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Search Results: 1 - 10 of 17046 matches for " Spatial Fisher Index "
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Metodología para Estimar un índice Regional de Costo de Vivienda en Chile
PAREDES,DUSAN; AROCA,PATRICIO;
Cuadernos de economía , 2008, DOI: 10.4067/S0717-68212008000100005
Abstract: the aim of this article is to develop a methodology for a spatial or regional cost index of housing that considers spatial differentials across regions. using micro data from the chilean survey casen 2003, it is showed that a spatial or regional housing price index based on the weighted mean or the estimators of hedonic price equations might lead to biased results due to spatial heterogeneity. the potential bias is reduced by matching the houses in a region with a clone in the metropolitan region, according to own and neighbors' characteristics using propensity scores. as a result a very different pattern of spatial cost of housing arises. finally, using a fisher ideal price index, the paper proposes a spatial or regional cost index of housing that shows price differences for homogeneous houses across regions.
Metodología para Estimar un índice Regional de Costo de Vivienda en Chile
DUSAN PAREDES,PATRICIO AROCA
Cuadernos de Economía , 2008,
Abstract: El objetivo de este artículo es proponer una metodología para construir un índice regional de costo de vivienda que tome en consideración la heterogeneidad espacial de éstas. Trabajando con la encuesta CASEN 2003, se muestra que los precios promedios entre regiones así como la estimación de regresiones hedonicas pueden generar resultados sesgados producto de la heterogeneidad espacial. Cuando se homogeiniza la muestra a través de método de pareo "matching", los resultados previos cambian en forma significativa. Finalmente se construye un índice regional de costo de vivienda que captura las diferencias regionales en precios de arriendo de unidades homogéneas. The aim of this article is to develop a methodology for a spatial or regional cost index of housing that considers spatial differentials across regions. Using micro data from the Chilean survey CASEN 2003, it is showed that a spatial or regional housing price index based on the weighted mean or the estimators of hedonic price equations might lead to biased results due to spatial heterogeneity. The potential bias is reduced by matching the houses in a region with a clone in the Metropolitan Region, according to own and neighbors' characteristics using propensity scores. As a result a very different pattern of spatial cost of housing arises. Finally, using a Fisher ideal price index, the paper proposes a spatial or regional cost index of housing that shows price differences for homogeneous houses across regions.
The Geometrycal Interpretation of the Relations between the Laspeyres, Paasche, Fisher and Drobisch Indexes and a New Presentation of the Bortkiewicz Relation
Gabriela OPAI?
Annals of Dun?rea de Jos University. Fascicle I : Economics and Applied Informatics , 2009,
Abstract: The indexes numbers’s rol is to measure and to interpret the averagevariation in time, space or in relation with other systems of reference, in relativesizes, of the levels for the variables who belong to the statistical units from acollectivity. The indexes achieve a statistical analysis of the movement and ofthe change for these phenomenons. Therefore, the indexes are extremelyimportants in to underline the dynamic life which surrounds us.
A Comparison on Biodiversity between Private Conservation and Wildlife Reserve Forests in Riau by using Macro-moths as an Indicator
HARI SUTRISNO
Biodiversitas , 2009,
Abstract: A study on biodiversity of the two forest management types, private conservation forest PT. A and wildlife reserve forest of Suaka Margasatwa Giam Siak Kecil, Riau by using a rapid assessment approach with macro-moths as an indicator was conducted from 23 October to 6 November 2007. Four sample sites were established in Giam Siak Kecil Wildlife Reserve, whereas three sample sites were performed in private conservation forest PT. A. The results show that the diversity indexes based on Fisher’s α of the private forest PT. A was higher than those of wildlife reserve forest Giam Siak Kecil, they were 67.98 and 47.86, respectively. The species composition of the two forests is different, pyralid moths dominate at Giam Siak Kecil. On the contrary, Geometrid moths dominate at private conservation forest PT. A. The results indicated that diversity index and species composition in Giam Siak Kecil is influenced by habitat changes and decrease on floral diversity due to illegal logging. Moreover, a low faunal similarity which is indicated by Jaccard’s index that is only 0.218 showed that the samples represent significant different communities.
Trends in Vegetation Response to Drought in Sudano-Sahelian Part of Northern Nigeria  [PDF]
Blessing Bolarinwa Fabeku, Emmanuel C. Okogbue
Atmospheric and Climate Sciences (ACS) , 2014, DOI: 10.4236/acs.2014.44052
Abstract: This study was carried out to evaluate the drought occurrence and its implication on vegetation cover over the Sudano-Sahelian zone of the Northern part of Nigeria. Monthly mean Rainfall data for the period 40 years (1971-2010) were obtained from Nigeria Meteorological Agency (NIMET) for each of the meteorological stations present and functioning in this region for climatic analysis. Standardized Precipitation Index (SPI) was used to analyze drought occurrence on a time scale of five (5) months that cover the period of raining season over the study area. Also Satellite data over the selected part of the study area for three different epochs, 1986, 2000 and 2005 were used for vegetation response analysis. The SPI values were interpolated using Inverse Distance Weighted (IDW) interpolation technique in ArcGIS 9.3 to generate Drought Spatial Pattern Map for each selected modeled years. The vegetation response indicators used are land cover maps and Greenness Index (GI) maps. Land cover categories were classified into five levels: Dense Vegetation, less dense Vegetation, Settlement/built up, Bare Surface and Water body. The results based on the ground truth (rainfall) data show that many years of drought episode were experienced over the study area. On the other hand, the prime indicators (Land cover and GI maps) used in this study also depicts the changes that took place over the study area in response to this climatic anomaly (drought) and it could be noted that there was dramatic reduction in the occurrence towards the end of the last two decade, 1990-1999, which simply indicated improvement in rainfall even in 2000 and the later years.
Avalia??o de indicador sócio-ambiental utilizado no rastreamento de áreas de transmiss?o de filariose linfática em espa?os urbanos
Braga, Cynthia;Ximenes, Ricardo A. de A.;Albuquerque, Maria de Fátima P. Milit?o de;Souza, Wayner V. de;Miranda, Janaína;Brayner, Fábio;Alves, Luis;Silva, Lania da;Dourado, Inês;
Cadernos de Saúde Pública , 2001, DOI: 10.1590/S0102-311X2001000500021
Abstract: the concept of a "socially organized space" supported by new analytical techniques and mapping of health events has guided innovative methodological developments in public health interventions. this study aimed to evaluate a social/environmental indicator constructed with a scoring methodology to stratify areas in the city of olinda by different levels of risk for bancroftian filariasis transmission. the study mapped areas and the location of sample households and identified all residents ages 5 to 65 years as part of the parasitological survey. among the 3,232 individuals who had blood samples taken, 42 were microfilaremic (1.3% prevalence). global statistical analysis of filarial case distribution has suggested spatial clustering. some 85.7% of positive individuals resided in the two strata with the highest transmission risk. the high sensitivity of the proposed indicator for predicting the places where the vast majority of filariasis cases occurred justifies its use in planning and implementing interventions.
Composición, estructura y diversidad del cerro El águila, Michoacán, México
Zacarias-Eslava, Luis Eduardo;Cornejo-Tenorio, Guadalupe;Cortés-Flores, Jorge;González-Casta?eda, Nahú;Ibarra-Manríquez, Guillermo;
Revista mexicana de biodiversidad , 2011,
Abstract: this study describes composition, structure and diversity of vegetation in the cerro el águila, michoacán. five plant communities were recognized and for each one all woody individuals ≥10 cm dbh were tallied in sixteen 400 m2 circular plots, whereas individuals between 2.5 and 9.9 cm dbh were measured in a 100 m2 circular sub-plot centered within each larger plot. a total of 46 species, 33 genera and 21 families were recorded. the tropical deciduous forest and quercus deserticola forest had low values of mean plant height (< 5 m) and basal area (17.8 and 26 m2/ha, respectively), but these communities showed the higher density. forests dominated by q. rugosa and quercus-pinus had the lowest density but the highest mean height (> 11 m) and basal area (> 40 m2/ha). diversity was greater in the tropical deciduous forest (s= 23 and α= 5.4, respectively) and lower in the oak-pine forest (s= 13 and α= 2.71). all communities displayed different dominant species and high beta diversity. our results suggest that composition and structure could be affected by altitude and human activities. nevertheless, the cerro el águila still has well conservation areas, mainly temperate forests located toward summit zone and we recommend their inclusion in a near future within the state reserve system.
Optimizing Spatial Databases
Anda VELICANU,?tefan OLARU
Informatica Economica Journal , 2010,
Abstract: This paper describes the best way to improve the optimization of spatial databases: through spatial indexes. The most commune and utilized spatial indexes are R-tree and Quadtree and they are presented, analyzed and compared in this paper. Also there are given a few examples of queries that run in Oracle Spatial and are being supported by an R-tree spatial index. Spatial databases offer special features that can be very helpful when needing to represent such data. But in terms of storage and time costs, spatial data can require a lot of resources. This is why optimizing the database is one of the most important aspects when working with large volumes of data.
Composición, estructura y diversidad del cerro El águila, Michoacán, México Composition, structure and diversity of the cerro El águila, Michoacán, Mexico
Luis Eduardo Zacarias-Eslava,Guadalupe Cornejo-Tenorio,Jorge Cortés-Flores,Nahú González-Casta?eda
Revista mexicana de biodiversidad , 2011,
Abstract: Se describe la composición, estructura y diversidad de la vegetación presente en el cerro El águila, Michoacán. Se reconocieron fisonómicamente 5 tipos de vegetación y en cada uno se establecieron 16 parcelas circulares de 400 m2 (3.2 ha) para censar los individuos le osos ≥ 10 cm d.a.p., con una parcela anidada de 100 m2 (0.8 ha) para los individuos entre 2.5 y 9.9 cm d.a.p. El muestreo incluyó 46 especies agrupadas en 33 géneros y 21 familias. Los bosques tropical caducifolio y de Quercus deserticola tuvieron los valores más bajos de altura promedio (< 5 m) y área basal (17.8 y 26 m2/ha, respectivamente), pero una mayor densidad de individuos. En contraste, los bosques de Q. rugosa y de Quercus-Pinus presentaron la menor densidad, pero los valores mayores de altura promedio (> 11 m) y área basal (> 40 m2/ha). La diversidad fue mayor en el bosque tropical caducifolio (S=23 y α =5.4) y menor en el de Quercus-Pinus (S= 13 y α= 2.71). En general, los tipos de vegetación mostraron diferentes especies dominantes y una alta diversidad beta. La composición y estructura de estas comunidades puede asociarse a cambios en altitud y a la perturbación por actividades humanas. No obstante, la zona de estudio aún presenta áreas en buen estado de conservación, particularmente los bosques templados hacia las zonas con mayor altitud, por lo que se sugiere que en un futuro cercano sea incluida dentro de alguna categoría de protección estatal. This study describes composition, structure and diversity of vegetation in the Cerro El águila, Michoacán. Five plant communities were recognized and for each one all woody individuals ≥10 cm DBH were tallied in sixteen 400 m2 circular plots, whereas individuals between 2.5 and 9.9 cm DBH were measured in a 100 m2 circular sub-plot centered within each larger plot. A total of 46 species, 33 genera and 21 families were recorded. The tropical deciduous forest and Quercus deserticola forest had low values of mean plant height (< 5 m) and basal area (17.8 and 26 m2/ha, respectively), but these communities showed the higher density. Forests dominated by Q. rugosa and Quercus-Pinus had the lowest density but the highest mean height (> 11 m) and basal area (> 40 m2/ha). Diversity was greater in the tropical deciduous forest (S= 23 and α= 5.4, respectively) and lower in the oak-pine forest (S= 13 and α= 2.71). All communities displayed different dominant species and high beta diversity. Our results suggest that composition and structure could be affected by altitude and human activities. Nevertheless, the Cerro El águila still has well cons
Correla??o linear e espacial entre o rendimento de gr?os do feijoeiro e a resistência mecanica à penetra??o em um Latossolo Vermelho distrófico
Santos, Paulo Afonso dos;Carvalho, Morel de Passos e;Freddi, On? da Silva;Kitamura, Aline Emy;Freitag, Elisa Eni;Vanzela, Luis Sérgio;
Revista Brasileira de Ciência do Solo , 2005, DOI: 10.1590/S0100-06832005000200014
Abstract: the mechanical penetration resistance of a soil strongly influences plant development since the root growth as well as the crop yield change inversely proportional to its value. the bean grain yield (gy) and the penetration resistance (pr) in a dystrophic red latosol (rhodic ustox) located at the experimental station of the faculdade de engenharia/unesp in ilha solteira county, s?o paulo state, brazil (22 o 23 ' latitude s; 51 o 27 ' longitude w), were analyzed in the crop year 2001/2002. the main objective was to work out guidelines related to the increase of the crop yield in question by studying the spatial and linear correlation between gy and pr. a geostatistical grid to collect soil and plant data was installed in a 5 x 5 m and a 2.5 x 2.5 m spacing. one hundred and twenty sample points were arranged across an area of 1,875 m2. the linear correlation between gy and pr was practically zero since it presented correlation coefficients (r) below 0.20 in function of the studied soil layers. the geostatistical analysis presented a good spatial dependence structure when analyzed for gy as well as pr. however, the joint spatial analysis of the attributes was inconsistent. thus, with the increasing mechanical resistance to penetration in a particular soil region there was sometimes an increase and sometimes a reduction of the grain yield.
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