Bounded-width polynomial-size branching programs recognize exactly those languages in NC1

AbstractWe show that any language recognized by an NC1 circuit (fan-in 2, depth O(log n)) can be recognized by a width-5 polynomial-size branching program. As any bounded-width polynomial-size branching program can be simulated by an NC1 circuit, we have that the class of languages recognized by such programs is exactly nonuniform NC1. Further, following Ruzzo (J. Comput. System Sci. 22 (1981), 365–383) and Cook (Inform. and Control 64 (1985) 2–22), if the branching programs are restricted to be ATIME(logn)-uniform, they recognize the same languages as do ATIME(log n)-uniform NC1 circuits, that is, those languages in ATIME(log n). We also extend the method of proof to investigate the complexity of the word problem for a fixed permutation group and show that polynomial size circuits of width 4 also recognize exactly nonuniform NC1

Environmental Impact Determinants: An Empirical Analysis based on the STIRPAT Model

AbstractThis paper attempt to investigate the impact of economic and population growth, urbanization level, energy intensity and Kyoto protocol obligations on carbon dioxide emissions using the STIRPAT model (STochastic Impacts by Regression on Population, Affluence and Technology). Our sample of countries is decomposed into groups according to the revenue level and the analyzed period extends from 1980 through 2010. Using several methods to estimate panel data, we find that there is a significant effect of economic growth, population growth, urbanization level and Kyoto protocol on emissions level and this effect depends on the revenue level

The polypill in the primary prevention of cardiovascular disease: cost-effectiveness in the Dutch population

OBJECTIVES: The aim of the present study was to estimate the cost-effectiveness of the polypill in the primary prevention of cardiovascular disease. DESIGN: A health economic modeling study. SETTING: Primary health care in the Netherlands. PARTICIPANTS: Simulated individuals from the general Dutch population, aged 45-75 years of age. INTERVENTIONS: Opportunistic screening followed by prescription of the polypill to eligible individuals. Eligibility was defined as having a minimum 10-year risk of cardiovascular death as assessed with the SCORE function of alternatively 5%, 7.5%, or 10%. Different versions of the polypill were considered, depending on composition: 1) the Indian polycap, with three different types of blood pressure lowering drugs, a statin, and aspirin; 2) as 1) but without aspirin; 3) as 2) but with a double statin dose. In addition, a scenario of (targeted) separate antihypertensive and/or statin medication was simulated. PRIMARY OUTCOME MEASURES: Cases of acute myocardial infarction or stroke prevented, QALYs gained, and the costs per QALY gained. All interventions were compared with usual care. RESULTS: All scenarios were cost-effective with an incremental cost-effectiveness ratio between €7,900-12,300 per QALY compared with usual care. Most health gains were achieved with the polypill without aspirin and containing a double dose of statins. With a 10-year risk of 7.5% as threshold, this pill would prevent approximately 3.5% of all cardiovascular events. CONCLUSIONS: Opportunistic screening based on global cardiovascular risk assessment followed by polypill prescription to those with increased risk offers a cost-effective strategy. Most health gain is achieved by the polypill without aspirin and a double statin dose

Limited salt consumption reduces the incidence of chronic kidney disease: a modeling study.

In addition to blood pressure and cardiovascular disease, high-salt intake has been associated with renal diseases. The aim of this study is to estimate the potential health impact of salt reduction on chronic kidney disease (CKD) and end-stage kidney disease (ESKD) in the Netherlands

Lifetime cost-effectiveness and equity impacts of the Healthy Primary School of the Future initiative

BACKGROUND: This study estimated the lifetime cost-effectiveness and equity impacts associated with two lifestyle interventions in the Dutch primary school setting (targeting 4-12 year olds). METHODS: The Healthy Primary School of the Future (HPSF; a healthy school lunch and structured physical activity) and the Physical Activity School (PAS; structured physical activity) were compared to the regular Dutch curriculum (N = 1676). An adolescence model, calculating weight development, and the RIVM Chronic Disease Model, calculating overweight-related chronic diseases, were linked to estimate the lifetime impact on chronic diseases, quality adjusted life years (QALYs), healthcare, and productivity costs. Cost-effectiveness was expressed as the additional costs/QALY gained and we used €20,000 as threshold. Scenario analyses accounted for alternative effect maintenance scenarios and equity analyses examined cost-effectiveness in different socioeconomic status (SES) groups. RESULTS: HPSF resulted in a lifetime costs of €773 (societal perspective) and a lifetime QALY gain of 0.039 per child versus control schools. HPSF led to lower costs and more QALYs as compared to PAS. From a societal perspective, HPSF had a cost/QALY gained of €19,734 versus control schools, 50% probability of being cost-effective, and beneficial equity impact (0.02 QALYs gained/child for low versus high SES). The cost-effectiveness threshold was surpassed when intervention effects decayed over time. CONCLUSIONS: HPSF may be a cost-effective and equitable strategy for combatting the lifetime burden of unhealthy lifestyles. The win-win situation will, however, only be realised if the intervention effect is sustained into adulthood for all SES groups. TRIAL REGISTRATION: Clinicaltrials.gov ( NCT02800616 ). Registered 15 June 2016 - Retrospectively registered

Consequences of restricted STI testing for young heterosexuals in the Netherlands on test costs and QALY losses.

Due to rising costs caused by increasing demand for sexually transmitted infection (STI) care, the Dutch government changed the funding of STI clinics. In 2015, a more restrictive testing policy was introduced with syphilis and HIV tests only on indication for younger, heterosexual clients. We evaluated intended savings and missed syphilis and/or HIV infections and explored efficiency of possible test policies

Lifetime cost-effectiveness and equity impacts of the Healthy Primary School of the Future initiative.

BACKGROUND: This study estimated the lifetime cost-effectiveness and equity impacts associated with two lifestyle interventions in the Dutch primary school setting (targeting 4-12 year olds). METHODS: The Healthy Primary School of the Future (HPSF; a healthy school lunch and structured physical activity) and the Physical Activity School (PAS; structured physical activity) were compared to the regular Dutch curriculum (N = 1676). An adolescence model, calculating weight development, and the RIVM Chronic Disease Model, calculating overweight-related chronic diseases, were linked to estimate the lifetime impact on chronic diseases, quality adjusted life years (QALYs), healthcare, and productivity costs. Cost-effectiveness was expressed as the additional costs/QALY gained and we used €20,000 as threshold. Scenario analyses accounted for alternative effect maintenance scenarios and equity analyses examined cost-effectiveness in different socioeconomic status (SES) groups. RESULTS: HPSF resulted in a lifetime costs of €773 (societal perspective) and a lifetime QALY gain of 0.039 per child versus control schools. HPSF led to lower costs and more QALYs as compared to PAS. From a societal perspective, HPSF had a cost/QALY gained of €19,734 versus control schools, 50% probability of being cost-effective, and beneficial equity impact (0.02 QALYs gained/child for low versus high SES). The cost-effectiveness threshold was surpassed when intervention effects decayed over time. CONCLUSIONS: HPSF may be a cost-effective and equitable strategy for combatting the lifetime burden of unhealthy lifestyles. The win-win situation will, however, only be realised if the intervention effect is sustained into adulthood for all SES groups. TRIAL REGISTRATION: Clinicaltrials.gov ( NCT02800616 ). Registered 15 June 2016 - Retrospectively registered

Cost-effectiveness of mandatory bicycle helmet use to prevent traumatic brain injuries and death.

Background Traumatic brain injury (TBI) is the main cause of mortality and severe morbidity in cyclists admitted to Dutch emergency departments (EDs). Although the use of bicycle helmets is an effective way of preventing TBI, this is uncommon in the Netherlands. An option to increase its use is through a legal enforcement. However, little is known about the cost-effectiveness of such mandatory use of helmets in the Dutch context. The current study aimed to assess the cost-effectiveness of a law that enforces helmet use to reduce TBI and TBI-related mortality. Methods The cost-effectiveness was estimated through decision tree modelling. In this study, wearing bicycle helmets enforced by law was compared with the current situation of infrequent voluntary helmet use. The total Dutch cycling population, consisting of 13.5 million people, was included in the model. Model data and parameters were obtained from Statistics Netherlands, the National Road Traffic Database, Dutch Injury Surveillance System, and literature. Effects included were numbers of TBI, death, and disability-adjusted life years (DALY). Costs included were healthcare costs, costs of productivity losses, and helmet costs. Sensitivity analysis was performed to assess which parameter had the largest influence on the incremental cost-effectiveness ratio (ICER). Results The intervention would lead to an estimated reduction of 2942 cases of TBI and 46 deaths. Overall, the incremental costs per 1) death averted, 2) per TBI averted, and 3) per DALY averted were estimated at 1) € 2,002,766, 2) € 31,028 and 3) € 28,465, respectively. Most favorable were the incremental costs per DALY in the 65+ age group: € 17,775. Conclusions The overall costs per DALY averted surpassed the Dutch willingness to pay threshold value of € 20,000 for cost-effectiveness of preventive interventions. However, the cost per DALY averted for the elderly was below this threshold, indicating that in this age group largest effects can be reached. If the price of a helmet would reduce by 20%, which is non-hypothetical in a situation of large-scale purchases and use of these helmets, the introduction of this regulation would result in an intervention that is almost cost-effective in all age groups