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Important Patterns (important + pattern)
Selected AbstractsCirculation dynamics of Mediterranean precipitation variability 1948,98INTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 15 2003A. Dünkeloh Abstract Canonical correlation analysis is used to identify main coupled circulation,rainfall patterns and to relate recent variability and trends of Mediterranean precipitation to large-scale circulation dynamics. Analyses are based on geopotential heights (500 and 1000 hPa levels) for the North Atlantic,European area (National Centers for Environmental Prediction,National Center for Atmospheric Research reanalysis) and on highly resolved (0.5° × 0.5° ) monthly rainfall grids (Climatic Research Unit, Norwich) selected for the Mediterranean area during the 1948,98 period. Combining monthly analyses with similar characteristics to seasonal samples yields winter (October,March), spring (April,May) and summer (June,September) types of coupled variability; a particular autumn type for the whole Mediterranean does not occur on the monthly time scale. Coupled patterns specifically linked to one or two seasons include an east Atlantic jet (EA-Jet) related pattern for summer and a Mediterranean meridional circulation (MMC) pattern for winter and spring. The most important pattern recurring with dynamical adjustments throughout the whole year reflects the seasonal cycle of the Mediterranean oscillation (MO), which is linked (with seasonal dependence) to the Northern Hemisphere teleconnection modes of the Arctic oscillation (AO) and North Atlantic oscillation (NAO). Winter rainfall trends of the recent decades marked by widespread decreases in the Mediterranean area and by opposite conditions in the southeastern part are linked to particular changes over time in several of the associated circulation patterns. Thus, different regional rainfall changes are integrated into an overall interrelation between Mediterranean rainfall patterns and large-scale atmospheric circulation dynamics. Copyright © 2003 Royal Meteorological Society [source] Spatial distributions of tree species in a subtropical forest of ChinaOIKOS, Issue 4 2009Lin Li The spatial dispersion of individuals in a species is an important pattern that is controlled by many mechanisms. In this study we analyzed spatial distributions of tree species in a large-scale (20 ha) stem-mapping plot in a species-rich subtropical forest of China. O-ring statistic was used to measure spatial patterns of species with abundance >10. ,0,10, the mean conspecific density within 10 m of a tree, was used as a measure of the intensity of aggregation of a species. Our results showed: (1) aggregated distribution was the dominant pattern in the plot. The percentage of aggregated species decreased with increased spatial scale. (2) The percentages of significantly aggregated species decreased from abundant to intermediate and to rare species. Rare species was more strongly aggregated than common species. Aggregation was weaker in larger diameter classes. (3) Seed traits determined the spatial patterns of trees. Seed dispersal mode can influence spatial patterns of species, with species dispersed by both modes being less clumped than species dispersed by animal or wind, respectively. Considering these results, we concluded that seed dispersal limitation, self-thinning and habitat heterogeneity primarily contributed to spatial patterns and species coexistence in the forest. [source] Differences between European and American IPO MarketsEUROPEAN FINANCIAL MANAGEMENT, Issue 4 2003Jay R. Ritter G24; G32; G14; G15 Abstract This brief survey discusses recent developments in the European initial public offering (IPO) market. The spectacular rise and fall of the Euro NM markets and the growth of bookbuilding as a procedure for pricing and allocating IPOs are two important patterns. Gross spreads are lower and less clustered than in the USA. Unlike the USA, some European IPOs, especially those in Germany, have when-issued trading prior to the final setting of the offer price. Current research includes empirical studies on the valuation of IPOs and both theoretical and empirical work on the determinants of short-run underpricing. [source] DIFFERENTIAL PATTERNS OF INTROGRESSION ACROSS THE X CHROMOSOME IN A HYBRID ZONE BETWEEN TWO SPECIES OF HOUSE MICEEVOLUTION, Issue 9 2004Bret A. Payseur Abstract A complete understanding of the speciation process requires the identification of genomic regions and genes that confer reproductive barriers between species. Empirical and theoretical research has revealed two important patterns in the evolution of reproductive isolation in animals: isolation typically arises as a result of disrupted epistatic interactions between multiple loci and these disruptions map disproportionately to the X chromosome. These patterns suggest that a targeted examination of natural gene flow between closely related species at X-linked markers with known positions would provide insight into the genetic basis of speciation. We take advantage of the existence of genomic data and a well-documented European zone of hybridization between two species of house mice, Mus domesticus and M. musculus, to conduct such a survey. We evaluate patterns of introgression across the hybrid zone for 13 diagnostic X-linked loci with known chromosomal positions using a maximum likelihood model. Interlocus comparisons clearly identify one locus with reduced introgression across the center of the hybrid zone, pinpointing a candidate region for reproductive isolation. Results also reveal one locus with high frequencies of M. domesticus alleles in populations on the M. musculus side of the zone, suggesting the possibility that positive selection may act to drive the spread of alleles from one species on to the genomic background of the other species. Finally, cline width and cline center are strongly positively correlated across the X chromosome, indicating that gene flow of the X chromosome may be asymmetrical. This study highlights the utility of natural populations of hybrids for mapping speciation genes and suggests that the middle of the X chromosome may be important for reproductive isolation between species of house mice. [source] Robust hierarchical state,space models reveal diel variation in travel rates of migrating leatherback turtlesJOURNAL OF ANIMAL ECOLOGY, Issue 5 2006IAN D. JONSEN Summary 1Biological and statistical complexity are features common to most ecological data that hinder our ability to extract meaningful patterns using conventional tools. Recent work on implementing modern statistical methods for analysis of such ecological data has focused primarily on population dynamics but other types of data, such as animal movement pathways obtained from satellite telemetry, can also benefit from the application of modern statistical tools. 2We develop a robust hierarchical state,space approach for analysis of multiple satellite telemetry pathways obtained via the Argos system. State,space models are time-series methods that allow unobserved states and biological parameters to be estimated from data observed with error. We show that the approach can reveal important patterns in complex, noisy data where conventional methods cannot. 3Using the largest Atlantic satellite telemetry data set for critically endangered leatherback turtles, we show that the diel pattern in travel rates of these turtles changes over different phases of their migratory cycle. While foraging in northern waters the turtles show similar travel rates during day and night, but on their southward migration to tropical waters travel rates are markedly faster during the day. These patterns are generally consistent with diving data, and may be related to changes in foraging behaviour. Interestingly, individuals that migrate southward to breed generally show higher daytime travel rates than individuals that migrate southward in a non-breeding year. 4Our approach is extremely flexible and can be applied to many ecological analyses that use complex, sequential data. [source] Remitting the gift: Zambian mobility and anthropological insights for migration studiesPOPULATION, SPACE AND PLACE (PREVIOUSLY:-INT JOURNAL OF POPULATION GEOGRAPHY), Issue 1 2005Lisa Cliggett Abstract This article brings together anthropological theories of gift exchange and ethnographic data on migrant gifting (,remitting') in order to understand the core of investing in social relations through remitting practices. Migration literature from throughout the developing world documents important patterns of remitting that furthers our understanding of how migrants' earnings help rural investment. In contrast to the majority of migration literature, scholars working in different regions of Zambia have documented migration patterns and remittance practices that do not echo the documented findings from other regions of the developing world. In Zambian migration, remittances consist more of food, ,town goods' or cash, rather than the larger sums of money or durable goods that other migration studies describe. The Zambian literature also documents cases of non-remitting. Rather than provide significant support to relatives in sending communities, Zambian migrants invest in social networks over time through ,gift-remitting'. These ,gift-remittances' facilitate options to return to home communities, or to maintain mutually beneficial social ties for both migrants and relatives in home villages. These findings compel policies directed towards enhancing migrants' remitting power to consider the core social foundation of their ties to home, and how investing in social relations can be incorporated into policy development. The article draws on fieldwork with the Gwembe Tonga people of Zambia's Southern Province since 1994, and recent ethnographic literature from Zambia. Copyright © 2005 John Wiley & Sons, Ltd. 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