Plausible Changes Research Articles

AGE AND DISTANCE FOR THE OLD OPEN CLUSTER NGC 188 FROM THE ECLIPSING BINARY MEMBER V 12

We present time-series radial-velocity and photometric observations of a solar-type double-lined eclipsing binary star (V12) near the turnoff in the old open cluster NGC188. We use these data to determine the spectroscopic orbit and the photometric elements for V12. From our analysis we determine accurate masses (Mp=1.103+-0.007Msun, Ms=1.081+-0.007Msun) and radii (R =1.424+-0.019Rsun, Rs=1.373+-0.019Rsun) for the primary (p) and secondary (s) binary components. We adopt a reddening of E_(B-V)=0.087 for NGC188, and derive component effective temperatures of 5900+-100K and 5875+-100K, respectively, for the primary and secondary stars. From their absolute dimensions, the two components of V12 yield identical distance moduli of Vo-MV=11.24+-0.09, corresponding to 1770+-75pc. We determine an age of 6.2+-0.2Gyr for V12 and NGC188, from a comparison with theoretical isochrones in the mass-radius diagram. This age is independent of distance, reddening, and color-temperature transformations. We use isochrones from Victoria-Regina (VRSS) and Yonsei-Yale (Y2) with [Fe/H]=-0.1 and [Fe/H]=0.0. From the solar metallicity isochrones, an age of 6.4Gyr provides the best fit to the binary components for both sets of models. For the isochrones with [Fe/H]=-0.1, ages of 6.0Gyr and 5.9Gyr provide the best fits for the VRSS and Y2 models, respectively. We use the distance and age estimates for V12, together with best estimates for the metallicity and reddening of NGC188, to investigate the locations of the corresponding VRSS and Y2 isochrones relative to cluster members in the color-magnitude diagram. Plausible changes in model metallicity and distance to better match the isochrones to the cluster sequences, result in a range of ages for NGC188 that is more than 3 times that resulting from our analysis of V12.

Robust mechanisms of ventral furrow invagination require the combination of cellular shape changes

Ventral furrow formation in Drosophila is the first large-scale morphogenetic movement during the life of the embryo, and is driven by co-ordinated changes in the shape of individual epithelial cells within the cellular blastoderm. Although many of the genes involved have been identified, the details of the mechanical processes that convert local changes in gene expression into whole-scale changes in embryonic form remain to be fully understood. Biologists have identified two main cell deformation modes responsible for ventral furrow invagination: constriction of the apical ends of the cells (apical wedging) and deformation along their apical–basal axes (radial lengthening/shortening). In this work, we used a computer 2D finite element model of ventral furrow formation to investigate the ability of different combinations of three plausible elementary active cell shape changes to bring about epithelial invagination: ectodermal apical–basal shortening, mesodermal apical–basal lengthening/shortening and mesodermal apical constriction. We undertook a systems analysis of the biomechanical system, which revealed many different combinations of active forces (invagination mechanisms) were able to generate a ventral furrow. Two important general features were revealed. First that combinations of shape changes are the most robust to environmental and mutational perturbation, in particular those combining ectodermal pushing and mesodermal wedging. Second, that ectodermal pushing plays a big part in all of the robust mechanisms (mesodermal forces alone do not close the furrow), and this provides evidence that it may be an important element in the mechanics of invagination in Drosophila.

Short Article: Recognition accuracy for original and altered verbal memory reports in older adults

The current study examined four factors that were expected to influence recognition accuracy of previously retrieved events: remoteness of the event, rated emotionality of the event, the type of changes that were made to the original memory report, and the plausibility of these changes. This was done in a study with 33 participants who were tested for recognition accuracy of original and altered reports a year after they had initially reported these autobiographical memories. Participants evaluated original and altered reports as being authentic or not. High recognition accuracy occurred for report evaluations of events that were recent, that contained central changes, and that had higher emotional intensity ratings. Recognition errors were more likely to occur when the original events were remote and when altered reports contained peripheral and plausible changes. These findings demonstrate the vulnerability of recognition accuracy in older adults under difficult retrieval conditions.

Dynamic evacuation routes for personnel on a naval ship

AbstractWe propose a dynamic escape route system for emergency evacuation of a naval ship. The system employs signals that adapt to the causative contingency and the crew's physical distribution about the ship. A mixed‐integer nonlinear programming model, with underlying network structure, optimizes the evacuation process. The network's nodes represent compartments, closures (e.g., doors and hatches) and intersections, while arcs represent various types of passageways. The objective function integrates two potentially conflicting factors: average evacuation time and the watertight and airtight integrity of the ship after evacuation. A heuristic solves the model approximately using a sequence of mixed‐integer linear approximating problems. Using data for a Spanish frigate, with standard static routes specified by the ship's designers, computational tests show that the dynamic system can reduce average evacuation times, nearly 23%, and can improve a combined measure of ship integrity by up to 50%. In addition, plausible design changes to the frigate yield further, substantial improvements. Published 2008 Wiley Periodicals, Inc. Naval Research Logistics 2008

Trends and challenges in sediment research 2008: the role of sediments in river basin management

This is the first editorial of an annual series. In it, we identify some of the forward-looking articles which appeared in JSS over the past two volumes and then continue to highlight recent global trends in sediment research. For the past 2 years, there has been an increase in publications which emphasize the fact that sediment is an integral and dynamic part of aquatic system and that it plays a major role in the hydrological, geomorphological, and ecological functioning of river basins. Here, disciplines such as slope geomorphology, fluvial sedimentology, coastal and marine sedimentology, and coastal management combine to assess interlinked issues of sediment production, transport, and accumulation (Perry and Taylor 2007; JSS book review by Forstner 2007). Central aspects are sediment dynamics and the interactions between sediment and pollutants in river systems (Westrich and Forstner 2007; JSS book review by Owens and Petticrew 2008). The river basin represents an appropriate scale for management because, in many cases, source control will be the optimal long-term solution: environmentally, socially, and economically (Salomons 2008). Climate changes are expected to change regional hydrology and cause changes in erosion, transport, and deposition of sediments; plausible land-use changes can be interfaced with natural science and socioeconomic models to assess the impact on sediment quality (Salomons 2005). In the EuroCat project (Salomons 2004), catchment changes and their impact on the coast were studied on seven systems covering all coastal types (except for fjords) in Europe and different socioeconomic settings. Many articles of the past two JSS volumes dealt with sediment toxicity studies and in particular with elucidating the complex mixture of potential hazardous compounds in sediments (JSS Subject Area Sediments, Section 1 ‘Sediment Quality and Impact Assessment’):

Colorectal Cancer (CRC) Screening with Optical Colonoscopy (Oc) vs. CT Colonography (CTC)

Purpose: CTC is recommended as one of the options for CRC screening by the U.S. Multi-Society Task Force on Colorectal Cancer. However, its cost-effectiveness (CE) compared with OC has not been proven in all studies. Furthermore, these CE analyses were based upon only polyp size, but not on polyp pathology, CTC radiation risk or quality-adjusted life years (QALYs). We performed a cost effectiveness analysis utilizing these factors to compare CTC and OC. Methods: For the base case, we used a hypothetical 50-year old person with an average risk of colon cancer who underwent first screening with one of the two strategies. All polyps detected on CTC would be referred for OC and approximately 75% of those referred would undergo OC due to differing adherence rates. We modeled a time horizon of 10 years and projected life expectancy. Effectiveness was measured as quality adjusted life years (QALY) and cancers detected or averted. Incremental cost-effectiveness ratios (ICERs) were calculated for cost per additional QALY gained, or cancer detected or averted. All polyps were divided into ≥ 10 mm, <10 mm high risk, <10 mm low risk and incident cancers. Transition probabilities from polyp to cancer to death, and test accuracies of CTC and OC were obtained from the literature review. Direct medical costs were estimated from Medicare reimbursements. Sensitivity analyses were performed for plausible variations in parameters. Cost and QALYs were discounted at 3%. Results: For the base case analysis, on average, for each additional cancer detected or averted, 321 people would need to be screened with OC as opposed to CTC. For each additional QALY, we found that the ICER for OC was $1,766 compared with CTC, when all polyps detected by CTC would be referred for OC/polypectomy. The ICER increased to $3,759 if only polyps > 10 mm were referred for OC (assuming a malignant potential for polyps < 10 mm). If no malignant potential is assumed for < 10 mm polyp, then the ICER increased to $42,449. The model was robust to plausible changes in parameters on sensitivity analysis for QALYs gained and cancers detected or averted. Conclusion: CRC screening with optical colonoscopy appears to be both more effective and more cost-effective than CTC.

Optimization of primary and secondary cervical cancer prevention strategies in an era of cervical cancer vaccination: A multi-regional health economic analysis

With the recent advent of cervical cancer vaccines, many questions relating to the best overall prevention methods for cervical disease are beginning to arise. A Markov model was used across five geographic regions (Canada, The Netherlands, Taiwan, UK, US) to examine the clinical benefits and cost-effectiveness of: (1) vaccination combined with screening, considering changes to screening-related parameters and (2) vaccination combined with screening, considering changes to screening policy. Given the assumptions used in this analysis, adding vaccination to current screening is likely to be cost-effective in the regions studied. When considering vaccination with several plausible changes to screening programmes, locations with the most frequent Papanicolaou smear testing may achieve the most efficiency gains by adopting a less frequent screening interval or incorporating HPV testing into their screening practices. Although it may be beneficial to change screening to maximize efficiency, the most cost-effective strategies for vaccination and screening combinations may not lead to the greatest reductions in cervical cancer; therefore such policy decisions may vary depending on region-specific goals. Finally, new screening paradigms such as primary HPV testing should be considered in future analyses.

Modeling neuromuscular effects of ankle foot orthoses (AFOs) in computer simulations of gait

Ankle foot orthoses (AFOs) provide immediate changes to gait kinematics and alter EMG-recorded muscle activity during gait; yet our understanding of neuromuscular adaptations while using AFOs remains incomplete. To address this, we have developed a tunable AFO model to predict torque from ankle angle and velocity and to identify plausible changes in muscle excitation and function in a walking simulation. Using a dynamometer in passive mode, we isolated flexion/extension torque of three polypropylene spring leaf AFOs at 5°/s, 30°/s and 120°/s, from which a model of AFO torque as a function of deformation angle, velocity and size was derived with predictive ability of R 2 > 0.9. The model coefficients did not vary linearly with size, illustrating the need to test AFO deformation response individually. We applied the tuned models to simulations of normal healthy gait to isolate AFO-induced neuromuscular changes. Compared to the No-AFO condition, AFO results show decreased net tibialis anterior excitation. Our results also show that net soleus excitation is not diminished with an AFO although soleus-induced ankle accelerations were reduced. With a tunable AFO model applied to walking simulations, we can quantify the contributions of muscle and orthosis to net joint torque and predict changes in neuromuscular control during walking.

More Sites or More Years? Optimal Study Design for Monitoring Fish Response to Watershed Restoration

AbstractEvery year in the Pacific Northwest, hundreds of stream restoration projects are implemented at great expense in the hope that they will increase salmonid abundance. Our understanding of how salmonids interact with their freshwater habitat has steadily improved, but we are still a long way from being able to reliably predict population‐level effects of individual projects. To determine whether these projects are in fact increasing salmonid abundance, we will need to implement restoration at the watershed scale, monitor the populations after the freshwater portion of their life history is completed, and replicate the experiment across multiple watersheds to produce results that can be generalized. Although there has been some progress in this direction, it has largely consisted of independent efforts at a relatively small scale. In this paper, we use smolt counts of coho salmon Oncorhynchus kisutch from streams in western Washington and Oregon, along with approximate restoration and monitoring costs, to estimate the most cost‐effective way of allocating monitoring effort between years and watersheds to allow detection of an average response to watershed‐scale restoration. We show that it is generally preferable to spread the available effort across more watershed pairs, unless the one‐time cost of adding a watershed pair is very high (e.g., when the cost of restoration is included). These results are sensitive to plausible changes in temporal and spatial variability and may change with different assumptions about response type, but they are derived using a logical, transparent process that incorporates available information.

Anti-Americanism and Electoral Politics in Korea

How people in foreign countries perceive the United States has been an enduring theme for students of international relations, as well as for foreign policy decision makers. Since the end of the Cold War, the United States has been exposed to broad criticism around the globe, not exclusively in Islamic countries, as represented currently in the U.S. mainstream press. In 2005, the Pew Global Attitudes Project Survey reported that anti-Americanism is deeper and broader now than at any time in modern history.1 As a result, a number of studies have attempted to explain the causes of increasing anti Americanism that might exacerbate existing problems in relationships between the United States and other countries. It is, however, notable that only a few studies have examined how anti American perception relates to electoral politics, which may give us clearer views regarding the nature of the antagonism and plausible foreign policy changes. The well-known scapegoating theory already has pointed out that electoral politics is deeply related to anti-Americanism. The theory claims that politicians might manipulate public perception of the United States if doing so would ensure their electoral success. Andrew Kohut argued, for example, that the overwhelming success of German Chancellor Gerhard Schroeder in the 2002 election was driven strongly by his electoral strategy to break with Wash ington over the war in Iraq.2 However, except for such anecdotal explana

Attitude and Knowledge Changes in Auxiliary Members: Short-term Primary Prevention Program on Eating Disorders

PURPOSE: The study examined the efficacy of a team-centered prevention program targeting eating disorders by assessing knowledge and attitude changes in collegiate auxiliary members (color guard, dance team, majorettes). METHODS: Samples from two auxiliary units at two Division I institutions in the Southeastern United States compromised control (n=19) and experimental (n=21) groups. A pre-existing primary prevention program served as treatment. Intervention components were supplementation, psychological measures, sports nutrition, and exercise. Eight 45-minute classroom sessions were delivered across 4-weeks. The Eating Disorder Inventory-3 and the Center for Epidemiological Studies Depression Scale assessed psychological traits and depression. Nutrition and disordered eating surveys assessed content knowledge. RESULTS: Experimental participants significantly improved nutrition knowledge (p≤0.01) and eating disorders (p=0.01) knowledge compared to the control group who demonstrated no significant difference. Compared to no significant changes for the control, the experimental groups had positive (beneficial) significant changes for: EDI-3 low selfesteem subscale (p=0.03), depressions levels (p≤0.01), drive for thinness (p=0.01), bulimia (p=0.02), body dissatisfaction (p=0.03), and maturity fears (p=0.02). CONCLUSIONS: This team approach prevention program effectively improved shortterm knowledge and eating disorder attitudes. While it is plausible behavioral changes would follow, future research should directly examine this possibility.

Relationships between human thirst, hunger, drinking, and feeding

There is a widely held view that hunger prompts feeding to ensure energy needs are met, while thirst cues drinking to address hydration requirements. However, recent changes in the nature of the food supply and eating patterns have raised questions about the functionality of these relationships with respect to maintaining energy balance. The increasing consumption of energy-yielding beverages and foods with diluted energy density, through the use of ingredients such as high-intensity sweeteners and fat replacers, poses new challenges to presumed homeostatic energy regulatory mechanisms. This review draws on findings from a recent observational study and other published evidence to explore whether shifts of food composition and use patterns may be disrupting relationships between thirst, hunger, drinking, and eating, resulting in positive energy balance (e.g., drinking low satiety, energy-yielding beverages in response to hunger). The observational study entailed collecting hourly appetitive ratings and dietary recalls from 50 adults for seven consecutive days. These data reveal a clear bimodal daily hunger pattern, whereas thirst is stronger and more stable throughout the day. Further, approximately 75% of fluid intake occurs peri-prandially, with the majority derived from energy-yielding beverages. While there is published evidence that drinking is responsive to feeding, support for the view that drinking is the more tightly regulated behavior is stronger. Our data indicates that, due to a number of plausible factors, neither absolute values nor changes of hunger or thirst are strong predictors of energy intake. However, it is proposed that stable, high thirst facilitates drinking, and with the increased availability and use of energy-yielding beverages that have low satiety properties, can promote positive energy balance. There are marked individual differences in mean daily hunger and thirst ratings with unknown implications for energy balance.

Trastuzumab

Trastuzumab (Herceptin) is a monoclonal antibody approved for the treatment of breast cancer that overexpresses human epidermal growth factor receptor 2 (HER2). Well designed clinical trials in women with early breast cancer have demonstrated that 1 years' therapy with adjuvant intravenous trastuzumab (a loading dose followed by 6 mg/kg every 3 weeks or 2 mg/kg weekly) significantly improves disease-free survival and overall survival compared with observation (subsequent to chemotherapy) or chemotherapy alone in women with HER2-positive disease. In the HERA trial, disease-free survival was estimated to improve by 6.3% at 3 years in the trastuzumab group compared with the observation group. Trastuzumab is generally well tolerated. The most common adverse events are infusion-related symptoms, such as fever and chills, which usually occur with administration of the first dose. Cardiotoxicity occurs in a small proportion of patients receiving trastuzumab, particularly when coadministered with anthracyclines, and cardiac assessment is recommended for all patients at baseline and at 3-monthly intervals. In modelled cost-effectiveness analyses based on data from clinical trials in patients with HER2-positive early breast cancer, adjuvant trastuzumab was predicted to be cost effective from a healthcare payer or societal perspective in several countries. Incremental costs per QALY or life-year gained with trastuzumab administered subsequent to or concurrent with chemotherapy compared with chemotherapy alone were consistently within accepted local thresholds for cost effectiveness. Sensitivity analyses demonstrated that these results remained generally robust to plausible changes in key model assumptions. In conclusion, in patients with HER2-positive early breast cancer, the addition of adjuvant trastuzumab is clinically effective in improving disease-free survival. Available pharmacoeconomic data from several countries, despite some inherent limitations, support the use of adjuvant trastuzumab for 1 year as a cost-effective treatment relative to chemotherapy alone in this patient population.

Temperature change signals in northern Canada: convergence of statistical downscaling results using two driving GCMs

AbstractCoarse resolution global climate models (GCMs) have inherent difficulty simulating a reliable climate regime in coastal areas, as in northern Canada, where sea ice and snow cover are highly sensitive to fine‐scale climate forcings. As a result, strong biases are present in GCM temperature regimes in this region, and the direct use of raw‐GCM climate change signals at the local scale is problematic. However, fine resolution climate change information for use in impact studies can be obtained via statistical downscaling (SD) methods. This study investigates the regression‐based SDSM model with respect to its potential to simulate reliable and plausible changes in mean values as well as probabilities of extreme temperatures, in some specific locations in northern Canada. Four sets of independent climate predictors, from the outputs of two GCMs (i.e. CGCM2 and HadCM3) and using two SRES emission scenarios (i.e. A2 and B2), are used by the SDSM model to construct climate scenario information for this region over the period 2070–2099. The results demonstrate that the SD model is able to capture the major part of the temperature change signal, with a plausible climatic regime for higher warming in winter than in summer and in A2 than in B2 runs. The combination of relevant atmospheric predictors in the SD process is able to take into account most key factors of the temperature change signal, with strong convergence in the magnitude and the timing of the changes in all results. The downscaling signals are more consensual and physically‐plausible in comparison with the raw GCM anomalies, with relatively better skill using HadCM3 predictors than those from CGCM2. The study also confirms that scrupulous analysis of the climate change regime and its temporal and spatial distribution at the scale of interest is essential for it to be useful in impact studies. Copyright © 2007 Crown in the right of Canada. Published by John Wiley &amp; Sons, Ltd

Environmental change and the phenology of European aphids

AbstractAphids, because of their short generation time and low developmental threshold temperatures, are an insect group expected to respond particularly strongly to environmental changes. Forty years of standardized, daily data on the abundance of flying aphids have been brought together from countries throughout Europe, through the EU Thematic Network ‘EXAMINE’. Relationships between phenology, represented by date of first appearance in a year in a suction trap, of 29 aphid species and environmental data have been quantified using the residual maximum likelihood (REML) methodology. These relationships have been used with climate change scenario data to suggest plausible changes in aphid phenology. In general, the date of first record of aphid species in suction traps is expected to advance, the rate of advance varying with location and species, but averaging 8 days over the next 50 years. Strong relationships between aphid phenology and environmental variables have been found for many species, but they are notably weaker in species living all year on trees. Canonical variate analysis and principal coordinate analysis were used to determine ordinations of the 29 species on the basis of the presence/absence of explanatory variables in the REML models. There was strong discrimination between species with different life cycle strategies and between species feeding on herbs and trees, suggesting the possible value of trait‐based groupings in predicting responses to environmental changes.

An oceanic fixed nitrogen sink exceeding 400 Tg N a&amp;lt;sup&amp;gt;−1&amp;lt;/sup&amp;gt; vs the concept of homeostasis in the fixed-nitrogen inventory

Abstract. Measurements of the N2 produced by denitrification, a better understanding of non-canonical pathways for N2 production such as the anammox reaction, better appreciation of the multiple environments in which denitrification can occur (e.g. brine pockets in ice, within particles outside of suboxic water, etc.) suggest that it is unlikely that the oceanic denitrification rate is less than 400 Tg N a−1. Because this sink term far exceeds present estimates for nitrogen fixation, the main source for oceanic fixed-N, there is a large apparent deficit (~200 Tg N a−1) in the oceanic fixed-N budget. The size of the deficit appears to conflict with apparent constraints of the atmospheric carbon dioxide and sedimentary δ15N records that suggest homeostasis during the Holocene. In addition, the oceanic nitrate/phosphate ratio tends to be close to the canonical Redfield biological uptake ratio of 16 (by N and P atoms) which can be interpreted to indicate the existence of a powerful feed-back mechanism that forces the system towards a balance. The main point of this paper is that one cannot solve this conundrum by reducing the oceanic sink term. To do so would violate an avalanche of recent data on oceanic denitrification. A solution to this problem may be as simple as an upwards revision of the oceanic nitrogen fixation rate, and it is noted that most direct estimates for this term have concentrated on nitrogen fixation by autotrophs in the photic zone, even though nitrogen fixing genes are widespread. Another simple explanation may be that we are simply no longer in the Holocene and one might expect to see temporary imbalances in the oceanic fixed-N budget as we transition from the Holocene to the Anthropocene in line with an apparent denitrification maximum during the Glacial-Holocene transition. Other possible full or partial explanations involve plausible changes in the oceanic nitrate/phosphate and N/C ratios, an oceanic phosphorus budget that may also be in deficit, and oscillations in the source and sink terms that are short enough to be averaged out in the atmospheric and geologic records, but which could, perhaps, last long enough to have significant impacts.

A geodetic study of the 2003 January 22 Tecomán, Colima, Mexico earthquake

We use coseismic displacements and aftershock information from Global Positioning System (GPS) measurements at 27 sites in western Mexico and a 12-station local seismic network to determine the characteristics of the 2003 January 22 M_w = 7.2 subduction thrust earthquake near Tecoman, Colima, Mexico. Estimates of the earthquake moment, slip direction and best-fitting slip distribution are derived by optimizing the fit to the GPS displacements for a 3-D finite element mesh that simulates the study area. The calculated moment release is 9.1 × 10^(19) N m (M_w = 7.2) , with maximum slip of 2 m at a depth of 24 km and a maximum rupture depth of 35–40 km. The inversion indicates that coseismic rupture extended downdip from depths of 9 to 40 km along a 80 km along-strike region that is bounded by the edges of the Manzanillo Trough. The optimal solution is robust with respect to plausible changes in the subduction interface geometry and differing subsets of the data. A comparison of the cumulative post-seismic slip that can be inferred separately from earthquake aftershocks and GPS measurements within a year of the earthquake indicates that 95 per cent or more of the post-seismic deformation was aseismic. Near-term post-seismic measurements indicate that slip propagated downdip to areas of the subduction interface beneath the coastline within days following the earthquake, as also occurred after the nearby M_w = 8.0 Colima-Jalisco subduction earthquake in 1995. The similar behaviours and locations of the 1995/2003 earthquake sequence to two earthquakes in June of 1932 suggests that thrust earthquakes along the subduction interface northwest of the Manzanillo Trough may trigger earthquakes in the vicinity of the Manzanillo Trough; however, our modelling of Coulomb stress changes caused by the 1995 earthquake indicate that it induced only modest unclamping of the subduction interface in the vicinity of the Tecoman rupture. In addition, GPS measurements indicate that elastic shortening characterized areas onshore from the Tecoman rupture from mid-1997 up until the time of the rupture, consistent with progressively stronger clamping of the subduction interface during this period. This precludes any obvious triggering relationship with the 1995 earthquake. The apparent coincidence of the edge of both the 1932 and 1995/2003 rupture sequences with the edge of the Manzanillo Trough may indicate that the trough is a mechanical barrier to along-strike rupture propagation. This implies a limit to the area of potential slip and hence rupture magnitude during future large earthquakes in this region.

Summer water deficit variability controls on peatland water-table changes: implications for Holocene palaeoclimate reconstructions

Interpretation of proxy-climate records depends on a thorough understanding of the proxy-climate relationship. Peatland surface wetness records have been interpreted as reflecting changes between cool and/or wet conditions and warm and/or dry conditions. This paper analyses a high-resolution record of reconstructed water-table changes based on testate amoebae analysis in relation to instrumental weather records since AD 1775. Replicate peat records are reconciled by multiple chronological techniques and tuning, and demonstrate that the reconstructions preserve many replicable high-frequency changes. Water-table variability is highly correlated with the total seasonal moisture deficit (precipitation—evapotranspiration, P-E) expressed as the sum of all months with negative P-E. The reconstructed water-table record reflects antecedent periods of 5 or 10 years (maximum r2 = 52.4%) and proxy bog surface wetness records can therefore be interpreted as reflecting the length and intensity of the summer water deficit period. Response surfaces of the summer deficit in relation to temperature and precipitation variability support the hypothesis that the summer deficit is determined by summer precipitation in midlatitude oceanic peatlands and that summer temperature plays a greater but still subsidiary role in higher latitude, continental settings. These relationships apply for all plausible past Holocene climate changes and future twenty-first century climate scenarios. Non-linear responses to longer-term climate states prevent the direct application of a calibration of the reconstructed water-table records to infer quantitative estimates of climate variables. Models that combine peat accumulation, mire growth and hydrological processes are required to undertake this task.

Comparison of hydrological impacts of climate change simulated by six hydrological models in the Dongjiang Basin, South China

Large differences in future climatic scenarios found when different global circulation models (GCMs) are employed have been extensively discussed in the scientific literature. However, differences in hydrological responses to the climatic scenarios resulting from the use of different hydrological models have received much less attention. Therefore, comparing and quantifying such differences are of particular importance for the water resources management of a catchment, a region, a continent, or even the globe. This study investigates potential impacts of human-induced climate change on the water availability in the Dongjiang basin, South China, using six monthly water balance models, namely the Thornthwaite–Mather (TM), Vrije Universitet Brussel (VUB), Xinanjiang (XAJ), Guo (GM), WatBal (WM), and Schaake (SM) models. The study utilizes 29-year long records of monthly streamflow and climate in the Dongjiang basin. The capability of the six models in simulating the present climate water balance components is first evaluated and the results of the models in simulating the impact of the postulated climate change are then analyzed and compared. The results of analysis reveal that (1) all six conceptual models have similar capabilities in reproducing historical water balance components; (2) greater differences in the model results occur when the models are used to simulate the hydrological impact of the postulated climate changes; and (3) a model without a threshold in soil moisture simulation results in greater changes in model-predicted soil moisture with respect to alternative climates than the models with a threshold soil moisture. The study provides insights into the plausible changes in basin hydrology due to climate change, that is, it shows that there can be significant implications for the investigation of response strategies for water supply and flood control due to climate change.

Atorvastatin

Atorvastatin is a lipid-lowering agent that has been evaluated in a number of primary and secondary intervention studies. In the primary prevention trials ASCOT-LLA and CARDS, atorvastatin 10 mg/day significantly reduced cardiovascular events compared with placebo. A prospectively conducted economic analysis of the 3.3-year ASCOT-LLA trial showed that atorvastatin was associated with incremental cost-effectiveness ratios (ICERs) of euro11,693 (UK) and euro12,673 (Sweden) per event avoided (2002 values). Longer-term modelled analyses using data from CARDS showed ICERs of euro8046 (Spain) and 6471pound (UK) per QALY gained (2003/2004 values), and a US analysis showed atorvastatin was dominant versus no statin when modelled over the lifetime of a representative US diabetic primary prevention population. In a modelled analysis based on results of the IDEAL trial, which showed significant reductions in cardiovascular endpoints with high-dose atorvastatin (80 mg/day) compared with conventional-dose simvastatin in patients with stable coronary heart disease, ICER values were below the commonly used cost-effectiveness threshold of euro50,000 per QALY gained in Norway, Sweden and Denmark, but were above this threshold in Finland (2005 values). A modelled US analysis that also included data from IDEAL and other sources showed an ICER of $US33,400 per QALY gained, assuming the incremental difference in acquisition cost between high-dose atorvastatin and conventional-dose simvastatin was $US1.40/day (2005 value). Most cost-effectiveness analyses with atorvastatin in patients with acute coronary syndrome used data from the 16-week MIRACL study, which showed a significant reduction in cardiovascular events with high-dose atorvastatin compared with placebo. Analyses were conducted in North America and Europe and showed that 31-86% of the acquisition cost of high-dose atorvastatin was offset by reductions in costs associated with cardiovascular events. Across five countries, ICER values ranged from approximate $US850 to $US4100 per event avoided (2000/2001 values). Another analysis conducted in the US used longer-term data and showed that high-dose atorvastatin versus conventional-dose statin was associated with an ICER of $US12,900 per QALY gained, assuming the daily difference in acquisition cost was $US1.40 (2005 value). In conclusion, atorvastatin has demonstrated beneficial effects on various cardiovascular endpoints in large, well designed primary and secondary intervention trials. These benefits in moderate- to high-risk patients were achieved at a relatively low incremental cost and, across the economic analyses, a substantial proportion of atorvastatin acquisition costs was offset by reductions in healthcare resource use associated with cardiovascular events. Cost-effectiveness analyses based on major clinical trials comparing atorvastatin with placebo, usual medical care, simvastatin or pravastatin have generally shown that atorvastatin is associated with favourable ICER values, often well below commonly used cost-effectiveness thresholds. These modelled analyses have the inherent limitation that projecting long-term outcomes beyond the time period of a clinical trial imparts a degree of uncertainty to the results. Nevertheless, while some findings were sensitive to changes in model assumptions, such as the long-term benefits of statin therapy, most sensitivity analyses showed that results of the base-case analyses were robust to plausible changes in key parameters. Although a clear pattern is not evident from available data, intuitively, the value of atorvastatin would be expected to increase with the patient's risk for serious cardiovascular events.