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Selected AbstractsRange size, taxon age and hotspots of neoendemism in the California floraDIVERSITY AND DISTRIBUTIONS, Issue 3 2010Nathan J. B. Kraft Abstract Aim, Sustaining biological diversity requires the protection of the ecological, evolutionary and landscape-level processes that generate it. Here, we identify areas of high neoendemism in a global diversity hotspot, the California flora, using range size data and molecular-based estimates of taxon age. Location, California, USA. Methods, We compiled distribution and range size data for all plant taxa endemic to California and internal transcribed spacer (ITS)-based age estimates for 337 putative neoendemics (15% of the endemic flora). This information was combined to identify areas in the state with high proportions of young and restricted-range taxa. We overlaid the distribution of neoendemic hotspots on maps of currently protected lands and also explored correlations between our diversity measures and climate. Results, The central coast of California, the Sierra Nevada and the San Bernardino Range contained endemics with the most restricted distributions on average, while areas in the Desert and Great Basin provinces found within the state were composed of the youngest neoendemics on average. Diversity measures that took age and range size into account shifted the estimate of highest endemic diversity in the state towards the Desert and Great Basin regions relative to simple counts of endemic species richness. Our diversity measures were poorly correlated with climate and topographic heterogeneity. Main conclusions, Substantial portions of California with high levels of plant neoendemism fall outside of protected lands, indicating that additional action will be needed to preserve the geographic areas apparently associated with high rates of plant diversification. The neoendemic flora of the deserts appears particularly young in our analyses, which may reflect the relatively recent origin of desert environments within the state. [source] Nonlinear epigenetic variance: review and simulationsDEVELOPMENTAL SCIENCE, Issue 1 2010Kees-Jan Kan We present a review of empirical evidence that suggests that a substantial portion of phenotypic variance is due to nonlinear (epigenetic) processes during ontogenesis. The role of such processes as a source of phenotypic variance in human behaviour genetic studies is not fully appreciated. In addition to our review, we present simulation studies of nonlinear epigenetic variance using a computational model of neuronal network development. In each simulation study, time series for monozygotic and dizygotic twins were generated and analysed using conventional behaviour genetic modelling. In the results of these analyses, the nonlinear epigenetic variance was subsumed under the non-shared environmental component. As is commonly found in behaviour genetic studies, observed heritabilities and unique environmentabilities increased with time, whereas common environmentabilities decreased. The fact that the phenotypic effects of nonlinear epigenetic processes appear as unsystematic variance in conventional twin analyses complicates the identification and quantification of the ultimate genetic and environmental causes of individual differences. We believe that nonlinear dynamical system theories provide a challenging perspective on the development of individual differences, which may enrich behaviour genetic studies. [source] Optimal Incentive Contracts for Loss-Averse Managers: Stock Options versus Restricted Stock GrantsFINANCIAL REVIEW, Issue 4 2006Anna Dodonova G39; M52 Abstract This paper provides an explanation for the widespread use of stock option grants in executive compensation. It shows that the optimal incentive contract for loss-averse managers must contain a substantial portion of stock options even when it should consist exclusively of stock grants for "classical" risk-averse managers. The paper also provides an explanation for the drastic increase in the risk-adjusted level of CEO compensations over the past two decades and argues that more option-based compensation should be used in firms with higher cash flow volatility and in industries with a higher degree of heterogeneity among firms. [source] Interactions between fauna and sediment control the breakdown of plant matter in river sedimentsFRESHWATER BIOLOGY, Issue 4 2010SIMON NAVEL Summary 1. A substantial portion of particulate organic matter (POM) is stored in the sediment of rivers and streams. Leaf litter breakdown as an ecosystem process mediated by microorganisms and invertebrates is well documented in surface waters. In contrast, this process and especially the implication for invertebrates in subsurface environments remain poorly studied. 2. In the hyporheic zone, sediment grain size distribution exerts a strong influence on hydrodynamics and habitability for invertebrates. We expected that the influence of shredders on organic matter breakdown in river sediments would be influenced strongly by the physical structure of the interstitial habitat. 3. To test this hypothesis, the influence of gammarids (shredders commonly encountered in the hyporheos) on degradation of buried leaf litter was measured in experimental systems (slow filtration columns). We manipulated the structure of the sedimentary habitat by addition of sand to a gravel-based sediment column to reproduce three conditions of accessible pore volume. Ten gammarids were introduced in columns together with litter bags containing alder leaves at a depth of 8 cm in sediment. Leaves were collected after 28 days to determine leaf mass loss and associated microbial activity (fungal biomass, bacterial abundance and glucosidase, xylosidase and aminopeptidase activities). 4. As predicted, the consumption of buried leaf litter by shredders was strongly influenced by the sediment structure. Effective porosity of 35% and 25% allowed the access to buried leaf litter for gammarids, whereas a lower porosity (12%) did not. As a consequence, leaf litter breakdown rates in columns with 35% and 25% effective porosity were twice as high as in the 12% condition. Microbial activity was poorly stimulated by gammarids, suggesting a low microbial contribution to leaf mass loss and a direct effect of gammarids through feeding activity. 5. Our results show that breakdown of POM in subsurface waters depends on the accessibility of food patches to shredders. [source] Implications of CO2 fertilization for future climate change in a coupled climate,carbon modelGLOBAL CHANGE BIOLOGY, Issue 5 2007H. DAMON MATTHEWSArticle first published online: 28 FEB 200 Abstract The terrestrial carbon cycle plays a critical role in determining levels of atmospheric CO2 that result from anthropogenic carbon emissions. Elevated atmospheric CO2 is thought to stimulate terrestrial carbon uptake, through the process of CO2 fertilization of vegetation productivity. This negative carbon cycle feedback results in reduced atmospheric CO2 growth, and has likely accounted for a substantial portion of the historical terrestrial carbon sink. However, the future strength of CO2 fertilization in response to continued carbon emissions and atmospheric CO2 rise is highly uncertain. In this paper, the ramifications of CO2 fertilization in simulations of future climate change are explored, using an intermediate complexity coupled climate,carbon model. It is shown that the absence of future CO2 fertilization results in substantially higher future CO2 levels in the atmosphere, as this removes the dominant contributor to future terrestrial carbon uptake in the model. As a result, climate changes are larger, though the radiative effect of higher CO2 on surface temperatures in the model is offset by about 30% due to reduced positive dynamic vegetation feedbacks; that is, the removal of CO2 fertilization results in less vegetation expansion in the model, which would otherwise constitute an important positive surface albedo-temperature feedback. However, the effect of larger climate changes has other important implications for the carbon cycle , notably to further weaken remaining carbon sinks in the model. As a result, positive climate,carbon cycle feedbacks are larger when CO2 fertilization is absent. This creates an interesting synergism of terrestrial carbon cycle feedbacks, whereby positive (climate,carbon cycle) feedbacks are amplified when a negative (CO2 fertilization) feedback is removed. [source] Treating hepatitis C in the prison population is cost-saving,HEPATOLOGY, Issue 5 2008Jennifer A. Tan The prevalence of chronic hepatitis C infection in U.S. prisons is 12% to 31%. Treatment of this substantial portion of the population has been subject to much controversy, both medically and legally. Studies have demonstrated that treatment of chronic hepatitis C with pegylated interferon (PEG IFN) and ribavirin is a cost-effective measure in the general population; however, no study has addressed whether the same is true of the prison population. The aim of this study was to determine the cost-effectiveness of hepatitis C treatment with PEG IFN and ribavirin in the U.S. prison population. Cost-effectiveness was determined via a decision analysis model employing Markov simulation. The cohort of prisoners had a distribution of genotypes and stages of fibrosis in accordance with prior studies evaluating inmate populations. The probability of transitioning from one health state to another, reinfection rates, in-prison and out-of-prison mortality rates, sustained viral response rates, costs, and quality of life weights were also obtained from the literature. Sensitivity analysis was performed. In a strategy without a pretreatment liver biopsy, treatment was cost-effective for all ages and genotypes. This model was robust to rates of disease progression, mortality rates, reinfection rates, sustained viral response rates, and costs. In a strategy employing a pretreatment liver biopsy, treatment was also cost-saving for prisoners of all ages and genotypes with portal fibrosis, bridging fibrosis, or compensated cirrhosis. Treatment was not cost-effective in patients between the ages of 40 and 49 with no fibrosis and genotype 1. Conclusion: Treatment of chronic hepatitis C with PEG IFN and ribavirin in U.S. prisons results in both improved quality of life and savings in cost for almost all segments of the inmate population. If the decision to treat hepatitis C is based on pharmaco-economic measures, this significant proportion of infected individuals should not be denied access to therapy. (HEPATOLOGY 2008.) [source] Analysis and comparison of morphological reconstructions of hippocampal field CA1 pyramidal cellsHIPPOCAMPUS, Issue 3 2005José Ambros-Ingerson Abstract Morphological reconstructions have become a routine and valuable tool for neuroscientists. The accuracy of reconstructions is a matter of considerable interest given that they are widely used in computational studies of neural function. Despite their wide usage, comparisons of reconstructions obtained using various methodologies are lacking. We reviewed reconstructions of hippocampal CA1 pyramidal cells from five published studies and found marked differences in some of the most basic measurements. For four of the five studies means of total cell length clustered in the 11,479,13,417-,m range. The remaining study had a significantly larger value for this index at 16,992 ± 5,788 ,m. Surface area means varied more than 4-fold from 16,074 to 67,102 ,m2. Volume means varied more than 8-fold from 3,828 to 30,384 ,m3. Simulated passive input resistance means varied from 38.0 to 172.1 M,, reflecting the variability in cell dimensions. Estimates of the electrotonic length varied from 1.26 to 1.56. In two reconstructions used in previously published studies, simulated somatic excitatory postsynaptic potentials (EPSPs) varied 2,4-fold in amplitude, time to peak and half-width, for synaptic inputs at similar locations. Substantial jitter on the z -axis was identified as one likely source of the discrepancy in total cell length, while substantial differences in diameter measurements across studies, and sometimes within the same study, accounted for the variability in surface area and volume. While some part of the observed variability is surely due to the diversity of CA1 pyramidal cells, our analysis suggests that a substantial portion stemmed from methodological inconsistencies and from technological limitations. Suggestions are made for improving the quality and usefulness of morphological reconstructions. We conclude that reconstructions across studies have substantial variability in measures that are very relevant to neuronal function. Consequently, modelers are advised to use more than just one reconstructed cell in their simulations of neural function. © 2004 Wiley-Liss, Inc. [source] Mutation frequencies of X-linked mental retardation genes in families from the EuroMRX consortium,,HUMAN MUTATION, Issue 2 2007Arjan P.M. de Brouwer Abstract The EuroMRX family cohort consists of about 400 families with non-syndromic and 200 families with syndromic X-linked mental retardation (XLMR). After exclusion of Fragile X (Fra X) syndrome, probands from these families were tested for mutations in the coding sequence of 90 known and candidate XLMR genes. In total, 73 causative mutations were identified in 21 genes. For 42% of the families with obligate female carriers, the mental retardation phenotype could be explained by a mutation. There was no difference between families with (lod score >2) or without (lod score <2) significant linkage to the X chromosome. For families with two to five affected brothers (brother pair=BP families) only 17% of the MR could be explained. This is significantly lower (P=0.0067) than in families with obligate carrier females and indicates that the MR in about 40% (17/42) of the BP families is due to a single genetic defect on the X chromosome. The mutation frequency of XLMR genes in BP families is lower than can be expected on basis of the male to female ratio of patients with MR or observed recurrence risks. This might be explained by genetic risk factors on the X chromosome, resulting in a more complex etiology in a substantial portion of XLMR patients. The EuroMRX effort is the first attempt to unravel the molecular basis of cognitive dysfunction by large-scale approaches in a large patient cohort. Our results show that it is now possible to identify 42% of the genetic defects in non-syndromic and syndromic XLMR families with obligate female carriers. © 2007 Wiley-Liss, Inc. [source] Modelling blowing snow redistribution to prairie wetlandsHYDROLOGICAL PROCESSES, Issue 18 2009X. Fang Abstract Blowing snow transports and sublimates a substantial portion of the seasonal snowfall in the prairies of western Canada. Snow redistribution is an important feature of prairie hydrology as deep snowdrifts provide a source of meltwater to replenish ponds and generate streamflow in this dry region. The spatial distribution of snow water equivalent in the spring is therefore of great interest. A test of the distributed and aggregated modelling strategies for blowing snow transport and sublimation was conducted at the St. Denis National Wildlife Area in the rolling, internally drained prairie pothole region east of Saskatoon, Saskatchewan, Canada. A LiDAR-based DEM and aerial photograph-based vegetation cover map were available for this region. A coupled complex windflow and blowing snow model was run with 262,144 6 m × 6 m grid cells to produce spatially distributed estimates of seasonal blowing snow transport and sublimation. The calculation was then aggregated to seven landscape units that represented the major influences of surface roughness, topography and fetch on blowing snow transport and sublimation. Both the distributed and aggregated simulations predicted similar end-of-winter snow water equivalent with substantial redistribution of blowing snow from exposed sparsely vegetated sites across topographic drainage divides to the densely vegetated pothole wetlands. Both simulations also agreed well with snow survey observations. While the distributed calculations provide a fascinating and detailed visual image of the interaction of complex landscapes and blowing snow redistribution and sublimation, it is clear that blowing snow transport and sublimation calculations can be successfully aggregated to the spatial scale of the major landscape units in this environment. This means that meso and macroscale hydrological models can represent blowing snow redistribution successfully in the prairies. Copyright © 2009 John Wiley & Sons, Ltd. [source] Matching network design using non-Foster impedancesINTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 2 2006*Article first published online: 8 FEB 200, Stephen E. Sussman-Fort Abstract Non-Foster synthesis bypasses the gain-bandwidth limitations of conventional LC matching and achieves superior broadband performance by employing negative circuit elements, which are realized via negative impedance converters. The idea is to construct a negative-image model of an antenna, which cancels the antenna's parasitic reactance and transforms its frequency-dependent radiation resistance to a constant value. Successful implementation of negative-image modeling requires the realization of stable, low-loss negative elements. After a discussion of the basic ideas of non-Foster matching, we present experimental results for broadband, stable, high- Q, grounded negative capacitance. Next, in the first experimental confirmation of non-Foster impedance matching for signal reception, we use a floating negative capacitor to cancel a substantial portion of the reactance of a 6-in. monopole antenna. Over 20,110 MHz, the signal-to-noise ratio improved by up to 6 dB as compared to the same antenna with no matching, or to a lossy-matched blade antenna of twice the size. © 2006 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006. [source] Do worker absences affect productivity?INTERNATIONAL LABOUR REVIEW, Issue 1 2008The case of teachers Abstract. This article studies the impact of teacher absences on education. Using data spanning three academic years about 285 teachers and 8,631 predominantly economically disadvantaged students from a United States urban school district, it tests assumptions that a substantial portion of teachers' absences is discretionary and that these absences reduce productivity , students' mathematics scores. Since absent teachers are typically replaced by less qualified substitutes, instructional intensity and consistency may decline: ten days of teacher absence reduce students' achievement score by about 3.3 per cent of a standard deviation , enough to lower some students' designation in the state proficiency system and, thus, their motivation to succeed. [source] The Accession of the UK to the EC: A Welfare AnalysisJCMS: JOURNAL OF COMMON MARKET STUDIES, Issue 3 2002Michael Gasiorek This article provides a decomposition of the welfare impact on the UK arising from the changes in manufacturing trade consequent upon joining the EC. The methodology employed is that of computable general equilibrium (CGE) modelling, where the underlying model is based on trade under imperfect competition with firms producing under conditions of increasing returns to scale. CGE models can be seen as providing numerical illustrations of theory, or as empirical tools providing estimates of policies. A second aim of this article is then to asses the extent to which CGE models can be used as serious tools of policy analysis. We examine this by assessing the success of the model in replicating counterfactual outcomes. The results indicate (i) that the model does reasonably well in replicating complex reality and that such models can be empirically useful; (ii) that a substantial portion of the welfare impact is attributed to distortions associated with imperfect competition, and that the impact is potentially quite large. [source] Aggregate Earnings and Asset PricesJOURNAL OF ACCOUNTING RESEARCH, Issue 5 2009RAY BALL ABSTRACT A principal-components analysis demonstrates that common earnings factors explain a substantial portion of firm-level earnings variation, implying earnings shocks have substantial systematic components and are not almost fully diversifiable as prior literature has concluded. Furthermore, the principal components of earnings and returns are highly correlated, implying aggregate earnings risks and return risks are related. In contrast to previous studies, the correlation we report between the systematic components of earnings and returns is stable over time. We also show that the earnings factors are priced, in the sense that the sensitivities of securities' returns to the earnings factors explain a significant portion of the cross-sectional variation in returns, even controlling for return risk. This suggests earnings performance is an underlying source of priced risk. Our evidence that the information sets of returns and earnings are jointly determined implies cash flow risk and return risk are not fully separable, and raises the possibility that it is the common variation of earnings and returns that is priced. [source] Reproductive asynchrony in natural butterfly populations and its consequences for female matelessnessJOURNAL OF ANIMAL ECOLOGY, Issue 4 2008Justin M. Calabrese Summary 1Reproductive asynchrony, where individuals in a population are short-lived relative to the population-level reproductive period, has been identified recently as a theoretical mechanism of the Allee effect that could operate in diverse plant and insect species. The degree to which this effect impinges on the growth potential of natural populations is not yet well understood. 2Building on previous models of reproductive timing, we develop a general framework that allows a detailed, quantitative examination of the reproductive potential lost to asynchrony in small natural populations. 3Our framework includes a range of biologically plausible submodels that allow details of mating biology of different species to be incorporated into the basic reproductive timing model. 4We tailor the parameter estimation methods of the full model (basic model plus mating biology submodels) to take full advantage of data from detailed field studies of two species of Parnassius butterflies whose mating status may be assessed easily in the field. 5We demonstrate that for both species, a substantial portion of the female population (6·5,18·6%) is expected to die unmated. These analyses provide the first direct, quantitative evidence of female reproductive failure due to asynchrony in small natural populations, and suggest that reproductive asynchrony exerts a strong and largely unappreciated influence on the population dynamics of these butterflies and other species with similarly asynchronous reproductive phenology. [source] Conundrums in mixed woody,herbaceous plant systemsJOURNAL OF BIOGEOGRAPHY, Issue 11 2003Joanna I. House Abstract Aims To identify approaches to improve our understanding of, and predictive capability for, mixed tree,grass systems. Elucidation of the interactions, dynamics and determinants, and identification of robust generalizations that can be broadly applied to tree,grass systems would benefit ecological theory, modelling and land management. Methods A series of workshops brought together scientific expertise to review theory, data availability, modelling approaches and key questions. Location Ecosystems characterized by mixtures of herbaceous and woody plant life-forms, often termed ,savannas', range from open grasslands with few woody plants, to woodlands or forests with a grass layer. These ecosystems represent a substantial portion of the terrestrial biosphere, an important wildlife habitat, and a major resource for provision of livestock, fuel wood and other products. Results Although many concepts and principles developed for grassland and forest systems are relevant to these dual life-form communities, the novel, complex, nonlinear behaviour of mixed tree,grass systems cannot be accounted for by simply studying or modelling woody and herbaceous components independently. A more robust understanding requires addressing three fundamental conundrums: (1) The ,treeness' conundrum. What controls the relative abundance of woody and herbaceous plants for a given set of conditions at given site? (2) The coexistence conundrum. How do the life-forms interact with each other? Is a given woody,herbaceous ratio dynamically stable and persistent under a particular set of conditions? (3) The net primary productivity (NPP) conundrum. How does NPP of the woody vegetation, the herbaceous vegetation, and the total ecosystem (woody + herbaceous) change with changes in the tree,grass ratio? Tests of the theory and conceptual models of determinants of mixed woody,herbaceous systems have been largely site- or region-specific and have seldom been broadly or quantitatively evaluated. Cross-site syntheses based on data and modelling are required to address the conundrums and identify emerging patterns, yet, there are very few data sets for which either biomass or NPP have been quantified for both the woody and the herbaceous components of tree,grass systems. Furthermore, there are few cross-site comparisons spanning the diverse array of woody,herbaceous mixtures. Hence, initial synthesis studies should focus on compiling and standardizing a global data base which could be (1) explored to ascertain if robust generalizations and consistent patterns exist; and (2) used to evaluate the performance of savanna simulation models over a range of woody,herbaceous mixtures. Savanna structure and productivity are the result of complex and dynamic interactions between climate, soils and disturbances, notably fire and herbivory. Such factors are difficult to isolate or experimentally manipulate in order to evaluate their impacts at spatial and temporal scales appropriate for assessing ecosystem dynamics. These factors can, however, be evaluated with simulation models. Existing savanna models vary markedly with respect to their conceptual approach, their data requirements and the extent to which they incorporate mechanistic processes. Model intercomparisons can elucidate those approaches most suitable for various research questions and management applications. Conclusion Theoretical and conceptual advances could be achieved by considering a broad continuum of grass,shrub,tree combinations using data meta-analysis techniques and modelling. [source] Fruit and fibre: the nutritional value of figs for a small tropical ruminant, the blue duiker (Cephalophus monticola)AFRICAN JOURNAL OF ECOLOGY, Issue 4 2009Erin L. Kendrick Abstract Tropical forests throughout the world are home to a guild of small ruminants that consume fruit as a substantial portion of their diet. Because the rumen is relatively inefficient at digesting nonstructural carbohydrates and only slowly digests cellulose, the feeding adaptations of frugivorous ruminants are enigmatic. We examined the nutritional value of wild figs to blue duikers, one of the smallest and most frugivorous ruminants, through chemical analyses and a series of digestion trials with six species of wild African figs. These figs were high in fat, protein, cell wall, lignin and Ca : P ratios, low in sugar and starch, and high in unextractable, fibre-bound tannins when compared with many other fruits. The fibre-bound tannins and protein caused protein digestibility and nitrogen balance to be consistently low or negative. The high fibre content of the figs allowed duikers to only digest 30,60% of energy contained in the figs. However, duikers were able to consume enough digestible energy to maintain body mass during 4-day trials. Therefore, a ruminant digestive system is beneficial to mammals eating high fibre, high-tannin tropical fruit like figs, especially if the mammal is small enough to harvest a sufficient amount to meet its daily energy requirements and has adaptations for reducing the effects of tannins on protein digestibility. Résumé Les forêts tropicales du monde entier abritent toute une faune de petits ruminants dont les fruits constituent une part non négligeable de l'alimentation. Comme le rumen est relativement peu efficace pour digérer les hydrates de carbone non structuraux et ne digère que lentement la cellulose, les adaptations alimentaires des ruminants frugivores sont encore énigmatiques. Nous avons examiné la valeur nutritionnelle des figues sauvages pour le céphalophe bleu, un des ruminants les plus petits et parmi les plus frugivores, au moyen d'analyses chimiques et d'une série d'essais de digestion avec six espèces de figues sauvages africaines. Ces figues étaient riches en graisses, en protéines, en parois cellulaires, en lignine, et leur rapport Ca/P était élevé; elles avaient un contenu faible en sucre et en amidon, et beaucoup de tanins impossibles à extraire, liés aux fibres, comparés à de nombreux autres fruits. Les tanins liés aux fibres et les protéines faisaient que la digestibilité des protéines et l'équilibre azotéétaient en permanence faibles ou négatifs. Le contenu en fibres élevé des figues ne permettait aux céphalophes de digérer que 30 à 60% de l'énergie contenue dans les figues. Cependant, pendant les quatre jours du test, les céphalophes ont pu consommer suffisamment d'énergie digestible pour conserver leur masse corporelle. C'est pourquoi le système digestif des ruminants est bénéfique pour les mammifères qui consomment des fruits tropicaux riches en fibres et en tanins, comme les figues, spécialement si le mammifère est assez petit pour pouvoir en trouver une quantité suffisante pour répondre à ses besoins quotidiens en énergie, et qu'il possède des adaptations qui lui permettent de réduire les effets des tanins sur la digestibilité des protéines. [source] Meta-analysis of the effect of scaling and root planing, surgical treatment and antibiotic therapies on periodontal probing depth and attachment lossJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 11 2002Hsin-Chia Hung Abstract Objective: This paper reports a meta-analysis of studies that have investigated the effect of scaling and root planing on periodontal probing depth and attachment loss. Material and methods: The criteria used for inclusion of studies were as follows: root planing and scaling alone was one of the primary treatment arms; patients or quadrants of each patient were randomly assigned to study groups; 80% of patients enrolled were included in first year follow-up examinations; periodontal probing depth and attachment loss were reported in mm; the sample size of each study and substudy was reported. Sample size was used to weight the relative contribution of each study since standard errors were not reported by many studies and sample size is highly correlated with standard error and therefore statistically able to explain a substantial portion of the standard error on studies that use similar measures. Results: The meta-analysis results show that periodontal probing depth and gain of attachment level do not improve significantly following root planing and scaling for patients with shallow initial periodontal probing depths. However, there was about a 1-mm reduction for medium initial periodontal probing depths and a 2-mm reduction for deep initial periodontal probing depths. Similarly, there was about a 0.50-mm gain in attachment for medium initial periodontal probing depth measurements and slightly more than a l-mm gain in attachment for deep initial periodontal probing depth measurements. Surgical therapy for patients with deep initial probing depths showed better results than scaling and root planing in reducing probing depths. When patients were followed up over 3 years or more, these differences were reduced to less than 0.4 mm. Antibiotic therapy showed similar results to scaling and root planing. However, a consistent improvement in periodontal probing depth and gain of attachment is demonstrated when local antibiotic therapy is combined with root planing and scaling. Zusammenfassung Metaanalyse des Effekts von Scaling und Wurzelglätten, chirurgischer Behandlung und Antibiotikatherapien auf parodontale Sondiertiefe und Attachment-Verlust Zielsetzung: Der vorliegende Artikel beschreibt eine Metaanalyse von Studien, in denen die Wirkung von Scaling und Wurzelglätten auf parodontale Sondiertiefe und Attachment-Verlust untersucht wurden. Material und Methodik: Die Kriterien für die Aufnahme in die Studie waren wie folgt: 1) Wurzelglätten und Scaling allein war einer der primären Behandlungsverfahren; 2) Patienten oder Quadranten einzelner Patienten wurden auf Studiengruppen zufallsverteilt; 3) 80% der aufgenommenen Patienten waren in den Follow-up-Untersuchungen nach einem Jahr eingeschlossen; 4) parodontale Sondiertiefe und Attachment-Verlust wurden in mm berichtet; und 5) der Probenumfang jeder einzelnen Studie und Unterstudie wurde berichtet. Der Probenumfang wurde zur Gewichtung des relativen Beitrages jeder einzelnen Studie herangezogen, da von vielen Studien keine Standardabweichungen berichtet wurden und der Probenumfang mit der Standardabweichung stark korreliert ist. Daher lässt sich auf dem Weg über den Probenumfang ein wesentlicher Teil der Standardabweichung bei Studien mit ähnlichen Messparametern statistisch erklären. Ergebnisse: Die Ergebnisse der Metaanalyse zeigten, dass die parodontale Sondiertiefe und die Zunahme des Attachment-Niveaus nach Scaling und Wurzelglätten bei Patienten mit ursprünglich geringen Sondiertiefen keine signifikanten Verbesserungen liefern. Bei ursprünglich mittleren parodontalen Sondiertiefen konnte jedoch eine Reduktion von 1 mm, bei ursprünglich tiefen parodontalen Sondiertiefen eine Reduktion von 2 mm beobachtet werden. Dementsprechend wurde eine Zunahme des Attachment-Niveaus bei ursprünglich mittleren parodontalen Sondiertiefen von 0,5 mm eine sowie eine Zunahme von etwas mehr als 1 mm bei ursprünglich tiefen parodontalen Sondiertiefen verzeichnet. Die chirurgische Behandlung bei Patienten mit ursprünglich beträchtlicher Sondiertiefe lieferte bei der Reduktion der Sondiertiefe bessere Ergebnisse als Scaling und Wurzelglätten. Wenn sich Patienten über 3 Jahre oder länger einem Follow-up unterzogen, liessen sich diese Differenzen auf unter 0,4 mm reduzieren. Darüber hinaus kann jedoch eine konsistente Verbesserung der parodontalen Sondiertiefe und Zunahme des Attachment-Niveaus erreicht werden, wenn eine lokale Antibiotikatherapie mit Scaling und Wurzelglätten kombiniert wird. Résumé Méta-analyse de l'influence du détartrage et du surfaçage radiculaire, du traitement chirurgical et des traitements antibiotiques sur la profondeur de poche au sondage et la perte d'attache But: Ce rapport présente une méta-analyse des études qui ont porté sur l'influence du détartrage et du surfaçage radiculaire sur la profondeur de poche au sondage et la perte d'attache. Matériaux et méthodes: Les critères d'inclusion dans les études étaient les suivants: 1) le détartrage et le surfaçage radiculaire constituaient l'un des premiers moyens de traitement utilisés; 2) les patients ou les quadrants de chaque patient ont été répartis dans les groupes d'étude de façon aléatoire; 3) 80% des patients enrôlés ont fait l'objet d'examens de suivi durant un an; 4) la profondeur de poche au sondage et la perte d'attache ont été mesurés en mm; 5) la taille de l'échantillon a été relevée pour chaque étude et sous-étude. La taille de l'échantillon a été utilisée pour évaluer la contribution relative de chaque étude. En effet, de nombreuses études ne mentionnaient pas les erreurs standard, alors qu'il existe une corrélation étroite entre la taille de l'échantillon et l'erreur standard et qu'elle permet donc d'expliquer statistiquement une part substantielle de l'erreur standard dans les études qui se basent sur des mesures similaires. Résultats: Les résultats de la méta-analyse montrent que la profondeur de poche au sondage et le gain d'attache ne s'améliorent pas de façon significative suite au détartrage et surfaçage radiculaire chez les patients dont les profondeurs de poche au sondage initiales étaient faibles. Il y avait toutefois une réduction d'environ 1 mm des profondeurs de poche au sondage initiales moyennes, et une réduction de 2 mm des profondeurs de poche au sondage initiales élevées. De façon similaire, on a observé un gain d'attache d'environ 0,50 mm pour les mesures des profondeurs de poche au sondage initiales moyennes et un gain d'attache légèrement supérieur à 1 mm pour les mesures des profondeurs de poche au sondage initiales élevées. Chez les patients à profondeur de poche au sondage initiale élevée, le traitement par chirurgie s'est avéré plus efficace que le détartrage et le surfaçage radiculaire pour réduire la profondeur au sondage. Lorsque les patients faisaient l'objet d'un suivi durant trois ans ou plus, ces différences s'abaissaient jusqu'à moins de 0,4 mm. Le traitement antibiotique a donné des résultats similaires à ceux obtenus par détartrage et surfaçage radiculaire. Une amélioration régulière de la profondeur de poche au sondage et du gain d'attache a toutefois été observée lorsque le traitement antibiotique local est combiné au détartrage et surfaçage radiculaire. [source] Is your IT structure obsolete?JOURNAL OF CORPORATE ACCOUNTING & FINANCE, Issue 5 2008Timothy Iijima Today's big companies rely on their IT systems and networks in a huge way,and that concentrates a substantial portion of a company's risk in the IT organization. Virtually no activity within a company can now happen without major help from IT. So IT organization structure can no longer function as an afterthought,because a poorly performing IT organization creates unacceptable risk for the company. The author takes a close look at today's critical functions and roles for IT, the organization structures used, and why older IT organization models are no longer adequate. Is your firm's IT organization obsolete in today's world? © 2008 Wiley Periodicals, Inc. [source] Satellite DNA and chromosomes in Neotropical fishes: methods, applications and perspectivesJOURNAL OF FISH BIOLOGY, Issue 5 2010M. R. Vicari Constitutive heterochromatin represents a substantial portion of the eukaryote genome, and it is mainly composed of tandemly repeated DNA sequences, such as satellite DNAs, which are also enriched by other dispersed repeated elements, including transposons. Studies on the organization, structure, composition and in situ localization of satellite DNAs have led to consistent advances in the understanding of the genome evolution of species, with a particular focus on heterochromatic domains, the diversification of heteromorphic sex chromosomes and the origin and maintenance of B chromosomes. Satellite DNAs can be chromosome specific or species specific, or they can characterize different species from a genus, family or even representatives of a given order. In some cases, the presence of these repeated elements in members of a single clade has enabled inferences of a phylogenetic nature. Genomic DNA restriction, using specific enzymes, is the most frequently used method for isolating satellite DNAs. Recent methods such as C0t,1 DNA and chromosome microdissection, however, have proven to be efficient alternatives for the study of this class of DNA. Neotropical ichthyofauna is extremely rich and diverse enabling multiple approaches with regard to the differentiation and evolution of the genome. Genome components of some species and genera have been isolated, mapped and correlated with possible functions and structures of the chromosomes. The 5SHindIII-DNA satellite DNA, which is specific to Hoplias malabaricus of the Erythrinidae family, has an exclusively centromeric location. The As51 satellite DNA, which is closely correlated with the genome diversification of some species from the genus Astyanax, has also been used to infer relationships between species. In the Prochilodontidae family, two repetitive DNA sequences were mapped on the chromosomes, and the SATH 1 satellite DNA is associated with the origin of heterochromatic B chromosomes in Prochilodus lineatus. Among species of the genus Characidium and the Parodontidae family, amplifications of satellite DNAs have demonstrated that these sequences are related to the differentiation of heteromorphic sex chromosomes. The possible elimination of satellite DNA units could explain the genome compaction that occurs among some species of Neotropical Tetraodontiformes. These topics are discussed in the present review, showing the importance of satellite DNA analysis in the differentiation and karyotype evolution of Actinopterygii. [source] Pharmacokinetic aspects of biotechnology productsJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 9 2004Lisa Tang Abstract In recent years, biotechnologically derived peptide and protein-based drugs have developed into mainstream therapeutic agents. Peptide and protein drugs now constitute a substantial portion of the compounds under preclinical and clinical development in the global pharmaceutical industry. Pharmacokinetic and exposure/response evaluations for peptide and protein therapeutics are frequently complicated by their similarity to endogenous peptides and proteins as well as protein nutrients. The first challenge frequently comes from a lack of sophistication in various analytical techniques for the quantification of peptide and protein drugs in biological matrices. However, advancements in bioassays and immunoassays,along with a newer generation of mass spectrometry-based techniques,can often provide capabilities for both efficient and reliable detection. Selection of the most appropriate route of administration for biotech drugs requires comprehensive knowledge of their absorption characteristics beyond physicochemical properties, including chemical and metabolic stability at the absorption site, immunoreactivity, passage through biomembranes, and active uptake and exsorption processes. Various distribution properties dictate whether peptide and protein therapeutics can reach optimum target site exposure to exert the intended pharmacological response. This poses a potential problem, especially for large protein drugs, with their typically limited distribution space. Binding phenomena and receptor-mediated cellular uptake may further complicate this issue. Elimination processes,a critical determinant for the drug's systemic exposure,may follow a combination of numerous pathways, including renal and hepatic metabolism routes as well as generalized proteolysis and receptor-mediated endocytosis. Pharmacokinetic/pharmacodynamic (PK/PD) correlations for peptide and protein-based drugs are frequently convoluted by their close interaction with endogenous substances and physiologic regulatory feedback mechanisms. Extensive use of pharmacokinetic and exposure/response concepts in all phases of drug development has in the past been identified as a crucial factor for the success of a scientifically driven, evidence-based, and thus accelerated drug development process. Thus, PK/PD concepts are likely to continue and expand their role as a fundamental factor in the successful development of biotechnologically derived drug products in the future. © 2004 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 93:2184,2204, 2004 [source] Alternate delivery route for amifostine as a radio-/chemo-protecting agentJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 7 2008Natalie P. Praetorius Amifostine (ethiofos, WR-2721) is an organic thiophosphate prodrug that serves as an antineoplastic adjunct and cytoprotective agent useful in cancer chemotherapy and radiotherapy. The selective protection of certain tissues of the body is believed to be due to higher alkaline phosphatase activity, higher pH and vascular permeation of normal tissues. Amifostine is conventionally administered intravenously before chemotherapy or radiotherapy. It is approved by the Food and Drug Administration (FDA) to reduce cumulative renal toxicity associated with repeated administration of cisplatin in patients with advanced ovarian cancer. It was originally indicated to reduce the cumulative renal toxicity from cisplatin in non-small cell lung cancer although this indication was withdrawn in 2005. Amifostine is also FDA approved for patients with head and neck cancer to reduce the incidence of moderate to severe xerostomia in patients who are undergoing postoperative radiation treatment where the radiation port includes a substantial portion of the parotid glands. The potential of amifostine as a cytoprotective agent is unlikely to be fully realized if the method of administration is restricted to intravenous administration. Attempts have been made to develop non-invasive methods of delivery such as transdermal patches, pulmonary inhalers, and oral sustained-release microspheres. It is the goal of this article to explore non-intravenous routes of administration associated with better efficacy of the drug. This review will primarily focus on the variety of more recently studied (2002 and later) alternative modes for amifostine administration, including subcutaneous, intrarectal and oral routes. [source] Transnational Corporations and Repression of Political Rights and Civil Liberties: An Empirical AnalysisKYKLOS INTERNATIONAL REVIEW OF SOCIAL SCIENCES, Issue 1 2004Matthias Busse Summary Transnational Corporations are often accused by non-governmental organisations of ignoring fundamental democratic rights, such as civil liberties and political rights, in the countries of their investments. This paper attempts to explore empirically the complex relationship between foreign investment and democracy in a systematic way, using different econometric techniques. In contrast to the public discussion over recent years and the view held by non-governmental organisations, the results show that enhanced democratic rights are associated with higher foreign investment in the 1990s. Interestingly, this positive link does not hold for the 1970s and 1980s, when a substantial portion of foreign investment went to countries with repressive governments. [source] Bridging the Gap Between Genomics and EducationMIND, BRAIN, AND EDUCATION, Issue 4 2007Stephen A. Petrill ABSTRACT, Despite several decades of research suggesting the importance of both genetic and environmental factors, these findings are not well integrated into the larger educational literature. Following a discussion of quantitative and molecular genetic methods, this article reviews behavioral genetic findings related to cognitive and academic skills. This literature suggests that (a) the relative importance of genes and environments varies developmentally; (b) genetics, and to a lesser extend the environment, account for a substantial portion of the covariance within and across academic domains; and (c) some forms of disability are qualitatively different from the population, whereas others constitute the lower end of a continuum of ability. Following a discussion of the strengths and limitations of current behavioral genetic research and intervention research, we then discuss the ways in which understanding gene,environment interplay can be used to develop better definitions of learning impairment and better explain the substantial variability in response to intervention. [source] Word Searches in NNS,NS Interaction: Opportunities for Language Learning?MODERN LANGUAGE JOURNAL, Issue 4 2003Catherine E. Brouwer A substantial portion of second language acquisition research focuses on interactional practices in which nonnative speakers (NNSs) engage. From various theoretical viewpoints, it is assumed that certain types of interactional practices, specifically those in which participants focus on linguistic form, may promote language learning. The question of whether, and under which conditions, such sequences can be seen as providing the NNS with language learning opportunities, is considered in a purely data-driven way, applying conversation analysis (CA) as a method. The article considers one specific type of interactional practice, "word search" sequences, and opportunities for language learning that they may provide for NNSs on the basis of naturally occurring interactions between native speakers of Danish and Dutch speakers of Danish. It is argued that in order to distinguish between "language learning opportunities" and other types of interactional practices, the researcher needs to analyze the data in detail. [source] Uptake and translocation of carpropamid in rice (Oryza sativa L)PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 3 2001Rashmi Rohilla Abstract Translocation of the antiblast compound, carpropamid, was investigated in rice using [14C]carpropamid. When applied to the seed, carpropamid was not only readily absorbed but was translocated to different parts of the seedlings emerging from treated seeds. A substantial portion of fungicide appeared to be exuded onto the leaf surface. In 21-day-old plants grown from [14C]carpropamid-treated seeds, 27.2% of the radioactivity isolated from leaves was present on the surface of lamina. This exuded fraction is probably responsible for its action as a fungal anti-penetrant compound. Following 30-min root dipping of 14-day-old seedlings, carpropamid was rapidly absorbed and translocated throughout the seedling. Its intra-laminar distribution was uniform as determined by autoradiography. Only a small fraction (<2%) of fungicide applied to the foliage was translocated beyond the site of application within the treated leaf. Translocation was primarily apoplastic. Approximately 54% of the radioactivity recovered from leaves was in the form of carpropamid. At least seven radiolabelled metabolic products were observed by TLC. Only 8.3% of radioactivity applied through the seeds could be recovered from 21-day-old seedlings. © 2001 Society of Chemical Industry [source] The descent of tropospheric air into the stratosphereTHE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 562 2000M. N. Juckes Abstract Since the stratosphere lies above the troposphere, naive expectation would associate mass transfer from the latter into the former with ascent. This note shows that, in the context of the mass circulation associated with large scales in mid latitudes, the transfer into the stratosphere can actually be associated with descent relative to isentropes. The diabatic effects which accompany the transfer of air from the troposphere to the stratosphere are such as to give the air a downward motion, but, the motion of the tropopause is faster so that the descending air is overtaken by the tropopause and transferred into the stratosphere. Combined with the conclusions of an earlier study, these results suggest that the dryness of a substantial portion of the air in the lowermost extra-tropical stratosphere is caused by its passage through extremely low tropopause temperatures associated with transient mid-latitude high-pressure systems. [source] Long-term effective population size of three endangered Colorado River fishesANIMAL CONSERVATION, Issue 2 2002Daniel Garrigan The extant genetic variation of a population is the legacy of both long-term and recent population dynamics. Most practical methods for estimating effective population size are only able to detect recent effects on genetic variation and do not account for long-term fluctuations in species abundance. The utility of a maximum likelihood estimator of long-term effective population size based upon the coalescent theory of gene genealogies is examined for three endangered Colorado River fishes: humpback chub (Gila cypha), bonytail chub (Gila elegans) and razorback sucker (Xyrauchen texanus). Extant mitochondrial DNA (mtDNA) variation in humpback chub suggests this species has retained its historical equilibrium genetic variation despite recent declines in abundance. The mtDNA variation in razorback suckers indicates the population was quite large and expanding prior to recent declines and that rare alleles still survive in the remnant populations. The remaining mtDNA variation in bonytail chub indicates that dramatic, recent declines may have already obliterated a substantial portion of any historical variation. The results from long-term effective population size analyses are consistent with known natural history and illustrate the utility of the analysis for endangered species management. [source] A biocatalyst for the removal of sulfite from alcoholic beveragesBIOTECHNOLOGY & BIOENGINEERING, Issue 1 2005Sung-Chyr Lin Abstract The presence of sulfites in alcoholic beverages, particularly in wines, can cause allergic responses with symptoms ranging from mild gastrointestinal problems to life threatening anaphylactic shock in a substantial portion of the population. We have developed a simple and inexpensive biocatalytic method that employs wheatgrass (Triticum aestivum) chloroplasts for the efficient oxidation of sulfites in wines to innocuous sulfates. A sufficiently high rate of sulfite oxidation was obtained in the presence of ethanol at concentrations commonly found in most wines. Crude chloroplast preparations at a concentration as low as 5 mg/mL were capable of reducing sulfite in commercial white wines from 150 ppm to under 7.5 ppm within 3 hours. A 93% removal of sulfite in commercial red wines was observed with 1 mg/mL chloroplasts within 45 min. Optimal sulfite removal efficiency was observed at pH 8.5 and was promoted by illumination, indicating the participation of light-induced photosynthetic electron transport processes in sulfite oxidation. Overall, this work indicates that biocatalytic oxidation using wheatgrass chloroplasts can be employed to remove sulfites from beverages prior to consumption. © 2004 Wiley Periodicals, Inc. [source] Clinical nurse specialist care managers' time commitments in a disease-management program for bipolar disorderBIPOLAR DISORDERS, Issue 6 2004Henry A Glick Objectives:, As part of a cost-effectiveness analysis for Department of Veterans Affairs Cooperative Studies Program #430, ,Reducing the Efficacy-Effectiveness Gap in Bipolar Disorder,' we conducted a time and motion study to quantify the time psychiatric clinical nurse specialist (CNS) care managers spent providing care for patients. Methods:, Clinical nurse specialist care managers completed activity logs in which they recorded time spent implementing the Bipolar Disorders Program (BDP) during a 1-week period in spring, summer, fall and winter over a 1-year period when caseloads were at steady state. Mean service time was estimated by use of univariate analysis of means and by multivariable regression analysis. Results:, On average CNS care managers spent 40% of their clinical time in activities that typically are reimbursed (e.g. clinic visits) and spent the remaining 60% of their time in activities that are typically unreimbursed. Total clinic time increased as the number of visits per day increased; however, this increase got smaller with each additional visit per day. Conclusions:, As with other chronic illness management programs, CNS care managers expend a substantial portion of their clinical effort for the BDP in activities that are typically unreimbursed. Their activities have a fixed component per day as well as a component that systematically varies with the number of visits per day. These findings should be considered when costing out and disseminating psychiatric and other medical chronic illness management programs. [source] Neurocognitive function in patients with small cell lung cancer,CANCER, Issue 3 2008Effect of prophylactic cranial irradiation Abstract BACKGROUND. The use of prophylactic cranial irradiation (PCI) in patients with small cell lung cancer (SCLC) has been tempered by fears of detrimental effects on cognitive function. Neuropsychologic testing was prospectively conducted before and after PCI to evaluate its effects on cognitive function in patients with SCLC. METHODS. Ninety-six patients who completely or partially responded to initial therapy underwent formal neurocognitive testing before PCI. Three patients who had central nervous system metastasis were excluded. Of the remaining patients, 69 received PCI (mean dose, 25 grays [Gy] in 10 fractions). Repeat testing was performed on 37 patients (median follow-up, 23 months; range, 6,120 months). RESULTS. Baseline impairment was defined as ,1.5 standard deviations below the normative mean. Before undergoing PCI, 47% of patients had evidence of impaired cognitive function. After PCI, univariate analysis revealed significant transient declines in executive function (pre-PCI mean, 15.6 ± 11.5; post-PCI, 27.1 ± 17.6 [P = .008]) and language (pre-PCI mean, 33.8 ± 9.9; post-PCI, 31.0 ± 9.0 [P = .049]) at early timepoints. Controlling for noncentral nervous system disease progression the deficit in executive function was no longer significant. Moreover, these deficits were not sustained, and significant improvements in language and motor coordination were recorded. On multivariate analysis, no significant differences before and after PCI were found. CONCLUSIONS. Neurocognitive testing demonstrated that a substantial portion of patients with SCLC had impaired brain functioning at baseline. Persistent declines in cognitive function were not observed after cranial irradiation. These data do not favor the omission of PCI on the basis of fears of neurotoxic effects. Cancer 2008. © 2007 American Cancer Society. [source] | |||||||||||||||||||||||||||||||||||||||||||