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Diversity
Kinds of Diversity Terms modified by Diversity Selected AbstractsCULTURAL DIVERSITY, DISCRIMINATION, AND ECONOMIC OUTCOMES: AN EXPERIMENTAL ANALYSISECONOMIC INQUIRY, Issue 2 2007PAUL J. FERRARO Does cultural diversity affect economic outcomes? We develop an experimental framework that complements ongoing research on this question. We vary the ethnic mix of bargaining sessions to study intercultural interactions among members of U.S. Hispanic and Navajo cultures. We control for demographic differences in our subject pools and elicit beliefs directly in order to differentiate between statistical discrimination and preference-based discrimination. Hispanic and Navajo subjects behave differently, and their behavior is affected by the ethnic composition of the experimental session. Our experimental framework can shed light on economic behavior and outcomes in societies of mixed ethnicity, race, and religion. (JEL C78, C90, Z10) [source] COEVOLUTION DRIVES TEMPORAL CHANGES IN FITNESS AND DIVERSITY ACROSS ENVIRONMENTS IN A BACTERIA,BACTERIOPHAGE INTERACTIONEVOLUTION, Issue 8 2008Samantha E. Forde Coevolutionary interactions are thought to play a crucial role in diversification of hosts and parasitoids. Furthermore, resource availability has been shown to be a fundamental driver of species diversity. Yet, we still do not have a clear understanding of how resource availability mediates the diversity generated by coevolution between hosts and parasitoids over time. We used experiments with bacteria and bacteriophage to test how resources affect variation in the competitive ability of resistant hosts and temporal patterns of diversity in the host and parasitoid as a result of antagonistic coevolution. Bacteria and bacteriophage coevolved for over 150 bacterial generations under high and low-resource conditions. We measured relative competitive ability of the resistant hosts and phenotypic diversity of hosts and parasitoids after the initial invasion of resistant mutants and again at the end of the experiment. Variation in relative competitive ability of the hosts was both time- and environment-dependent. The diversity of resistant hosts, and the abundance of host-range mutants attacking these phenotypes, differed among environments and changed over time, but the direction of these changes differed between the host and parasitoid. Our results demonstrate that patterns of fitness and diversity resulting from coevolutionary interactions can be highly dynamic. [source] HOW BRIGHT AND HOW NASTY: EXPLAINING DIVERSITY IN WARNING SIGNAL STRENGTHEVOLUTION, Issue 3 2007Michael P. Speed The conspicuous displays that warn predators of defenses carried by potential prey have been of interest to evolutionary biologists from the time of Wallace and Darwin to the present day. Although most studies implicitly assume that these "aposematic" warning signals simply indicate the presence of some repellent defense such as a toxin, it has been speculated that the intensity of the signal might reliably indicate the strength of defense so that, for example, the nastiest prey might "shout loudest" about their unprofitability. Recent phylogenetic and empirical studies of Dendrobatid frogs provide contradictory views, in one instance showing a positive correlation between toxin levels and conspicuousness, in another showing a breakdown of this relationship. In this paper we present an optimization model, which can potentially account for these divergent results. Our model locates the optimal values of defensive traits that are influenced by a range of costs and benefits. We show that optimal aposematic conspicuousness can be positively correlated with optimal prey toxicity, especially where population sizes and season lengths vary between species. In other cases, optimal aposematic conspicuousness may be negatively correlated with toxicity; this is especially the case when the marginal costs of aposematic displays vary between members of different populations. Finally, when displays incur no allocation costs there may be no single optimum value for aposematic conspicuousness, rather a large array of alternative forms of a display may have equal fitness. [source] DIVERSITY IN THE WEAPONS OF SEXUAL SELECTION: HORN EVOLUTION IN THE BEETLE GENUS ONTHOPHAGUS (COLEOPTERA: SCARABAEIDAE)EVOLUTION, Issue 5 2005Douglas J. Emlen Abstract Both ornaments and weapons of sexual selection frequently exhibit prolific interspecific diversity of form. Yet, most studies of this diversity have focused on ornaments involved with female mate choice, rather than on the weapons of male competition. With few exceptions, the mechanisms of divergence in weapon morphology remain largely unexplored. Here, we characterize the evolutionary radiation of one type of weapon: beetle horns. We use partial sequences from four nuclear and three mitochondrial genes to develop a phylogenetic hypothesis for a worldwide sample of 48 species from the dung beetle genus Onthophagus (Coleoptera: Scarabaeidae). We then use these data to test for multiple evolutionary origins of horns and to characterize the evolutionary radiation of horns. Although our limited sampling of one of the world's most species-rich genera almost certainly underestimates the number of evolutionary events, our phylogeny reveals prolific evolutionary lability of these exaggerated sexually selected weapons (more than 25 separate gains and losses of five different horn types). We discuss these results in the context of the natural history of these beetles and explore ways that sexual selection and ecology may have interacted to generate this extraordinary diversity of weapon morphology. [source] A METAPOPULATION PERSPECTIVE ON GENETIC DIVERSITY AND DIFFERENTIATION IN PARTIALLY SELF-FERTILIZING PLANTSEVOLUTION, Issue 12 2002Pärk. Ingvarsson Abstract., Partial self-fertilization is common in higher plants. Mating system variation is known to have important consequences for how genetic variation is distributed within and among populations. Selfing is known to reduce effective population size, and inbreeding species are therefore expected to have lower levels of genetic variation than comparable out crossing taxa. However, several recent empirical studies have shown that reductions in genetic diversity within populations of inbreeding species are far greater than the expected reductions based on the reduced effective population size. Two different processes have been argued to cause these patterns, selective sweeps (or hitchhiking) and background selection. Both are expected to be most effective in reducing genetic variation in regions of low recombination rates. Selfing is known to reduce the effective recombination rate, and inbreeding taxa are thus thought to be particularly vulnerable to the effects of hitchhiking or background selection. Here I propose a third explanation for the lower-than-expected levels of genetic diversity within populations of selfing species; recurrent extinctions and recolonizations of local populations, also known as metapopulation dynamics. I show that selfing in a metapopulation setting can result in large reductions in genetic diversity within populations, far greater than expected based the lower effective population size inbreeding species is expected to have. The reason for this depends on an interaction between selfing and pollen migration. [source] PHYLOGENETIC RELATIONSHIPS AND MORPHOLOGICAL DIVERSITY IN DARWIN'S FINCHES AND THEIR RELATIVESEVOLUTION, Issue 6 2002Kevin J. Burns Abstract Despite the importance of Darwin's finches to the development of evolutionary theory, the origin of the group has only recently been examined using a rigorous, phylogenetic methodology that includes many potential outgroups. Knowing the evolutionary relationships of Darwin's finches to other birds is important for understanding the context from which this adaptive radiation arose. Here we show that analysis of mitochondrial DNA sequence data from the cytochrome b gene confirm that Darwin's finches are monophyletic. In addition, many taxa previously proposed as the sister taxon to Darwin's finches can be excluded as their closest living relative. Darwin's finches are part of a well-supported monophyletic group of species, all of which build a domed nest. All but two of the non-Darwin's finches included in this clade occur on Caribbean islands and most are Caribbean endemics. These close relatives of Darwin's finches show a diversity of bill types and feeding behaviors similar to that observed among Darwin's finches themselves. Recent studies have shown that adaptive evolution in Darwin's finches occurred relatively quickly. Our data show that among the relatives of Darwin's finches, the evolution of bill diversity was also rapid and extensive. [source] DOES DIVERSITY IN URBAN SPACE ENHANCE INTERGROUP CONTACT AND TOLERANCE?GEOGRAFISKA ANNALER SERIES B: HUMAN GEOGRAPHY, Issue 1 2009Terje Wessel ABSTRACT. Contemporary urban theory has started to question the elevation of diversity as a panacea for enduring urban problems , segregation, prejudice and intergroup hostility. This critique coincides with an opposite tendency within classic contact theory and research. The latter tradition has developed an increasing enthusiasm for face-to-face interaction. The contact hypothesis, which presupposes established contact, has received conclusive support independent of target groups and contact settings. Research on ,lived diversity', which includes both contact and lack of contact, offers two supplementary insights. It shows, on the one hand, that boundaries are inscribed in social spaces. Physical proximity between ethnic and social groups tends to have a minor effect on interaction. Interaction, on the other hand, is not essential to attitude formation. Both subfields within contact research have confirmed that urban space may act as a catalyst for tolerant attitudes. This observation corresponds with increasing recognition of affective states, such as empathy, anxiety and group threat. Contact research has therefore, in summary, transcended the scope of the contact hypothesis. It has expanded into the realm of urban theory, which foreshadows future collaboration between the two traditions. Some key points for such exchange are suggested at the end of the article. Future research should combine an open-ended approach to casual contact with a diversified conception of diversity and a richer conception of urban space. A move in this direction would leave substantial space for geographical research. [source] DIVERSITY AND EQUITY ISSUESHIGHER EDUCATION ABSTRACTS, Issue 2 2004Article first published online: 30 OCT 200 First page of article [source] CORAL REEF FISHES/DYNAMICS AND DIVERSITY IN A COMPLEX ECOSYSTEM.JOURNAL OF FISH BIOLOGY, Issue 3 2004Edited by P. F. Sale. xiv 549 pp. No abstract is available for this article. [source] TEXTUAL REPRESENTATION OF DIVERSITY IN COAMFTE ACCREDITED DOCTORAL PROGRAMSJOURNAL OF MARITAL AND FAMILY THERAPY, Issue 1 2006John J. Lawless The use of the Internet is growing at a staggering pace. One significant use of the Internet is for potential students and the parents of potential students to explore educational possibilities. Along these lines potential marriage and family therapy students may have many questions that include a program's commitment to cultural diversity. This study utilized qualitative content analysis methodology in combination with critical race theory to examine how Commission On Accreditation for Marriage and Family Therapy Education (COAMFTE) accredited doctoral programs represented cultural text on their World Wide Web pages. Findings indicate that many COAMFTE-accredited doctoral programs re-present programmatic information about diversity that appear to be incongruent with cultural sensitivity. These apparent incongruities are highlighted by the codification, inconsistent, and isolated use of cultural text. In addition, cultural text related to social justice was absent. Implications and suggestions are discussed. [source] DIVERSITY AND THE JOURNALJOURNAL OF MARITAL AND FAMILY THERAPY, Issue 4 2004Karen S. Wampler No abstract is available for this article. [source] PHYLOGENETIC ANALYSIS OF PSEUDOCHLORODESMIS STRAINS REVEALS CRYPTIC DIVERSITY ABOVE THE FAMILY LEVEL IN THE SIPHONOUS GREEN ALGAE (BRYOPSIDALES, CHLOROPHYTA),JOURNAL OF PHYCOLOGY, Issue 3 2009Heroen Verbruggen The genus Pseudochlorodesmis (Bryopsidales) is composed of diminutive siphons of extreme morphological simplicity. The discovery of Pseudochlorodesmis -like juveniles in more complex Bryopsidales (e.g., the Halimeda microthallus stage) jeopardized the recognition of this genus. Confronted with this uncertainty, taxonomists transferred many simple siphons into a new genus, Siphonogramen. In this study, we used a multimarker approach to clarify the phylogenetic and taxonomic affinities of the Pseudochlorodesmis-Siphonogramen (PS) complex within the more morphologically complex bryopsidalean taxa. Our analyses reveal a new layer of diversity largely distinct from the lineages containing the structurally complex genera. The PS complex shows profound cryptic diversity exceeding the family level. We discuss a potential link between thallus complexity and the prevalence and profundity of cryptic diversity. For taxonomic simplicity and as a first step toward clarifying the taxonomy of these simple siphons, we propose to maintain Pseudochlorodesmis as a form genus and subsume Siphonogramen and Botryodesmis therein. [source] GENETIC DIVERSITY AND INTROGRESSION IN TWO CULTIVATED SPECIES (PORPHYRA YEZOENSIS AND PORPHYRA TENERA) AND CLOSELY RELATED WILD SPECIES OF PORPHYRA (BANGIALES, RHODOPHYTA),JOURNAL OF PHYCOLOGY, Issue 2 2009Kyosuke Niwa We investigated the genetic variations of the samples that were tentatively identified as two cultivated Porphyra species (Porphyra yezoensis Ueda and Porphyra tenera Kjellm.) from various natural populations in Japan using molecular analyses of plastid and nuclear DNA. From PCR-RFLP analyses using nuclear internal transcribed spacer (ITS) rDNA and plastid RUBISCO spacer regions and phylogenetic analyses using plastid rbcL and nuclear ITS-1 rDNA sequences, our samples from natural populations of P. yezoensis and P. tenera showed remarkably higher genetic variations than found in strains that are currently used for cultivation. In addition, it is inferred that our samples contain four wild Porphyra species, and that three of the four species, containing Porphyra kinositae, are closely related to cultivated Porphyra species. Furthermore, our PCR-RFLP and molecular phylogenetic analyses using both the nuclear and plastid DNA demonstrated the occurrence of plastid introgression from P. yezoensis to P. tenera and suggested the possibility of plastid introgression from cultivated P. yezoensis to wild P. yezoensis. These results imply the importance of collecting and establishing more strains of cultivated Porphyra species and related wild species from natural populations as genetic resources for further improvement of cultivated Porphyra strains. [source] CYANIDIA (CYANIDIALES) POPULATION DIVERSITY AND DYNAMICS IN AN ACID-SULFATE-CHLORIDE SPRING IN YELLOWSTONE NATIONAL PARK,JOURNAL OF PHYCOLOGY, Issue 1 2007Corinne R. Lehr The unicellular eukaryotic algae Cyanidium, Galdieria, and Cyanidioschyzon (herein referred to as "cyanidia") are the only photoautotrophs occurring in acidic (pH<4.0) geothermal environments at temperatures above 40°C. In Yellowstone National Park (YNP), we examined an annual event we refer to as "mat decline," where cyanidial mats undergo a seasonably defined color fading. Monthly sampling of chemical, physical, and biological features revealed that spring aqueous chemistry was essentially invariant over the 1-year sampling period. However, multiple regression analysis suggested that a significant proportion of algal most probable number (MPN) count variation could be explained by water temperature and UV,visible (VIS) light exposure. Irradiance manipulations (filtering) were then coupled with 14CO2 incorporation experiments to directly demonstrate UV inhibition of photosynthesis. Population dynamics were also evident in 18S rDNA PCR clone libraries, which were different in composition at MPN maxima and minima, and again evident in PCR-amplified chloroplast genomic short sequence repeat (SSR) analysis. PCR-cloned SSRs of the YNP isolates and mats were very similar to Cyanidioschyzon merolae Luca, Taddei et Varano, although distance analysis could distinguish the YNP cyanidia from the genome sequenced C. merolae that was isolated in Italy. Unexpectedly, while phylogenetic analysis of 18S rDNA sequences and SSR sequences derived from YNP cyanidial mats and pure cultures suggested these algae are most closely related to C. merolae (99.7% identity), cell morphology was consistent with the genera Galdieria and Cyanidium. [source] GENE SEQUENCE DIVERSITY AND THE PHYLOGENETIC POSITION OF ALGAE ASSIGNED TO THE GENERA PHAEOPHILA AND OCHLOCHAETE (ULVOPHYCEAE, CHLOROPHYTA),JOURNAL OF PHYCOLOGY, Issue 4 2004Charles J. O'Kelly The phylogenetic position of microfilamentous marine green algae assigned to the species Phaeophila dendroides, Entocladia tenuis (Phaeophila tenuis, and Ochlochaete hystrix was examined through phylogenetic analyses of nuclear-encoded small subunit rDNA and chloroplast-encoded tufA gene sequences. These analyses placed the P. dendroides strains within the Ulvophyceae, at the base of a clade that contains representatives of the families Ulvaceae, Ulvellaceae, and the species Bolbocoleon piliferum, supporting an earlier hypothesis that P. dendroides constitutes a distinct lineage. Substantial divergence in both nuclear and plastid DNA sequences exists among strains of P. dendroides from different geographic localities, but these isolated strains are morphologically indistinguishable. The lineage may have an accelerated rate of gene sequence evolution relative to other microfilamentous marine green algae. Entocladia tenuis and O. hystrix are placed neither in the P. dendroides clade nor in the Ulvellaceae as previous taxonomic schemes predicted but instead form a new clade or clades at the base of the Ulvaceae. Ruthnielsenia gen. nov. is proposed to accommodate Kylin's species, which cannot be placed in Entocladia (=Acrochaete), Phaeophila, or Ochlochaete. Ruthnielsenia tenuis (Kylin) comb. nov., previously known only from Atlantic coasts, is reported for the first time from the Pacific coast of North America (San Juan Island, WA, USA). Isolates of R. tenuis from the Atlantic and Pacific coasts of North America have identical small subunit rDNA and tufA gene sequences. [source] SEAWEED ABUNDANCE AND DIVERSITY IN HIGH ENERGY AND LOW ENERGY AREAS AT PORT ARANSAS, TEXAS JETTIESJOURNAL OF PHYCOLOGY, Issue 3 2001Article first published online: 24 SEP 200 Agan, J. C. & Lehman, R. L. Department of Physical and Life Sciences, Texas A&M University-Corpus Christi 6300 Ocean Dr., Corpus Christi, TX 78412 USA Benthic algal sampling from high and low energy zones at a selected site on the south jetty at Port Aransas, Texas was completed between April 1999 and February 2000. Species composition and seasonal periodicity in relation to temperature and salinity fluctuations were determined. Dominant plants throughout the year included Bryocladia cuspidata, Bryocladia thyrsigera, Gelidium pusillum, Centroceras clavulatum, Ulva fasciata, and Padina gymnospora. The Rhodophyta dominated species coverage, along with biomass accumulation, although Chlorophyta species accrued the greatest biomass on the high energy side in April and June sampling. Chlorophyta are important to benthic coverage and biomass in the shallowest of waters, despite being fewer in species richness. Phaeophyta species including Petalonia fascia, Hincksia mitchelliae, and Ectocarpus siliculosus were found only during the cooler months. Padina gymnospora was the one exception as it was collected year-round. Results indicate that a greater Rhodophyta abundance was found on the channel side (low energy), where as, the surf side (high energy) contained a greater Chlorophyta abundance. Phaeophyta abundance for both high and low energy sites were comparable possibly due to the greater depth of water in which they are located. Little variance occurred in average biomass accumulation throughout the year. Highest biomass was in August (216.613g dry weight) with lowest occurring in April (107.4205g dry weight). [source] SEAWEED ABUNDANCE AND DIVERSITY IN HIGH ENERGY AND LOW ENERGY AREAS AT PORT ARANSAS, TEXAS JETTIESJOURNAL OF PHYCOLOGY, Issue 2001Article first published online: 9 OCT 200 Agan, J. C. & Lehman, R. L. Department of Physical and Life Sciences, Texas A&M University-Corpus Christi 6300 Ocean Dr., Corpus Christi, TX 78412 USA Benthic algal sampling from high and low energy zones at a selected site on the south jetty at Port Aransas, Texas was completed between April 1999 and February 2000. Species composition and seasonal periodicity in relation to temperature and salinity fluctuations were determined. Dominant plants throughout the year included Bryocladia cuspidata, Bryocladia thyrsigera, Gelidium pusillum, Centroceras clavulatum, Ulva fasciata, and Padina gymnospora. The Rhodophyta dominated species coverage, along with biomass accumulation, although Chlorophyta species accrued the greatest biomass on the high energy side in April and June sampling. Chlorophyta are important to benthic coverage and biomass in the shallowest of waters, despite being fewer in species richness. Phaeophyta species including Petalonia fascia, Hincksia mitchelliae, and Ectocarpus siliculosus were found only during the cooler months. Padina gymnospora was the one exception as it was collected year-round. Results indicate that a greater Rhodophyta abundance was found on the channel side (low energy), where as, the surf side (high energy) contained a greater Chlorophyta abundance. Phaeophyta abundance for both high and low energy sites were comparable possibly due to the greater depth of water in which they are located. Little variance occurred in average biomass accumulation throughout the year. Highest biomass was in August (216.613g dry weight) with lowest occurring in April (107.4205g dry weight). [source] CONFUSING CONVERGENT MORPHOLOGIES: DIVERSITY AND DIFFICULTIES IN NEW ZEALAND ERYTHROPELTIDALES AND BANGIALESJOURNAL OF PHYCOLOGY, Issue 2000W.A. Nelson An examination of New Zealand species of Porphyra and Bangia has led to the discovery of unexpectedly high diversity. In excess of 30 species of Porphyra and 5 species of Bangia can be distinguished, based on 18S rDNA sequence data. It is possible to develop a workable taxonomic framework to distinguish species of Porphyra found within this geographic region using a range of characters (morphological, anatomical, biochemical, physiological, life history characteristics). However, the taxonomic distinctions do not necessarily reflect phylogenetic relationships revealed by sequence analyses: convergence in character states is obscuring relationships. In the course of our work we have discovered that four species, originally described on the basis of traditional morphological and anatomical characters as Porphyra or Bangia, are more closely related to members of the order Erythropeltidales than to the Bangiales. These results are challenging us to consider new ways of describing and defining these organisms. We are finding convergence in character states, not only within Porphyra sens. lat. But spanning both the Bangiales and Erythropeltidales, which confounds both taxonomic distinctions and also phylogenetic hypotheses based on morphology and anatomy. This confusion could be countered effectively by the inclusion of molecular sequence data based on vouchered or type material in descriptions of taxa in the orders Bangiales and Erythropeltidales. This would allow conclusive identification of collected material by appropriate molecular tests, which are quicker and more direct identification tools than, for example, using characters drawn from the growth of these organisms under controlled culture conditions. [source] THE MINOAN FALLACY: CULTURAL DIVERSITY AND MORTUARY BEHAVIOUR ON CRETE AT THE BEGINNING OF THE BRONZE AGEOXFORD JOURNAL OF ARCHAEOLOGY, Issue 1 2009BORJA LEGARRA HERRERO Summary We are becoming increasingly aware of regional data patterning in the archaeological record of Prepalatial Crete, yet a theoretically informed and methodologically systematic study assessing the significance of such differences is still lacking. This article investigates variation through the rich mortuary record of the period and explores the significance of such diversity for our understanding of Prepalatial Crete. A detailed analysis using mortuary data reveals a complex spatial and temporal variation in the record which raises questions about social, political and ideological differences between communities on the island during the early periods of the Early Bronze Age. Prepalatial Crete emerges from this analysis as a complex context resulting from an intricate combination of local and regional histories and trajectories and far from the unified culture that the term ,Minoan' implies. [source] DEAD MEN TELL NO TALES: ETHNIC DIVERSITY IN SICILIAN COLONIES AND THE EVIDENCE OF THE CEMETERIESOXFORD JOURNAL OF ARCHAEOLOGY, Issue 2 2005GILLIAN SHEPHERD Summary. There have been recent suggestions that an indigenous element in ancient Greek settlements in Sicily can be detected through funerary customs. This paper reviews the evidence for ,indigenous' burial methods in Greek cemeteries, concentrating on multiple, contracted and acephalous burials. It argues that such evidence is limited and open to various interpretations and that while it is highly likely that Greek settlements did incorporate an indigenous population, the funerary record cannot be used as a reliable identifier of such groups. The paper also briefly assesses the evidence for the presence of Greeks deriving from areas other than the historical mother-cities and suggests that such individuals are also very difficult to detect. It concludes that the general impression given by Sicilian Greek cemeteries is one of overall subscription to coherent burial systems, which may be viewed as part of an attempt to forge a unified and independent cultural identity. [source] UNDERSTANDING DIVERSITY IN AFRICAN AMERICAN POLITICAL THOUGHT: COMPARING DU BOIS, WASHINGTON, GARVEY AND ELIJAH MUHAMMADPOLITICS & POLICY, Issue 2 2000Jaswant M. Sullivan This study provides a systematic and comparative treatment of four African-American political thinkers. Previous works on African-American political thought have been mostly biographical and idiographic treatments. This study uses the comparative method to systematically evaluate the political philosophies of W. E. B. Du Bois, Booker T. Washington, Elijah Muhammad, and Marcus Garvey. Although the study does not claim that the thinker's political thought is causally related to his activist position, it is expected that there is a logical connection between them. The study introduces a framework which combines two dimensions into four categories. The four thinkers are hypothesized to each fit a different category. The findings support the hypothesized categorization. [source] AGAINST THE CELEBRATION OF DIVERSITYBRITISH JOURNAL OF PSYCHOTHERAPY, Issue 1 2008Farhad Dalal abstract The paper enquires into the pertinence of the ,diversity' agenda for psychotherapy and psychoanalysis. It critically tracks how multiculturalism, anti-racism and ,diversity' emerge from the philosophy of liberalism. Some of the contradictions and difficulties in each of these discourses are highlighted. The paper then argues that the various schools of psychotherapy and psychoanalysis tend to be intolerant of each other's world-views and forms of practice. And finally, the paper takes up how three different strands within the profession might view, and so respond to the theme of diversity in the clinic. [source] TASTE FOR VARIETY AND OPTIMUM PRODUCT DIVERSITY IN AN OPEN ECONOMYBULLETIN OF ECONOMIC RESEARCH, Issue 2 2009Javier Coto-Martínez D43; F12 ABSTRACT We extend the Benassy,taste for variety' model to an open economy setting. With the Benassy effect, the market equilibrium is inefficient, openness reduces the varieties provided in the unconstrained optimum and there are potential gains from international coordination. [source] FUNCTIONAL DIVERSITY OF MAMMALIAN TYPE 2C PROTEIN PHOSPHATASE ISOFORMS: NEW TALES FROM AN OLD FAMILYCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 2 2008Gang Lu SUMMARY 1The Type 2C protein phosphatases (PP2C) represent a highly conserved gene family in the mammalian genome. Recent studies have revealed that PP2C isoforms possess unique patterns of tissue and subcellular distribution associated with diverse functionalities. 2The functional importance of PP2C isoforms has been shown in a plethora of signalling networks controlling cell differentiation, proliferation, growth, survival and metabolism. However, little is known about the regulatory mechanisms of PP2C at the molecular level. It is uncertain how PP2C isoforms are recruited, activated and inactivated during signalling transduction processes. 3In the present paper, an overview of the critical functions of individual PP2C isoforms in regulating cellular signalling events will be provided, along with our perspectives on the challenging issues to be addressed. It is clear that a better understanding of the complex biological effects elicited by specific signalling pathways involving PP2C isoforms has great potential for developing novel therapies for a variety of human diseases, including cancer, diabetes and neural disorders, as well as cardiovascular diseases. [source] The Craniofacial Reconstruction from the Local Structural Diversity of SkullsCOMPUTER GRAPHICS FORUM, Issue 7 2008Yuru Pei Abstract The craniofacial reconstruction is employed as an initialization of the identification from skulls in forensics. In this paper, we present a two-level craniofacial reconstruction framework based on the local structural diversity of the skulls. On the low level, the holistic reconstruction is formulated as the superimposition of the selected tissue map on the novel skull. The crux is the accurate map registration, which is implemented as a warping guided by the 2D feature curve patterns. The curve pattern extraction under an energy minimization framework is proposed for the automatic feature labeling on the skull depth map. The feature configuration on the warped tissue map is expected to resemble that on the novel skull. In order to make the reconstructed faces personalized, on the high level, the local facial features are estimated from the skull measurements via a RBF model. The RBF model is learnt from a dataset of the skull and the face feature pairs extracted from the head volume data. The experiments demonstrate the facial outlooks can be reconstructed feasibly and efficiently. [source] A Call to Action for Conserving Biological Diversity in the Face of Climate ChangeCONSERVATION BIOLOGY, Issue 5 2010Malcolm Hunter Jr. No abstract is available for this article. [source] Phylogenetic Comparative Methods Strengthen Evidence for Reduced Genetic Diversity among Endangered TetrapodsCONSERVATION BIOLOGY, Issue 5 2010PATRICK A. FLIGHT evolución de la historia de vida; extinción; heterocigosidad de proteínas; regresión filogenética; tamaño poblacional efectivo Abstract:,The fitness of species with little genetic diversity is expected to be affected by inbreeding and an inability to respond to environmental change. Conservation theory suggests that endangered species will generally demonstrate lower genetic diversity than taxa that are not threatened. This hypothesis has been challenged because the time frame of anthropogenic extinction may be too fast to expect genetic factors to significantly contribute. I conducted a meta-analysis to examine how genetic diversity in 894 tetrapods correlates with extinction threat level. Because species are not evolutionarily independent, I used a phylogenetic regression framework to address this issue. Mean genetic diversity of tetrapods, as assessed by protein heterozygosity, was 29.7,31.5% lower on average in threatened species than in their nonthreatened relatives, a highly significant reduction. Within amphibians as diversity decreased extinction risk increased in phylogenetic models, but not in nonphylogenetic regressions. The effects of threatened status on diversity also remained significant after accounting for body size in mammals. These results support the hypothesis that genetic effects on population fitness are important in the extinction process. Resumen:,Se espera que la adaptabilidad de una especie con poca diversidad genética sea afectada por la endogamia y una incapacidad para responder a cambios ambientales. La teoría de la conservación sugiere que las especies en peligro generalmente muestran menor diversidad genética que taxa que no están amenazados. Esta hipótesis ha sido cuestionada porque el período de tiempo de la extinción antropogénica puede ser muy rápido para esperar que los factores genéticos contribuyan significativamente. Realice un meta-análisis para examinar cómo se correlaciona la diversidad genética de 894 tetrápodos con el nivel de amenaza de extinción. Debido a que las especies no son independientes evolutivamente, utilice un marco de regresión filogenética para abordar este tema. La media de la diversidad genética de tetrápodos, medida como la heterocigosidad de proteínas, fue 29.7,31.5% menor en las especies amenazadas que en sus parientes no amenazados, una reducción altamente significativa. En anfibios, a medida que disminuía la diversidad el riesgo de extinción incrementaba en los modelos filogenéticos, pero no en las regresiones no filogenéticas. El efecto del estatus de amenaza sobre la biodiversidad también permaneció significativo después de considerar el tamaño corporal de mamíferos. Estos resultados dan soporte a la hipótesis de que los efectos genéticos sobre la adaptabilidad de la población son importantes en el proceso de extinción. [source] Expanding the Global Network of Protected Areas to Save the Imperiled Mediterranean BiomeCONSERVATION BIOLOGY, Issue 1 2009EMMA C. UNDERWOOD análisis de disparidad; áreas protegidas; biodiversidad; ecosistemas Mediterráneos; pérdida de hábitat Abstract:,Global goals established by the Convention on Biological Diversity stipulate that 10% of the world's ecological regions must be effectively conserved by 2010. To meet that goal for the mediterranean biome, at least 5% more land must be formally protected over the next few years. Although global assessments identify the mediterranean biome as a priority, without biologically meaningful analysis units, finer-resolution data, and corresponding prioritization analysis, future conservation investments could lead to more area being protected without increasing the representation of unique mediterranean ecosystems. We used standardized analysis units and six potential natural vegetation types stratified by 3 elevation zones in a global gap analysis that systematically explored conservation priorities across the mediterranean biome. The highest levels of protection were in Australia, South Africa, and California-Baja California (from 9,11%), and the lowest levels of protection were in Chile and the mediterranean Basin (<1%). Protection was skewed to montane elevations in three out of five regions. Across the biome only one of the six vegetation types,mediterranean shrubland,exceeded 10% protection. The remaining vegetation types,grassland, scrub, succulent dominated, woodland, and forest,each had <3% protection. To guard against biases in future protection efforts and ensure the protection of species characteristic of the mediterranean biome, we identified biodiversity assemblages with <10% protection and subject to >30% conversion and suggest that these assemblages be elevated to high-priority status in future conservation efforts. Resumen:,Las metas globales establecidas por la Convención sobre Diversidad Biológica estipulan que 10% de las regiones ecológicas del mundo deberán estar conservadas efectivamente en 2010. Para alcanzar esa meta en el bioma mediterráneo, por lo menos 5% más de superficie debe estar protegida formalmente en los próximos años. Aunque las evaluaciones globales identifican al bioma mediterráneo como una prioridad, sin unidades de análisis biológicamente significativas, datos de resolución más fina y los correspondientes análisis de priorización, las inversiones futuras en conservación pudieran conducir a la protección de más superficie sin incrementar la representación de los ecosistemas mediterráneos únicos. Utilizamos unidades de análisis estandarizadas y seis tipos potenciales de vegetación natural estratificados en tres zonas de elevación en un análisis global de disparidad que exploró sistemáticamente las prioridades de conservación en el bioma mediterráneo. Los niveles de protección más altos se localizaron en Australia, África del Sur y California-Baja California (de 9,11%) y los niveles de protección más bajos se localizaron en Chile y la Cuenca del mediterráneo (<1%). La protección estaba sesgada hacia elevaciones altas en tres de las cinco regiones. En todo el bioma, solo uno de los seis tipos de vegetación,matorral mediterráneo,excedió 10% de protección. Los tipos de vegetación restantes,pastizal, matorral, dominio de suculentas, y bosques,tenían <3% de protección cada uno. Para evitar sesgos en futuros esfuerzos de protección y asegurar la protección de especies características del bioma mediterráneo, identificamos ensambles de biodiversidad con <10% de protección y sujetos a >30% de conversión y sugerimos que estos ensambles sean elevados a un estatus de alta prioridad en esfuerzos de conservación en el futuro. [source] Quantification of Extinction Risk: IUCN's System for Classifying Threatened SpeciesCONSERVATION BIOLOGY, Issue 6 2008GEORGINA M. MACE definición de prioridades de conservación; especies amenazadas; Lista Roja UICN; riesgo de extinción Abstract:,The International Union for Conservation of Nature (IUCN) Red List of Threatened Species was increasingly used during the 1980s to assess the conservation status of species for policy and planning purposes. This use stimulated the development of a new set of quantitative criteria for listing species in the categories of threat: critically endangered, endangered, and vulnerable. These criteria, which were intended to be applicable to all species except microorganisms, were part of a broader system for classifying threatened species and were fully implemented by IUCN in 2000. The system and the criteria have been widely used by conservation practitioners and scientists and now underpin one indicator being used to assess the Convention on Biological Diversity 2010 biodiversity target. We describe the process and the technical background to the IUCN Red List system. The criteria refer to fundamental biological processes underlying population decline and extinction. But given major differences between species, the threatening processes affecting them, and the paucity of knowledge relating to most species, the IUCN system had to be both broad and flexible to be applicable to the majority of described species. The system was designed to measure the symptoms of extinction risk, and uses 5 independent criteria relating to aspects of population loss and decline of range size. A species is assigned to a threat category if it meets the quantitative threshold for at least one criterion. The criteria and the accompanying rules and guidelines used by IUCN are intended to increase the consistency, transparency, and validity of its categorization system, but it necessitates some compromises that affect the applicability of the system and the species lists that result. In particular, choices were made over the assessment of uncertainty, poorly known species, depleted species, population decline, restricted ranges, and rarity; all of these affect the way red lists should be viewed and used. Processes related to priority setting and the development of national red lists need to take account of some assumptions in the formulation of the criteria. Resumen:,La Lista Roja de Especies Amenazadas de la UICN (Unión Internacional para la Conservación de la Naturaleza) fue muy utilizada durante la década de l980 para evaluar el estatus de conservación de especies para fines políticos y de planificación. Este uso estimuló el desarrollo de un conjunto nuevo de criterios cuantitativos para enlistar especies en las categorías de amenaza: en peligro crítico, en peligro y vulnerable. Estos criterios, que se pretendía fueran aplicables a todas las especies excepto microorganismos, eran parte de un sistema general para clasificar especies amenazadas y fueron implementadas completamente por la UICN en 2000. El sistema y los criterios han sido ampliamente utilizados por practicantes y científicos de la conservación y actualmente apuntalan un indicador utilizado para evaluar el objetivo al 2010 de la Convención de Diversidad Biológica. Describimos el proceso y el respaldo técnico del sistema de la Lista Roja de la IUCN. Los criterios se refieren a los procesos biológicos fundamentales que subyacen en la declinación y extinción de una población. Pero, debido a diferencias mayores entre especies, los procesos de amenaza que los afectan y la escasez de conocimiento sobre la mayoría de las especies, el sistema de la UICN tenía que ser amplio y flexible para ser aplicable a la mayoría de las especies descritas. El sistema fue diseñado para medir los síntomas del riesgo de extinción, y utiliza cinco criterios independientes que relacionan aspectos de la pérdida poblacional y la declinación del rango de distribución. Una especie es asignada a una categoría de amenaza si cumple el umbral cuantitativo por lo menos para un criterio. Los criterios, las reglas acompañantes y las directrices utilizadas por la UICN tienen la intención de incrementar la consistencia, transparencia y validez de su sistema de clasificación, pero requiere algunos compromisos que afectan la aplicabilidad del sistema y las listas de especies que resultan. En particular, se hicieron selecciones por encima de la evaluación de incertidumbre, especies poco conocidas, especies disminuidas, declinación poblacional, rangos restringidos y rareza; todas estas afectan la forma en que las listas rojas deberían ser vistas y usadas. Los procesos relacionados con la definición de prioridades y el desarrollo de las listas rojas nacionales necesitan considerar algunos de los supuestos en la formulación de los criterios. [source] Effects of Conversion of Dry Tropical Forest to Agricultural Mosaic on Herpetofaunal AssemblagesCONSERVATION BIOLOGY, Issue 2 2008IRERI SUAZO-ORTUÑO atributos de vulnerabilidad; bosque tropical seco; ensambles herpetofaunísticos; modificación del hábitat; mosaico agrícola Abstract:,We explored the impact of forest conversion to agricultural mosaic on anuran, lizard, snake, and turtle assemblages of Neotropical dry forests. Over 2 years, we sampled 6 small watersheds on the west coast of Mexico, 3 conserved and 3 disturbed. The disturbed watersheds were characterized by a mosaic of pastures and cultivated fields (corn, beans, squash) intermingled with patches of different successional stages of dry forest. In each watershed, we conducted 11 diurnal and nocturnal time-constrained searches in 10 randomly established plots. We considered vulnerability traits of species in relation to habitat modification. Eighteen anuran, 18 lizard, 23 snake, and 3 turtle species were recorded. Thirty-six species (58%) occurred in both forest conditions, and 14 (22%) and 12 species (19%) occurred only in the conserved and disturbed sites, respectively. Assemblages responded differently to disturbance. Species richness, diversity, and abundance of lizards were higher in disturbed forests. Anuran diversity and species richness were lower in disturbed forest but abundance was similar in both forest conditions. Diversity, richness, and abundance of turtles were lower in disturbed forest. The structure and composition of snake assemblages did not differ between forest conditions. We considered species disturbance sensitive if their abundance was significantly less in disturbed areas. Four anuran (22%), 2 lizard (11%), and 3 turtle (100%) species were sensitive to disturbance. No snake species was sensitive. The decline in abundance of disturbance-sensitive species was associated with the reduction of forest canopy cover, woody stem cover, roots, and litter-layer ground cover. Anuran species with small body size and direct embryonic development were especially sensitive to forest disturbance. An important goal for the conservation of herpetofauna should be the determination of species traits associated with extinction or persistence in agricultural mosaics. Resumen:,Exploramos el impacto de la conversión de bosques a mosaico agrícola sobre ensambles de lagartijas, serpientes y tortugas de bosques Neotropicales secos. Durante 2 años muestreamos 6 cuencas pequeñas, 3 conservadas y 3 perturbadas, en la costa occidental de México. Las cuencas perturbadas se caracterizaron por un mosaico de pastizales y campos cultivados (maíz, frijol, calabaza) entremezclados con parches de bosque seco en diferentes etapas sucesionales. En cada cuenca, realizamos 11 búsquedas diurnas y nocturnas en 10 parcelas establecidas aleatoriamente. Consideramos los atributos de vulnerabilidad de especies en relación con la modificación del hábitat. Registramos 18 especies de lagartijas, 23 de serpientes y 3 de tortugas. Treinta y seis especies (58%) ocurrieron en ambas condiciones de bosque, y 14 (22%) y 12 (19%) especies solo ocurrieron en los sitios conservados y perturbados, respectivamente. Los ensambles respondieron a la perturbación de manera diferente. La riqueza de especies, la diversidad y la abundancia de lagartijas fueron mayores en los bosques perturbados. La diversidad y riqueza de especies de anuros fueron menores en el bosque perturbado pero la abundancia fue similar en ambas condiciones de bosque. La diversidad, riqueza de especies y abundancia de tortugas fueron menores en el bosque perturbado. La estructura y la composición de los ensambles de serpientes no difirieron entre condiciones de bosque. Consideramos que las especies eran sensibles a la perturbación si su abundancia fue significativamente menor en las áreas perturbadas. Cuatro (22%) especies de anuros, 2 (11%) de lagartijas y 3 (100%) de tortugas fueron sensibles a la perturbación. Ninguna especie de serpiente fue sensible. La declinación en la abundancia de especies sensibles a la perturbación se asoció con la reducción en la cobertura del dosel, de tallos leñosos, raíces y hojarasca. Las especies de anuros de cuerpo pequeño y desarrollo embrionario directo fueron especialmente sensibles a la perturbación del bosque. La determinación de atributos de las especies asociadas con su extinción o persistencia en mosaicos agrícolas debería ser una meta importante para la conservación de la herpetofauna. 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