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PubMed1990

Modern European cranial variables and blood polymorphisms show comparable spatial patterns.

Spatial patterns in cranial traits for modern European populations are compared with patterns described by Sokal et al. (1989) for blood polymorphisms. Spatial patterns in these variables are described from both one-dimensional and directional autocorrelation correlograms. Manhattan distances computed among one-dimensional correlograms are used (1) to cluster variables with similar patterns and (2) to test the hypothesis that these clusters are to some extent accounted for by the type of variable. The one-dimensional correlograms for cranial traits do not show a significant contrast with either red cell antigens or the set of blood polymorphisms that excludes HLA. The only contrast that accounts for any of the cluster structure among one-dimensional correlograms is that between HLA and non-HLA variables. A cluster analysis of the directional correlograms demonstrates that cranial traits reflect patterns comparable to those for blood polymorphisms. This finding implies that patterns in cranial variables can be accounted for by the same, or similar, population processes as those inferred from patterns in blood polymorphisms. The implications of this finding for the likely origin of the northwest-southeast cline seen in some modern blood polymorphisms and modern cranial variables, but not in Neolithic cranial variables, are discussed.

Antigens↗

PubMed1997

Surveillance systems for monitoring the development of spatial patterns.

Statistical methods concerned with the identification of temporal patterns may be classified into those that examine retrospectively a set of observations, and those that constitute surveillance systems that monitor changes as new observations become available. A similar distinction applies to the identification of geographical patterns in spatial data. There has been a notable lack of attention given to the surveillance of spatial pattern. This paper concerns development of a cumulative sum statistic and procedure for the monitoring of spatial pattern, and its application to both simulated data and to data on Burkitt's lymphoma in Uganda.

Adolescent↗

PubMed2002

Negative information: both presence and absence of spatial pattern elements guide rats' spatial choices.

Rats learn the spatial pattern in which hidden caches of food are located. Once the pattern is learned, finding one or more baited locations provides (positive) information about the remaining baited locations. In the present experiment, we examined whether negative information (the absence of food in a location) would also be used in locating the remaining baited locations. Rats were tested in an apparatus containing a matrix of vertical poles, on top of which food could be hidden. At the beginning of the trial, the location of the baited poles was unpredictable, but the poles were always arranged in a linear pattern. The rats learned the pattern and used both positive and negative information in locating baited poles.

Animals↗

PubMed2003

Spatial patterns of mitochondrial and nuclear gene pools in chamois (Rupicapra r. rupicapra) from the Eastern Alps.

We have assessed the variability of maternally (mtDNA) and biparentally (allozymes) inherited genes of 443 chamois (Rupicapra r. rupicapra) from 19 regional samples in the Eastern Alps, to estimate the degree and patterns of spatial gene pool differentiation, and their possible causes. Based on a total mtDNA-RFLP approach with 16 hexanucleotide-recognizing restriction endonucleases, we found marked substructuring of the maternal gene pool into four phylogeographic groups. A hierarchical AMOVA revealed that 67.09% of the variance was partitioned among these four mtDNA-phylogroups, whereas only 8.04% were because of partitioning among regional samples within the populations, and 24.86% due to partitioning among individuals within regional samples. We interpreted this spatial pattern of mtDNA variability as a result of immigration of chamois from different Pleistocene refugia surrounding the Alps after the withdrawal of glaciers, rather than from topographic barriers to gene flow, such as Alpine valleys, extended glaciers or woodlands. However, this striking geographical structuring of the maternal genome was not paralleled by allelic variation at 33 allozyme loci, which were used as nuclear DNA markers. Wright's hierarchical F-statistics revealed that only < or =0.45% of the explained allozymic diversity was because of partitioning among the four mtDNA-phylogroups. We conclude that this discordance of spatial patterns of nuclear and mtDNA gene pools results from a phylogeographic background and sex-specific dispersal, with higher levels of philopatry in females.

Animals↗

PubMed2006

Statistical inference using the g or K point pattern spatial statistics.

Spatial point pattern analysis provides a statistical method to compare an observed spatial pattern against a hypothesized spatial process model. The G statistic, which considers the distribution of nearest neighbor distances, and the K statistic, which evaluates the distribution of all neighbor distances, are commonly used in such analyses. One method of employing these statistics involves building a simulation envelope from the result of many simulated patterns of the hypothesized model. Specifically, a simulation envelope is created by calculating, at every distance, the minimum and maximum results computed across the simulated patterns. A statistical test is performed by evaluating where the results from an observed pattern fall with respect to the simulation envelope. However, this method, which differs from P. Diggle's suggested approach, is invalid for inference because it violates the assumptions of Monte Carlo methods and results in incorrect type I error rate performance. Similarly, using the simulation envelope to estimate the range of distances over which an observed pattern deviates from the hypothesized model is also suspect. The technical details of why the simulation envelope provides incorrect type I error rate performance are described. A valid test is then proposed, and details about how the number of simulated patterns impacts the statistical significance are explained. Finally, an example of using the proposed test within an exploratory data analysis framework is provided.

Data Interpretation, Statistical↗

PubMed2006

A continuum mechanical model of mechanoreceptive afferent responses to indented spatial patterns.

Information about the spatial structure of tactile stimuli is conveyed by slowly adapting type 1 (SA1) and rapidly adapting (RA) afferents innervating the skin. Here, we investigate how the spatial properties of the stimulus shape the afferent response. To that end, we present an analytical framework to characterize SA1 and RA responses to a wide variety of spatial patterns indented into the skin. This framework comprises a model of the tissue deformation produced by any three-dimensional indented spatial pattern, along with an expression that converts the deformation at the receptor site into a neural response. We evaluated 15 candidate variables for the relevant receptor deformation and found that physical quantities closely related to local membrane stretch were most predictive of the observed afferent responses. The main outcome of this study is an accurate working model of SA1 and RA afferent responses to indented spatial patterns.

Action Potentials↗

PubMed1995

Spatial analysis of Honolulu motor vehicle crashes: I. Spatial patterns.

This study describes spatial patterns in Honolulu motor vehicle accidents for 1990. A method for geo-coding accident locations is utilized with approximately 98% of the crash locations being identified. Spatial software tools are developed for describing the degree of spatial concentration. The spatial patterns of different types of accidents and accidents for every hour of the day, weekdays and weekends separately, are analyzed. Accidents spatially fluctuate dynamically, as a response to changing traffic patterns and volume. Generally, most accidents are closer to employment centers than to residential areas. In the suburban and rural areas, however, accidents are more likely to involve fatalities or serious injuries and be related to night-time driving and alcohol. It is shown that these conditions spatially correlate with single-vehicle crashes and crashes with opposite direction vehicles. The spatial patterns point to the limits of "blackspot" analysis.

Accidents, Traffic↗

PubMed2026

Dissecting spatial patterning and signaling with directional diffusion in spatial multi-omics.

Spatial multi-omics sequencing enables the simultaneous profiling of transcriptomics, proteomics, and epigenomics at a spatial resolution, offering insights into complex tissue organization and molecular regulation. However, the effective integration of multiple omics modalities in a spatial context remains a major challenge. Here, we present SpaDDM, a spatial multi-omics integration framework based on directional diffusion models (DDMs), which supports spatial pattern identification, cross-omics alignment, and inter-and intracellular signaling flow analysis. SpaDDM employs DDM-based graph networks to learn omics-specific representations by jointly incorporating spatial coordinates and molecular measurements within each modality, followed by an attention mechanism to align features across modalities. We benchmarked SpaDDM on diverse spatial multi-omics datasets, including transcriptomics-epigenomics and transcriptomics-proteomics combinations across multiple tissues and species. SpaDDM consistently outperformed existing methods by more accurately deciphering spatial tissue patterns and effectively reducing the boundary noise between spatial regions. Moreover, the learned low-dimensional coembedded representations of individual cells serve as integral mediators for inferring the signaling flows that underlie spatial patterning. Finally, we demonstrated that SpaDDM alignment of complementary information across multi-omics layers facilitates cross-omics translation and significantly improves the prediction of cell state alignments.

Multiomics↗

PubMed1997

Using Moment Equations to Understand Stochastically Driven Spatial Pattern Formation in Ecological Systems

Spatial patterns in biological populations and the effect of spatial patterns on ecological interactions are central topics in mathematical ecology. Various approaches to modeling have been developed to enable us to understand spatial patterns ranging from plant distributions to plankton aggregation. We present a new approach to modeling spatial interactions by deriving approximations for the time evolution of the moments (mean and spatial covariance) of ensembles of distributions of organisms; the analysis is made possible by "moment closure," neglecting higher-order spatial structure in the population. We use the growth and competition of plants in an explicitly spatial environment as a starting point for exploring the properties of second-order moment equations and comparing them to realizations of spatial stochastic models. We find that for a wide range of effective neighborhood sizes (each plant interacting with several to dozens of neighbors), the mean-covariance model provides a useful and analytically tractable approximation to the stochastic spatial model, and combines useful features of stochastic models and traditional reaction-diffusion-like models. Copyright 1997 Academic Press. Copyright 1997 Academic Press

Journal Article↗

PubMed2006

Spatial pattern learning in the radial arm maze.

Rats experienced a spatial pattern of baited and unbaited arms in an eight-arm radial maze. The spatial pattern remained constant over trials, but the spatial locations that were baited varied unpredictably. Although there was no evidence of control by the spatial pattern during free choice training trials, the rats' ability to locate baited arms in forced choice test trials was superior to that of animals in a control condition for which maze arms were not baited in a consistent spatial pattern. This is consistent with the results of experiments showing that spatial choices by rats in a pole box maze are controlled by abstract spatial patterns.

Animals↗

PubMed2003

[Quantification comparison of spatial pattern of soil seed bank of Fraxinus mandshurica in two stands].

The spatial pattern of soil seed bank of Fraxinus mandshurica were examined by geostatistics in two stands with different densities, tree species composition and ground plants, in the Northeast of China. A sampling grid of 559 points, at each point a sample was located, was established according to regular grid design at three spatial scales (cell size were 0.5 m x 0.5 m, 1 m x 1 m, and 2 m x 2 m) in each plot. Spatial pattern were quantified by using semivariance analysis, fractal dimension and Kriging maps. The object of this paper is to quantify the spatial pattern of seed bank, to compare its variations between two stands, and to explore what sort of mechanism would control its variations. The results indicated seed distribution showed appreciable heterogeneity within stand and clearly difference between the two stands. In plot 1 (mixed stand), seed bank, with a mean of 158.1 +/- 96.7 seeds.m-2, higher sill (C0 + C = 0.549) and 4.25 m scales, has a stronger spatial pattern. There were a high autocorrelated variation (89.4%) and lowly random variation (10.6%) at this scale. However, at scale from 5 m to 31.3 m, its autocorrelated variation ranged 51.4%-69.8% and random variation ranged 30.2%-47.6%, also has distinctly mosaic patterns. Fractal dimension (D) analysis showed that the D values was relatively lower(1.728-1.865), their coefficient of variation only about 26.7%-68.35%, indicated that there was a high self-similarity of patch shapes of seed bank. In plot 2 (pure stand), with a mean of 57.4 +/- 44.7 seed.m-2, and lower sill (C0 + C = 0.125), spatial patterns were not so strong as plot 1, which has a smaller scale (2.59 m). Its spatially autocorrelated variation was 56.8% and randomly variation was 43.2%. Over the scale there were no clearly autocorrelated spatial patterns. Fractal dimension analysis showed higher D value (1.906-1.960), and their coefficient of variation varying wildly (69.51%-134.14%), implying highly random variation and more complex patch shapes. The differences of spatial pattern of seed bank between the two stands were likely to be due to spatial heterogeneity at the level of stands.

Seeds↗

PubMed1994

The spatial patterns of beta/A4 deposit subtypes in Down's syndrome.

The spatial patterns of diffuse, primitive and classic beta/A4 deposits were studied in coronal sections of the hippocampus and adjacent gyri in 11 cases of Down's syndrome (DS) varying in age from 38 to 67 years. The objectives of the study were first, to compare the spatial patterns of beta/A4 deposits revealed in DS with those reported in cases of Alzheimer's disease (AD) and second, to study how the spatial patterns of beta/A4 deposits may develop in the tissue. The spatial patterns revealed in DS exhibited a number of similarities with those reported in AD: (1) the range and frequency of the different types of spatial pattern revealed were similar, (2) beta/A4 deposits occurred in clusters and in many cortical tissues, the clusters were distributed in a regular pattern parallel to the pia, (3) the clusters of diffuse and primitive beta/A4 deposits occurred in an alternating pattern along the cortex, and (4) the clusters of classic beta/A4 deposits were not correlated with the clusters of the diffuse and primitive deposits. Primitive deposits may develop from the diffuse deposits in regions of the cortex where extracellular paired helical filaments were formed. However, clusters of the classic beta/A4 deposits, which are formed in older cases, appear to develop independently of the diffuse and primitive deposits.

Adult↗

PubMed2003

Spatial pattern of ecosystem function and ecosystem conservation.

The spatial pattern of ecosystem function can affect ecosystem conservation. Ecosystem functions are often heterogeneous spatially due to physical and biological factors. We can influence ecosystem functions by changing the spatial patterns of the physical and biological elements of an ecosystem and regulating their combinations. The variation-position effect highlights a phenomenon resulting from the spatial pattern of ecosystem function. The effect shows that the identical variation of a factor may produce different effects on the over-all situation when this variation occurs in a different spatial position. In a watershed of the Yangtze River, water retention is a primary ecosystem function. The variation-position effect for water retention capacity occurs in the watershed because of the spatial heterogeneity in vegetation, soil, and slope. The change of vegetation that occurs in a complex can affect the overall situation of water retention, and the effect can be different due to the change occurring in the position holding different vegetation-soil-slope complex. To improve the ecosystem in the watershed and to meet the social needs for the ecosystem function of water retention, a strategy called "ecosystem function and spatial pattern-based forest extension" was proposed to conserve forests. The implementation of the strategy enables the watershed to attain the maximum effective increase in water retention capacity.

Conservation of Natural Resources↗

PubMed2003

Variation in spatial pattern of criteria air pollutants before and during initial rain of monsoon.

Spatial patterns of various criteria air pollutants, like SO2, NO2, O3, and TSP were studied at Shahdara National Ambient Air Quality Monitoring station in Delhi (India) in July 1999. The minimum pollutant concentrations were observed during morning hours, whereas the highest concentrations were found during the late night hours, which seem to be related with the vehicular emission. Pre-monsoon daily ambient air quality spatial pattern was compared with the spatial pattern during initial and subsequent rain shower of monsoon. These spatial patterns were found to be essentially the same before and during rain, however a significant decrease in SO2, NO2 and TSP concentrations (40-45%) was observed after initial and subsequent rains of the monsoon, demonstrating the importance of rainfall in the scavenging of these criteria air pollutants.

Air Pollutants↗

PubMed2003

[Analysis on instantaneous spatial pattern of thermal force field in Harbin].

The spatial pattern of urban thermal force field is not only the dominant content in assessing city ecological environment, but also an important base for city green system planning. The status of spatial pattern of thermal force field in Harbin was analyzed with RS and GIS techniques. Based on the instantaneous radiation temperature of the land surfaces in the city when the TM image was sensed remotely, all the patches were divided into 3 levels, i.e., low radiation temperature (< 10 degrees C), middle radiation temperature (10-22 degrees C), and high radiation temperature of the land surfaces (22-31 degrees C). The patches with high radiation temperature accounted for 61%, those with low radiation temperature accounted for 17%, and those with middle radiation temperature accounted for 22%. 7018 patches (12,252 hm2 in total) with super-thermal radiation (> 28 degrees C) were uneven in their areas. The biggest area in these patches was 1489 hm2, and the smallest one was 0.72 hm2. The proportion of the patches with an area less than 1 hm2, between 1-5 hm2, and more than 5 hm2 was 95.02%, 3.46%, and 1.58%, respectively. There were 3 types of spatial patterns of the super-thermal radiation patches, i.e., round form (the average radiation temperature was 30.8 degrees C), ring form (the average radiation temperature was 27 degrees C), and pieces form (the average radiation temperature was 24.7 degrees C). Daowai District and Daoli District were round form, districts along the ring routes of railway in the city were ring form, and Nangang District and Dongli District were pieces form. Some advices to resolve the problem of 'heat island effect' influenced by the factors including greenland covering rate, greenland area and building dimension were discussed.

City Planning↗

PubMed2002

[Spatial pattern of Tetranychus urticae population in apple tree garden].

Spatial pattern of insect population is an important aspect of insect ecology. It reveals the spatial structure characteristics of populations, and provides a basis for relevant sampling techniques and data transformation. Tetranychus urticae Koch is a serious pest of apple tree. Its spatial pattern and time-series dynamics were analyzed by calculating four indices of aggregation, and parameters of Iwao model. The results showed that the spatial pattern of T. urticae in apple tree garden belonged to an aggregated distribution pattern. The aggregation intensity was the highest in upper and southern part of crown, and the lowest in its lower and inner part. The aggregation was due to the biological habits of T. urticae and environmental heterogeneity. No matter T. urticae was in the upper, middle, or lower crown of apple tree, its aggregation intensity was higher before first ten days of June, and then gradually decreased after the middle ten days of June.

Acari↗

PubMed1994

Spatial patterns in the background EEG underlying mental disease in man.

The spatial patterns underlying differences in the background EEGs of schizophrenic, manic and depressed patients and a group of normal controls has been examined during the eyes open and eyes closed resting conditions and during 3 cognitive tasks. The method of principal-component analysis was used to extract spatial patterns which are common to the EEGs of 2 groups but which account for maximally different proportions of the combined variances. The common spatial patterns in all possible pairings of the groups were used to extract variance-related feature vectors from the individual EEG epochs in the 2 groups and the means of these vectors were subjected to statistical analyses. The results of these analyses indicate that there are significant differences in the EEGs from all 4 of the groups. The spatial patterns underlying the features which are significantly different in each comparison are shown graphically and used to suggest which brain regions might be implicated in each of the psychiatric conditions and how these are affected by the cognitive condition. The main results are that the EEGs in the schizophrenic group can be characterized by left-sided hyperactivity, in the depressed group by right-sided hyperactivity and in the manic group by bilateral hyperactivity and that these characteristics are best elicited by different cognitive states.

Adult↗

PubMed2002

The spatial patterns of prion protein deposits in cases of variant Creutzfeldt-Jakob disease.

The spatial patterns of the prion protein (PrP) deposits were studied in immunostained sections of areas of the cerebral cortex, hippocampus, dentate gyrus, and the molecular layer of the cerebellum in 11 cases of variant Creutzfeldt-Jakob disease (vCJD). Clustering of PrP deposits, with a regular distribution of the clusters parallel to the tissue boundary, was the most common spatial pattern observed. Two morphological types of PrP deposit were recognised, those consisting of a condensed core (florid deposits) and those deposits lacking a condensed core (non-florid deposits). The florid and non-florid PrP deposits exhibited a different profile of spatial patterns. First, the florid deposits exhibited a regularly distributed pattern of clusters more frequently than the non-florid deposits. Second, the florid deposits formed larger clusters (greater than 1,600 micro m in diameter) less frequently than the non-florid deposits. In the areas of the cerebral cortex that exhibited a regular distribution of PrP deposit clusters, the cluster size of the deposits approximated that of the groups of cells of the cortico-cortical pathway origin in only 12% of analyses. No significant differences in the frequency of the different types of spatial pattern were observed in different brain regions, or in the cerebral cortex between the upper and lower laminae. It was concluded that the spatial patterns of the PrP deposits in the cerebral cortex in vCJD are unlikely to reflect the degeneration of the cortico-cortical pathways as has been reported in sporadic CJD (sCJD). In addition, different factors could be involved in the development of the deposits with and without a condensed core.

Adolescent↗