Identification of Plane and Spatial Clustered Distributions of Particulate Inclusions

2004 ◽  
Author(s):  
Ryszard Pyrz
Keyword(s):  
Clustered Distributions

scholarly journals A Novel Approach to Bridging Physical, Cultural, and Socioeconomic Indicators with Spatial Distributions of Agricultural Heritage Systems (AHS) in China

2020 ◽  
Vol 12 (17) ◽  
pp. 6921
Author(s):  
Guilin Liu ◽  
Domenico M. Doronzo
Keyword(s):  
Spatial Distribution ◽  
Rural Areas ◽  
Land Surface ◽  
Local Governments ◽  
Eastern China ◽  
Agricultural Products ◽  
Western China ◽  
Socioeconomic Indicators ◽  
High Quality ◽  
Clustered Distributions

This paper aimed at analyzing the spatial distribution and variation of agricultural heritage systems (AHSs) in China. In particular, the spatial relationships between AHS sites and influencing factors were analyzed by employing a spatial analysis approach, i.e., solving for cause–effect relations. Then, two reasonable pathways for protecting AHSs were proposed following this methodology. The results showed that the number of AHS sites in eastern China was larger than in western China. This peculiar distribution is thought to be affected by distinctive natural resource endowments and sociocultural traits of local agricultural systems. Indeed, a series of natural, sociocultural, and economic factors were analyzed to reveal their relationships with AHSs. In China, AHS sites have excellent and unique natural conditions, and their clustered distributions positively correlate with the spatial distribution of high-quality agricultural products and the biological abundance index; on the other hand, they negatively correlate with the relief degree of the land surface and GDP. Further results showed that regions with AHSs were mainly located in rural areas of major Chinese cultural zones. In conclusion, two pathways of implementation of high-quality agricultural products and agro-tourism were proposed in order to play an integrated economic, social, and ecological function for protecting AHSs in China. These scientific findings may encourage local governments to protect AHSs and the transition of rural communities.

scholarly journals Clustered Breeding Sites: Shelters for Vector-Borne Diseases

2018 ◽  
Vol 2018 ◽  
pp. 1-5 ◽  
Author(s):  
J. C. A. Dias ◽  
L. H. A. Monteiro
Keyword(s):  
Host Population ◽  
Spatial Distributions ◽  
Breeding Sites ◽  
Vector Borne Diseases ◽  
Vector Abundance ◽  
Probabilistic Cellular Automaton ◽  
Time Variations ◽  
Vector Borne ◽  
Clustered Distributions ◽  
Homogeneous Distributions

Here, the propagation of vector-borne diseases is modeled by using a probabilistic cellular automaton. Numerical simulations considering distinct spatial distributions and time variations of the vector abundance are performed, in order to investigate their impacts on the number of infected individuals of the host population. The main conclusion is as follows: in the clustered distributions, the prevalence is lower, but the eradication is more difficult to be achieved, as compared to homogeneous distributions. This result can be relevant in the implementation of preventive surveillance measures.

Freeze-fractured cardiac gap junctions: structural analysis by three methods

1983 ◽  
Vol 244 (4) ◽  
pp. H525-H539
Author(s):  
E. Page ◽  
T. Karrison ◽  
J. Upshaw-Earley
Keyword(s):  
Gap Junctions ◽  
Nearest Neighbor ◽  
Particle Density ◽  
Particle Diameter ◽  
Optical Diffraction ◽  
Published Data ◽  
Quick Freezing ◽  
Junctional Permeability ◽  
Membrane Ultrastructure ◽  
Clustered Distributions

In isolated rat left ventricles perfused at 37 degrees C with control, Ca2+-loading, and Ca2+-depleting solutions (pH 7.3-7.4), we have investigated freeze-fractured gap junctional membrane by three quantitative techniques designed to correlate changes in junctional permeability with changes in membrane ultrastructure, i.e., 1) optical diffraction, 2) direct measurement of center-to-center spacings and particle diameters, and 3) statistical analysis of the spatial distribution of P-face particles based on analysis of nearest neighbor center-to-center distances. Junctions fixed either with glutaraldehyde or by quick freezing were compact, with closely packed rather than dispersed membrane particles even in the permeable state. Analysis of variance for all three methods indicated that replication was a major variability source limiting structural discrimination. Discrimination between random, regular, and clustered distributions depended critically on particle diameter and particle density. The results differ from published data of others on mammalian ventricular gap junctions and from measurements by our laboratory on sheep cardiac Purkinje fibers (J. Ultrastruct. Res. 75: 195-204, 1981).

scholarly journals “Gap hunting” to characterize clustered probe signals in Illumina methylation array data

2016 ◽  
Author(s):  
Shan V. Andrews ◽  
Christine Ladd-Acosta ◽  
Andrew P. Feinberg ◽  
Kasper D. Hansen ◽  
M. Daniele Fallin
Keyword(s):  
Association Studies ◽  
Data Driven ◽  
Probe Type ◽  
450K Array ◽  
Methylation Array ◽  
Association Analyses ◽  
Data Driven Approach ◽  
Efficient Data ◽  
Dna Strand ◽  
Clustered Distributions

AbstractBackgroundThe Illumina 450K array has been widely used in epigenetic association studies. Current quality-control (QC) pipelines typically remove certain sets of probes, such as those containing a SNP or with multiple mapping locations. An additional set of potentially problematic probes are those with DNA methylation (DNAm) distributions characterized by two or more distinct clusters separated by gaps. Data-driven identification of such probes may offer additional insights for downstream analyses.ResultsWe developed a procedure, termed “gap hunting”, to identify probes showing clustered distributions. Among 590 peripheral blood samples from the Study to Explore Early Development, we identified 11,007 “gap probes”. The vast majority (9,199) are likely attributed to an underlying SNP(s) or other variant in the probe, although SNP-affected probes exist that do not produce a gap signals. Specific factors predict which SNPs lead to gap signals, including type of nucleotide change, probe type, DNA strand, and overall methylation state. These expected effects are demonstrated in paired genotype and 450k data on the same samples. Gap probes can also serve as a surrogate for the local genetic sequence on a haplotype scale and can be used to adjust for population stratification.ConclusionsThe characteristics of gap probes reflect potentially informative biology. QC pipelines may benefit from an efficient data-driven approach that “flags” gap probes, rather than filtering such probes, followed by careful interpretation of downstream association analyses. Our results should translate directly to the recently released Illumina 850K EPIC array given the similar chemistry and content design.

Clustered or dispersed: testing the effect of sampling strategy to census burrow-nesting petrels with varied distributions at sub-Antarctic Marion Island

2019 ◽  
Vol 31 (05) ◽  
pp. 231-242
Author(s):  
Ben J. Dilley ◽  
David W. Hedding ◽  
Dominic A.W. Henry ◽  
Kalinka Rexer-Huber ◽  
Graham C. Parker ◽  
...  
Keyword(s):  
Information System ◽  
Small Groups ◽  
Sampling Strategy ◽  
Breeding Population ◽  
Marion Island ◽  
Survey Techniques ◽  
Population Sizes ◽  
Procellaria Aequinoctialis ◽  
Clustered Distributions ◽  
Random Survey

AbstractWe compared systematic and random survey techniques to estimate breeding population sizes of burrow-nesting petrel species on Marion Island. White-chinned (Procellaria aequinoctialis) and blue (Halobaena caerulea) petrel population sizes were estimated in systematic surveys (which attempt to count every colony) in 2009 and 2012, respectively. In 2015, we counted burrows of white-chinned, blue and great-winged (Pterodroma macroptera) petrels within 52 randomized strip transects (25 m wide, total 144 km). Burrow densities were extrapolated by Geographic Information System-derived habitat attributes (geology, vegetation, slope, elevation, aspect) to generate island-wide burrow estimates. Great-winged petrel burrows were found singly or in small groups at low densities (2 burrows ha−1); white-chinned petrel burrows were in loose clusters at moderate densities (3 burrows ha−1); and blue petrel burrows were in tight clusters at high densities (13 burrows ha−1). The random survey estimated 58% more white-chinned petrels but 42% fewer blue petrels than the systematic surveys. The results suggest that random transects are best suited for species that are widely distributed at low densities, but become increasingly poor for estimating population sizes of species with clustered distributions. Repeated fixed transects provide a robust way to monitor changes in colony density and area, but might fail to detect the formation/disappearance of new colonies.

The Spatial Pattern of Ski Areas and Its Driving Factors in China: A Strategy for Healthy Development of the Ski Industry

2020 ◽  
Author(s):  
Hongmin An ◽  
Cunde Xiao ◽  
Minghu Ding
Keyword(s):  
Spatial Pattern ◽  
Spatial Autocorrelation ◽  
Economic Benefits ◽  
Driving Factors ◽  
Economic Factors ◽  
Mountain Areas ◽  
Ski Resorts ◽  
Ski Industry ◽  
Ski Areas ◽  
Clustered Distributions

<p>The development of ski areas would bring socio-economic benefits to mountain regions. At present, the ski industry in China is developing rapidly, and the number of ski areas is increasing dramatically. However, the understanding of the spatial pattern and driving factors for these ski areas is limited. This study collected detailed data about ski areas and their surrounding natural and economic factors in China. Criteria for classification of ski areas were proposed, and a total of 589 alpine ski areas in China were classified into three types: ski resorts for vacationing (va-ski resorts), ski areas for learning (le-ski areas) and ski parks to experience skiing (ex-ski parks), with proportions of 2.1%, 15.4% and 82.5%, respectively, which indicated that the Chinese ski industry was still dominated by small-sized ski areas. The overall spatial patterns of ski areas were clustered with a nearest neighbor indicator (NNI) of 0.424, in which ex-ski parks and le-ski areas exhibited clustered distributions with NNIs of 0.44 and 0.51, respectively, and va-ski resorts were randomly distributed with an NNI of 1.04. The theory and method of spatial autocorrelation were first used to analyze the spatial pattern and driving factors of ski areas. The results showed that ski areas in cities had a positive spatial autocorrelation with a Moran’s index value of 0.25. The results of Local Indications of Spatial Association (LISA) showed that ski areas were mainly concentrated in 3 regions: the Beijing-centered Yanshan-Taihang Mountains and Shandong Hill areas, the Harbin-centered Changbai Mountain areas and the Urumqi-centered Tianshan-Altay Mountain areas. The first location was mainly driven by socio-economic factors, and the latter two locations were mainly driven by natural factors. Ski tourism in China still faces many challenges. The government sector should strengthen supervision, develop a ski industry alliance, and promote the healthy and sustainable development of the ski industry in the future.</p>

scholarly journals Critical Dependence of Butterflies on a Non-native Host Plant in the Urban Tropics

2021 ◽  
Vol 9 ◽  
Author(s):  
Anuj Jain ◽  
Yiwen Zeng ◽  
Edward L. Webb
Keyword(s):  
Host Plant ◽  
Native Plants ◽  
Ecological Impacts ◽  
Tree Cover ◽  
Urban Habitat ◽  
Similar Species ◽  
Natural Habitats ◽  
Positive Dependence ◽  
Clustered Distributions ◽  
Native Host

Increasing urbanization in the tropics has led to the loss of natural habitats and local extirpations and the introduction of non-native plants in urban centers. Non-native plants can have widespread positive and negative ecological implications on native fauna including butterflies. In the small tropical urbanized city-state of Singapore, Aristolochia jackii (Aristolochiaceae), a native host plant of the nationally threatened Common Birdwing (Troides helena) and Common Rose (Pachliopta aristolochiae), is considered extirpated, but their shared non-native host plant Aristolochia acuminata is a cultivated ornamental in urban habitat. We conducted systematic surveys from years 2010 to 2014 and collated sighting records from 1999 to 2019 to map the distribution of T. helena and P. aristolochiae, and their host plant A. acuminata. We utilized machine learning models (i.e., random forest algorithms) to establish the relationships between various habitat (managed and natural tree cover, waterbody and impervious surface cover) and life-history parameters (minimum distance from the nearest larval host plant and population source derived from expert knowledge) that are associated with the butterfly distributions. Response curves were generated for each species and projected spatially across Singapore’s landscape to estimate occupancy. We found that both butterflies had clustered distributions with a greatly reduced probability of occurrence further away from identified population sources and non-native A. acuminata. Both study species had similar spatial niche and similar species occurrence responses though there were differences in habitat preferences and temporal niche. Both species showed positive dependence on managed tree cover (Rose more than Birdwing) but the Birdwing also had high positive dependence on natural tree cover, unlike the Rose. We report novel findings that a non-native host plant can provide positive ecological benefits and critically sustain tropical butterfly populations. While there will be a need to evaluate the full ecological impacts of non-native plantings, we suggest using them as a secondary strategy when re-establishment of the native plants has failed, particularly in highly urbanized tropical landscapes.

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