Pessimistic Assumptions Research Articles

Modelling the Cost-Effectiveness of Alcohol Screening and Brief Interventions in Primary Care in England

To estimate the cost-effectiveness and resourcing implications of universal alcohol screening and brief intervention (SBI) programmes in primary care in England. This was a health economic model, combining evidence of the effectiveness and health care resource requirements of SBI activities with existing epidemiological modelling of the relationship between alcohol consumption and health harms. Screening patients on registration with a family doctor would steadily capture ~40% of the population over a 10-year programme; screening patients at next primary care consultation would capture 96% of the population over the same period, but with high resourcing needs in the first year. The registration approach, delivered by a practice nurse, provides modest cost savings to the health care system of £120 m over 30 years. Health gains over the same period amount to 32,000 quality-adjusted life years (QALYs). This SBI programme still appears cost-effective (at £6900 per QALY gained) compared with no programme, under pessimistic effectiveness assumptions. Switching to a consultation approach, delivered by a doctor, would incur an incremental net cost of £108 m, with incremental health gains equivalent to 92,000 QALYs, giving an incremental cost-effectiveness ratio of £1175 per QALY gained compared with current practice. A universal programme of alcohol SBI in primary care is estimated to be cost-effective, under all but the most pessimistic assumptions for programme costs and effectiveness. Policymakers should ensure that SBI programmes are routinely evaluated and followed up, given the substantial uncertainty over the effects of many of the implementation details.

Cost-Effectiveness of Tenofovir Instead of Zidovudine for Use in First-Line Antiretroviral Therapy in Settings without Virological Monitoring

BackgroundThe most recent World Health Organization (WHO) antiretroviral treatment guidelines recommend the inclusion of zidovudine (ZDV) or tenofovir (TDF) in first-line therapy. We conducted a cost-effectiveness analysis with emphasis on emerging patterns of drug resistance upon treatment failure and their impact on second-line therapy.MethodsWe used a stochastic simulation of a generalized HIV-1 epidemic in sub-Saharan Africa to compare two strategies for first-line combination antiretroviral treatment including lamivudine, nevirapine and either ZDV or TDF. Model input parameters were derived from literature and, for the simulation of resistance pathways, estimated from drug resistance data obtained after first-line treatment failure in settings without virological monitoring. Treatment failure and cost effectiveness were determined based on WHO definitions. Two scenarios with optimistic (no emergence; base) and pessimistic (extensive emergence) assumptions regarding occurrence of multidrug resistance patterns were tested.ResultsIn the base scenario, cumulative proportions of treatment failure according to WHO criteria were higher among first-line ZDV users (median after six years 36% [95% simulation interval 32%; 39%]) compared with first-line TDF users (31% [29%; 33%]). Consequently, a higher proportion initiated second-line therapy (including lamivudine, boosted protease inhibitors and either ZDV or TDF) in the first-line ZDV user group 34% [31%; 37%] relative to first-line TDF users (30% [27%; 32%]). At the time of second-line initiation, a higher proportion (16%) of first-line ZDV users harboured TDF-resistant HIV compared with ZDV-resistant viruses among first-line TDF users (0% and 6% in base and pessimistic scenarios, respectively). In the base scenario, the incremental cost effectiveness ratio with respect to quality adjusted life years (QALY) was US$83 when TDF instead of ZDV was used in first-line therapy (pessimistic scenario: US$ 315), which was below the WHO threshold for high cost effectiveness (US$ 2154).ConclusionsUsing TDF instead of ZDV in first-line treatment in resource-limited settings is very cost-effective and likely to better preserve future treatment options in absence of virological monitoring.

Dependency of global primary bioenergy crop potentials in 2050 on food systems, yields, biodiversity conservation and political stability

The future bioenergy crop potential depends on (1) changes in the food system (food demand, agricultural technology), (2) political stability and investment security, (3) biodiversity conservation, (4) avoidance of long carbon payback times from deforestation, and (5) energy crop yields. Using a biophysical biomass-balance model, we analyze how these factors affect global primary bioenergy potentials in 2050. The model calculates biomass supply and demand balances for eleven world regions, eleven food categories, seven food crop types and two livestock categories, integrating agricultural forecasts and scenarios with a consistent global land use and NPP database. The TREND scenario results in a global primary bioenergy potential of 77EJ/yr, alternative assumptions on food-system changes result in a range of 26–141EJ/yr. Exclusion of areas for biodiversity conservation and inaccessible land in failed states reduces the bioenergy potential by up to 45%. Optimistic assumptions on future energy crop yields increase the potential by up to 48%, while pessimistic assumptions lower the potential by 26%. We conclude that the design of sustainable bioenergy crop production policies needs to resolve difficult trade-offs such as food vs. energy supply, renewable energy vs. biodiversity conservation or yield growth vs. reduction of environmental problems of intensive agriculture.

Treatment as prevention

The understanding that antiretroviral treatment prevents HIV transmission through suppression of viral load provides significant new opportunities in HIV prevention. However, knowledge of efficacy is only a first step to having an impact on the spread of HIV at a population level, the ultimate goal of all primary prevention modalities. This review explores what we know about treatment as prevention and how it could be used as a tool, as part of a combination approach, in the global response to HIV. Efficacy data show that treatment as prevention works at high levels in trial conditions in stable serodiscordant couples; a finding that can reasonably be generalized to other populations at risk of transmitting the virus. Modelling shows that treatment as prevention should have an impact, but the extent of this depends primarily upon whether optimistic or pessimistic assumptions are made about the programmatic use of antiretrovirals (ARVs). We describe research questions that need to be addressed in developing optimal programmatic public health treatment strategies including how best to target and implement the use of treatment as prevention, how to balance the needs of treatment for the individual patients' clinical benefit against population level benefits, and how to create programmes that are able to link people to and retain them in care.

Study of the Cost-Benefit Analysis of Electronic Medical Record Systems in General Hospital in China

Electronic medical record (EMR) systems have been proposed as technology to improve the quality of patient care, decrease medical errors, control and reduce medical expenditure, however the financial effects have not yet been as well documented in China. We presented a net financial cost-benefit analysis of implementing electronic medical record systems in general hospital in China. The data, which were obtained from studies of the general hospital and the published literature, collected from 15 consecutive fiscal months from May 1, 2009 to August 30, 2010. We performed a perspective cost-benefit study to analyze the financial effects of EMR system implementing. The reference strategy for comparisons was the traditional paper-based medical record. The net financial benefits or costs for a 6-year period were calculated. All data were adjusted for inflation. The totally assessed net benefit from implementing an EMR system for a 6-year period was $559,025 in the general hospital. Benefits accrue primarily from savings in new medical record creation, decreased full-time-equivalent (FTE) employees, saving of adverse drug events (ADEs) and dose errors, improved charge capture and decreased billing errors. In this model, the time of return on investment is 3.00 years. In one-way sensitivity analysis, the model was most sensitive in new medical record creation; the net benefit varied from $398,057 to $719,992. The five-way sensitivity analysis with the most pessimistic and optimistic assumptions showed results ranging from a $76,970 net cost to a $1,062,122 net benefit; the pessimistic time of return on investment is 5.38 years. An EMR system cost-benefit analysis can rapidly demonstrate a positive return on investment when implemented in hospitals. The magnitude of the return is sensitive to several key factors.

The Impact of Changes in Second Pension Pillars on Public Finances in Central and Eastern Europe

This paper studies the impact of recent changes in second pension pillars of three Central and Eastern European Countries on the deficit and implicit debt of their full pension systems. The paper seeks to answer the following questions: what is the impact on the sustainability of Poland’s pension system of the decrease in the pension contribution going to the second pension pillar from 7.3% to 2.3% in 2011; what are the implications of the recent changes on gross replacement rates; does the weakening of the Polish second pension system have a different impact on pension system sustainability than a similar move in a Hungarian-style pension system with a defined-benefit first pillar and how does Estonia’s temporary decrease in pension contributions compensated by temporarily higher future rates affect pension sustainability in that country. The simulation results show that in our baseline scenario the Polish move would permanently lower future pension-system debt, chiefly as a result of a cut in replacement rates. But using a combination of pessimistic assumptions including strong population ageing, low real wage growth and a high indexation of existing pension benefits, coupled with bringing in tax expenditures related to the third voluntary pension pillar and an increase in the share of minimum pensions leads to higher pension system deficits and eventually more public debt at a very long horizon. The simulations also suggest that the Hungarian pension reversal reduces deficit and debt only temporarily, mainly because of Hungary’s costly defined-benefit first pension pillar: the weakening of the second pillar is tantamount to swapping low current replacement rates (in the defined-contribution second pillar) against high future replacement rates in the defined-benefit first pension pillar. Finally, results show that the Estonian move will increase public debt only very moderately in the long run, even though this result is sensitive to the effective interest rate on public debt.

Potential impact and cost-effectiveness of multi-biofortified rice in China

Biofortification, that is, improving the micronutrient content of staple foods through crop breeding, could be a pro-poor, pro-rural, agriculture-based intervention to reduce the health burden of micronutrient malnutrition. While the potential cost-effectiveness of crops biofortified with single micronutrients was shown in previous research, poor people often suffer from multiple micronutrient deficiencies, which should be accounted for in biofortification initiatives. This study is the first to estimate the potential health benefits and cost-effectiveness of multi-biofortification. Rice with enhanced provitamin A, zinc, iron and folate concentrations is used as a concrete example. The research is conducted for China, the largest rice producer in the world, where micronutrient malnutrition remains a major public health problem. Using the DALY (disability-adjusted life year) framework, the current annual health burden of the four micronutrient deficiencies in China is estimated at 10.6 million DALYs. Introducing multi-biofortified rice could lower this burden by up to 46%. Given the large positive health impact and low recurrent costs of multi-biofortification, this intervention could be very cost effective: under optimistic assumptions, the cost per DALY saved would be around US$ 2; it would stay below US$ 10 even under pessimistic assumptions.

Training providers in hypertension guidelines: Cost-effectiveness evaluation of a continuing medical education program in South Carolina

Translation of published guidelines to clinical practice through continuing medical education (CME) can be effective at changing provider practice patterns and patient outcomes. Yet, cost-effectiveness analyses of CME interventions are rare. This study analyzed the cost-effectiveness of a CME program for improving patient hypertension outcomes relative to usual care. A CME, conducted by the Carolinas and Georgia chapter of the American Society of Hypertension, the Medical University of South Carolina, and the Heart Disease and Stroke Prevention Division of the South Carolina Department of Health and Environmental Control, trained primary care providers in evidence-based guidelines for hypertension prevention and control. A cost-effectiveness simulation model was created with inputs from primary data collection of program costs and secondary data analysis of the Hypertension Initiative Database for years 2000 through 2008. The data analysis consisted of a convenience sample of 8,183 patients in the Hypertension Initiative Database who saw a CME-trained provider at least once before and after the provider's training. Control patients saw providers who did not attend a CME program and were matched to CME patients using propensity score matching. Incremental life-years gained (LYG) for CME compared with no intervention were 0.003 per patient. The incremental cost-effectiveness ratio was $39,494 ($19,184-$73,864) per LYG under optimistic assumptions and $54,755 ($32,423-$95,728) per LYG under pessimistic assumptions. These results were most sensitive to changes in the effectiveness of the intervention on systolic blood pressure. The intervention is likely a cost-effective strategy to address hypertension in a real-world setting and can serve as a model for future innovations in hypertension prevention.

Constraining properties of the black hole population using LISA

LISA will detect gravitational waves from tens to hundreds of systems containing black holes with mass in the range 104 M⊙–107 M⊙. Black holes in this mass range are not well constrained by current electromagnetic observations, so LISA could significantly enhance our understanding of the astrophysics of such systems. In this paper, we describe a framework for combining LISA observations to make statements about massive black hole populations. We summarize the constraints that LISA observations of extreme-mass-ratio inspirals might be able to place on the mass function of black holes in the LISA range. We also describe how LISA observations can be used to choose between different models for the hierarchical growth of structure in the early Universe. We consider four models that differ in their prescription for the initial mass distribution of black hole seeds, and in the efficiency of accretion onto the black holes. We show that with as little as 3 months of LISA data, we can clearly distinguish between these models, even under relatively pessimistic assumptions about the performance of the detector and our knowledge of the gravitational waveforms.

Beijing 2008 olympic games meant danger for the health of athletes? Monitoring of air pollution during games of XXIX olympiade by PM10

There has been extensive debate about the impact of air pollution before Olympic games 2008 in Beijing and its influence on health and/or performance of athletes. BOCOG and Chinese authorities...

“Pasiones”, identidades colectivas y deliberación: los retos planteados por la democracia agonística

Theorists of agonistic democracy assume that the deliberative ideal fails to consider seriously enough the role of passions and collective identities in public life. The aim of this paper is to reconstruct this critique as formulated by Chantal Mouffe, and clarify the drawbacks that make it ultimately futile. More precisely, it will be argued that such a critique presupposes an unsatisfactory notion of reason. Furthermore, it is built upon some anthropologically pessimistic assumptions that, in the final analysis, are theoretically abstruse.

Quantum black holes with charge, color and spin at the LHC

In low-scale gravity scenarios, quantum black holes could be produced at the Large Hadron Collider (LHC) provided the Planck scale is not higher than a few TeV. Based on fundamental principles and a few basic assumptions, we have constructed a model for quantum black hole production and decay in proton–proton collisions. By performing a particle-level simulation at LHC energies, we have estimated cross sections and branching fractions for final-state particle topologies that would uniquely identify quantum black holes in LHC detectors. If the Planck scale is about a TeV, even with the most pessimistic assumptions, the rates for quantum black hole production are estimated to be above backgrounds, and some of the final-particle states are not found in standard model processes. Our results could form the starting point for a detailed investigation of quantum black holes by the LHC experiments.

Relic gravitational waves in light of the 7-year Wilkinson Microwave Anisotropy Probe data and improved prospects for the Planck mission

The new release of data from Wilkinson Microwave Anisotropy Probe improves the observational status of relic gravitational waves. The 7-year results enhance the indications of relic gravitational waves in the existing data and change to the better the prospects of confident detection of relic gravitational waves by the currently operating Planck satellite. We apply to WMAP7 data the same methods of analysis that we used earlier [W. Zhao, D. Baskaran, and L.P. Grishchuk, Phys. Rev. D 80, 083005 (2009)] with WMAP5 data. We also revised by the same methods our previous analysis of WMAP3 data. It follows from the examination of consecutive WMAP data releases that the maximum likelihood value of the quadrupole ratio $R$, which characterizes the amount of relic gravitational waves, increases up to $R=0.264$, and the interval separating this value from the point $R=0$ (the hypothesis of no gravitational waves) increases up to a $2\sigma$ level. The primordial spectra of density perturbations and gravitational waves remain blue in the relevant interval of wavelengths, but the spectral indices increase up to $n_s =1.111$ and $n_t=0.111$. Assuming that the maximum likelihood estimates of the perturbation parameters that we found from WMAP7 data are the true values of the parameters, we find that the signal-to-noise ratio $S/N$ for the detection of relic gravitational waves by the Planck experiment increases up to $S/N=4.04$, even under pessimistic assumptions with regard to residual foreground contamination and instrumental noises. We comment on theoretical frameworks that, in the case of success, will be accepted or decisively rejected by the Planck observations.

SRAM FPGA Reliability Analysis for Harsh Radiation Environments

This paper investigates the viability of deploying SRAM-based FPGAs into harsh Earth-orbit environments. A reliability model is presented for estimating the MTTF of SRAM FPGA designs in specific orbits and orbit conditions. The model requires orbit- and condition-specific SEU rates and design-specific estimates of the probability of failure during a single scrubbing period. Probability of failure estimates are reported for several FPGA designs from both fault-injection and accelerator experiments. The model also includes a method for estimating composite mean time to failure (MTTF) that incorporates all orbit conditions over a solar cycle. Despite using pessimistic assumptions, the results from this model suggest that SRAM FPGA designs protected by TMR and scrubbing operate very reliably in a LEO orbit and surprisingly well in ¿harsh¿ orbits.

DVFS Algorithm Exploiting Correlation in Runtime Distribution

Dynamic voltage and frequency scaling (DVFS) is an effective method to achieve low power design. In our work, we present an analytical DVFS method which judiciously exploits correlation information in runtime distribution while satisfying deadline constraints. The proposed method overcomes the previous distribution-aware DVFS method [2] which has pessimistic assumption on which runtime distributions are independent. Experimental results show the correlation-aware DVFS offers 13.3% energy reduction compared to existing distribution-aware DVFS [2].

Feasible climate targets: The roles of economic growth, coalition development and expectations

The analysis presented here follows the design specified by the Energy Modeling Forum (EMF) Transition Scenarios study on achieving climate stabilization goals with delayed participation by developing countries. We use the MERGE model to evaluate the core EMF scenarios for both the international and the US-specific studies. Our results indicate that a radiative forcing target equivalent to 450 ppmv CO 2-e cannot be met even allowing for full participation and overshoot during the entire 21st century. With delayed participation of developing countries, a target of 550 ppmv CO 2-e is only attainable with pessimistic assumptions about economic growth, and even then only at very high cost. A target of 650 ppmv CO 2-e can be met with delayed participation for a more affordable cost. We highlight sensitivities to the core scenarios in two key dimensions: (i) the effect of the unfolding global financial crisis on the rate of economic growth and (ii) the willingness of initially non-participating countries to agree at the beginning of the next commitment period (i.e. 2012) to join the coalition at a pre-specified date in the future. We find that while the recession does not fundamentally change the crucial role of developing country involvement, advance agreement on their part to future targets could substantially reduce costs for all countries.

An Analytical Dynamic Scaling of Supply Voltage and Body Bias Based on Parallelism-Aware Workload and Runtime Distribution

Dynamic voltage and frequency scaling (DVFS) for a parallel software program is crucial for lowering the ever-increasing power consumption of multiprocessor systems-on-chips (SoCs). In this paper, we propose an analytical DVFS method that judiciously exploits slack by considering the varying parallelism over each path in a task graph. The proposed method overcomes the conventional pessimistic assumption on the remaining workload, i.e., worst-case execution cycle. It yields minimum average energy consumption by utilizing the runtime distribution of a software program while satisfying the deadline constraints. The proposed method tackles leakage power consumption as well as dynamic power consumption by combined <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dd</sub> / <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">bb</sub> scaling. Compared to conventional method , experimental results show that the proposed method provides up to 49.20% energy reduction for a set of synthetic task graphs and yields 23.93% and 27.15% energy reductions for two multimedia applications, namely, the H.264 encoder and decoder, respectively.

Effect of Smoking Cessation Advice on Cardiovascular Disease

Performance measures and guidelines encourage physicians to advise smokers to quit. The effect of these efforts on the morbidity, mortality, and cost of cardiovascular disease is not known. This article analyzes the effects of offering smoking cessation advice in the US population. The Archimedes model is used to simulate several clinical trials in which basic advice and medication advice are offered and to calculate the rates of myocardial infarctions, congestive heart disease deaths, strokes, life years, quality-adjusted life years (QALYs), costs, and cost/ QALY. The simulated population is a representative sample of the US population drawn from the Third National Health and Nutrition Survey conducted just before the performance measures and guidelines were introduced. The results show that offering basic advice and medication advice can prevent about 13% and 19% of myocardial infarctions and strokes, respectively. The 30-year cost/QALY is approximately $3000 less than the base-case assumptions and less than $10 000 under pessimistic assumptions.

Combining system scenarios and configurable memories to tolerate unpredictability

Process variability and the dynamism of new applications increase the uncertainty of embedded systems and force designers to use pessimistic assumptions, which have a tremendous impact on both the performance and energy consumption of their memory organizations. In this article we introduce an experimental framework which tries to mitigate the effects of both sources of unpredictability. At compile time, an extensive profiling helps us to detect system scenarios and bounds application dynamism. At the organization level, we incorporate a heterogeneous memory architecture composed by several configurable memories. A calibration process and a runtime control system adapt the platform to the current application needs. Our approach manages to reduce significantly the energy overhead associated to both variability and application dynamism (up to 60%, according to our simulations) without compromising the timing constraints existing in our target domain of dynamic periodic multimedia applications.

Is econometrics useful for private policy making? A case study of replacement policy at an auto rental company

The goal of this paper is to illustrate the potential usefulness of econometrics as a tool to assist private policy makers. We provide a case study and detailed econometric analysis of the automobile replacement policy adopted by a large car rental company. Unlike public policy making–where the benefits from using econometric models and “science-based” approaches to policy making are hard to quantify because the outcomes of interest are typically subjective quantities such as “social welfare”–in the case of firms there is an objective, easily quantifiable criterion for judging whether policy A is better than policy B: profits. We introduce and estimate an econometric model of the rental histories of individual cars in the company’s fleet. Via stochastic simulations, we show that the model provides a good approximation to the company’s actual operations. In particular, the econometric model is able to reproduce the extraordinarily high rates of return that the company obtains on its rental cars, with average internal rates of return between purchase and sale of approximately 50%. However, the econometric model can simulate outcomes under a range of counterfactual vehicle replacement policies. We use the econometric model to simulate the profitability of an alternative replacement policy under pessimistic assumptions about the rate maintenance costs would increase and rental rates would have to be decreased if the company were to keep its rental cars longer than it does under the status quo. Depending on the vehicle type, we find that the company’s expected discounted profits would be between 6% to over 140% higher under the suggested alternative operating strategy where vehicles are kept longer and rental rates of older vehicles are discounted to induce customers to rent them. The company found this analysis to be sufficiently convincing that it undertook an experiment to verify the predictions of the econometric model.