Sample records for policy screening models
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Jin, Haomiao; Wu, Shinyi; Di Capua, Paul
2015-09-03
Depression is a common but often undiagnosed comorbid condition of people with diabetes. Mass screening can detect undiagnosed depression but may require significant resources and time. The objectives of this study were 1) to develop a clinical forecasting model that predicts comorbid depression among patients with diabetes and 2) to evaluate a model-based screening policy that saves resources and time by screening only patients considered as depressed by the clinical forecasting model. We trained and validated 4 machine learning models by using data from 2 safety-net clinical trials; we chose the one with the best overall predictive ability as the ultimate model. We compared model-based policy with alternative policies, including mass screening and partial screening, on the basis of depression history or diabetes severity. Logistic regression had the best overall predictive ability of the 4 models evaluated and was chosen as the ultimate forecasting model. Compared with mass screening, the model-based policy can save approximately 50% to 60% of provider resources and time but will miss identifying about 30% of patients with depression. Partial-screening policy based on depression history alone found only a low rate of depression. Two other heuristic-based partial screening policies identified depression at rates similar to those of the model-based policy but cost more in resources and time. The depression prediction model developed in this study has compelling predictive ability. By adopting the model-based depression screening policy, health care providers can use their resources and time better and increase their efficiency in managing their patients with depression.
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Cost-effectiveness of breast cancer screening policies using simulation.
Gocgun, Y; Banjevic, D; Taghipour, S; Montgomery, N; Harvey, B J; Jardine, A K S; Miller, A B
2015-08-01
In this paper, we study breast cancer screening policies using computer simulation. We developed a multi-state Markov model for breast cancer progression, considering both the screening and treatment stages of breast cancer. The parameters of our model were estimated through data from the Canadian National Breast Cancer Screening Study as well as data in the relevant literature. Using computer simulation, we evaluated various screening policies to study the impact of mammography screening for age-based subpopulations in Canada. We also performed sensitivity analysis to examine the impact of certain parameters on number of deaths and total costs. The analysis comparing screening policies reveals that a policy in which women belonging to the 40-49 age group are not screened, whereas those belonging to the 50-59 and 60-69 age groups are screened once every 5 years, outperforms others with respect to cost per life saved. Our analysis also indicates that increasing the screening frequencies for the 50-59 and 60-69 age groups decrease mortality, and that the average number of deaths generally decreases with an increase in screening frequency. We found that screening annually for all age groups is associated with the highest costs per life saved. Our analysis thus reveals that cost per life saved increases with an increase in screening frequency. Copyright © 2015 Elsevier Ltd. All rights reserved.
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Assessing Screening Policies for Childhood Obesity
Wein, Lawrence M.; Yang, Yan; Goldhaber-Fiebert, Jeremy D.
2014-01-01
To address growing concerns over childhood obesity, the United States Preventive Services Task Force (USPSTF) recently recommended that children undergo obesity screening beginning at age 6 [1]. An Expert Committee recommends starting at age 2 [2]. Analysis is needed to assess these recommendations and investigate whether there are better alternatives. We model the age- and sex-specific population-wide distribution of body mass index (BMI) through age 18 using National Longitudinal Survey of Youth data [3]. The impact of treatment on BMI is estimated using the targeted systematic review performed to aid the USPSTF [4]. The prevalence of hypertension and diabetes at age 40 are estimated from the Panel Study of Income Dynamics [5]. We fix the screening interval at 2 years, and derive the age- and sex-dependent BMI thresholds that minimize adult disease prevalence, subject to referring a specified percentage of children for treatment yearly. We compare this optimal biennial policy to biennial versions of the USPSTF and Expert Committee recommendations. Compared to the USPSTF recommendation, the optimal policy reduces adult disease prevalence by 3% in relative terms (the absolute reductions are disease prevalence at a 28% reduction in treatment referral rate. If compared to the Expert Committee recommendation, the reductions change to 6% and 40%, respectively. The optimal policy treats mostly 16 year olds and few children under age 14. Our results suggest that adult disease is minimized by focusing childhood obesity screening and treatment on older adolescents. PMID:22240724
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Jin, Haomiao; Wu, Shinyi; Di Capua, Paul
2015-01-01
Introduction Depression is a common but often undiagnosed comorbid condition of people with diabetes. Mass screening can detect undiagnosed depression but may require significant resources and time. The objectives of this study were 1) to develop a clinical forecasting model that predicts comorbid depression among patients with diabetes and 2) to evaluate a model-based screening policy that saves resources and time by screening only patients considered as depressed by the clinical forecasting...
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Analyzing Screening Policies for Childhood Obesity
Yang, Yan; Goldhaber-Fiebert, Jeremy D.; Wein, Lawrence M.
2013-01-01
Due to the health and economic costs of childhood obesity, coupled with studies suggesting the benefits of comprehensive (dietary, physical activity and behavioral counseling) intervention, the United States Preventive Services Task Force recently recommended childhood screening and intervention for obesity beginning at age six. Using a longitudinal data set consisting of the body mass index of 3164 children up to age 18 and another longitudinal data set containing the body mass index at ages 18 and 40 and the presence or absence of disease (hypertension and diabetes) at age 40 for 747 people, we formulate and numerically solve – separately for boys and girls – a dynamic programming problem for the optimal biennial (i.e., at ages 2, 4, …, 16) obesity screening thresholds. Unlike most screening problem formulations, we take a societal viewpoint, where the state of the system at each age is the population-wide probability density function of the body mass index. Compared to the biennial version of the task force’s recommendation, the screening thresholds derived from the dynamic program achieve a relative reduction in disease prevalence of 3% at the same screening (and treatment) cost, or – due to the flatness of the disease vs. screening tradeoff curve – achieves the same disease prevalence at a 28% relative reduction in cost. Compared to the task force’s policy, which uses the 95th percentile of body mass index (from cross-sectional growth charts tabulated by the Centers for Disease Control and Prevention) as the screening threshold for each age, the dynamic programming policy treats mostly 16 year olds (including many who are not obese) and very few males under 14 years old. While our results suggest that adult hypertension and diabetes are minimized by focusing childhood obesity screening and treatment on older adolescents, the shortcomings in the available data and the narrowness of the medical outcomes considered prevent us from making a
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Cervical cancer screening policies and coverage in Europe
DEFF Research Database (Denmark)
Anttila, Ahti; von Karsa, Lawrence; Aasmaa, Auni
2009-01-01
with education, training and communication among women, medical professionals and authorities are required, accordingly. The study indicates that, despite substantial efforts, the recommendations of the Council of the EU on organised population-based screening for cervical cancer are not yet fulfilled. Decision......The aim of the study was to compare current policy, organisation and coverage of cervical cancer screening programmes in the European Union (EU) member states with European and other international recommendations. According to the questionnaire-based survey, there are large variations in cervical...... cancer screening policies and inadequacies in the key organisational elements of the programme such as registration and monitoring required for quality-assurance and fail-safe mechanisms. Based on data from available screening registers, coverage of the screening test taken within the population...
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Directory of Open Access Journals (Sweden)
Nikolai Mühlberger
2017-06-01
Full Text Available Abstract Background A recent recalibration of the ONCOTYROL Prostate Cancer Outcome and Policy (PCOP Model, assuming that latent prostate cancer (PCa detectable at autopsy might be detectable by screening as well, resulted in considerable worsening of the benefit-harm balance of screening. In this study, we used the recalibrated model to assess the effects of familial risk, quality of life (QoL preferences, age, and active surveillance. Methods Men with average and elevated familial PCa risk were simulated in separate models, differing in familial risk parameters. Familial risk was assumed to affect PCa onset and progression simultaneously in the base-case, and separately in scenario analyses. Evaluated screening strategies included one-time screening at different ages, and screening at different intervals and age ranges. Optimal screening strategies were identified depending on age and individual QoL preferences. Strategies were additionally evaluated with active surveillance by biennial re-biopsy delaying treatment of localized cancer until grade progression to Gleason score ≥ 7. Results Screening men with average PCa risk reduced quality-adjusted life expectancy (QALE even under favorable assumptions. Men with elevated familial risk, depending on age and disutilities, gained QALE. While for men with familial risk aged 55 and 60 years annual screening to age 69 was the optimal strategy over most disutility ranges, no screening was the preferred option for 65 year-old men with average and above disutilities. Active surveillance greatly reduced overtreatment, but QALE gains by averted adverse events were opposed by losses due to delayed treatment and additional biopsies. The effect of active surveillance on the benefit-harm balance of screening differed between populations, as net losses and gains in QALE predicted for screening without active surveillance in men with average and familial PCa risk, respectively, were both reduced
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Systematic review of model-based cervical screening evaluations.
Mendes, Diana; Bains, Iren; Vanni, Tazio; Jit, Mark
2015-05-01
Optimising population-based cervical screening policies is becoming more complex due to the expanding range of screening technologies available and the interplay with vaccine-induced changes in epidemiology. Mathematical models are increasingly being applied to assess the impact of cervical cancer screening strategies. We systematically reviewed MEDLINE®, Embase, Web of Science®, EconLit, Health Economic Evaluation Database, and The Cochrane Library databases in order to identify the mathematical models of human papillomavirus (HPV) infection and cervical cancer progression used to assess the effectiveness and/or cost-effectiveness of cervical cancer screening strategies. Key model features and conclusions relevant to decision-making were extracted. We found 153 articles meeting our eligibility criteria published up to May 2013. Most studies (72/153) evaluated the introduction of a new screening technology, with particular focus on the comparison of HPV DNA testing and cytology (n = 58). Twenty-eight in forty of these analyses supported HPV DNA primary screening implementation. A few studies analysed more recent technologies - rapid HPV DNA testing (n = 3), HPV DNA self-sampling (n = 4), and genotyping (n = 1) - and were also supportive of their introduction. However, no study was found on emerging molecular markers and their potential utility in future screening programmes. Most evaluations (113/153) were based on models simulating aggregate groups of women at risk of cervical cancer over time without accounting for HPV infection transmission. Calibration to country-specific outcome data is becoming more common, but has not yet become standard practice. Models of cervical screening are increasingly used, and allow extrapolation of trial data to project the population-level health and economic impact of different screening policy. However, post-vaccination analyses have rarely incorporated transmission dynamics. Model calibration to country
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Melanoma screening: Informing public health policy with quantitative modelling.
Directory of Open Access Journals (Sweden)
Stephen Gilmore
1982 has resulted in greater diagnostic incidence and reduced mortality, but the reduced mortality carried a significant cost per life saved. I implement the model out to 2028 and demonstrate that the enhanced secondary prevention that began in 1982 becomes increasingly cost-effective over the period 2013-2028. On the other hand, I show that reductions in mortality achieved by significantly enhancing secondary prevention beyond 2013 levels are comparable with those achieved by only modest improvements in late-stage disease survival. Given the ballooning costs of increased melanoma surveillance, I suggest the process of public health policy decision-making-particularly with respect to the public funding of melanoma screening and discretionary mole removal-would be better served by incorporating the results of quantitative modelling.
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Directory of Open Access Journals (Sweden)
Elizabeth S. Burnside MD, MPH, MS
2017-07-01
Full Text Available Background: There are no publicly available tools designed specifically to assist policy makers to make informed decisions about the optimal ages of breast cancer screening initiation for different populations of US women. Objective: To use three established simulation models to develop a web-based tool called Mammo OUTPuT. Methods: The simulation models use the 1970 US birth cohort and common parameters for incidence, digital screening performance, and treatment effects. Outcomes include breast cancers diagnosed, breast cancer deaths averted, breast cancer mortality reduction, false-positive mammograms, benign biopsies, and overdiagnosis. The Mammo OUTPuT tool displays these outcomes for combinations of age at screening initiation (every year from 40 to 49, annual versus biennial interval, lifetime versus 10-year horizon, and breast density, compared to waiting to start biennial screening at age 50 and continuing to 74. The tool was piloted by decision makers (n = 16 who completed surveys. Results: The tool demonstrates that benefits in the 40s increase linearly with earlier initiation age, without a specific threshold age. Likewise, the harms of screening increase monotonically with earlier ages of initiation in the 40s. The tool also shows users how the balance of benefits and harms varies with breast density. Surveys revealed that 100% of users (16/16 liked the appearance of the site; 94% (15/16 found the tool helpful; and 94% (15/16 would recommend the tool to a colleague. Conclusions: This tool synthesizes a representative subset of the most current CISNET (Cancer Intervention and Surveillance Modeling Network simulation model outcomes to provide policy makers with quantitative data on the benefits and harms of screening women in the 40s. Ultimate decisions will depend on program goals, the population served, and informed judgments about the weight of benefits and harms.
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Breast screening policy: Are we heading in the right direction?
International Nuclear Information System (INIS)
Evans, A.; Whelehan, P.
2011-01-01
There is a large body of evidence supporting 2-yearly screening of women aged 50-69 years. There is good evidence for a mortality reduction from mammographic screening in women aged 40 to 49 years but a 1-year interval is required. The lack of specificity of screening in young women does remain a problem. There is no evidence to suggest that a single screen between the ages of 47 and 50 years within a programme screening at 3-year intervals will reduce mortality; the trials showing a mortality benefit in women in their 40s included multiple screening episodes and shorter screening intervals. There is no randomized, controlled trial evidence to support screening in women aged above 70 years and screening this age group will cause greater harm than in younger women through higher rates of over-diagnosis and consequent over-treatment. The randomized phase of the screening age extension, which at the moment is planned to last only 6 years, should not be immediately followed by general implementation of the policy. Only if and when additional mortality reductions and an acceptable balance between benefit and harms are shown to be achieved by the extra screens should the 2007 Cancer Reform Strategy policy on age extension be implemented. Resources saved by delaying or abandoning the roll-out of the age extension could potentially be redirected towards reducing the current 3 year screening interval to 2 years in women aged 50-69 years. However, reducing the screening interval to 2 years for women aged 50-69 years would require significantly more screening invitations and resources than the proposed age extension.
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Breast screening policy: Are we heading in the right direction?
Energy Technology Data Exchange (ETDEWEB)
Evans, A., E-mail: a.z.evans@dundee.ac.uk [Dundee Cancer Centre, Ninewells Hospital and Medical School, University of Dundee, Dundee (United Kingdom); Whelehan, P. [Dundee Cancer Centre, Ninewells Hospital and Medical School, University of Dundee, Dundee (United Kingdom)
2011-10-15
There is a large body of evidence supporting 2-yearly screening of women aged 50-69 years. There is good evidence for a mortality reduction from mammographic screening in women aged 40 to 49 years but a 1-year interval is required. The lack of specificity of screening in young women does remain a problem. There is no evidence to suggest that a single screen between the ages of 47 and 50 years within a programme screening at 3-year intervals will reduce mortality; the trials showing a mortality benefit in women in their 40s included multiple screening episodes and shorter screening intervals. There is no randomized, controlled trial evidence to support screening in women aged above 70 years and screening this age group will cause greater harm than in younger women through higher rates of over-diagnosis and consequent over-treatment. The randomized phase of the screening age extension, which at the moment is planned to last only 6 years, should not be immediately followed by general implementation of the policy. Only if and when additional mortality reductions and an acceptable balance between benefit and harms are shown to be achieved by the extra screens should the 2007 Cancer Reform Strategy policy on age extension be implemented. Resources saved by delaying or abandoning the roll-out of the age extension could potentially be redirected towards reducing the current 3 year screening interval to 2 years in women aged 50-69 years. However, reducing the screening interval to 2 years for women aged 50-69 years would require significantly more screening invitations and resources than the proposed age extension.
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Newborn bloodspot screening policy framework for Australia
Directory of Open Access Journals (Sweden)
Peter O'Leary
2015-09-01
Full Text Available Background The aim of newborn bloodspot screening (NBS is to identify rare genetic and non-genetic conditions in children soon after birth in order to commence therapies that prevent the development of progressive, serious, and irreversible disabilities. Universal NBS programmes have been implemented in most countries, with minor adaptations to target conditions most relevant to the local healthcare environment. Aims In this article, we describe the initiatives of international and Australian governments to develop policies to address the expansion of NBS in their healthcare systems. Methods We have reviewed published public policies and literature to formulate recommendations based on clinical, social, legal, and ethical principles to inform a national governance and policy framework for Australia. Results Australian policy makers have been slow to develop a coordinated plan. While the experience from other governments can guide our national policy, there are specific areas that require further consideration by Australian health experts. Key reforms involve the separation of policy and operational activities, multidisciplinary decision-making and oversight by the Australian Health Ministers’ Advisory Council for policy direction. Conclusion A formal national policy framework will guide the coordination of NBS services that can adapt to the needs of Australian children and families.
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Policy Forum Improving the screening and treatment of hypertension ...
African Journals Online (AJOL)
2008-12-27
Dec 27, 2008 ... advantages and disadvantages associated with screening and referral. Policy Option 3: ... Skill-building approaches such as training with healthcare workers or .... Science and Technology, Grand Challenges Canada and.
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Screening for a Chronic Disease: A Multiple Stage Duration Model with Partial Observability.
Mroz, Thomas A; Picone, Gabriel; Sloan, Frank; Yashkin, Arseniy P
2016-08-01
We estimate a dynamic multi-stage duration model to investigate how early detection of diabetes can delay the onset of lower extremity complications and death. We allow for partial observability of the disease stage, unmeasured heterogeneity, and endogenous timing of diabetes screening. Timely diagnosis appears important. We evaluate the effectiveness of two potential policies to reduce the monetary costs of frequent screening in terms of lost longevity. Compared to the status quo, the more restrictive policy yields an implicit value for an additional year of life of about $50,000, while the less restrictive policy implies a value of about $120,000.
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Withdrawing low risk women from cervical screening programmes: mathematical modelling study.
Sherlaw-Johnson, C; Gallivan, S; Jenkins, D
1999-02-06
To evaluate the impact of policies for removing women before the recommended age of 64 from screening programmes for cervical cancer in the United Kingdom. A mathematical model of the clinical course of precancerous lesions which accounts for the influence of infection with the human papillomavirus, the effects of screening on the progression of disease, and the accuracy of the testing procedures. Two policies are compared: one in which women are withdrawn from the programme if their current smear is negative and they have a recent history of regular, negative results and one in which women are withdrawn if their current smear test is negative and a simultaneous test is negative for exposure to high risk types of human papillomavirus. United Kingdom cervical screening programme. The incidence of invasive cervical cancer and the use of resources. Early withdrawal of selected women from the programme is predicted to give rise to resource savings of up to 25% for smear tests and 18% for colposcopies when withdrawal occurs from age 50, the youngest age considered in the study. An increase in the incidence of invasive cervical cancer, by up to 2 cases/100 000 women each year is predicted. Testing for human papillomavirus infection to determine which women should be withdrawn from the programme makes little difference to outcome. This model systematically analyses the consequences of screening options using available data and the clinical course of precancerous lesions. If further audit studies confirm the model's forecasts, a policy of early withdrawal might be considered. This would be likely to release substantial resources which could be channelled into other aspects of health care or may be more effectively used within the cervical screening programme to counteract the possible increase in cancer incidence that early withdrawal might bring.
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DEFF Research Database (Denmark)
Siren, Anu Kristiina; Haustein, Sonja
2015-01-01
Chronological age, per se, seems to be, in the case of mature drivers, only a weak predictor of safe driving performance. However, screening policies based on chronological age are widely used. Nevertheless, lately, more evidence-based policies have been called for. In this paper we first......, investigate the evidence for and against having an age-based driver screening policy in place; second, we map and compare the current driving licensing policies in European Union (EU) member states in order to examine the variation; and third, we draw conclusions based on the literature and the policy mapping...... are likely to limit the mobility and potentially worsen the safety of older persons....
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Grosse, Scott D; Thompson, John D; Ding, Yao; Glass, Michael
2016-06-01
Newborn screening not only saves lives but can also yield net societal economic benefit, in addition to benefits such as improved quality of life to affected individuals and families. Calculations of net economic benefit from newborn screening include the monetary equivalent of avoided deaths and reductions in costs of care for complications associated with late-diagnosed individuals minus the additional costs of screening, diagnosis, and treatment associated with prompt diagnosis. Since 2001 the Washington State Department of Health has successfully implemented an approach to conducting evidence-based economic evaluations of disorders proposed for addition to the state-mandated newborn screening panel. Economic evaluations can inform policy decisions on the expansion of newborn screening panels. This article documents the use of cost-benefit models in Washington State as part of the rule-making process that resulted in the implementation of screening for medium-chain acyl-CoA dehydrogenase (MCAD) deficiency and 4 other metabolic disorders in 2004, cystic fibrosis (CF) in 2006, 15 other metabolic disorders in 2008, and severe combined immune deficiency (SCID) in 2014. We reviewed Washington State Department of Health internal reports and spreadsheet models of expected net societal benefit of adding disorders to the state newborn screening panel. We summarize the assumptions and findings for 2 models (MCAD and CF) and discuss them in relation to findings in the peer-reviewed literature. The MCAD model projected a benefit-cost ratio of 3.4 to 1 based on assumptions of a 20.0 percentage point reduction in infant mortality and a 13.9 percentage point reduction in serious developmental disability. The CF model projected a benefit-cost ratio of 4.0-5.4 to 1 for a discount rate of 3%-4% and a plausible range of 1-2 percentage point reductions in deaths up to age 10 years. The Washington State cost-benefit models of newborn screening were broadly consistent with peer
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Shedrawy, J; Siroka, A; Oxlade, O; Matteelli, A; Lönnroth, K
2017-09-01
Tuberculosis (TB) in migrants from endemic to low-incidence countries results mainly from the reactivation of latent tuberculous infection (LTBI). LTBI screening policies for migrants vary greatly between countries, and the evidence on the cost-effectiveness of the different approaches is weak and heterogeneous. The aim of this review was to assess the methodology used in published economic evaluations of LTBI screening among migrants to identify critical methodological options that must be considered when using modelling to determine value for money from different economic perspectives. Three electronic databases were searched and 10 articles were included. There was considerable variation across this small number of studies with regard to economic perspective, main outcomes, modelling technique, screening options and target populations considered, as well as in parameterisation of the epidemiological situation, test accuracy, efficacy, safety and programme performance. Only one study adopted a societal perspective; others adopted a health care or wider government perspective. Parameters representing the cascade of screening and treating LTBI varied widely, with some studies using highly aspirational scenarios. This review emphasises the need for a more harmonised approach for economic analysis, and better transparency in how policy options and economic perspectives influence methodological choices. Variability is justifiable for some parameters. However, sufficient data are available to standardise others. A societal perspective is ideal, but can be challenging due to limited data. Assumptions about programme performance should be based on empirical data or at least realistic assumptions. Results should be interpreted within specific contexts and policy options, with cautious generalisations.
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[Economic impact of lung cancer screening in France: A modeling study].
Gendarme, S; Perrot, É; Reskot, F; Bhoowabul, V; Fourre, G; Souquet, P-J; Milleron, B; Couraud, S
2017-09-01
The National Lung Screening Trial found that, in a selected population with a high risk of lung cancer, an annual low-dose CT-scan decreased lung cancer mortality by 20% and overall mortality by 7% compared to annual chest X-Ray. In France, a work group stated that individual screening should be considered in this setting. However, the economic impact of an organized and generalized (to all eligible individuals) screening in France was never reported. This is a modeling study using French population demographic data and published data from randomized screening trials. We used the same selection criteria as NLST: 55-74-year-old smokers for at least 30 pack-years, current smoker or quit less than 15 years. We computed a second model including also 50-54-year-old individuals. Then, we used different participation rates: 65%, 45%, and 32%. According to the considered model, there would be 1,650,588 to 2,283,993 subjects eligible to screening in France. According to the model and participation rate, lung cancer screening would diagnose 3600 to 10,118 stages 1/2 lung cancer each year. There would be 5991 to 16,839 false-positives, of whom 1416 to 3981 would undergo unnecessary surgery. Screening policy would cost 105 to 215 € million per year. However, increasing the price of a cigarette pack by 0.05 to 0.10 € would fully cover the screening costs. Participation rate is a key point for screening impact. Screening could be easily funded by a small increase in cigarette prices. Copyright © 2015 SPLF. Published by Elsevier Masson SAS. All rights reserved.
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International Nuclear Information System (INIS)
Martin, W.E.; McDonald, L.A.
1997-01-01
The eight book chapters demonstrate the link between the physical models of the environment and the policy analysis in support of policy making. Each chapter addresses an environmental policy issue using a quantitative modeling approach. The volume addresses three general areas of environmental policy - non-point source pollution in the agricultural sector, pollution generated in the extractive industries, and transboundary pollutants from burning fossil fuels. The book concludes by discussing the modeling efforts and the use of mathematical models in general. Chapters are entitled: modeling environmental policy: an introduction; modeling nonpoint source pollution in an integrated system (agri-ecological); modeling environmental and trade policy linkages: the case of EU and US agriculture; modeling ecosystem constraints in the Clean Water Act: a case study in Clearwater National Forest (subject to discharge from metal mining waste); costs and benefits of coke oven emission controls; modeling equilibria and risk under global environmental constraints (discussing energy and environmental interrelations); relative contribution of the enhanced greenhouse effect on the coastal changes in Louisiana; and the use of mathematical models in policy evaluations: comments. The paper on coke area emission controls has been abstracted separately for the IEA Coal Research CD-ROM
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Abouk, Rahi; Grosse, Scott D; Ailes, Elizabeth C; Oster, Matthew E
2017-12-05
In 2011, critical congenital heart disease was added to the US Recommended Uniform Screening Panel for newborns, but whether state implementation of screening policies has been associated with infant death rates is unknown. To assess whether there was an association between implementation of state newborn screening policies for critical congenital heart disease and infant death rates. Observational study with group-level analyses. A difference-in-differences analysis was conducted using the National Center for Health Statistics' period linked birth/infant death data set files for 2007-2013 for 26 546 503 US births through June 30, 2013, aggregated by month and state of birth. State policies were classified as mandatory or nonmandatory (including voluntary policies and mandates that were not yet implemented). As of June 1, 2013, 8 states had implemented mandatory screening policies, 5 states had voluntary screening policies, and 9 states had adopted but not yet implemented mandates. Numbers of early infant deaths (between 24 hours and 6 months of age) coded for critical congenital heart disease or other/unspecified congenital cardiac causes for each state-month birth cohort. Between 2007 and 2013, there were 2734 deaths due to critical congenital heart disease and 3967 deaths due to other/unspecified causes. Critical congenital heart disease death rates in states with mandatory screening policies were 8.0 (95% CI, 5.4-10.6) per 100 000 births (n = 37) in 2007 and 6.4 (95% CI, 2.9-9.9) per 100 000 births (n = 13) in 2013 (for births by the end of July); for other/unspecified cardiac causes, death rates were 11.7 (95% CI, 8.6-14.8) per 100 000 births in 2007 (n = 54) and 10.3 (95% CI, 5.9-14.8) per 100 000 births (n = 21) in 2013. Early infant deaths from critical congenital heart disease through December 31, 2013, decreased by 33.4% (95% CI, 10.6%-50.3%), with an absolute decline of 3.9 (95% CI, 3.6-4.1) deaths per 100 000 births after
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Jones, Edmund; Masconi, Katya L.; Sweeting, Michael J.; Thompson, Simon G.; Powell, Janet T.
2018-01-01
Markov models are often used to evaluate the cost-effectiveness of new healthcare interventions but they are sometimes not flexible enough to allow accurate modeling or investigation of alternative scenarios and policies. A Markov model previously demonstrated that a one-off invitation to screening for abdominal aortic aneurysm (AAA) for men aged 65 y in the UK and subsequent follow-up of identified AAAs was likely to be highly cost-effective at thresholds commonly adopted in the UK (£20,000 to £30,000 per quality adjusted life-year). However, new evidence has emerged and the decision problem has evolved to include exploration of the circumstances under which AAA screening may be cost-effective, which the Markov model is not easily able to address. A new model to handle this more complex decision problem was needed, and the case of AAA screening thus provides an illustration of the relative merits of Markov models and discrete event simulation (DES) models. An individual-level DES model was built using the R programming language to reflect possible events and pathways of individuals invited to screening v. those not invited. The model was validated against key events and cost-effectiveness, as observed in a large, randomized trial. Different screening protocol scenarios were investigated to demonstrate the flexibility of the DES. The case of AAA screening highlights the benefits of DES, particularly in the context of screening studies.
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Directory of Open Access Journals (Sweden)
Nicholas X Tan
Full Text Available Syphilis is a major public health problem in many regions of China, with increases in congenital syphilis (CS cases causing concern. The Chinese Ministry of Health recently announced a comprehensive 10-y national syphilis control plan focusing on averting CS. The decision analytic model presented here quantifies the impact of the planned strategies to determine whether they are likely to meet the goals laid out in the control plan.Our model incorporated data on age-stratified fertility, female adult syphilis cases, and empirical syphilis transmission rates to estimate the number of CS cases associated with prenatal syphilis infection on a yearly basis. Guangdong Province was the focus of this analysis because of the availability of high-quality demographic and public health data. Each model outcome was simulated 1,000 times to incorporate uncertainty in model inputs. The model was validated using data from a CS intervention program among 477,656 women in China. Sensitivity analyses were performed to identify which variables are likely to be most influential in achieving Chinese and international policy goals. Increasing prenatal screening coverage was the single most effective strategy for reducing CS cases. An incremental increase in prenatal screening from the base case of 57% coverage to 95% coverage was associated with 106 (95% CI: 101, 111 CS cases averted per 100,000 live births (58% decrease. The policy strategies laid out in the national plan led to an outcome that fell short of the target, while a four-pronged comprehensive syphilis control strategy consisting of increased prenatal screening coverage, increased treatment completion, earlier prenatal screening, and improved syphilis test characteristics was associated with 157 (95% CI: 154, 160 CS cases averted per 100,000 live births (85% decrease.The Chinese national plan provides a strong foundation for syphilis control, but more comprehensive measures that include earlier and more
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Tan, Nicholas X.; Rydzak, Chara; Yang, Li-Gang; Vickerman, Peter; Yang, Bin; Peeling, Rosanna W.; Hawkes, Sarah; Chen, Xiang-Sheng; Tucker, Joseph D.
2013-01-01
Background Syphilis is a major public health problem in many regions of China, with increases in congenital syphilis (CS) cases causing concern. The Chinese Ministry of Health recently announced a comprehensive 10-y national syphilis control plan focusing on averting CS. The decision analytic model presented here quantifies the impact of the planned strategies to determine whether they are likely to meet the goals laid out in the control plan. Methods and Findings Our model incorporated data on age-stratified fertility, female adult syphilis cases, and empirical syphilis transmission rates to estimate the number of CS cases associated with prenatal syphilis infection on a yearly basis. Guangdong Province was the focus of this analysis because of the availability of high-quality demographic and public health data. Each model outcome was simulated 1,000 times to incorporate uncertainty in model inputs. The model was validated using data from a CS intervention program among 477,656 women in China. Sensitivity analyses were performed to identify which variables are likely to be most influential in achieving Chinese and international policy goals. Increasing prenatal screening coverage was the single most effective strategy for reducing CS cases. An incremental increase in prenatal screening from the base case of 57% coverage to 95% coverage was associated with 106 (95% CI: 101, 111) CS cases averted per 100,000 live births (58% decrease). The policy strategies laid out in the national plan led to an outcome that fell short of the target, while a four-pronged comprehensive syphilis control strategy consisting of increased prenatal screening coverage, increased treatment completion, earlier prenatal screening, and improved syphilis test characteristics was associated with 157 (95% CI: 154, 160) CS cases averted per 100,000 live births (85% decrease). Conclusions The Chinese national plan provides a strong foundation for syphilis control, but more comprehensive measures
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Rutter, Carolyn M; Knudsen, Amy B; Marsh, Tracey L; Doria-Rose, V Paul; Johnson, Eric; Pabiniak, Chester; Kuntz, Karen M; van Ballegooijen, Marjolein; Zauber, Ann G; Lansdorp-Vogelaar, Iris
2016-07-01
Microsimulation models synthesize evidence about disease processes and interventions, providing a method for predicting long-term benefits and harms of prevention, screening, and treatment strategies. Because models often require assumptions about unobservable processes, assessing a model's predictive accuracy is important. We validated 3 colorectal cancer (CRC) microsimulation models against outcomes from the United Kingdom Flexible Sigmoidoscopy Screening (UKFSS) Trial, a randomized controlled trial that examined the effectiveness of one-time flexible sigmoidoscopy screening to reduce CRC mortality. The models incorporate different assumptions about the time from adenoma initiation to development of preclinical and symptomatic CRC. Analyses compare model predictions to study estimates across a range of outcomes to provide insight into the accuracy of model assumptions. All 3 models accurately predicted the relative reduction in CRC mortality 10 years after screening (predicted hazard ratios, with 95% percentile intervals: 0.56 [0.44, 0.71], 0.63 [0.51, 0.75], 0.68 [0.53, 0.83]; estimated with 95% confidence interval: 0.56 [0.45, 0.69]). Two models with longer average preclinical duration accurately predicted the relative reduction in 10-year CRC incidence. Two models with longer mean sojourn time accurately predicted the number of screen-detected cancers. All 3 models predicted too many proximal adenomas among patients referred to colonoscopy. Model accuracy can only be established through external validation. Analyses such as these are therefore essential for any decision model. Results supported the assumptions that the average time from adenoma initiation to development of preclinical cancer is long (up to 25 years), and mean sojourn time is close to 4 years, suggesting the window for early detection and intervention by screening is relatively long. Variation in dwell time remains uncertain and could have important clinical and policy implications. © The
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Barry, Gerard P; Tauber, Kate; Emmanuel, Gregory; Horgan, Michael J; Simon, John W
2013-06-01
To determine the effectiveness of a series of policy changes designed to increase the attendance rate for outpatient retinopathy of prematurity (ROP) screening examinations. We retrospectively reviewed the records of consecutive neonatal intensive care unit patients before and after the implementation of policy changes. Policy changes included parent education forms, streamlined scheduling, and creation of a log for all patients seen. The primary outcome measure was attendance rates for the first outpatient appointment after discharge. The Fisher exact test was used to compare rates between the two groups. Before the policy was implemented, 22 of 52 (42%) neonates and their caregivers attended their first outpatient ROP screening examination on the recommended date. This rate improved significantly after policy implementation, when 46 of 57 (81%) neonates and their caregivers were seen on the recommended date (P attendance rates for initial outpatient ROP examinations and the number of patients who ultimately met criteria for conclusion of acute retinal screening examinations significantly improved after the implementation of new policies. Copyright © 2013 American Association for Pediatric Ophthalmology and Strabismus. Published by Mosby, Inc. All rights reserved.
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Directory of Open Access Journals (Sweden)
Wyatt Lawrence A
2005-11-01
Full Text Available Abstract Background Screening for adolescent idiopathic scoliosis (AIS is a commonly performed procedure for school children during the high risk years. The PRECEDE-PROCEDE (PP model is a health promotion planning model that has not been utilized for the clinical diagnosis of AIS. The purpose of this research is to study AIS in the school age population using the PP model and its relevance for community, school, and clinical health promotion. Methods MEDLINE was utilized to locate AIS data. Studies were screened for relevance and applicability under the auspices of the PP model. Where data was unavailable, expert opinion was utilized based on consensus. Results The social assessment of quality of life is limited with few studies approaching the long-term effects of AIS. Epidemiologically, AIS is the most common form of scoliosis and leading orthopedic problem in children. Behavioral/environmental studies focus on discovering etiologic relationships yet this data is confounded because AIS is not a behavioral. Illness and parenting health behaviors can be appreciated. The educational diagnosis is confounded because AIS is an orthopedic disorder and not behavioral. The administration/policy diagnosis is hindered in that scoliosis screening programs are not considered cost-effective. Policies are determined in some schools because 26 states mandate school scoliosis screening. There exists potential error with the Adam's test. The most widely used measure in the PP model, the Health Belief Model, has not been utilized in any AIS research. Conclusion The PP model is a useful tool for a comprehensive study of a particular health concern. This research showed where gaps in AIS research exist suggesting that there may be problems to the implementation of school screening. Until research disparities are filled, implementation of AIS screening by school, community, and clinical health promotion will be compromised. Lack of data and perceived importance by
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Advantages of type and screen policy: Perspective from a developing country!
Aggarwal, Geet; Tiwari, Aseem K; Arora, Dinesh; Dara, Ravi C; Acharya, Devi P; Bhardwaj, Gunjan; Sharma, Jyoti
2018-01-01
The authors' center recently changed their pretransfusion testing protocol from "conventional" type and screen (TS) with anti-human globulin (AHG) crossmatch (Policy A) to TS with immediate-spin (IS) crossmatch (Policy B). Red blood cell (RBC) units were issued after compatible IS crossmatch as and when required instead of AHG crossmatch. This study was conducted to compare the effects of change of policy from A to B over 1-year period on crossmatch-to-transfusion (C/T) ratio, RBC issue turnaround time (TAT), outdating of RBC, man-hours consumption, and monetary savings. This was a comparative, prospective study conducted by the Department of Transfusion Medicine of a tertiary hospital-based blood bank in Northern India. The Policy B was implemented in the department from January 2014. Relevant retrospective data for comparison of the previous 1 year, when Policy A was practiced, were derived from hospital information system. 23909 and 24724 RBC units transfused to patients admitted to the hospital during respective 1-year period of practice for Policy A and B. There was significant reduction in C/T ratio (1.94 vs. 1.01) and RBC issue TAT (79 vs. 65 min) with Policy B. Expiry due to outdating reduced (37 vs. zero) along with man-hours (16% reduction) and monetary (33% reduction) savings. Use of 'TS with IS crossmatch' policy provides multiple advantages to all the stakeholders; blood banker, clinician, patient, and the hospital management.
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Screening for Prediabetes Using Machine Learning Models
Directory of Open Access Journals (Sweden)
Soo Beom Choi
2014-01-01
Full Text Available The global prevalence of diabetes is rapidly increasing. Studies support the necessity of screening and interventions for prediabetes, which could result in serious complications and diabetes. This study aimed at developing an intelligence-based screening model for prediabetes. Data from the Korean National Health and Nutrition Examination Survey (KNHANES were used, excluding subjects with diabetes. The KNHANES 2010 data (n=4685 were used for training and internal validation, while data from KNHANES 2011 (n=4566 were used for external validation. We developed two models to screen for prediabetes using an artificial neural network (ANN and support vector machine (SVM and performed a systematic evaluation of the models using internal and external validation. We compared the performance of our models with that of a screening score model based on logistic regression analysis for prediabetes that had been developed previously. The SVM model showed the areas under the curve of 0.731 in the external datasets, which is higher than those of the ANN model (0.729 and the screening score model (0.712, respectively. The prescreening methods developed in this study performed better than the screening score model that had been developed previously and may be more effective method for prediabetes screening.
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Freebairn, L; Atkinson, J; Kelly, P; McDonnell, G; Rychetnik, L
2016-09-21
Evidence-informed decision-making is essential to ensure that health programs and services are effective and offer value for money; however, barriers to the use of evidence persist. Emerging systems science approaches and advances in technology are providing new methods and tools to facilitate evidence-based decision-making. Simulation modelling offers a unique tool for synthesising and leveraging existing evidence, data and expert local knowledge to examine, in a robust, low risk and low cost way, the likely impact of alternative policy and service provision scenarios. This case study will evaluate participatory simulation modelling to inform the prevention and management of gestational diabetes mellitus (GDM). The risks associated with GDM are well recognised; however, debate remains regarding diagnostic thresholds and whether screening and treatment to reduce maternal glucose levels reduce the associated risks. A diagnosis of GDM may provide a leverage point for multidisciplinary lifestyle modification interventions. This research will apply and evaluate a simulation modelling approach to understand the complex interrelation of factors that drive GDM rates, test options for screening and interventions, and optimise the use of evidence to inform policy and program decision-making. The study design will use mixed methods to achieve the objectives. Policy, clinical practice and research experts will work collaboratively to develop, test and validate a simulation model of GDM in the Australian Capital Territory (ACT). The model will be applied to support evidence-informed policy dialogues with diverse stakeholders for the management of GDM in the ACT. Qualitative methods will be used to evaluate simulation modelling as an evidence synthesis tool to support evidence-based decision-making. Interviews and analysis of workshop recordings will focus on the participants' engagement in the modelling process; perceived value of the participatory process, perceived
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Directory of Open Access Journals (Sweden)
Siemers Eric R
2010-04-01
Full Text Available Abstract Background Alzheimer's Disease (AD affects a growing proportion of the population each year. Novel therapies on the horizon may slow the progress of AD symptoms and avoid cases altogether. Initiating treatment for the underlying pathology of AD would ideally be based on biomarker screening tools identifying pre-symptomatic individuals. Early-stage modeling provides estimates of potential outcomes and informs policy development. Methods A time-to-event (TTE simulation provided estimates of screening asymptomatic patients in the general population age ≥55 and treatment impact on the number of patients reaching AD. Patients were followed from AD screen until all-cause death. Baseline sensitivity and specificity were 0.87 and 0.78, with treatment on positive screen. Treatment slowed progression by 50%. Events were scheduled using literature-based age-dependent incidences of AD and death. Results The base case results indicated increased AD free years (AD-FYs through delays in onset and a reduction of 20 AD cases per 1000 screened individuals. Patients completely avoiding AD accounted for 61% of the incremental AD-FYs gained. Total years of treatment per 1000 screened patients was 2,611. The number-needed-to-screen was 51 and the number-needed-to-treat was 12 to avoid one case of AD. One-way sensitivity analysis indicated that duration of screening sensitivity and rescreen interval impact AD-FYs the most. A two-way sensitivity analysis found that for a test with an extended duration of sensitivity (15 years the number of AD cases avoided was 6,000-7,000 cases for a test with higher sensitivity and specificity (0.90,0.90. Conclusions This study yielded valuable parameter range estimates at an early stage in the study of screening for AD. Analysis identified duration of screening sensitivity as a key variable that may be unavailable from clinical trials.
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Furiak, Nicolas M; Klein, Robert W; Kahle-Wrobleski, Kristin; Siemers, Eric R; Sarpong, Eric; Klein, Timothy M
2010-04-30
Alzheimer's Disease (AD) affects a growing proportion of the population each year. Novel therapies on the horizon may slow the progress of AD symptoms and avoid cases altogether. Initiating treatment for the underlying pathology of AD would ideally be based on biomarker screening tools identifying pre-symptomatic individuals. Early-stage modeling provides estimates of potential outcomes and informs policy development. A time-to-event (TTE) simulation provided estimates of screening asymptomatic patients in the general population age > or =55 and treatment impact on the number of patients reaching AD. Patients were followed from AD screen until all-cause death. Baseline sensitivity and specificity were 0.87 and 0.78, with treatment on positive screen. Treatment slowed progression by 50%. Events were scheduled using literature-based age-dependent incidences of AD and death. The base case results indicated increased AD free years (AD-FYs) through delays in onset and a reduction of 20 AD cases per 1000 screened individuals. Patients completely avoiding AD accounted for 61% of the incremental AD-FYs gained. Total years of treatment per 1000 screened patients was 2,611. The number-needed-to-screen was 51 and the number-needed-to-treat was 12 to avoid one case of AD. One-way sensitivity analysis indicated that duration of screening sensitivity and rescreen interval impact AD-FYs the most. A two-way sensitivity analysis found that for a test with an extended duration of sensitivity (15 years) the number of AD cases avoided was 6,000-7,000 cases for a test with higher sensitivity and specificity (0.90,0.90). This study yielded valuable parameter range estimates at an early stage in the study of screening for AD. Analysis identified duration of screening sensitivity as a key variable that may be unavailable from clinical trials.
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Screening Mammography: Science, Policy and Politics–The Good, the Bad and the Ugly
Diana Petitti, MD, MPH, FACPM, an epidemiologic expert on women's health and evidence based medicine, with posts as vice chair and spokesperson for the U.S. Preventive Service Task Force, presented "Screening Mammography: Science, Policy and Politics–The Good, the Bad and the Ugly."
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Breast Cancer Screening in an Era of Personalized Regimens
Onega, Tracy; Beaber, Elisabeth F.; Sprague, Brian L.; Barlow, William E.; Haas, Jennifer S.; Tosteson, Anna N.A.; Schnall, Mitchell D.; Armstrong, Katrina; Schapira, Marilyn M.; Geller, Berta; Weaver, Donald L.; Conant, Emily F.
2014-01-01
Breast cancer screening holds a prominent place in public health, health care delivery, policy, and women’s health care decisions. Several factors are driving shifts in how population-based breast cancer screening is approached, including advanced imaging technologies, health system performance measures, health care reform, concern for “overdiagnosis,” and improved understanding of risk. Maximizing benefits while minimizing the harms of screening requires moving from a “1-size-fits-all” guideline paradigm to more personalized strategies. A refined conceptual model for breast cancer screening is needed to align women’s risks and preferences with screening regimens. A conceptual model of personalized breast cancer screening is presented herein that emphasizes key domains and transitions throughout the screening process, as well as multilevel perspectives. The key domains of screening awareness, detection, diagnosis, and treatment and survivorship are conceptualized to function at the level of the patient, provider, facility, health care system, and population/policy arena. Personalized breast cancer screening can be assessed across these domains with both process and outcome measures. Identifying, evaluating, and monitoring process measures in screening is a focus of a National Cancer Institute initiative entitled PROSPR (Population-based Research Optimizing Screening through Personalized Regimens), which will provide generalizable evidence for a risk-based model of breast cancer screening, The model presented builds on prior breast cancer screening models and may serve to identify new measures to optimize benefits-to-harms tradeoffs in population-based screening, which is a timely goal in the era of health care reform. PMID:24830599
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A System Dynamics Model of Serum Prostate-Specific Antigen Screening for Prostate Cancer.
Palma, Anton; Lounsbury, David W; Schlecht, Nicolas F; Agalliu, Ilir
2016-02-01
Since 2012, US guidelines have recommended against prostate-specific antigen (PSA) screening for prostate cancer. However, evidence of screening benefit from the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening trial and the European Randomized Study of Screening for Prostate Cancer has been inconsistent, due partly to differences in noncompliance and contamination. Using system dynamics modeling, we replicated the PLCO trial and extrapolated follow-up to 20 years. We then simulated 3 scenarios correcting for contamination in the PLCO control arm using Surveillance, Epidemiology, and End Results (SEER) incidence and survival data collected prior to the PSA screening era (scenario 1), SEER data collected during the PLCO trial period (1993-2001) (scenario 2), and data from the European trial's control arm (1991-2005) (scenario 3). In all scenarios, noncompliance was corrected using incidence and survival rates for men with screen-detected cancer in the PLCO screening arm. Scenarios 1 and 3 showed a benefit of PSA screening, with relative risks of 0.62 (95% confidence interval: 0.53, 0.72) and 0.70 (95% confidence interval: 0.59, 0.83) for cancer-specific mortality after 20 years, respectively. In scenario 2, however, there was no benefit of screening. This simulation showed that after correcting for noncompliance and contamination, there is potential benefit of PSA screening in reducing prostate cancer mortality. It also demonstrates the utility of system dynamics modeling for synthesizing epidemiologic evidence to inform public policy. © The Author 2015. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
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Risk-Screening Environmental Indicators (RSEI)
U.S. Environmental Protection Agency — EPA’s Risk-Screening Environmental Indicators (RSEI) is a geographically-based model that helps policy makers and communities explore data on releases of toxic...
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Mechanistic modeling for mammography screening risks
International Nuclear Information System (INIS)
Bijwaard, Harmen
2008-01-01
Full text: Western populations show a very high incidence of breast cancer and in many countries mammography screening programs have been set up for the early detection of these cancers. Through these programs large numbers of women (in the Netherlands, 700.000 per year) are exposed to low but not insignificant X-ray doses. ICRP based risk estimates indicate that the number of breast cancer casualties due to mammography screening can be as high as 50 in the Netherlands per year. The number of lives saved is estimated to be much higher, but for an accurate calculation of the benefits of screening a better estimate of these risks is indispensable. Here it is attempted to better quantify the radiological risks of mammography screening through the application of a biologically based model for breast tumor induction by X-rays. The model is applied to data obtained from the National Institutes of Health in the U.S. These concern epidemiological data of female TB patients who received high X-ray breast doses in the period 1930-1950 through frequent fluoroscopy of their lungs. The mechanistic model that is used to describe the increased breast cancer incidence is based on an earlier study by Moolgavkar et al. (1980), in which the natural background incidence of breast cancer was modeled. The model allows for a more sophisticated extrapolation of risks to the low dose X-ray exposures that are common in mammography screening and to the higher ages that are usually involved. Furthermore, it allows for risk transfer to other (non-western) populations. The results have implications for decisions on the frequency of screening, the number of mammograms taken at each screening, minimum and maximum ages for screening and the transfer to digital equipment. (author)
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Wu, Ping-Hsiu; Lin, Yu-Min; Liao, Chao-Sheng; Chang, Hung-Chuen; Chen, Yu-Hung; Yang, Kuo-Ching; Shih, Chia-Hui
2013-06-01
The Taiwanese government has proposed a population-based colorectal tumor detection program for the average-risk population. This study's objectives were to understand the outcomes of these screening policies and to evaluate the effectiveness of the program. We compared two databases compiled in one medical center. The "policy-promoted cancer screening" (PPS) database was built on the basis of the policy of the Taiwan Bureau of National Health Insurance for cancer screening. The "health promotion service" (HPS) database was built to provide health check-ups for self-paid volunteers. Both the PPS and HPS databases employ the immunochemical fecal occult blood test (iFOBT) and colonoscopy for colorectal tumor screening using different strategies. A comparison of outcomes between the PPS and HPS included: (1) quality indicators-compliance rate, cecum reaching rate, and tumor detection rate; and (2) validity indicators-sensitivity, specificity, positive, and negative predictive values for detecting colorectal neoplasms. A total of 10,563 and 1481 individuals were enrolled in PPS and HPS, respectively. Among quality indicators, there was no statistically significant difference in the cecum reaching rate between PPS and HPS. The compliance rates were 56.1% for PPS and 91.8% for HPS (p performance. Copyright © 2013. Published by Elsevier B.V.
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Onega, Tracy; Beaber, Elisabeth F; Sprague, Brian L; Barlow, William E; Haas, Jennifer S; Tosteson, Anna N A; D Schnall, Mitchell; Armstrong, Katrina; Schapira, Marilyn M; Geller, Berta; Weaver, Donald L; Conant, Emily F
2014-10-01
Breast cancer screening holds a prominent place in public health, health care delivery, policy, and women's health care decisions. Several factors are driving shifts in how population-based breast cancer screening is approached, including advanced imaging technologies, health system performance measures, health care reform, concern for "overdiagnosis," and improved understanding of risk. Maximizing benefits while minimizing the harms of screening requires moving from a "1-size-fits-all" guideline paradigm to more personalized strategies. A refined conceptual model for breast cancer screening is needed to align women's risks and preferences with screening regimens. A conceptual model of personalized breast cancer screening is presented herein that emphasizes key domains and transitions throughout the screening process, as well as multilevel perspectives. The key domains of screening awareness, detection, diagnosis, and treatment and survivorship are conceptualized to function at the level of the patient, provider, facility, health care system, and population/policy arena. Personalized breast cancer screening can be assessed across these domains with both process and outcome measures. Identifying, evaluating, and monitoring process measures in screening is a focus of a National Cancer Institute initiative entitled PROSPR (Population-based Research Optimizing Screening through Personalized Regimens), which will provide generalizable evidence for a risk-based model of breast cancer screening, The model presented builds on prior breast cancer screening models and may serve to identify new measures to optimize benefits-to-harms tradeoffs in population-based screening, which is a timely goal in the era of health care reform. © 2014 American Cancer Society.
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From Predictive Models to Instructional Policies
Rollinson, Joseph; Brunskill, Emma
2015-01-01
At their core, Intelligent Tutoring Systems consist of a student model and a policy. The student model captures the state of the student and the policy uses the student model to individualize instruction. Policies require different properties from the student model. For example, a mastery threshold policy requires the student model to have a way…
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Directory of Open Access Journals (Sweden)
Ping-Hsiu Wu
2013-06-01
Conclusion: In comparison with the outcomes of the HPS database, the screening efficacy of the PPS database is even for detecting colorectal carcinoma but is limited in detecting advanced adenoma. HPS may provide comprehensive validity indicators and will be helpful in adjusting current policies for improving screening performance.
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Siebert, Uwe; Sroczynski, Gaby; Hillemanns, Peter; Engel, Jutta; Stabenow, Roland; Stegmaier, Christa; Voigt, Kerstin; Gibis, Bernhard; Hölzel, Dieter; Goldie, Sue J
2006-04-01
We sought to develop and validate a decision-analytic model for the natural history of cervical cancer for the German health care context and to apply it to cervical cancer screening. We developed a Markov model for the natural history of cervical cancer and cervical cancer screening in the German health care context. The model reflects current German practice standards for screening, diagnostic follow-up and treatment regarding cervical cancer and its precursors. Data for disease progression and cervical cancer survival were obtained from the literature and German cancer registries. Accuracy of Papanicolaou (Pap) testing was based on meta-analyses. We performed internal and external model validation using observed epidemiological data for unscreened women from different German cancer registries. The model predicts life expectancy, incidence of detected cervical cancer cases, lifetime cervical cancer risks and mortality. The model predicted a lifetime cervical cancer risk of 3.0% and a lifetime cervical cancer mortality of 1.0%, with a peak cancer incidence of 84/100,000 at age 51 years. These results were similar to observed data from German cancer registries, German literature data and results from other international models. Based on our model, annual Pap screening could prevent 98.7% of diagnosed cancer cases and 99.6% of deaths due to cervical cancer in women completely adherent to screening and compliant to treatment. Extending the screening interval from 1 year to 2, 3 or 5 years resulted in reduced screening effectiveness. This model provides a tool for evaluating the long-term effectiveness of different cervical cancer screening tests and strategies.
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Parker, Lisa
2017-07-01
Values are an important part of evidence-based decision making for health policy: they guide the type of evidence that is collected, how it is interpreted, and how important the conclusions are considered to be. Experts in breast screening (including clinicians, researchers, consumer advocates and senior administrators) hold differing values in relation to what is important in breast screening policy and practice, and committees may find it difficult to incorporate the complexity and variety of values into policy decisions. The decision making tool provided here is intended to assist with this process. The tool is modified from more general frameworks that are intended to assist with ethical decision making in public health, and informed by data drawn from previous empirical studies on values amongst Australian breast screening experts. It provides a structured format for breast screening committees to consider and discuss the values of themselves and others, suggests relevant topics for further inquiry and highlights areas of need for future research into the values of the public. It enables committees to publicly explain and justify their decisions with reference to values, improving transparency and accountability. It is intended to act alongside practices that seek to accommodate the values of individual women in the informed decision making process for personal decision making about participation in breast screening. Copyright © 2017 Elsevier B.V. All rights reserved.
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Richter, C.; Beest, G.T.; Sancak, I.; Aydinly, R.; Bulbul, K.; Laetemia-Tomata, F.; De Leeuw, M.; Waegemaekers, T.; Swanink, C.; Roovers, E.
2012-01-01
Despite the increased prevalence of hepatitis B and C in most migrant groups in The Netherlands, a national screening policy for these infections is not available. In order to estimate the prevalence of hepatitis B and C in the largest group of first-generation migrants (FGM) in The Netherlands, we
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Directory of Open Access Journals (Sweden)
Ortendahl Jesse
2007-10-01
Full Text Available Abstract Background To provide quantitative insight into current U.S. policy choices for cervical cancer prevention, we developed a model of human papillomavirus (HPV and cervical cancer, explicitly incorporating uncertainty about the natural history of disease. Methods We developed a stochastic microsimulation of cervical cancer that distinguishes different HPV types by their incidence, clearance, persistence, and progression. Input parameter sets were sampled randomly from uniform distributions, and simulations undertaken with each set. Through systematic reviews and formal data synthesis, we established multiple epidemiologic targets for model calibration, including age-specific prevalence of HPV by type, age-specific prevalence of cervical intraepithelial neoplasia (CIN, HPV type distribution within CIN and cancer, and age-specific cancer incidence. For each set of sampled input parameters, likelihood-based goodness-of-fit (GOF scores were computed based on comparisons between model-predicted outcomes and calibration targets. Using 50 randomly resampled, good-fitting parameter sets, we assessed the external consistency and face validity of the model, comparing predicted screening outcomes to independent data. To illustrate the advantage of this approach in reflecting parameter uncertainty, we used the 50 sets to project the distribution of health outcomes in U.S. women under different cervical cancer prevention strategies. Results Approximately 200 good-fitting parameter sets were identified from 1,000,000 simulated sets. Modeled screening outcomes were externally consistent with results from multiple independent data sources. Based on 50 good-fitting parameter sets, the expected reductions in lifetime risk of cancer with annual or biennial screening were 76% (range across 50 sets: 69–82% and 69% (60–77%, respectively. The reduction from vaccination alone was 75%, although it ranged from 60% to 88%, reflecting considerable parameter
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Chan, Dorothy N S; So, Winnie K W
Cervical cancer can be prevented by effective screening using Papanicolaou tests, but the utilization rate is lower among ethnic minorities than in the general population. Understanding the factors influencing minorities' use of such screening can aid the design of an appropriate intervention to increase their uptake rate. The aims of this study were to examine the factors that influence ethnic minority women in using cervical cancer screening and the similarities and differences in associated factors across different groups and to explore the interrelationships between the factors identified. A literature search was conducted using Ovid MEDLINE, Cumulative Index to Nursing and Allied Health Literature Plus, Scopus, PsycINFO, and PubMed. Furthermore, 1390 articles were retrieved, of which 24 met the inclusion criteria. Critical appraisal was performed by means of a quality assessment tool. The findings were summarized in tabular and narrative forms. The findings showed that certain factors commonly affected ethnic minority women's screening behavior, including knowledge, attitude and perceptions, physician's recommendation, quality of care and service, language, and acculturation. Culture-related factors, religion, and acculturation exhibited close interrelationships with the attitude and perceptions factor, resulting in behavioral change. The review sheds light on how common or unique are the factors across ethnic minorities and how these factors interact to influence behavior. Further studies are warranted to develop and test empirically a comprehensive model leading to a better understanding of the interrelationships between multiple factors. The model should be useful in informing policy makers about appropriate resource allocation and in guiding the development of culturally relevant programs to increase screening uptake.
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Screen or not to screen for peripheral arterial disease: guidance from a decision model.
Vaidya, Anil; Joore, Manuela A; Ten Cate-Hoek, Arina J; Ten Cate, Hugo; Severens, Johan L
2014-01-29
Asymptomatic Peripheral Arterial Disease (PAD) is associated with greater risk of acute cardiovascular events. This study aims to determine the cost-effectiveness of one time only PAD screening using Ankle Brachial Index (ABI) test and subsequent anti platelet preventive treatment (low dose aspirin or clopidogrel) in individuals at high risk for acute cardiovascular events compared to no screening and no treatment using decision analytic modelling. A probabilistic Markov model was developed to evaluate the life time cost-effectiveness of the strategy of selective PAD screening and consequent preventive treatment compared to no screening and no preventive treatment. The analysis was conducted from the Dutch societal perspective and to address decision uncertainty, probabilistic sensitivity analysis was performed. Results were based on average values of 1000 Monte Carlo simulations and using discount rates of 1.5% and 4% for effects and costs respectively. One way sensitivity analyses were performed to identify the two most influential model parameters affecting model outputs. Then, a two way sensitivity analysis was conducted for combinations of values tested for these two most influential parameters. For the PAD screening strategy, life years and quality adjusted life years gained were 21.79 and 15.66 respectively at a lifetime cost of 26,548 Euros. Compared to no screening and treatment (20.69 life years, 15.58 Quality Adjusted Life Years, 28,052 Euros), these results indicate that PAD screening and treatment is a dominant strategy. The cost effectiveness acceptability curves show 88% probability of PAD screening being cost effective at the Willingness To Pay (WTP) threshold of 40000 Euros. In a scenario analysis using clopidogrel as an alternative anti-platelet drug, PAD screening strategy remained dominant. This decision analysis suggests that targeted ABI screening and consequent secondary prevention of cardiovascular events using low dose aspirin or
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Economic Models as Devices of Policy Change
DEFF Research Database (Denmark)
Henriksen, Lasse Folke
2013-01-01
Can the emergence of a new policy model be a catalyst for a paradigm shift in the overall interpretative framework of how economic policy is conducted within a society? This paper claims that models are understudied as devices used by actors to induce policy change. This paper explores the role...... of models in Danish economic policy, where, from the 1970s onwards, executive public servants in this area have exclusively been specialists in model design. To understand changes in economic policy, this paper starts with a discussion of whether the notion of paradigm shift is adequate. It then examines...... the extent to which the performativity approach can help identify macroscopic changes in policy from seemingly microscopic changes in policy models. The concept of performativity is explored as a means of thinking about the constitution of agency directed at policy change. The paper brings this concept...
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Policy modeling for industrial energy use
Energy Technology Data Exchange (ETDEWEB)
Worrell, Ernst; Park, Hi-Chun; Lee, Sang-Gon; Jung, Yonghun; Kato, Hiroyuki; Ramesohl, Stephan; Boyd, Gale; Eichhammer, Wolfgang; Nyboer, John; Jaccard, Mark; Nordqvist, Joakim; Boyd, Christopher; Klee, Howard; Anglani, Norma; Biermans, Gijs
2003-03-01
The international workshop on Policy Modeling for Industrial Energy Use was jointly organized by EETA (Professional Network for Engineering Economic Technology Analysis) and INEDIS (International Network for Energy Demand Analysis in the Industrial Sector). The workshop has helped to layout the needs and challenges to include policy more explicitly in energy-efficiency modeling. The current state-of-the-art models have a proven track record in forecasting future trends under conditions similar to those faced in the recent past. However, the future of energy policy in a climate-restrained world is likely to demand different and additional services to be provided by energy modelers. In this workshop some of the international models used to make energy consumption forecasts have been discussed as well as innovations to enable the modeling of policy scenarios. This was followed by the discussion of future challenges, new insights in the data needed to determine the inputs into energy model s, and methods to incorporate decision making and policy in the models. Based on the discussion the workshop participants came to the following conclusions and recommendations: Current energy models are already complex, and it is already difficult to collect the model inputs. Hence, new approaches should be transparent and not lead to extremely complex models that try to ''do everything''. The model structure will be determined by the questions that need to be answered. A good understanding of the decision making framework of policy makers and clear communication on the needs are essential to make any future energy modeling effort successful. There is a need to better understand the effects of policy on future energy use, emissions and the economy. To allow the inclusion of policy instruments in models, evaluation of programs and instruments is essential, and need to be included in the policy instrument design. Increased efforts are needed to better understand the
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The impact of aviation checkpoint queues on optimizing security screening effectiveness
Energy Technology Data Exchange (ETDEWEB)
Lee, Adrian J., E-mail: ajlee@citeri.or [Central Illinois Technology and Education Research Institute, 2312 Connie Drive, Springfield, IL 62704-8722 (United States); Jacobson, Sheldon H., E-mail: shj@illinois.ed [Department of Computer Science, University of Illinois at Urbana-Champaign, 201 N. Goodwin Ave. M/C 258, Urbana, IL 61801-2302 (United States)
2011-08-15
Passenger screening at aviation security checkpoints is a critical component in protecting airports and aircraft from terrorist threats. Recent developments in screening device technology have increased the ability to detect these threats; however, the average amount of time it takes to screen a passenger still remains a concern. This paper models the queueing process for a multi-level airport checkpoint security system, where multiple security classes are formed through subsets of specialized screening devices. An optimal static assignment policy is obtained which minimizes the steady-state expected amount of time a passenger spends in the security system. Then, an optimal dynamic assignment policy is obtained through a transient analysis that balances the expected number of true alarms with the expected amount of time a passenger spends in the security system. Performance of a two-class system is compared to that of a selective security system containing primary and secondary levels of screening. The key contribution is that the resulting optimal assignment policies increase security and passenger throughput by efficiently and effectively utilizing available screening resources.
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The impact of aviation checkpoint queues on optimizing security screening effectiveness
International Nuclear Information System (INIS)
Lee, Adrian J.; Jacobson, Sheldon H.
2011-01-01
Passenger screening at aviation security checkpoints is a critical component in protecting airports and aircraft from terrorist threats. Recent developments in screening device technology have increased the ability to detect these threats; however, the average amount of time it takes to screen a passenger still remains a concern. This paper models the queueing process for a multi-level airport checkpoint security system, where multiple security classes are formed through subsets of specialized screening devices. An optimal static assignment policy is obtained which minimizes the steady-state expected amount of time a passenger spends in the security system. Then, an optimal dynamic assignment policy is obtained through a transient analysis that balances the expected number of true alarms with the expected amount of time a passenger spends in the security system. Performance of a two-class system is compared to that of a selective security system containing primary and secondary levels of screening. The key contribution is that the resulting optimal assignment policies increase security and passenger throughput by efficiently and effectively utilizing available screening resources.
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Beaber, Elisabeth F; Kim, Jane J; Schapira, Marilyn M; Tosteson, Anna N A; Zauber, Ann G; Geiger, Ann M; Kamineni, Aruna; Weaver, Donald L; Tiro, Jasmin A
2015-06-01
General frameworks of the cancer screening process are available, but none directly compare the process in detail across different organ sites. This limits the ability of medical and public health professionals to develop and evaluate coordinated screening programs that apply resources and population management strategies available for one cancer site to other sites. We present a trans-organ conceptual model that incorporates a single screening episode for breast, cervical, and colorectal cancers into a unified framework based on clinical guidelines and protocols; the model concepts could be expanded to other organ sites. The model covers four types of care in the screening process: risk assessment, detection, diagnosis, and treatment. Interfaces between different provider teams (eg, primary care and specialty care), including communication and transfer of responsibility, may occur when transitioning between types of care. Our model highlights across each organ site similarities and differences in steps, interfaces, and transitions in the screening process and documents the conclusion of a screening episode. This model was developed within the National Cancer Institute-funded consortium Population-based Research Optimizing Screening through Personalized Regimens (PROSPR). PROSPR aims to optimize the screening process for breast, cervical, and colorectal cancer and includes seven research centers and a statistical coordinating center. Given current health care reform initiatives in the United States, this conceptual model can facilitate the development of comprehensive quality metrics for cancer screening and promote trans-organ comparative cancer screening research. PROSPR findings will support the design of interventions that improve screening outcomes across multiple cancer sites. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.
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Directory of Open Access Journals (Sweden)
Inwon Kang
2018-01-01
Full Text Available Firms often superficially adopt policies because of governmental rules and regulations, so as to avoid penalties or to gain benefits. However, the evaluation and characterization of those kinds of adoptions as policy performance distorts the true level of policy performance: social sustainability. This study proposes an affective policy performance evaluation model. The attitudes of employees toward adopting a policy are characterized into genuine and superficial compliance. Their behaviors are explained through voluntary and opportunistic adoptions. In order to validate the proposed model, a survey was conducted on an international trade policy target group (n = 216 for the Strategic Trade Control System (STCS, in order to understand their attitudes toward adopting the policy. The survey data was analyzed by a structural equation modeling method. The measures of the factors in the proposed model are adopted and modified from existing studies. The most effective resources of policy implementation on the firms’ genuine and superficial compliance and ultimately on the firms’ voluntary policy adoption are revealed through the analysis. Based on the results, this study presents a strategy for allocating and managing policy implementation resources to exclusively encourage firms’ trade policy adoptions.
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Towards increased policy relevance in energy modeling
Energy Technology Data Exchange (ETDEWEB)
Worrell, Ernst; Ramesohl, Stephan; Boyd, Gale
2003-07-29
Historically, most energy models were reasonably equipped to assess the impact of a subsidy or change in taxation, but are often insufficient to assess the impact of more innovative policy instruments. We evaluate the models used to assess future energy use, focusing on industrial energy use. We explore approaches to engineering-economic analysis that could help improve the realism and policy relevance of engineering-economic modeling frameworks. We also explore solutions to strengthen the policy usefulness of engineering-economic analysis that can be built from a framework of multi-disciplinary cooperation. We focus on the so-called ''engineering-economic'' (or ''bottom-up'') models, as they include the amount of detail that is commonly needed to model policy scenarios. We identify research priorities for the modeling framework, technology representation in models, policy evaluation and modeling of decision-making behavior.
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Screening fifth forces in k-essence and DBI models
Energy Technology Data Exchange (ETDEWEB)
Brax, Philippe [Institut de Physique Théorique, CEA, IPhT, CNRS, URA2306, F-91191 Gif-sur-Yvette cédex (France); Burrage, Clare [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom); Davis, Anne-Christine, E-mail: Philippe.Brax@cea.fr, E-mail: Clare.Burrage@nottingham.ac.uk, E-mail: A.C.Davis@damtp.cam.ac.uk [Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, Cambridge CB3 0WA (United Kingdom)
2013-01-01
New fifth forces have not yet been detected in the laboratory or in the solar system, hence it is typically difficult to introduce new light scalar fields that would mediate such forces. In recent years it has been shown that a number of non-linear scalar field theories allow for a dynamical mechanism, such as the Vainshtein and chameleon ones, that suppresses the strength of the scalar fifth force in experimental environments. This is known as screening, however it is unclear how common screening is within non-linear scalar field theories. k-essence models are commonly studied examples of non-linear models, with DBI as the best motivated example, and so we ask whether these non-linearities are able to screen a scalar fifth force. We find that a Vainshtein-like screening mechanism exists for such models although with limited applicability. For instance, we cannot find a screening mechanism for DBI models. On the other hand, we construct a large class of k-essence models which lead to the acceleration of the Universe in the recent past for which the fifth force mediated by the scalar can be screened.
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Evidence for the credibility of health economic models for health policy decision-making
DEFF Research Database (Denmark)
Søgaard, Rikke; Lindholt, Jes S.
2012-01-01
OBJECTIVE: To investigate whether the credibility of health economic models of screening for abdominal aortic aneurysms for health policy decision-making has improved since 2005 when a systematic review by Campbell et al. concluded that reporting standards were poor and there was divergence between...... benefited from general advances in health economic modelling and some improvements in reporting were noted. However, the low level of agreement between studies in model structures and assumptions, and difficulty in justifying these (convergent validity), remain a threat to the credibility of health economic...... models. Decision-makers should not accept the results of a modelling study if the methods are not fully transparent and justified. Modellers should, whenever relevant, supplement a primary report of results with a technical report detailing and discussing the methodological choices made....
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Lingley, Leslie; Slaughter, Stephen L.; Sarikhan, Isabelle Y.; Norman, David K.
2013-02-01
This discussion is in response to the article entitled "Comparison of slope stability screening tools following a large storm event and application to forest management and policy" by Kara Whittaker and Dan McShane (Geomorphology 145-146 (2012) 115-122). The discussion is coauthored by several geologists at the Washington Department of Natural Resources (WDNR) including those from the research and policy sections of the state agency.
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[Cost-effectiveness of breast cancer screening policies in Mexico].
Valencia-Mendoza, Atanacio; Sánchez-González, Gilberto; Bautista-Arredondo, Sergio; Torres-Mejía, Gabriela; Bertozzi, Stefano M
2009-01-01
Generate cost-effectiveness information to allow policy makers optimize breast cancer (BC) policy in Mexico. We constructed a Markov model that incorporates four interrelated processes of the disease: the natural history; detection using mammography; treatment; and other competing-causes mortality, according to which 13 different strategies were modeled. Strategies (starting age, % of coverage, frequency in years)= (48, 25, 2), (40, 50, 2) and (40, 50, 1) constituted the optimal method for expanding the BC program, yielding 75.3, 116.4 and 171.1 thousand pesos per life-year saved, respectively. The strategies included in the optimal method for expanding the program produce a cost per life-year saved of less than two times the GNP per capita and hence are cost-effective according to WHO Commission on Macroeconomics and Health criteria.
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Vos, Bénédicte; Lagasse, Raphaël; Levêque, Alain
2014-07-01
The Kingdon model, based on the convergence of three streams (problem, policy, and politics) and the opening of a policy window, analyses the process by which a health issue is placed on the political agenda. We used this model to document the political agenda-setting process of the newborn hearing screening programme in Belgium. A qualitative study based on a document review and on semi-directed interviews was carried out. The interviews were conducted with nine people who had played a role in putting the issue in question on the political agenda, and the documents reviewed included scientific literature and internal reports and publications from the newborn hearing screening programme. The thematic analysis of the data collected was carried out on the basis of the Kingdon model's three streams. The political agenda-setting of this screening programme was based on many factors. The problem stream included factors external to the context under study, such as the technological developments and the contribution of the scientific literature which led to the recommendation to provide newborn hearing screening. The two other streams (policy and politics) covered factors internal to the Belgian context. The fact that it was locally feasible with financial support, the network of doctors convinced of the need for newborn hearing screening, the drafting of various proposals, and the search for financing were all part of the policy stream. The Belgian political context and the policy opportunities concerning preventive medicine were identified as significant factors in the third stream. When these three streams converged, a policy window opened, allowing newborn hearing screening onto the political agenda and enabling the policy decision for its introduction. The advantage of applying the Kingdon model in our approach was the ability to demonstrate the political agenda-setting process, using the three streams. This made it possible to identify the many factors involved in
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Business-as-Unusual: Existing policies in energy model baselines
International Nuclear Information System (INIS)
Strachan, Neil
2011-01-01
Baselines are generally accepted as a key input assumption in long-term energy modelling, but energy models have traditionally been poor on identifying baselines assumptions. Notably, transparency on the current policy content of model baselines is now especially critical as long-term climate mitigation policies have been underway for a number of years. This paper argues that the range of existing energy and emissions policies are an integral part of any long-term baseline, and hence already represent a 'with-policy' baseline, termed here a Business-as-Unusual (BAuU). Crucially, existing energy policies are not a sunk effort; as impacts of existing policy initiatives are targeted at future years, they may be revised through iterative policy making, and their quantitative effectiveness requires ex-post verification. To assess the long-term role of existing policies in energy modelling, currently identified UK policies are explicitly stripped out of the UK MARKAL Elastic Demand (MED) optimisation energy system model, to generate a BAuU (with-policy) and a REF (without policy) baseline. In terms of long-term mitigation costs, policy-baseline assumptions are comparable to another key exogenous modelling assumption - that of global fossil fuel prices. Therefore, best practice in energy modelling would be to have both a no-policy reference baseline, and a current policy reference baseline (BAuU). At a minimum, energy modelling studies should have a transparent assessment of the current policy contained within the baseline. Clearly identifying and comparing policy-baseline assumptions are required for cost effective and objective policy making, otherwise energy models will underestimate the true cost of long-term emissions reductions.
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Gwyther, Holly; Shaw, Rachel; Jaime Dauden, Eva-Amparo; D'Avanzo, Barbara; Kurpas, Donata; Bujnowska-Fedak, Maria; Kujawa, Tomasz; Marcucci, Maura; Cano, Antonio; Holland, Carol
2018-01-13
To elicit European healthcare policy-makers' views, understanding and attitudes about the implementation of frailty screening and management strategies and responses to stakeholders' views. Thematic analysis of semistructured qualitative interviews. European healthcare policy departments. Seven European healthcare policy-makers representing the European Union (n=2), UK (n=2), Italy (n=1), Spain (n=1) and Poland (n=1). Participants were sourced through professional networks and the European Commission Authentication Service website and were required to be in an active healthcare policy or decision-making role. Seven themes were identified. Our findings reveal a 'knowledge gap', around frailty and awareness of the malleability of frailty, which has resulted in restricted ownership of frailty by specialists. Policy-makers emphasised the need to recognise frailty as a clinical syndrome but stressed that it should be managed via an integrated and interdisciplinary response to chronicity and ageing. That is, through social co-production. This would require a culture shift in care with redeployment of existing resources to deliver frailty management and intervention services. Policy-makers proposed barriers to a culture shift, indicating a need to be innovative with solutions to empower older adults to optimise their health and well-being, while still fully engaging in the social environment. The cultural acceptance of an integrated care system theme described the complexities of institutional change management, as well as cultural issues relating to working democratically, while in signposting adult care , the need for a personal navigator to help older adults to access appropriate services was proposed. Policy-makers also believed that screening for frailty could be an effective tool for frailty management. There is potential for frailty to be managed in a more integrated and person-centred manner, overcoming the challenges associated with niche ownership within the
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Directory of Open Access Journals (Sweden)
Kevin Ten Haaf
2017-04-01
slightly higher specificity for some models. The PLCOm2012, Bach, and Two-Stage Clonal Expansion incidence models had the best overall performance, with AUCs >0.68 in the NLST and >0.77 in the PLCO. These three models had the highest sensitivity and specificity for predicting 6-y lung cancer incidence in the PLCO chest radiography arm, with sensitivities >79.8% and specificities >62.3%. In contrast, the NLST eligibility criteria yielded a sensitivity of 71.4% and a specificity of 62.2%. Limitations of this study include the lack of identification of optimal risk thresholds, as this requires additional information on the long-term benefits (e.g., life-years gained and mortality reduction and harms (e.g., overdiagnosis of risk-based screening strategies using these models. In addition, information on some predictor variables included in the risk prediction models was not available.Selection of individuals for lung cancer screening using individual risk is superior to selection criteria based on age and pack-years alone. The benefits, harms, and feasibility of implementing lung cancer screening policies based on risk prediction models should be assessed and compared with those of current recommendations.
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Modeling granular phosphor screens by Monte Carlo methods
International Nuclear Information System (INIS)
Liaparinos, Panagiotis F.; Kandarakis, Ioannis S.; Cavouras, Dionisis A.; Delis, Harry B.; Panayiotakis, George S.
2006-01-01
The intrinsic phosphor properties are of significant importance for the performance of phosphor screens used in medical imaging systems. In previous analytical-theoretical and Monte Carlo studies on granular phosphor materials, values of optical properties, and light interaction cross sections were found by fitting to experimental data. These values were then employed for the assessment of phosphor screen imaging performance. However, it was found that, depending on the experimental technique and fitting methodology, the optical parameters of a specific phosphor material varied within a wide range of values, i.e., variations of light scattering with respect to light absorption coefficients were often observed for the same phosphor material. In this study, x-ray and light transport within granular phosphor materials was studied by developing a computational model using Monte Carlo methods. The model was based on the intrinsic physical characteristics of the phosphor. Input values required to feed the model can be easily obtained from tabulated data. The complex refractive index was introduced and microscopic probabilities for light interactions were produced, using Mie scattering theory. Model validation was carried out by comparing model results on x-ray and light parameters (x-ray absorption, statistical fluctuations in the x-ray to light conversion process, number of emitted light photons, output light spatial distribution) with previous published experimental data on Gd 2 O 2 S:Tb phosphor material (Kodak Min-R screen). Results showed the dependence of the modulation transfer function (MTF) on phosphor grain size and material packing density. It was predicted that granular Gd 2 O 2 S:Tb screens of high packing density and small grain size may exhibit considerably better resolution and light emission properties than the conventional Gd 2 O 2 S:Tb screens, under similar conditions (x-ray incident energy, screen thickness)
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Evaluating Energy Efficiency Policies with Energy-Economy Models
Energy Technology Data Exchange (ETDEWEB)
Mundaca, Luis; Neij, Lena; Worrell, Ernst; McNeil, Michael A.
2010-08-01
The growing complexities of energy systems, environmental problems and technology markets are driving and testing most energy-economy models to their limits. To further advance bottom-up models from a multidisciplinary energy efficiency policy evaluation perspective, we review and critically analyse bottom-up energy-economy models and corresponding evaluation studies on energy efficiency policies to induce technological change. We use the household sector as a case study. Our analysis focuses on decision frameworks for technology choice, type of evaluation being carried out, treatment of market and behavioural failures, evaluated policy instruments, and key determinants used to mimic policy instruments. Although the review confirms criticism related to energy-economy models (e.g. unrealistic representation of decision-making by consumers when choosing technologies), they provide valuable guidance for policy evaluation related to energy efficiency. Different areas to further advance models remain open, particularly related to modelling issues, techno-economic and environmental aspects, behavioural determinants, and policy considerations.
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Felix, Juan C; Lacey, Michael J; Miller, Jeffrey D; Lenhart, Gregory M; Spitzer, Mark; Kulkarni, Rucha
2016-06-01
Consensus United States cervical cancer screening guidelines recommend use of combination Pap plus human papillomavirus (HPV) testing for women aged 30 to 65 years. An HPV test was approved by the Food and Drug Administration in 2014 for primary cervical cancer screening in women age 25 years and older. Here, we present the results of clinical-economic comparisons of Pap plus HPV mRNA testing including genotyping for HPV 16/18 (co-testing) versus DNA-based primary HPV testing with HPV 16/18 genotyping and reflex cytology (HPV primary) for cervical cancer screening. A health state transition (Markov) model with 1-year cycling was developed using epidemiologic, clinical, and economic data from healthcare databases and published literature. A hypothetical cohort of one million women receiving triennial cervical cancer screening was simulated from ages 30 to 70 years. Screening strategies compared HPV primary to co-testing. Outcomes included total and incremental differences in costs, invasive cervical cancer (ICC) cases, ICC deaths, number of colposcopies, and quality-adjusted life years for cost-effectiveness calculations. Comprehensive sensitivity analyses were performed. In a simulation cohort of one million 30-year-old women modeled up to age 70 years, the model predicted that screening with HPV primary testing instead of co-testing could lead to as many as 2,141 more ICC cases and 2,041 more ICC deaths. In the simulation, co-testing demonstrated a greater number of lifetime quality-adjusted life years (22,334) and yielded $39.0 million in savings compared with HPV primary, thereby conferring greater effectiveness at lower cost. Model results demonstrate that co-testing has the potential to provide improved clinical and economic outcomes when compared with HPV primary. While actual cost and outcome data are evaluated, these findings are relevant to U.S. healthcare payers and women's health policy advocates seeking cost-effective cervical cancer screening
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Currie, Danielle J; Smith, Carl; Jagals, Paul
2018-03-27
Policy and decision-making processes are routinely challenged by the complex and dynamic nature of environmental health problems. System dynamics modelling has demonstrated considerable value across a number of different fields to help decision-makers understand and predict the dynamic behaviour of complex systems in support the development of effective policy actions. In this scoping review we investigate if, and in what contexts, system dynamics modelling is being used to inform policy or decision-making processes related to environmental health. Four electronic databases and the grey literature were systematically searched to identify studies that intersect the areas environmental health, system dynamics modelling, and decision-making. Studies identified in the initial screening were further screened for their contextual, methodological and application-related relevancy. Studies deemed 'relevant' or 'highly relevant' according to all three criteria were included in this review. Key themes related to the rationale, impact and limitation of using system dynamics in the context of environmental health decision-making and policy were analysed. We identified a limited number of relevant studies (n = 15), two-thirds of which were conducted between 2011 and 2016. The majority of applications occurred in non-health related sectors (n = 9) including transportation, public utilities, water, housing, food, agriculture, and urban and regional planning. Applications were primarily targeted at micro-level (local, community or grassroots) decision-making processes (n = 9), with macro-level (national or international) decision-making to a lesser degree. There was significant heterogeneity in the stated rationales for using system dynamics and the intended impact of the system dynamics model on decision-making processes. A series of user-related, technical and application-related limitations and challenges were identified. None of the reported limitations or challenges
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Screening for breast cancer with mammography
DEFF Research Database (Denmark)
Gøtzsche, Peter C; Jørgensen, Karsten Juhl
2013-01-01
A variety of estimates of the benefits and harms of mammographic screening for breast cancer have been published and national policies vary.......A variety of estimates of the benefits and harms of mammographic screening for breast cancer have been published and national policies vary....
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High-throughput screening (HTS) and modeling of the retinoid ...
Presentation at the Retinoids Review 2nd workshop in Brussels, Belgium on the application of high throughput screening and model to the retinoid system Presentation at the Retinoids Review 2nd workshop in Brussels, Belgium on the application of high throughput screening and model to the retinoid system
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Genetic screens in Caenorhabditis elegans models for neurodegenerative diseases
Alvarenga Fernandes Sin, Olga; Michels, Helen; Nollen, Ellen A. A.
2014-01-01
Caenorhabditis elegans comprises unique features that make it an attractive model organism in diverse fields of biology. Genetic screens are powerful to identify genes and C. elegans can be customized to forward or reverse genetic screens and to establish gene function. These genetic screens can be
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Directory of Open Access Journals (Sweden)
Tu Karen
2005-08-01
Full Text Available Abstract Background The use of neonatal screening for cystic fibrosis is widely debated in the United Kingdom and elsewhere, but the evidence available to inform policy is limited. This paper explores the cost-effectiveness of adding screening for cystic fibrosis to an existing routine neonatal screening programme for congenital hypothyroidism and phenylketonuria, under alternative scenarios and assumptions. Methods The study is based on a decision model comparing screening to no screening in terms of a number of outcome measures, including diagnosis of cystic fibrosis, life-time treatment costs, life years and QALYs gained. The setting is a hypothetical UK health region without an existing neonatal screening programme for cystic fibrosis. Results Under initial assumptions, neonatal screening (using an immunoreactive trypsin/DNA two stage screening protocol costs £5,387 per infant diagnosed, or £1.83 per infant screened (1998 costs. Neonatal screening for cystic fibrosis produces an incremental cost-effectiveness of £6,864 per QALY gained, in our base case scenario (an assumed benefit of a 6 month delay in the emergence of symptoms. A difference of 11 months or more in the emergence of symptoms (and mean survival means neonatal screening is both less costly and produces better outcomes than no screening. Conclusion Neonatal screening is expensive as a method of diagnosis. Neonatal screening may be a cost-effective intervention if the hypothesised delays in the onset of symptoms are confirmed. Implementing both antenatal and neonatal screening would undermine potential economic benefits, since a reduction in the birth incidence of cystic fibrosis would reduce the cost-effectiveness of neonatal screening.
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Lung Cancer Screening Participation: Developing a Conceptual Model to Guide Research.
Carter-Harris, Lisa; Davis, Lorie L; Rawl, Susan M
2016-11-01
To describe the development of a conceptual model to guide research focused on lung cancer screening participation from the perspective of the individual in the decision-making process. Based on a comprehensive review of empirical and theoretical literature, a conceptual model was developed linking key psychological variables (stigma, medical mistrust, fatalism, worry, and fear) to the health belief model and precaution adoption process model. Proposed model concepts have been examined in prior research of either lung or other cancer screening behavior. To date, a few studies have explored a limited number of variables that influence screening behavior in lung cancer specifically. Therefore, relationships among concepts in the model have been proposed and future research directions presented. This proposed model is an initial step to support theoretically based research. As lung cancer screening becomes more widely implemented, it is critical to theoretically guide research to understand variables that may be associated with lung cancer screening participation. Findings from future research guided by the proposed conceptual model can be used to refine the model and inform tailored intervention development.
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DEFF Research Database (Denmark)
Boyd, P A; Devigan, C; Khoshnood, B
2008-01-01
tube defects (NTDs) using the EUROCAT database. MAIN OUTCOME MEASURES: Existence of national prenatal screening policies, legal gestation limit for TOPFA, prenatal detection and termination rates for Down's syndrome and NTD. RESULTS: Ten of the 18 countries had a national country-wide policy for Down...... cases. Six of the 18 countries had a legal gestational age limit for TOPFA, and in two countries, termination of pregnancy was illegal at any gestation. CONCLUSIONS: There are large differences in screening policies between countries in Europe. These, as well as organisational and cultural factors...
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Information Security Policy Modeling for Network Security Systems
Directory of Open Access Journals (Sweden)
Dmitry Sergeevich Chernyavskiy
2014-12-01
Full Text Available Policy management for network security systems (NSSs is one of the most topical issues of network security management. Incorrect configurations of NSSs lead to system outages and appearance of vulnerabilities. Moreover, policy management process is a time-consuming task, which includes significant amount of manual work. These factors reduce efficiency of NSSs’ utilization. The paper discusses peculiarities of policy management process and existing approaches to policy modeling, presents a model aimed to formalize policies for NSSs independently on NSSs’ platforms and select the most effective NSSs for implementation of the policies.
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Policy Analysis Screening System (PASS) demonstration: sample queries and terminal instructions
Energy Technology Data Exchange (ETDEWEB)
None
1979-10-16
This document contains the input and output for the Policy Analysis Screening System (PASS) demonstration. This demonstration is stored on a portable disk at the Environmental Impacts Division. Sample queries presented here include: (1) how to use PASS; (2) estimated 1995 energy consumption from Mid-Range Energy-Forecasting System (MEFS) data base; (3) pollution projections from Strategic Environmental Assessment System (SEAS) data base; (4) diesel auto regulations; (5) diesel auto health effects; (6) oil shale health and safety measures; (7) water pollution effects of SRC; (8) acid rainfall from Energy Environmental Statistics (EES) data base; 1990 EIA electric generation by fuel type; sulfate concentrations by Federal region; forecast of 1995 SO/sub 2/ emissions in Region III; and estimated electrical generating capacity in California to 1990. The file name for each query is included.
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Optimal screening and donor management in a public stool bank.
Kazerouni, Abbas; Burgess, James; Burns, Laura J; Wein, Lawrence M
2015-12-17
Fecal microbiota transplantation is an effective treatment for recurrent Clostridium difficile infection and is being investigated as a treatment for other microbiota-associated diseases. To facilitate these activities, an international public stool bank has been created, which screens donors and processes stools in a standardized manner. The goal of this research is to use mathematical modeling and analysis to optimize screening and donor management at the stool bank. Compared to the current policy of screening active donors every 60 days before releasing their quarantined stools for sale, costs can be reduced by 10.3 % by increasing the screening frequency to every 36 days. In addition, the stool production rate varies widely across donors, and using donor-specific screening, where higher producers are screened more frequently, also reduces costs, as does introducing an interim (i.e., between consecutive regular tests) stool test for just rotavirus and C. difficile. We also derive a donor release (i.e., into the system) policy that allows the supply to approximately match an exponentially increasing deterministic demand. More frequent screening, interim screening for rotavirus and C. difficile, and donor-specific screening, where higher stool producers are screened more frequently, are all cost-reducing measures. If screening costs decrease in the future (e.g., as a result of bringing screening in house), a bottleneck for implementing some of these recommendations may be the reluctance of donors to undergo serum screening more frequently than monthly.
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A Multiscale Model Evaluates Screening for Neoplasia in Barrett's Esophagus.
Directory of Open Access Journals (Sweden)
Kit Curtius
2015-05-01
Full Text Available Barrett's esophagus (BE patients are routinely screened for high grade dysplasia (HGD and esophageal adenocarcinoma (EAC through endoscopic screening, during which multiple esophageal tissue samples are removed for histological analysis. We propose a computational method called the multistage clonal expansion for EAC (MSCE-EAC screening model that is used for screening BE patients in silico to evaluate the effects of biopsy sampling, diagnostic sensitivity, and treatment on disease burden. Our framework seamlessly integrates relevant cell-level processes during EAC development with a spatial screening process to provide a clinically relevant model for detecting dysplastic and malignant clones within the crypt-structured BE tissue. With this computational approach, we retain spatio-temporal information about small, unobserved tissue lesions in BE that may remain undetected during biopsy-based screening but could be detected with high-resolution imaging. This allows evaluation of the efficacy and sensitivity of current screening protocols to detect neoplasia (dysplasia and early preclinical EAC in the esophageal lining. We demonstrate the clinical utility of this model by predicting three important clinical outcomes: (1 the probability that small cancers are missed during biopsy-based screening, (2 the potential gains in neoplasia detection probabilities if screening occurred via high-resolution tomographic imaging, and (3 the efficacy of ablative treatments that result in the curative depletion of metaplastic and neoplastic cell populations in BE in terms of the long-term impact on reducing EAC incidence.
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The Effect of Lead Intensification Screens on Film: Modeling and Experiment
International Nuclear Information System (INIS)
Wendt, S.; Gray, J.; Zhou, C.
2004-01-01
A physics-based, intensification screen model, using lead as an example, has been developed. Comparisons to experimental results are shown. The dominant effect in producing the intensification is from photoelectrons ejected from a 24 - 40 micron layer of lead near the film with Compton electrons and the lead fluorescence x-rays contributing less than 10% to the intensification for settings below 300 kvp. The thickness of lead screen for optimal intensification is between 15 and 70 microns depending upon the energy of the photon. This is less than the traditional practice of a 130 microns front screen and 260 microns back screen. The model computes the intensifying effect of lead screens placed in front or in back of a sheet of radiographic film and accounts for the strong energy dependent effects contributing to the intensification. The lead screen model is independent of film type, so the user can select any type of film and any combination of lead thickness for the front and back screens. The model uses energy dependent x-ray photon absorption cross-sections to compute the production of electrons in the lead. A Monte Carlo calculation was used to determine energy dependent electron penetration in the lead and the film. The model calculates electron attenuation in the film emulsion, the film substrate and both front and back lead screens and determines the intensification effect as a function of the energy deposited in the film. For model validation, lead screen intensification was studied with x-ray generator settings ranging from 75 to 320 kvp and using various thicknesses of aluminum and iron attenuators to filter the x-ray beam. A high precision motion control system coupled with a high purity germanium detector was used to study the energy spectra
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Moving communities toward policy change: APPEAL's 4-prong policy change model.
Tong, Elisa K; Lew, Rod
2013-09-01
Policy change is recognized for underlying much of the success of tobacco control. However, there is little evidence and attention on how Asian American and Native Hawaiian and Pacific Islander (AA and NHPI) communities may engage in policy change. Challenges for AA and NHPI communities include the racial/ethnic and geographic diversity, and tobacco data accurately representing the communities. Over the past decade, the Asian Pacific Partners for Empowerment, Advocacy and Leadership (APPEAL) has worked to develop and implement policy change for AA and NHPI communities. This article describes APPEAL's 4-prong policy change model, in the context of its overall strategic framework for policy change with communities that accounts for varying levels of readiness and leadership capacity, and targets four different levels of policy change (community, mainstream institution, legislative, and corporate). The health promotion implication of this framework for tobacco control policy engagement is for improving understanding of effective pathways to policy change, promoting innovative methods for policy analysis, and translating them into effective implementation and sustainability of policy initiatives. The APPEAL strategic framework can transcend into other communities and health topics that ultimately may contribute to the elimination of health disparities.
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Ashing-Giwa, K
1999-01-01
Models of health behavior provide the conceptual bases for most of the breast cancer screening intervention studies. These models were not designed for and have not been adequately tested with African American women. The models discussed in this paper are: The Health Belief Model, the Theory of Reasoned Action/Theory of Planned Behavior, and the Transtheoretical Model. This paper will examine the socio-cultural relevance of these health behavior models, and discuss specific socio-cultural dimensions that are not accounted for by these paradigms. It is critical that researchers include socio-cultural dimensions, such as interconnectedness, health socialization, ecological factors and health care system factors into their intervention models with African American women. Comprehensive and socio-culturally based investigations are necessary to guide the scientific and policy challenge for reducing breast cancer mortality in African American women.
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Regional differences as barriers to body mass index screening described by Ohio school nurses.
Stalter, Ann M; Chaudry, Rosemary V; Polivka, Barbara J
2011-08-01
Body mass index (BMI) screening is advocated by the National Association of School Nurses (NASN). Research identifying barriers to BMI screening in public elementary school settings has been sparse. The purpose of the study was to identify barriers and facilitating factors of BMI screening practices among Ohio school nurses working in suburban, rural, and urban public elementary schools. This descriptive study used focus groups with 25 school nurses in 3 geographic regions of Ohio. An adapted Healthy People 2010 model guided the development of semistructured focus group questions. Nine regional themes related to BMI screening emerged specific to suburban, rural, and/or urban school nurses' experiences with BMI screening practice, policy, school physical environment, school social environment, school risk/protection, and access to quality health care. Key facilitating factors to BMI screening varied by region. Key barriers to BMI screening were a lack of privacy, time, policy, and workload of school nurses. Regionally specific facilitating factors to BMI screening in schools provide opportunities for schools to accentuate the positive and to promote school health. © 2011, American School Health Association.
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Souka, A P; Papastefanou, I; Pilalis, A; Michalitsi, V; Kassanos, D
2012-05-01
third trimester according to the risk estimated by a first-trimester prediction model yielded a detection rate of 79% for a 25% screen-positive rate. Third-trimester ultrasound is effective in screening for SGA in uncomplicated pregnancies. The use of a contingency screening policy can reduce the need for unnecessary examinations. Copyright © 2012 ISUOG. Published by John Wiley & Sons, Ltd.
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Policy modeling for energy efficiency improvement in US industry
International Nuclear Information System (INIS)
Worrell, Ernst; Price, Lynn; Ruth, Michael
2001-01-01
We are at the beginning of a process of evaluating and modeling the contribution of policies to improve energy efficiency. Three recent policy studies trying to assess the impact of energy efficiency policies in the United States are reviewed. The studies represent an important step in the analysis of climate change mitigation strategies. All studies model the estimated policy impact, rather than the policy itself. Often the policy impacts are based on assumptions, as the effects of a policy are not certain. Most models only incorporate economic (or price) tools, which recent studies have proven to be insufficient to estimate the impacts, costs and benefits of mitigation strategies. The reviewed studies are a first effort to capture the effects of non-price policies. The studies contribute to a better understanding of the role of policies in improving energy efficiency and mitigating climate change. All policy scenarios results in substantial energy savings compared to the baseline scenario used, as well as substantial net benefits to the U.S. economy
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A Policy Language for Modelling Recommendations
Abou El Kalam, Anas; Balbiani, Philippe
While current and emergent applications become more and more complex, most of existing security policies and models only consider a yes/no response to the access requests. Consequently, modelling, formalizing and implementing permissions, obligations and prohibitions do not cover the richness of all the possible scenarios. In fact, several applications have access rules with the recommendation access modality. In this paper we focus on the problem of formalizing security policies with recommendation needs. The aim is to provide a generic domain-independent formal system for modelling not only permissions, prohibitions and obligations, but also recommendations. In this respect, we present our logic-based language, the semantics, the truth conditions, our axiomatic as well as inference rules. We also give a representative use case with our specification of recommendation requirements. Finally, we explain how our logical framework could be used to query the security policy and to check its consistency.
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Assessing groundwater policy with coupled economic-groundwater hydrologic modeling
Mulligan, Kevin B.; Brown, Casey; Yang, Yi-Chen E.; Ahlfeld, David P.
2014-03-01
This study explores groundwater management policies and the effect of modeling assumptions on the projected performance of those policies. The study compares an optimal economic allocation for groundwater use subject to streamflow constraints, achieved by a central planner with perfect foresight, with a uniform tax on groundwater use and a uniform quota on groundwater use. The policies are compared with two modeling approaches, the Optimal Control Model (OCM) and the Multi-Agent System Simulation (MASS). The economic decision models are coupled with a physically based representation of the aquifer using a calibrated MODFLOW groundwater model. The results indicate that uniformly applied policies perform poorly when simulated with more realistic, heterogeneous, myopic, and self-interested agents. In particular, the effects of the physical heterogeneity of the basin and the agents undercut the perceived benefits of policy instruments assessed with simple, single-cell groundwater modeling. This study demonstrates the results of coupling realistic hydrogeology and human behavior models to assess groundwater management policies. The Republican River Basin, which overlies a portion of the Ogallala aquifer in the High Plains of the United States, is used as a case study for this analysis.
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The role of public policies in reducing smoking: the Minnesota SimSmoke tobacco policy model.
Levy, David T; Boyle, Raymond G; Abrams, David B
2012-11-01
Following the landmark lawsuit and settlement with the tobacco industry, Minnesota pursued the implementation of stricter tobacco control policies, including tax increases, mass media campaigns, smokefree air laws, and cessation treatment policies. Modeling is used to examine policy effects on smoking prevalence and smoking-attributable deaths. To estimate the effect of tobacco control policies in Minnesota on smoking prevalence and smoking-attributable deaths using the SimSmoke simulation model. Minnesota data starting in 1993 are applied to SimSmoke, a simulation model used to examine the effect of tobacco control policies over time on smoking initiation and cessation. Upon validating the model against smoking prevalence, SimSmoke is used to distinguish the effect of policies implemented since 1993 on smoking prevalence. Using standard attribution methods, SimSmoke also estimates deaths averted as a result of the policies. SimSmoke predicts smoking prevalence accurately between 1993 and 2011. Since 1993, a relative reduction in smoking rates of 29% by 2011 and of 41% by 2041 can be attributed to tobacco control policies, mainly tax increases, smokefree air laws, media campaigns, and cessation treatment programs. Moreover, 48,000 smoking-attributable deaths will be averted by 2041. Minnesota SimSmoke demonstrates that tobacco control policies, especially taxes, have substantially reduced smoking prevalence and smoking-attributable deaths. Taxes, smokefree air laws, mass media, cessation treatment policies, and youth-access enforcement contributed to the decline in prevalence and deaths averted, with the strongest component being taxes. With stronger policies, for example, increasing cigarette taxes to $4.00 per pack, Minnesota's smoking rate could be reduced by another 13%, and 7200 deaths could be averted by 2041. Copyright © 2012 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.
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Models of policy-making and their relevance for drug research.
Ritter, Alison; Bammer, Gabriele
2010-07-01
Researchers are often frustrated by their inability to influence policy. We describe models of policy-making to provide new insights and a more realistic assessment of research impacts on policy. We describe five prominent models of policy-making and illustrate them with examples from the alcohol and drugs field, before drawing lessons for researchers. Policy-making is a complex and messy process, with different models describing different elements. We start with the incrementalist model, which highlights small amendments to policy, as occurs in school-based drug education. A technical/rational approach then outlines the key steps in a policy process from identification of problems and their causes, through to examination and choice of response options, and subsequent implementation and evaluation. There is a clear role for research, as we illustrate with the introduction of new medications, but this model largely ignores the dominant political aspects of policy-making. Such political aspects include the influence of interest groups, and we describe models about power and pressure groups, as well as advocacy coalitions, and the challenges they pose for researchers. These are illustrated with reference to the alcohol industry, and interest group conflicts in establishing a Medically Supervised Injecting Centre. Finally, we describe the multiple streams framework, which alerts researchers to 'windows of opportunity', and we show how these were effectively exploited in policy for cannabis law reform in Western Australia. Understanding models of policy-making can help researchers maximise the uptake of their work and advance evidence-informed policy.
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Whittaker, Kara A.; McShane, Dan
2013-02-01
A large storm event in southwest Washington State triggered over 2500 landslides and provided an opportunity to assess two slope stability screening tools. The statistical analysis conducted demonstrated that both screening tools are effective at predicting where landslides were likely to take place (Whittaker and McShane, 2012). Here we reply to two discussions of this article related to the development of the slope stability screening tools and the accuracy and scale of the spatial data used. Neither of the discussions address our statistical analysis or results. We provide greater detail on our sampling criteria and also elaborate on the policy and management implications of our findings and how they complement those of a separate investigation of landslides resulting from the same storm. The conclusions made in Whittaker and McShane (2012) stand as originally published unless future analysis indicates otherwise.
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Applications of system dynamics modelling to support health policy.
Atkinson, Jo-An M; Wells, Robert; Page, Andrew; Dominello, Amanda; Haines, Mary; Wilson, Andrew
2015-07-09
The value of systems science modelling methods in the health sector is increasingly being recognised. Of particular promise is the potential of these methods to improve operational aspects of healthcare capacity and delivery, analyse policy options for health system reform and guide investments to address complex public health problems. Because it lends itself to a participatory approach, system dynamics modelling has been a particularly appealing method that aims to align stakeholder understanding of the underlying causes of a problem and achieve consensus for action. The aim of this review is to determine the effectiveness of system dynamics modelling for health policy, and explore the range and nature of its application. A systematic search was conducted to identify articles published up to April 2015 from the PubMed, Web of Knowledge, Embase, ScienceDirect and Google Scholar databases. The grey literature was also searched. Papers eligible for inclusion were those that described applications of system dynamics modelling to support health policy at any level of government. Six papers were identified, comprising eight case studies of the application of system dynamics modelling to support health policy. No analytic studies were found that examined the effectiveness of this type of modelling. Only three examples engaged multidisciplinary stakeholders in collective model building. Stakeholder participation in model building reportedly facilitated development of a common 'mental map' of the health problem, resulting in consensus about optimal policy strategy and garnering support for collaborative action. The paucity of relevant papers indicates that, although the volume of descriptive literature advocating the value of system dynamics modelling is considerable, its practical application to inform health policy making is yet to be routinely applied and rigorously evaluated. Advances in software are allowing the participatory model building approach to be extended to
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Directory of Open Access Journals (Sweden)
Huang Li-Hui
2012-04-01
Full Text Available Abstract Background Neonatal hearing screening (NHS has been routinely offered as a vital component of early childhood care in developed countries, whereas such a screening program is still at the pilot or preliminary stage as regards its nationwide implementation in developing countries. To provide significant evidence for health policy making in China, this study aims to determine the cost-effectiveness of NHS program implementation in case of eight provinces of China. Methods A cost-effectiveness model was conducted and all neonates annually born from 2007 to 2009 in eight provinces of China were simulated in this model. The model parameters were estimated from the established databases in the general hospitals or maternal and child health hospitals of these eight provinces, supplemented from the published literature. The model estimated changes in program implementation costs, disability-adjusted life years (DALYs, average cost-effectiveness ratio (ACER, and incremental cost-effectiveness ratio (ICER for universal screening compared to targeted screening in eight provinces. Results and discussion A multivariate sensitivity analysis was performed to determine uncertainty in health effect estimates and cost-effectiveness ratios using a probabilistic modeling technique. Targeted strategy trended to be cost-effective in Guangxi, Jiangxi, Henan, Guangdong, Zhejiang, Hebei, Shandong, and Beijing from the level of 9%, 9%, 8%, 4%, 3%, 7%, 5%, and 2%, respectively; while universal strategy trended to be cost-effective in those provinces from the level of 70%, 70%, 48%, 10%, 8%, 28%, 15%, 4%, respectively. This study showed although there was a huge disparity in the implementation of the NHS program in the surveyed provinces, both universal strategy and targeted strategy showed cost-effectiveness in those relatively developed provinces, while neither of the screening strategy showed cost-effectiveness in those relatively developing provinces. This
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Prenatal screening and genetics
DEFF Research Database (Denmark)
Alderson, P; Aro, A R; Dragonas, T
2001-01-01
Although the term 'genetic screening' has been used for decades, this paper discusses how, in its most precise meaning, genetic screening has not yet been widely introduced. 'Prenatal screening' is often confused with 'genetic screening'. As we show, these terms have different meanings, and we...... examine definitions of the relevant concepts in order to illustrate this point. The concepts are i) prenatal, ii) genetic screening, iii) screening, scanning and testing, iv) maternal and foetal tests, v) test techniques and vi) genetic conditions. So far, prenatal screening has little connection...... with precisely defined genetics. There are benefits but also disadvantages in overstating current links between them in the term genetic screening. Policy making and professional and public understandings about screening could be clarified if the distinct meanings of prenatal screening and genetic screening were...
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Engels, Melanie A. J.; Heijboer, A. C.; Blankenstein, Marinus A.; van Vugt, John M. G.
2011-01-01
To evaluate the performance of the first-trimester combined test (FCT) in different maternal age groups and to discuss whether adjustments in screening policies should be made. In this retrospective study data (n = 26 274) from a fetal medicine center on FCT (maternal age, fetal NT, free β-human
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International Nuclear Information System (INIS)
Carbiener, W.A.
1983-01-01
The identification of potential sites for a nuclear waste repository through screening procedures in the salt states is a well-established, deliberate process. This screening process has made it possible to carry out detailed studies of many of the most promising potential sites, and general studies of all the sites, in anticipation of the siting guidelines specified in the Nuclear Waste Policy Act. The screening work completed prior to the passage of the Act allowed the Secretary of Energy to identify seven salt sites as potentially acceptable under the provisions of Section 116(a) of the Act. These sites were formally identified by letters from Secretary Hodel to the states of Texas, Utah, Mississippi, and Louisiana on February 2, 1983. The potentially acceptable salt sites were in Deaf Smith and Swisher Counties in Texas; Davis and Lavender Canyons in the Gibson Dome location in Utah; Richton and Cypress Creek Domes in Mississippi; and Vacherie Dome in Louisiana. Further screening will include comparison of each potentially acceptable site against disqualification factors and selection of a preferred site in each of the three geohydrologic settings from those remaining, in accordance with the siting guidelines. These steps will be documented in statutory Environmental Assessments prepared for each site to be nominated for detailed characterization. 9 references
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Energy-economic policy modeling
Sanstad, Alan H.
2018-01-01
Computational models based on economic principles and methods are powerful tools for understanding and analyzing problems in energy and the environment and for designing policies to address them. Among their other features, some current models of this type incorporate information on sustainable energy technologies and can be used to examine their potential role in addressing the problem of global climate change. The underlying principles and the characteristics of the models are summarized, and examples of this class of model and their applications are presented. Modeling epistemology and related issues are discussed, as well as critiques of the models. The paper concludes with remarks on the evolution of the models and possibilities for their continued development.
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Moving Communities Toward Policy Change: APPEAL’s 4-Prong Policy Change Model
Tong, Elisa K.; Lew, Rod
2014-01-01
Policy change is recognized for underlying much of the success of tobacco control. However, there is little evidence and attention on how Asian American and Native Hawaiian and Pacific Islander (AA and NHPI) communities may engage in policy change. Challenges for AA and NHPI communities include the racial/ethnic and geographic diversity, and tobacco data accurately representing the communities. Over the past decade, the Asian Pacific Partners for Empowerment, Advocacy and Leadership (APPEAL) has worked to develop and implement policy change for AA and NHPI communities. This article describes APPEAL’s 4-prong policy change model, in the context of its overall strategic framework for policy change with communities that accounts for varying levels of readiness and leadership capacity, and targets four different levels of policy change (community, mainstream institution, legislative, and corporate). The health promotion implication of this framework for tobacco control policy engagement is for improving understanding of effective pathways to policy change, promoting innovative methods for policy analysis, and translating them into effective implementation and sustainability of policy initiatives. The APPEAL strategic framework can transcend into other communities and health topics that ultimately may contribute to the elimination of health disparities. PMID:23707962
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Simulation models in population breast cancer screening: A systematic review.
Koleva-Kolarova, Rositsa G; Zhan, Zhuozhao; Greuter, Marcel J W; Feenstra, Talitha L; De Bock, Geertruida H
2015-08-01
The aim of this review was to critically evaluate published simulation models for breast cancer screening of the general population and provide a direction for future modeling. A systematic literature search was performed to identify simulation models with more than one application. A framework for qualitative assessment which incorporated model type; input parameters; modeling approach, transparency of input data sources/assumptions, sensitivity analyses and risk of bias; validation, and outcomes was developed. Predicted mortality reduction (MR) and cost-effectiveness (CE) were compared to estimates from meta-analyses of randomized control trials (RCTs) and acceptability thresholds. Seven original simulation models were distinguished, all sharing common input parameters. The modeling approach was based on tumor progression (except one model) with internal and cross validation of the resulting models, but without any external validation. Differences in lead times for invasive or non-invasive tumors, and the option for cancers not to progress were not explicitly modeled. The models tended to overestimate the MR (11-24%) due to screening as compared to optimal RCTs 10% (95% CI - 2-21%) MR. Only recently, potential harms due to regular breast cancer screening were reported. Most scenarios resulted in acceptable cost-effectiveness estimates given current thresholds. The selected models have been repeatedly applied in various settings to inform decision making and the critical analysis revealed high risk of bias in their outcomes. Given the importance of the models, there is a need for externally validated models which use systematical evidence for input data to allow for more critical evaluation of breast cancer screening. Copyright © 2015 Elsevier Ltd. All rights reserved.
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COSMO-RS-based extractant screening for phenol extraction as model system
Burghoff, B.; Goetheer, E.L.V.; Haan, A.B. de
2008-01-01
The focus of this investigation is the development of a fast and reliable extractant screening approach. Phenol extraction is selected as the model process. A quantum chemical conductor-like screening model for real solvents (COSMO-RS) is combined with molecular design considerations. For this
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Modeling of global biomass policies
International Nuclear Information System (INIS)
Gielen, Dolf; Fujino, Junichi; Hashimoto, Seiji; Moriguchi, Yuichi
2003-01-01
This paper discusses the BEAP model and its use for the analysis of biomass policies for CO 2 emission reduction. The model considers competing land use, trade and leakage effects, and competing emission reduction strategies. Two policy scenarios are presented. In case of a 2040 time horizon the results suggest that a combination of afforestation and limited use of biomass for energy and materials constitutes the most attractive set of strategies. In case of a 'continued Kyoto' scenario including afforestation permit trade, the results suggest 5.1 Gt emission reduction based on land use change in 2020, two thirds of the total emission reduction by then. In case of global emission reduction, land use, land use change and forestry (LULUCF) accounts for one quarter of the emission reduction. However these results depend on the modeling time horizon. In case of a broader time horizon, maximized biomass production is more attractive than LULUCF. This result can be interpreted as a warning against a market based trading scheme for LULUCF credits. The model results suggest that the bioenergy market is dominated by transportation fuels and heating, and to a lesser extent feedstocks. Bioelectricity does not gain a significant market share in case competing CO 2 -free electricity options such as CO 2 capture and sequestration and nuclear are considered. To some extent trade in agricultural food products such as beef and cereals will be affected by CO 2 policies
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Modeling of global biomass policies
International Nuclear Information System (INIS)
Gielen, D.; Fujino, Junichi; Hashimoto, Seiji; Moriguchi, Yuichi
2003-01-01
This paper discusses the BEAP model and its use for the analysis of biomass policies for CO 2 emission reduction. The model considers competing land use, trade and leakage effects, and competing emission reduction strategies. Two policy scenarios are presented. In case of a 2040 time horizon the results suggest that a combination of afforestation and limited use of biomass for energy and materials constitutes the most attractive set of strategies. In case of a 'continued Kyoto' scenario including afforestation permit trade, the results suggest 5.1 Gt emission reduction based on land use change in 2020, two thirds of the total emission reduction by then. In case of global emission reduction, land use, land use change and forestry (LULUCF) accounts for one quarter of the emission reduction. However these results depend on the modeling time horizon. In case of a broader time horizon, maximized biomass production is more attractive than LULUCF. This result can be interpreted as a warning against a market based trading scheme for LULUCF credits. The model results suggest that the bioenergy market is dominated by transportation fuels and heating, and to a lesser extent feedstocks. Bioelectricity does not gain a significant market share in case competing CO 2 -free electricity options such as CO 2 capture and sequestration and nuclear are considered. To some extent trade in agricultural food products such as beef and cereals will be affected by CO 2 policies. (Author)
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Validity of information security policy models
Directory of Open Access Journals (Sweden)
Joshua Onome Imoniana
Full Text Available Validity is concerned with establishing evidence for the use of a method to be used with a particular set of population. Thus, when we address the issue of application of security policy models, we are concerned with the implementation of a certain policy, taking into consideration the standards required, through attribution of scores to every item in the research instrument. En today's globalized economic scenarios, the implementation of information security policy, in an information technology environment, is a condition sine qua non for the strategic management process of any organization. Regarding this topic, various studies present evidences that, the responsibility for maintaining a policy rests primarily with the Chief Security Officer. The Chief Security Officer, in doing so, strives to enhance the updating of technologies, in order to meet all-inclusive business continuity planning policies. Therefore, for such policy to be effective, it has to be entirely embraced by the Chief Executive Officer. This study was developed with the purpose of validating specific theoretical models, whose designs were based on literature review, by sampling 10 of the Automobile Industries located in the ABC region of Metropolitan São Paulo City. This sampling was based on the representativeness of such industries, particularly with regards to each one's implementation of information technology in the region. The current study concludes, presenting evidence of the discriminating validity of four key dimensions of the security policy, being such: the Physical Security, the Logical Access Security, the Administrative Security, and the Legal & Environmental Security. On analyzing the Alpha of Crombach structure of these security items, results not only attest that the capacity of those industries to implement security policies is indisputable, but also, the items involved, homogeneously correlate to each other.
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Yu, Jiyang; Silva, Jose; Califano, Andrea
2016-01-15
Functional genomics (FG) screens, using RNAi or CRISPR technology, have become a standard tool for systematic, genome-wide loss-of-function studies for therapeutic target discovery. As in many large-scale assays, however, off-target effects, variable reagents' potency and experimental noise must be accounted for appropriately control for false positives. Indeed, rigorous statistical analysis of high-throughput FG screening data remains challenging, particularly when integrative analyses are used to combine multiple sh/sgRNAs targeting the same gene in the library. We use large RNAi and CRISPR repositories that are publicly available to evaluate a novel meta-analysis approach for FG screens via Bayesian hierarchical modeling, Screening Bayesian Evaluation and Analysis Method (ScreenBEAM). Results from our analysis show that the proposed strategy, which seamlessly combines all available data, robustly outperforms classical algorithms developed for microarray data sets as well as recent approaches designed for next generation sequencing technologies. Remarkably, the ScreenBEAM algorithm works well even when the quality of FG screens is relatively low, which accounts for about 80-95% of the public datasets. R package and source code are available at: https://github.com/jyyu/ScreenBEAM. ac2248@columbia.edu, jose.silva@mssm.edu, yujiyang@gmail.com Supplementary data are available at Bioinformatics online. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.
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Nurses' roles in screening for intimate partner violence: a phenomenological study.
Al-Natour, A; Qandil, A; Gillespie, G L
2016-09-01
To describe Jordanian nurses' roles and practices in screening for intimate partner violence. Intimate partner violence is a recognized global health problem with a prevalence of 37% for the Eastern Mediterranean region. Jordanian nurses screening for intimate partner violence is as low as 10.8%. Nurses have encountered institutional and personal barriers hindering their screening practice. A descriptive phenomenological design was used for this study. A purposive sample of 12 male and female Jordanian nurses working at a university hospital in Jordan participated. Participants were interviewed in 2014 using a semi-structured, face-to-face interview. Steps of Colaizzi's phenomenological method were used to analyse the qualitative data. Four themes were derived from the data: (1) screening practices and roles for suspected IPV cases, (2) advantages for screening and disadvantages for not screening for intimate partner violence, (3) factors hindering screening practice and (4) feelings towards screening and not screening for intimate partner violence. Increasing Jordanian nurses' awareness of the need for intimate partner violence screening in this sample was needed. Professional education and training may facilitate the adoption of intimate partner violence screening practices. A key barrier to intimate partner violence screening is Jordanian nurses' personal beliefs. Overcoming these personal beliefs will necessitate a multi-faceted approach starting with schools of nursing and bridging into healthcare settings. Healthcare professionals including nursing and policy makers at health institutions should enforce screening policies and protocols for all receipt of care at first contact. In addition, an emphasis on modelling culturally congruent approaches to develop the trusting nurse-patient relationships and process for screening patients for intimate partner violence. © 2016 International Council of Nurses.
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Enhancing citizen engagement in cancer screening through deliberative democracy.
Rychetnik, Lucie; Carter, Stacy M; Abelson, Julia; Thornton, Hazel; Barratt, Alexandra; Entwistle, Vikki A; Mackenzie, Geraldine; Salkeld, Glenn; Glasziou, Paul
2013-03-20
Cancer screening is widely practiced and participation is promoted by various social, technical, and commercial drivers, but there are growing concerns about the emerging harms, risks, and costs of cancer screening. Deliberative democracy methods engage citizens in dialogue on substantial and complex problems: especially when evidence and values are important and people need time to understand and consider the relevant issues. Information derived from such deliberations can provide important guidance to cancer screening policies: citizens' values are made explicit, revealing what really matters to people and why. Policy makers can see what informed, rather than uninformed, citizens would decide on the provision of services and information on cancer screening. Caveats can be elicited to guide changes to existing policies and practices. Policies that take account of citizens' opinions through a deliberative democracy process can be considered more legitimate, justifiable, and feasible than those that don't.
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Policy harmonized approach for the EU agricultural sector modelling
Directory of Open Access Journals (Sweden)
G. SALPUTRA
2008-12-01
Full Text Available Policy harmonized (PH approach allows for the quantitative assessment of the impact of various elements of EU CAP direct support schemes, where the production effects of direct payments are accounted through reaction prices formed by producer price and policy price add-ons. Using the AGMEMOD model the impacts of two possible EU agricultural policy scenarios upon beef production have been analysed full decoupling with a switch from historical to regional Single Payment scheme or alternatively with re-distribution of country direct payment envelopes via introduction of EU-wide flat area payment. The PH approach, by systematizing and harmonizing the management and use of policy data, ensures that projected differential policy impacts arising from changes in common EU policies reflect the likely actual differential impact as opposed to differences in how common policies are implemented within analytical models. In the second section of the paper the AGMEMOD models structure is explained. The policy harmonized evaluation method is presented in the third section. Results from an application of the PH approach are presented and discussed in the papers penultimate section, while section 5 concludes.;
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The Dynamics of an HIV/AIDS Model with Screened Disease Carriers
Directory of Open Access Journals (Sweden)
S. D. Hove-Musekwa
2009-01-01
Full Text Available The presence of carriers usually complicates the dynamics and prevention of a disease. They are not recognized as disease cases themselves unless they are screened and they usually spread the infection without them being aware. We argue that this has been one of the major causes of the spread of human immunodeficiency virus (HIV. We propose, in this paper, a model for the heterogeneous transmission of HIV/acquired immunodeficiency syndrome in the presence of disease carriers. The model allows us to assess the role of screening, as an intervention program that can slow the epidemic. A threshold value ψ*, for the screening rate is obtained. It is shown numerically that if 80% or more of the carrier population is screened, the epidemic can be contained. The qualitative analysis is done in terms of the model reproduction number R. The model has two equilibria, the disease free equilibrium and a unique endemic equilibrium. The disease free equilibrium is globally stable of R 1. A detailed discussion of the model reproduction number is given and numerical simulations are done to show the role of some of the important model parameters.
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Modelling climate change under no-policy and policy emissions pathways
International Nuclear Information System (INIS)
Wigley, T.M.L.
2003-01-01
Future emissions under the SRES scenarios are described as examples of no-climate-policy scenarios. The production of policy scenarios is guided by Article 2 of the UN Framework Convention on Climate Change, which requires stabilization of greenhouse-gas concentrations. It is suggested that the choice of stabilization targets should be governed by the need to avoid dangerous interference with the climate system, while the choice of the pathway towards a given target should be determined by some form of cost-benefit analysis. The WRE (Wigley, Richels and Edmonds) concentration profiles are given as examples of stabilization pathways, and an alternative 'overshoot' pathway is introduced. Probabilistic projections (as probability density functions - pdfs) for global-mean temperature under the SRES scenarios are given. The relative importance of different sources of uncertainty is determined by removing individual sources of uncertainty and examining the change in the output temperature pdf. Emissions and climate sensitivity uncertainties dominate, while carbon cycle, aerosol forcing and ocean mixing uncertainties are shown to be small. It is shown that large uncertainties remain even if the emissions are prescribed. Uncertainties in regional climate change are defined by comparing normalized changes (i.e., changes per 1C global-mean warming) across multiple models and using the inter-model standard deviation as an uncertainty metric. Global-mean temperature projections for the policy case are given using the WRE profiles. Different stabilization targets are considered, and the overshoot case for 550ppm stabilization is used to quantify the effects of pathway differences. It is shown that large emissions reductions (from the no-policy to the policy case) will lead to only relatively small reductions in warming over the next 100 years
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Cost Effective Community Based Dementia Screening: A Markov Model Simulation
Directory of Open Access Journals (Sweden)
Erin Saito
2014-01-01
Full Text Available Background. Given the dementia epidemic and the increasing cost of healthcare, there is a need to assess the economic benefit of community based dementia screening programs. Materials and Methods. Markov model simulations were generated using data obtained from a community based dementia screening program over a one-year period. The models simulated yearly costs of caring for patients based on clinical transitions beginning in pre dementia and extending for 10 years. Results. A total of 93 individuals (74 female, 19 male were screened for dementia and 12 meeting clinical criteria for either mild cognitive impairment (n=7 or dementia (n=5 were identified. Assuming early therapeutic intervention beginning during the year of dementia detection, Markov model simulations demonstrated 9.8% reduction in cost of dementia care over a ten-year simulation period, primarily through increased duration in mild stages and reduced time in more costly moderate and severe stages. Discussion. Community based dementia screening can reduce healthcare costs associated with caring for demented individuals through earlier detection and treatment, resulting in proportionately reduced time in more costly advanced stages.
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Levy, David T; Huang, An-Tsun; Havumaki, Joshua S; Meza, Rafael
2016-05-01
Michigan has implemented several of the tobacco control policies recommended by the World Health Organization MPOWER goals. We consider the effect of those policies and additional policies consistent with MPOWER goals on smoking prevalence and smoking-attributable deaths (SADs). The SimSmoke tobacco control policy simulation model is used to examine the effect of past policies and a set of additional policies to meet the MPOWER goals. The model is adapted to Michigan using state population, smoking, and policy data starting in 1993. SADs are estimated using standard attribution methods. Upon validating the model, SimSmoke is used to distinguish the effect of policies implemented since 1993 against a counterfactual with policies kept at their 1993 levels. The model is then used to project the effect of implementing stronger policies beginning in 2014. SimSmoke predicts smoking prevalence accurately between 1993 and 2010. Since 1993, a relative reduction in smoking rates of 22 % by 2013 and of 30 % by 2054 can be attributed to tobacco control policies. Of the 22 % reduction, 44 % is due to taxes, 28 % to smoke-free air laws, 26 % to cessation treatment policies, and 2 % to youth access. Moreover, 234,000 SADs are projected to be averted by 2054. With additional policies consistent with MPOWER goals, the model projects that, by 2054, smoking prevalence can be further reduced by 17 % with 80,000 deaths averted relative to the absence of those policies. Michigan SimSmoke shows that tobacco control policies, including cigarette taxes, smoke-free air laws, and cessation treatment policies, have substantially reduced smoking and SADs. Higher taxes, strong mass media campaigns, and cessation treatment policies would further reduce smoking prevalence and SADs.
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Health care models guiding mental health policy in Kenya 1965 - 1997
Directory of Open Access Journals (Sweden)
Jenkins Rachel
2010-04-01
Full Text Available Abstract Background Mental health policy is needed to set the strategy and direction for the provision of mental health services in a country. Policy formulation does not occur in a vacuum, however, but is influenced by local and international factors in the health sector and other sectors. Methods This study was carried out in 1997 to examine the evolution of mental health policy in Kenya between 1965 and 1997 in the context of changing international concepts of health and development. Qualitative content analysis of policy documents was combined with interviews of key policy makers. Results The study showed that during the period 1965-1997 the generic health policy in Kenya changed from one based on the Medical Model in the 1960s and 1970s to one based on the Primary Health Care Model in the late 1970s and the 1980s and finally to one based on the Market Model of health care in the 1990s. The mental health policy, on the other hand, evolved from one based on the Medical Model in the 1960s to one based on the Primary Health Care Model in the 1990s, but did not embrace the Market Model of health care. This resulted in a situation in the 1990s where the mental health policy was rooted in a different conceptual model from that of the generic health policy under which it was supposed to be implemented. This "Model Muddlement" may have impeded the implementation of the mental health policy in Kenya. Conclusions Integration of the national mental health policy with the general health policy and other sector policies would be appropriate and is now underway.
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The Relevance of Using Mathematical Models in Macroeconomic Policies Theory
Directory of Open Access Journals (Sweden)
Nora Mihail
2006-11-01
Full Text Available The article presents a look of the principal’s mathematical models – starting with Theil, Hansen and Tinbergen work – and their results used to analysis and design macroeconomic policies. In modeling field changes are very fast in theoretical aspects of modeling the many problems of macroeconomic policies and in using in practice the different political models elaboration. The article points out the problems of static and dynamic theory used in macro-policies modeling.
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The Relevance of Using Mathematical Models in Macroeconomic Policies Theory
Directory of Open Access Journals (Sweden)
Nora Mihail
2006-09-01
Full Text Available The article presents a look of the principal’s mathematical models – starting with Theil, Hansen and Tinbergen work – and their results used to analysis and design macroeconomic policies. In modeling field changes are very fast in theoretical aspects of modeling the many problems of macroeconomic policies and in using in practice the different political models elaboration. The article points out the problems of static and dynamic theory used in macro-policies modeling.
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THE SHEFFIELD ALCOHOL POLICY MODEL - A MATHEMATICAL DESCRIPTION.
Brennan, Alan; Meier, Petra; Purshouse, Robin; Rafia, Rachid; Meng, Yang; Hill-Macmanus, Daniel; Angus, Colin; Holmes, John
2014-09-30
This methodology paper sets out a mathematical description of the Sheffield Alcohol Policy Model version 2.0, a model to evaluate public health strategies for alcohol harm reduction in the UK. Policies that can be appraised include a minimum price per unit of alcohol, restrictions on price discounting, and broader public health measures. The model estimates the impact on consumers, health services, crime, employers, retailers and government tax revenues. The synthesis of public and commercial data sources to inform the model structure is described. A detailed algebraic description of the model is provided. This involves quantifying baseline levels of alcohol purchasing and consumption by age and gender subgroups, estimating the impact of policies on consumption, for example, using evidence on price elasticities of demand for alcohol, quantification of risk functions relating alcohol consumption to harms including 47 health conditions, crimes, absenteeism and unemployment, and finally monetary valuation of the consequences. The results framework, shown for a minimum price per unit of alcohol, has been used to provide policy appraisals for the UK government policy-makers. In discussion and online appendix, we explore issues around valuation and scope, limitations of evidence/data, how the framework can be adapted to other countries and decisions, and ongoing plans for further development. © 2014 The Authors. Health Economics published by John Wiley & Sons Ltd. © 2014 The Authors. Health Economics published by John Wiley & Sons Ltd.
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In Vivo RNAi-Based Screens: Studies in Model Organisms
Directory of Open Access Journals (Sweden)
Miki Yamamoto-Hino
2013-11-01
Full Text Available RNA interference (RNAi is a technique widely used for gene silencing in organisms and cultured cells, and depends on sequence homology between double-stranded RNA (dsRNA and target mRNA molecules. Numerous cell-based genome-wide screens have successfully identified novel genes involved in various biological processes, including signal transduction, cell viability/death, and cell morphology. However, cell-based screens cannot address cellular processes such as development, behavior, and immunity. Drosophila and Caenorhabditis elegans are two model organisms whose whole bodies and individual body parts have been subjected to RNAi-based genome-wide screening. Moreover, Drosophila RNAi allows the manipulation of gene function in a spatiotemporal manner when it is implemented using the Gal4/UAS system. Using this inducible RNAi technique, various large-scale screens have been performed in Drosophila, demonstrating that the method is straightforward and valuable. However, accumulated results reveal that the results of RNAi-based screens have relatively high levels of error, such as false positives and negatives. Here, we review in vivo RNAi screens in Drosophila and the methods that could be used to remove ambiguity from screening results.
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Modelling Options for Policy Impact Analysis on African Dairy Farms
Directory of Open Access Journals (Sweden)
Oghaiki Asaah NDAMBI
2008-01-01
Full Text Available Studies on the priorities for agricultural research in Eastern and CentralAfrica concluded that milk is the most important commodity for research anddevelopment in the region, based on its potential contribution to the agriculturalGDP. It has been presumed that, the right policies, marketing systems and technicalsupport must be sought for dairy development in Africa. In order to determine theright development pattern, appropriate analytical tools must be applied. The TIPICAL(Technology Impact Policy Impact model was used to analyse the impact ofdifferent policies on two typical dairy farming systems in Uganda, which accountfor more than 70% of milk produced in the country. Seven influential policy areaswere also identified: provision of veterinary services, consumption promotion,marketing promotion, input provision, credit access improvement, milk qualityimprovement and genetic improvement. In general, the policy impacts are very littleon farms with local cows but can be magnified up to threefold, if the farms havegraded cows. Policies which improve farmers’ accessibility to markets have thegreatest impacts. The results obtained from this model were compared to thoseusing the EXTRAPOLATE model. This comparison shows that both models couldcomplement each other in analysing policy impacts on African dairy farms.However, differences in results from the models indicate that more focus should bemade on farmers’ willingness to adopt new technology.
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Printer model for dot-on-dot halftone screens
Balasubramanian, Raja
1995-04-01
A printer model is described for dot-on-dot halftone screens. For a given input CMYK signal, the model predicts the resulting spectral reflectance of the printed patch. The model is derived in two steps. First, the C, M, Y, K dot growth functions are determined which relate the input digital value to the actual dot area coverages of the colorants. Next, the reflectance of a patch is predicted as a weighted combination of the reflectances of the four solid C, M, Y, K patches and their various overlays. This approach is analogous to the Neugebauer model, with the random mixing equations being replaced by dot-on-dot mixing equations. A Yule-Neilsen correction factor is incorporated to account for light scattering within the paper. The dot area functions and Yule-Neilsen parameter are chosen to optimize the fit to a set of training data. The model is also extended to a cellular framework, requiring additional measurements. The model is tested with a four color xerographic printer employing a line-on-line halftone screen. CIE L*a*b* errors are obtained between measurements and model predictions. The Yule-Neilsen factor significantly decreases the model error. Accuracy is also increased with the use of a cellular framework.
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Suomi NPP VIIRS solar diffuser screen transmittance model and its applications.
Lei, Ning; Xiong, Xiaoxiong; Mcintire, Jeff
2017-11-01
The visible infrared imaging radiometer suite on the Suomi National Polar-orbiting Partnership satellite calibrates its reflective solar bands through observations of a sunlit solar diffuser (SD) panel. Sunlight passes through a perforated plate, referred to as the SD screen, before reaching the SD. It is critical to know whether the SD screen transmittance measured prelaunch is accurate. Several factors such as misalignments of the SD panel and the measurement apparatus could lead to errors in the measured transmittance and thus adversely impact on-orbit calibration quality through the SD. We develop a mathematical model to describe the transmittance as a function of the angles that incident light makes with the SD screen, and apply the model to fit the prelaunch measured transmittance. The results reveal that the model does not reproduce the measured transmittance unless the size of the apertures in the SD screen is quite different from the design value. We attribute the difference to the orientation alignment errors for the SD panel and the measurement apparatus. We model the alignment errors and apply our transmittance model to fit the prelaunch transmittance to retrieve the "true" transmittance. To use this model correctly, we also examine the finite source size effect on the transmittance. Furthermore, we compare the product of the retrieved "true" transmittance and the prelaunch SD bidirectional reflectance distribution function (BRDF) value to the value derived from on-orbit data to determine whether the prelaunch SD BRDF value is relatively accurate. The model is significant in that it can evaluate whether the SD screen transmittance measured prelaunch is accurate and help retrieve the true transmittance from the transmittance with measurement errors, consequently resulting in a more accurate sensor data product by the same amount.
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THREE MODELS OF NATIONAL CRIMINAL POLICY IN THE CONTEXT OF GLOBALIZATION
Directory of Open Access Journals (Sweden)
Ivan Kleymenov
2017-01-01
Full Text Available The author identifies three models of national criminal policy: the sovereign, reformist and experimental. The main criteria of such differentiation are the exposure to global influence, the criminological soundness and stability of criminal policy. Identification of the model of criminal policy in a particular state is a complex task that requires independent research.The subject. The article is devoted to modeling of the national criminal policy in modern conditions of globalization. The article discusses various models of criminal policy in the conditions of globalization.The purpose of the author is to describe the basic models of national criminal policy in modern conditions of globalization.The methodology. The author uses the method of analysis and synthesis, formal legal method as well as sociological methods (survey.The results, scope of application. The author identifies three models of national criminal policy: the sovereign, reformist and experimental. The main criteria of such differentiation are the exposure to global influence, the criminological soundness and stability of criminal policy. The sovereign model is based on doctrine of weak state and a strong combat criminal activity. It is distinguished by the pursuit of the realization of the equality of all before the law, criminal strategic and political planning system with a clear definition of goals and objectives; criminological security. The reform of criminal policy is characterized byuncertainty goals and objectives, utopianism and pretentiousness, dependence on standards of the international organization, the lower prestige of criminology, reduction of social programs, lobbying of group interests, permanent amendments to the criminal and criminal procedure legislation. Experimental model of criminal policy is connected with approbation of such technologies of management of society that are criminal and contrary to human experience in fighting crime.Conclusions. Criminal
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Production functions for climate policy modeling. An empirical analysis
International Nuclear Information System (INIS)
Van der Werf, Edwin
2008-01-01
Quantitative models for climate policy modeling differ in the production structure used and in the sizes of the elasticities of substitution. The empirical foundation for both is generally lacking. This paper estimates the parameters of 2-level CES production functions with capital, labour and energy as inputs, and is the first to systematically compare all nesting structures. Using industry-level data from 12 OECD countries, we find that the nesting structure where capital and labour are combined first, fits the data best, but for most countries and industries we cannot reject that all three inputs can be put into one single nest. These two nesting structures are used by most climate models. However, while several climate policy models use a Cobb-Douglas function for (part of the) production function, we reject elasticities equal to one, in favour of considerably smaller values. Finally we find evidence for factor-specific technological change. With lower elasticities and with factor-specific technological change, some climate policy models may find a bigger effect of endogenous technological change on mitigating the costs of climate policy. (author)
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Katki, Hormuzd A; Kovalchik, Stephanie A; Petito, Lucia C; Cheung, Li C; Jacobs, Eric; Jemal, Ahmedin; Berg, Christine D; Chaturvedi, Anil K
2018-05-15
Lung cancer screening guidelines recommend using individualized risk models to refer ever-smokers for screening. However, different models select different screening populations. The performance of each model in selecting ever-smokers for screening is unknown. To compare the U.S. screening populations selected by 9 lung cancer risk models (the Bach model; the Spitz model; the Liverpool Lung Project [LLP] model; the LLP Incidence Risk Model [LLPi]; the Hoggart model; the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial Model 2012 [PLCOM2012]; the Pittsburgh Predictor; the Lung Cancer Risk Assessment Tool [LCRAT]; and the Lung Cancer Death Risk Assessment Tool [LCDRAT]) and to examine their predictive performance in 2 cohorts. Population-based prospective studies. United States. Models selected U.S. screening populations by using data from the National Health Interview Survey from 2010 to 2012. Model performance was evaluated using data from 337 388 ever-smokers in the National Institutes of Health-AARP Diet and Health Study and 72 338 ever-smokers in the CPS-II (Cancer Prevention Study II) Nutrition Survey cohort. Model calibration (ratio of model-predicted to observed cases [expected-observed ratio]) and discrimination (area under the curve [AUC]). At a 5-year risk threshold of 2.0%, the models chose U.S. screening populations ranging from 7.6 million to 26 million ever-smokers. These disagreements occurred because, in both validation cohorts, 4 models (the Bach model, PLCOM2012, LCRAT, and LCDRAT) were well-calibrated (expected-observed ratio range, 0.92 to 1.12) and had higher AUCs (range, 0.75 to 0.79) than 5 models that generally overestimated risk (expected-observed ratio range, 0.83 to 3.69) and had lower AUCs (range, 0.62 to 0.75). The 4 best-performing models also had the highest sensitivity at a fixed specificity (and vice versa) and similar discrimination at a fixed risk threshold. These models showed better agreement on size of the
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A review of Agent Based Modeling for agricultural policy evaluation
Kremmydas, Dimitris; Athanasiadis, I.N.; Rozakis, Stelios
2018-01-01
Farm level scale policy analysis is receiving increased attention due to a changing agricultural policy orientation. Agent based models (ABM) are farm level models that have appeared in the end of 1990's, having several differences from traditional farm level models, like the consideration of
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Global climate change policies. An analysis of CDM policies with an adapted GTAP model
International Nuclear Information System (INIS)
Wang, Shunli
2004-01-01
In the context of the relationships between spatial-economic interaction and global warming just discussed, this study aims to analyze the Clean Development Mechanisms (CDM) policies from an economic point of view. The research question of this study is formulated as follows: What will be the impacts of clirnate change policies, in particular CDM policies, on the economic performance of (groups of) countries in our global economic system, taking spatial interaction and general equilibrium effects into account? The purpose of addressing the issue of economic performance for (groups of) countries in the economic system is not just to identify winners and losers from international treaties. Rather, winning or losing may even determine the implementation and willingness of individual countries to participate in international environmental treaties, as illustrated by the recent withdrawal of the US from the Kyoto Protocol. By analyzing the economic impacts of an international environmental treaty for individual (groups of) countries, the framework that will be used to analyze this research question may be useful to determine the attractiveness of some global environmental policies, both for the world as a whole and for individual (groups of) countries. The research question will be answered by dividing it into six subquestions: (1) What is the position of CDM policies in the broad context of climate policy regimes?; (2) How should the relationship between human behavior and the physical environment be ideally modeled from an economic perspective? (3) How should the spatial dimension be incorporated in this framework of interaction between the economic and ecological system?; (4) How can climate change issues be incorporated in general equilibrium models in general, and in GTAP-E (extension of the Global Trade Analysis Project) in particular?; (5) How can CDM policies be implemented in the GTAP-E model?; and (6) What are the impacts of these climate change policies on
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An evaluation model for low carbon island policy: The case of Taiwan's green transportation policy
International Nuclear Information System (INIS)
Trappey, Amy J.C.; Trappey, Charles; Hsiao, C.T.; Ou, Jerry J.R.; Li, S.J.; Chen, Kevin W.P.
2012-01-01
Conserving energy and reducing carbon emissions have become the common responsibility of the international community. During the year 2010, the Taiwan government planned a four-year project budgeted at 300 million US dollars, called “The Penghu Low Carbon Island Development Project.” The policy objective is to use Penghu Island (population 85,000) as a test platform to evaluate new ways to conserve energy and reduce carbon emissions before attempting to replicate the policies on Taiwan Island. For Taiwan, a zero carbon island green transportation policy will regulate the total number of electric scooters, the total number of gasoline motorcycles, influence government subsidy incentives, and create the need for new motorcycle license issuing and control. These factors interact with each other to form a complex and dynamic system that impacts policy as well as the current way of life. In this study, a system dynamics approach is designed to construct a model for evaluating the green transportation policy on Penghu Island. Simulations are conducted to model green transportation system behavior and related policy effects in a smaller, controlled environment before creating policies for Taiwan Island that will impact the lives of over 23 million people. - Highlights: ► Provides an overview of Taiwan's Penghu Low Carbon Island Development Project. ► Develops a systems dynamics approach for green transportation policy assessment. ► Provides causal analysis of social, economic, and environmental factors. ► Demonstrates that the proposed policy cannot meet the CO 2 reduction goals. ► Alternative policies can be evaluated using the proposed approach.
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Modeling fiber motion in a pulp pressure screen: the effect of slot shape
International Nuclear Information System (INIS)
Dong, S.; Salcudean, M.; Gartshore, I.
2003-01-01
A pressure screen is a piece of equipment in the pulp and paper industry used either to remove contaminants from the pulp suspension or to separate fibers having different properties. Contaminants such as fiber bundles, bark and plastic specks are introduced when fibers are separated from the wood by mechanical or chemical pulping processes. Contaminants significantly affect the strength and smoothness of the paper and must be removed before the final paper is produced. The screen plate is a critical part of the pressure screen and its design is the key to screen performance. This paper uses a new and comprehensive CFD simulation tool to examine the flow and fiber behavior in a single slot screen having any reasonable slot shape. -This simulation tool includes three coupled models: first, the flow model solves the Reynolds Averaged Navier-Stokes (RANS) equation using the standard k - ε turbulence model to predict the flow field in the equipment. Second, a three-dimensional flexible fiber model is used to track the fiber trajectory in the screen. Third, a very general wall model is used to deal with the case when a fiber touches the equipment wall. The simulated results show that the slot shape has a critical influence on fiber behavior and screen performance. Three general slot shapes were investigated: the smooth slot, the step-step contour slot and slope-slope contour slot. Of these the slope-slope contour slot provides the best passage for the fibers with a length of 1mm and 3mm. (author)
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Uncertainty and endogenous technical change in climate policy models
International Nuclear Information System (INIS)
Baker, Erin; Shittu, Ekundayo
2008-01-01
Until recently endogenous technical change and uncertainty have been modeled separately in climate policy models. In this paper, we review the emerging literature that considers both these elements together. Taken as a whole the literature indicates that explicitly including uncertainty has important quantitative and qualitative impacts on optimal climate change technology policy. (author)
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S, Abrahams-Gessel; Denman, C A; Ta, Gaziano; Ns, Levitt; T, Puoane
The integration of community health workers (CHWs) into primary and secondary prevention functions in health programs and services delivery in Mexico and South Africa has been demonstrated to be effective. Task-sharing related to adherence and treatment, from nurses to CHWs, has also been effectively demonstrated in these areas. HIV/AIDS and TB programs in South Africa have seen similar successes in task-sharing with CHWs in the areas of screening for risk and adherence to treatment. In the area of non-communicable diseases (NCDs), there is a policy commitment to integrating CHWs into primary health care programs at public health facilities in both Mexico and South Africa in the areas of reproductive health and infant health. Yet current programs utilizing CHWs are not integrated into existing primary health care services in a comprehensive manner for primary and secondary prevention of NCDs. In a recently completed study, CHWs were trained to perform the basic diagnostic function of primary screening to assess the risk of suffering a CVD-related event in the community using a non-laboratory risk assessment tool and referring persons at moderate to high risk to local government clinics, for further assessment and management by a nurse or physician. In this paper we compare the experience with this CVD screening study to successful programs in vaccination, reproductive health, HIV/AIDS, and TB specifically to identify the barriers we identified as limitations to replicating these programs in the area of CVD diagnosis and management. We review barriers impacting the effective translation of policy into practice, including scale up issues; training and certification issues; integrating CHW to existing primary care teams and health system; funding and resource gaps. Finally, we suggest policy recommendations to replicate the demonstrated success of programs utilizing task-sharing with CHWs in infectious diseases and reproductive health, to integrated programs in NCD.
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Maryland's Model Policy to Address Bullying, Harassment, or Intimidation
Maryland State Department of Education, 2016
2016-01-01
In accordance with the provisions of Section 7-424.1 of the Education Article of the Annotated Code of Maryland, the Maryland State Board of Education has developed and adopted a Model Policy to address bullying, harassment, or intimidation. This report presents the Model Policy, which is organized into the following eight points: (1) Prohibition…
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Tian, Yuzhen; Guo, Jin; Wang, Rui; Wang, Tingfeng
2011-09-12
In order to research the statistical properties of Gaussian beam propagation through an arbitrary thickness random phase screen for adaptive optics and laser communication application in the laboratory, we establish mathematic models of statistical quantities, which are based on the Rytov method and the thin phase screen model, involved in the propagation process. And the analytic results are developed for an arbitrary thickness phase screen based on the Kolmogorov power spectrum. The comparison between the arbitrary thickness phase screen and the thin phase screen shows that it is more suitable for our results to describe the generalized case, especially the scintillation index.
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Experiences with a dialogue process between policy makers and global modellers
International Nuclear Information System (INIS)
Van Daalen, C.E.; Thissen, W.A.H.; Berk, M.M.
1998-01-01
Between 1995 and 1997, a series of five workshops, henceforth called the Delft process, took place with the aim to explore and enhance use of the IMAGE 2 model to support international climate negotiations. The IMAGE 2 model is a multi-disciplinary, integrated model designed to simulate the dynamics of the global society-biosphere-climate system. The workshops facilitated a dialogue between policy makers and scientists involved in the development and applications of the IMAGE 2 model. In this way, policy makers would benefit from the policy makers on how to improve the policy relevance of the IMAGE 2 model. The evaluation at the end of the workshop series showed that participants have used information from the workshop at international negotiation conferences and in preparation of policy documents. The process shows that creating a forum for direct science-policy interactions can be very useful and productive, and has confirmed the importance of creating an open and constructive atmosphere between policy makers, and between policy makers and analysts, to enhance utilisation of scientific knowledge. The authors' analysis also suggests that many factors have to be 'in the right position at the right time and place' to achieve such a success, and that it is difficult to prevent the occurrence of biases in processes like this. 33 refs
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Directory of Open Access Journals (Sweden)
Howard Kirsten
2010-11-01
Full Text Available Abstract Background The National Cervical Screening Program in Australia currently recommends that sexually active women between the ages of 18-70 years attend routine screening every 2 years. The publically funded National HPV Vaccination Program commenced in 2007, with catch-up in females aged 12-26 years conducted until 2009; and this may prompt consideration of whether the screening interval and other aspects of the organized screening program could be reviewed. The aim of the current evaluation was to assess the epidemiologic outcomes and cost implications of changing the recommended screening interval in Australia to 3 years. Methods We used a modelling approach to evaluate the effects of moving to a 3-yearly recommended screening interval. We used data from the Victorian Cervical Cytology Registry over the period 1997-2007 to model compliance with routine screening under current practice, and registry data from other countries with 3-yearly recommendations to inform assumptions about future screening behaviour under two alternative systems for screening organisation - retention of a reminder-based system (as in New Zealand, or a move to a call-and-recall system (as in England. Results A 3-yearly recommendation is predicted to be of similar effectiveness to the current 2-yearly recommendation, resulting in no substantial change to the total number of incident cervical cancer cases or cancer deaths, or to the estimated 0.68% average cumulative lifetime risk of cervical cancer in unvaccinated Australian women. However, a 3-yearly screening policy would be associated with decreases in the annual number of colposcopy and biopsy procedures performed (by 4-10% and decreases in the number of treatments for pre-invasive lesions (by 2-4%. The magnitude of the decrease in the number of diagnostic procedures and treatments would depend on the method of screening organization, with call-and-recall screening associated with the highest reductions. The
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Evaluating business models for microgrids: Interactions of technology and policy
International Nuclear Information System (INIS)
Hanna, Ryan; Ghonima, Mohamed; Kleissl, Jan; Tynan, George; Victor, David G.
2017-01-01
Policy makers are increasingly focused on strategies to decentralize the electricity grid. We analyze the business model for one mode of decentralization—microgrids—and quantify the economics for self-supply of electricity and thermal energy and explicitly resolve technological as well as policy variables. We offer a tool, based on the Distributed Energy Resources Customer Adoption Model (DER-CAM) modeling framework, that determines the cost-minimal capacity and operation of distributed energy resources in a microgrid, and apply it in southern California to three “iconic” microgrid types which represent typical commercial adopters: a large commercial building, critical infrastructure, and campus. We find that optimal investment leads to some deployment of renewables but that natural gas technologies underpin the most robust business cases—due in part to relatively cheap gas and high electricity rates. This finding contrasts sharply with most policy advocacy, which has focused on the potentials for decentralization of the grid to encourage deployment of renewables. Decentralization could radically reduce customer energy costs, but without the right policy framework it could create large numbers of small decentralized sources of gas-based carbon emissions that will be difficult to control if policy makers want to achieve deep cuts in greenhouse gas emissions. - Highlights: • We offer a modeling tool to study technology and policy variables for microgrids. • We construct comprehensive load profiles for three likely adopters of microgrids. • Investment in natural gas generators is key to enabling business models. • Solar PV and storage are optimal but as supplements to gas generation. • Business models are highly robust to sensitivity in technology and policy variables.
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Dynamic and adaptive policy models for coalition operations
Verma, Dinesh; Calo, Seraphin; Chakraborty, Supriyo; Bertino, Elisa; Williams, Chris; Tucker, Jeremy; Rivera, Brian; de Mel, Geeth R.
2017-05-01
It is envisioned that the success of future military operations depends on the better integration, organizationally and operationally, among allies, coalition members, inter-agency partners, and so forth. However, this leads to a challenging and complex environment where the heterogeneity and dynamism in the operating environment intertwines with the evolving situational factors that affect the decision-making life cycle of the war fighter. Therefore, the users in such environments need secure, accessible, and resilient information infrastructures where policy-based mechanisms adopt the behaviours of the systems to meet end user goals. By specifying and enforcing a policy based model and framework for operations and security which accommodates heterogeneous coalitions, high levels of agility can be enabled to allow rapid assembly and restructuring of system and information resources. However, current prevalent policy models (e.g., rule based event-condition-action model and its variants) are not sufficient to deal with the highly dynamic and plausibly non-deterministic nature of these environments. Therefore, to address the above challenges, in this paper, we present a new approach for policies which enables managed systems to take more autonomic decisions regarding their operations.
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Hopf bifurcation and chaos in macroeconomic models with policy lag
International Nuclear Information System (INIS)
Liao Xiaofeng; Li Chuandong; Zhou Shangbo
2005-01-01
In this paper, we consider the macroeconomic models with policy lag, and study how lags in policy response affect the macroeconomic stability. The local stability of the nonzero equilibrium of this equation is investigated by analyzing the corresponding transcendental characteristic equation of its linearized equation. Some general stability criteria involving the policy lag and the system parameter are derived. By choosing the policy lag as a bifurcation parameter, the model is found to undergo a sequence of Hopf bifurcation. The direction and stability of the bifurcating periodic solutions are determined by using the normal form theory and the center manifold theorem. Moreover, we show that the government can stabilize the intrinsically unstable economy if the policy lag is sufficiently short, but the system become locally unstable when the policy lag is too long. We also find the chaotic behavior in some range of the policy lag
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Brennan, Alan; Meier, Petra; Purshouse, Robin; Rafia, Rachid; Meng, Yang; Hill-Macmanus, Daniel
This paper sets out the development of a methodological framework for detailed evaluation of public health strategies for alcohol harm reduction to meet UK policy-makers needs. Alcohol is known to cause substantial harms, and controlling its affordability and availability are effective policy options. Analysis and synthesis of a variety of public and commercial data sources is needed to evaluate impact on consumers, health services, crime, employers and industry, so a sound evaluation of impact is important. We discuss the iterative process to engage with stakeholders, identify evidence/data and develop analytic approaches and produce a final model structure. We set out a series of steps in modelling impact including: classification and definition of population subgroups of interest, identification and definition of harms and outcomes for inclusion, classification of modifiable components of risk and their baseline values, specification of the baseline position on policy variables especially prices, estimating effects of changing policy variables on risk factors including price elasticities, quantifying risk functions relating risk factors to harms including 47 health conditions, crimes, absenteeism and unemployment, and monetary valuation. The most difficult model structuring decisions are described, as well as the final results framework used to provide decision support to national level policymakers in the UK. In the discussion we explore issues around the relationship between modelling and policy debates, valuation and scope, limitations of evidence/data, how the framework can be adapted to other countries and decisions. We reflect on the approach taken and outline ongoing plans for further development.
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Pharmaceutical expenditure forecast model to support health policy decision making
R?muzat, C?cile; Urbinati, Duccio; Kornfeld, ?sa; Vataire, Anne-Lise; Cetinsoy, Laurent; Aball?a, Samuel; Mzoughi, Olfa; Toumi, Mondher
2014-01-01
Background and objective: With constant incentives for healthcare payers to contain their pharmaceutical budgets, modelling policy decision impact became critical. The objective of this project was to test the impact of various policy decisions on pharmaceutical budget (developed for the European Commission for the project ‘European Union (EU) Pharmaceutical expenditure forecast’ – http://ec.europa.eu/health/healthcare/key_documents/index_en.htm).Methods: A model was built to assess policy sc...
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Systems Thinking and Simulation Modeling to Inform Childhood Obesity Policy and Practice.
Powell, Kenneth E; Kibbe, Debra L; Ferencik, Rachel; Soderquist, Chris; Phillips, Mary Ann; Vall, Emily Anne; Minyard, Karen J
In 2007, 31.7% of Georgia adolescents in grades 9-12 were overweight or obese. Understanding the impact of policies and interventions on obesity prevalence among young people can help determine statewide public health and policy strategies. This article describes a systems model, originally launched in 2008 and updated in 2014, that simulates the impact of policy interventions on the prevalence of childhood obesity in Georgia through 2034. In 2008, using information from peer-reviewed reports and quantitative estimates by experts in childhood obesity, physical activity, nutrition, and health economics and policy, a group of legislators, legislative staff members, and experts trained in systems thinking and system dynamics modeling constructed a model simulating the impact of policy interventions on the prevalence of childhood obesity in Georgia through 2034. Use of the 2008 model contributed to passage of a bill requiring annual fitness testing of schoolchildren and stricter enforcement of physical education requirements. We updated the model in 2014. With no policy change, the updated model projects that the prevalence of obesity among children and adolescents aged ≤18 in Georgia would hold at 18% from 2014 through 2034. Mandating daily school physical education (which would reduce prevalence to 12%) and integrating moderate to vigorous physical activity into elementary classrooms (which would reduce prevalence to 10%) would have the largest projected impact. Enacting all policies simultaneously would lower the prevalence of childhood obesity from 18% to 3%. Systems thinking, especially with simulation models, facilitates understanding of complex health policy problems. Using a simulation model to educate legislators, educators, and health experts about the policies that have the greatest short- and long-term impact should encourage strategic investment in low-cost, high-return policies.
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48 CFR 2919.201 - General policy.
2010-10-01
... Business Utilization, prior to being advertised. The Acquisition Screening and Review Form DL-1-2004 shall... BUSINESS AND SMALL DISADVANTAGED BUSINESS CONCERNS Policies 2919.201 General policy. (a) It is the policy of the Department of Labor to provide maximum practicable opportunities to small businesses in...
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CHAM: a fast algorithm of modelling non-linear matter power spectrum in the sCreened HAlo Model
Hu, Bin; Liu, Xue-Wen; Cai, Rong-Gen
2018-05-01
We present a fast numerical screened halo model algorithm (CHAM, which stands for the sCreened HAlo Model) for modelling non-linear power spectrum for the alternative models to Λ cold dark matter. This method has three obvious advantages. First of all, it is not being restricted to a specific dark energy/modified gravity model. In principle, all of the screened scalar-tensor theories can be applied. Secondly, the least assumptions are made in the calculation. Hence, the physical picture is very easily understandable. Thirdly, it is very predictable and does not rely on the calibration from N-body simulation. As an example, we show the case of the Hu-Sawicki f(R) gravity. In this case, the typical CPU time with the current parallel PYTHON script (eight threads) is roughly within 10 min. The resulting spectra are in a good agreement with N-body data within a few percentage accuracy up to k ˜ 1 h Mpc-1.
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The French nuclear policy. A model for security policy in North-East Asia
International Nuclear Information System (INIS)
Choe, K.
1998-01-01
Between the end of the second world war and the collapse of the Berlin wall, the French diplomacy was based on the nuclear policy in a solid and coherent way. This nuclear policy was an 'incarnation' of the national security conception, allowing France to recover its political, military and economical rank on the international scene. The most important characteristic of the French nuclear policy concerns the commercialization of the nuclear energy which aims to ensuring the national security through the building up of a financial, technological and political 'reserve'. In front of the domination of the USA and USSR during the cold war era, NE Asia had a similar geostrategic configuration as Western Europe. It concerns in particular the massive application of nuclear energy for both military and industrial purposes. The bases of the security policy in this region refers to the real use of the nuclear weapon by the USA against Japan in 1945. The French nuclear policy may be considered as a model for the building of the security policy of NE Asia, in particular through the commercialization of the nuclear technology between the countries in concern. This nuclear approach would allow the countries of these region to change their present day national defense policy into an economical and military cooperation. (J.S.)
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JERM model of care: an in-principle model for dental health policy.
Lam, Raymond; Kruger, Estie; Tennant, Marc
2014-01-01
Oral diseases are the most prevalent conditions in the community. Their economic burden is high and their impact on quality of life is profound. There is an increasing body of evidence indicating that oral diseases have wider implications beyond the confines of the mouth. The importance of oral health has not been unnoticed by the government. The Commonwealth (Federal) government under the Howard-led Coalition in 2004 had broken tradition by placing dentistry in its universal health insurance scheme, Medicare. Known as the Chronic Disease Dental Scheme (CDDS), the program aimed to manage patients with chronic conditions as part of the Enhanced Primary Care initiative. This scheme was a landmark policy for several reasons. Besides being the first major dental policy under Medicare, the program proved to be the most expensive and controversial. Unfortunately, cost containment and problems with service provision led to its cessation in 2012 by the Gillard Labor Government. Despite being seen as a failure, the CDDS provided a unique opportunity to assess national policy in practice. By analysing the policy-relevant effects of the CDDS, important lessons can be learnt for policy development. This paper discusses these lessons and has formulated a set of principles recommended for effective oral health policy. The JERM model represents the principles of a justified, economical and research-based model of care.
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Kretzschmar, Mirjam; Satterwhite, Catherine; Leichliter, Jami; Berman, Stuart
2012-05-01
Model impact of increasing screening and partner notification (PN) on chlamydia positivity. We used a stochastic simulation model describing pair formation and dissolution in an age-structured heterosexual population. The model accounts for steady, casual, and concurrent partnerships and a highly sexually active core group. The model used existing sexual behavior data from the United States and was validated using chlamydia positivity data from Region X (Alaska, Idaho, Oregon, Washington). A screening program with a coverage rate of 20% was implemented among women aged 15 to 24 years. After 10 years, we increased screening coverage to 35%, 50%, and 65% and partner treatment rates from 20% to 40% and 55%. Finally, we included male screening (aged 15-24, screening coverage: 20% and 35%, partner treatment: 25% and 40%). We analyzed the effects on chlamydia positivity in women and the frequency of reinfection 6 months after treatment. The model described the decline in positivity observed from 1988 to 1997 in Region X, given screening coverage of 20% and a 25% partner treatment rate. Increasing screening coverage from 35% to 65% resulted in incremental decreases in positivity as did increasing the PN rate; a 23% reduction in positivity was achieved by either increasing screening by 3-fold or PN by 2-fold. Adding male screening to the program had less impact than increasing screening coverage or PN among women. Increased PN and treatment reduced reinfection rates considerably. Increasing efforts in PN may contribute at least as much to control of chlamydia infection as increasing screening coverage rates.
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A Model for determination of screening levels for radioactive elements in soil
International Nuclear Information System (INIS)
Peres, Ana C.; Hiromoto, Goro
2008-01-01
Full text: At the present, decision about clean-up of Brazilian sites contaminated with radioactive isotopes is addressed on a case-by-case basis, since there is no general guidance or recommendation to support actions in early phases of the problem identification. For chemicals, CETESB - the governmental organization responsible for preventing and controlling environmental pollution in Sao Paulo State - established quality reference values for prevention and intervention, as the first step to implement a remediation policy based on human health risk assessment. The aim of this study is to develop a methodology for the establishment of target values for radioactive soil contamination, as far as possible consistent and compatible with the approach adopted by CETESB for sites contaminated with chemicals. The following steps have been addressed in this study: conceptual scenario and model development; codification of the equations in an electronic spreadsheet; selection of proper input values; derivation of the intervention levels for selected radionuclides using Monte Carlo methods. The mathematical model developed was mainly based on the equations used by the U.S. Environmental Protection Agency and by the National Council on Radiation Protection and Measurements for soil screening purposes. Results are presented for selected natural and man-made radioactive isotopes. (author)
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Dynamic energy models and carbon mitigation policies
Tilley, Luke A.
In this dissertation I examine a specific class of energy models and their implications for carbon mitigation policies. The class of models includes a production function capable of reproducing the empirically observed phenomenon of short run rigidity of energy use in response to energy price changes and long run exibility of energy use in response to energy price changes. I use a theoretical model, parameterized using empirical data, to simulate economic performance under several tax regimes where taxes are levied on capital income, investment, and energy. I also investigate transitions from one tax regime to another. I find that energy taxes intended to reduce energy use can successfully achieve those goals with minimal or even positive impacts on macroeconomic performance. But the transition paths to new steady states are lengthy, making political commitment to such policies very challenging.
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A linear programming model to optimize diets in environmental policy scenarios.
Moraes, L E; Wilen, J E; Robinson, P H; Fadel, J G
2012-03-01
The objective was to develop a linear programming model to formulate diets for dairy cattle when environmental policies are present and to examine effects of these policies on diet formulation and dairy cattle nitrogen and mineral excretions as well as methane emissions. The model was developed as a minimum cost diet model. Two types of environmental policies were examined: a tax and a constraint on methane emissions. A tax was incorporated to simulate a greenhouse gas emissions tax policy, and prices of carbon credits in the current carbon markets were attributed to the methane production variable. Three independent runs were made, using carbon dioxide equivalent prices of $5, $17, and $250/t. A constraint was incorporated into the model to simulate the second type of environmental policy, reducing methane emissions by predetermined amounts. The linear programming formulation of this second alternative enabled the calculation of marginal costs of reducing methane emissions. Methane emission and manure production by dairy cows were calculated according to published equations, and nitrogen and mineral excretions were calculated by mass conservation laws. Results were compared with respect to the values generated by a base least-cost model. Current prices of the carbon credit market did not appear onerous enough to have a substantive incentive effect in reducing methane emissions and altering diet costs of our hypothetical dairy herd. However, when emissions of methane were assumed to be reduced by 5, 10, and 13.5% from the base model, total diet costs increased by 5, 19.1, and 48.5%, respectively. Either these increased costs would be passed onto the consumer or dairy producers would go out of business. Nitrogen and potassium excretions were increased by 16.5 and 16.7% with a 13.5% reduction in methane emissions from the base model. Imposing methane restrictions would further increase the demand for grains and other human-edible crops, which is not a progressive
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Hepatitis C: is there a case for universal screening in pregnancy?
LENUS (Irish Health Repository)
Martyn, F
2011-05-01
Hepatitis C (HCV) is not routinely screened for antenatally in all maternity hospitals. Most hospitals adopt a policy of targeted screening. The policy in the Coombe Women and Infants University Hospital in Dublin changed from targeted screening in 2006 to universal screening in 2007. We audited the two consecutive years. The prevalence of HCV in our antenatal population was 1.4% for 2006 (67\\/4666) when targeted screening applied and in 2007--0.71% (66\\/9222) when universal screening came into affect. One woman in 2007 would not have been detected by targeted screening--1.49% (1\\/67). Fifty five percent (37\\/67) of women were HCV-RNA positive in 2006 and 57.5% (38\\/66) were positive in 2007. We conclude that there were similar detection rates for HCV in 2006 and 2007 and that universal screening is not required if inclusive criteria for selective screening are employed but is of use in research context.
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Hepatitis C: is there a case for universal screening in pregnancy?
LENUS (Irish Health Repository)
Martyn, F
2012-02-01
Hepatitis C (HCV) is not routinely screened for antenatally in all maternity hospitals. Most hospitals adopt a policy of targeted screening. The policy in the Coombe Women and Infants University Hospital in Dublin changed from targeted screening in 2006 to universal screening in 2007. We audited the two consecutive years. The prevalence of HCV in our antenatal population was 1.4% for 2006 (67\\/4666) when targeted screening applied and in 2007--0.71% (66\\/9222) when universal screening came into affect. One woman in 2007 would not have been detected by targeted screening--1.49% (1\\/67). Fifty five percent (37\\/67) of women were HCV-RNA positive in 2006 and 57.5% (38\\/66) were positive in 2007. We conclude that there were similar detection rates for HCV in 2006 and 2007 and that universal screening is not required if inclusive criteria for selective screening are employed but is of use in research context.
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Directory of Open Access Journals (Sweden)
Pathak Sangeeta
2011-01-01
Full Text Available Background: Antibodies against only about 25-28 blood group antigens are known to cause hemolytic reactions (HTRs, and red cell antibody screening should detect such clinically significant antibodies. An extension of the antibody screening test is the ′type and screen′ done to detect clinically significant antibodies, omiting the anti-human globulin (AHG cross-match. Aim: The aim of this study was to find out if the type and screen procedure is a safe method for pre-transfusion testing when compared to the AHG cross-match currently in use in India. Materials and Methods: We evaluated data from 45373 patients for whom a total of 61668 units of packed red blood cells (PRBC were cross-matched in the AHG phase using DiaMed; ID cards. An antibody screen was carried out in all the patients using the DiaMed; ID-DiaCell I+II+III. The AHG cross-match was also carried out for all recipients, irrespective of the result of the antibody screen. The results were compared to see if there were any cases where the antibody screening was negative but the AHG cross-match showed incompatibility. Results: Not a single case was found where the antibody screen was negative and AHG cross-match showed incompatibility. In 68 cases the antibody screening was positive. Out of the 68 cases, AHG cross-match was incompatible with at least one unit of PRBC in 41 cases. Conclusion: The screening cell panel adequately detected the clinically significant antibodies in the Indian population in our study. The type and screen policy can be safe, efficient, cost-effective, and beneficial to the transfusion service in India.
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Time to refine key climate policy models
Barron, Alexander R.
2018-05-01
Ambition regarding climate change at the national level is critical but is often calibrated with the projected costs — as estimated by a small suite of energy-economic models. Weaknesses in several key areas in these models will continue to distort policy design unless collectively addressed by a diversity of researchers.
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Zhang, Qiuyi; Northridge, Mary E; Jin, Zhu; Metcalf, Sara S
2018-04-01
Increased lifespans and population growth have resulted in an older U.S. society that must reckon with the complex oral health needs that arise as adults age. Understanding accessibility to screening and treatment facilities for older adults is necessary in order to provide them with preventive and restorative services. This study uses an agent-based model to examine the accessibility of screening and treatment facilities via transportation networks for older adults living in the neighborhoods of northern Manhattan, New York City. Older adults are simulated as socioeconomically distinct agents who move along a GIS-based transportation network using transportation modes that mediate their access to screening and treatment facilities. This simulation model includes four types of mobile agents as a simplifying assumption: walk, by car, by bus, or by van (i.e., a form of transportation assistance for older adults). These mobile agents follow particular routes: older adults who travel by car, bus, and van follow street roads, whereas pedestrians follow walkways. The model enables the user to focus on one neighborhood at a time for analysis. The spatial dimension of an older adult's accessibility to screening and treatment facilities is simulated through the travel costs (indicated by travel time or distance) incurred in the GIS-based model environment, where lower travel costs to screening and treatment facilities imply better access. This model provides a framework for representing health-seeking behavior that is contextualized by a transportation network in a GIS environment.
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Directory of Open Access Journals (Sweden)
ZHU Binghua
2017-06-01
Full Text Available ObjectiveTo establish a nutritional risk screening model for patients with liver cirrhosis using discriminant analysis. MethodsThe clinical data of 273 patients with liver cirrhosis who were admitted to Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine from August 2015 to March 2016 were collected. Body height, body weight, upper arm circumference, triceps skinfold thickness, subscapular skinfold thickness, and hand grip strength were measured and recorded, and then body mass index (BMI and upper arm muscle circumference were calculated. Laboratory markers including liver function parameters, renal function parameters, and vitamins were measured. The patients were asked to complete Nutritional Risk Screening 2002 and Malnutrition Universal Screening Tool (MUST, and a self-developed nutritional risk screening pathway was used for nutritional risk classification. Observation scales of the four diagnostic methods in traditional Chinese medicine were used to collect patients′ symptoms and signs. Continuous data were expressed as mean±SD (x±s; an analysis of variance was used for comparison between multiple groups, and the least significant difference t-test was used for further comparison between two groups. Discriminant analysis was used for model establishment, and cross validation was used for model verification. ResultsThe nutritional risk screening pathway for patients with liver cirrhosis was used for the screening of respondents, and there were 49 patients (17.95% in non-risk group, 49 (17.95% in possible-risk group, and 175 (64.10% in risk group. The distance criterion function was used to establish the nutritional risk screening model for patients with liver cirrhosis: D1=-11.885+0.310×BMI+0150×MAC+0.005×P-Alb-0.001×Vit B12+0.103×Vit D-0.89×ascites-0.404×weakness-0.560×hypochondriac pain+0035×dysphoria with feverish sensation (note: if a patient has ascites, weakness, hypochondriac pain
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Modelling mobility aspects of security policies
Hartel, Pieter H.; van Eck, Pascal; Etalle, Sandro; Wieringa, Roelf J.; Barthe, G.; Burdy, L.; Huisman, Marieke; Lanet, J.-L.; Muntean, T.
Security policies are rules that constrain the behaviour of a system. Different, largely unrelated sets of rules typically govern the physical and logical worlds. However, increased hardware and software mobility forces us to consider those rules in an integrated fashion. We present SPIN models of
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A Dynamic Linear Modeling Approach to Public Policy Change
DEFF Research Database (Denmark)
Loftis, Matthew; Mortensen, Peter Bjerre
2017-01-01
Theories of public policy change, despite their differences, converge on one point of strong agreement. The relationship between policy and its causes can and does change over time. This consensus yields numerous empirical implications, but our standard analytical tools are inadequate for testing...... them. As a result, the dynamic and transformative relationships predicted by policy theories have been left largely unexplored in time-series analysis of public policy. This paper introduces dynamic linear modeling (DLM) as a useful statistical tool for exploring time-varying relationships in public...... policy. The paper offers a detailed exposition of the DLM approach and illustrates its usefulness with a time series analysis of U.S. defense policy from 1957-2010. The results point the way for a new attention to dynamics in the policy process and the paper concludes with a discussion of how...
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Mathematical modelling informs HIV prevention policy in China ...
International Development Research Centre (IDRC) Digital Library (Canada)
2016-04-27
Apr 27, 2016 ... Treatment as prevention Earlier research conducted under Modelling and controlling infectious diseases project showed that providing ... for HIV screening, diagnostics, and treatment at county and township hospitals. And in ...
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Independent screening for single-index hazard rate models with ultrahigh dimensional features
DEFF Research Database (Denmark)
Gorst-Rasmussen, Anders; Scheike, Thomas
2013-01-01
can be viewed as the natural survival equivalent of correlation screening. We state conditions under which the method admits the sure screening property within a class of single-index hazard rate models with ultrahigh dimensional features and describe the generally detrimental effect of censoring...
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Lewando Hundt, Gillian; Bryanston, Claudette; Lowe, Pam; Cross, Saul; Sandall, Jane; Spencer, Kevin
2011-01-01
Background The role of applied theatre in engaging both lay and professional publics with debate on health policy and practice is an emergent field. This paper discusses the development, production performance and discussion of ‘Inside View’.\\ud \\ud Objectives The objectives were to produce applied theatre from research findings of a completed study on genetic prenatal screening, exploring the dilemmas for women and health professionals of prenatal genetic screening, and to engage audiences i...
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Buyze, J; Vanden Berghe, W; Hens, N; Kenyon, C
2018-02-01
There is considerable uncertainty as to the effectiveness of Neisseria gonorrhoeae (NG) screening in men who have sex with men. It is important to ensure that screening has benefits that outweigh the risks of increased antibiotics resistance. We develop a mathematical model to estimate the effectiveness of screening on prevalence. Separable Temporal Exponential family Random Graph Models are used to model the sexual relationships network, both with main and casual partners. Next, the transmission of Gonorrhoea is simulated on this network. The models are implemented using the R package 'statnet', which we adapted among other things to incorporate infection status at the pharynx, urethra and rectum separately and to distinguish between anal sex, oral sex and rimming. The different screening programmes compared are no screening, 3.5% of the population screened, 32% screened and 50% screened. The model simulates day-by-day evolution for 10 years of a population of 10 000. If half of the population would be screened, the prevalence in the pharynx decreases from 11.9% to 10.2%. We conclude that the limited impact of screening on NG prevalence may not outweigh the increased risk of antibiotic resistance.
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Estimation of the applicability domain of kernel-based machine learning models for virtual screening
Directory of Open Access Journals (Sweden)
Fechner Nikolas
2010-03-01
Full Text Available Abstract Background The virtual screening of large compound databases is an important application of structural-activity relationship models. Due to the high structural diversity of these data sets, it is impossible for machine learning based QSAR models, which rely on a specific training set, to give reliable results for all compounds. Thus, it is important to consider the subset of the chemical space in which the model is applicable. The approaches to this problem that have been published so far mostly use vectorial descriptor representations to define this domain of applicability of the model. Unfortunately, these cannot be extended easily to structured kernel-based machine learning models. For this reason, we propose three approaches to estimate the domain of applicability of a kernel-based QSAR model. Results We evaluated three kernel-based applicability domain estimations using three different structured kernels on three virtual screening tasks. Each experiment consisted of the training of a kernel-based QSAR model using support vector regression and the ranking of a disjoint screening data set according to the predicted activity. For each prediction, the applicability of the model for the respective compound is quantitatively described using a score obtained by an applicability domain formulation. The suitability of the applicability domain estimation is evaluated by comparing the model performance on the subsets of the screening data sets obtained by different thresholds for the applicability scores. This comparison indicates that it is possible to separate the part of the chemspace, in which the model gives reliable predictions, from the part consisting of structures too dissimilar to the training set to apply the model successfully. A closer inspection reveals that the virtual screening performance of the model is considerably improved if half of the molecules, those with the lowest applicability scores, are omitted from the screening
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Fechner, Nikolas; Jahn, Andreas; Hinselmann, Georg; Zell, Andreas
2010-03-11
The virtual screening of large compound databases is an important application of structural-activity relationship models. Due to the high structural diversity of these data sets, it is impossible for machine learning based QSAR models, which rely on a specific training set, to give reliable results for all compounds. Thus, it is important to consider the subset of the chemical space in which the model is applicable. The approaches to this problem that have been published so far mostly use vectorial descriptor representations to define this domain of applicability of the model. Unfortunately, these cannot be extended easily to structured kernel-based machine learning models. For this reason, we propose three approaches to estimate the domain of applicability of a kernel-based QSAR model. We evaluated three kernel-based applicability domain estimations using three different structured kernels on three virtual screening tasks. Each experiment consisted of the training of a kernel-based QSAR model using support vector regression and the ranking of a disjoint screening data set according to the predicted activity. For each prediction, the applicability of the model for the respective compound is quantitatively described using a score obtained by an applicability domain formulation. The suitability of the applicability domain estimation is evaluated by comparing the model performance on the subsets of the screening data sets obtained by different thresholds for the applicability scores. This comparison indicates that it is possible to separate the part of the chemspace, in which the model gives reliable predictions, from the part consisting of structures too dissimilar to the training set to apply the model successfully. A closer inspection reveals that the virtual screening performance of the model is considerably improved if half of the molecules, those with the lowest applicability scores, are omitted from the screening. The proposed applicability domain formulations
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Modelling issues on climate change policies. A discussion of the GTAP-E model
Energy Technology Data Exchange (ETDEWEB)
Kremers, H.; Nijkamp, P.; Wang, Shunli [Department of Spatial Economics, Free University, Amsterdam (Netherlands)
2000-11-01
Ater the Kyoto agreements the need has arisen to trace the implications of various international environmental strategies. In this paper, we discuss relevant modelling issues of incorporating important environmental policy measures in one of the popular applied general equilibrium models for international trade, the so-called GTAP model. Special attention is paid to an extended version, the GTAP-E (Global Trade Analysis Project - Energy) by addressing the question how to include the widely discussed instruments of International Emission Trading, Joint Implementation, and Clean Development Mechanisms. The paper will be concluded with some policy issues. 10 refs.
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Modelling issues on climate change policies. A discussion of the GTAP-E model
International Nuclear Information System (INIS)
Kremers, H.; Nijkamp, P.; Wang, Shunli
2000-01-01
Ater the Kyoto agreements the need has arisen to trace the implications of various international environmental strategies. In this paper, we discuss relevant modelling issues of incorporating important environmental policy measures in one of the popular applied general equilibrium models for international trade, the so-called GTAP model. Special attention is paid to an extended version, the GTAP-E (Global Trade Analysis Project - Energy) by addressing the question how to include the widely discussed instruments of International Emission Trading, Joint Implementation, and Clean Development Mechanisms. The paper will be concluded with some policy issues. 10 refs
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An Integrative Behavioral Model of Information Security Policy Compliance
Directory of Open Access Journals (Sweden)
Sang Hoon Kim
2014-01-01
Full Text Available The authors found the behavioral factors that influence the organization members’ compliance with the information security policy in organizations on the basis of neutralization theory, Theory of planned behavior, and protection motivation theory. Depending on the theory of planned behavior, members’ attitudes towards compliance, as well as normative belief and self-efficacy, were believed to determine the intention to comply with the information security policy. Neutralization theory, a prominent theory in criminology, could be expected to provide the explanation for information system security policy violations. Based on the protection motivation theory, it was inferred that the expected efficacy could have an impact on intentions of compliance. By the above logical reasoning, the integrative behavioral model and eight hypotheses could be derived. Data were collected by conducting a survey; 194 out of 207 questionnaires were available. The test of the causal model was conducted by PLS. The reliability, validity, and model fit were found to be statistically significant. The results of the hypotheses tests showed that seven of the eight hypotheses were acceptable. The theoretical implications of this study are as follows: (1 the study is expected to play a role of the baseline for future research about organization members’ compliance with the information security policy, (2 the study attempted an interdisciplinary approach by combining psychology and information system security research, and (3 the study suggested concrete operational definitions of influencing factors for information security policy compliance through a comprehensive theoretical review. Also, the study has some practical implications. First, it can provide the guideline to support the successful execution of the strategic establishment for the implement of information system security policies in organizations. Second, it proves that the need of education and training
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An integrative behavioral model of information security policy compliance.
Kim, Sang Hoon; Yang, Kyung Hoon; Park, Sunyoung
2014-01-01
The authors found the behavioral factors that influence the organization members' compliance with the information security policy in organizations on the basis of neutralization theory, Theory of planned behavior, and protection motivation theory. Depending on the theory of planned behavior, members' attitudes towards compliance, as well as normative belief and self-efficacy, were believed to determine the intention to comply with the information security policy. Neutralization theory, a prominent theory in criminology, could be expected to provide the explanation for information system security policy violations. Based on the protection motivation theory, it was inferred that the expected efficacy could have an impact on intentions of compliance. By the above logical reasoning, the integrative behavioral model and eight hypotheses could be derived. Data were collected by conducting a survey; 194 out of 207 questionnaires were available. The test of the causal model was conducted by PLS. The reliability, validity, and model fit were found to be statistically significant. The results of the hypotheses tests showed that seven of the eight hypotheses were acceptable. The theoretical implications of this study are as follows: (1) the study is expected to play a role of the baseline for future research about organization members' compliance with the information security policy, (2) the study attempted an interdisciplinary approach by combining psychology and information system security research, and (3) the study suggested concrete operational definitions of influencing factors for information security policy compliance through a comprehensive theoretical review. Also, the study has some practical implications. First, it can provide the guideline to support the successful execution of the strategic establishment for the implement of information system security policies in organizations. Second, it proves that the need of education and training programs suppressing
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Economic model of a birth cohort screening program for hepatitis C virus.
McGarry, Lisa J; Pawar, Vivek S; Panchmatia, Hemangi R; Rubin, Jaime L; Davis, Gary L; Younossi, Zobair M; Capretta, James C; O'Grady, Michael J; Weinstein, Milton C
2012-05-01
Recent research has identified high hepatitis C virus (HCV) prevalence among older U.S. residents who contracted HCV decades ago and may no longer be recognized as high risk. We assessed the cost-effectiveness of screening 100% of U.S. residents born 1946-1970 over 5 years (birth-cohort screening), compared with current risk-based screening, by projecting costs and outcomes of screening over the remaining lifetime of this birth cohort. A Markov model of the natural history of HCV was developed using data synthesized from surveillance data, published literature, expert opinion, and other secondary sources. We assumed eligible patients were treated with pegylated interferon plus ribavirin, with genotype 1 patients receiving a direct-acting antiviral in combination. The target population is U.S. residents born 1946-1970 with no previous HCV diagnosis. Among the estimated 102 million (1.6 million chronically HCV infected) eligible for screening, birth-cohort screening leads to 84,000 fewer cases of decompensated cirrhosis, 46,000 fewer cases of hepatocellular carcinoma, 10,000 fewer liver transplants, and 78,000 fewer HCV-related deaths. Birth-cohort screening leads to higher overall costs than risk-based screening ($80.4 billion versus $53.7 billion), but yields lower costs related to advanced liver disease ($31.2 billion versus $39.8 billion); birth-cohort screening produces an incremental cost-effectiveness ratio (ICER) of $37,700 per quality-adjusted life year gained versus risk-based screening. Sensitivity analyses showed that reducing the time horizon during which health and economic consequences are evaluated increases the ICER; similarly, decreasing the treatment rates and efficacy increases the ICER. Model results were relatively insensitive to other inputs. Birth-cohort screening for HCV is likely to provide important health benefits by reducing lifetime cases of advanced liver disease and HCV-related deaths and is cost-effective at conventional willingness
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Alcohol and drug policy model for the Canadian upstream petroleum industry
Energy Technology Data Exchange (ETDEWEB)
NONE
2007-09-15
This alcohol and drug policy model was developed to help employers manage and reduce the risks associated with drug and alcohol use in the workplace. The policy model outlined guidelines for establishing and implementing drug and alcohol policies, and discussed treatment programs and opportunities for re-employment. The model was developed by Enform, the upstream petroleum industry's safety and training arm, who used a previous guide developed by the Construction Owner's Association of Alberta (COAA) as a model. Enform's model provided a summary of key accountabilities across all levels of industry as well as the accepted minimum criteria for developing alcohol and drug policies. The model included guidelines and recommendations for employees, supervisors, and owners, employers, and contractors. The responsibilities of associations, organizations, and private companies were also outlined. An overview of recommended implementation plans was provided, as well as details of alcohol and drug use education programs and workplace rules. A supervisor's guide to implementation provided outlines of the causes of drug use among employees. tabs.
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Quantification model of the consequences of monetary policy shocks
Directory of Open Access Journals (Sweden)
Coralia Emilia POPA
2017-11-01
Full Text Available The monetary analysis based on the BVAR (Bayesian Vector Autoregression model is extremely important in the monetary policy implementation strategy, the information provided is important not only for the Central Bank, but also for the economic agents and the population. Therefore, conducting this analysis at the level of Romania helps to understand better the mechanism by which monetary policy is transmitted in order to achieve the set target, namely inflation targeting, but it also provides us with important information regarding the accession to the euro area. The model we are trying to test helps us understand through the correlations between the interest rate, GDP and the inflation rate how monetary policy responds to shocks. The model follows the methodology presented by Sims and Zha (1998 in the paper "Bayesian Methods for Dynamic Multivariate Models and Using the Bayesian Autoregressive Vector". In the analysis of this model, quarterly data for a minimum of three years, three variables are used to make the results relevant. The data needed to model the model are used in logarithmic form, except for the interest rate, and the outcome is applied to a differentiated premium operator. Of the variables used, the interest rate is the only one that does not allow seasonal adjustment.
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UK energy policy ambition and UK energy modelling-fit for purpose?
International Nuclear Information System (INIS)
Strachan, Neil
2011-01-01
Aiming to lead amongst other G20 countries, the UK government has classified the twin energy policy priorities of decarbonisation and security of supply as a 'centennial challenge'. This viewpoint discusses the UK's capacity for energy modelling and scenario building as a critical underpinning of iterative decision making to meet these policy ambitions. From a nadir, over the last decade UK modelling expertise has been steadily built up. However extreme challenges remain in the level and consistency of funding of core model teams - critical to ensure a full scope of energy model types and hence insights, and in developing new state-of-the-art models to address evolving uncertainties. Meeting this challenge will facilitate a broad scope of types and geographical scale of UK's analytical tools to responsively deliver the evidence base for a range of public and private sector decision makers, and ensure that the UK contributes to global efforts to advance the field of energy-economic modelling. - Research highlights: → Energy modelling capacity is a critical underpinning for iterative energy policy making. → Full scope of energy models and analytical approaches is required. → Extreme challenges remain in consistent and sustainable funding of energy modelling teams. → National governments that lead in global energy policy also need to invest in modelling capacity.
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Evanoff, Bradley; Kymes, Steve
2010-06-01
The aim of this study was to evaluate the costs associated with pre-employment nerve conduction testing as a screening tool for carpal tunnel syndrome (CTS) in the workplace. We used a Markov decision analysis model to compare the costs associated with a strategy of screening all prospective employees for CTS and not hiring those with abnormal nerve conduction, versus a strategy of not screening for CTS. The variables included in our model included employee turnover rate, the incidence of CTS, the prevalence of median nerve conduction abnormalities, the relative risk of developing CTS conferred by abnormal nerve conduction screening, the costs of pre-employment screening, and the worker's compensation costs to the employer for each case of CTS. In our base case, total employer costs for CTS from the perspective of the employer (cost of screening plus costs for workers' compensation associated with CTS) were higher when screening was used. Median costs per employee position over five years were US$503 for the screening strategy versus US$200 for a no-screening strategy. A sensitivity analysis showed that a strategy of screening was cost-beneficial from the perspective of the employer only under a few circumstances. Using Monte Carlo simulation varying all parameters, we found a 30% probability that screening would be cost-beneficial. A strategy of pre-employment screening for CTS should be carefully evaluated for yield and social consequences before being implemented. Our model suggests such screening is not appropriate for most employers.
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Abnormal screening in the quantum disordered phases of nonlinear σ-models
International Nuclear Information System (INIS)
Wen, X.G.; Zee, A.
1989-01-01
We study some properties of the quantum disordered phase of nonlinear σ-models, focussing on the quantum numbers of the quasi-particles and possible experimental implications. We find that the quasi-particles in the quantum disordered phase may, in many cases, carry new quantum numbers which do not appear in any finite combination of the fundamental fields. We call this phenomenon abnormal screening. Abnormal screening is shown to appear in (1+1)-dimensional systems. Using a large N mean field approach to the quantum disordered state, we show that abnormal screening may also appear in (1+2)-dimensional nonlinear σ-models. In 1+2 dimensions abnormal screening is closely related to spin-charge separation, which was proposed to occur in the spin liquid state relevant in some theories of high T c superconductivity. We compare the mean field approach with bosonization and other exact results for (1+1)-dimensional systems and find exact agreement for the quantum numbers of the quasi-particles. This suggests that mean field analysis of high T c superconductivity may yield a qualitatively reliable picture. Our result also gives an alternative way of understanding some novel properties of the antiferromagnetic spin chain. We estimate the density and temperature at which deconfinement and abnormal screening occur. Finally, we suggest some experimental signatures for this phenomenon. (orig.)
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DEFF Research Database (Denmark)
Hansen, Suzanne L.; Sterjev, Zoran; Werngreen, Marie
2012-01-01
The cortical wedge is a commonly applied model for in vitro screening of new antiepileptic drugs (AEDs) and has been extensively used in characterization of well-known AEDs. However, the predictive validity of this model as a screening model has been questioned as, e.g., carbamazepine has been...... screening model for AEDs. To this end, we compared the in vitro and in vivo pharmacological profile of several selected AEDs (phenobarbital, phenytoin, tiagabine, fosphenytoin, valproate, and carbamazepine) along with citalopram using the PTZ-kindled model and brain slices from naïve, saline...
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Zee, van der, F.A.
1997-01-01
This study explores the relevance and applicability of political economy models for the explanation of agricultural policies. Part I (chapters 4-7) takes a general perspective and evaluates the empirical applicability of voting models and interest group models to agricultural policy formation in industrialised market economics. Part II (chapters 8-11) focuses on the empirical applicability of political economy models to agricultural policy formation and agricultural policy developmen...
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Directory of Open Access Journals (Sweden)
Teerawattananon Yot
2010-07-01
Full Text Available Abstract Background Screening tests for cervical cancer are effective in reducing the disease burden. In Thailand, a Pap smear program has been implemented throughout the country for 40 years. In 2008 the Ministry of Public Health (MoPH unexpectedly decided to scale up the coverage of free cervical cancer screening services, to meet an ambitious target. This study analyzes the processes and factors that drove this policy innovation in the area of cervical cancer control in Thailand. Methods In-depth interviews with key policy actors and review of relevant documents were conducted in 2009. Data analysis was guided by a framework, developed on public policy models and existing literature on scaling-up health care interventions. Results Between 2006 and 2008 international organizations and the vaccine industry advocated the introduction of Human Papillomavirus (HPV vaccine for the primary prevention of cervical cancer. Meanwhile, a local study suggested that the vaccine was considerably less cost-effective than cervical cancer screening in the Thai context. Then, from August to December 2008, the MoPH carried out a campaign to expand the coverage of its cervical cancer screening program, targeting one million women. The study reveals that several factors were influential in focusing the attention of policymakers on strengthening the screening services. These included the high burden of cervical cancer in Thailand, the launch of the HPV vaccine onto the global and domestic markets, the country’s political instability, and the dissemination of scientific evidence regarding the appropriateness of different options for cervical cancer prevention. Influenced by the country’s political crisis, the MoPH’s campaign was devised in a very short time. In the view of the responsible health officials, the campaign was not successful and indeed, did not achieve its ambitious target. Conclusion The Thai case study suggests that the political crisis was a
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Yothasamut, Jomkwan; Putchong, Choenkwan; Sirisamutr, Teera; Teerawattananon, Yot; Tantivess, Sripen
2010-07-02
Screening tests for cervical cancer are effective in reducing the disease burden. In Thailand, a Pap smear program has been implemented throughout the country for 40 years. In 2008 the Ministry of Public Health (MoPH) unexpectedly decided to scale up the coverage of free cervical cancer screening services, to meet an ambitious target. This study analyzes the processes and factors that drove this policy innovation in the area of cervical cancer control in Thailand. In-depth interviews with key policy actors and review of relevant documents were conducted in 2009. Data analysis was guided by a framework, developed on public policy models and existing literature on scaling-up health care interventions. Between 2006 and 2008 international organizations and the vaccine industry advocated the introduction of Human Papillomavirus (HPV) vaccine for the primary prevention of cervical cancer. Meanwhile, a local study suggested that the vaccine was considerably less cost-effective than cervical cancer screening in the Thai context. Then, from August to December 2008, the MoPH carried out a campaign to expand the coverage of its cervical cancer screening program, targeting one million women. The study reveals that several factors were influential in focusing the attention of policymakers on strengthening the screening services. These included the high burden of cervical cancer in Thailand, the launch of the HPV vaccine onto the global and domestic markets, the country's political instability, and the dissemination of scientific evidence regarding the appropriateness of different options for cervical cancer prevention. Influenced by the country's political crisis, the MoPH's campaign was devised in a very short time. In the view of the responsible health officials, the campaign was not successful and indeed, did not achieve its ambitious target. The Thai case study suggests that the political crisis was a crucial factor that drew the attention of policymakers to the cervical
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Directory of Open Access Journals (Sweden)
Christopher Fuller
Full Text Available The English Department of Health introduced universal MRSA screening of admissions to English hospitals in 2010. It commissioned a national audit to review implementation, impact on patient management, admission prevalence and extra yield of MRSA identified compared to "high-risk" specialty or "checklist-activated" screening (CLAS of patients with MRSA risk factors.National audit May 2011. Questionnaires to infection control teams in all English NHS acute trusts, requesting number patients admitted and screened, new or previously known MRSA; MRSA point prevalence; screening and isolation policies; individual risk factors and patient management for all new MRSA patients and random sample of negatives.144/167 (86.2% trusts responded. Individual patient data for 760 new MRSA patients and 951 negatives. 61% of emergency admissions (median 67.3%, 81% (median 59.4% electives and 47% (median 41.4% day-cases were screened. MRSA admission prevalence: 1% (median 0.9% emergencies, 0.6% (median 0.4% electives, 0.4% (median 0% day-cases. Approximately 50% all MRSA identified was new. Inpatient MRSA point prevalence: 3.3% (median 2.9%. 104 (77% trusts pre-emptively isolated patients with previous MRSA, 63 (35% pre-emptively isolated admissions to "high-risk" specialties; 7 (5% used PCR routinely. Mean time to MRSA positive result: 2.87 days (±1.33; 37% (219/596 newly identified MRSA patients discharged before result available; 55% remainder (205/376 isolated post-result. In an average trust, CLAS would reduce screening by 50%, identifying 81% of all MRSA. "High risk" specialty screening would reduce screening by 89%, identifying 9% of MRSA.Implementation of universal screening was poor. Admission prevalence (new cases was low. CLAS reduced screening effort for minor decreases in identification, but implementation may prove difficult. Cost effectiveness of this and other policies, awaits evaluation by transmission dynamic economic modelling, using data from
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Fuller, Christopher; Robotham, Julie; Savage, Joanne; Hopkins, Susan; Deeny, Sarah R; Stone, Sheldon; Cookson, Barry
2013-01-01
The English Department of Health introduced universal MRSA screening of admissions to English hospitals in 2010. It commissioned a national audit to review implementation, impact on patient management, admission prevalence and extra yield of MRSA identified compared to "high-risk" specialty or "checklist-activated" screening (CLAS) of patients with MRSA risk factors. National audit May 2011. Questionnaires to infection control teams in all English NHS acute trusts, requesting number patients admitted and screened, new or previously known MRSA; MRSA point prevalence; screening and isolation policies; individual risk factors and patient management for all new MRSA patients and random sample of negatives. 144/167 (86.2%) trusts responded. Individual patient data for 760 new MRSA patients and 951 negatives. 61% of emergency admissions (median 67.3%), 81% (median 59.4%) electives and 47% (median 41.4%) day-cases were screened. MRSA admission prevalence: 1% (median 0.9%) emergencies, 0.6% (median 0.4%) electives, 0.4% (median 0%) day-cases. Approximately 50% all MRSA identified was new. Inpatient MRSA point prevalence: 3.3% (median 2.9%). 104 (77%) trusts pre-emptively isolated patients with previous MRSA, 63 (35%) pre-emptively isolated admissions to "high-risk" specialties; 7 (5%) used PCR routinely. Mean time to MRSA positive result: 2.87 days (±1.33); 37% (219/596) newly identified MRSA patients discharged before result available; 55% remainder (205/376) isolated post-result. In an average trust, CLAS would reduce screening by 50%, identifying 81% of all MRSA. "High risk" specialty screening would reduce screening by 89%, identifying 9% of MRSA. Implementation of universal screening was poor. Admission prevalence (new cases) was low. CLAS reduced screening effort for minor decreases in identification, but implementation may prove difficult. Cost effectiveness of this and other policies, awaits evaluation by transmission dynamic economic modelling, using data from
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Maternal Serologic Screening to Prevent Congenital Toxoplasmosis: A Decision-Analytic Economic Model
Stillwaggon, Eileen; Carrier, Christopher S.; Sautter, Mari; McLeod, Rima
2011-01-01
Objective To determine a cost-minimizing option for congenital toxoplasmosis in the United States. Methodology/Principal Findings A decision-analytic and cost-minimization model was constructed to compare monthly maternal serological screening, prenatal treatment, and post-natal follow-up and treatment according to the current French (Paris) protocol, versus no systematic screening or perinatal treatment. Costs are based on published estimates of lifetime societal costs of developmental disabilities and current diagnostic and treatment costs. Probabilities are based on published results and clinical practice in the United States and France. One- and two-way sensitivity analyses are used to evaluate robustness of results. Universal monthly maternal screening for congenital toxoplasmosis with follow-up and treatment, following the French protocol, is found to be cost-saving, with savings of $620 per child screened. Results are robust to changes in test costs, value of statistical life, seroprevalence in women of childbearing age, fetal loss due to amniocentesis, and to bivariate analysis of test costs and incidence of primary T. gondii infection in pregnancy. Given the parameters in this model and a maternal screening test cost of $12, screening is cost-saving for rates of congenital infection above 1 per 10,000 live births. If universal testing generates economies of scale in diagnostic tools—lowering test costs to about $2 per test—universal screening is cost-saving at rates of congenital infection well below the lowest reported rates in the United States of 1 per 10,000 live births. Conclusion/Significance Universal screening according to the French protocol is cost saving for the US population within broad parameters for costs and probabilities. PMID:21980546
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Evaluating energy efficiency policies with energy-economy models
Mundaca, L.; Neij, L.; Worrell, E.; McNeil, M.
2010-01-01
The growing complexities of energy systems, environmental problems, and technology markets are driving and testing most energy-economy models to their limits. To further advance bottom-up models from a multidisciplinary energy efficiency policy evaluation perspective, we review and critically
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Computational Models Used to Assess US Tobacco Control Policies.
Feirman, Shari P; Glasser, Allison M; Rose, Shyanika; Niaura, Ray; Abrams, David B; Teplitskaya, Lyubov; Villanti, Andrea C
2017-11-01
Simulation models can be used to evaluate existing and potential tobacco control interventions, including policies. The purpose of this systematic review was to synthesize evidence from computational models used to project population-level effects of tobacco control interventions. We provide recommendations to strengthen simulation models that evaluate tobacco control interventions. Studies were eligible for review if they employed a computational model to predict the expected effects of a non-clinical US-based tobacco control intervention. We searched five electronic databases on July 1, 2013 with no date restrictions and synthesized studies qualitatively. Six primary non-clinical intervention types were examined across the 40 studies: taxation, youth prevention, smoke-free policies, mass media campaigns, marketing/advertising restrictions, and product regulation. Simulation models demonstrated the independent and combined effects of these interventions on decreasing projected future smoking prevalence. Taxation effects were the most robust, as studies examining other interventions exhibited substantial heterogeneity with regard to the outcomes and specific policies examined across models. Models should project the impact of interventions on overall tobacco use, including nicotine delivery product use, to estimate preventable health and cost-saving outcomes. Model validation, transparency, more sophisticated models, and modeling policy interactions are also needed to inform policymakers to make decisions that will minimize harm and maximize health. In this systematic review, evidence from multiple studies demonstrated the independent effect of taxation on decreasing future smoking prevalence, and models for other tobacco control interventions showed that these strategies are expected to decrease smoking, benefit population health, and are reasonable to implement from a cost perspective. Our recommendations aim to help policymakers and researchers minimize harm and
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Modelling of hysteresis in thin superconducting screens for mixed-mu suspension systems
International Nuclear Information System (INIS)
Asher, G.M.; Williams, J.T.; Walters, C.R.; Joyce, H.; Paul, R.J.A.
1982-01-01
Mixed-mu levitation is the principle whereby iron is levitated in a magnetic field and stabilized by the proximity of diamagnetic superconducting screens. In a dynamic environment, the screens are subject to changing magnetic fields thus causing hysteresis losses in the superconducting material. This paper is concerned with the modeling of such hysteresis. A finite difference approximation to the current and field distributions is employed, the current distribution being made consistent with critical current values by iteration. Square and disc shaped screen samples are studied and hysteresis curves computed. It is shown that the method represents a fair approximation to the hysteresis behavior of thin superconducting screens. 8 refs
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Policy Model of Sustainable Infrastructure Development (Case Study : Bandarlampung City, Indonesia)
Persada, C.; Sitorus, S. R. P.; Marimin; Djakapermana, R. D.
2018-03-01
Infrastructure development does not only affect the economic aspect, but also social and environmental, those are the main dimensions of sustainable development. Many aspects and actors involved in urban infrastructure development requires a comprehensive and integrated policy towards sustainability. Therefore, it is necessary to formulate an infrastructure development policy that considers various dimensions of sustainable development. The main objective of this research is to formulate policy of sustainable infrastructure development. In this research, urban infrastructure covers transportation, water systems (drinking water, storm water, wastewater), green open spaces and solid waste. This research was conducted in Bandarlampung City. This study use a comprehensive modeling, namely the Multi Dimensional Scaling (MDS) with Rapid Appraisal of Infrastructure (Rapinfra), it uses of Analytic Network Process (ANP) and it uses system dynamics model. The findings of the MDS analysis showed that the status of Bandarlampung City infrastructure sustainability is less sustainable. The ANP analysis produces 8 main indicators of the most influential in the development of sustainable infrastructure. The system dynamics model offered 4 scenarios of sustainable urban infrastructure policy model. The best scenario was implemented into 3 policies consist of: the integrated infrastructure management, the population control, and the local economy development.
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Energy modelling platforms for policy and strategy support
International Nuclear Information System (INIS)
Dyner, I.
2000-01-01
The energy field has been dominated by 'hard' modelling approaches by researchers from engineering and economics discipline. The recent trend towards a more liberalised environment moves away from central planning to market-based resource allocation, leading to the creation and use of strategic tools, with much 'softer' specifications, in the 'system-thinking' tradition. This paper presents the use of system dynamics in a generalised way, to provide a platform for integrated energy analysis. Issues of modularity and policy evolution are important in the design of the modelling platform to facilitate its use, and reuse. Hence the concepts of a platform, rather than a model, has to be implemented in a coherent way if it is to provide sustained value for ongoing support to both government policy and corporate strategy. (author)
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Tobacco Town: Computational Modeling of Policy Options to Reduce Tobacco Retailer Density.
Luke, Douglas A; Hammond, Ross A; Combs, Todd; Sorg, Amy; Kasman, Matt; Mack-Crane, Austen; Ribisl, Kurt M; Henriksen, Lisa
2017-05-01
To identify the behavioral mechanisms and effects of tobacco control policies designed to reduce tobacco retailer density. We developed the Tobacco Town agent-based simulation model to examine 4 types of retailer reduction policies: (1) random retailer reduction, (2) restriction by type of retailer, (3) limiting proximity of retailers to schools, and (4) limiting proximity of retailers to each other. The model examined the effects of these policies alone and in combination across 4 different types of towns, defined by 2 levels of population density (urban vs suburban) and 2 levels of income (higher vs lower). Model results indicated that reduction of retailer density has the potential to decrease accessibility of tobacco products by driving up search and purchase costs. Policy effects varied by town type: proximity policies worked better in dense, urban towns whereas retailer type and random retailer reduction worked better in less-dense, suburban settings. Comprehensive retailer density reduction policies have excellent potential to reduce the public health burden of tobacco use in communities.
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Renewable energy policy evaluation using real option model. The case of Taiwan
International Nuclear Information System (INIS)
Lee, Shun-Chung; Shih, Li-Hsing
2010-01-01
This study presents a policy benefit evaluation model that integrates cost efficiency curve information on renewable power generation technologies into real options analysis (ROA) methods. The proposed model evaluates quantitatively the policy value provided by developing renewable energy (RE) in the face of uncertain fossil fuel prices and RE policy-related factors. The economic intuition underlying the policy-making process is elucidated, while empirical analysis illustrates the option value embedded in the current development policy in Taiwan for wind power. In addition to revealing the benefits that RE development provides when considering real options, analytical results indicate that ROA is a highly effective means of quantifying how policy planning uncertainty including managerial flexibility influences RE development. In addition to assessing the policy value of current RE development policy, this study also compares policy values in terms of internalized external costs and varying feed-in tariff (FIT). Simulation results demonstrate that the RE development policy with internalized CO 2 emission costs is appropriate policy planning from sustainability point of view. Furthermore, relationship between varying FIT and policy values can be shown quantitatively and appropriate FIT level could be determined accordingly. (author)
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Directory of Open Access Journals (Sweden)
Raik Kuhlisch
2017-07-01
Full Text Available This article discusses potential clashes between different types of security policies that regulate resource access requests on clinical patient data in hospitals by employees. Attribute-based Access Control (ABAC is proposed as a proper means for such regulation. A proper representation of ABAC policies must include a handling of policy attributes among different policy types. In this article, we propose a semantic policy model with predefined policy conflict categories. A conformance verification function detects erroneous, clashing or mutually susceptible rules early during the policy planning phase. The model and conflicts are used in a conceptual application environment and evaluated in a technical experiment during an interoperability test event.
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Modeling a point-source release of 1,1,1-trichloroethane using EPA's SCREEN model
International Nuclear Information System (INIS)
Henriques, W.D.; Dixon, K.R.
1994-01-01
Using data from the Environmental Protection Agency's Toxic Release Inventory 1988 (EPA TRI88), pollutant concentration estimates were modeled for a point source air release of 1,1,1-trichloroethane at the Savannah River Plant located in Aiken, South Carolina. Estimates were calculating using the EPA's SCREEN model utilizing typical meteorological conditions to determine maximum impact of the plume under different mixing conditions for locations within 100 meters of the stack. Input data for the SCREEN model were then manipulated to simulate the impact of the release under urban conditions (for the purpose of assessing future landuse considerations) and under flare release options to determine if these parameters lessen or increase the probability of human or wildlife exposure to significant concentrations. The results were then compared to EPA reference concentrations (RfC) in order to assess the size of the buffer around the stack which may potentially have levels that exceed this level of safety
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MONETARY POLICY TRANSMISSION MECHANISM AND TVP-VAR MODEL
Directory of Open Access Journals (Sweden)
Andreea ROŞOIU
2013-12-01
Full Text Available The transmission of monetary policy to the economy is a subject of major importance for central banks because, by using these measures, central banks can achieve their purpose of ensuring price stability without neglecting the objective of sustainable economic growth. In order to analyze the evolution of the monetary policy transmission mechanism in Romania, a time varying structural vector autoregression model is estimated, by using a Markov Chain Monte Carlo algorithm for the posterior evolution. The conclusions of the empirical study are: both systematic and non-systematic monetary policy have changed during the investigated period of time, the systematic response of the interest rate to shocks in inflation and unemployment being faster over the recent period. Also, non-policy shocks seem more important than interest rate shocks in explaining inflation and unemployment evolution.
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Sabik, Lindsay M; Dahman, Bassam; Vichare, Anushree; Bradley, Cathy J
2018-05-01
Medicaid-insured women have low rates of cancer screening. There are multiple policy levers that may influence access to preventive services such as screening, including physician payment and managed care. We examine the relationship between each of these factors and breast and cervical cancer screening among nonelderly nondisabled adult Medicaid enrollees. We combine individual-level data on Medicaid enrollment, demographics, and use of screening services from the Medicaid Analytic eXtract files with data on states' Medicaid-to-Medicare fee ratios and estimate their impact on screening services. Higher physician fees are associated with greater screening for comprehensive managed care enrollees; for enrollees in fee-for-service Medicaid, the findings are mixed. Patient participation in primary care case management is a significant moderator of the relationship between physician fees and the rate of screening, as interactions between enrollee primary care case management status and the Medicaid fee ratio are consistently positive across models of screening.
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Trentham-Dietz, Amy; Kerlikowske, Karla; Stout, Natasha K; Miglioretti, Diana L; Schechter, Clyde B; Ergun, Mehmet Ali; van den Broek, Jeroen J; Alagoz, Oguzhan; Sprague, Brian L; van Ravesteyn, Nicolien T; Near, Aimee M; Gangnon, Ronald E; Hampton, John M; Chandler, Young; de Koning, Harry J; Mandelblatt, Jeanne S; Tosteson, Anna N A
2016-11-15
Biennial screening is generally recommended for average-risk women aged 50 to 74 years, but tailored screening may provide greater benefits. To estimate outcomes for various screening intervals after age 50 years based on breast density and risk for breast cancer. Collaborative simulation modeling using national incidence, breast density, and screening performance data. United States. Women aged 50 years or older with various combinations of breast density and relative risk (RR) of 1.0, 1.3, 2.0, or 4.0. Annual, biennial, or triennial digital mammography screening from ages 50 to 74 years (vs. no screening) and ages 65 to 74 years (vs. biennial digital mammography from ages 50 to 64 years). Lifetime breast cancer deaths, life expectancy and quality-adjusted life-years (QALYs), false-positive mammograms, benign biopsy results, overdiagnosis, cost-effectiveness, and ratio of false-positive results to breast cancer deaths averted. Screening benefits and overdiagnosis increase with breast density and RR. False-positive mammograms and benign results on biopsy decrease with increasing risk. Among women with fatty breasts or scattered fibroglandular density and an RR of 1.0 or 1.3, breast cancer deaths averted were similar for triennial versus biennial screening for both age groups (50 to 74 years, median of 3.4 to 5.1 vs. 4.1 to 6.5 deaths averted; 65 to 74 years, median of 1.5 to 2.1 vs. 1.8 to 2.6 deaths averted). Breast cancer deaths averted increased with annual versus biennial screening for women aged 50 to 74 years at all levels of breast density and an RR of 4.0, and those aged 65 to 74 years with heterogeneously or extremely dense breasts and an RR of 4.0. However, harms were almost 2-fold higher. Triennial screening for the average-risk subgroup and annual screening for the highest-risk subgroup cost less than $100 000 per QALY gained. Models did not consider women younger than 50 years, those with an RR less than 1, or other imaging methods. Average-risk women
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An Affinity-to-Commons Model of Public Support For Environmental Energy Policy
International Nuclear Information System (INIS)
Merrill, Ryan; Sintov, Nicole
2016-01-01
As atmospheric CO_2 continues to rise above 450 PPM, policymakers struggle with uncertainty concerning predictors of citizen support for environmental energy policies (EEPs) and preferences for their design, topics which have received limited attention in empirical literature. We present an original model of policy support based on citizens’ affinity-to-commons: pathways by which individuals enjoy natural public goods that in turn shape preferences between alternative policy mechanisms. We evaluate this model using a survey of southern California electricity customers, with results indicating the model's utility in predicting public support of EEP. Stronger community ties are associated with preferences for “pull”-type subsidies, whereas stronger connections to natural commons are linked to support for both “pull” and “push”-type sanctions. Findings have implications for coalition building as advocates may engender support for green energy policy by framing sanctions as protecting natural commons, and framing subsidies either in this same way and/or as producing benefits for communities. - Highlights: • A commons-oriented model of citizen support for environmental energy policy is proposed (Thaler (2012)). • A factor analysis identifies local tax shifts, green subsidies, and energy taxes (Schultz et al. (1995)). • Community connections predict support for policies with employing subsidies (Sabatier (2006)). • Connection to nature predicts support for policies using both sanctions and subsidies. (Stern et al. (1999)).
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Directory of Open Access Journals (Sweden)
2011-04-01
Full Text Available Abstract Background Glaucoma is a leading cause of avoidable blindness worldwide. Open angle glaucoma is the most common type of glaucoma. No randomised controlled trials have been conducted evaluating the effectiveness of glaucoma screening for reducing sight loss. It is unclear what the most appropriate intervention to be evaluated in any glaucoma screening trial would be. The purpose of this study was to develop the clinical components of an intervention for evaluation in a glaucoma (open angle screening trial that would be feasible and acceptable in a UK eye-care service. Methods A mixed-methods study, based on the Medical Research Council (MRC framework for complex interventions, integrating qualitative (semi-structured interviews with 46 UK eye-care providers, policy makers and health service commissioners, and quantitative (economic modelling methods. Interview data were synthesised and used to revise the screening interventions compared within an existing economic model. Results The qualitative data indicated broad based support for a glaucoma screening trial to take place in primary care, using ophthalmic trained technical assistants supported by optometry input. The precise location should be tailored to local circumstances. There was variability in opinion around the choice of screening test and target population. Integrating the interview findings with cost-effectiveness criteria reduced 189 potential components to a two test intervention including either optic nerve photography or screening mode perimetry (a measure of visual field sensitivity with or without tonometry (a measure of intraocular pressure. It would be more cost-effective, and thus acceptable in a policy context, to target screening for open angle glaucoma to those at highest risk but for both practicality and equity arguments the optimal strategy was screening a general population cohort beginning at age forty. Conclusions Interventions for screening for open angle
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A Simple Forecasting Model Linking Macroeconomic Policy to Industrial Employment Demand.
Malley, James R.; Hady, Thomas F.
A study detailed further a model linking monetary and fiscal policy to industrial employment in metropolitan and nonmetropolitan areas of four United States regions. The model was used to simulate the impacts on area and regional employment of three events in the economy: changing real gross national product (GNP) via monetary policy, holding the…
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Optimal Operational Monetary Policy Rules in an Endogenous Growth Model: a calibrated analysis
Arato, Hiroki
2009-01-01
This paper constructs an endogenous growth New Keynesian model and considers growth and welfare effect of Taylor-type (operational) monetary policy rules. The Ramsey equilibrium and optimal operational monetary policy rule is also computed. In the calibrated model, the Ramseyoptimal volatility of inflation rate is smaller than that in standard exogenous growth New Keynesian model with physical capital accumulation. Optimal operational monetary policy rule makes nominal interest rate respond s...
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Hannan, Shabab B; Dräger, Nina M; Rasse, Tobias M; Voigt, Aaron; Jahn, Thomas R
2016-04-01
Abnormal tau accumulations were observed and documented in post-mortem brains of patients affected by Alzheimer's disease (AD) long before the identification of mutations in the Microtubule-associated protein tau (MAPT) gene, encoding the tau protein, in a different neurodegenerative disease called Frontotemporal dementia and Parkinsonism linked to chromosome 17 (FTDP-17). The discovery of mutations in the MAPT gene associated with FTDP-17 highlighted that dysfunctions in tau alone are sufficient to cause neurodegeneration. Invertebrate models have been diligently utilized in investigating tauopathies, contributing to the understanding of cellular and molecular pathways involved in disease etiology. An important discovery came with the demonstration that over-expression of human tau in Drosophila leads to premature mortality and neuronal dysfunction including neurodegeneration, recapitulating some key neuropathological features of the human disease. The simplicity of handling invertebrate models combined with the availability of a diverse range of experimental resources make these models, in particular Drosophila a powerful invertebrate screening tool. Consequently, several large-scale screens have been performed using Drosophila, to identify modifiers of tau toxicity. The screens have revealed not only common cellular and molecular pathways, but in some instances the same modifier has been independently identified in two or more screens suggesting a possible role for these modifiers in regulating tau toxicity. The purpose of this review is to discuss the genetic modifier screens on tauopathies performed in Drosophila and C. elegans models, and to highlight the common cellular and molecular pathways that have emerged from these studies. Here, we summarize results of tau toxicity screens providing mechanistic insights into pathological alterations in tauopathies. Key pathways or modifiers that have been identified are associated with a broad range of processes
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Stem cells: a model for screening, discovery and development of drugs
Directory of Open Access Journals (Sweden)
Kitambi SS
2011-09-01
Full Text Available Satish Srinivas Kitambi1, Gayathri Chandrasekar21Department of Medical Biochemistry and Biophysics; 2Department of Biosciences, Karolinska Institutet, Stockholm, SwedenAbstract: The identification of normal and cancerous stem cells and the recent advances made in isolation and culture of stem cells have rapidly gained attention in the field of drug discovery and regenerative medicine. The prospect of performing screens aimed at proliferation, directed differentiation, and toxicity and efficacy studies using stem cells offers a reliable platform for the drug discovery process. Advances made in the generation of induced pluripotent stem cells from normal or diseased tissue serves as a platform to perform drug screens aimed at developing cell-based therapies against conditions like Parkinson's disease and diabetes. This review discusses the application of stem cells and cancer stem cells in drug screening and their role in complementing, reducing, and replacing animal testing. In addition to this, target identification and major advances in the field of personalized medicine using induced pluripotent cells are also discussed.Keywords: therapeutics, stem cells, cancer stem cells, screening models, drug development, high throughput screening
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International Nuclear Information System (INIS)
Kuldna, Piret; Peterson, Kaja; Kuhi-Thalfeldt, Reeli
2015-01-01
Strategic Environmental Assessment (SEA) serves as a platform for bringing together researchers, policy developers and other stakeholders to evaluate and communicate significant environmental and socio-economic effects of policies, plans and programmes. Quantitative computer models can facilitate knowledge exchange between various parties that strive to use scientific findings to guide policy-making decisions. The process of facilitating knowledge generation and exchange, i.e. knowledge brokerage, has been increasingly explored, but there is not much evidence in the literature on how knowledge brokerage activities are used in full cycles of SEAs which employ quantitative models. We report on the SEA process of the national energy plan with reflections on where and how the Long-range Energy Alternatives Planning (LEAP) model was used for knowledge brokerage on emissions modelling between researchers and policy developers. Our main suggestion is that applying a quantitative model not only in ex ante, but also ex post scenario modelling and associated impact assessment can facilitate systematic and inspiring knowledge exchange process on a policy problem and capacity building of participating actors. - Highlights: • We examine the knowledge brokering on emissions modelling between researchers and policy developers in a full cycle of SEA. • Knowledge exchange process can evolve at any modelling stage within SEA. • Ex post scenario modelling enables systematic knowledge exchange and learning on a policy problem
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Energy Technology Data Exchange (ETDEWEB)
Kuldna, Piret, E-mail: piret.kuldna@seit.ee [Stockholm Environment Institute Tallinn Centre, Lai 34, Tallinn 10133 (Estonia); Peterson, Kaja [Stockholm Environment Institute Tallinn Centre, Lai 34, Tallinn 10133 (Estonia); Kuhi-Thalfeldt, Reeli [Stockholm Environment Institute Tallinn Centre, Lai 34, Tallinn 10133 (Estonia); Tallinn University of Technology, Ehitajate tee 5, Tallinn 19086 (Estonia)
2015-09-15
Strategic Environmental Assessment (SEA) serves as a platform for bringing together researchers, policy developers and other stakeholders to evaluate and communicate significant environmental and socio-economic effects of policies, plans and programmes. Quantitative computer models can facilitate knowledge exchange between various parties that strive to use scientific findings to guide policy-making decisions. The process of facilitating knowledge generation and exchange, i.e. knowledge brokerage, has been increasingly explored, but there is not much evidence in the literature on how knowledge brokerage activities are used in full cycles of SEAs which employ quantitative models. We report on the SEA process of the national energy plan with reflections on where and how the Long-range Energy Alternatives Planning (LEAP) model was used for knowledge brokerage on emissions modelling between researchers and policy developers. Our main suggestion is that applying a quantitative model not only in ex ante, but also ex post scenario modelling and associated impact assessment can facilitate systematic and inspiring knowledge exchange process on a policy problem and capacity building of participating actors. - Highlights: • We examine the knowledge brokering on emissions modelling between researchers and policy developers in a full cycle of SEA. • Knowledge exchange process can evolve at any modelling stage within SEA. • Ex post scenario modelling enables systematic knowledge exchange and learning on a policy problem.
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Van't Hoog, Anna H; Onozaki, Ikushi; Lonnroth, Knut
2014-10-19
To inform the choice of an appropriate screening and diagnostic algorithm for tuberculosis (TB) screening initiatives in different epidemiological settings, we compare algorithms composed of currently available methods. Of twelve algorithms composed of screening for symptoms (prolonged cough or any TB symptom) and/or chest radiography abnormalities, and either sputum-smear microscopy (SSM) or Xpert MTB/RIF (XP) as confirmatory test we model algorithm outcomes and summarize the yield, number needed to screen (NNS) and positive predictive value (PPV) for different levels of TB prevalence. Screening for prolonged cough has low yield, 22% if confirmatory testing is by SSM and 32% if XP, and a high NNS, exceeding 1000 if TB prevalence is ≤0.5%. Due to low specificity the PPV of screening for any TB symptom followed by SSM is less than 50%, even if TB prevalence is 2%. CXR screening for TB abnormalities followed by XP has the highest case detection (87%) and lowest NNS, but is resource intensive. CXR as a second screen for symptom screen positives improves efficiency. The ideal algorithm does not exist. The choice will be setting specific, for which this study provides guidance. Generally an algorithm composed of CXR screening followed by confirmatory testing with XP can achieve the lowest NNS and highest PPV, and is the least amenable to setting-specific variation. However resource requirements for tests and equipment may be prohibitive in some settings and a reason to opt for symptom screening and SSM. To better inform disease control programs we need empirical data to confirm the modeled yield, cost-effectiveness studies, transmission models and a better screening test.
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Mathematical Models of the Sinusoidal Screen Family
Directory of Open Access Journals (Sweden)
Tajana Koren
2011-06-01
Full Text Available In this paper we will define a family of sinusoidal screening elements and explore the possibilities of their application in graphic arts, securities printing and design solutions in photography and typography editing. For this purpose mathematical expressions of sinusoidal families were converted into a Postscript language. The introduction of a random variable results in a countless number of various mutations which cannot be repeated without knowing the programming code itself. The use of the family of screens in protection of securities is thus of great importance. Other possible application of modulated sinusoidal screens is related to the large format color printing. This paper will test the application of sinusoidal screens in vector graphics, pixel graphics and typography. The development of parameters in the sinusoidal screen element algorithms gives new forms defined within screening cells with strict requirements of coverage implementation. Individual solutions include stochastic algorithms, as well as the autonomy of screening forms in regard to multicolor printing channels.
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Cleanliness Policy Implementation: Evaluating Retribution Model to Rise Public Satisfaction
Dailiati, Surya; Hernimawati; Prihati; Chintia Utami, Bunga
2018-05-01
This research is based on the principal issues concerning the evaluation of cleanliness retribution policy which has not been optimally be able to improve the Local Revenue of Pekanbaru City and has not improved the cleanliness of Pekanbaru City. It was estimated to be caused by the performance of Garden and Sanitation Department are not in accordance with the requirement of society of Pekanbaru City. The research method used in this study is a mixed method with sequential exploratory strategy. The data collection used are observation, interview and documentation for qualitative research as well as questionnaires for quantitative research. The collected data were analyzed with interactive model of Miles and Huberman for qualitative research and multiple regression analysis for quantitative research. The research result indicated that the model of cleanliness policy implementation that can increase of PAD Pekanbaru City and be able to improve people’s satisfaction divided into two (2) which are the evaluation model and the society satisfaction model. The evaluation model influence by criteria/variable of effectiveness, efficiency, adequacy, equity, responsiveness, and appropriateness, while the society satisfaction model influence by variables of society satisfaction, intentions, goals, plans, programs, and appropriateness of cleanliness retribution collection policy.
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Rein, David B.; Wittenborn, John S.; Zhang, Xinzhi; Hoerger, Thomas J.; Zhang, Ping; Klein, Barbara Eden Kobrin; Lee, Kris E.; Klein, Ronald; Saaddine, Jinan B.
2013-01-01
Objective To estimate the cost-effectiveness of visual acuity screening performed in primary care settings and of dilated eye evaluations performed by an eye care professional among new Medicare enrollees with no diagnosed eye disorders. Medicare currently reimburses visual acuity screening for new enrollees during their initial preventive primary care health check, but dilated eye evaluations may be a more cost-effective policy. Design Monte Carlo cost-effectiveness simulation model with a total of 50 000 simulated patients with demographic characteristics matched to persons 65 years of age in the US population. Results Compared with no screening policy, dilated eye evaluations increased quality-adjusted life-years (QALYs) by 0.008 (95% credible interval [CrI], 0.005–0.011) and increased costs by $94 (95% CrI, −$35 to $222). A visual acuity screening increased QALYs in less than 95% of the simulations (0.001 [95% CrI, −0.002 to 0.004) and increased total costs by $32 (95% CrI, −$97 to $159) per person. The incremental cost-effectiveness ratio of a visual acuity screening and an eye examination compared with no screening were $29 000 and $12 000 per QALY gained, respectively. At a willingness-to-pay value of $15 000 or more per QALY gained, a dilated eye evaluation was the policy option most likely to be cost-effective. Conclusions The currently recommended visual acuity screening showed limited efficacy and cost-effectiveness compared with no screening. In contrast, a new policy of reimbursement for Welcome to Medicare dilated eye evaluations was highly cost-effective. PMID:22232367
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COLA with scale-dependent growth: applications to screened modified gravity models
Energy Technology Data Exchange (ETDEWEB)
Winther, Hans A.; Koyama, Kazuya; Wright, Bill S. [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Burnaby Road, Portsmouth, PO1 3FX (United Kingdom); Manera, Marc [Centre for Theoretical Cosmology, Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom); Zhao, Gong-Bo, E-mail: hans.a.winther@gmail.com, E-mail: kazuya.koyama@port.ac.uk, E-mail: manera.work@gmail.com, E-mail: bill.wright@port.ac.uk, E-mail: gong-bo.Zhao@port.ac.uk [National Astronomy Observatories, Chinese Academy of Science, Beijing, 100012 (China)
2017-08-01
We present a general parallelized and easy-to-use code to perform numerical simulations of structure formation using the COLA (COmoving Lagrangian Acceleration) method for cosmological models that exhibit scale-dependent growth at the level of first and second order Lagrangian perturbation theory. For modified gravity theories we also include screening using a fast approximate method that covers all the main examples of screening mechanisms in the literature. We test the code by comparing it to full simulations of two popular modified gravity models, namely f ( R ) gravity and nDGP, and find good agreement in the modified gravity boost-factors relative to ΛCDM even when using a fairly small number of COLA time steps.
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Rein, David B.; Lesesne, Sarah B.; Smith, Bryce D.; Weinbaum, Cindy M.
2011-01-01
Objectives Information on the process and method of service delivery is sparse for hepatitis B surface antigen (HBsAg) testing, and no systematic study has evaluated the relative effectiveness or cost-effectiveness of different HBsAg screening models. To address this need, we compared five specific community-based screening programs. Methods We funded five HBsAg screening programs to collect information on their design, costs, and outcomes of participants during a six-month observation period. We categorized programs into four types of models. For each model, we calculated the number screened, the number screened as per Centers for Disease Control and Prevention (CDC) recommendations, and the cost per screening. Results The models varied by cost per person screened and total number of people screened, but they did not differ meaningfully in the proportion of people screened following CDC recommendations, the proportion of those screened who tested positive, or the proportion of those who newly tested positive. Conclusions Integrating screening into outpatient service settings is the most cost-effective method but may not reach all people needing to be screened. Future research should examine cost-effective methods that expand the reach of screening into communities in outpatient settings. PMID:21800750
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A top-down bottom-up modeling approach to climate change policy analysis
International Nuclear Information System (INIS)
Tuladhar, Sugandha D.; Yuan, Mei; Bernstein, Paul; Montgomery, W. David; Smith, Anne
2009-01-01
This paper analyzes macroeconomic impacts of U.S. climate change policies for three different emissions pathways using a top-down bottom-up integrated model. The integrated model couples a technology-rich, bottom-up model of the U.S. electricity sector with a fully dynamic, forward-looking general equilibrium model of the U.S. economy. Our model provides a unique and consistent modeling framework for climate change analysis. Because of the model's detail and flexibility, we use it to examine additional scenarios to analyze many of the major uncertainties surrounding the implementation and impact of climate change policies - the role of command-and-control measures, loss in flexibility mechanisms such as banking, limits on low-emitting technology, and availability of offsets. The results consistently demonstrate that those policies that combine market-oriented abatement incentives with full flexibility are the most cost-effective. (author)
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How much monetary policy rules do we need to estimate DSGE model for Russia?
Shulgin, Andrei
2014-01-01
This paper presents a three-sector DSGE model for a small open economy under the intermediate exchange rate regime. The central bank balance sheet equations are added to allow introducing two different monetary policy rules in the model. The principal question is how many independent monetary policy rules we need to describe Russian monetary policy in 2001–2012. To get an answer we perform Bayesian estimation of the DSGE model for four different combinations of monetary policy rules. The main...
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Quality assurance target for community-based breast cancer screening in China: a model simulation.
Yang, Lan; Wang, Jing; Cheng, Juan; Wang, Yuan; Lu, Wenli
2018-03-07
We aimed to clarify the feasibility of a community-based screening strategy for breast cancer in Tianjin, China; to identify the factors that most significantly influenced its feasibility; and to identify the reference range for quality control. A state-transition Markov model simulated a hypothetical cohort of 100,000 healthy women, the start aged was set at 35 years and the time horizon was set to 50 years. The primary outcome for the model was the incremental cost-utility ratio (ICUR), defined as the program's cost per quality-adjusted life year (QALY) gained. Three screening strategies providing by community health service for women aged 35 to 69 years was compared regarding to different intervals. The probability of the ICUR being below 20 272USD (i.e., triple the annual gross domestic product [3 GDPs]) per QALY saved was 100% for annual screening strategy and screening every three years. Only when the attendance rate was > 50%, the probability for annual screening would be cost effective > 95%. The probability for the annual screening strategy being cost effective could reach to 95% for a willingness-to-pay (WTP) of 2 GDPs when the compliance rate for transfer was > 80%. When 10% stage I tumors were detected by screening, the probability of the annual screening strategy being cost effective would be up to 95% for a WTP > 3 GDPs. Annual community-based breast cancer screening was cost effective for a WTP of 3 GDP based on the incidence of breast cancer in Tianjin, China. Measures are needed to ensure performance indicators to a desirable level for the cost-effectiveness of breast cancer screening.
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Modeling policy issues in a world of imperfect competition
DEFF Research Database (Denmark)
Dierker, Egbert; Grodal, Birgit
1998-01-01
General equilibrium theory constitutes a sound basis for the discussion of policy issues if firms do not have market power. However, if firms influence prices strategically, the concept of profits loses its meaning due to the price normalization problem. Hence, it is unclear how to model the beha......General equilibrium theory constitutes a sound basis for the discussion of policy issues if firms do not have market power. However, if firms influence prices strategically, the concept of profits loses its meaning due to the price normalization problem. Hence, it is unclear how to model...... the behavior of oligopolistic firms. In order to provide a conceptual foundation for the analysis of policy issues in the case of imperfect competition, we discuss ways to formulate the objective of a strategic firm. In particular, we investigate the concept of real wealth maximization that is based on profits...
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Large scale hydro-economic modelling for policy support
de Roo, Ad; Burek, Peter; Bouraoui, Faycal; Reynaud, Arnaud; Udias, Angel; Pistocchi, Alberto; Lanzanova, Denis; Trichakis, Ioannis; Beck, Hylke; Bernhard, Jeroen
2014-05-01
To support European Union water policy making and policy monitoring, a hydro-economic modelling environment has been developed to assess optimum combinations of water retention measures, water savings measures, and nutrient reduction measures for continental Europe. This modelling environment consists of linking the agricultural CAPRI model, the LUMP land use model, the LISFLOOD water quantity model, the EPIC water quality model, the LISQUAL combined water quantity, quality and hydro-economic model, and a multi-criteria optimisation routine. With this modelling environment, river basin scale simulations are carried out to assess the effects of water-retention measures, water-saving measures, and nutrient-reduction measures on several hydro-chemical indicators, such as the Water Exploitation Index (WEI), Nitrate and Phosphate concentrations in rivers, the 50-year return period river discharge as an indicator for flooding, and economic losses due to water scarcity for the agricultural sector, the manufacturing-industry sector, the energy-production sector and the domestic sector, as well as the economic loss due to flood damage. Recently, this model environment is being extended with a groundwater model to evaluate the effects of measures on the average groundwater table and available resources. Also, water allocation rules are addressed, while having environmental flow included as a minimum requirement for the environment. Economic functions are currently being updated as well. Recent development and examples will be shown and discussed, as well as open challenges.
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Modeling policy mix to improve the competitiveness of Indonesian palm oil industry
Energy Technology Data Exchange (ETDEWEB)
Silitonga, R. Y.H.; Siswanto, J.; Simatupang, T.; Bahagia, S.N.
2016-07-01
The purpose of this research is to develop a model that will explain the impact of government policies to the competitiveness of palm oil industry. The model involves two commodities in this industry, namely crude palm oil (CPO) and refined palm oil (RPO), each has different added value. The model built will define the behavior of government in controlling palm oil industry, and their interactions with macro-environment, in order to improve the competitiveness of the industry. Therefore the first step was to map the main activities in this industry using value chain analysis. After that a conceptual model was built, where the output of the model is competitiveness of the industry based on market share. The third step was model formulation. The model is then utilized to simulate the policy mix given by government in improving the competitiveness of Palm Oil Industry. The model was developed using only some policies which give direct impact to the competitiveness of the industry. For macro environment input, only price is considered in this model. The model can simulate the output of the industry for various government policies mix given to the industry. This research develops a model that can represent the structure and relationship between industry, government and macro environment, using value chain analysis and hierarchical multilevel system approach. (Author)
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Modeling policy mix to improve the competitiveness of Indonesian palm oil industry
Directory of Open Access Journals (Sweden)
Roland Y H Silitonga
2016-04-01
Full Text Available Purpose: The purpose of this research is to develop a model that will explain the impact of government policies to the competitiveness of palm oil industry. The model involves two commodities in this industry, namely crude palm oil (CPO and refined palm oil (RPO, each has different added value. Design/methodology/approach: The model built will define the behavior of government in controlling palm oil industry, and their interactions with macro-environment, in order to improve the competitiveness of the industry. Therefore the first step was to map the main activities in this industry using value chain analysis. After that a conceptual model was built, where the output of the model is competitiveness of the industry based on market share. The third step was model formulation. The model is then utilized to simulate the policy mix given by government in improving the competitiveness of Palm Oil Industry. Research limitations/implications: The model was developed using only some policies which give direct impact to the competitiveness of the industry. For macro environment input, only price is considered in this model. Practical implications: The model can simulate the output of the industry for various government policies mix given to the industry. Originality/value: This research develops a model that can represent the structure and relationship between industry, government and macro environment, using value chain analysis and hierarchical multilevel system approach.
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A goal programming model for environmental policy analysis: Application to Spain
International Nuclear Information System (INIS)
San Cristóbal, José Ramón
2012-01-01
Sustainable development has become an important part of international and national approaches to integrate economic, environmental, social and ethical considerations so that a good quality of life can be enjoyed by current and future generations for as long as possible. However, nowadays sustainable development is threatened by industrial pollution emissions which cause serious environmental problems. Due to a lack of adequate quantitative models for environmental policy analysis, there is a strong need for analytical models in order to know the effects of environmental policies. In the present paper, a goal programming model, based on an environmental/input–output linear programming model, is developed and applied to the Spanish economy. The model combines relations between economic, energy, social and environmental effects, providing valuable information for policy-makers in order to define and examine the different goals that must be implemented to reach sustainability. - Highlights: ► In this paper a goal programming model is developed. ► The model considers environmental, energy, social and economic goals. ► The model shows the effects of a reduction in greenhouse gasses emission and energy requirements. ► The model is applied to the Spanish economy.
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Houle, B; Siegel, M
2009-02-01
A marked shift in tobacco-related workplace health promotion intervention involves the adoption of policies barring employment to smokers. We discuss the potential public health consequences of these policies on those affected-smokers, their families, the surrounding community and society at large. We find a lack of published evidence evaluating the effectiveness and consequences of these policies. By developing a model of policy effects, we outline possible unintended consequences. With such large gaps in the evidence base and the potential for deleterious consequences, we argue for increased discussion about the use of smoker-free employment policies as a public health intervention and for increased engagement of employers by the public health community in worksite health promotion.
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Colorectal Cancer Screening: A Guide to the Guidelines
Directory of Open Access Journals (Sweden)
Douglas K Rex
1999-01-01
Full Text Available The two most recent guidelines for colorectal cancer screening are those of the Agency for Healthcare Policy and Research, and the American Cancer Society. The guidelines are similar in many regards and reflect current literature, consensus opinion and compromise between members of multidisciplinary panels. The emphasis of both guidelines is to increase the options available for colorectal cancer screening. Increasing choice should expand the attractiveness of colorectal cancer screening to more patients and physicians, and the development of guidelines should help compel payers to provide reimbursement for colorectal cancer screening. These guidelines are summarized and evaluated as they pertain to colorectal cancer screening.
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Geue, Claudia; Wu, Olivia; Xin, Yiqiao; Heggie, Robert; Hutchinson, Sharon; Martin, Natasha K.; Fenwick, Elisabeth; Goldberg, David
2015-01-01
Introduction Studies evaluating the cost-effectiveness of screening for Hepatitis B Virus (HBV) and Hepatitis C Virus (HCV) are generally heterogeneous in terms of risk groups, settings, screening intervention, outcomes and the economic modelling framework. It is therefore difficult to compare cost-effectiveness results between studies. This systematic review aims to summarise and critically assess existing economic models for HBV and HCV in order to identify the main methodological differences in modelling approaches. Methods A structured search strategy was developed and a systematic review carried out. A critical assessment of the decision-analytic models was carried out according to the guidelines and framework developed for assessment of decision-analytic models in Health Technology Assessment of health care interventions. Results The overall approach to analysing the cost-effectiveness of screening strategies was found to be broadly consistent for HBV and HCV. However, modelling parameters and related structure differed between models, producing different results. More recent publications performed better against a performance matrix, evaluating model components and methodology. Conclusion When assessing screening strategies for HBV and HCV infection, the focus should be on more recent studies, which applied the latest treatment regimes, test methods and had better and more complete data on which to base their models. In addition to parameter selection and associated assumptions, careful consideration of dynamic versus static modelling is recommended. Future research may want to focus on these methodological issues. In addition, the ability to evaluate screening strategies for multiple infectious diseases, (HCV and HIV at the same time) might prove important for decision makers. PMID:26689908
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Kim, Hyun-Duck; Sukhbaatar, Munkhzaya; Shin, Myungseop; Ahn, Yoo-Been; Yoo, Wook-Sung
2014-12-01
This study aims to evaluate and validate a periodontitis screening model that includes sociodemographic, metabolic syndrome (MetS), and molecular information, including gingival crevicular fluid (GCF), matrix metalloproteinase (MMP), and blood cytokines. The authors selected 506 participants from the Shiwha-Banwol cohort: 322 participants from the 2005 cohort for deriving the screening model and 184 participants from the 2007 cohort for its validation. Periodontitis was assessed by dentists using the community periodontal index. Interleukin (IL)-6, IL-8, and tumor necrosis factor-α in blood and MMP-8, -9, and -13 in GCF were assayed using enzyme-linked immunosorbent assay. MetS was assessed by physicians using physical examination and blood laboratory data. Information about age, sex, income, smoking, and drinking was obtained by interview. Logistic regression analysis was applied to finalize the best-fitting model and validate the model using sensitivity, specificity, and c-statistics. The derived model for periodontitis screening had a sensitivity of 0.73, specificity of 0.85, and c-statistic of 0.86 (P validated model were 0.64, 0.91, and 0.83 (P <0.001), respectively. The model that included age, sex, income, smoking, drinking, and blood and GCF biomarkers could be useful in screening for periodontitis. A future prospective study is indicated for evaluating this model's ability to predict the occurrence of periodontitis.
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Screening for psychological distress in cancer: renewing the research agenda.
Salmon, Peter; Clark, Louise; McGrath, Elly; Fisher, Peter
2015-03-01
Although health policy for cancer care promotes screening of patients for emotional distress, the utility and validity of screening have been questioned. Continued research to refine detection of distress or to evaluate outcomes of screening programmes is unlikely to end this controversy. Instead, we need to identify more fundamental research questions that address the validity or utility of screening in this context. We critically and selectively review research and policy literature on psychological screening in cancer care, drawing also from research literature about the nature of psychological needs in cancer care and from relevant literature on psychological screening in mental health. We identify three broad research questions: (i) Apart from intensity of distress, what further information should screening seek about the context of distress, psychological processes that promote distress and patients' own perspective on their needs? (ii) What are the implications of the contextual dependence of disclosure of emotional feelings, given that screening questions can be asked in contexts ranging from an impersonal questionnaire to dialogue with a trusted practitioner? (iii) How should a screen be responded to, given the inherent uncertainty associated with screening results and given that distress in a cancer context can indicate instrumental as well as psychological needs? Examining these questions will mean exchanging a diagnostic framework for screening, in which health need is indicated by the presence of a psychological disorder, for a public health framework, in which health need is identified from multiple perspectives. Copyright © 2014 John Wiley & Sons, Ltd.
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Modelling climate change policies : an application of ENERGY2020
International Nuclear Information System (INIS)
Timilsina, G.; Bhargava, A.; Backus, G.
2005-01-01
Researches and policy-makers are increasingly analyzing the economic impacts of the Kyoto Protocol at national, regional and global levels. The analyses are generally based on numerical models integrating energy, environment and the economy. Most models range from partial equilibrium types to complex multi-sector general equilibrium models, and typically represent the energy sector at an aggregate level, which limits their ability to reflect details of different sectors. In Canada, a model called ENERGY2020 has been widely used by the federal and provincial governments to analyze the sectoral and provincial impacts of implementing the Kyoto Protocol. ENERGY2020 uses stocks and flows simulation that captures the physical aspects of the processes utilizing energy, as well as the qualitative choice theory which captures human behavioural aspects. The model also has a database containing 20 years of time-series on all economic, environmental and energy variables, enabling the model to derive most parameters endogenously through econometric estimations. It has the capacity to analyze consumer and business responses over a wide range of policy initiatives such as energy environment taxes, regulatory standards for buildings, equipment and motor vehicles, grants, rebates and subsidy initiatives, consumer awareness initiatives, technology improvements, moratoriums and mandated cut-backs. It is also capable of producing long-term energy market forecasts as well as analyzing the impacts of policies in the markets. It was concluded that the model's application will serve as a useful analytical tool for a range of issues, and may be useful to developing countries and economies in transition. 6 refs., 5 figs
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Strategic environmental assessment policy integration model for solid waste management in Malaysia
International Nuclear Information System (INIS)
Victor, Dennis; Agamuthu, P.
2013-01-01
Highlights: • We identified policy drivers of SEA in solid waste policy planning. • The SEA primary policy drivers are benefits, barriers and enablers need. • The SEA sub-drivers are environmental attitude and environmental awareness. • Optimal SEA policy integration requires public participation and capacity building. • SEA integration should be a long-term sustainable policy strategy for SWM. -- Abstract: This paper examines the strategic environmental assessment (SEA) systemic policy drivers for solid waste management (SWM) policies, plans and programmes (PPP) in Malaysia. Solid waste generation in Malaysia has been increasing drastically from 9.0 million tonnes in 2000 to an expected 15.6 million tonnes in 2020. This projected rate of solid waste generation is expected to burden the country's environmental and water quality resources. The key problem the study frames is the lack of environmental integration in the SWM process which is only conducted during the environmental impact assessments (EIA) stage of SWM facilities. The purpose of this study is to expand the SEA subject knowledge by validating a behaviour based theoretical framework and identifying key policy drivers that influence the integration of SEA in SWM policy planning. The study methodology utilized a confirmatory covariance based structural equation modelling approach to validate the proposed theoretical model based on the policy makers/implementers interview questionnaire data collection. The study findings indicate five latent SEA policy drivers which were named policy knowledge, environmental attitude, perceived benefits, perceived barriers and perceived enablers. The study has conceptualized and tested a SEA policy model which indicates that SEA integration behaviour is influenced directly by three main drivers (perception of benefits, perception of barriers and perception of enablers) and influenced indirectly by two sub-drivers environmental attitude and environmental knowledge
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Nudging or education to responsible choices? The example of breast screening.
Tallacchini, Mariachiara
2017-01-01
"Nudge, or nudging, refers to a policy approach inspired by behavioral sciences: it promotes the conducts identified as desirable by regulators without applying prohibition and coercion. This approach has gained a lot of momentum in the domain of health policies. Policy strategies based on behavioral insights appear ideal as to implementing healthier life styles and public health programs while minimizing compliance costs: from organ donation to food choices, from fighting obesity and chronic diseases to screening policies. Nudging, however, is not exempt from problems, especially in the sector of health, where individual free and informed consent constitutes a founding principle. Cancer screening programs, and especially breast cancer population tests, represent an interesting example for nudging strategies which have been widely applied but have also raised serious criticisms. Despite having been widely adopted by health systems, from the United States to the European Union, breast cancer screening programs keep raising debates about their actual impact on reducing mortality, risks of overdiagnosing and unnecessary or harmful treatments. In challenging the validity of screening programs, these controversies also affect their efficacy. Nudging has therefore been seen as a potentially useful tool in increasing participation, even though the extent of its actual impact remains ambiguous and problematic. For nudging to represent a relevant, powerful policy instrument its legitimacy requirements need to be identified. These concern the "right place" of behavioral-based measures within the traditional regulatory framework. The "right place" of nudging in science-based policies is part of a broader rethinking of what is democracy in "knowledge-based societies", namely through which procedures democratic institutions validate and legitimize their normative choices depending on uncertain and controversial knowledge."
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Malugin, Vladimir; Demidenko , Mikhail; Kalechits, Dmitry; Miksjuk , Alexei; Tsukarev , Taras
2009-01-01
A system of econometric models designed for forecasting target monetary indicators as well as conducting monetary policy scenarios analysis is presented. The econometric models integrated in the system are represented in the error correction form and are interlinked by means of monetary policy instruments variables, common exogenous variables characterizing external shocks, and monetary policy target endogenous variables. Forecast accuracy estimates and monetary policy analysis results are pr...
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Long term modelling in a second rank world: application to climate policies
International Nuclear Information System (INIS)
Crassous, R.
2008-11-01
This research aims at the identification of the dissatisfaction reasons with respect to the existing climate models, at the design of an innovating modelling architecture which would respond to these dissatisfactions, and at proposing climate policy assessment pathways. The authors gives a critique assessment of the modelling activity within the field of climate policies, outlines the fact that the large number and the scattering of existing long term scenarios hides a weak control of uncertainties and of the inner consistency of the produced paths, as well as the very low number of modelling paradigms. After a deepened analysis of modelling practices, the author presents the IMACLIM-R modelling architecture which is presented on a world scale and includes 12 areas and 12 sectors, and allows the simulation of evolutions by 2050, and even 2100, with a one-year time step. The author describes a scenario without any climate policy, highlights reassessment possibilities for economical trajectories which would allow greenhouse gas concentration stabilisation on a long term basis through the application of IMACLIM-R innovations. He outlines adjustment and refinement possibilities for climate policies which would robustly limit the transition cost risks
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Pennsylvania's experience in mass screening
International Nuclear Information System (INIS)
Gerusky, T.M.
1975-01-01
A policy statement issued in 1972 by the Assistant Secretary for Health and Scientific Affairs of the Department of Health, Education, and Welfare recommended that community chest x-ray surveys should not be used as a screening procedure for the detection of cardiopulmonary disorders and that when chest x-ray screening programs are justified for selected population groups, the full size photograph, rather than the miniature film, is preferred. A survey conducted in 1974--75 revealed that chest x rays were required for prisoners, prison employees, school employees, food handlers, and students who wished to participate in sports. Meetings were held with medical associations in the hope of stopping the local mass-screening operations. Of 27 groups in Pennsylvania involved in tuberculosis screening, 12 groups refused or were unwilling to phase out their photofluorographic procedures. The problem will be resolved by regulation
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A comparison of scoring models for computerised mental health screening for federal prison inmates.
Martin, Michael S; Wamboldt, Ashley D; O'Connor, Shannon L; Fortier, Julie; Simpson, Alexander I F
2013-02-01
There are high rates of mental disorder in correctional environments, so effective mental health screening is needed. Implementation of the computerised mental health screen of the Correctional Service of Canada has led to improved identification of offenders with mental health needs but with high rates of false positives. The goal of this study is to evaluate the use of an iterative classification tree (ICT) approach to mental health screening compared with a simple binary approach using cut-off scores on screening tools. A total of 504 consecutive admissions to federal prison completed the screen and were also interviewed by a mental health professional. Relationships between screening results and more extended assessment and clinical team discussion were tested. The ICT was more parsimonious in identifying probable 'cases' than standard binary screening. ICT was also highly accurate at detecting mental health needs (AUC=0.87, 95% CI 0.84-0.90). The model identified 118 (23.4%) offenders as likely to need further assessment or treatment, 87% of whom were confirmed cases at clinical interview. Of the 244 (48.4%) offenders who were screened out, only 9% were clinically assessed as requiring further assessment or treatment. Standard binary screening was characterised by more false positives and a comparable false negative rate. The use of ICTs to interpret screening data on the mental health of prisoners needs further evaluation in independent samples in Canada and elsewhere. This first evaluation of the application of such an approach offers the prospect of more effective and efficient use of the scarce resource of mental health services in prisons. Although not required, the use of computers can increase the ease of implementing an ICT model. Copyright © 2013 John Wiley & Sons, Ltd.
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Cost-effectiveness of community screening for glaucoma in rural India: a decision analytical model.
John, D; Parikh, R
2018-02-01
Studies in several countries have demonstrated the cost-effectiveness of population-based screening for glaucoma when targeted at high-risk groups such as older adults and with familial history of disease. This study conducts a cost-effective analysis of a hypothetical community screening and subsequent treatment programme in comparison to opportunistic case finding for glaucoma in rural India. A hypothetical screening programme for both primary open-angle glaucoma and angle-closure disease was built for a population aged between 40 and 69 years in rural areas of India. A decision analytical model was built to model events, costs and treatment pathways with and without a hypothetical screening programme for glaucoma for a rural-based population aged between 40 and 69 years in India. The treatment pathway included both primary open-angle glaucoma and angle-closure disease. The data on costs of screening and treatment were provided by an administrator of a tertiary eye hospital in Eastern India. The probabilities for the screening and treatment pathway were derived from published literature and a glaucoma specialist. The glaucoma prevalence rates were adapted from the Chennai Glaucoma Study findings. An incremental cost-effectiveness ratio value of ₹7292.30 per quality-adjusted life-year was calculated for a community-screening programme for glaucoma in rural India. The community screening for glaucoma would treat an additional 2872 cases and prevent 2190 person-years of blindness over a 10-year period. Community screening for glaucoma in rural India appears to be cost-effective when judged by a ratio of willingness-to-pay thresholds as per WHO-CHOICE guidelines. For community screening to be cost-effective, adequate resources, such as trained medical personnel and equipment would need to be made available. Copyright © 2017 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.
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Maire, Sophie
2016-01-01
Energy policy needs to rely on the proper understanding of the interactions between policy instruments, consumer preferences, investment behavior, market structure, electricity supply, and the wider policy environment. This asks for appropriate modeling tools, able to represent precisely electricity supply options, model all types of energy and climate policies, as well as the reactions of the rest of the economy. Chapter 2 describes the ELECTRA-CH framework, developed to analyze electrici...
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Comparing deep learning models for population screening using chest radiography
Sivaramakrishnan, R.; Antani, Sameer; Candemir, Sema; Xue, Zhiyun; Abuya, Joseph; Kohli, Marc; Alderson, Philip; Thoma, George
2018-02-01
According to the World Health Organization (WHO), tuberculosis (TB) remains the most deadly infectious disease in the world. In a 2015 global annual TB report, 1.5 million TB related deaths were reported. The conditions worsened in 2016 with 1.7 million reported deaths and more than 10 million people infected with the disease. Analysis of frontal chest X-rays (CXR) is one of the most popular methods for initial TB screening, however, the method is impacted by the lack of experts for screening chest radiographs. Computer-aided diagnosis (CADx) tools have gained significance because they reduce the human burden in screening and diagnosis, particularly in countries that lack substantial radiology services. State-of-the-art CADx software typically is based on machine learning (ML) approaches that use hand-engineered features, demanding expertise in analyzing the input variances and accounting for the changes in size, background, angle, and position of the region of interest (ROI) on the underlying medical imagery. More automatic Deep Learning (DL) tools have demonstrated promising results in a wide range of ML applications. Convolutional Neural Networks (CNN), a class of DL models, have gained research prominence in image classification, detection, and localization tasks because they are highly scalable and deliver superior results with end-to-end feature extraction and classification. In this study, we evaluated the performance of CNN based DL models for population screening using frontal CXRs. The results demonstrate that pre-trained CNNs are a promising feature extracting tool for medical imagery including the automated diagnosis of TB from chest radiographs but emphasize the importance of large data sets for the most accurate classification.
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Tukey, Melissa H; Clark, Jack A; Bolton, Rendelle; Kelley, Michael J; Slatore, Christopher G; Au, David H; Wiener, Renda Soylemez
2016-10-01
To mitigate the potential harms of screening, professional societies recommend that lung cancer screening be conducted in multidisciplinary programs with the capacity to provide comprehensive care, from screening through pulmonary nodule evaluation to treatment of screen-detected cancers. The degree to which this standard can be met at the national level is unknown. To assess the readiness of clinical facilities in a national healthcare system for implementation of comprehensive lung cancer screening programs, as compared with the ideal described in policy recommendations. This was a cross-sectional, self-administered survey of staff pulmonologists in pulmonary outpatient clinics in Veterans Health Administration facilities. The facility-level response rate was 84.1% (106 of 126 facilities with pulmonary clinics); 88.7% of facilities showed favorable provider perceptions of the evidence for lung cancer screening, and 73.6% of facilities had a favorable provider-perceived local context for screening implementation. All elements of the policy-recommended infrastructure for comprehensive screening programs were present in 36 of 106 facilities (34.0%); the most common deficiencies were the lack of on-site positron emission tomography scanners or radiation oncology services. Overall, 26.5% of Veterans Health Administration facilities were ideally prepared for lung cancer screening implementation (44.1% if the policy recommendations for on-site positron emission tomography scanners and radiation oncology services were waived). Many facilities may be less than ideally positioned for the implementation of comprehensive lung cancer screening programs. To ensure safe, effective screening, hospitals may need to invest resources or coordinate care with facilities that can offer comprehensive care for screening through downstream evaluation and treatment of screen-detected cancers.
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Lew, Jie-Bin; St John, D James B; Xu, Xiang-Ming; Greuter, Marjolein J E; Caruana, Michael; Cenin, Dayna R; He, Emily; Saville, Marion; Grogan, Paul; Coupé, Veerle M H; Canfell, Karen
2017-07-01
No assessment of the National Bowel Screening Program (NBCSP) in Australia, which considers all downstream benefits, costs, and harms, has been done. We aimed to use a comprehensive natural history model and the most recent information about cancer treatment costs to estimate long-term benefits, costs, and harms of the NBCSP (2 yearly immunochemical faecal occult blood testing screening at age 50-74 years) and evaluate the incremental effect of improved screening participation under different scenarios. In this modelling study, a microsimulation model, Policy1-Bowel, which simulates the development of colorectal cancer via both the conventional adenoma-carcinoma and serrated pathways was used to simulate the NBCSP in 2006-40, taking into account the gradual rollout of NBCSP in 2006-20. The base-case scenario assumed 40% screening participation (currently observed behaviour) and two alternative scenarios assuming 50% and 60% participation by 2020 were modelled. Aggregate year-by-year screening, diagnosis, treatment and surveillance-related costs, resource utilisation (number of screening tests and colonoscopies), and health outcomes (incident colorectal cancer cases and colorectal cancer deaths) were estimated, as was the cost-effectiveness of the NBCSP. With current levels of participation (40%), the NBCSP is expected to prevent 92 200 cancer cases and 59 000 deaths over the period 2015-40; an additional 24 300 and 37 300 cases and 16 800 and 24 800 deaths would be prevented if participation was increased to 50% and 60%, respectively. In 2020, an estimated 101 000 programme-related colonoscopies will be done, associated with about 270 adverse events; an additional 32 500 and 49 800 colonoscopies and 88 and 134 adverse events would occur if participation was increased to 50% and 60%, respectively. The overall number needed to screen (NNS) is 647-788 per death prevented, with 52-59 colonoscopies per death prevented. The programme is cost
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Sekiguchi, Masau; Kakugawa, Yasuo; Matsumoto, Minori; Matsuda, Takahisa
2018-01-22
Risk stratification of screened populations could help improve colorectal cancer (CRC) screening. Use of the modified Asia-Pacific Colorectal Screening (APCS) score has been proposed in the Asia-Pacific region. This study was performed to build a new useful scoring model for CRC screening. Data were reviewed from 5218 asymptomatic Japanese individuals who underwent their first screening colonoscopy. Multivariate logistic regression was used to investigate risk factors for advanced colorectal neoplasia (ACN), and a new scoring model for the prediction of ACN was developed based on the results. The discriminatory capability of the new model and the modified APCS score were assessed and compared. Internal validation was also performed. ACN was detected in 225 participants. An 8-point scoring model for the prediction of ACN was developed using five independent risk factors for ACN (male sex, higher age, presence of two or more first-degree relatives with CRC, body mass index of > 22.5 kg/m 2 , and smoking history of > 18.5 pack-years). The prevalence of ACN was 1.6% (34/2172), 5.3% (127/2419), and 10.2% (64/627) in participants with scores of statistic of the scoring model was 0.70 (95% confidence interval, 0.67-0.73) in both the development and internal validation sets, and this value was higher than that of the modified APCS score [0.68 (95% confidence interval, 0.65-0.71), P = 0.03]. We built a new simple scoring model for prediction of ACN in a Japanese population that could stratify the screened population into low-, moderate-, and high-risk groups.
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Directory of Open Access Journals (Sweden)
Singa Wang Chiu
2018-09-01
Full Text Available This study employs mathematical modeling to explore the effects of overtime option, rework, and discontinuous end-item issuing policy on the economic manufacturing quantity (EMQ model. Conventional EMQ model assumed that all products fabricated are of good quality and are issued under continuous policy. In real world, however, nonconforming items are randomly produced, due to diverse unexpected factors in fabrication process. When finished items are to be distributed to outside locations, discontinuous multi-shipment policy is often used rather than continuous rule. In addition, with the intention of increasing short-term capacity or shortening replenishment cycle length to smooth the production planning, adopting overtime option can be an effective strategy. To cope with the aforementioned features in real production systems, this study incorporates overtime option, rework, and multi-shipment policy into the EMQ model and explores their joint effects on optimal lot size and number of shipments, and on other relevant system parameters. Mathematical modeling and Hessian matrix equations enable us to derive the optimal policies to the problem. Through the use of numerical example, the applicability of research result is exhibited and a variety of significant effects of these features on the proposed system are revealed.
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Creation of a National, At-home Model for Ashkenazi Jewish Carrier Screening.
Grinzaid, Karen Arnovitz; Page, Patricia Zartman; Denton, Jessica Johnson; Ginsberg, Jessica
2015-06-01
Ethnicity-based carrier screening for the Ashkenazi Jewish population has been available and encouraged by advocacy and community groups since the early 1970's. Both the American College of Medical Genetics and the American Congress of Obstetricians and Gynecologists recommend carrier screening for this population (Obstetrics and Gynecology, 114(4), 950-953, 2009; Genetics in Medicine, 10(1), 55-56, 2008). While many physicians inquire about ethnic background and offer appropriate carrier screening, studies show that a gap remains in implementing recommendations (Genetic testing and molecular biomarkers, 2011). In addition, education and outreach efforts targeting Jewish communities have had limited success in reaching this at-risk population. Despite efforts by the medical and Jewish communities, many Jews of reproductive age are not aware of screening, and remain at risk for having children with preventable diseases. Reaching this population, preferably pre-conception, and facilitating access to screening is critically important. To address this need, genetic counselors at Emory University developed JScreen, a national Jewish genetic disease screening program. The program includes a national marketing and PR campaign, online education, at-home saliva-based screening, post-test genetic counseling via telephone or secure video conferencing, and referrals for face-to-face genetic counseling as needed. Our goals are to create a successful education and screening program for this population and to develop a model that could potentially be used for other at-risk populations.
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Ensuring Integrity in AGU Publications and Compliance With Dual Publication Policy
Kumar, Praveen; Calais, Eric
2011-03-01
To ensure the highest standards for publication, AGU has begun screening manuscript submissions using CrossCheck (http://www.crossref.org/crosscheck.html) for possible verbatim use of previously published material. Water Resources Research and Geophysical Research Letters have tested this technology since summer 2010. It has proven very useful in ensuring the highest integrity in publication standards and compliance with the AGU dual publication policy (http://www.agu.org/pubs/authors/policies/dualpub_policy.shtml). According to Barbara Major, assistant director of journals, other AGU journals will adopt this screening process in the near future.
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van Hees, Frank; Zauber, Ann G.; van Veldhuizen, Harriët; Heijnen, Marie-Louise A.; Penning, Corine; de Koning, Harry J.; van Ballegooijen, Marjolein; Lansdorp-Vogelaar, Iris
2015-01-01
In May 2011, the Dutch government decided to implement a national programme for colorectal cancer (CRC) screening using biennial faecal immunochemical test (FIT) screening between ages 55 and 75.[1] Decision modelling played an important role in informing this decision, as well as in the planning and implementation of the programme afterwards. In this overview, we illustrate the value of models in informing resource allocation in CRC screening, using the role that decision modelling has played in the Dutch CRC screening programme as an example. PMID:26063755
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Model-Driven Policy Framework for Data Centers
DEFF Research Database (Denmark)
Caba, Cosmin Marius; Kentis, Angelos Mimidis; Soler, José
2016-01-01
. Moreover, the lack of simple solutions for managing the configuration and behavior of the DC components makes the DC hard to configure and slow in adapting to changes in business needs. In this paper, we propose a model-driven framework for policy-based management for DCs, to simplify not only the service...
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Energy Technology Data Exchange (ETDEWEB)
Mundaca, Luis; Neij, Lena
2009-10-15
Using the residential sector as a case study, the research presented in this report is separated into five main parts: (1) review of bottom-up methodologies and corresponding energy-economy models; (2) key drivers of energy demand and end-use coverage, (3) choice-determinants for efficient-technologies embedded in modelling methodologies; and (4) the analysis of modelling studies that focus on ex-ante energy efficiency policy evaluation. Based on the findings, (5) several research areas to further advance models are identified and discussed. We first identify four types of methodological categories: simulation, optimisation, accounting and hybrid models. A representative sample of these various methodological categories is reviewed. Technology representation is mostly explicit and technologically rich across all the reviewed models. This is a critical requisite for simulating energy efficiency policy instruments or portfolios that aim to induce ample technological change. Regardless the methodological approach, the explicit and rich technological component allows coverage of numerous energy services. All the reviewed models originate from the OECD region and more than 60 per cent of the identified applications focus mostly on developed countries. To some extent, this finding correlates with the claims about the need for more policy evaluation efforts to assist energy efficiency policy and other GHG mitigation options for the building sector in developing countries. We find that whereas capital and operating costs are relevant for efficient-technology (non-)adoption, they represent only a part of a great variety of determinants that drives consumer's energy-related decisions regarding technology choices. Factors including design, comfort, brand, functionality, reliability, environmental awareness, among others, are likely to influence the decisions of consumers in reality. Whereas economic variables are used as key determinants for technology choice in energy
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Systematic health screening of refugees after resettlement in recipient countries: a scoping review.
Hvass, Anne Mette Fløe; Wejse, Christian
2017-08-01
Health screening of refugees after settlement in a recipient country is an important tool to find and treat diseases. Currently, there are no available reviews on refugee health screening after resettlement. A systematic literature search was conducted using the online Medical Literature Analysis and Retrieval System ('MEDLINE') database. Data extraction and synthesis were performed according to the PRISMA statement. The search retrieved 342 articles. Relevance screening was conducted on all abstracts/titles. The final 53 studies included only original scientific articles on health screening of refugees conducted after settlement in another country. The 53 studies were all from North America, Australia/New Zealand and Europe. Because of differences in country policies, the screenings were conducted differently in the various locations. The studies demonstrated great variation in who was targeted for screening and how screening was conducted. The disease most frequently screened for was tuberculosis; this was done in approximately half of the studies. Few studies included screening for mental health and non-infectious diseases like diabetes and hypertension. Health screening of refugees after resettlement is conducted according to varying local policies and there are vast differences in which health conditions are covered in the screening and whom the screening is available to.
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Modeling investment uncertainty in the costs of global CO2 emission policy
International Nuclear Information System (INIS)
Birge, J.R.; Rosa, C.H.
1995-01-01
This paper investigates the effect that explicit modeling of stochastic returns to investment has on the CO 2 abatement policy returned by a large scale macroeconomic model of the United States economy. It was found that a policy derived from the mean value deterministic model in which the random variables of the stochastic model have been replaced by their expected value poorly approximates the optimal policy returned by solving the stochastic programming model. This nonoptimality is measured by determining the value of the stochastic solution and investigating the different evolutionary paths that various macroeconomic variables follow. Macroeconomic variables which stray far from their optimal paths when derived under the assumption of a certain mean valued future are as follows: the level of carbon taxation, investment in new energy production technologies, exploration for nonrenewable resources and investment in improved macroeconomic efficiency. 18 refs., 17 figs., 6 tabs
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Digital terrain modelling development and applications in a policy support environment
Peckham, Robert Joseph
2007-01-01
This publication is the first book on the development and application of digital terrain modelling for regional planning and policy support. It is a compilation of research results by international research groups at the European Commission's Joint Research Centre providing scientific support to the development and implementation of EU environmental policy. Applications include the pan-European River and Catchment Database, European Flood Alert System, European Digital Soil Database and alternative solar energy resources, all discussed in a GIS framework in the context of the INfrastructure for SPatial InfoRmation in Europe (INSPIRE). This practice-oriented book is recommended to practicing environmental modellers and GIS experts working on regional planning and policy support applications.
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Nie, Jing-Bao
2014-07-01
The Chinese Communist Party government has been forcefully promoting its jihua shengyu (planned fertility) program, known as the "one-child policy," for more than three decades. A distinctive authoritarian model of population governance has been developed. A pertinent question to be asked is whether China's one-child policy and the authoritarian model of population governance have a future. The answer must be no; they do not. Although there are many demographic, economic, and social rationales for terminating the one-child policy, the most fundamental reason for opposing its continuation is drawn from ethics. The key ethical rationale offered for the policy is that it promotes the common social good, not only for China and the Chinese people but for the whole human family. The major irony associated with this apparently convincing justification is that, although designed to improve living standards and help relieve poverty and underdevelopment, the one-child policy and the application of the authoritarian model have instead caused massive suffering to Chinese people, especially women, and made them victims of state violence. A lesson from China--one learned at the cost of individual and social suffering on an enormous scale--is that an essential prerequisite for the pursuit of the common good is the creation of adequate constraints on state power.
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Zee, van der F.A.
1997-01-01
This study explores the relevance and applicability of political economy models for the explanation of agricultural policies. Part I (chapters 4-7) takes a general perspective and evaluates the empirical applicability of voting models and interest group models to agricultural policy
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Collins, Marissa; Mason, Helen; O'Flaherty, Martin; Guzman-Castillo, Maria; Critchley, Julia; Capewell, Simon
2014-07-01
Dietary salt intake has been causally linked to high blood pressure and increased risk of cardiovascular events. Cardiovascular disease causes approximately 35% of total UK deaths, at an estimated annual cost of £30 billion. The World Health Organization and the National Institute for Health and Care Excellence have recommended a reduction in the intake of salt in people's diets. This study evaluated the cost-effectiveness of four population health policies to reduce dietary salt intake on an English population to prevent coronary heart disease (CHD). The validated IMPACT CHD model was used to quantify and compare four policies: 1) Change4Life health promotion campaign, 2) front-of-pack traffic light labeling to display salt content, 3) Food Standards Agency working with the food industry to reduce salt (voluntary), and 4) mandatory reformulation to reduce salt in processed foods. The effectiveness of these policies in reducing salt intake, and hence blood pressure, was determined by systematic literature review. The model calculated the reduction in mortality associated with each policy, quantified as life-years gained over 10 years. Policy costs were calculated using evidence from published sources. Health care costs for specific CHD patient groups were estimated. Costs were compared against a "do nothing" baseline. All policies resulted in a life-year gain over the baseline. Change4life and labeling each gained approximately 1960 life-years, voluntary reformulation 14,560 life-years, and mandatory reformulation 19,320 life-years. Each policy appeared cost saving, with mandatory reformulation offering the largest cost saving, more than £660 million. All policies to reduce dietary salt intake could gain life-years and reduce health care expenditure on coronary heart disease. Copyright © 2014 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.
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Risk assessment and remedial policy evaluation using predictive modeling
International Nuclear Information System (INIS)
Linkov, L.; Schell, W.R.
1996-01-01
As a result of nuclear industry operation and accidents, large areas of natural ecosystems have been contaminated by radionuclides and toxic metals. Extensive societal pressure has been exerted to decrease the radiation dose to the population and to the environment. Thus, in making abatement and remediation policy decisions, not only economic costs but also human and environmental risk assessments are desired. This paper introduces a general framework for risk assessment and remedial policy evaluation using predictive modeling. Ecological risk assessment requires evaluation of the radionuclide distribution in ecosystems. The FORESTPATH model is used for predicting the radionuclide fate in forest compartments after deposition as well as for evaluating the efficiency of remedial policies. Time of intervention and radionuclide deposition profile was predicted as being crucial for the remediation efficiency. Risk assessment conducted for a critical group of forest users in Belarus shows that consumption of forest products (berries and mushrooms) leads to about 0.004% risk of a fatal cancer annually. Cost-benefit analysis for forest cleanup suggests that complete removal of organic layer is too expensive for application in Belarus and a better methodology is required. In conclusion, FORESTPATH modeling framework could have wide applications in environmental remediation of radionuclides and toxic metals as well as in dose reconstruction and, risk-assessment
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Impact of a new national screening policy for Down's syndrome in Denmark
DEFF Research Database (Denmark)
Ekelund, Charlotte K; Jørgensen, Finn Stener; Petersen, Olav Bjørn
2008-01-01
OBJECTIVES: To evaluate the impact of a screening strategy in the first trimester, introduced in Denmark during 2004-6, on the number of infants born with Down's syndrome and the number of chorionic villus samplings and amniocenteses, and to determine detection and false positive rates...... and newborn infants with Down's syndrome diagnosed prenatally and postnatally and number of chorionic villus samplings and amniocenteses carried out. Secondary outcomes measured were number of women screened in 2005 and 2006, screen positive rate, and information on screening in 2005 and 2006 for infants...... with a postnatal diagnosis of Down's syndrome. RESULTS: The number of infants born with Down's syndrome decreased from 55-65 per year during 2000-4 to 31 in 2005 and 32 in 2006. The total number of chorionic villus samplings and amniocenteses carried out decreased from 7524 in 2000 to 3510 in 2006. The detection...
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Generic Screening Models for Assessing Exposures to the Public and ICRP Reference Animals and Plants
Energy Technology Data Exchange (ETDEWEB)
Yankovich, Tamara L.; Proehl, Gerhard; Telleria, Diego [International Atomic Energy Agency, P.O. Box 100, 1400 Vienna (Austria); Berkovskyy, Volodymyr [Ukrainian Radiation Protection Institute (RPI), 53, Melnikova Street, 04050, Kiev (Ukraine)
2014-07-01
With the update of the IAEA Fundamental Safety Principles (SF-1) stating the objective to protect people and the environment from harmful effects of ionizing radiation, it has been necessary to update International Basic Safety Standards (BSS) on Radiation Protection and Safety of Radiation Sources and the underlying safety guides and technical documents to provide guidance on how this could be achieved in practice. The current paper provides an update on the status and plans to revise the IAEA Safety Report 'Generic Models for Use in Assessing the Impact of Discharges of Radioactive Substances to the Environment' (SRS 19) that was published in 2001. The models of SRS 19 (2001), which was focused on assessment of exposures to the public, is being expanded into three volumes that provide methodologies for screening assessments for the public, as well as for flora and fauna. The revised SRS 19 guide will ultimately facilitate the application of screening models for different levels of assessment using updated parameter values from database that have been developed as part of the IAEA's EMRAS (Environmental Modelling for Radiation Safety) and EMRAS II international model validation programmes. The scope of the revised SRS 19 covers prospective screening assessment of doses to the representative person and Reference Animals and Plants (RAPs), and will provide simple and robust assessment methods for radiological assessment related to planning and design, applying a graded approach. Tabulated screening coefficients and environmental dilution factors will be included for 825 radionuclides. The screening coefficients are developed assuming equilibrium conditions; they can be used to assess radiological impacts arising from routine discharges of radionuclides to terrestrial and aquatic receptors for planned exposure situations. Volumes 1 and 2 of the revised SRS 19 are at an advanced stage of completion and are focused on 'Screening Assessment of Public
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Directory of Open Access Journals (Sweden)
Ulph Fiona
2007-12-01
Full Text Available Abstract Background Universal newborn screening for early detection of children affected by sickle cell disorders and cystic fibrosis is currently being implemented across England. Parents of infants identified as carriers of these disorders must also be informed of their baby's result. However there is a lack of evidence for most effective practice internationally when doing so. This study describes current or proposed models for imparting this information in practice and explores associated challenges for policy. Methods Thematic analysis of semi-structured interviews with Child Health Coordinators from all English Health Regions. Results Diverse methods for imparting carrier results, both within and between regions, and within and between conditions, were being implemented or planned. Models ranged from result by letter to in-person communication during a home visit. Non-specialists were considered the best placed professionals to give results and a similar approach for both conditions was emphasised. While national guidance has influenced choice of models, other factors contributed such as existing service structures and lack of funding. Challenges included uncertainty about guidance specifying face to face notification; how best to balance allaying parental anxiety by using familiar non-specialist health professionals with concerns about practitioner competence; and extent of information parents should be given. Inadequate consideration of resource and service workload was seen as the main policy obstacle. Clarification of existing guidance; more specific protocols to ensure consistent countrywide practice; integration of the two programmes; and 'normalising' carrier status were suggested as improvements. Conclusion Differing models for communicating carrier results raise concerns about equity and clinical governance. However, this variation provides opportunity for evaluation. Timely and more detailed guidance on protocols with
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Kumar, A M V; Satyanarayana, S; Wilson, N C; Chadha, S S; Gupta, D; Nair, S; Zachariah, R; Kapur, A; Harries, A D
2014-06-21
In 2011, bi-directional screening for tuberculosis (TB) and diabetes mellitus (DM) was recommended by the World Health Organization (WHO), although how best to implement the activity was not clear. In India, with early engagement of national programme managers and all important stakeholders, a countrywide, multicentre operational research (OR) project was designed in October 2011 and completed in 2012. The results led to a rapid national policy decision to routinely screen all TB patients for DM in September 2012. The process, experience and enablers of implementing this unique and successful collaborative model of operational research are presented.
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McLeroy, Kenneth R.
The screening of workers for health problems has been ubiquitous in the worksite for many years. These screening procedures may have ethical and policy implications. Three common types of screening in use include pre-employment, early identification of health problems, and employee monitoring. Pre-employment screening may be used to screen out…
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Replenishment policy for an inventory model under inflation
Singh, Vikramjeet; Saxena, Seema; Singh, Pushpinder; Mishra, Nitin Kumar
2017-07-01
The purpose of replenishment is to keep the flow of inventory in the system. To determine an optimal replenishment policy is a great challenge in developing an inventory model. Inflation is defined as the rate at which the prices of goods and services are rising over a time period. The cost parameters are affected by the rate of inflation. High rate of inflation affects the organizations financial conditions. Based on the above backdrop the present paper proposes the retailers replenishment policy for deteriorating items with different cycle lengths under inflation. The shortages are partially backlogged. At last numerical examples validate the results.
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Lead-Time Models Should Not Be Used to Estimate Overdiagnosis in Cancer Screening
DEFF Research Database (Denmark)
Zahl, Per-Henrik; Jørgensen, Karsten Juhl; Gøtzsche, Peter C
2014-01-01
screening--the excess-incidence approach and the lead-time approach--that rely on two different lead-time definitions. Overdiagnosis when screening with mammography has varied from 0 to 75 %. We have explained that these differences are mainly caused by using different definitions and methods......Lead-time can mean two different things: Clinical lead-time is the lead-time for clinically relevant tumors; that is, those that are not overdiagnosed. Model-based lead-time is a theoretical construct where the time when the tumor would have caused symptoms is not limited by the person's death....... It is the average time at which the diagnosis is brought forward for both clinically relevant and overdiagnosed cancers. When screening for breast cancer, clinical lead-time is about 1 year, while model-based lead-time varies from 2 to 7 years. There are two different methods to calculate overdiagnosis in cancer...
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Freshwater Ecosystem Services in Mining Regions: Modelling Options for Policy Development Support
Directory of Open Access Journals (Sweden)
Daniel Mercado-Garcia
2018-04-01
Full Text Available The ecosystem services (ES approach offers an integrated perspective of social-ecological systems, suitable for holistic assessments of mining impacts. Yet for ES models to be policy-relevant, methodological consensus in mining contexts is needed. We review articles assessing ES in mining areas focusing on freshwater components and policy support potential. Twenty-six articles were analysed concerning (i methodological complexity (data types, number of parameters, processes and ecosystem–human integration level and (ii potential applicability for policy development (communication of uncertainties, scenario simulation, stakeholder participation and management recommendations. Articles illustrate mining impacts on ES through valuation exercises mostly. However, the lack of ground- and surface-water measurements, as well as insufficient representation of the connectivity among soil, water and humans, leave room for improvements. Inclusion of mining-specific environmental stressors models, increasing resolution of topographies, determination of baseline ES patterns and inclusion of multi-stakeholder perspectives are advantageous for policy support. We argue that achieving more holistic assessments exhorts practitioners to aim for high social-ecological connectivity using mechanistic models where possible and using inductive methods only where necessary. Due to data constraints, cause–effect networks might be the most feasible and best solution. Thus, a policy-oriented framework is proposed, in which data science is directed to environmental modelling for analysis of mining impacts on water ES.
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Drug Policy: the "Dutch Model"
van Ooijen-Houben, M.M.J.; Kleemans, E.R.
2015-01-01
Dutch drug policy, once considered pragmatic and lenient and rooted in a generally tolerant attitude toward drug use, has slowly but surely shifted from a primarily public health focus to an increasing focus on law enforcement. The "coffee shop" policy and the policy toward MDMA/ecstasy are
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The social and political lives of zoonotic disease models: narratives, science and policy.
Leach, Melissa; Scoones, Ian
2013-07-01
Zoonotic diseases currently pose both major health threats and complex scientific and policy challenges, to which modelling is increasingly called to respond. In this article we argue that the challenges are best met by combining multiple models and modelling approaches that elucidate the various epidemiological, ecological and social processes at work. These models should not be understood as neutral science informing policy in a linear manner, but as having social and political lives: social, cultural and political norms and values that shape their development and which they carry and project. We develop and illustrate this argument in relation to the cases of H5N1 avian influenza and Ebola, exploring for each the range of modelling approaches deployed and the ways they have been co-constructed with a particular politics of policy. Addressing the complex, uncertain dynamics of zoonotic disease requires such social and political lives to be made explicit in approaches that aim at triangulation rather than integration, and plural and conditional rather than singular forms of policy advice. Copyright © 2013 Elsevier Ltd. All rights reserved.
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Facilitators and barriers to screening for child abuse in the emergency department
Directory of Open Access Journals (Sweden)
Louwers Eveline CFM
2012-10-01
Full Text Available Abstract Background To identify facilitators of, and barriers to, screening for child abuse in emergency departments (ED through interviews with ED staff, members of the hospital Board, and related experts. Methods This qualitative study is based on semi-structured interviews with 27 professionals from seven Dutch hospitals (i.e. seven pediatricians, two surgeons, six ED nurses, six ED managers and six hospital Board members. The resulting list of facilitators/barriers was subsequently discussed with five experts in child abuse and one implementation expert. The results are ordered using the Child Abuse Framework of the Dutch Health Care Inspectorate that legally requires screening for child abuse. Results Lack of knowledge of child abuse, communication with parents in the case of suspected abuse, and lack of time for development of policy and cases are barriers for ED staff to screen for child abuse. For Board members, lack of means and time, and a high turnover of ED staff are impediments to improving their child abuse policy. Screening can be promoted by training ED staff to better recognize child abuse, improving communication skills, appointing an attendant specifically for child abuse, explicit support of the screening policy by management, and by national implementation of an approved protocol and validated screening instrument. Conclusions ED staff are motivated to work according to the Dutch Health Care Inspectorate requirements but experiences many barriers, particularly communication with parents of children suspected of being abused. Introduction of a national child abuse protocol can improve screening on child abuse at EDs.
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Directory of Open Access Journals (Sweden)
Cristian G. Rodriguez
2016-01-01
Full Text Available Springs of vibrating screens are prone to fatigue induced failure because they operate in a heavy duty environment, with abrasive dust and under heavy cyclic loads. If a spring breaks, the stiffness at supporting positions changes, and therefore the amplitude of motion and the static and dynamic angular inclination of deck motion also change. This change in the amplitude and in the inclination of motion produces a reduction in separation efficiency. Available models are useful to determine motion under nominal operating conditions when angular displacement is not significant. However in practice there is significant angular motion during startup, during shutdown, or under off-design operating conditions. In this article, a two-dimensional three-degree-of-freedom nonlinear model that considers significant angular motion and damping is developed. The proposed model allows the prediction of vibrating screen behavior when there is a reduction in spring stiffness. Making use of this model for an actual vibrating screen in operation in industry has permitted determining a limit for spring’s failure before separation efficiency is affected. This information is of practical value for operation and maintenance staff helping to determine whether or not it is necessary to change springs, and hence optimizing stoppage time.
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Screening for mental illness: the merger of eugenics and the drug industry.
Sharav, Vera Hassner
2005-01-01
The implementation of a recommendation by the President's New Freedom Commission (NFC) to screen the entire United States population--children first--for presumed, undetected, mental illness is an ill-conceived policy destined for disastrous consequences. The "pseudoscientific" methods used to screen for mental and behavioral abnormalities are a legacy from the discredited ideology of eugenics. Both eugenics and psychiatry suffer from a common philosophical fallacy that undermines the validity of their theories and prescriptions. Both are wed to a faith-based ideological assumption that mental and behavioral manifestations are biologically determined, and are, therefore, ameliorated by biological interventions. NFC promoted the Texas Medication Algorithm Project (TMAP) as a "model" medication treatment plan. The impact of TMAP is evident in the skyrocketing increase in psychotropic drug prescriptions for children and adults, and in the disproportionate expenditure for psychotropic drugs. The New Freedom Commission's screening for mental illness initiative is, therefore, but the first step toward prescribing drugs. The escalating expenditure for psychotropic drugs since TMAP leaves little doubt about who the beneficiaries of TMAP are. Screening for mental illness will increase their use.
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Assessment of biofuels supporting policies using the BioTrans model
International Nuclear Information System (INIS)
Lensink, Sander; Londo, Marc
2010-01-01
The introduction of advanced, 2nd generation biofuels is a difficult to forecast process. Policies may impact the timing of their introduction and the future biofuels mix. The least-cost optimization model BioTrans supports policy analyses on these issues. It includes costs for all parts of the supply chain, and endogenous learning for all biofuels technologies, including cost reductions through scale. BioTrans shows that there are significant lock-in effects favouring traditional biofuels, and that the optimal biofuels mix by 2030 is path dependent. The model captures important barriers for the introduction of emerging technologies, thereby providing valuable quantitative information that can be used in analyses of biofuels supporting policies. It is shown that biodiesel from oil crops will remain a cost effective way of producing biofuels in the medium term at moderate target levels. Aiming solely at least-cost biofuel production is in conflict with a longer term portfolio approach on biofuels, and the desire to come to biofuels with the lowest greenhouse gas emissions. Lowering the targets because of environmental constraints delays the development of 2nd generation biofuels, unless additional policy measures (such as specific sub targets for these fuels) are implemented.
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Useful models for simulating policies to induce technological change
International Nuclear Information System (INIS)
Rivers, Nic; Jaccard, Mark
2006-01-01
Conventional top-down and bottom-up energy-economy models have limitations that affect their usefulness to policy-makers. Efforts to develop hybrid models, that incorporate valuable aspects of these two frameworks, may be more useful by representing technologies in the energy-economy explicitly while also representing more realistically the way in which businesses and consumers choose between those technologies. This representation allows for the realistic simulation of a wide range of technology-specific regulations and fiscal incentives alongside economy-wide fiscal incentives and disincentives. These policies can be assessed based on the costs required to reach a goal in the medium term, as well as on the degree to which they induce technological change that affects costs over long time periods
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International Nuclear Information System (INIS)
Buck, John W.; McDonald, John P.; Taira, Randal Y.
2002-01-01
To support cleanup and closure of these tanks, modeling is performed to understand and predict potential impacts to human health and the environment. Pacific Northwest National Laboratory developed a screening tool for the United States Department of Energy, Office of River Protection that estimates the long-term human health risk, from a strategic planning perspective, posed by potential tank releases to the environment. This tool is being conditioned to more detailed model analyses to ensure consistency between studies and to provide scientific defensibility. Once the conditioning is complete, the system will be used to screen alternative cleanup and closure strategies. The integration of screening and detailed models provides consistent analyses, efficiencies in resources, and positive feedback between the various modeling groups. This approach of conditioning a screening methodology to more detailed analyses provides decision-makers with timely and defensible information and increases confidence in the results on the part of clients, regulators, and stakeholders
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Pharmaceutical expenditure forecast model to support health policy decision making.
Rémuzat, Cécile; Urbinati, Duccio; Kornfeld, Åsa; Vataire, Anne-Lise; Cetinsoy, Laurent; Aballéa, Samuel; Mzoughi, Olfa; Toumi, Mondher
2014-01-01
With constant incentives for healthcare payers to contain their pharmaceutical budgets, modelling policy decision impact became critical. The objective of this project was to test the impact of various policy decisions on pharmaceutical budget (developed for the European Commission for the project 'European Union (EU) Pharmaceutical expenditure forecast' - http://ec.europa.eu/health/healthcare/key_documents/index_en.htm). A model was built to assess policy scenarios' impact on the pharmaceutical budgets of seven member states of the EU, namely France, Germany, Greece, Hungary, Poland, Portugal, and the United Kingdom. The following scenarios were tested: expanding the UK policies to EU, changing time to market access, modifying generic price and penetration, shifting the distribution chain of biosimilars (retail/hospital). Applying the UK policy resulted in dramatic savings for Germany (10 times the base case forecast) and substantial additional savings for France and Portugal (2 and 4 times the base case forecast, respectively). Delaying time to market was found be to a very powerful tool to reduce pharmaceutical expenditure. Applying the EU transparency directive (6-month process for pricing and reimbursement) increased pharmaceutical expenditure for all countries (from 1.1 to 4 times the base case forecast), except in Germany (additional savings). Decreasing the price of generics and boosting the penetration rate, as well as shifting distribution of biosimilars through hospital chain were also key methods to reduce pharmaceutical expenditure. Change in the level of reimbursement rate to 100% in all countries led to an important increase in the pharmaceutical budget. Forecasting pharmaceutical expenditure is a critical exercise to inform policy decision makers. The most important leverages identified by the model on pharmaceutical budget were driven by generic and biosimilar prices, penetration rate, and distribution. Reducing, even slightly, the prices of
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Hill, Caterina; Zurakowski, David; Bennet, Jennifer; Walker-White, Rainelle; Osman, Jamie L; Quarles, Aaron; Oriol, Nancy
2012-03-01
The Family Van mobile health clinic uses a "Knowledgeable Neighbor" model to deliver cost-effective screening and prevention activities in underserved neighborhoods in Boston, MA. We have described the Knowledgeable Neighbor model and used operational data collected from 2006 to 2009 to evaluate the service. The Family Van successfully reached mainly minority low-income men and women. Of the clients screened, 60% had previously undetected elevated blood pressure, 14% had previously undetected elevated blood glucose, and 38% had previously undetected elevated total cholesterol. This represents an important model for reaching underserved communities to deliver proven cost-effective prevention activities, both to help control health care costs and to reduce health disparities.
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Chu, Haitao; Zhou, Yijie; Cole, Stephen R.; Ibrahim, Joseph G.
2010-01-01
Summary To evaluate the probabilities of a disease state, ideally all subjects in a study should be diagnosed by a definitive diagnostic or gold standard test. However, since definitive diagnostic tests are often invasive and expensive, it is generally unethical to apply them to subjects whose screening tests are negative. In this article, we consider latent class models for screening studies with two imperfect binary diagnostic tests and a definitive categorical disease status measured only for those with at least one positive screening test. Specifically, we discuss a conditional independent and three homogeneous conditional dependent latent class models and assess the impact of misspecification of the dependence structure on the estimation of disease category probabilities using frequentist and Bayesian approaches. Interestingly, the three homogeneous dependent models can provide identical goodness-of-fit but substantively different estimates for a given study. However, the parametric form of the assumed dependence structure itself is not “testable” from the data, and thus the dependence structure modeling considered here can only be viewed as a sensitivity analysis concerning a more complicated non-identifiable model potentially involving heterogeneous dependence structure. Furthermore, we discuss Bayesian model averaging together with its limitations as an alternative way to partially address this particularly challenging problem. The methods are applied to two cancer screening studies, and simulations are conducted to evaluate the performance of these methods. In summary, further research is needed to reduce the impact of model misspecification on the estimation of disease prevalence in such settings. PMID:20191614
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Factors Affecting Diabetic Screening Behavior of Korean Adults: A Multilevel Analysis
Directory of Open Access Journals (Sweden)
Hyeongsu Kim, MD, PhD
2013-06-01
Conclusion: This study identified a contextual effect influencing the participation of Korean adults in diabetes screening. It is necessary to develop specific policies that consider not only individual factors, but also community factors relating to individual behaviors to increase the likelihood of diabetes screening.
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Meulen, Miriam P van der; Kapidzic, Atija; Leerdam, Monique E van; van der Steen, Alex; Kuipers, Ernst J; Spaander, Manon C W; de Koning, Harry J; Hol, Lieke; Lansdorp-Vogelaar, Iris
2017-08-01
Background: Several studies suggest that test characteristics for the fecal immunochemical test (FIT) differ by gender, triggering a debate on whether men and women should be screened differently. We used the microsimulation model MISCAN-Colon to evaluate whether screening stratified by gender is cost-effective. Methods: We estimated gender-specific FIT characteristics based on first-round positivity and detection rates observed in a FIT screening pilot (CORERO-1). Subsequently, we used the model to estimate harms, benefits, and costs of 480 gender-specific FIT screening strategies and compared them with uniform screening. Results: Biennial FIT screening from ages 50 to 75 was less effective in women than men [35.7 vs. 49.0 quality-adjusted life years (QALY) gained, respectively] at higher costs (€42,161 vs. -€5,471, respectively). However, the incremental QALYs gained and costs of annual screening compared with biennial screening were more similar for both genders (8.7 QALYs gained and €26,394 for women vs. 6.7 QALYs gained and €20,863 for men). Considering all evaluated screening strategies, optimal gender-based screening yielded at most 7% more QALYs gained than optimal uniform screening and even resulted in equal costs and QALYs gained from a willingness-to-pay threshold of €1,300. Conclusions: FIT screening is less effective in women, but the incremental cost-effectiveness is similar in men and women. Consequently, screening stratified by gender is not more cost-effective than uniform FIT screening. Impact: Our conclusions support the current policy of uniform FIT screening. Cancer Epidemiol Biomarkers Prev; 26(8); 1328-36. ©2017 AACR . ©2017 American Association for Cancer Research.
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Assessing the efficacy of cancer screening
Directory of Open Access Journals (Sweden)
Gemma Jacklyn
2017-07-01
Full Text Available Background: Population-based cancer screening has been established for several types of cancer in Australia and internationally. Screening may perform differently in practice from randomised controlled trials, which makes evaluating programs complex. Materials and methods: We discuss how to assess the evidence of benefits and harms of cancer screening, including the main biases that can mislead clinicians and policy makers (such as volunteer, lead-time, length-time and overdiagnosis bias. We also discuss ways in which communication of risks can inform or mislead the community. Results: The evaluation of cancer screening programs should involve balancing the benefits and harms. When considering the overall worth of an intervention and allocation of scarce health resources, decisions should focus on the net benefits and be informed by systematic reviews. Communication of screening outcomes can be misleading. Many messages highlight the benefits while downplaying the harms, and often use relative risks and 5-year survival to persuade people to screen rather than support informed choice. Lessons learned: An evidence based approach is essential when evaluating and communicating the benefits and harms of cancer screening, to minimise misleading biases and the reliance on intuition.
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Dynamic formulation of a top-down and bottom-up merging energy policy model
International Nuclear Information System (INIS)
Frei, Christoph W.; Haldi, P.-A.; Sarlos, G.Gerard
2003-01-01
The impact of energy policy measures is not restricted to the energy system and should therefore be analysed within an economy-wide framework, while keeping the essential details of the energy sector. The aim of this paper is to present new developments in the field of the consistent evaluation of indicators for the sustainability assessment of energy policy measures. Starting from the static concept of Boehringer (Energy Econ. 20 (1998) 233), this paper shows how the complementarity format can be used in computable general equilibrium (CGE) modelling for a dynamic formulation of bottom-up and top-down approach merging models. While a hybrid approach increases the credibility of CGE models in energy policy analysis by replacing the energy sector generic functional forms with a bottom-up activity analysis based on specific technologies, the endogenous formulation of investment decisions makes an explicit description of evolving specific capital stocks and technology mixes possible. Both features are essential when assessing effects of policy measures that may be affected by structural change--which is typically the case in the long-term assessment of energy policy measures
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International Nuclear Information System (INIS)
Boulanger, Paul-Marie; Brechet, Thierry
2005-01-01
More and more frequently policy-makers are urged to assess the impact of their strategies and policies in terms of sustainable development. This necessitates the use of applied scientific models as tools for identifying and evaluating the likely environmental, economic and social impacts of alternative policies. The objective of this paper is to provide a framework to help decision-makers choose the most appropriate-or the most appropriate mix-of models, by assessing their relative strengths and weaknesses. The paper also allows potential improvements in modeling techniques to be identified. Six modeling paradigms are assessed, both on a general basis and with respect to two specific policy contexts (energy policy, and land use and transport planning)
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A multiple perspective modeling and simulation approach for renewable energy policy evaluation
Alyamani, Talal M.
Environmental issues and reliance on fossil fuel sources, including coal, oil, and natural gas, are the two most common energy issues that are currently faced by the United States (U.S.). Incorporation of renewable energy sources, a non-economical option in electricity generation compared to conventional sources that burn fossil fuels, single handedly promises a viable solution for both of these issues. Several energy policies have concordantly been suggested to reduce the financial burden of adopting renewable energy technologies and make such technologies competitive with conventional sources throughout the U.S. This study presents a modeling and analysis approach for comprehensive evaluation of renewable energy policies with respect to their benefits to various related stakeholders--customers, utilities, governmental and environmental agencies--where the debilitating impacts, advantages, and disadvantages of such policies can be assessed and quantified at the state level. In this work, a novel simulation framework is presented to help policymakers promptly assess and evaluate policies from different perspectives of its stakeholders. The proposed framework is composed of four modules: 1) a database that collates the economic, operational, and environmental data; 2) elucidation of policy, which devises the policy for the simulation model; 3) a preliminary analysis, which makes predictions for consumption, supply, and prices; and 4) a simulation model. After the validity of the proposed framework is demonstrated, a series of planned Florida and Texas renewable energy policies are implemented into the presented framework as case studies. Two solar and one energy efficiency programs are selected as part of the Florida case study. A utility rebate and federal tax credit programs are selected as part of the Texas case study. The results obtained from the simulation and conclusions drawn on the assessment of current energy policies are presented with respect to the
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Using model-based screening to help discover unknown environmental contaminants.
McLachlan, Michael S; Kierkegaard, Amelie; Radke, Michael; Sobek, Anna; Malmvärn, Anna; Alsberg, Tomas; Arnot, Jon A; Brown, Trevor N; Wania, Frank; Breivik, Knut; Xu, Shihe
2014-07-01
Of the tens of thousands of chemicals in use, only a small fraction have been analyzed in environmental samples. To effectively identify environmental contaminants, methods to prioritize chemicals for analytical method development are required. We used a high-throughput model of chemical emissions, fate, and bioaccumulation to identify chemicals likely to have high concentrations in specific environmental media, and we prioritized these for target analysis. This model-based screening was applied to 215 organosilicon chemicals culled from industrial chemical production statistics. The model-based screening prioritized several recognized organosilicon contaminants and generated hypotheses leading to the selection of three chemicals that have not previously been identified as potential environmental contaminants for target analysis. Trace analytical methods were developed, and the chemicals were analyzed in air, sewage sludge, and sediment. All three substances were found to be environmental contaminants. Phenyl-tris(trimethylsiloxy)silane was present in all samples analyzed, with concentrations of ∼50 pg m(-3) in Stockholm air and ∼0.5 ng g(-1) dw in sediment from the Stockholm archipelago. Tris(trifluoropropyl)trimethyl-cyclotrisiloxane and tetrakis(trifluoropropyl)tetramethyl-cyclotetrasiloxane were found in sediments from Lake Mjøsa at ∼1 ng g(-1) dw. The discovery of three novel environmental contaminants shows that models can be useful for prioritizing chemicals for exploratory assessment.
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Improving Safe Sleep Modeling in the Hospital through Policy Implementation.
Heitmann, Rachel; Nilles, Ester K; Jeans, Ashley; Moreland, Jackie; Clarke, Chris; McDonald, Morgan F; Warren, Michael D
2017-11-01
Introduction Sleep-related infant deaths are major contributors to Tennessee's high infant mortality rate. The purpose of this initiative was to evaluate the impact of policy-based efforts to improve modeling of safe sleep practices by health care providers in hospital settings across Tennessee. Methods Safe sleep policies were developed and implemented at 71 hospitals in Tennessee. Policies, at minimum, were required to address staff training on the American Academy of Pediatrics' safe sleep recommendations, correct modeling of infant safe sleep practices, and parent education. Hospital data on process measures related to training and results of crib audits were compiled for analysis. Results The overall observance of infants who were found with any risk factors for unsafe sleep decreased 45.6% (p ≤ 0.001) from the first crib audit to the last crib audit. Significant decreases were noted for specific risk factors, including infants found asleep not on their back, with a toy or object in the crib, and not sleeping in a crib. Significant improvements were observed at hospitals where printed materials or video were utilized for training staff compared to face-to-face training. Discussion Statewide implementation of the hospital policy intervention resulted in significant reductions in infants found in unsafe sleep situations. The most common risk factors for sleep-related infant deaths can be modeled in hospitals. This effort has the potential to reduce sleep-related infant deaths and ultimately infant mortality.
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Dibosa-Osadolor, Onome; Roberts, Tracy
2010-07-01
The aim of this study was to review, systematically and critically, evidence used to derive estimates of cost-effectiveness of human immunodeficiency virus (HIV) screening. A systematic review was conducted. Searched were three main electronic bibliographic databases from 1993 to 2008 using key words including HIV, mass screening, HAART, economic evaluation, cost-effectiveness analysis, modeling. We included studies of sexually transmitted HIV infection in both sexes, including studies comparing diagnostic testing protocols and partner notification. Outcomes included were cases of HIV infection detected, deterioration to the AIDS state, secondary transmission of HIV, the quality-adjusted life-years/survival, costs, and cost-effectiveness of HIV screening. Eighty-four papers were identified; ten of which were formal economic evaluations, one cost study, three effectiveness studies, and three systematic reviews of HIV prevention programs. The predominant assertion was that HIV screening is cost-effective; methodological problems, such as the preponderance of static models which are inappropriate for infectious diseases, varying perspectives from which the studies were analyzed, and arbitrary threshold incremental cost-effectiveness ratio levels, limited the validity of these findings, and their usefulness in informing health policy decisions. The majority of published economic evaluations are based on inappropriate static models. This flaw renders the results of these studies as inconclusive and the purported cost-effectiveness of HIV screening debatable. The results of this review could form a basis for consideration of further research and analysis by health economists into the cost-effectiveness of HIV screening.
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Urban adaptation to mega-drought: Anticipatory water modeling, policy, and planning in Phoenix
Gober, P.; Sampson, D. A.; Quay, R.; White, D. D.; Chow, W.
2016-12-01
There is increasing interest in using the results of water models for long-term planning and policy analysis. Achieving this goal requires more effective integration of human dimensions into water modeling and a paradigm shift in the way models are developed and used. A user-defined focus argues in favor of models that are designed to foster public debate and engagement about the difficult trade-offs that are inevitable in managing complex water systems. These models also emphasize decision making under uncertainty and anticipatory planning, and are developed through a collaborative and iterative process. This paper demonstrates the use of anticipatory modeling for long-term drought planning in Phoenix, one of the largest and fastest growing urban areas in the southwestern USA. WaterSim 5, an anticipatory water policy and planning model, was used to explore groundwater sustainability outcomes for mega-drought conditions across a range of policies, including population growth management, water conservation, water banking, direct reuse of RO reclaimed water, and water augmentation. Results revealed that business-as-usual population growth, per capita use trends, and management strategies may not be sustainable over the long term, even without mega-drought conditions as years of available groundwater supply decline over the simulation period from 2000 to 2060. Adding mega-drought increases the decline in aquifer levels and increases the variability in flows and uncertainty about future groundwater supplies. Simulations that combine drought management policies can return the region to sustainable. Results demonstrate the value of long-term planning and policy analysis for anticipating and adapting to environmental change.
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Alternative policy impacts on US GHG emissions and energy security: A hybrid modeling approach
International Nuclear Information System (INIS)
Sarica, Kemal; Tyner, Wallace E.
2013-01-01
This study addresses the possible impacts of energy and climate policies, namely corporate average fleet efficiency (CAFE) standard, renewable fuel standard (RFS) and clean energy standard (CES), and an economy wide equivalent carbon tax on GHG emissions in the US to the year 2045. Bottom–up and top–down modeling approaches find widespread use in energy economic modeling and policy analysis, in which they differ mainly with respect to the emphasis placed on technology of the energy system and/or the comprehensiveness of endogenous market adjustments. For this study, we use a hybrid energy modeling approach, MARKAL–Macro, that combines the characteristics of two divergent approaches, in order to investigate and quantify the cost of climate policies for the US and an equivalent carbon tax. The approach incorporates Macro-economic feedbacks through a single sector neoclassical growth model while maintaining sectoral and technological detail of the bottom–up optimization framework with endogenous aggregated energy demand. Our analysis is done for two important objectives of the US energy policy: GHG reduction and increased energy security. Our results suggest that the emission tax achieves results quite similar to the CES policy but very different results in the transportation sector. The CAFE standard and RFS are more expensive than a carbon tax for emission reductions. However, the CAFE standard and RFS are much more efficient at achieving crude oil import reductions. The GDP losses are 2.0% and 1.2% relative to the base case for the policy case and carbon tax. That difference may be perceived as being small given the increased energy security gained from the CAFE and RFS policy measures and the uncertainty inherent in this type of analysis. - Highlights: • Evaluates US impacts of three energy/climate policies and a carbon tax (CT) • Analysis done with bottom–up MARKAL model coupled with a macro model • Electricity clean energy standard very close to
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Can the NHS breast screening programme afford not to double read screening mammograms?
International Nuclear Information System (INIS)
Liston, J.C.; Dall, B.J.G.
2003-01-01
AIM: Rapid expansion of the National Health Service (UK) Breast Screening Programme (NHSBSP) to routinely invite women aged 50-70 years will result in many new readers undertaking screen reading. A timely method for assessing performance and preferably one that facilitates a steep learning curve will be required. MATERIALS AND METHODS: This unit screens a population of 88000 women aged 50-64 years and double reads >90% films. A record is kept of proven screen-detected cancers not recalled for assessment by either the first or second reader but correctly recalled following third-reader arbitration. Individual readers' workload and recall rates are obtained by running an annual co-writer report. The results of this 7 year prospective audit are presented. RESULTS: In total 177167 women were screened between 1/4/95 and 31/3/02 resulting in the detection of 1072 cancers. Eighty-seven cancers (8.1%) were detected after arbitration. Individual readers recall to assessment rates and percentage of cases incorrectly returned to routine recall varied. Prompt feedback of missed/misinterpreted cases allowed both experienced and inexperienced readers to modify their recall thresholds for particular mammographic abnormalities. CONCLUSION: It is recommended this audit method is adopted by all units in the NHSBSP and that the Advisory Committee for Breast Cancer Screening review the policy of single versus double reading
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Parameter uncertainty in CGE Modeling of the environmental impacts of economic policies
International Nuclear Information System (INIS)
Abler, D.G.; Shortle, J.S.; Rodriguez, A.G.
1999-01-01
This study explores the role of parameter uncertainty in Computable General Equilibrium (CGE) modeling of the environmental impacts of macroeconomic and sectoral policies, using Costa Rica as a case for study. A CGE model is constructed which includes eight environmental indicators covering deforestation, pesticides, overfishing, hazardous wastes, inorganic wastes, organic wastes, greenhouse gases, and air pollution. The parameters are treated as random variables drawn from prespecified distributions. Evaluation of each policy option consists of a Monte Carlo experiment. The impacts of the policy options on the environmental indicators are relatively robust to different parameter values, in spite of the wide range of parameter values employed. 33 refs
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Parameter uncertainty in CGE Modeling of the environmental impacts of economic policies
Energy Technology Data Exchange (ETDEWEB)
Abler, D.G.; Shortle, J.S. [Agricultural Economics, Pennsylvania State University, University Park, PA (United States); Rodriguez, A.G. [University of Costa Rica, San Jose (Costa Rica)
1999-07-01
This study explores the role of parameter uncertainty in Computable General Equilibrium (CGE) modeling of the environmental impacts of macroeconomic and sectoral policies, using Costa Rica as a case for study. A CGE model is constructed which includes eight environmental indicators covering deforestation, pesticides, overfishing, hazardous wastes, inorganic wastes, organic wastes, greenhouse gases, and air pollution. The parameters are treated as random variables drawn from prespecified distributions. Evaluation of each policy option consists of a Monte Carlo experiment. The impacts of the policy options on the environmental indicators are relatively robust to different parameter values, in spite of the wide range of parameter values employed. 33 refs.
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Eguzkiza, Aitor; Trigo, Jesús Daniel; Martínez-Espronceda, Miguel; Serrano, Luis; Andonegui, José
2015-08-01
Most healthcare services use information and communication technologies to reduce and redistribute the workload associated with follow-up of chronic conditions. However, the lack of normalization of the information handled in and exchanged between such services hinders the scalability and extendibility. The use of medical standards for modelling and exchanging information, especially dual-model based approaches, can enhance the features of screening services. Hence, the approach of this paper is twofold. First, this article presents a generic methodology to model patient-centered clinical processes. Second, a proof of concept of the proposed methodology was conducted within the diabetic retinopathy (DR) screening service of the Health Service of Navarre (Spain) in compliance with a specific dual-model norm (openEHR). As a result, a set of elements required for deploying a model-driven DR screening service has been established, namely: clinical concepts, archetypes, termsets, templates, guideline definition rules, and user interface definitions. This model fosters reusability, because those elements are available to be downloaded and integrated in any healthcare service, and interoperability, since from then on such services can share information seamlessly. Copyright © 2015 Elsevier Inc. All rights reserved.
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Directory of Open Access Journals (Sweden)
Shiela Liviani
2016-06-01
Full Text Available This study aims to analyze the balancing model of agency theory in the effect of debt policy and dividend policy to managerial ownership in manufacture sector companies, which are listed in Indonesia Stock Exchange. Companies in Indonesia tend to have concentrated ownership structure. This condition is contradictory to the previous studies which mostly done in the widely ownership-dispersed countries. Balancing model argues that there is a trade-off between each monitoring and controlling mechanism, i.e. the effect of debt policy to managerial ownership and dividend policy to managerial ownership. This study uses a quantitative approach with fixed effect logistic regression model to analyze the data. Total sample of this study is 1,060 observations of 106 listed Indonesian manufacture firms during the period of 2004-2014. This study found debt policy to be a significant and negative determinant of the level of managerial ownership, as predicted by balancing model of agency theory. This study also found dividend policy has an insignificant positive effect to the level of managerial ownership, which rejected the balancing model of agency theory in the effect of dividend policy to managerial ownership. Penelitian ini bertujuan untuk menguji model keseimbangan teori keagenan pada pengaruh kebijakan utang dan kebijakan dividen terhadap kepemilikan manajerial dalam perusahaan sektor manufaktur yang terdaftar di Bursa Efek Indonesia. Struktur kepemilikan dalam perusahaan-perusahaan di Indonesia cenderung terkonsentrasi. Kondisi ini berbeda dengan penelitian terdahulu yang banyak dilakukan di negara yang struktur kepemilikannya cenderung tersebar. Model keseimbangan menyatakan bahwa terdapat trade-off antar suatu mekanisme pengawasan dan pengendalian dengan mekanisme lainnya, yaitu pengaruh kebijakan utang terhadap kepemilikan manajerial dan kebijakan dividen terhadap kepemilikan manajerial. Penelitian ini menggunakan pendekatan kuantitatif dengan fixed
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Interaction between fiscal and monetary policy in a dynamic nonlinear model.
Bertella, Mario A; Rego, Henio A; Neris, Celso; Silva, Jonathas N; Podobnik, Boris; Stanley, H Eugene
2015-01-01
The objective of this study is to verify the dynamics between fiscal policy, measured by public debt, and monetary policy, measured by a reaction function of a central bank. Changes in monetary policies due to deviations from their targets always generate fiscal impacts. We examine two policy reaction functions: the first related to inflation targets and the second related to economic growth targets. We find that the condition for stable equilibrium is more restrictive in the first case than in the second. We then apply our simulation model to Brazil and United Kingdom and find that the equilibrium is unstable in the Brazilian case but stable in the UK case.
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Including ethical considerations in models for first-trimester screening for pre-eclampsia
DEFF Research Database (Denmark)
Jørgensen, Jennifer Maureen; Hedley, Paula L.; Gjerris, Mickey
2014-01-01
Recent efforts to develop reliable and efficient early pregnancy screening programmes for pre-eclampsia have focused on com-bining clinical, biochemical and biophysical markers. The same model has been used for first-trimester screening for fetal aneuploidies i.e. prenatal diagnosis (PD), which...... is routinely offered to all pregnant women in many developed countries. Some studies suggest combining PD and pre-eclampsia screening, so women can be offered testing for a number of conditions at the same clinical visit. A combination of these tests may be practical in terms of saving time and resources......; however, the combination raises ethical issues. First-trimester PD and pre-eclampsia screening entail qualitative differences which alter the requirements for disclosure, non-directedness and consent with regard to the informed consent process. This article explores the differences related to the ethical...
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Freeman, Dennis S; Hudgins, Cathy; Hornberger, Joel
2018-03-05
The Primary Care Behavioral Health (PCBH) practice model continues to gain converts among primary care and behavioral health professionals as the evidence supporting its effectiveness continues to accumulate. Despite a growing number of practices and organizations using the model effectively, widespread implementation has been hampered by outmoded policies and regulatory barriers. As policymakers and legislators begin to recognize the contributions that PCBH model services make to the care of complex patients and the expansion of access to those in need of behavioral health interventions, some encouraging policy initiatives are emerging and the policy environment is becoming more favorable to implementation of the PCBH model. This article outlines the necessity for policy change, exposing the policy issues and barriers that serve to limit the practice of the PCBH model; highlights innovative approaches some states are taking to foster integrated practice; and discusses the compatibility of the PCBH model with the nation's health care reform agenda. Psychologists have emerged as leaders in the design and implementation of PCBH model integration and are encouraged to continue to advance the model through the demonstration of efficient and effective clinical practice, participation in the expansion of an appropriately trained workforce, and advocacy for the inclusion of this practice model in emerging healthcare systems and value-based payment methodologies.
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A brief history of economic evaluation for human papillomavirus vaccination policy.
Beutels, Philippe; Jit, Mark
2010-09-01
This commentary discusses key issues for health economic evaluation and modelling, applied to human papillomavirus (HPV) vaccine programs. We outline some of the specific features of HPV disease and vaccination, and associated policy questions in light of a literature search for economic evaluations on HPV vaccination. We observe that some policy questions could not be reliably addressed by many of the 43 published economic evaluations we found. Despite this, policy making on universal HPV vaccination followed shortly after vaccine licensure in many developed countries, so the role economic evaluation played in informing these decisions (pre-dating 2008) seems to have been fairly limited. For more recent decisions, however, economic evaluation is likely to have been used more widely and more intensively. We expect future cost-effectiveness analyses to be more instrumental in policy making regarding vaccines covering more HPV types, therapeutic HPV vaccines, and novel diagnostic tests for biomarkers of HPV infection and disease integrated with cervical screening programs.
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A Nuclear Waste Management Cost Model for Policy Analysis
Barron, R. W.; Hill, M. C.
2017-12-01
Although integrated assessments of climate change policy have frequently identified nuclear energy as a promising alternative to fossil fuels, these studies have often treated nuclear waste disposal very simply. Simple assumptions about nuclear waste are problematic because they may not be adequate to capture relevant costs and uncertainties, which could result in suboptimal policy choices. Modeling nuclear waste management costs is a cross-disciplinary, multi-scale problem that involves economic, geologic and environmental processes that operate at vastly different temporal scales. Similarly, the climate-related costs and benefits of nuclear energy are dependent on environmental sensitivity to CO2 emissions and radiation, nuclear energy's ability to offset carbon emissions, and the risk of nuclear accidents, factors which are all deeply uncertain. Alternative value systems further complicate the problem by suggesting different approaches to valuing intergenerational impacts. Effective policy assessment of nuclear energy requires an integrated approach to modeling nuclear waste management that (1) bridges disciplinary and temporal gaps, (2) supports an iterative, adaptive process that responds to evolving understandings of uncertainties, and (3) supports a broad range of value systems. This work develops the Nuclear Waste Management Cost Model (NWMCM). NWMCM provides a flexible framework for evaluating the cost of nuclear waste management across a range of technology pathways and value systems. We illustrate how NWMCM can support policy analysis by estimating how different nuclear waste disposal scenarios developed using the NWMCM framework affect the results of a recent integrated assessment study of alternative energy futures and their effects on the cost of achieving carbon abatement targets. Results suggest that the optimism reflected in previous works is fragile: Plausible nuclear waste management costs and discount rates appropriate for intergenerational cost
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Using Models to Inform Policy: Insights from Modeling the Complexities of Global Polio Eradication
Thompson, Kimberly M.
Drawing on over 20 years of experience modeling risks in complex systems, this talk will challenge SBP participants to develop models that provide timely and useful answers to critical policy questions when decision makers need them. The talk will include reflections on the opportunities and challenges associated with developing integrated models for complex problems and communicating their results effectively. Dr. Thompson will focus the talk largely on collaborative modeling related to global polio eradication and the application of system dynamics tools. After successful global eradication of wild polioviruses, live polioviruses will still present risks that could potentially lead to paralytic polio cases. This talk will present the insights of efforts to use integrated dynamic, probabilistic risk, decision, and economic models to address critical policy questions related to managing global polio risks. Using a dynamic disease transmission model combined with probabilistic model inputs that characterize uncertainty for a stratified world to account for variability, we find that global health leaders will face some difficult choices, but that they can take actions that will manage the risks effectively. The talk will emphasize the need for true collaboration between modelers and subject matter experts, and the importance of working with decision makers as partners to ensure the development of useful models that actually get used.
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Le Doare, Kirsty; O'Driscoll, Megan; Turner, Kim; Seedat, Farah; Russell, Neal J; Seale, Anna C; Heath, Paul T; Lawn, Joy E; Baker, Carol J; Bartlett, Linda; Cutland, Clare; Gravett, Michael G; Ip, Margaret; Madhi, Shabir A; Rubens, Craig E; Saha, Samir K; Schrag, Stephanie; Sobanjo-Ter Meulen, Ajoke; Vekemans, Johan; Kampmann, Beate
2017-11-06
Intrapartum antibiotic chemoprophylaxis (IAP) prevents most early-onset group B streptococcal (GBS) disease. However, there is no description of how IAP is used around the world. This article is the sixth in a series estimating the burden of GBS disease. Here we aimed to review GBS screening policies and IAP implementation worldwide. We identified data through (1) systematic literature reviews (PubMed/Medline, Embase, Literature in the Health Sciences in Latin America and the Caribbean [LILACS], World Health Organization library database [WHOLIS], and Scopus) and unpublished data from professional societies and (2) an online survey and searches of policies from medical societies and professionals. We included data on whether an IAP policy was in use, and if so whether it was based on microbiological or clinical risk factors and how these were applied, as well as the estimated coverage (percentage of women receiving IAP where indicated). We received policy information from 95 of 195 (49%) countries. Of these, 60 of 95 (63%) had an IAP policy; 35 of 60 (58%) used microbiological screening, 25 of 60 (42%) used clinical risk factors. Two of 15 (13%) low-income, 4 of 16 (25%) lower-middle-income, 14 of 20 (70%) upper-middle-income, and 40 of 44 (91%) high-income countries had any IAP policy. The remaining 35 of 95 (37%) had no national policy (25/33 from low-income and lower-middle-income countries). Coverage varied considerably; for microbiological screening, median coverage was 80% (range, 20%-95%); for clinical risk factor-based screening, coverage was 29% (range, 10%-50%). Although there were differences in the microbiological screening methods employed, the individual clinical risk factors used were similar. There is considerable heterogeneity in IAP screening policies and coverage worldwide. Alternative global strategies, such as maternal vaccination, are needed to enhance the scope of global prevention of GBS disease. © The Author 2017. Published by Oxford
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Zeiss, Ragna; van Egmond, S.
2014-01-01
This article studies the roles three science-based models play in Dutch policy and decision making processes. Key is the interaction between model construction and environment. Their political and scientific environments form contexts that shape the roles of models in policy decision making.
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Measurement and Monte Carlo modeling of the spatial response of scintillation screens
Energy Technology Data Exchange (ETDEWEB)
Pistrui-Maximean, S.A. [CNDRI (NDT using Ionizing Radiation) Laboratory, INSA-Lyon, 69621 Villeurbanne (France)], E-mail: spistrui@gmail.com; Letang, J.M. [CNDRI (NDT using Ionizing Radiation) Laboratory, INSA-Lyon, 69621 Villeurbanne (France)], E-mail: jean-michel.letang@insa-lyon.fr; Freud, N. [CNDRI (NDT using Ionizing Radiation) Laboratory, INSA-Lyon, 69621 Villeurbanne (France); Koch, A. [Thales Electron Devices, 38430 Moirans (France); Walenta, A.H. [Detectors and Electronics Department, FB Physik, Siegen University, 57068 Siegen (Germany); Montarou, G. [Corpuscular Physics Laboratory, Blaise Pascal University, 63177 Aubiere (France); Babot, D. [CNDRI (NDT using Ionizing Radiation) Laboratory, INSA-Lyon, 69621 Villeurbanne (France)
2007-11-01
In this article, we propose a detailed protocol to carry out measurements of the spatial response of scintillation screens and to assess the agreement with simulated results. The experimental measurements have been carried out using a practical implementation of the slit method. A Monte Carlo simulation model of scintillator screens, implemented with the toolkit Geant4, has been used to study the influence of the acquisition setup parameters and to compare with the experimental results. An algorithm of global stochastic optimization based on a localized random search method has been implemented to adjust the optical parameters (optical scattering and absorption coefficients). The algorithm has been tested for different X-ray tube voltages (40, 70 and 100 kV). A satisfactory convergence between the results simulated with the optimized model and the experimental measurements is obtained.
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Lessons Learned From A Study Of Genomics-Based Carrier Screening For Reproductive Decision Making.
Wilfond, Benjamin S; Kauffman, Tia L; Jarvik, Gail P; Reiss, Jacob A; Richards, C Sue; McMullen, Carmit; Gilmore, Marian; Himes, Patricia; Kraft, Stephanie A; Porter, Kathryn M; Schneider, Jennifer L; Punj, Sumit; Leo, Michael C; Dickerson, John F; Lynch, Frances L; Clarke, Elizabeth; Rope, Alan F; Lutz, Kevin; Goddard, Katrina A B
2018-05-01
Genomics-based carrier screening is one of many opportunities to use genomic information to inform medical decision making, but clinicians, health care delivery systems, and payers need to determine whether to offer screening and how to do so in an efficient, ethical way. To shed light on this issue, we conducted a study in the period 2014-17 to inform the design of clinical screening programs and guide further health services research. Many of our results have been published elsewhere; this article summarizes the lessons we learned from that study and offers policy insights. Our experience can inform understanding of the potential impact of expanded carrier screening services on health system workflows and workforces-impacts that depend on the details of the screening approach. We found limited patient or health system harms from expanded screening. We also found that some patients valued the information they learned from the process. Future policy discussions should consider the value of offering such expanded carrier screening in health delivery systems with limited resources.
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Interaction between Fiscal and Monetary Policy in a Dynamic Nonlinear Model
Bertella, Mario A.; Rego, Henio A.; Neris, Celso; Silva, Jonathas N.; Podobnik, Boris; Stanley, H. Eugene
2015-01-01
The objective of this study is to verify the dynamics between fiscal policy, measured by public debt, and monetary policy, measured by a reaction function of a central bank. Changes in monetary policies due to deviations from their targets always generate fiscal impacts. We examine two policy reaction functions: the first related to inflation targets and the second related to economic growth targets. We find that the condition for stable equilibrium is more restrictive in the first case than in the second. We then apply our simulation model to Brazil and United Kingdom and find that the equilibrium is unstable in the Brazilian case but stable in the UK case. PMID:25799581
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Transformation of Croatian Disabled Policy: Analysis of Policy Goals
Directory of Open Access Journals (Sweden)
Ana Petek
2010-01-01
Full Text Available The article is based on the idea of transformation of the policy-making mode of Croatian disabled policy, from the medical model, through the social model to the human rights model. The paper highlights 7 elements according to which these models differ, and which are structured into categories of problem-definition, goal-determination and then implementation of disabled policy. The analysis is focused on the goals of Croatian disabled policy, and is based on an interdisciplinary research project of political science, special education and social work. Empirical data were collected by document analysis, by interviewing relevant policy actors and by a survey with the members of representative bodies on all government levels. With the discourse analysis of documents, open coding of interviews and statistical analysis of data collected in the survey, the paper attempts, through the indicator of activity of persons with disability, to answer to what extent Croatian disabled policy is transformed into human rights policy.
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Risk modeling and screening for BRCA1 mutations among Filipino breast cancer patients
International Nuclear Information System (INIS)
Nato, Alejandro Q. Jr.
2003-03-01
Breast cancer susceptibility gene, type 1(BRCA1) has been thought to be responsible for ∼45% of families with multiple breast carcinomas and for ∼80% of breast and ovarian cancer families. In this study, we investigated 34 familial Filipino breast cancer (BC) patients to: (a) estimate breast cancer risks and BRCA1/2 mutation carrier probabilities using risk assessment and prior probability models, respectively; (b) screen for putative polymorphisms at selected smaller exons of BRCA1 by single-strand conformation polymorphism (SSCP) analysis; (c) screen for truncated mutations at BRCA1 exon 11 by radioactive protein truncation test (PTT); and (d) estimate posterior probabilities upon incorporation of screening results. SSCP analysis revealed 8 unique putative polymorphisms. Low prevalence of unique putative polymorphisms at exon 2, 5, 17, and 22 may indicate probable mutations. Contrastingly, high prevalence of unique putative polymorphisms at exons 13, 15, and 16 may suggest true polymorphisms which are biologically insignificant. PTT, DHPLC, and sequence analyses revealed a novel mutation in exon 11 involving GT insertion that resulted to a stop codon which generated a 29.7 kDa truncated protein product. This is the second documented mutation in BRCA1 exon 11 in a Filipino BC patient since 1998. Initial genotype-phenotype correlations in Filipino BC patients may be elucidated based on screening tests performed. Our results corroborate the findings of a study on unselected incident Filipino BC cases where the reported prevalence of BRCA1 mutation is low. The higher prevalence of putative polypmorphisms may be attributed to the increased stringency in patient prospecting. The Gail, Claus, and BRCAPRO models can be utilized to estimate BC risk in unaffected high-risk individuals but validation is needed. Most of the BRCAPRO and Myriad.com prior probability estimates coincide with the presence of BRCA1 mutation and/or putative polymorphisms. This pioneering
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Risk modeling and screening for BRCA1 mutations among Filipino breast cancer patients
Energy Technology Data Exchange (ETDEWEB)
Nato, Jr, Alejandro Q
2003-03-01
Breast cancer susceptibility gene, type 1(BRCA1) has been thought to be responsible for {approx}45% of families with multiple breast carcinomas and for {approx}80% of breast and ovarian cancer families. In this study, we investigated 34 familial Filipino breast cancer (BC) patients to: (a) estimate breast cancer risks and BRCA1/2 mutation carrier probabilities using risk assessment and prior probability models, respectively; (b) screen for putative polymorphisms at selected smaller exons of BRCA1 by single-strand conformation polymorphism (SSCP) analysis; (c) screen for truncated mutations at BRCA1 exon 11 by radioactive protein truncation test (PTT); and (d) estimate posterior probabilities upon incorporation of screening results. SSCP analysis revealed 8 unique putative polymorphisms. Low prevalence of unique putative polymorphisms at exon 2, 5, 17, and 22 may indicate probable mutations. Contrastingly, high prevalence of unique putative polymorphisms at exons 13, 15, and 16 may suggest true polymorphisms which are biologically insignificant. PTT, DHPLC, and sequence analyses revealed a novel mutation in exon 11 involving GT insertion that resulted to a stop codon which generated a 29.7 kDa truncated protein product. This is the second documented mutation in BRCA1 exon 11 in a Filipino BC patient since 1998. Initial genotype-phenotype correlations in Filipino BC patients may be elucidated based on screening tests performed. Our results corroborate the findings of a study on unselected incident Filipino BC cases where the reported prevalence of BRCA1 mutation is low. The higher prevalence of putative polypmorphisms may be attributed to the increased stringency in patient prospecting. The Gail, Claus, and BRCAPRO models can be utilized to estimate BC risk in unaffected high-risk individuals but validation is needed. Most of the BRCAPRO and Myriad.com prior probability estimates coincide with the presence of BRCA1 mutation and/or putative polymorphisms. This
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Posthuma, L.; Klok, C.; Vijver, M.G.; Brink, van den P.J.; Ende, van den F.; Traas, T.P.; Hendriks, A.J.
2005-01-01
Ministries have each their own models to assess risks of chemicals. This report gives an overview of models used in environmental policy to asses risks on ecosystems. Nowadays, many locations deal with contamination that exceeds the risk limits. It therefore becomes crucial for environmental policy
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Tsunematsu, Miwako; Kakehashi, Masayuki
2015-01-01
Background Although the United States Preventive Services Task Force (USPSTF) downgraded their recommendation for breast cancer screening for women aged 40–49 years in 2009, Japanese women in their 40s have been encouraged to attend breast cancer screenings since 2004. The aim of this study is to examine whether these different mass-screening strategies are justifiable by the different situations of these countries and to provide evidence for suitable judgment. Methods Performance of screening strategies (annual/biennial intervals; initiating/terminating ages) was evaluated using a mathematical model based on the natural history of breast cancer and the transition between its stages. Benefits (reduced number of deaths and extended average life expectancy) and harm (false-positives) associated with these strategies were calculated. Results Additional average life expectancy by including women in their 40s as participants were 13 days (26%) and 25 days (22%) in Japan and the United States, respectively, under the biennial screening condition; however, the respective increases in numbers of false-positive cases were 65% and 53% in Japan and the United States. Moreover, the number of screenings needed to detect one diagnosis or to avert one death was smaller when participants were limited to women of age 50 or over than when women in their 40s were included. The validity of including women in their 40s in Japan could not be determined without specifying the weight of harms compared to benefits. Conclusions Whether screening of women in their 40s in Japan is justifiable must be carefully determined based the quantitative balance of benefits and harms. PMID:25483105
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Pataky, Reka; Ismail, Zahra; Coldman, Andrew J; Elwood, Mark; Gelmon, Karen; Hedden, Lindsay; Hislop, Greg; Kan, Lisa; McCoy, Bonnie; Olivotto, Ivo A; Peacock, Stuart
2014-12-01
The sensitivity of screening mammography is much lower among women who have dense breast tissue, compared with women who have largely fatty breasts, and they are also at much higher risk of developing the disease. Increasing mammography screening frequency from biennially to annually has been suggested as a policy option to address the elevated risk in this population. The purpose of this study was to assess the cost-effectiveness of annual versus biennial screening mammography among women aged 50-79 with dense breast tissue. A Markov model was constructed based on screening, diagnostic, and treatment pathways for the population-based screening and cancer care programme in British Columbia, Canada. Model probabilities and screening costs were calculated from screening programme data. Costs for breast cancer treatment were calculated from treatment data, and utility values were obtained from the literature. Incremental cost-effectiveness was expressed as cost per quality adjusted life year (QALY), and probabilistic sensitivity analysis was conducted. Compared with biennial screening, annual screening generated an additional 0.0014 QALYs (95% CI: -0.0480-0.0359) at a cost of $819 ($ = Canadian dollars) per patient (95% CI: 506-1185), resulting in an incremental cost effectiveness ratio of $565,912/QALY. Annual screening had a 37.5% probability of being cost-effective at a willingness-to-pay threshold of $100,000/QALY. There is considerable uncertainty about the incremental cost-effectiveness of annual mammography. Further research on the comparative effectiveness of screening strategies for women with high mammographic breast density is warranted, particularly as digital mammography and density measurement become more widespread, before cost-effectiveness can be reevaluated. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.
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Pharmaceutical expenditure forecast model to support health policy decision making
Rémuzat, Cécile; Urbinati, Duccio; Kornfeld, Åsa; Vataire, Anne-Lise; Cetinsoy, Laurent; Aballéa, Samuel; Mzoughi, Olfa; Toumi, Mondher
2014-01-01
Background and objective With constant incentives for healthcare payers to contain their pharmaceutical budgets, modelling policy decision impact became critical. The objective of this project was to test the impact of various policy decisions on pharmaceutical budget (developed for the European Commission for the project ‘European Union (EU) Pharmaceutical expenditure forecast’ – http://ec.europa.eu/health/healthcare/key_documents/index_en.htm). Methods A model was built to assess policy scenarios’ impact on the pharmaceutical budgets of seven member states of the EU, namely France, Germany, Greece, Hungary, Poland, Portugal, and the United Kingdom. The following scenarios were tested: expanding the UK policies to EU, changing time to market access, modifying generic price and penetration, shifting the distribution chain of biosimilars (retail/hospital). Results Applying the UK policy resulted in dramatic savings for Germany (10 times the base case forecast) and substantial additional savings for France and Portugal (2 and 4 times the base case forecast, respectively). Delaying time to market was found be to a very powerful tool to reduce pharmaceutical expenditure. Applying the EU transparency directive (6-month process for pricing and reimbursement) increased pharmaceutical expenditure for all countries (from 1.1 to 4 times the base case forecast), except in Germany (additional savings). Decreasing the price of generics and boosting the penetration rate, as well as shifting distribution of biosimilars through hospital chain were also key methods to reduce pharmaceutical expenditure. Change in the level of reimbursement rate to 100% in all countries led to an important increase in the pharmaceutical budget. Conclusions Forecasting pharmaceutical expenditure is a critical exercise to inform policy decision makers. The most important leverages identified by the model on pharmaceutical budget were driven by generic and biosimilar prices, penetration rate
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THE HYDROCARBON SPILL SCREENING MODEL (HSSM), VOLUME 2: THEORETICAL BACKGROUND AND SOURCE CODES
A screening model for subsurface release of a nonaqueous phase liquid which is less dense than water (LNAPL) is presented. The model conceptualizes the release as consisting of 1) vertical transport from near the surface to the capillary fringe, 2) radial spreading of an LNAPL l...
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Katki, Hormuzd A; Cheung, Li C; Fetterman, Barbara; Castle, Philip E; Sundaram, Rajeshwari
2015-10-01
New cervical cancer screening guidelines in the US and many European countries recommend that women get tested for human papillomavirus (HPV). To inform decisions about screening intervals, we calculate the increase in precancer/cancer risk per year of continued HPV infection. However, both time to onset of precancer/cancer and time to HPV clearance are interval-censored, and onset of precancer/cancer strongly informatively censors HPV clearance. We analyze this bivariate informatively interval-censored data by developing a novel joint model for time to clearance of HPV and time to precancer/cancer using shared random-effects, where the estimated mean duration of each woman's HPV infection is a covariate in the submodel for time to precancer/cancer. The model was fit to data on 9,553 HPV-positive/Pap-negative women undergoing cervical cancer screening at Kaiser Permanente Northern California, data that were pivotal to the development of US screening guidelines. We compare the implications for screening intervals of this joint model to those from population-average marginal models of precancer/cancer risk. In particular, after 2 years the marginal population-average precancer/cancer risk was 5%, suggesting a 2-year interval to control population-average risk at 5%. In contrast, the joint model reveals that almost all women exceeding 5% individual risk in 2 years also exceeded 5% in 1 year, suggesting that a 1-year interval is better to control individual risk at 5%. The example suggests that sophisticated risk models capable of predicting individual risk may have different implications than population-average risk models that are currently used for informing medical guideline development.
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Gentilello, Larry M; Donato, Anthony; Nolan, Susan; Mackin, Robert E; Liebich, Franesa; Hoyt, David B; LaBrie, Richard A
2005-09-01
Alcohol screening and intervention in trauma centers are widely recommended. The Uniform Accident and Sickness Policy Provision Law (UPPL) exists in most states, and allows insurers to refuse payment for treatment of injuries in patients with a positive alcohol or drug test. This article analyzed the UPPL's impact on screening and reimbursement, measured the knowledge of legislators about substance use problems in trauma centers, and determined their opinions about substance use-related exclusions in insurance contracts for trauma care. A nationwide survey of members of the American Association for the Surgery of Trauma was conducted. A separate survey of legislators who are members of the Senate, House, or Assembly and serve in some leadership role on committees responsible for insurance in their state was also performed. Ninety-eight trauma surgeon and 56 legislator questionnaires were analyzed. Surgeons' familiarity with the UPPL was limited; only 13% believed they practiced in a UPPL state, but 70% actually did. Despite lack of knowledge of the statute, 24% reported an alcohol- or drug-related insurance denial in the past 6 months. This appeared to affect screening practices; the majority of surgeons (51.5%) do not routinely measure blood alcohol concentration, even though over 91% believe blood alcohol concentration testing is important. Most (82%) indicated that if there were no insurance barriers, they would be willing to establish a brief alcohol intervention program in their center. Legislators were aware of the impact of substance use on trauma centers. They overwhelmingly agreed (89%) that alcohol problems are treatable, and 80% believed it is a good idea to offer counseling in trauma centers. As with surgeons, the majority (53%) were not sure whether the UPPL existed in their state, but they favored prohibiting alcohol-related exclusions by a 2:1 ratio, with strong bipartisan support. The study documents strong support for screening and intervention
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APPLICATION OF THE HOWARD'S MODEL ON CONSUMER BEHAVIOR IN BUYING INSURANCE POLICY
Martje Paais; Semuel Souhoka
2017-01-01
This research intends to predict factors that drive consumer to buy insurance policy, based on consumer behavior model by Howard. In main variable used is buying decision. In addition, this study also includes information, brand image, confidence and attitude as the control variables. The analysis units are exclusive policy insured in Malang region. The data was collected using questionnaire. The t-test in simple regression models are used to test hypotheses. The research finds about: first, ...
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Including policy and management in socio-hydrology models: initial conceptualizations
Hermans, Leon; Korbee, Dorien
2017-04-01
Socio-hydrology studies the interactions in coupled human-water systems. So far, the use of dynamic models that capture the direct feedback between societal and hydrological systems has been dominant. What has not yet been included with any particular emphasis, is the policy or management layer, which is a central element in for instance integrated water resources management (IWRM) or adaptive delta management (ADM). Studying the direct interactions between human-water systems generates knowledges that eventually helps influence these interactions in ways that may ensure better outcomes - for society and for the health and sustainability of water systems. This influence sometimes occurs through spontaneous emergence, uncoordinated by societal agents - private sector, citizens, consumers, water users. However, the term 'management' in IWRM and ADM also implies an additional coordinated attempt through various public actors. This contribution is a call to include the policy and management dimension more prominently into the research focus of the socio-hydrology field, and offers first conceptual variables that should be considered in attempts to include this policy or management layer in socio-hydrology models. This is done by drawing on existing frameworks to study policy processes throughout both planning and implementation phases. These include frameworks such as the advocacy coalition framework, collective learning and policy arrangements, which all emphasis longer-term dynamics and feedbacks between actor coalitions in strategic planning and implementation processes. A case about longter-term dynamics in the management of the Haringvliet in the Netherlands is used to illustrate the paper.
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DEFF Research Database (Denmark)
Ernstoff, Alexi S; Fantke, Peter; Huang, Lei
2017-01-01
Specialty software and simplified models are often used to estimate migration of potentially toxic chemicals from packaging into food. Current models, however, are not suitable for emerging applications in decision-support tools, e.g. in Life Cycle Assessment and risk-based screening and prioriti...... to uncertainty and dramatically decreased model performance (R2 = 0.4, Se = 1). In all, this study provides a rapid migration modelling approach to estimate exposure to chemicals in food packaging for emerging screening and prioritization approaches....
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Optimization of Simple Monetary Policy Rules on the Base of Estimated DSGE-model
Shulgin, A.
2015-01-01
Optimization of coefficients in monetary policy rules is performed on the base of the DSGE-model with two independent monetary policy instruments estimated on the Russian data. It was found that welfare maximizing policy rules lead to inadequate result and pro-cyclical monetary policy. Optimal coefficients in Taylor rule and exchange rate rule allow to decrease volatility estimated on Russian data of 2001-2012 by about 20%. The degree of exchange rate flexibility parameter was found to be low...
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Simple model for taking into account the effects of plasma screening in thermonuclear reactions
International Nuclear Information System (INIS)
Shalybkov, D.A.; Yakovlev, D.G.
1988-01-01
In the Thomas-Fermi model of high-density matter analytic calculation is made of the factor by which the rate of the thermonuclear reactions is enhanced by the effects of plasma screening in a degenerate weakly non-ideal electron gas and a strongly nonideal two-component ion liquid with large charge of the ions. The regions of densities and temperatures in which screening due to compressibility of the electron gas plays an important part are found. It is noted that the screening due to this compressibility may be influenced by strong magnetic fields B /approximately/ 10 12 -10 13 G, which quantize the motion of the electrons and change the electron charge screening length in the plasma. The results can be used for the degenerate cores of white dwarfs and shells of neutron stars
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Mesoscale carbon sequestration site screening and CCS infrastructure analysis.
Keating, Gordon N; Middleton, Richard S; Stauffer, Philip H; Viswanathan, Hari S; Letellier, Bruce C; Pasqualini, Donatella; Pawar, Rajesh J; Wolfsberg, Andrew V
2011-01-01
We explore carbon capture and sequestration (CCS) at the meso-scale, a level of study between regional carbon accounting and highly detailed reservoir models for individual sites. We develop an approach to CO(2) sequestration site screening for industries or energy development policies that involves identification of appropriate sequestration basin, analysis of geologic formations, definition of surface sites, design of infrastructure, and analysis of CO(2) transport and storage costs. Our case study involves carbon management for potential oil shale development in the Piceance-Uinta Basin, CO and UT. This study uses new capabilities of the CO(2)-PENS model for site screening, including reservoir capacity, injectivity, and cost calculations for simple reservoirs at multiple sites. We couple this with a model of optimized source-sink-network infrastructure (SimCCS) to design pipeline networks and minimize CCS cost for a given industry or region. The CLEAR(uff) dynamical assessment model calculates the CO(2) source term for various oil production levels. Nine sites in a 13,300 km(2) area have the capacity to store 6.5 GtCO(2), corresponding to shale-oil production of 1.3 Mbbl/day for 50 years (about 1/4 of U.S. crude oil production). Our results highlight the complex, nonlinear relationship between the spatial deployment of CCS infrastructure and the oil-shale production rate.
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Explaining variation in Down's syndrome screening uptake
DEFF Research Database (Denmark)
Crombag, Neeltje M T H; Vellinga, Ynke E; Kluijfhout, Sandra A
2014-01-01
), in an attempt to explain the observed variation in national uptake rates. METHODS: We used a mixed methods approach with an embedded design: a) documentary analysis and b) expert stakeholder analysis. National central statistical offices and legal documents were studied first to gain insight in demographic....... RESULTS: There were many similarities in the demographics, healthcare systems, government abortion legislation and Down's syndrome screening policy across the studied countries. However, the additional cost for Down's syndrome screening over and above standard antenatal care in the Netherlands...
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International Nuclear Information System (INIS)
Zurat, G.J.
1982-01-01
This dissertation assesses four public-policy models by utilizing the case-study approach and personal interviews with the major participants in the public-policy process of Northampton County, Pennsylvania. Northampton County is part of the metropolitan region encompassing Lehigh and Northampton Counties, PA. It is known as the Lehigh Valley which is situated in eastern Pennsylvania. The hypotheses tested in this dissertation are: (1) individual participants have articulated policy models as their frame of reference which guides them in understanding the public policy process, and (2) there is no one best policy model to explain the public-policy process, but the combination of various policy models may improve the policy analysts' understanding of public policy. Results indicate that the major participants have articulated policy models as their frame of reference, but a polarized view of policy models exists for the participants. The second hypothesis was only partially confirmed since the combination of one or more models did not resolve the group/elite policy dilemma of the practitioners. By utilizing stratification theory in the analysis, the group versus elite conflict is clarified and the policy formation phase of the public policy process is understood with respect to the Northamton County Council
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Miglioretti, Diana L; Lange, Jane; van den Broek, Jeroen J; Lee, Christoph I; van Ravesteyn, Nicolien T; Ritley, Dominique; Kerlikowske, Karla; Fenton, Joshua J; Melnikow, Joy; de Koning, Harry J; Hubbard, Rebecca A
2016-02-16
Estimates of risk for radiation-induced breast cancer from mammography screening have not considered variation in dose exposure or diagnostic work-up after abnormal screening results. To estimate distributions of radiation-induced breast cancer incidence and mortality from digital mammography screening while considering exposure from screening and diagnostic mammography and dose variation among women. 2 simulation-modeling approaches. U.S. population. Women aged 40 to 74 years. Annual or biennial digital mammography screening from age 40, 45, or 50 years until age 74 years. Lifetime breast cancer deaths averted (benefits) and radiation-induced breast cancer incidence and mortality (harms) per 100,000 women screened. Annual screening of 100,000 women aged 40 to 74 years was projected to induce 125 breast cancer cases (95% CI, 88 to 178) leading to 16 deaths (CI, 11 to 23), relative to 968 breast cancer deaths averted by early detection from screening. Women exposed at the 95th percentile were projected to develop 246 cases of radiation-induced breast cancer leading to 32 deaths per 100,000 women. Women with large breasts requiring extra views for complete examination (8% of population) were projected to have greater radiation-induced breast cancer risk (266 cancer cases and 35 deaths per 100,000 women) than other women (113 cancer cases and 15 deaths per 100,000 women). Biennial screening starting at age 50 years reduced risk for radiation-induced cancer 5-fold. Life-years lost from radiation-induced breast cancer could not be estimated. Radiation-induced breast cancer incidence and mortality from digital mammography screening are affected by dose variability from screening, resultant diagnostic work-up, initiation age, and screening frequency. Women with large breasts may have a greater risk for radiation-induced breast cancer. Agency for Healthcare Research and Quality, U.S. Preventive Services Task Force, National Cancer Institute.
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Model for determining the completion and production policy in oil wells
Energy Technology Data Exchange (ETDEWEB)
Acurero S, L A
1983-12-01
An optimization scheme for reservoir development was examined considering the value of the resource, choice of completion and production techniques, and boundary conditions for the reservoir. A 3-phase semi-analytic single-well model was formulated to determine the reservoir response for any completion and production policy. Second, an optimization scheme based on the discrete version of the maximum principle of Pontryagin and the Fibonacci search method was formulated to determine the optimal production and completion policy. Both models are combined in a general algorithm of solution proposed to solve the optimization problem, and a computer code was developed and tested.
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Sivaram, Sudha; Majumdar, Gautam; Perin, Douglas; Nessa, Ashrafun; Broeders, Mireille; Lynge, Elsebeth; Saraiya, Mona; Segnan, Nereo; Sankaranarayanan, Rengaswamy; Rajaraman, Preetha; Trimble, Edward; Taplin, Stephen; Rath, G K; Mehrotra, Ravi
2018-02-01
The reductions in cancer morbidity and mortality afforded by population-based cancer screening programmes have led many low-income and middle-income countries to consider the implementation of national screening programmes in the public sector. Screening at the population level, when planned and organised, can greatly benefit the population, whilst disorganised screening can increase costs and reduce benefits. The International Cancer Screening Network (ICSN) was created to share lessons, experience, and evidence regarding cancer screening in countries with organised screening programmes. Organised screening programmes provide screening to an identifiable target population and use multidisciplinary delivery teams, coordinated clinical oversight committees, and regular review by a multidisciplinary evaluation board to maximise benefit to the target population. In this Series paper, we report outcomes of the first regional consultation of the ICSN held in Agartala, India (Sept 5-7, 2016), which included discussions from cancer screening programmes from Denmark, the Netherlands, USA, and Bangladesh. We outline six essential elements of population-based cancer screening programmes, and share recommendations from the meeting that policy makers might want to consider before implementation. Copyright © 2018 Elsevier Ltd. All rights reserved.
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Challenges to cervical screening in a developing country: The case of Malaysia
DEFF Research Database (Denmark)
Othman, Nor Hayati; Rebolj, Matejka
2009-01-01
, only 47.3% of Malaysian women have been screened. Several factors may have contributed to this. No national call-recall system has been established. Women are informed about cervical screening primarily through mass media rather than being individually invited. Smears are free of charge if taken......: Improving screening coverage will remain an important strategy for combating cervical cancer in Malaysia. The focus should be on the policy-making context, improving awareness and the screening infrastructure, and making the service better accessible to women....
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Levy, David; de Almeida, Liz Maria; Szklo, Andre
2012-01-01
Brazil has reduced its smoking rate by about 50% in the last 20 y. During that time period, strong tobacco control policies were implemented. This paper estimates the effect of these stricter policies on smoking prevalence and associated premature mortality, and the effect that additional policies may have. The model was developed using the SimSmoke tobacco control policy model. Using policy, population, and smoking data for Brazil, the model assesses the effect on premature deaths of cigarette taxes, smoke-free air laws, mass media campaigns, marketing restrictions, packaging requirements, cessation treatment programs, and youth access restrictions. We estimate the effect of past policies relative to a counterfactual of policies kept to 1989 levels, and the effect of stricter future policies. Male and female smoking prevalence in Brazil have fallen by about half since 1989, which represents a 46% (lower and upper bounds: 28%-66%) relative reduction compared to the 2010 prevalence under the counterfactual scenario of policies held to 1989 levels. Almost half of that 46% reduction is explained by price increases, 14% by smoke-free air laws, 14% by marketing restrictions, 8% by health warnings, 6% by mass media campaigns, and 10% by cessation treatment programs. As a result of the past policies, a total of almost 420,000 (260,000-715,000) deaths had been averted by 2010, increasing to almost 7 million (4.5 million-10.3 million) deaths projected by 2050. Comparing future implementation of a set of stricter policies to a scenario with 2010 policies held constant, smoking prevalence by 2050 could be reduced by another 39% (29%-54%), and 1.3 million (0.9 million-2.0 million) out of 9 million future premature deaths could be averted. Brazil provides one of the outstanding public health success stories in reducing deaths due to smoking, and serves as a model for other low and middle income nations. However, a set of stricter policies could further reduce smoking and save
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Improving dementia care: The role of screening and detection of cognitive impairment
Borson, Soo; Frank, Lori; Bayley, Peter J.; Boustani, Malaz; Dean, Marge; Lin, Pei-Jung; McCarten, J. Riley; Morris, John C.; Salmon, David P.; Schmitt, Frederick A.; Stefanacci, Richard G.; Mendiondo, Marta S.; Peschin, Susan; Hall, Eric J.; Fillit, Howard; Ashford, J. Wesson
2014-01-01
The value of screening for cognitive impairment, including dementia and Alzheimer's disease, has been debated for decades. Recent research on causes of and treatments for cognitive impairment has converged to challenge previous thinking about screening for cognitive impairment. Consequently, changes have occurred in health care policies and priorities, including the establishment of the annual wellness visit, which requires detection of any cognitive impairment for Medicare enrollees. In response to these changes, the Alzheimer's Foundation of America and the Alzheimer's Drug Discovery Foundation convened a workgroup to review evidence for screening implementation and to evaluate the implications of routine dementia detection for health care redesign. The primary domains reviewed were consideration of the benefits, harms, and impact of cognitive screening on health care quality. In conference, the workgroup developed 10 recommendations for realizing the national policy goals of early detection as the first step in improving clinical care and ensuring proactive, patient-centered management of dementia. PMID:23375564
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METHOD FOR NUMERICAL MODELING OF UNSTEADY SEPARATED FLOW AROUND AIRFOILS MOVING CLOSE TO FLAT SCREEN
Directory of Open Access Journals (Sweden)
V. Pogrebnaya Tamara
2017-01-01
Full Text Available In this article an attempt is made to explain the nature of differences in measurements of forces and moments, which influence an aircraft at take-off and landing when testing on different types of stands. An algorithm for numerical simulation of unsteady separated flow around airfoil is given. The algorithm is based on the combination of discrete vortex method and turbulent boundary layer equations. An unsteady flow separation modeling has been used. At each interval vortex method was used to calculate the potential flow around airfoils located near a screen. Calculated pressures and velocities were then used in boundary layer calculations to determine flow separation points and separated vortex in- tensities. After that calculation were made to determine free vortex positions to next time step and the process was fulfilled for next time step. The proposed algorithm allows using numeric visualization to understand physical picture of flow around airfoil moving close to screen. Three different ways of flow modeling (mirror method, fixed or movable screens were tested. In each case the flow separation process, which determines pressure distribution over airfoil surface and influ- ences aerodynamic performance, was viewed. The results of the calculations showed that at low atitudes of airfoil over screen mirror method over predicts lift force compared with movable screen, while fixed screen under predicts it. The data obtained can be used when designing equipment for testing in wind tunnels.
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Which risk models perform best in selecting ever-smokers for lung cancer screening?
A new analysis by scientists at NCI evaluates nine different individualized lung cancer risk prediction models based on their selections of ever-smokers for computed tomography (CT) lung cancer screening.
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Happell, Brenda; Scott, David; Nankivell, Janette; Platania-Phung, Chris
2013-08-01
To explore nurses' views on the role of nurses in screening and monitoring for physical care of consumers with serious mental illness, at a regional mental health care service. People with serious mental illness experience heightened incidence of preventable and treatable physical illnesses such as cardiovascular disease and diabetes. Screening and monitoring are considered universal clinical safeguards. Nurses can potentially facilitate systematic screening, but their views on physical health care practices are rarely investigated. Qualitative exploratory study. Focus group interviews with 38 nurses of a regional mental health care service district of Australia. To facilitate discussion, participants were presented with a screening system, called the Health Improvement Profile (HIP), as an exemplar of screening of physical health risks by nurses. Inductive data analysis and theme development were guided by a thematic analysis framework. Nurses argued that treatable and preventable physical health problems were common. Four main themes were identified: screening - essential for good practice; the policy-practice gap; 'screening then what?' and, is HIP the answer? Screening and monitoring were considered crucial to proper diagnosis and treatment, however, were not performed systematically or consistently. Nurse readiness for an enhanced role in screening was shaped by: role and responsibility issues, legal liability concerns, funding and staff shortages. Participants were concerned that lack of follow up would limit effectiveness of these interventions. Screening was considered an important clinical step in effective diagnosis and treatment; however, identified barriers need to be addressed to ensure screening is part of a systemic approach to improve physical health of consumers with serious mental illness. Nurses have potential to influence improvement in physical health outcomes for consumers of mental health services. Such potential can only be realised if a
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Freebairn, Louise; Rychetnik, Lucie; Atkinson, Jo-An; Kelly, Paul; McDonnell, Geoff; Roberts, Nick; Whittall, Christine; Redman, Sally
2017-10-02
Evidence-based decision-making is an important foundation for health policy and service planning decisions, yet there remain challenges in ensuring that the many forms of available evidence are considered when decisions are being made. Mobilising knowledge for policy and practice is an emergent process, and one that is highly relational, often messy and profoundly context dependent. Systems approaches, such as dynamic simulation modelling can be used to examine both complex health issues and the context in which they are embedded, and to develop decision support tools. This paper reports on the novel use of participatory simulation modelling as a knowledge mobilisation tool in Australian real-world policy settings. We describe how this approach combined systems science methodology and some of the core elements of knowledge mobilisation best practice. We describe the strategies adopted in three case studies to address both technical and socio-political issues, and compile the experiential lessons derived. Finally, we consider the implications of these knowledge mobilisation case studies and provide evidence for the feasibility of this approach in policy development settings. Participatory dynamic simulation modelling builds on contemporary knowledge mobilisation approaches for health stakeholders to collaborate and explore policy and health service scenarios for priority public health topics. The participatory methods place the decision-maker at the centre of the process and embed deliberative methods and co-production of knowledge. The simulation models function as health policy and programme dynamic decision support tools that integrate diverse forms of evidence, including research evidence, expert knowledge and localised contextual information. Further research is underway to determine the impact of these methods on health service decision-making.
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Semantic policy and adversarial modeling for cyber threat identification and avoidance
DeFrancesco, Anton; McQueary, Bruce
2009-05-01
Today's enterprise networks undergo a relentless barrage of attacks from foreign and domestic adversaries. These attacks may be perpetrated with little to no funding, but may wreck incalculable damage upon the enterprises security, network infrastructure, and services. As more services come online, systems that were once in isolation now provide information that may be combined dynamically with information from other systems to create new meaning on the fly. Security issues are compounded by the potential to aggregate individual pieces of information and infer knowledge at a higher classification than any of its constituent parts. To help alleviate these challenges, in this paper we introduce the notion of semantic policy and discuss how it's use is evolving from a robust approach to access control to preempting and combating attacks in the cyber domain, The introduction of semantic policy and adversarial modeling to network security aims to ask 'where is the network most vulnerable', 'how is the network being attacked', and 'why is the network being attacked'. The first aspect of our approach is integration of semantic policy into enterprise security to augment traditional network security with an overall awareness of policy access and violations. This awareness allows the semantic policy to look at the big picture - analyzing trends and identifying critical relations in system wide data access. The second aspect of our approach is to couple adversarial modeling with semantic policy to move beyond reactive security measures and into a proactive identification of system weaknesses and areas of vulnerability. By utilizing Bayesian-based methodologies, the enterprise wide meaning of data and semantic policy is applied to probability and high-level risk identification. This risk identification will help mitigate potential harm to enterprise networks by enabling resources to proactively isolate, lock-down, and secure systems that are most vulnerable.
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Smith, Alec S T; Macadangdang, Jesse; Leung, Winnie; Laflamme, Michael A; Kim, Deok-Ho
Improved methodologies for modeling cardiac disease phenotypes and accurately screening the efficacy and toxicity of potential therapeutic compounds are actively being sought to advance drug development and improve disease modeling capabilities. To that end, much recent effort has been devoted to the development of novel engineered biomimetic cardiac tissue platforms that accurately recapitulate the structure and function of the human myocardium. Within the field of cardiac engineering, induced pluripotent stem cells (iPSCs) are an exciting tool that offer the potential to advance the current state of the art, as they are derived from somatic cells, enabling the development of personalized medical strategies and patient specific disease models. Here we review different aspects of iPSC-based cardiac engineering technologies. We highlight methods for producing iPSC-derived cardiomyocytes (iPSC-CMs) and discuss their application to compound efficacy/toxicity screening and in vitro modeling of prevalent cardiac diseases. Special attention is paid to the application of micro- and nano-engineering techniques for the development of novel iPSC-CM based platforms and their potential to advance current preclinical screening modalities. Published by Elsevier Inc.
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Arnold, Matthias
2017-12-02
The economic evaluation of stratified breast cancer screening gains momentum, but produces also very diverse results. Systematic reviews so far focused on modeling techniques and epidemiologic assumptions. However, cost and utility parameters received only little attention. This systematic review assesses simulation models for stratified breast cancer screening based on their cost and utility parameters in each phase of breast cancer screening and care. A literature review was conducted to compare economic evaluations with simulation models of personalized breast cancer screening. Study quality was assessed using reporting guidelines. Cost and utility inputs were extracted, standardized and structured using a care delivery framework. Studies were then clustered according to their study aim and parameters were compared within the clusters. Eighteen studies were identified within three study clusters. Reporting quality was very diverse in all three clusters. Only two studies in cluster 1, four studies in cluster 2 and one study in cluster 3 scored high in the quality appraisal. In addition to the quality appraisal, this review assessed if the simulation models were consistent in integrating all relevant phases of care, if utility parameters were consistent and methodological sound and if cost were compatible and consistent in the actual parameters used for screening, diagnostic work up and treatment. Of 18 studies, only three studies did not show signs of potential bias. This systematic review shows that a closer look into the cost and utility parameter can help to identify potential bias. Future simulation models should focus on integrating all relevant phases of care, using methodologically sound utility parameters and avoiding inconsistent cost parameters.
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Weiss, Jennifer M; Pandhi, Nancy; Kraft, Sally; Potvien, Aaron; Carayon, Pascale; Smith, Maureen A
2018-04-25
National colorectal cancer (CRC) screening rates have plateaued. To optimize interventions targeting those unscreened, a better understanding is needed of how this preventive service fits in with multiple preventive and chronic care needs managed by primary care providers (PCPs). This study examines whether PCP practices of other preventive and chronic care needs correlate with CRC screening. We performed a retrospective cohort study of 90 PCPs and 33,137 CRC screening-eligible patients. Five PCP quality metrics (breast cancer screening, cervical cancer screening, HgbA1c and LDL testing, and blood pressure control) were measured. A baseline correlation test was performed between these metrics and PCP CRC screening rates. Multivariable logistic regression with clustering at the clinic-level estimated odds ratios and 95% confidence intervals for these PCP quality metrics, patient and PCP characteristics, and their relationship to CRC screening. PCP CRC screening rates have a strong correlation with breast cancer screening rates (r = 0.7414, p < 0.001) and a weak correlation with the other quality metrics. In the final adjusted model, the only PCP quality metric that significantly predicted CRC screening was breast cancer screening (OR 1.25; 95% CI 1.11-1.42; p < 0.001). PCP CRC screening rates are highly concordant with breast cancer screening. CRC screening is weakly concordant with cervical cancer screening and chronic disease management metrics. Efforts targeting PCPs to increase CRC screening rates could be bundled with breast cancer screening improvement interventions to increase their impact and success.
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How to enhance the future use of energy policy simulation models through ex post validation
International Nuclear Information System (INIS)
Qudrat-Ullah, Hassan
2017-01-01
Although simulation and modeling in general and system dynamics models in particular has long served the energy policy domain, ex post validation of these energy policy models is rarely addressed. In fact, ex post validation is a valuable area of research because it offers modelers a chance to enhance the future use of their simulation models by validating them against the field data. This paper contributes by presenting (i) a system dynamics simulation model, which was developed and used to do a three dimensional, socio-economical and environmental long-term assessment of Pakistan's energy policy in 1999, (ii) a systematic analysis of the 15-years old predictive scenarios produced by a system dynamics simulation model through ex post validation. How did the model predictions compare with the actual data? We report that the ongoing crisis of the electricity sector of Pakistan is unfolding, as the model-based scenarios had projected. - Highlights: • Argues that increased use of energy policy models is dependent on their credibility validation. • An ex post validation process is presented as a solution to build confidence in models. • A unique system dynamics model, MDESRAP, is presented. • The root mean square percentage error and Thiel's inequality statistics are applied. • The dynamic model, MDESRAP, is presented as an ex ante and ex post validated model.
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Robotham, Julie V; Deeny, Sarah R; Fuller, Chris; Hopkins, Susan; Cookson, Barry; Stone, Sheldon
2016-03-01
In December, 2010, National Health Service (NHS) England introduced national mandatory screening of all admissions for meticillin-resistant Staphylococcus aureus (MRSA). We aimed to assess the effectiveness and cost-effectiveness of this policy, from a regional or national health-care decision makers' perspective, compared with alternative screening strategies. We used an individual-based dynamic transmission model parameterised with national MRSA audit data to assess the effectiveness and cost-effectiveness of admission screening of patients in English NHS hospitals compared with five alternative strategies (including no screening, checklist-activated screening, and high-risk specialty-based screening), accompanied by patient isolation and decolonisation, over a 5 year time horizon. We evaluated strategies for different NHS hospital types (acute, teaching, and specialist), MRSA prevalence, and transmission potentials using probabilistic sensitivity analyses. Compared with no screening, mean cost per quality-adjusted life-year (QALY) of screening all admissions was £89,000-148,000 (range £68,000-222,000), and this strategy was consistently more costly and less effective than alternatives for all hospital types. At a £30,000/QALY willingness-to-pay threshold and current prevalence, only the no-screening strategy was cost effective. The next best strategies were, in acute and teaching hospitals, targeting of high-risk specialty admissions (30-40% chance of cost-effectiveness; mean incremental cost-effectiveness ratios [ICERs] £45,200 [range £35,300-61,400] and £48,000/QALY [£34,600-74,800], respectively) and, in specialist hospitals, screening these patients plus risk-factor-based screening of low-risk specialties (a roughly 20% chance of cost-effectiveness; mean ICER £62,600/QALY [£48,000-89,400]). As prevalence and transmission increased, targeting of high-risk specialties became the optimum strategy at the NHS willingness-to-pay threshold (£30,000/QALY
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Modelling and Analysing Access Control Policies in XACML 3.0
DEFF Research Database (Denmark)
Ramli, Carroline Dewi Puspa Kencana
(c.f. GM03,Mos05,Ris13) and manual analysis of the overall effect and consequences of a large XACML policy set is a very daunting and time-consuming task. In this thesis we address the problem of understanding the semantics of access control policy language XACML, in particular XACML version 3.0....... The main focus of this thesis is modelling and analysing access control policies in XACML 3.0. There are two main contributions in this thesis. First, we study and formalise XACML 3.0, in particular the Policy Decision Point (PDP). The concrete syntax of XACML is based on the XML format, while its standard...... semantics is described normatively using natural language. The use of English text in standardisation leads to the risk of misinterpretation and ambiguity. In order to avoid this drawback, we define an abstract syntax of XACML 3.0 and a formal XACML semantics. Second, we propose a logic-based XACML analysis...
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Screening important inputs in models with strong interaction properties
International Nuclear Information System (INIS)
Saltelli, Andrea; Campolongo, Francesca; Cariboni, Jessica
2009-01-01
We introduce a new method for screening inputs in mathematical or computational models with large numbers of inputs. The method proposed here represents an improvement over the best available practice for this setting when dealing with models having strong interaction effects. When the sample size is sufficiently high the same design can also be used to obtain accurate quantitative estimates of the variance-based sensitivity measures: the same simulations can be used to obtain estimates of the variance-based measures according to the Sobol' and the Jansen formulas. Results demonstrate that Sobol' is more efficient for the computation of the first-order indices, while Jansen performs better for the computation of the total indices.
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Screening important inputs in models with strong interaction properties
Energy Technology Data Exchange (ETDEWEB)
Saltelli, Andrea [European Commission, Joint Research Centre, 21020 Ispra, Varese (Italy); Campolongo, Francesca [European Commission, Joint Research Centre, 21020 Ispra, Varese (Italy)], E-mail: francesca.campolongo@jrc.it; Cariboni, Jessica [European Commission, Joint Research Centre, 21020 Ispra, Varese (Italy)
2009-07-15
We introduce a new method for screening inputs in mathematical or computational models with large numbers of inputs. The method proposed here represents an improvement over the best available practice for this setting when dealing with models having strong interaction effects. When the sample size is sufficiently high the same design can also be used to obtain accurate quantitative estimates of the variance-based sensitivity measures: the same simulations can be used to obtain estimates of the variance-based measures according to the Sobol' and the Jansen formulas. Results demonstrate that Sobol' is more efficient for the computation of the first-order indices, while Jansen performs better for the computation of the total indices.
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Optimal Pricing and Advertising Policies for New Product Oligopoly Models
Gerald L. Thompson; Jinn-Tsair Teng
1984-01-01
In this paper our previous work on monopoly and oligopoly new product models is extended by the addition of pricing as well as advertising control variables. These models contain Bass's demand growth model, and the Vidale-Wolfe and Ozga advertising models, as well as the production learning curve model and an exponential demand function. The problem of characterizing an optimal pricing and advertising policy over time is an important question in the field of marketing as well as in the areas ...
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Martin, Michael S; Potter, Beth K; Crocker, Anne G; Wells, George A; Colman, Ian
2016-01-01
The value of screening for mental illness has increasingly been questioned in low prevalence settings due to high false positive rates. However, since false positive rates are related to prevalence, screening may be more effective in higher prevalence settings, including correctional institutions. We compared the yield (i.e. newly detected cases) and efficiency (i.e. false positives) of five screening protocols to detect mental illness in prisons against the use of mental health history taking (the prior approach to detecting mental illness). We estimated the accuracy of the six approaches to detect an Axis I disorder among a sample of 467 newly admitted male inmates (83.1% participation rate). Mental health history taking identified only 41.0% (95% CI 32.1, 50.6) of all inmates with mental illness. Screening protocols identified between 61.9 and 85.7% of all cases, but referred between 2 and 3 additional individuals who did not have a mental illness for every additional case detected compared to the mental health history taking approach. In low prevalence settings (i.e. 10% or less) the screening protocols would have had between 4.6 and 16.2 false positives per true positive. While screening may not be practical in low prevalence settings, it may be beneficial in jails and prisons where the prevalence of mental illness is higher. Further consideration of the context in which screening is being implemented, and of the impacts of policies and clinical practices on the benefits and harms of screening is needed to determine the effectiveness of screening in these settings.
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Directory of Open Access Journals (Sweden)
Michael S Martin
Full Text Available The value of screening for mental illness has increasingly been questioned in low prevalence settings due to high false positive rates. However, since false positive rates are related to prevalence, screening may be more effective in higher prevalence settings, including correctional institutions. We compared the yield (i.e. newly detected cases and efficiency (i.e. false positives of five screening protocols to detect mental illness in prisons against the use of mental health history taking (the prior approach to detecting mental illness.We estimated the accuracy of the six approaches to detect an Axis I disorder among a sample of 467 newly admitted male inmates (83.1% participation rate. Mental health history taking identified only 41.0% (95% CI 32.1, 50.6 of all inmates with mental illness. Screening protocols identified between 61.9 and 85.7% of all cases, but referred between 2 and 3 additional individuals who did not have a mental illness for every additional case detected compared to the mental health history taking approach. In low prevalence settings (i.e. 10% or less the screening protocols would have had between 4.6 and 16.2 false positives per true positive.While screening may not be practical in low prevalence settings, it may be beneficial in jails and prisons where the prevalence of mental illness is higher. Further consideration of the context in which screening is being implemented, and of the impacts of policies and clinical practices on the benefits and harms of screening is needed to determine the effectiveness of screening in these settings.
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Using the Cascade Model to Improve Antenatal Screening for the Hemoglobin Disorders
Gould, Dinah; Papadopoulos, Irena; Kelly, Daniel
2012-01-01
Introduction: The inherited hemoglobin disorders constitute a major public health problem. Facilitators (experienced hemoglobin counselors) were trained to deliver knowledge and skills to "frontline" practitioners to enable them to support parents during antenatal screening via a cascade (train-the-trainer) model. Objectives of…
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Valuing Equal Protection in Aviation Security Screening.
Nguyen, Kenneth D; Rosoff, Heather; John, Richard S
2017-12-01
The growing number of anti-terrorism policies has elevated public concerns about discrimination. Within the context of airport security screening, the current study examines how American travelers value the principle of equal protection by quantifying the "equity premium" that they are willing to sacrifice to avoid screening procedures that result in differential treatments. In addition, we applied the notion of procedural justice to explore the effect of alternative selective screening procedures on the value of equal protection. Two-hundred and twenty-two respondents were randomly assigned to one of three selective screening procedures: (1) randomly, (2) using behavioral indicators, or (3) based on demographic characteristics. They were asked to choose between airlines using either an equal or a discriminatory screening procedure. While the former requires all passengers to be screened in the same manner, the latter mandates all passengers undergo a quick primary screening and, in addition, some passengers are selected for a secondary screening based on a predetermined selection criterion. Equity premiums were quantified in terms of monetary cost, wait time, convenience, and safety compromise. Results show that equity premiums varied greatly across respondents, with many indicating little willingness to sacrifice to avoid inequitable screening, and a smaller minority willing to sacrifice anything to avoid the discriminatory screening. The selective screening manipulation was effective in that equity premiums were greater under selection by demographic characteristics compared to the other two procedures. © 2017 Society for Risk Analysis.
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The Diabetic Retinopathy Screening Workflow
Bolster, Nigel M.; Giardini, Mario E.; Bastawrous, Andrew
2015-01-01
Complications of diabetes mellitus, namely diabetic retinopathy and diabetic maculopathy, are the leading cause of blindness in working aged people. Sufferers can avoid blindness if identified early via retinal imaging. Systematic screening of the diabetic population has been shown to greatly reduce the prevalence and incidence of blindness within the population. Many national screening programs have digital fundus photography as their basis. In the past 5 years several techniques and adapters have been developed that allow digital fundus photography to be performed using smartphones. We review recent progress in smartphone-based fundus imaging and discuss its potential for integration into national systematic diabetic retinopathy screening programs. Some systems have produced promising initial results with respect to their agreement with reference standards. However further multisite trialling of such systems’ use within implementable screening workflows is required if an evidence base strong enough to affect policy change is to be established. If this were to occur national diabetic retinopathy screening would, for the first time, become possible in low- and middle-income settings where cost and availability of trained eye care personnel are currently key barriers to implementation. As diabetes prevalence and incidence is increasing sharply in these settings, the impact on global blindness could be profound. PMID:26596630
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Directory of Open Access Journals (Sweden)
Tetsuya Uetake
2014-08-01
Full Text Available Promoting environmentally friendly farming products is crucial to meeting consumer demand. Although governments implement policy measures to improve the environmental performance of the agriculture sector, theirimpacts are difficult to assess. This study analyses the performance of agri‐environmental policies in Japan, by using the OECD’s policy impact model and reference level framework. In particular, it identifies the environmental impacts of three simulated agri‐environmental policies based on farms’ characteristics. The results suggest that a policy mix of regulation and an incentive payment would reduce environmental impacts, suggesting that targeted approaches could improve the cost‐effectiveness of agri‐environmental policies.
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Sources of change in foreign policy. A review of foreign policy models for developing countries
Directory of Open Access Journals (Sweden)
Alba E. Gámez
2005-05-01
Full Text Available The study of what could be called the reorientation of State foreign policy is not a new phenomenon. Changes in alliances, economic partners and attitudes in the face of international issues have been reflected in myriad texts. Nevertheless, few theoretical frameworksdeal with this issue as an area of study in and of itself. Overcoming this situation would contribute to identifying and comparing the changes in attitude and discourse in the relations between countries, especially in the case of developing countries, and, by extension, thesources of these changes. This article reviews the different models for the analysis of foreign policy, using the conceptual framework of Hermann (1990 as its starting point. This framework suggests the existence of four graded levels of change which allow for studying forms of change which are subtle but important in foreign policy; it also offers a reasoned analysis for testing the relative importance of their sources. This conceptual framework can be situated in the traditional division of levels of analysis: the characteristics of the leader, bureaucratic proposer, internal adjustment, and external impact; and, while it does not provide a conclusive answer, it may be a useful tool in clarifying the ways of using empirical evidence and establishing the relative importance of the sources of change in foreign policy orientation.
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Mandelblatt, Jeanne; van Ravesteyn, Nicolien; Schechter, Clyde; Chang, Yaojen; Huang, An-Tsun; Near, Aimee M; de Koning, Harry; Jemal, Ahmedin
2013-07-15
US breast cancer mortality is declining, but thousands of women still die each year. Two established simulation models examine 6 strategies that include increased screening and/or treatment or elimination of obesity versus continuation of current patterns. The models use common national data on incidence and obesity prevalence, competing causes of death, mammography characteristics, treatment effects, and survival/cure. Parameters are modified based on obesity (defined as BMI ≥ 30 kg/m(2) ). Outcomes are presented for the year 2025 among women aged 25+ and include numbers of cases, deaths, mammograms and false-positives; age-adjusted incidence and mortality; breast cancer mortality reduction and deaths averted; and probability of dying of breast cancer. If current patterns continue, the models project that there would be about 50,100-57,400 (range across models) annual breast cancer deaths in 2025. If 90% of women were screened annually from ages 40 to 54 and biennially from ages 55 to 99 (or death), then 5100-6100 fewer deaths would occur versus current patterns, but incidence, mammograms, and false-positives would increase. If all women received the indicated systemic treatment (with no screening change), then 11,400-14,500 more deaths would be averted versus current patterns, but increased toxicity could occur. If 100% received screening plus indicated therapy, there would be 18,100-20,400 fewer deaths. Eliminating obesity yields 3300-5700 fewer breast cancer deaths versus continuation of current obesity levels. Maximal reductions in breast cancer deaths could be achieved through optimizing treatment use, followed by increasing screening use and obesity prevention. © 2013 American Cancer Society.
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iScreen: Image-Based High-Content RNAi Screening Analysis Tools.
Zhong, Rui; Dong, Xiaonan; Levine, Beth; Xie, Yang; Xiao, Guanghua
2015-09-01
High-throughput RNA interference (RNAi) screening has opened up a path to investigating functional genomics in a genome-wide pattern. However, such studies are often restricted to assays that have a single readout format. Recently, advanced image technologies have been coupled with high-throughput RNAi screening to develop high-content screening, in which one or more cell image(s), instead of a single readout, were generated from each well. This image-based high-content screening technology has led to genome-wide functional annotation in a wider spectrum of biological research studies, as well as in drug and target discovery, so that complex cellular phenotypes can be measured in a multiparametric format. Despite these advances, data analysis and visualization tools are still largely lacking for these types of experiments. Therefore, we developed iScreen (image-Based High-content RNAi Screening Analysis Tool), an R package for the statistical modeling and visualization of image-based high-content RNAi screening. Two case studies were used to demonstrate the capability and efficiency of the iScreen package. iScreen is available for download on CRAN (http://cran.cnr.berkeley.edu/web/packages/iScreen/index.html). The user manual is also available as a supplementary document. © 2014 Society for Laboratory Automation and Screening.
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A Dynamic Model of Post-Traumatic Stress Disorder for Military Personnel and Veterans.
Directory of Open Access Journals (Sweden)
Navid Ghaffarzadegan
Full Text Available Post-traumatic stress disorder (PTSD stands out as a major mental illness; however, little is known about effective policies for mitigating the problem. The importance and complexity of PTSD raise critical questions: What are the trends in the population of PTSD patients among military personnel and veterans in the postwar era? What policies can help mitigate PTSD? To address these questions, we developed a system dynamics simulation model of the population of military personnel and veterans affected by PTSD. The model includes both military personnel and veterans in a "system of systems." This is a novel aspect of our model, since many policies implemented at the military level will potentially influence (and may have side effects on veterans and the Department of Veterans Affairs. The model is first validated by replicating the historical data on PTSD prevalence among military personnel and veterans from 2000 to 2014 (datasets from the Department of Defense, the Institute of Medicine, the Department of Veterans Affairs, and other sources. The model is then used for health policy analysis. Our results show that, in an optimistic scenario based on the status quo of deployment to intense/combat zones, estimated PTSD prevalence among veterans will be at least 10% during the next decade. The model postulates that during wars, resiliency-related policies are the most effective for decreasing PTSD. In a postwar period, current health policy interventions (e.g., screening and treatment have marginal effects on mitigating the problem of PTSD, that is, the current screening and treatment policies must be revolutionized to have any noticeable effect. Furthermore, the simulation results show that it takes a long time, on the order of 40 years, to mitigate the psychiatric consequences of a war. Policy and financial implications of the findings are discussed.
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A Dynamic Model of Post-Traumatic Stress Disorder for Military Personnel and Veterans
Ghaffarzadegan, Navid; Ebrahimvandi, Alireza; Jalali, Mohammad S.
2016-01-01
Post-traumatic stress disorder (PTSD) stands out as a major mental illness; however, little is known about effective policies for mitigating the problem. The importance and complexity of PTSD raise critical questions: What are the trends in the population of PTSD patients among military personnel and veterans in the postwar era? What policies can help mitigate PTSD? To address these questions, we developed a system dynamics simulation model of the population of military personnel and veterans affected by PTSD. The model includes both military personnel and veterans in a “system of systems.” This is a novel aspect of our model, since many policies implemented at the military level will potentially influence (and may have side effects on) veterans and the Department of Veterans Affairs. The model is first validated by replicating the historical data on PTSD prevalence among military personnel and veterans from 2000 to 2014 (datasets from the Department of Defense, the Institute of Medicine, the Department of Veterans Affairs, and other sources). The model is then used for health policy analysis. Our results show that, in an optimistic scenario based on the status quo of deployment to intense/combat zones, estimated PTSD prevalence among veterans will be at least 10% during the next decade. The model postulates that during wars, resiliency-related policies are the most effective for decreasing PTSD. In a postwar period, current health policy interventions (e.g., screening and treatment) have marginal effects on mitigating the problem of PTSD, that is, the current screening and treatment policies must be revolutionized to have any noticeable effect. Furthermore, the simulation results show that it takes a long time, on the order of 40 years, to mitigate the psychiatric consequences of a war. Policy and financial implications of the findings are discussed. PMID:27716776
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This presentation discusses methods used to extrapolate from in vitro high-throughput screening (HTS) toxicity data for an endocrine pathway to in vivo for early life stages in humans, and the use of a life stage PBPK model to address rapidly changing physiological parameters. A...
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Computable general equilibrium modelling in the context of trade and environmental policy
Energy Technology Data Exchange (ETDEWEB)
Koesler, Simon Tobias
2014-10-14
This thesis is dedicated to the evaluation of environmental policies in the context of climate change. Its objectives are twofold. Its first part is devoted to the development of potent instruments for quantitative impact analysis of environmental policy. In this context, the main contributions include the development of a new computable general equilibrium (CGE) model which makes use of the new comprehensive and coherent World Input-Output Dataset (WIOD) and which features a detailed representation of bilateral and bisectoral trade flows. Moreover it features an investigation of input substitutability to provide modellers with adequate estimates for key elasticities as well as a discussion and amelioration of the standard base year calibration procedure of most CGE models. Building on these tools, the second part applies the improved modelling framework and studies the economic implications of environmental policy. This includes an analysis of so called rebound effects, which are triggered by energy efficiency improvements and reduce their net benefit, an investigation of how firms restructure their production processes in the presence of carbon pricing mechanisms, and an analysis of a regional maritime emission trading scheme as one of the possible options to reduce emissions of international shipping in the EU context.
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Computable general equilibrium modelling in the context of trade and environmental policy
International Nuclear Information System (INIS)
Koesler, Simon Tobias
2014-01-01
This thesis is dedicated to the evaluation of environmental policies in the context of climate change. Its objectives are twofold. Its first part is devoted to the development of potent instruments for quantitative impact analysis of environmental policy. In this context, the main contributions include the development of a new computable general equilibrium (CGE) model which makes use of the new comprehensive and coherent World Input-Output Dataset (WIOD) and which features a detailed representation of bilateral and bisectoral trade flows. Moreover it features an investigation of input substitutability to provide modellers with adequate estimates for key elasticities as well as a discussion and amelioration of the standard base year calibration procedure of most CGE models. Building on these tools, the second part applies the improved modelling framework and studies the economic implications of environmental policy. This includes an analysis of so called rebound effects, which are triggered by energy efficiency improvements and reduce their net benefit, an investigation of how firms restructure their production processes in the presence of carbon pricing mechanisms, and an analysis of a regional maritime emission trading scheme as one of the possible options to reduce emissions of international shipping in the EU context.
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More comprehensive discussion of CRC screening associated with higher screening.
Mosen, David M; Feldstein, Adrianne C; Perrin, Nancy A; Rosales, A Gabriella; Smith, David H; Liles, Elizabeth G; Schneider, Jennifer L; Meyers, Ronald E; Elston-Lafata, Jennifer
2013-04-01
Examine association of comprehensiveness of colorectal cancer (CRC) screening discussion by primary care physicians (PCPs) with completion of CRC screening. Observational study in Kaiser Permanente Northwest, a group-model health maintenance organization. A total of 883 participants overdue for CRC screening received an automated telephone call (ATC) between April and June 2009 encouraging CRC screening. Between January and March 2010, participants completed a survey on PCPs' discussion of CRC screening and patient beliefs regarding screening. receipt of CRC screening (assessed by electronic medical record [EMR], 9 months after ATC). Primary independent variable: comprehensiveness of CRC screening discussion by PCPs (7-item scale). Secondary independent variables: perceived benefits of screening (4-item scale assessing respondents' agreement with benefits of timely screening) and primary care utilization (EMR; 9 months after ATC). The independent association of variables with CRC screening was assessed with logistic regression. Average scores for comprehensiveness of CRC discussion and perceived benefits were 0.4 (range 0-1) and 4.0 (range 1-5), respectively. A total of 28.2% (n = 249) completed screening, 84% of whom had survey assessments after their screening date. Of screeners, 95.2% completed the fecal immunochemical test. More comprehensive discussion of CRC screening was associated with increased screening (odds ratio [OR] = 1.51, 95% confidence interval [CI] = 1.03-2.21). Higher perceived benefits (OR = 1.46, 95% CI = 1.13-1.90) and 1 or more PCP visits (OR = 5.82, 95% CI = 3.87-8.74) were also associated with increased screening. More comprehensive discussion of CRC screening was independently associated with increased CRC screening. Primary care utilization was even more strongly associated with CRC screening, irrespective of discussion of CRC screening.
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HIV prevention policy and programme planning: What can mathematical modelling contribute?
Hankins, C.A.
2014-01-01
This thesis explores the potential contribution of mathematical modelling to informed decision-making on policy and programme planning for novel HIV prevention tools. Its hypothesis is that, under certain conditions, modelling results can be a useful addition to the evidence and other factors that
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Kong, Chung Yin; Sigel, Keith; Criss, Steven D; Sheehan, Deirdre F; Triplette, Matthew; Silverberg, Michael J; Henschke, Claudia I; Justice, Amy; Braithwaite, R Scott; Wisnivesky, Juan; Crothers, Kristina
2018-04-19
Lung cancer is the leading cause of non-AIDS-defining cancer deaths among HIV-infected individuals. Although lung cancer screening with low-dose computed tomography (LDCT) is endorsed by multiple national organizations, whether HIV-infected individuals would have similar benefit as uninfected individuals from lung cancer screening is unknown. Our objective was to determine the benefits and harms of lung cancer screening among HIV-infected individuals. We modified an existing simulation model, the Lung Cancer Policy Model, for HIV-infected patients. Veterans Aging Cohort Study, Kaiser Permanente Northern California HIV Cohort, and medical literature. Target population: HIV-infected current and former smokers. Lifetime. Population. Annual LDCT screening from ages 45, 50, or 55 until ages 72 or 77 years. Benefits assessed included lung cancer mortality reduction and life-years gained; harms assessed included numbers of LDCT examinations, false-positive results, and overdiagnosed cases. For HIV-infected patients with CD4 at least 500 and 100% antiretroviral therapy adherence, screening using the Centers for Medicare & Medicaid Services criteria (age 55-77, 30 pack-years of smoking, current smoker or quit within 15 years of screening) would reduce lung cancer mortality by 18.9%, similar to the mortality reduction of uninfected individuals. Alternative screening strategies utilizing lower screening age and/or pack-years criteria increase mortality reduction, but require more LDCT examinations. Strategies assumed 100% screening adherence. Lung cancer screening reduces mortality in HIV-infected patients with CD4 at least l500, with a number of efficient strategies for eligibility, including the current Centers for Medicare & Medicaid Services criteria.
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A simulation model for reliability-based appraisal of an energy policy: The case of Lebanon
International Nuclear Information System (INIS)
Hamdan, H.A.; Ghajar, R.F.; Chedid, R.B.
2012-01-01
The Lebanese Electric Power System (LEPS) has been suffering from technical and financial deficiencies for decades and mirrors the problems encountered in many developing countries suffering from inadequate or no power systems planning resulting in incomplete and ill-operating infrastructure, and suffering from effects of political instability, huge debts, unavailability of financing desired projects and inefficiency in operation. The upgrade and development of the system necessitate the adoption of a comprehensive energy policy that introduces solutions to a diversity of problems addressing the technical, financial, administrative and governance aspects of the system. In this paper, an energy policy for Lebanon is proposed and evaluated based on integration between energy modeling and financial modeling. The paper utilizes the Load Modification Technique (LMT) as a probabilistic tool to assess the impact of policy implementation on energy production, overall cost, technical/commercial losses and reliability. Scenarios reflecting implementation of policy projects are assessed and their impacts are compared with business-as-usual scenarios which assume no new investment is to take place in the sector. Conclusions are drawn on the usefulness of the proposed evaluation methodology and the effectiveness of the adopted energy policy for Lebanon and other developing countries suffering from similar power system problems. - Highlights: ► Evaluation methodology based on a probabilistic simulation tool is proposed. ► A business-as-usual scenario for a given study period of the LEPS was modeled. ► Mitigation scenarios reflecting implementation of the energy policy are modeled. ► Policy simulated and compared with business-as-usual scenarios of the LEPS. ► Results reflect usefulness of proposed methodology and the adopted energy policy.
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Conceptual design of an integrated technology model for carbon policy assessment.
Energy Technology Data Exchange (ETDEWEB)
Backus, George A.; Dimotakes, Paul E. (NASA Jet Propulsion Laboratory, Pasadena, CA)
2011-01-01
This report describes the conceptual design of a technology choice model for understanding strategies to reduce carbon intensity in the electricity sector. The report considers the major modeling issues affecting technology policy assessment and defines an implementable model construct. Further, the report delineates the basis causal structure of such a model and attempts to establish the technical/algorithmic viability of pursuing model development along with the associated analyses.
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Croll, Peter R
2011-02-01
To ensure that patient confidentiality is securely maintained, health ICT applications that contain sensitive personal information demand comprehensive privacy policies. Determining the adequacy of these policies to meet legal conformity together with clinical users and patient expectation is demanding in practice. Organisations and agencies looking to analyse their Privacy and Security policies can benefit from guidance provided by outside entities such as the Privacy Office of their State or Government together with law firms and ICT specialists. The advice given is not uniform and often open to different interpretations. Of greater concern is the possibility of overlooking any important aspects that later result in a data breach. Based on three case studies, this paper considers whether a more formal approach to privacy analysis could be taken that would help identify the full coverage of a Privacy Impact Analysis and determine the deficiencies with an organisation's current policies and approach. A diagrammatic model showing the relationships between Confidentiality, Privacy, Trust, Security and Safety is introduced. First the validity of this model is determined by mapping it against the real-world case studies taken from three healthcare services that depend on ICT. Then, by using software engineering methods, a formal mapping of the relationships is undertaken to identify a full set of policies needed to satisfy the model. How effective this approach may prove as a generic method for deriving a comprehensive set of policies in health ICT applications is finally discussed. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.
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DEFF Research Database (Denmark)
Ghiglino, Christian; Tvede, Mich
for generations, through fiscal policy, i.e. monetary transfers and taxes. Both situations with and without time discounting are considered. It is shown that if the discount factor is suffciently close to one then the optimal policy stabilizes the economy, i.e. the equilibrium path has the turnpike property...
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DEFF Research Database (Denmark)
Ghiglino, Christian; Tvede, Mich
2000-01-01
for generations, through fiscal policy, i.e., monetary transfers and taxes. Situations both with and without time discounting are considered. It is shown that if the discount factor is sufficiently close to one then the optimal policy stabilizes the economy, i.e. the equilibrium path has the turnpike property...
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Anticipating the uncertain: economic modeling and climate change policy
Energy Technology Data Exchange (ETDEWEB)
Jensen, Svenn
2012-11-01
With this thesis I wish to contribute to the understanding of how uncertainty and the anticipation of future events by economic actors affect climate policies. The thesis consists of four papers. Two papers are analytical models which explicitly consider that emissions are caused by extracting scarce fossil fuels which in the future must be replaced by clean technologies. The other two are so called numerical integrated assessment models. Such models represent the world economy, the climate system and the interactions between those two quantitatively, complementing more abstract theoretical work. Should policy makers discriminate between subsidizing renewable energy sources such as wind or solar power, and technologies such as carbon capture and storage (CCS)? Focusing only on the dynamic supply of fossil fuels and hence Co{sub 2}, we find here that cheaper future renewables cause extraction to speed up, lower costs of CCS may delay it. CCS hence may dampen the dynamic inefficiency caused by the absence of comprehensive climate policies today. Does it matter whether uncertainty about future damage assessment is due to scientific complexities or stems from the political process? In paper two, I find that political and scientific uncertainties have opposing effects on the incentives to investment in renewables and the extraction of fossil fuels: The prospect of scientific learning about the climate system increases investment incentives and, ceteris paribus, slows extraction down; uncertainty about future political constellations does the opposite. The optimal carbon tax under scientific uncertainty equals expected marginal damages, whereas political uncertainty demands a tax below marginal damages that decreases over time. Does uncertainty about economic growth impact optimal climate policy today? Here we are the first to consistently analyze how uncertainty about future economic growth affects optimal emission reductions and the optimal social cost of carbon. We
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Directory of Open Access Journals (Sweden)
Masanobu Kii
2014-03-01
This study demonstrates the applicability of a land-use transport model to the assessment of urban policies for building smart communities. First, we outline a model that explicitly formulates the actors' location-related decisions and travel behavior. Second, we apply this model to two urban policies – road pricing and land-use regulation – to assess their long-term impact on energy saving and sustainability using the case of a simplified synthetic city. Our study verifies that, under assumed conditions, the model has the capacity to assess urban policies on energy use and sustainability in a consistent fashion.
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Birnbaum, Jeanette; Gadi, Vijayakrishna K; Markowitz, Elan; Etzioni, Ruth
2016-02-16
Mammography trials, which are the primary sources of evidence for screening benefit, were conducted decades ago. Whether advances in systemic therapies have rendered previously observed benefits of screening less significant is unknown. To compare the outcomes of breast cancer screening trials had they been conducted using contemporary systemic treatments with outcomes of trials conducted with previously used treatments. Computer simulation model of 3 virtual screening trials with similar reductions in advanced-stage cancer cases but reflecting treatment patterns in 1975 (prechemotherapy era), 1999, or 2015 (treatment according to receptor status). Meta-analyses of screening and treatment trials; study of dissemination of primary systemic treatments; SEER (Surveillance, Epidemiology, and End Results) registry. U.S. women aged 50 to 74 years. 10 and 25 years. Population. Mammography, chemotherapy, tamoxifen, aromatase inhibitors, and trastuzumab. Breast cancer mortality rate ratio (MRR) and absolute risk reduction (ARR) obtained by the difference in cumulative breast cancer mortality between control and screening groups. At 10 years, screening in a 1975 trial yielded an MRR of 90% and an ARR of 5 deaths per 10,000 women. A 2015 screening trial yielded a 10-year MRR of 90% and an ARR of 3 deaths per 10,000 women. Greater reductions in advanced-stage disease yielded a greater screening effect, but MRRs remained similar across trials. However, ARRs were consistently lower under contemporary treatments. When contemporary treatments were available only for early-stage cases, the MRR was 88%. Disease models simplify reality and cannot capture all breast cancer subtypes. Advances in systemic therapies for breast cancer have not substantively reduced the relative benefits of screening but have likely reduced the absolute benefits because of their positive effect on breast cancer survival. University of Washington and National Cancer Institute.
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Hospitalized women's willingness to pay for an inpatient screening mammogram.
Khaliq, Waseem; Harris, Ché Matthew; Landis, Regina; Bridges, John F P; Wright, Scott M
2014-01-01
Lower rates for breast cancer screening persist among low income and uninsured women. Although Medicare and many other insurance plans would pay for screening mammograms done during hospital stays, breast cancer screening has not been part of usual hospital care. This study explores the mean amount of money that hospitalized women were willing to contribute towards the cost of a screening mammogram. Of the 193 enrolled patients, 72% were willing to pay a mean of $83.41 (95% CI, $71.51-$95.31) in advance towards inpatient screening mammogram costs. The study's findings suggest that hospitalized women value the prospect of screening mammography during the hospitalization. It may be wise policy to offer mammograms to nonadherent hospitalized women, especially those who are at high risk for developing breast cancer. © 2014 Annals of Family Medicine, Inc.
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National policies on the management of latent tuberculosis infection: review of 98 countries
Jagger, Ann; Reiter-karam, Silke; Getahun, Haileyesus
2018-01-01
Abstract Objective To review policies on management of latent tuberculosis infection in countries with low and high burdens of tuberculosis. Methods We divided countries reporting data to the World Health Organization (WHO) Global Tuberculosis Programme into low and high tuberculosis burden, based on WHO criteria. We identified national policy documents on management of latent tuberculosis through online searches, government websites, WHO country offices and personal communication with programme managers. We made a descriptive analysis with a focus on policy gaps and deviations from WHO policy recommendations. Findings We obtained documents from 68 of 113 low-burden countries and 30 of 35 countries with the highest burdens of tuberculosis or human immunodeficiency virus (HIV)-associated tuberculosis. Screening and treatment of latent tuberculosis infection in people living with HIV was recommended in guidelines of 29 (96.7%) high-burden and 54 (79.7%) low-burden countries. Screening for children aged countries. In most high-burden countries the recommendation was symptom screening alone before treatment, whereas in all low-burden countries it was testing before treatment. Some low-burden countries’ policies did not comply with WHO recommendations: nine (13.2%) recommended tuberculosis preventive treatment for travellers to high-burden countries and 10 (14.7%) for patients undergoing abdominal surgery. Conclusion Lack of solid evidence on certain aspects of management of latent tuberculosis infection results in national policies which vary considerably. This highlights a need to advance research and develop clear, implementable and evidence-based WHO policies. PMID:29531416
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Directory of Open Access Journals (Sweden)
Soleiman Ahmady
2016-12-01
Full Text Available Experts in the field of human resource management have always emphasized on human work force as the most important strategic factor and the organization's most valuable asset and believe that effective management of human resources is the key to organizational success. Recruitment and selection are one of the aspects of human resource management that are of great importance and adopting appropriate policies in this area could provide the appropriate use of human resources. In universities and higher education institutions, faculty members are one of the major capitals and development and application of appropriate policies play a major role in their success. This study is based on critical review where relevant search terms were used to collect the studies using extensive and structured search of the databases. One hundred fifty titles were retrieved. Then, with purposive sampling, texts screening was conducted in three stages: A primary screening or title screening on the grounds that are associated with managing recruiting faculty members, B secondary screening performed based on study summary and introduction texts, and C tertiary screening: the texts were briefly studied and the texts were prioritized based on conceptual richness and related to contextual studies and irrelevant articles were excluded. Complete and in-depth study of the richest papers began. Forty-five articles and text were examined. The results suggest that in most universities management of recruiting faculty members is decentralized and based on the department. Findings show that policies such as reducing the use of tenure track, the long-term contracts, limiting the tenure to faculty of science, limiting tenure to higher levels of associate professor and design the diverse career paths and different forms of employment are of the policies that can be considered by university managers. The findings also suggest that universities can use flexible policies, such as
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Modelling the Effects of Parking Charge and Supply Policy Using System Dynamics Method
Directory of Open Access Journals (Sweden)
Zhenyu Mei
2017-01-01
Full Text Available Reasonable parking charge and supply policy are essential for the regular operation of the traffic in city center. This paper develops an evaluation model for parking policies using system dynamics. A quantitative study is conducted to examine the effects of parking charge and supply policy on traffic speed. The model, which is composed of three interrelated subsystems, first summarizes the travel cost of each travel mode and then calibrates the travel choice model through the travel mode subsystem. Finally, the subsystem that evaluates the state of traffic forecasts future car speed based on bureau of public roads (BPR function and generates new travel cost until the entire model reaches a steady state. The accuracy of the model is verified in Hangzhou Wulin business district. The related error of predicted speed is only 2.2%. The results indicate that the regular pattern of traffic speed and parking charge can be illustrated using the proposed model based on system dynamics, and the model infers that reducing the parking supply in core area will increase its congestion level and, under certain parking supply conditions, there exists an interval of possible pricing at which the service reaches a level that is fairly stable.
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A groundwater mass flux model for screening the groundwater-to-indoor-air exposure pathway
Energy Technology Data Exchange (ETDEWEB)
McHugh, T.; Blanc, P.C. de; Connor, J. [Groundwater Services Inc, Houston, TX (United States)
2003-07-01
The potential for human exposure via volatilisation of groundwater contaminants into indoor air has been a focus of increasing concern in recent years. At a small number of sites, elevated indoor vapour concentrations have been measured within buildings overlying shallow groundwater contaminated with chlorinated solvents, causing public concern over the potential for similar problems at other corrective action sites. In addition, use of the screening-levelmodel developed by Johnson and Ettinger (1991) for the groundwater-to-indoor-air exposure pathway has suggested that low microgram per litre (ug/L)-range concentrations of either chlorinated or non-chlorinated volatile organic compounds dissolved in groundwater could result in indoor vapour concentrations in excess of applicable risk-based exposure limits. As an alternative screening tool, this paper presents a groundwater mass flux model for evaluation of transport to indoor air. The mass flux model is intended to serve as a highly conservative screening tool that over-predicts groundwater-to-indoor-air mass flux, yet still provides sufficient sensitivity to identify sites for which the groundwater-to-indoor air exposure pathway is not a concern. (orig.)
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Breast cancer screening; cost-effective in practice?
International Nuclear Information System (INIS)
Koning, Harry J. de
2000-01-01
The main aim of national breast screening is a reduction in breast cancer mortality. The data on the reduction in breast cancer mortality from three (of the five) Swedish trials in particular gave rise to the expectation that the Dutch programme of 2-yearly screening for women aged 50-70 would produce a 16% reduction in the total population. In all likelihood, many of the years of life gained as a result of screening are enjoyed in good health. According to its critics the actual benefit that can be achieved from the national breast cancer screening programmes is overstated. Considerable benefits have recently been demonstrated in England and Wales. However, the fall was so considerable in such a relatively short space of time that screening (started in 1987) was thought to only have played a small part. As far as the Dutch screening programme is concerned it is still too early to reach any conclusions about a possible reduction in mortality. The first short-term results of the screening are favourable and as good as (or better than) expectations. In Swedish regions where mammographic screening was introduced, a 19% reduction in breast cancer mortality can be estimated at population level, and recently a 20% reduction was presented in the UK. In countries where women are expected to make appointments for screening themselves, the attendance figures are significantly lower and the quality of the process as a whole is sometimes poorer. The benefits of breast cancer screening need to be carefully balanced against the burden to women and to the health care system. Mass breast screening requires many resources and will be a costly service. Cost-effectiveness of a breast cancer screening programme can be estimated using a computer model. Published cost-effectiveness ratios may differ tremendously, but are often the result of different types of calculation, time periods considered, including or excluding downstream cost. The approach of simulation and estimation is here
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International Nuclear Information System (INIS)
Audinet, P.; Fages, E.
1997-01-01
Feasible policy alternatives are searched for, which could tackle the job market problem, thus achieving the first step towards solving the biomass dependency issue. To do this, an economic model is built which includes specific characteristics of biomass collection and use, such as non-monetary income, determinants of time allocation between formal and informal activities, and energy sources substitutability. The economic features of biomass production and use is studied in order to understand the underlying principles at work at the cross-roads between rural labour market and energy consumption patterns. The issue of fuelwood plantation is examined on a commercial basis using a spread-sheet model to assess its viability and the constraints for the policy maker. An economic model is developed to test the effects of a variety of policy changes on the local economy as described in the spread-sheet framework. The case of India is studied. (K.A.)
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Cost-effectiveness of HIV and syphilis antenatal screening: a modelling study.
Bristow, Claire C; Larson, Elysia; Anderson, Laura J; Klausner, Jeffrey D
2016-08-01
The WHO called for the elimination of maternal-to-child transmission (MTCT) of HIV and syphilis, a harmonised approach for the improvement of health outcomes for mothers and children. Testing early in pregnancy, treating seropositive pregnant women and preventing syphilis reinfection can prevent MTCT of HIV and syphilis. We assessed the health and economic outcomes of a dual testing strategy in a simulated cohort of 100 000 antenatal care patients in Malawi. We compared four screening algorithms: (1) HIV rapid test only, (2) dual HIV and syphilis rapid tests, (3) single rapid tests for HIV and syphilis and (4) HIV rapid and syphilis laboratory tests. We calculated the expected number of adverse pregnancy outcomes, the expected costs and the expected newborn disability-adjusted life years (DALYs) for each screening algorithm. The estimated costs and DALYs for each screening algorithm were assessed from a societal perspective using Markov progression models. Additionally, we conducted a Monte Carlo multiway sensitivity analysis, allowing for ranges of inputs. Our cohort decision model predicted the lowest number of adverse pregnancy outcomes in the dual HIV and syphilis rapid test strategy. Additionally, from the societal perspective, the costs of prevention and care using a dual HIV and syphilis rapid testing strategy was both the least costly ($226.92 per pregnancy) and resulted in the fewest DALYs (116 639) per 100 000 pregnancies. In the Monte Carlo simulation the dual HIV and syphilis algorithm was always cost saving and almost always reduced DALYs compared with HIV testing alone. The results of the cost-effectiveness analysis showed that a dual HIV and syphilis test was cost saving compared with all other screening strategies. Updating existing prevention of mother-to-child HIV transmission programmes in Malawi and similar countries to include dual rapid testing for HIV and syphilis is likely to be advantageous. Published by the BMJ Publishing Group
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Fontaine, Joseph J.; Jorgensen, Christopher; Stuber, Erica F.; Gruber, Lutz F.; Bishop, Andrew A.; Lusk, Jeffrey J.; Zach, Eric S.; Decker, Karie L.
2017-01-01
We know economic and social policy has implications for ecosystems at large, but the consequences for a given geographic area or specific wildlife population are more difficult to conceptualize and communicate. Species distribution models, which extrapolate species-habitat relationships across ecological scales, are capable of predicting population changes in distribution and abundance in response to management and policy, and thus, are an ideal means for facilitating proactive management within a larger policy framework. To illustrate the capabilities of species distribution modeling in scenario planning for wildlife populations, we projected an existing distribution model for ring-necked pheasants (Phasianus colchicus) onto a series of alternative future landscape scenarios for Nebraska, USA. Based on our scenarios, we qualitatively and quantitatively estimated the effects of agricultural policy decisions on pheasant populations across Nebraska, in specific management regions, and at wildlife management areas.
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2013-06-14
... for Responsible Medicine (PCRM), ACC, BCS, and CLA and the Endocrine Policy Forum (EPF)) indicated... chemicals and drinking water contaminants. G. Other Topics 1. Cost sharing. ACC, CLA, EPF, and CPDA stated... should strictly disallow CBI claims. The ACC, CLA, and EPF commented that FFDCA authorized, and EPA...
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The cost-effectiveness of screening for hereditary hemochromatosis in Germany: a remodeling study.
Rogowski, Wolf H
2009-01-01
Genetic tests for hereditary hemochromatosis (HH) are currently included in the German ambulatory care reimbursement scheme but only for symptomatic individuals and the offspring of HH patients. This study synthesizes the most current evidence to examine whether screening in the broader population is cost-effective and to identify the best choice of initial and follow-up screening tests. A probabilistic decision-analytic model was constructed to calculate cost per life year gained (LYG) for HH screening among male Caucasians aged 30. Three strategies were considered in both the general population and male offspring of HH patients: phenotypic (transferrin saturation, TS), genotypic (C282Y mutation), and sequential (genotype if TS is elevated) screening. The incremental cost-effectiveness of sequential screening among male offspring, sequential population-wide screening, and genotypic screening is 41000, 124000, and 161000 Eero/LYG, respectively. All other strategies were subject to simple or extended dominance. The results are subject to high uncertainty. The most influential parameters in the deterministic one-way sensitivity analysis are discounting of life years gained and the adherence of patients to preventive phlebotomy. The current German policy of only screening at-risk individuals is consistent with health economic decision making based on typically accepted thresholds. However, conducting the DNA test after the first elevated TS result is more cost-effective than waiting for a second TS result as recommended by the German guidelines. Further empirical work regarding adherence to long-term prevention recommendations and explicit and well-justified guidance for the choice of discount rates in German economic evaluation are needed.
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Double-dividend analysis with SCREEN: an empirical study for Switzerland
International Nuclear Information System (INIS)
Frei, Christoph W.; Haldi, Pierre-Andre; Sarlos, Gerard
2005-01-01
This paper presents an empirical study that quantifies the effects of an ecological fiscal reform as recently rejected by the Swiss population. The measure aims to encourage employment and, at the same time, to dissuade from an excessive energy use and thereby decrease energy-induced external costs (CO 2 , etc.). The analysis is based on the model SCREEN, a general equilibrium model using the complementarity format for the hybrid description of economy-wide production possibilities where the electricity sector is represented by a bottom-up activity analysis and the other production sectors are characterised by top-down production functions. A dynamic formulation of the activity analysis of technologies allows for the reproduction of endogenous structural change (see Frei, C.W., Haldi, P.-A., Sarlos, G., 2003. Dynamic formulation of a top-down and bottom-up merging energy policy model. Energy Policy 31 (10), 1017-1031.). The labour market is formulated according to the microeconomically founded efficiency wages and calibrated for Switzerland. The study includes the development of a consistent set of top-down, bottom-up and labour data for Switzerland. The collection of bottom-up data on the electricity sector, just before liberalisation, was not easy. The electricity sector characterising data was prepared, based on original statistics about 140 Swiss electricity companies
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Franco, Eduardo L; Tsu, Vivien; Herrero, Rolando; Lazcano-Ponce, Eduardo; Hildesheim, Allan; Muñoz, Nubia; Murillo, Raul; Sánchez, Gloria Ines; Andrus, Jon Kim
2008-08-19
Despite substantial efforts to control cervical cancer by screening, most Latin American and Caribbean countries continue to experience incidence rates of this disease that are much higher than those of other Western countries. The implementation of universal human papillomavirus (HPV) vaccination for young adolescent women is the best prospect for changing this situation. Even though there are financial challenges to overcome to implement such a policy, there is broad political support in the region for adopting universal HPV vaccination. The costs of implementing this policy could be largely alleviated by changing cervical cancer control practices that rely on inefficient use of resources presently allocated to cytology screening. In view of the strong evidence base concerning cervical cancer prevention technologies in the region and the expected impact of vaccination on the performance of cytology, we propose a reformulation of cervical cancer screening policies to be based on HPV testing using validated methods followed by cytologic triage. This approach would serve as the central component of a system that plays the dual role of providing screening and surveillance as integrated and complementary activities sharing centralized resources and coordination.
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2010-11-17
... comments by referencing a Code of Federal Regulations (CFR) part or section number. iii. Explain why you... the record in accordance with section 554 of the Administrative Procedure Act (APA). (15 U.S.C. 2615(a... referencing by parties unfamiliar with the referenced regulation. C. When do these policies and procedures...
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An endogenous Taylor condition in an endogenous growth monetary policy model
Le, Mai Vo; Gillman, Max; Minford, Patrick
2007-01-01
The paper derives a Taylor condition as part of the agent's equilibrium behavior in an endogenous growth monetary economy. It shows the assumptions necessary to make it almost identical to the original Taylor rule, and that it can interchangably take a money supply growth rate form. From the money supply form, simple policy experiments are conducted. A full central bank policy model is derived that includes the Taylor condition along with equations comparable to the standard aggregate-demand/...
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The Policy Dystopia Model: An Interpretive Analysis of Tobacco Industry Political Activity.
Ulucanlar, Selda; Fooks, Gary J; Gilmore, Anna B
2016-09-01
Tobacco industry interference has been identified as the greatest obstacle to the implementation of evidence-based measures to reduce tobacco use. Understanding and addressing industry interference in public health policy-making is therefore crucial. Existing conceptualisations of corporate political activity (CPA) are embedded in a business perspective and do not attend to CPA's social and public health costs; most have not drawn on the unique resource represented by internal tobacco industry documents. Building on this literature, including systematic reviews, we develop a critically informed conceptual model of tobacco industry political activity. We thematically analysed published papers included in two systematic reviews examining tobacco industry influence on taxation and marketing of tobacco; we included 45 of 46 papers in the former category and 20 of 48 papers in the latter (n = 65). We used a grounded theory approach to build taxonomies of "discursive" (argument-based) and "instrumental" (action-based) industry strategies and from these devised the Policy Dystopia Model, which shows that the industry, working through different constituencies, constructs a metanarrative to argue that proposed policies will lead to a dysfunctional future of policy failure and widely dispersed adverse social and economic consequences. Simultaneously, it uses diverse, interlocking insider and outsider instrumental strategies to disseminate this narrative and enhance its persuasiveness in order to secure its preferred policy outcomes. Limitations are that many papers were historical (some dating back to the 1970s) and focused on high-income regions. The model provides an evidence-based, accessible way of understanding diverse corporate political strategies. It should enable public health actors and officials to preempt these strategies and develop realistic assessments of the industry's claims.
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Evaluation of Cannabidiol in Animal Seizure Models by the Epilepsy Therapy Screening Program (ETSP).
Klein, Brian D; Jacobson, Catherine A; Metcalf, Cameron S; Smith, Misty D; Wilcox, Karen S; Hampson, Aidan J; Kehne, John H
2017-07-01
Cannabidiol (CBD) is a cannabinoid component of marijuana that has no significant activity at cannabinoid receptors or psychoactive effects. There is considerable interest in CBD as a therapy for epilepsy. Almost a third of epilepsy patients are not adequately controlled by clinically available anti-seizure drugs (ASDs). Initial studies appear to demonstrate that CBD preparations may be a useful treatment for pharmacoresistant epilepsy. The National Institute of Neurological Disorders and Stroke (NINDS) funded Epilepsy Therapy Screening Program (ETSP) investigated CBD in a battery of seizure models using a refocused screening protocol aimed at identifying pharmacotherapies to address the unmet need in pharmacoresistant epilepsy. Applying this new screening workflow, CBD was investigated in mouse 6 Hz 44 mA, maximal electroshock (MES), corneal kindling models and rat MES and lamotrigine-resistant amygdala kindling models. Following intraperitoneal (i.p.) pretreatment, CBD produced dose-dependent protection in the acute seizure models; mouse 6 Hz 44 mA (ED 50 164 mg/kg), mouse MES (ED 50 83.5 mg/kg) and rat MES (ED 50 88.9 mg/kg). In chronic models, CBD produced dose-dependent protection in the corneal kindled mouse (ED 50 119 mg/kg) but CBD (up to 300 mg/kg) was not protective in the lamotrigine-resistant amygdala kindled rat. Motor impairment assessed in conjunction with the acute seizure models showed that CBD exerted seizure protection at non-impairing doses. The ETSP investigation demonstrates that CBD exhibits anti-seizure properties in acute seizure models and the corneal kindled mouse. However, further preclinical and clinical studies are needed to determine the potential for CBD to address the unmet needs in pharmacoresistant epilepsy.
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Directory of Open Access Journals (Sweden)
Andrea M. Teng
2017-02-01
Full Text Available Abstract Background The World Health Organization recommends all countries consider screening for H. pylori to prevent gastric cancer. We therefore aimed to estimate the cost-effectiveness of a H. pylori serology-based screening program in New Zealand, a country that includes population groups with relatively high gastric cancer rates. Methods A Markov model was developed using life-tables and morbidity data from a national burden of disease study. The modelled screening program reduced the incidence of non-cardia gastric cancer attributable to H. pylori, if infection was identified by serology screening, and for the population expected to be reached by the screening program. A health system perspective was taken and detailed individual-level costing data was used. Results For adults aged 25–69 years old, nation-wide screening for H. pylori was found to have an incremental cost of US$196 million (95% uncertainty interval [95% UI]: $182–$211 million with health gains of 14,200 QALYs (95% UI: 5,100–26,300. Cost per QALY gained was US$16,500 ($7,600–$38,400 in the total population and 17% (6%-29% of future gastric cancer cases could be averted with lifetime follow-up. A targeted screening program for Māori only (indigenous population, was more cost-effective at US$8,000 ($3,800–$18,500 per QALY. Conclusions This modeling study found that H. pylori screening was likely to be cost-effective in this high-income country, particularly for the indigenous population. While further research is needed to help clarify the precise benefits, costs and adverse effects of such screening programs, there seems a reasonable case for policy-makers to give pilot programs consideration, particularly for any population groups with relatively elevated rates of gastric cancer.
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Optimal policies for cumulative damage models with maintenance last and first
International Nuclear Information System (INIS)
Zhao, Xufeng; Qian, Cunhua; Nakagawa, Toshio
2013-01-01
From the economical viewpoint of several combined PM policies in reliability theory, this paper takes up a standard cumulative damage model in which the notion of maintenance last is applied, i.e., the unit undergoes preventive maintenances before failure at a planned time T, at a damage level Z, or at a shock number N, whichever occurs last. Expected cost rates are detailedly formulated, and optimal problems of two alternative policies which combine time-based with condition-based preventive maintenances are discussed, i.e., optimal T L ⁎ for N, Z L ⁎ for T, and N L ⁎ for T are rigorously obtained. Comparison methods between such maintenance last and conventional maintenance first are explored. It is determined theoretically and numerically which policy should be adopted, according to the different methods in different cases when the time-based or the condition-based PM policy is optimized.
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Directory of Open Access Journals (Sweden)
Ping Xu
2018-01-01
Full Text Available Public transport plays an important role in the environment. This study established a Spatial Computable General Equilibrium (SCGE model to examine the economic and environmental effects of public transport subsidy policies. The model includes firms, consumers, and traffic modules in one framework. Statistical data from Beijing were used in calibration to obtain benchmark equilibrium. Based on the equilibrium, simulations compared citywide social welfare, jobs-housing spatial population distribution, and environmental outputs under four subsidy policies: fare subsidy, cash grants, road expansion, and public transport speedup. Based on the results regarding the effects of public transport policies, conclusions can be drawn about which policies will have greater overall social influence and should therefore be used.
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King, Roger
2010-01-01
This article analyzes policy convergence and the adoption of globalizing models by higher education states, a process we describe, following Thatcher (2007), as policy internationalization. This refers to processes found in many policy domains and which increasingly are exemplified in tertiary education systems too. The focus is on governmental…
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Optimal lot sizing in screening processes with returnable defective items
Vishkaei, Behzad Maleki; Niaki, S. T. A.; Farhangi, Milad; Rashti, Mehdi Ebrahimnezhad Moghadam
2014-07-01
This paper is an extension of Hsu and Hsu (Int J Ind Eng Comput 3(5):939-948, 2012) aiming to determine the optimal order quantity of product batches that contain defective items with percentage nonconforming following a known probability density function. The orders are subject to 100 % screening process at a rate higher than the demand rate. Shortage is backordered, and defective items in each ordering cycle are stored in a warehouse to be returned to the supplier when a new order is received. Although the retailer does not sell defective items at a lower price and only trades perfect items (to avoid loss), a higher holding cost incurs to store defective items. Using the renewal-reward theorem, the optimal order and shortage quantities are determined. Some numerical examples are solved at the end to clarify the applicability of the proposed model and to compare the new policy to an existing one. The results show that the new policy provides better expected profit per time.
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Empirical study of supervised gene screening
Directory of Open Access Journals (Sweden)
Ma Shuangge
2006-12-01
Full Text Available Abstract Background Microarray studies provide a way of linking variations of phenotypes with their genetic causations. Constructing predictive models using high dimensional microarray measurements usually consists of three steps: (1 unsupervised gene screening; (2 supervised gene screening; and (3 statistical model building. Supervised gene screening based on marginal gene ranking is commonly used to reduce the number of genes in the model building. Various simple statistics, such as t-statistic or signal to noise ratio, have been used to rank genes in the supervised screening. Despite of its extensive usage, statistical study of supervised gene screening remains scarce. Our study is partly motivated by the differences in gene discovery results caused by using different supervised gene screening methods. Results We investigate concordance and reproducibility of supervised gene screening based on eight commonly used marginal statistics. Concordance is assessed by the relative fractions of overlaps between top ranked genes screened using different marginal statistics. We propose a Bootstrap Reproducibility Index, which measures reproducibility of individual genes under the supervised screening. Empirical studies are based on four public microarray data. We consider the cases where the top 20%, 40% and 60% genes are screened. Conclusion From a gene discovery point of view, the effect of supervised gene screening based on different marginal statistics cannot be ignored. Empirical studies show that (1 genes passed different supervised screenings may be considerably different; (2 concordance may vary, depending on the underlying data structure and percentage of selected genes; (3 evaluated with the Bootstrap Reproducibility Index, genes passed supervised screenings are only moderately reproducible; and (4 concordance cannot be improved by supervised screening based on reproducibility.
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Evaluating the mutagenic potential of aerosol organic compounds using informatics-based screening
Decesari, Stefano; Kovarich, Simona; Pavan, Manuela; Bassan, Arianna; Ciacci, Andrea; Topping, David
2018-02-01
Whilst general policy objectives to reduce airborne particulate matter (PM) health effects are to reduce exposure to PM as a whole, emerging evidence suggests that more detailed metrics associating impacts with different aerosol components might be needed. Since it is impossible to conduct toxicological screening on all possible molecular species expected to occur in aerosol, in this study we perform a proof-of-concept evaluation on the information retrieved from in silico toxicological predictions, in which a subset (N = 104) of secondary organic aerosol (SOA) compounds were screened for their mutagenicity potential. An extensive database search showed that experimental data are available for 13 % of the compounds, while reliable predictions were obtained for 82 %. A multivariate statistical analysis of the compounds based on their physico-chemical, structural, and mechanistic properties showed that 80 % of the compounds predicted as mutagenic were grouped into six clusters, three of which (five-membered lactones from monoterpene oxidation, oxygenated multifunctional compounds from substituted benzene oxidation, and hydroperoxides from several precursors) represent new candidate groups of compounds for future toxicological screenings. These results demonstrate that coupling model-generated compositions to in silico toxicological screening might enable more comprehensive exploration of the mutagenic potential of specific SOA components.
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Gnansounou, Edgard
2018-04-01
This study revisited the fundamentals of allocation to joint products and proposed new models for allocating common greenhouse gases emissions among coproducts of biorefineries. These emissions may account for more than 80% of the total emissions of greenhouse gases of the biorefineries. The proposed models optimize the reward of coproducts for their compliance to environmental requirements. They were illustrated by a case study of wheat straw biorefinery built on the literature. Several scenarios were considered with regard to the grain yield, field emissions of greenhouse gases, allocation between grain and straw and policy requirements. The results conform to the expectations and are sensitive to the policy targets and to the environmental performance of the counterpart system. Further research works are necessary to achieve a full application to complex processes. However, the proposed models are promising towards assessing the simultaneous compliance of coproducts of a biorefinery to environment policy requirements. Copyright © 2018 Elsevier Ltd. All rights reserved.
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Directory of Open Access Journals (Sweden)
Somdatta Patra
2017-01-01
Conclusions: The country's national program advocates for opportunistic and targeted screening of women. An understanding of the factors that influences womens' willingness to participate in screening program is essential for the success of such programs. Hence, this study emphasizes the need for dissemination of knowledge about various aspects of cancer cervix which is critical for uptake of any screening program in a developing country.
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MODELING MONETARY POLICY RULES IN THE MENACOUNTRIES: ISSUES AND EVIDENCE
Mohamad Husam Helmi
2011-01-01
This paper estimates the monetary policy reaction function for two sets of MENAcountries: The inflation target countries, (Turkeyand Israel) and the exchange ratetarget countries, (Jordan and Morocco). We motivateour empirical analysis byanalyzing a simple Taylor rule. This model looks atthe effects of inflation andoutput on setting the interest rate by the centralbank. Furthermore, we extendedour model by adding the exchange rate and the foreign interest rate ...
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Directory of Open Access Journals (Sweden)
Philip W. Brownjohn
2017-04-01
Full Text Available Summary: Human stem cell models have the potential to provide platforms for phenotypic screens to identify candidate treatments and cellular pathways involved in the pathogenesis of neurodegenerative disorders. Amyloid precursor protein (APP processing and the accumulation of APP-derived amyloid β (Aβ peptides are key processes in Alzheimer's disease (AD. We designed a phenotypic small-molecule screen to identify modulators of APP processing in trisomy 21/Down syndrome neurons, a complex genetic model of AD. We identified the avermectins, commonly used as anthelmintics, as compounds that increase the relative production of short Aβ peptides at the expense of longer, potentially more toxic peptides. Further studies demonstrated that this effect is not due to an interaction with the core γ-secretase responsible for Aβ production. This study demonstrates the feasibility of phenotypic drug screening in human stem cell models of Alzheimer-type dementia, and points to possibilities for indirectly modulating APP processing, independently of γ-secretase modulation. : In this article, Livesey and colleagues perform a phenotypic drug screen in a human stem cell model of Alzheimer's disease. The anthelminthic avermectins are identified as a family of compounds that increase the production of short Aβ peptides over longer more toxic Aβ forms. The effect is analogous to existing γ-secretase modulators, but is independent of the core γ-secretase complex. Keywords: neural stem cells, Alzheimer's disease, phenotypic screening, iPSCs, human neurons, dementia, Down syndrome, amyloid beta, ivermectin, selamectin
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LENUS (Irish Health Repository)
Buckley, B S
2011-12-12
Background: Gestational diabetes mellitus is a potentially serious condition that affects many pregnancies and its prevalence is increasing. Evidence suggests early detection and treatment improves outcomes, but this is hampered by continued disagreement and inconsistency regarding many aspects of its diagnosis. Methods: The Vitamin D and Lifestyle Intervention for Gestational Diabetes Mellitus Prevention (DALI) research programme aims to promote pan-European standards in the detection and diagnosis of gestational diabetes and to develop effective preventive interventions. To provide an overview of the context within which the programme will be conducted and its findings interpreted, systematic searching and narrative synthesis have been used to identify and review the best available European evidence relating to the prevalence of gestational diabetes, current screening practices and barriers to screening. Results: Prevalence is most often reported as 2-6% of pregnancies. Prevalence may be lower towards the Northern Atlantic seaboard of Europe and higher in the Southern Mediterranean seaboard. Screening practice and policy is inconsistent across Europe, hampered by lack of consensus on testing methods, diagnostic glycaemic thresholds and the value of routine screening. Poor clinician awareness of gestational diabetes, its diagnosis and local clinical guidelines further undermine detection of gestational diabetes. Conclusions: Europe-wide agreement on screening approaches and diagnostic standards for gestational diabetes could lead to better detection and treatment, improved outcomes for women and children and a strengthened evidence base. There is an urgent need for well-designed research that can inform decisions on best practice in gestational diabetes mellitus screening and diagnosis. © 2011 The Authors. Diabetic Medicine© 2011 Diabetes UK.
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A Computational model for compressed sensing RNAi cellular screening
Directory of Open Access Journals (Sweden)
Tan Hua
2012-12-01
Full Text Available Abstract Background RNA interference (RNAi becomes an increasingly important and effective genetic tool to study the function of target genes by suppressing specific genes of interest. This system approach helps identify signaling pathways and cellular phase types by tracking intensity and/or morphological changes of cells. The traditional RNAi screening scheme, in which one siRNA is designed to knockdown one specific mRNA target, needs a large library of siRNAs and turns out to be time-consuming and expensive. Results In this paper, we propose a conceptual model, called compressed sensing RNAi (csRNAi, which employs a unique combination of group of small interfering RNAs (siRNAs to knockdown a much larger size of genes. This strategy is based on the fact that one gene can be partially bound with several small interfering RNAs (siRNAs and conversely, one siRNA can bind to a few genes with distinct binding affinity. This model constructs a multi-to-multi correspondence between siRNAs and their targets, with siRNAs much fewer than mRNA targets, compared with the conventional scheme. Mathematically this problem involves an underdetermined system of equations (linear or nonlinear, which is ill-posed in general. However, the recently developed compressed sensing (CS theory can solve this problem. We present a mathematical model to describe the csRNAi system based on both CS theory and biological concerns. To build this model, we first search nucleotide motifs in a target gene set. Then we propose a machine learning based method to find the effective siRNAs with novel features, such as image features and speech features to describe an siRNA sequence. Numerical simulations show that we can reduce the siRNA library to one third of that in the conventional scheme. In addition, the features to describe siRNAs outperform the existing ones substantially. Conclusions This csRNAi system is very promising in saving both time and cost for large-scale RNAi
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MODELING MONETARY POLICY RULES IN THE MENACOUNTRIES: ISSUES AND EVIDENCE
Directory of Open Access Journals (Sweden)
Mohamad Husam Helmi
2011-07-01
Full Text Available This paper estimates the monetary policy reaction function for two sets of MENAcountries: The inflation target countries, (Turkeyand Israel and the exchange ratetarget countries, (Jordan and Morocco. We motivateour empirical analysis byanalyzing a simple Taylor rule. This model looks atthe effects of inflation andoutput on setting the interest rate by the centralbank. Furthermore, we extendedour model by adding the exchange rate and the foreign interest rate using similarmodel used by Clarida et al (1998 with using GMM estimator.Findings of this study yield some interesting results,all the central banks in thesample uses interest rate smoothing in managing their monetary policy. Inaddition, The Central bank in Turkey, Israel and Morocco focuses on achievinglow level of inflation. On the other hand, the Monetary Authority in Jordan caresabout stabilizing the output gap. Estimating the extended Taylor rule suggests thehighly significant effect of foreign interest rateon setting the interest rate inTurkey. Taken all together, the results lend support to the importance of followinga rule rather than discretionary in reducing the inflation rate and crediblemonetary policy. In addition, the simple Taylor rule can be applied on MENAcountries but it requires some modification such asadding the exchange rate andthe foreign interest rate.
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Advancing LGBT Elder Policy and Support Services: The Massachusetts Model.
Krinsky, Lisa; Cahill, Sean R
2017-12-01
The Massachusetts-based LGBT Aging Project has trained elder service providers in affirming and culturally competent care for LGBT older adults, supported development of LGBT-friendly meal programs, and advanced LGBT equality under aging policy. Working across sectors, this innovative model launched the country's first statewide Legislative Commission on Lesbian, Gay, Bisexual, and Transgender Aging. Advocates are working with policymakers to implement key recommendations, including cultural competency training and data collection in statewide networks of elder services. The LGBT Aging Project's success provides a template for improving services and policy for LGBT older adults throughout the country.
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Seeing through the public health smoke-screen in drug policy.
Csete, Joanne; Wolfe, Daniel
2017-05-01
In deliberations on drug policy in United Nations fora, a consensus has emerged that drug use and drug dependence should be treated primarily as public health concerns rather than as crimes. But what some member states mean by "public health approach" merits scrutiny. Some governments that espouse treating people who use drugs as "patients, not criminals" still subject them to prison-like detention in the name of drug-dependence treatment or otherwise do not take measures to provide scientifically sound treatment and humane social support to those who need them. Even drug treatment courts, which the U.S. and other countries hold up as examples of a public health approach to drug dependence, can serve rather to tighten the hold of the criminal justice sector on concerns that should be addressed in the health sector. The political popularity of demonisation of drugs and visibly repressive approaches is an obvious challenge to leadership for truly health-oriented drug control. This commentary offers some thoughts for judging whether a public health approach is worthy of the name and cautions drug policy reformers not to rely on facile commitments to health approaches that are largely rhetorical or that mask policies and activities not in keeping with good public health practise. Copyright © 2017 Elsevier B.V. All rights reserved.
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Value for money from HPV vaccination and cervical screening
DEFF Research Database (Denmark)
Ashton, Toni; Sopina, Elizaveta (Liza)
2012-01-01
Introduction of human papillomavirus (HPV) vaccination programs raises some important questions about the future organization of cervical screening programs. Two studies - from NZ and Canada - have addressed the question of what combination of vaccination and screening strategies might be most cost......-effective in preventing cervical cancer. Both studies indicate that some modifications to existing screening programs may be desirable as immunized females enter these programs. Variables in HPV vaccination that are likely to be particularly important for determining the future cost-effectiveness of cervical screening...... programs include: vaccine uptake rate, compliance with full doses, timely completion of doses, duration of protection, male vaccination and HPV infection rate. If value for money is to be achieved, it is important that the appropriate data are collected so that policy makers can consider the combined...
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DEFF Research Database (Denmark)
Paci, Eugenio; Lynge, Elsebeth
2012-01-01
To construct a European 'balance sheet' of key outcomes of population-based mammographic breast cancer screening, to inform policy-makers, stakeholders and invited women.......To construct a European 'balance sheet' of key outcomes of population-based mammographic breast cancer screening, to inform policy-makers, stakeholders and invited women....
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Directory of Open Access Journals (Sweden)
Lawrence von Karsa
2015-12-01
Full Text Available In a project coordinated by the International Agency for Research on Cancer (IARC 31 experts from 11 European countries and IARC have developed supplements to the current European guidelines for quality assurance in cervical cancer screening. The supplements take into account the potential of primary testing for human papillomavirus (HPV and vaccination against HPV infection to improve cervical cancer prevention and control and will be published by the European Commission in book format. They include 62 recommendations or conclusions for which the strength of the evidence and the respective recommendations is graded. While acknowledging the available evidence for more efficacious screening using HPV primary testing compared to screening based on cytology, the authors and editors of the supplements emphasize that appropriate policy and programme organization remain essential to achieve an acceptable balance between benefit and harm of any screening or vaccination programme. A summary of the supplements and all of the graded recommendations are presented here in journal format to make key aspects of the updated and expanded guidelines known to a wider professional and scientific community. Keywords: Mass screening, Vaccination, Cervical neoplasms, Human papillomavirus, Evidence-based guidelines, Population-based programme
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Fokom-Domgue, Joël; Vassilakos, Pierre; Petignat, Patrick
2014-08-01
The World Health Organization guidelines for screening and management of cervical precancerous lesions updated in 2013 made an emphasis on the use of the 'screen-and-treat' approach for cervical cancer prevention. In order to facilitate scaling-up in low income settings, most of these screen-and-treat strategies do not involve confirmatory biopsy. This yields a certain rate of overtreatment. In other words, a majority of people undergoing screen-and-treat intervention who are treated does not necessarily benefit from the treatment. Therefore, the issue of potential short term and long term complications of the recommended treatment procedures (cryotherapy and Loop Electrosurgical Excision Procedure) arises. This question has seldom been studied in resource poor countries, particularly in Sub-Saharan Africa where Human Immunodeficiency Virus infection is rampant in an epidemic fashion and where the procreative capacities are socially rewarding for women. We draw the attention of the scientific community and policy makers to the fact that the lack of evidence supporting the safety of these treatment procedures in African populations may have an impact on the acceptability of these strategies and therefore on the effectiveness of screening programs. Copyright © 2014 Elsevier Inc. All rights reserved.
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Directory of Open Access Journals (Sweden)
Badawi A
2012-04-01
Full Text Available Soroush Mortaz*, Christine Wessman*, Ross Duncan, Rachel Gray, Alaa Badawi Office of Biotechnology Genomics and Population Health, Public Health Agency of Canada, Toronto, Ontario, Canada*Both authors contributed equally to this workBackground: Type 2 diabetes mellitus (T2DM is a major global health problem. An estimated 20%–50% of diabetic subjects in Canada are currently undiagnosed, and around 20%–30% have already developed complications. Screening for high blood glucose levels can identify people with prediabetic conditions and permit introduction of timely and effective prevention. This study examines the benefit of screening for impaired fasting glucose (IFG and T2DM. If intervention is introduced at this prediabetic stage, it can be most effective in delaying the onset and complications of T2DM.Methods: Using a Markov model simulation, we compare the cost-effectiveness of screening for prediabetes (IFG and T2DM with the strategy of no screening. An initial cohort of normoglycemic, prediabetic, or undiagnosed diabetic adults with one or more T2DM risk factors was used to model the strategies mentioned over a 10-year period. Subjects without known prediabetes or diabetes are screened every 3 years and persons with prediabetes were tested for diabetes on an annual basis. The model weighs the increase in quality-adjusted life-years (QALYs associated with early detection of prediabetes and earlier diagnosis of T2DM due to lifestyle intervention and early treatment in asymptomatic subjects.Results: Costs for each QALY gained were $2281 for conventional screening compared with $2890 for no screening. Thus, in this base-case analysis, conventional screening with a frequency of once every 3 years was favored over no screening. Furthermore, conventional screening was more favorable compared with no screening over a wide range of willingness-to-pay thresholds. Changing the frequency of screening did not affect the overall results. Screening
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Directory of Open Access Journals (Sweden)
Rosemarie Sadsad
Full Text Available Methicillin-resistant Staphylococcus aureus (MRSA is a major cause of preventable nosocomial infections and is endemic in hospitals worldwide. The effectiveness of infection control policies varies significantly across hospital settings. The impact of the hospital context towards the rate of nosocomial MRSA infections and the success of infection control is understudied. We conducted a modelling study to evaluate several infection control policies in surgical, intensive care, and medical ward specialties, each with distinct ward conditions and policies, of a tertiary public hospital in Sydney, Australia. We reconfirm hand hygiene as the most successful policy and find it to be necessary for the success of other policies. Active screening for MRSA, patient isolation in single-bed rooms, and additional staffing were found to be less effective. Across these ward specialties, MRSA transmission risk varied by 13% and reductions in the prevalence and nosocomial incidence rate of MRSA due to infection control policies varied by up to 45%. Different levels of infection control were required to reduce and control nosocomial MRSA infections for each ward specialty. Infection control policies and policy targets should be specific for the ward and context of the hospital. The model we developed is generic and can be calibrated to represent different ward settings and pathogens transmitted between patients indirectly through health care workers. This can aid the timely and cost effective design of synergistic and context specific infection control policies.
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Model Proposition for the Fiscal Policies Analysis Applied in Economic Field
Directory of Open Access Journals (Sweden)
Larisa Preda
2007-05-01
Full Text Available This paper presents a study about fiscal policy applied in economic development. Correlations between macroeconomics and fiscal indicators signify the first steep in our analysis. Next step is a new model proposal for the fiscal and budgetary choices. This model is applied on the date of the Romanian case.
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An Object-Oriented Information Model for Policy-based Management of Distributed Applications
Diaz, G.; Gay, V.C.J.; Horlait, E.; Hamza, M.H.
2002-01-01
This paper presents an object-oriented information model to support a policy-based management for distributed multimedia applications. The information base contains application-level information about the users, the applications, and their profile. Our Information model is described in details and
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Mapping and modelling ecosystem services for science, policy and practice
Burkhard, B.; Crossman, N.; Nedkov, S.; Petz, K.; Alkemade, R.
2013-01-01
Ecosystem services are a significant research and policy topic and there are many modelling and mapping approaches aimed at understanding the stocks, demands and flows of ecosystem services on different spatial and temporal scales. The integration of geo-biophysical processes and structure
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An applied general equilibrium model for Dutch agribusiness policy analysis
Peerlings, J.
1993-01-01
The purpose of this thesis was to develop a basic static applied general equilibrium (AGE) model to analyse the effects of agricultural policy changes on Dutch agribusiness. In particular the effects on inter-industry transactions, factor demand, income, and trade are of
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Model-Driven Configuration of SELinux Policies
Agreiter, Berthold; Breu, Ruth
The need for access control in computer systems is inherent. However, the complexity to configure such systems is constantly increasing which affects the overall security of a system negatively. We think that it is important to define security requirements on a non-technical level while taking the application domain into respect in order to have a clear and separated view on security configuration (i.e. unblurred by technical details). On the other hand, security functionality has to be tightly integrated with the system and its development process in order to provide comprehensive means of enforcement. In this paper, we propose a systematic approach based on model-driven security configuration to leverage existing operating system security mechanisms (SELinux) for realising access control. We use UML models and develop a UML profile to satisfy these needs. Our goal is to exploit a comprehensive protection mechanism while rendering its security policy manageable by a domain specialist.
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National Environmental Policy Act guidance: A model process
International Nuclear Information System (INIS)
Angle, B.M.; Lockhart, V.A.T.; Sema, B.; Tuott, L.C.; Irving, J.S.
1995-04-01
The ''Model National Environmental Policy Act (NEPA) Process'' includes: References to regulations, guidance documents, and plans; training programs; procedures; and computer databases. Legislative Acts and reference documents from Congress, US Department of Energy, and Lockheed Idaho Technologies Company provide the bases for conducting NEPA at the Idaho National Engineering Laboratory (INEL). Lockheed Idaho Technologies Company (LITCO) NEPA / Permitting Department, the Contractor Environmental Organization (CEO) is responsible for developing and maintaining LITCO NEPA and permitting policies, guidance, and procedures. The CEO develops procedures to conduct environmental evaluations based on NEPA, Council on Environmental Quality (CEQ) regulations, and DOE guidance. This procedure includes preparation or support of environmental checklists, categorical exclusion determinations, environmental assessment determinations, environmental assessments, and environmental impact statements. In addition, the CEO uses this information to train personnel conducting environmental evaluations at the INEL. Streamlining these procedures fosters efficient use of resources, quality documents, and better decisions on proposed actions
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Geddie, Hannah; Dobrow, Mark J; Hoch, Jeffrey S; Rabeneck, Linda
2012-06-01
Health-policy decision making is a complex and dynamic process, for which strong evidentiary support is required. This includes scientifically produced research, as well as information that relates to the context in which the decision takes place. Unlike scientific evidence, this "contextual evidence" is highly variable and often includes information that is not scientifically produced, drawn from sources such as political judgement, program management experience and knowledge, or public values. As the policy decision-making process is variable and difficult to evaluate, it is often unclear how this heterogeneous evidence is identified and incorporated into "evidence-based policy" decisions. Population-based colorectal cancer screening poses an ideal context in which to examine these issues. In Canada, colorectal cancer screening programs have been established in several provinces over the past five years, based on the fecal occult blood test (FOBT) or the fecal immunochemical test. However, as these programs develop, new scientific evidence for screening continues to emerge. Recently published randomized controlled trials suggest that the use of flexible sigmoidoscopy for population-based screening may pose a greater reduction in mortality than the FOBT. This raises the important question of how policy makers will address this evidence, given that screening programs are being established or are already in place. This study will examine these issues prospectively and will focus on how policy makers monitor emerging scientific evidence and how both scientific and contextual evidence are identified and applied for decisions about health system improvement. This study will employ a prospective multiple case study design, involving participants from Ontario, Alberta, Manitoba, Nova Scotia, and Quebec. In each province, data will be collected via document analysis and key informant interviews. Documents will include policy briefs, reports, meeting minutes, media
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Keel, Stuart; Lee, Pei Ying; Scheetz, Jane; Li, Zhixi; Kotowicz, Mark A; MacIsaac, Richard J; He, Mingguang
2018-03-12
The purpose of this study is to evaluate the feasibility and patient acceptability of a novel artificial intelligence (AI)-based diabetic retinopathy (DR) screening model within endocrinology outpatient settings. Adults with diabetes were recruited from two urban endocrinology outpatient clinics and single-field, non-mydriatic fundus photographs were taken and graded for referable DR ( ≥ pre-proliferative DR). Each participant underwent; (1) automated screening model; where a deep learning algorithm (DLA) provided real-time reporting of results; and (2) manual model where retinal images were transferred to a retinal grading centre and manual grading outcomes were distributed to the patient within 2 weeks of assessment. Participants completed a questionnaire on the day of examination and 1-month following assessment to determine overall satisfaction and the preferred model of care. In total, 96 participants were screened for DR and the mean assessment time for automated screening was 6.9 minutes. Ninety-six percent of participants reported that they were either satisfied or very satisfied with the automated screening model and 78% reported that they preferred the automated model over manual. The sensitivity and specificity of the DLA for correct referral was 92.3% and 93.7%, respectively. AI-based DR screening in endocrinology outpatient settings appears to be feasible and well accepted by patients.
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Wang, Ke-Sheng; Liu, Xuefeng; Ategbole, Muyiwa; Xie, Xin; Liu, Ying; Xu, Chun; Xie, Changchun; Sha, Zhanxin
2017-09-27
Objective: Screening for colorectal cancer (CRC) can reduce disease incidence, morbidity, and mortality. However, few studies have investigated the urban-rural differences in social and behavioral factors influencing CRC screening. The objective of the study was to investigate the potential factors across urban-rural groups on the usage of CRC screening. Methods: A total of 38,505 adults (aged ≥40 years) were selected from the 2009 California Health Interview Survey (CHIS) data - the latest CHIS data on CRC screening. The weighted generalized linear mixed-model (WGLIMM) was used to deal with this hierarchical structure data. Weighted simple and multiple mixed logistic regression analyses in SAS ver. 9.4 were used to obtain the odds ratios (ORs) and their 95% confidence intervals (CIs). Results: The overall prevalence of CRC screening was 48.1% while the prevalence in four residence groups - urban, second city, suburban, and town/rural, were 45.8%, 46.9%, 53.7% and 50.1%, respectively. The results of WGLIMM analysis showed that there was residence effect (pregression analysis revealed that age, race, marital status, education level, employment stats, binge drinking, and smoking status were associated with CRC screening (p<0.05). Stratified by residence regions, age and poverty level showed associations with CRC screening in all four residence groups. Education level was positively associated with CRC screening in second city and suburban. Infrequent binge drinking was associated with CRC screening in urban and suburban; while current smoking was a protective factor in urban and town/rural groups. Conclusions: Mixed models are useful to deal with the clustered survey data. Social factors and behavioral factors (binge drinking and smoking) were associated with CRC screening and the associations were affected by living areas such as urban and rural regions. Creative Commons Attribution License
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A Computable OLG Model for Gender and Growth Policy Analysis
Pierre-Richard Agénor
2012-01-01
This paper develops a computable Overlapping Generations (OLG) model for gender and growth policy analysis. The model accounts for human and physical capital accumulation (both public and private), intra- and inter-generational health persistence, fertility choices, and women's time allocation between market work, child rearing, and home production. Bargaining between spouses and gender bias, in the form of discrimination in the work place and mothers' time allocation between daughters and so...
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Examining Policies to Reduce Homelessness Using a General Equilibrium Model of the Housing Market
Mansur, Erin; Quigley, John M.; Raphael, Steven; Smolensky, Eugene
2003-01-01
In this paper, we use a general equilibrium simulation model to assess the potential impacts on homelessness of various housing-market policy interventions. We calibrate the model to the four largest metropolitan areas in California. We explore the welfare con- sequences and the effects on homelessness of three housing-market policy interventions: extending housing vouchers to all low-income households, subsidizing all landlords, and subsidizing those landlords who supply low-income housing. ...
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Yazaydin, A Ozgür; Snurr, Randall Q; Park, Tae-Hong; Koh, Kyoungmoo; Liu, Jian; Levan, M Douglas; Benin, Annabelle I; Jakubczak, Paulina; Lanuza, Mary; Galloway, Douglas B; Low, John J; Willis, Richard R
2009-12-30
A diverse collection of 14 metal-organic frameworks (MOFs) was screened for CO(2) capture from flue gas using a combined experimental and modeling approach. Adsorption measurements are reported for the screened MOFs at room temperature up to 1 bar. These data are used to validate a generalized strategy for molecular modeling of CO(2) and other small molecules in MOFs. MOFs possessing a high density of open metal sites are found to adsorb significant amounts of CO(2) even at low pressure. An excellent correlation is found between the heat of adsorption and the amount of CO(2) adsorbed below 1 bar. Molecular modeling can aid in selection of adsorbents for CO(2) capture from flue gas by screening a large number of MOFs.
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Periwal, Vinita; Rajappan, Jinuraj K; Jaleel, Abdul Uc; Scaria, Vinod
2011-11-18
Tuberculosis is a contagious disease caused by Mycobacterium tuberculosis (Mtb), affecting more than two billion people around the globe and is one of the major causes of morbidity and mortality in the developing world. Recent reports suggest that Mtb has been developing resistance to the widely used anti-tubercular drugs resulting in the emergence and spread of multi drug-resistant (MDR) and extensively drug-resistant (XDR) strains throughout the world. In view of this global epidemic, there is an urgent need to facilitate fast and efficient lead identification methodologies. Target based screening of large compound libraries has been widely used as a fast and efficient approach for lead identification, but is restricted by the knowledge about the target structure. Whole organism screens on the other hand are target-agnostic and have been now widely employed as an alternative for lead identification but they are limited by the time and cost involved in running the screens for large compound libraries. This could be possibly be circumvented by using computational approaches to prioritize molecules for screening programmes. We utilized physicochemical properties of compounds to train four supervised classifiers (Naïve Bayes, Random Forest, J48 and SMO) on three publicly available bioassay screens of Mtb inhibitors and validated the robustness of the predictive models using various statistical measures. This study is a comprehensive analysis of high-throughput bioassay data for anti-tubercular activity and the application of machine learning approaches to create target-agnostic predictive models for anti-tubercular agents.
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Directory of Open Access Journals (Sweden)
Periwal Vinita
2011-11-01
Full Text Available Abstract Background Tuberculosis is a contagious disease caused by Mycobacterium tuberculosis (Mtb, affecting more than two billion people around the globe and is one of the major causes of morbidity and mortality in the developing world. Recent reports suggest that Mtb has been developing resistance to the widely used anti-tubercular drugs resulting in the emergence and spread of multi drug-resistant (MDR and extensively drug-resistant (XDR strains throughout the world. In view of this global epidemic, there is an urgent need to facilitate fast and efficient lead identification methodologies. Target based screening of large compound libraries has been widely used as a fast and efficient approach for lead identification, but is restricted by the knowledge about the target structure. Whole organism screens on the other hand are target-agnostic and have been now widely employed as an alternative for lead identification but they are limited by the time and cost involved in running the screens for large compound libraries. This could be possibly be circumvented by using computational approaches to prioritize molecules for screening programmes. Results We utilized physicochemical properties of compounds to train four supervised classifiers (Naïve Bayes, Random Forest, J48 and SMO on three publicly available bioassay screens of Mtb inhibitors and validated the robustness of the predictive models using various statistical measures. Conclusions This study is a comprehensive analysis of high-throughput bioassay data for anti-tubercular activity and the application of machine learning approaches to create target-agnostic predictive models for anti-tubercular agents.
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Roy, Kunal; Mitra, Indrani
2011-07-01
Quantitative structure-activity relationships (QSARs) have important applications in drug discovery research, environmental fate modeling, property prediction, etc. Validation has been recognized as a very important step for QSAR model development. As one of the important objectives of QSAR modeling is to predict activity/property/toxicity of new chemicals falling within the domain of applicability of the developed models and QSARs are being used for regulatory decisions, checking reliability of the models and confidence of their predictions is a very important aspect, which can be judged during the validation process. One prime application of a statistically significant QSAR model is virtual screening for molecules with improved potency based on the pharmacophoric features and the descriptors appearing in the QSAR model. Validated QSAR models may also be utilized for design of focused libraries which may be subsequently screened for the selection of hits. The present review focuses on various metrics used for validation of predictive QSAR models together with an overview of the application of QSAR models in the fields of virtual screening and focused library design for diverse series of compounds with citation of some recent examples.
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Ozcelikkale, Altug; Moon, Hye-Ran; Linnes, Michael; Han, Bumsoo
2017-09-01
Advances in nanotechnology have enabled numerous types of nanoparticles (NPs) to improve drug delivery to tumors. While many NP systems have been proposed, their clinical translation has been less than anticipated primarily due to failure of current preclinical evaluation techniques to adequately model the complex interactions between the NP and physiological barriers of tumor microenvironment. This review focuses on microfluidic tumor models for characterization of delivery efficacy and toxicity of cancer nanomedicine. Microfluidics offer significant advantages over traditional macroscale cell cultures by enabling recapitulation of tumor microenvironment through precise control of physiological cues such as hydrostatic pressure, shear stress, oxygen, and nutrient gradients. Microfluidic systems have recently started to be adapted for screening of drugs and NPs under physiologically relevant settings. So far the two primary application areas of microfluidics in this area have been high-throughput screening using traditional culture settings such as single cells or multicellular tumor spheroids, and mimicry of tumor microenvironment for study of cancer-related cell-cell and cell-matrix interactions. These microfluidic technologies are also useful in modeling specific steps in NP delivery to tumor and characterize NP transport properties and outcomes by systematic variation of physiological conditions. Ultimately, it will be possible to design drug-screening platforms uniquely tailored for individual patient physiology using microfluidics. These in vitro models can contribute to development of precision medicine by enabling rapid and patient-specific evaluation of cancer nanomedicine. WIREs Nanomed Nanobiotechnol 2017, 9:e1460. doi: 10.1002/wnan.1460 For further resources related to this article, please visit the WIREs website. © 2017 Wiley Periodicals, Inc.
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Debates—Perspectives on socio-hydrology: Modeling flood risk as a public policy problem
Gober, Patricia; Wheater, Howard S.
2015-06-01
Socio-hydrology views human activities as endogenous to water system dynamics; it is the interaction between human and biophysical processes that threatens the viability of current water systems through positive feedbacks and unintended consequences. Di Baldassarre et al. implement socio-hydrology as a flood risk problem using the concept of social memory as a vehicle to link human perceptions to flood damage. Their mathematical model has heuristic value in comparing potential flood damages in green versus technological societies. It can also support communities in exploring the potential consequences of policy decisions and evaluating critical policy tradeoffs, for example, between flood protection and economic development. The concept of social memory does not, however, adequately capture the social processes whereby public perceptions are translated into policy action, including the pivotal role played by the media in intensifying or attenuating perceived flood risk, the success of policy entrepreneurs in keeping flood hazard on the public agenda during short windows of opportunity for policy action, and different societal approaches to managing flood risk that derive from cultural values and economic interests. We endorse the value of seeking to capture these dynamics in a simplified conceptual framework, but favor a broader conceptualization of socio-hydrology that includes a knowledge exchange component, including the way modeling insights and scientific results are communicated to floodplain managers. The social processes used to disseminate the products of socio-hydrological research are as important as the research results themselves in determining whether modeling is used for real-world decision making.
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Directory of Open Access Journals (Sweden)
Aymeric Ousset
2018-03-01
Full Text Available The evaluation of drug–polymer miscibility in the early phase of drug development is essential to ensure successful amorphous solid dispersion (ASD manufacturing. This work investigates the comparison of thermodynamic models, conventional experimental screening methods (solvent casting, quench cooling, and a novel atomization screening device based on their ability to predict drug–polymer miscibility, solid state properties (Tg value and width, and adequate polymer selection during the development of spray-dried amorphous solid dispersions (SDASDs. Binary ASDs of four drugs and seven polymers were produced at 20:80, 40:60, 60:40, and 80:20 (w/w. Samples were systematically analyzed using modulated differential scanning calorimetry (mDSC and X-ray powder diffraction (XRPD. Principal component analysis (PCA was used to qualitatively assess the predictability of screening methods with regards to SDASD development. Poor correlation was found between theoretical models and experimentally-obtained results. Additionally, the limited ability of usual screening methods to predict the miscibility of SDASDs did not guarantee the appropriate selection of lead excipient for the manufacturing of robust SDASDs. Contrary to standard approaches, our novel screening device allowed the selection of optimal polymer and drug loading and established insight into the final properties and performance of SDASDs at an early stage, therefore enabling the optimization of the scaled-up late-stage development.
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International Nuclear Information System (INIS)
Oblow, E.M.; Perey, F.G.
1984-01-01
A comprehensive rigorous theory is developed for screening sensitivity coefficients in largescale modeling applications. The theory uses Bayesian inference and group theory to establish a probabilistic framework for solving an underdetermined system of linear equations. The underdetermined problem is directly related to statistical screening sensitivity theory as developed in recent years. Several examples of the new approach to screening are worked out in detail and comparisons are made with statistical approaches to the problem. The drawbacks of these latter methods are discussed at some length
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Mandelblatt, Jeanne S; Stout, Natasha K; Schechter, Clyde B; van den Broek, Jeroen J; Miglioretti, Diana L; Krapcho, Martin; Trentham-Dietz, Amy; Munoz, Diego; Lee, Sandra J; Berry, Donald A; van Ravesteyn, Nicolien T; Alagoz, Oguzhan; Kerlikowske, Karla; Tosteson, Anna N A; Near, Aimee M; Hoeffken, Amanda; Chang, Yaojen; Heijnsdijk, Eveline A; Chisholm, Gary; Huang, Xuelin; Huang, Hui; Ergun, Mehmet Ali; Gangnon, Ronald; Sprague, Brian L; Plevritis, Sylvia; Feuer, Eric; de Koning, Harry J; Cronin, Kathleen A
2016-02-16
Controversy persists about optimal mammography screening strategies. To evaluate screening outcomes, taking into account advances in mammography and treatment of breast cancer. Collaboration of 6 simulation models using national data on incidence, digital mammography performance, treatment effects, and other-cause mortality. United States. Average-risk U.S. female population and subgroups with varying risk, breast density, or comorbidity. Eight strategies differing by age at which screening starts (40, 45, or 50 years) and screening interval (annual, biennial, and hybrid [annual for women in their 40s and biennial thereafter]). All strategies assumed 100% adherence and stopped at age 74 years. Benefits (breast cancer-specific mortality reduction, breast cancer deaths averted, life-years, and quality-adjusted life-years); number of mammograms used; harms (false-positive results, benign biopsies, and overdiagnosis); and ratios of harms (or use) and benefits (efficiency) per 1000 screens. Biennial strategies were consistently the most efficient for average-risk women. Biennial screening from age 50 to 74 years avoided a median of 7 breast cancer deaths versus no screening; annual screening from age 40 to 74 years avoided an additional 3 deaths, but yielded 1988 more false-positive results and 11 more overdiagnoses per 1000 women screened. Annual screening from age 50 to 74 years was inefficient (similar benefits, but more harms than other strategies). For groups with a 2- to 4-fold increased risk, annual screening from age 40 years had similar harms and benefits as screening average-risk women biennially from 50 to 74 years. For groups with moderate or severe comorbidity, screening could stop at age 66 to 68 years. Other imaging technologies, polygenic risk, and nonadherence were not considered. Biennial screening for breast cancer is efficient for average-risk populations. Decisions about starting ages and intervals will depend on population characteristics and the
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Screening for gestational diabetes mellitus by a model based on risk indicators
DEFF Research Database (Denmark)
Jensen, Dorte Møller; Mølsted-Pedersen, Lars; Beck-Nielsen, Henning
2003-01-01
OBJECTIVE: This study was performed to prospectively evaluate a screening model for gestational diabetes mellitus on the basis of clinical risk indicators. STUDY DESIGN: In a prospective multicenter study with 5235 consecutive pregnant women, diagnostic testing with a 2-hour 75-g oral glucose...... of the results from tested women to the whole group in question, a 2.4% prevalence of gestational diabetes mellitus was calculated. Sensitivity and specificity of the model was 80.6 (73.7-87.6) and 64.8 (63.5-66.1), respectively (95% CIs). CONCLUSION: Under ideal conditions, sensitivity of the model...
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de Graaff, Barbara; Si, Lei; Neil, Amanda L; Yee, Kwang Chien; Sanderson, Kristy; Gurrin, Lyle C; Palmer, Andrew J
2017-03-01
HFE-associated haemochromatosis, the most common monogenic disorder amongst populations of northern European ancestry, is characterised by iron overload. Excess iron is stored in parenchymal tissues, leading to morbidity and mortality. Population screening programmes are likely to improve early diagnosis, thereby decreasing associated disease. Our aim was to develop and validate a health economics model of screening using utilities and costs from a haemochromatosis cohort. A state-transition model was developed with Markov states based on disease severity. Australian males (aged 30 years) and females (aged 45 years) of northern European ancestry were the target populations. The screening strategy was the status quo approach in Australia; the model was run over a lifetime horizon. Costs were estimated from the government perspective and reported in 2015 Australian dollars ($A); costs and quality-adjusted life-years (QALYs) were discounted at 5% annually. Model validity was assessed using goodness-of-fit analyses. Second-order Monte-Carlo simulation was used to account for uncertainty in multiple parameters. For validity, the model reproduced mortality, life expectancy (LE) and prevalence rates in line with published data. LE for C282Y homozygote males and females were 49.9 and 40.2 years, respectively, slightly lower than population rates. Mean (95% confidence interval) QALYS were 15.7 (7.7-23.7) for males and 14.4 (6.7-22.1) for females. Mean discounted lifetime costs for C282Y homozygotes were $A22,737 (3670-85,793) for males and $A13,840 (1335-67,377) for females. Sensitivity analyses revealed discount rates and prevalence had the greatest impacts on outcomes. We have developed a transparent, validated health economics model of C282Y homozygote haemochromatosis. The model will be useful to decision makers to identify cost-effective screening strategies.
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Generating WS-SecurityPolicy documents via security model transformation
DEFF Research Database (Denmark)
Jensen, Meiko
2009-01-01
When SOA-based business processes are to be enhanced with security properties, the model-driven business process development approach enables an easier and more reliable security definition compared to manually crafting the security realizations afterwards. In this paper, we outline an appropriat...... security model definition and transformation approach, targeting the WS-SecurityPolicy and WS-BPEL specifications, in order to enable a Web-Service-based secure business process development.......When SOA-based business processes are to be enhanced with security properties, the model-driven business process development approach enables an easier and more reliable security definition compared to manually crafting the security realizations afterwards. In this paper, we outline an appropriate...
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Cash Management Policies By Evolutionary Models: A Comparison Using The MILLER-ORR Model
Directory of Open Access Journals (Sweden)
Marcelo Botelho da Costa Moraes
2013-10-01
Full Text Available This work aims to apply genetic algorithms (GA and particle swarm optimization (PSO to managing cash balance, comparing performance results between computational models and the Miller-Orr model. Thus, the paper proposes the application of computational evolutionary models to minimize the total cost of cash balance maintenance, obtaining the parameters for a cash management policy, using assumptions presented in the literature, considering the cost of maintenance and opportunity for cost of cash. For such, we developed computational experiments from cash flows simulated to implement the algorithms. For a control purpose, an algorithm has been developed that uses the Miller-Orr model defining the lower bound parameter, which is not obtained by the original model. The results indicate that evolutionary algorithms present better results than the Miller-Orr model, with prevalence for PSO algorithm in results.
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Screening for breast cancer with mammography
DEFF Research Database (Denmark)
Gøtzsche, Peter C; Nielsen, Margrethe
2009-01-01
BACKGROUND: A variety of estimates of the benefits and harms of mammographic screening for breast cancer have been published and national policies vary. OBJECTIVES: To assess the effect of screening for breast cancer with mammography on mortality and morbidity. SEARCH STRATEGY: We searched Pub...... excluded a biased trial and included 600,000 women in the analyses. Three trials with adequate randomisation did not show a significant reduction in breast cancer mortality at 13 years (relative risk (RR) 0.90, 95% confidence interval (CI) 0.79 to 1.02); four trials with suboptimal randomisation showed...... a significant reduction in breast cancer mortality with an RR of 0.75 (95% CI 0.67 to 0.83). The RR for all seven trials combined was 0.81 (95% CI 0.74 to 0.87). We found that breast cancer mortality was an unreliable outcome that was biased in favour of screening, mainly because of differential...
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Model projections and policy reviews for energy saving in China's service sector
International Nuclear Information System (INIS)
Zhang, Lin
2013-01-01
Energy efficiency of buildings in the service sector is becoming increasingly important in China due to the structural shift of the economy from industry to services. This paper employs a bottom-up cohort model to simulate current energy saving policies and to make projections for future energy use and CO 2 emissions for the period 2000–2030 in the Chinese service sector. The analysis shows that energy demand in the service sector will approximately triple in 2030, far beyond the target of quadrupling GDP while only doubling energy use. However, it is feasible to achieve the target of emission reduction by 40% in 2020 even under the poor state of compliance rate of building standard. This paper also highlights four crucial aspects of designing optimal energy saving policies for China's service sector based on the model results. - Highlights: • Government energy saving target cannot realize with current policies in services. • Energy savings policies for new buildings are crucial than building retrofitting. • Cooling energy use increases significantly to reach equal weight as heating. • CO 2 tax can contribute to change in fuel mix, and thus emission reductions. • Low compliance rate limits further energy saving, hence green fund is required
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Directory of Open Access Journals (Sweden)
James Kingsley
Full Text Available Inadequate bowel preparation during screening colonoscopy necessitates repeating colonoscopy. Studies suggest inadequate bowel preparation rates of 20-60%. This increases the cost of colonoscopy for our society.The aim of this study is to determine the impact of inadequate bowel preparation rate on the cost effectiveness of colonoscopy compared to other screening strategies for colorectal cancer (CRC.A microsimulation model of CRC screening strategies for the general population at average risk for CRC. The strategies include fecal immunochemistry test (FIT every year, colonoscopy every ten years, sigmoidoscopy every five years, or stool DNA test every 3 years. The screening could be performed at private practice offices, outpatient hospitals, and ambulatory surgical centers.At the current assumed inadequate bowel preparation rate of 25%, the cost of colonoscopy as a screening strategy is above society's willingness to pay (<$50,000/QALY. Threshold analysis demonstrated that an inadequate bowel preparation rate of 13% or less is necessary before colonoscopy is considered more cost effective than FIT. At inadequate bowel preparation rates of 25%, colonoscopy is still more cost effective compared to sigmoidoscopy and stool DNA test. Sensitivity analysis of all inputs adjusted by ±10% showed incremental cost effectiveness ratio values were influenced most by the specificity, adherence, and sensitivity of FIT and colonoscopy.Screening colonoscopy is not a cost effective strategy when compared with fecal immunochemical test, as long as the inadequate bowel preparation rate is greater than 13%.
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Yang, Muer; Fry, Michael J; Raikhelkar, Jayashree; Chin, Cynthia; Anyanwu, Anelechi; Brand, Jordan; Scurlock, Corey
2013-02-01
To develop queuing and simulation-based models to understand the relationship between ICU bed availability and operating room schedule to maximize the use of critical care resources and minimize case cancellation while providing equity to patients and surgeons. Retrospective analysis of 6-month unit admission data from a cohort of cardiothoracic surgical patients, to create queuing and simulation-based models of ICU bed flow. Three different admission policies (current admission policy, shortest-processing-time policy, and a dynamic policy) were then analyzed using simulation models, representing 10 yr worth of potential admissions. Important output data consisted of the "average waiting time," a proxy for unit efficiency, and the "maximum waiting time," a surrogate for patient equity. A cardiothoracic surgical ICU in a tertiary center in New York, NY. Six hundred thirty consecutive cardiothoracic surgical patients admitted to the cardiothoracic surgical ICU. None. Although the shortest-processing-time admission policy performs best in terms of unit efficiency (0.4612 days), it did so at expense of patient equity prolonging surgical waiting time by as much as 21 days. The current policy gives the greatest equity but causes inefficiency in unit bed-flow (0.5033 days). The dynamic policy performs at a level (0.4997 days) 8.3% below that of the shortest-processing-time in average waiting time; however, it balances this with greater patient equity (maximum waiting time could be shortened by 4 days compared to the current policy). Queuing theory and computer simulation can be used to model case flow through a cardiothoracic operating room and ICU. A dynamic admission policy that looks at current waiting time and expected ICU length of stay allows for increased equity between patients with only minimum losses of efficiency. This dynamic admission policy would seem to be a superior in maximizing case-flow. These results may be generalized to other surgical ICUs.
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Social policies and activation in the Scandinavian welfare model: the case of Denmark
DEFF Research Database (Denmark)
Andersen, Torben M.
countries been able to reconcile social objectives with a high employment level? It is argued that the Scandinavian welfare model has a strong employment focus both because it is an important element in social policy based on social inclusion, but also because a collective welfare arrangement is only...... financially viable if (private) employment is sufficiently high. To ensure this, the social safety net includes a number of employment conditionalities (active labour market policies/workfare) to balance income protection with an employment focus. These policies are discussed using Denmark as an example...
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Petry, Karl Ulrich; Barth, Cordula; Wasem, Jürgen; Neumann, Anja
2017-05-01
We modelled human papilloma virus (HPV) primary screening scenarios compared with Pap cytology to evaluate clinical effectiveness and projected annual costs in Germany. A Markov cohort model was built to compare the budget impact of annual Pap cytology with different 5-yearly HPV screening scenarios: (1) a positive HPV test followed by Pap cytology; (2) a positive HPV test followed by p16/Ki-67 dual-stained cytology; (3) a positive HPV test followed by colposcopy if HPV-16/18-positive or p16/Ki-67 dual-stained cytology if positive for other subtypes; (4) co-testing with HPV and Pap. Screening scenarios were based on a 10-year horizon. All HPV screening scenarios in the model were associated with fewer deaths from missed diagnosis of cervical cancer compared with Pap screening; 10-year totals n=172-344 (1.5-3 per 100,000) versus n=477 (4.1 per 100,000), respectively. Total annual costs were lower with HPV screening than Pap cytology. The projected average annual cost for HPV screening ranged from €117 million to €136 million compared with €177 million for Pap screening, representing annual savings of €41-60 million. The greatest clinical impact was achieved with primary HPV screening (with genotyping) followed by colposcopy for HPV 16/18-positive women or p16/Ki-67 dual-stained cytology for women positive for other HPV subtypes. Screening strategies including primary HPV testing for high-risk subtypes (HPV-16/18) in conjunction with p16/Ki-67 dual-stained cytology can improve the detection of cervical cancer at a lower total annual cost than conventional Pap cytology screening. Copyright © 2017. Published by Elsevier B.V.
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Nakagawa, Toshio
2014-01-01
Exploring random maintenance models, this book provides an introduction to the implementation of random maintenance, and it is one of the first books to be written on this subject. It aims to help readers learn new techniques for applying random policies to actual reliability models, and it provides new theoretical analyses of various models including classical replacement, preventive maintenance and inspection policies. These policies are applied to scheduling problems, backup policies of database systems, maintenance policies of cumulative damage models, and reliability of random redundant systems. Reliability theory is a major concern for engineers and managers, and in light of Japan’s recent earthquake, the reliability of large-scale systems has increased in importance. This also highlights the need for a new notion of maintenance and reliability theory, and how this can practically be applied to systems. Providing an essential guide for engineers and managers specializing in reliability maintenance a...
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Networks and Bargaining in Policy Analysis
DEFF Research Database (Denmark)
Bogason, Peter
2006-01-01
A duscussion of the fight between proponents of rationalistic policy analysis and more political interaction models for policy analysis. The latter group is the foundation for the many network models of policy analysis of today.......A duscussion of the fight between proponents of rationalistic policy analysis and more political interaction models for policy analysis. The latter group is the foundation for the many network models of policy analysis of today....
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International Nuclear Information System (INIS)
Park, Young-Min; Kim, Kwang-Joon
2011-01-01
Piezoelectric exciters have been receiving greater attention recently as a vibration source for tactile feedback in devices with touch screens, such as a mobile phones, in place of DC motors due to lower energy consumption and smaller volume. Their insufficient excitation level, however, still remains a problem. In this paper, dynamic modeling and design improvement of a piezoelectric exciter are presented. The excitation performance is defined as the acceleration response at the center of a touch screen per electric power and to be maximized around 250 Hz where the index finger is most sensitive. The piezoelectric exciter consists of a z-shaped metal beam, a piezoelectric layer on the long horizontal segment and an adhesive layer between the short horizontal segment and the touch screen. Assuming that the piezoelectric exciter is attached onto a rigid ground due to its low mechanical impedance compared with that of the touch screen, the piezoelectric exciter is dynamically modeled by applying Hamilton's principle, where the adhesive layer is treated as a distributed stiffness. The touch screen is modeled approximately as a simply supported beam such that it may have the same fundamental natural frequency and bending stiffness as the screen based on measurements. The performance improvement is focused on the change of five geometric parameters of the piezoelectric exciter: length of the long horizontal segment, thickness of the piezoelectric layer, thickness of the elastic metal layer, width of the beams and tip mass. The procedure to improve the performance of the piezoelectric exciter via dynamic modeling is presented together with experimental results on a prototype. Effectiveness of the design modification and limitations in practice are further discussed as well
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Directory of Open Access Journals (Sweden)
Kinmonth Ann
2009-05-01
Full Text Available Abstract Background The increasing prevalence of type 2 diabetes poses a major public health challenge. Population-based screening and early treatment for type 2 diabetes could reduce this growing burden. However, the benefits of such a strategy remain uncertain. Methods and design The ADDITION-Cambridge study aims to evaluate the effectiveness and cost-effectiveness of (i a stepwise screening strategy for type 2 diabetes; and (ii intensive multifactorial treatment for people with screen-detected diabetes in primary care. 63 practices in the East Anglia region participated. Three undertook the pilot study, 33 were allocated to three groups: no screening (control, screening followed by intensive treatment (IT and screening plus routine care (RC in an unbalanced (1:3:3 randomisation. The remaining 27 practices were randomly allocated to IT and RC. A risk score incorporating routine practice data was used to identify people aged 40–69 years at high-risk of undiagnosed diabetes. In the screening practices, high-risk individuals were invited to take part in a stepwise screening programme. In the IT group, diabetes treatment is optimised through guidelines, target-led multifactorial treatment, audit, feedback, and academic detailing for practice teams, alongside provision of educational materials for newly diagnosed participants. Primary endpoints are modelled cardiovascular risk at one year, and cardiovascular mortality and morbidity at five years after diagnosis of diabetes. Secondary endpoints include all-cause mortality, development of renal and visual impairment, peripheral neuropathy, health service costs, self-reported quality of life, functional status and health utility. Impact of the screening programme at the population level is also assessed through measures of mortality, cardiovascular morbidity, health status and health service use among high-risk individuals. Discussion ADDITION-Cambridge is conducted in a defined high-risk group
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Mutation-Guided Unbiased Modeling of the Fat Sensor GPR119 for High-Yield Agonist Screening
DEFF Research Database (Denmark)
Norn, Christoffer; Pedersen, Maria Hauge; Engelstoft, Maja S.
2015-01-01
and is consistent with the structure-activity relationship for a large no. of AR231453 analogs. Another key property of the refined models is their success in sepg. active ligands from decoys in a large-scale virtual screening. These results demonstrate that mutation-guided receptor modeling can provide predictions...
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Energy Technology Data Exchange (ETDEWEB)
Tsoukos, S; Kateris, A; Kalivas, N; Spyrou, G; Panayiotakis, G [Department of Medical Physics, School of Medicine, University of Patras, 265 00 pAtras (Greece); Kandarakis, I; Gavouras, D [Department of Medical Instrumentation Technology, Technological Educational Institution of Athens (Greece)
1999-12-31
A theoretical model predicting the intensity of light emitted by x-ray imaging phosphor screens per unit of area and time over incident x-ray flux (absolute efficiency) was developed. The model takes into account : A) the structure of the screens which consists of luminescent grains embedded in a binding matrix. B) the direct deposition of energy by x-ray absorption effects.. C) the re-absorption of K fluorescence characteristic x-rays produced when the x-ray energy exceeds the energy of the K absorption edge of the phosphor material. To test the model a set of (Gd,La)2O2S:Tb phosphor screens was prepared by sedimentation in the laboratory. Experimental absolute efficiency data were obtained at x-ray tube voltage range from 40 to 160 kVp. The coincidence between experimental and theoretical results were satisfactory. (authors) 7 refs., 4 figs.
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Private and public eugenics: genetic and screening in India
Gupta, J.A.
2007-01-01
Epidemiologists and geneticists claim that genetics has an increasing role to play in public health policies and programs in the future. Within this perspective, genetic testing and screening are instrumental in avoiding the birth of children with serious, costly or untreatable disorders. This paper
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Screening for Patent Quality : Examination, Fees, and the Courts
Schankerman, Mark; Schütt, Florian
2016-01-01
We develop an integrated framework to study how governments can improve the quality of patent screening. We focus on four key policy instruments: patent office examination, pre- and post-grant fees, and challenges in the courts. We show that there are important complementarities among these
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Competing risks model in screening for preeclampsia by maternal characteristics and medical history.
Wright, David; Syngelaki, Argyro; Akolekar, Ranjit; Poon, Leona C; Nicolaides, Kypros H
2015-07-01
The purpose of this study was to develop a model for preeclampsia based on maternal demographic characteristics and medical history. This was a screening study of 120,492 singleton pregnancies at 11-13 weeks' gestation, including 2704 pregnancies (2.2%) that experienced preeclampsia. A survival-time model for the gestational age at delivery with preeclampsia was developed from variables of maternal characteristics and history. This approach assumes that, if the pregnancy was to continue indefinitely, all women would experience preeclampsia and that whether they do so or not before a specified gestational age depends on competition between delivery before or after development of preeclampsia. A 5-fold cross validation study was conducted to compare the performance of the new model with the National Institute for Health and Clinical Excellence (NICE) guidelines. In the new model, increased risk for preeclampsia, with a consequent shift in the Gaussian distribution of the gestational age at delivery with preeclampsia to the left, is provided by advancing maternal age, increasing weight, Afro-Caribbean and South Asian racial origin, medical history of chronic hypertension, diabetes mellitus and systemic lupus erythematosus or antiphospholipid syndrome, family history and personal history of preeclampsia, and conception by in vitro fertilization. The risk for preeclampsia decreases with increasing maternal height and in parous women with no previous preeclampsia; in the latter, the protective effect, which is related inversely to the interpregnancy interval, persists beyond 15 years. At a screen-positive rate of 11%, as defined by NICE, the new model predicted 40%, 48%, and 54% of cases of total preeclampsia and preeclampsia requiring delivery at preeclampsia. Such estimation of the a priori risk for preeclampsia is an essential first step in the use of Bayes theorem to combine maternal factors with biomarkers for the continuing development of more effective methods of
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Directory of Open Access Journals (Sweden)
Gwenan M. Knight
2016-01-01
Full Text Available The dominant approach to decision-making in public health policy for infectious diseases relies heavily on expert opinion, which often applies empirical evidence to policy questions in a manner that is neither systematic nor transparent. Although systematic reviews are frequently commissioned to inform specific components of policy (such as efficacy, the same process is rarely applied to the full decision-making process. Mathematical models provide a mechanism through which empirical evidence can be methodically and transparently integrated to address such questions. However, such models are often considered difficult to interpret. In addition, models provide estimates that need to be iteratively re-evaluated as new data or considerations arise. Using the case study of a novel diagnostic for tuberculosis, a framework for improved collaboration between public health decision-makers and mathematical modellers that could lead to more transparent and evidence-driven policy decisions for infectious diseases in the future is proposed. The framework proposes that policymakers should establish long-term collaborations with modellers to address key questions, and that modellers should strive to provide clear explanations of the uncertainty of model structure and outputs. Doing so will improve the applicability of models and clarify their limitations when used to inform real-world public health policy decisions.
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Energy Technology Data Exchange (ETDEWEB)
Roman, M., E-mail: Marta.Roman@kreftregisteret.no [Cancer Registry of Norway, Oslo (Norway); Department of Women and Children’s Health, Oslo University Hospital, Oslo (Norway); Skaane, P., E-mail: PERSK@ous-hf.no [Department of Radiology, Oslo University Hospital Ullevaal, University of Oslo, Oslo (Norway); Hofvind, S., E-mail: Solveig.Hofvind@kreftregisteret.no [Cancer Registry of Norway, Oslo (Norway); Oslo and Akershus University College of Applied Sciences, Faculty of Health Science, Oslo (Norway)
2014-09-15
Highlights: • We found variation in early performance measures across screening centres. • Radiologists’ performance may play a key role in the variability. • Potential to improve the effectiveness of breast cancer screening programs. • Continuous surveillance of screening centres and radiologists is essential. - Abstract: Background: Recall for assessment in mammographic screening entails an inevitable number of false-positive screening results. This study aimed to investigate the variation in the cumulative risk of a false positive screening result and the positive predictive value across the screening centres in the Norwegian Breast Cancer Screening Program. Methods: We studied 618,636 women aged 50–69 years who underwent 2,090,575 screening exams (1996–2010. Recall rate, positive predictive value, rate of screen-detected cancer, and the cumulative risk of a false positive screening result, without and with invasive procedures across the screening centres were calculated. Generalized linear models were used to estimate the probability of a false positive screening result and to compute the cumulative false-positive risk for up to ten biennial screening examinations. Results: The cumulative risk of a false-positive screening exam varied from 10.7% (95% CI: 9.4–12.0%) to 41.5% (95% CI: 34.1–48.9%) across screening centres, with a highest to lowest ratio of 3.9 (95% CI: 3.7–4.0). The highest to lowest ratio for the cumulative risk of undergoing an invasive procedure with a benign outcome was 4.3 (95% CI: 4.0–4.6). The positive predictive value of recall varied between 12.0% (95% CI: 11.0–12.9%) and 19.9% (95% CI: 18.3–21.5%), with a highest to lowest ratio of 1.7 (95% CI: 1.5–1.9). Conclusions: A substantial variation in the performance measures across the screening centres in the Norwegian Breast Cancer Screening Program was identified, despite of similar administration, procedures, and quality assurance requirements. Differences in the
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International Nuclear Information System (INIS)
Roman, M.; Skaane, P.; Hofvind, S.
2014-01-01
Highlights: • We found variation in early performance measures across screening centres. • Radiologists’ performance may play a key role in the variability. • Potential to improve the effectiveness of breast cancer screening programs. • Continuous surveillance of screening centres and radiologists is essential. - Abstract: Background: Recall for assessment in mammographic screening entails an inevitable number of false-positive screening results. This study aimed to investigate the variation in the cumulative risk of a false positive screening result and the positive predictive value across the screening centres in the Norwegian Breast Cancer Screening Program. Methods: We studied 618,636 women aged 50–69 years who underwent 2,090,575 screening exams (1996–2010. Recall rate, positive predictive value, rate of screen-detected cancer, and the cumulative risk of a false positive screening result, without and with invasive procedures across the screening centres were calculated. Generalized linear models were used to estimate the probability of a false positive screening result and to compute the cumulative false-positive risk for up to ten biennial screening examinations. Results: The cumulative risk of a false-positive screening exam varied from 10.7% (95% CI: 9.4–12.0%) to 41.5% (95% CI: 34.1–48.9%) across screening centres, with a highest to lowest ratio of 3.9 (95% CI: 3.7–4.0). The highest to lowest ratio for the cumulative risk of undergoing an invasive procedure with a benign outcome was 4.3 (95% CI: 4.0–4.6). The positive predictive value of recall varied between 12.0% (95% CI: 11.0–12.9%) and 19.9% (95% CI: 18.3–21.5%), with a highest to lowest ratio of 1.7 (95% CI: 1.5–1.9). Conclusions: A substantial variation in the performance measures across the screening centres in the Norwegian Breast Cancer Screening Program was identified, despite of similar administration, procedures, and quality assurance requirements. Differences in the
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Bataille, Christopher G. F.
2005-11-01
Are further energy efficiency gains, or more recently greenhouse gas reductions, expensive or cheap? Analysts provide conflicting advice to policy makers based on divergent modelling perspectives, a 'top-down/bottom-up debate' in which economists use equation based models that equilibrate markets by maximizing consumer welfare, and technologists use technology simulation models that minimize the financial cost of providing energy services. This thesis summarizes a long term research project to find a middle ground between these two positions that is more useful to policy makers. Starting with the individual components of a behaviourally realistic and technologically explicit simulation model (ISTUM---Inter Sectoral Technology Use Model), or "hybrid", the individual sectors of the economy are linked using a framework of micro and macro economic feedbacks. These feedbacks are taken from the economic theory that informs the computable general equilibrium (CGE) family of models. Speaking in the languages of both economists and engineers, the resulting "physical" equilibrium model of Canada (CIMS---Canadian Integrated Modeling System), equilibrates energy and end-product markets, including imports and exports, for seven regions and 15 economic sectors, including primary industry, manufacturing, transportation, commerce, residences, governmental infrastructure and the energy supply sectors. Several different policy experiments demonstrate the value-added of the model and how its results compare to top-down and bottom-up practice. In general, the results show that technical adjustments make up about half the response to simulated energy policy, and macroeconomic demand adjustments the other half. Induced technical adjustments predominate with minor policies, while the importance of macroeconomic demand adjustment increases with the strength of the policy. Results are also shown for an experiment to derive estimates of future elasticity of substitution (ESUB) and
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Quarterman, Josh; Kim, Soo Rin; Kim, Pan-Jun; Jin, Yong-Su
2015-01-20
In order to determine beneficial gene deletions for ethanol production by the yeast Saccharomyces cerevisiae, we performed an in silico gene deletion experiment based on a genome-scale metabolic model. Genes coding for two oxidative phosphorylation reactions (cytochrome c oxidase and ubiquinol cytochrome c reductase) were identified by the model-based simulation as potential deletion targets for enhancing ethanol production and maintaining acceptable overall growth rate in oxygen-limited conditions. Since the two target enzymes are composed of multiple subunits, we conducted a genetic screening study to evaluate the in silico results and compare the effect of deleting various portions of the respiratory enzyme complexes. Over two-thirds of the knockout mutants identified by the in silico study did exhibit experimental behavior in qualitative agreement with model predictions, but the exceptions illustrate the limitation of using a purely stoichiometric model-based approach. Furthermore, there was a substantial quantitative variation in phenotype among the various respiration-deficient mutants that were screened in this study, and three genes encoding respiratory enzyme subunits were identified as the best knockout targets for improving hexose fermentation in microaerobic conditions. Specifically, deletion of either COX9 or QCR9 resulted in higher ethanol production rates than the parental strain by 37% and 27%, respectively, with slight growth disadvantages. Also, deletion of QCR6 led to improved ethanol production rate by 24% with no growth disadvantage. The beneficial effects of these gene deletions were consistently demonstrated in different strain backgrounds and with four common hexoses. The combination of stoichiometric modeling and genetic screening using a systematic knockout collection was useful for narrowing a large set of gene targets and identifying targets of interest. Copyright © 2014 Elsevier B.V. All rights reserved.
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Public health advocacy in action: the case of unproven breast cancer screening in Australia.
Johnson, Rebecca S; Croager, Emma J; Kameron, Caitlin B; Pratt, Iain S; Vreugdenburg, Thomas D; Slevin, Terry
2016-09-30
In recent years, nonmammographic breast imaging devices, such as thermography, electrical impedance scanning and elastography, have been promoted directly to consumers, which has captured the attention of governments, researchers and health organisations. These devices are not supported by evidence and risk undermining existing mammographic breast cancer screening services. During a 5-year period, Cancer Council Western Australia (CCWA) used strategic research combined with legal, policy and media advocacy to contest claims that these devices were proven alternatives to mammography for breast cancer screening. The campaign was successful because it had input from people with public health, academic, clinical and legal backgrounds, and took advantage of existing legal and regulatory avenues. CCWA's experience provides a useful advocacy model for public health practitioners who are concerned about unsafe consumer products, unproven medical devices, and misleading health information and advertising.
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Directory of Open Access Journals (Sweden)
Sanjay Basu
2015-05-01
Full Text Available Like a growing number of rapidly developing countries, India has begun to develop a system for large-scale community-based screening for diabetes. We sought to identify the implications of using alternative screening instruments to detect people with undiagnosed type 2 diabetes among diverse populations across India.We developed and validated a microsimulation model that incorporated data from 58 studies from across the country into a nationally representative sample of Indians aged 25-65 y old. We estimated the diagnostic and health system implications of three major survey-based screening instruments and random glucometer-based screening. Of the 567 million Indians eligible for screening, depending on which of four screening approaches is utilized, between 158 and 306 million would be expected to screen as "high risk" for type 2 diabetes, and be referred for confirmatory testing. Between 26 million and 37 million of these people would be expected to meet international diagnostic criteria for diabetes, but between 126 million and 273 million would be "false positives." The ratio of false positives to true positives varied from 3.9 (when using random glucose screening to 8.2 (when using a survey-based screening instrument in our model. The cost per case found would be expected to be from US$5.28 (when using random glucose screening to US$17.06 (when using a survey-based screening instrument, presenting a total cost of between US$169 and US$567 million. The major limitation of our analysis is its dependence on published cohort studies that are unlikely fully to capture the poorest and most rural areas of the country. Because these areas are thought to have the lowest diabetes prevalence, this may result in overestimation of the efficacy and health benefits of screening.Large-scale community-based screening is anticipated to produce a large number of false-positive results, particularly if using currently available survey-based screening
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International Nuclear Information System (INIS)
Wolf, C.
1993-01-01
We study the screening of a central Abelian dyon by a surrounding dyon cloud in a two potential theory of electromagnetism. A generalized formula for the Debye screening length is obtained and a Thomas - Fermi Model for a charged cloud surrounding a central Dyonic Core is studied. 20 refs
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Manning, Matthew; Wong, Gabriel T W; Ransley, Janet; Smith, Christine
2016-06-01
In this paper we capture and synthesize the unique knowledge of experts so that choices regarding policy measures to address methamphetamine consumption and dependency in Australia can be strengthened. We examine perceptions of the: (1) influence of underlying factors that impact on the methamphetamine problem; (2) importance of various models of intervention that have the potential to affect the success of policies; and (3) efficacy of alternative pseudoephedrine policy options. We adopt a multi-criteria decision model to unpack factors that affect decisions made by experts and examine potential variations on weight/preference among groups. Seventy experts from five groups (i.e. academia (18.6%), government and policy (27.1%), health (18.6%), pharmaceutical (17.1%) and police (18.6%)) in Australia participated in the survey. Social characteristics are considered the most important underlying factor, prevention the most effective strategy and Project STOP the most preferred policy option with respect to reducing methamphetamine consumption and dependency in Australia. One-way repeated ANOVAs indicate a statistically significant difference with regards to the influence of underlying factors (F(2.3, 144.5)=11.256, pmethamphetamine consumption and dependency. Most experts support the use of preventative mechanisms to inhibit drug initiation and delayed drug uptake. Compared to other policies, Project STOP (which aims to disrupt the initial diversion of pseudoephedrine) appears to be a more preferable preventative mechanism to control the production and subsequent sale and use of methamphetamine. This regulatory civil law lever engages third parties in controlling drug-related crime. The literature supports third-party partnerships as it engages experts who have knowledge and expertise with respect to prevention and harm minimization. Copyright © 2016 Elsevier B.V. All rights reserved.
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Colorectal cancer screening for average-risk North Americans: an economic evaluation.
Directory of Open Access Journals (Sweden)
Steven J Heitman
Full Text Available BACKGROUND: Colorectal cancer (CRC fulfills the World Health Organization criteria for mass screening, but screening uptake is low in most countries. CRC screening is resource intensive, and it is unclear if an optimal strategy exists. The objective of this study was to perform an economic evaluation of CRC screening in average risk North American individuals considering all relevant screening modalities and current CRC treatment costs. METHODS AND FINDINGS: An incremental cost-utility analysis using a Markov model was performed comparing guaiac-based fecal occult blood test (FOBT or fecal immunochemical test (FIT annually, fecal DNA every 3 years, flexible sigmoidoscopy or computed tomographic colonography every 5 years, and colonoscopy every 10 years. All strategies were also compared to a no screening natural history arm. Given that different FIT assays and collection methods have been previously tested, three distinct FIT testing strategies were considered, on the basis of studies that have reported "low," "mid," and "high" test performance characteristics for detecting adenomas and CRC. Adenoma and CRC prevalence rates were based on a recent systematic review whereas screening adherence, test performance, and CRC treatment costs were based on publicly available data. The outcome measures included lifetime costs, number of cancers, cancer-related deaths, quality-adjusted life-years gained, and incremental cost-utility ratios. Sensitivity and scenario analyses were performed. Annual FIT, assuming mid-range testing characteristics, was more effective and less costly compared to all strategies (including no screening except FIT-high. Among the lifetimes of 100,000 average-risk patients, the number of cancers could be reduced from 4,857 to 1,393 [corrected] and the number of CRC deaths from 1,782 [corrected] to 457, while saving CAN$68 per person. Although screening patients with FIT became more expensive than a strategy of no screening when the
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Intelligent simulation of aquatic environment economic policy coupled ABM and SD models.
Wang, Huihui; Zhang, Jiarui; Zeng, Weihua
2018-03-15
Rapid urbanization and population growth have resulted in serious water shortage and pollution of the aquatic environment, which are important reasons for the complex increase in environmental deterioration in the region. This study examines the environmental consequences and economic impacts of water resource shortages under variant economic policies; however, this requires complex models that jointly consider variant agents and sectors within a systems perspective. Thus, we propose a complex system model that couples multi-agent based models (ABM) and system dynamics (SD) models to simulate the impact of alternative economic policies on water use and pricing. Moreover, this model took the constraint of the local water resources carrying capacity into consideration. Results show that to achieve the 13th Five Year Plan targets in Dianchi, water prices for local residents and industries should rise to 3.23 and 4.99 CNY/m 3 , respectively. The corresponding sewage treatment fees for residents and industries should rise to 1.50 and 2.25 CNY/m 3 , respectively, assuming comprehensive adjustment of industrial structure and policy. At the same time, the local government should exercise fine-scale economic policy combined with emission fees assessed for those exceeding a standard, and collect fines imposed as punishment for enterprises that exceed emission standards. When fines reach 500,000 CNY, the total number of enterprises that exceed emission standards in the basin can be controlled within 1%. Moreover, it is suggested that the volume of water diversion in Dianchi should be appropriately reduced to 3.06×10 8 m 3 . The reduced expense of water diversion should provide funds to use for the construction of recycled water facilities. Then the local rise in the rate of use of recycled water should reach 33%, and 1.4 CNY/m 3 for the price of recycled water could be provided to ensure the sustainable utilization of local water resources. Copyright © 2017 Elsevier B
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Modeling and Simulation of Bus Dispatching Policy for Timed Transfers on Signalized Networks
Cho, Hsun-Jung; Lin, Guey-Shii
2007-12-01
The major work of this study is to formulate the system cost functions and to integrate the bus dispatching policy with signal control. The integrated model mainly includes the flow dispersion model for links, signal control model for nodes, and dispatching control model for transfer terminals. All such models are inter-related for transfer operations in one-center transit network. The integrated model that combines dispatching policies with flexible signal control modes can be applied to assess the effectiveness of transfer operations. It is found that, if bus arrival information is reliable, an early dispatching decision made at the mean bus arrival times is preferable. The costs for coordinated operations with slack times are relatively low at the optimal common headway when applying adaptive route control. Based on such findings, a threshold function of bus headway for justifying an adaptive signal route control under various time values of auto drivers is developed.
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High Throughput Screen for Novel Antimicrobials using a Whole Animal Infection Model
Moy, Terence I.; Conery, Annie L.; Larkins-Ford, Jonah; Wu, Gang; Mazitschek, Ralph; Casadei, Gabriele; Lewis, Kim; Carpenter, Anne E.; Ausubel, Frederick M.
2009-01-01
The nematode Caenorhabditis elegans is a unique whole animal model system for identifying small molecules with in vivo anti-infective properties. C. elegans can be infected with a broad range of human pathogens, including Enterococcus faecalis, an important human nosocomial pathogen with a mortality rate of up to 37% that is increasingly acquiring resistance to antibiotics. Here, we describe an automated, high throughput screen of 37,200 compounds and natural product extracts for those that enhance survival of C. elegans infected with E. faecalis. The screen uses a robot to accurately dispense live, infected animals into 384-well plates, and automated microscopy and image analysis to generate quantitative, high content data. We identified 28 compounds and extracts that were not previously reported to have antimicrobial properties, including 6 structural classes that cure infected C. elegans animals but do not affect the growth of the pathogen in vitro, thus acting by a mechanism of action distinct from antibiotics currently in clinical use. Our versatile and robust screening system can be easily adapted for other whole animal assays to probe a broad range of biological processes. PMID:19572548
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Econometric Model of Rice Policy Based On Presidential Instruction
Abadi Sembiring, Surya; Hutauruk, Julia
2018-01-01
The objective of research is to build an econometric model based on Presidential Instruction rice policy. The data was monthly time series from March 2005 to September 2009. Rice policy model specification using simultaneous equation, consisting of 14 structural equations and four identity equation, which was estimated using Two Stages Least Squares (2SLS) method. The results show that: (1) an increase of government purchasing price of dried harvest paddy has a positive impact on to increase in total rice production and community rice stock, (2) an increase community rice stock lead to decrease the rice imports, (3) an increase of the realization of the distribution of subsidized ZA fertilizers and the realization of the distribution of subsidized NPK fertilizers has a positive impact on to increase in total rice production and community rice stock and to reduce rice imports, (4) the price of the dried harvest paddy is highly responsive to the water content of dried harvest paddy both the short run and long run, (5) the quantity of rice imported is highly responsive to the imported rice price, both short run and long run.
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The dynamic macroeconomic effects of tax policy in an overlapping generations model
Heijdra, BJ; Ligthart, JE
2000-01-01
The paper studies the dynamic allocation effects of tax policy within the context of an overlapping-generations model of the Blanchard-Yaari type. The model is extended to allow for endogenous labour supply and three tax instruments, viz. a capital tax, labour income tax, and consumption tax. Both
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Cognitive screening of older drivers does not produce safety benefits
DEFF Research Database (Denmark)
Siren, Anu Kristiina; Meng, Annette
2012-01-01
Although screening policies for older drivers based on chronological age are widely used in many countries, previous research has shown that increasing age does not cause higher crash rates and that consequently, chronological age per se is at best only a weak predictor of safe driving performanc...... is an example of a political measure that intuitively makes sense, but fails to produce the desired benefits. On the contrary, on a system level, it decreases the overall safety and is connected to various direct and indirect costs........ Previous research on age-based mandatory screening of older drivers has not been able to demonstrate any safety benefits from screening measures.The present study is a population-based evaluation of the safety effects that the introduction of the cognitive test as an age-based screening tool has had...
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Evidence-based policy: implications for nursing and policy involvement.
Hewison, Alistair
2008-11-01
Evidence-based policy making is espoused as a central feature of government in the United Kingdom. However, an expectation that this will improve the quality of policy produced and provide a path to increased involvement of nurses in the policy process is misplaced. The purpose of this article is to demonstrate that the emphasis on evidence-based policy is problematic and cannot be regarded as a "new model" of policy making. Also, it could deflect attention from more practical approaches to policy involvement on the part of nurses. Policy development activities, acquisition of skills in policy analysis, and other forms of involvement are needed if nurses are to move along the continuum from policy literacy, through policy acumen, to policy competence. This involves taking a critical stance on the notion of evidence-based policy.
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Computer-Aided Evaluation of Screening Mammograms Based on Local Texture Models
Czech Academy of Sciences Publication Activity Database
Grim, Jiří; Somol, Petr; Haindl, Michal; Daneš, J.
2009-01-01
Roč. 18, č. 4 (2009), s. 765-773 ISSN 1057-7149 R&D Projects: GA ČR GA102/07/1594; GA ČR GA102/08/0593; GA MŠk 1M0572 Grant - others:GA MŠk(CZ) 2C06019 Institutional research plan: CEZ:AV0Z10750506 Keywords : Screening mammography * texture information * local statistical model * Gaussian mixture Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 2.848, year: 2009
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Gray, Ewan; Donten, Anna; Karssemeijer, Nico; van Gils, Carla; Evans, D Gareth; Astley, Sue; Payne, Katherine
2017-09-01
To identify the incremental costs and consequences of stratified national breast screening programs (stratified NBSPs) and drivers of relative cost-effectiveness. A decision-analytic model (discrete event simulation) was conceptualized to represent four stratified NBSPs (risk 1, risk 2, masking [supplemental screening for women with higher breast density], and masking and risk 1) compared with the current UK NBSP and no screening. The model assumed a lifetime horizon, the health service perspective to identify costs (£, 2015), and measured consequences in quality-adjusted life-years (QALYs). Multiple data sources were used: systematic reviews of effectiveness and utility, published studies reporting costs, and cohort studies embedded in existing NBSPs. Model parameter uncertainty was assessed using probabilistic sensitivity analysis and one-way sensitivity analysis. The base-case analysis, supported by probabilistic sensitivity analysis, suggested that the risk stratified NBSPs (risk 1 and risk-2) were relatively cost-effective when compared with the current UK NBSP, with incremental cost-effectiveness ratios of £16,689 per QALY and £23,924 per QALY, respectively. Stratified NBSP including masking approaches (supplemental screening for women with higher breast density) was not a cost-effective alternative, with incremental cost-effectiveness ratios of £212,947 per QALY (masking) and £75,254 per QALY (risk 1 and masking). When compared with no screening, all stratified NBSPs could be considered cost-effective. Key drivers of cost-effectiveness were discount rate, natural history model parameters, mammographic sensitivity, and biopsy rates for recalled cases. A key assumption was that the risk model used in the stratification process was perfectly calibrated to the population. This early model-based cost-effectiveness analysis provides indicative evidence for decision makers to understand the key drivers of costs and QALYs for exemplar stratified NBSP. Copyright
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Newborn screening by tandem mass spectrometry: ethical and social issues.
Avard, Denise; Vallance, Hilary; Greenberg, Cheryl; Potter, Beth
2007-01-01
Emerging technologies like Tandem Mass Spectrometry (TMS) enable multiple tests on a single blood sample and allow the expansion of Newborn Screening (NBS) to include various metabolic diseases. Introducing TMS for NBS raises important social and ethical questions: what are the criteria for adding disorders to screening panels? What evidence justifies expansion of screening? How can equity in NBS access and standards be ensured? How can policy standards be set, given the multiplicity of stakeholders? To address emerging issues, policy-makers, patient advocates, clinicians and researchers had a workshop during the 2005 Garrod Symposium. The participants received a summary of the discussion and understood the workshop's goal was to provide a basis for further discussion. This article contributes to this ongoing discussion. Several proposed recommendations assert the centrality of including social and ethical issues in the assessment of whether or not to introduce TMS. The article outlines five key recommendations for advancing the NBS agenda: national public health leadership; transparency; increased national consistency in NBS strategy, including minimum standards; collaboration between the federal and provincial/territorial governments and diverse stakeholders; and supporting research and/or programs based on effectiveness, which integrate ethical and social issues into assessment.
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Zeisser-Labouèbe, Magali; Delie, Florence; Gurny, Robert; Lange, Norbert
2009-02-01
In urology, fluorescence-based imaging methods have been proven to significantly improve the detection of small, barely visible tumors and reduce the recurrence rate. Under ethical and economical pressure, new effective screening systems have to be developed to exploit and assess novel strategies for fluorescence photodetection in other areas. For this purpose, the chorioallantoic membrane (CAM) of the developing chick embryo is an attractive alternative model to the mammalian models. Hypericin encapsulated into nanoparticles for the photodetection of ovarian metastases was evaluated in the CAM model with respect to vascular extravazation and tumor targeting and compared with free drug following intravenous administration. To validate the CAM model as a valuable screening system for photodetection of cancer, we drew a comparison with results obtained on a conventional rodent model. Rodent and CAM models led to the same conclusion regarding the benefits of nanoencapsulation to improve selective accumulation of drug in ovarian micrometastases.
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Directory of Open Access Journals (Sweden)
Lena M. Biehl
2017-04-01
Full Text Available Abstract To assess the scope of infection control measures for multidrug-resistant bacteria in high-risk settings, a survey among university hospitals was conducted. Fourteen professionals from 8 sites participated. Reported policies varied largely with respect to the types of wards conducting screening, sample types used for screening and implementation of contact precautions. This variability among sites highlights the need for an evidence-based consensus of current infection control policies.
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Patra, Somdatta; Upadhyay, Madhu; Chhabra, Pragti
2017-01-01
Cervical cancer is one of the most common malignancies among women in India. There is a high mortality as patients usually present at an advanced stage because of lack of awareness and nonexistent screening programs. This study was planned to find out awareness about cervical cancer among women and their willingness to utilize screening services in an urban resettlement colony of Delhi, India. A community-based, cross-sectional study was carried out in a resettlement colony of North-West Delhi. Semi-structured interview schedule was used to collect information regarding different aspects of cervical cancer. Analysis was done using SPSS package (SPSS version 16 (UCMS and GTBH, Delhi, India)). A total of 373 women were included in the study. Mean age of study participants was 39.14 years. Two-third of the study population were illiterate. Half of the study population was aware of cervical cancer, and only one-fourth of population were willing to participate in a screening test. Willingness was higher among educated, ever user of family planning method and having knowledge about at least one risk factor, signs or symptoms, or possibility of early diagnosis of cancer cervix. The country's national program advocates for opportunistic and targeted screening of women. An understanding of the factors that influences womens' willingness to participate in screening program is essential for the success of such programs. Hence, this study emphasizes the need for dissemination of knowledge about various aspects of cancer cervix which is critical for uptake of any screening program in a developing country.
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International Nuclear Information System (INIS)
Jaccard, Mark; Murphy, Rose; Rivers, Nic
2004-01-01
The transportation sector offers substantial potential for greenhouse gas (GHG) emission abatement, but widely divergent cost estimates complicate policy making; energy-economy policy modelers apply top-down and bottom-up cost definitions and different assumptions about future technologies and the preferences of firms and households. Our hybrid energy-economy policy model is technology-rich, like a bottom-up model, but has empirically estimated behavioral parameters for risk and technology preferences, like a top-down model. Unlike typical top-down models, however, it simulates technological change endogenously with functions that relate the financial costs of technologies to cumulative production and adjust technology preferences as market shares change. We apply it to the choice of personal vehicles to indicate, first, the effect on cost estimates of divergent cost definitions and, second, the possible response to policies that require a minimum market share for low emission vehicles
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Directory of Open Access Journals (Sweden)
Roberto Tapia-Conyer
2017-06-01
Full Text Available Mexico, like many low- and middle-income countries (LMICs, faces an epidemic of chronic non-communicable diseases (NCDs, specifically diabetes, hypertension, obesity, and lipid disorders. Many people with these NCDs may not be aware that they have a disease, pointing to the need for broader screening programs. The traditional prevention policy in Mexico was based on screening with a paper-based risk factor questionnaire. However, this was used to screen patients already seeking healthcare services at facilities, and screening goals were set as a function of the number of questionnaires applied, not number of individuals screened. Due to this, Fundación Carlos Slim developed Medición Integrada para la Detección Oportuna (MIDOTM, or Integrated Measurement for Early Detection, an NCD screening and proactive prevention policy. This document is a policy analysis based on early learnings from the initial implementation of MIDO in eight primary healthcare centers in two central Mexican states. MIDO was found to expand screening programs beyond clinic walls, systematize community screening strategies, emphasize the detection of pre-disease phases, incorporate lifestyle counseling, and propose screening goals based on population targets. In collaboration with the Mexican Ministry of Health, MIDO has successfully screened over 500 000 individuals—about 40% of whom would not have been screened under previous policies. Of these more than 500 000 screened individuals, 13.4% had pre-diabetes (fasting glucose between 100 and 125 mg/dL, and 5.8% had undiagnosed diabetes (defined as fasting glucose above 126 mg/dL or random glucose above 200 mg/dL. However, there is still room for improvement in linking positive results from screening with disease confirmation and with patient incorporation into disease management. The experience of implementing MIDO in Mexico suggests that primary and secondary prevention programs in other parts of the world should
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2018-01-01
The California Community Environmental Health Screening Tool (CalEnviroScreen) advances research and policy pertaining to environmental health vulnerability. However, CalEnviroScreen departs from its historical foundations and comparable screening tools by no longer considering racial status as an indicator of environmental health vulnerability and predictor of cumulative pollution burden. This study used conceptual frameworks and analytical techniques from environmental health and inequality literature to address the limitations of CalEnviroScreen, especially its inattention to race-based environmental health vulnerabilities. It developed an adjusted measure of cumulative pollution burden from the CalEnviroScreen 2.0 data that facilitates multivariate analyses of the effect of neighborhood racial composition on cumulative pollution burden, net of other indicators of population vulnerability, traffic density, industrial zoning, and local and regional clustering of pollution burden. Principal component analyses produced three new measures of population vulnerability, including Latina/o cumulative disadvantage that represents the spatial concentration of Latinas/os, economic disadvantage, limited English-speaking ability, and health vulnerability. Spatial error regression analyses demonstrated that concentrations of Latinas/os, followed by Latina/o cumulative disadvantage, are the strongest demographic determinants of adjusted cumulative pollution burden. Findings have implications for research and policy pertaining to cumulative impacts and race-based environmental health vulnerabilities within and beyond California. PMID:29659481
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Directory of Open Access Journals (Sweden)
Raoul S. Liévanos
2018-04-01
Full Text Available The California Community Environmental Health Screening Tool (CalEnviroScreen advances research and policy pertaining to environmental health vulnerability. However, CalEnviroScreen departs from its historical foundations and comparable screening tools by no longer considering racial status as an indicator of environmental health vulnerability and predictor of cumulative pollution burden. This study used conceptual frameworks and analytical techniques from environmental health and inequality literature to address the limitations of CalEnviroScreen, especially its inattention to race-based environmental health vulnerabilities. It developed an adjusted measure of cumulative pollution burden from the CalEnviroScreen 2.0 data that facilitates multivariate analyses of the effect of neighborhood racial composition on cumulative pollution burden, net of other indicators of population vulnerability, traffic density, industrial zoning, and local and regional clustering of pollution burden. Principal component analyses produced three new measures of population vulnerability, including Latina/o cumulative disadvantage that represents the spatial concentration of Latinas/os, economic disadvantage, limited English-speaking ability, and health vulnerability. Spatial error regression analyses demonstrated that concentrations of Latinas/os, followed by Latina/o cumulative disadvantage, are the strongest demographic determinants of adjusted cumulative pollution burden. Findings have implications for research and policy pertaining to cumulative impacts and race-based environmental health vulnerabilities within and beyond California.
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Liévanos, Raoul S
2018-04-16
The California Community Environmental Health Screening Tool (CalEnviroScreen) advances research and policy pertaining to environmental health vulnerability. However, CalEnviroScreen departs from its historical foundations and comparable screening tools by no longer considering racial status as an indicator of environmental health vulnerability and predictor of cumulative pollution burden. This study used conceptual frameworks and analytical techniques from environmental health and inequality literature to address the limitations of CalEnviroScreen, especially its inattention to race-based environmental health vulnerabilities. It developed an adjusted measure of cumulative pollution burden from the CalEnviroScreen 2.0 data that facilitates multivariate analyses of the effect of neighborhood racial composition on cumulative pollution burden, net of other indicators of population vulnerability, traffic density, industrial zoning, and local and regional clustering of pollution burden. Principal component analyses produced three new measures of population vulnerability, including Latina/o cumulative disadvantage that represents the spatial concentration of Latinas/os, economic disadvantage, limited English-speaking ability, and health vulnerability. Spatial error regression analyses demonstrated that concentrations of Latinas/os, followed by Latina/o cumulative disadvantage, are the strongest demographic determinants of adjusted cumulative pollution burden. Findings have implications for research and policy pertaining to cumulative impacts and race-based environmental health vulnerabilities within and beyond California.
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McDonald, Peter R; Roy, Anuradha; Chaguturu, Rathnam
2011-07-01
The University of Kansas High-Throughput Screening (KU HTS) core is a state-of-the-art drug-discovery facility with an entrepreneurial open-service policy, which provides centralized resources supporting public- and private-sector research initiatives. The KU HTS core was established in 2002 at the University of Kansas with support from an NIH grant and the state of Kansas. It collaborates with investigators from national and international academic, nonprofit and pharmaceutical organizations in executing HTS-ready assay development and screening of chemical libraries for target validation, probe selection, hit identification and lead optimization. This is part two of a contribution from the KU HTS laboratory.
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Directory of Open Access Journals (Sweden)
Virginia R Roth
Full Text Available The literature remains conflicted regarding the most effective way to screen for MRSA. This study was designed to assess costs associated with universal versus risk factor-based screening for the reduction of nosocomial MRSA transmission.The study was conducted at The Ottawa Hospital, a large multi-centre tertiary care facility with approximately 47,000 admissions annually. From January 2006-December 2007, patients underwent risk factor-based screening for MRSA on admission. From January 2008 to August 2009 universal MRSA screening was implemented. A comparison of costs incurred during risk factor-based screening and universal screening was conducted. The model incorporated probabilities relating to the likelihood of being tested and the results of polymerase chain reaction (PCR testing with associated effects in terms of MRSA bacteremia and true positive and negative test results. Inputted costs included laboratory testing, contact precautions and infection control, private room costs, housekeeping, and length of hospital stay. Deterministic sensitivity analyses were conducted.The risk factor-based MRSA screening program screened approximately 30% of admitted patients and cost the hospital over $780 000 annually. The universal screening program screened approximately 83% of admitted patients and cost over $1.94 million dollars, representing an excess cost of $1.16 million per year. The estimated additional cost per patient screened was $17.76.This analysis demonstrated that a universal MRSA screening program was costly from a hospital perspective and was previously known to not be clinically effective at reducing MRSA transmission. These results may be useful to inform future model-based economic analyses of MRSA interventions.
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Kim, Ki Joon; Sundar, S Shyam
2014-07-01
This study explores the psychological effects of screen size on smartphone adoption by proposing an extended Technology Acceptance Model (TAM) that integrates an empirical comparison between large and small screens with perceived control, affective quality, and the original TAM constructs. A structural equation modeling analysis was conducted on data collected from a between-subjects experiment (N=130) in which users performed a web-based task on a smartphone with either a large (5.3 inches) or a small (3.7 inches) screen. Results show that a large screen, compared to a small screen, is likely to lead to higher smartphone adoption by simultaneously promoting both the utilitarian and hedonic qualities of smartphones, which in turn positively influence perceived ease of use of-and attitude toward-the device respectively. Implications and directions for future research are discussed.
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Screening model for nanowire surface-charge sensors in liquid
DEFF Research Database (Denmark)
Sørensen, Martin Hedegård; Mortensen, Asger; Brandbyge, Mads
2007-01-01
The conductance change of nanowire field-effect transistors is considered a highly sensitive probe for surface charge. However, Debye screening of relevant physiological liquid environments challenge device performance due to competing screening from the ionic liquid and nanowire charge carriers....
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Vibration characteristics of an inclined flip-flow screen panel in banana flip-flow screens
Xiong, Xiaoyan; Niu, Linkai; Gu, Chengxiang; Wang, Yinhua
2017-12-01
A banana flip-flow screen is an effective solution for the screening of high-viscosity, high-water and fine materials. As one of the key components, the vibration characteristics of the inclined flip-flow screen panel largely affects the screen performance and the processing capacity. In this paper, a mathematical model for the vibration characteristic of the inclined flip-flow screen panel is proposed based on Catenary theory. The reasonability of Catenary theory in analyzing the vibration characteristic of flip-flow screen panels is verified by a published experiment. Moreover, the effects of the rotation speed of exciters, the incline angle, the slack length and the characteristics of the screen on the vertical deflection, the vertical velocity and the vertical acceleration of the screen panel are investigated parametrically. The results show that the rotation speed of exciters, the incline angle, the slack length and the characteristics of the screen have significant effects on the vibrations of an inclined flip-flow screen panel, and these parameters should be optimized.
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Hooker, Leesa; Small, Rhonda; Humphreys, Cathy; Hegarty, Kelsey; Taft, Angela
2015-03-28
In Victoria, Australia, Maternal and Child Health (MCH) services deliver primary health care to families with children 0-6 years, focusing on health promotion, parenting support and early intervention. Family violence (FV) has been identified as a major public health concern, with increased prevalence in the child-bearing years. Victorian Government policy recommends routine FV screening of all women attending MCH services. Using Normalization Process Theory (NPT), we aimed to understand the barriers and facilitators of implementing an enhanced screening model into MCH nurse clinical practice. NPT informed the process evaluation of a pragmatic, cluster randomised controlled trial in eight MCH nurse teams in metropolitan Melbourne, Victoria, Australia. Using mixed methods (surveys and interviews), we explored the views of MCH nurses, MCH nurse team leaders, FV liaison workers and FV managers on implementation of the model. Quantitative data were analysed by comparing proportionate group differences and change within trial arm over time between interim and impact nurse surveys. Qualitative data were inductively coded, thematically analysed and mapped to NPT constructs (coherence, cognitive participation, collective action and reflexive monitoring) to enhance our understanding of the outcome evaluation. MCH nurse participation rates for interim and impact surveys were 79% (127/160) and 71% (114/160), respectively. Twenty-three key stakeholder interviews were completed. FV screening work was meaningful and valued by participants; however, the implementation coincided with a significant (government directed) change in clinical practice which impacted on full engagement with the model (coherence and cognitive participation). The use of MCH nurse-designed FV screening/management tools in focussed women's health consultations and links with FV services enhanced the participants' work (collective action). Monitoring of FV work (reflexive monitoring) was limited. The use of
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Malard, J. J.; Baig, A. I.; Hassanzadeh, E.; Adamowski, J. F.; Tuy, H.; Melgar-Quiñonez, H.
2016-12-01
Model coupling is a crucial step to constructing many environmental models, as it allows for the integration of independently-built models representing different system sub-components to simulate the entire system. Model coupling has been of particular interest in combining socioeconomic System Dynamics (SD) models, whose visual interface facilitates their direct use by stakeholders, with more complex physically-based models of the environmental system. However, model coupling processes are often cumbersome and inflexible and require extensive programming knowledge, limiting their potential for continued use by stakeholders in policy design and analysis after the end of the project. Here, we present Tinamit, a flexible Python-based model-coupling software tool whose easy-to-use API and graphical user interface make the coupling of stakeholder-built SD models with physically-based models rapid, flexible and simple for users with limited to no coding knowledge. The flexibility of the system allows end users to modify the SD model as well as the linking variables between the two models themselves with no need for recoding. We use Tinamit to couple a stakeholder-built socioeconomic model of soil salinization in Pakistan with the physically-based soil salinity model SAHYSMOD. As climate extremes increase in the region, policies to slow or reverse soil salinity buildup are increasing in urgency and must take both socioeconomic and biophysical spheres into account. We use the Tinamit-coupled model to test the impact of integrated policy options (economic and regulatory incentives to farmers) on soil salinity in the region in the face of future climate change scenarios. Use of the Tinamit model allowed for rapid and flexible coupling of the two models, allowing the end user to continue making model structure and policy changes. In addition, the clear interface (in contrast to most model coupling code) makes the final coupled model easily accessible to stakeholders with
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Towards policy relevant environmental modeling: contextual validity and pragmatic models
Miles, Scott B.
2000-01-01
"What makes for a good model?" In various forms, this question is a question that, undoubtedly, many people, businesses, and institutions ponder with regards to their particular domain of modeling. One particular domain that is wrestling with this question is the multidisciplinary field of environmental modeling. Examples of environmental models range from models of contaminated ground water flow to the economic impact of natural disasters, such as earthquakes. One of the distinguishing claims of the field is the relevancy of environmental modeling to policy and environment-related decision-making in general. A pervasive view by both scientists and decision-makers is that a "good" model is one that is an accurate predictor. Thus, determining whether a model is "accurate" or "correct" is done by comparing model output to empirical observations. The expected outcome of this process, usually referred to as "validation" or "ground truthing," is a stamp on the model in question of "valid" or "not valid" that serves to indicate whether or not the model will be reliable before it is put into service in a decision-making context. In this paper, I begin by elaborating on the prevailing view of model validation and why this view must change. Drawing from concepts coming out of the studies of science and technology, I go on to propose a contextual view of validity that can overcome the problems associated with "ground truthing" models as an indicator of model goodness. The problem of how we talk about and determine model validity has much to do about how we perceive the utility of environmental models. In the remainder of the paper, I argue that we should adopt ideas of pragmatism in judging what makes for a good model and, in turn, developing good models. From such a perspective of model goodness, good environmental models should facilitate communication, convey—not bury or "eliminate"—uncertainties, and, thus, afford the active building of consensus decisions, instead
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Modeling sequential context effects in diagnostic interpretation of screening mammograms.
Alamudun, Folami; Paulus, Paige; Yoon, Hong-Jun; Tourassi, Georgia
2018-07-01
Prior research has shown that physicians' medical decisions can be influenced by sequential context, particularly in cases where successive stimuli exhibit similar characteristics when analyzing medical images. This type of systematic error is known to psychophysicists as sequential context effect as it indicates that judgments are influenced by features of and decisions about the preceding case in the sequence of examined cases, rather than being based solely on the peculiarities unique to the present case. We determine if radiologists experience some form of context bias, using screening mammography as the use case. To this end, we explore correlations between previous perceptual behavior and diagnostic decisions and current decisions. We hypothesize that a radiologist's visual search pattern and diagnostic decisions in previous cases are predictive of the radiologist's current diagnostic decisions. To test our hypothesis, we tasked 10 radiologists of varied experience to conduct blind reviews of 100 four-view screening mammograms. Eye-tracking data and diagnostic decisions were collected from each radiologist under conditions mimicking clinical practice. Perceptual behavior was quantified using the fractal dimension of gaze scanpath, which was computed using the Minkowski-Bouligand box-counting method. To test the effect of previous behavior and decisions, we conducted a multifactor fixed-effects ANOVA. Further, to examine the predictive value of previous perceptual behavior and decisions, we trained and evaluated a predictive model for radiologists' current diagnostic decisions. ANOVA tests showed that previous visual behavior, characterized by fractal analysis, previous diagnostic decisions, and image characteristics of previous cases are significant predictors of current diagnostic decisions. Additionally, predictive modeling of diagnostic decisions showed an overall improvement in prediction error when the model is trained on additional information about
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Directory of Open Access Journals (Sweden)
Margaret A. Brunton
2009-02-01
Full Text Available Changes in the organisation of health care have dominated policy initiatives over the past two decades in many countries. An increasing reliance on public health initiatives to prevent or detect disease early has resulted in an increase in programs that screen for cancer in the community. In turn, this accentuates the need to persuasively communicate the value of such initiatives to encourage continued participation. Merely placing screening programs into a community setting is not sufficient to ensure that adequate numbers will voluntarily participate regularly to achieve anticipated cost and mortality savings in the population. In this research the influence of managing communication in a public screening mammography program was investigated. The results revealed that significant opportunities were overlooked for reassurance and information during the physical mammography process. In turn, this highlights the influence of constraints imposed by the structure of the screening program and the resources allocated to the process. This research suggests that it is important to address multiple influences, including ethnic differences, when asking questions about the effectiveness of public health policy, particularly when considering the choices women make about ongoing participation in breast screening programs.
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Policy options for alcohol price regulation: the importance of modelling population heterogeneity.
Meier, Petra Sylvia; Purshouse, Robin; Brennan, Alan
2010-03-01
Context and aims Internationally, the repertoire of alcohol pricing policies has expanded to include targeted taxation, inflation-linked taxation, taxation based on alcohol-by-volume (ABV), minimum pricing policies (general or targeted), bans of below-cost selling and restricting price-based promotions. Policy makers clearly need to consider how options compare in reducing harms at the population level, but are also required to demonstrate proportionality of their actions, which necessitates a detailed understanding of policy effects on different population subgroups. This paper presents selected findings from a policy appraisal for the UK government and discusses the importance of accounting for population heterogeneity in such analyses. Method We have built a causal, deterministic, epidemiological model which takes account of differential preferences by population subgroups defined by age, gender and level of drinking (moderate, hazardous, harmful). We consider purchasing preferences in terms of the types and volumes of alcoholic beverages, prices paid and the balance between bars, clubs and restaurants as opposed to supermarkets and off-licenses. Results Age, sex and level of drinking fundamentally affect beverage preferences, drinking location, prices paid, price sensitivity and tendency to substitute for other beverage types. Pricing policies vary in their impact on different product types, price points and venues, thus having distinctly different effects on subgroups. Because population subgroups also have substantially different risk profiles for harms, policies are differentially effective in reducing health, crime, work-place absence and unemployment harms. Conclusion Policy appraisals must account for population heterogeneity and complexity if resulting interventions are to be well considered, proportionate, effective and cost-effective.
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Possible ecosystem impacts of applying maximum sustainable yield policy in food chain models.
Ghosh, Bapan; Kar, T K
2013-07-21
This paper describes the possible impacts of maximum sustainable yield (MSY) and maximum sustainable total yield (MSTY) policy in ecosystems. In general it is observed that exploitation at MSY (of single species) or MSTY (of multispecies) level may cause the extinction of several species. In particular, for traditional prey-predator system, fishing under combined harvesting effort at MSTY (if it exists) level may be a sustainable policy, but if MSTY does not exist then it is due to the extinction of the predator species only. In generalist prey-predator system, harvesting of any one of the species at MSY level is always a sustainable policy, but harvesting of both the species at MSTY level may or may not be a sustainable policy. In addition, we have also investigated the MSY and MSTY policy in a traditional tri-trophic and four trophic food chain models. Copyright © 2013 Elsevier Ltd. All rights reserved.
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‘It is a dilemma’: perspectives of nurse practitioners on health screening of newly arrived migrants
Directory of Open Access Journals (Sweden)
Faustine K. Nkulu Kalengayi
2015-07-01
Full Text Available Background: Screening newly arrived migrants from countries with high burden of communicable diseases of public health significance is part of the Swedish national strategy against the spread of these diseases. However, little is known about its implementation. Objective: This study aimed at exploring caregivers’ experiences in screening newly arrived migrants to generate knowledge that could inform policy and clinical practice. Design: Using an interpretive description framework, we conducted semistructured interviews between November and December 2011 in four Swedish counties, with 15 purposively selected nurses with experience in screening migrants. Data were analyzed using thematic analysis. Results: Participants described a range of challenges including discordant views between migrants and the nurses about medical screening, inconsistencies in rules and practices, and conflicting policies. Participants indicated that sociocultural differences resulted in divergent expectations with migrants viewing the participants as agents of migration authorities. They also expressed concern over being given a new assignment without training and being expected to share responsibilities with staff from other agencies without adequate coordination. Finally, they indicated that existing policies can be confusing and raise ethical issues. All these were compounded by language barriers, making their work environment extremely complex and stressful. Conclusions: These findings illuminate complex challenges that could limit access to, uptake, and delivery of health screening and undermine public health goals, and highlight the need for a multilevel approach. This entails avoiding the conflation of migration with health issues, harmonizing existing policies to make health care services more accessible and acceptable to migrants, and facilitating health professionals’ work in promoting public health, improving interagency collaboration and the skills of all
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Walkthrough screening evaluation field guide
International Nuclear Information System (INIS)
Eder, S.J.; Eli, M.W.; Salmon, M.W.
1993-11-01
The US Department of Energy (DOE) has a large inventory of existing facilities. Many of these facilities were not designed and constructed to current natural phenomena hazard (NPH) criteria. The NPH events include earthquakes, extreme winds and tornadoes, and floods. DOE Order 5480.28 establishes policy and requirements for NPH mitigation for DOE facilities. DOE is conducting a multiyear project to develop evaluation guidelines for assessing the condition and determining the need for upgrades at DOE facilities. One element of the NPH evaluation guidelines' development involves the existing systems and components at DOE facilities. This effort is described in detail in a cited reference. In the interim period prior to availability of the final guidelines, DOE facilities are encouraged to implement an NPH walk through screening evaluation process by which systems and components that need attention can be rapidly identified. Guidelines for conducting the walk through screening evaluations are contained herein. The result of the NPH walk through screening evaluation should be a prioritized list of systems and components that need further action. Simple and inexpensive fixes for items identified in the walk through as marginal or inadequate should be implemented without further study. By implementing an NPH walk through screening evaluation, DOE facilities may realize significant reduction in risk from NPH in the short term
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Kalliokoski, Tuomo; Ronkko, Toni; Poso, Antti
2008-06-01
Algorithms were developed for ligand-based virtual screening of molecular databases. FieldChopper (FC) is based on the discretization of the electrostatic and van der Waals field into three classes. A model is built from a set of superimposed active molecules. The similarity of the compounds in the database to the model is then calculated using matrices that define scores for comparing field values of different categories. The method was validated using 12 publicly available data sets by comparing the method to the electrostatic similarity comparison program EON. The results suggest that FC is competitive with more complex descriptors and could be used as a molecular sieve in virtual screening experiments when multiple active ligands are known.
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Calculation of radiative opacity of plasma mixtures using a relativistic screened hydrogenic model
International Nuclear Information System (INIS)
Mendoza, M.A.; Rubiano, J.G.; Gil, J.M.; Rodríguez, R.; Florido, R.; Espinosa, G.; Martel, P.; Mínguez, E.
2014-01-01
We present the code ATMED based on an average atom model and conceived for fast computing the population distribution and radiative properties of hot and dense single and multicomponent plasmas under LTE conditions. A relativistic screened hydrogenic model (RSHM), built on a new set of universal constants considering j-splitting, is used to calculate the required atomic data. The opacity model includes radiative bound–bound, bound–free, free–free, and scattering processes. Bound–bound line-shape function has contributions from natural, Doppler and electron-impact broadenings. An additional dielectronic broadening to account for fluctuations in the average level populations has been included, which improves substantially the Rosseland mean opacity results. To illustrate the main features of the code and its capabilities, calculations of several fundamental quantities of one-component plasmas and mixtures are presented, and a comparison with previously published data is performed. Results are satisfactorily compared with those predicted by more elaborate codes. - Highlights: • A new opacity code, ATMED, based on the average atom approximation is presented. • Atomic data are computed by means of a relativistic screened hydrogenic model. • An effective bound level degeneracy is included for accounting pressure ionization. • A new dielectronic line broadening is included to improve the mean opacities. • ATMED has the possibility to handle with single element and multicomponent plasmas
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ILP-2 modeling and virtual screening of an FDA-approved library:a possible anticancer therapy.
Khalili, Saeed; Mohammadpour, Hemn; Shokrollahi Barough, Mahideh; Kokhaei, Parviz
2016-06-23
The members of the inhibitors of apoptosis protein (IAP) family inhibit diverse components of the caspase signaling pathway, notably caspase 3, 7, and 9. ILP-2 (BIRC-8) is the most recently identified member of the IAPs, mainly interacting with caspase 9. This interaction would eventually lead to death resistance in the case of cancerous cells. Therefore, structural modeling of ILP-2 and finding applicable inhibitors of its interaction with caspase 9 are a compelling challenge. Three main protein modeling approaches along with various model refinement measures were harnessed to achieve a reliable 3D model, using state-of-the-art software. Thereafter, the selected model was employed to perform virtual screening of an FDA approved library. A model built by a combinatorial approach (homology and ab initio approaches) was chosen as the best model. Model refinement processes successfully bolstered the model quality. Virtual screening of the compound library introduced several high affinity inhibitor candidates that interact with functional residues of ILP2. Given the 3D structure of the ILP2 molecule, we found promising inhibitory molecules. In addition to high affinity towards the ILP2 molecule, these molecules interact with residues that play pivotal rules in ILP2-caspase interaction. These molecules would inhibit ILP2-caspase interaction and consequently would lead to reactivated cell apoptosis through the caspases pathway.
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Bailey, Stephanie L; Bono, Rose S; Nash, Denis; Kimmel, April D
2018-01-01
Spreadsheet software is increasingly used to implement systems science models informing health policy decisions, both in academia and in practice where technical capacity may be limited. However, spreadsheet models are prone to unintentional errors that may not always be identified using standard error-checking techniques. Our objective was to illustrate, through a methodologic case study analysis, the impact of unintentional errors on model projections by implementing parallel model versions. We leveraged a real-world need to revise an existing spreadsheet model designed to inform HIV policy. We developed three parallel versions of a previously validated spreadsheet-based model; versions differed by the spreadsheet cell-referencing approach (named single cells; column/row references; named matrices). For each version, we implemented three model revisions (re-entry into care; guideline-concordant treatment initiation; immediate treatment initiation). After standard error-checking, we identified unintentional errors by comparing model output across the three versions. Concordant model output across all versions was considered error-free. We calculated the impact of unintentional errors as the percentage difference in model projections between model versions with and without unintentional errors, using +/-5% difference to define a material error. We identified 58 original and 4,331 propagated unintentional errors across all model versions and revisions. Over 40% (24/58) of original unintentional errors occurred in the column/row reference model version; most (23/24) were due to incorrect cell references. Overall, >20% of model spreadsheet cells had material unintentional errors. When examining error impact along the HIV care continuum, the percentage difference between versions with and without unintentional errors ranged from +3% to +16% (named single cells), +26% to +76% (column/row reference), and 0% (named matrices). Standard error-checking techniques may not
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Whitt-Woosley, Adrienne; Sprang, Ginny; Royse, David G
2018-07-01
Children in the child welfare system comprise a group characterized by exposure to trauma via experiences of maltreatment, under circumstances presenting multiple risk factors for traumatic stress. High rates of posttraumatic stress have been observed in this population. However, there is currently no standard for the universal screening of children in child welfare for trauma exposure and traumatic stress. This study examined the trauma experiences of a sample of maltreated children and whether their child welfare workers were effective screeners of traumatic stress symptoms. Descriptive and correlational analyses were conducted regarding a sample of children (N = 131) with trauma screenings completed by their child welfare workers and clinical measures of traumatic stress symptoms. Four hierarchical regression models were also examined to determine whether workers' screening information regarding child age, trauma exposure history and symptoms of traumatic stress were predictive of outcomes on clinical measures. The analyses revealed complex trauma exposure histories and high rates of traumatic stress symptoms among this generally younger sample of maltreated children. Additionally, the models supported workers' efficacy in screening for symptoms of total posttraumatic stress and specific trauma symptoms of intrusion and avoidance. Workers were less effective in screening for the symptoms of arousal. These findings support the importance of identifying the trauma recovery needs of maltreated children and the utility of child protection workers in assisting with the trauma screening process. Implications are provided for related practice, policy and training efforts in child welfare. Published by Elsevier Ltd.
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Maintenance overtime policies in reliability theory models with random working cycles
Nakagawa, Toshio
2015-01-01
This book introduces a new concept of replacement in maintenance and reliability theory. Replacement overtime, where replacement occurs at the first completion of a working cycle over a planned time, is a new research topic in maintenance theory and also serves to provide a fresh optimization technique in reliability engineering. In comparing replacement overtime with standard and random replacement techniques theoretically and numerically, 'Maintenance Overtime Policies in Reliability Theory' highlights the key benefits to be gained by adopting this new approach and shows how they can be applied to inspection policies, parallel systems and cumulative damage models. Utilizing the latest research in replacement overtime by internationally recognized experts, readers are introduced to new topics and methods, and learn how to practically apply this knowledge to actual reliability models. This book will serve as an essential guide to a new subject of study for graduate students and researchers and also provides a...
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Turner, Katy; Adams, Elisabeth; Grant, Arabella; Macleod, John; Bell, Gill; Clarke, Jan; Horner, Paddy
2011-01-04
To compare the cost, cost effectiveness, and sex equity of different intervention strategies within the English National Chlamydia Screening Programme. To develop a tool for calculating cost effectiveness of chlamydia control programmes at a local, national, or international level. An economic and mathematical modelling study with cost effectiveness analysis. Costs were restricted to those of screening and partner notification from the perspective of the NHS and excluded patient costs, the costs of reinfection, and costs of complications arising from initial infection. England. Population Individuals eligible for the National Chlamydia Screening Programme. Cost effectiveness of National Chlamydia Screening Programme in 2008-9 (as cost per individual tested, cost per positive diagnosis, total cost of screening, number screened, number infected, sex ratio of those tested and treated). Comparison of baseline programme with two different interventions-(i) increased coverage of primary screening in men and (ii) increased efficacy of partner notification. In 2008-9 screening was estimated to cost about £46.3m in total and £506 per infection treated. Provision for partner notification within the screening programme cost between £9 and £27 per index case, excluding treatment and testing. The model results suggest that increasing male screening coverage from 8% (baseline value) to 24% (to match female coverage) would cost an extra £22.9m and increase the cost per infection treated to £528. In contrast, increasing partner notification efficacy from 0.4 (baseline value) to 0.8 partners per index case would cost an extra £3.3m and would reduce the cost per infection diagnosed to £449. Increasing screening coverage to 24% in men would cost over six times as much as increasing partner notification to 0.8 but only treat twice as many additional infections. In the English National Chlamydia Screening Programme increasing the effectiveness of partner notification is likely
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Directory of Open Access Journals (Sweden)
Guillermo Cabrera
2013-01-01
Full Text Available We solve a novel inventory-location model with a stochastic capacity constraint based on a periodic inventory control (ILM-PR policy. The ILM-PR policy implies several changes with regard to other previous models proposed in the literature, which consider continuous review as their inventory policy. One of these changes is the inclusion of the undershoot concept, which has not been considered in previous ILM models in the literature. Based on our model, we are able to design a distribution network for a two-level supply chain, addressing both warehouse location and customer assignment decisions, whilst taking into consideration several aspects of inventory planning, in particular, evaluating the impact of the inventory control review period on the network configuration and system costs. Because the model is a very hard-to solve combinatorial nonlinear optimisation problem, we implemented two heuristics to solve it, namely, Tabu Search and Particle Swarm Optimisation. These approaches were tested over small instances in which they were able to find the optimal solution in just a few seconds. Because the model is a new one, a set of medium-size instances is provided that can be useful as a benchmark in future research. The heuristics showed a good convergence rate when applied to those instances. The results confirm that decision making over the inventory control policy has effects on the distribution network design.
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Color screening effect in the quark potential model
International Nuclear Information System (INIS)
Zhang Zongye; Yu Youwen; Shen Pengnian; Shen Xiaoyan; Dong Yubin
1993-01-01
By using the color confinement potential which includes the color screening effect, we studied the baryon spectra and the nucleon-nucleon interaction. The results show that the color screening effect not only improves the baryon spectrum calculation, but also can solve the long-tail problem of the color Van der Waals force. A part of the medium attraction of the nuclear force can be obtained from the color Van der Waals force. (orig.)
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K. ten Haaf (Kevin); J. Jeon (Jihyoun); M.C. Tammemagi (Martin); S.S. Han (Summer); C.Y. Kong (Chung Yin); S.K. Plevritis (Sylvia); E. Feuer (Eric); H.J. de Koning (Harry); E.W. Steyerberg (Ewout W.); R. Meza (Rafael)
2017-01-01
textabstractBackground: Selection of candidates for lung cancer screening based on individual risk has been proposed as an alternative to criteria based on age and cumulative smoking exposure (pack-years). Nine previously established risk models were assessed for their ability to identify those most
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Garg, Arvin; Dworkin, Paul H
2011-06-01
Within the medical home, understanding the family and community context in which children live is critical to optimally promoting children's health and development. How to best identify psychosocial issues likely to have an impact on children's development is uncertain. Professional guidelines encourage pediatricians to incorporate family psychosocial screening within the context of primary care, yet few providers routinely screen for these issues. The authors propose applying the core principles of surveillance and screening, as applied to children's development and behavior, to also address family psychosocial issues during health supervision services. Integrating psychosocial surveillance and screening into the medical home requires changes in professional training, provider practice, and public policy. The potential of family psychosocial surveillance and screening to promote children's optimal development justifies such changes.
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Performance of third-trimester combined screening model for prediction of adverse perinatal outcome.
Miranda, J; Triunfo, S; Rodriguez-Lopez, M; Sairanen, M; Kouru, H; Parra-Saavedra, M; Crovetto, F; Figueras, F; Crispi, F; Gratacós, E
2017-09-01
To explore the potential value of third-trimester combined screening for the prediction of adverse perinatal outcome (APO) in the general population and among small-for-gestational-age (SGA) fetuses. This was a nested case-control study within a prospective cohort of 1590 singleton gestations undergoing third-trimester evaluation (32 + 0 to 36 + 6 weeks' gestation). Maternal baseline characteristics, mean arterial blood pressure, fetoplacental ultrasound and circulating biochemical markers (placental growth factor (PlGF), lipocalin-2, unconjugated estriol and inhibin A) were assessed in all women who subsequently had an APO (n = 148) and in a control group without perinatal complications (n = 902). APO was defined as the occurrence of stillbirth, umbilical artery cord blood pH < 7.15, 5-min Apgar score < 7 or emergency operative delivery for fetal distress. Logistic regression models were developed for the prediction of APO in the general population and among SGA cases (defined as customized birth weight < 10 th centile). The prevalence of APO was 9.3% in the general population and 27.4% among SGA cases. In the general population, a combined screening model including a-priori risk (maternal characteristics), estimated fetal weight (EFW) centile, umbilical artery pulsatility index (UA-PI), estriol and PlGF achieved a detection rate for APO of 26% (area under receiver-operating characteristics curve (AUC), 0.59 (95% CI, 0.54-0.65)), at a 10% false-positive rate (FPR). Among SGA cases, a model including a-priori risk, EFW centile, UA-PI, cerebroplacental ratio, estriol and PlGF predicted 62% of APO (AUC, 0.86 (95% CI, 0.80-0.92)) at a FPR of 10%. The use of fetal ultrasound and maternal biochemical markers at 32-36 weeks provides a poor prediction of APO in the general population. Although it remains limited, the performance of the screening model is improved when applied to fetuses with suboptimal fetal growth. Copyright © 2016 ISUOG. Published by John Wiley & Sons
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Directory of Open Access Journals (Sweden)
Bretteville-Jensen Anne Line
2014-04-01
Full Text Available BACKGROUND - Despite decades of intensive anti-tobacco initiatives, millions of people are still smoking. The health authorities are seeking new tools and extended knowledge. Screening programs may, in addition to the potential health benefits from early detection of smoking related diseases, also increase smoking cessation among participants. This study examines the effect of screening participation by comparing the smokers’ cessation hazard in screening years to nonscreening years. METHODS - All smokers (n=10,471 participated in a three-wave cardiovascular screening and were followed up over a maximum of 14 years. The panel was merged with administrative registers. We used a flexible discrete-time duration model to investigate the effect of the screening program while simultaneously accounting for the possible influence of personal characteristics, addiction indicators, economic factors, health status and health changes. Specifically, we examined and compared long-term smokers (LT; smoked ≥25 years with short-term (ST; smoked ≤ 5 years and medium-term (MT; smoked 10-20 years smokers. RESULTS - We found that 29% of LT smokers quitted smoking during the follow-up whereas 32% of MT and 48% of ST smokers reported the same. The screening participation years stood out as especially important for all groups. The impact of the first screening was particularly high, and for the first two screenings, the effect was higher for long-term smokers than for the smokers with shorter smoking careers. Receiving an abnormal test result was not associated with a significant increase in cessation hazard for any group of smokers. CONCLUSIONS - The substantial effect of being invited to and participating in a screening appears robust, and may prove useful when discussing future policies for smoking cessation. This paper suggests that further initiatives for consultations with health personnel, in this case through a screening program, could increase the
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Rossouw, Riaan; Saayman, Melville
2011-01-01
Historically, tourism policy analysis in South Africa has posed challenges to accurate measurement. The primary reason for this is that tourism is not designated as an 'industry' in standard economic accounts. This paper therefore demonstrates the relevance and need for applied general equilibrium (AGE) models to be completed and extended through an integration with tourism satellite accounts (TSAs) as a tool for policy makers (especially tourism policy makers) in South Africa. The paper sets...
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Pharmacophore modeling, virtual screening and molecular docking of ATPase inhibitors of HSP70.
Sangeetha, K; Sasikala, R P; Meena, K S
2017-10-01
Heat shock protein 70 is an effective anticancer target as it influences many signaling pathways. Hence the study investigated the important pharmacophore feature required for ATPase inhibitors of HSP70 by generating a ligand based pharmacophore model followed by virtual based screening and subsequent validation by molecular docking in Discovery studio V4.0. The most extrapolative pharmacophore model (hypotheses 8) consisted of four hydrogen bond acceptors. Further validation by external test set prediction identified 200 hits from Mini Maybridge, Drug Diverse, SCPDB compounds and Phytochemicals. Consequently, the screened compounds were refined by rule of five, ADMET and molecular docking to retain the best competitive hits. Finally Phytochemical compounds Muricatetrocin B, Diacetylphiladelphicalactone C, Eleutheroside B and 5-(3-{[1-(benzylsulfonyl)piperidin-4-yl]amino}phenyl)- 4-bromo-3-(carboxymethoxy)thiophene-2-carboxylic acid were obtained as leads to inhibit the ATPase activity of HSP70 in our findings and thus can be proposed for further in vitro and in vivo evaluation. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Kallåk Anundsen , André; Sigurd Holmsen Krogh, Tord; Nymoen, Ragnar; Vislie, Jon
2011-01-01
This paper presents the business cycle model that Trygve Haavelmo developed as part of his research program in macroeconomic and monetary theory. Driven by a mismatch between the marginal return to capital and the rate of return required by capital owners, this model generates endogenous cycles. The theory leads to a distinct analysis of the scope and limitations of monetary policy. A main message of the model is that care should be taken when conducting 'autonomous' monetary policy and that ...
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Energy production from biogas in the Italian countryside: Policies and organizational models
International Nuclear Information System (INIS)
Carrosio, Giovanni
2013-01-01
In recent years, Italy has witnessed a proliferation of agricultural biogas plants. This article argues that institutional factors have played an important role in their diffusion. It describes the state and evolution of agricultural biogas in Italy, and then investigates the extent to which institutional pressures have been influential in shaping organizational models of biogas production. It finds that the dominance of one particular organizational model is the result of an isomorphic process in which a monopolistic market, legal structures, and subsidies play a role. The prevalence of this organizational model, however, does not lead to the effective use of biogas production, and furthermore it results in low environmental efficiency. For a more sustainable development of bioenergy, Italian policy-makers should reform the existing institutional framework by reorganizing subsidies, liberalizing the management of gas grids, and involving farmers in local projects. - Highlights: • Institutional factors played an important role for the diffusion of biogas plants in Italy. • The dominance of one organizational model is the result of an isomorphic process. • The prevalence of one organizational model results in low environmental efficiency. • Italian policy makers should reform the existing institutional framework
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Screening and Recording of Patients' Alcohol‑use Habit by ...
African Journals Online (AJOL)
Background: Alcohol is widely consumed in Ireland; more so in major urban centers. Alcohol‑related problems account for a significant number of Accident and Emergency (A and E) department presentations in Ireland. As a result, the national alcohol policy calls on doctors to be proactive in screening for and addressing ...
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Luminescence studies on phosphor screens
International Nuclear Information System (INIS)
Panayiotakis, G.; Nomikos, C.; Bakas, A.; Proimos, B.
1994-01-01
We report our results on x-ray phosphor screens prepared of some new materials focusing attention on their efficiency under fluoroscopy conditions, on optimization conditions and on comparisons among the various materials. All data are presented in absolute values. A theoretical model is presented, that takes into account the granular structure of the screens, permitting the explanation and prediction of the luminescence properties of the screens. (authors)
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Hop, Cornelis E C A; Cole, Mark J; Davidson, Ralph E; Duignan, David B; Federico, James; Janiszewski, John S; Jenkins, Kelly; Krueger, Suzanne; Lebowitz, Rebecca; Liston, Theodore E; Mitchell, Walter; Snyder, Mark; Steyn, Stefan J; Soglia, John R; Taylor, Christine; Troutman, Matt D; Umland, John; West, Michael; Whalen, Kevin M; Zelesky, Veronica; Zhao, Sabrina X
2008-11-01
Evaluation and optimization of drug metabolism and pharmacokinetic data plays an important role in drug discovery and development and several reliable in vitro ADME models are available. Recently higher throughput in vitro ADME screening facilities have been established in order to be able to evaluate an appreciable fraction of synthesized compounds. The ADME screening process can be dissected in five distinct steps: (1) plate management of compounds in need of in vitro ADME data, (2) optimization of the MS/MS method for the compounds, (3) in vitro ADME experiments and sample clean up, (4) collection and reduction of the raw LC-MS/MS data and (5) archival of the processed ADME data. All steps will be described in detail and the value of the data on drug discovery projects will be discussed as well. Finally, in vitro ADME screening can generate large quantities of data obtained under identical conditions to allow building of reliable in silico models.
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Optimization of maintenance policy using the proportional hazard model
Energy Technology Data Exchange (ETDEWEB)
Samrout, M. [Information Sciences and Technologies Institute, University of Technology of Troyes, 10000 Troyes (France)], E-mail: mohamad.el_samrout@utt.fr; Chatelet, E. [Information Sciences and Technologies Institute, University of Technology of Troyes, 10000 Troyes (France)], E-mail: chatelt@utt.fr; Kouta, R. [M3M Laboratory, University of Technology of Belfort Montbeliard (France); Chebbo, N. [Industrial Systems Laboratory, IUT, Lebanese University (Lebanon)
2009-01-15
The evolution of system reliability depends on its structure as well as on the evolution of its components reliability. The latter is a function of component age during a system's operating life. Component aging is strongly affected by maintenance activities performed on the system. In this work, we consider two categories of maintenance activities: corrective maintenance (CM) and preventive maintenance (PM). Maintenance actions are characterized by their ability to reduce this age. PM consists of actions applied on components while they are operating, whereas CM actions occur when the component breaks down. In this paper, we expound a new method to integrate the effect of CM while planning for the PM policy. The proportional hazard function was used as a modeling tool for that purpose. Interesting results were obtained when comparison between policies that take into consideration the CM effect and those that do not is established.
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Katikireddi, Srinivasa V; Bond, Lyndal; Hilton, Shona
2014-06-01
Novel policy interventions may lack evaluation-based evidence. Considerations to introduce minimum unit pricing (MUP) of alcohol in the UK were informed by econometric modelling (the 'Sheffield model'). We aim to investigate policy stakeholders' views of the utility of modelling studies for public health policy. In-depth qualitative interviews with 36 individuals involved in MUP policy debates (purposively sampled to include civil servants, politicians, academics, advocates and industry-related actors) were conducted and thematically analysed. Interviewees felt familiar with modelling studies and often displayed detailed understandings of the Sheffield model. Despite this, many were uneasy about the extent to which the Sheffield model could be relied on for informing policymaking and preferred traditional evaluations. A tension was identified between this preference for post hoc evaluations and a desire for evidence derived from local data, with modelling seen to offer high external validity. MUP critics expressed concern that the Sheffield model did not adequately capture the 'real life' world of the alcohol market, which was conceptualized as a complex and, to some extent, inherently unpredictable system. Communication of modelling results was considered intrinsically difficult but presenting an appropriate picture of the uncertainties inherent in modelling was viewed as desirable. There was general enthusiasm for increased use of econometric modelling to inform future policymaking but an appreciation that such evidence should only form one input into the process. Modelling studies are valued by policymakers as they provide contextually relevant evidence for novel policies, but tensions exist with views of traditional evaluation-based evidence. © The Author 2013. Published by Oxford University Press on behalf of the European Public Health Association.
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O'Gorman, Neil; Wright, David; Syngelaki, Argyro; Akolekar, Ranjit; Wright, Alan; Poon, Leona C; Nicolaides, Kypros H
2016-01-01
Preeclampsia affects approximately 3% of all pregnancies and is a major cause of maternal and perinatal morbidity and death. In the last decade, extensive research has been devoted to early screening for preeclampsia with the aim of reducing the prevalence of the disease through pharmacologic intervention in the high-risk group starting from the first trimester of pregnancy. The purpose of this study was to develop a model for preeclampsia based on maternal demographic characteristics and medical history (maternal factors) and biomarkers. The data for this study were derived from prospective screening for adverse obstetric outcomes in women who attended for their routine first hospital visit at 11-13 weeks gestation in 2 maternity hospitals in England. We screened 35,948 singleton pregnancies that included 1058 pregnancies (2.9%) that experienced preeclampsia. Bayes theorem was used to combine the a priori risk from maternal factors with various combinations of uterine artery pulsatility index, mean arterial pressure, serum pregnancy-associated plasma protein-A, and placental growth factor multiple of the median values. Five-fold cross validation was used to assess the performance of screening for preeclampsia that delivered at preeclampsia) and ≥37 weeks gestation (term-preeclampsia) by models that combined maternal factors with individual biomarkers and their combination with screening by maternal factors alone. In pregnancies that experienced preeclampsia, the values of uterine artery pulsatility index and mean arterial pressure were increased, and the values of serum pregnancy-associated plasma protein-A and placental growth factor were decreased. For all biomarkers, the deviation from normal was greater for early than late preeclampsia; therefore, the performance of screening was related inversely to the gestational age at which delivery became necessary for maternal and/or fetal indications. Combined screening by maternal factors, uterine artery pulsatility
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P.L. Tedder; R.N. La Mont; J.C. Kincaid
1987-01-01
TRIM (Timber Resource Inventory Model) is a yield table projection system developed for timber supply projections and policy analysis. TRIM simulates timber growth, inventories, management and area changes, and removals over the projection period. Programs in the TRIM system, card-by-card descriptions of required inputs, table formats, and sample results are presented...
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Risk Profiling May Improve Lung Cancer Screening
A new modeling study suggests that individualized, risk-based selection of ever-smokers for lung cancer screening may prevent more lung cancer deaths and improve the effectiveness and efficiency of screening compared with current screening recommendations
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Screening diagnostic program breast cancer
International Nuclear Information System (INIS)
Portnoj, L.M.; Zhakova, I.I.; Budnikova, N.V.; Rukhlyadko, E.D.
1995-01-01
The authors propose their screening program for detection of breast cancer. It includes the entire complex of present-day screening diagnostic methods, starting from an original system for the formation of groups at risk of breast cancer and completed by the direct diagnostic model of detection of the condition, oriented at a differentiated approach to the use of mammographic techniques. The proposed organizational and methodologic screening measures are both economic and diagnostically effective, thus meeting the principal requirements to screening programs. Screening of 8541 risk-groups patients helped detect 867 nodular formations, 244 of which were cancer and 623 benign formations. 8 refs., 3 figs.,
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Novel gene function revealed by mouse mutagenesis screens for models of age-related disease.
Potter, Paul K; Bowl, Michael R; Jeyarajan, Prashanthini; Wisby, Laura; Blease, Andrew; Goldsworthy, Michelle E; Simon, Michelle M; Greenaway, Simon; Michel, Vincent; Barnard, Alun; Aguilar, Carlos; Agnew, Thomas; Banks, Gareth; Blake, Andrew; Chessum, Lauren; Dorning, Joanne; Falcone, Sara; Goosey, Laurence; Harris, Shelley; Haynes, Andy; Heise, Ines; Hillier, Rosie; Hough, Tertius; Hoslin, Angela; Hutchison, Marie; King, Ruairidh; Kumar, Saumya; Lad, Heena V; Law, Gemma; MacLaren, Robert E; Morse, Susan; Nicol, Thomas; Parker, Andrew; Pickford, Karen; Sethi, Siddharth; Starbuck, Becky; Stelma, Femke; Cheeseman, Michael; Cross, Sally H; Foster, Russell G; Jackson, Ian J; Peirson, Stuart N; Thakker, Rajesh V; Vincent, Tonia; Scudamore, Cheryl; Wells, Sara; El-Amraoui, Aziz; Petit, Christine; Acevedo-Arozena, Abraham; Nolan, Patrick M; Cox, Roger; Mallon, Anne-Marie; Brown, Steve D M
2016-08-18
Determining the genetic bases of age-related disease remains a major challenge requiring a spectrum of approaches from human and clinical genetics to the utilization of model organism studies. Here we report a large-scale genetic screen in mice employing a phenotype-driven discovery platform to identify mutations resulting in age-related disease, both late-onset and progressive. We have utilized N-ethyl-N-nitrosourea mutagenesis to generate pedigrees of mutagenized mice that were subject to recurrent screens for mutant phenotypes as the mice aged. In total, we identify 105 distinct mutant lines from 157 pedigrees analysed, out of which 27 are late-onset phenotypes across a range of physiological systems. Using whole-genome sequencing we uncover the underlying genes for 44 of these mutant phenotypes, including 12 late-onset phenotypes. These genes reveal a number of novel pathways involved with age-related disease. We illustrate our findings by the recovery and characterization of a novel mouse model of age-related hearing loss.
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Determining potential locations for biomass valorization using a macro screening approach
Energy Technology Data Exchange (ETDEWEB)
Van Dael, M.; Van Passel, S.; Schreurs, E. [Research Group of Environmental Economics, Centre for Environmental Sciences, Hasselt University, Agoralaan Gebouw D, 3590 Diepenbeek (Belgium); Pelkmans, L.; Guisson, R. [VITO, Boeretang 200, 2400 Mol (Belgium); Swinnen, G. [Research Group of Marketing, Hasselt University, Agoralaan Gebouw D, 3590 Diepenbeek (Belgium)
2012-10-15
European policy states that by 2020 at least 20% of final energy consumption should come from renewable energy sources. Biomass as a renewable energy source cannot be disregarded in order to attain this target. In this study a macro screening approach is developed to determine potential locations for biomass valorization in a specified region. The approach consists of five steps: (1) criteria determination, (2) data gathering, (3) weight assignment, (4) final score, (5) spatial representation. The resulting outcome provides a first well balanced scan of the possibilities for energy production using regional biomass. This way policy makers and investors can be supported and motivated to study the possibilities of building energy production plants at specific locations in more detail, which can be described as a 'micro-screening'. In our case study the approach is applied to determine the potentially interesting locations to establish a biomass project. The region has been limited to the forty-four communities in the province of Limburg (Belgium). The macro screening approach has shown to be very effective since the amount of interesting locations has been reduced drastically.
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Prostitution and Human Trafficking : A model-based exploration and policy analysis
Kovari, A.; Pruyt, E.
2012-01-01
The meeting of the oldest profession with modern slavery is the topic of this paper. After a brief introduction to prostitution and prostitution-related human trafficking, this paper focuses on the Dutch policy debate. A System Dynamics simulation model related to the Dutch situation developed to
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Washington, W. M.
2010-12-01
The development of climate and earth system models has been regarded primarily as the making of scientific tools to study the complex nature of the Earth’s climate. These models have a long history starting with very simple physical models based on fundamental physics in the 1960s and over time they have become much more complex with atmospheric, ocean, sea ice, land/vegetation, biogeochemical, glacial and ecological components. The policy use aspects of these models did not start in the 1960s and 1970s as decision making tools but were used to answer fundamental scientific questions such as what happens when the atmospheric carbon dioxide concentration increases or is doubled. They gave insights into the various interactions and were extensively compared with observations. It was realized that models of the earlier time periods could only give first order answers to many of the fundamental policy questions. As societal concerns about climate change rose, the policy questions of anthropogenic climate change became better defined; they were mostly concerned with the climate impacts of increasing greenhouse gases, aerosols, and land cover change. In the late 1980s, the United Nations set up the Intergovernmental Panel on Climate Change to perform assessments of the published literature. Thus, the development of climate and Earth system models became intimately linked to the need to not only improve our scientific understanding but also answering fundamental policy questions. In order to meet this challenge, the models became more complex and realistic so that they could address these policy oriented science questions such as rising sea level. The presentation will discuss the past and future development of global climate and earth system models for science and policy purposes. Also to be discussed is their interactions with economic integrated assessment models, regional and specialized models such as river transport or ecological components. As an example of one
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Fang, Xingang; Bagui, Sikha; Bagui, Subhash
2017-08-01
The readily available high throughput screening (HTS) data from the PubChem database provides an opportunity for mining of small molecules in a variety of biological systems using machine learning techniques. From the thousands of available molecular descriptors developed to encode useful chemical information representing the characteristics of molecules, descriptor selection is an essential step in building an optimal quantitative structural-activity relationship (QSAR) model. For the development of a systematic descriptor selection strategy, we need the understanding of the relationship between: (i) the descriptor selection; (ii) the choice of the machine learning model; and (iii) the characteristics of the target bio-molecule. In this work, we employed the Signature descriptor to generate a dataset on the Human kallikrein 5 (hK 5) inhibition confirmatory assay data and compared multiple classification models including logistic regression, support vector machine, random forest and k-nearest neighbor. Under optimal conditions, the logistic regression model provided extremely high overall accuracy (98%) and precision (90%), with good sensitivity (65%) in the cross validation test. In testing the primary HTS screening data with more than 200K molecular structures, the logistic regression model exhibited the capability of eliminating more than 99.9% of the inactive structures. As part of our exploration of the descriptor-model-target relationship, the excellent predictive performance of the combination of the Signature descriptor and the logistic regression model on the assay data of the Human kallikrein 5 (hK 5) target suggested a feasible descriptor/model selection strategy on similar targets. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Directory of Open Access Journals (Sweden)
Luz Myriam Reynales-Shigematsu
Full Text Available OBJECTIVE: To examine how policies adopted in Mexico in response to the Framework Convention on Tobacco Control affected smoking prevalence and smoking-attributable deaths. METHODS: The SimSmoke simulation model of tobacco control policy is applied to Mexico. This discrete time, first-order Markov model uses data on population size, smoking rates and tobacco control policy for Mexico. It assesses, individually and jointly, the effects of seven types of policies: cigarette taxes, smoke-free air laws, mass media campaigns, advertising bans, warning labels, cessation treatment, and youth tobacco access policies. RESULTS: The Mexico SimSmoke model estimates that smoking rates have been reduced by about 30% as a result of policies implemented since 2002, and that the number of smoking-attributable deaths will have been reduced by about 826 000 by 2053. Increases in cigarette prices are responsible for over 60% of the reductions, but health warnings, smoke-free air laws, marketing restrictions and cessation treatments also play important roles. CONCLUSIONS: Mexico has shown steady progress towards reducing smoking prevalence in a short period of time, as have other Latin American countries, such as Brazil, Panama and Uruguay. Tobacco control policies play an important role in continued efforts to reduce tobacco use and associated deaths in Mexico.