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Patterns
Kinds of Patterns Terms modified by Patterns Selected AbstractsMAY ISSUE VERSUS SHALL ISSUE: EXPLAINING THE PATTERN OF CONCEALED-CARRY HANDGUN LAWS, 1960,2001CONTEMPORARY ECONOMIC POLICY, Issue 2 2008RICHARD S. GROSSMAN We analyze the timing and pattern of adoption of "shall issue" concealed-carry handgun laws. "Shall issue" laws require the authorities to issue permits to qualified applicants; "may issue" laws give the authorities more latitude to reject applications. We find three factors influence the shift from "may issue" to "shall issue." First, more urban states are less likely to shift to "shall issue," although the size of this effect is quantitatively small. Second, the switch is influenced by the decisions taken by neighboring states. Third, we find evidence that increases in the crime rate accelerated the switch to "shall issue."(JEL K40) [source] CHANGING PATTERN OF CORPORATE GOVERNANCE AND FINANCING IN THE KOREAN CHAEBOLSECONOMIC PAPERS: A JOURNAL OF APPLIED ECONOMICS AND POLICY, Issue 3 2007BYUNG S. MIN The de jure financial system in Korea has moved from mainly R (relationship)-mode financial contracts towards M (market)-mode contracts since the 1997 financial crisis, due largely to reforms introducing Anglo-American style corporate governance and the disintermediation of the larger business groups in corporate financing. Analysis shows that the effectiveness of this change in improving firms' performances has yet to be demonstrated. Unlike the disintermediation of the big-name firms, the affiliates of small and medium business groups and small and medium-sized independent firms have relied heavily on bank loans and internal finance. The impact of a more concentrated banking system and intensified competition on the type of corporate investment has yet to be analysed. [source] THE GEOGRAPHICAL PATTERN OF SPECIATION AND FLORAL DIVERSIFICATION IN THE NEOTROPICS: THE TRIBE SINNINGIEAE (GESNERIACEAE) AS A CASE STUDYEVOLUTION, Issue 7 2007Mathieu Perret The geographical pattern of speciation and the relationship between floral variation and species ranges were investigated in the tribe Sinningieae (Gesneriaceae), which is found mainly in the Atlantic forests of Brazil. Geographical distribution data recorded on a grid system of 0.5 × 0.5 degree intervals and a near-complete species-level phylogenetic tree of Sinningieae inferred from a simultaneous analysis of seven DNA regions were used to address the role of geographical isolation in speciation. Geographical range overlaps between sister lineages were measured across all nodes in the phylogenetic tree and analyzed in relation to relative ages estimated from branch lengths. Although there are several cases of species sympatry in Sinningieae, patterns of sympatry between sister taxa support the predominance of allopatric speciation. The pattern of sympatry between sister taxa is consistent with range shifts following allopatric speciation, except in one clade, in which the overlapping distribution of recent sister species indicates speciation within a restricted geographical area and involving changes in pollinators and habitats. The relationship between floral divergence and regional sympatry was also examined by analyzing floral contrasts, phenological overlap, and the degree of sympatry between sister clades. Morphological contrast between flowers is not increased in sympatry and phenological divergence is more apparent between allopatric clades than between sympatric clades. Therefore, our results failed to indicate a tendency for sympatric taxa to minimize morphological and phenological overlap (geographic exclusion and/or character displacement hypotheses). Instead, they point toward adaptation in phenology to local conditions and buildup of sympatries at random with respect to flower morphology. Additional studies at a lower geographical scale are needed to identify truely coexisting species and the components of their reproductive isolation. [source] THE PHYLOGENETIC PATTERN OF SPECIATION AND WING PATTERN CHANGE IN NEOTROPICAL ITHOMIA BUTTERFLIES (LEPIDOPTERA: NYMPHALIDAE)EVOLUTION, Issue 7 2006Chris D. Jiggins Abstract Species level phylogenetic hypotheses can be used to explore patterns of divergence and speciation. In the tropics, speciation is commonly attributed to either vicariance, perhaps within climate-induced forest refugia, or ecological speciation caused by niche adaptation. Mimetic butterflies have been used to identify forest refugia as well as in studies of ecological speciation, so they are ideal for discriminating between these two models. The genus Ithomia contains 24 species of warningly colored mimetic butterflies found in South and Central America, and here we use a phylogenetic hypothesis based on seven genes for 23 species to investigate speciation in this group. The history of wing color pattern evolution in the genus was reconstructed using both parsimony and likelihood. The ancestral pattern for the group was almost certainly a transparent butterfly, and there is strong evidence for convergent evolution due to mimicry. A punctuationist model of pattern evolution was a significantly better fit to the data than a gradualist model, demonstrating that pattern changes above the species level were associated with cladogenesis and supporting a model of ecological speciation driven by mimicry adaptation. However, there was only one case of sister species unambiguously differing in pattern, suggesting that some recent speciation events have occurred without pattern shifts. The pattern of geographic overlap between clades over time shows that closely related species are mostly sympatric or, in one case, parapatric. This is consistent with modes of speciation with ongoing gene flow, although rapid range changes following allopatric speciation could give a similar pattern. Patterns of lineage accumulation through time differed significantly from that expected at random, and show that most of the extant species were present by the beginning of the Pleistocene at the latest. Hence Pleistocene refugia are unlikely to have played a major role in Ithomia diversification. [source] TEMPORAL PATTERN OF AFRICANIZATION IN A FERAL HONEYBEE POPULATION FROM TEXAS INFERRED FROM MITOCHONDRIAL DNAEVOLUTION, Issue 5 2004M. Alice Pinto Abstract The invasion of Africanized honeybees (Apis mellifera L.) in the Americas provides a window of opportunity to study the dynamics of secondary contact of subspecies of bees that evolved in allopatry in ecologically distinctive habitats of the Old World. We report here the results of an 11-year mitochondrial DNA survey of a feral honeybee population from southern United States (Texas). The mitochondrial haplotype (mitotype) frequencies changed radically during the 11-year study period. Prior to immigration of Africanized honeybees, the resident population was essentially of eastern and western European maternal ancestry. Three years after detection of the first Africanized swarm there was a mitotype turnover in the population from predominantly eastern European to predominantly A. m. scutellata (ancestor of Africanized honeybees). This remarkable change in the mitotype composition coincided with arrival of the parasitic mite Varroa destructor, which was likely responsible for severe losses experienced by colonies of European ancestry. From 1997 onward the population stabilized with most colonies of A. m. scutellata maternal origin. [source] COEVOLUTION OF COLOR PATTERN AND THERMOREGULATORY BEHAVIOR IN POLYMORPHIC PYGMY GRASSHOPPERS TETRIX UNDULATAEVOLUTION, Issue 2 2002Anders Forsman Abstract Ectothermic organisms, such as insects and reptiles, rely on external heat sources to control body temperature and possess physiological and behavioral traits that are temperature dependent. It has therefore been hypothesised that differences in body temperature resulting from phenotypic properties, such as color pattern, may translate into selection against thermally inferior phenotypes. We tested for costs and benefits of pale versus dark coloration by comparing the behaviors (i.e., basking duration and bouts) of pygmy grasshopper (Tetrix undulata) individuals exposed to experimental situations imposing a trade-off between temperature regulation and feeding. We used pairs consisting of two full-siblings of the same sex that represented different (genetically coded) color morphs but had shared identical conditions from the time of fertilization. Our results revealed significant differences in behavioral thermoregulation between dark and pale individuals in females, but not in males. Pale females spent more time feeding than dark females, regardless of whether feeding was associated with a risk of either hypothermia or overheating. In contrast, only minor differences in behavior (if any) were evident between individuals that belonged to the same color morph but had been painted black or gray to increase and decrease their heating rates. This suggests that the behavioral differences between individuals belonging to different color morphs are genetically determined, rather than simply reflecting a response to different heating rates. To test for effects of acclimation on behaviors, we used pairs of individuals that had been reared from hatchlings to adults under controlled conditions in either low or high temperature. The thermal regime experienced during rearing had little effect on behaviors during the experiments reported above, but significantly influenced the body temperatures selected in a laboratory thermal gradient. In females (but not in males) preferred body temperature also varied among individuals born to mothers belonging to different color morphs, suggesting that a genetic correlation exists between color pattern and temperature preferences. Collectively, these findings, at least in females, are consistent with the hypothesis of multiple-trait coevolution and suggest that the different color morphs represent alternative evolutionary strategies. [source] ANALYSIS ON THE DYNAMICS OF SPATIAL DISTRIBUTION PATTERN OF MIXED SPIDER POPULATION IN RICE FIELDINSECT SCIENCE, Issue 4 2004Zhi Wang Abstract The results make it clear that there are total 11 families, 29 genera and 43 species of spiders in the rice field of Dong Fang Hong Farm. Among them, there are 8 families, 19 genera and 28 species in the early rice field, and 10 families, 27 genera and 36 species in the late rice field. The spatial distribution pattern of mixed spider populations in rice fields was different during different development stages of rice plant. During the prophase, metaphase and anaphase of early rice plant development, the spatial distribution pattern of mixed spider populations was aggregative, random and aggregative respectively. During the prophase, metaphase and anaphase of late rice plant development, the spatial distribution pattern was uniform, aggregative and uniform respectively. [source] HISTOPATHOLOGICAL PATTERN OF GASTRIC BIOPSIES OF HELICOBACTER PYLORI POSITIVE PATIENTS IN SARDJITO GENERAL HOSPITAL, YOGYAKARTA, INDONESIAJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 12 2000Siti Nurdjanah Objective: To determine the gastric histopathological types distribution of H. pylori positive patients who were detected histopathologically. Material& Methods: Study design was prospective study. Consecutive patients who were suffering chronic dyspepsia underwent endoscopy examination between August 1998 and December 1999. The biopsy specimens were taken from gastric antrum and corpus and sent to the pathologist for histopathology type and H. pylori examinations. H. pylori were also confirmed with CLO and IgG-Helicobacter pylori tests. Results: There were 92 patients (48 male (M) and 44 Female (F) who underwent gastric biopsies endoscopically between August 1998 and December 1999. Fifty-six (60.87%) patients were chronic superficial gastritis, 11(11.96%) chronic antropic gastritis, 18 (19.56%) chronic gastritis 2 (2.17%) chronic gastritis with metaplasia, 3 (3.27%) gastric ulcer, and 2 (2.17%) gastric signet-ring cell carcinoma. Twenty one (22.8%) patients with H. pylori positive by histopathology examination with CLO and IgG-H.pylori tests. Those were 5 (8.90%) patients with chronic superficial gastritis, 7(63.63%) chronic atrophic gastritis, 3(100%) gastric ulcer, 2 (100%) chronic gastritis with metaplasia, 3(16.67%) chronic gastritis, 1(50%) signet-ring cell carcinoma. The age range of the H. pylori positive patients were between 16 and 76 years old. Conclusion: Twenty one (22.8%) H. pylori positive patients out of 92 endoscopied patients and the high percentage tendency of H. pylori positively in chronic atrophic gastritis, gastric ulcer, and chronic gastritis with metaplasia, although most of the patients had chronic superficial gastritis. Further study is needed with larger with larger sample to get the clearer picture of H. pylori distribution based on gastric histopathological types. [source] REDOX PROPERTIES ARE CONSERVED IN RUBISCOS FROM DIATOMS AND GREEN ALGAE THROUGH A DIFFERENT PATTERN OF CYSTEINES,JOURNAL OF PHYCOLOGY, Issue 3 2010Julia Marín-Navarro Eukaryotic RUBISCO appears in two sequence-diverging forms, known as red-like (present in nongreen algae) and green-like (of green algae and higher plants) types. Oxidation of cysteines from green-like RUBISCOs is known to result in conformational changes that inactivate the enzyme and render a relaxed structure more prone to proteolytic attack. These changes may have regulatory value for green algae and higher plants, promoting RUBISCO catabolism under stress conditions. We compare here red-like RUBISCOs from several diatoms with a representative green-like RUBISCO from Chlamydomonas reinhardtii, paying special attention to the cysteine-dependent redox properties. Purified diatom RUBISCO preparations displayed a specific carboxylase activity about one order of magnitude lower than that of the C. reinhardtii P. A. Dang. enzyme. Despite having different patterns of cysteine residues in their primary sequence, the red-like enzymes from diatoms inactivated also through oxidation of cysteine sulfhydryls to disulfides with a transition midpoint identical to that of the green-like forms. Cysteine oxidation resulted also in structural modifications of the diatom RUBISCOs, as recognized by a higher sensitivity of the oxidized enzyme to in vitro proteolysis. The coincident redox properties of red- and green-like RUBISCO types suggest that these changes are part of a physiologically significant regulatory mechanism that has been convergently implemented in both groups with a different set of cysteine residues. [source] EARLY DEVELOPMENT PATTERN OF THE BROWN ALGA ECTOCARPUS SILICULOSUS (ECTOCARPALES, PHAEOPHYCEAE) SPOROPHYTE,JOURNAL OF PHYCOLOGY, Issue 5 2008Aude Le Bail The distant phylogenetic position of brown macroalgae from the other multicellular phyla offers the opportunity to study novel and alternative developmental processes involved in the establishment of multicellularity. At present, however, very little information is available about developmental patterning in this group. Ectocarpus siliculosus (Dillwyn) Lyngb. has uniseriate filaments and displays one of the simplest architectures in the Phaeophyceae. The aim of this study was to decipher the morphogenetic steps that lead to the development of the Ectocarpus sporophyte. We carried out a detailed morphometric study of the events that occurred between gamete germination and the 100-cell stage. This analysis was performed on two ecologically distant isolates to assess plasticity in developmental patterning within this species. Cell sizes were measured in both isolates, allowing the definition of two main cell types based on their shape (round and elongated). On average, the filament is composed of about 40% round cells, which are present in the central region of the filament, but different combinations of the two cell types within filaments were observed and quantified. Young sporophytes grew apically, with elongated cells progressively differentiating into round cells. Secondary filaments emerged preferentially on round cells, primarily from the older central cells. Statistical analyses showed that the pattern of branching was regulated to ensure a stereotyped architecture. This description of the developmental patterning during the growth of the E. siliculosus sporophyte will serve as a base for more detailed studies of development, in this species and in brown algae in general. [source] DETECTION OF LOCAL INTERACTIONS FROM THE SPATIAL PATTERN OF NAMES IN FRANCE,JOURNAL OF REGIONAL SCIENCE, Issue 1 2008Keith Head ABSTRACT Using data on the geographic distribution of names in France, we investigate the social transmission of parental preferences. Drawing on recent work on nonmarket interactions, we develop a linear discrete choice model that relates choices made in one location to those made in nearby areas. We explain the shares of parents that give their children Saint, Arabic, and American-type names. We also examine the effect of distance between locations on differences in naming patterns. We find that the importance of geographic distance is declining over time while differences in class and national origins have increasing explanatory power. [source] MONOPOLISTIC COMPETITION WITH EFFICIENCY GAPS AND A HECKSCHER-OHLIN TRADE PATTERN,THE JAPANESE ECONOMIC REVIEW, Issue 3 2006TORU KIKUCHI We develop a two-factor, three-sector model of international trade in which the monopolistically competitive firms are characterized by different fixed production costs. We show that, depending on the pattern of the international distribution of factor endowments, the trade pattern is determined not only by relative factor endowments as suggested by Heckscher and Ohlin, but also by absolute factor endowments via a mechanism of competitive selection in the monopolistically competitive sector. [source] THE PATTERN AND EVOLUTION OF GEOGRAPHICAL WAGE DIFFERENTIALS IN THE PUBLIC AND PRIVATE SECTORS IN GREAT BRITAIN,THE MANCHESTER SCHOOL, Issue 4 2007DAVID BELL Government policy on the nature of wage bargaining in the public sector can have important implications for the provision of public services. Using the New Earnings Survey, the Labour Force Survey and the British Household Panel Survey, we examine the size and evolution of public,private sector wage differentials across geographical areas within the UK and over time. Public sector bargaining structures have led to historically high wage premia, although these premia are declining over time. In high-cost low-amenity areas, such as the south-east of England, the public sector underpays relative to the private sector, therefore creating problems in recruitment to and provision of public services. Public sector labour markets are around 40 per cent as responsive to area differences in amenities and costs as are private sector labour markets. Differences in the degree of spatial variation between sectors are likely to remain, leading to persistent problems for the delivery of public services in some parts of the UK. Reform of public sector pay structures is likely to be costly, and so other non-pay policies need to be considered to increase the attractiveness of public sector jobs. [source] THE APPLE DOESN'T FALL FAR FROM THE TREE (OR DOES IT?): INTERGENERATIONAL PATTERNS OF ANTISOCIAL BEHAVIOR,THE AMERICAN SOCIETY OF CRIMINOLOGY 2008 SUTHERLAND ADDRESS,CRIMINOLOGY, Issue 2 2009TERENCE P. THORNBERRY There is a growing literature on intergenerational studies of antisocial behavior and a growing understanding of the unique contributions they are likely to make. At the same time, the field has yet to agree on core design features for intergenerational study. In this article, I propose a set of defining design elements that all intergenerational studies should meet and I discuss the advantages of these studies for enhancing our understanding of the onset and course of delinquent careers. I then use data from the ongoing Rochester Intergenerational Study to illustrate these points and the potential yield of intergenerational studies. In particular, I examine intergenerational continuities in antisocial behavior and school disengagement, test the cycle of violence hypothesis to see whether a history of maltreatment increases the likelihood of perpetration of maltreatment, and estimate a structural equation model to help identify mediating pathways that link parents and children with respect to antisocial behavior. [source] MICROVASCULAR PATTERNS OF ESOPHAGEAL MICRO SQUAMOUS CELL CARCINOMA ON MAGNIFYING ENDOSCOPYDIGESTIVE ENDOSCOPY, Issue 1 2008Hideaki Arima Background:, Recently, esophageal microcancers have been frequently diagnosed and are receiving increasing attention as initial findings of cancer. We examined whether the clinicopathological features and microvascular patterns of esophageal microcancers on magnifying endoscopy are useful for diagnosis. Methods:, Magnifying endoscopy was performed to examine the histopathological features of 55 esophageal cancers measuring ,10 mm in diameter (34 small cancers, 16 microcancers, and five supermicrocancers). Results:, Although some lesions were detected only on iodine staining, most were detected on conventional endoscopic examination. Most small cancers and microcancers were m1 or m2; some were m3 or sm2. Supermicrocancers were dysplasia or m1 cancer. As for the microvascular pattern, most m1 and m2 cancers showed type 3 vessels, while most submucosal cancers showed type 4 vessels. Conclusions:, Microvascular patterns on magnifying endoscopy are useful for the differential diagnosis of benign and malignant esophageal cancers and for estimating the depth of tumor invasion. The shape of small lesions is often altered considerably by biopsy. Residual tumor may persist unless the basal layer of the lesion is included in biopsy specimens, even in microcancers. Consequently, endoscopic mucosal resection, without biopsy, is being performed in increasing numbers of patients with lesions suspected to be cancer on the basis of their microvascular patterns. [source] IDENTIFYING COEVOLUTIONARY PATTERNS IN HUMAN LEUKOCYTE ANTIGEN (HLA) MOLECULESEVOLUTION, Issue 5 2010Xiaowei Jiang The antigenic peptide, major histocompatibility complex molecule (MHC; also called human leukocyte antigen, HLA), coreceptor CD8, or CD4 and T-cell receptor (TCR) function as a complex to initiate effectors' mechanisms of the immune system. The tight functional and physical interaction among these molecules may have involved strong coevolution links among domains within and between proteins. Despite the importance of unraveling such dependencies to understand the arms race of host,pathogen interaction, no previous studies have aimed at achieving such an objective. Here, we perform an exhaustive coevolution analysis and show that indeed such dependencies are strongly shaping the evolution and probably the function of these molecules. We identify intramolecular coevolution in HLA class I and II at domains important for their immune activity. Most of the amino acid sites identified to be coevolving in HLAI have been also detected to undergo positive Darwinian selection highlighting therefore their adaptive value. We also identify coevolution among antigen-binding pockets (P1-P9) and among these and TCR-binding sites. Conversely to HLAI, coevolution is weaker in HLAII. Our results support that such coevolutionary patterns are due to selective pressures of host,pathogen coevolution and cooperative binding of TCRs, antigenic peptides, and CD8/CD4 to HLAI and HLAII. [source] A TEST AND REVIEW OF THE ROLE OF EFFECTIVE POPULATION SIZE ON EXPERIMENTAL SEXUAL SELECTION PATTERNSEVOLUTION, Issue 7 2009Rhonda R. Snook Experimental evolution, particularly experimental sexual selection in which sexual selection strength is manipulated by altering the mating system, is an increasingly popular method for testing evolutionary theory. Concerns have arisen regarding genetic diversity variation across experimental treatments: differences in the number and sex ratio of breeders (effective population size; Ne) and the potential for genetic hitchhiking, both of which may cause different levels of genetic variation between treatments. Such differences may affect the selection response and confound interpretation of results. Here we use both census-based estimators and molecular marker-based estimates to empirically test how experimental evolution of sexual selection in Drosophila pseudoobscura impacts Ne and autosomal genetic diversity. We also consider effects of treatment on X-linked Nes, which have previously been ignored. Molecular autosomal marker-based estimators indicate that neither Ne nor genetic diversity differs between treatments experiencing different sexual selection intensities; thus observed evolutionary responses reflect selection rather than any confounding effects of experimental design. Given the increasing number of studies on experimental sexual selection, we also review the census Nes of other experimental systems, calculate X-linked Ne, and compare how different studies have dealt with the issues of inbreeding, genetic drift, and genetic hitchhiking to help inform future designs. [source] TOWARD THE EVOLUTIONARY GENOMICS OF GAMETOPHYTIC DIVERGENCE: PATTERNS OF TRANSMISSION RATIO DISTORTION IN MONKEYFLOWER (MIMULUS) HYBRIDS REVEAL A COMPLEX GENETIC BASIS FOR CONSPECIFIC POLLEN PRECEDENCEEVOLUTION, Issue 12 2008Lila Fishman Conspecific pollen precedence (CPP) is a major component of reproductive isolation between many flowering plant taxa and may reveal mechanisms of gametophytic evolution within species, but little is known about the genetic basis and evolutionary history of CPP. We systematically investigated the genetic architecture of CPP using patterns of transmission ratio distortion (TRD) in F2 and backcross hybrids between closely related species of Mimulus (Phrymaceae) with divergent mating systems. We found that CPP in Mimulus hybrids was polygenic and was the majority source of interspecific TRD genome-wide, with at least eight genomic regions contributing to the transmission advantage of M. guttatus pollen grains on M. guttatus styles. In aggregate, these male-specific transmission ratio distorting loci (TRDLs) were more than sufficient to account for the 100% precedence of pure M. guttatus pollen over M. nasutus pollen in mixed pollinations of M. guttatus. All but one of these pollen TRDLs were style-dependent; that is, we observed pollen TRD in F1 and/or M. guttatus styles, but not in M. nasutus styles. These findings suggest that species-specific differences in pollen tube performance accumulate gradually and may have been driven by coevolution between pollen and style in the predominantly outcrossing M. guttatus. [source] EJACULATE DEPLETION PATTERNS EVOLVE IN RESPONSE TO EXPERIMENTAL MANIPULATION OF SEX RATIO IN DROSOPHILA MELANOGASTEREVOLUTION, Issue 8 2007Jon R. Linklater We assessed the extent to which traits related to ejaculate investment have evolved in lines of Drosophila melanogaster that had an evolutionary history of maintenance at biased sex ratios. Measures of ejaculate investment were made in males that had been maintained at male-biased (MB) and female-biased (FB) adult sex ratios, in which levels of sperm competition were high and low, respectively. Theory predicts that when the risk of sperm competition is high and mating opportunities are rare (as they are for males in the MB populations), males should increase investment in their few matings. We therefore predicted that males from the MB lines would (1) exhibit increased investment in their first mating opportunities and (2) deplete their ejaculates at a faster rate when mating multiply, in comparison to FB males. To investigate these predictions we measured the single mating productivity of males from three replicates each of MB and FB lines mated to five wild-type virgin females in succession. In contrast to the first prediction, there was no evidence for differences in productivity between MB and FB line males in their first matings. The second prediction was upheld: mates of MB and FB males suffered increasingly reduced productivity with successive matings, but the decline was significantly more pronounced for MB than for FB males. There was a significant reduction in the size of the accessory glands and testes of males from the MB and FB regimes after five successive matings. However, the accessory glands, but not testes, of MB males became depleted at a significantly faster rate than those of FB males. The results show that male reproductive traits evolved in response to the level of sperm competition and suggest that the ability to maintain fertility over successive matings is associated with the rate of ejaculate, and particularly accessory gland, depletion. [source] PATTERNS OF PHENOTYPIC AND GENETIC VARIATION FOR THE PLASTICITY OF DIAPAUSE INCIDENCEEVOLUTION, Issue 7 2007Wade E. Winterhalter Phenotypic plasticity describes an organism's ability to produce multiple phenotypes in direct response to its environmental conditions. Over the past 15 years empiricists have found that this plasticity frequently exhibits geographic variation and often possesses a significant heritable genetic basis. However, few studies have examined both of these aspects of plasticity simultaneously. Here, we examined both the geographic and genetic variations of the plasticity for diapause incidence (the proportion of eggs that enter an arrested state of development capable of surviving over the winter) relative to temperatures and photoperiods associated with long and short season environments across six populations of the striped ground cricket, Allonemobius socius, using a half-sibling split brood quantitative genetic design. We found that plasticity, as measured by the slope of the reaction norm, was greater in the southern-low altitude region (where populations are bivoltine) relative to the southern-high and northern-low altitude regions (where populations are univoltine). However, the heritability of plasticity was only significantly different from zero in univoltine populations that experienced "intermediate" natal season lengths. These patterns suggest that selection may favor the plasticity of diapause incidence in bivoltine regions, but act against plasticity in regions in which populations are univoltine. Furthermore, our data suggest that under "intermediate" natal season length conditions, the interplay between local adaptation and gene flow may keep the plasticity of diapause incidence low (but still significant) while maintaining its genetic variation. As such, this study not only provides a novel observation into the geographic variation of phenotypic plasticity, but also provides much needed groundwork for tests of its adaptive significance. [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] CONTEMPORARY PATTERNS IN A HISTORICAL CONTEXT: PHYLOGEOGRAPHIC HISTORY OF THE PIPEVINE SWALLOWTAIL, BATTUS PHILENOR (PAPILIONIDAE)EVOLUTION, Issue 5 2003James A. Fordyce Abstract We examined mitochondrial DNA (mtDNA) variation in pipevine swallowtail butterflies (Battus philenor) from throughout its extant range to provide a historical, phylogeographical context for ecological studies of the disjunct population in California. We evaluate current hypotheses regarding host plant use, behavior, and mimetic relationships of B. philenor populations and generate alternative hypotheses. Compared to populations throughout the rest of the species' range, California populations are ecologically distinct in that they lack mimics, lay significantly larger clutches of eggs, and exclusively use a unique, endemic larval host plant. Analysis of molecular variance, tests of population differentiation, and nested clade analysis of mtDNA variation indicate that, despite low levels of population genetic structure across the species' range, there is evidence of recent range expansion from presumed Pleistocene refuge(s) in southeastern North America. Colonization of California appears to have been a recent event. This phylogeographic investigation also suggests that the evolution of life-history adaptations to a novel larval host has occurred rapidly in California and the lack of mimics in California may be attributable to the recency of colonization. [source] RECONSTRUCTING PLUMAGE EVOLUTION IN ORIOLES (ICTERUS): REPEATED CONVERGENCE AND REVERSAL IN PATTERNSEVOLUTION, Issue 6 2000Kevin E. Omland Abstract. Several empirical studies suggest that sexually selected characters, including bird plumage, may evolve rapidly and show high levels of convergence and other forms of homoplasy. However, the processes that might generate such convergence have not been explored theoretically. Furthermore, no studies have rigorously addressed this issue using a robust phylogeny and a large number of signal characters. We scored the appearance of 44 adult male plumage characters that varied across New World orioles (Icterus). We mapped the plumage characters onto a molecular phylogeny based on two mitochondrial genes. Reconstructing the evolution of these characters revealed evidence of convergence or reversal in 42 of the 44 plumage characters. No plumage character states are restricted to any groups of species higher than superspecies in the oriole phylogeny. The high frequency of convergence and reversal is reflected in the low overall retention index (RI = 0.66) and the low overall consistency index (CI = 0.28). We found similar results when we mapped plumage changes onto a total evidence tree. Our findings reveal that plumage patterns and colors are highly labile between species of orioles, but highly conserved within the oriole genus. Furthermore, there are at least two overall plumage types that have convergently evolved repeatedly in the three oriole clades. This overall convergence leads to significant conflict between the molecular and plumage data. It is not clear what evolutionary processes lead to this homoplasy in individual characters or convergence in overall pattern. However, evolutionary constraints such as developmental limitations and genetic correlations between characters are likely to play a role. Our results are consistent with the belief that avian plumage and other sexually selected characters may evolve rapidly and may exhibit high homoplasy. The overall convergence in oriole plumage patterns is an interesting evolutionary phenomenon, but it cautions against heavy reliance on plumage characters for constructing phylogenies. [source] A CITY IN MOTION: TIME-SPACE ACTIVITY AND MOBILITY PATTERNS OF SUBURBAN INHABITANTS AND THE STRUCTURATION OF THE SPATIAL ORGANIZATION OF THE PRAGUE METROPOLITAN AREAGEOGRAFISKA ANNALER SERIES B: HUMAN GEOGRAPHY, Issue 2 2007Jakub Novák ABSTRACT. This contribution attempts to reveal the relations between new suburban areas and other parts of the Prague metropolitan area by investigating the time-space activity and mobility patterns of the inhabitants of newly built suburban districts. The focus on some aspects of the everyday life of people in new suburbs helps us to identify the impact of suburbanization on the changing geography of the metropolitan region and to better understand how the spatial organization of the Prague metropolitan area is produced, reproduced and transformed. We use several interrelated concepts, which serve the theoretical foundation of our work, namely time geography, structuration theory and the post-communist city. The empirical data utilized are primarily based on 262 diaries completed by eighty-eight individuals from thirty-eight households, accompanied by household questionnaires and interviews with the heads of households. The research confirmed the implicit, generally unspoken view that new suburbs in the Prague metropolitan region are heavily dependent on the core of the metropolitan area for the provision of jobs and services. However, newly built suburban shopping facilities to some extent disrupt this pattern, keeping some daily activities of inhabitants within the suburban zone. In addition to empirical observations, the key purpose of this contribution has been to discuss and apply time geography concepts and methods to the research of urban restructuring, and to understand the structuration of metropolitan spatial organization. [source] ASIANS IN AMERICA'S SUBURBS: PATTERNS AND CONSEQUENCES OF SETTLEMENT§GEOGRAPHICAL REVIEW, Issue 2 2005EMILY SKOP ABSTRACT. In an effort to provide a more complex and multifaceted understanding of the process of spatial assimilation, this article explores alternative paths in understanding racial/ ethnic minority residential patterns. It scrutinizes patterns of contemporary Asian Indian and Chinese settlement in two metropolitan areas: Austin, Texas and Phoenix, Arizona. Though not particularly evolved in terms of their Asian immigrant settlement or dynamics, Austin and Phoenix represent the growing number of newly emergent Asian centers throughout the nation that have developed with the rapid rise of immigration from these two countries in the past several decades. The analysis utilizes records from the 2000 census to document and map Asian Indian and Chinese settlement within each metropolitan area and to investigate whether-and to what degree-each group is clustered or dispersed. The article then raises important questions about the consequences of concentration and dispersal for the incorporation of Asian Indian and Chinese residents. [source] RELEVANT PATTERNS OF CHRISTIAN WITNESS IN PLURALISTIC SOCIETIES: AN INDIAN PERSPECTIVEINTERNATIONAL REVIEW OF MISSION, Issue 361 2002JESUDAS M. ATHYAL First page of article [source] EVALUATION OF SURVIVAL PATTERNS AND CELLULAR INJURY OF PSEUDOMONAS AERUGINOSA IN DIFFERENT BOTTLED WATERS STORED UNDER VARIOUS CONDITIONSJOURNAL OF FOOD SAFETY, Issue 3 2001PAULA TEIXEIRA ABSTRACT Pseudomonas aeruginosa cells were inoculated into different waters and sampled after different periods of starvation in order to evaluate the influences of storage under daylight or dark conditions, the presence or absence of the autochthonous flora, the chemical composition of the water and the storage temperature, on survival Survival was investigated by plate counts on selective and nonselective agar media. Light, low temperature (4C) and presence of the autochthonous flora negatively influenced the survival of P. aeruginosa during starvation in water. Higher survival rates were observed in waters with high mineral content. During starvation, cells developed sensitivity to the selective medium demonstrating that research is needed in the development of new media, or improvement in the existing ones, for the enumeration of P. aeruginosa in water. Current selective media/methodologies for detecting P. aeruginosa in mineral waters may seriously underestimate the levels of or presence of this organism which might represent, in some cases, a hazard to the public health. [source] THE EVOLUTION OF A MODEL TRAP IN THE CENTRAL APENNINES, ITALY: FRACTURE PATTERNS, FAULT REACTIVATION AND DEVELOPMENT OF CATACLASTIC ROCKS IN CARBONATES AT THE NARNI ANTICLINEJOURNAL OF PETROLEUM GEOLOGY, Issue 2 2001F. Storti Recent hydrocarbon discoveries in the Southern Apennines of Italy have focussed attention on the importance of studying fracturing and cataclasis in carbonate rocks because of their fundamental impact on reservoir permeability and connectivity. The Narni Anticline in the central Apennines consists of a stack of easterly-verging carbonate thrust sheets compartmentalized by extensional and strike-slip fault zones. The structure provides afield analogue for studying the evolution of superimposed fold- and fault-related fractures in carbonate reservoir rocks. The fracture pattern at the Narni Anticline developed as a result of three mechanisms: (a) layer-parallel shortening predating folding and faulting; (b) thrust-related folding and further thrust breakthrough; and (c) extensional and strike-slip faulting. Along-strike (longitudinal) fractures developed during progressive rollover fault-propagation folding, and their intensity depends on the precise structural position within the fold: fracture intensity is high in the forelimb and low in the crest. The 3-D architecture of the mechanical anisotropy associated with thrusting, folding, and related fracturing constrained the location and geometry of subsequent extensional and strike-slip faulting. The superimposition in damage zones of a fault-related cleavage on the pre-existing fracture pattern, which is associated with layer-parallel shortening and thrust-related folding, resulted in rock fragmentation and comminution, and the development of cataclastic bands. The evolution of fracturing in the Narni Anticline, its role in constraining thrust breakthrough trajectories and the location of extensional and strike-slip faults, and the final development of low-permeability cataclastic bands, will be relevant to studies of known oilfields in the Southern Apennines, as well as for future exploration. [source] INCREASED SAMPLING FOR INFERRING PHYLOGEOGRAPHIC PATTERNS IN BOSTRYCHIA RADICANS/B.JOURNAL OF PHYCOLOGY, Issue 6 2006MORITZIANA (RHODOMELACEAE, RHODOPHYTA) IN THE EASTERN USA Zuccarello and West (2003) reported on the phylogenetic diversity of algae identified as Bostrychia radicans (Montagne) Montagne and B. moritziana (Sonder ex Kützing) J. Agardh from around the world. They showed that the species complex consisted of seven distinct lineages, of which two lineages were common on the East Coast of the USA and eastern Gulf of Mexico. The distribution of haplotypes within these lineages on the East Coast of the USA showed a general north,south distribution. One haplotype of lineage 5 (B) was mostly collected in northern areas, while the other common haplotype (C) was more southerly in distribution. Samples in lineage 6 (haplotype D) were not found north of Sapelo Island, Georgia. Increased sampling from the eastern USA over 5 years later has revealed an altered pattern. Haplotype D is distributed in North Carolina and is common in some populations. Haplotype C is rare or absent in many sampled populations. Haplotype B is only observed in the northern sampled sites on both sides of the Florida peninsula. This disjunct distribution agrees with geological scenarios for a strait between the western Gulf of Mexico and southern Georgia in the Miocene/Pliocene, which closed in the late Pliocene. This paper highlights the importance of increased sampling to determine phylogeographic patterns and hypotheses of dispersal scenarios in algae. [source] PATTERNS OF INTERSPECIFIC INTERACTIONS IN THE ULVA -DOMINATED INTERTIDAL COMMUNITY IN A SOUTHERN COAST OF KOREAJOURNAL OF PHYCOLOGY, Issue 2000Y.J. Bhang In the southern coast of Korea, rocky intertidal zones where green tide commonly occurs are dominated by Ulva pertusa, red algal turf (a mixed stand of Gigartina intermedia and Gigartina teedii) and species of Enteromorpha with highly opportunistic occurrence. To investigate their interspecific interactions, a field experiment was carried out using press effect of one species removal from permanent plots (20 x 20cm) set up on two different tidal heights. Mechanisms of interaction were also attempted using artificial plants to test the possible effects of shading, scouring, allelopathy of U. pertusa on the turf algae. The turf-forming red algae lowered the abundance of U. pertusa presumably by inhibiting the recruitment of U. pertusa; this effect was consistent along the tidal height. However, the greater abundance of Enteromorpha was observed in the presence of turf in the upper zone, indicating a positive effect of turf on Enteromorpha. Once U. pertusa was successfully recruited and grown to the adult plant, it inhibited the growth of turf by shading, which was effective both in winter and summer regardless of desiccation stress. No scouring and allelopathic effects of U. pertusa on the turf were detected. When an open substrate was provided, Enteromorpha colonized the space faster than any other species in the upper zone, but the turf was the fastest one followed by U. pertusa and Enteromorpha in the lower zone. Results indicated that patterns of interaction represented a complex network with no ultimate winner and the outcomes of interaction varied over time and space. [source] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||