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Strong Impact (strong + impact)
Selected AbstractsTrivelpiece-Gould mode produced gas-discharges in a diffusion-controlled regimeCONTRIBUTIONS TO PLASMA PHYSICS, Issue 3-4 2003H. Schlüter Abstract The study presents a numerical fluid-plasma model of waveguide discharges sustained by travelling azimuthallysymmetric Trivelpiece-Gould modes. The results describe weakly-magnetized (, , ,e) plasma production in a diffusion-controlled regime (, being the wave frequency, ,e the electron gyro-frequency). However, with respect to the influence of the external magnetic field on the transverse ambipolar-diffusion coefficient, cases of both weak and strong impact of the magnetic field are covered. In its electrodynamical part, the model involves detailed description of the behaviour of the Trivelpiece-Gould waves in radially-inhomogeneous collisional plasmas. The gas-discharge part of the model specifies plasma production in an argon gas. The results are for the self-consistent structure of the discharge composed out of the interrelated variations of wavenumber, space damping rate, plasma density, electron temperature and power absorbed on average by an electron. The analysis is in terms of influence of gas-pressure and magnetic-field changes. [source] Transgenic mice for studies of the renin,angiotensin system in hypertensionACTA PHYSIOLOGICA, Issue 4 2004J. L. Lavoie Abstract Hypertension is a polygenic and multi-factorial disorder that is extremely prevalent in western societies, and thus has received a great deal of attention by the research community. The renin,angiotensin system has a strong impact on the control of blood pressure both in the short- and long-term, making it one of the most extensively studied physiological systems. Nevertheless, despite decades of research, the specific mechanisms implicated in its action on blood pressure and electrolyte balance, as well as its integration with other cardiovascular pathways remains incomplete. The production of transgenic models either over-expressing or knocking-out specific components of the renin,angiotensin system has given us a better understanding of its role in the pathogenesis of hypertension. Moreover, our attention has recently been refocused on local tissue renin,angiotensin systems and their physiological effect on blood pressure and end-organ damage. Herein, we will review studies using genetic manipulation of animals to determine the role of the endocrine and tissue renin,angiotensin system in hypertension. We will also discuss some untraditional approaches to target the renin,angiotensin system in the kidney. [source] Adaptive advantages of myrmecochory: the predator-avoidance hypothesis tested over a wide geographic rangeECOGRAPHY, Issue 5 2005Antonio J. Manzaneda The predator-avoidance hypothesis states that once released from the parent plant, myrmecochorous seeds are rapidly taken by ants to their nests, where they are protected from predators. Previous studies conducted to test this hypothesis have frequently neglected two major aspects necessary for its verification: 1) the influence of processes acting after the seed release and 2) the spatial evenness of such processes. Thus, large-scale variations in the mechanisms acting beyond seed release, and possibly influencing seed escape from predators, remain poorly documented. Here, we present the results of a post-dispersal seed-removal experiment on the myrmecochorous herb Helleborus foetidus, aimed at verifing the predator-avoidance hypothesis by considering two key post-release aspects of seed fate: seed destination (dispersed or nondispersed) and seed burial (buried or not buried). Experiments were performed in four different regions in the Iberian Peninsula. After three days of exposure of seeds to the main predator (fieldmice Apodemus sylvaticus), ca 30% of the seeds were removed. Seed destination affected the proportion of seeds escaping predation, but the sign, magnitude and statistical significance of the effect varied among the geographical regions. In the southern region (Cazorla), seeds dispersed in ant nests or intermediate destinations suffered scarcely any predation, but seeds under reproductive-age plants experienced losses ca 50%. Conversely, in the northern region (Caurel), seeds in nests suffered significantly greater losses than seeds under plants or intermediate destinations, suggesting that nests were especially unsafe destinations. Seed burial had a strong impact on seed escape from predators, and its effect was highly consistent among geographical regions. In view of the consistency of its effect at different spatial scales, seed burial was a more general mechanism for predation avoidance than seed relocation to ant nests, which was habitat- and/or ant-species-dependent. Our results thus only partially support the predator-avoidance hypothesis for the evolution of myrmecochory. [source] Data Mining for Bioprocess OptimizationENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 3 2004S. Rommel Abstract Although developed for completely different applications, the great technological potential of data analysis methods called "data mining" has increasingly been realized as a method for efficiently analyzing potentials for optimization and for troubleshooting within many application areas of process, technology. This paper presents the successful application of data mining methods for the optimization of a fermentation process, and discusses diverse characteristics of data mining for biological processes. For the optimization of biological processes a huge amount of possibly relevant process parameters exist. Those input variables can be parameters from devices as well as process control parameters. The main challenge of such optimizations is to robustly identify relevant combinations of parameters among a huge amount of process parameters. For the underlying process we found with the application of data mining methods, that the moment a special carbohydrate component is added has a strong impact on the formation of secondary components. The yield could also be increased by using 2 m3 fermentors instead of 1 m3 fermentors. [source] Is my antibody-staining specific?EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 12 2008How to deal with pitfalls of immunohistochemistry Abstract Immunohistochemistry is a sensitive and versatile method widely used to investigate the cyto- and chemoarchitecture of the brain. It is based on the high affinity and selectivity of antibodies for a single epitope. However, it is now recognized that the specificity of antibodies needs to be tested in control experiments to avoid false-positive results due to non-specific binding to tissue components or recognition of epitopes shared by several molecules. This ,Technical Spotlight' discusses other pitfalls, which are often overlooked, although they can strongly influence the outcome of immunohistochemical experiments. It also recapitulates the minimal set of information that should be provided in scientific publications to allow proper evaluation and replication of immunohistochemical experiments. In particular, tissue fixation and processing can have a strong impact on antigenicity by producing conformational changes to the epitopes, limiting their accessibility (epitope masking) or generating high non-specific background. These effects are illustrated for an immunoperoxidase staining experiment with three antibodies differing in susceptibility to fixation, using tissue from mice processed under identical conditions, except for slight variations in tissue fixation. In these examples, specific immunostaining can be abolished depending on fixation strength, or detected only after prolonged postfixation. As a consequence, antibody characterization in immunohistochemistry should include their susceptibility towards fixation and determination of the optimal conditions for their use. [source] Dynamics of support for European integration in post-communist PolandEUROPEAN JOURNAL OF POLITICAL RESEARCH, Issue 4 2003KAZIMIERZ M. SLOMCZYNSKI This study examines the dynamics of citizen support for European integration in Poland. Using data from 1995 and 1998 surveys and from a three-wave panel study, we find that, as in Western Europe, both utilitarian calculations of self-interest and political considerations are equally important determinants of support for membership in the European Union. Moreover, between 1995 and 1998 there was considerable polarization of opinion along economic, partisan and ideological lines. We also consider the impact of pro-democratic and pro-capitalist values on support for integration. Our results show that, all things being equal, such values are significant predictors of European Union support. In addition, they have a strong impact on individual-level stability and change in attitudes toward Poland joining the European Union. [source] CYP7B1-mediated metabolism of dehydroepiandrosterone and 5,-androstane-3,,17,-diol , potential role(s) for estrogen signalingFEBS JOURNAL, Issue 8 2008Hanna Pettersson CYP7B1, a cytochrome P450 enzyme, metabolizes several steroids involved in hormonal signaling including 5,-androstane-3,,17,-diol (3,-Adiol), an estrogen receptor agonist, and dehydroepiandrosterone, a precursor for sex hormones. Previous studies have suggested that CYP7B1-dependent metabolism involving dehydroepiandrosterone or 3,-Adiol may play an important role for estrogen receptor ,-mediated signaling. However, conflicting data are reported regarding the influence of different CYP7B1-related steroids on estrogen receptor , activation. In the present study, we investigated CYP7B1-mediated conversions of dehydroepiandrosterone and 3,-Adiol in porcine microsomes and human kidney cells. As part of these studies, we compared the effects of 3,-Adiol (a CYP7B1 substrate) and 7,-hydroxy-dehydroepiandrosterone (a CYP7B1 product) on estrogen receptor , activation. The data obtained indicated that 3,-Adiol is a more efficient activator, thus lending support to the notion that CYP7B1 catalysis may decrease estrogen receptor , activation. Our data on metabolism indicate that the efficiencies of CYP7B1-mediated hydroxylations of dehydroepiandrosterone and 3,-Adiol are very similar. The enzyme catalyzed both reactions at a similar rate and the Kcat/Km values were in the same order of magnitude. A high dehydroepiandrosterone/3,-Adiol ratio in the incubation mixtures, similar to the ratio of these steroids in many human tissues, strongly suppressed CYP7B1-mediated 3,-Adiol metabolism. As the efficiencies of CYP7B1-mediated hydroxylation of dehydroepiandrosterone and 3,-Adiol are similar, we propose that varying steroid concentrations may be the most important factor determining the rate of CYP7B1-mediated metabolism of dehydroepiandrosterone or 3,-Adiol. Consequently, tissue-specific steroid concentrations may have a strong impact on CYP7B1-dependent catalysis and thus on the levels of different CYP7B1-related steroids that can influence estrogen receptor , signaling. [source] The New Economy: Reality and PolicyFISCAL STUDIES, Issue 3 2001John Van Reenen Abstract This paper concerns the new economy (alias the knowledge-based economy). I examine the different meanings attached to the new economy term and the evidence surrounding it, concentrating on the upsurge in US productivity growth between 1995 and 2000. I argue that the reports of the death of the new economy have been greatly exaggerated. There is evidence that information technology has transformed the US economy and is thus likely to have a strong impact on the UK economy in coming years. I discuss how elements of public policy should adapt to these economic changes, both in terms of an overall framework and in applications to specific areas (technology policy, human capital policy, competition policy and industrial policy). The new economy is a place of hope and fear. The hope is that policy activism can cement in potential productivity gains; the fear is that government actions will not mitigate the seemingly ineluctable pressures towards social exclusion. [source] Conversion of hardwood forests to spruce and pine plantations strongly reduced soil methane sink in GermanyGLOBAL CHANGE BIOLOGY, Issue 6 2003WERNER BORKEN Abstract Well-drained forest soils are thought to be a significant sink for atmospheric methane. Recent research suggests that land use change reduces the soil methane sink by diminishing populations of methane oxidizing bacteria. Here we report soil CH4 uptake from ,natural' mature beech forests and from mature pine and spruce plantations in two study areas of Germany with distinct climate and soils. The CH4 uptake rates of both beech forests at Solling and Unterlüß were about two,three times the CH4 uptake rates of the adjacent pine and spruce plantations, indicating a strong impact of forest type on the soil CH4 sink. The CH4 uptake rates of sieved mineral soils from our study sites confirmed the tree species effect and indicate that methanotrophs were mainly reduced in the 0,5 cm mineral soil depth. The reasons for the reduction are still unknown. We found no site effect between Solling and Unterlüß, however, CH4 uptake rates from Solling were significantly higher at the same effective CH4 diffusivity. This potential site effect was masked by higher soil water contents at Solling. Soil pH (H2O) explained 71% of the variation in CH4 uptake rates of sieved mineral soils from the 0,5 cm depth, while cation exchange capacity, soil organic carbon, soil nitrogen and total phosphorous content were not correlated with CH4 uptake rates. Comparing 1998,99, annual CH4 uptake rates increased by 69,111% in the beech and spruce stands and by 5,25% in the pine stands, due primarily to differences in growing season soil moisture. Cumulative CH4 uptake rates from November throughout April were rather constant in both years. The CH4 uptake rates of each stand were separately predicted using daily average soil matric potential and a previously developed empirical model. The model results revealed that soil matric potential explains 53,87% of the temporal variation in CH4 uptake. The differences between measured and predicted annual CH4 uptake rates were less than 10%, except for the spruce stand at Solling in 1998 (17%). Based on data from this study and from the literature, we calculated a total reduction in the soil CH4 sink of 31% for German forests due in part to conversion of deciduous to coniferous forests. [source] Simulating soil-water movement under a hedgerow surrounding a bottomland reveals the importance of transpiration in water balanceHYDROLOGICAL PROCESSES, Issue 5 2008Z. Thomas Abstract The objective of this study was to quantify components of the water balance related to root-water uptake in the soil below a hedgerow. At this local scale, a two-dimensional (2D) flow domain in the x,z plane 6 m long and 1·55 m deep was considered. An attempt was made to estimate transpiration using a simulation model. The SWMS-2D model was modified and used to simulate temporally and spatially heterogeneous boundary conditions. A function with a variable spatial distribution of root-water uptake was considered, and model calibration was performed by adjusting this root-water uptake distribution. Observed data from a previous field study were compared against model predictions. During the validation step, satisfactory agreement was obtained, as the difference between observed and modelled pressure head values was less than 50 cm for 80% of the study data. Hedge transpiration capacity is a significant component of soil-water balance in the summer, when predicted transpiration reaches about 5·6 mm day,1. One of the most important findings is that hedge transpiration is nearly twice that of a forest canopy. In addition, soil-water content is significantly different whether downslope or upslope depending on the root-water uptake. The high transpiration rate was mainly due to the presence of a shallow water table below the hedgerow trees. Soil-water content was not a limiting factor for transpiration in this context, as it could be in one with a much deeper water table. Hedgerow tree transpiration exerts a strong impact not only on water content within the vadose zone but also on the water-table profile along the transect. Results obtained at the local scale reveal that the global impact of hedges at the catchment scale has been underestimated in the past. Transpiration rate exerts a major influence on water balance at both the seasonal and annual scales for watersheds with a dense network of hedgerows. Copyright © 2007 John Wiley & Sons, Ltd. [source] The North Atlantic Oscillation and European vegetation dynamicsINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 14 2008Célia Gouveia Abstract The relationship between vegetation greenness and the North Atlantic Oscillation (NAO) is assessed over Europe. The study covers the 21-year period from 1982 to 2002 and is based on monthly composites of the Normalised Difference Vegetation Index (NDVI) and Brightness Temperature from the Global Inventory Monitoring and Modelling System (GIMMS) as well as on monthly precipitation from the Global Precipitation Climatology Centre (GPCC). A systematic analysis is first performed of point correlation fields over the 21-year period between the winter NAO index and spring and summer NDVI, followed by an assessment of the vegetation response to precipitation and temperature conditions in winter, over two contrasting regions, namely the Iberian Peninsula and Northeastern Europe. Finally, the impact of NAO on vegetation dynamics over the two regions is evaluated by studying the corresponding annual cycles of NDVI and comparing their behaviour for years associated with opposite NAO phases. Over the Iberian Peninsula there is strong evidence that positive (negative) values of winter NAO induce low (high) vegetation activity in the following spring and summer seasons. This feature is mainly associated with the impact of NAO on winter precipitation, together with the strong dependence of spring and summer NDVI on water availability during the previous winter. Northeastern Europe shows a different behaviour, with positive (negative) values of winter NAO inducing high (low) values of NDVI in spring, but low (high) values of NDVI in summer. This behaviour mainly results from the strong impact of NAO on winter temperature, associated with the critical dependence of vegetation growth on the combined effect of warm conditions and water availability during the winter season. Copyright © 2008 Royal Meteorological Society [source] Subtropical cold surges: regional aspects and global distributionINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 10 2001René 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] Agrarian Transformation and Rural Diversity in Globalizing East AsiaINTERNATIONAL JOURNAL OF JAPANESE SOCIOLOGY, Issue 1 2004Atsushi Kitahara Abstract:, In East Asia the rural society is not a society based upon agricultural industry anymore and the peasant society with its long history has been disappearing. The occupation and income sources of rural inhabitants have diversified and among them those who specialized in farming are the minority. There is a shortage of rural labor, which used to be abundant in the past, and presently it is not as easy to hire the farm workers. The reason for the diversification of the rural occupations is, to put it simply, because people cannot live merely on farm income. Indeed the farm operation costs have become more expensive due to labor saving techniques, but the livelihood costs have become more expensive due the new uniform lifestyle standards from globalization. Electric machines and education are the typical of these increased costs. The background of this rural change is industrialization and urbanization in the context of globalization and its strong impact is penetrating into the rural society through the regional urban center as the relay point of the global mechanism. This change is different based upon the location of each rural society. Generally, rural societies around a big urban center enjoy opportunities for the younger generation, but remote areas have serious problems with few employment opportunities and a smaller youth population. To reproduce and sustain the regional society as a whole, it is necessary to attract younger people and make them stay. We should plan to develop a variety of industries and the resultant diversified work opportunities in the broader region beyond the narrowly demarcated village and community. Subsistence and commercial agriculture might merely be a part of such diversity. [source] A model of wine tourist behaviour: a festival approachINTERNATIONAL JOURNAL OF TOURISM RESEARCH, Issue 3 2008Jingxue (Jessica) Yuan Abstract The study constructs a temporal model of wine tourist behaviour on the basis of the social psychologist' theory of consumer attitudes and related concepts with regard to past behaviour, satisfaction, perceived value and behavioural intentions. More importantly, this study added two dimensions to this model by proposing that satisfaction and perceived value had an impact on the attendees' intentions (i) to visit a local winery and (ii) to buy local wine products. Using a path analysis approach and data collected from the attendees at a regional wine festival, the study examined the above relationships. The results of this path analysis can be summarised as: (i) past behaviour influenced the intention to revisit and the level of perceived value, but had no effect on the level of satisfaction; (ii) perceived value strongly affected the level of satisfaction; (iii) satisfaction had a strong impact on future intentions to revisit and also an effect on intentions to visit local wineries and to buy local wine products; and (iv) perceived value affected the intentions to revisit the festival and to visit local wineries but did not influence the intentions to buy local wines. It is believed that the results of the present study will be useful to organisers of wine festivals and/or wine tourism developers. Copyright © 2008 John Wiley & Sons, Ltd. [source] Leaf Decomposition in a Mountain Stream in the Sultanate of OmanINTERNATIONAL REVIEW OF HYDROBIOLOGY, Issue 1 2009Maha Al-Riyami Abstract Decomposition of Juglans regia leaves was studied in fine and coarse mesh bags in a permanent mountain stream in Oman. A rapid initial mass loss, attributed to leaching, was followed by a more gradual decline. Daily exponential decay rates (k) calculated over 32 days were 0.011 (fine mesh litter bags) and 0.014 (coarse mesh litter bags). The difference between bag types was not significant, suggesting limited impact of leaf-shredding invertebrates. Ergosterol levels on leaves from fine mesh bags peaked at 0.3 mg g,1 AFDM after 16 days of stream exposure. During the experimental period, which followed the annual leaf fall, the concentration of aquatic hyphomycete conidia in the stream varied between 82 and 1362 l,1. Based on the morphology of conidia found in the water column or released from leaves, we identified 14 species of aquatic hyphomycetes. Tetracladium apiense was the most common taxon (62.2% of conidia in water column during the field experiment). Three other Tetracladium species contributed another 8%. Plating out leaf particles yielded common epiphytic taxa such as Alternaria sp., Aureobasidium pullulans and Phoma sp. The measured metrics of leaf decay in this desert stream fall within the range of values observed in temperate and tropical streams, with clear evidence for an early leaching phase, and no evidence of a strong impact of leaf shredders. The community of aquatic hyphomycetes appears impoverished. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Stochastic analysis of crude oil procurement and processing under uncertain demand for bunker fuel oilINTERNATIONAL TRANSACTIONS IN OPERATIONAL RESEARCH, Issue 5 2006Bernardo Zimberg Abstract Bunker fuel oil (ifo), one of the products of petroleum refining, has a strong impact in the production process because it drives the availability of heavy residues that depend on the crude quality. A simplified stochastic model for the Administración Nacional de Combustibles Alcohol y Portland refinery, based on the uncertainty of the demand for ifo, is proposed for comparison with the current approach of deterministic demand. In this model, the benefits of the production process are maximized, taking decisions on the more suitable raw material, intermediate products and final blends in order to fulfill quality and demand requirements of final products. A specific case is analyzed where the maximum benefit is achieved when the most expensive crude quality is purchased, due to a lack of incentive to produce extra amounts of heavy fuel oil that must be exported at a non-attractive price. Results are compared with the solution of a deterministic model with mean demand. In addition, the stochastic model solution depicts how the refinery should operate for each scenario of ifo demand. [source] Soluble protein oligomers as emerging toxins in alzheimer's and other amyloid diseasesIUBMB LIFE, Issue 4-5 2007Sergio T. Ferreira Abstract Amyloid diseases are a group of degenerative disorders characterized by cell/tissue damage caused by toxic protein aggregates. Abnormal production, processing and/or clearance of misfolded proteins or peptides may lead to their accumulation and to the formation of amyloid aggregates. Early histopathological investigation of affected organs in different amyloid diseases revealed the ubiquitous presence of fibrillar protein aggregates forming large deposits known as amyloid plaques. Further in vitro biochemical and cell biology studies, as well as studies using transgenic animal models, provided strong support to what initially seemed to be a solid concept, namely that amyloid fibrils played crucial roles in amyloid pathogenesis. However, recent studies describing tissue-specific accumulation of soluble protein oligomers and their strong impact on cell function have challenged the fibril hypothesis and led to the emergence of a new view: Fibrils are not the only toxins derived from amyloidogenic proteins and, quite possibly, not the most important ones with respect to disease etiology. Here, we review some of the recent findings and concepts in this rapidly developing field, with emphasis on the involvement of soluble oligomers of the amyloid-, peptide in the pathogenesis of Alzheimer's disease. Recent studies suggesting that soluble oligomers from different proteins may share common mechanisms of cytotoxicity are also discussed. Increased understanding of the cellular toxic mechanisms triggered by protein oligomers may lead to the development of rational, effective treatments for amyloid disorders. IUBMB Life, 59: 332-345, 2007 [source] A Single EU Seat in the IMF?JCMS: JOURNAL OF COMMON MARKET STUDIES, Issue 2 2004Lorenzo Bini Smaghi This article examines the rationale for consolidating EU Member States' position in the International Monetary Fund (IMF). Although a substantial amount of co-ordination already takes place, particularly on issues related to the euro area and the single monetary and exchange rate policy, co-operation between EU countries in the IMF remains a relatively new phenomenon and divergences still prevail. The current institutional set-up, whereby the 15 EU countries are spread in nine constituencies, undermines effectiveness. Al though there is scope for further improving co-operation, there are natural limits to what can be achieved within the existing co-operation frame work. A single EU constituency would enable EU Member States to have a strong impact on IMF policies, potentially as strong as that of the US. However, this may not be an objective for all EU countries in the current conjuncture. [source] The role of trout in stream food webs: integrating evidence from field surveys and experimentsJOURNAL OF ANIMAL ECOLOGY, Issue 2 2006KRISTIAN MEISSNER Summary 1We evaluated the effects of brown trout on boreal stream food webs using field surveys and enclosure/exclosure experiments. Experimental results were related to prey preference of uncaged trout in the same stream, as well as to a survey of macroinvertebrate densities in streams with vs. without trout. Finally, we assessed the generality of our findings by examining salmonid predation on three groups of macroinvertebrate prey (chironomid midges, epibenthic grazers, invertebrate predators) in a meta-analysis. 2In a preliminary experiment, invertebrate predators showed a strong negative response to trout, whereas chironomids benefited from trout presence. In the main experiment, trout impact increased with prey size. Trout had the strongest effect on invertebrate predators and cased caddis larvae, whereas Baetis mayfly and chironomid larvae were unaffected. Trout impact on the largest prey seemed mainly consumptive, because prey emigration rates were low and independent of fish presence. Despite strong effects on macroinvertebrates, trout did not induce a trophic cascade on periphyton. Uncaged trout showed a strong preference for the largest prey items (predatory invertebrates and aerial prey), whereas Baetis mayflies and chironomids were avoided by trout. 3Densities of invertebrate predators were significantly higher in troutless streams. Baetis mayflies also were less abundant in trout streams, whereas densities of chironomids were positively, although non-significantly, related to trout presence. Meta-analysis showed a strong negative impact of trout on invertebrate predators, a negative but variable impact on mobile grazers (mainly mayfly larvae) and a slightly positive impact on chironomid larvae. 4Being size-selective predators, salmonid fishes have a strong impact on the largest prey types available, and this effect spans several domains of scale. Discrepancies between our experimental findings and those from the field survey and meta-analysis show, however, that for most lotic prey, small-scale experiments do not reflect fish impact reliably at stream-wide scales. 5Our findings suggest that small-scale experiments will be useful only if the experimental results are evaluated carefully against natural history information about the experimental system and interacting species across a wide array of spatial scales. [source] Participation and study decisions in a public system of higher educationJOURNAL OF APPLIED ECONOMETRICS, Issue 3 2010Stijn Kelchtermans We analyze the decision whether to participate and where and what to study in a public system of higher education, based on a unique dataset of all eligible high school pupils in an essentially closed region (Flanders). We find that pupils perceive the available institutions and programs as close substitutes relative to the outside option. This implies an ambiguous role for travel costs: they hardly affect the participation decision, but have a strong impact on the decision where and what to study. To illustrate how our empirical results can inform the debate on reforming public systems, we assess the effects of tuition fee increases. Uniform cost-based tuition fee increases achieve most of the welfare gains; the additional gains from fee differentiation are relatively limited. These welfare gains are quite large under conservative assumptions on the social cost of public funds, and there is a substantial redistribution from students to outsiders. Copyright © 2009 John Wiley & Sons, Ltd. [source] The heat of the moment: the effect of sexual arousal on sexual decision makingJOURNAL OF BEHAVIORAL DECISION MAKING, Issue 2 2006Dan Ariely Abstract Despite the social importance of decisions taken in the "heat of the moment," very little research has examined the effect of sexual arousal on judgment and decision making. Here we examine the effect of sexual arousal, induced by self-stimulation, on judgments and hypothetical decisions made by male college students. Students were assigned to be in either a state of sexual arousal or a neutral state and were asked to: (1) indicate how appealing they find a wide range of sexual stimuli and activities, (2) report their willingness to engage in morally questionable behavior in order to obtain sexual gratification, and (3) describe their willingness to engage in unsafe sex when sexually aroused. The results show that sexual arousal had a strong impact on all three areas of judgment and decision making, demonstrating the importance of situational forces on preferences, as well as subjects' inability to predict these influences on their own behavior. Copyright © 2005 John Wiley & Sons, Ltd. [source] Nested assemblages of Orthoptera species in the Netherlands: the importance of habitat features and life-history traitsJOURNAL OF BIOGEOGRAPHY, Issue 11 2007M. A. Schouten Abstract Aim, Species communities often exhibit nestedness, the species found in species-poor sites representing subsets of richer ones. In the Netherlands, where intensification of land use has led to severe fragmentation of nature, we examined the degree of nestedness in the distribution of Orthoptera species. An assessment was made of how environmental conditions and species life-history traits are related to this pattern, and how variation in sampling intensity across sites may influence the observed degree of nestedness. Location, The analysis includes a total of 178 semi-natural sites in the Pleistocene sand region of the Netherlands. Methods, A matrix recording the presence or absence of all Orthoptera species in each site was compiled using atlas data. Additionally, separate matrices were constructed for the species of suborders Ensifera and Caelifera. The degree of nestedness was measured using the binmatnest calculator. binmatnest uses an algorithm to sort the matrices to maximal nestedness. We used Spearman's rank correlations to evaluate whether sites were sorted by area, isolation or habitat heterogeneity, and whether species were sorted by their dispersal ability, rate of development or degree of habitat specificity. Results, We found the Orthoptera assemblages to be significantly nested. The rank correlation between site order and sampling intensity was high. The degree of nestedness was lower, but remained significant when under- and over-sampled sites were excluded from the analysis. Site order was strongly correlated with both size of sample site and number of habitat types per site. Rank correlations showed that species were probably ordered by variation in habitat specificity, rather than by variation in dispersal capacity or rate of development of the species. Main conclusions, Variation in sampling intensity among sites had a strong impact on the observed degree of nestedness. Nestedness in habitats may underlie the observed nestedness within the Orthoptera assemblages. Habitat heterogeneity is closely related to site area, which suggests that several large sites should be preserved, rather than many small sites. Furthermore, the results corroborate a focus of nature conservation policy on sites where rare species occur, as long as the full spectrum of habitat conditions and underlying ecological processes is secured. [source] Supercritical water for environmental technologiesJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 5 2010Dr Anne Loppinet-Serani Abstract OVERVIEW: Supercritical water is a great medium in which to perform chemical reactions and to develop processes. Due to its unique thermo-physico-chemical properties, supercritical water is able to play the role of solvent of organic compounds and/or to react with them. These specific properties have been used since the 1990s to develop new technologies dedicated to the environment and energy. IMPACT: Supercritical water based technologies are innovative and efficient processes having a strong impact on society, the environment and the economy, and is termed a sustainable technology. APPLICATIONS: Three main applications for supercritical water technology are under development: (i) supercritical water oxidation (SCWO); (ii) supercritical water biomass gasification (SCBG); and (iii) hydrolysis of polymers in supercritical water (HPSCW) for composites/plastics recycling. In this paper some fundamentals of supercritical water are first presented to introduce the above three major developments. Then these technologies are reviewed in terms of their present and future industrial development and their impact on the environment and on energy production. Copyright © 2010 Society of Chemical Industry [source] Noninvasive Diagnosis of Large Esophageal Varices by Fibroscan: Strong Influence of the Cirrhosis EtiologyALCOHOLISM, Issue 7 2010Eric Nguyen-Khac Background:, Large esophageal varices (LOV) were diagnosed by endoscopy in patients with cirrhosis. Noninvasive method would be valuable. Aims:, To evaluate the diagnostic performance of Fibroscan for LOV prediction and to investigate the prognostic value of liver stiffness (LS) in cirrhosis. Patients and Methods:, One hundred and eighty-three patients with cirrhosis (103 alcohol, 58 viral, and 22 others) underwent an endoscopy and a Fibroscan. Of those patients, 41 (22.4%) had LOV. Results:, Median LS was 33.66 kPa (range: 12,75), higher in patients with LOV than those without (51.24 ± 1.61 vs. 29.81 ± 1.82 kPa, p < 0.0001), and in alcoholic than nonalcoholic (40.39 ± 1.75 vs. 25.73 ± 1.82, p < 0.0001). In whole population, a LS ,48 kPa predicted LOV with sensitivity, specificity, positive, negative predictive values (PPV, NPV) of 73.2, 73.2, 44.1, and 90.4%, respectively, and an area under ROC curve (AUROC) of 0.75 (CI 95%: 0.69,0.82). For alcoholic cirrhosis, LS was ,47.2 kPa with sensitivity, specificity, PPV, NPV of 84.6, 63.6, 44, and 92.5%, respectively, AUROC 0.77 (0.68,0.85). For viral cirrhosis, a LS ,19.8 kPa generated diagnostic values of 88.9, 55.1, 26.7, and 96.4% and 0.73 (0.60,0.84). Sixteen (8.75%) patients died at 1 year. In multivariate analysis, LS was not predictive of mortality. Conclusions:, Etiology of cirrhosis has strong impact on LS cutoff for diagnosis of LOV. Studies should be performed with homogenous cirrhosis etiology. [source] Students' Drinker Prototypes and Alcohol Use in a Naturalistic SettingALCOHOLISM, Issue 1 2010Renske Spijkerman Background:, Perceptions about the type of people who drink, also referred to as drinker prototypes, may strengthen young people's motivation to engage in alcohol use. Previous research has shown that drinker prototypes are related to alcohol consumption in both adolescents and young adults. However, the evidence for the strength of these relationships remains inconclusive. One of the caveats in former studies is that all insights about prototype relations are based on self-reported data from youngsters themselves, mostly gathered in a class situation, which may contain bias due to memory distortions and self-presentation concerns. Methods:, The present study examined the impact of drinker prototypes on young adults' drinking patterns by using a less obtrusive measure to assess alcohol consumption, i.e. ad lib drinking among friend groups in the naturalistic setting of a bar lab. Drinker prototypes, self-reported alcohol use in the past, and observed alcohol intake in the bar lab were assessed among 200 college students. Relations between participants' drinker prototypes and their self-reported and observed drinking behavior were examined by computing correlations and conducting multilevel analyses. Results:, Drinker prototypes were related to both self-reported and observed alcohol use. However, the drinking patterns of friend group members had a strong impact on participants' individual drinking rates in the bar lab. After these group effects had been controlled for, only heavy drinker prototypes showed relations with observed alcohol intake in the bar lab. Conclusions:, These findings further establish the value of drinker prototypes in predicting young adults' drinking behavior and suggest that people's motivation to drink alcohol in real-life drinking situations is related to their perceptions about heavy drinkers. [source] The primary care nurse practitioner and cancer survivorship careJOURNAL OF THE AMERICAN ACADEMY OF NURSE PRACTITIONERS, Issue 8 2010CRNP (Family Nurse Practitioner), Joanna M. Cooper MS Abstract Purpose: To examine the important role that primary care nurse practitioners (NPs) have in providing long-term surveillance and health maintenance for breast, prostate, and colorectal cancer survivors throughout the continuum of cancer care. Data sources: MEDLINE, CINAHL, MD-Consult, and Cochrane's databases were utilized with the inclusion of primary research and critical research reviews from January 1995 through March 2008. Select organizational websites were also cited. Conclusions: Cancer patients experience changes in the focus of their care when management shifts from the treatment of cancer to management of treatment side effects and outcomes, to survivorship care, and to secondary cancer treatment. NPs have a strong impact on cancer survivorship care by serving in various roles and settings throughout the cancer trajectory to improve patient outcomes. Implications for practice: Cancer survivorship care expands beyond specialty settings, into primary care. NPs have a key role in ensuring continuity of care for patients with cancer. Models of care that promote continuity and high quality of care for patients with cancer include the shared-care and nurse-managed health center models. The formal collaborative plan of care is essential in long-term cancer survivorship care. [source] Grain-Boundary Wetting-Dewetting in z= 1 SiAlON CeramicJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 12 2002Hans-Joachim Kleebe The grain-boundary structure of a model SiAlON polycrystal with nominal composition Si5AlON7 was characterized by transmission electron microscopy (TEM) both in an equilibrium (as-processed) state at room temperature and after quenching from elevated temperature. In addition, low-frequency (1,13 Hz) internal friction data were recorded as a function of temperature, showing a pronounced grain-boundary sliding peak positioned at 1030°C. High-resolution transmission electron microscopy (HRTEM) of the equilibrated low-temperature microstructure revealed residual glass only at multigrain junctions, but no amorphous intergranular films were observed. The detection of clean interfaces in the as-processed sample contradicts the internal friction data, which instead suggests the presence of a low-viscosity grain boundary phase, sliding at elevated temperatures. Therefore, a thin section of the as-sintered material was heated to 1380°C and rapidly quenched. HRTEM analysis of this sample showed, apart from residual glass pockets, wetted grain boundaries, which is in line with the internal friction experiment. This wetting-dewetting phenomenon observed in z= 1 SiAlON is expected to have a strong impact not only on high-temperature engineering ceramics but also on geological, temperature-activated processes such as volcanic eruptions. [source] Institutional Quality and the Gains from TradeKYKLOS INTERNATIONAL REVIEW OF SOCIAL SCIENCES, Issue 3 2006Axel Borrmann SUMMARY While theoretical models suggest that trade is likely to increase productivity and income levels, the empirical evidence is rather mixed. For some countries, trade has a strong impact on growth, whereas for other countries there is no or even a negative linkage. We examine one likely prerequisite for a welfare increasing impact of trade, that is, the role of institutional quality. Using several model specifications, including an instrumental variable approach, we identify those aspects of institutional quality that matter most for the positive linkage between trade and growth. We find that, above all, labour market regulation is the key to reducing trade-related adjustment costs. Market entry regulations, the efficiency of the tax system, the rule of law and government effectiveness do play a role too. In essence, the results demonstrate that countries with low-quality institutions do not benefit from trade. [source] Preauthoritarian Institutions and Postauthoritarian Outcomes: Labor Politics in Chile and UruguayLATIN AMERICAN POLITICS AND SOCIETY, Issue 1 2008Paul G. Buchanan ABSTRACT The article argues that preauthoritarian institutions have strongly influenced postauthoritarian labor politics in Chile and Uruguay. The nature of preauthoritarian labor administration,state corporatist in Chile, pluralist in Uruguay,had a strong impact on postauthoritarian collective outcomes, whether or not they were modified by the dictators or the ideological disposition of the postauthoritarian governments. Variation in preauthoritarian labor politics between Chile and Uruguay gave historical foundation to different union fortunes in the postauthoritarian era. That result points to the contemporary influence of preauthoritarian institutions, with or without authoritarian modifiers. [source] Reciprocative sliding friction and wear properties of electrical discharge machined ZrO2 -based compositesLUBRICATION SCIENCE, Issue 9 2009Koenraad Bonny Abstract Hot-pressed, laboratory-made, ZrO2 -based composites with 40 vol. % WC, TiCN or TiN were surface finished by electrical discharge machining in order to compare their reciprocating sliding friction and wear response against WC,6wt%Co cemented carbide in unlubricated conditions. Sliding experiments were performed using a Plint TE77 pin-on-flat wear test rig, revealing a strong impact of the secondary phase on the tribological behaviour of the ZrO2 -based composites. The worn surfaces and wear debris were characterised by scanning electron microscopy, energy dispersive X-ray analysis and surface topography scanning, pointing out abrasion, polishing and adhesion as main wear mechanisms. The most favourable friction and wear characteristics were encountered with ZrO2,WC composites compared to the other grades with equal amount of volumetric secondary phase. Copyright © 2009 John Wiley & Sons, Ltd. [source] | ||||||||||||||||||||||||||||||||||||||||||||||