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Small Effects (small + effects)
Selected AbstractsLimbal and Bulbar Hyperaemia in Normal EyesOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 1 2008Heiko Pult Abstract Purpose:, To investigate the appearance of limbal and bulbar hyperaemia in normal eyes, their relationship and the inter-observer agreement of clinical grading. Methods:, The right eyes of 120 healthy, non-contact lens-wearing subjects (m = 57, f = 63, median age = 45 years, range 18,77 years) were examined by two trained observers. Limbal and bulbar hyperaemia were scored using the Cornea and Contact Lens Research Unit (CCLRU) redness grading scales interpolated into 0.1 increments. Redness of four quadrants, and overall, were assessed, and quadrant-average redness was calculated. Inter-observer agreement was assessed at the start and end of the study (20 subjects each). Results:, For limbal redness, the overall (1.62 ± 0.46) (mean units ± S.D.) was not significantly different from the quadrant-average (1.61 ± 0.40) score. For bulbar redness, the overall (2.02 ± 0.49) was higher than the quadrant-average (1.82 ± 0.39) score (p < 0.0001). Significant correlations were found between bulbar and limbal quadrants (Pearson: r , 0.43, p < 0.0001). Significant differences in redness were found between quadrants (p < 0.0001), with nasal and temporal redder than superior and inferior quadrants. Small effects of age and gender were found for limbal redness. The inter-observer 95% limits of agreement were similar at the start and end of the study. They were larger for overall (0.57) compared with quadrant-average (0.28) redness. Conclusions:, For similar populations, a limbal redness above 2.5 or a bulbar redness above 2.6 (quadrant-average) or 3.0 (overall) may be considered abnormal. Limbal and bulbar redness were correlated. Quadrant-average scores are recommended instead of overall scores, as inter-observer agreement was better. [source] From age correction to genome-wide associationACTA PSYCHIATRICA SCANDINAVICA, Issue 5 2009S. Cohen-Woods Objective:, Eric Strömgren was one of the pioneers of psychiatric genetics and family studies. There has now been an explosion of interest in this field and research progress, including linkage and association studies, whole genome genotyping, copy number variants and epigenetics is reviewed here. Method:, An overview of this area of psychiatric research is presented and discussed based on the relevant literature aiming at giving a recent status of the progress. Results:, Broadly speaking linkage and association are complementary approaches used to locate genes contributing to the genetic aetiology of psychopathology. Linkage can be detected over comparatively large distances, however power is problematic when searching for quantitative trait loci with small effect sizes. In contrast, association studies can detect small effects but only over very small distances. Therefore, while several genome-wide linkage studies in psychiatric disorders have been performed, the majority of association studies have investigated specific functional candidate genes. Conclusion:, Due to very recent technological advancements, genome-wide association studies have now become possible and have identified some completely novel susceptibility loci. Other recent advances include the discovery of epigenetic phenomena and copy number variants. [source] Adaptation, migration or extirpation: climate change outcomes for tree populationsEVOLUTIONARY APPLICATIONS (ELECTRONIC), Issue 1 2008Sally N. Aitken Abstract Species distribution models predict a wholesale redistribution of trees in the next century, yet migratory responses necessary to spatially track climates far exceed maximum post-glacial rates. The extent to which populations will adapt will depend upon phenotypic variation, strength of selection, fecundity, interspecific competition, and biotic interactions. Populations of temperate and boreal trees show moderate to strong clines in phenology and growth along temperature gradients, indicating substantial local adaptation. Traits involved in local adaptation appear to be the product of small effects of many genes, and the resulting genotypic redundancy combined with high fecundity may facilitate rapid local adaptation despite high gene flow. Gene flow with preadapted alleles from warmer climates may promote adaptation and migration at the leading edge, while populations at the rear will likely face extirpation. Widespread species with large populations and high fecundity are likely to persist and adapt, but will likely suffer adaptational lag for a few generations. As all tree species will be suffering lags, interspecific competition may weaken, facilitating persistence under suboptimal conditions. Species with small populations, fragmented ranges, low fecundity, or suffering declines due to introduced insects or diseases should be candidates for facilitated migration. [source] A unified framework for transmission-disequilibrium test analysis of discrete and continuous traitsGENETIC EPIDEMIOLOGY, Issue 1 2002Ying Liu Abstract This paper presents a unified framework for transmission-disequilibrium tests for discrete and continuous traits. A conditional score test is derived that maximizes power to detect small effects for any exponential family distribution, which includes binary and normal distributions, and distributions that are skewed or have non-normal kurtosis. The specific distributional form need not be specified, and the method applies to sibships of arbitrary size. Formulas for the distribution of the test statistic are given for models including complex genetic effects (additive, dominant, and recessive gene action), covariates, multiple gene models including gene-gene interactions or heterogeneity, and gene-environment interactions. We develop refinements of our method for trait-based sampling designs and multiple siblings that can have dramatic effects on power. Genet. Epidemiol. 22:26,40, 2002. © 2002 Wiley-Liss, Inc. [source] Importance of changing CO2, temperature, precipitation, and ozone on carbon and water cycles of an upland-oak forest: incorporating experimental results into model simulationsGLOBAL CHANGE BIOLOGY, Issue 9 2005Paul J. Hanson Abstract Observed responses of upland-oak vegetation of the eastern deciduous hardwood forest to changing CO2, temperature, precipitation and tropospheric ozone (O3) were derived from field studies and interpreted with a stand-level model for an 11-year range of environmental variation upon which scenarios of future environmental change were imposed. Scenarios for the year 2100 included elevated [CO2] and [O3] (+385 ppm and +20 ppb, respectively), warming (+4°C), and increased winter precipitation (+20% November,March). Simulations were run with and without adjustments for experimentally observed physiological and biomass adjustments. Initial simplistic model runs for single-factor changes in CO2 and temperature predicted substantial increases (+191% or 508 g C m,2 yr,1) or decreases (,206% or ,549 g C m,2 yr,1), respectively, in mean annual net ecosystem carbon exchange (NEEa,266±23 g C m,2 yr,1 from 1993 to 2003). Conversely, single-factor changes in precipitation or O3 had comparatively small effects on NEEa (0% and ,35%, respectively). The combined influence of all four environmental changes yielded a 29% reduction in mean annual NEEa. These results suggested that future CO2 -induced enhancements of gross photosynthesis would be largely offset by temperature-induced increases in respiration, exacerbation of water deficits, and O3 -induced reductions in photosynthesis. However, when experimentally observed physiological adjustments were included in the simulations (e.g. acclimation of leaf respiration to warming), the combined influence of the year 2100 scenario resulted in a 20% increase in NEEa not a decrease. Consistent with the annual model's predictions, simulations with a forest succession model run for gradually changing conditions from 2000 to 2100 indicated an 11% increase in stand wood biomass in the future compared with current conditions. These model-based analyses identify critical areas of uncertainty for multivariate predictions of future ecosystem response, and underscore the importance of long term field experiments for the evaluation of acclimation and growth under complex environmental scenarios. [source] The Effect of Three-Tier Formulary Adoption on Medication Continuation and Spending among Elderly RetireesHEALTH SERVICES RESEARCH, Issue 5 2007Haiden A. Huskamp Objective. To assess the effect of three-tier formulary adoption on medication continuation and spending among elderly members of retiree health plans. Data Sources. Pharmacy claims and enrollment data on elderly members of four retiree plans that adopted a three-tier formulary over the period July 1999 through December 2002 and two comparison plans that maintained a two-tier formulary during this period. Study Design. We used a quasi-experimental design to compare the experience of enrollees in intervention and comparison plans. We used propensity score methods to match intervention and comparison users of each drug class and plan. We estimated repeated measures regression models for each class/plan combination for medication continuation and monthly plan, enrollee, and total spending. We estimated logit models of the probability of nonpersistent use, medication discontinuation, and medication changes. Data Collection/Extraction Methods. We used pharmacy claims to create person-level drug utilization and spending files for the year before and year after three-tier adoption. Principal Findings. Three-tier formulary adoption resulted in shifting of costs from plan to enrollee, with relatively small effects on medication continuation. Although implementation had little effect on continuation on average, a small minority of patients were more likely to have gaps in use and discontinue use relative to comparison patients. Conclusions. Moderate cost sharing increases from three-tier formulary adoption had little effect on medication continuation among elderly enrolled in retiree health plans with relatively generous drug coverage. [source] Tidal Barrages and BirdsIBIS, Issue 2006NIGEL A. CLARK This paper reviews the main effects that building tidal power barrages would have on the bird populations using Britain's estuaries. The changes in the tidal prism that would occur after a tidal power barrage is built are discussed in the context of their effect on the ecology of the estuary. Three main issues are discussed; the effect of changes in size and nature of the intertidal areas of the estuary, effects on saltmarshes, and the displacement of birds at closure. Recently, tidal stream technologies have been developed which are individually likely to have small effects on birds. However the cumulative effects of large scale tidal stream arrays need to be investigated. Finally, the effects of tidal barrages are put in the context of Britain's energy policy and the need to reduce greenhouse gas emissions. Should tidal power barrages be considered in the future, there will be a need for strategic assessments to be used to select sites that maximize the energy produced while minimizing the impacts on bird populations. [source] The distribution of QTL additive and dominance effects in porcine F2 crossesJOURNAL OF ANIMAL BREEDING AND GENETICS, Issue 3 2010J. Bennewitz Summary The present study used published quantitative trait loci (QTL) mapping data from three F2 crosses in pigs for 34 meat quality and carcass traits to derive the distribution of additive QTL effects as well as dominance coefficients. Dominance coefficients were calculated as the observed QTL dominance deviation divided by the absolute value of the observed QTL additive effect. The error variance of this ratio was approximated using the delta method. Mixtures of normal distributions (mixtures of normals) were fitted to the dominance coefficient using a modified EM-algorithm that considered the heterogeneous error variances of the data points. The results suggested clearly to fit one component which means that the dominance coefficients are normally distributed with an estimated mean (standard deviation) of 0.193 (0.312). For the additive effects mixtures of normals and a truncated exponential distribution were fitted. Two components were fitted by the mixtures of normals. The mixtures of normals did not predict enough QTL with small effects compared to the exponential distribution and to literature reports. The estimated rate parameter of the exponential distribution was 5.81 resulting in a mean effect of 0.172. [source] Rapamycin impairs trabecular bone acquisition from high-dose but not low-dose intermittent parathyroid hormone treatmentJOURNAL OF CELLULAR PHYSIOLOGY, Issue 3 2009P.J. Niziolek The osteo-anabolic effects of intermittent parathyroid hormone (PTH) treatment require insulin-like growth factor (IGF) signaling through the IGF-I receptor. A major downstream target of the IGF-I receptor (via Akt) is the mammalian target of rapamycin (mTOR), a kinase involved in protein synthesis. We investigated whether the bone-building effects of intermittent PTH require functional mTOR signaling. Mice were treated with daily PTH 1,34 (0, 10, 30, or 90,µg/kg) for 6 weeks in the presence or absence of rapamycin, a selective inhibitor of mTOR. We found that all PTH doses were effective in enhancing bone mass, whether rapamycin was present or not. Rapamycin had little to no effect on the anabolic response at low (10,µg) PTH doses, small effects in a minority of anabolic measures at moderate doses (30,µg), but the anabolic effects of high-dose PTH (90,µg) were consistently and significantly suppressed by rapamycin (,4,36% reduction). Serum levels of Trap5b, a marker of resorption, were significantly enhanced by rapamycin, but these effects were observed whether PTH was absent or present. Our data suggest that intermittent PTH, particularly at lower doses, is effective in building bone mass in the presence of rapamycin. However, the full anabolic effects of higher doses of PTH are significantly suppressed by rapamycin, suggesting that PTH might normally activate additional pathways (including mTOR) for its enhanced high-dose anabolic effects. Clinical doses of intermittent PTH could be an effective treatment for maintaining or increasing bone mass among patients taking rapamycin analogs for unrelated health issues. J. Cell. Physiol. 221: 579,585, 2009. © 2009 Wiley-Liss, Inc. [source] Aggressive periodontitis is likely influenced by a few small effect genesJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 6 2009Flavia M. De Carvalho Abstract Aim: To evaluate the inheritance mode of aggressive periodontitis in a collection of families with a similar geographic origin. Materials and Methods: Segregation analysis was performed in pedigree data from 74 families by the use of the SEGREG program of SAGE v.5.4.2. Homogeneous no transmission, homogeneous Mendelian transmission, homogeneous general transmission, semi-general transmission and heterogeneous general transmission models were tested assuming the prevalence of aggressive periodontitis as 1% and no deviations from Hardy,Weinberg equilibrium. The parameters of the model were estimated by the method of maximum likelihood, which provides the overall ln (likelihood), -2ln and the AIC (Akaike's score) for each model. The likelihood ratio test (LRT) was used to compare each model against a fully general model (p>0.05). Results: The most parsimonious mode of inheritance was the semi-general transmission model that allows the heterozygote transmission probability to vary. Conclusion: This result provides strong support for the hypothesis that genetic factors play a role in aggressive periodontitis and that a few loci, each with relatively small effects, contribute to aggressive periodontitis, with or without interaction with environmental factors. [source] The effect of low-power microwaves on the growth of bacterial populations in a plug flow reactorAICHE JOURNAL, Issue 5 2010Renzo Carta Abstract A plug flow reactor (PFR) which permits the growth of bacteria in a microwave environment is described. The apparatus is used to analyse the effect of microwave radiation at the frequency of 2.45 GHz and at 37°C on the growth rate of three bacterial species: Bacillus clausii, Pseudomonas aeruginosa, and Staphylococcus aureus. The growth constant is determined for reacting mixtures irradiated with microwaves of different powers ranging from 0 to 400 mW. Analyses show that (a) the apparatus is able to perform the experimental runs maintaining an aseptic environment; (b) under the microwave power levels examined in the present study, no effects are detected for the Bacillus clausii and Pseudomonas aeruginosa species, while for the Staphylococcus aureus species, a few small effects are found (a minimum value of the growth constant at 200 mW and an increase of the constant between 200 and 400 mW). © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] Stabilization of proteins by low molecular weight multi-ionsJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 10 2002Donald S. Maclean Abstract A method is described to identify small molecule ligands that stabilize proteins. The procedure is based on the hypothesis that molecules of various sizes containing two to four charges should occasionally bind to unpaired charged sites on the surface of proteins and by crosslinking such residues stabilize the native state of the liganded protein. A simple turbidity assay is employed that detects inhibition of protein aggregation under selected sets of conditions. Eight test proteins were screened and in all cases specific ligands were identified that inhibited protein aggregation at millimolar to micromolar concentrations. Only small effects of these stabilizers on protein biological activities were found. In some, but not all cases, circular dichroism and fluorescence studies provided direct evidence of the binding of stabilizing ligands to the proteins suggesting multiple mechanisms of stabilization. This approach should be applicable to the development of excipients for the stabilization of pharmaceutical proteins and industrial enzymes as well as serve as starting points for second-generation inhibitors of increased affinity and specificity. © 2002 Wiley-Liss Inc. and the American Pharmaceutical Association J Pharm Sci 91:2220,2229, 2002 [source] Variation in 24 hemostatic genes and associations with non-fatal myocardial infarction and ischemic strokeJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 1 2008N. L. SMITH Summary., Background:, Arterial thrombosis involves platelet aggregation and clot formation, yet little is known about the contribution of genetic variation in fibrin-based hemostatic factors to arterial clotting risk. We hypothesized that common variation in 24 coagulation,fibrinolysis genes would contribute to risk of incident myocardial infarction (MI) or ischemic stroke (IS). Methods:, We conducted a population-based, case,control study. Subjects were hypertensive adults and postmenopausal women 30,79 years of age, who sustained a first MI (n = 856) or IS (n = 368) between 1995 and 2002, and controls matched on age, hypertension status, and calendar year (n = 2689). We investigated the risk of MI and IS associated with (i) global variation within each gene as measured by common haplotypes and (ii) individual haplotypes and single nucleotide polymorphisms (SNPs). Significance was assessed using a 0.2 threshold of the false discovery rate q -value, which accounts for multiple testing. Results:, After accounting for multiple testing, global genetic variation in factor (F) VIII was associated with IS risk. Two haplotypes in FVIII and one in FXIIIa1 were significantly associated with increased IS risk (all q -values < 0.2). A plasminogen gene SNP was associated with MI risk. All are new discoveries not previously reported. Another 24 tests had P -values < 0.05 and q -values > 0.2 in MI and IS analyses, 23 of which are new and hypothesis generating. Conclusions:, Apart from the association of FVIII variation with IS, we found little evidence that common variation in the 24 candidate fibrin-based hemostasis genes strongly influences arterial thrombotic risk, but our results cannot rule out small effects. [source] Does prior psychological health influence recall of military experiences? a prospective studyJOURNAL OF TRAUMATIC STRESS, Issue 4 2008Jennifer Wilson In a prospective study, we evaluated pre- and postdeployment psychological health on recall of risk factors to assess recall bias. Measures of the General Health Questionnaire (GHQ), PTSD Checklist (PCL), and symptom clusters from the PCL were obtained from 681 UK military personnel along with information on traumatic and protective risk factors. Postdeployment psychological health was more important in explaining recall of traumatic experiences than predeployment psychological health. Predeployment intrusive cluster scores were highly associated with traumatic exposures. Postdeployment, but not predeployment GHQ showed small effects for most risk factors. With the exception of intrusive thoughts, there is insufficient evidence to suggest predeployment psychological status would be useful in correcting for recall bias in subsequent cross-sectional studies. [source] Influence of Temperature and Relative Humidity on the Friction and Wear of Unlubricated Reciprocating Sliding Steel/ Steel CouplesLUBRICATION SCIENCE, Issue 4 2004D. Klaffke Abstract Many tribosystems are subjected to different conditions with respect to temperature and humidity. Reciprocating sliding tests with steel/steel couples were performed using a laboratory test rig in air with varying relative humidity and temperature. During each test the friction force, the total linear wear, the electrical contact resistance, and the acoustic emission were recorded. Tests with self-mated couples of bearing steel (100r6) and of stainless steel (X10CrNiMoNb18-10/X5CrNi18-9) in a ball-on-disc arrangement revealed small effects of temperature and humidity on friction, but a strong effect of the water vapour content on the wear rate of the system. Attempts were made to correlate changes of wear behaviour with different wear mechanisms. [source] Internal WWAN antenna for the clamshell mobile phone with various chassis shapesMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 9 2010Kin-Lu Wong Abstract Stable performances of an internal WWAN antenna applied in the clamshell mobile phone with various chassis shapes are obtained. Six different states including five possible operating states and one closed state (idle condition) of the clamshell mobile phone, wherein the chassis shapes (main ground and upper ground) vary greatly, are studied. The WWAN antenna is mounted at the bottom of the main ground, and there are three connecting positions between the main ground and the upper ground. For each operating states, the upper ground is connected to the main ground at one of the three connecting positions. At each position, a band-stop circuit formed by two parallel LC chip elements is embedded, which is designed to excite a parallel resonance at around 900 MHz and hence leads to very high impedance seen into the upper ground in the 900 MHz band. This greatly decreases the excited surface currents on the upper ground, making the presence of the upper ground to have very small effects on the performances of the WWAN antenna mounted at the bottom of the main ground. At around 1900 MHz, owing to its shorter wavelength, the surface currents on the upper ground excited by the WWAN antenna on the main ground are small. Thus, over both the 900- and 1900-MHz bands, the various orientations of the upper ground to the main ground cause small effects on the WWAN antenna embedded therein. Details of the obtained results are presented. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 2148,2154, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25413 [source] Can Changes in Differential Dropout Rates Reduce Adverse Impact?PERSONNEL PSYCHOLOGY, Issue 4 2004A Computer Simulation Study of a Multi-wave Selection System A simulation was used to explore the effects of variations in the rate at which applicants drop out of selection processes on racial differences in selection outcomes. Archival data was used to simulate a realistic range of selection scenarios in which test score differences between groups and selection ratios varied. The basis for dropping out was manipulated in two separate studies. Study 1 simulated dropout decisions that occurred at random within racial subgroups; in this study, dropout rates of minority versus White candidates were varied. Study 2 examined dropout decisions that occurred as a function of test scores. Results from both studies showed that mean test score differences between White and minority applicants have the largest influence on adverse impact. Interventions designed to reduce the tendency of minority applicants to withdraw from selection are likely to have, at best, small effects on the adverse impact of selection tests. [source] Estimates of Pregnancies Averted Through California's Family Planning Waiver Program in 2002PERSPECTIVES ON SEXUAL AND REPRODUCTIVE HEALTH, Issue 3 2006Diana Greene Foster CONTEXT: During its first year of operation (1997-1998), California's family planning program, Family PACT, helped more than 750,000 clients to avert an estimated 108,000 pregnancies. Given subsequent increases in the numbers of clients served and contraceptive methods offered by the program, updated estimates of its impact on fertility are needed. METHODS: Claims data on contraceptives dispensed were used to estimate the number of pregnancies experienced by women in the program in 2002. Medical record data on methods used prior to enrollment were used to predict client fertility in the absence of the program. Further analyses examined the sensitivity of these estimates to alternative assumptions about contraceptive failure rates, contraceptive continuation and contraceptive use in the absence of program services. RESULTS: Almost 6.4 million woman-months of contraception, provided primarily by oral contraceptives (57%), barrier methods (19%) and the injectable (18%), were dispensed through Family PACT during 2002. As a result, an estimated 205,000 pregnancies,which would have resulted in 79,000 abortions and 94,000 births, including 21,400 births to adolescents,were averted. Changing the base assumptions regarding contraceptive failure rates or method use had relatively small effects on the estimates, whereas assuming that clients would use no contraceptives in the absence of Family PACT nearly tripled the estimate of pregnancies averted. CONCLUSIONS: Because all contraceptive methods substantially reduce the risk of pregnancy, Family PACT'S impact on preventing pregnancy lies primarily in providing contraceptives to women who would otherwise not use any method. [source] Isovitexin-2,- O -,-[6- O -E- p -coumaroylglucopyranoside] from UV-B irradiated Leaves of Rice, Oryza sativa L. Inhibits Fertility of Helicoverpa armigeraPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 5 2007Merdelyn T. Caasi-Lit UV-B irradiated rice leaves (Oryza sativa L.) contained four closely related flavonoids, with either an isoorientin or isovitexin aglycone. These flavonoids have previously been purified and characterized, and were added to artificial diets of the African bollworm (Helicoverpa armigera Hübner) at 0.1× concentration found in irradiated rice leaves. Consumption of different diets had relatively small effects on laval, pupal and adult duration, weight and survival, indicating the insects lived near normal life cycles on all diets. However, one of the compounds, flavonoid IIa, isovitexin-2,- O -,-[6- O -E- p -coumaroylglucopyranoside], dramatically reduced the number of fertile eggs laid to 7% of control insects (P < 0.001) when added to insect diets at 18 nmol gFW,1 (14 ppm). A similar antifertility effect was observed when only the male partner consumed diet containing flavonoid IIa, indicating that the reduced fertility may be male specific. In contrast, the fecundity and fertility of insects eating diets containing the closely related flavonoids, isoorientin-2,- O -,-[6- O -E- p -coumaroylglucopyranoside] or isoorientin-2,- O -,-[6- O -E- p -feruloylglucopyranoside], were not significantly different to control diets. [source] THE IMPACT OF PUBLIC MANAGEMENT REFORMS ON STUDENT PERFORMANCE IN DANISH SCHOOLSPUBLIC ADMINISTRATION, Issue 2 2008SIMON CALMAR ANDERSEN Many resources have been invested in reforming the public sectors of most countries in the world during the last 20 years. Greater focus on evaluation and performance is one of the most central aspects of these reforms, but despite much academic research virtually no systematic evaluations of the outcome of the reforms themselves are found. This paper presents a study of the effect of performance management reforms of Danish public schools on the achievements of more than 80,000 lower secondary students. The study finds no or very small effects on performance measured as average exam scores, but highly significant effects on inequity in the sense that students with low socioeconomic status perform worse at reforming schools than at similar non-reforming schools. These results, as well as the methodological challenges involved in estimating reform impact, emphasize the need for more empirical scrutiny of what effects the reforms have. [source] Effects of Restoration on Plant Species Richness and Composition in Scandinavian Semi-Natural GrasslandsRESTORATION ECOLOGY, Issue 3 2004Regina Lindborg Abstract Plant species richness in rural landscapes of northern Europe has been positively influenced by traditional management for millennia. Owing to abandonment of these practices, the number of species-rich semi-natural grasslands has decreased, and remaining habitats suffer from deterioration, fragmentation, and plant species decline. To prevent further extinctions, restoration efforts have increased during the last decades, by reintroducing grazing in former semi-natural grasslands. To assess the ecological factors that might influence the outcome of such restorations, we made a survey of semi-natural grasslands in Sweden that have been restored during the last decade. We investigated how plant species richness, species density, species composition, and abundance of 10 species that are indicators of grazing are affected by (1) the size of the restored site, (2) the time between abandonment of grazing and restoration, (3) the time elapsed since restoration, and (4) the abundance of trees and shrubs at the restored site. Only two factors, abundance of trees and shrubs and time since restoration, were positively associated with total species richness and species density per meter square at restored sites. Variation in species composition among restored sites was not related to any of the investigated factors. Species composition was relatively similar among sites, except in mesic/wet grasslands. The investigated factors had small effects on the abundance of the grazing-indicator species. Only Campanula rotundifolia responded to restoration with increasing abundance and may thus be a suitable indicator of improved habitat quality. In conclusion, positive effects on species richness may appear relatively soon after restoration, but rare, short-lived species are still absent. Therefore, remnant populations in surrounding areas may be important in fully recreating former species richness and composition. [source] Heritabilities and quantitative trait loci for blood gases and blood pH in swineANIMAL GENETICS, Issue 2 2009G. Reiner Summary Maintaining pH and blood gases in a narrow range is essential to sustain normal biochemical reactions. Decreased oxygenation, poor tissue perfusion, disturbance to CO2 expiration, and shortage of HCO3, can lead to metabolic acidosis. This is a common situation in swine, and originates from a broad range of medical conditions. pH and blood gases appear to be under genetic control, and populations with physiological traits closer to the pathological thresholds may be more susceptible to developing pathological conditions. However, little is known about the genetic basis of such traits. We have therefore estimated phenotypic and genetic variability and identified quantitative trait loci (QTL) for pH and blood gases in blood samples from 139 F2 pigs from the Meishan/Pietrain family. Samples were taken before and after challenge with Sarcocystis miescheriana, a protozoan parasite of muscle. Twenty-seven QTL influencing pH and blood gases were identified on nine chromosomes. Five of the QTL were significant on a genome-wide level; 22 QTL were significant on a chromosome-wide level. QTL for pH-associated traits have been mapped to SSC3, 18 and X. QTL associated with CO2 have been detected on SSC6, 7, 8 and 9, and QTL associated with O2 on SSC2 and SSC8. QTL showed specific health/disease patterns that were related to the physiological state of the pigs from day 0, to acute disease (day 14), convalescence (day 28) and chronic disease (day 42). The results demonstrate that pH and blood gases are influenced by multiple chromosomal areas, each with relatively small effects. [source] In vitro micro-tuber initiation and dormancy in yamANNALS OF APPLIED BIOLOGY, Issue 2 2010E.I. Hamadina Dormancy is a mechanism that regulates the timing of sprouting (germination) of affected plant parts as well as ensures that the food quality of edible parts is maintained in storage until the following growing season. In yam, however, little is known about the control of tuber initiation or tuber dormancy. The objective of this study was to determine the effects of selected plant growth regulators (PGRs) on tuber initiation and dormancy, using an in vitro system. In two replicated experiments, 2-chloroethylphosphonic acid (ethephon, an ethylene source), abscisic acid (ABA) and gibberellin (GA3) , and their inhibitors silver nitrate, fluridone and 2-chloroethyl-trimethylammonium chloride, respectively , were added at two concentrations to the culture medium prior to explant culture. Dates of micro-tuber initiation and sprouting (end of dormancy) and tuber number were recorded. In the control (no PGR) in Experiment 1, micro-tubers were initiated at the base of the stem after 176 days and sprouted 235 days later, that is 411 days after culturing. Most PGR treatments had only small effects (±30 days) on the duration of dormancy and the time of micro-tuber initiation. However, in GA3 micro-tuber initiation occurred after 76 days, about 100 days earlier than in the control, whereas fluridone affected the position of micro-tubers and duration of dormancy. With fluridone treatments, tubers were found at the base of the stem (normal position) and on lower and upper nodes. Lower node tubers sprouted within 225 days of culturing compared with about 420 days after culturing at other nodal positions and in other PGR treatments. These data suggest an important role for ABA and gibberellic acid in yam micro-tuber initiation and the induction of dormancy. [source] Spatially explicit trophic modelling of a harvested benthic ecosystem in Tongoy Bay (central northern Chile)AQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 6 2002Marco Ortiz Abstract 1.A dynamical and spatial simulation model of a harvested benthic ecosystem of central northern Chile (Tongoy Bay) was constructed using the ECOSPACE software package. 2.In this system the red alga (Chondrocanthus chamissoi), the scallop (Argopecten pupuratus), the gastropod (Xanthochorus cassidiformis) and the crab (Cancer polyodon) are harvested intensively. The impacts of harvesting these resources exclusively in the seagrass, sand-gravel, and in the sand habitats, as well as, in the seagrass and sand-gravel and in all habitats were assessed. The goal was to explore policies of sustainable exploitation of the benthic systems. 3.The most important findings were: (a) Fishing exclusively in either the seagrass or sand habitats produces a population increase in the sea star Luidia magallanica, in the seagrass Heterozostera tasmanica, and in the crab Paraxanthus barbiger. (b) Exclusive fishing in the sand-gravel habitat causes only small effects on the species and groups, which suggests that this habitat is the most resistant to harvest. (c) The simultaneous fishing on two or three habitats would produce the largest negative effect on the entire system. Therefore, a habitat rotation fishery is recommended. 4.Our study suggests that trophic-spatially explicit models offer great possibilities for the screening and planning of effective interventions or manipulations of natural systems. Copyright © 2002 John Wiley & Sons, Ltd. [source] A randomized crossover trial of a wedged insole for treatment of knee osteoarthritis,ARTHRITIS & RHEUMATISM, Issue 4 2007Kristin Baker Objective In uncontrolled studies, a lateral-wedge insole has reduced knee pain in patients with medial knee osteoarthritis (OA). The aim of this study was to test the efficacy of this simple, low-cost intervention for pain in patients with medial knee OA. Methods We conducted a double-blind, randomized, crossover trial designed to detect a small effect of treatment. Participants were at least 50 years of age and had medial joint space narrowing on posteroanterior semiflexed radiographs and scores indicating moderate pain for 2 of the 5 items on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain scale. Participants were randomized to receive a 5° lateral-wedge insole or a neutral insole for 6 weeks. Following a 4-week washout period, participants crossed over to the other treatment for 6 weeks. Knee pain, the primary outcome, was assessed by the WOMAC pain scale (visual analog scale version). Secondary outcomes included the WOMAC disability subscale, overall knee pain, 50-feet walk time, chair-stand time, and use of medications for knee pain. Results Ninety patients were randomized. The mean difference in pain between the 2 treatments was 13.8 points on the WOMAC pain scale (95% confidence interval ,3.9, 31.4 [P = 0.13]). We observed similar small effects for the secondary outcomes. Conclusion The effect of treatment with a lateral-wedge insole for knee OA was neither statistically significant nor clinically important. [source] Effects of nominally selective inhibitors of the kinases PI3K, SGK1 and PKB on the insulin-dependent control of epithelial Na+ absorptionBRITISH JOURNAL OF PHARMACOLOGY, Issue 3 2010Morag K Mansley BACKGROUND AND PURPOSE Insulin-induced Na+ retention in the distal nephron may contribute to the development of oedema/hypertension in patients with type 2 diabetes. This response to insulin is usually attributed to phosphatidylinositol-3-kinase (PI3K)/serum and glucocorticoid-inducible kinase 1 (SGK1) but a role for protein kinase B (PKB) has been proposed. The present study therefore aimed to clarify the way in which insulin can evoke Na+ retention. EXPERIMENTAL APPROACH We examined the effects of nominally selective inhibitors of PI3K (wortmannin, PI103, GDC-0941), SGK1 (GSK650394A) and PKB (Akti-1/2) on Na+ transport in hormone-deprived and insulin-stimulated cortical collecting duct (mpkCCD) cells, while PI3K, SGK1 and PKB activities were assayed by monitoring the phosphorylation of endogenous proteins. KEY RESULTS Wortmannin substantially inhibited basal Na+ transport whereas PI103 and GDC-0941 had only very small effects. However, these PI3K inhibitors all abolished insulin-induced Na+ absorption and inactivated PI3K, SGK1 and PKB fully. GSK650394A and Akti-1/2 also inhibited insulin-evoked Na+ absorption and while GSK650394A inhibited SGK1 without affecting PKB, Akti-1/2 inactivated both kinases. CONCLUSION AND IMPLICATIONS While studies undertaken using PI103 and GDC-0941 show that hormone-deprived cells can absorb Na+ independently of PI3K, PI3K seems to be essential for insulin induced Na+ transport. Akti-1/2 does not act as a selective inhibitor of PKB and data obtained using this compound must therefore be treated with caution. GSK650394A, on the other hand, selectively inhibits SGK1 and the finding that GSK650394A suppressed insulin-induced Na+ absorption suggests that this response is dependent upon signalling via PI3K/SGK1. [source] | |||||||||||||||||||||||||