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The Edge (the + edge)
Kinds of The Edge Selected AbstractsRussia's Northern Regions on the Edge: Communities, Industries and Populations from Murmansk to Magadan , Edited by Vesa Rautio and Markku TykkylainenGEOGRAPHICAL RESEARCH, Issue 3 2010John Holmes No abstract is available for this article. [source] On the Edge of the Law: Women's Property Rights and Dispute Resolution in Kisii, KenyaLAW & SOCIETY REVIEW, Issue 1 2009Elin Henrysson Scholars have argued that economic efficiency requires a clear definition of the rights of ownership, contract, and transfer of land. Ambiguity in the definition or enforcement of any of these rights leads to an increase in transaction costs in the exchange and transfer of land as well as a residual uncertainty after any land contract. In Kenya, government efforts at establishing clearly defined property rights and adjudication mechanisms have been plagued by the existence of alternative processes for the adjudication of disputes. Customary dispute resolution has been praised as an inexpensive alternative to official judicial processes in a legally pluralistic environment. However, our research demonstrates that customary processes may also carry a monetary cost that puts them beyond the means of many citizens. This article compares the costs and processes of the formal and informal methods of property rights adjudication for women in the Kisii region of Kenya. The research results suggest that women have weak property rights overall, they have limited access to formal dispute resolution systems because of costs involved, and even the informal systems of conflict resolution are beyond the means of many citizens. [source] Work on the Edge: Enterprise and Employment between City and CountrysideANTHROPOLOGY OF WORK REVIEW, Issue 3-4 2002Robyn Eversole An interest in the microenterprise finance movement's proposals to increase income and employment in poor local economies led to this study of a Latin American barrio marginal in miniature. The article explores the main income-generating activities of Upper Barrio Japón residents and their adult children, and their use of the plentiful microenterprise finance services on offer in the city of Sucre, Bolivia. The article concludes that microenterprise, often at very small scale, is an important economic strategy for many local residents, but that casual labour and long-distance migration is often more important for young people. Local microenterprises cross urban, suburban and rural markets, but tend to focus on small scale activity: rustic production and retail commerce. Children study, but are entering a very circumscribed range of occupations, with little representation in the professions or skilled trades. Finally, local people use microenterprise finance services, but only sparingly; the ingredients for economic transformation would appear to be elsewhere. [source] Making The Cut: A Surgeon's Stories of Life on the EdgeANZ JOURNAL OF SURGERY, Issue 3 2010B. Sc, Eric Levi MBBS, PGDipSurgAnat No abstract is available for this article. [source] Style of Knowing Regarding UncertaintiesCURRICULUM INQUIRY, Issue 1 2007DEBORAH HELSING This article addresses a key contrast in how teachers may regard the uncertainties of their work, considering how an orientation to uncertainty can be regarded as a decision-making style. Through the use of case studies, the author contrasts two teachers. One is oriented toward uncertainties in her work and describes her herself as being always "on the edge" of her capabilities, constantly seeking out perspectives that differ from and challenge her own and remaining vigilant to the need for improvising to respond to the circumstances of the moment. The other is oriented away from uncertainties and describes herself as prepared and deliberate; committed to achieving outcomes in line with her articulated goals and purposes; and purposeful about which unresolved questions she chooses to pursue. This contrast has implications not only for how these teachers make decisions and view their professional growth, but also for how some teachers may be understood, and misunderstood, by others. In a culture that often seeks to ignore pervasive moral ambiguities and focuses instead on questions for which there are easily identifiable answers (Cuban, 1992), an orientation toward uncertainty is more likely to be devalued or seen as an indication that one is not teaching well. Identifying these different approaches to decision-making styles enables us to appreciate the integrity and strength of each, as well as the limitations of each, suggesting new possibilities for research and for teachers' professional development. [source] In vivo determination of muscle viscoelasticity in the human legACTA PHYSIOLOGICA, Issue 4 2001S. Fukashiro The purpose of this study was to examine the methodological validity of the free vibration technique for determining individual viscoelastic characteristics of the human triceps surae muscle-tendon complex (MTC) in vivo. Six subjects sat with first phalangeal joint of the forefoot on the edge of a force-plate. The special frame on the knee was loaded with weight (0,40 kg) for testing. Oscillations of the triceps surae MTC system were initiated with a hand-held hammer by tapping the weight. In order to keep the same posture, the output of the force plate was displayed on the oscilloscope and subjects were asked to maintain the beam on the oscilloscope at a particular location in relation to a reference line. The damped oscillations in conjunction with the equation of motion of a damped mass-spring model were used to calculate the viscosity of muscle (b) and the elasticity of muscle fibres and tendon (k) in each subject, considering moment arm of the ankle joint. With this arrangement, we have obtained high reproducibility in this method. The coefficient of variations (CVs) of b and k in five trials at each weight were quite small (range: 0.5,18.7% in b and 1.0,15.1% in k). There were no significant differences in viscoelastic coefficients between right and left legs. Therefore, it appears that free vibration technique, used here, is adequate in describing the viscoelastic characteristics of the triceps surae in vivo in humans. [source] Genetic diversity of endangered brown bear (Ursus arctos) populations at the crossroads of Europe, Asia and AfricaDIVERSITY AND DISTRIBUTIONS, Issue 5 2009Sébastien Calvignac Abstract Aim, Middle East brown bears (Ursus arctos syriacus Hemprich and Ehrenberg, 1828) are presently on the edge of extinction. However, little is known of their genetic diversity. This study investigates that question as well as that of Middle East brown bear relationships to surrounding populations of the species. Location, Middle East region of south-western Asia. Methods, We performed DNA analyses on 27 brown bear individuals. Twenty ancient bone samples (Late Pleistocene to 20th century) from natural populations and seven present-day samples obtained from captive individuals were analysed. Results, Phylogenetic analyses of the mitochondrial sequences obtained from seven ancient specimens identify three distinct maternal clades, all unrelated to one recently described from North Africa. Brown bears from Iran exhibit striking diversity (three individuals, three haplotypes) and form a unique clade that cannot be linked to any extant one. Individuals from Syria belong to the Holarctic clade now observed in Eastern Europe, Turkey, Japan and North America. Specimens from Lebanon surprisingly appear as tightly linked to the clade of brown bears now in Western Europe. Moreover, we show that U. a. syriacus in captivity still harbour haplotypes closely linked to those found in ancient individuals. Main conclusion, This study brings important new information on the genetic diversity of brown bear populations at the crossroads of Europe, Asia and Africa. It reveals a high level of diversity in Middle East brown bears and extends the historical distribution of the Western European clade to the East. Our analyses also suggest the value of a specific breeding programme for captive populations. [source] Divergent evolution in fluviokarst landscapes of central KentuckyEARTH SURFACE PROCESSES AND LANDFORMS, Issue 7 2004Jonathan D. Phillips Abstract Central Kentucky is characterized by a mixture of karst and ,uvial features, typically manifested as mosaic of karst-rich/channel-poor (KRCP) and channel-rich/karst-poor (CRKP) environments. At the regional scale the location and distribution of KRCP and CRKP areas are not always systematically related to structural, lithological, topographic, or other controls. This study examines the relationship of KRCP and CRKP zones along the Kentucky River gorge area, where rapid incision in the last 1·5 million years has lowered local base levels and modi,ed slopes on the edge of the inner bluegrass plateau. At the scale of detailed ,eld mapping on foot within a 4 km2 area, the development of karst and ,uvial features is controlled by highly localized structural and topographic constraints, and can be related to slope changes associated with retreat of the Kentucky River gorge escarpment. A conceptual model of karst/,uvial transitions is presented, which suggests that minor, localized variations are suf,cient to trigger a karst,,uvial or ,uvial,karst switch when critical slope thresholds are crossed. Copyright © 2004 John Wiley & Sons, Ltd. [source] Gully-head erosion processes on a semi-arid valley floor in Kenya: a case study into temporal variation and sediment budgetingEARTH SURFACE PROCESSES AND LANDFORMS, Issue 9 2001D. J. Oostwoud Wijdenes Abstract A three year monitoring programme of gully-head retreat was established to assess the significance of sediment production in a drainage network that expanded rapidly by gully-head erosion on the low-angled alluvio-lacustrine Njemps Flats in semi-arid Baringo District, Kenya. This paper discusses the factors controlling the large observed spatial and temporal variation in gully-head retreat rates, ranging from 0 to 15 m a,1. The selected gullies differed in planform and in runoff-contributing catchment area but soil material and land use were similar. The data were analysed at event and annual timescales. The results show that at annual timescale rainfall amount appears to be a good indicator of gully-head retreat, while at storm-event timescale rainfall distribution has to be taken into account. A model is proposed, including only rainfall (P) and the number of dry days (DD) between storms: which explains 56 per cent of the variation in retreat rate of the single-headed gully of Lam1. A detailed sediment budget has been established for Lam1 and its runoff-contributing area (RCA). By measuring sediment input from the RCA, the sediment output by channelized flow and linear retreat of the gully head for nine storms, it can be seen that erosion shifts between different components of the budget depending on the duration of the dry period (DD) between storms. Sediment input from the RCA was usually the largest component for the smaller storms. The erosion of the gully head occurred as a direct effect of runoff falling over the edge (GHwaterfall) and of the indirect destabilization of the adjacent walls by the waterfall erosion and by saturation (GHmass/storage). The latter component (GHmass/storage) was usually much larger that the former (GHwaterfall). The sediment output from the gully was strongly related to the runoff volume while the linear retreat, because of its complex behaviour, was not. Overall, the results show that the annual retreat is the optimal timescale to predict retreat patterns. More detailed knowledge about relevant processes and interactions is necessary if gully-head erosion is to be included in event-based soil erosion models. Copyright © 2001 John Wiley & Sons, Ltd. [source] Patterns of commonness and rarity in central European birds: reliability of the core-satellite hypothesis within a large scaleECOGRAPHY, Issue 4 2002David Storch The frequency distribution of species' area of occupancy is often bimodal, most species being either very rare or very common in terms of number of occupied sites. This pattern has been attributed to the nonlinearity associated with metapopulation dynamics of the species, but there are also other explanations comprising sampling artifact and frequency distribution of suitable habitats. We tested whether the bimodal frequency distribution of occupied squares in central European birds could be derived solely from the frequency distribution of species population sizes (i.e. the sampling artifact hypothesis) or from the spatial distribution of their preferred habitats. Both models predict high proportion of very common species, i.e. the right side of frequency distribution. Bimodality itself is well predicted by models based on random placement of individuals according to their abundances but neither model predicts the observed prevalence of rare species. Even the combined models that assume random placement of individuals within the squares with suitable habitat do not predict such a high proportion of rare species. The observed distribution is more aggregated, rare species occupying a smaller portion of suitable habitat than predicted on the basis of their abundance. The pattern is consistent with metapopulation processes involving local population extinctions. The involvement of these processes is supported by two further observations. First, species rarity is associated with significant population trend and/or location on the edge of their ranges within central Europe, both situations presumably associated with metapopulation processes. Second, suitable habitats seem to be either saturated or almost unoccupied, which is consistent with the predictions of the metapopulation model based on nonlinear dynamics of extinction and colonization. Although the habitat suitability is an important determinant of species distribution, the rarity of many species of birds within this scale of observation seems to be affected by other factors, including local population extinctions associated with fragmentation of species' habitats. [source] Seed weevils living on the edge: pressures and conflicts over body size in the endoparasitic Curculio larvaeECOLOGICAL ENTOMOLOGY, Issue 3 2009RAÚL BONAL Abstract 1.,Body size in parasitic insects can be subjected to contrasting selective pressures, especially if they complete their development within a single host. On the one hand, a larger body size is associated with a higher fitness. On the other hand, the host offers a discrete amount of resources, thus constraining the evolution of a disproportionate body size. 2.,The present study used the weevil Curculio elephas as a study model. Larvae develop within a single acorn, feeding on its cotyledons, and larval body size is strongly related to individual fitness. 3.,The relationship between larval and acorn size was negatively exponential. Larval growth was constrained in small acorns, which did not provide enough food for the weevils to attain their potential size. Larval size increased and levelled off in acorns over a certain size (inflexion point), in which cotyledons were rarely depleted. When there were more than one larva per acorn, a larger acorn was necessary to avoid food depletion. 4.,The results show that C. elephas larvae are sometimes endoparasitic, living on the edge of host holding capacity. If they were smaller they could avoid food depletion more easily, but the fitness benefits linked to a larger size have probably promoted body size increase. The strong negative effects of conspecific competition may have possibly influenced female strategy of laying a single egg per seed. 5.,Being larger and fitter, but always within the limits of the available host sizes, may be one main evolutionary dilemma in endoparasites. [source] Threatened obligatory riverine fishes in human-modified Polish riversECOLOGY OF FRESHWATER FISH, Issue 1-2 2000T. Penczak Abstract , The fate of obligatory riverine fish species (rheophils), which are the objects of anglers' exploitation (chub ,Leuciscus cephalus, nase ,Chondrostoma nasus, barbel ,Barbus barbus, gudgeon ,Gobio gobio), and brown trout (Salmo trutta m. fario) and grayling (Thymallus thymallus) (in the Gwda River basin only), were investigated in large alluvial rivers (Pilica and Warta) and in the medium-sized Gwda River basin. The Pilica (1973) and the Warta (1986,1987) were divided by large dams without fish ladders in their middle courses. The Gwda River was divided by only a few dams along its course, but its tributaries carrying pure water had numerous small dams that supplied water for fish farms. Other stresses influencing fish populations in these rivers were: pollution, overfishing, hydroelectric plants and bank revetments. Because the listed stresses occurred alternately and at various periods of time in these rivers, this enabled attributing the cause for extinction and reduction of the abundance and distribution. In the salmon Gwda River basin, a drastic decrease in spatial distribution and reduction of occurrence ranges of brown trout, grayling and barbel was evident in respect to the first study period (1980s) in the 1990s. In the large, alluvial Pilica River, nase, barbel and dace are on the edge of extinction and chub and gudgeon are vulnerable. In the Warta's tailwater, barbel is an extinct species, and chub, dace and gudgeon are vulnerable ones. In a site in the backwater, none of the above mentioned species became extinct, but their abundance and occurrence frequency decreased a bit in respect to the pre-impoundment period. Roach-generalist, which was used in this research as a "control" species, increased in abundance in all 3 rivers. These investigations univocally proved that the dams cause catastrophic stress for obligatory riverine species., [source] PLASTICITY IN QUEEN NUMBER AND SOCIAL STRUCTURE IN THE INVASIVE ARGENTINE ANT (LINEPITHEMA HUMILE)EVOLUTION, Issue 10 2002Krista K. Ingram Abstract., In many polygynous social insect societies, ecological factors such as habitat saturation promote high queen numbers by increasing the cost of solitary breeding. If polygyny is associated with constrained environments, queen number in colonies of invasive social insects should increase as saturation of their new habitat increases. Here I describe the variation in queen number, nestmate relatedness, and nest size along a gradient of time since colonization in an invading population of Argentine ants (Linepithema humile) in Haleakala, Hawaii. Nest densities in this population increase with distance from the leading edge of the invasion, reaching a stable density plateau approximately 80 m from the edge (> 2 years after colonization). Although the number of queens per nest in Haleakala is generally lower than previously reported for Argentine ants, there is significant variation in queen number across this population. Both the observed and effective queen numbers increase across the density gradient, and nests in the center of the population contain queen numbers three to nine times higher than those on the edge of the invasion. The number of workers per nest is correlated with queen number, and nests in the center are six times larger than nests at the edge. Microsatellite analysis of relatedness among nestmates reveals that all nests in the Haleakala population are characterized by low relatedness and have evidence of multiple reproducing queens. Relatedness values are significantly lower in nests in the center of the population, indicating that the number of reproducing queens is greater in areas of high nest density. The variation in queen number and nestmate relatedness in this study is consistent with expectations based on changes in ecological constraints during the invasion of a new habitat, suggesting that the social structure of Argentine ant populations is strongly influenced by ecological factors. Flexibility in social structure may facilitate persistence in variable environments and may also confer significant advantages to a species when introduced into new areas. [source] Climate for Scandal: Corporate Environments that Contribute to Accounting FraudFINANCIAL REVIEW, Issue 1 2007Claire E. Crutchley G34; G38; K22 Abstract We examine the governance characteristics, earnings quality, growth rates, dividend policy, and compensation structure of 97 firms recently under investigation by the Securities and Exchange Commission (SEC) for accounting fraud. Our results show that the corporate environment most likely to lead to an accounting scandal manifests significant growth and accounting practices that are already pushing the envelope of earnings smoothing. Firms operating in this environment seem more likely to tip over the edge into fraud if there are fewer outsiders on the audit committee and outside directors appear overcommitted. [source] Characterizing anthropic sediments in north European Neolithic settlements: An assessment from Skara Brae, OrkneyGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 3 2006Ian A. Simpson The creation of anthropic sediments, traditionally referred to under the blanket term midden, through the utilization of settlement waste materials in domestic settlement construction was first recognized during early excavations at the Orcadian Neolithic site of Skara Brae (V.G. Childe, 1931a; 1931b). Prior to the present study there has been no systematic attempt to identify the nature of these sediments at Skara Brae, whose likely occupation dates between ,3100 and 2500 B.C., or to assess whether different materials were incorporated into construction or varied with different phases of site formation. The opportunity to begin addressing these issues arose with the location of undisturbed sediment samples held in storage since the last site excavations of 1972,1973 (D.V. Clarke, 1976). Ten thin sections were manufactured from these samples, representing earlier and later phases of Neolithic settlement at Skara Brae. Observations using thin-section micromorphology, supported by total phosphorus and particle-size distribution analyses, suggest that both earlier and later settlement phases show accumulation of household waste dominated by fuel residues. These wastes may have been used to help stabilize wind-blown sand deposits during the later settlement phases. In addition, the use of clay material tempered with household waste is associated with wall construction. Animal manures are only evident in anthropic deposits on the edge of the main settlement site where composting may have been taking place, and there is no evidence for their use in site construction. The authors conclude by drawing attention to possible diverse uses of anthropic sediments in settlement construction at other Neolithic settlements in Orkney. © 2006 Wiley Periodicals, Inc. [source] ISLANDS AS NOVELTY SITES,GEOGRAPHICAL REVIEW, Issue 2 2007GODFREY BALDACCHINO ABSTRACT. Being on the edge, being out of sight and so out of mind, exposes the weakness of mainstream ideas, orthodoxies, and paradigms and foments alternatives to the status quo. Islands are thus propelled as sites of innovative conceptualizations, whether of nature or human enterprise, whether virtual or real. They stand out as sites of novelty; they tend toward clairvoyance; they are disposed to act as advance indicators or extreme reproductions of what is present or future elsewhere. This article, which is essentially bibliographical, celebrates islands as the quintessential sites for experimentation, with reference to the physical sciences, the social sciences, and literature. [source] On the relationship between global warming, local warming in the Netherlands and changes in circulation in the 20th centuryINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 14 2003Geert Jan van Oldenborgh Abstract The temperature in De Bilt in the Netherlands has risen by 1 K over the 20th century. This rise parallels the rise in global temperature quite closely, albeit with a slightly higher amplitude. A linear relationship between the two, with a regression coefficient close to one, is an obvious first-order approximation. This is supported by the spatial homogeneity of global warming during the 20th century, the lack of seasonality in the temperature rise, and the residuals being almost white in time. The wind direction is used as a proxy for circulation type. Locally measured wind direction gives the same results as geostrophic wind direction from pressure stations, so that systematic errors are not likely to be large. The temperature in the Netherlands, on the edge of the continent, strongly depends on the wind direction. For most wind directions and seasons the average temperature per wind direction has increased. The exception is northeasterly winds in winter, in which the variability is too large to observe a trend. The increased temperature for each wind direction can explain the observed temperature rise in all seasons within the 95% error estimates. Changes in the distribution of wind directions explain most of the interannual variability of temperature. On longer time scales, these changes have led to cooler weather in the middle of the century, but no trend is discernible over the whole century. However, in late winter and spring there is clear evidence for a change in the frequency distribution of circulation patterns affecting the Netherlands over the second half of the 20th century. During the months of February to April, more days with southwesterly wind and fewer with northeasterlies have increased the temperature even more than the observed increase in temperature per wind direction. Copyright © 2003 Royal Meteorological Society [source] Topography Mediated Patterning of Inorganic Materials by Spray Pyrolysis,ADVANCED MATERIALS, Issue 22 2006D. Beckel Microstructured ceramic thin films are produced by spray pyrolysis of metal salt solutions onto micromachined substrates. The ceramic structures built on the substrate result from preferential assembly of particles on the edge of the initially micromachined structures, leading to smaller lateral dimensions (1,2 ,m in width) than the initial structures on the substrate (see figure). The assembly process amplifies the height of the initial structures by a factor of approximately thirty, resulting in features with an aspect ratio of three. [source] Providing multimedia communications services from high altitude platformsINTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING, Issue 6 2001D. Grace Abstract System level design considerations for high altitude platforms operating in the mm-wave bands are examined. Propagation effects in these bands are outlined, followed by a brief introduction to different platform scenarios. Ground-based and platform-based fixed wireless access scenarios are considered, and it is shown that using a platform, a single base station can supply a much larger coverage area than a terrestrial base station. The effects on performance of platform displacement from its desired location with both fixed and steerable antennas are also examined. It is shown that steerable antennas are of most use when fixed stations are immediately below the platform, with no benefit for fixed stations on the edge of coverage. The bandwidths required to serve several traffic distributions (suburbs and city centre based) are evaluated using the Shannon equation. It is shown that capacity can be constrained when users are located in the city centres, despite longer line of sight paths to users out in the suburbs. The effects of temporal changes in the spatial traffic distribution are investigated. It is shown that bandwith requirements can be reduced if the platform moves to track these changes. Copyright © 2001 John Wiley & Sons, Ltd. [source] Application of siphon principle to fluid drainage in transurethral surgeryINTERNATIONAL JOURNAL OF UROLOGY, Issue 8 2006AKITO TERAI Abstract, Transurethral resection is usually performed using an all-in-one drape with a fluid collection pouch, drainage port and hose. Gravity drainage of irrigation fluid through the hose is often hampered, resulting in fluid retention in the pouch. We applied a siphon principle to facilitate fluid drainage by making a U-shaped bend near the distal end of the hose, using an adhesive tape, and hooking the distal end of inverted U shape on the edge of bucket placed on the floor. When the hose is filled with irrigation fluid up to the crest of the siphon, fluid flow driven by atmospheric pressure continues until the pouch is evacuated. Repriming and restarting occur automatically throughout the operation. This simple device has virtually eliminated fluid retention in the pouch and proved to be especially useful in transurethral prostatectomy, which requires a large amount of irrigation fluid. [source] Thriving while working on the edge: nurses leading change worldwideINTERNATIONAL NURSING REVIEW, Issue 4 2008Stephanie L. Ferguson PhD No abstract is available for this article. [source] Cord blood banking: ethical and cost,benefit aspectsISBT SCIENCE SERIES: THE INTERNATIONAL JOURNAL OF INTRACELLULAR TRANSPORT, Issue 1 2007S. Querol Cord blood represents a new source of stem cells on the edge of fetal and postnatal life. Increasing interest in stem cell therapy has moulded cord blood banking scope, evolving to a multidisciplinary platform exceeding the classic field of haemotherapy. This review intends to re-analyse this and presents the new aspects of cord blood banking that direct it to a model of cell pharmacy in a globalized world. [source] Alpha and beta diversity of arthropods and plants in organically and conventionally managed wheat fieldsJOURNAL OF APPLIED ECOLOGY, Issue 4 2007YANN CLOUGH Summary 1Most studies in applied ecology use measures of ,-diversity measures, i.e. the mean diversity on a site, to compare biodiversity effects of different management schemes. The total or ,-diversity within a region, however, need not be correlated with the mean ,-diversity within any site of the region. Thus, analyses of ,-diversity alone may misrepresent the contributions of other diversity components (,) to total diversity (,). 2We apply a biodiversity-partitioning approach to species richness from a comparison between paired organic and conventional wheat fields in 21 sites from three regions in Germany, where we recorded plants, bees, carabids, staphylinids and spiders in the centre and edge of the fields. 3Relative values of ,- and ,-diversity depended on taxon. Both between-site and between-region ,-diversity were very high (in total 60,85%). ,-Diversity and between-site ,-diversity was larger on the edge than in the centre of fields for all taxa. 4,-Diversity, between-site ,-diversity of plants and bees and between-region ,-diversity of bees were higher in organic than in conventional fields, providing local as well as larger-scale species richness benefits. ,-Diversity did not differ between management types for the epigaeic arthropods. Lower between-site ,-diversity was found for spiders in organic fields than in conventional fields, resulting in higher total species richness in conventionally managed wheat. 5Similarity in composition of landscapes surrounding the study fields was correlated with similarity in species composition for epigaeic arthropods in conventional fields. For this group of organisms the variability of landscapes in the sample contributed to increasing ,-diversity. 6Synthesis and applications.,-Diversity accounts for the major part of species richness in agro-ecosystems. Implementing an agri-environment scheme such as organic agriculture may result in either an additional increase of total diversity, as could be shown for plants and bees, or in a decrease in total diversity as was the case for the spiders. Therefore, ,-diversity needs to be included in the evaluation of different management schemes for conservation. For plant and bees it is recommended to implement agri-environment schemes in contrasting landscapes and in different regions to maximize total species richness benefits. [source] The effects of neighbouring tree islands on pollinator density and diversity, and on pollination of a wet prairie species, Asclepias lanceolata (Apocynaceae)JOURNAL OF ECOLOGY, Issue 3 2006DEREK R. ARTZ Summary 1The Everglades (Florida, USA) is a mosaic of different habitats. Tropical and temperate trees grow on patches of high ground (tree islands) surrounded by lower elevation wetland communities (marl prairie). 2Tree islands of various sizes provide nesting substrate, larval host plants and floral resources for insect pollinators. Herbaceous plants in the open surrounding wetlands may also depend on these pollinators. 3We investigated pollinator diversity and abundances in both tree island and marl prairie habitats using transect sampling methods and estimated pollination success of the milkweed Asclepias lanceolata, an insect-pollinated marl prairie species, in relation to distance from and size of the closest tree island. 4On a total of 11 bayhead tree islands, we found that insect diversity and abundance were greater on the edge of larger tree islands (20,30 m2) than on smaller tree islands (5,10 m2). Pollinator diversity and abundance in the marl prairie decreased with increasing distance from tree islands. 5Pairs of potted A. lanceolata plants were placed in the marl prairie at distances up to 1000 m from small and large tree islands. Fruit and seed production were highest for plants placed less than 25 m from tree islands and decreased with increasing distance. 6Our results suggest that tree islands are an important source of pollinators for the plants in the tree island and surrounding wetland habitats. 7This landscape-based study illustrates how overall landscape structure affects important biotic interactions, particularly plant,pollinator relationships. Our findings have far-reaching ecological implications for the reproductive success of plants in small, isolated populations that may depend on insect vectors for pollination. [source] Diffraction-based automated crystal centeringJOURNAL OF SYNCHROTRON RADIATION, Issue 2 2007Jinhu Song A fully automated procedure for detecting and centering protein crystals in the X-ray beam of a macromolecular crystallography beamline has been developed. A cryo-loop centering routine that analyzes video images with an edge detection algorithm is first used to determine the dimensions of the loop holding the sample; then low-dose X-rays are used to record diffraction images in a grid over the edge and face plane of the loop. A three-dimensional profile of the crystal based on the number of diffraction spots in each image is constructed. The derived center of mass is then used to align the crystal to the X-ray beam. Typical samples can be accurately aligned in ,2,3,min. Because the procedure is based on the number of `good' spots as determined by the program Spotfinder, the best diffracting part of the crystal is aligned to the X-ray beam. [source] Living on the edge: feeding of subtropical open ocean copepodsMARINE ECOLOGY, Issue 2 2006Gustav-Adolf Paffenhöfer Abstract The objective of this study was to provide quantitative information on environmental feeding rates of warm water oceanic epipelagic copepods. We determined clearance rates at 23 °C for various particle size ranges in shipboard studies in the western oligotrophic subtropical Atlantic Ocean for females of the calanoid species Clausocalanus furcatus and Mecynocera clausii. These in situ clearance rates were then applied to the various particle size ranges of environmental particle spectra of auto- and heterotrophs at different depths from three stations in the western Atlantic. After calculating the metabolic demands of each of these two copepod species and applying an assimilation efficiency of 90%, we determined that C. furcatus meets its metabolic demands in all six cases, and M. clausii in two of six cases. Clausocalanus furcatus would also meet its energy demands at 25 °C, where it is often found, while M. clausii at 20 °C, where it is regularly found, would cover its metabolic needs in four of six cases. It is hypothesized that these species, and most likely most of the other co-occurring copepod species, are limited in their abundance by food availability, or, better said, are ,living on the edge' in relation to food abundance. [source] Living on the edge: demographic and phylogeographical patterns in the woodlouse-hunter spider Dysdera lancerotensis Simon, 1907 on the eastern volcanic ridge of the Canary IslandsMOLECULAR ECOLOGY, Issue 15 2007LETICIA BIDEGARAY-BATISTA Abstract The Eastern Canary Islands are the emerged tips of a continuous volcanic ridge running parallel to the northeastern African coast, originated by episodic volcanic eruptions that can be traced back to the Miocene and that, following a major period of quiescence and erosion, continued from the Pliocene to the present day. The islands have been periodically connected by eustatic sea-level changes resulting from Pleistocene glacial cycles. The ground-dwelling spider Dysdera lancerotensis Simon, 1907 occurs along the entire ridge, except on recent barren lavas and sand dunes, and is therefore an ideal model for studying the effect of episodic geological processes on terrestrial organisms. Nested clade and population genetic analyses using 39 haplotypes from 605 base pairs of mitochondrial DNA cytochrome c oxidase I sequence data, along with phylogenetic analyses including two additional mitochondrial genes, uncover complex phylogeographical and demographic patterns. Our results indicate that D. lancerotensis colonized the ridge from north to south, in contrast to what had been expected given the SSW-NNE trend of volcanism and to what had been reported for other terrestrial arthropods. The occurrence of several episodes of extinction, recolonization and expansion are hypothesized for this species, and areas that act as refugia during volcanic cycles are identified. Relaxed molecular clock methods reveal divergence times between main haplotype lineages that suggest an older origin of the northern islets than anticipated based on geological evidence. This study supports the key role of volcanism in shaping the distribution of terrestrial organisms on oceanic islands and generates phylogeographical predictions that warrant further research into other terrestrial endemisms of this fascinating region. [source] Women's narratives on experiences of work ability and functioning in fibromyalgiaMUSCULOSKELETAL CARE, Issue 1 2010Merja Sallinen MSc Abstract Background:,Fibromyalgia is a significant health problem for women of working age. However, little is known about the long-term effects of fibromyalgia in everyday life or on work ability. Methods:,A narrative interview study was conducted to explore the experiences of work ability and functioning of patients with a long history of fibromyalgia. Twenty women, aged 34,65 years, were purposively chosen for the interviews, to reach a wide range of patients with different social and professional backgrounds. Results:,Four types of experience concerning work ability were identified in the narratives: confusion, coping with fluctuating symptoms, being ,in between' and being over the edge of exhaustion. Severe pain and fatigue symptoms, combined with a demanding life situation and ageing, seemed to lead to substantial decrease in work ability and functioning over the long term. In the narratives, vocational rehabilitation or adjustments to work tasks were rarely seen or were started too late to be effective. Conclusions:,Exploring the life stories of women with fibromyalgia can reveal the perceived causes and consequences of fibromyalgia related to work ability or disability, which can be utilized in developing client-centred rehabilitation approaches and effective interventions to support work ability and avoid premature retirement in fibromyalgia patients. Copyright © 2009 John Wiley & Sons, Ltd. [source] Structural order on different length scales in amorphous silicon investigated by Raman spectroscopyPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 3 2010S. Muthmann Abstract Parameters for the structural short (SRO) and medium range order (MRO) of hydrogenated amorphous silicon (a-Si:H) films on the edge of the microcrystalline silicon (µc-Si:H) phase transition were studied with Raman spectroscopy. The observed samples were deposited using radio frequency plasma enhanced chemical vapor deposition. The studied films were grown with various constant and non-constant silane concentrations (SCs). A substrate dependent correlation of SC to the intensity ratio (IMRO) of the transversal acoustical (TA) and the transversal optical (TO) phonon bands was found. A strong correlation between width and position of the (TO) phonon band was observed. These two easily accessible parameters show an increase of SRO when IMRO decreases. [source] The effect of shear on mechanical properties and orientation of HDPE/mica composites obtained via dynamic packing injection molding (DPIM)POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 1 2010Yufang Xiang Abstract The interfacial interaction and orientation of filler play important roles in the enhancement of mechanical performances for polymer/inorganic filler composites. Shear has been found to be a very effective way for the enhancement of interfacial interaction and orientation. In this work, we will report our recent efforts on exploring the development of microstructure of high density polyethylene (HDPE)/mica composites in the injection-molded bars obtained by so-called dynamic packing injection molding (DPIM), which imposed oscillatory shear on the melt during the solidification stage. The mechanical properties were evaluated by tensile testing and dynamic mechanical analysis (DMA), and the crystal morphology, orientation, and the dispersion of mica were characterized by scanning electron microscopy and two-dimensional wide-angle X-ray scattering. Compared with conventional injection molding, DPIM caused an obvious increase in orientation for both HDPE and mica. More importantly, better dispersion and epitaxial crystallization of HDPE was observed on the edge of the mica in the injection-molded bar. As a result, increased tensile strength and modulus were obtained, accompanied with a decrease of elongation at break. The obtained data were treated by Halpin,Tsai model, and it turned out that this model could be also used to predict the stiffness of oriented polymer/filler composites. Copyright © 2009 John Wiley & Sons, Ltd. [source] | |||||||||||||||||||||||||||||||