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Greater Diversity (greater + diversity)
Selected AbstractsEcological relevance of laboratory determined temperature limits: colonization potential, biogeography and resilience of Antarctic invertebrates to environmental changeGLOBAL CHANGE BIOLOGY, Issue 11 2010D. K. A. BARNES Abstract The relevance of laboratory experiments in predicting effects of climate change has been questioned, especially in Antarctica where sea temperatures are remarkably stable. Laboratory studies of Southern Ocean marine animal capacities to survive increasing temperature mainly utilize rapid temperature elevations, 100 ×,10 000 × faster than sea temperature is predicted to rise. However, due to small-scale temperature fluctuations these studies may be crucial for understanding colonization patterns and predicting survival particularly through interactions between thermal tolerance and migration. The colonization of disjunct shelves around Antarctica by larvae or adult drift requires crossing or exposure to, rapid temperature changes of up to 2,4 °C over days to weeks. Analyses of responses to warming at varying rates of temperature change in the laboratory allow better predictions of the potential species have for colonizing disjunct shelf areas (such as the Scotia Arc). Inhabiting greater diversities of localities increases the geographic and thermal range species experience. We suggest a strong link between short-term temperature tolerance, environmental range and prospects for surviving changing environments. [source] Modelling the species richness distribution for French Aphodiidae (Coleoptera, Scarabaeoidea)ECOGRAPHY, Issue 2 2004Jorge M. Lobo The species richness distribution of the French Aphodiidae was predicted using Generalized Linear Models to relate the number of species to spatial, topographic and climate variables. The entire French territory was studied, divided into 301 0.72×0.36 degree grid squares; the model was developed using 66 grid squares previously identified as well sampled. After eliminating nine outliers, the final model accounted for 74.8% of total deviance with a mean Jackknife predictive error of 10.5%. Three richest areas could be distinguished: the western head (Brittany), southwestern France, and, to a lesser extent, the northeastern region. Sampling effort should now be focused on the western head, where no square was correctly sampled, and on southwestern France, which was recognised as a diversity hotspot, both for Aphodiidae and for Scarabaeidae. The largest fraction of variability (37%) in the number of species was accounted for by the combined effect of the three groups of explanatory variables. After controlling for the effect of significant climate and topographic variables, spatial variables still explain 27% of variation in species richness, suggesting the existence of a spatial pattern in the distribution of species richness (greater diversity in western France) that can not be explained by the environmental variables considered here. We hypothesize that this longitudinal spatial pattern is due to the relevance of a western colonization pathway along the glacial-interglacial cycles, as well as by the barrier effect played by the Alps. [source] Vertical distribution of picoeukaryotic diversity in the Sargasso SeaENVIRONMENTAL MICROBIOLOGY, Issue 5 2007Fabrice Not Summary Eukaryotic molecular diversity within the picoplanktonic size-fraction has primarily been studied in marine surface waters. Here, the vertical distribution of picoeukaryotic diversity was investigated in the Sargasso Sea from euphotic to abyssal waters, using size-fractionated samples (< 2 ,m). 18S rRNA gene clone libraries were used to generate sequences from euphotic zone samples (deep chlorophyll maximum to the surface); the permanent thermocline (500 m); and the pelagic deep-sea (3000 m). Euphotic zone and deep-sea data contrasted strongly, the former displaying greater diversity at the first-rank taxon level, based on 232 nearly full-length sequences. Deep-sea sequences belonged almost exclusively to the Alveolata and Radiolaria, while surface samples also contained known and putative photosynthetic groups, such as unique Chlorarachniophyta and Chrysophyceae sequences. Phylogenetic analyses placed most Alveolata and Stramenopile sequences within previously reported ,environmental' clades, i.e. clades within the Novel Alveolate groups I and II (NAI and NAII), or the novel Marine Stramenopiles (MAST). However, some deep-sea NAII formed distinct, bootstrap supported clades. Stramenopiles were recovered from the euphotic zone only, although many MAST are reportedly heterotrophic, making the observed distribution a point for further investigation. An unexpectedly high proportion of radiolarian sequences were recovered. From these, five environmental radiolarian clades, RAD-I to RAD-V, were identified. RAD-IV and RAD-V were composed of Taxopodida-like sequences, with the former solely containing Sargasso Sea sequences, although from all depth zones sampled. Our findings highlight the vast diversity of these protists, most of which remain uncultured and of unknown ecological function. [source] Molecular characterization of sulfate-reducing bacteria in a New England salt marshENVIRONMENTAL MICROBIOLOGY, Issue 8 2005Michele Bahr Summary Sulfate reduction, mediated by sulfate-reducing bacteria (SRB), is the dominant remineralization pathway in sediments of New England salt marshes. High sulfate reduction rates are associated with the rhizosphere of Spartina alterniflora when plants elongate aboveground. The growth process concurrently produces significant amounts of new rhizome material belowground and the plants leak dissolved organic compounds. This study investigated the diversity of SRB in a salt marsh over an annual growth cycle of S. alterniflora by exploring the diversity of a functional gene, dissimilatory sulfite reductase (dsrAB). Because the dsrAB gene is a key gene in the anaerobic sulfate-respiration pathway, it allows the identification of microorganisms responsible for sulfate reduction. Conserved dsrAB primers in polymerase chain reaction (PCR) generated full-length dsrAB amplicons for cloning and DNA sequence analysis. Nearly 80% of 380 clone sequences were similar to genes from Desulfosarcina and Desulfobacterium species within Desulfobacteraceae. This reinforces the hypothesis that complete oxidizers with high substrate versatility dominate the marsh. However, the phylotypes formed several clades that were distinct from cultured representatives, indicating a greater diversity of SRB than previously appreciated. Several dsrAB sequences were related to homologues from Gram-positive, thermophilic and non-thermophilic Desulfotomaculum species. One dsrAB lineage formed a sister group to cultured members of the delta-proteobacterial group Syntrophobacteraceae. A deeply branching dsrAB lineage was not affiliated with genes from any cultured SRB. The sequence data from this study will allow for the design of probes or primers that can quantitatively assess the diverse range of sulfate reducers present in the environment. [source] EVOLUTION OF INSECT METAMORPHOSIS: A MICROARRAY-BASED STUDY OF LARVAL AND ADULT GENE EXPRESSION IN THE ANT CAMPONOTUS FESTINATUSEVOLUTION, Issue 4 2005Michael A. D. Goodisman Abstract Holometabolous insects inhabit almost every terrestrial ecosystem. The evolutionary success of holometabolous insects stems partly from their developmental program, which includes discrete larval and adult stages. To gain an understanding of how development differs among holometabolous insect taxa, we used cDNA microarray technology to examine differences in gene expression between larval and adult Camponotus festinatus ants. We then compared expression patterns obtained from our study to those observed in the fruitfly Drosophila melanogaster. We found that many genes showed distinct patterns of expression between the larval and adult ant life stages, a result that was confirmed through quantitative reverse-transcriptase polymerase chain reaction. Genes involved in protein metabolism and possessing structural activity tended to be more highly expressed in larval than adult ants. In contrast, genes relatively upregulated in adults possessed a greater diversity of functions and activities. We also discovered that patterns of expression observed for homologous genes in D. melanogaster differed substantially from those observed in C. festinatus. Our results suggest that the specific molecular mechanisms involved in metamorphosis will differ substantially between insect taxa. Systematic investigation of gene expression during development of other taxa will provide additional information on how developmental pathways evolve. [source] Contemporary Models of Youth Development and Problem Prevention: Toward an Integration of Terms, Concepts, and ModelsFAMILY RELATIONS, Issue 1 2004Stephen Small Over the past several years, increased interest in preventing youth problems and promoting healthy youth development has led youth and family practitioners, policy makers, and researchers to develop a wide range of approaches based on various theoretical frameworks. Although the growth in guiding frameworks has led to more complex models and a greater diversity in the options available to scholars and practitioners, the lack of an integrative conceptual scheme and consistent terminology has led to some confusion in the field. Here, we provide an overview of three approaches to youth development and problem prevention, critically examine their strengths and weaknesses, and offer some elaborations to help clarify, extend, and integrate the models. We conclude by discussing some general implications for researchers, practitioners, and policy makers. [source] The crystal structure of phenylpyruvate decarboxylase from Azospirillum brasilense at 1.5 Å resolutionFEBS JOURNAL, Issue 9 2007Implications for its catalytic, regulatory mechanism Phenylpyruvate decarboxylase (PPDC) of Azospirillum brasilense, involved in the biosynthesis of the plant hormone indole-3-acetic acid and the antimicrobial compound phenylacetic acid, is a thiamine diphosphate-dependent enzyme that catalyses the nonoxidative decarboxylation of indole- and phenylpyruvate. Analogous to yeast pyruvate decarboxylases, PPDC is subject to allosteric substrate activation, showing sigmoidal v versus [S] plots. The present paper reports the crystal structure of this enzyme determined at 1.5 Å resolution. The subunit architecture of PPDC is characteristic for other members of the pyruvate oxidase family, with each subunit consisting of three domains with an open ,/, topology. An active site loop, bearing the catalytic residues His112 and His113, could not be modelled due to flexibility. The biological tetramer is best described as an asymmetric dimer of dimers. A cysteine residue that has been suggested as the site for regulatory substrate binding in yeast pyruvate decarboxylase is not conserved, requiring a different mechanism for allosteric substrate activation in PPDC. Only minor changes occur in the interactions with the cofactors, thiamine diphosphate and Mg2+, compared to pyruvate decarboxylase. A greater diversity is observed in the substrate binding pocket accounting for the difference in substrate specificity. Moreover, a catalytically important glutamate residue conserved in nearly all decarboxylases is replaced by a leucine in PPDC. The consequences of these differences in terms of the catalytic and regulatory mechanism of PPDC are discussed. [source] The diversification and extinction of Doushantuo-Pertatataka acritarchs in South China: causes and biostratigraphic significanceGEOLOGICAL JOURNAL, Issue 3-4 2007Zhou Chuanming Abstract The Ediacaran Period immediately follows the last Cryogenian glaciation,the ,635,Ma Marinoan or Nantuo glaciation, and it is also punctuated by another brief glaciation,the ,582,Ma Gaskiers glaciation. It is possible that these glaciations may have had significant impact on Ediacaran biological evolution (e.g. the appearance or disappearance of Doushantuo-Pertatataka acritarchs). Alternative hypotheses propose that the diversification of Doushantuo-Pertatataka acritarchs was caused by the Acraman bolide impact or by emerging eumetazoans. To test these hypotheses, high-resolution geochronological and biostratigraphic data are required. The Doushantuo Formation in South China, radiometrically constrained between ,635 and ,551,Ma, has the potential to clarify the global picture of early-middle Ediacaran evolution. Here we present preliminary biostratigraphic data from the Doushantuo Formation in the East Yangtze Gorges area and new ,13C chemostratigraphic data from the Doushantuo Formation at Weng'an. These and previously published palaeontological data, aided by the tool of ,13C chemostratigraphy, indicate that the biostratigraphic record of the Doushantuo Formation is locally sensitive to the availability of specific taphonomic windows. In the East Yangtze Gorges area, Doushantuo-Pertatataka acritarchs first appeared shortly after the termination of the Nantuo glaciation and gradually diversified throughout the Doushantuo Formation. At Weng'an, however, such acritarchs first appear,abruptly and in much greater diversity,in phosphorite of the upper Doushantuo Formation, immediately above a subaerial exposure surface. Thus, the biostratigraphic pattern in the East Yangtze Gorges area permits, whereas that at Weng'an apparently disallows, a causal relationship between the Nantuo glaciation and the diversification of Doushantuo-Pertatataka acritarchs. We conclude that the biostratigraphic record is incomplete at Weng'an, where the early Ediacaran evolutionary history is not preserved. The South China data indicate that special attention has to be paid to taphonomic and palaeoenvironmental analysis before extrapolating local and regional biostratigraphic ranges to make global interpretations. It is less clear when Doushantuo-Pertatataka acritarchs disappeared. Previous investigators have variously suggested that they disappeared before, at, or after, the Gaskiers glaciation. These hypotheses are difficult to test because of the lack of sedimentary evidence for the Gaskiers glaciation in South China and other regions (e.g. South Australia) where Doushantuo-Pertatataka acritarchs are abundant. In Australia, Doushantuo-Pertatataka acritarchs are thought to have experienced a sharp decline after the Egan glaciation, which may well be equivalent to the Gaskiers glaciation. If true, then Doushantuo-Pertatataka acritarchs are largely restricted to the interval between the Nantuo and Gaskiers glaciations. This conclusion allows us to place constraints on the possible causes of the diversification and extinction of Doushantuo-Pertatataka acritarchs and has important implications for the biostratigraphic significance of Doushantuo-Pertatataka acritarchs. Copyright © 2006 John Wiley & Sons, Ltd. [source] Variation in wood density determines spatial patterns inAmazonian forest biomassGLOBAL CHANGE BIOLOGY, Issue 5 2004Timothy R. Baker Abstract Uncertainty in biomass estimates is one of the greatest limitations to models of carbon flux in tropical forests. Previous comparisons of field-based estimates of the aboveground biomass (AGB) of trees greater than 10 cm diameter within Amazonia have been limited by the paucity of data for western Amazon forests, and the use of site-specific methods to estimate biomass from inventory data. In addition, the role of regional variation in stand-level wood specific gravity has not previously been considered. Using data from 56 mature forest plots across Amazonia, we consider the relative roles of species composition (wood specific gravity) and forest structure (basal area) in determining variation in AGB. Mean stand-level wood specific gravity, on a per stem basis, is 15.8% higher in forests in central and eastern, compared with northwestern Amazonia. This pattern is due to the higher diversity and abundance of taxa with high specific gravity values in central and eastern Amazonia, and the greater diversity and abundance of taxa with low specific gravity values in western Amazonia. For two estimates of AGB derived using different allometric equations, basal area explains 51.7% and 63.4%, and stand-level specific gravity 45.4% and 29.7%, of the total variation in AGB. The variation in specific gravity is important because it determines the regional scale, spatial pattern of AGB. When weighting by specific gravity is included, central and eastern Amazon forests have significantly higher AGB than stands in northwest or southwest Amazonia. The regional-scale pattern of species composition therefore defines a broad gradient of AGB across Amazonia. [source] Global patterns of genetic variation in plant species along vertical and horizontal gradients on mountainsGLOBAL ECOLOGY, Issue 2 2008Takafumi Ohsawa ABSTRACT Aim To understand global patterns of genetic variation in plant species on mountains and to consider the significance of mountains for the genetic structure and evolution of plant species. Location Global. Methods We review published studies. Results Genetic diversity within populations can vary along altitudinal gradients in one of four patterns. Eleven of 42 cited studies (26% of the total) found that populations at intermediate altitudes have greater diversity than populations at lower and higher altitudes. This is because the geographically central populations are under optimal environmental conditions, whereas the peripheral populations are in suboptimal situations. The second pattern, indicating that higher populations have less diversity than lower populations, was found in eight studies (19%). The third pattern, indicating that lower populations have lower diversity than higher populations, was found in 10 studies (24%). In 12 studies (29%), the intrapopulation genetic variation was found to be unaffected by altitude. Evidence of altitudinal differentiation was found in more than half of these studies, based on measurements of a range of variables including genome size, number of chromosomes or a range of loci using molecular markers. Furthermore, great variation has been found in phenotypes among populations at different altitudes in situ and in common garden experiments, even in cases where there was no associated variation in molecular composition. Mountains can be genetic barriers for species that are distributed at low elevations, but they can also provide pathways for species that occupy high-elevation habitats. [Correction added after publication 9 October 2007: ,less diversity' changed to ,greater diversity' in the second sentence of the Results section of the Abstract] Main conclusions Genetic diversity within populations can vary along altitudinal gradients as a result of several factors. The results highlight the importance of phenotypic examinations in detecting altitudinal differences. The influence of mountain ridges on genetic differentiation varies depending, inter alia, on the elevation at which the species occurs. Based on these findings, zoning by altitudes or ridges would be helpful for the conservation of tree populations with the onset of global warming. [source] The impact of managed competition on diversity, innovation and creativity in the delivery of home-care servicesHEALTH & SOCIAL CARE IN THE COMMUNITY, Issue 4 2008Glen E. Randall PhDArticle first published online: 28 JUN 200 Abstract Reforming publicly funded healthcare systems by introducing elements of competition, often by allowing for-profit providers to compete with not-for-profit providers, is a strategy that has become commonplace in Western democracies. It is widely thought that the competitive forces of the marketplace will lead to greater efficiency, diversity and even innovation in the delivery of services. Between 1997 and 2000, a model of ,managed competition' was introduced as a major reform to the delivery of home-care services in Ontario, Canada. It was expected that by allowing greater competition within the home-care sector, this model would constrain costs and encourage provider agencies to become more innovative and creative in meeting service delivery needs. The purpose of this case study is to explore the impact of the managed competition reform on the for-profit and the not-for-profit organisations that provided rehabilitation home-care services, and, more specifically, to assess the extent to which the goal of greater diversity, innovation and creativity was achieved following implementation of the reform. A purposive sample of 49 key informants were selected for in-depth interviews, and a survey of the 36 organisations that provided rehabilitation home-care services and the 43 community care access centres that purchased services from these provider agencies was conducted. Data were collected between November 2002 and May 2003. Findings demonstrate that a combination of coercive, mimetic and normative isomorphic pressures have constrained diversity, innovation and creativity within the home-care sector. The implication is that the features that have traditionally distinguished for-profit and not-for-profit provider agencies from each other are rapidly disappearing, and a new hybrid organisational structure is evolving. [source] Primary care in the UK: understanding the dynamics of devolutionHEALTH & SOCIAL CARE IN THE COMMUNITY, Issue 5 2001Mark Exworthy Abstract The United Kingdom is ostensibly one country and yet public policy often varies between its constituent territories , England, Scotland, Wales and Northern Ireland. Health policy illustrates the dilemmas inherent in an apparently unitary system that permits scope for territorial variation. Administrative devolution has now been accompanied by political devolution but their interaction has yet to produce policy outcomes. This paper describes recent health policy reform with regard to primary care in terms of the tension inherent in current policy between notions of a ,one nation NHS' and the territorial diversity wrought by devolution. The paper provides a framework for understanding the emergent outcomes by exploring various concepts. In particular, the existing character of territorial policy networks, the properties of policies in devolved territories and intergovernmental relations are considered from various disciplines to examine whether greater diversity or uniformity will result from the dual reform process. Whilst this evaluation can, at this stage, only be preliminary, the paper provides a framework to appraise the emerging impact of devolution upon primary care in the UK. [source] European dimensions to collective bargaining: new symmetries within an asymmetric process?INDUSTRIAL RELATIONS JOURNAL, Issue 4 2002Paul Marginson The impact of economic and monetary union on the structures, processes and agenda of collective bargaining at sector and company levels is explored. Drawing on cross,national evidence from two sectors, considerable differences between sectors within national boundaries are identified, but also some striking parallels within sectors across national boundaries. Convergence and greater diversity are simultaneously evident. [source] Renewed focus on the developing human neocortexJOURNAL OF ANATOMY, Issue 4 2010Gavin Clowry Abstract Many specifically human psychiatric and neurological conditions have developmental origins. Rodent models are extremely valuable for the investigation of brain development, but cannot provide insight into aspects that are specifically human. The human brain, and particularly the cerebral cortex, has some unique genetic, molecular, cellular and anatomical features, and these need to be further explored. Cortical expansion in human is not just quantitative; there are some novel types of neurons and cytoarchitectonic areas identified by their gene expression, connectivity and functions that do not exist in rodents. Recent research into human brain development has revealed more elaborated neurogenetic compartments, radial and tangential migration, transient cell layers in the subplate, and a greater diversity of early-generated neurons, including predecessor neurons. Recently there has been a renaissance of the study of human brain development because of these unique differences, made possible by the availability of new techniques. This review gives a flavour of the recent studies stemming from this renewed focus on the developing human brain. [source] Breeding birds on small islands: island biogeography or optimal foraging?JOURNAL OF ANIMAL ECOLOGY, Issue 2 2006GARETH J. RUSSELL Summary 1We test MacArthur and Wilson's theory about the biogeography of communities on isolated habitat patches using bird breeding records from 16 small islands off the coasts of Britain and Ireland. 2A traditional examination of patterns of species richness on these islands suggests that area and habitat diversity are important predictors, but that isolation and latitude have a negligible impact in this system. 3Unlike traditional studies, we directly examine the fundamental processes of colonization and local extinction (cessation of breeding), rather than higher-order phenomena such as species richness. 4We find that many of MacArthur and Wilson's predictions hold: colonization probability is lower on more isolated islands, and extinction probability is lower on larger islands and those with a greater diversity of habitats. 5We also find an unexpected pattern: extinction probability is much lower on more isolated islands. This is the strongest relationship in these data, and isolation is the best single predictor of colonization and extinction. 6Our results show that examination of species richness alone is misleading. Isolation has a strong effect on both of the dynamic processes that underlie richness, and in this system, the reductions in both colonization and extinction probability seen on more distant islands have opposing influences on species richness, and largely cancel each other out. 7We suggest that an appropriate model for this system might be optimal foraging theory, which predicts that organisms will stay longer in a resource patch if the distance to a neighbouring patch is large. If nest sites and food are the resources in this system, then optimal foraging theory predicts the pattern we observe. 8We advance the hypothesis that there is a class of spatial systems, defined by their scale and by the taxon under consideration, at which decision-making processes are a key driver of the spatiotemporal dynamics. The appropriate theory for such systems will be a hybrid of concepts from biogeography/metapopulation theory and behavioural ecology. [source] Phylogeographic structuring and volant mammals: the case of the pallid bat (Antrozous pallidus)JOURNAL OF BIOGEOGRAPHY, Issue 7 2007Sarah E. Weyandt Abstract Aim, To examine the phylogeographic pattern of a volant mammal at the continental scale. The pallid bat (Antrozous pallidus) was chosen because it ranges across a zone of well-studied biotic assemblages, namely the warm deserts of North America. Location, The western half of North America, with sites in Mexico, the United States, and Canada. Methods, PCR amplification and sequencing of the mitochondrial control region was performed on 194 pallid bats from 36 localities. Additional sequences at the cytochrome- b locus were generated for representatives of each control-region haplotype. modeltest was used to determine the best set of parameters to describe each data set, which were incorporated into analyses using paup*. Statistical parsimony and measurements of population differentiation (amova, FST) were also used to examine patterns of genetic diversity in pallid bats. Results, We detected three major lineages in the mitochondrial DNA of pallid bats collected across the species range. These three major clades have completely non-overlapping geographic ranges. Only 6 of 80 control-region haplotypes were found at more than a single locality, and sequences at the more conserved cytochrome- b locus revealed 37 haplotypes. Statistical parsimony generated three unlinked networks that correspond exactly to clades defined by the distance-based analysis. On average there was c. 2% divergence for the combined mitochondrial sequences within each of the three major clades and c. 7% divergence between each pair of clades. Molecular clocks date divergence between the major clades at more than one million years, on average, using the faster rates, and at more than three million years using more conservative rates of evolution. Main conclusions, Divergent haplotypic lineages with allopatric distributions suggest that the pallid bat has responded to evolutionary pressures in a manner consistent with other taxa of the American southwest. These results extend the conclusions of earlier studies that found the genetic structuring of populations of some bat species to show that a widespread volant species may comprise a set of geographically replacing monophyletic lineages. Haplotypes were usually restricted to single localities, and the clade showing geographic affinities to the Sonoran Desert contained greater diversity than did clades to the east and west. While faster molecular clocks would allow for glacial cycles of the Pleistocene as plausible agents of diversification of pallid bats, evidence from co-distributed taxa suggests support for older events being responsible for the initial divergence among clades. [source] Alternative technologies for biotechnological fuel ethanol manufacturingJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 8 2007Alain A Vertès Abstract The challenges of implementing biorefineries on a global scale include socioeconomic, financial, and technological constraints. In particular, the development of biorefineries is tightly linked to the continued availability of fermentation raw materials. These constraints can be relaxed by the use of diverse raw materials, while advances that confer higher flexibility would enable biotechnological plant managers to swiftly react to volatile markets. In conventional processes, Saccharomyces cerevisiae grows on a relatively limited range of substrates, and produces only a single product,ethanol. Given the observed maturity of the S. cerevisiae fermentation technology, alternatives to baker's yeast may be needed to tip the economic balance in favour of biotechnological ethanol. These alternative fermentation technologies may allow a greater diversity of substrates to be used to produce an individually tailored mix of ethanol and other chemicals. Copyright © 2007 Society of Chemical Industry [source] Aziridines as templates: A general strategy for the stereospecific synthesis of 2-azetidinonesJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 1 2006S. D. Sharma Various routes to a variety of azridine-2-carboxylates have been described and the stereochemistry of these compounds has been determined by spectroscopic methods. Further, greater diversity of ,-lactams via ring expansion of these azridines-2-carboxylates were obtained by a general, efficient and direct stereospecific approach. [source] Diversity in the Judiciary: The Case For Positive ActionJOURNAL OF LAW AND SOCIETY, Issue 3 2009Kate Malleson A range of policies has been developed in England and Wales to reform the judicial appointments process so as to promote greater diversity. But despite two decades of official activity, the pace of change has been far slower than anticipated. Increasing awareness of the intransigence of the problem has led to a greater willingness to revisit some of the more fundamental tenets which have underpinned the approach to the problem to date, in particular, the unquestioning and inflexible commitment to the principle of equal treatment. This article examines the different forms of positive action which might play a part in the development of new diversity strategies for the judiciary. It reviews the arguments for and against different types, in terms of effectiveness, quality of appointments, and equity. It goes on to consider the legal frameworks which govern diversity and equality policies and assesses the legal implications of adopting different forms of positive action. [source] QUANTITATIVE ANALYSIS OF SHAPE VARIATION IN TYPE AND MODERN POPULATIONS OF MERIDION (BACILLARIOPHYCEAE)JOURNAL OF PHYCOLOGY, Issue 1 2001Kristina M. Rhode Subtle differences in valve morphology can indicate sexually isolated populations in diatoms (Bacillariophyceae). Shape descriptors, like Legendre coefficients, have been used to quantify differences in valve outline so that morphologically distinct groups can be recognized. Legendre coefficients were used as shape descriptors to quantify differences in valve outline among five populations in the genus Meridion Ag. Two novel populations of Meridion from North America, a North American population of M. constrictum Ralfs, type material for M. circulare (Greve.) Ag., and type material of M. constrictum were included in this analysis. Results of a principle components analysis and discriminate analyses on the shape descriptors of all five populations support the hypotheses that the two novel North American populations are undescribed taxa within Meridion and that the North American M. constrictum can be considered Meridion constrictum sensu stricto. A new taxon, Meridion hohii Rhode, is described. There appears to be greater diversity within the genus Meridion than is currently recognized. [source] Electronic nose analysis of volatile compounds from poultry meat samples, fresh and after refrigerated storage,JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 3 2002Dorothy D, H Boothe Abstract Electronic nose technology has previously been applied to the assessment of the quality of red meats, pork and fish, but not poultry products. In the present study the ability of the electronic nose to assess the microbiological quality of raw poultry meat as a function of storage time and temperature was investigated. Four types of chicken pieces (boneless breast with and without skin, wings and thighs) were stored for up to 2 days at 13,°C (the maximum allowable temperature in poultry processing environments) or for up to 5 days at 4,°C (refrigeration temperature for raw poultry products prior to shipping or further processing). Saline rinses of meat samples were serially diluted in tryptic soy broth to 10,10. The rinses and their associated serial dilutions were analysed on an electronic nose with 12 metal oxide sensors in order to determine the specificity and sensitivity respectively of the assay. Principal component analysis (PCA) maps of the data confirmed that the electronic nose could differentiate volatile compounds associated with individual types of meat samples properly stored at 4,°C from those maintained at processing temperature, 13,°C, for a comparable time, even as early as day 1 of storage. Differences in headspace gases from any type of meat sample stored at one temperature could also be determined with increased storage time. However, data from samples stored at 4,°C clustered more tightly in PCA maps than those associated with samples maintained at 13,°C, indicating a greater diversity in volatile compounds at the higher temperature. We have shown herein that the electronic nose can detect changes in the volatile compounds associated with chicken meat based on product storage time and temperature; the technology can assess length of sample storage as well as deviation from refrigeration temperature. Published in 2002 for SCI by John Wiley & Sons, Ltd. [source] Recognizing diversity in coral symbiotic dinoflagellate communitiesMOLECULAR ECOLOGY, Issue 6 2007AMY M. APPRILL Abstract A detailed understanding of how diversity in endosymbiotic dinoflagellate communities maps onto the physiological range of coral hosts is critical to predicting how coral reef ecosystems will respond to climate change. Species-level taxonomy of the dinoflagellate genus Symbiodinium has been predominantly examined using the internal transcribed spacer (ITS) region of the nuclear ribosomal array (rDNA ITS2) and downstream screening for dominant types using denaturing gradient gel electrophoresis (DGGE). Here, ITS2 diversity in the communities of Symbiodinium harboured by two Hawaiian coral species was explored using direct sequencing of clone libraries. We resolved sixfold to eightfold greater diversity per coral species than previously reported, the majority of which corresponds to a novel and distinct phylogenetic lineage. We evaluated how these sequences migrate in DGGE and demonstrate that this method does not effectively resolve this diversity. We conclude that the Porites spp. examined here harbour diverse assemblages of novel Symbiodinium types and that cloning and sequencing is an effective methodological approach for resolving the complexity of endosymbiotic dinoflagellate communities harboured by reef corals. [source] A NEW SEA SPIDER (ARTHROPODA: PYCNOGONIDA) WITH A FLAGELLIFORM TELSON FROM THE LOWER DEVONIAN HUNSRÜCK SLATE, GERMANYPALAEONTOLOGY, Issue 5 2006MARKUS POSCHMANN Abstract:, A new Lower Devonian sea spider (Arthropoda: Pycnogonida) from the Hunsrück Slate, Germany, is described as Flagellopantopus blocki gen. et sp. nov. This is only the sixth fossil pycnogonid species to be described. Its most remarkable and unique aspect is the long, flagelliform telson. Although our fossil apparently lacks chelifores (an apomorphy), the retained telson and the segmented trunk end behind the last pair of legs resolve F. blocki to a fairly basal position in the pycnogonid stem lineage. It probably lies between Palaeoisopus problematicus Broili, which has a lanceolate telson and the most trunk segments of any sea spider, and all other Silurian,Recent Pycnogonida. Our new material shows that at least two fossil pycnogonids retained a telson, albeit with very different morphologies, and further supports the idea that a greater diversity of body plans existed among the Palaeozoic pycnogonid taxa. [source] Electrospray liquid chromatography/mass spectrometry fingerprinting of Acanthophis (death adder) venoms: taxonomic and toxinological implicationsRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 6 2002Bryan G. Fry Death adders (genus Acanthophis) are unique among elapid snakes in both morphology and venom composition. Despite this genus being among the most divergent of all elapids, the venom has been historically regarded as relatively quite simple. In this study, liquid chromatography/mass spectrometry (LC/MS) analysis has revealed a much greater diversity in venom composition, including the presence of molecules of novel molecular weights that may represent a new class of venom component. Furthermore, significant variation exists between species and populations, which allow for the LC/MS fingerprinting of each species. Mass profiling of Acanthophis venoms clearly demonstrates the effectiveness of this technique which underpins fundamental studies ranging from chemotaxonomy to drug design. Copyright © 2002 John Wiley & Sons, Ltd. [source] Comparison of ADHD symptom subtypes as source-specific syndromesTHE JOURNAL OF CHILD PSYCHOLOGY AND PSYCHIATRY AND ALLIED DISCIPLINES, Issue 6 2004Kenneth D. Gadow Background:, This study examines differences between the three subtypes of attention-deficit/hyperactivity disorder (ADHD), inattentive (I), hyperactive-impulsive (H), and combined (C), in a heterogeneous sample of 248 boys (ages 6 to 10 years) with emotional and behavioral problems who were recruited for participation in a diagnostic study. Method:, The boys and their mothers participated in an extensive evaluation that involved multiple assessments of cognitive, behavioral, academic, and family functioning. ADHD subtypes were defined on the basis of teacher alone, mother alone, and mother/teacher ratings of DSM-IV symptoms. Results:, Results indicated ADHD symptom groups showed a differential pattern of impairment socially (H,C>I) and cognitively (I,C>H). The C and H groups were the most and least impaired overall, respectively, and all subtypes were differentiated from the nonADHD clinical control or NONE (N) group in a manner consistent with the primary findings. External validation of group differences was limited, and there were marked inconsistencies in the pattern of findings depending on how groups were defined. For the most part, although the mother/teacher grouping strategy (compared with either alone) captured a greater diversity of differences between subtypes, it also obscured some. Conclusions:, Observed findings are consistent with the notion that mothers and teachers interpret symptom statements in terms of behaviors that are most relevant for their daily concerns. [source] Floristic diversity in fragmented Afromontane rainforests: Altitudinal variation and conservation importanceAPPLIED VEGETATION SCIENCE, Issue 3 2010Christine B. Schmitt Abstract Question: How does the floristic diversity of Afromontane rainforests change along an altitudinal gradient? What are the implications for conservation planning in these strongly fragmented forest areas that form part of the Eastern Afromontane Biodiversity Hotspot? Location: Bonga, southwestern Ethiopia. Methods: Based on evidence from other montane forests, we hypothesized that altitude has an effect on the floristic diversity of Afromontane rainforests in southwestern Ethiopia. To test this hypothesis, detailed vegetation surveys were carried out in 62 study plots located in four relatively undisturbed forest fragments situated at altitudes between 1600 m and 2300 m. Floristic diversity was evaluated using a combination of multivariate statistical analyses and diversity indices. Results: Ordination and indicator species analyses showed gradual variations in floristic diversity along the altitudinal gradient with a pronounced shift in species composition at ca. 1830 m. Upper montane forest (>1830 m) is characterized by high fern diversity and indicator species that are Afromontane endemics. Lower montane forest (<1830 m) exhibits a greater diversity of tree species and a higher abundance of the flagship species Coffea arabica. Conclusions: Our results provide crucial ecological background information concerning the montane rainforests of Ethiopia, which have been poorly studied until now. We conclude that both forest types identified during this study need to be considered for conservation because of their particular species compositions. Owing to the high degree of forest fragmentation, conservation concepts should consider a multi-site approach with at least two protected areas at different altitudinal levels. [source] Benchmarking habitat quality: observations using River Habitat Survey on near-natural streams and rivers in northern and western EuropeAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue S1 2010Paul J. Raven Abstract 1.Some ecological effects of physically modifying rivers are still unclear, partly due to scale factors, but also because the character of high quality habitat is poorly understood. 2.Surveys at 278 sites on 141 near-natural streams and rivers in northern and western Europe were carried out between 1994 and 2009 to benchmark the habitat quality assessment system used for River Habitat Survey (RHS). 3.The objectives were to establish if RHS was suitable outside the UK, investigate if 500 m was still valid as the survey length, suggest a benchmarking strategy and recommend improvements to habitat quality assessment protocols. 4.Some modifications to RHS are needed to take account of differences in hydrological conditions, land-use and, most importantly, riparian habitat structure found in mainland Europe. 5.On average, 82,87% of channel attributes and 87,98% of channel and bank features were recorded within the first of consecutive RHS sites, confirming that 500 m is an effective sample length for characterizing small rivers. 6.Stream-flow character appeared to influence the distribution of several in-channel features, with greater diversity and between-site variation associated with rivers of mixed flow-types. To account for local variation and for effective use of survey time, it is recommended that two or more consecutive RHS sites are used for benchmarking purposes. 7.A suite of assessment protocols with agreed criteria and analytical rules, linked to specific objectives (e.g. nature conservation, geomorphic condition), is needed to establish the character and habitat quality of rivers in a consistent fashion. 8.A multi-discipline benchmarking programme using hydro-ecological regions in Europe would build on existing knowledge and help to improve both the inter-calibration and local application of quality assessment protocols. Data-sharing by hydrologists, river ecologists and fluvial geomorphologists would improve the basis for managing rivers in support of the European Water Framework Directive and Habitats Directive. Copyright © 2010 John Wiley & Sons, Ltd. [source] The identification, characterization and conservation value of isoetid lakes in IrelandAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 3 2009Gary Free Abstract 1.Soft-water, oligotrophic isoetid lakes are vulnerable to eutrophication, acidification and alkalinization. As a result of these pressures a large proportion have undergone substantial deterioration in several European countries. The understanding of these systems has been limited by either a lack of lakes close to natural conditions or through receiving less focus in broader scale macrophyte surveys. This has resulted in a dearth of information on specific lake types in their natural condition. Sixty-eight soft-water lakes in Ireland were studied in order to achieve a better understanding of the biological and environmental conditions defining such lakes. 2.Eight groups of lakes were identified using cluster analysis and indicator species analysis. Three groups were representative of isoetid-rich lakes displaying a high frequency of occurrence of Isoetes lacustris, Lobelia dortmanna or Eriocaulon aquaticum together with the almost ubiquitous Littorella uniflora. Canonical variates analysis indicated that alkalinity, total phosphorus (TP), catchment area, altitude, moors and heathlands, mean transect depth, colour and lake area were significant variables discriminating among the eight groups. Soft-water lakes with high amounts of isoetids tended to be less exposed, have broad shallow littoral zones with a high transparency and be situated in smaller catchments. Total phosphorus and alkalinity were typically low, although one group of isoetid-rich lakes had higher mean TP and alkalinity values. This group may contain lakes under threat from nutrient enrichment and alkalinization and also lakes that have higher TP and alkalinity naturally. 3.Lakes with a prevalence of isoetids supported a greater diversity of macrophytes and chironomids indicating that such lakes may represent suitable conservation targets as they act as surrogates for soft-water lakes of high biodiversity. Other factors favouring a focus on isoetids in conservation strategies are their importance as a functional component in soft-water lakes and their sensitivity to lake and catchment environmental change. Copyright © 2008 John Wiley & Sons, Ltd. [source] Geophysical investigation of the site of the former monastic settlement, Clonard, County Meath, IrelandARCHAEOLOGICAL PROSPECTION, Issue 1 2006Paul J. Gibson Abstract Clonard, in County Meath, Ireland was a major ecclesiastical centre from the early sixth century to the twelfth century and buildings associated with the monastery were in existence until the late eighteenth century. However, today no extant buildings or features associated with the monastery are known. The geophysical investigation undertaken in this project has uncovered many anomalies which may be related to the monastic settlement at Clonard. A significant number of linear anomalies have been detected east of St Finian's church using magnetic gradiometry and twin electrode resistance surveying. Many of these anomalies are probably field boundaries; however, a much greater diversity of geophysical responses is located south and west of St Finian's church. A subsquare enclosure of 60,m sides is adjacent to a 300,m long palaeochannel. A fine network of intersecting low resistance anomalies probably represent former artificial drainage channels. Three large areas associated with anomalous magnetic readings were located which might indicate sites of human activity. In addition, there are four distinct zones which have large concentrations of high resistance values suggesting the presence of walls or buildings. Resistivity and ground-penetrating radar depth slices show that one of these zones has characteristics which indicate the presence of an east,west aligned building approximately 7,m wide in a north,south direction and about 15,m long in an east,west direction. Copyright © 2005 John Wiley & Sons, Ltd. [source] Microbial communities of ultramafic soils in maquis and rainforest at Mont Do, New CaledoniaAUSTRAL ECOLOGY, Issue 5 2009MELISSA LENCZEWSKI Abstract We analysed variation in microbial community richness and function in soils associated with a fire-induced vegetation successional gradient from low maquis (shrubland) through tall maquis to rainforest on metal-rich ultramafic soils at Mt Do, New Caledonia. Random amplified polymorphic DNA fingerprinting was used to determine the extent of genetic relatedness among the microbial communities and indicated that the open and tall maquis microbial communities were more similar to each other than they were to the rainforest community. Sole-source carbon utilization indicated variation in the microbial communities, again with greater diversity in rainforest soils. Plate counts showed that both rainforest and maquis soils contained bacteria that can grow in the presence of up to 20 mmol L,1 nickel and 10 mmol L,1 chromium. Understanding microbial community composition and dynamics in these ultramafic soils may lead to a better understanding of the processes facilitating vegetation succession from shrubland to forest on these high-metal substrates, and of approaches to successful revegetation following mining for metals including nickel, chromium and cobalt. [source] | |||||||||||||||||||||||||