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PubMed2004

Zone design for environment and health studies using pre-aggregated data.

Many environment and health studies employ geographical areas as the units of analysis, either through choice or necessity. The design of these areas can greatly influence any observed spatial relationships or patterns-an effect known as the modifiable areal unit problem. In this paper we identify the phenomena and processes which are typically measured in environment and health studies and present a conceptualisation for their representation as data objects in spatial analysis. We discuss the circumstances under which we find ourselves using areas for representation and outline the application of zone design techniques for the creation of such areas in environment and health studies. An empirical study of the relationship between deprivation and limiting long-term illness in the former county of Avon, UK, is employed to demonstrate the potential usefulness of zone design techniques for creating zones with stable estimates and for exploring the sensitivity of relationships to changes in the zoning system. In particular, we illustrate the inappropriateness of the 1991 Census enumeration district and ward zoning systems for such an analysis and conclude that automatically designed aggregations may be a more appropriate basis for analysis than any pre-existing zoning system.

Adolescent↗
PubMed2003

The spatial pattern of risk from arsenic poisoning: a Bangladesh case study.

Arsenic poisoning in Bangladesh has been one of the biggest environmental health and social disasters of recent times. About seventy million people in Bangladesh are exposed to toxic levels of arsenic (0.05 mg/L) in drinking water. It is ironic that so many tubewells have been installed in recent times to provide drinking water that is safe from water-borne diseases but that the water pumped is contaminated with toxic levels of arsenic. Along with the clinical manifestations, some social problems have also emerged due to arsenic toxicity. Analysing the spatial risk pattern of arsenic in groundwater is the main objective of this paper. Establishing the extent of arsenic exposure to the people will facilitate an understanding of the health effects and estimating the population risk over the area. This paper seeks to explore the spatial pattern of arsenic concentrations in groundwater for analyzing and mapping 'problem regions' or 'risk zones' for composite arsenic hazard information by using GIS-based data processing and spatial analysis along with state-of-the-art decision-making techniques. Quantitative data along with spatial information were employed and analyzed for this paper.

Arsenic Poisoning↗
PubMed2004

Anatomical mapping of white matter hyperintensities (WMH): exploring the relationships between periventricular WMH, deep WMH, and total WMH burden.

BACKGROUND AND PURPOSE: MRI segmentation and mapping techniques were used to assess evidence in support of categorical distinctions between periventricular white matter hyperintensities (PVWMH) and deep WMH (DWMH). Qualitative MRI studies generally identify 2 categories of WMH on the basis of anatomical localization. Separate pathophysiologies and behavioral consequences are often attributed to these 2 classes of WMH. However, evidence to support these empirical distinctions has not been rigorously sought. METHODS: MRI analysis of 55 subjects included quantification of WMH volume, mapping onto a common anatomical image, and spatial localization of each WMH voxel. WMH locations were then divided into PVWMH and DWMH on the basis of distance from the lateral ventricles and correlations, with total WMH volume determined. Periventricular distance histograms of WMH voxels were also calculated. RESULTS: PVWMH and DWMH were highly correlated with total WMH (R2>0.95) and with each other (R2>0.87). Mapping of all WMH revealed smooth expansion from around central cerebrospinal fluid spaces into more distal cerebral white matter with increasing WMH volume. CONCLUSIONS: PVWMH, DWMH, and total WMH are highly correlated with each other. Moreover, spatial analysis failed to identify distinct subpopulations for PVWMH and DWMH. These results suggest that categorical distinctions between PVWMH and DWMH may be arbitrary, and conclusions regarding individual relationships between causal factors or behavior for PVWMH and DWMH may more accurately reflect total WMH volume relationships.

Aged↗
PubMedDate not supplied

[Spatial clusters detection of violent deaths in Porto Alegre, Rio Grande do Sul, Brazil, 1996].

Violence is of major importance in the health profile of Brazilian metropolitan areas and should be treated as a public health problem. Spatial analysis methods can be highly useful for the surveillance and prevention of violence. This paper analyzes the spatial distribution of victims' place of residence in relation to the main causes of violent death in Porto Alegre (1996) in order to identify vulnerable areas. For motor vehicle accidents, homicides, and suicide, the victim's place of residence was pinpointed using the municipal Geographic Information System. The point patterns of health events and population density were analyzed using a Kernel smoother, visually compared. Some areas with higher concentration of events are similar to population distribution but differ from each other in the remaining high concentration areas, thus indicating specific micro-areas at risk. Areas of higher homicide risk are mainly located on the periphery of the more urbanized area, with worse socioeconomic conditions. Motor vehicle accidents are concentrated in areas that are simultaneously commercial and residential and are traversed by streets with heavy traffic. Suicide deaths are more evenly distributed over the territory. Identification of risk areas provides meaningful information for developing preventive and health promotion measures focusing on the events for which health policies may play a central role.

Adult↗
PubMedDate not supplied

The distribution and geographical origin of some French surnames.

The geographical distribution of the principal form of a French surname and its close variants (in spelling or pronunciation) has been analysed based on the French births registers, respectively from 1891 to 1915 and from 1916 to 1940, and on telephone directories for 1975. The spatial analysis of the individuals with the principal form of the surname suggests the existence of a positive spatial autocorrelation and three major areas of concentration in central France, the Loire country and Northern France. Within these three main areas of concentration, in 1975 most of the telephone subscribers with the principal surname are listed in rural communes with fewer than 3000 inhabitants, suggesting that the geographical pattern is not recent. Moreover, between the end of the 19th century and 1975 this pattern remains fairly constant. The geographical distribution of the holders of a 'variant' form of the surname shows the existence of a positive correlation between the absolute frequency of the principal surname and that of the variants, but only one area of concentration appears in Loire country. By analogy with the theory of centres of origin in genetics and linguistics, it is suggested that this unique area of concentration could be the region in which the surname originated. If that hypothesis proves to be correct, two main consequences follow: large migration movements occurred before the general rural exodus of the last century, and there has been no major, recent admixture of populations.

Directories as Topic↗
PubMed2003

Remotely sensed data for ecosystem analyses: combining hierarchy theory and scene models.

Remotely sensed data have been used extensively for environmental monitoring and modeling at a number of spatial scales; however, a limited range of satellite imaging systems often constrained the scales of these analyses. A wider variety of data sets is now available, allowing image data to be selected to match the scale of environmental structure(s) or process(es) being examined. A framework is presented for use by environmental scientists and managers, enabling their spatial data collection needs to be linked to a suitable form of remotely sensed data. A six-step approach is used, combining image spatial analysis and scaling tools, within the context of hierarchy theory. The main steps involved are: (1) identification of information requirements for the monitoring or management problem; (2) development of ideal image dimensions (scene model), (3) exploratory analysis of existing remotely sensed data using scaling techniques, (4) selection and evaluation of suitable remotely sensed data based on the scene model, (5) selection of suitable spatial analytic techniques to meet information requirements, and (6) cost-benefit analysis. Results from a case study show that the framework provided an objective mechanism to identify relevant aspects of the monitoring problem and environmental characteristics for selecting remotely sensed data and analysis techniques.

Conservation of Natural Resources↗
PubMed2003

Pedestrian injuries in Mexico: a multi-method approach.

UNLABELLED: Studies of road traffic injuries should identify social determinants amenable to intervention, and should attend to the problems of individual drivers and pedestrians. This is especially true in developing nations like Mexico, where traffic fatality rates are high and interventions ineffective. OBJECTIVE: Combine qualitative and quantitative methods to analyze pedestrian injuries from motor vehicles in Mexico City, and identify their social, contextual and environmental determinants. Methods included (1). a cross-sectional analysis of mortality, producing crude and specific mortality rates and standardized mortality ratios (95% CI) by region; (2). Spatial analysis using a geographic information system to generate maps at different aggregation levels; (3). Observation with cameras to identify traffic patterns, spaces, behaviors, and patterned violations of regulations; and 4). Semi-structured in-depth interviews of pedestrians and drivers involved in an accident. RESULTS: The overall crude mortality rate was 7.14/100000, (CI 6.85-7.42), with differences by sex and region. The highest concentration of deaths was observed in 10 neighborhoods, at specific types of street environments. The high-risk environments have wide avenues with abundant vehicular traffic, where spaces supposedly reserved for pedestrians are invaded by cars and vendors. Many pedestrians have never driven a motor vehicle, few know the traffic signs, and almost all events were "hit and run" cases. CONCLUSIONS: The combination of quantitative and qualitative methods allows us to see the specific importance of some determinants of pedestrian injuries. Spatial, epidemiological, and social perspectives help point out the local accident characteristics which must be considered before defining preventive interventions.

Accidents, Traffic↗
PubMed2026

Mycosis Fungoides-Like Atopic Dermatitis Represents a Th22-Dominant Inflammatory Endotype.

BACKGROUND: Early-stage mycosis fungoides (MF) often presents diagnostic challenges because of its clinical overlap with atopic dermatitis (AD). In clinical practice, we encountered a subset of patients with severe AD who fulfilled the MF diagnostic criteria yet remained clinically indistinguishable from AD and presented refractoriness to advanced therapies. We termed this ambiguous entity "mycosis fungoides-like AD" (mfAD) and sought to determine whether it represents malignant transformation or a distinct inflammatory endotype of AD. METHODS: Skin biopsies were obtained from 7 patients with AD and 11 patients with mfAD. We performed paired single-cell RNA sequencing and single-cell T-cell receptor sequencing analyses. Publicly available MF and AD datasets were integrated for comparative analysis. Spatial transcriptomic profiling was used to contextualize single-cell findings within the tissue architecture. RESULTS: Comparative transcriptomic analysis revealed that T cells in mfAD were aligned with those in AD and lacked genomic instability. High-resolution profiling showed that mfAD was characterized by oligoclonal Th22 expansion rather than a single dominant malignant clone. Notably, all patients with mfAD achieved rapid clinical remission with selective JAK1 inhibition, indicating the therapeutic response characteristics of inflammatory dermatoses. CONCLUSION: Our findings demonstrate that mfAD is not a true malignancy, but rather a Th22-driven inflammatory endotype of AD. These results redefine mfAD as an inflammatory subtype within the AD spectrum, providing a mechanistic explanation for both the "pseudo-monoclonality" that leads to MF misdiagnosis and the failure of dupilumab. This study establishes a rationale for the use of JAK inhibitors in precision medicine for this patient population.

JAK inhibitor↗
PubMed2006

Tick-borne encephalitis in the Baltic States: identifying risk factors in space and time.

This paper presents preliminary results in our investigations of the biological (abiotic and biotic) and non-biological causes of the spatial heterogeneity and temporal change of tick-borne encephalitis (TBE), both within and between Estonia, Latvia, and Lithuania. Spatial analysis revealed that the land cover and precise seasonal patterns of climatic indices (temperature and normalized difference vegetation index) can explain 55% of the observed spatial variation in TBE incidence over the period 1993-98 across all the Baltic States. Temporal analysis of climatic variables indicates a very specific change in spring temperature conditions from 1993 onwards that could enhance the transmission of TBE virus. Further time series analysis of climate, together with analysis of biotic factors, socio-economic conditions, and human behaviour is being undertaken to explain the epidemiological patterns more fully.

Animals↗
PubMed2003

The spatial tuning of chromatic adaptation.

A key question in colour research is how the colour and spatial analysis of an image interact. Traditionally, colour and form analysis have been regarded as parallel and separate processes, and documented effects of image complexity on chromatic adaptation have been attributed to a temporal integration process during eye movements. Evidence is presented here for a spatial mechanism, which tunes chromatic adaptation to the luminance structure (spatial frequency and orientation) of an image. This in turn suggests a close cooperation between colour and form analysis during chromatic adaptation. The results are discussed in relation to the "segregated pathway hypothesis" and the role of spatial aspects for the computation of colour constancy and adaptation to natural scenes.

Adaptation, Ocular↗
PubMed2002

Respiration-induced B0 fluctuations and their spatial distribution in the human brain at 7 Tesla.

In functional magnetic resonance imaging (fMRI), it is known that physiological influences such as cardiac pulsation, respiration, and brain motion can induce fluctuations in signal intensity and phase. Some of the mechanisms potentially involved in those phenomena are expected to be amplified at higher magnetic fields. This study addresses the issue of B(0) fluctuations induced by susceptibility changes during respiration attributed to movements of chest and diaphragm, and variations in the oxygen concentration. It is demonstrated that respiration-induced resonance offsets (RIROs) are significant at 7T. Data were acquired with an RF pulse (no gradients), multislice echo-planar imaging (EPI), and dynamic 3D fast low-angle shot (3D- FLASH) imaging. Three main observations summarize the experimental findings. First, in FIDs measured after a single RF pulse, a RIRO with a large amplitude was consistently detected, although the average amplitude varied between subjects from 1.45 Hz to 4 Hz. Second, in transverse EPI images obtained in the occipital lobe, the RIRO amplitude showed a monotonic increase along the z axis toward the lungs. Third, a more detailed spatial analysis with 3D-FLASH phase maps revealed that a previously published analytical model can accurately describe the spatial distribution of RIRO. Consequential apparent motions in the EPI series, as well as the implications of slice orientation for correction strategies are discussed.

Brain↗
PubMed1999

Measuring facial expressions by computer image analysis.

Facial expressions provide an important behavioral measure for the study of emotion, cognitive processes, and social interaction. The Facial Action Coding System (Ekman & Friesen, 1978) is an objective method for quantifying facial movement in terms of component actions. We applied computer image analysis to the problem of automatically detecting facial actions in sequences of images. Three approaches were compared: holistic spatial analysis, explicit measurement of features such as wrinkles, and estimation of motion flow fields. The three methods were combined in a hybrid system that classified six upper facial actions with 91% accuracy. The hybrid system outperformed human nonexperts on this task and performed as well as highly trained experts. An automated system would make facial expression measurement more widely accessible as a research tool in behavioral science and investigations of the neural substrates of emotion.

Adult↗
PubMed1985

Cross correlation studies in primate motor cortex: synaptic interaction and shared input.

Awake, unrestrained monkeys were trained to reach out with the forelimb and touch a button. Extracellular spike trains were recorded from pairs of neurons in contralateral precentral cortex with the same or separate microelectrodes. The neurons were located in the same or different functional columns as defined by intracortical microstimulation and passive sensory stimulation. Cross correlation analysis showed patterns consistent with synaptic excitation and/or inhibition between members of the cell pairs during the voluntary movement. The strength of correlation was inversely related to distance between columns, with the strongest correlations found between cells within the same column. Inhibitory correlations were virtually restricted to cell pairs within a single column. Temporal analysis showed that direct synaptic interaction and shared input patterns could be clearly distinguished in this physiologic setting. Spatial analysis indicated that shared input was concentrated among columns in the same and adjacent joint controlling zones as well as within a single column. No directional preference of shared input was present, a finding which was consistent with the observed nested organization of the forelimb area.

Action Potentials↗
PubMed2006

A GIS tool to estimate West Nile virus risk based on a degree-day model.

West Nile virus (Flaviviridae: Flavivirus) is a serious infectious disease that recently spread across the North America continent. A spatial analysis tool was developed on the ArcMap 9.x platform to estimate potential West Nile virus activity using a spatially explicit degree-day model. The model identifies when the virus Extrinsic Incubation Period (EIP) is completed within the vector longevity during mid-summer months. The EIP is treated as a threshold indicator of the potential for virus emergence and activity. Comparing the number of West Nile virus cases in Wyoming reported from 2003 to 2005 with model results, actual cases and predicted events of West Nile virus activity match relatively well. The model represents a useful method for estimating potential West Nile virus activity in a large spatial scale.

Disease Outbreaks↗
PubMed1997

Multifactorial comparative study of spatial point pattern analysis methods.

A way of studying cooperative behaviour of biological entities (proteins, cells, etc.) is by using topographical analysis: the quantification of the spatial patterns formed by the entities considered as points. Five methods of topographical analysis were compared in terms of discriminant power, stability of parameters, methodological bias and algorithms. We tested five methods (nearest neighbour distribution, radial distribution, Voronoï paving, quadrat count, minimal spanning tree graph) which generated nine parameters on four simulated models (random point process, hardcore model and two cluster models) and on experimental cellular models. The method which offers the best discrimination power and stability seems to be the minimal spanning tree graph edge length distribution.

Animals↗
PubMed2005

Geospatial analysis of hepatitis C in Connecticut: a novel application of a public health tool.

OBJECTIVES: This study aimed to use geographic information systems (GIS) that facilitate analysis of associations between location, environment and disease to document the non-random distribution of hepatitis C, identify infection cluster areas, and describe the demographic characteristics of those areas. METHODS: Spatial analysis was conducted of newly reported positive hepatitis C test results using the Connecticut Hepatitis C Reporting Database. A complete database of unduplicated hepatitis C laboratory reports that were sent to the Connecticut Department of Public Health during 1999 was created. Spatial filtering was used to eliminate random noise generated by sparsely populated towns or small number of cases per town. Cluster analysis was used to determine whether cases of hepatitis C virus (HCV) infection tend to occur closer in space to other cases than would be expected by chance alone. The demographic attributes of identified clusters of HCV-positive reports were examined. RESULTS: Areas with the highest concentration of HCV reports roughly correspond to the major metropolitan areas of Connecticut. Six significant clusters of HCV reports were identified in Connecticut. Four of the six clusters identified were located in the most densely populated and most urban areas of the state. All but one identified cluster had been described previously as areas of substantial injection drug use, as indicated by their designation as five of the sites of syringe exchange programmes in Connecticut. This finding suggests that geospatial analysis may assist in the identification of clusters that would not otherwise be suspected based on local demographics or other characteristics. CONCLUSIONS: These findings contribute significantly to the understanding of the state-specific epidemiology of HCV infection. This methodology can be applied wherever a similar database exists to enable the implementation of targeted prevention and educational campaigns to raise awareness of HCV risk factors, the importance of being tested, and treatment options.

Cluster Analysis↗
PubMedDate not supplied

Spatial partitioning using multivariate cluster analysis and a contiguity algorithm.

Spatial analysis of epidemiological data can be a useful tool for identifying patterns of disease occurrence and can provide substantial support for prevention and control strategies. To obtain the greatest spatial resolution, it is important to use the smallest available areal units with homogeneous population. However, small areas usually have a small population, introducing spurious variability in the chosen indicators of disease occurrence. This paper describes an approach for combining small geographical units to stabilize mortality rates by pooling information across areas according to specified risk profiles. The procedure is based on a principal component analysis, followed by a cluster analysis of social-economic indicators to classify the risk profile of each small area. The classification is used in an algorithm to join neighbouring areas with similar profiles until an estimated population size is achieved. We applied this method to two Administrative Regions of the city of Rio de Janeiro, Brazil, using the census tracts as the basic areal unit. Census tracts were classified according to four socioeconomic categories distributed spatially as a mosaic, where tracts of differing categories neighbour each other. The aggregation algorithm produced a new partition of the region studied, with the created areal units preserving the internal socioeconomic homogeneity.

Adult↗
PubMed2006

A spatially explicit resource-based approach for managing stream fishes in riverscapes.

The article describes a riverscape approach based on landscape ecology concepts, which aims at studying the multiscale relationships between the spatial pattern of stream fish habitat patches and processes depending on fish movements. A review of the literature shows that few operational methods are available to study this relationship due to multiple methodological and practical challenges inherent to underwater environments. We illustrated the approach with literature data on a cyprinid species (Barbus barbus) and an actual riverscape of the Seine River, France. We represented the underwater environment of fishes for different discharges using two-dimensional geographic information system-based maps of the resource habitat patches, defined according to activities (feeding, resting, and spawning). To quantify spatial patterns at nested levels (resource habitat patch, daily activities area, subpopulation area), we calculated their composition, configuration, complementation, and connectivity with multiple spatial analysis methods: patch metrics, moving-window analysis, and least cost modeling. The proximity index allowed us to evaluate habitat patches of relatively great value, depending on their spatial context, which contributes to the setting of preservation policies. The methods presented to delimit potential daily activities areas and subpopulation areas showed the potential gaps in the biological connectivity of the reach. These methods provided some space for action in restoration schemes.

Animals↗