Spatial Association Patterns Research Articles

Estrutura espacial e mobilidade urbana: estudo sistêmico aplicado à Região Metropolitana de Goiânia

A dificuldade de se compreender a organização das cidades instiga a busca por descobrir uma lógica na dinâmica urbana de maneira mais abrangente e não fragmentada. Trazer o pensamento sistêmico para o urbanismo, ou seja, assumir as cidades enquanto sistemas complexos, oferece uma possibilidade de abordagem integral do espaço urbano. Neste trabalho, considera-se que a estrutura espacial da cidade é um macrossistema repleto de campos a serem investigados, buscando a compreensão das relações entre esses campos e suas interações com a cidade. A mobilidade urbana, enquanto uma das áreas de análise, é considerada um campo essencial para o entendimento da estrutura socioeconômica e espacial intraurbana, conectando pessoas ao território urbano. Esse estudo adota como base a análise sistêmica aplicada à mobilidade dentro do contexto da estrutura espacial urbana. Objetiva-se, para tal, identificar e analisar as relações entre a estrutura espacial e a mobilidade urbana na Região Metropolitana de Goiânia (RMG). A pesquisa é de natureza básica, exploratória, descritiva e baseada principalmente em análises quali-quantitativas. Adota-se o uso da análise espacial georreferenciada a partir de um modelo inferencial que busca expor a relação entre eixos escolhidos. O modelo adotado é o de autocorrelação espacial, construído a partir de uma análise exploratória para identificação de localizações atípicas (outliers) e padrões de associação espacial (clusters) por meio de mapas das variáveis em estudo. Como resultado da pesquisa, explora-se as relações existentes entre a estrutura espacial e a mobilidade urbana na RMG testando a hipótese de a teoria sistêmica ser uma ferramenta capaz de auxiliar na compreensão de relações urbanas.

Spatial Association Pattern of Air Pollution and Influencing Factors in the Beijing–Tianjin–Hebei Air Pollution Transmission Channel: A Case Study in Henan Province

The Beijing–Tianjin–Hebei (BTH) air pollution transmission channel and its surrounding areas are of importance to air pollution control in China. Based on daily data of air quality index (AQI) and air pollutants (PM2.5, PM10, SO2, NO2, CO, and O3) from 2015 to 2016, this study analyzed the spatial and temporal characteristics of air pollution and influencing factors in Henan Province, a key region of the BTH air pollution transmission channel. The result showed that non-attainment days and NAQI were slightly improved at the provincial scale during the study period, whereas that in Hebi, Puyang, and Anyang became worse. PM2.5 was the largest contributor to the air pollution in all cities based on the number of non-attainment days, but its mean frequency decreased by 21.62%, with the mean occurrence of O3 doubled. The spatial distribution of NAQI presented a spatial agglomeration pattern, with high-high agglomeration area varying from Jiaozuo, Xinxiang, and Zhengzhou to Anyang and Hebi. In addition, the NAQI was negatively correlated with sunshine duration, temperature, relative humidity, wind speed, and positively to atmospheric pressure and relative humidity in all four clusters, whereas relationships between socioeconomic factors and NAQI differed among them. These findings highlight the need to establish and adjust regional joint prevention and control of air pollution as well as suggest that it is crucially important for implementing effective strategies for O3 pollution control.

Microstructural and biochemical diversity of forest soil organic surface layers revealed by density fractionation

Particularly on sites with shallow, nutrient-poor soils, forest soil organic surface layers (O layers) are important for the storage of plant-available nutrients and water, and thus for forest vitality and productivity. O layers can contain up to 70 mass percent of inorganic compounds (minerals) which may be spatially separated from or closely associated with soil organic matter (SOM). O layer SOM may differ in biochemical properties and resistance against mineralization, depending on the extent of organo-mineral association. Moreover, type and intensity of SOM-mineral mixing in O layers conveys information about biological activity. Here, for the first time we present detailed density fractionation results to distinguish SOM constituents in O layers with different chemical properties and likely also different degrees of organo-mineral association. Additionally, we characterized spatial association patterns of the SOM fractions. We investigated samples of Of (Oe) and Oh (Oa) horizons of temperate forest soils with different parent materials (basalt, gneiss, andesite, Pleistocene gravel, dolomite). The samples were distinguished into six density fractions (ρ < 0.8 g cm−3; 0.8–1.0 g cm−3; 1.0–1.2 g cm−3; 1.2–1.4 g cm−3; 1.4–1.6 g cm−3; >1.6 g cm−3) by sequential treatment with deionized H2O (ρ = 1.0 g cm−3), 1-propanol (ρ = 0.8 g cm−3), and sodium polytungstate (SPT) solution of increasing density (ρ = 1.2, 1.4, 1.6 g cm−3). The procedure is characterized by a mass recovery of 93 ± 5% and an organic carbon (OC) recovery of 90 ± 9%. In each fraction, we analyzed the concentrations of C, N, metal cations (Fe, Al, Ca, Mg), C speciation (13C NMR spectroscopy), as well as abundances of 13C and 15N. For selected fractions, we additionally determined the radiocarbon age and acquired microscopic images. From the Of to the Oh horizons, the contribution of heavy fractions (>1.4 g cm−3) to total soil mass and total SOC increased, indicating augmented organo–mineral association with progressive SOM decomposition state. Compared to bulk soil, heavier fractions >1.4 g cm−3 were characterized by smaller SOC concentrations, whereas concentrations of Al and Fe were increased for fractions >1.4 g cm−3 in the of and >1.6 g cm−3 in the Oh horizon. The SOM in the heavy fractions was enriched in N, carboxyl C, and alkyl C, but depleted in O/N-alkyl C and aryl C. Smaller mean particle sizes and C/N ratios as well as increased alkyl C / O/N-alkyl C ratios and 13C and 15N abundances indicate an advanced SOM decomposition state and enrichment of microbial-derived SOM in heavier fractions. However, according to its 14C signature, in contrast to high-density (ρ > 1.6 g cm−3) SOM in the mineral soil, forest floor SOM with high density is a rapidly cycling SOM pool with a turnover time <50 years.

Testing the link between species interactions and species co‐occurrence in a trophic network

Species interactions are dynamic processes that vary across environmental and ecological contexts, and operate across scale boundaries, making them difficult to quantify. Nevertheless, ecologists are increasingly interested in inferring species interactions from observational data using statistical analyses of their spatial co‐occurrence patterns. Trophic interactions present a particular challenge, as predators and prey may frequently or rarely co‐occur, depending on the spatial or temporal scale of observation. In this study, we investigate the accuracy of inferred interactions among species that both compete and trophically interact. We utilized a long‐term dataset of pond‐breeding amphibian co‐occurrences from Mt Rainier National Park (Washington, USA) and compiled a new dataset of their empirical interactions from the literature. We compared the accuracy of four statistical methods in inferring these known species interactions from spatial associations. We then used the best performing statistical method, the Markov network, to further investigate the sensitivity of interaction inference to spatial scale‐dependence and the presence of predators. We show that co‐occurrence methods are generally inaccurate when estimating trophic interactions. Further the strength and sign of inferred interactions were dependent upon the spatial scale of observation and predator presence influenced the detectability of competitive interactions among prey species. However, co‐occurrence analysis revealed new patterns of spatial association among pairs of species with known interactions. Overall, our study highlights a limiting frontier in co‐occurrence theory and the disconnect between widely implemented methodologies and their ability to accurately infer interactions in trophically‐structured communities.

Examining the Relationship Between Spatial Configurations of Urban Impervious Surfaces and Land Surface Temperature

The urban heat island (UHI) effect has significant effects on the quality of life and public health. Numerous studies have addressed the relationship between UHI and the increase in urban impervious surface area (ISA), but few of them have considered the impact of the spatial configuration of ISA on UHI. Land surface temperature (LST) may be affected not only by urban land cover, but also by neighboring land cover. The aim of this research was to investigate the effects of the abundance and spatial association of ISAs on LST. Taking Harbin City, China as an example, the impact of ISA spatial association on LST measurements was examined. The abundance of ISAs and the LST measurements were derived from Landsat Thematic Mapper (TM) imagery of 2000 and 2010, and the spatial association patterns of ISAs were calculated using the local Moran’s I index. The impacts of ISA abundance and spatial association on LST were examined using correlation analysis. The results suggested that LST has significant positive associations with both ISA abundance and the Moran’s I index of ISAs, indicating that both the abundance and spatial clustering of ISAs contribute to elevated values of LST. It was also found that LST is positively associated with clustering of high-ISA-percentage areas (i.e.,>50%) and negatively associated with clustering of low-ISA-percentage areas (i.e.,<25%). The results suggest that, in addition to the abundance of ISAs, their spatial association has a significant effect on UHIs.

The impact of food provisioning on parasite infection in wild black capuchin monkeys: a network approach

Nonhuman primates host a variety of gastrointestinal parasites that infect individuals through different transmission routes. Social contact among group members (e.g., body contact, grooming) brings the risk of parasite infection, especially when the pathogen infection is directly transmitted. Along with this, accidental provisioning (i.e., food provisioning occurring during close tourist-wildlife interactions) is also considered to increase the risk of infection, as aggregation during feeding can cause higher exposure to parasite infective stages. However, while some attention has been paid to the relationship between social behavior and parasites, the link between accidental food provisioning and characteristics of parasite infection in primates has thus far received less attention. This study examines the potential effect of accidental provisioning on patterns of inter-individual spatial association, and in turn on parasite infection risk in a wild group of black capuchin monkeys (Sapajus nigritus) in Iguazú National Park, Argentina. To do so, we simulated events of accidental provisioning via researcher-managed provisioning experiments and tested whether experimental provisioning affects the inter-individual spatial distribution within groups. In addition, we determined whether patterns of parasite infection were better predicted by naturally occurring spatial networks (i.e., spatial association during natural observations) or by provisioning spatial networks (i.e., spatial interactions during experimental provisioning). We found a significant increase in network centrality that was potentially associated with an overall increase in individual connections with other group members during experimental trials. However, when assessing the effects of natural and provisioning network metrics on parasite characteristics, we did not observe a significant effect of centrality measures (i.e., closeness and betweenness) on parasite richness and single infection by Filariopsis sp. Taken together, our findings suggest that alterations of within-group spatial networks due to accidental provisioning may have a limited influence in determining the characteristics of parasite infections in black capuchin monkeys.

Spatial Association Patterns of Geographic Factors and Opisthorchis Viverrini Infection in the Northeast of Thailand

Spatial Association Patterns of Geographic Factors and Opisthorchis Viverrini Infection in the Northeast of Thailand

Influence of microhabitat on functional attributes of two columnar cacti with different distribution ranges

Microhabitat variations condition the ability of plant populations to colonize and recruit. Normally cacti species need nurse conditions for establishment of seedlings, resulting in patches under forest cover and increasing the contrasting conditions between slopes with different solar exposure and humidity percentage. We hypothesize that Cephalocereus senilis, a species with restricted range, will have constant functional attributes at each slope and therefore greater sensitivity to environmental variation than Stenocereus dumortieri, a species of wide distribution. This study contrasts microhabitat response of two cacti with different distribution ranges using several functional traits: spatial association pattern, variation in morphological attributes, habitat disturbance conditions and community association. The main contributions of this work are: i) use of a multivariate approach that allows observation of variation patterns between different conditions of exposure and ii) contrast of wide and restricted distribution species in response to dry environmental requirements. The functional attributes of C. senilis are constant (density, morphology, disturbance conditions and associated vegetation), with the exception of the spatial arrangement of individuals, clumped towards an eastern orientation and regularly spaced on the western orientation. In contrast, S. dumortieri has different functional attributes, performing better on unexposed hillsides (aggregation radii smaller, highest density, larger plants, more preserved environment and greater diversity of associated vegetation). Our results are an example of the general response to micro-environmental variation of wide (tolerance) and restricted (avoidance) species in dry environments at both the population and community levels, representing an evolutionary evidence of adaption divergence.

Identifying wildfire-prone atmospheric circulation weather types on mainland Spain

In this paper we present a detailed spatial assessment of the association between atmospheric synoptic conditions (the weather types, WT) and fires on the Spanish mainland. The WT approach allows the continuum of atmospheric fields to be compressed into a few comprehensive patterns, providing meaningful information on the movement of air masses, wind direction and, ultimately, wind speed. We analyzed a total of 291,547 individual fires from the official Spanish Fire database (1974–2014) and corresponding daily WT patterns on the Iberian Peninsula from the daily NCEP/NCAR Reanalysis database, 1951–2015. Underlying spatial patterns of association among fire and weather types were explored by means of self-organizing maps (SOM) coupled to hierarchical clustering.Our analyses have detected that fires tend to occur and become largermore likely under certain atmospheric conditions suggesting that specific weather patterns can promote or boost fire events. From a pyrogeographical point of view, the contribution of WTs to wildfires on the Spanish mainland seems to be highly diverse, and displays several temporal and spatial patterns. The northwest region responds mostly to eastern flows during summer and southern during winter. Fires in the northern Mediterranean coast are promoted by northerly flows while in southern regions fires are linked to C or SE extreme heat episodes during summer. Overall, fires activity usually increases in the lee ward of mountain ranges depending on the prevalent flow from WTs, and thus related to adiabatic heating of the air flow.

Spatial Distribution Pattern of the Headquarters of Listed Firms in China

This study chose 4667 listed firms with headquarters in China as the research objects. The spatial aggregations of headquarters in sub-periods and subsectors were investigated based on prefecture-level cities using Global Moran’s I statistic, the Getis-Ord Gi* statistic, and kernel density estimation. The spatial association and frequent patterns of headquarters belonging to different sectors were analyzed using the Apriori algorithm. The results showed the following: (1) Most headquarters of listed firms agglomerate around megacities and concentrate in the coastal regions. (2) Many prefer that headquarters be located in an area within a 5 km radius, forming the pivotal local industry cluster. (3) Industrial, information technology, and consumer discretionary firms show a higher degree of agglomeration than materials and health care firms. Materials and consumer discretionary industries have a stronger spillover effect on surrounding cities compared to industrial, information technology, and health care firms. (4) Service industries show a strong spatial association with other sectors at all distance thresholds and frequent items. These results can provide a reference for future considerations of headquarters locations, industrial development, and the reshaping of urban networks.

An Entrogram‐Based Approach to Describe Spatial Heterogeneity With Applications to Solute Transport in Porous Media

AbstractThe recently introduced geological entropy concept evaluates spatial order/disorder in the structure of the hydraulic conductivity (K) field to explain and predict certain characteristics of transport behavior. This concept is expanded in this work by introducing a novel tool for spatial analysis called entrogram from which a metric called entropic scale (HS) can be calculated to measure the overall persistency of patterns of spatial association in a distributed field and to allow robust comparisons between different spatial structures. The entrogram and the entropic scale concepts are applied here to investigate the link between solute transport behavior and the spatial structure of K fields modeled as the distribution of three hydrofacies in alluvial aquifers. Accurate empirical relationships are found between HS and key transport quantities confirming the clear correlation between transport and the structure of the K field described in terms of its entropic scale. The entrogram analysis is also applied to continuous 2‐D and 3‐D fields having identical lognormal K distributions, but with different connectivity. Comparisons between the entrograms and the calculated HS values for these fields, as well as for their corresponding flow velocity distributions, shed light on the key differences among these structures in 2‐D and in 3‐D, which in turn explain their dissimilar impact on solute transport. The entrogram‐based interpretation of the transport simulations seems to confirm that the geological entropy is a promising approach for predicting solute transport behavior simply from a description of the K field heterogeneity.

Influence of biotic interactions on the distribution of Canada lynx (Lynx canadensis) at the southern edge of their range

The persistence of cold-adapted species along their equatorial range edge (i.e., southern range edge for species in the Northern Hemisphere and northern range edge for species in the Southern Hemisphere) is threatened by climate change. These species will be challenged not just by unfavorable climatic regimes, but also by changing biotic interactions, which may be more intense along equatorial edges. However, we currently have a poor understanding of the nature of biotic interactions at range edges and how climate may mediate those interactions, particularly for cold-adapted mammals. We studied the distribution of threatened Canada lynx (Lynx canadensis) at their southern range edge in northern Washington, United States from 2014 to 2016. Using data collected from 397 camera-trap stations in snow-on and snow-off seasons, and single- and 2-species occupancy models, we investigated seasonal patterns of habitat selection and spatial association of lynx with their primary prey (snowshoe hares, Lepus americanus) and potential competitors (bobcats, Lynx rufus; cougars, Puma concolor). Single-species occupancy models revealed lynx distribution was strongly associated with snowshoe hare abundance and topographic variables related to lower temperatures and increased moisture. In contrast, bobcats and cougars were more generalized in their habitat associations or displayed the reverse response to environmental variables. Spatial overlap of the 3 felid species increased during snow-off seasons. Two-species occupancy models showed a decrease in use of camera sites by lynx when bobcats were present, suggesting lynx were avoiding their warm-adapted competitor. Taken together, these results suggest that biotic interactions are partly shaping large-scale lynx distribution patterns along their southern range edge. Increasing temperatures and loss of snow may result in a combination of habitat isolation and potential for increased competitive interactions for lynx at the margins of their range.

Urban green valuation integrating biophysical and qualitative aspects

ABSTRACTUrban green mapping has become an operational task in city planning, urban land management, and quality of life assessments. As a multi-dimensional, integrative concept, urban green comprising several ecological, socio-economic, and policy-related aspects. In this paper, the author advances the representation of urban green by deriving scale-adapted, policy-relevant units. These so-called geons represent areas of uniform green valuation under certain size and homogeneity constraints in a spatially explicit representation. The study accompanies a regular monitoring scheme carried out by the urban municipality of the city of Salzburg, Austria, using optical satellite data. It was conducted in two stages, namely SBG_QB (10.2 km², QuickBird data from 2005) and SBG_WV (140 km², WorldView-2 data from 2010), within the functional urban area of Salzburg. The geon delineation was validated by several quantitative measures and spatial analysis techniques, as well as ground documentation, including panorama photographs and visual interpretation. The spatial association pattern was assessed by calculating Global Moran’s I with incremental search distances. The final geonscape, consisting of 1083 units with an average size of 13.5 ha, was analyzed by spatial metrics. Finally, categories were derived for different types of functional geons. Future research paths and improvements to the described strategy are outlined.

Synaptic configuration of quadrivalents and their association with the XY bivalent in spermatocytes of Robertsonian heterozygotes of Mus domesticus

BackgroundThe nuclear architecture of meiotic prophase spermatocytes is based on higher-order patterns of spatial associations among chromosomal domains and consequently is prone to modification by chromosomal rearrangements. We have shown that nuclear architecture is modified in spermatocytes of Robertsonian (Rb) homozygotes of Mus domesticus. In this study we analyse the synaptic configuration of the quadrivalents formed in the meiotic prophase of spermatocytes of mice double heterozygotes for the dependent Rb chromosomes: Rbs 11.16 and 16.17.ResultsElectron microscope spreads of 60 pachytene spermatocytes from four animals of Mus domesticus 2n = 38 were studied and their respective quadrivalents analysed in detail. Normal synaptonemal complex was found between arms 16 of the Rb metacentric chromosomes, telocentrics 11 and 17 and homologous arms of the Rb metacentric chromosomes. About 43% of the quadrivalents formed a synaptonemal complex between the heterologous short arms of chromosomes 11 and 17. This synaptonemal complex is bound to the nuclear envelope through a fourth synapsed telomere, thus dragging the entire quadrivalent to the nuclear envelope. About 57% of quadrivalents showed unsynapsed single axes in the short arms of the telocentric chromosomes. About 90% of these unsynapsed quadrivalents also showed a telomere-to-telomere association between one of the single axes of the telocentric chromosome 11 or 17 and the X chromosome single axis, which was otherwise normally paired with the Y chromosome. Nucleolar material was associated with two bivalents and with the quadrivalent.ConclusionsThe spermatocytes of heterozygotes for dependent Rb chromosomes formed a quadrivalent where four chromosomes are synapsed together and bound to the nuclear envelope through four telomeres. The nuclear configuration is determined by the fourth shortest telomere, which drags the centromere regions and heterochromatin of all the chromosomes towards the nuclear envelope, favouring the reiterated encounter and eventual rearrangement between the heterologous chromosomes. The unsynapsed regions of quadrivalents are frequently bound to the single axis of the X chromosome, possibly perturbing chromatin condensation and gene expression.

The roles of stochasticity and biotic interactions in the spatial patterning of plant species in alpine communities

AbstractQuestionsPlant community composition can be influenced by multiple biotic, abiotic, and stochastic factors acting on the local species pool to determine their establishment success and abundance and subsequently the diversity of the community. We asked if the influences of biotic interactions on the composition of plant species in communities, as indicated by patterns of plant species spatial associations (independent, positive or negative), vary across a productivity gradient within a single ecosystem type. Do dominant species of communities show spatial patterning suggestive of competitive interactions with interspecific neighbors? Do species that span multiple community types exhibit the same heterospecific interactions with neighbours in each community?LocationThree alpine communities in the southern Rocky Mountains.MethodsWe measured the occurrence of species in a 1‐cm spatial grid within 2 m × 2 m plots to determine the spatial patterns of species pairs in the three communities. A null model of independent species spatial arrangements was used to determine whether species pairs were positively, negatively or independently associated, and how these patterns differed among the communities across the gradient of resource supply and environmental stress.ResultsPositive associations, indicative of facilitation between species, were most common in the most resource‐poor and least productive community. However negative associations, suggestive of competitive interactions among species, were not more common in the two more resource‐rich, productive communities. The dominant species of these communities did exhibit higher negative than positive associations with neighbours relative to positive patterning. Independent interspecific patterning was equally common relative to positive and negative patterns in all communities. Species that previously were shown to either facilitate other species or compete with neighbours exhibited spatial patterning consistent with the earlier experimental work.ConclusionsA large number of species exhibit a lack of net biotic interactions, and stochastic factors appear to be as important as competition and facilitation in shaping the structure of the three alpine plant communities we studied.

A new method based on association rules mining and geo-filter for mining spatial association knowledge

Association rule mining methods, as a set of important data mining tools, could be used for mining spatial association rules of spatial data. However, applications of these methods are limited for mining results containing large number of redundant rules. In this paper, a new method named Geo-Filtered Association Rules Mining (GFARM) is proposed to effectively eliminate the redundant rules. An application of GFARM is performed as a case study in which association rules are discovered between building land distribution and potential driving factors in Wuhan, China from 1995 to 2015. Ten sets of regular sampling grids with different sizes are used for detecting the influence of multi-scales on GFARM. Results show that the proposed method can filter 50%–70% of redundant rules. GFARM is also successful in discovering spatial association pattern between building land distribution and driving factors.

Tree-based approach for exploring marine spatial patterns with raster datasets.

From multiple raster datasets to spatial association patterns, the data-mining technique is divided into three subtasks, i.e., raster dataset pretreatment, mining algorithm design, and spatial pattern exploration from the mining results. Comparison with the former two subtasks reveals that the latter remains unresolved. Confronted with the interrelated marine environmental parameters, we propose a Tree-based Approach for eXploring Marine Spatial Patterns with multiple raster datasets called TAXMarSP, which includes two models. One is the Tree-based Cascading Organization Model (TCOM), and the other is the Spatial Neighborhood-based CAlculation Model (SNCAM). TCOM designs the “Spatial node→Pattern node” from top to bottom layers to store the table-formatted frequent patterns. Together with TCOM, SNCAM considers the spatial neighborhood contributions to calculate the pattern-matching degree between the specified marine parameters and the table-formatted frequent patterns and then explores the marine spatial patterns. Using the prevalent quantification Apriori algorithm and a real remote sensing dataset from January 1998 to December 2014, a successful application of TAXMarSP to marine spatial patterns in the Pacific Ocean is described, and the obtained marine spatial patterns present not only the well-known but also new patterns to Earth scientists.

Nuclear Architecture of Mouse Spermatocytes: Chromosome Topology, Heterochromatin, and Nucleolus

The nuclear organization of spermatocytes in meiotic prophase I is primarily determined by the synaptic organization of the bivalents that are bound by their telomeres to the nuclear envelope and described as arc-shaped trajectories through the 3D nuclear space. However, over this basic meiotic organization, a spermatocyte nuclear architecture arises that is based on higher-ordered patterns of spatial associations among chromosomal domains from different bivalents that are conditioned by the individual characteristics of chromosomes and the opportunity for interactions between their domains. Consequently, the nuclear architecture is species-specific and prone to modification by chromosomal rearrangements. This model is valid for the localization of any chromosomal domain in the meiotic prophase nucleus. However, constitutive heterochromatin plays a leading role in shaping nuclear territories. Thus, the nuclear localization of nucleoli depends on the position of NORs in nucleolar bivalents, but the association among nucleolar chromosomes mainly depends on the presence of constitutive heterochromatin that does not affect the expression of the ribosomal genes. Constitutive heterochromatin and nucleoli form complex nuclear territories whose distribution in the nuclear space is nonrandom, supporting the hypothesis regarding the existence of a species-specific nuclear architecture in first meiotic prophase spermatocytes.

Novel Algorithm for Mining ENSO-Oriented Marine Spatial Association Patterns from Raster-Formatted Datasets

The ENSO (El Nino Southern Oscillation) is the dominant inter-annual climate signal on Earth, and its relationships with marine environments constitute a complex interrelated system. As traditional methods face great challenges in analyzing which, how and where marine parameters change when ENSO events occur, we propose an ENSO-oriented marine spatial association pattern (EOMSAP) mining algorithm for dealing with multiple long-term raster-formatted datasets. EOMSAP consists of four key steps. The first quantifies the abnormal variations of marine parameters into three levels using the mean-standard deviation criteria of time series; the second categorizes La Nina events, neutral conditions, or El Nino events using an ENSO index; then, the EOMSAP designs a linking–pruning–generating recursive loop to generate (m + 1)-candidate association patterns from an m-dimensional one by combining a user-specified support with a conditional support; and the fourth generates strong association patterns according to the user-specified evaluation indicators. To demonstrate the feasibility and efficiency of EOMSAP, we present two case studies with real remote sensing datasets from January 1998 to December 2012: one considers performance analysis relative to the ENSO-Apriori and Apriori methods; and the other identifies marine spatial association patterns within the Pacific Ocean.

Mule deer spatial association patterns and potential implications for transmission of an epizootic disease.

Animal social behaviour can have important effects on the long-term dynamics of diseases. In particular, preferential spatial relationships between individuals can lead to differences in the rates of disease spread within a population. We examined the concurrent influence of genetic relatedness, sex, age, home range overlap, time of year, and prion disease status on proximal associations of adult Rocky Mountain mule deer (Odocoileus hemionus hemionus) in a chronic wasting disease endemic area. We also quantified the temporal stability of these associations across different sex, age, and disease status classes. We used three years of high frequency telemetry data from 74 individuals to record encounters within 25 m of each other, and to calculate seasonal home range overlap measured by volume of intersection (VI). The strength of pairwise spatial association between adult mule deer was independent of genetic relatedness, age and disease status. Seasonal variation in association strength was not consistent across years, perhaps due to annual changes in weather conditions. The influence of home range overlap on association strength varied seasonally, whereby associations were stronger in pre-rut and fawning than in the rest of the seasons. The sexes of individuals also interacted with both VI and season. At increasing levels of VI, associations were stronger between females than between males and between females and males. The strongest associations in pre-rut were between males, while the strongest in rut were between females and males. The temporal stability of associations was markedly dependant on the sex and the diagnosis of the associating pair. Our findings highlight the importance of considering concurrent effects of biological and environmental factors when seeking to understand the role of social preference in behavioural ecology and disease spread. Applying this knowledge in epidemiological modelling will shed light on the dynamics of disease transmission among mule deer.