RESUMO

We introduce a model that can be used for the description of the distribution of species when there is scarcity of data, based on our previous work (Ballesteros et al. J Math Biol 85(4):31, 2022). We address challenges in modeling species that are seldom observed in nature, for example species included in The International Union for Conservation of Nature's Red List of Threatened Species (IUCN 2023). We introduce a general method and test it using a case study of a near threatened species of amphibians called Plectrohyla Guatemalensis (see IUCN 2023) in a region of the UNESCO natural reserve "Tacaná Volcano", in the border between Mexico and Guatemala. Since threatened species are difficult to find in nature, collected data can be extremely reduced. This produces a mathematical problem in the sense that the usual modeling in terms of Markov random fields representing individuals associated to locations in a grid generates artificial clusters around the observations, which are unreasonable. We propose a different approach in which our random variables describe yearly averages of expectation values of the number of individuals instead of individuals (and they take values on a compact interval). Our approach takes advantage of intuitive insights from environmental properties: in nature individuals are attracted or repulsed by specific features (Ballesteros et al. J Math Biol 85(4):31, 2022). Drawing inspiration from quantum mechanics, we incorporate quantum Hamiltonians into classical statistical mechanics (i.e. Gibbs measures or Markov random fields). The equilibrium between spreading and attractive/repulsive forces governs the behavior of the species, expressed through a global control problem involving an energy operator.

Assuntos

RESUMO

BACKGROUND: Multiple sclerosis (MS) is an important cause of acquired neurological disability in young adults, characterized by multicentric inflammation, demyelination, and axonal damage. OBJECTIVE: The objective is to investigate white matter (WM) damage progression in a Brazilian MS patient cohort, using diffusion tensor imaging (DTI) post-processed by tract-based spatial statistics (TBSS). METHODS: DTI scans were acquired from 76 MS patients and 37 sex-and-age matched controls. Patients were divided into three groups based on disease duration. DTI was performed along 30 non-collinear directions by using a 1.5T imager. For TBSS analysis, the WM skeleton was created, and a 5000 permutation-based inference with a threshold of p < .05 was used, to enable the identification of abnormalities in fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity (AD). RESULTS: Decreased FA and increased RD, MD, and AD were seen in patients compared to controls and a decreased FA and increased MD and RD were seen, predominantly after the first 5 years of disease, when compared between groups. CONCLUSION: Progressive WM deterioration is seen over time with a more prominent pattern after 5 years of disease onset, providing evidence that the early years might be a window to optimize treatment and prevent disability.

Assuntos

RESUMO

The environment is vital to the agricultural sector since it can cause adversities throughout the entire productive chain. This study evaluated the geographical distribution of zebu breeds in Brazil and correlated their occurrence with environmental variables and the human development index. Herds of purebred zebu cattle (Bos indicus) in Brazil were classified as beef, dairy, and dual-purpose breeds, and all breeds were spatialized in the ArcGIS program. Environmental (precipitation, temperature, relative humidity index) and the human development index (HDI) were examined. We conducted regression and logistic analyses. Zebu cattle showed a lower distribution in the Northeastern states compared to other locations, possibly due to harsh weather conditions, namely long periods of high temperatures and lower precipitation, directly affecting local livestock. Beef breeds were evenly spread throughout the country in regions influenced by environmental variables of higher precipitation, normalized difference vegetation index (NDVI), temperature, relative humidity (RH), and temperature humidity index (THI), as well as properties without smallholder farmers and rivers and streams with riparian vegetation. The regions for dual-purpose and dairy breeds were predominantly cultivated with cutting forages (e.g., sugarcane - Saccharum officinarum), with the integration of crops, livestock and/or forestry (i.e., combining different activities in the same area) and areas with a rotational grazing system (i.e., grazing management), indicating a higher occupation in fertile lands. The Gir breed, the only dairy breed evaluated in this study, was seen in establishments with smallholder farmers, characterized by small to medium farms, and in regions at higher altitudes.

Assuntos

RESUMO

RESUMO O Município do Rio de Janeiro (MRJ) estava entre as cidades com altas taxas de mortalidade ao longo da pandemia de Covid-19. Neste estudo, analisamos as taxas de incidência, de mortalidade e letalidade por Covid-19 nas áreas com predominância de Aglomerados Subnormais (ASN). Foram considerados todos os 36 bairros da Sub-Bacia do Canal do Cunha (SBCC) associadas às características demográficas, socioeconômicas e epidemiológicas, com estatística espacial de Moran. A taxa de incidência nos bairros da SBCC foi de 621,5/10.000 habitantes. Complexo do Alemão, Mangueira, e Maré tiveram maiores proporções de casos e mortes. A menor incidência (33,6/10.000 habitantes) e mortalidade (8,3/10.000 habitantes), mas com maior taxa de letalidade (24,7%) foi registrada no Complexo do Alemão. Foi observado correlação negativa entre a taxa de mortalidade e a proporção de habitantes nos bairros com ASN (rho= -0,433; p=0,023). Na estatística espacial, houve correlação inversa para a incidência da Covid-19 (índice Moran, -0,155863; p=0,02). Conclui-se que incidência e mortalidade nas áreas de ASN estão significativamente relacionadas com as estruturas sociodemográficas, demandando o reforço dos sistemas de vigilância e de controle da Covid-19 em territórios de favelas. As recomendações não farmacológicas e a Atenção Primária à Saúde em favelas desempenham relevante papel na redução da transmissão, mortalidade e iniquidades em saúde.

ABSTRACT Along COVID-19 pandemics, Rio de Janeiro (MRJ) has figured among the Brazilian cities with the highest mortality rates. In this study, we explored COVID-19 incidence and mortality in areas with a predominance of subnormal population clusters (SNC) in MRJ. We analyzed 36 neighborhoods of Canal do Cunha Sub-basin (CCSB) and the associations between demographic, socioeconomic, and epidemiological features, and the cumulative incidence, mortality, and lethality rates, and Moran's spatial statistics were performed. The incidence rate in CCSB neighborhoods was 621.5/10,000 inhabitants. Complexo do Alemão, Mangueira, and Maré had the highest proportions of cases and deaths. And the lowest incidence (33.6/10,000 inhabitants), mortality (8.3/10,000 inhabitants), but with the highest lethality rate (24.7%) was recorded in Complexo do Alemão. There was a negative correlation between mortality and the proportion of inhabitants in neighborhoods with ASN (rho= -0.433; p=0.023). In spatial statistics, there was an inverse correlation for the incidence (Moran index, -0.155863; p=0.02). It is concluded that incidence and mortality in SNC areas are significantly related to their sociodemographic structures, highlighting the need to strengthen the surveillance and control systems of COVID-19 in slums territories. Non-pharmacological recommendations and suitable Primary Health Care in slums areas play a relevant role in reducing viral transmission, mortality, and health inequities.

RESUMO

The Internet of Things consists of "things" made up of small sensors and actuators capable of interacting with the environment. The combination of devices with sensor networks and Internet access enables the communication between the physical world and cyberspace, enabling the development of solutions to many real-world problems. However, most existing applications are dedicated to solving a specific problem using only private sensor networks, which limits the actual capacity of the Internet of Things. In addition, these applications are concerned with the quality of service offered by the sensor network or the correct analysis method that can lead to inaccurate or irrelevant conclusions, which can cause significant harm for decision makers. In this context, we propose two systematic methods to analyze spatially distributed data Internet of Things. We show with the results that geostatistics and spatial statistics are more appropriate than classical statistics to do this analysis.

Assuntos

RESUMO

The objective of this study is to provide a view of the geographic distribution of basic sanitation services offered in Parana, Brazil. Temporal distributions, spatial patterns, and clusters were determined using 2000, 2010, and 2016 data. Tabular data of the percentages of households receiving water supply, waste collection, and sanitary sewage treatments were used as the basic inputs of the study. Time series maps were created using geographic information systems (GIS) for the visualization of the temporal changes in basic sanitation rates. The spatial variation in sanitation services was measured using Moran's Global Index (Moran's I), while the Local Indicators of Spatial Association (LISA) and Getis-Ord Gi*(d) were used to identify the presence of possible clusters and hot spots in the percentage of households with sanitation services. The study showed strong evidence that the service rates for sanitary sewage were significantly lower than those for water supply and waste collection. Waste collection proved to have the highest service rate in the study area. Waste collection was also the service that increased the most in the study period, followed by the water supply service. Identification of the most vulnerable municipalities was performed using LISA and the local Getis-Ord Gi*(d) statistic. Most of the low value clusters and cold spots were detected in the southern and west-central regions, while the high value hot spots and clusters were detected in the northern and northeastern regions of the state of Parana.

Assuntos

RESUMO

Vertebrate retina has been shown to be an important target for mercury toxicity and very studies have shown the effect of mercury on the retinal ontogenesis. The nitrergic system plays an important role in the retinal development. The current work studied the effects of methylmercury (MeHg) exposure on the NO-synthase positive neurons (NADPH-diaphorase neurons or NADPH-d+) of the chick retinal ganglion cell layer at embryonic E15 and postnatal P1 days. Retinal flat mounts were stained for NADPH-diaphorase histochemistry and mosaic properties of NADPH-d + were studied by plotting isodensity maps and employing density recovery profile technique. It was also evaluated the protective effect of alpha-tocopherol treatment on retinal tissues exposed to MeHg. MeHg exposure decreased the density of NADPH-d + neurons and altered cell mosaic properties at E15 but had very little or no effect at P1 retinas. Alpha-tocopherol has a protective effect against MeHg exposure at E15. MeHg alterations and alpha-tocopherol protective effect in embryonic retinas were demonstrated to be at work in experimental conditions. MeHg effect in the early phases of visual system development in natural conditions might use the nitrergic pathway and supplementary diet could have a protective effect. At later stages, this mechanism seems to be naturally protected.

Assuntos

RESUMO

This paper proposes alternative models for the analysis of count data featuring a given spatial structure, which corresponds to geographical areas. We assume that the overdispersion data structure partially results from the existing and well justified spatial correlation between geographical adjacent regions, so an extension of existing overdispersion models that include spatial neighborhood structures within a Bayesian framework is proposed. These models allow practitioners to quantify the association explained by the considered neighborhood structures and the one modelled by additional factors. Finally, using the information provided by the Colombian National Demographic and Health Survey, the usefulness of the proposed models is illustrated by fitting them to infant mortality rates and to data including the proportion of mothers who, after giving birth to their last child, underwent a postnatal screening period in Colombia.

Assuntos

RESUMO

Introducción: los defectos del tubo neural se asocian a valores séricos elevados de alfafetoproteína.Objetivo: determinar la prevalencia ajustada de los defectos del tubo neural en la provincia de Villa Clara.Métodos: se realizó un estudio descriptivo retrospectivo donde se incluyeron 43 de los casos nacidos vivos o por interrupción electiva de la gestación por esta causa. Los datos sobre el tipo específico de defecto del tubo neural y los valores séricos de alfafetoproteína materna se obtuvieron del Registro Cubano de Malformaciones Congénitas y del Registro Cubano Prenatal de Malformaciones Congénitas del Centro Provincial de Genética Médica de Villa Clara.Resultados: mediante técnicas de estadística espacial se buscaron conglomerados temporales, espaciales o ambos. Se concluyó que la tasa de prevalencia ajustada fue de 5,47 por cada 1000 recién nacidos. Los niveles séricos de alfafetoproteína resultaron de utilidad para el diagnóstico de los defectos del tubo neural abiertos como la anencefalia.Conclusiones: los hallazgos de conglomerados espaciales y temporales, permitieron identificar los municipios que deben ser objeto de intervención, a través de programas destinados a la identificación y control de posibles factores de riesgo ambientales relacionados con estos defectos congénitos(AU)

Introduction: Neural tube defects are associated to high serum alpha fetoprotein values.Objective: To determine the adjusted prevalence rate of the neural tube defects in Villa Clara province.Methods: A retrospective and descriptive study was conducted in 43 of the infants born alive or from elective cessation of pregnancy because of this problem. Data on specific type of the neural tube defect and the maternal serum alpha fetoprotein values were taken from the Cuban Register of Congenital Malformations and from the Cuban Prenatal Congenital Malformations of the provincial center of medical genetics in Villa Clara province.Results: The spatial statistical techniques allowed finding time, spatial or spatial-time clusters. The adjusted prevalence rate was 5.47 per 1000 newborns. The serum alpha fetoprotein levels observed in the study were useful for the diagnosis of the open neural tube defects such as anencephaly.Conclusions: The spatial and time cluster findings allowed determining those municipalities where intervention is necessary through programs for the detection and control of possible environmental factors related to these congenital defects(AU)

Assuntos

RESUMO

Introducción: los defectos del tubo neural se asocian a valores séricos elevados de alfafetoproteína. Objetivo: determinar la prevalencia ajustada de los defectos del tubo neural en la provincia de Villa Clara. Métodos: se realizó un estudio descriptivo retrospectivo donde se incluyeron 43 de los casos nacidos vivos o por interrupción electiva de la gestación por esta causa. Los datos sobre el tipo específico de defecto del tubo neural y los valores séricos de alfafetoproteína materna se obtuvieron del Registro Cubano de Malformaciones Congénitas y del Registro Cubano Prenatal de Malformaciones Congénitas del Centro Provincial de Genética Médica de Villa Clara. Resultados: mediante técnicas de estadística espacial se buscaron conglomerados temporales, espaciales o ambos. Se concluyó que la tasa de prevalencia ajustada fue de 5,47 por cada 1000 recién nacidos. Los niveles séricos de alfafetoproteína resultaron de utilidad para el diagnóstico de los defectos del tubo neural abiertos como la anencefalia. Conclusiones: los hallazgos de conglomerados espaciales y temporales, permitieron identificar los municipios que deben ser objeto de intervención, a través de programas destinados a la identificación y control de posibles factores de riesgo ambientales relacionados con estos defectos congénitos(AU)

Introduction: Neural tube defects are associated to high serum alpha fetoprotein values. Objective: To determine the adjusted prevalence rate of the neural tube defects in Villa Clara province. Methods: A retrospective and descriptive study was conducted in 43 of the infants born alive or from elective cessation of pregnancy because of this problem. Data on specific type of the neural tube defect and the maternal serum alpha fetoprotein values were taken from the Cuban Register of Congenital Malformations and from the Cuban Prenatal Congenital Malformations of the provincial center of medical genetics in Villa Clara province. Results: The spatial statistical techniques allowed finding time, spatial or spatial-time clusters. The adjusted prevalence rate was 5.47 per 1000 newborns. The serum alpha fetoprotein levels observed in the study were useful for the diagnosis of the open neural tube defects such as anencephaly. Conclusions: The spatial and time cluster findings allowed determining those municipalities where intervention is necessary through programs for the detection and control of possible environmental factors related to these congenital defects(AU)

Assuntos

RESUMO

OBJETIVOS: analizar los patrones espaciales de la migración peruana en la Ciudad de Córdoba, Argentina y comparar la población nacida en Perú que se encuentra agrupada en clústers con aquella dispersa en la ciudad.MÉTODOS: se utilizaron técnicas de estadística espacial y análisis sociodemográfico. En la primera fase se usaron medidas globales de autocorrelación espacial (índice global de Moran) y medidas locales de agrupación espacial para representar clústers de población (Gi* de Getis Ord). En la segunda fase se realiza un análisis sociodemográfico de los clústers de población agrupada y dispersa.RESULTADOS:se sugiere la interacción de dos procesos. En primer lugar, la concentración en zonas específicas de la ciudad de migrantes peruanos en patrones que no son aleatorios. Migrantes más antiguos se encuentran principalmente dispersos en la ciudad mientras migrantes más recientes se encuentran concentrados. En segundo lugar, los migrantes peruanos hombres dispersos tienen una mayor diversificación en cuanto a la estructura ocupacional y una mejor posición socioeconómica que los agrupados. Los patrones observados sugieren que existen diferenciales de género en estos procesos. Las mujeres, tanto las que se encuentran dispersas como las agrupadas, presentan una situación socioeconómica más precaria que los hombres. Esa situación es transversal a la dispersión/concentración en el espacio urbano.CONCLUSIONES:se sugiere que las composiciones de clase, género y la temporalidad de los flujos migratorios articulan las modalidades de incorporación a la sociedad de destino.

OBJECTIVES:to analyze the spatial patterns of Peruvian migration in the city of Cordoba, Argentina and to compare the Peruvian migrants in clusters with Peruvian migrants scattered in the city.METHODS:Spatial statistical techniques and socio-demographic analysis are used for this analysis. In the first phase, global measures of spatial autocorrelation (Global Moran Index) and local measures of spatial clustering represent clusters of population (Getis-Ord Gi*). In the second phase, a sociodemographic analysis of population in clusters and population dispersed is carried out.RESULTS:we suggest there are two entangled processes. First, the concentration in specific areas of the city of Peruvian migrants in patterns that are not random. Older migrants are mainly dispersed in the city while more recent migrants are concentrated. Second, dispersed Peruvian men have greater diversification in terms of occupational structure and better socioeconomic status than Peruvian migrants dispersed. Women both dispersed and in clusters have a more precarious economic situation than men. This situation is transversal to the dispersion / concentration in urban space.CONCLUSIONS: it is suggested that the composition of class, gender and temporality of migration flows articulate the modalities of incorporation in the society of destination.

RESUMO

Diffusion tensor imaging (DTI) studies showed that microstructural alterations are correlated to reading skills. In this study, we aim to investigate white matter microstructure of a group of Portuguese speakers with poor reading level, using different parameters of DTI. To perform this analysis, we selected children ranging from 8 to 12 years of age, poor readers (n = 17) and good readers (n = 23), evaluated in the word-level ability based on a Latent Class Analysis (LCA) of Academic Performance Test (TDE). Poor readers exhibited significant fractional anisotropy (FA) reductions in many tracts of both hemispheres, but small and restricted clusters of increased radial diffusivity (RD) in the left hemisphere. Spatial coherence of fibers might be the main source of differences, as changes in FA were not similarly accompanied in terms of extension by changes in RD. Widespread structural alterations in the white matter could prevent good reading ability at word level, which is consistent with recent studies demonstrating the involvement of multiple cortical regions and white matter tracts in reading disabilities.

Assuntos

RESUMO

Dengue fever is among the most important emerging infectious diseases in the world, and in recent years it has been a source of public concern for the public health control systems of many tropical and subtropical countries. Thus, the purpose of this study was to apply spatial and statistical methodologies to analyze the geographic distribution of dengue and to relate its incidence to the Health Vulnerability Index (HVI), an indicator that integrates different socioeconomic variables to estimate the degree of health vulnerability in different Brazilian cities. The cases of dengue, incidence rates and Bayesian incidence rates were determined using census tracts covering a period of 3 years in a city with socioeconomic and administrative characteristics typical of Brazilian municipalities. Distribution plots, descriptive statistics, kernel density maps, test of global and local spatial autocorrelation and Spearman correlation were used. No association was found between the incidence of dengue and the HVI. Conversely, statistically significant high-incidence clusters were found over the 3 years in an area identified as having lower health vulnerability. The finding that HVI was not a good indicator of dengue in the city studied may be explained by the complexity of the disease. Administrative and financial problems in the municipalities, environmental factors, cultural changes and the emergence of new serotypes are other factors that hinder the understanding and control of the disease. However, the spatial and statistical methodologies used here are suitable and useful tools for the accurate understanding of dengue and other infectious epidemiological processes.

Assuntos

RESUMO

The purely spatial and space-time scan statistics have been successfully used by many scientists to detect and evaluate geographical disease clusters. Although the scan statistic has high power in correctly identifying a cluster, no study has considered the estimates of the cluster relative risk in the detected cluster. In this paper, we evaluate whether there is any bias on these estimated relative risks. Intuitively, one may expect that the estimated relative risks has upward bias, because the scan statistic cherry picks high rate areas to include in the cluster. We show that this intuition is correct for clusters with low statistical power, but with medium to high power, the bias becomes negligible. The same behavior is not observed for the prospective space-time scan statistic, where there is an increasing conservative downward bias of the relative risk as the power to detect the cluster increases.

Assuntos

RESUMO

We studied a surveillance system to prospectively monitor the emergence of space-time clusters in point pattern of disease events. Its aim is to detect a cluster as soon as possible after its emergence, and it is also desired to keep the rate of false alarms at a controlled level. The method is a modification from a previous proposal based on a local version of the Knox statistic and which examined a retrospective surveillance scenario, looking for the earliest time in the past that change could have been deemed to occur. We modify this method to take into account the prospective case, being able then to fix the serious difficulties found by other authors. We evaluated the surveillance system in several scenarios, including without and with emerging clusters, checking distributional assumptions, and assessing performance impacts of different emergence times, shapes, extent, and intensity of the emerging clusters. Our conclusion is that the space-time surveillance system based on local Knox statistics is very efficient in its statistical properties, and it is appealing to epidemiologists and public health officials because it is simple to use and easily understandable. This makes it a promising candidate to practical use by public health official agencies.

Assuntos

RESUMO

Humans vary substantially in their ability to learn new motor skills. Here, we examined inter-individual differences in learning to play the piano, with the goal of identifying relations to structural properties of white matter fiber tracts relevant to audio-motor learning. Non-musicians (n = 18) learned to perform three short melodies on a piano keyboard in a pure audio-motor training condition (vision of their own fingers was occluded). Initial learning times ranged from 17 to 120 min (mean ± SD: 62 ± 29 min). Diffusion-weighted magnetic resonance imaging was used to derive the fractional anisotropy (FA), an index of white matter microstructural arrangement. A correlation analysis revealed that higher FA values were associated with faster learning of piano melodies. These effects were observed in the bilateral corticospinal tracts, bundles of axons relevant for the execution of voluntary movements, and the right superior longitudinal fasciculus, a tract important for audio-motor transformations. These results suggest that the speed with which novel complex audio-motor skills can be acquired may be determined by variability in structural properties of white matter fiber tracts connecting brain areas functionally relevant for audio-motor learning.

Assuntos

RESUMO

The objective of this study was to analyze the spatio-temporal patterns of Aedes aegypti immatures based on four entomological surveys that inspected over 6000 households in a large neighborhood of the city of Clorinda between 2007 and 2008. Global and local spatial point pattern analyses of immature presence or absence, habitat quality (estimated using a previously obtained statistical model) and pupal production were performed. Global analyses showed aggregation of both infestation and habitat quality up to 10 times bigger than previously described, ranging from 150 to 400m between surveys. Pupal production was also clustered but at smaller scales than infestation presence/absence. The location of the clusters was temporally unstable between surveys. There was no spatial structure related to the control strategy; lots treated with temephos and lots uninspected (i.e., closed or refusing) were randomly distributed. These results suggest a combination of exogenous (the aggregation of better quality habitats) and endogenous (dispersal) processes explaining the observed patterns of larger-scale infestation. A spatial targeting strategy at the neighborhood scale would not be as cost-effective in Clorinda as in other sites where stable smaller-scale clusters permit the identification of key premises.

Assuntos

RESUMO

Brazilian beekeeping has been developed from the africanization of the honeybees and its high performance launches Brazil as one of the world´s largest honey producer. The Southeastern region has an expressive position in this market (45%), but the state of Rio de Janeiro is the smallest producer, despite presenting large areas of wild vegetation for honey production. In order to analyze the honey productivity in the state of Rio de Janeiro, this research used classic and spatial regression approaches. The data used in this study comprised the responses regarding beekeeping from 1418 beekeepers distributed throughout 72 counties of this state. The best statistical fit was a semiparametric spatial model. The proposed model could be used to estimate the annual honey yield per hive in regions and to detect production factors more related to beekeeping. Honey productivity was associated with the number of hives, wild swarm collection and losses in the apiaries. This paper highlights that the beekeeping sector needs support and help to elucidate the problems plaguing beekeepers, and the inclusion of spatial effects in the regression models is a useful tool in geographical data.

A apicultura brasileira se desenvolveu a partir da africanização das abelhas melíferas, e seu bom desempenho permitiu lançar o Brasil como um dos maiores produtores mundiais de mel. A região Sudeste ocupa uma posição significativa no mercado, mas o estado do Rio de Janeiro é o menor produtor, apesar de apresentar áreas expressivas de vegetação silvestre para a produção de mel. Para analisar a produtividade de mel no estado do Rio de Janeiro, esta pesquisa estudou diversos métodos de regressão clássica e espacial. Os dados analisados compreenderam respostas sobre apicultura de 1418 apicultores distribuídos em 72 municípios do Rio de Janeiro. O melhor ajuste estatístico utilizado foi um modelo semiparamétrico espacial. A utilidade do modelo proposto é estimar a produção anual de mel por colmeia nas diversas regiões e identificar os fatores de produção mais relacionados à apicultura. A produtividade de mel mostrou-se mais associada com o número de colmeias, a coleta de enxame silvestre e as perdas em apiários. Este trabalho destacou que o segmento apícola necessita de apoio para auxiliar na identificação dos problemas que afetam os apicultores. A utilização de efeitos espaciais em modelos de regressão são ferramentas úteis quando são utilizados dados geograficamente referenciados.

Assuntos

RESUMO

Brazilian beekeeping has been developed from the africanization of the honeybees and its high performance launches Brazil as one of the world´s largest honey producer. The Southeastern region has an expressive position in this market (45%), but the state of Rio de Janeiro is the smallest producer, despite presenting large areas of wild vegetation for honey production. In order to analyze the honey productivity in the state of Rio de Janeiro, this research used classic and spatial regression approaches. The data used in this study comprised the responses regarding beekeeping from 1418 beekeepers distributed throughout 72 counties of this state. The best statistical fit was a semiparametric spatial model. The proposed model could be used to estimate the annual honey yield per hive in regions and to detect production factors more related to beekeeping. Honey productivity was associated with the number of hives, wild swarm collection and losses in the apiaries. This paper highlights that the beekeeping sector needs support and help to elucidate the problems plaguing beekeepers, and the inclusion of spatial effects in the regression models is a useful tool in geographical data.(AU)

A apicultura brasileira se desenvolveu a partir da africanização das abelhas melíferas, e seu bom desempenho permitiu lançar o Brasil como um dos maiores produtores mundiais de mel. A região Sudeste ocupa uma posição significativa no mercado, mas o estado do Rio de Janeiro é o menor produtor, apesar de apresentar áreas expressivas de vegetação silvestre para a produção de mel. Para analisar a produtividade de mel no estado do Rio de Janeiro, esta pesquisa estudou diversos métodos de regressão clássica e espacial. Os dados analisados compreenderam respostas sobre apicultura de 1418 apicultores distribuídos em 72 municípios do Rio de Janeiro. O melhor ajuste estatístico utilizado foi um modelo semiparamétrico espacial. A utilidade do modelo proposto é estimar a produção anual de mel por colmeia nas diversas regiões e identificar os fatores de produção mais relacionados à apicultura. A produtividade de mel mostrou-se mais associada com o número de colmeias, a coleta de enxame silvestre e as perdas em apiários. Este trabalho destacou que o segmento apícola necessita de apoio para auxiliar na identificação dos problemas que afetam os apicultores. A utilização de efeitos espaciais em modelos de regressão são ferramentas úteis quando são utilizados dados geograficamente referenciados.(AU)

Assuntos

RESUMO

Spatial patterns of tropical trees and shrubs are important to understanding their interaction and the resultant structure of tropical rainforests. To assess this issue, we took advantage of previously collected data, on Neotropical tree and shrub stem identified to species and mapped for spatial coordinates in a 50ha plot, with a frequency of every five years and over a 20 year period. These stems data were first placed into four groups, regardless of species, depending on their location in the vertical strata of the rainforest (shrubs, understory trees, mid-sized trees, tall trees) and then used to generate aggregation patterns for each sampling year. We found shrubs and understory trees clumped at small spatial scales of a few meters for several of the years sampled. Alternatively, mid-sized trees and tall trees did not clump, nor did they show uniform (regular) patterns, during any sampling period. In general (1) groups found higher in the canopy did not show aggregation on the ground and (2) the spatial patterns of all four groups showed similarity among different sampling years, thereby supporting a “shifting mosaic” view of plant communities over large areas. Spatial analysis, such as this one, are critical to understanding and predicting tree spaces, tree-tree replacements and the Neotropical forest patterns, such as biodiversity and those needed for sustainability efforts, they produce.

Con datos obtenidos previamente, se identificaron especies de árboles y arbustos neotropicales y se ubicaron con coordenadas espaciales en una parcela de 50ha cada cinco años durante un período de 20 años. Estos datos primero se dividieron en cuatro grupos según los estratos verticales del bosque (arbustos, árboles del sotobosque, árboles medios y árboles altos); después se usaron tres para estudiar patrones de agregación en cada año de muestreo. Los arbustos y árboles del sotobosque se agruparon en pequeñas escalas espaciales de pocos metros en varios de los años del estudio, mientras que los árboles de tamaño medio y grande no se agregaron ni mostraron patrones regulares en ningún período de muestreo. En general: (1) Las especies más altas del dosel perdieron la agregación en el terreno y (2) Los patrones espaciales de todos los grupos de especies mostraron similitud entre los años de muestreo, lo que apoya la idea de un “mosaico cambiante” de las comunidades vegetales en grandes áreas. El análisis espacial, como este, es fundamental para comprender y predecir los espacios arbóreos, el reemplazo de árbol por árbol y los patrones de los bosques neotropicales, tal como la diversidad y aquellos esfuerzos necesarios para garantizar la sostenibilidad, que producen.

Assuntos