Global Distribution (global + distribution)

Distribution by Scientific Domains
Distribution within Life Sciences


Selected Abstracts


Global distribution of the European species of the lichen genus Melanelia Essl.

JOURNAL OF BIOGEOGRAPHY, Issue 7 2005
Volker Otte
Abstract Aim, The global distribution of the European species of Melanelia Essl. (Lichenes: Parmeliaceae) was investigated in order to understand their distribution patterns against the background of ecogeographical and historical factors. Location, The location of the study is global, with a local emphasis on Europe. Methods, Geographical distribution and ecology of the species were investigated on the basis of herbarium studies and data from the literature as well as field observations. Distribution maps were created with ArcView GIS. The distribution patterns are expressed as three-dimensional ,areal formulas', regarding zonal distribution, altitudinal range and oceanicity, using a previously described method. The observed distribution patterns are discussed on the basis of their analogies with vascular plants and with respect to the ecogeographical vs. historical factors reflected by them. Results, With the exception of one species that is endemic to Europe, all species studied occur in both northern continents. A number of species have tropical-alpine outposts, and two species occur also in extratropical zones of the southern hemisphere. Arctic and boreal distributions are circumpolar, while in the southern holarctic zones an affinity to the western sides of both northern continents is frequent. Main conclusions, The distribution patterns appear to be mainly determined by contemporary ecogeographical factors. Most species probably have largely filled their potential distribution, at least within the Holarctic. Thus, the geographical origin and dispersal history of a species cannot reliably be reconstructed; they can be dissimilar in different species with similar distributions. [source]


Global distribution and reduced penetrance: Lrrk2 R1441C in an Irish Parkinson's disease kindred

MOVEMENT DISORDERS, Issue 2 2007
David Gosal MD
[source]


An Adaptive Sampling Scheme for Out-of-Core Simplification

COMPUTER GRAPHICS FORUM, Issue 2 2002
Guangzheng Fei
Current out-of-core simplification algorithms can efficiently simplify large models that are too complex to be loaded in to the main memory at one time. However, these algorithms do not preserve surface details well since adaptive sampling, a typical strategy for detail preservation, remains to be an open issue for out-of-core simplification. In this paper, we present an adaptive sampling scheme, called the balanced retriangulation (BR), for out-of-core simplification. A key idea behind BR is that we can use Garland's quadric error matrix to analyze the global distribution of surface details. Based on this analysis, a local retriangulation achieves adaptive sampling by restoring detailed areas with cell split operations while further simplifying smooth areas with edge collapse operations. For a given triangle budget, BR preserves surface details significantly better than uniform sampling algorithms such as uniform clustering. Like uniform clustering, our algorithm has linear running time and small memory requirement. [source]


Prediction and validation of the potential global distribution of a problematic alien invasive species , the American bullfrog

DIVERSITY AND DISTRIBUTIONS, Issue 4 2007
Gentile Francesco Ficetola
ABSTRACT Predicting the probability of successful establishment and invasion of alien species at global scale, by matching climatic and land use data, is a priority for the risk assessment. Both large- and local-scale factors contribute to the outcome of invasions, and should be integrated to improve the predictions. At global scale, we used climatic and land use layers to evaluate the habitat suitability for the American bullfrog Rana catesbeiana, a major invasive species that is among the causes of amphibian decline. Environmental models were built by using Maxent, a machine learning method. Then, we integrated global data with information on richness of native communities and hunting pressure collected at the local scale. Global-scale data allowed us to delineate the areas with the highest suitability for this species. Predicted suitability was significantly related to the invasiveness observed for bullfrog populations historically introduced in Europe, but did not explain a large portion of variability in invasion success. The integration of data at the global and local scales greatly improved the performance of models, and explained > 57% of the variance in introduction success: bullfrogs were more invasive in areas with high suitability and low hunting pressure over frogs. Our study identified the climatic factors entailing the risk of invasion by bullfrogs, and stresses the importance of the integration of biotic and abiotic data collected at different spatial scales, to evaluate the areas where monitoring and management efforts need to be focused. [source]


The fundamental and realized niche of the Monterey Pine aphid, Essigella californica (Essig) (Hemiptera: Aphididae): implications for managing softwood plantations in Australia

DIVERSITY AND DISTRIBUTIONS, Issue 4 2004
Trudi N. Wharton
ABSTRACT Essigella californica is a pine aphid native to western North America. In Australia, E. californica is considered an invasive pest that has the potential to cause severe economic loss to the Australian forestry industry. Two CLIMEX models were developed to predict the Australian and global distribution of E. californica under current climate conditions based upon the aphid's known North American distribution. The first model (model I) was fitted using the reasonably contiguous set of location records in North America that constituted the known range of E. californica, and excluded consideration of a single (reliable) location record of the aphid in southern Florida. The second model (model II) was fitted using all known records in North America. Model I indicated that the aphid would be climatically restricted to the temperate, Mediterranean and subtropical climatic regions of Australia. In northern Australia it would be limited by hot, wet conditions, while in more central areas of Australia it is limited by hot, dry conditions. Model II is more consistent with the current Australian distribution of E. californica. The contrast in geographical range and climatic conditions encompassed between the two models appears to represent the difference between the realized niche (model I) and fundamental niche (model II) of E. californica. The difference may represent the strength of biotic factors such as host limitation, competition and parasitism in limiting geographical spread in the native range. This paper provides a risk map for E. californica colonization in Australia and globally. E. californica is likely to remain a feature of the Australian pine plantations, and any feasibility studies into establishing coniferous plantations in lower rainfall areas should consider the likely impact of E. californica. [source]


Influence of feeding ecology on blood mercury concentrations in four species of turtles

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 8 2007
Christine M. Bergeron
Abstract Mercury is a relatively well-studied pollutant because of its global distribution, toxicity, and ability to bioaccumulate and biomagnify in food webs; however, little is known about bioaccumulation and toxicity of Hg in turtles. Total Hg (THg) concentrations in blood were determined for 552 turtles representing four different species (Chelydra serpentina, Sternotherus odoratus, Chrysemys picta, and Pseudemys rubriventris) from a Hg-contaminated site on the South River (VA, USA) and upstream reference sites. Methylmercury and Se concentrations also were determined in a subset of samples. Because the feeding ecology of these species differs drastically, stable isotopes of carbon (,13C) and nitrogen (,15N) were employed to infer the relationship between relative trophic position and Hg concentrations. Significant differences were found among sites and species, suggesting that blood can be used as a bioindicator of Hg exposure in turtles. We found differences in THg concentrations in turtles from the contaminated site that were consistent with their known feeding ecology: C. serpentina , S. odoratus > C. picta > P. rubriventris. This trend was generally supported by the isotope data, which suggested that individual turtles were feeding at more than one trophic level. Methylmercury followed similar spatial patterns as THg and was the predominant Hg species in blood for all turtles. Blood Se concentrations were low in the system, but a marginally positive relationship was found between THg and Se when species were pooled. The blood THg concentrations for the turtles in the present study are some of the highest reported in reptiles, necessitating further studies to investigate potential adverse effects of these high concentrations. [source]


Global statistical analysis of MISR aerosol data: a massive data product from NASA's Terra satellite

ENVIRONMETRICS, Issue 7 2007
Tao Shi
Abstract In climate models, aerosol forcing is the major source of uncertainty in climate forcing, over the industrial period. To reduce this uncertainty, instruments on satellites have been put in place to collect global data. However, missing and noisy observations impose considerable difficulties for scientists researching the global distribution of aerosols, aerosol transportation, and comparisons between satellite observations and global-climate-model outputs. In this paper, we fit a Spatial Mixed Effects (SME) statistical model to predict the missing values, denoise the observed values, and quantify the spatial-prediction uncertainties. The computations associated with the SME model are linear scalable to the number of data points, which makes it feasible to process massive global satellite data. We apply the methodology, which is called Fixed Rank Kriging (FRK), to the level-3 Aerosol Optical Depth (AOD) dataset collected by NASA's Multi-angle Imaging SpectroRadiometer (MISR) instrument flying on the Terra satellite. Overall, our results were superior to those from non-statistical methods and, importantly, FRK has an uncertainty measure associated with it that can be used for comparisons over different regions or at different time points. Copyright 2007 John Wiley & Sons, Ltd. [source]


Ciliate biogeography in Antarctic and Arctic freshwater ecosystems: endemism or global distribution of species?

FEMS MICROBIOLOGY ECOLOGY, Issue 2 2007
Wolfgang Petz
Abstract Ciliate diversity was investigated in situ in freshwater ecosystems of the maritime (South Shetland Islands, mainly Livingston Island, 63S) and continental Antarctic (Victoria Land, 75S), and the High Arctic (Svalbard, 79N). In total, 334 species from 117 genera were identified in both polar regions, i.e. 210 spp. (98 genera) in the Arctic, 120 spp. (73 genera) in the maritime and 59 spp. (41 genera) in the continental Antarctic. Forty-four species (13% of all species) were common to both Arctic and Antarctic freshwater bodies and 19 spp. to both Antarctic areas (12% of all species). Many taxa are cosmopolitans but some, e.g. Stentor and Metopus spp., are not, and over 20% of the taxa found in any one of the three areas are new to science. Cluster analysis revealed that species similarity between different biotopes (soil, moss) within a study area was higher than between similar biotopes in different regions. Distinct differences in the species composition of freshwater and terrestrial communities indicate that most limnetic ciliates are not ubiquitously distributed. These observations and the low congruence in species composition between both polar areas, within Antarctica and between high- and temperate-latitude water bodies, respectively, suggest that long-distance dispersal of limnetic ciliates is restricted and that some species have a limited geographical distribution. [source]


Subtropical cold surges: regional aspects and global distribution

INTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 10 2001
Ren D. Garreaud
Abstract Shallow surges of cold dry air are frequently observed to the east of the major mountain ranges, moving from mid-latitudes well into the Tropics in about 4 days. Because of their strong impact on weather, regional aspects of cold surges have received considerable attention, particularly over Southeast Asia, to the east of the Rockies and Mexican Sierras, and to the east of the subtropical Andes. Both observational and numerical studies reveal a similar structure and evolution of cold surges in different regions. These common aspects are reviewed in this work, as well as the mechanisms responsible for the development and subsequent advance of cold surges over the subtropics. Atmospheric reanalysis data are used to document the global distribution of cold surges on the basis of their continental-scale imprints on relevant fields, as well as to estimate their contribution on the regional and global energy balances. It is found that cold surges have a major cooling and drying effect over the regions where they are prevalent (e.g. subtropical South America) and represent a sizeable sink of energy for the Tropics. Copyright 2001 Royal Meteorological Society [source]


On the global distribution and dissemination of knowledge

INTERNATIONAL SOCIAL SCIENCE JOURNAL, Issue 195 2009
Nico Stehr
Our article centres on the question in the sense in which it may be possible to speak of global knowledge, in the first instance. Is it the necessary outcome and the intellectual mark of an age of globalising knowledge societies or is the global demand for the dissemination of knowledge systems trying to answer universally perceived problems? What changes occur to knowledge as it travels and for whom does its globalisation yield benefit or harm? Knowledge must be differentiated from mere information and its locally embedded nature poses serious challenges to opportunities and obstacles for its horizontal and vertical dissemination. Further, global worlds of knowledge raise questions over the ownership of knowledge. Intellectual property claims should be discussed with reference to opposing views, such as those concerning the thesis of knowledge's self-protective character. Some political and certain idealistic conceptions regard knowledge as common property par excellence. While trade in services and products as well as the digital communications revolution are identified as major vehicles for the dissemination of knowledge, it is yet an open question as to whether they will result in the unhindered dissemination of knowledge or in concentrating it. The second section of the article overviews and introduces the articles in this volume. [source]


DESCRIPTION OF A NEW GENUS OF PFIESTERIA -LIKE DINOFLAGELLATE, LUCIELLA GEN.

JOURNAL OF PHYCOLOGY, Issue 4 2007
INCLUDING TWO NEW SPECIES: LUCIELLA MASANENSIS SP., NOV. (DINOPHYCEAE)
A new genus of Pfiesteria -like heterotrophic dinoflagellate, Luciella gen. nov., and two new species, Luciella masanensis sp. nov. and Luciella atlantis sp. nov., are described. These species commonly occur with other small (<20 ,m) heterotrophic and mixotrophic dinoflagellates in estuaries from Florida to Maryland and the southern coast of Korea, suggesting a possible global distribution. An SEM analysis indicates that members of the genus Luciella have the enhanced Kofoidian plate formula of Po, cp, X, 4,, 2a, 6,, 6c, PC, 5+s, 5,, 0p, and 2,,. The two four-sided anterior intercalary plates are diamond shaped. The genus Luciella differs from the other genera in the Pfiesteriaceae by a least one plate in the plate tabulation and in the configuration of the two anterior intercalary plates. An SSU rDNA phylogenetic analysis confirmed the genus as monophyletic and distinct from the other genera in the Pfiesteriaceae. The morphology of Luciella masanensis closely resembles Pfiesteria piscicida Steid. et J. M. Burkh. and other Pfiesteria -like dinoflagellates in size and shape, making it easily misidentified using LM. Luciella atlantis, in contrast, has a more distinctive morphology. It can be distinguished from L. masanensis and other Pfiesteria -like organisms by a larger cell size, a more conical-shaped epitheca and hypotheca, larger rhombic-shaped intercalary plates, and an asymmetrical hypotheca. The genus Luciella is assigned to the order Peridiniales and the family Pfiesteriaceae based on plate tabulation, plate pattern, general morphology, and phylogenetic analysis. [source]


Molecular phylogenetic analysis of Leibnitzia Cass. (Asteraceae: Mutisieae: Gerbera -complex), an Asian,North American disjunct genus

JOURNAL OF SYSTEMATICS EVOLUTION, Issue 3 2010
Kristen E. BAIRD
Abstract Leibnitzia comprises six species of perennial herbs that are adapted to high elevation conditions and is one of only two Asteraceae genera known to have an exclusively disjunct distribution spanning central to eastern Asia and North America. Molecular phylogenetic analysis of Leibnitzia and other Gerbera -complex members indicates that Leibnitzia is monophyletic, which is in contrast with our expectation that the American Leibnitzia species L. lyrata and L. occimadrensis would be more closely related to another American member of the Gerbera -complex, namely Chaptalia. Ancestral area reconstructions show that the historical biogeography of the Gerbera -complex mirrors that of the entire Asteraceae, with early diverging lineages located in South America that were followed by transfers to Africa and Eurasia and, most recently, to North America. Intercontinental transfer of Leibnitzia appears to have been directed from Asia to North America. Independent calibrations of nuclear (ribosomal DNA internal transcribed spacer region) and chloroplast (trnL,rpl32 intron) DNA sequence data using relaxed clock methods and either mean rate or fossil-based priors unanimously support Miocene and younger divergence times for Gerbera -complex taxa. The ages are not consistent with most Gondwanan vicariance episodes and, thus, the global distribution of Gerbera -complex members must be explained in large part by long-distance dispersal. American species of Leibnitzia are estimated to have diverged from their Asian ancestor during the Quaternary (ca. 2 mya) and either migrated overland to North America via Beringia and retreated southwards along high elevation corridors to their present location in southwestern North America or were dispersed long distance. [source]


Large parts of the world are brown or black: A different view on the ,Green World'hypothesis

JOURNAL OF VEGETATION SCIENCE, Issue 3 2005
William J. Bond
Abstract. Climate sets the limits to plant growth but does climate determine the global distribution of major biomes? I suggest methods for evaluating whether vegetation is largely climate or consumer-controlled, focusing on large mammal herbivores and fire as influential consumers. Large parts of the world appear not to be at equilibrium with climate. Consumer-controlled ecosystems are ancient and diverse. Their distinctive ecology warrants special attention. [source]


Searching for the source regions of martian meteorites using MGS TES: Integrating martian meteorites into the global distribution of igneous materials on Mars

METEORITICS & PLANETARY SCIENCE, Issue 6 2003
Victoria E. HAMILTON
We deconvolved the TES data set using laboratory spectra of 6 martian meteorites (Los Angeles, Zagami, ALH A77005, Nakhla, ALH 84001, and Chassigny) as end members, along with atmospheric and surface spectra previously derived from TES data. Global maps (16 pixels/degree) of the distribution of each meteorite end member show that meteorite-like compositions are not present at or above TES detectability limits over most of the planet's dust-free regions. However, we have confidently identified local-scale (100s-1000s km2) concentrations of olivine- and orthopyroxene-bearing materials similar to ALH A77005, Chassigny, and ALH 84001 in Nili Fossae, in and near Ganges Chasma, in the Argyre and Hellas basin rims, and in Eos Chasma. Nakhla-like materials are identified near the detection limit throughout the eastern Valles Marineris region and portions of Syrtis Major. Basaltic shergottites were not detected in any spatially coherent areas at the scale of this study. Martian meteorite-like lithologies represent only a minor portion of the dust-free surface and, thus, are not representative of the bulk composition of the ancient crust. Meteorite-like spectral signatures identified above TES detectability limits in more spatially restricted areas ([source]


Mitochondrial DNA reveals multiple Northern Hemisphere introductions of Caprella mutica (Crustacea, Amphipoda)

MOLECULAR ECOLOGY, Issue 5 2008
GAIL V. ASHTON
Abstract Caprella mutica (Crustacea, Amphipoda) has been widely introduced to non-native regions in the last 40 years. Its native habitat is sub-boreal northeast Asia, but in the Northern Hemisphere, it is now found on both coasts of North America, and North Atlantic coastlines of Europe. Direct sequencing of mitochondrial DNA (cytochrome c oxidase subunit I gene) was used to compare genetic variation in native and non-native populations of C. mutica. These data were used to investigate the invasion history of C. mutica and to test potential source populations in Japan. High diversity (31 haplotypes from 49 individuals), but no phylogeographical structure, was identified in four populations in the putative native range. In contrast, non-native populations showed reduced genetic diversity (7 haplotypes from 249 individuals) and informative phylogeographical structure. Grouping of C. mutica populations into native, east Pacific, and Atlantic groups explained the most among-region variation (59%). This indicates independent introduction pathways for C. mutica to the Pacific and Atlantic coasts of North America. Two dominant haplotypes were identified in eastern and western Atlantic coastal populations, indicating several dispersal routes within the Atlantic. The analysis indicated that several introductions from multiple sources were likely to be responsible for the observed global distribution of C. mutica, but the pathways were least well defined among the Atlantic populations. The four sampled populations of C. mutica in Japan could not be identified as the direct source of the non-native populations examined in this study. The high diversity within the Japan populations indicates that the native range needs to be assessed at a far greater scale, both within and among populations, to accurately assess the source of the global spread of C. mutica. [source]


Bipolar gene flow in deep-sea benthic foraminifera

MOLECULAR ECOLOGY, Issue 19 2007
J. PAWLOWSKI
Abstract Despite its often featureless appearance, the deep-ocean floor includes some of the most diverse habitats on Earth. However, the accurate assessment of global deep-sea diversity is impeded by a paucity of data on the geographical ranges of bottom-dwelling species, particularly at the genetic level. Here, we present molecular evidence for exceptionally wide distribution of benthic foraminifera, which constitute the major part of deep-sea meiofauna. Our analyses of nuclear ribosomal RNA genes revealed high genetic similarity between Arctic and Antarctic populations of three common deep-sea foraminiferal species (Epistominella exigua, Cibicides wuellerstorfi and Oridorsalis umbonatus), separated by distances of up to 17 000 km. Our results contrast with the substantial level of cryptic diversity usually revealed by molecular studies, of shallow-water benthic and planktonic marine organisms. The very broad ranges of the deep-sea foraminifera that we examined support the hypothesis of global distribution of small eukaryotes and suggest that deep-sea biodiversity may be more modest at global scales than present estimates suggest. [source]


Isolation and characterization of microsatellite loci in Bemisia tabaci

MOLECULAR ECOLOGY RESOURCES, Issue 1 2003
P. J. De Barro
Abstract Bemisia tabaci (Hemiptera: Aleyrodidae) is a haplo-diploid species with a global distribution demonstrating strong geographical structure with eight recognizable genetic groups. Fifteen microsatellite loci (335 alleles, 6,44 alleles per locus) were derived from four of the eight groups and were then screened across 33 populations. These loci clearly differentiate the populations. The microsatellites amplified best in individuals from genetic groups rep-resenting the Mediterranean, Middle East, Asia (three groups) and Australasia/Oceania and amplified less well with populations from sub-Saharan Africa and the New World. This differential amplification pattern is a direct result of the relatedness to the microsatellite source material. [source]


Composition, geographical affinities and endemism of the Iberian Peninsula orchid flora

NORDIC JOURNAL OF BOTANY, Issue 3-4 2007
Sonia Bernardos
The orchid flora of the Iberian Peninsula is relatively well known, but its biogeographical and diversity patterns have until now remained unanalysed. This work compares the richness of this flora with that of 27 other territories in different continents and at different latitudes, with the aim of establishing whether it is richer or poorer than might be expected. Latitude was found to be an excellent predictor of regional orchid species richness. With 122 taxa, the orchid flora of the Iberian Peninsula is more or less as diverse as that of other Mediterranean areas of similar latitude (e.g. France, Greece or Italy), but more diverse than other European or indeed North African orchid floras. In this study, the Iberian orchid species were assigned to eight monophyletic clades and the global distribution of these are mapped to establish continental affinities between the floras. A recent floristic account on the Iberian orchids was also used to assign the orchid taxa to habitats, and the relationship between the number of endemisms and their habitats was analysed. The patterns of endemism differed in different habitats. Very high levels of endemism were found in habitats peculiar to the Mediterranean Basin, indicating the relict status of its orchid flora. [source]


Measurement and analysis of truck and rail shipping environment in India

PACKAGING TECHNOLOGY AND SCIENCE, Issue 6 2007
S. P. Singh
Abstract Free trade agreements have been on the rise in all regions of the world in the past decade. This has allowed for global distribution and marketing of products in an international market. Products once produced for domestic markets must now be able to compete in international markets without trade barriers. Increased international commerce and manufacturing have forced many packaging and logistics engineers to broaden their true understanding of the global distribution environment. India is a recent entrant on the global arena for manufacturing and services. While China's economic developments have dominated global headlines, India's own growth has been impressive as well, with a gross domestic product rising 5% per annum on average since 1990. India is hence primed to follow China as the next low-cost manufacturing super power. With an increasing interest from multinational corporations in conducting commerce with India, there arises a great need to understand the conditions of the transportation infrastructure there to promote logistical understanding of the distribution environments. This paper provides a brief overview of the road and rail transportation environment in India. It also provides the results of a 2 year study that measured and analysed truck and rail transport vibration for the major freight distribution routes between New Delhi, Bangalore, Mumbai, Chennai, Hyderabad and Kolkatta. Copyright 2007 John Wiley & Sons, Ltd. [source]


Recent advances in the biogeography and genecology of symbiotic Frankia and its host plants

PHYSIOLOGIA PLANTARUM, Issue 3 2007
David R. Benson
Molecular phylogenetic approaches have begun to outline the origin, distribution and diversity of actinorhizal partners. Geographic isolation of Frankia and its host plants resulting from shifting continents and dispersal patterns have apparently led to the development of Frankia genotypes with differing affinities for host genera, even within the same plant family. Actinorhizal plant genera of widespread global distribution tend to nodulate readily even outside their native ranges. These taxa may maintain infective Frankia populations of considerable diversity on a broad scale. Arid environments seem to have distinctive actinorhizal partnerships, with smaller and more specific sets of Frankia symbionts. This has led to the hypothesis that some host families have taxa that are evolving towards narrow strain specificity, perhaps because of drier habitats where fewer Frankia strains would be able to survive. Harsh conditions such as water-saturated soils near lakes, swamps or bogs that are typically acidic and low in oxygen may similarly lessen the diversity of Frankia strains present in the soil, perhaps limiting the pool of frankiae available for infection locally and, at a larger scale, for natural selection of symbiotic partnerships with host plants. Recent molecular ecological studies have also provided examples of Frankia strain sorting by soil environment within higher order cluster groupings of Frankia host specificity. Future frontiers for ecological research on Frankia and actinorhizal plants include the soil ecosystem and the genome of Frankia and its hosts. [source]


HUMEAN SUPERVENIENCE AND PERSONAL IDENTITY

THE PHILOSOPHICAL QUARTERLY, Issue 221 2005
Ryan Wasserman
Humeans hold that the nomological features of our world, including causal facts, are determined by the global distribution of fundamental properties. Since persistence presupposes causation, it follows that facts about personal identity are also globally determined. I argue that this is unacceptable for a number of reasons, and that the doctrine of Humean supervenience should therefore be rejected. [source]


Recent developments in gravity-wave effects in climate models and the global distribution of gravity-wave momentum flux from observations and models

THE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 650 2010
M. J. Alexander
Abstract Recent observational and theoretical studies of the global properties of small-scale atmospheric gravity waves have highlighted the global effects of these waves on the circulation from the surface to the middle atmosphere. The effects of gravity waves on the large-scale circulation have long been treated via parametrizations in both climate and weather-forecasting applications. In these parametrizations, key parameters describe the global distributions of gravity-wave momentum flux, wavelengths and frequencies. Until recently, global observations could not define the required parameters because the waves are small in scale and intermittent in occurrence. Recent satellite and other global datasets with improved resolution, along with innovative analysis methods, are now providing constraints for the parametrizations that can improve the treatment of these waves in climate-prediction models. Research using very-high-resolution global models has also recently demonstrated the capability to resolve gravity waves and their circulation effects, and when tested against observations these models show some very realistic properties. Here we review recent studies on gravity-wave effects in stratosphere-resolving climate models, recent observations and analysis methods that reveal global patterns in gravity-wave momentum fluxes and results of very-high-resolution model studies, and we outline some future research requirements to improve the treatment of these waves in climate simulations. Copyright 2010 Royal Meteorological Society and Crown in the right of Canada [source]


Genetic tracking of basking shark products in international trade

ANIMAL CONSERVATION, Issue 2 2007
J. E. Magnussen
Abstract Mounting evidence that sharks are being over-fished to supply shark fin markets is causing widespread concern about the sustainability of these practices. The basking shark Cetorhinus maximus, whose fins command high market prices, has proven especially sensitive to exploitation. To prevent further population declines, this species is now protected in the territorial waters of several countries, and is listed on Appendix II of the Convention on International Trade in Endangered Species (CITES) requiring monitoring of trade in its products by all parties to CITES. Tracking trade in basking shark products, however, is often hampered by difficulties in identifying shark products to species of origin. Here, we present the development and application of a streamlined genetic forensics assay that does not require DNA sequencing to identify basking shark products. The dual-primer, species-specific polymerase chain reaction strategy provides diagnostic redundancy for robustness in legal venues. It is also effective for identifying basking shark products regardless of geographic origin, an important consideration, given the global distribution of the species and international sourcing of fins to the trade. Application of the assay confirmed the presence of basking shark fins in the Hong Kong and Japan markets, and indicated an apparent relationship between the Chinese fin trader category ,Nuo Wei Tian Jiu' and fins from basking sharks. The assay was also used in a law enforcement investigation to document illegal trade in basking shark fins in the United States where this species is prohibited from harvest and trade. These trade detections suggest that the high market value of basking shark fins is continuing to drive the exploitation, surreptitious and otherwise, of this highly threatened species, underscoring the need for improved trade monitoring. The streamlined assay developed here can assist in monitoring and conservation on a worldwide scale. [source]


Anthropology in the financial crisis

ANTHROPOLOGY TODAY, Issue 6 2008
Keith Hart
This editorial considers the opportunities opened up for anthropologists by the financial crisis of 2008. The chief of these is the exposure of cracks in the intellectual hegemony of free-market economics which contributed to an unnecessarily defensive posture on the part of most anthropologists during the period of neoliberal globalization. The authors claim that anthropology can bridge the gap between everyday life and the world at large by combining the study of ideas and social actions. We draw on Ortiz's research among financial professionals to show how working practices informed by economic liberalism can have extremely unequal consequences for the global distribution of resources. The perspectives of Mauss and Polanyi on political economy can help us to make sense of the current situation and to recommend a path forward beyond market fundamentalism. Their general ideas lend power to the concrete findings of field research. The mask of neoliberal ideology has been ripped from the politics of world economy. Anthropology's highest mission is to start from where people are and go with them wherever they take you. What better time to follow this imperative than when the model the world has been compelled to live by for three decades is in such disarray? [source]


A robust method to determine global distribution of atmospheric boundary layer top from COSMIC GPS RO measurements

ATMOSPHERIC SCIENCE LETTERS, Issue 3 2010
M. V. Ratnam
Abstract In this study, we introduce a robust method for precise determination of atmospheric boundary layer (ABL) top from COSMIC global positioning system radio occultation measurements. We apply a wavelet covariance transform to compute the convolution of COSMIC-observed bending angle/refractivity profile with a Haar function and use the maximum covariance to identify the ABL top, making detection of even small transitions possible. Results obtained were compared with radiosonde N profiles for verification of the ABL top. This procedure developed was used to study the global distribution of ABL top with special reference to the inter-tropical convergence zone. Copyright 2010 Royal Meteorological Society [source]


The origin and early evolution of dinosaurs

BIOLOGICAL REVIEWS, Issue 1 2010
Max C. Langer
The oldest unequivocal records of Dinosauria were unearthed from Late Triassic rocks (approximately 230 Ma) accumulated over extensional rift basins in southwestern Pangea. The better known of these are Herrerasaurus ischigualastensis, Pisanosaurus mertii, Eoraptor lunensis, and Panphagia protos from the Ischigualasto Formation, Argentina, and Staurikosaurus pricei and Saturnalia tupiniquim from the Santa Maria Formation, Brazil. No uncontroversial dinosaur body fossils are known from older strata, but the Middle Triassic origin of the lineage may be inferred from both the footprint record and its sister-group relation to Ladinian basal dinosauromorphs. These include the typical Marasuchus lilloensis, more basal forms such as Lagerpeton and Dromomeron, as well as silesaurids: a possibly monophyletic group composed of Mid-Late Triassic forms that may represent immediate sister taxa to dinosaurs. The first phylogenetic definition to fit the current understanding of Dinosauria as a node-based taxon solely composed of mutually exclusive Saurischia and Ornithischia was given as "all descendants of the most recent common ancestor of birds and Triceratops". Recent cladistic analyses of early dinosaurs agree that Pisanosaurus mertii is a basal ornithischian; that Herrerasaurus ischigualastensis and Staurikosaurus pricei belong in a monophyletic Herrerasauridae; that herrerasaurids, Eoraptor lunensis, and Guaibasaurus candelariensis are saurischians; that Saurischia includes two main groups, Sauropodomorpha and Theropoda; and that Saturnalia tupiniquim is a basal member of the sauropodomorph lineage. On the contrary, several aspects of basal dinosaur phylogeny remain controversial, including the position of herrerasaurids, E. lunensis, and G. candelariensis as basal theropods or basal saurischians, and the affinity and/or validity of more fragmentary taxa such as Agnosphitys cromhallensis, Alwalkeria maleriensis, Chindesaurus bryansmalli, Saltopus elginensis, and Spondylosoma absconditum. The identification of dinosaur apomorphies is jeopardized by the incompleteness of skeletal remains attributed to most basal dinosauromorphs, the skulls and forelimbs of which are particularly poorly known. Nonetheless, Dinosauria can be diagnosed by a suite of derived traits, most of which are related to the anatomy of the pelvic girdle and limb. Some of these are connected to the acquisition of a fully erect bipedal gait, which has been traditionally suggested to represent a key adaptation that allowed, or even promoted, dinosaur radiation during Late Triassic times. Yet, contrary to the classical "competitive" models, dinosaurs did not gradually replace other terrestrial tetrapods over the Late Triassic. In fact, the radiation of the group comprises at least three landmark moments, separated by controversial (Carnian-Norian, Triassic-Jurassic) extinction events. These are mainly characterized by early diversification in Carnian times, a Norian increase in diversity and (especially) abundance, and the occupation of new niches from the Early Jurassic onwards. Dinosaurs arose from fully bipedal ancestors, the diet of which may have been carnivorous or omnivorous. Whereas the oldest dinosaurs were geographically restricted to south Pangea, including rare ornithischians and more abundant basal members of the saurischian lineage, the group achieved a nearly global distribution by the latest Triassic, especially with the radiation of saurischian groups such as "prosauropods" and coelophysoids. [source]


Investigation of air gaps entrapped in protective clothing systems

FIRE AND MATERIALS, Issue 3 2002
Young Kim Il
Air gaps entrapped in protective clothing are known as one of the major factors affecting heat transfer through multiple layers of flexible clothing fabrics. The identification and quantification of the air gaps are two aspects of a multidisciplinary research effort directed toward improving the flame/thermal protective performance of the clothing. Today's three-dimensional (3-D) whole body digitizers, which provide accurate representations of the surface of the human body, can be a novel means for visualizing and quantifying the air gaps between the wearer and his clothing. In this paper we discuss how images from a 3-D whole body digitizer are used to determine local and global distributions of air gaps and the quantification of air gap sizes in single and multilayer clothing systems dressed on a thermal manikin. Examples are given that show concordance between air gap distributions and burn patterns obtained from full-scale manikin fire tests. We finish with a discussion of the application of air gap information to bench-scale testing to improve the protective performance of current flame/thermal protective clothing. Copyright 2002 John Wiley & Sons, Ltd. [source]


Recent developments in gravity-wave effects in climate models and the global distribution of gravity-wave momentum flux from observations and models

THE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 650 2010
M. J. Alexander
Abstract Recent observational and theoretical studies of the global properties of small-scale atmospheric gravity waves have highlighted the global effects of these waves on the circulation from the surface to the middle atmosphere. The effects of gravity waves on the large-scale circulation have long been treated via parametrizations in both climate and weather-forecasting applications. In these parametrizations, key parameters describe the global distributions of gravity-wave momentum flux, wavelengths and frequencies. Until recently, global observations could not define the required parameters because the waves are small in scale and intermittent in occurrence. Recent satellite and other global datasets with improved resolution, along with innovative analysis methods, are now providing constraints for the parametrizations that can improve the treatment of these waves in climate-prediction models. Research using very-high-resolution global models has also recently demonstrated the capability to resolve gravity waves and their circulation effects, and when tested against observations these models show some very realistic properties. Here we review recent studies on gravity-wave effects in stratosphere-resolving climate models, recent observations and analysis methods that reveal global patterns in gravity-wave momentum fluxes and results of very-high-resolution model studies, and we outline some future research requirements to improve the treatment of these waves in climate simulations. Copyright 2010 Royal Meteorological Society and Crown in the right of Canada [source]