological, elevation and/or structure differences are hardly visible. Thus, the contact between piedmont and plain units is represented, in many cases, by areas where limits are hard to be drawn. In order to establish the way geographic information system (GIS) may contribute to the determination of the aforementioned limits, we used the situation of the limit between the Getic Piedmont and the Romanian plain and compared the obtained results to examples from other areas with different formation and evolution conditions. Presently, the Getic Piedmont undergoes a modelling process as valleys widen, torrential enlargements laterally advance, and slope denudation develop, which make difficult to establish a clear southern limit. The fan texture of the valleys, their age, the flowing direction, as well as the differences of altitude, lithology, and structure disposal represent the main elements when establishing limits even in the case of GIS analysis. The drawing of thematic layers rendering elements such as hydrographic system, hypsometry, DEM on a traditional cartographic support, orthophotoplans, satellite images, for a better interpretation of the geomorphologic aspects allow a more objective attempt of reconstructing the morphological limits.
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<b>Background:</b> When analyzing regional disparities in healthcare resources, hospital accessibility is given little consideration. We surveyed accessibility from residential districts to medical institutions using GIS (Geographic Information System) and estimated Gini coefficient for each hospital distribution.<br><b>Methods:</b> The subjects were 2,688 census mesh blocks ( “<i>Cho</i>-<i>cho</i>-<i>aza</i>” ) and 109 hospitals in Tochigi prefecture. The number of hospitals located within the road distances of 5 km, 10 km and 15 km from the geometrical center of each block was calculated using GIS. The Gini coefficient of each hospital per 100 residents was calculated among the regions located within 5 km, 10 km and 15 km from the geometrical center of the census mesh block.<br><b>Results:</b> The population of each block was 748±1,067 (mean±SD), and the road distance to the nearest hospital from the center of each block was 4.3±4.5 km. The number of census mesh blocks with distances from the center of each block to the nearest hospital within 5 km, 5-10 km, 10-15 km and more than 15 km were 1909 (71.0%), 561 (20.9%), 139 (5.2%) and 79 (2.9%) respectively. The number of hospitals located within 5 km, 10 km and 15 km were 3.3±4.7, 8.3±8.6 and 14.4±11.4. Gini coefficients were 0.65, 0.52 and 0.43.<br><b>Conclusion:</b> When analyzing regional disparities in healthcare resources, it is necessary to take into account not only the number of physicians and beds, but also accessibility. Gini coefficient is useful to estimate geographical distributions, and can be used as an indicator for improvement projects for hospitals.
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Previous studies have been able to successfully detect changes in gently-sloping forested areas with low-diversity and homogeneous vegetation cover, using medium-resolution satellite data such as landsat. The aim of the present study is to examine the capacity of multi-temporal landsat data to identify changes in forested areas with mixed vegetation and generally located on steep slopes or non-uniform topography. landsat thematic mapper (TM)and landsat enhanced thematic mapper plus (ETM+) data for the years 1987-2000 was used to detect changes within a 19,500 ha forested area in the Western Black sea region of Turkey. The data comply with the forest cover type maps previously created for forest management plans of the research area. The methods used to detect changes were: postclassification comparison, image differencing, image rationing and NDVI (Normalized Difference Vegetation Index) differencing methods. Following the supervised classification process, error matrices were used to evaluate the accuracy of classified images obtained. The overall accuracy has been calculated as 87.59% for 1987 image and as 91.81% for 2000 image. General kappa statistics have been calculated as 0.8543 and 0.9038 for 1987 and 2000, respectively. The changes identified via the post-classification comparison method were compared with other change detetion methods. Maximum coherence was found to be 74.95% at 4/3 band rate. The NDVI difference and 3rd band difference methods achieved the same coherence with slight variations. The results suggest that landsat satellite data accurately conveys the temporal changes which occur on steeply-sloping forested areas with a mixed structure, providing a limited amount of detail but with a high level of accuracy. Moreover, it has been decided that the post-classification comparison method can meet the needs of forestry activities better than other methods as it provides information about the direction of these changes.
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Objective To understand the epidemiologic trend and characteristics of the distribution of schistosomiasis in Yunnan Province, China. Methods The data of two sampling surveys on schistosomiasis in Yunnan in 1995 and 2003 were collected, and the database of GIS was set up. The spatial status of rates of human infection and cattle infection were analyzed by using the GIS software, ArcView 3.2, contours method. The relationships between rates of human infection and cattle infection in 1995 and 2003 were analyzed with SPSS statistical software. Results The high-risk areas of schistosomiasis in Yunnan were Dali City, Yongsheng, Heqing, Eryuan, Weishan and Nanjian counties, and those areas contained different infection grades which were intertwine. The rate of human infection was descendent and the distribution of high-risk areas of schistosomiasis was decreasing. The infection rate of cattle was higher than before in the south of epidemic areas in Yunnan. Those epidemic areas of schistosomiasis could be identified as three spatial distributions. Conclusions The control and prevention of schistosomiasis in Yunnan should be focus on Dali City, Eryuan, Weishan, Yongsheng, Heqing and Nanjian counties, and the key is synchronistical chemotherapy in human and cattle.