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Substantial Effects (substantial + effects)
Selected AbstractsEffect of Interictal Spikes on Single-Cell Firing Patterns in the HippocampusEPILEPSIA, Issue 4 2007Jun-Li Zhou Summary:,Purpose: The interictal EEG spike(s) is the hallmark of the epileptic EEG. While focal interictal spike (IS) have been associated with transitory cognitive impairment, with the type of deficit dependent on where in the cortex the IS arises, the mechanism by which IS result in transitory dysfunction is not known. The purpose of this study was to determine the effect of IS on single-cell firing patterns in freely moving rats with a prior history of seizures. Methods: We studied IS in two seizure models; pilocarpine-induced status epilepticus and recurrent flurothyl models. The effect of spontaneous hippocampal spikes on action potentials (APs) of CA1 cells in rats walking in a familiar environment was investigated using 32 extracellular electrodes. We also compared the effect of spikes on two types of hippcampal cells; place cells that discharge rapidly only when the rat's head is in a specific part of the environment, the so-called firing field, and interneurons, which are a main source of inhibition in the hippocampus. Results: IS were associated with a decreased likelihood of AP compared with IS-free portions of the record. Compared to pre-IS baseline, IS were followed by significant decreases in CA1 APs for periods up to 2 s following the IS in both models. When occurring in flurries, IS were associated with a pronounced decrease in APs. The response to IS was cell-dependent; IS resulted in decreases in AP firing after the IS in interneurons but not place cells. Conclusions: This study demonstrates that IS have substantial effects on cellular firing in the hippocampus and that these effects last far longer than the spike and slow wave. Furthermore, the effect of IS on cellular firing was cell specific, affecting interneurons more than place cells. These findings suggest that IS may contribute to seizure-induced cognitive impairment by altering AP firing in a cell-specific manner. [source] Policy decisiveness and responses to speculative attacks in developed countriesEUROPEAN JOURNAL OF POLITICAL RESEARCH, Issue 6 2009KYUNG JOON HAN Why are some countries able to defend their currencies when there are speculative attacks, while others fail to do so and devalue their currencies? This article suggests that intragovernment factors as well as government-legislature relations should be considered because many of the policy responses to speculative attacks do not require legislative acquiescence, so that intragovernment attributes will have more substantial effects on the policy responses than those of government-legislature relations. This article suggests that cleavages within government and its instability have a negative effect on decisiveness. Data regarding speculative attacks in developed countries from the 1970s to the 1990s and the Heckman selection model show that governments with many veto players and with less durability have had difficulty in defending their currencies in the face of speculative attacks. The article also finds that governmental institutional effects can be constrained by central bank independence. The effects become substantially smaller and statistically insignificant when central banks are very independent. The overall results imply that policy indecisiveness induced by some political factors makes governments less able to adopt a new policy equilibrium that is necessary to respond to an exogenous shock such as speculative attack. [source] Parental Deployment and Youth in Military Families: Exploring Uncertainty and Ambiguous Loss,FAMILY RELATIONS, Issue 2 2007Angela J. Huebner Abstract: Parental deployment has substantial effects on the family system, among them ambiguity and uncertainty. Youth in military families are especially affected by parental deployment because their coping repertoire is only just developing; the requirements of deployment become additive to normal adolescent developmental demands. Focus groups were used to inquire about uncertainty, loss, resilience, and adjustment among youth aged 12,18 that had a parent deployed, most often to a war zone. The nature of uncertainty and ambiguous loss was explored. Response themes included overall perceptions of uncertainty and loss, boundary ambiguity, changes in mental health, and relationship conflict. These accounts suggest that ambiguous loss is a useful concept for understanding the experiences of these youth and for structuring prevention and intervention efforts. [source] IN BETWEEN CURING AND COUNTING: PERFORMATIVE EFFECTS OF EXPERIMENTS WITH HEALTHCARE INFORMATION INFRASTRUCTUREFINANCIAL ACCOUNTABILITY & MANAGEMENT, Issue 3 2007Signe Vikkelsø Performance standards and accountability pervade modern healthcare. According to Michael Power, this may signify a new rationality of governance characterized by control of controls, which affects practices not by direct intervention, but through the processes by which practices are made auditable. The paper addresses this thesis by exploring the construction of a Danish standard for electronic patient records. It is shown that making healthcare auditable activates deep tensions between programs of clinical practice, quality control, evidence based medicine, and casemix funding, resulting in an ambiguous and unstable standard. During this process, however, particular notions of patients, diseases, and diagnoses emerge as undisputed innovations, which may come to survive the subsequent career of the standard. The paper discusses the performative effects of these innovations and argues that information infrastructure has become an analytically important site for exploring the substantial effects of new rationalities of governance in healthcare. [source] Predicting population consequences of ocean climate change for an ecosystem sentinel, the seabird Cassin's aukletGLOBAL CHANGE BIOLOGY, Issue 7 2010SHAYE G. WOLF Abstract Forecasting the ecological effects of climate change on marine species is critical for informing greenhouse gas mitigation targets and developing marine conservation strategies that remain effective and increase species' resilience under changing climate conditions. Highly productive coastal upwelling systems are predicted to experience substantial effects from climate change, making them priorities for ecological forecasting. We used a population modeling approach to examine the consequences of ocean climate change in the California Current upwelling ecosystem on the population growth rate of the planktivorous seabird Cassin's auklet (Ptychoramphus aleuticus), a demographically sensitive indicator of marine climate change. We use future climate projections for sea surface temperature and upwelling intensity from a regional climate model to forecast changes in the population growth rate of the auklet population at the important Farallon Island colony in central California. Our study projected that the auklet population growth rate will experience an absolute decline of 11,45% by the end of the century, placing this population on a trajectory toward extinction. In addition, future changes in upwelling intensity and timing of peak upwelling are likely to vary across auklet foraging regions in the California Current Ecosystem (CCE), producing a mosaic of climate conditions and ecological impacts across the auklet range. Overall, the Farallon Island Cassin's auklet population has been declining during recent decades, and ocean climate change in this century under a mid-level emissions scenario is projected to accelerate this decline, leading toward population extinction. Because our study species has proven to be a sensitive indicator of oceanographic conditions in the CCE and a powerful predictor of the abundance of other important predators (i.e. salmon), the significant impacts we predicted for the Cassin's auklet provide insights into the consequences that ocean climate change may have for other plankton predators in this system. [source] The Diffusion of Calculative and Collaborative HRM Practices in European FirmsINDUSTRIAL RELATIONS, Issue 4 2006ERIK POUTSMA The aim of this paper is to trace and explain variations in calculative and collaborative human resource management (HRM) practices between companies and across national borders. Variations and similarities are explained in terms of the convergence and divergence of HRM practices determined by national institutions, and the increasing influence of multinational companies (MNCs). We explore the diffusion of HRM practices in Europe over time, using data sets from two surveys conducted in several European countries in 1995 and 2000. We use institutional explanations for the development of three selected bundles of HRM practices: individual, calculative performance-oriented practices; collective incentive schemes for the alignment of interests; and collaborative practices that seek to enhance the commitment of employees. We found substantial effects of country-specific institutions and of the country of origin of MNCs, which clearly support the institutional duality thesis. Foreign-owned MNCs, especially those that are US-based, appear to moderate country-specific institutional effects on the diffusion of the three HRM bundles. [source] Solar correlates of Southern Hemisphere mid-latitude climate variabilityINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 8 2002Ronald E. Thresher Abstract Atmospheric circulation in the southern mid-latitudes is dominated by strong circum-Antarctic zonal west winds (ZWW) over the latitude range of 35 to 60°S. These winds exhibit coherent seasonal and interannual variability, which has been related both to Antarctic (e.g. polar ice) and low-latitude climate (e.g. El Niño,southern oscillation) parameters. Historical and recent studies suggest that, at its northern margins, variability in the ZWW also has a marked quasi-decadal component. Analysis of sea-level pressure and rainfall data for the Australian region, South Africa and South America confirms frequent indications of quasi-decadal variability in parameters associated with the ZWW, which appears to be in phase around the hemisphere. This variation broadly correlates with the sunspot cycle, and specifically appears to reflect sunspot-correlated, seasonally modulated shifts in the latitude range each year of the sub-tropical ridge over eastern Australia. Sunspot-correlated variability in the southern mid-latitudes is likely to have substantial effects on temperate climate and ecology and is consistent with recent models of solar effects on upper atmospheric climate, though the mechanisms that link these to winds and rainfall at sea level remain obscure. Copyright © 2002 Royal Meteorological Society [source] Do Noneconomic Damages Caps and Attorney Fee Limits Reduce Access to Justice for Victims of Medical Negligence?JOURNAL OF EMPIRICAL LEGAL STUDIES, Issue 4 2009Steven Garber We analyze effects of noneconomic damages caps and attorney fee limits (AFLs) on the ability of people injured by negligent physicians to retain qualified lawyers to represent them. We employ survey data from 965 plaintiffs' attorneys who reported likelihoods of accepting hypothetical meritorious cases described by scenarios. We estimate how willingness to accept such cases increases with the expected hourly fees associated with them, and the estimates suggest substantial effects and plausible tradeoffs. We conclude that caps and AFLs make it harder to retain counsel in various circumstances, and we present policy simulations elucidating how several factors combine to determine these effects. [source] Effects of vibration treatment on tibial bone of ovariectomized rats analyzed by in vivo micro-CTJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 1 2010Julienne E.M. Brouwers Abstract Daily low-amplitude, high-frequency whole-body vibration (WBV) treatment can increase bone formation rates and bone volume in rodents. Its effects vary, however, with vibration characteristics and study design, and effects on 3D bone microstructure of ovariectomized animals over time have not been documented. Our goal was to determine the effects of WBV on tibial bone of ovariectomized, mature rats over time using an in vivo micro-CT scanner. Adult rats were divided into: ovariectomy (OVX) (n,=,8), SHAM-OVX (n,=,8), OVX and WBV treatment (n,=,7). Eight weeks after OVX, rats in the vibration group were placed on a vibrating platform for 20,min at 0.3,g and 90 Hertz. This was done 5 days a week for six weeks, twice a day. Zero, 8, 10, 12 and 14 weeks after OVX, in vivo micro-CT scans were made (vivaCT 40, Scanco Medical AG) of the proximal and diaphyseal tibia. After sacrifice, all tibiae were dissected and tested in three-point bending. In the metaphysis between 8 to 12 weeks after OVX, WBV treatment did not alter structural parameters compared to the OVX group and both groups continued to show deterioration of bone structure. In the epiphysis, structural parameters were not altered. WBV also did not affect cortical bone and its bending properties. To summarize, no substantial effects of 6 weeks of low-magnitude, high-frequency vibration treatment on tibial bone microstructure and strength in ovariectomized rats were found. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:62,69, 2010 [source] Can We Identify Genes For Alcohol Consumption In Samples Ascertained For Heterogeneous Purposes?ALCOHOLISM, Issue 4 2009Narelle K. Hansell Background:, Previous studies have identified evidence of genetic influence on alcohol use in samples selected to be informative for alcoholism research. However, there are a growing number of genome-wide association studies (GWAS) using samples unselected for alcohol consumption (i.e., selected on other traits and forms of psychopathology), which nevertheless assess consumption as a risk factor. Is it reasonable to expect that genes contributing to variation in alcohol consumption can be identified in such samples? Methods:, An exploratory approach was taken to determine whether linkage analyses for heaviness of alcohol consumption, using a sample collected for heterogeneous purposes, could replicate previous findings. Quantity and frequency measures of consumption were collected in telephone interviews from community samples. These measures, and genotyping, were available for 5,441 individuals (5,067 quasi-independent sibling pairs). For 1,533 of these individuals, data were collected on 2 occasions, about 8.2 years apart, providing 2 datasets that maximize data collected at either a younger or an older age. Analyses were conducted to address the question of whether age and heavier levels of alcohol consumption effects outcome. Linkage results were compared in the younger and older full samples, and with samples in which approximately 10, 20, and 40 of drinkers from the lower end of the distribution of alcohol consumption were dropped. Results:, Linkage peaks varied for the age differentiated samples and for percentage of light drinkers retained. Larger peaks (LOD scores >2.0) were typically found in regions previously identified in linkage studies and/or containing proposed candidate genes for alcoholism including AGT, CARTPT, OPRD1, PIK3R1, and PDYN. Conclusions:, The results suggest that GWAS assessing alcohol consumption as a covariate for other conditions will have some success in identifying genes contributing to consumption-related variation. However, sample characteristics, such as participant age, and trait distribution, may have substantial effects on the strength of the genetic signal. These results can inform forthcoming GWAS where the same restrictions apply. [source] RATES, RIGHTS, AND REGIONAL PLANNING IN THE METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 5 2002Richard Atwater ABSTRACT: The Metropolitan Water District of Southern California has for more than 70 years shaped the development of an immense urban region. The district's current strategic planning process therefore could have substantial effects on regional water planning and management. The rate restructuring phase of the planning process has produced a multiple component, cost of service based framework. This paper describes that framework as well as some criticisms that have been directed toward it. The rate restructuring was shaped, and for a while stalled, by old disputes among member agencies over rights to water supplied by Metropolitan. That controversy has diverted attention from the resource management implications of the rate structure. This paper presents an alternative future focused approach to regional integrated water resource planning for Southern California based on projections of current trends and anticipation of future events. This discussion raises the question of how regional integrated water resources planning of this sort may proceed, and what role Metropolitan will play in that process. [source] Meta-analysis of transmitter effects on avian behaviour and ecologyMETHODS IN ECOLOGY AND EVOLUTION, Issue 2 2010Douglas G. Barron Summary 1. Researchers often attach transmitters and other devices to free-living birds without a clear understanding of potential deleterious consequences to their study organisms, and thus to their data. Studies investigating this topic have generally been limited to a single species or type of device. 2. To achieve a broader understanding we used a meta-analysis of 84 studies to ask: (1) Do devices have an overall effect on birds? (2) Which aspects of avian behaviour and ecology are affected? (3) What attributes of birds influence transmitter effects? (4) What attributes of devices influence their effects? (5) Are effects partially a consequence of capture and restraint? 3. We found a significant negative effect of devices on birds, both overall and for 8 of the 12 specific aspects analysed. The most substantial effects were that birds with devices had markedly increased energy expenditure and were much less likely to nest. 4. Effects were independent of attributes of the birds (sex, age, primary method of locomotion and body mass). We also found no evidence that proportionally heavier devices had greater effects, although researchers generally avoided using heavy devices. Breast-mounted and harness attachments increased device-induced behaviours such as preening, however, and the risk of device-induced mortality differed between attachment methods. 5. Other than foraging behaviours, no effects were a consequence of capture or restraint. 6.Synthesis and applications. We provide the first comprehensive evidence that transmitters and other devices negatively affect birds and may bias resulting data. Researchers should balance the benefits of using these techniques against potential costs to the birds and reliability of the data obtained. [source] Distance dependence and salt sensitivity of pairwise, coulombic interactions in a proteinPROTEIN SCIENCE, Issue 5 2002Kelly K. Lee Abstract Histidine pKa values were measured in charge-reversal (K78E, K97E, K127E, and K97E/K127E) and charge-neutralization (E10A, E101A, and R35A) mutants of staphylococcal nuclease (SNase) by 1H-NMR spectroscopy. Energies of interaction between pairs of charges (,Gij) were obtained from the shifts in pKa values relative to wild-type values. The data describe the distance dependence and salt sensitivity of pairwise coulombic interactions. Calculations with a continuum electrostatics method captured the experimental ,Gij when static structures were used and when the protein interior was treated empirically with a dielectric constant of 20. The ,Gij when rij , 10 Å were exaggerated slightly in the calculations. Coulomb's law with a dielectric constant near 80 and a Debye-Hückel term to account for screening by the ionic strength reproduced the salt sensitivity and distance dependence of ,Gij as well as the structure-based method. In their interactions with each other, surface charges behave as if immersed in water; the Debye length describes realistically the distance where interactions become negligible at a given ionic strength. On average, charges separated by distances (rij) ,5 Å interacted with ,Gij , 0.6 kcal/mole in 0.01 M KCl, but ,Gij decayed to ,0.10 kcal/mole when rij = 20 Å. In 0.10 M KCl, ,Gij , 0.10 kcal/mole when rij = 10 Å. In 1.5 M KCl, only short-range interactions with rij , 5 Å persisted. Although at physiological ionic strengths the interactions between charges separated by more than 10 Å are extremely weak, in situations where charge imbalance exists many weak interactions can cumulatively produce substantial effects. [source] Introduced birds in urban remnant vegetation: Does remnant size really matter?AUSTRAL ECOLOGY, Issue 2 2006MARK J. ANTOS Abstract Introduced birds are a pervasive and dominant element of urban ecosystems. We examined the richness and relative abundance of introduced bird species in small (1,5 ha) medium (6,15 ha) and large (>15 ha) remnants of native vegetation within an urban matrix. Transects were surveyed during breeding and non-breeding seasons. There was a significant relationship between introduced species richness and remnant size with larger remnants supporting more introduced species. There was no significant difference in relative abundance of introduced species in remnants of different sizes. Introduced species, as a proportion of the relative abundance of the total avifauna (native and introduced species), did not vary significantly between remnants of differing sizes. There were significant differences in the composition of introduced bird species between the different remnant sizes, with large remnants supporting significantly different assemblages than medium and small remnants. Other variables also have substantial effects on the abundance of introduced bird species. The lack of significant differences in abundance between remnant sizes suggests they were all equally susceptible to invasion. No patches in the urban matrix are likely to be unaffected by introduced species. The effective long-term control of introduced bird species is difficult and resources may be better spent managing habitat in a way which renders it less suitable for introduced species (e.g. reducing areas of disturbed ground and weed dominated areas). [source] Labour Market Policies and Long-term Unemployment in a Flow Model of the Australian Labour MarketAUSTRALIAN ECONOMIC PAPERS, Issue 2 2003Ric D. Herbert This paper develops a general equilibrium job matching model, which is used to assess the impact of active labour market policies, reductions in unemployment benefits and reductions in worker bargaining power on long-term unemployment and other key macro variables. The model is calibrated using Australian data. Simulation experiments are conducted through impulse response analysis. The simulations suggest that active labour market programs (ALMPs) targeted at the long-term unemployed have a small net impact and produce adverse spillover effects on short-term unemployment. Reducing the level of unemployment benefits relative to wages and worker bargaining power have more substantial effects on total and long-term unemployment and none of the spillover effects of ALMPs. [source] Degradation of Chlorocarbons Driven by Hydrodynamic CavitationCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 5 2007Z.-L. Wu Abstract To provide an efficient lab-scale device for the investigation of the degradation of organic pollutants driven by hydrodynamic cavitation, the degradation kinetics of chloroform and carbon tetrachloride and the increase of conductivity in aqueous solutions were measured. These are values which were not previously available. Under hydrodynamic cavitation conditions, the degradation kinetics for chlorocarbons was found to be pseudo first-order. Meanwhile, C-H and C-Cl bonds are broken, and Cl2, Cl., Cl, and other ions released can increase the conductivity and enhance the oxidation of KI in aqueous solutions. The upstream pressures of the orifice plate, the cavitation number, and the solution temperature have substantial effects on the degradation kinetics. A decreased cavitation number can result in more cavitation events and enhances the degradation of chlorocarbons and/or the oxidation of KI. A decrease in temperature is generally favorable to the cavitation chemistry. Organic products from the degradation of carbon tetrachloride and chloroform have demonstrated the formation and recombination of free radicals, e.g., CCl4, C2Cl4, and C2Cl6 are produced from the degradation of CHCl3. CHCl3 and C2Cl6 are produced from the degradation of CCl4. Both the chemical mechanism and the reaction kinetics of the degradation of chlorocarbons induced by hydrodynamic cavitation are consistent with those obtained from the acoustic cavitation. Therefore, the technology of hydrodynamic cavitation should be a good candidate for the removal of organic pollutants from water. [source] | ||||||||||||||||||||||