Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “spatial patterning”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 397 records · Page 22Linked to original sources
PubMed1999

Temporal and spatial patterns of malaria reinfection in northeastern Venezuela.

We stratified the risk of malaria transmission (Plasmodium vivax) in 35 villages along a coastal range in northeastern Venezuela (51 km2) where the main vector is the mosquito Anopheles aquasalis. After 20 years without local malaria transmission, reinfection of the entire area occurred from May to December 1985 by local (continuous) and jump (discontinuous) dispersal. Epidemiologic, environmental, and vector variables were investigated with the aid of a Geographic Information System. Risk factors for malaria transmission were human population density, proximity to pre-adult mosquito habitats (< 500 m), and the number of pre-adult habitats nearby. Most inhabitants, immature mosquito habitats, and malaria cases were located at low elevations and on gentle slopes. High prevalence of malaria during the dry seasons was associated with the presence of permanent bodies of water containing An. aquasalis. Occurrence of a La Niña event in 1988 (wet and cool phase of the El Niño Southern Oscillation) triggered malaria transmission to unusually high levels, consolidating infection in the area, and rendering traditional control efforts useless. We recommend tracking malaria persistence per village and associated risk factors as methods to reduce the cost of malaria control programs.

Adolescent↗
PubMedDate not supplied

Spatial patterns of out-migration in Maharashtra: 1961-71.

In view of the importance of migration in Maharashtra state. India an attempt is made to identify the areas of out-migration, and to assess the probable causes for it. The analysis is confined to the decade 1961-1971 and based on secondary data, with the taluka as the unit of analysis. The total number of births and deaths in each taluka for the period of study was complied and enabled the natural increase of population to be computed. A comparison of this with the actual increase as indicated by the census made it possible to identify the areas of out-migration. The study revealed that the out-migration talukas were located in 3 areas and that the relative significance of out-migration varied. The analysis indicated that the causes of out-migration were probably unfavorable relief efforts, susceptibility to drought, closure of household industries, and the 'pull' effect of metropolitan centers like Bombay.

Asia↗
PubMedDate not supplied

Spatial pattern of migration of plantation labour and its dynamics.

"This study examines the issue of migration trends being witnessed by areas of plantation agriculture [in India]. The focus is on the linkages between structural changes in local economies, the overall development policy and people's responses to plantation agriculture both as an economic activity and as a way of life. Based on field data, it is a case study of Hassan district, Karnataka."

Agriculture↗
PubMed1992

Population change in the Republic of Ireland 1981-1991: trends and spatial patterns.

"Demographic trends in the Republic of Ireland have gradually moved closer to Western European norms during the past two decades. Birth rates have continued to fall and internal migration flows have become diversified. External migration has continued to play an important role in population change, however, and in the most recent census period has contributed to net decline. Geographical patterns of change within the state reflect a concentration of growth in the environs of the larger centres of population." (SUMMARY IN FRE)

Demography↗
PubMed1991

Temporal and spatial patterns of geographically indirect immigration to the United States.

"This article examines the little-studied phenomenon of indirect geographic migration to the United States, or the movement of persons whose country of last permanent residence differed from their country of birth. Over 8 million records of legal immigrants to the United States were studied for the period 1972-1987. Geographically indirect migration is shown to be important, amounting to as many as 86,136 persons during a single year. Primarily because of the dislocations of Southeast Asian refugees from their homelands and their subsequent admittance to the United States, indirect immigration increased during the 1980s. Moreover, again somewhat due to refugees, the patterns of geographically indirect movement changed during recent years. Political conditions in countries of birth appear to be important in explaining these patterns, as well as the age and skills of the indirect migrants themselves."

Age Factors↗
PubMed1992

The spatial pattern of international labour flows from and to Pakistan: a preliminary analysis.

"This paper attempts to identify the international labour flows of Pakistinis focussing on their geographical distribution. Based on a survey conducted by the Overseas Pakistanis Foundation and the Population Census of 1981 the study suggests that less developed districts are characterised by low out-migration and high return-migration. In addition, structural characteristics (e.g., land tenure) may be important in explaining low mobility from some underdeveloped districts...."

Asia↗
PubMed1992

Nucleoli and AgNOR proteins in 32 cases of primary breast carcinoma. Spatial pattern of interactions between 50 clinical and histometric criteria.

The purpose of this paper is to analyze a method allowing selection of the best morphometric criterion for quantifying AgNOR proteins under conventional observation conditions by light microscopy. We determined 50 parameters for 32 cases of primary breast carcinoma. For each case, three 100-nucleus samples (tumor center and periphery on a Giemsa-stained, 3-microns tumor section, periphery on a silver-stained section) were quantified. Distribution-free multidimensional data analysis was used to explore the geometric significance of the coefficient of correlation. This analysis revealed a clinical message linked with the largest "nucleolar structure" (nucleolus or AgNOR clump) per nucleus on the tumor periphery. Tumor recurrence or death correlated only with the coefficient of variation of the "nucleolar/nuclear" ratio of the greatest clump of AgNORs per nucleus periphery (CVRSa). The prognostic value of CVRSa is independent of that of conventional criteria, such as age, tumor size, Scarff-Bloom-Richardson grading and lymph node status. The largest AgNOR clump per nucleus may prove to be a further practical prognostic predictor.

Biometry↗
PubMed1985

Detection and characterization of spatial pattern in chimaeric tissue.

The mosaic pattern of patches of crypts of Lieberkühn in chimaeric C57BL/6JLac (B6)----DDK mouse small intestine, demonstrated using Dolichos biflorus agglutinin as strain-specific marker, is quantitatively examined using the Greig-Smith analysis of variance. This analysis, widely used in ecological research, provides a method to detect and characterize pattern at various scales. The analysis demonstrates that B6 patches are non-randomly distributed at all scales examined. A consistent increase in the intensity of pattern at one particular scale over all replicate samples identifies 'clusters of clusters' which probably are territories of 'descendent' clones. The sizes of descendent clones, either in terms of numbers of patches or total numbers of crypts, are highly variable. A steady reduction in the strength of pattern from proximal to distal is found. The Greig-Smith analysis of variance provides a valuable method for the analysis of pattern in chimaeric tissue.

Analysis of Variance↗
PubMed1978

Temporal and spatial patterns of the synthesis of tissue-specific polypeptides in the preimplantation mouse embryo.

Mouse embryos at different morphological stages in the transition from morula to blastocyst were analysed for the qualitative pattern of their polypeptide synthesis. The first appearance of the individual species of polypeptides specific to trophectoderm or ICM occurred progressively over this developmental period. Populations of inside cells recovered from morulae and early blastocysts synthesized those polypeptides previously shown to be characteristic of ICMs at 31/2 days, but not those characteristic of trophectoderm.

Animals↗