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  1. Individual laboratory-measured discount rates predict field behavior.

    Science.gov (United States)

    Chabris, Christopher F; Laibson, David; Morris, Carrie L; Schuldt, Jonathon P; Taubinsky, Dmitry

    2008-12-01

    We estimate discount rates of 555 subjects using a laboratory task and find that these individual discount rates predict inter-individual variation in field behaviors (e.g., exercise, BMI, smoking). The correlation between the discount rate and each field behavior is small: none exceeds 0.28 and many are near 0. However, the discount rate has at least as much predictive power as any variable in our dataset (e.g., sex, age, education). The correlation between the discount rate and field behavior rises when field behaviors are aggregated: these correlations range from 0.09-0.38. We present a model that explains why specific intertemporal choice behaviors are only weakly correlated with discount rates, even though discount rates robustly predict aggregates of intertemporal decisions.

  2. Stress hormones predict hyperbolic time-discount rates six months later in adults.

    Science.gov (United States)

    Takahashi, Taiki; Shinada, Mizuho; Inukai, Keigo; Tanida, Shigehito; Takahashi, Chisato; Mifune, Nobuhiro; Takagishi, Haruto; Horita, Yutaka; Hashimoto, Hirofumi; Yokota, Kunihiro; Kameda, Tatsuya; Yamagishi, Toshio

    2010-01-01

    Stress hormones have been associated with temporal discounting. Although time-discount rate is shown to be stable over a long term, no study to date examines whether individual differences in stress hormones could predict individuals' time-discount rates in the relatively distant future (e.g., six month later), which is of interest in neuroeconomics of stress-addiction association. We assessed 87 participants' salivary stress hormone (cortisol, cortisone, and alpha-amylase) levels and hyperbolic discounting of delayed rewards consisting of three magnitudes, at the time-interval of six months. For salivary steroid assays, we employed a liquid chromatography/ mass spectroscopy (LC/MS) method. The correlations between the stress hormone levels and time-discount rates were examined. We observed that salivary alpha-amylase (sAA) levels were negatively associated with time-discount rates in never-smokers. Notably, salivary levels of stress steroids (i.e., cortisol and cortisone) negatively and positively related to time-discount rates in men and women, respectively, in never-smokers. Ever-smokers' discount rates were not predicted from these stress hormone levels. Individual differences in stress hormone levels predict impulsivity in temporal discounting in the future. There are sex differences in the effect of stress steroids on temporal discounting; while there was no sex defference in the relationship between sAA and temporal discounting.

  3. On multiple discount rates

    OpenAIRE

    Chambers, Christopher P.; Echenique, Federico

    2016-01-01

    We propose a theory of intertemporal choice that is robust to specific assumptions on the discount rate. One class of models requires that one utility stream be chosen over another if and only if its discounted value is higher for all discount factors in a set. Another model focuses on an average discount factor. Yet another model is pessimistic, and evaluates a flow by the lowest available discounted value.

  4. Subjective discount rates in the general population and their predictive power for energy saving behavior

    International Nuclear Information System (INIS)

    Bruderer Enzler, Heidi; Diekmann, Andreas; Meyer, Reto

    2014-01-01

    Why do people sometimes refrain from saving energy even if it would pay off in monetary terms? Subjective discount rates present one possible explanation for this lack of foresight, but little is known about their level and reliability in the general population. With regard to behavior, persons with lower discount rates are expected to accept additional costs upfront more readily than those with higher discount rates. Based on a representative nation-wide study, the Swiss Environmental Survey 2007, and a follow-up survey, our analyses reveal that on average subjective discount rates are well above market interest rates and moderately stable over a time interval of four years. Income and education are negatively correlated with discount rates. Contrary to expectations, we did not find convincing support for an impact of discount rates on energy saving behavior. - Highlights: • Results of a large panel study in Switzerland. • Mean subjective discount rates in population are well above market interest rates. • Subjective discount rates are moderately stable over four years. • Theory suggests impact of subjective discount rates on energy saving behavior. • However, subjective discount rates do not contribute to explanation of energy saving behavior

  5. Decomposing the social discount rate

    OpenAIRE

    Scarborough, Helen

    2010-01-01

    Recent modelling of the costs and benefits of climate change has renewed debate surrounding assumptions regarding the social discount rate in analysing the impacts of environmental change. Previous literature segments the social discount rate into being influenced by two key factors; the rate of pure time preference and the elasticity of marginal utility of future consumption. These components of the social discount rate reinforce the linkages between the choice of social discount rate and in...

  6. Aggregate Social Discount Rate Derived from Individual Discount Rates

    OpenAIRE

    Kenneth F. Reinschmidt

    2002-01-01

    In the economic evaluation of large public-sector projects, an aggregate social discount rate may be used in present worth comparison of alternatives. This paper uses the assumptions that individual discount rates are constant over time and approximately Normally distributed across the affected population, with mean \\mu and variance \\sigma 2 , to derive an aggregate discount function that is exponential in form but with time-dependent aggregate discount rate \\rho (t) = \\mu - \\sigma 2 t/2, whe...

  7. Smoking, Discount Rates, and Returns to Education

    Science.gov (United States)

    Fersterer, Josef; Winter-Ebmer, Rudolf

    2003-01-01

    Individual time preference determines schooling enrolment. Moreover, smoking behavior in early ages has been shown to be highly related to time preference rates. Insofar as discount rates are uncorrelated to ability, predicting school enrolment by discount rates can get rid of the ability bias in an earnings regression. Accordingly, we use smoking…

  8. Brain Activity in Valuation Regions while Thinking about the Future Predicts Individual Discount Rates

    Science.gov (United States)

    Cooper, Nicole; Kim, B. Kyu; Zauberman, Gal

    2013-01-01

    People vary widely in how much they discount delayed rewards, yet little is known about the sources of these differences. Here we demonstrate that neural activity in ventromedial prefrontal cortex (VMPFC) and ventral striatum (VS) when human subjects are asked to merely think about the future—specifically, to judge the subjective length of future time intervals—predicts delay discounting. High discounters showed lower activity for longer time delays, while low discounters showed the opposite pattern. Our results demonstrate that the correlation between VMPFC and VS activity and discounting occurs even in the absence of choices about future rewards, and does not depend on a person explicitly evaluating future outcomes or judging their self-relevance. This suggests a link between discounting and basic processes involved in thinking about the future, such as temporal perception. Our results also suggest that reducing impatience requires not suppression of VMPFC and VS activity altogether, but rather modulation of how these regions respond to the present versus the future. PMID:23926268

  9. Estimating Discount Rates

    Directory of Open Access Journals (Sweden)

    Laurence Booth

    2015-04-01

    Full Text Available Discount rates are essential to applied finance, especially in setting prices for regulated utilities and valuing the liabilities of insurance companies and defined benefit pension plans. This paper reviews the basic building blocks for estimating discount rates. It also examines market risk premiums, as well as what constitutes a benchmark fair or required rate of return, in the aftermath of the financial crisis and the U.S. Federal Reserve’s bond-buying program. Some of the results are disconcerting. In Canada, utilities and pension regulators responded to the crash in different ways. Utilities regulators haven’t passed on the full impact of low interest rates, so that consumers face higher prices than they should whereas pension regulators have done the opposite, and forced some contributors to pay more. In both cases this is opposite to the desired effect of monetary policy which is to stimulate aggregate demand. A comprehensive survey of global finance professionals carried out last year provides some clues as to where adjustments are needed. In the U.S., the average equity market required return was estimated at 8.0 per cent; Canada’s is 7.40 per cent, due to the lower market risk premium and the lower risk-free rate. This paper adds a wealth of historic and survey data to conclude that the ideal base long-term interest rate used in risk premium models should be 4.0 per cent, producing an overall expected market return of 9-10.0 per cent. The same data indicate that allowed returns to utilities are currently too high, while the use of current bond yields in solvency valuations of pension plans and life insurers is unhelpful unless there is a realistic expectation that the plans will soon be terminated.

  10. Intergenerational equity and the social discount rate

    OpenAIRE

    Scarborough, Helen

    2011-01-01

    Recent modelling of the costs and benefits of climate change has renewed debate regarding assumptions for the social discount rate in analysing the impacts of environmental change. Previous literature suggests two key factors influence estimates of the social discount rate: the rate of pure time preference and the elasticity of marginal utility of future consumption. These components of the social discount rate reinforce the linkages between the choice of social discount rate and intergenerat...

  11. 18 CFR 704.39 - Discount rate.

    Science.gov (United States)

    2010-04-01

    ... 18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false Discount rate. 704.39... STANDARDS AND PROCEDURES Standards for Plan Formulation and Evaluation § 704.39 Discount rate. (a) The interest rate to be used in plan formulation and evaluation for discounting future benefits and computing...

  12. Optimal Discount Rates for Government Projects

    OpenAIRE

    Park, Sangkyun

    2012-01-01

    Project selection based on the net present value can be optimal only if the discount rate is optimal. The optimal discount rate for a government project can be a risk-free rate, a comparable market rate (market interest rate corresponding to the risk of cash flows to the government), or an adjusted market rate, depending on circumstances. This paper clarifies the conditions for each case. Provided that the optimal discount rate is the comparable market rate, it varies across intervention meth...

  13. The Individual Health Discount Rate in Patients with Ulcerative Colitis

    Science.gov (United States)

    Waljee, Akbar K.; Morris, Arden M.; Waljee, Jennifer F.; Higgins, Peter D.R.

    2015-01-01

    Background In cost-effectiveness analysis, discount rates are used in calculating the value of future costs and benefits. However, standard discount rates may not accurately describe the decision-making of patients with Ulcerative Colitis (UC). These patients often choose the long-term risks of immunosuppressive therapy over the short-term risks of colectomy, demonstrating very high discount rates for future health. In this study, we aimed to measure the discount rate in UC patients and identify variables associated with the discount rate. Methods We surveyed patients with UC and patients who were post-colectomy for UC to measure their valuations of UC and colectomy health states. We used Standard Gamble(SG) and Time-Trade-Off(TTO) methods to assess current and future health state valuations, and calculated the discount rate. Results Participants included 150 subjects with UC and 150 subjects who were post-colectomy for UC. Discount rates varied widely (20.6%–100%) with an overall median rate of 55.0%, which was significantly higher than the standard rate of 5%. Older age and male gender and predicted high discount rates (aversion to immediate risk in favor of distant future risk). For each additional decade of age, patients’ expected discount rate increased by 0.77%. Female gender was the only predictor of very low discount rates. Female patients’ discount rates averaged 8.1% less than age-matched males. Conclusions The accepted discount rate of 5% grossly underestimates UC patients’ preference for long-term over short-term risk. This might explain UC patients’ frequent choice of the long-term risks of immunosuppressive medical therapy over the short-term risks of colectomy. PMID:21560195

  14. Life cycle costing with a discount rate

    Science.gov (United States)

    Posner, E. C.

    1978-01-01

    This article studies life cycle costing for a capability needed for the indefinite future, and specifically investigates the dependence of optimal policies on the discount rate chosen. The two costs considered are reprocurement cost and maintenance and operations (M and O) cost. The procurement price is assumed known, and the M and O costs are assumed to be a known function, in fact, a non-decreasing function, of the time since last reprocurement. The problem is to choose the optimum reprocurement time so as to minimize the quotient of the total cost over a reprocurement period divided by the period. Or one could assume a discount rate and try to minimize the total discounted costs into the indefinite future. It is shown that the optimum policy in the presence of a small discount rate hardly depends on the discount rate at all, and leads to essentially the same policy as in the case in which discounting is not considered.

  15. Uncertain discount rates in climate policy analysis

    International Nuclear Information System (INIS)

    Newell, R.G.; Pizer, W.A.

    2004-01-01

    Consequences in the distant future - such as those from climate change--have little value today when discounted using conventional rates. This result contradicts our 'gut feeling' about such problems and often leads to ad hoc application of lower rates for valuations over longer horizons - a step facilitated by confusion and disagreement over the correct rate even over short horizons. We review the theory and intuition behind the choice of discount rates now and, importantly, the impact of likely variation in rates in the future. Correlated changes in future rates imply that the distant future should be discounted at much lower rates than suggested by the current rate, thereby raising the value of future consequences - regardless of opinions concerning the current rate. Using historic data to quantity the likely changes and correlation in changes in future rates, we find that future valuations rise by a factor of many thousands at horizons of 300 years or more, almost doubling the expected present value of climate mitigation benefits relative to constant 4% discounting. Ironically, uncertainty about future rates reduces the ratio of valuations based on alternate choices of the current rate

  16. Do Declining Discount Rates lead to Time Inconsistent Economic Advice?

    DEFF Research Database (Denmark)

    Hansen, Anders Chr.

    2006-01-01

    This paper addresses the risk of time inconsistency in economic appraisals related to the use of hyperbolic discounting (declining discount rates) instead of exponential discounting (constant discount rate). Many economists are uneasy about the prospects of potential time inconsistency. The paper...

  17. Discounting

    International Nuclear Information System (INIS)

    Jones, P.M.S.

    1987-01-01

    Discounting is a procedure used to facilitate comparison of investment options where either or both the investment and income are spread out in time. It is based on the observation that under most circumstances a sum of money in the hand is worth more to the holder than the same sum in real terms in the future, because the holder can use the money in the intervening time. As discounting is used widely in economic assessment it is valid to use it for assessing electricity generation by nuclear power or fuel cycle costs. The way in which discounting works is explained, including factors such as risk and non-monetary aspects. The rate of the discount is a matter of government policy. In the United Kingdom it is currently (1986) 5 percent per annum for projects such as hospitals and road building. There is no good reason for this to be different for energy projects. (U.K.)

  18. Skiba points for small discount rates

    NARCIS (Netherlands)

    Wagener, F.O.O.

    2006-01-01

    The present article uses perturbation techniques to approximate the value function of an economic minimization problem for small values of the discount rate. This can be used to obtain the approximate location of the Skiba states in the problem; these are states for which there are two distinct

  19. A 5-trial adjusting delay discounting task: Accurate discount rates in less than 60 seconds

    Science.gov (United States)

    Koffarnus, Mikhail N.; Bickel, Warren K.

    2014-01-01

    Individuals who discount delayed rewards at a high rate are more likely to engage in substance abuse, overeating, or problem gambling. Findings such as these suggest the value of methods to obtain an accurate and fast measurement of discount rate that can be easily deployed in variety of settings. In the present study, we developed and evaluated the 5-trial adjusting delay task, a novel method of obtaining discount rate in less than one minute. We hypothesized that discount rates from the 5-trial adjusting delay task would be similar and correlated with discount rates from a lengthier task we have used previously, and that four known effects relating to delay discounting would be replicable with this novel task. To test these hypotheses, the 5-trial adjusting delay task was administered to 111 college students six times to obtain discount rates for six different commodities, along with a lengthier adjusting amount discounting task. We found that discount rates were similar and correlated between the 5-trial adjusting delay task and the adjusting amount task. Each of the four known effects relating to delay discounting was replicated with the 5-trial adjusting delay task to varying degrees. First, discount rates were inversely correlated with amount. Second, discount rates between past and future outcomes were correlated. Third, discount rates were greater for consumable rewards than with money, although we did not control for amount in this comparison. Fourth, discount rates were lower when zero amounts opposing the chosen time point were explicitly described. Results indicate that the 5-trial adjusting delay task is a viable, rapid method to assess discount rate. PMID:24708144

  20. A 5-trial adjusting delay discounting task: accurate discount rates in less than one minute.

    Science.gov (United States)

    Koffarnus, Mikhail N; Bickel, Warren K

    2014-06-01

    Individuals who discount delayed rewards at a high rate are more likely to engage in substance abuse, overeating, or problem gambling. Such findings suggest the value of methods to obtain an accurate and fast measurement of discount rate that can be easily deployed in variety of settings. In the present study, we developed and evaluated the 5-trial adjusting delay task, a novel method of obtaining a discount rate in less than 1 min. We hypothesized that discount rates from the 5-trial adjusting delay task would be similar and would correlate with discount rates from a lengthier task we have used previously, and that 4 known effects relating to delay discounting would be replicable with this novel task. To test these hypotheses, the 5-trial adjusting delay task was administered to 111 college students 6 times to obtain discount rates for 6 different commodities, along with a lengthier adjusting amount discounting task. We found that discount rates were similar and correlated between the 5-trial adjusting delay task and the adjusting amount task. Each of the 4 known effects relating to delay discounting was replicated with the 5-trial adjusting delay task to varying degrees. First, discount rates were inversely correlated with amount. Second, discount rates between past and future outcomes were correlated. Third, discount rates were greater for consumable rewards than with money, although we did not control for amount in this comparison. Fourth, discount rates were lower when $0 amounts opposing the chosen time point were explicitly described. Results indicate that the 5-trial adjusting delay task is a viable, rapid method to assess discount rate. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  1. Estimating implied rates of discount in healthcare decision-making.

    Science.gov (United States)

    West, R R; McNabb, R; Thompson, A G H; Sheldon, T A; Grimley Evans, J

    2003-01-01

    themselves. Both public and health professional samples tended to choose lower discount rates in health-related comparisons than in finance-related comparisons. It was also suggested that implied rates of discount, derived from responses to hypothetical questions, can be influenced by detail of question framing. The study suggested that both the lay public and healthcare professionals consider that the discount rate appropriate for public decisions is lower than that for private decisions. This finding suggests that lay people as well as healthcare professionals, used to making decisions on behalf of others, recognise that society is not simply an aggregate of individuals. It also implies a general appreciation that society is more stable and has a more predictable future than does the individual. There is fairly general support for this view in the theoretical literature and limited support in the few previous direct comparisons. Further research is indicated, possibly involving more in-depth interviewing and drawing inference on real, rather than hypothetical choices.

  2. Intergenerational transfers and the social discount rate

    International Nuclear Information System (INIS)

    Howarth, R.B.; Norgaard, R.B.

    1992-08-01

    This paper investigates the relationship between intergenerational asset transfers and the choice of the discount rate for use in cost-benefit analysis in a model of a competitive overlapping generations economy constrained by a socially managed exhaustible resource. Provided that there are no distortions in capital markets and that all agents hold perfect foresight, cost-benefit techniques will result in a Pareto efficient resource allocation if the discount rate is set equal to the market rate of interest. But since the path of the interest rate depends on the level of intergenerational transfers, cost-benefit techniques do not ensure a socially desirable distribution of welfare between generations; a social optimum will result only if intergenerational transfers are properly chosen and enforced. Decentralized private altruism may result in intergenerational transfers that both present and future individuals would agree are too small if members of the present generation attach positive weight to the general welfare of future generations, not simply their personal descendants. In a world where intergenerational transfers are non-optimal, second-best policy-making may imply a constrained optimum that is inefficient. Together, these findings suggest that cost-benefit analysis is at best a partial criterion to policy formulation that should be used only in conjunction with ethical principles that define the proper distribution of welfare between present and future generations

  3. Can we use human judgments to determine the discount rate?

    Science.gov (United States)

    Baron, J

    2000-12-01

    It has been suggested that the long-term discount rate for environmental goods should decrease at longer delays. One justification for this suggestion is that human judgments support it. This article presents an experiment showing that judgments concerning discount rates are internally inconsistent. These results point to potential problems with the use of judgments referenda for determining discount rates in cost-benefit analyses.

  4. Individual health discount rate in patients with ulcerative colitis.

    Science.gov (United States)

    Waljee, Akbar K; Morris, Arden M; Waljee, Jennifer F; Higgins, Peter D R

    2011-06-01

    In cost-effectiveness analysis, discount rates are used in calculating the value of future costs and benefits. However, standard discount rates may not accurately describe the decision-making of patients with ulcerative colitis (UC). These patients often choose the long-term risks of immunosuppressive therapy over the short-term risks of colectomy, demonstrating very high discount rates for future health. In this study we aimed to measure the discount rate in UC patients and identify variables associated with the discount rate. We surveyed patients with UC and patients who were postcolectomy for UC to measure their valuations of UC and colectomy health states. We used Standard Gamble (SG) and Time-Trade-Off (TTO) methods to assess current and future health state valuations and calculated the discount rate. Participants included 150 subjects with UC and 150 subjects who were postcolectomy for UC. Adjusted discount rates varied widely (0%-100%), with an overall median rate of 55.0% (interquartile range [IQR] 20.6-100), which was significantly higher than the standard rate of 5%. Within the normal range of discount rates, patients' expected discount rate increased by 0.80% for each additional year of age, and female patients had discount rates that averaged ≈ 8% less than their age-matched counterparts and approached statistical significance. The accepted discount rate of 5% grossly underestimates UC patients' preference for long-term over short-term risk. This might explain UC patients' frequent choice of the long-term risks of immunosuppressive medical therapy over the short-term risks of colectomy. Copyright © 2010 Crohn's & Colitis Foundation of America, Inc.

  5. Estimation of social discount rate for Lithuania

    Directory of Open Access Journals (Sweden)

    Vilma Kazlauskiene

    2016-09-01

    Full Text Available Purpose of the article: The paper seeks to analyse the problematics of estimation of the social discount rate (SDR. The SDR is the critical parameter of cost-benefit analysis, which allows calculating the present value of cost and the benefit of public sector investment projects. Incorrect choice of the SDR can lead to the realisation of ineffective public project or conversely, cost-effective project will be rejected. The relevance of this problem analysis is determined by discussions and different viewpoints of scientists on the choice of the most appropriate approach to determine the SDR and absence of methodically based the SDR on the national level of Lithuania. Methodology/methods: The research is performed by the scientific and methodical literature analysis, systematization, time series and regression analysis. Scientific aim: The aim of the article is to calculate the SDR based on the statistical data of Lithuania. Findings: The analysis of methods of SDR determination, as well as the researches performed by foreign researchers, allows stating that the social rate of time preference (SRTP approach is the most appropriate. The SDR, calculated by the SRTP approach, reflects the main purpose of public investment projects, i.e. to enhance social benefit for society, the best. The analyses of SDR determination practice of the foreign countries shows that the SDR level should not be universal for all states. Each country should calculate the SDR based on its own data and apply it for the assessment of public projects. Conclusions: The calculated SDR for Lithuania using the SRTP approach varies between 3.5% and 4.3%. Although it is lower than 5% that is offered by European Commission, this rate is based on the statistical data of Lithuania and should be used for the assessment of the national public projects. Applicatio

  6. Associations between Antisocial Personality Disorder and Sex on Discounting Rates.

    Science.gov (United States)

    Andrade, Leonardo F; Riven, Levi; Petry, Nancy M

    2014-12-01

    Numerous studies show that individuals with substance use and gambling problems discount delayed and probabilistic outcomes at different rates than controls. Few studies, however, investigated the association of discounting with antisocial personality disorders (ASPD), and none evaluated whether sex impacts these relationships. Because females with ASPD exhibit different patterns of antisocial behavior than their male counterparts, they may also differ in their decision-making tendencies. This study examined the effects of ASPD and sex on discounting in pathological gamblers. Results revealed effects of ASPD, and an interaction between ASPD and sex, on probability discounting rates. None of these variables, however, were related to delay discounting. Females with ASPD highly preferred probabilistic outcomes, suggesting that female gamblers with ASPD are particularly impulsive when it comes to probabilistic rewards. Greater understanding of sex differences in ASPD might help guide the selection of more effective sex-specific prevention and treatment programs.

  7. Review of assessment methods discount rate in investment analysis

    Directory of Open Access Journals (Sweden)

    Yamaletdinova Guzel Hamidullovna

    2011-08-01

    Full Text Available The article examines the current methods of calculating discount rate in investment analysis and business valuation, as well as analyzes the key problems using various techniques in terms of the Russian economy.

  8. Discount Rate and Timber Rotation: the Case of Eucalyptus Saligna

    OpenAIRE

    Camilo Restrepo; Mauricio Alviar

    2010-01-01

    Eucalyptus is one of the most important economical and environmental species in Colombia. The main goal of this article is to study the relationship between the discount rate and the year of Eucalyptus Saligna optimal harvest, through the Fisher and Hotelling’s method. The methodology consists of calculating the maximum Net Present Value and performing a sensitivity analysis between the year of harvest and the discount rate. The area of study is located in the eastern region of the state of A...

  9. Discounting the distant future—Data on Australian discount rates estimated by a stochastic interest rate model

    Directory of Open Access Journals (Sweden)

    Chi Truong

    2017-04-01

    Full Text Available Data on certainty equivalent discount factors and discount rates for stochastic interest rates in Australia are provided in this paper. The data has been used for the analysis of investments into climate adaptation projects in ׳It׳s not now or never: Implications of investment timing and risk aversion on climate adaptation to extreme events׳ (Truong and Trück, 2016 [3] and can be used for other cost-benefit analysis studies in Australia. The data is of particular interest for the discounting of projects that create monetary costs and benefits in the distant future.

  10. Discounting the distant future-Data on Australian discount rates estimated by a stochastic interest rate model.

    Science.gov (United States)

    Truong, Chi; Trück, Stefan

    2017-04-01

    Data on certainty equivalent discount factors and discount rates for stochastic interest rates in Australia are provided in this paper. The data has been used for the analysis of investments into climate adaptation projects in ׳It׳s not now or never: Implications of investment timing and risk aversion on climate adaptation to extreme events ׳ (Truong and Trück, 2016) [3] and can be used for other cost-benefit analysis studies in Australia. The data is of particular interest for the discounting of projects that create monetary costs and benefits in the distant future.

  11. An Adjusted Discount Rate Model for Fuel Cycle Cost Estimation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S. K.; Kang, G. B.; Ko, W. I. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    Owing to the diverse nuclear fuel cycle options available, including direct disposal, it is necessary to select the optimum nuclear fuel cycles in consideration of the political and social environments as well as the technical stability and economic efficiency of each country. Economic efficiency is therefore one of the significant evaluation standards. In particular, because nuclear fuel cycle cost may vary in each country, and the estimated cost usually prevails over the real cost, when evaluating the economic efficiency, any existing uncertainty needs to be removed when possible to produce reliable cost information. Many countries still do not have reprocessing facilities, and no globally commercialized HLW (High-level waste) repository is available. A nuclear fuel cycle cost estimation model is therefore inevitably subject to uncertainty. This paper analyzes the uncertainty arising out of a nuclear fuel cycle cost evaluation from the viewpoint of a cost estimation model. Compared to the same discount rate model, the nuclear fuel cycle cost of a different discount rate model is reduced because the generation quantity as denominator in Equation has been discounted. Namely, if the discount rate reduces in the back-end process of the nuclear fuel cycle, the nuclear fuel cycle cost is also reduced. Further, it was found that the cost of the same discount rate model is overestimated compared with the different discount rate model as a whole.

  12. An Adjusted Discount Rate Model for Fuel Cycle Cost Estimation

    International Nuclear Information System (INIS)

    Kim, S. K.; Kang, G. B.; Ko, W. I.

    2013-01-01

    Owing to the diverse nuclear fuel cycle options available, including direct disposal, it is necessary to select the optimum nuclear fuel cycles in consideration of the political and social environments as well as the technical stability and economic efficiency of each country. Economic efficiency is therefore one of the significant evaluation standards. In particular, because nuclear fuel cycle cost may vary in each country, and the estimated cost usually prevails over the real cost, when evaluating the economic efficiency, any existing uncertainty needs to be removed when possible to produce reliable cost information. Many countries still do not have reprocessing facilities, and no globally commercialized HLW (High-level waste) repository is available. A nuclear fuel cycle cost estimation model is therefore inevitably subject to uncertainty. This paper analyzes the uncertainty arising out of a nuclear fuel cycle cost evaluation from the viewpoint of a cost estimation model. Compared to the same discount rate model, the nuclear fuel cycle cost of a different discount rate model is reduced because the generation quantity as denominator in Equation has been discounted. Namely, if the discount rate reduces in the back-end process of the nuclear fuel cycle, the nuclear fuel cycle cost is also reduced. Further, it was found that the cost of the same discount rate model is overestimated compared with the different discount rate model as a whole

  13. Selection of a discount rate for use in NRC regulatory analyses and application of discount rates to future averted health effects

    International Nuclear Information System (INIS)

    Paananen, O.H.; Hendrickson, P.L.

    1993-01-01

    The principal objective of this report is to provide background information and recommendations on the use of discount rates in the regulatory analysis process. The report focuses on two issues selecting the appropriate discount rate or rates to use when conducting a regulatory analysis, and applying the selected discount rate to future health-related benefits estimated to result from alternative regulatory actions

  14. Incentivizing Decentralized Sanitation: The Role of Discount Rates.

    Science.gov (United States)

    Wood, Alison; Blackhurst, Michael; Garland, Jay L; Lawler, Desmond F

    2016-06-21

    In adoption decisions for decentralized sanitation technologies, two decision makers are involved: the public utility and the individual homeowner. Standard life cycle cost is calculated from the perspective of the utility, which uses a market-based discount rate in these calculations. However, both decision-makers must be considered, including their differing perceptions of the time trade-offs inherent in a stream of costs and benefits. This study uses the discount rate as a proxy for these perceptions and decision-maker preferences. The results in two case studies emphasize the dependence on location of such analyses. Falmouth, Massachusetts, appears to be a good candidate for incentivizing decentralized sanitation while the Allegheny County Sanitary Authority service area in Pennsylvania appears to have no need for similar incentives. This method can be applied to any two-party decision in which the parties are expected to have different discount rates.

  15. Temporal discounting and heart rate reactivity to stress.

    Science.gov (United States)

    Diller, James W; Patros, Connor H G; Prentice, Paula R

    2011-07-01

    Temporal discounting is the reduction of the value of a reinforcer as a function of increasing delay to its presentation. Impulsive individuals discount delayed consequences more rapidly than self-controlled individuals, and impulsivity has been related to substance abuse, gambling, and other problem behaviors. A growing body of literature has identified biological correlates of impulsivity, though little research to date has examined relations between delay discounting and markers of poor health (e.g., cardiovascular reactivity to stress). We evaluated the relation between one aspect of impulsivity, measured using a computerized temporal discounting task, and heart rate reactivity, measured as a change in heart rate from rest during a serial subtraction task. A linear regression showed that individuals who were more reactive to stress responded more impulsively (i.e., discounted delayed reinforcers more rapidly). When results were stratified by gender, the effect was observed for females, but not for males. This finding supports previous research on gender differences in cardiovascular reactivity and suggests that this type of reactivity may be an important correlate of impulsive behavior. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. Description, prescription and the choice of discount rates

    International Nuclear Information System (INIS)

    Baum, Seth D.

    2009-01-01

    The choice of discount rates is a key issue in the analysis of long-term societal issues, in particular environmental issues such as climate change. Approaches to choosing discount rates are generally placed into two categories: the descriptive approach and the prescriptive approach. The descriptive approach is often justified on grounds that it uses a description of how society discounts instead of having analysts impose their own discounting views on society. This paper analyzes the common forms of the descriptive and prescriptive approaches and finds that, in contrast with customary thinking, both forms are equally descriptive and prescriptive. The prescriptions concern who has standing (i.e. who is included) in society, how the views of these individuals are measured, and how the measurements are aggregated. Such prescriptions are necessary to choose from among the many possible descriptions of how society discounts. The descriptions are the measurements made given a choice of measurement technique. Thus, the labels 'descriptive approach' and 'prescriptive approach' are deeply misleading, as analysts cannot avoid imposing their own views on society. (author)

  17. Discount rates for social cost benefit analysis of nuclear energy

    International Nuclear Information System (INIS)

    Owen, P.A.

    1978-01-01

    The question that this paper addresses is how decisions affecting many citizens should be made when there are uncertain outcomes in the distant future. By distant is meant beyond the lifetimes of individuals alive now. Thus the proposed methodology would apply to many decisions in nuclear energy from the investment in new energy sources such as fusion, to the long-term storage of wastes. Decisions of this type have usually been analyzed using cost benefit analysis. In this case, future outcomes are discounted at the so-called social discount rate. By comparison, the proposed methodology uses information on individual citizen's preferences and willingness to pay to make a future generation better off. The connection between the proposed approach and more traditional discounting techniques is examined using the government decision about storing helium for the future as an example

  18. Combining Environmental and Spatial Discount Rates for Valuation of Assets According to International Financial Reporting Standards

    Directory of Open Access Journals (Sweden)

    Jaunzeme Justine Sophia

    2016-06-01

    Full Text Available Application of discount rate in finance and accounting is founded on the concept of time value of money. Discounted cash flow model is widely used for asset valuation under the International Financial Reporting Standards (in abbreviation, IFRS. The discount rate applied in valuation models normally is the best rate of return that investors would earn alternative investments. With emergence of ecological economics as a separate branch of economics, the concept of ecological (or in other words, environmental discount rate has been elaborated. Muller (2013 in his paper ‘The Discounting Confusion: an Ecological Economics Perspective’, argues that traditional discounting can undermine long-term sustainability of the economy. In his work, Frank G. Muller considered adjusting the traditional discount rate in order to arrive at an environmental discount rate, which would help to ensure the sustainability of the economy. Hannon (2001 and Perrings (2001 in their paper ‘An Introduction to Spatial Discounting’ consider another variation of the discount rate - spatial discount rate. Spatial discount rate represents the rate at which the diffusion of environmental effects of economic activities is discounted over space. By February 2016, neither the application of environmental nor spatial discount rates under IFRS has been considered. The purpose of this paper is to analyse the implications that environmental and spatial discounting would have for the application of discounted cash flow model according to IFRS. The research methods applied are methods of economic analysis and synthesis.

  19. Implicit individual discount rate in China: A contingent valuation study.

    Science.gov (United States)

    Wang, Hua; He, Jie

    2018-03-15

    Two contingent valuation (CV) surveys were conducted in Kunming, China, to estimate households' willingness to pay (WTP) for the Panlong River rehabilitation project. The two surveys were conducted using the same procedures and questionnaires except for the payment schedule arrangements, which permitted a calculation of respondents' implicit discount rate. The surveys provided two estimates of WTP, one with a mean of 23 Yuan in monthly payment over 5 years and the other with a mean of 311 Yuan in a lump-sum payment that will cover all the expenses for a period of 5 years. The results produce an estimate of monthly discount rate of 7.6%-12.6% or annual discount rate of 141-315%. The estimates are higher than that reported from those studies conducted in the U.S., but are compatible with that of some other studies. This study also shows that both mean individual WTP and implicit individual discount rates are closely related to household demographic and economic characteristics and environment-related perceptions, as reported in the studies conducted in other countries. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Pension Fund Asset Allocation and Liability Discount Rates

    NARCIS (Netherlands)

    Andonov, Aleksandar; Bauer, Rob; Cremers, Martijn

    2017-01-01

    The unique regulation of U.S. public pension funds links their liability discount rate to the expected return on assets, which gives them incentives to invest more in risky assets in order to report a better funding status. Comparing public and private pension funds in the United States, Canada, and

  1. Choosing the Discount Rate for Defense Decisionmaking.

    Science.gov (United States)

    1976-07-01

    a weighted average of the after-personal-income-tax rate of return to savers and the pre- corporate - income - tax cost of capital. Stockfisch calcu].ates...occurs between the corporate and noncorporate sector. Many economists assume 100 percent shifting of the corporate income tax , so if the corporate ...capital is a weighted average of the after-personal-income-tax rate of return to savers and the pre- corporate - income - tax cost of capital. Stockfisch

  2. TEMPORAL INSENSITIVITY OF PVWTP AND IMPLIED DISCOUNT RATES IN CVM

    OpenAIRE

    Kim, Sooil; Haab, Timothy C.

    2003-01-01

    The sensitivity of WTP is tested in terms of the present value and the implied discount rates are derived by varying the length of benefit and the temporal payment schedules. Results show that holding the length of the project constant, the present value of willingness to pay does not vary significantly across payment schemes (one time payment, versus life of the project, versus perpetuity). Heteroskedasticity of error term over payment schemes fails to be accepted. Holding the payment scheme...

  3. 78 FR 67393 - Change in Discount Rate for Water Resources Planning

    Science.gov (United States)

    2013-11-12

    ... Discount Rate for Water Resources Planning AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of change. SUMMARY: The Water Resources Planning Act of 1965 and the Water Resources Development Act of 1974 require an annual determination of a discount rate for Federal water resources planning. The discount rate...

  4. 31 CFR 356.21 - How are awards at the high yield or discount rate calculated?

    Science.gov (United States)

    2010-07-01

    ... discount rate calculated? 356.21 Section 356.21 Money and Finance: Treasury Regulations Relating to Money... high yield or discount rate calculated? (a) Awards to submitters. We generally prorate bids at the highest accepted yield or discount rate under § 356.20(a)(2) of this part. For example, if 80.15% is the...

  5. Cash Flow and Discount Rate Risk in Up and Down Markets: What is actually priced?

    NARCIS (Netherlands)

    Botshekan, M.; Kraeussl, R.G.W.; Lucas, A.

    2012-01-01

    We test whether asymmetric preferences for losses versus gains affect the prices of cash flow versus discount rate risk. We construct a return decomposition distinguishing cash flow and discount rate betas in up and down markets. Using U.S. data, we find that downside cash flow and discount rate

  6. Manipulating the discount rate when valuing international investment projects

    Directory of Open Access Journals (Sweden)

    A. A. Medved

    2017-01-01

    Full Text Available The article deals with the practice of evaluation of international investment projects using the cash flow discounting rate. The problem of the discount rate manipulating is connected with the category “country risk”, which often determines the impact on the rate and, accordingly, the investment decisions. Critically examines existing approaches to the definition of “country risk”. Categories that make up a complete picture of “country risk” are distinguished. The general defect of existing country risk concepts is revealed – the fact that the measurements are based on rather subjective assessments and do not have sufficient empirical evidence, the fact that almost all of them have a clear liberal democratic bias: as a rule, drawing attention to the relationship between the political system and stability, the liberal democratic structure of society is recognized as the most stable, without any acceptable scientific evidence, followed by autocracy, military dictatorships and new independent states. The author affirms the lack of a clear and unambiguous definition of this category, the controversial approach to ranking of countries. The author analyzes and proves the bias of rating assigned by foreign companies. As a conclusion the need to create a national research concept of the “country risk” category is аffirms with the subsequent promotion of national rating agencies to the world market. The author's conception of the category “country risk” is proposed, an author's definition is given to this notion, it is recommended to establish the primacy of national ratings over foreign ones both in domestic and international relations in order to have independent influence on international capital flows. It is also proposed the evaluation of projects based on the dynamic discounting rates, especially for long-term strategic projects.

  7. Discount rate in the spent fuel storage and disposal fee

    International Nuclear Information System (INIS)

    Forster, J.D.; Cohen, S.

    1980-04-01

    After introducing the financial analyses, discount rates, and interest rates involved, the study discusses existing government guidelines for establishing charges for any service provided by the government to be paid by users of those services. Three current government user charges are analyzed including specifically their interest rate policies and how these charges provide precedent for the spent fuel acceptance and disposal fee: uranium enrichment services, the sale of electric power, and the delivery of experiments to orbit by the NASA Space Shuttle. The current DOE policy regarding this storage and disposal fee is stated and discussed. Features of this policy include: the full government cost is borne by users of the services provided; the fee is established and due in full at the time of spent fuel delivery; and the fee is adjusted when spent fuel is transferred from the AFR to the repository. Four evaluation criteria for use in analyzing the applications of discount rates in the spent fuel acceptance fee calculation are discussed. Three outstanding issues are discussed

  8. Incorporating a Time Horizon in Rate-of-Return Estimations: Discounted Cash Flow Model in Electric Transmission Rate Cases

    International Nuclear Information System (INIS)

    Chatterjee, Bishu; Sharp, Peter A.

    2006-01-01

    Electric transmission and other rate cases use a form of the discounted cash flow model with a single long-term growth rate to estimate rates of return on equity. It cannot incorporate information about the appropriate time horizon for which analysts' estimates of earnings growth have predictive powers. Only a non-constant growth model can explicitly recognize the importance of the time horizon in an ROE calculation. (author)

  9. Hypothetical intertemporal choice and real economic behavior: delay discounting predicts voucher redemptions during contingency-management procedures.

    Science.gov (United States)

    Bickel, Warren K; Jones, Bryan A; Landes, Reid D; Christensen, Darren R; Jackson, Lisa; Mancino, Michael

    2010-12-01

    Delay discounting rates are predictive of drug use status, the likelihood of becoming abstinent, and a variety of health behaviors. Rates of delay discounting may also be related to other relevant behaviors associated with addiction, such as the frequency at which individuals redeem contingency management voucher earnings. This study examined the discounting rates of 152 participants in a buprenorphine treatment program for opioid abuse. Participants received up to 12 weeks of buprenorphine treatment combined with contingency management. Participant's drug use was measured via urine specimens submitted three times a week. Successive negative urine specimens were reinforced with increasing amounts of money. After each negative urine specimen, a participant could either redeem his or her earnings or accumulate it in an account. Analysis of the frequency of redemptions showed that participants with higher rates of delay discounting at study intake redeemed their earnings significantly more often than participants with lower rates of discounting. Age and income also predicted redemption rates. We suggest that delay discounting rates can be used to predict redemption behaviors in a contingency management treatment program and that these findings are consistent with the recent theory of the competing neurobehavioral decision systems. PsycINFO Database Record (c) 2010 APA, all rights reserved.

  10. Individual discount rates and smoking: evidence from a field experiment in Denmark.

    Science.gov (United States)

    Harrison, Glenn W; Lau, Morten I; Rutström, E Elisabet

    2010-09-01

    We elicit measures of individual discount rates from a representative sample of the Danish population and test two substantive hypotheses. The first hypothesis is that smokers have higher individual discount rates than non-smokers. The second hypothesis is that smokers are more likely to have time inconsistent preferences than non-smokers, where time inconsistency is indicated by a hyperbolic discounting function. We control for the concavity of the utility function in our estimates of individual discount rates and find that male smokers have significantly higher discount rates than male non-smokers. However, smoking has no significant association with discount rates among women. This result is robust across exponential and hyperbolic discounting functions. We consider the sensitivity of our conclusions to a statistical specification that allows each observation to potentially be generated by more than one latent data-generating process. Copyright 2010 Elsevier B.V. All rights reserved.

  11. Heroin and cocaine abusers have higher discount rates for delayed rewards than alcoholics or non-drug-using controls.

    Science.gov (United States)

    Kirby, Kris N; Petry, Nancy M

    2004-04-01

    To test a prediction of the discounting model of impulsiveness that discount rates would be positively associated with addiction. The delay-discount rate refers to the rate of reduction in the present value of a future reward as the delay to that reward increases. We estimated participants' discount rates on the basis of their pattern of choices between smaller immediate rewards ($11-80) and larger, delayed rewards ($25-85; at delays from 1 week to 6 months) in a questionnaire format. Participants had a one-in-six chance of winning a reward that they chose on one randomly selected trial. Heroin (n = 27), cocaine (n = 41) and alcohol (n = 33) abusers and non-drug-using controls (n = 44) were recruited from advertisements. They were tested in a drug abuse research clinic at a medical school. On average, the cocaine and heroin groups had higher rates than controls (both P rates for heroin abusers (P = 0.03), but not for cocaine or alcohol abusers (both P > 0.50). These data suggest that discount rates vary with the preferred drug of abuse, and that high discount rates should be considered in the development of substance abuse prevention and treatment efforts.

  12. Commercial Discount Rate Estimation for Efficiency Standards Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Fujita, K. Sydny [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2016-04-13

    Underlying each of the Department of Energy's (DOE's) federal appliance and equipment standards are a set of complex analyses of the projected costs and benefits of regulation. Any new or amended standard must be designed to achieve significant additional energy conservation, provided that it is technologically feasible and economically justified (42 U.S.C. 6295(o)(2)(A)). A proposed standard is considered economically justified when its benefits exceed its burdens, as represented by the projected net present value of costs and benefits. DOE performs multiple analyses to evaluate the balance of costs and benefits of commercial appliance and equipment e efficiency standards, at the national and individual building or business level, each framed to capture different nuances of the complex impact of standards on the commercial end user population. The Life-Cycle Cost (LCC) analysis models the combined impact of appliance first cost and operating cost changes on a representative commercial building sample in order to identify the fraction of customers achieving LCC savings or incurring net cost at the considered efficiency levels.1 Thus, the choice of commercial discount rate value(s) used to calculate the present value of energy cost savings within the Life-Cycle Cost model implicitly plays a key role in estimating the economic impact of potential standard levels.2 This report is intended to provide a more in-depth discussion of the commercial discount rate estimation process than can be readily included in standard rulemaking Technical Support Documents (TSDs).

  13. Discount rates, equity weights and the social cost of carbon

    International Nuclear Information System (INIS)

    Hope, Chris

    2008-01-01

    Equity weighting has been proposed as a way of allowing welfare equivalents to be included in the social cost of carbon since a dollar to a poor person is worth more than a dollar to a rich one. Here we use the PAGE2002 integrated assessment model to show that the social cost of carbon is higher without equity weights (an elasticity of marginal utility with respect to income of 0) than with them. This might seem counter-intuitive, but it comes about because of the logical link between equity weights and discount rates; as the elasticity goes from 0 to - 0.5 to - 1.0, the social rate of time preference rises, and the drop in present values that results far outweighs the small increase in impacts that equity weights bring. (author)

  14. The WACC Fallacy: The Real Effects of Using a Unique Discount Rate

    OpenAIRE

    Krüger, Philipp; Landier, Augustin; Thesmar, David

    2011-01-01

    We document investment distortions induced by the use of a single discount rate within firms. According to textbook capital budgeting, firms should value any project using a discount rate determined by the risk characteristics of the project. If they use a unique company-wide discount rate, they overinvest (resp. underinvest) in divisions with a market beta higher (resp. lower) than the firm's core industry beta. We directly test this consequence of the WACC fallacy and establish a robust and...

  15. Heroin addicts have higher discount rates for delayed rewards than non-drug-using controls.

    Science.gov (United States)

    Kirby, K N; Petry, N M; Bickel, W K

    1999-03-01

    Fifty-six heroin addicts and 60 age-matched controls were offered choices between monetary rewards ($11-$80) available immediately and larger rewards ($25-$85) available after delays ranging from 1 week to 6 months. Participants had a 1-in-6 chance of winning a reward that they chose on one randomly selected trial. Delay-discounting rates were estimated from the pattern of participants' choices. The discounting model of impulsiveness (Ainslie, 1975) implies that delay-discounting rates are positively correlated with impulsiveness. On average, heroin addicts' discount rates were twice those of controls (p = .004), and discount rates were positively correlated with impulsivity as measured by self-report questionnaires (p discounting rate as a measure of impulsiveness, a characteristic associated with substance abuse.

  16. Philosophical origins of the social rate of discount in cost-benefit analysis.

    Science.gov (United States)

    Robinson, J C

    1990-01-01

    The social rate of discount--that is, the way decision makers today evaluate future consequences of collective activity--raises difficult issues of intergenerational justice. When benefits are discounted at the present rate the United States government requires, serious efforts to promote public health over the long term will fail cost-benefit tests. No consensus exists among theorists to establish fair rates; philosophers support discounting with economic arguments that economists reject, while economists no less paradoxically support the concept using philosophical arguments that philosophers disavow. A new emphasis on the role of consumers' and citizens' time preferences, however, will keep open rather than close debates on the social discount rate.

  17. Unique prediction of cannabis use severity and behaviors by delay discounting and behavioral economic demand.

    Science.gov (United States)

    Strickland, Justin C; Lile, Joshua A; Stoops, William W

    2017-07-01

    Few studies have simultaneously evaluated delay discounting and behavioral economic demand to determine their unique contribution to drug use. A recent study in cannabis users found that monetary delay discounting uniquely predicted cannabis dependence symptoms, whereas cannabis demand uniquely predicted use frequency. This study sought to replicate and extend this research by evaluating delay discounting and behavioral economic demand measures for multiple commodities and including a use quantity measure. Amazon.com's Mechanical Turk was used to sample individuals reporting recent cannabis use (n=64) and controls (n=72). Participants completed measures of monetary delay discounting as well as alcohol and cannabis delay discounting and demand. Cannabis users and controls did not differ on monetary delay discounting or alcohol delay discounting and demand. Among cannabis users, regression analyses indicated that cannabis delay discounting uniquely predicted use severity, whereas cannabis demand uniquely predicted use frequency and quantity. These effects remained significant after controlling for other delay discounting and demand measures. This research replicates previous outcomes relating delay discounting and demand with cannabis use and extends them by accounting for the contribution of multiple commodities. This research also demonstrates the ability of online crowdsourcing methods to complement traditional human laboratory techniques. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Investigation of the existing methodology of value estimation and methods of discount rate estimation

    OpenAIRE

    Plikus, Iryna

    2017-01-01

    The subject of research is the current practice of determining the fair value of assets and liabilities at the present (discounted) cost. One of the most problematic places is the determination of the discount rate, which belongs to the jurisdiction of a professional accountant judgment.The methods of formalization, hypothetical assumption, system approach and scientific abstraction in substantiating the formation of accounting policy with respect to the choice of the discount rate are used i...

  19. The consumption discount rate for the distant future (if we do not die out)

    NARCIS (Netherlands)

    Vermeylen, K.

    2013-01-01

    Gollier and Weitzman (2010) show that if future consumption discount rates are uncertain and persistent, the consumption discount rate should decline to its lowest possible value for events in the most distant future. In this paper, I argue that the lowest possible growth rate of consumption per

  20. 78 FR 16706 - Change in Discount Rate for Water Resources Planning

    Science.gov (United States)

    2013-03-18

    ... Planning AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of change. SUMMARY: The Water Resources Planning Act of 1965 and the Water Resources Development Act of 1974 require an annual determination of a discount rate for Federal water resources planning. The discount rate for Federal water resources planning...

  1. 75 FR 8106 - Change in Discount Rate for Water Resources Planning

    Science.gov (United States)

    2010-02-23

    ... Planning AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of change. SUMMARY: The Water Resources Planning Act of 1965 and the Water Resources Development Act of 1974 require an annual determination of a discount rate for Federal water resources planning. The discount rate for Federal water resources planning...

  2. 75 FR 82066 - Change in Discount Rate for Water Resources Planning

    Science.gov (United States)

    2010-12-29

    ... Planning AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of change. SUMMARY: The Water Resources Planning Act of 1965 and the Water Resources Development Act of 1974 require an annual determination of a discount rate for Federal water resources planning. The discount rate for Federal water resources planning...

  3. 76 FR 73674 - Change in Discount Rate for Water Resources Planning

    Science.gov (United States)

    2011-11-29

    ... Planning AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of change. SUMMARY: The Water Resources Planning Act of 1965 and the Water Resources Development Act of 1974 require an annual determination of a discount rate for Federal water resources planning. The discount rate for Federal water resources planning...

  4. 77 FR 1743 - Discount Rates for Cost-Effectiveness Analysis of Federal Programs

    Science.gov (United States)

    2012-01-11

    ... OFFICE OF MANAGEMENT AND BUDGET Discount Rates for Cost-Effectiveness Analysis of Federal Programs... Appendix C are to be used for cost-effectiveness analysis, including lease-purchase analysis, as specified... (Revised December 2011) Discount Rates for Cost-Effectiveness, Lease Purchase, and Related Analyses...

  5. 76 FR 7881 - Discount Rates for Cost-Effectiveness Analysis of Federal Programs

    Science.gov (United States)

    2011-02-11

    ... OFFICE OF MANAGEMENT AND BUDGET Discount Rates for Cost-Effectiveness Analysis of Federal Programs... Appendix C are to be used for cost-effectiveness analysis, including lease-purchase analysis, as specified... (Revised December 2010) DISCOUNT RATES FOR COST-EFFECTIVENESS, LEASE PURCHASE, AND RELATED ANALYSES...

  6. 78 FR 6140 - Discount Rates for Cost-Effectiveness Analysis of Federal Programs

    Science.gov (United States)

    2013-01-29

    ... OFFICE OF MANAGEMENT AND BUDGET Discount Rates for Cost-Effectiveness Analysis of Federal Programs... in Appendix C are to be used for cost-effectiveness analysis, including lease-purchase analysis, as...) Discount Rates for Cost-Effectiveness, Lease Purchase, and Related Analyses Effective Dates. This appendix...

  7. Long-term impacts of mega-projects: the discount rate

    NARCIS (Netherlands)

    Koopmans, C.; Rietveld, P.; Priemus, H.; van Wee, B.

    2013-01-01

    In social cost-benefit analysis (SCBA), discount rates are used to convert costs and benefits that occur at different points in time, to present values that can be added and subtracted. Especially if important costs and benefits occur in the long term (more than say 30 years), the discount rate may

  8. Temporal discounting rates and their relation to exercise behavior in older adults.

    Science.gov (United States)

    Tate, Linda M; Tsai, Pao-Feng; Landes, Reid D; Rettiganti, Mallikarjuna; Lefler, Leanne L

    2015-12-01

    As our nation's population ages, the rates of chronic illness and disability are expected to increase significantly. Despite the knowledge that exercise may prevent chronic disease and promote health among older adults, many still are inactive. Factors related to exercise behaviors have been explored in recent years. However, temporal discounting is a motivational concept that has not been explored in regard to exercise in older adults. Temporal discounting is a decision making process by which an individual chooses a smaller more immediate reward over a larger delayed reward. The aim of this study was to determine if temporal discounting rates vary between exercising and non-exercising older adults. This study used cross-sectional survey of 137 older adults living in the community. Older adults were recruited from 11 rural Arkansas churches. The Kirby delay-discounting Monetary Choice Questionnaire was used to collect discounting rates and then bivariate analysis was performed to compare temporal discounting rate between the exercisers and non-exercisers. Finally, multivariate analysis was used to compare discounting rate controlling for other covariates. The results indicated that exercising older adults display lower temporal discounting rates than non-exercising older adults. After controlling for education, exercisers still have lower temporal discounting rates than non-exercisers (phealth conditions relate to lack of exercise especially in older adults. This research suggests that if we can find appropriate incentives for discounting individuals, some type of immediate reward, then potentially we can design programs to engage and retain older adults in exercise. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Making the implicit explicit: A look inside the implicit discount rate

    International Nuclear Information System (INIS)

    Schleich, Joachim; Gassmann, Xavier; Faure, Corinne; Meissner, Thomas

    2016-01-01

    Implicit discount rates (IDRs) are employed in energy models to capture household investment decisions, yet the factors behind the IDR and their respective implications for policy-making usually remain blurred and fractional. The proposed comprehensive framework distinguishes three broad categories of factors underlying the IDR for household adoption of energy-efficient technologies (EETs): preferences (notably over time, risk, loss, debt, and the environment), predictable (ir)rational behavior (bounded rationality, rational inattention, behavioral biases), and external barriers to energy efficiency. Existing empirical findings suggest that the factors underlying the IDRs that differ across household characteristics and technologies should be accounted for in energy models. Furthermore, the framework allows for a fresh look at the interplay of IDRs and policies. We argue that a simple observation of high IDRs (or observing correlations between IDRs and socio-economic characteristics) does not provide guidance for policy-making since the underlying sources cannot be identified. Instead, we propose that some of the factors underlying the IDR - notably external barriers - can be changed (through directed policy interventions) whereas other factors - notably preferences and predictable (ir)rational behavior - are innate and can only be taken into account (through reactive policy interventions). - Highlights: • Implicit discount rates (IDRs) reflect preferences, predictable (ir)rational behaviors and external barriers. • The factors underlying the IDRs can be used to design directed and reactive policies. • IDRs in energy models should vary by household and technology characteristics.

  10. Harnessing the uncertainty monster: Putting quantitative constraints on the intergenerational social discount rate

    Science.gov (United States)

    Lewandowsky, Stephan; Freeman, Mark C.; Mann, Michael E.

    2017-09-01

    There is broad consensus among economists that unmitigated climate change will ultimately have adverse global economic consequences, that the costs of inaction will likely outweigh the cost of taking action, and that social planners should therefore put a price on carbon. However, there is considerable debate and uncertainty about the appropriate value of the social discount rate, that is the extent to which future damages should be discounted relative to mitigation costs incurred now. We briefly review the ethical issues surrounding the social discount rate and then report a simulation experiment that constrains the value of the discount rate by considering 4 sources of uncertainty and ambiguity: Scientific uncertainty about the extent of future warming, social uncertainty about future population and future economic development, political uncertainty about future mitigation trajectories, and ethical ambiguity about how much the welfare of future generations should be valued today. We compute a certainty-equivalent declining discount rate that accommodates all those sources of uncertainty and ambiguity. The forward (instantaneous) discount rate converges to a value near 0% by century's end and the spot (horizon) discount rate drops below 2% by 2100 and drops below previous estimates by 2070.

  11. Withdrawal-Related Changes in Delay Discounting Predict Short-Term Smoking Abstinence.

    Science.gov (United States)

    Miglin, Rickie; Kable, Joseph W; Bowers, Maureen E; Ashare, Rebecca L

    2017-06-01

    Impulsive decision making is associated with smoking behavior and reflects preferences for smaller, immediate rewards and intolerance of temporal delays. Nicotine withdrawal may alter impulsive decision making and time perception. However, little is known about whether withdrawal-related changes in decision making and time perception predict smoking relapse. Forty-five smokers (14 female) completed two laboratory sessions, one following 24-hour abstinence and one smoking-as-usual (order counterbalanced; biochemically verified abstinence). During each visit, participants completed measures of time perception, decision making (ie, discount rates), craving, and withdrawal. Following the second laboratory session, subjects underwent a well-validated model of short-term abstinence (quit week) with small monetary incentives for each day of biochemically confirmed abstinence. Smokers significantly overestimated time during abstinence, compared to smoking-as-usual (p = .021), but there were no abstinence effects on discount rates (p = .6). During the quit week, subjects were abstinent for 3.5 days (SD = 2.15) and smoked a total of 12.9 cigarettes (SD = 15.8). Importantly, higher discount rates (ie, preferences for immediate rewards) during abstinence (abstinence minus smoking difference score) predicted greater number of days abstinent (p = .01) and fewer cigarettes smoked during the quit week (p = .02). Withdrawal-related change in time reproduction did not predict relapse (p = .2). These data suggest that individuals who have a greater preference for immediate rewards during abstinence (vs. smoking-as-usual) may be more successful at maintaining short-term abstinence when provided with frequent (eg, daily) versus less frequent incentive schedules (eg, 1 month). Abstinence-induced changes in decision making may be important for identifying smokers who may benefit from interventions that incentivize abstinence such as contingency management (CM). The present results

  12. Benchmarking Discount Rate in Natural Resource Damage Assessment with Risk Aversion.

    Science.gov (United States)

    Wu, Desheng; Chen, Shuzhen

    2017-08-01

    Benchmarking a credible discount rate is of crucial importance in natural resource damage assessment (NRDA) and restoration evaluation. This article integrates a holistic framework of NRDA with prevailing low discount rate theory, and proposes a discount rate benchmarking decision support system based on service-specific risk aversion. The proposed approach has the flexibility of choosing appropriate discount rates for gauging long-term services, as opposed to decisions based simply on duration. It improves injury identification in NRDA since potential damages and side-effects to ecosystem services are revealed within the service-specific framework. A real embankment case study demonstrates valid implementation of the method. © 2017 Society for Risk Analysis.

  13. The discount rate in the economic evaluation of prevention: a thought experiment

    NARCIS (Netherlands)

    L.G.A. Bonneux (Luc); E. Birnie (Erwin)

    2001-01-01

    textabstractOBJECTIVES: In the standard economic model of evaluation, constant discount rates devalue the long term health benefits of prevention strongly. This study shows that it is unlikely that this reflects societal preference. DESIGN: A thought experiment in a

  14. Optimizing Discount Rates: Expressing Preferences for Sustainable Outcomes in Present Value Calculations

    OpenAIRE

    Axelrod, David

    2017-01-01

    This paper describes how the discount rate used in present value calculations expresses the preference for sustainability in decision making, and its implication for sustainable economic growth. In essence, the lower the discount rate, the greater the regard for the future, and the more likely we choose behaviors that lead to long-term sustainability. The theoretical framework combines behavioral economics and holonomics, which involve limitations of regard for the future due to constraints o...

  15. Assessing Discount Rate for a Project Financed Entirely with Equity Capital

    Directory of Open Access Journals (Sweden)

    Nicoleta Vintila

    2007-09-01

    Full Text Available Estimating discount rate for an investment project is one of the most challenging tasks incapital budgeting. In this paper we discuss different kind of models for cost of equity capital proposed infinance literature (static CAPM, conditional CAPM, APT, build-up model, focusing especially on advantagesand disadvantages of using each of them. In the final section, we estimate the discount rate fora certain project financed entirely with equity capital, using a version of build-up model.

  16. Discount rates in risk versus money and money versus money tradeoffs.

    Science.gov (United States)

    Alberini, Anna; Chiabai, Aline

    2007-04-01

    We use data from a survey of residents of five Italian cities conducted in late spring 2004 to estimate the discount rates implicit in (1) money versus future risk reductions and (2) money versus money tradeoffs. We find that the mean personal discount rate is 0.3-1.7% in (1) and 8.7% in (2). The latter is lower than the discount rates estimated in comparable situations in many recent studies, greater than market interest rates in Italy at the time, and exhibits modest variation with age and gender. The discount rate implicit in money versus risk tradeoffs is within the range of estimates from studies in the United States and Europe, and does not depend on observable individual characteristics. We use split samples to investigate whether a completely abstract risk reduction - one where the risk reduction delivery has been stripped of all specifics, so that respondents should focus on the risks without being distracted by details - results in WTP and discount figures comparable to those from an identified delivery mechanism (a medical test). We find that while WTP for an immediate risk reduction is 42-73% higher with the abstract risk reduction, the discount rate in the money versus risk tradeoffs and the variance of the error term in the WTP equation are the same across the two variants of the questionnaire.

  17. Optimal harvesting of fish stocks under a time-varying discount rate.

    Science.gov (United States)

    Duncan, Stephen; Hepburn, Cameron; Papachristodoulou, Antonis

    2011-01-21

    Optimal control theory has been extensively used to determine the optimal harvesting policy for renewable resources such as fish stocks. In such optimisations, it is common to maximise the discounted utility of harvesting over time, employing a constant time discount rate. However, evidence from human and animal behaviour suggests that we have evolved to employ discount rates which fall over time, often referred to as "hyperbolic discounting". This increases the weight on benefits in the distant future, which may appear to provide greater protection of resources for future generations, but also creates challenges of time-inconsistent plans. This paper examines harvesting plans when the discount rate declines over time. With a declining discount rate, the planner reduces stock levels in the early stages (when the discount rate is high) and intends to compensate by allowing the stock level to recover later (when the discount rate will be lower). Such a plan may be feasible and optimal, provided that the planner remains committed throughout. However, in practice there is a danger that such plans will be re-optimized and adjusted in the future. It is shown that repeatedly restarting the optimization can drive the stock level down to the point where the optimal policy is to harvest the stock to extinction. In short, a key contribution of this paper is to identify the surprising severity of the consequences flowing from incorporating a rather trivial, and widely prevalent, "non-rational" aspect of human behaviour into renewable resource management models. These ideas are related to the collapse of the Peruvian anchovy fishery in the 1970's. Copyright © 2010 Elsevier Ltd. All rights reserved.

  18. Reviewing and piloting methods for decreasing discount rates; someone, somewhere in time.

    Science.gov (United States)

    Parouty, Mehraj B Y; Krooshof, Daan G M; Westra, Tjalke A; Pechlivanoglou, Petros; Postma, Maarten J

    2013-08-01

    There has been substantial debate on the need for decreasing discounting for monetary and health gains in economic evaluations. Next to the discussion on differential discounting, a way to identify the need for such discounting strategies is through eliciting the time preferences for monetary and health outcomes. In this article, the authors investigate the perceived time preference for money and health gains through a pilot survey on Dutch university students using methods on functional forms previously suggested. Formal objectives of the study were to review such existing methods and to pilot them on a convenience sample using a questionnaire designed for this specific purpose. Indeed, a negative relation between the time of delay and the variance of the discounting rate for all models was observed. This study was intended as a pilot for a large-scale population-based investigation using the findings from this pilot on wording of the questionnaire, interpretation, scope and analytic framework.

  19. Predictive Validity of Delay Discounting Behavior in Adolescence: A Longitudinal Twin Study

    Science.gov (United States)

    Isen, Joshua D.; Sparks, Jordan C.; Iacono, William G.

    2014-01-01

    A standard assumption in the delay discounting literature is that individuals who exhibit steeper discounting of hypothetical rewards also experience greater difficulty deferring gratification to real-world rewards. There is ample cross-sectional evidence that delay discounting paradigms reflect a variety of maladaptive psychosocial outcomes, including substance use pathology. We sought to determine whether a computerized assessment of hypothetical delay discounting (HDD) taps into behavioral impulsivity in a community sample of adolescent twins (N = 675). Using a longitudinal design, we hypothesized that greater HDD at age 14–15 predicts real-world impulsive choices and risk for substance use disorders in late adolescence. We also examined the genetic and environmental structure of HDD performance. Individual differences in HDD behavior showed moderate heritability, and were prospectively associated with real-world temporal discounting at age 17–18. Contrary to expectations, HDD was not consistently related to substance use or trait impulsivity. Although a significant association between HDD behavior and past substance use emerged in males, this effect was mediated by cognitive ability. In both sexes, HDD failed to predict a comprehensive index of substance use problems and behavioral disinhibition in late adolescence. In sum, we present some of the first evidence that HDD performance is heritable and predictive of real-world temporal discounting of rewards. Nevertheless, HDD might not serve as a valid marker of substance use disorder risk in younger adolescents, particularly females. PMID:24999868

  20. THE DISCOUNT RATE POLICY IN ROMANIA IN THE 20TH CENTURY

    Directory of Open Access Journals (Sweden)

    Pociovalisteanu Diana

    2009-05-01

    Full Text Available Throughout the 20th century, economists have generally acknowledged the importance of the central bank discount rate as the reference interest rate in a country: by increasing the interest rate during economic booms that forego the busts, the Central Bank

  1. Time value of emission and technology discounting rate for off-grid electricity generation in India using intermediate pyrolysis

    International Nuclear Information System (INIS)

    Patel, Amit; Sarkar, Prabir; Tyagi, Himanshu; Singh, Harpreet

    2016-01-01

    The environmental impact assessment of a process over its entire operational lifespan is an important issue. Estimation of life cycle emission helps in predicting the contribution of a given process to abate (or to pollute) the environmental emission scenario. Considering diminishing and time-dependent effect of emission, assessment of the overall effect of emissions is very complex. The paper presents a generalized methodology for arriving at a single emission discounting number for a process option, using the concept of time value of carbon emission flow. This number incorporates the effect of the emission resulting from the process over the entire operational lifespan. The advantage of this method is its quantitative aspect as well as its flexible nature. It can be applied to any process. The method is demonstrated with the help of an Intermediate Pyrolysis process when used to generate off-grid electricity and opting biochar route for disposing straw residue. The scenarios of very high net emission to very high net carbon sequestration is generated using process by careful selection of process parameters for different scenarios. For these different scenarios, the process discounting rate was determined and its outcome is discussed. The paper also proposes a process specific eco-label that mentions the discounting rates. - Highlight: • Methodology to obtain emission discounting rate for a process is proposed. • The method includes all components of life cycle emission converts into a time dependent discounting number. • A case study of Intermediate Pyrolysis is used to obtain such number for a range of processes. • The method is useful to determine if the effect from the operation of a process will lead to a net absorption of emission or net accumulation of emission in the environment.

  2. Time value of emission and technology discounting rate for off-grid electricity generation in India using intermediate pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Amit, E-mail: amitrp@iitrpr.ac.in [Indian Institute of Technology Ropar, Nangal Road, Rupnagar 140001, Punjab (India); Faculty of Technology and Engineering, The Maharaja Sayajirao University of Baroda, Vadodara 390001, Gujarat (India); Sarkar, Prabir; Tyagi, Himanshu; Singh, Harpreet [Indian Institute of Technology Ropar, Nangal Road, Rupnagar 140001, Punjab (India)

    2016-07-15

    The environmental impact assessment of a process over its entire operational lifespan is an important issue. Estimation of life cycle emission helps in predicting the contribution of a given process to abate (or to pollute) the environmental emission scenario. Considering diminishing and time-dependent effect of emission, assessment of the overall effect of emissions is very complex. The paper presents a generalized methodology for arriving at a single emission discounting number for a process option, using the concept of time value of carbon emission flow. This number incorporates the effect of the emission resulting from the process over the entire operational lifespan. The advantage of this method is its quantitative aspect as well as its flexible nature. It can be applied to any process. The method is demonstrated with the help of an Intermediate Pyrolysis process when used to generate off-grid electricity and opting biochar route for disposing straw residue. The scenarios of very high net emission to very high net carbon sequestration is generated using process by careful selection of process parameters for different scenarios. For these different scenarios, the process discounting rate was determined and its outcome is discussed. The paper also proposes a process specific eco-label that mentions the discounting rates. - Highlight: • Methodology to obtain emission discounting rate for a process is proposed. • The method includes all components of life cycle emission converts into a time dependent discounting number. • A case study of Intermediate Pyrolysis is used to obtain such number for a range of processes. • The method is useful to determine if the effect from the operation of a process will lead to a net absorption of emission or net accumulation of emission in the environment.

  3. 77 FR 68886 - Rate for Use in Federal Debt Collection and Discount and Rebate Evaluation

    Science.gov (United States)

    2012-11-16

    ... DEPARTMENT OF THE TREASURY Fiscal Service Rate for Use in Federal Debt Collection and Discount and... responsible for computing and publishing the percentage rate to be used in assessing interest charges for outstanding debts owed to the Government. Treasury's Cash Management Requirements (TFM Volume I, Part 6...

  4. Stochastic Discount Factor Approach to International Risk-Sharing: Evidence from Fixed Exchange Rate Episodes

    NARCIS (Netherlands)

    Hadzi-Vaskov, M.; Kool, C.J.M.

    2007-01-01

    This paper presents evidence of the stochastic discount factor approach to international risk-sharing applied to fixed exchange rate regimes. We calculate risk-sharing indices for two episodes of fixed or very rigid exchange rates: the Eurozone before and after the introduction of the Euro, and

  5. The Effects of Inflation and Interest Rates on Delay Discounting in Human Behavior

    Science.gov (United States)

    Kawashima, Kentaro

    2006-01-01

    Interest and inflation rates may be major determinants of delay discounting, but these variables have not been controlled in past experiments because they depend on macroeconomic conditions. This study uses a computer game-like task to investigate the effects of inflation rates on people's subjective valuation of delayed rewards. During the task,…

  6. Impatience and Grades: Delay-Discount Rates Correlate Negatively with College Gpa

    Science.gov (United States)

    Kirby, K.N.; Winston, G.C.; Santiesteban, M.

    2005-01-01

    Because the rewards of academic performance in college are often delayed, the delay-discounting model of impulsiveness (Ainslie (1975) [Ainslie, G. Specious reward: A behavioral theory of impulsiveness and impulse control. Psychological Bulletin, 82 (4), 463-496] predicts that academic performance should tend to decrease as people place less…

  7. Discounting Behavior

    DEFF Research Database (Denmark)

    Andersen, Steffen; Harrison, Glenn W.; Lau, Morten

    2014-01-01

    We re-evaluate the theory, experimental design and econometrics behind claims that individuals exhibit non-constant discounting behavior. Theory points to the importance of controlling for the non-linearity of the utility function of individuals, since the discount rate is defined over time-dated...

  8. Economic rate of discount and estimating cost benefit of viral immunisation programmes.

    Science.gov (United States)

    West, R R

    1999-01-01

    Many individual and societal decisions over purchase (or investment) involve consideration of timing, in that either the price may be paid now and the benefit enjoyed some time in the future or the converse the benefit enjoyed now and the price paid later. Since most individuals generally prefer the present to the future, economic theory has conventionally discounted future costs or benefits to estimate 'net present values'. The rationale for this is principally based on future uncertainty. In recent years, economists have turned their attention to valuing health as an economic 'good'. Observations of individual behaviour would imply that individuals discount future health, as other potential benefits, mostly because there is some uncertainty about their futures. Although economic theory is strongly predicated on the 'sovereignty of the individual', it does not necessarily follow that society discounts the future as do individuals, since for society the future is not so uncertain. Society's endorsement of many public health and preventive medicine objectives, which seek health gains in the future (rather than the present), imply that society's rate of discount may be appreciably lower than that of individuals. In immunisation, arguably one of the most effective of preventive measures, there is the additional benefit to others attributable to herd immunity. This paper argues that the future health gains for society arising from immunisation should not be underestimated by application of inappropriate discounting.

  9. Focus on the future: Episodic future thinking reduces discount rate and snacking.

    Science.gov (United States)

    Dassen, Fania C M; Jansen, Anita; Nederkoorn, Chantal; Houben, Katrijn

    2016-01-01

    Obesity seems related to a preference for immediate gratification. By changing this focus on short term benefits to a more future-oriented outlook, delay discounting (impulsive decision making) can be changed by a manipulation of episodic future thinking (EFT). EFT comprises a vivid mental simulation of general future experiences. EFT may also affect consumption of unhealthy foods, which can be seen as a choice for immediate gratification. Recent research shows that future orientation should be tailored to the behavior at outcome. We therefore hypothesize that the effectiveness of EFT on food intake could be enhanced by making the content food-related. We conducted a 2 (future vs past thinking) by 2 (food vs non-food related thoughts) between-subject design experiment in female undergraduates (N = 94), to compare the efficacy of EFT versus the recalling of episodic past events in reducing discount rate and caloric intake. Content of imagery was either unrestricted or food-related. Participants engaged in EFT or control episodic imagery while snacks were offered to freely consume, and next the Monetary Choice Questionnaire was completed as a measure of delay discounting, while again being engaged in EFT or control imagery. Both types of EFT reduced delay discounting, however, only food-related EFT lead to more restricted caloric consumption. Thus, we found evidence that EFT reduced discount rate during decision making. However, in order to restrict caloric intake, EFT should entail food-related imagery. As discount rate and caloric intake were not related in the current sample, the underlying mechanism remains to be discovered. Results however suggest that EFT is a promising technique to resist immediate gratification. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Discount rates and the education gradient in mammography in the UK.

    Science.gov (United States)

    Bíró, Anikó

    2013-09-01

    I analyse intertemporal decisions on undertaking breast cancer screening by women aged 50-64  years in the UK and provide estimates of the rate of discounting potential future benefits of screening. I also analyse education differences in mammography decisions and examine the underlying mechanisms by which education influences breast cancer screening attendance. I estimate a structural model, which reveals that although there are differences in the disutility of breast cancer screening between education groups, there is no difference in the estimated discount factor. These results suggest that the observed education gradient is mainly due to differences in health behaviours and healthcare attitudes. Copyright © 2013 John Wiley & Sons, Ltd.

  11. Buyer-vendor coordination for fixed lifetime product with quantity discount under finite production rate

    Science.gov (United States)

    Zhang, Qinghong; Luo, Jianwen; Duan, Yongrui

    2016-03-01

    Buyer-vendor coordination has been widely addressed; however, the fixed lifetime of the product is seldom considered. In this paper, we study the coordination of an integrated production-inventory system with quantity discount for a fixed lifetime product under finite production rate and deterministic demand. We first derive the buyer's ordering policy and the vendor's production batch size in decentralised and centralised systems. We then compare the two systems and show the non-coordination of the ordering policies and the production batch sizes. To improve the supply chain efficiency, we propose quantity discount contract and prove that the contract can coordinate the buyer-vendor supply chain. Finally, we present analytically tractable solutions and give a numerical example to illustrate the benefits of the proposed quantity discount strategy.

  12. Dividend growth, cash flow, and discount rate news

    OpenAIRE

    Garrett, Ian; Priestley, Richard

    2012-01-01

    This is the authors’ accepted and refereed manuscript to the article. Publishers web site http://journals.cambridge.org/ Using a new variable based on a model of dividend smoothing, we find that dividend growth is highly predictable and that cash flow news contributes importantly to return variability. Cash flow betas derived from this predictability are central to explaining the size effect in the cross section of returns. However, they do not explain the value effect; this is explained b...

  13. 76 FR 72498 - Rate for Use in Federal Debt Collection and Discount and Rebate Evaluation

    Science.gov (United States)

    2011-11-23

    ... interest charges for outstanding debts owed to the Government. Treasury's Cash Management Requirements (TFM... DEPARTMENT OF THE TREASURY Fiscal Service Rate for Use in Federal Debt Collection and Discount and...: Pursuant to Section 11 of the Debt Collection Act of 1982, as amended, (31 U.S.C. 3717), the Secretary of...

  14. "Just Give Me a Number!" Practical Values for the Social Discount Rate

    Science.gov (United States)

    Moore, Mark A.; Boardman, Anthony E.; Vining, Aidan R.; Weimer, David L.; Greenberg, David H.

    2004-01-01

    A major reason the quality of cost-benefit analysis (CBA) varies widely is inconsistent use of the social discount rate (SDR). This article offers guidance about the choice of the SDR. Namely, we recommend the following procedures: If the project is intragenerational (does not have effects beyond 50 years) and there is no crowding out of private…

  15. The impact of education on subjective discount rate in Ugandan villages

    Czech Academy of Sciences Publication Activity Database

    Bauer, Michal; Chytilová, J.

    2010-01-01

    Roč. 58, č. 4 (2010), s. 643-669 ISSN 0013-0079 R&D Projects: GA MŠk LC542 Keywords : education * subjective discount rate * rural populations * Uganda Subject RIV: AH - Economics Impact factor: 1.392, year: 2010

  16. A note on high discount rates and depletion of primary forests

    NARCIS (Netherlands)

    Bulte, E; vanSoest, D

    1996-01-01

    Conventional wisdom implies that high discount rates accelerate depletion of tropical forests. As shown in this article, this result does not necessarily hold in a two-state variable model that distinguishes between primary and secondary forest stocks. In the context of a fixed concession period and

  17. Tables of compound-discount interest rate multipliers for evaluating forestry investments.

    Science.gov (United States)

    Allen L. Lundgren

    1971-01-01

    Tables, prepared by computer, are presented for 10 selected compound-discount interest rate multipliers commonly used in financial analyses of forestry investments. Two set of tables are given for each of the 10 multipliers. The first set gives multipliers for each year from 1 to 40 years; the second set gives multipliers at 5-year intervals from 5 to 160 years....

  18. The Discount Rate for Defense Decisionmaking: Some New Considerations,

    Science.gov (United States)

    1978-11-01

    the pre- corporate - income - tax cost of capital. Stockfisch calculates the pre-tax rate of return in several corporate sectors and takes a weighted average...economists assume 100 percent shifting of the corporate income tax , so if the corporate income tax is 50 percent, then the rate of return in the

  19. Implicit discount rates of vascular surgeons in the management of abdominal aortic aneurysms.

    Science.gov (United States)

    Enemark, U; Lyttkens, C H; Troëng, T; Weibull, H; Ranstam, J

    1998-01-01

    A growing empirical literature has investigated attitudes towards discounting of health benefits with regard to social choices of life-saving and health-improving measures and individuals' time preferences for the management of their own health. In this study, the authors elicited the time preferences of vascular surgeons in the context of management of small abdominal aortic aneurysms, for which the choice between early elective surgery and watchful waiting is not straightforward. They interviewed 25 of a random sample of 30 Swedish vascular surgeons. Considerable variation in the time preferences was found in the choices between watchful waiting and surgical intervention among the otherwise very homogeneous group of surgeons. The discount rates derived ranged from 5.3% to 19.4%. The median discount rate (10.4%) is similar to those usually reported for social choices concerning life-saving measures. The surgeons who were employed in university hospitals had higher discount rates than did their colleagues in county and district hospitals.

  20. Delay Discounting Rates Are Temporally Stable in an Equivalent Present Value Procedure Using Theoretical and Area under the Curve Analyses

    Science.gov (United States)

    Harrison, Justin; McKay, Ryan

    2012-01-01

    Temporal discounting rates have become a popular dependent variable in social science research. While choice procedures are commonly employed to measure discounting rates, equivalent present value (EPV) procedures may be more sensitive to experimental manipulation. However, their use has been impeded by the absence of test-retest reliability data.…

  1. 75 FR 61747 - Discount Energy Group, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes...

    Science.gov (United States)

    2010-10-06

    ... proceeding of Discount Energy Group, LLC's application for market-based rate authority, with an accompanying... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER10-2803-000] Discount Energy Group, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for Blanket...

  2. ChargeOut! : discounted cash flow compared with traditional machine-rate analysis

    Science.gov (United States)

    Ted Bilek

    2008-01-01

    ChargeOut!, a discounted cash-flow methodology in spreadsheet format for analyzing machine costs, is compared with traditional machine-rate methodologies. Four machine-rate models are compared and a common data set representative of logging skidders’ costs is used to illustrate the differences between ChargeOut! and the machine-rate methods. The study found that the...

  3. Stated time preferences for health: a systematic review and meta analysis of private and social discount rates.

    Science.gov (United States)

    Mahboub-Ahari, Alireza; Pourreza, Abolghasem; Sari, Ali Akbari; Rahimi Foroushani, Abbas; Heydari, Hassan

    2014-01-01

    The present study aimed to provide better insight on methodological issues related to time preference studies, and to estimate private and social discount rates, using a rigorous systematic review and meta-analysis. We searched PubMed, EMBASE and Proquest databases in June 2013. All studies had estimated private and social time preference rates for health outcomes through stated preference approach, recognized eligible for inclusion. We conducted both fixed and random effect meta-analyses using mean discount rate and standard deviation of the included studies. I-square statistics was used for testing heterogeneity of the studies. Private and social discount rates were estimated separately via Stata11 software. Out of 44 screened full texts, 8 population-based empirical studies were included in qualitative synthesis. Reported time preference rates for own health were from 0.036 to 0.07 and for social health from 0.04 to 0.2. Private and social discount rates were estimated at 0.056 (95% CI: 0.038, 0.074) and 0.066 (95% CI: 0.064, 0.068), respectively. Considering the impact of time preference on healthy behaviors and because of timing issues, individual's time preference as a key determinant of policy making should be taken into account. Direct translation of elicited discount rates to the official discount rates has been remained questionable. Decisions about the proper discount rate for health context, may need a cross-party consensus among health economists and policy makers.

  4. A Social Discount Rate for Climate Damage to Future Generations Based on Regulatory Law

    Energy Technology Data Exchange (ETDEWEB)

    Davidson, M.D. [Department of Philosophy, Faculty of Humanities, University of Amsterdam, Nieuwe Doelenstraat 15, 1012 CP Amsterdam (Netherlands)

    2006-05-15

    This article examines the implications for the social discount rate for damage due to climate change if risk to future generations is handled in accordance with the laws regulating our handling of risk to contemporaries. The conclusions are the following. Under current law, neither geographic distance nor differences in wealth between risk creator and risk bearer play any part in establishing a standard of 'reasonable care'. The concept of intergenerational justice requires these same principles to be applied in the intergenerational context too, implying a zero consumption rate of interest for climate damage. Assuming that the extent to which mitigation is at the expense of alternative investments is equal to society's marginal propensity to save, the social discount rate becomes society's marginal propensity to save times the long-term market rate of return on private investment, implying a social discount rate of around one per cent or a fraction of one per cent. This formula is exact under the assumption of average saving behaviour and by attributing consumption losses due to investment in damage prevention before damage occurs to the risk creator and after damage occurs to the risk bearer.

  5. The Dividend Discount Model with Multiple Growth Rates of Any Order for Stock Evaluation

    OpenAIRE

    Hatemi-J, Abdulnasser; El-Khatib, Youssef

    2018-01-01

    In this paper we provide a general solution for the dividend discount model in order to compute the intrinsic value of a common stock that allows for multiple stage growth rates of any predetermined number of periods. A mathematical proof is provided for the suggested general solution. A numerical application is also presented. The solution introduced in this paper is expected to improve on the precision of stock valuation, which might be of fundamental importance for investors as well as fin...

  6. The discount rate in the economic evaluation of prevention: a thought experiment.

    Science.gov (United States)

    Bonneux, L; Birnie, E

    2001-02-01

    In the standard economic model of evaluation, constant discount rates devalue the long term health benefits of prevention strongly. This study shows that it is unlikely that this reflects societal preference. A thought experiment in a cause elimination life table calculates savings of eliminating cardiovascular disease from the Dutch population. A cost effectiveness analysis calculates the acceptable costs of such an intervention at a threshold of 18 000 Euro per saved life year. Cause specific mortality (all cardiovascular causes of death and all other causes) and health care costs (all costs of cardiovascular disease and all other causes of costs) by age and male sex of 1994. At a 0% discount rate, an intervention eliminating cardiovascular disease may cost 71 100 Euro. At the same threshold but at discount rates of 3% or 6%, the same intervention may cost 8100 Euro (8.8 times less) or 1100 Euro (65 times less). The standard economic model needs more realistic duration dependent models of time preference, which reflect societal preference.

  7. Results of reference pricing and reimbursement discount rate schemes of Turkey

    Directory of Open Access Journals (Sweden)

    Guvenc Kockaya

    2013-06-01

    Full Text Available OBJECTIVES: General Directorate of Pharmaceuticals and Pharmacy (IEGM is responsible for setting all prices for human medicinal products. The reference pricing system is used for setting these prices. Reference countries are reviewed annually and may be subject to certain alterations. There were 5 reference countries in 2009: Spain, Italy, Germany, France and Greece. The aim of this study is to show the distribution of reference countries which were used for reference pricing.METHODS: The price list of pharmaceuticals which was published by IEGM on 15.04.2011 was used for analysis. Distribution of reference countries and prices were evaluated.RESULTS: Prices of 6,251 generic and 3,703 original products were set according to the price list. 5,283 of generics and 3,306 of originals were in the positive list for reimbursement. Reference pricing was used for 2,352 generics and 2,281 originals. Prices of the remaining were set outside of reference pricing. 32 different countries were used for reference pricing. Italy was the most popular country for reference pricing. Even if it was not a reference country, Germany was used in some of the pharmaceuticals. The average reimbursement discount rate and price were 24.43% and 249 TL, respectively. There were no colerations between price and reimbursement discount rate, or reference country and reimbursement rate.CONCLUSION: It has been shown that Italy has the highest impact on the pricing of all pharmaceuticals in Turkey. Even if it was not a reference country, Germany showed to affect pharmaceuticals more than other countries which were also not used for reference pricing. Even if reimbursement discount rates are stated by the Social Security Institution (SGK, there are different discount rates for pharmaceuticals. The analysis stated that there were correlation between price, country and discount rates. This analysis is first for the literature. Further analysis is necessary in the light of price

  8. Financial modeling in medicine: cash flow, basic metrics, the time value of money, discount rates, and internal rate of return.

    Science.gov (United States)

    Lexa, Frank James; Berlin, Jonathan W

    2005-03-01

    In this article, the authors cover tools for financial modeling. Commonly used time lines and cash flow diagrams are discussed. Commonly used but limited terms such as payback and breakeven are introduced. The important topics of the time value of money and discount rates are introduced to lay the foundation for their use in modeling and in more advanced metrics such as the internal rate of return. Finally, the authors broach the more sophisticated topic of net present value.

  9. Temporal framing and the hidden-zero effect: rate-dependent outcomes on delay discounting.

    Science.gov (United States)

    Naudé, Gideon P; Kaplan, Brent A; Reed, Derek D; Henley, Amy J; DiGennaro Reed, Florence D

    2018-05-01

    Recent research suggests that presenting time intervals as units (e.g., days) or as specific dates, can modulate the degree to which humans discount delayed outcomes. Another framing effect involves explicitly stating that choosing a smaller-sooner reward is mutually exclusive to receiving a larger-later reward, thus presenting choices as an extended sequence. In Experiment 1, participants (N = 201) recruited from Amazon Mechanical Turk completed the Monetary Choice Questionnaire in a 2 (delay framing) by 2 (zero framing) design. Regression suggested a main effect of delay, but not zero, framing after accounting for other demographic variables and manipulations. We observed a rate-dependent effect for the date-framing group, such that those with initially steep discounting exhibited greater sensitivity to the manipulation than those with initially shallow discounting. Subsequent analyses suggest these effects cannot be explained by regression to the mean. Experiment 2 addressed the possibility that the null effect of zero framing was due to within-subject exposure to the hidden- and explicit-zero conditions. A new Amazon Mechanical Turk sample completed the Monetary Choice Questionnaire in either hidden- or explicit-zero formats. Analyses revealed a main effect of reward magnitude, but not zero framing, suggesting potential limitations to the generality of the hidden-zero effect. © 2018 Society for the Experimental Analysis of Behavior.

  10. Towards a social discount rate for the economic evaluation of health technologies in Germany: an exploratory analysis.

    Science.gov (United States)

    Schad, Mareike; John, Jürgen

    2012-04-01

    Over the last decades, methods for the economic evaluation of health care technologies were increasingly used to inform reimbursement decisions. For a short time, the German Statutory Health Insurance makes use of these methods to support reimbursement decisions on patented drugs. In this context, the discounting procedure emerges as a critical component of these methods, as discount rates can strongly affect the resulting incremental cost-effectiveness ratios. The aim of this paper is to identify the appropriate value of a social discount rate to be used by the German Statutory Health Insurance for the economic evaluation of health technologies. On theoretical grounds, we build on the widespread view of contemporary economists that the social rate of time preference (SRTP) is the adequate social discount rate. For quantifying the SRTP, we first apply the market behaviour approach, which assumes that the SRTP is reflected in observable market interest rates. As a second approach, we derive the SRTP from optimal growth theory by using the Ramsey equation. A major part of the paper is devoted to specify the parameters of this equation. Depending on various assumptions, our empirical findings result in the range of 1.75-4.2% for the SRTP. A reasonable base case discount rate for Germany, thus, would be about 3%. Furthermore, we deal with the much debated question whether a common discount rate for costs and health benefits or a lower rate for health should be applied in health economic evaluations. In the German social health insurance system, no exogenously fixed budget constraint does exist. When evaluating a new health technology, the health care decision maker is obliged to conduct an economic evaluation in order to examine whether there is an economically appropriate relation between the value of the health gains and the additional costs which are given by the value of the consumption losses due to the additional health care expenditures. Therefore, a discount

  11. The discount rate and the value of remaining years of life

    OpenAIRE

    Hartwick, John

    2008-01-01

    We back out an estimate of a personal discount rate of between 3 and 4 percent for a person with a life expectancy of 74 years who dies at age 30 (or 40) and has a value of statistical life of $6.3 million. Central to these calculations is the series generated by Murphy and Topel of value of life years (the dollar value of consumption plus the dollar value of leisure, with some smoothing for income in retirement). We employ the Makeham "model" of life expectancy in our calculations.

  12. The effect of discounting, different mortality reduction schemes and predictive cohort life tables on risk acceptability criteria

    International Nuclear Information System (INIS)

    Rackwitz, Ruediger

    2006-01-01

    Technical facilities should be optimal with respect to benefits and cost. Optimization of technical facilities involving risks for human life and limb require an acceptability criterion and suitable discount rates both for the public and the operator depending on for whom the optimization is carried out. The life quality index is presented and embedded into modem socio-economic concepts. A general risk acceptability criterion is derived. The societal life saving cost to be used in optimization as life saving or compensation cost and the societal willingness-to-pay based on the societal value of a statistical life or on the societal life quality index are developed. Different mortality reduction schemes are studied. Also, predictive cohort life tables are derived and applied. Discount rates γ must be long-term averages in view of the time horizon of some 20 to more than 100 years for the facilities of interest and net of inflation and taxes. While the operator may use long-term averages from the financial market for his cost-benefit analysis the assessment of interest rates for investments of the public into risk reduction is more difficult. The classical Ramsey model decomposes the real interest rate (=output growth rate) into the rate of time preference of consumption and the rate of economical growth multiplied by the elasticity of marginal utility of consumption. It is proposed to use a relatively small interest rate of 3% implying a rate of time preference of consumption of about 1%. This appears intergenerationally acceptable from an ethical point of view. Risk-consequence curves are derived for an example

  13. Discounting in Economic Evaluations.

    Science.gov (United States)

    Attema, Arthur E; Brouwer, Werner B F; Claxton, Karl

    2018-05-19

    Appropriate discounting rules in economic evaluations have received considerable attention in the literature and in national guidelines for economic evaluations. Rightfully so, as discounting can be quite influential on the outcomes of economic evaluations. The most prominent controversies regarding discounting involve the basis for and height of the discount rate, whether costs and effects should be discounted at the same rate, and whether discount rates should decline or stay constant over time. Moreover, the choice for discount rules depends on the decision context one adopts as the most relevant. In this article, we review these issues and debates, and describe and discuss the current discounting recommendations of the countries publishing their national guidelines. We finish the article by proposing a research agenda.

  14. Influence of the discount rate when comparing costs of different nuclear fuel cycles

    International Nuclear Information System (INIS)

    Le Dars, A.; Loaec, Ch.

    2007-01-01

    The article describes the methodology and technical economic results obtained by Cea in the DERECO project. This project was aimed at evaluating ground-breaking and intricate scenarios of the nuclear fuel cycle, and developed on the long term (150 years), in the context of France. All 5 scenarios studied assume that the reliance on nuclear energy will continue in order to satisfy the electricity demand. Despite uncertainties, the trends are breaking free from the analysis. It appears that the scenarios in which fourth generation fast reactors take part are globally more economical than the keeping to the present strategy of plutonium mono-recycling in PWR. The scenario in which fuel reprocessing is stopped has a total cost concerning the fuel cycle similar to that of the present strategy but the disposal cost is twice as high because of the necessity of disposing spent fuels directly in geological formations. The comparative costs of the different scenarios are set out and the influence of the discount rate is highlighted. One must keep in mind that the actualization theory entails a diminishing value for long term costs due to an unavoidable mechanical effect of the discount rate

  15. Delayed discounting and hedonic hunger in the prediction of lab-based eating behavior.

    Science.gov (United States)

    Ely, Alice V; Howard, Janna; Lowe, Michael R

    2015-12-01

    Research suggests that characteristics identified in obese individuals, such as impulsive decision-making and hedonic hunger, may exist in nonobese populations. This study examined the independent and interactive effects of impulsive decision-making (measured via delay discounting, DD) and hedonic hunger (assessed with the Power of Food Scale, PFS) on food intake. Female participants (N=78) ate a self-determined amount of plain oatmeal, completed self-report measures and the delay discounting task, and participated in a sham taste test of palatable sweet and salty foods. Unexpectedly, PFS and DD scores interacted to predict consumption of the total amount of food consumed, and of oatmeal alone, but not of snack food alone. High-PFS participants consumed more when also high in DD, while low-PFS participants showed the opposite pattern of consumption. The findings identify variables that may increase propensity toward overconsumption and potential weight gain; future research is necessary to evaluate the utility of these constructs to predict increases in BMI over time. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Discounting and nuclear power

    International Nuclear Information System (INIS)

    Jones, P.M.S.

    1984-01-01

    The paper describes the practice of discounting and its applicability to nuclear power, and the choice of discount rates. Opportunity cost of capital; risk; social time preference; intergenerational equity; non-monetary aspects; and discounting and nuclear energy; are all discussed. (U.K.)

  17. Tracking the Discount: Tuition Discount Rates, Net Tuition Revenue, and Efforts to Inform Institutional Practices. Professional File. Article 133, Fall 2013

    Science.gov (United States)

    Davis, Natalie Pullaro; Redd, Kenneth E.

    2013-01-01

    This article uses findings from the 2012 Tuition Discounting Study (TDS) conducted by the National Association of College and University Business Officers (NACUBO) to provide a framework for institutional researchers to develop and adapt their own custom tuition discounting definitions and formulas. Under tuition discounting, colleges and…

  18. 78 FR 65430 - Notice of Rate To Be Used for Federal Debt Collection, and Discount and Rebate Evaluation

    Science.gov (United States)

    2013-10-31

    ... assessing interest charges for outstanding debts owed to the Government (The Debt Collection Act of 1982, as... DEPARTMENT OF THE TREASURY Fiscal Service Notice of Rate To Be Used for Federal Debt Collection... rate to be used for Federal debt collection, and discount and rebate evaluation. SUMMARY: The Secretary...

  19. ChargeOut! : determining machine and capital equipment charge-out rates using discounted cash-flow analysis

    Science.gov (United States)

    E.M. (Ted) Bilek

    2007-01-01

    The model ChargeOut! was developed to determine charge-out rates or rates of return for machines and capital equipment. This paper introduces a costing methodology and applies it to a piece of capital equipment. Although designed for the forest industry, the methodology is readily transferable to other sectors. Based on discounted cash-flow analysis, ChargeOut!...

  20. The impact of building orientation and discount rates on a Portuguese reference building refurbishment decision

    International Nuclear Information System (INIS)

    Brandão de Vasconcelos, Ana; Cabaço, António; Pinheiro, Manuel Duarte; Manso, Armando

    2016-01-01

    Refurbishment, as part of the construction industry, has a strong global impact, not only from the viewpoint of economies but also from social and energy-efficiency perspectives. A thermal refurbishment process, in particular, involves numerous decisions and choices; the decision-makers being ultimately confronted with two major questions: which criterion should be adopted in the choice of the refurbishment construction solutions and which refurbishment construction solutions should be chosen? In this paper, a criterion based on technical and economic points of view is proposed, aiming to identify the cost-optimal package of energy efficient solutions from among a set of possible refurbishment measures, within the life cycle of buildings. Sensitivity analyses are also performed so that the results may help the decision-maker choose the appropriate refurbishment solutions to be adopted when different discount rates and building orientations are taken into consideration. A total of seven scenarios, for a macroeconomic perspective, and nine, for a financial perspective, are performed. The costoptimal methodology adopted, following the Directive 2010/31/EU (2010) recommendations, is applied to a Portuguese reference building. The analysis carried out allows obtaining low global life cycle costs solutions and points towards nearly Zero Energy Building (nZEB) concept. The results are important for drawing national political instruments on buildings energy efficiency. - Highlights: •Building refurbishment decision based on technical and economic points of view. •35.000 Packages of thermal rehabilitation solutions considered. •Building orientation and discount rate impact on the cost-optimal package of solutions. •Portuguese reference building case base.

  1. Determining a Relationship between Higher Education Financial Position and Tuition Discount Rates

    Science.gov (United States)

    Browning, Julianna

    2013-01-01

    Institutions have increased the practice of tuition discounting, that is, the strategic use of price discrimination. During the past 30 years, both the average percent discount given to students and the proportion of students receiving tuition breaks have increased. As this practice has increased, there are financial determinants and implications…

  2. Effects of Gainsharing Provisions on the Selection of a Discount Rate for a Defined Benefit Pension Plan

    Directory of Open Access Journals (Sweden)

    Robert J. Rietz

    2017-06-01

    Full Text Available This paper examines the effect of gainsharing provisions on the selection of a discount rate for a defined benefit pension plan. The paper uses a traditional actuarial approach of discounting liabilities using the expected return of the associated pension fund. A stochastic Excel model was developed to simulate the effect of varying investment returns on a pension fund with four asset classes. Lognormal distributions were fitted to historical returns of two of the asset classes; large company stocks and long-term government bonds. A third lognormal distribution was designed to represent the investment returns of alternative investments, such as real estate and private equity. The fourth asset class represented short term cash investments and that return was held constant. The following variables were analyzed to determine their relative impact of gainsharing on the selection of a discount rate: hurdle rate, percentage of gainsharing, actuarial asset method smoothing period, and variations in asset allocation. A 50% gainsharing feature can reduce the discount rate for a defined benefit pension plan from 0.5% to more than 2.5%, depending on the gainsharing design and asset allocation.

  3. Intergenerational discounting

    International Nuclear Information System (INIS)

    Schelling, T.C.

    1995-01-01

    A ''discount rate'' for the consumption of future generations from current investments for their benefit is typically composed of two parts: ''time preference'' and an allowance for the lower marginal utility of consumption due to higher average levels of consumption in the future. Time preference would be involved if one were postponing one's own consumption; it has little or nothing to do with income redistribution, which is what greenhouse abatement is about. A lower marginal utility of consumption is an anomaly in income redistribution: we rarely deliberately transfer consumption from the less to the more well-to-do. Time may serve as a kind of measure of distance; we may prefer beneficiaries who are closer in time, in geographical distance, in culture, surely in kinship. Perhaps to keep our thinking straight we should use a term like ''depreciation'', rather than ''discounting''. (Author)

  4. On the social rate of discount: the case for macroenvironmental policy

    Energy Technology Data Exchange (ETDEWEB)

    Doeleman, J.A.

    Concern for the rapidly growing scale and intensity of the human exploitation of the environment, in particular the alienation of natural ecosystems, but also resource exhaustion, pollution, and congestion, leads one to wonder about the short time horizons allowed for in decision making. Time preference is dictated by the rate of interest, allowing in practice a horizon often not exceeding several decades. I argue that this is unsatisfactory. Some minimal social rate of discount should not be enforced. Instead, it is more feasible to set absolute environmental standards, thereby introducing quantity constraints on our decision making, within which time preference can be permitted to find its own level. This acknowledges that the myopia of human vision may not be a flaw but rather a biological design which has served us well in evolution. It may, therefore, be better to change the rules by introducing self-imposed collective constraints than to try to change the shortsightedness of people in their day-to-day grass-roots decision making.

  5. Positive mood effects on delay discounting.

    Science.gov (United States)

    Hirsh, Jacob B; Guindon, Alex; Morisano, Dominique; Peterson, Jordan B

    2010-10-01

    Delay discounting is the process by which the value of an expected reward decreases as the delay to obtaining that reward increases. Individuals with higher discounting rates tend to prefer smaller immediate rewards over larger delayed rewards. Previous research has indicated that personality can influence an individual's discounting rates, with higher levels of Extraversion predicting a preference for immediate gratification. The current study examined how this relationship would be influenced by situational mood inductions. While main effects were observed for both Extraversion and cognitive ability in the prediction of discounting rates, a significant interaction was also observed between Extraversion and positive affect. Extraverted individuals were more likely to prefer an immediate reward when first put in a positive mood. Extraverts thus appear particularly sensitive to impulsive, incentive-reward-driven behavior by temperament and by situational factors heightening positive affect. (PsycINFO Database Record (c) 2010 APA, all rights reserved).

  6. Individual differences in discount rate are associated with demand for self-administered cocaine, but not sucrose.

    Science.gov (United States)

    Koffarnus, Mikhail N; Woods, James H

    2013-01-01

    Substance abusers, including cocaine abusers, discount delayed rewards to a greater extent than do matched controls. In the current experiment, individual differences in discounting of delayed rewards in rats (choice of one immediate over three delayed sucrose pellets) were assessed for associations with demand for either sucrose pellets or an intravenous dose of 0.1 mg/kg/infusion cocaine. Twenty-four male Sprague Dawley rats were split into three groups based on sensitivity to delay to reinforcement. Then, demand for sucrose pellets and cocaine was determined across a range of fixed-ratio values. Delay discounting was then reassessed to determine the stability of this measure over the course of the experiment. Individual differences in impulsive choice were positively associated with elasticity of demand for cocaine, a measure of reinforcer value, indicating that rats having higher discount rates also valued cocaine more. Impulsive choice was not associated with the level of cocaine consumption as price approached 0 or with any parameter associated with demand for sucrose. Individual sensitivity to delay was correlated with the initial assessment when reassessed at the end of the experiment, although impulsive choice increased for this cohort of rats as a whole. These findings suggest that impulsive choice in rats is positively associated with valuation of cocaine, but not sucrose. © 2011 The Authors, Addiction Biology © 2011 Society for the Study of Addiction.

  7. Discounting and Expropriation Risk

    OpenAIRE

    Giovanni Immordino; Mario Padula

    2007-01-01

    This paper investigates the association between discounting and risk of expropriation and provides the theoretical conditions that make a positive association consistent with rationality. Moreover, using a national representative sample and a representative sample of the 50+ in eleven European countries, we show that discounting increases with expropriation risk. The two surveys give direct measures of discount rate as well as measures derived from households consumption decisions and provide...

  8. Cognitive Procedures and Hyperbolic Discounting

    NARCIS (Netherlands)

    Nir, A.

    2004-01-01

    "Hyperbolic discount functions are characterized by a relatively high discount rate over short horizons and a relatively low discount rate over long horizons" (Laibson 1997).We suggest two cognitive procedures where individuals perceive future utility as decreasing at a decreasing rate as a function

  9. Concordance between monetary and sexual delay discounting in men who have sex with men.

    Science.gov (United States)

    Jones, Jeb; Guest, Jodie L; Sullivan, Patrick S; Kramer, Michael R; Jenness, Samuel M; Sales, Jessica M

    2017-12-07

    Background: Delay discounting has been found to be associated with numerous health-related outcomes, including risky sexual behaviour. To date, it is unclear whether delay discounting measured in different domains is associated within individuals. The goal of this study was to assess the concordance of monetary and sexual delay discounting in men who have sex with men. Methods: Participants completed an online survey, including the Monetary Choice Questionnaire and the Sexual Discounting Task. Linear regression models were used to assess the association between monetary and sexual discount rates. Results: Sexual discount rates did not predict monetary discount rates. There was a substantial amount of clustering of sexual discount rates, requiring sexual discounting data to be categorised. Conclusions: Monetary and sexual delay discounting are distinct processes that are not necessarily associated within individuals, and monetary delay discounting is not an appropriate proxy measure for sexual impulsivity. Data from the Sexual Discounting Task are typically rank-transformed for analysis. These data suggest that this might be an invalid method of analysis. Future studies should investigate the distribution of their data to determine if it is appropriate to analyse sexual discounting data as a continuous measure.

  10. The Choice of Discount Rate Applicable to Government Resource Use: Theory and Limitations

    Science.gov (United States)

    1987-12-01

    that postulates "the greatest good for the greatest number," as expressed by Jeremy Bentham in 1789. Although it might not be relevant in a modern...believed that there is no legiti- mate reason to discount the utilities of future generations. Along with Bentham in 1789, he believed the utility of each

  11. Using the IPEDS Peer Analysis System to Compare Tuition Discount Rates

    Science.gov (United States)

    Duggan, Michael; Mathews, Rebecca

    2005-01-01

    Tuition discounting began in the 1970s as the practice of using university funds to augment federal, state, and private aid and scholarships. When the 1980s saw a decrease in the number of high school seniors, universities began to compete in the arena of price for the first time, sparking what has been called an "arms race" of tuition discounting…

  12. A quantitative approach to evaluating the GWP timescale through implicit discount rates

    OpenAIRE

    Sarofim, Marcus C.; Giordano, Michael R.

    2018-01-01

    The 100-year Global Warming Potential (GWP) is the primary metric used to compare the climate impacts of different greenhouse gases (GHGs). The GWP relies on radiative forcing rather than damages, assumes constant future concentrations, and integrates over a timescale of 100 years without discounting: these choices lead to a metric which is transparent and simple to calculate, but have also been criticized. In this paper, we take a quantitative approach to evaluating the choice of time-horizo...

  13. Neonatal heart rate prediction.

    Science.gov (United States)

    Abdel-Rahman, Yumna; Jeremic, Aleksander; Tan, Kenneth

    2009-01-01

    Technological advances have caused a decrease in the number of infant deaths. Pre-term infants now have a substantially increased chance of survival. One of the mechanisms that is vital to saving the lives of these infants is continuous monitoring and early diagnosis. With continuous monitoring huge amounts of data are collected with so much information embedded in them. By using statistical analysis this information can be extracted and used to aid diagnosis and to understand development. In this study we have a large dataset containing over 180 pre-term infants whose heart rates were recorded over the length of their stay in the Neonatal Intensive Care Unit (NICU). We test two types of models, empirical bayesian and autoregressive moving average. We then attempt to predict future values. The autoregressive moving average model showed better results but required more computation.

  14. Discounting and Digit Ratio: Low 2D:4D Predicts Patience for a Sample of Females

    Directory of Open Access Journals (Sweden)

    Diego Aycinena

    2018-01-01

    Full Text Available Inter-temporal trade-offs are ubiquitous in human decision making. We study the relationship between preferences over such trade-offs and the ratio of the second digit to that of the forth (2D:4D, a marker for pre-natal exposure to sex hormones. Specifically, we study whether 2D:4D affects discounting. Our sample consists of 419 female participants of a Guatemalan conditional cash transfer program who take part in an experiment. Their choices in the convex time budget (CTB experimental task allow us to make inferences regarding their patience (discounting, while controlling for present-biasedness and preference for smoothing consumption (utility curvature. We find that women with lower digit ratios tend to be more patient.

  15. Future so bright? Delay discounting and consideration of future consequences predict academic performance among college drinkers.

    Science.gov (United States)

    Acuff, Samuel F; Soltis, Kathryn E; Dennhardt, Ashley A; Borsari, Brian; Martens, Matthew P; Murphy, James G

    2017-10-01

    College student drinking is a major public health concern and can result in a range of negative consequences, from acute health risks to decreased academic performance and drop out. Harm reduction interventions have been developed to reduce problems associated with drinking but there is a need to identify specific risk/protective factors related to academic performance among college drinkers. Behavioral economics suggests that chronic alcohol misuse reflects a dysregulated behavioral process or reinforcer pathology-alcohol is overvalued and the value of prosocial rewards are sharply discounted due, in part, to their delay. This study examined delay discounting, consideration of future consequences (CFC) and protective behavioral strategies (PBS) as predictors of academic success (grade point average; GPA) and engagement (time devoted to academic activities) among 393 college drinkers (61% female). In multivariate models, PBS were associated with greater academic engagement, but were not with academic success. Lower discounting of delayed rewards and greater CFC were associated with both academic success and engagement among drinkers. Previous research suggests that future time orientation is malleable, and the current results provide support for efforts to enhance future time orientation as part of alcohol harm-reduction approaches. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  16. Me, Myself, and Money II: Relative Deprivation Predicts Disordered Gambling Severity via Delay Discounting, Especially Among Gamblers Who Have a Financially Focused Self-Concept.

    Science.gov (United States)

    Tabri, Nassim; Will Shead, N; Wohl, Michael J A

    2017-12-01

    In the current research, we examined whether the known link between relative deprivation and disordered gambling (via delay discounting; i.e., preferences for immediate smaller rewards relative to delayed larger rewards) is moderated by the extent to which gamblers have a financially focused self-concept. Specifically, we hypothesized that delay discounting would be a strong predictor of disordered gambling among those who base their self-worth on their financial success. To test this moderated-mediation model, a community sample of gamblers (N = 239) completed measures that assessed relative deprivation, delay discounting, financially focused self-concept, and disordered gambling severity. As predicted, people who felt more relative deprivation reported more severe symptoms of disordered gambling and this association was mediated by delay discounting. Importantly, this mediated relationship was moderated by the extent to which participants' self-concept was focused on financial success. Among participants whose self-concept was high in financial focus, greater delay discounting (stemming from relative deprivation) was a strong predictor of disordered gambling. Among people whose self-concept was low in financial focus, delay discounting (stemming from relative deprivation) was a weak predictor of disordered gambling. Thus, the magnitude of the indirect effect of relative deprivation on disordered gambling severity was larger among people with a more financially focused self-concept-an effect mediated by delay discounting. These findings suggest that targeting gamblers' financial focus in prevention and treatment interventions may be instrumental in curtailing the development and maintenance of disordered gambling.

  17. Hyperbolic Discounting of the Far-Distant Future

    OpenAIRE

    Anchugina, Nina; Ryan, Matthew; Slinko, Arkadii

    2017-01-01

    We prove an analogue of Weitzman's (1998) famous result that an exponential discounter who is uncertain of the appropriate exponential discount rate should discount the far-distant future using the lowest (i.e., most patient) of the possible discount rates. Our analogous result applies to a hyperbolic discounter who is uncertain about the appropriate hyperbolic discount rate. In this case, the far-distant future should be discounted using the probability-weighted harmonic mean of the possible...

  18. Effects of a Capital Investment and a Discount Rate on the Optimal Operational Duration of an HLW Repository

    International Nuclear Information System (INIS)

    Kim, Sung Ki; Lee, Min Soo; Choi, Heui Joo; Choi, Jong Won

    2008-01-01

    This study aims to estimate the effects of a capital investment and a discount rate on the optimal operational duration of an HLW repository. According to the previous researches of the KRS(Korea Reference System) for an HLW repository, the amounts of 7,068,200 C$K and 2,636.2 MEUR are necessary to construct and operate surface and underground facilities. Since these huge costs can be a burden to some national economies, a study for a cost optimization should be performed. So we aim to drive the dominant cost driver for an optimal operational duration. A longer operational duration may be needed to dispose of more spent fuels continuously from a nuclear power plant, or to attain a retrievability of an HLW repository at a depth of 500 m below the ground level in a stable plutonic rock body. In this sense, an extended operational duration for an HLW repository affects the overall disposal costs of a repository. In this paper, only the influence of a capital investment and a discount rate was estimated from the view of optimized economics. Because these effects must be significant factors to minimize the overall disposal costs based on minimizing the sum of operational costs and capital investments

  19. Test Framing Generates a Stability Bias for Predictions of Learning by Causing People to Discount their Learning Beliefs

    Science.gov (United States)

    Ariel, Robert; Hines, Jarrod C.; Hertzog, Christopher

    2014-01-01

    People estimate minimal changes in learning when making predictions of learning (POLs) for future study opportunities despite later showing increased performance and an awareness of that increase (Kornell & Bjork, 2009). This phenomenon is conceptualized as a stability bias in judgments about learning. We investigated the malleability of this effect, and whether it reflected people’s underlying beliefs about learning. We manipulated prediction framing to emphasize the role of testing vs. studying on memory and directly measured beliefs about multi-trial study effects on learning by having participants construct predicted learning curves before and after the experiment. Mean POLs were more sensitive to the number of study-test opportunities when performance was framed in terms of study benefits rather than testing benefits and POLs reflected pre-existing beliefs about learning. The stability bias is partially due to framing and reflects discounted beliefs about learning benefits rather than inherent belief in the stability of performance. PMID:25067885

  20. Optimal conservation resource allocation under variable economic and ecological time discounting rates in boreal forest.

    Science.gov (United States)

    Mazziotta, Adriano; Pouzols, Federico Montesino; Mönkkönen, Mikko; Kotiaho, Janne S; Strandman, Harri; Moilanen, Atte

    2016-09-15

    Resource allocation to multiple alternative conservation actions is a complex task. A common trade-off occurs between protection of smaller, expensive, high-quality areas versus larger, cheaper, partially degraded areas. We investigate optimal allocation into three actions in boreal forest: current standard forest management rules, setting aside of mature stands, or setting aside of clear-cuts. We first estimated how habitat availability for focal indicator species and economic returns from timber harvesting develop through time as a function of forest type and action chosen. We then developed an optimal resource allocation by accounting for budget size and habitat availability of indicator species in different forest types. We also accounted for the perspective adopted towards sustainability, modeled via temporal preference and economic and ecological time discounting. Controversially, we found that in boreal forest set-aside followed by protection of clear-cuts can become a winning cost-effective strategy when accounting for habitat requirements of multiple species, long planning horizon, and limited budget. It is particularly effective when adopting a long-term sustainability perspective, and accounting for present revenues from timber harvesting. The present analysis assesses the cost-effective conditions to allocate resources into an inexpensive conservation strategy that nevertheless has potential to produce high ecological values in the future. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Cost-effectiveness of a potential future Helicobacter pylori vaccine in the Netherlands: the impact of varying the discount rate for health.

    Science.gov (United States)

    de Vries, Robin; Klok, Rogier M; Brouwers, Jacobus R B J; Postma, Maarten J

    2009-02-05

    To estimate the cost-effectiveness of a potential Helicobacter pylori (HP) vaccine for the Dutch situation, we developed a Markov model. Several HP prevalence scenarios were assessed. Additionally, we assessed the impact of the discount rate for health on the outcomes, as this influence can be profound for vaccines. When applying the current discount rate of 1.5% for health, the expected cost-effectiveness of HP vaccination is estimated below the informal Dutch threshold of euro 20,000/LYG when the HP prevalence is assumed > or =20% in the Dutch population. In conclusion, we showed that HP vaccination could possibly be a cost-effective intervention. However, this depends to a large extend on the prevalence of HP in the population. Furthermore, we showed the large impact of the discount rate for health on the cost-effectiveness of a HP vaccination program, illustrative for other vaccination programs.

  2. Methods of economic analysis applied to fusion research: discount rate determination and the fossil fuel price effect

    Energy Technology Data Exchange (ETDEWEB)

    1978-09-25

    In current and previous efforts, ECON has provided a preliminary economic assessment of a fusion research program. Part of this effort was the demonstration of a methodology for the estimation of reactor system costs and risk and for the treatment of program alternatives as a series of steps (tests) to buy information, thereby controlling program risk and providing a sound economic rationale for properly constructed research programs. The first phase of work also identified two areas which greatly affect the overall economic evaluation of fusion research and which warranted further study in the second phase. This led to the two tasks of the second phase reported herein: (1) discount rate determination and (2) evaluation of the effect of the expectation of the introduction of fusion power on current fossil fuel prices. In the first task, various conceptual measures of the social rate of discount were reviewed and critiqued. In the second task, a benefit area that had been called out by ECON was further examined. Long-range R and D yields short-term benefits in the form of lower nonrenewable energy resource prices because the R and D provides an expectation of future competition for the remaining reserves at the time of technology availability. ECON developed a model of optimal OPEC petroleum pricing as a function of the expectation of future competing technologies. It was shown that the existence of this expectation lowers the optimal OPEC export price and that accelerated technology R and D programs should provide further price decreases. These price reductions translate into benefits to the U.S. of at least a billion dollars.

  3. Towards a healthier discount procedure.

    Science.gov (United States)

    Klock, Rogier M; Brouwer, Werner Bf; Annemans, Lieven Jp; Bos, Jasper M; Postma, Maarten J

    2005-02-01

    Most national guidelines for pharmacoeconomic research prescribe discounting, mostly of money and health against the same rate. There is much debate on whether this is adequate. Two theoretical arguments, the consistency argument of Weinstein and Stason, and the paralyzing paradox of Keeler and Cretin, are mostly responsible for the current standards. However, more recently, several authors have indicated that the basis to claim the necessity of using similar discount rates is rather weak, both practically and theoretically. In terms of finding a new theoretical basis on which to base discount rates for money and, in particular, health, Van Hout has made an important suggestion arguing that the discount rate for health could be based on the expected growth in life expectancy and the diminishing marginal utility related to such additional health. Similarly, Gravelle and Smith argue that if the value of health grows over time, discount rates that are used for costs cannot directly be applied to effects, but should be adjusted downwards.

  4. Cost-effectiveness of a potential future Helicobacter pylori vaccine in the Netherlands : The impact of varying the discount rate for health

    NARCIS (Netherlands)

    de Vries, Robin; Klok, Rogier M.; Brouwers, Jacobus R. B. J.; Postma, Maarten J.

    2009-01-01

    To estimate the cost-effectiveness of a potential Helicobacter pylori (HP) vaccine for the Dutch situation, we developed a Markov model. Several HP prevalence scenarios were assessed. Additionally, we assessed the impact of the discount rate for health on the outcomes, as this influence can be

  5. Does temporal discounting explain unhealthy behavior? A systematic review and reinforcement learning perspective

    Science.gov (United States)

    Story, Giles W.; Vlaev, Ivo; Seymour, Ben; Darzi, Ara; Dolan, Raymond J.

    2014-01-01

    The tendency to make unhealthy choices is hypothesized to be related to an individual's temporal discount rate, the theoretical rate at which they devalue delayed rewards. Furthermore, a particular form of temporal discounting, hyperbolic discounting, has been proposed to explain why unhealthy behavior can occur despite healthy intentions. We examine these two hypotheses in turn. We first systematically review studies which investigate whether discount rates can predict unhealthy behavior. These studies reveal that high discount rates for money (and in some instances food or drug rewards) are associated with several unhealthy behaviors and markers of health status, establishing discounting as a promising predictive measure. We secondly examine whether intention-incongruent unhealthy actions are consistent with hyperbolic discounting. We conclude that intention-incongruent actions are often triggered by environmental cues or changes in motivational state, whose effects are not parameterized by hyperbolic discounting. We propose a framework for understanding these state-based effects in terms of the interplay of two distinct reinforcement learning mechanisms: a “model-based” (or goal-directed) system and a “model-free” (or habitual) system. Under this framework, while discounting of delayed health may contribute to the initiation of unhealthy behavior, with repetition, many unhealthy behaviors become habitual; if health goals then change, habitual behavior can still arise in response to environmental cues. We propose that the burgeoning development of computational models of these processes will permit further identification of health decision-making phenotypes. PMID:24659960

  6. Heaven can wait. How religion modulates temporal discounting.

    Science.gov (United States)

    Paglieri, Fabio; Borghi, Anna M; Colzato, Lorenza S; Hommel, Bernhard; Scorolli, Claudia

    2013-11-01

    Evidence suggests that religious systems have specific effects on attentional and action control processes. The present study investigated whether religions also modulate choices that involve higher-order knowledge and the delay of gratification in particular. We tested Dutch Calvinists, Italian Catholics, and Atheists from both countries/cultures using an intertemporal choice task where participants could choose between a small immediate and a larger delayed monetary reward. Based on the Calvinist theory of predestination and the Catholic concept of a cycle of sin-confession-expiation, we predicted a reduced delay tolerance, i.e., higher discount rate, for Italian Catholics than for Dutch Calvinists, and intermediate rates for the two atheist groups. Analyses of discount rates support our hypotheses. We also found a magnitude effect on temporal discounting and faster responses for large than for small rewards across religions and countries/cultures. We conclude that temporal discounting is specifically modulated by religious upbringing rather than by generic cultural differences.

  7. Social Discounting under Risk.

    Science.gov (United States)

    Jin, Jia; Pei, Guanxiong; Ma, Qingguo

    2017-01-01

    As a measure of how prosocial behavior depends on social distance, social discounting is defined as the decrease in generosity between the decision maker and the recipient as the social distance increases. While risk is a ubiquitous part of modern life, there is limited research on the relationship between risk and prosocial behavior. In the present experiment, we empirically test whether risk has an influence on social discounting. We use the choice titration procedure to examine this effect. Our data show that independent of risk, participants are less eager to forego money and exhibit more selfishness toward a specific person when the social distance increases; these findings are reflected in the hyperbolic model. Interestingly, risk influences the shape of the social discounting function, which is reflected in the notable different discount rates. Individuals who make decisions under risk yield a smaller discount rate than those who make decisions without risk, i.e., under risk subjects reduce less their generosity as a function of the social distance. Furthermore, this distinct type of generosity occurs typically among individuals with 10-distance recipients but not with the closest- and furthest-social-distance recipients.

  8. Emotional arousal and discount rate in intertemporal choice are reference dependent.

    Science.gov (United States)

    Lempert, Karolina M; Glimcher, Paul W; Phelps, Elizabeth A

    2015-04-01

    Many decisions involve weighing immediate gratification against future consequences. In such intertemporal choices, people often choose smaller, immediate rewards over larger delayed rewards. It has been proposed that emotional responses to immediate rewards lead us to choose them at our long-term expense. Here we utilize an objective measure of emotional arousal-pupil dilation-to examine the role of emotion in these decisions. We show that emotional arousal responses, as well as choices, in intertemporal choice tasks are reference-dependent and reflect the decision-maker's recent history of offers. Arousal increases when less predictable rewards are better than expected, whether those rewards are immediate or delayed. Furthermore, when immediate rewards are less predictable than delayed rewards, participants tend to be patient. When delayed rewards are less predictable, immediate rewards are preferred. Our findings suggest that we can encourage people to be more patient by changing the context in which intertemporal choices are made. (c) 2015 APA, all rights reserved).

  9. Individual Differences in Discount Rate Are Associated With Demand for Self-Administered Cocaine, But Not Sucrose

    OpenAIRE

    Koffarnus, Mikhail N.; Woods, James H.

    2011-01-01

    Substance abusers, including cocaine abusers, discount delayed rewards to a greater extent than do matched controls. In the current experiment, individual differences in discounting of delayed rewards in rats (choice of one immediate over three delayed sucrose pellets) were assessed for associations with demand for either sucrose pellets or an i.v. dose of 0.1 mg/kg/infusion cocaine. Twenty-four male Sprague Dawley rats were split into three groups based on sensitivity to delay to reinforceme...

  10. Anodal Stimulation of the Left DLPFC Increases IGT Scores and Decreases Delay Discounting Rate in Healthy Males

    Directory of Open Access Journals (Sweden)

    Qinghua He

    2016-09-01

    Full Text Available Previous correlational imaging studies have implicated the dorsolateral prefrontal cortex (DLPFC in decision making. Using High-Definition Transcranial Direct Current Stimulation (HD-tDCS, the present study directly investigated the causal role of the DLPFC in performing the Iowa Gambling Task (IGT and the Inter-Temporal Choice (ITC task. Three experiments were conducted: Exp. 1 (N = 41 to study the left DLPFC, Exp. 2 (N = 49 to study the right DLPFC, and Exp. 3 (N = 20, a subset of those in Exp. 1 to switch the experimental and control conditions. All participants were healthy male college students. For Exps. 1 and 2, participants were randomly assigned to either the HD- tDCS or the sham stimulation condition. For Exp. 3, participants were assigned to the condition they were not in during Exp. 1. Results showed that HD-tDCS over the left DLPFC increased IGT score, decreased the recency parameter in IGT, and lowered delay discounting rate (k in the ITC task. We discussed the potential roles of impulse control and time perception in mediating the effect of tDCS stimulation of left DLPFC on decision making. Our results have clinical implications for the treatment of disorders involving poor decision-making, such as addictions.

  11. Economic comparison of long-term nuclear fuel cycle management scenarios: The influence of the discount rate

    International Nuclear Information System (INIS)

    Le Dars, Aude; Loaec, Christine

    2007-01-01

    This article presents some main economic results obtained by the CEA in the DERECO project, which aimed to evaluate the global cost of contrasted and long-term nuclear fuel cycle scenarios. The scenarios have been studied for the period 2000-2150 in the French context. They all assume a sustainable nuclear development. These scenarios must not be considered as forecasts and do not reflect any industrial strategy. The article focuses on the comparison of five scenarios including the Generation IV fast reactors and their associated fuel cycles. Common trends as well as specific features can be identified. The article describes the scenarios with the replacement of the nuclear power and the associated fuel cycle. It details the main technical and economic assumptions common to all the scenarios, and exposes some main key results, concerning the flows and inventories as well as concerning economic evaluation. Economic results are given in a comparative manner due to the level of uncertainties at this time horizon. The key economic elements described in the article deal with the sensitivity of the results to the choice of the discount rate

  12. This time it is different! Or not? : Discounting past data when predicting the future

    NARCIS (Netherlands)

    Ph.H.B.F. Franses (Philip Hans); E. Janssens (Eva)

    2017-01-01

    textabstractWe employ a simple method based on logistic weighted least squares to diagnose which past data are less or more useful for predicting the future course of a variable. A simulation experiment shows its merits. An illustration for monthly industrial production series for 17 countries

  13. Antipredator defenses predict diversification rates

    Science.gov (United States)

    Arbuckle, Kevin; Speed, Michael P.

    2015-01-01

    The “escape-and-radiate” hypothesis predicts that antipredator defenses facilitate adaptive radiations by enabling escape from constraints of predation, diversified habitat use, and subsequently speciation. Animals have evolved diverse strategies to reduce the direct costs of predation, including cryptic coloration and behavior, chemical defenses, mimicry, and advertisement of unprofitability (conspicuous warning coloration). Whereas the survival consequences of these alternative defenses for individuals are well-studied, little attention has been given to the macroevolutionary consequences of alternative forms of defense. Here we show, using amphibians as the first, to our knowledge, large-scale empirical test in animals, that there are important macroevolutionary consequences of alternative defenses. However, the escape-and-radiate hypothesis does not adequately describe them, due to its exclusive focus on speciation. We examined how rates of speciation and extinction vary across defensive traits throughout amphibians. Lineages that use chemical defenses show higher rates of speciation as predicted by escape-and-radiate but also show higher rates of extinction compared with those without chemical defense. The effect of chemical defense is a net reduction in diversification compared with lineages without chemical defense. In contrast, acquisition of conspicuous coloration (often used as warning signals or in mimicry) is associated with heightened speciation rates but unchanged extinction rates. We conclude that predictions based on the escape-and-radiate hypothesis must incorporate the effect of traits on both speciation and extinction, which is rarely considered in such studies. Our results also suggest that knowledge of defensive traits could have a bearing on the predictability of extinction, perhaps especially important in globally threatened taxa such as amphibians. PMID:26483488

  14. Time-discounting and tobacco smoking: a systematic review and network analysis.

    Science.gov (United States)

    Barlow, Pepita; McKee, Martin; Reeves, Aaron; Galea, Gauden; Stuckler, David

    2017-06-01

    Tobacco smoking harms health, so why do people smoke and fail to quit? An explanation originating in behavioural economics suggests a role for time-discounting, which describes how the value of a reward, such as better health, decreases with delay to its receipt. A large number of studies test the relationship of time-discounting with tobacco outcomes but the temporal pattern of this relationship and its variation according to measurement methods remain unclear. We review the association between time-discounting and smoking across (i) the life course, from initiation to cessation, and (ii) diverse discount measures. We identified 69 relevant studies in Web of Science and PubMed. We synthesized findings across methodologies and evaluated discount measures, study quality and cross-disciplinary fertilization. In 44 out of 54 studies, smokers more greatly discounted the future than non-smokers and, in longitudinal studies, higher discounting predicted future smoking. Smokers with lower time-discount rates achieved higher quit rates. Findings were consistent across studies measuring discount rates using hypothetical monetary or cigarette reward scenarios. The methodological quality of the majority of studies was rated as 'moderate' and co-citation analysis revealed an isolation of economics journals and a dearth of studies in public health. There is moderate yet consistent evidence that high time-discounting is a risk factor for smoking and unsuccessful cessation. Policy scenarios assuming a flat rate of population discounting may inadequately capture smokers' perceptions of costs and benefits. © The Author 2016; Published by Oxford University Press on behalf of the International Epidemiological Association

  15. Essays on Discounting Behavior and Gambling Behavior

    OpenAIRE

    Jessen, Lasse J.

    2016-01-01

    This thesis consists of three independent chapters on the elicitation of individual discount rates and on the estimation of gambling prevalence in Denmark. The first chapter, “Discount Rate Sensitivity to Background Consumption and Consumption Smoothing,” studies the sensitivity of individual discount rates with respect to background consumption and consumption smoothing. I use simulated choice data from standard decision tasks in time preference experiments and show that indiv...

  16. Discounting in economics and climate change

    International Nuclear Information System (INIS)

    Nordhaus, W.D.

    1997-01-01

    This paper examines the complexity of the issues surrounding the discounting issue as applied to the economics of climatic change. It is assumed that living standards will continue to improve, and that future generations will be more able to resource environmental improvements than our own. Measures to counter climate change now may have a deleterious effect on economic growth. Approaches to this situation include: lowering the discount rate; differential discounting; climate targeting; and emissions or concentrations limitations. Policies that focus directly on reducing pollutants are likely to have fewer deleterious economic effects than those that manipulate the discount rate on goods. 3 refs., 2 figs

  17. Essays on Discounting Behavior and Gambling Behavior

    DEFF Research Database (Denmark)

    Jessen, Lasse J.

    This thesis consists of three independent chapters on the elicitation of individual discount rates and on the estimation of gambling prevalence in Denmark. The first chapter, “Discount Rate Sensitivity to Background Consumption and Consumption Smoothing,” studies the sensitivity of individual...

  18. Can Exchange Rates Be Predicted?

    OpenAIRE

    Siriwutiset, Trin

    2007-01-01

    Foreign exchange rates produce significant impacts on both the macroeconomic and microeconomic scale. Countries� government and multinational companies have been seeking ways to stabilize the exchange rates for a few decades. However, there is no perfect consensus on methods to control and stabilize the exchange rates. In fact, there are several occasions in history where turbulence movements caused crisis in the economies. There are several factors that are identified by economis...

  19. Discounting medical malpractice claim reserves for self-insured hospitals.

    Science.gov (United States)

    Frese, Richard; Kitchen, Patrick

    2011-01-01

    The hospital CFO often works with the hospital's actuary and external auditor to calculate the reserves recorded in financial statements. Hospital management, usually the CFO, needs to decide the discount rate that is most appropriate. A formal policy addressing the rationale for discounting and the rationale for selecting the discount rate can be helpful to the CFO, actuary, and external auditor.

  20. Delay Discounting as an Index of Sustainable Behavior: Devaluation of Future Air Quality and Implications for Public Health.

    Science.gov (United States)

    Berry, Meredith S; Nickerson, Norma P; Odum, Amy L

    2017-09-01

    Poor air quality and resulting annual deaths represent significant public health concerns. Recently, rapid delay discounting (the devaluation of future outcomes) of air quality has been considered a potential barrier for engaging in long term, sustainable behaviors that might help to reduce emissions (e.g., reducing private car use, societal support for clean air initiatives). Delay discounting has been shown to be predictive of real world behavior outside of laboratory settings, and therefore may offer an important framework beyond traditional variables thought to measure sustainable behavior such as importance of an environmental issue, or environmental attitudes/values, although more research is needed in this area. We examined relations between discounting of air quality, respiratory health, and monetary gains and losses. We also examined, relations between discounting and self-reported importance of air quality and respiratory health, and nature relatedness. Results showed rapid delay discounting of all outcomes across the time frames assessed, and significant positive correlations between delay discounting of air quality, respiratory health, and monetary outcomes. Steeper discounting of monetary outcomes relative to air quality and respiratory health outcomes was observed in the context of gains; however, no differences in discounting were observed across losses of monetary, air quality, and respiratory health. Replicating the sign effect, monetary outcomes were discounted more steeply than monetary losses. Importance of air quality, respiratory health and nature relatedness were significantly and positively correlated with one another, but not with degree of delay discounting of any outcome, demonstrating the need for more comprehensive measures that predict pro-environmental behaviors that might benefit individuals and public health over time. These results add to our understanding of decision-making, and demonstrate alarming rates of delay discounting of

  1. Predicting Performance Ratings Using Motivational Antecedents

    National Research Council Canada - National Science Library

    Zazania, Michelle

    1998-01-01

    This research examined the role of motivation in predicting peer and trainer ratings of student performance and contrasted the relative importance of various antecedents for peer and trainer ratings...

  2. Rating prediction using textual reviews

    Science.gov (United States)

    NithyaKalyani, A.; Ushasukhanya, S.; Nagamalleswari, TYJ; Girija, S.

    2018-04-01

    Information today is present in the form of opinions. Two & a half quintillion bytes are exchanged today in Internet everyday and a large amount consists of people’s speculation and reflection over an issue. It is the need of the hour to be able to mine this information that is presented to us. Sentimental analysis refers to mining of this raw information to make sense. The discipline of opinion mining has seen a lot of encouragement in the past few years augmented by involvement of social media like Instagram, Facebook, and twitter. The hidden message in this web of information is useful in several fields such as marketing, political polls, product review, forecast market movement, Identifying detractor and promoter. In this endeavor, we introduced sentiment rating system for a particular text or paragraph to determine the opinions polarity. Firstly we resolve the searching problem, tokenization, classification, and reliable content identification. Secondly we extract probability for given text or paragraph for both positive & negative sentiment value using naive bayes classifier. At last we use sentiment dictionary (SD), sentiment degree dictionary (SDD) and negation dictionary (ND) for more accuracy. Later we blend all above mentioned factor into given formula to find the rating for the review.

  3. Future Discounting in Congo Basin Hunter-Gatherers Declines with Socio-Economic Transitions.

    Directory of Open Access Journals (Sweden)

    Gul Deniz Salali

    Full Text Available Humans have a tendency to discount the future; that is we value small, short-term rewards over larger, long-term rewards. The degree of future discounting, however, changes in response to socio-ecological factors. Here, we study Mbendjele BaYaka hunter-gatherers of northern Congo and their farmer neighbours to investigate adaptations in inter-temporal preferences in humans. We argue that in immediate-return systems, where food storage is absent and egalitarianism is enforced through levelling mechanisms, future discounting is an adaptive strategy to prevent wealth accumulation and the emergence of hierarchies. This ensures food sharing and allows for survival in unpredictable environments where there is risk of an energy shortfall. On the other hand, when food storage is made possible by the emergence of agriculture or as seen in some delayed-return hunter-gatherer populations, wealth accumulation, hierarchies and lower discount rates become the adaptive strategy. Therefore, individuals in immediate-return, egalitarian societies will discount the future more than those in non-egalitarian, delayed-return societies. Consistent with the predictions we found that market integration and socio-economic transitions decrease the future discounting in Mbendjele hunter-gatherers. Our measures of socio-economic differences marked this transition in hunter-gatherers living in a logging town. The degree of future-discounting was the same between more market-integrated hunter-gatherers and their farmer neighbours.

  4. Discounted Duration Calculus

    DEFF Research Database (Denmark)

    Ody, Heinrich; Fränzle, Martin; Hansen, Michael Reichhardt

    2016-01-01

    To formally reason about the temporal quality of systems discounting was introduced to CTL and LTL. However, these logic are discrete and they cannot express duration properties. In this work we introduce discounting for a variant of Duration Calculus. We prove decidability of model checking...... for a useful fragment of discounted Duration Calculus formulas on timed automata under mild assumptions. Further, we provide an extensive example to show the usefulness of the fragment....

  5. The effects of working memory load and attention refocusing on delay discounting rates in alcohol use disorder with comorbid antisocial personality disorder.

    Science.gov (United States)

    Gunn, Rachel L; Gerst, Kyle R; Lake, Allison J; Finn, Peter R

    2018-02-01

    Executive working memory capacity (eWMC) is central to adaptive decision-making. Research has revealed reduced eWMC and higher rates of impulsive decision making in individuals with alcohol use disorders (AUDs: DSM-IV Alcohol Dependence of Alcohol Abuse) and antisocial psychopathology (AP). Recent work has shown that placing a load on working memory (WM) further increases impulsive decision making on the delay discounting (DD) task in those with AUDs and AP. The current study examined the effects of an attention refocusing manipulation to offset the effects of this WM-load on DD rates in control subjects, those with AUDs without AP, and AUDs with AP (AUD-AP). Results revealed that 1) the AUD-AP group had higher DD rates (i.e., more impulsive decision-making) than the AUD group, followed by controls, and 2) attention refocusing after a load is placed on WM was associated with lower DD rates compared to the load without refocusing in both AUD groups, but not controls. Results suggest that refocusing attention after a cognitive load may be an effective cognitive strategy for reducing the impulsivity-enhancing effects of cognitive load on decision making in individuals with AUDs and AP. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Discounting in Time

    DEFF Research Database (Denmark)

    Fahrenberg, Uli; Larsen, Kim Guldstrand

    2009-01-01

    This paper deals with the issue of discounting in weighted timed transition systems. Discounting provides a way to model optimal-cost problems for infinite runs and has applications in optimal scheduling and other areas. We show that when postulating a certain natural additivity property for the ......This paper deals with the issue of discounting in weighted timed transition systems. Discounting provides a way to model optimal-cost problems for infinite runs and has applications in optimal scheduling and other areas. We show that when postulating a certain natural additivity property...

  7. Discounting Behaviour and the Magnitude Effect

    DEFF Research Database (Denmark)

    Andersen, Steffen; Harrison, Glenn W.; Lau, Morten Igel

    2013-01-01

    We evaluate the claim that individuals exhibit a magnitude effect in their discounting behaviour, where higher discount rates are inferred from choices made with lower principals, all else being equal. If the magnitude effect is quantitatively significant, it is not appropriate to use one discount...... rate that is independent of the scale of the project for cost–benefit analysis and capital budgeting. Using data from a field experiment in Denmark, we find statistically significant evidence of a magnitude effect that is much smaller than is claimed. This evidence surfaces only if one controls...

  8. Temporal Discounting Is Associated with an Increased Risk of Mortality among Community-Based Older Persons without Dementia.

    Directory of Open Access Journals (Sweden)

    Patricia A Boyle

    Full Text Available Temporal discounting is an important determinant of many health and financial outcomes, but we are not aware of studies that have examined the association of temporal discounting with mortality.Participants were 406 older persons without dementia from the Rush Memory and Aging Project, a longitudinal cohort study of aging. Temporal discounting was measured using standard preference elicitation questions. Individual discount rates were estimated using a well-established hyperbolic function and used to predict the risk of mortality during up to 5 years of follow-up.The mean estimate of discounting was 0.45 (SD = 0.33, range: 0.08-0.90, with higher scores indicating a greater propensity to prefer smaller immediate rewards over larger but delayed ones. During up to 5 years of follow-up (mean = 3.6 years, 62 (15% of 406 persons died. In a proportional hazards model adjusted for age, sex, and education, temporal discounting was associated with an increased risk of mortality (HR = 1.103, 95% CI 1.024, 1.190, p = 0.010. Thus, a person with the highest discount rate (score = 0.90 was about twice more likely to die over the study period compared to a person with the lowest discount rate (score = 0.08. Further, the association of discounting with mortality persisted after adjustment for the level of global cognitive function, the burden of vascular risk factors and diseases, and an indicator of psychological well being (i.e., purpose in life.Temporal discounting is associated with an increased risk of mortality in old age after accounting for global cognitive function and indicators of physical and mental health.

  9. Discounting in the economic evaluation of health care interventions.

    Science.gov (United States)

    Krahn, M; Gafni, A

    1993-05-01

    Do economic theories that underlie discounting have specific implications for program evaluation in health? In this study, both the contemporary practice and the theoretical foundations of discounting are reviewed. The social discount rate controversy is considered, and the two major concepts (i.e., opportunity cost and time preference) involved in the formulation of a social discount rate are outlined. Also described are the arguments for discounting proposed by thinkers in non-economic disciplines. Finally, the implications of choosing a discount rate for evaluation of individual health care programs are considered. It is argued that the conventional practice of discounting all health care programs at a rate of 5% may not consistently reflect societal or individual preference. Specific recommendations arising from this paper are: 1) given the considerable disagreement at the theoretical level as to the appropriate social discount rate, analysts should be specific about what theoretical approach underlies their choice of rate, especially when the analytic result is sensitive to the discount rate; 2) the discount rate chosen should be appropriate for the perspective of the analysis (social vs. individual vs. institutional, etc.); 3) when appropriate, measures should be taken to avoid double discounting, because some health related outcome measures already incorporate individuals' time preference; and 4) it is suggested that the political process may serve as the appropriate means of reflecting social values in the choice of a discount rate. In addition, the authors argue that a consensus conference approach, with political participation, offers a flexible, pragmatic, and explicit way of synthesizing the empirical, normative, and ethical considerations that underlie choice of a discount rate.

  10. Values in Time Discounting.

    Science.gov (United States)

    Heilmann, Conrad

    2017-10-01

    Controversies about time discounting loom large in decisions about climate change. Prominently, a particularly controversial debate about time discounting in climate change decision-making has been conducted within climate economics, between the authors of Stern et al. (Stern review on the economics of climate change, 2006) and their critics (most prominently Dasgupta in Comments on the Stern review's economics of climate change, 2006; Tol in Energy Environ 17(6):977-981, 2006; Weitzman in J Econ Lit XLV:703-724, 2007; Nordhaus in J Econ Lit XLV:686-702, 2007). The article examines the role of values in this debate. Firstly, it is shown that time discounting is a case in which values are key because it is at heart an ethical problem. Secondly, it is argued that time discounting in climate economics is a case of economists making frequent and routine references to ethical values and indeed conduct ethical debates with each other. Thirdly, it is argued that there is evidence for deep and pervasive entanglement between facts and values in the prevalent methodologies for time discounting. Finally, it is argued that this means that economists have given up the 'value-free ideal' concerning time discounting, and discussed how the current methodology of time discounting in economics can be improved.

  11. The economics of climate change and the theory of discounting

    International Nuclear Information System (INIS)

    Philibert, C.

    1999-01-01

    This paper confronts the theory of discounting with climate change economics. Standard discounting would give long-term damages a very low present value. On the other hand, low discount rates would imply more sacrifices for present generations, although future generations may be richer. And using multiple rates would lead to economic inefficiencies. The paper first shows that arguments favouring a low or zero discount rate in general are weak, even from an ethical point of view. It goes on by considering different arguments in favour of discount rates decreasing over time, and by recalling the argument that non-reproducible environmental assets should be given a value growing over time. Through the example of climate change, it finally shows that the latter argument not only implies that the costs of damages associated to climate change should not be underestimated, but also reinforce the legitimacy of using decreasing discount rates. (author)

  12. Sleep deprivation alters effort discounting but not delay discounting of monetary rewards.

    Science.gov (United States)

    Libedinsky, Camilo; Massar, Stijn A A; Ling, Aiqing; Chee, Weiyan; Huettel, Scott A; Chee, Michael W L

    2013-06-01

    To determine whether sleep deprivation would affect the discounting of delayed rewards, of rewards entailing the expense of effort, or both. We measured rates of two types of reward discounting under conditions of rested wakefulness (RW) and sleep deprivation (SD). Delay discounting was defined as the willingness to accept smaller monetary rewards sooner rather than larger monetary rewards later. Effort discounting was defined as the willingness to accept smaller rewards that require less effort to obtain (e.g., typing a small number of letter strings backward) over larger but more effortful rewards (e.g., typing more letter strings to receive the reward). The first two experiments used a crossover design in which one session was conducted after a normal night of sleep (RW), and the other after a night without sleep (SD). The first experiment evaluated only temporal discounting whereas the second evaluated temporal and effort discounting. In the second experiment, the discounting tasks were repeatedly administered prior to the state comparisons to minimize the effects of order and/or repeated testing. In a third experiment, participants were studied only once in a between-subject evaluation of discounting across states. The study took place in a research laboratory. Seventy-seven healthy young adult participants: 20 in Experiment 1, 27 in Experiment 2, and 30 in Experiment 3. N/A. Sleep deprivation elicited increased effort discounting but did not affect delay discounting. The dissociable effects of sleep deprivation on two forms of discounting behavior suggest that they may have differing underlying neural mechanisms.

  13. Survey of time preference, delay discounting models

    Directory of Open Access Journals (Sweden)

    John R. Doyle

    2013-03-01

    Full Text Available The paper surveys over twenty models of delay discounting (also known as temporal discounting, time preference, time discounting, that psychologists and economists have put forward to explain the way people actually trade off time and money. Using little more than the basic algebra of powers and logarithms, I show how the models are derived, what assumptions they are based upon, and how different models relate to each other. Rather than concentrate only on discount functions themselves, I show how discount functions may be manipulated to isolate rate parameters for each model. This approach, consistently applied, helps focus attention on the three main components in any discounting model: subjectively perceived money; subjectively perceived time; and how these elements are combined. We group models by the number of parameters that have to be estimated, which means our exposition follows a trajectory of increasing complexity to the models. However, as the story unfolds it becomes clear that most models fall into a smaller number of families. We also show how new models may be constructed by combining elements of different models. The surveyed models are: Exponential; Hyperbolic; Arithmetic; Hyperboloid (Green and Myerson, Rachlin; Loewenstein and Prelec Generalized Hyperboloid; quasi-Hyperbolic (also known as beta-delta discounting; Benhabib et al's fixed cost; Benhabib et al's Exponential / Hyperbolic / quasi-Hyperbolic; Read's discounting fractions; Roelofsma's exponential time; Scholten and Read's discounting-by-intervals (DBI; Ebert and Prelec's constant sensitivity (CS; Bleichrodt et al.'s constant absolute decreasing impatience (CADI; Bleichrodt et al.'s constant relative decreasing impatience (CRDI; Green, Myerson, and Macaux's hyperboloid over intervals models; Killeen's additive utility; size-sensitive additive utility; Yi, Landes, and Bickel's memory trace models; McClure et al.'s two exponentials; and Scholten and Read's trade

  14. Open access discount information

    International Development Research Centre (IDRC) Digital Library (Canada)

    Lauren Doyle

    Wiley Interdisciplinary Reviews: Climate Change. Wiley offers OA in: Gold: ... International Journal of Health Services. Journal of ... Camridge University Press offers waivers and discounts based on: 1) Authors of ... based on the World Bank list.

  15. Discounting risks in the far future

    International Nuclear Information System (INIS)

    Lind, Niels

    2007-01-01

    Risks to life and health in the future must be discounted in quantitative risk analysis. Yet, risks in the distant future become trivialized if any reasonable constant interest rate is used. Our responsibility toward future generations rules out such drastic discounting. A solution to this problem is proposed here, resting on the ethical principle that our duty with respect to saving lives is the same to all generations, whether in the near or far future. It is shown that when a choice between prospects involving different risks has a financing horizon T, then ordinary principles of discounting apply up to this time T, while no further discounting is justifiable after T. The principle implies that risk events beyond the financing horizon should be valued as if they occurred at the financing horizon

  16. On the Dividend Strategies with Non-Exponential Discounting

    OpenAIRE

    Zhao, Qian; Wei, Jiaqin; Wang, Rongming

    2013-01-01

    In this paper, we study the dividend strategies for a shareholder with non-constant discount rate in a diffusion risk model. We assume that the dividends can only be paid at a bounded rate and restrict ourselves to the Markov strategies. This is a time inconsistent control problem. The extended HJB equation is given and the verification theorem is proved for a general discount function. Considering the pseudo-exponential discount functions (Type I and Type II), we get the equilibrium dividend...

  17. The Vivid Present: Visualization Abilities Are Associated with Steep Discounting of Future Rewards.

    Science.gov (United States)

    Parthasarathi, Trishala; McConnell, Mairead H; Luery, Jeffrey; Kable, Joseph W

    2017-01-01

    Humans and other animals discount the value of future rewards, a phenomenon known as delay discounting. Individuals vary widely in the extent to which they discount future rewards, and these tendencies have been associated with important life outcomes. Recent studies have demonstrated that imagining the future reduces subsequent discounting behavior, but no research to date has examined whether a similar principle applies at the trait level, and whether training visualization changes discounting. The current study examined if individual differences in visualization abilities are linked to individual differences in discounting and whether practicing visualization can change discounting behaviors in a lasting way. Participants ( n = 48) completed the Vividness of Visual Imagery Questionnaire (VVIQ) and delay discounting task and then underwent a 4-week intervention consisting of visualization training (intervention) or relaxation training (control). Contrary to our hypotheses, participants who reported greater visualization abilities (lower scores) on the VVIQ were higher discounters. To further examine this relationship, an additional 106 participants completed the VVIQ and delay discounting task. In the total sample ( n = 154), there was a significant negative correlation between VVIQ scores and discount rates, showing that individuals who are better visualizers are also higher discounters. Consistent with this relationship but again to our surprise, visualization training tended, albeit weakly, to increase discount rates, and those whose VVIQ decreased the most were those whose discount rates increased the most. These results suggest a novel association between visualization abilities and delay discounting.

  18. Observed and Normative Discount Functions in Addiction and other Diseases.

    Science.gov (United States)

    Cruz Rambaud, Salvador; Muñoz Torrecillas, María J; Takahashi, Taiki

    2017-01-01

    The aim of this paper is to find a suitable discount function able to describe the progression of a certain addiction or disease under treatment as a discounting process. In effect, a certain indicator related to a disease decays over time in a manner which is mathematically similar to the way in which discounting has been modeled. We analyze the discount functions observed in experiments which study addictive and other problematic behaviors as well as some alternative hyperbola-like discount functions in order to fit the patience exhibited by the subject after receiving the treatment. Additionally, it has been experimentally found that people with addiction display high rates of discount (impatience) and preference reversals (dynamic inconsistency). This excessive discounting must be correctly modeled by a suitable discount function, otherwise, it can become a trans-disease process underlying addiction and other disorders. The (generalized) exponentiated hyperbolic discount function is proposed to describe the progression of a disease with respect to the treatment, since it maintains the property of inconsistency by exhibiting a decreasing discount rate after an initial period in which the opposite occurs.

  19. Accounting conventions for discounting in the optimisation of protection

    International Nuclear Information System (INIS)

    Fleishman, A.B.

    1983-01-01

    Some of the implications which arise from the use of accounting conventions in the cost benefit framework for optimization of radiation protection are briefly examined. Some accounting techniques which appear not to discount future detriment costs do so, in fact, at a hidden fixed rate; others give a free choice over whether to discount and at what rate. (U.K.)

  20. Explicit information reduces discounting behavior in monkeys

    Directory of Open Access Journals (Sweden)

    John ePearson

    2010-12-01

    Full Text Available Animals are notoriously impulsive in common laboratory experiments, preferring smaller, sooner rewards to larger, delayed rewards even when this reduces average reward rates. By contrast, the same animals often engage in natural behaviors that require extreme patience, such as food caching, stalking prey, and traveling long distances to high quality food sites. One possible explanation for this discrepancy is that standard laboratory delay discounting tasks artificially inflate impulsivity by subverting animals’ common learning strategies. To test this idea, we examined choices made by rhesus macaques in two variants of a standard delay discounting task. In the conventional variant, post-reward delays were uncued and adjusted to render total trial length constant; in the second, all delays were cued explicitly. We found that measured discounting was significantly reduced in the cued task, with discount rates well below those reported in studies using the standard uncued design. When monkeys had complete information, their decisions were more consistent with a strategy of reward rate maximization. These results indicate that monkeys, and perhaps other animals, are more patient than is normally assumed, and that laboratory measures of delay discounting may overstate impulsivity.

  1. Value of the future: Discounting in random environments

    Science.gov (United States)

    Farmer, J. Doyne; Geanakoplos, John; Masoliver, Jaume; Montero, Miquel; Perelló, Josep

    2015-05-01

    We analyze how to value future costs and benefits when they must be discounted relative to the present. We introduce the subject for the nonspecialist and take into account the randomness of the economic evolution by studying the discount function of three widely used processes for the dynamics of interest rates: Ornstein-Uhlenbeck, Feller, and log-normal. Besides obtaining exact expressions for the discount function and simple asymptotic approximations, we show that historical average interest rates overestimate long-run discount rates and that this effect can be large. In other words, long-run discount rates should be substantially less than the average rate observed in the past, otherwise any cost-benefit calculation would be biased in favor of the present and against interventions that may protect the future.

  2. Predicting extinction rates in stochastic epidemic models

    International Nuclear Information System (INIS)

    Schwartz, Ira B; Billings, Lora; Dykman, Mark; Landsman, Alexandra

    2009-01-01

    We investigate the stochastic extinction processes in a class of epidemic models. Motivated by the process of natural disease extinction in epidemics, we examine the rate of extinction as a function of disease spread. We show that the effective entropic barrier for extinction in a susceptible–infected–susceptible epidemic model displays scaling with the distance to the bifurcation point, with an unusual critical exponent. We make a direct comparison between predictions and numerical simulations. We also consider the effect of non-Gaussian vaccine schedules, and show numerically how the extinction process may be enhanced when the vaccine schedules are Poisson distributed

  3. Prediction of waste glass melt rates

    International Nuclear Information System (INIS)

    Lee, L.

    1987-01-01

    Under contract to the Department of Energy, the Du Pont Company has begun construction of a Defense Waste Processing Facility to immobilize radioactive wastes now stored as liquids at the Department of Energy's Savannah River Plant. The immobilization process solidifies waste sludge by vitrification into a leach-resistant borosilicate glass. Development of this process has been the responsibility of the Savannah River Laboratory. As part of the development, a simple model was developed to predict the melt rates for the waste glass melter. This model is based on an energy balance for the cold cap and gives very good agreement with melt rate data obtained from experimental campaigns in smaller scale waste glass melters

  4. Discounting the future: influence of the economic model.

    Science.gov (United States)

    West, R R

    1996-06-01

    To consider the effect of the economic discount rate on health care policy and the rationale for discounting the collective future of society generally. A review of the concept of discounting the future vis à vis the present from the points of view of individuals (who pass on) and of societies (that continue) and reconsideration of the application of discounting to typical public health scenarios. A public health service, within a basically stable society, which can reasonably anticipate a nearly certain future. Discounting necessarily overvalues the "here and now" compared with the future. While applications of discount rates, typical of those employed in health economic studies in recent years, may seem rational in health care programmes directed at middle aged employed people, they do not for the young and the elderly, important recipients of health care. The consequences of discounting do not accord with the aims and objectives of public health. The "time preferences" of transient individuals within a stable society do not provide a rational basis for time preference of a stable society collectively. Discounting inevitably encourages "short termism" and hence biases public policy decision making. The neoclassical theory that gave rise to the concept of discounting requires revision.

  5. Benefit assessment in Germany: implications for price discounts.

    Science.gov (United States)

    Theidel, Ulrike; von der Schulenburg, J-Matthias Graf

    2016-12-01

    The AMNOG regulation, introduced in 2011 in Germany, changed the game for new drugs. Now, the industry is required to submit a dossier to the GBA (the central decision body in the German sickness fund system) to show additional benefit. After granting the magnitude of the additional benefit by the GBA, the manufacturer is entitled to negotiate the reimbursement price with the GKV-SV (National Association of Statutory Health Insurance Funds). The reimbursement price is defined as a discount on the drug price at launch. As the price or discount negotiations between the manufacturers and the GKV-SV takes place behind closed doors, the factors influencing the results of the negotiation are not known. The aim of this evaluation is to identify factors influencing the results of the AMNOG price negotiation process. The analysis was based on a dataset containing detailed information on all assessments until the end of 2015. A descriptive analysis was followed by an econometric analysis of various potential factors (benefit rating, size of target population, deviating from appropriate comparative therapy and incorporation of HRQoL-data). Until December 2015, manufacturers and the GKV-SV finalized 96 negotiations in 193 therapeutic areas, based on assessment conducted by the GBA. The GBA has granted an additional benefit to 100/193 drug innovations. Negotiated discount was significantly higher for those drugs without additional benefit (p = 0.030) and non-orphan drugs (p = 0.015). Smaller population size, no deviation from recommended appropriate comparative therapy and the incorporation of HRQoL-data were associated with a lower discount on the price at launch. However, neither a uni- nor the multivariate linear regression showed enough power to predict the final discount. Although the AMNOG regulation implemented binding and strict rules for the benefit assessment itself, the outcome of the discount negotiations are still unpredictable. Obviously, negotiation

  6. On the Relation between Discounting of Climate Change and Edgeworth-Pareto Substitutability

    NARCIS (Netherlands)

    Kögel, M.T.

    2009-01-01

    To justify substantial carbon emission reductions, recent literature on cost-benefit analysis of climate change suggests discounting environmental quality at a lower discount rate than the standard consumption discount rate. Recent literature also shows that a theoretical foundation for such a lower

  7. Predicting Agency Rating Migrations with Spread Implied Ratings

    OpenAIRE

    Jianming Kou; Dr Simone Varotto

    2005-01-01

    Investors traditionally rely on credit ratings to price debt instruments. However, rating agencies are known to be prudent in their approach to rating revisions, which results in delayed ratings adjustments to mutating credit conditions. For a large set of eurobonds we derive credit spread implied ratings and compare them with the ratings issued by rating agencies. Our results indicate that spread implied ratings often anticipate future movement of agency ratings and hence could help track cr...

  8. Shopping in discount stores

    DEFF Research Database (Denmark)

    Zielke, Stephan

    2014-01-01

    quarters of intentions to shop in discount stores. Value perception has the strongest total effect, which is partly mediated by enjoyment, shame and guilt. Attributions influence the shopping intention indirectly via value perception and emotions. The inferior quality attribution has the strongest total......This paper analyzes the impact of price-related attributions, emotions and value perception on the intention to shop at grocery discounters in an integrated framework. Moderating effects of price consciousness are also analyzed. The results show that the proposed model explains almost three...... effect, followed by the efficiency of the business model attribution. The unfairness to stakeholders and the tricks in price communication attribution mostly influence the shopping intention for less price-conscious customers....

  9. An Examination of The Transdiagnostic Role of Delay Discounting in Psychological Inflexibility and Mental Health Problems

    OpenAIRE

    Levin, Michael; Haeger, Jack; Ong, Clarissa W.; Twohig, Michael P.

    2018-01-01

    Delay discounting is a basic behavioral process that has been found to predict addictive behaviors, and more recently, other mental health problems. Acceptance and Commitment Therapy (ACT), is a transdiagnostic treatment that appears to alter delay discounting, possibly through reducing psychological inflexibility. The current study sought to further bridge research on delay discounting and ACT by examining the relation of delay discounting to a broad range of selfreported mental health probl...

  10. Discounting in the evaluation of the cost-effectiveness of a vaccination programme: A critical review.

    Science.gov (United States)

    Jit, Mark; Mibei, Walter

    2015-07-31

    Discounting future costs and health benefits usually has a large effect on results of cost-effectiveness evaluations of vaccination because of delays between the initial expenditure in the programme and the health benefits from averting disease. Most guidelines currently recommend discounting both costs and health effects at a positive, constant, common rate back to a common point in time. A review of 84 published economic evaluations of vaccines found that most of them apply these recommendations. However, both technical and normative arguments have been presented for discounting health at a different rate to consumption (differential discounting), discounting at a rate that changes over time (non-constant discounting), discounting intra-generational and inter-generational effects at a different rate (two-stage discounting), and discounting the health gains from an intervention to a different discount year from the time of intervention (delayed discounting). These considerations are particularly acute for vaccines, because their effects can occur in a different generation from the one paying for them, and because the time of vaccination, of infection aversion, and of disease aversion usually differ. Using differential, two-stage or delayed discounting in model-based cost-effectiveness evaluations of vaccination raises technical challenges, but mechanisms have been proposed to overcome them. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  11. Network Effects Versus Strategic Discounting

    DEFF Research Database (Denmark)

    Zucchini, Leon; Claussen, Jörg; Trüg, Moritiz

    . Alternatively, research on strategic discounting suggests small operators use on-net discounts to advertise with low on-net prices. We test the relative strength of these effects using data on tariff setting in German mobile telecommunications between 2001 and 2009. We find that large operators are more likely......Mobile telecommunication operators routinely charge subscribers lower prices for calls on their own network than for calls to other networks (on-net discounts). Studies on tariff-mediated network effects suggest this is due to large operators using on-net discounts to damage smaller rivals...

  12. The Contrast Effect in Temporal and Probabilistic Discounting

    Science.gov (United States)

    Chen, Cheng; He, Guibing

    2016-01-01

    In this information age, messages related to time, and uncertainty surround us. At the same time, our daily lives are filled with decisions accompanied by temporal delay or uncertainty. Will such information influence our temporal and probabilistic discounting? The authors address this question from the perspectives of decision by sampling (DbS) theory and psychological distance theory. Studies 1 and 2 investigated the effect of contextual messages on temporal discounting and probabilistic discounting, respectively. The results indicated that participants who memorized messages about long-term and low-probability events rated delay or uncertainty as mentally closer and exhibited a less degree of value discounting than those who memorized messages regarding short-term and high-probability events. In addition, a sense of distance from present or reality mediated the effect of contextual messages on value discounting. The implications of the current findings for theory and applications are discussed. PMID:27014122

  13. Delay discounting as a function of intrinsic/extrinsic religiousness, religious fundamentalism, and regular church attendance.

    Science.gov (United States)

    Weatherly, Jeffrey N; Plumm, Karyn M

    2012-01-01

    Delay discounting occurs when the subjective value of an outcome decreases because its delivery is delayed. Previous research has suggested that the rate at which some, but not all, outcomes are discounted varies as a function of regular church attendance. In the present study, 509 participants completed measures of intrinsic religiousness, extrinsic religiousness, religious fundamentalism, and whether they regularly attended church services. They then completed a delay-discounting task involving five outcomes. Although religiousness was not a significant predictor of discounting for all outcomes, participants scoring high in intrinsic religiousness tended to display less delay discounting than participants scoring low. Likewise, participants scoring high in religious fundamentalism tended to display more delay discounting than participants scoring low. These results partially replicate previous ones in showing that the process of discounting may vary as a function of religiousness. The results also provide some direction for those interested in altering how individuals discount.

  14. Impacts of religious semantic priming on an intertemporal discounting task: Response time effects and neural correlates.

    Science.gov (United States)

    Morgan, Jonathan; Clark, Dustin; Tripodis, Yorghos; Halloran, Christopher S; Minsky, April; Wildman, Wesley J; Durso, Raymon; McNamara, Patrick

    2016-08-01

    The purpose of this study is to test the hypothesis that religious primes would influence intertemporal discounting behaviors in neurotypical older adults, but not in participants with Parkinson's disease (PD). Furthermore, we predicted that this priming effect would be related to functional connectivity within neural networks mediating religious cognition, decision-making, reward valuing, and prospection processes. Contrary to past research with young adults, we found a significant positive relationship between religiosity and discounting rates. Religious semantic primes did not reliably shift individual discounting rates. But religious controls did respond more quickly to intertemporal decisions under the religious priming condition than the neutral condition, compared to response time differences among the participants with PD. Differences in response time were significantly associated with functional connectivity between the nucleus accumbens and various regions, including the left anterior cingulate cortex and Brodmann areas 10 and 46 in the right dorsolateral prefrontal cortex. These results suggest that religious primes influence discounting behavior via dopaminergic meso-limbic and right dorsolateral prefrontal supporting cognitive valuation and prospection processes. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Discounting of quantity surveying fees in South Africa

    African Journals Online (AJOL)

    by clients have forced Quantity Surveying firms into competition with ... Furthermore, 43% of consulting engineering firms were discounting their fees at a rate of .... Quantity. Surveying services are also offered in the fields of dispute resolution,.

  16. Climate policy under sustainable discounted utilitarianism

    Energy Technology Data Exchange (ETDEWEB)

    Dietz, Simon [London School of Economics and Political Science (LSE) (United Kingdom); Asheim, Geir B. [Oslo Univ. (Norway). Dept. of Economics

    2011-08-15

    Empirical evaluation of policies to mitigate climate change has been largely confined to the application of discounted utilitarianism (DU). DU is controversial, both due to the conditions through which it is justified and due to its consequences for climate policies, where the discounting of future utility gains from present abatement efforts makes it harder for such measures to justify their present costs. In this paper, we propose sustainable discounted utilitarianism (SDU) as an alternative principle for evaluation of climate policy. Unlike undiscounted utilitarianism, which always assigns zero relative weight to present utility, SDU is an axiomatically based criterion, which departs from DU by assigning zero weight to present utility if and only if the present is better off than the future. Using the DICE integrated assessment model to run risk analysis, we show that it is possible for the future to be worse off than the present along a 'business as usual' development path. Consequently SDU and DU differ, and willingness to pay for emissions reductions is (sometimes significantly) higher under SDU than under DU. Under SDU, stringent schedules of emissions reductions increase social welfare, even for a relatively high utility discount rate. (orig.)

  17. 5 CFR 1315.7 - Discounts.

    Science.gov (United States)

    2010-01-01

    ... acceptance has occurred. Agencies are encouraged to include discount terms in a contract to give agencies... web site at http://www.fms.treas.gov/prompt/index.html. (b) Discounts taken after the discount date...

  18. Delayed discounting of pain with and without monetary reward

    Directory of Open Access Journals (Sweden)

    Kicman Paweł

    2017-12-01

    Full Text Available We investigated the effect of monetary rewards on the rate of pain discounting. Our aim, also, was to understand the effect of previous painful dental experiences on the rate of discounting pain. Two groups (N = 148 completed a discounting task. In the first group, delayed pain was weaker than immediate pain, and in the second group delayed pain was stronger than immediate pain. Two conditions were studied: pain was either accompanied by a monetary reward or not. We found that people preferred immediate pain when it was weaker than delayed pain; however, when delayed pain was stronger than immediate pain, there was no clear preference. In both groups the preference for immediate pain was higher when pain was accompanied by a monetary reward. Previous painful experiences were not related to the rate of discounting. It was concluded that the preference for delayed pain depends on the intensity of pain, and it can be modified by rewards that accompany pain.

  19. Discounted cost model for condition-based maintenance optimization

    International Nuclear Information System (INIS)

    Weide, J.A.M. van der; Pandey, M.D.; Noortwijk, J.M. van

    2010-01-01

    This paper presents methods to evaluate the reliability and optimize the maintenance of engineering systems that are damaged by shocks or transients arriving randomly in time and overall degradation is modeled as a cumulative stochastic point process. The paper presents a conceptually clear and comprehensive derivation of formulas for computing the discounted cost associated with a maintenance policy combining both condition-based and age-based criteria for preventive maintenance. The proposed discounted cost model provides a more realistic basis for optimizing the maintenance policies than those based on the asymptotic, non-discounted cost rate criterion.

  20. Steeper discounting of delayed rewards in schizophrenia but not first-degree relatives.

    Science.gov (United States)

    Yu, Linda Q; Lee, Sangil; Katchmar, Natalie; Satterthwaite, Theodore D; Kable, Joseph W; Wolf, Daniel H

    2017-06-01

    Excessive discounting of future rewards has been related to a variety of risky behaviors and adverse clinical conditions. Prior work examining delay discounting in schizophrenia suggests an elevated discount rate. However, it remains uncertain whether this reflects the disease process itself or an underlying genetic vulnerability, whether it is selective for delay discounting or reflects pervasive changes in decision-making, and whether it is driven by specific clinical dimensions such as cognitive impairment. Here we investigated delay discounting, as well as loss aversion and risk aversion, in three groups: schizophrenia (SZ), unaffected first-degree family members (FM), and controls without a family history of psychosis (NC). SZ had elevated discounting, without changes in loss aversion or risk aversion. Contrary to expectations, the FM group did not show an intermediate phenotype in discounting. Higher discount rates correlated with lower cognitive performance on verbal reasoning, but this did not explain elevated discount rates in SZ. Group differences were driven primarily by the non-smoking majority of the sample. This study provides further evidence for elevated discounting in schizophrenia, and demonstrates that steeper discounting is not necessarily associated with familial risk, cannot be wholly accounted for by cognitive deficits, and is not attributable to smoking-related impulsivity. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

  1. Time discounting and protected-area priorities.

    Science.gov (United States)

    Armsworth, Paul R

    2018-05-08

    Should conservation organizations focus on protecting habitats that are at imminent risk of being converted but are expensive or more remote areas that are less immediately threatened but where a large amount of land can be set aside? Variants of this trade-off commonly arise in spatial planning. We examined this trade-off using models of land use change near a deforestation frontier. The optimal choice of where to protect was determined by how decisions taken today accounted for ecological benefits and economic costs of conservation actions that would occur sometime in the future. We used an ecological and economic discount rate to weight these benefits and costs. A large economic discount rate favored protecting more remote areas, whereas a large, positive ecological discount rate favored protecting habitat near the current deforestation frontier. We also showed how the decision over where to protect was impacted by the influence that economic factors had in determining landowners' decisions, the rate of technological change and ecological heterogeneity of the landscape. How benefits and costs through time are accounted for warrants careful consideration when specifying conservation objectives. It may provide a niche axis along which conservation organizations differentiate themselves when competing for donor funding or other support. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  2. Effects of episodic future thinking on discounting: Personalized age-progressed pictures improve risky long-term health decisions.

    Science.gov (United States)

    Kaplan, Brent A; Reed, Derek D; Jarmolowicz, David P

    2016-03-01

    Many everyday choices are associated with both delayed and probabilistic outcomes. The temporal attention hypothesis suggests that individuals' decision making can be improved by focusing attention on temporally distal events and implies that environmental manipulations that bring temporally distal outcomes into focus may alter an individual's degree of discounting. One such manipulation, episodic future thinking, has shown to lower discount rates; however, several questions remain about the applicability of episodic future thinking to domains other than delay discounting. The present experiments examine the effects of a modified episodic-future-thinking procedure in which participants viewed age-progressed computer-generated images of themselves and answered questions related to their future, on probability discounting in the context of both a delayed health gain and loss. Results indicate that modified episodic future thinking effectively altered individuals' degree of discounting in the predicted directions and demonstrate the applicability of episodic future thinking to decision making of socially significant outcomes. © 2015 Society for the Experimental Analysis of Behavior.

  3. A Job with a Future? Delay Discounting, Magnitude Effects, and Domain Independence of Utility for Career Decisions.

    Science.gov (United States)

    Schoenfelder, Thomas E.; Hantula, Donald A.

    2003-01-01

    Seniors (n=20) assessed two job offers with differences in domain (salary/tasks), delay (career-long earnings), and magnitude (initial salary offer). Contrary to discounted utility theory, choices reflected nonconstant discount rates for future salary/tasks (delay effect), lower discount rates for salary/preferred tasks (magnitude effect), and a…

  4. Twitter Predicts Citation Rates of Ecological Research.

    Science.gov (United States)

    Peoples, Brandon K; Midway, Stephen R; Sackett, Dana; Lynch, Abigail; Cooney, Patrick B

    2016-01-01

    The relationship between traditional metrics of research impact (e.g., number of citations) and alternative metrics (altmetrics) such as Twitter activity are of great interest, but remain imprecisely quantified. We used generalized linear mixed modeling to estimate the relative effects of Twitter activity, journal impact factor, and time since publication on Web of Science citation rates of 1,599 primary research articles from 20 ecology journals published from 2012-2014. We found a strong positive relationship between Twitter activity (i.e., the number of unique tweets about an article) and number of citations. Twitter activity was a more important predictor of citation rates than 5-year journal impact factor. Moreover, Twitter activity was not driven by journal impact factor; the 'highest-impact' journals were not necessarily the most discussed online. The effect of Twitter activity was only about a fifth as strong as time since publication; accounting for this confounding factor was critical for estimating the true effects of Twitter use. Articles in impactful journals can become heavily cited, but articles in journals with lower impact factors can generate considerable Twitter activity and also become heavily cited. Authors may benefit from establishing a strong social media presence, but should not expect research to become highly cited solely through social media promotion. Our research demonstrates that altmetrics and traditional metrics can be closely related, but not identical. We suggest that both altmetrics and traditional citation rates can be useful metrics of research impact.

  5. Twitter predicts citation rates of ecological research

    Science.gov (United States)

    Peoples, Brandon K.; Midway, Stephen R.; Sackett, Dana K.; Lynch, Abigail; Cooney, Patrick B.

    2016-01-01

    The relationship between traditional metrics of research impact (e.g., number of citations) and alternative metrics (altmetrics) such as Twitter activity are of great interest, but remain imprecisely quantified. We used generalized linear mixed modeling to estimate the relative effects of Twitter activity, journal impact factor, and time since publication on Web of Science citation rates of 1,599 primary research articles from 20 ecology journals published from 2012–2014. We found a strong positive relationship between Twitter activity (i.e., the number of unique tweets about an article) and number of citations. Twitter activity was a more important predictor of citation rates than 5-year journal impact factor. Moreover, Twitter activity was not driven by journal impact factor; the ‘highest-impact’ journals were not necessarily the most discussed online. The effect of Twitter activity was only about a fifth as strong as time since publication; accounting for this confounding factor was critical for estimating the true effects of Twitter use. Articles in impactful journals can become heavily cited, but articles in journals with lower impact factors can generate considerable Twitter activity and also become heavily cited. Authors may benefit from establishing a strong social media presence, but should not expect research to become highly cited solely through social media promotion. Our research demonstrates that altmetrics and traditional metrics can be closely related, but not identical. We suggest that both altmetrics and traditional citation rates can be useful metrics of research impact.

  6. Cognitive decline is associated with risk aversion and temporal discounting in older adults without dementia.

    Directory of Open Access Journals (Sweden)

    Bryan D James

    Full Text Available Risk aversion and temporal discounting are preferences that are strongly linked to sub-optimal financial and health decision making ability. Prior studies have shown they differ by age and cognitive ability, but it remains unclear whether differences are due to age-related cognitive decline or lower cognitive abilities over the life span. We tested the hypothesis that cognitive decline is associated with higher risk aversion and temporal discounting in 455 older persons without dementia from the Memory and Aging Project, a longitudinal cohort study of aging in Chicago. All underwent repeated annual cognitive evaluations using a detailed battery including 19 tests. Risk aversion was measured using standard behavioral economics questions: participants were asked to choose between a certain monetary payment versus a gamble in which they could gain more or nothing; potential gamble gains varied across questions. Temporal discounting: participants were asked to choose between an immediate, smaller payment and a delayed, larger one; two sets of questions addressed small and large stakes based on payment amount. Regression analyses were used to examine whether prior rate of cognitive decline predicted level of risk aversion and temporal discounting, controlling for age, sex, and education. Over an average of 5.5 (SD=2.9 years, cognition declined at an average of 0.016 units per year (SD=0.03. More rapid cognitive decline predicted higher levels of risk aversion (p=0.002 and temporal discounting (small stakes: p=0.01, high stakes: p=0.006. Further, associations between cognitive decline and risk aversion (p=0.015 and large stakes temporal discounting (p=0.026 persisted in analyses restricted to persons without any cognitive impairment (i.e., no dementia or mild cognitive impairment; the association of cognitive decline and small stakes temporal discounting was no longer statistically significant (p=0.078. These findings are consistent with the

  7. Cognitive decline is associated with risk aversion and temporal discounting in older adults without dementia.

    Science.gov (United States)

    James, Bryan D; Boyle, Patricia A; Yu, Lei; Han, S Duke; Bennett, David A

    2015-01-01

    Risk aversion and temporal discounting are preferences that are strongly linked to sub-optimal financial and health decision making ability. Prior studies have shown they differ by age and cognitive ability, but it remains unclear whether differences are due to age-related cognitive decline or lower cognitive abilities over the life span. We tested the hypothesis that cognitive decline is associated with higher risk aversion and temporal discounting in 455 older persons without dementia from the Memory and Aging Project, a longitudinal cohort study of aging in Chicago. All underwent repeated annual cognitive evaluations using a detailed battery including 19 tests. Risk aversion was measured using standard behavioral economics questions: participants were asked to choose between a certain monetary payment versus a gamble in which they could gain more or nothing; potential gamble gains varied across questions. Temporal discounting: participants were asked to choose between an immediate, smaller payment and a delayed, larger one; two sets of questions addressed small and large stakes based on payment amount. Regression analyses were used to examine whether prior rate of cognitive decline predicted level of risk aversion and temporal discounting, controlling for age, sex, and education. Over an average of 5.5 (SD=2.9) years, cognition declined at an average of 0.016 units per year (SD=0.03). More rapid cognitive decline predicted higher levels of risk aversion (p=0.002) and temporal discounting (small stakes: p=0.01, high stakes: p=0.006). Further, associations between cognitive decline and risk aversion (p=0.015) and large stakes temporal discounting (p=0.026) persisted in analyses restricted to persons without any cognitive impairment (i.e., no dementia or mild cognitive impairment); the association of cognitive decline and small stakes temporal discounting was no longer statistically significant (p=0.078). These findings are consistent with the hypothesis that

  8. Can slide positivity rates predict malaria transmission?

    Directory of Open Access Journals (Sweden)

    Bi Yan

    2012-04-01

    Full Text Available Abstract Background Malaria is a significant threat to population health in the border areas of Yunnan Province, China. How to accurately measure malaria transmission is an important issue. This study aimed to examine the role of slide positivity rates (SPR in malaria transmission in Mengla County, Yunnan Province, China. Methods Data on annual malaria cases, SPR and socio-economic factors for the period of 1993 to 2008 were obtained from the Center for Disease Control and Prevention (CDC and the Bureau of Statistics, Mengla, China. Multiple linear regression models were conducted to evaluate the relationship between socio-ecologic factors and malaria incidence. Results The results show that SPR was significantly positively associated with the malaria incidence rates. The SPR (β = 1.244, p = 0.000 alone and combination (SPR, β = 1.326, p  Conclusion SPR is a strong predictor of malaria transmission, and can be used to improve the planning and implementation of malaria elimination programmes in Mengla and other similar locations. SPR might also be a useful indicator of malaria early warning systems in China.

  9. Delay Discounting of Losses in Alcohol Use Disorders and Antisocial Psychopathology: Effects of a Working Memory Load.

    Science.gov (United States)

    Gerst, Kyle R; Gunn, Rachel L; Finn, Peter R

    2017-10-01

    Alcohol use disorders (AUDs) are associated with increased discounting of delayed rewards and reduced executive working memory (eWM) capacity. This association is amplified when comorbid with antisocial psychopathology (AP). Furthermore, recent studies suggest that reduced WM capacity is associated with disinhibited decisions reflected by increased impulsive decision making on the delay discounting of rewards task. While discounting of delayed rewards is well studied, the discounting of delayed losses has received significantly less experimental attention. The current study investigated (i) the rate of discounting of delayed losses in individuals with AUD only (n = 61), AUD with comorbid AP (n = 79) and healthy controls (n = 64); (ii) the relationship between eWM capacity and discounting of delayed losses; and (iii) the effect of a WM load on discounting of delayed losses. Discounting performance was assessed using a computerized discounting of delayed losses task. Results showed that the AUD-only and AUD-AP groups had higher rates of discounting of delayed losses and lower eWM capacity compared to the control groups. Lower individual eWM capacity was associated with increased discounting of delayed losses. However, WM load did not increase discounting rates overall. These results support the hypothesis that greater discounting of delayed losses is associated with AUD and comorbid AP problems and lower individual eWM capacity. Copyright © 2017 by the Research Society on Alcoholism.

  10. Synchronisation of customers’ orders using discounts

    DEFF Research Database (Denmark)

    Buhayenko, Viktoryia; van Eikenhorst, Erik

    2016-01-01

    Conventionally, price discounts are offered to enhance demand, for example to get rid of excess inventory. This paper, however, studies the possibility of using discounts in situations when total demand is non-sensitive to changes in prices. By introducing a discount in some periods, the supplier...... the supplier's profit a modification of the heuristic which differs in the discount approximation used is developed....

  11. Assessing delay discounting in mice

    OpenAIRE

    Mitchell, Suzanne H.

    2014-01-01

    Delay discounting (also intertemporal choice or impulsive choice) is the process by which delayed outcomes, such as delayed food delivery, are valued less than the same outcomes delivered immediately or with a shorter delay. This process is of interest because many psychopathologies, including substance dependence, pathological gambling, attention deficit hyperactivity disorder and conduct disorder, are characterized by heightened levels of delay discounting. Some of these disorders are herit...

  12. PREDICTING EVAPORATION RATES AND TIMES FOR SPILLS OF CHEMICAL MIXTURES

    Science.gov (United States)

    Spreadsheet and short-cut methods have been developed for predicting evaporation rates and evaporation times for spills (and constrained baths) of chemical mixtures. Steady-state and time-varying predictions of evaporation rates can be made for six-component mixtures, includ...

  13. Is there time discounting for risk premium?

    Science.gov (United States)

    Shavit, Tal; Rosenboim, Mosi

    2015-03-01

    Individuals with a higher subjective discount rate concentrate more on the present and delay is more significant for them. However, when a risky asset is delayed, not only is the outcome delayed but also the risk. In this paper, we suggest a new, two-stage experimental method with real monetary incentives that allows us to distinguish between the effect of the risk and the effect of the time when pricing a risky asset. We show that when individuals have greater preference for the present, their risk aversion for a risky asset realized in the future decreases. We argue that the effect of the risk for future asset is lower for individuals with higher time preference because they discount not only the outcome but also the risks. © Society for the Experimental Analysis of Behavior.

  14. Beyond discounting: possible experimental models of impulse control.

    Science.gov (United States)

    Monterosso, J; Ainslie, G

    1999-10-01

    Animal studies of impulsivity have typically used one of three models: a delay of reward procedure, a differential reinforcement for low rate responding (DRL) procedure, or an autoshaping procedure. In each of these paradigms, we argue, measurement of impulsivity is implicitly or explicitly equated with the effect delay has on the value of reward. The steepness by which delay diminishes value (the temporal discount function) is treated as an index of impulsivity. In order to provide a better analog of human impulsivity, this model needs to be expanded to include the converse of impulsivity - self-control. Through mechanisms such as committing to long range interests before the onset of temptation, or through bundling individual choices into classes of choices that are made at once, human decision-making can often look far less myopic than single trial experiments predict. For people, impulsive behavior may be more often the result of the breakdown of self-control mechanisms than of steep discount functions. Existing animal models of self-control are discussed, and future directions are suggested for psychopharmacological research.

  15. Positive autobiographical memory retrieval reduces temporal discounting.

    Science.gov (United States)

    Lempert, Karolina M; Speer, Megan E; Delgado, Mauricio R; Phelps, Elizabeth A

    2017-10-01

    People generally prefer rewards sooner rather than later. This phenomenon, temporal discounting, underlies many societal problems, including addiction and obesity. One way to reduce temporal discounting is to imagine positive future experiences. Since there is overlap in the neural circuitry associated with imagining future experiences and remembering past events, here we investigate whether recalling positive memories can also promote more patient choice. We found that participants were more patient after retrieving positive autobiographical memories, but not when they recalled negative memories. Moreover, individuals were more impulsive after imagining novel positive scenes that were not related to their memories, showing that positive imagery alone does not drive this effect. Activity in the striatum and temporo parietal junction during memory retrieval predicted more patient choice, suggesting that to the extent that memory recall is rewarding and involves perspective-taking, it influences decision-making. Furthermore, representational similarity in the ventromedial prefrontal cortex between memory recall and decision phases correlated with the behavioral effect across participants. Thus, we have identified a novel manipulation for reducing temporal discounting-remembering the positive past-and have begun to characterize the psychological and neural mechanisms behind it. © The Author (2017). Published by Oxford University Press.

  16. INFLUENCE OF DISCOUNT PRICE ANNOUNCEMENTS ON CONSUMER’S BEHAVIOR

    Directory of Open Access Journals (Sweden)

    Giuliana Isabella

    2012-10-01

    Full Text Available The theoretical framework that underpins this research study is based on the Prospect Theory formulated by Kahneman and Tversky, and Thaler´s Mental Accounting Theory. The research aims to evaluate the consumers’ behavior when different patterns of discount are offered (in percentage and absolute value and for larger and smaller discounts. Two experiments were conducted to explore these patterns of behavior and the results that were obtained supported the view that the framing effect was a common occurrence. The patterns of choice of individuals in a sample were found to be different due to changes in the ways discounts were offered. This can be explained by the various ways of presenting discount rates that had an impact on the influence of purchase intentions, recommendations and quality perception.

  17. Delay and probability discounting of sexual and monetary outcomes in individuals with cocaine use disorders and matched controls.

    Science.gov (United States)

    Johnson, Matthew W; Johnson, Patrick S; Herrmann, Evan S; Sweeney, Mary M

    2015-01-01

    Individuals with cocaine use disorders are disproportionately affected by HIV/AIDS, partly due to higher rates of unprotected sex. Recent research suggests delay discounting of condom use is a factor in sexual HIV risk. Delay discounting is a behavioral economic concept describing how delaying an event reduces that event's value or impact on behavior. Probability discounting is a related concept describing how the uncertainty of an event decreases its impact on behavior. Individuals with cocaine use disorders (n = 23) and matched non-cocaine-using controls (n = 24) were compared in decision-making tasks involving hypothetical outcomes: delay discounting of condom-protected sex (Sexual Delay Discounting Task), delay discounting of money, the effect of sexually transmitted infection (STI) risk on likelihood of condom use (Sexual Probability Discounting Task), and probability discounting of money. The Cocaine group discounted delayed condom-protected sex (i.e., were more likely to have unprotected sex vs. wait for a condom) significantly more than controls in two of four Sexual Delay Discounting Task partner conditions. The Cocaine group also discounted delayed money (i.e., preferred smaller immediate amounts over larger delayed amounts) significantly more than controls. In the Sexual Probability Discounting Task, both groups showed sensitivity to STI risk, however the groups did not differ. The Cocaine group did not consistently discount probabilistic money more or less than controls. Steeper discounting of delayed, but not probabilistic, sexual outcomes may contribute to greater rates of sexual HIV risk among individuals with cocaine use disorders. Probability discounting of sexual outcomes may contribute to risk of unprotected sex in both groups. Correlations showed sexual and monetary results were unrelated, for both delay and probability discounting. The results highlight the importance of studying specific behavioral processes (e.g., delay and probability

  18. Delay and probability discounting of sexual and monetary outcomes in individuals with cocaine use disorders and matched controls.

    Directory of Open Access Journals (Sweden)

    Matthew W Johnson

    Full Text Available Individuals with cocaine use disorders are disproportionately affected by HIV/AIDS, partly due to higher rates of unprotected sex. Recent research suggests delay discounting of condom use is a factor in sexual HIV risk. Delay discounting is a behavioral economic concept describing how delaying an event reduces that event's value or impact on behavior. Probability discounting is a related concept describing how the uncertainty of an event decreases its impact on behavior. Individuals with cocaine use disorders (n = 23 and matched non-cocaine-using controls (n = 24 were compared in decision-making tasks involving hypothetical outcomes: delay discounting of condom-protected sex (Sexual Delay Discounting Task, delay discounting of money, the effect of sexually transmitted infection (STI risk on likelihood of condom use (Sexual Probability Discounting Task, and probability discounting of money. The Cocaine group discounted delayed condom-protected sex (i.e., were more likely to have unprotected sex vs. wait for a condom significantly more than controls in two of four Sexual Delay Discounting Task partner conditions. The Cocaine group also discounted delayed money (i.e., preferred smaller immediate amounts over larger delayed amounts significantly more than controls. In the Sexual Probability Discounting Task, both groups showed sensitivity to STI risk, however the groups did not differ. The Cocaine group did not consistently discount probabilistic money more or less than controls. Steeper discounting of delayed, but not probabilistic, sexual outcomes may contribute to greater rates of sexual HIV risk among individuals with cocaine use disorders. Probability discounting of sexual outcomes may contribute to risk of unprotected sex in both groups. Correlations showed sexual and monetary results were unrelated, for both delay and probability discounting. The results highlight the importance of studying specific behavioral processes (e.g., delay and

  19. Prediction of pipeline corrosion rate based on grey Markov models

    International Nuclear Information System (INIS)

    Chen Yonghong; Zhang Dafa; Peng Guichu; Wang Yuemin

    2009-01-01

    Based on the model that combined by grey model and Markov model, the prediction of corrosion rate of nuclear power pipeline was studied. Works were done to improve the grey model, and the optimization unbiased grey model was obtained. This new model was used to predict the tendency of corrosion rate, and the Markov model was used to predict the residual errors. In order to improve the prediction precision, rolling operation method was used in these prediction processes. The results indicate that the improvement to the grey model is effective and the prediction precision of the new model combined by the optimization unbiased grey model and Markov model is better, and the use of rolling operation method may improve the prediction precision further. (authors)

  20. I want it and I want it now: using a temporal discounting paradigm to examine predictors of consumer impulsivity.

    Science.gov (United States)

    Dittmar, Helga; Bond, Rod

    2010-11-01

    This paper proposes a new model of consumer impulsivity, using type of good, a person's endorsement of materialistic values, and identity deficits as predictors. Traditional decision making and psychological accounts see impulsive behaviour as a general overweighing of short-term gratification (I want that dress now) relative to longer-term concerns, irrespective of consumer good. Our proposal is that consumers' impulsivity (a) differs according to type of good and (b) is linked systematically to a combination of materialistic values and high identity deficits. Beginning with Study 1, three experiments, using a temporal discounting paradigm, show consistently that discount rates are higher for goods that are seen as highly expressive of identity (e.g., clothes) than goods not expressive of identity (e.g., basic body care products). For materialistic consumers, identity deficits predict discount rates for identity-expressive goods (Study 2), and discount rates change for materialistic individuals when their identity deficits are made salient (Study 3). These findings support a conceptualization of consumer impulsivity as identity-seeking behaviour.

  1. Testing the Reliability of Delay Discounting of Ten Commodities Using the Fill-in-the-Blank Method

    Science.gov (United States)

    Weatherly, Jeffrey N.; Derenne, Adam; Terrell, Heather K.

    2011-01-01

    Several measures of delay discounting have been shown to be reliable over periods of up to 3 months. In the present study, 115 participants completed a fill-in-the-blank (FITB) delay-discounting task on sets of 5 different commodities, 12 weeks apart. Results showed that discounting rates were not well described by a hyperbolic function but were…

  2. Changing delay discounting in the light of the competing neurobehavioral decision systems theory: a review.

    Science.gov (United States)

    Koffarnus, Mikhail N; Jarmolowicz, David P; Mueller, E Terry; Bickel, Warren K

    2013-01-01

    Excessively devaluing delayed reinforcers co-occurs with a wide variety of clinical conditions such as drug dependence, obesity, and excessive gambling. If excessive delay discounting is a trans-disease process that underlies the choice behavior leading to these and other negative health conditions, efforts to change an individual's discount rate are arguably important. Although discount rate is often regarded as a relatively stable trait, descriptions of interventions and environmental manipulations that successfully alter discount rate have begun to appear in the literature. In this review, we compare published examples of procedures that change discount rate and classify them into categories of procedures, including therapeutic interventions, direct manipulation of the executive decision-making system, framing effects, physiological state effects, and acute drug effects. These changes in discount rate are interpreted from the perspective of the competing neurobehavioral decision systems theory, which describes a combination of neurological and behavioral processes that account for delay discounting. We also suggest future directions that researchers could take to identify the mechanistic processes that allow for changes in discount rate and to test whether the competing neurobehavioral decision systems view of delay discounting is correct. © Society for the Experimental Analysis of Behavior.

  3. Evolutionary rate variation and RNA secondary structure prediction

    DEFF Research Database (Denmark)

    Knudsen, B.; Andersen, E.S.; Damgaard, C.

    2004-01-01

    Predicting RNA secondary structure using evolutionary history can be carried out by using an alignment of related RNA sequences with conserved structure. Accurately determining evolutionary substitution rates for base pairs and single stranded nucleotides is a concern for methods based on this type...... by applying rates derived from tRNA and rRNA to the prediction of the much more rapidly evolving 5'-region of HIV-1. We find that the HIV-1 prediction is in agreement with experimental data, even though the relative evolutionary rate between A and G is significantly increased, both in stem and loop regions...

  4. Discounting of qualitatively different delayed health outcomes in current and never smokers

    Science.gov (United States)

    Friedel, Jonathan E.; DeHart, William B.; Frye, Charles C. J.; Rung, Jillian M.; Odum, Amy L.

    2016-01-01

    In delay discounting, temporally remote outcomes have less value. Cigarette smoking is associated with steeper discounting of money and consumable outcomes. It is presently unclear whether smokers discount health outcomes more than non-smokers. We sought to establish the generality of steep discounting for different types of health outcomes in cigarette smokers. Seventy participants (38 smokers and 32 non-smokers) completed four hypothetical outcome delay-discounting tasks: a gain of $500, a loss of $500, a temporary boost in health, and temporary cure from a debilitating disease. Participants reported the duration of each health outcome that would be equivalent to $500; these durations were then used in the respective discounting tasks. Delays ranged from 1 week to 25 years. Smokers’ indifference points for monetary gains, boosts in health, and temporary cures were lower than indifference points from non-smokers. Indifference points of one outcome were correlated with indifference points of other outcomes. Smokers demonstrate steeper discounting across a range of delayed outcomes. How a person discounts one outcome predicts how they will discount other outcomes. These two findings support our assertion that delay discounting is in part a trait. PMID:26691848

  5. The neural basis of cultural differences in delay discounting.

    Science.gov (United States)

    Kim, Bokyung; Sung, Young Shin; McClure, Samuel M

    2012-03-05

    People generally prefer to receive rewarding outcomes sooner rather than later. Such preferences result from delay discounting, or the process by which outcomes are devalued for the expected delay until their receipt. We investigated cultural differences in delay discounting by contrasting behaviour and brain activity in separate cohorts of Western (American) and Eastern (Korean) subjects. Consistent with previous reports, we find a dramatic difference in discounting behaviour, with Americans displaying much greater present bias and elevated discount rates. Recent neuroimaging findings suggest that differences in discounting may arise from differential involvement of either brain reward areas or regions in the prefrontal and parietal cortices associated with cognitive control. We find that the ventral striatum is more greatly recruited in Americans relative to Koreans when discounting future rewards, but there is no difference in prefrontal or parietal activity. This suggests that a cultural difference in emotional responsivity underlies the observed behavioural effect. We discuss the implications of this research for strategic interrelations between Easterners and Westerners.

  6. Predicting rates of inbreeding in populations undergoing selection

    NARCIS (Netherlands)

    Woolliams, J.A.; Bijma, P.

    2000-01-01

    Tractable forms of predicting rates of inbreeding (F) in selected populations with general indices, nonrandom mating, and overlapping generations were developed, with the principal results assuming a period of equilibrium in the selection process. An existing theorem concerning the relationship

  7. Exchange rate predictability and state-of-the-art models

    OpenAIRE

    Yeșin, Pınar

    2016-01-01

    This paper empirically evaluates the predictive performance of the International Monetary Fund's (IMF) exchange rate assessments with respect to future exchange rate movements. The assessments of real trade-weighted exchange rates were conducted from 2006 to 2011, and were based on three state-of-the-art exchange rate models with a medium-term focus which were developed by the IMF. The empirical analysis using 26 advanced and emerging market economy currencies reveals that the "diagnosis" of ...

  8. Intelligent Online Marketing : Predicting Conversion Rate Of New Keywords

    OpenAIRE

    Engström, Tommy

    2013-01-01

    This thesis looks at the problem of predicting conversion rate of keywords in Google Adwords where little or no data for the keyword is available. Several methods are investigated and tested on data belonging to three different real world clients. The methods try to predict the conversion rate only given the keyword text. All methods are compared, using two different evaluation methods, with results showing good potential. Finally further improvements are suggested that could have a big impac...

  9. Money earlier or later? Simple heuristics explain intertemporal choices better than delay discounting does.

    Science.gov (United States)

    Ericson, Keith M Marzilli; White, John Myles; Laibson, David; Cohen, Jonathan D

    2015-06-01

    Heuristic models have been proposed for many domains involving choice. We conducted an out-of-sample, cross-validated comparison of heuristic models of intertemporal choice (which can account for many of the known intertemporal choice anomalies) and discounting models. Heuristic models outperformed traditional utility-discounting models, including models of exponential and hyperbolic discounting. The best-performing models predicted choices by using a weighted average of absolute differences and relative percentage differences of the attributes of the goods in a choice set. We concluded that heuristic models explain time-money trade-off choices in experiments better than do utility-discounting models. © The Author(s) 2015.

  10. Money Earlier or Later? Simple Heuristics Explain Intertemporal Choices Better than Delay Discounting1

    Science.gov (United States)

    Marzilli Ericson, Keith M.; White, John Myles; Laibson, David; Cohen, Jonathan D.

    2015-01-01

    Heuristic models have been proposed for many domains of choice. We compare heuristic models of intertemporal choice, which can account for many of the known intertemporal choice anomalies, to discounting models. We conduct an out-of-sample, cross-validated comparison of intertemporal choice models. Heuristic models outperform traditional utility discounting models, including models of exponential and hyperbolic discounting. The best performing models predict choices by using a weighted average of absolute differences and relative (percentage) differences of the attributes of the goods in a choice set. We conclude that heuristic models explain time-money tradeoff choices in experiments better than utility discounting models. PMID:25911124

  11. OPPORTUNITY COSTS OF REWARD DELAYS AND THE DISCOUNTING OF HYPOTHETICAL MONEY AND CIGARETTES

    Science.gov (United States)

    Johnson, Patrick S.; Herrmann, Evan S.; Johnson, Matthew W.

    2015-01-01

    Humans are reported to discount delayed rewards at lower rates than nonhumans. However, nonhumans are studied in tasks that restrict reinforcement during delays, whereas humans are typically studied in tasks that do not restrict reinforcement during delays. In nonhuman tasks, the opportunity cost of restricted reinforcement during delays may increase delay discounting rates. The present within-subjects study used online crowdsourcing (Amazon Mechanical Turk, or MTurk) to assess the discounting of hypothetical delayed money (and cigarettes in smokers) under four hypothetical framing conditions differing in the availability of reinforcement during delays. At one extreme, participants were free to leave their computer without returning, and engage in any behavior during reward delays (modeling typical human tasks). At the opposite extreme, participants were required to stay at their computer and engage in little other behavior during reward delays (modeling typical nonhuman tasks). Discounting rates increased as an orderly function of opportunity cost. Results also indicated predominantly hyperbolic discounting, the “magnitude effect,” steeper discounting of cigarettes than money, and positive correlations between discounting rates of these commodities. This is the first study to test the effects of opportunity costs on discounting, and suggests that procedural differences may partially account for observed species differences in discounting. PMID:25388973

  12. Cocaine dependent individuals discount future rewards more than future losses for both cocaine and monetary outcomes.

    Science.gov (United States)

    Johnson, Matthew W; Bruner, Natalie R; Johnson, Patrick S

    2015-01-01

    Cocaine dependence and other forms of drug dependence are associated with steeper devaluation of future outcomes (delay discounting). Although studies in this domain have typically assessed choices between monetary gains (e.g., receive less money now versus receive more money after a delay), delay discounting is also applicable to decisions involving losses (e.g., small loss now versus larger delayed loss), with gains typically discounted more than losses (the "sign effect"). It is also known that drugs are discounted more than equivalently valued money. In the context of drug dependence, however, relatively little is known about the discounting of delayed monetary and drug losses and the presence of the sign effect. In this within-subject, laboratory study, delay discounting for gains and losses was assessed for cocaine and money outcomes in cocaine-dependent individuals (n=89). Both cocaine and monetary gains were discounted at significantly greater rates than cocaine and monetary losses, respectively (i.e., the sign effect). Cocaine gains were discounted significantly more than monetary gains, but cocaine and monetary losses were discounted similarly. Results suggest that cocaine is discounted by cocaine-dependent individuals in a systematic manner similar to other rewards. Because the sign effect was shown for both cocaine and money, delayed aversive outcomes may generally have greater impact than delayed rewards in shaping present behavior in this population. Copyright © 2014. Published by Elsevier Ltd.

  13. Discounting and the social cost of carbon: A closer look at uncertainty

    NARCIS (Netherlands)

    Guo, J.K.; Hepburn, C.; Tol, R.S.J.; Anthoff, D.

    2006-01-01

    Recently, in the economics literature, several papers have put forward arguments for using a declining discount rate in social-cost benefit analysis. This paper examines the impact of employing a declining discount rate on the social cost of carbon-the marginal social damage from a ton of emitted

  14. Prediction of gamma exposure rates in large nuclear craters

    Energy Technology Data Exchange (ETDEWEB)

    Tami, Thomas M; Day, Walter C [U.S. Army Engineer Nuclear Cratering Group, Lawrence Radiation Laboratory, Livermore, CA (United States)

    1970-05-15

    In many civil engineering applications of nuclear explosives there is the need to reenter the crater and lip area as soon as possible after the detonation to carry out conventional construction activities. These construction activities, however, must be delayed until the gamma dose rate, or exposure rate, in and around the crater decays to acceptable levels. To estimate the time of reentry for post-detonation construction activities, the exposure rate in the crater and lip areas must be predicted as a function of time after detonation. An accurate prediction permits a project planner to effectively schedule post-detonation activities.

  15. Decision processes in choice overload: a product of delay and probability discounting?

    Science.gov (United States)

    Kaplan, Brent A; Reed, Derek D

    2013-07-01

    Recent research in the behavioral decision making literature has demonstrated that humans hyperbolically discount the subjective value of options as the number of options increases (Reed et al., 2012). These findings provide a cognitive-behavioral synthesis of the "choice overload" phenomenon, also known as the "paradox of choice." Specifically, these findings suggest that temporal discounting may serve as the underlying process contributing to this effect. As an extension, this study examined the effects of reward magnitude sizes had on rates temporal and options discounting. This manipulation was conducted to determine what role temporal discounting plays in discounting of options. The present results suggest that temporal discounting may not be the only process contributing to the choice overload effect. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. Discounting with Imperfect Collateral

    OpenAIRE

    Lou, Wujiang

    2017-01-01

    Cash collateral is perfect in that it provides simultaneous counterparty credit risk protection and derivatives funding. Securities are imperfect collateral, because of collateral segregation or differences in CSA haircuts and repo haircuts. Moreover, the collateral rate term structure is not observable in the repo market, for derivatives netting sets are perpetual while repo tenors are typically in months. This article synthesizes these effects into a derivative financing rate that replaces ...

  17. Predicting High Frequency Exchange Rates using Machine Learning

    OpenAIRE

    Palikuca, Aleksandar; Seidl,, Timo

    2016-01-01

    This thesis applies a committee of Artificial Neural Networks and Support Vector Machines on high-dimensional, high-frequency EUR/USD exchange rate data in an effort to predict directional market movements on up to a 60 second prediction horizon. The study shows that combining multiple classifiers into a committee produces improved precision relative to the best individual committee members and outperforms previously reported results. A trading simulation implementing the committee classifier...

  18. Stock price change rate prediction by utilizing social network activities.

    Science.gov (United States)

    Deng, Shangkun; Mitsubuchi, Takashi; Sakurai, Akito

    2014-01-01

    Predicting stock price change rates for providing valuable information to investors is a challenging task. Individual participants may express their opinions in social network service (SNS) before or after their transactions in the market; we hypothesize that stock price change rate is better predicted by a function of social network service activities and technical indicators than by a function of just stock market activities. The hypothesis is tested by accuracy of predictions as well as performance of simulated trading because success or failure of prediction is better measured by profits or losses the investors gain or suffer. In this paper, we propose a hybrid model that combines multiple kernel learning (MKL) and genetic algorithm (GA). MKL is adopted to optimize the stock price change rate prediction models that are expressed in a multiple kernel linear function of different types of features extracted from different sources. GA is used to optimize the trading rules used in the simulated trading by fusing the return predictions and values of three well-known overbought and oversold technical indicators. Accumulated return and Sharpe ratio were used to test the goodness of performance of the simulated trading. Experimental results show that our proposed model performed better than other models including ones using state of the art techniques.

  19. Stock Price Change Rate Prediction by Utilizing Social Network Activities

    Directory of Open Access Journals (Sweden)

    Shangkun Deng

    2014-01-01

    Full Text Available Predicting stock price change rates for providing valuable information to investors is a challenging task. Individual participants may express their opinions in social network service (SNS before or after their transactions in the market; we hypothesize that stock price change rate is better predicted by a function of social network service activities and technical indicators than by a function of just stock market activities. The hypothesis is tested by accuracy of predictions as well as performance of simulated trading because success or failure of prediction is better measured by profits or losses the investors gain or suffer. In this paper, we propose a hybrid model that combines multiple kernel learning (MKL and genetic algorithm (GA. MKL is adopted to optimize the stock price change rate prediction models that are expressed in a multiple kernel linear function of different types of features extracted from different sources. GA is used to optimize the trading rules used in the simulated trading by fusing the return predictions and values of three well-known overbought and oversold technical indicators. Accumulated return and Sharpe ratio were used to test the goodness of performance of the simulated trading. Experimental results show that our proposed model performed better than other models including ones using state of the art techniques.

  20. An analysis of the influence of discount sales promotion in consumer buying intent and the moderating effects of attractiveness

    Directory of Open Access Journals (Sweden)

    Fernando de Oliveira Santini

    2015-12-01

    Full Text Available ABSTRACT The purpose of this paper is to analyze the influence of discount sales promotion in the purchase intention and the moderating effects of attractiveness in the relationship between intention to purchase a discounted product and the impulsiveness, hedonic perception and financial risk. Thus, an experiment involving 613 students was conducted. The hypotheses predicted that a product with discount promotion would relate positively with impulsivity, as well as with a hedonic perception about the good offered, and negatively with the perception of financial risk associated with the product offered with discount. A positive moderation was expected of the perceived attractiveness of the announced discount promotion on the intentions of behaviors. The results confirmed the hypothesis, indicating positive effects of impulsivity and hedonic perception by purchasing the discounted products, in addition to the negative link between the intention of purchasing discounted products and the perception of a financial risk. The moderating effects were not confirmed. Final considerations conclude the work.

  1. Delay discounting of food by rhesus monkeys: Cocaine and food choice in isomorphic and allomorphic situations.

    Science.gov (United States)

    Huskinson, Sally L; Woolverton, William L; Green, Leonard; Myerson, Joel; Freeman, Kevin B

    2015-06-01

    Research on delay discounting has focused largely on nondrug reinforcers in an isomorphic context in which choice is between alternatives that involve the same type of reinforcer. Less often, delay discounting has been studied with drug reinforcers in a more ecologically valid allomorphic context where choice is between alternatives involving different types of reinforcers. The present experiment is the first to examine discounting of drug and nondrug reinforcers in both isomorphic and allomorphic situations using a theoretical model (i.e., the hyperbolic discounting function) that allows for comparisons of discounting rates between reinforcer types and amounts. The goal of the current experiment was to examine discounting of a delayed, nondrug reinforcer (food) by male rhesus monkeys when the immediate alternative was either food (isomorphic situation) or cocaine (allomorphic situation). In addition, we sought to determine whether there was a magnitude effect with delayed food in the allomorphic situation. Choice of immediate food and immediate cocaine increased with amount and dose, respectively. Choice functions for immediate food and cocaine generally shifted leftward as delay increased. Compared to isomorphic situations in which food was the immediate alternative, delayed food was discounted more steeply in allomorphic situations where cocaine was the immediate alternative. Notably, discounting was not affected by the magnitude of the delayed reinforcer. These data indicate that how steeply a delayed nondrug reinforcer is discounted may depend more on the qualitative characteristics of the immediate reinforcer and less on the magnitude of the delayed one. (c) 2015 APA, all rights reserved).

  2. Positive autobiographical memory retrieval reduces temporal discounting

    Science.gov (United States)

    Lempert, Karolina M; Speer, Megan E; Delgado, Mauricio R

    2017-01-01

    Abstract People generally prefer rewards sooner rather than later. This phenomenon, temporal discounting, underlies many societal problems, including addiction and obesity. One way to reduce temporal discounting is to imagine positive future experiences. Since there is overlap in the neural circuitry associated with imagining future experiences and remembering past events, here we investigate whether recalling positive memories can also promote more patient choice. We found that participants were more patient after retrieving positive autobiographical memories, but not when they recalled negative memories. Moreover, individuals were more impulsive after imagining novel positive scenes that were not related to their memories, showing that positive imagery alone does not drive this effect. Activity in the striatum and temporo parietal junction during memory retrieval predicted more patient choice, suggesting that to the extent that memory recall is rewarding and involves perspective-taking, it influences decision-making. Furthermore, representational similarity in the ventromedial prefrontal cortex between memory recall and decision phases correlated with the behavioral effect across participants. Thus, we have identified a novel manipulation for reducing temporal discounting—remembering the positive past—and have begun to characterize the psychological and neural mechanisms behind it. PMID:28655195

  3. Examining weight concern and delay discounting in adolescent females.

    Science.gov (United States)

    Thamotharan, Sneha; Lange, Krista; Ramos, Ashley; Fields, Sherecce

    2016-04-01

    Pediatric obesity is a growing public health concern that contributes to high rates of negative long-term physical and mental health outcomes. Research focused on identifying risk for pediatric obesity has linked delay discounting, or an inclination for immediate rewards, as well as weight concern to individuals with greater Body Mass Index (BMI). The current study seeks to fill a void in the literature by examining how these two variables interact to promote higher BMI in female adolescents. Adolescent (n=60) females between the ages of 13-19years (mage=17.45, SD=1.74) of age completed the Eating Disorder Examination Questionnaire (EDE-Q) and the Delay Discounting Questionnaire. A mediation model examined whether delay discounting accounted for the relationship between weight concern and BMI. Results indicate that in the current study weight concern was negatively related to delay discounting and delay discounting was negatively related to BMI. The overall model revealed that a partial mediation occurred [b=1.28, t(60)=4.92, pconcerns contribute to greater BMI. Nevertheless, the results indicate that prevention and interventions should identify females with high levels of both weight concern and impulsivity as an increased risk for experiencing pediatric obesity and long-term negative health outcomes. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Depletion of heterogeneous source species pools predicts future invasion rates

    Science.gov (United States)

    Andrew M. Liebhold; Eckehard G. Brockerhoff; Mark Kimberley; Jacqueline Beggs

    2017-01-01

    Predicting how increasing rates of global trade will result in new establishments of potentially damaging invasive species is a question of critical importance to the development of national and international policies aimed at minimizing future invasions. Centuries of historical movement and establishment of invading species may have depleted the supply of species...

  5. Compact Web browsing profiles for click-through rate prediction

    DEFF Research Database (Denmark)

    Fruergaard, Bjarne Ørum; Hansen, Lars Kai

    2014-01-01

    In real time advertising we are interested in finding features that improve click-through rate prediction. One source of available information is the bipartite graph of websites previously engaged by identifiable users. In this work, we investigate three different decompositions of such a graph...

  6. Cell membrane temperature rate sensitivity predicted from the Nernst equation.

    Science.gov (United States)

    Barnes, F S

    1984-01-01

    A hyperpolarized current is predicted from the Nernst equation for conditions of positive temperature derivatives with respect to time. This ion current, coupled with changes in membrane channel conductivities, is expected to contribute to a transient potential shift across the cell membrane for silent cells and to a change in firing rate for pacemaker cells.

  7. What Predicts Method Effects in Child Behavior Ratings

    Science.gov (United States)

    Low, Justin A.; Keith, Timothy Z.; Jensen, Megan

    2015-01-01

    The purpose of this research was to determine whether child, parent, and teacher characteristics such as sex, socioeconomic status (SES), parental depressive symptoms, the number of years of teaching experience, number of children in the classroom, and teachers' disciplinary self-efficacy predict deviations from maternal ratings in a…

  8. Predicting online ratings based on the opinion spreading process

    Science.gov (United States)

    He, Xing-Sheng; Zhou, Ming-Yang; Zhuo, Zhao; Fu, Zhong-Qian; Liu, Jian-Guo

    2015-10-01

    Predicting users' online ratings is always a challenge issue and has drawn lots of attention. In this paper, we present a rating prediction method by combining the user opinion spreading process with the collaborative filtering algorithm, where user similarity is defined by measuring the amount of opinion a user transfers to another based on the primitive user-item rating matrix. The proposed method could produce a more precise rating prediction for each unrated user-item pair. In addition, we introduce a tunable parameter λ to regulate the preferential diffusion relevant to the degree of both opinion sender and receiver. The numerical results for Movielens and Netflix data sets show that this algorithm has a better accuracy than the standard user-based collaborative filtering algorithm using Cosine and Pearson correlation without increasing computational complexity. By tuning λ, our method could further boost the prediction accuracy when using Mean Absolute Error (MAE) and Root Mean Squared Error (RMSE) as measurements. In the optimal cases, on Movielens and Netflix data sets, the corresponding algorithmic accuracy (MAE and RMSE) are improved 11.26% and 8.84%, 13.49% and 10.52% compared to the item average method, respectively.

  9. Functional leaf attributes predict litter decomposition rate in herbaceous plants

    NARCIS (Netherlands)

    Cornelissen, J. H C; Thompson, K.

    1997-01-01

    We tested the hypothesis that functional attributes of living leaves provide a basis for predicting the decomposition rate of leaf litter. The data were obtained from standardized screening tests on 38 British herbaceous species. Graminoid monocots had physically tougher leaves with higher silicon

  10. Prediction of maximal heart rate: comparison using a novel and ...

    African Journals Online (AJOL)

    Prediction of maximal heart rate: comparison using a novel and conventional equation. LR Keytel, E Mukwevho, MA Will, M Lambert. Abstract. No Abstract. African Journal for Physical, Health Education, Recreation and Dance Vol. 11(3) 2005: 269-277. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL ...

  11. Predictive Value of Respiratory Rate Thresholds in Pneumonia ...

    African Journals Online (AJOL)

    A study was carried out to determine the predictive value of respiratory rate in the clinical diagnosis of pneumonia in 101 children with respiratory symptoms of <28 days duration. Clinical, demographic and anthropometric variables were obtained at presentation while confirmation of the diagnosis was by a chest x-ray in ...

  12. Activity, exposure rate and spectrum prediction with Java programming

    International Nuclear Information System (INIS)

    Sahin, D.; Uenlue, K.

    2009-01-01

    In order to envision the radiation exposure during Neutron Activation Analysis (NAA) experiments, a software called Activity Predictor is developed using Java TM programming language. The Activity Predictor calculates activities, exposure rates and gamma spectra of activated samples for NAA experiments performed at Radiation Science and Engineering Center (RSEC), Penn State Breazeale Reactor (PSBR). The calculation procedure for predictions involves both analytical and Monte Carlo methods. The Activity Predictor software is validated with a series of activation experiments. It has been found that Activity Predictor software calculates the activities and exposure rates precisely. The software also predicts gamma spectrum for each measurement. The predicted spectra agreed partially with measured spectra. The error in net photo peak areas varied from 4.8 to 51.29%, which is considered to be due to simplistic modeling, statistical fluctuations and unknown contaminants in the samples. (author)

  13. Precise predictions for inclusive semi-tauonic B decay rate

    Energy Technology Data Exchange (ETDEWEB)

    Mannel, Thomas; Shahriaran, Farnoush [University of Siegen (Germany)

    2016-07-01

    We get Standard Model prediction for the decay rate of B → X{sub c}τν transitions. The triple differential decay rate has been derived including the nonperturbative corrections of order Λ{sub QCD}{sup 3}/m{sub b}{sup 3} and the leading O(α{sub s}) corrections. The total decay width is obtained by numerical integration with an estimated uncertainty of roughly 5%. We compare our result to the sum of the rates of the exclusive B → Dτν, B → D*τν and B → D**τν decays.

  14. Secretary Problems: Weights and Discounts

    OpenAIRE

    Babaioff, M.; Dinitz, M.; Gupta, A.; Immorlica, Nicole Simone; Talwar, K.

    2009-01-01

    textabstractThe classical secretary problem studies the problem of selecting online an element (a “secretary”) with maximum value in a randomly ordered sequence. The difficulty lies in the fact that an element must be either selected or discarded upon its arrival, and this decision is irrevocable. Constant-competitive algorithms are known for the classical secretary problems and several variants. We study the following two extensions of the secretary problem: In the discounted secretary probl...

  15. Dynamical instabilities in a simple minority game with discounting

    International Nuclear Information System (INIS)

    Challet, D; De Martino, A; Marsili, M

    2008-01-01

    We explore the effect of discounting and experimentation in a simple model of interacting adaptive agents. Agents belong to either of two types and each has to decide whether to participate in a game or not, the game being profitable when there is an excess of players of the other type. We find the emergence of large fluctuations as a result of the onset of a dynamical instability which may arise discontinuously (increasing the discount factor) or continuously (decreasing the experimentation rate). The phase diagram is characterized in detail and noise amplification close to a bifurcation point is identified as the physical mechanism behind the instability. (letter)

  16. Predicting basal metabolic rates in Malaysian adult elite athletes.

    Science.gov (United States)

    Wong, Jyh Eiin; Poh, Bee Koon; Nik Shanita, Safii; Izham, Mohd Mohamad; Chan, Kai Quin; Tai, Meng De; Ng, Wei Wei; Ismail, Mohd Noor

    2012-11-01

    This study aimed to measure the basal metabolic rate (BMR) of elite athletes and develop a gender specific predictive equation to estimate their energy requirements. 92 men and 33 women (aged 18-31 years) from 15 sports, who had been training six hours daily for at least one year, were included in the study. Body composition was measured using the bioimpedance technique, and BMR by indirect calorimetry. The differences between measured and estimated BMR using various predictive equations were calculated. The novel equation derived from stepwise multiple regression was evaluated using Bland and Altman analysis. The predictive equations of Cunningham and the Food and Agriculture Organization/World Health Organization/United Nations University either over- or underestimated the measured BMR by up to ± 6%, while the equations of Ismail et al, developed from the local non-athletic population, underestimated the measured BMR by 14%. The novel predictive equation for the BMR of athletes was BMR (kcal/day) = 669 + 13 (weight in kg) + 192 (gender: 1 for men and 0 for women) (R2 0.548; standard error of estimates 163 kcal). Predicted BMRs of elite athletes by this equation were within 1.2% ± 9.5% of the measured BMR values. The novel predictive equation presented in this study can be used to calculate BMR for adult Malaysian elite athletes. Further studies may be required to validate its predictive capabilities for other sports, nationalities and age groups.

  17. Predicting Atomic Decay Rates Using an Informational-Entropic Approach

    Science.gov (United States)

    Gleiser, Marcelo; Jiang, Nan

    2018-06-01

    We show that a newly proposed Shannon-like entropic measure of shape complexity applicable to spatially-localized or periodic mathematical functions known as configurational entropy (CE) can be used as a predictor of spontaneous decay rates for one-electron atoms. The CE is constructed from the Fourier transform of the atomic probability density. For the hydrogen atom with degenerate states labeled with the principal quantum number n, we obtain a scaling law relating the n-averaged decay rates to the respective CE. The scaling law allows us to predict the n-averaged decay rate without relying on the traditional computation of dipole matrix elements. We tested the predictive power of our approach up to n = 20, obtaining an accuracy better than 3.7% within our numerical precision, as compared to spontaneous decay tables listed in the literature.

  18. Predicting Atomic Decay Rates Using an Informational-Entropic Approach

    Science.gov (United States)

    Gleiser, Marcelo; Jiang, Nan

    2018-02-01

    We show that a newly proposed Shannon-like entropic measure of shape complexity applicable to spatially-localized or periodic mathematical functions known as configurational entropy (CE) can be used as a predictor of spontaneous decay rates for one-electron atoms. The CE is constructed from the Fourier transform of the atomic probability density. For the hydrogen atom with degenerate states labeled with the principal quantum number n, we obtain a scaling law relating the n-averaged decay rates to the respective CE. The scaling law allows us to predict the n-averaged decay rate without relying on the traditional computation of dipole matrix elements. We tested the predictive power of our approach up to n = 20, obtaining an accuracy better than 3.7% within our numerical precision, as compared to spontaneous decay tables listed in the literature.

  19. Modeling and predicting historical volatility in exchange rate markets

    Science.gov (United States)

    Lahmiri, Salim

    2017-04-01

    Volatility modeling and forecasting of currency exchange rate is an important task in several business risk management tasks; including treasury risk management, derivatives pricing, and portfolio risk evaluation. The purpose of this study is to present a simple and effective approach for predicting historical volatility of currency exchange rate. The approach is based on a limited set of technical indicators as inputs to the artificial neural networks (ANN). To show the effectiveness of the proposed approach, it was applied to forecast US/Canada and US/Euro exchange rates volatilities. The forecasting results show that our simple approach outperformed the conventional GARCH and EGARCH with different distribution assumptions, and also the hybrid GARCH and EGARCH with ANN in terms of mean absolute error, mean of squared errors, and Theil's inequality coefficient. Because of the simplicity and effectiveness of the approach, it is promising for US currency volatility prediction tasks.

  20. Parent Ratings of Impulsivity and Inhibition Predict State Testing Scores

    Directory of Open Access Journals (Sweden)

    Rebecca A. Lundwall

    2018-03-01

    Full Text Available One principle of cognitive development is that earlier intervention for educational difficulties tends to improve outcomes such as future educational and career success. One possible way to help students who struggle is to determine if they process information differently. Such determination might lead to clues for interventions. For example, early information processing requires attention before the information can be identified, encoded, and stored. The aim of the present study was to investigate whether parent ratings of inattention, inhibition, and impulsivity, and whether error rate on a reflexive attention task could be used to predict child scores on state standardized tests. Finding such an association could provide assistance to educators in identifying academically struggling children who might require targeted educational interventions. Children (N = 203 were invited to complete a peripheral cueing task (which measures the automatic reorienting of the brain’s attentional resources from one location to another. While the children completed the task, their parents completed a questionnaire. The questionnaire gathered information on broad indicators of child functioning, including observable behaviors of impulsivity, inattention, and inhibition, as well as state academic scores (which the parent retrieved online from their school. We used sequential regression to analyze contributions of error rate and parent-rated behaviors in predicting six academic scores. In one of the six analyses (for science, we found that the improvement was significant from the simplified model (with only family income, child age, and sex as predictors to the full model (adding error rate and three parent-rated behaviors. Two additional analyses (reading and social studies showed near significant improvement from simplified to full models. Parent-rated behaviors were significant predictors in all three of these analyses. In the reading score analysis

  1. Temporal discounting across three psychiatric disorders: Anorexia nervosa, obsessive compulsive disorder, and social anxiety disorder

    Science.gov (United States)

    Steinglass, Joanna E.; Lempert, Karolina M.; Choo, Tse-Hwei; Kimeldorf, Marcia B.; Wall, Melanie; Walsh, B. Timothy; Fyer, Abby J.; Schneier, Franklin R.; Simpson, H. Blair

    2018-01-01

    Background Temporal discounting refers to the tendency for rewards to lose value as the expected delay to receipt increases. Individuals with anorexia nervosa (AN) have been found to show reduced temporal discounting rates, indicating a greater preference for delayed rewards compared to healthy peers. Obsessive–compulsive disorder (OCD) and social anxiety disorder (SAD) commonly co-occur with AN, and anxiety has been related to development and prognosis of AN. We examined whether reduced temporal discounting is present across these potentially related disorders, and explored the relationship between temporal discounting and anxiety trans-diagnostically. Methods One hundred ninety six individuals (75 healthy controls (HC); 50 OCD; 27 AN; 44 SAD) completed two temporal discounting tasks in which they chose between smaller-sooner and larger-later monetary rewards. Two measures of discounting—discount rate and discount factor—were compared between diagnostic groups, and associations with anxious traits were examined. Results Individuals with AN showed decreased temporal discounting compared to HC. OCD and SAD groups did not differ significantly from HC. Across the sample, anxiety was associated with decreased discounting; more anxious individuals showed a greater preference for delayed reward. Conclusions We replicated the findings that individuals with AN show an increased preference for delayed reward relative to HC and that individuals with OCD do not differ from HC. We also showed that individuals with SAD do not differ from HC in discounting. Across this large sample, two measures of anxious temperament were associated with temporal discounting. These data raise new questions about the relationship between this dimensional trait and psychopathology. PMID:28009473

  2. Maximizing the model for Discounted Stream of Utility from ...

    African Journals Online (AJOL)

    Osagiede et al. (2009) considered an analytic model for maximizing discounted stream of utility from consumption when the rate of production is linear. A solution was provided to a level where methods of solving order differential equations will be applied, but they left off there, as a result of the mathematical complexity ...

  3. Prediction of interest rate using CKLS model with stochastic parameters

    International Nuclear Information System (INIS)

    Ying, Khor Chia; Hin, Pooi Ah

    2014-01-01

    The Chan, Karolyi, Longstaff and Sanders (CKLS) model is a popular one-factor model for describing the spot interest rates. In this paper, the four parameters in the CKLS model are regarded as stochastic. The parameter vector φ (j) of four parameters at the (J+n)-th time point is estimated by the j-th window which is defined as the set consisting of the observed interest rates at the j′-th time point where j≤j′≤j+n. To model the variation of φ (j) , we assume that φ (j) depends on φ (j−m) , φ (j−m+1) ,…, φ (j−1) and the interest rate r j+n at the (j+n)-th time point via a four-dimensional conditional distribution which is derived from a [4(m+1)+1]-dimensional power-normal distribution. Treating the (j+n)-th time point as the present time point, we find a prediction interval for the future value r j+n+1 of the interest rate at the next time point when the value r j+n of the interest rate is given. From the above four-dimensional conditional distribution, we also find a prediction interval for the future interest rate r j+n+d at the next d-th (d≥2) time point. The prediction intervals based on the CKLS model with stochastic parameters are found to have better ability of covering the observed future interest rates when compared with those based on the model with fixed parameters

  4. Prediction of interest rate using CKLS model with stochastic parameters

    Energy Technology Data Exchange (ETDEWEB)

    Ying, Khor Chia [Faculty of Computing and Informatics, Multimedia University, Jalan Multimedia, 63100 Cyberjaya, Selangor (Malaysia); Hin, Pooi Ah [Sunway University Business School, No. 5, Jalan Universiti, Bandar Sunway, 47500 Subang Jaya, Selangor (Malaysia)

    2014-06-19

    The Chan, Karolyi, Longstaff and Sanders (CKLS) model is a popular one-factor model for describing the spot interest rates. In this paper, the four parameters in the CKLS model are regarded as stochastic. The parameter vector φ{sup (j)} of four parameters at the (J+n)-th time point is estimated by the j-th window which is defined as the set consisting of the observed interest rates at the j′-th time point where j≤j′≤j+n. To model the variation of φ{sup (j)}, we assume that φ{sup (j)} depends on φ{sup (j−m)}, φ{sup (j−m+1)},…, φ{sup (j−1)} and the interest rate r{sub j+n} at the (j+n)-th time point via a four-dimensional conditional distribution which is derived from a [4(m+1)+1]-dimensional power-normal distribution. Treating the (j+n)-th time point as the present time point, we find a prediction interval for the future value r{sub j+n+1} of the interest rate at the next time point when the value r{sub j+n} of the interest rate is given. From the above four-dimensional conditional distribution, we also find a prediction interval for the future interest rate r{sub j+n+d} at the next d-th (d≥2) time point. The prediction intervals based on the CKLS model with stochastic parameters are found to have better ability of covering the observed future interest rates when compared with those based on the model with fixed parameters.

  5. Predicting rates of interspecific interaction from phylogenetic trees.

    Science.gov (United States)

    Nuismer, Scott L; Harmon, Luke J

    2015-01-01

    Integrating phylogenetic information can potentially improve our ability to explain species' traits, patterns of community assembly, the network structure of communities, and ecosystem function. In this study, we use mathematical models to explore the ecological and evolutionary factors that modulate the explanatory power of phylogenetic information for communities of species that interact within a single trophic level. We find that phylogenetic relationships among species can influence trait evolution and rates of interaction among species, but only under particular models of species interaction. For example, when interactions within communities are mediated by a mechanism of phenotype matching, phylogenetic trees make specific predictions about trait evolution and rates of interaction. In contrast, if interactions within a community depend on a mechanism of phenotype differences, phylogenetic information has little, if any, predictive power for trait evolution and interaction rate. Together, these results make clear and testable predictions for when and how evolutionary history is expected to influence contemporary rates of species interaction. © 2014 John Wiley & Sons Ltd/CNRS.

  6. Prediction of subjective ratings of emotional pictures by EEG features

    Science.gov (United States)

    McFarland, Dennis J.; Parvaz, Muhammad A.; Sarnacki, William A.; Goldstein, Rita Z.; Wolpaw, Jonathan R.

    2017-02-01

    Objective. Emotion dysregulation is an important aspect of many psychiatric disorders. Brain-computer interface (BCI) technology could be a powerful new approach to facilitating therapeutic self-regulation of emotions. One possible BCI method would be to provide stimulus-specific feedback based on subject-specific electroencephalographic (EEG) responses to emotion-eliciting stimuli. Approach. To assess the feasibility of this approach, we studied the relationships between emotional valence/arousal and three EEG features: amplitude of alpha activity over frontal cortex; amplitude of theta activity over frontal midline cortex; and the late positive potential over central and posterior mid-line areas. For each feature, we evaluated its ability to predict emotional valence/arousal on both an individual and a group basis. Twenty healthy participants (9 men, 11 women; ages 22-68) rated each of 192 pictures from the IAPS collection in terms of valence and arousal twice (96 pictures on each of 4 d over 2 weeks). EEG was collected simultaneously and used to develop models based on canonical correlation to predict subject-specific single-trial ratings. Separate models were evaluated for the three EEG features: frontal alpha activity; frontal midline theta; and the late positive potential. In each case, these features were used to simultaneously predict both the normed ratings and the subject-specific ratings. Main results. Models using each of the three EEG features with data from individual subjects were generally successful at predicting subjective ratings on training data, but generalization to test data was less successful. Sparse models performed better than models without regularization. Significance. The results suggest that the frontal midline theta is a better candidate than frontal alpha activity or the late positive potential for use in a BCI-based paradigm designed to modify emotional reactions.

  7. Neural congruence between intertemporal and interpersonal self-control: Evidence from delay and social discounting.

    Science.gov (United States)

    Hill, Paul F; Yi, Richard; Spreng, R Nathan; Diana, Rachel A

    2017-11-15

    Behavioral studies using delay and social discounting as indices of self-control and altruism, respectively, have revealed functional similarities between farsighted and social decisions. However, neural evidence for this functional link is lacking. Twenty-five young adults completed a delay and social discounting task during fMRI scanning. A spatiotemporal partial least squares analysis revealed that both forms of discounting were well characterized by a pattern of brain activity in areas comprising frontoparietal control, default, and mesolimbic reward networks. Both forms of discounting appear to draw on common neurocognitive mechanisms, regardless of whether choices involve intertemporal or interpersonal outcomes. We also observed neural profiles differentiating between high and low discounters. High discounters were well characterized by increased medial temporal lobe and limbic activity. In contrast, low discount rates were associated with activity in the medial prefrontal cortex and right temporoparietal junction. This pattern may reflect biological mechanisms underlying behavioral heterogeneity in discount rates. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Global warming: discounting is not the issue, but substitutability is

    International Nuclear Information System (INIS)

    Neumayer, E.

    1999-01-01

    The cost-benefit study of Nordhaus (1994) is representative for the neoclassical approach towards global warming. Nordhaus found that no substantial emission cuts are warranted. Most of his critics have concentrated on the issue of discounting and demanded that a lower discount rate should be applied. These criticisms first miss the point and second lead to ethically dubious, inconsistent conclusions and inefficient policy choices. They miss the point because the real problem of Nordhaus's methodology is his implicit underlying assumption of perfect substitutability between natural and other forms of capital. Given the validity of this assumption, lowering the rate of discount is inconsistent with current savings behaviour, is ethically dubious because future generations will be much richer than the current one anyway, and is inefficient because scarce financial resources are channelled into emissions abatement that exhibits rates of return far inferior to alternative public investments. Any call for aggressive emission abatement must therefore directly attack the perfect substitutability assumption of neoclassical economics. The real disagreement is about whether consumption growth can compensate for environmental degradation caused by global warming. Discounting is not the issue, but substitutability is. (author)

  9. Rate-Based Model Predictive Control of Turbofan Engine Clearance

    Science.gov (United States)

    DeCastro, Jonathan A.

    2006-01-01

    An innovative model predictive control strategy is developed for control of nonlinear aircraft propulsion systems and sub-systems. At the heart of the controller is a rate-based linear parameter-varying model that propagates the state derivatives across the prediction horizon, extending prediction fidelity to transient regimes where conventional models begin to lose validity. The new control law is applied to a demanding active clearance control application, where the objectives are to tightly regulate blade tip clearances and also anticipate and avoid detrimental blade-shroud rub occurrences by optimally maintaining a predefined minimum clearance. Simulation results verify that the rate-based controller is capable of satisfying the objectives during realistic flight scenarios where both a conventional Jacobian-based model predictive control law and an unconstrained linear-quadratic optimal controller are incapable of doing so. The controller is evaluated using a variety of different actuators, illustrating the efficacy and versatility of the control approach. It is concluded that the new strategy has promise for this and other nonlinear aerospace applications that place high importance on the attainment of control objectives during transient regimes.

  10. Improvement of energy expenditure prediction from heart rate during running

    International Nuclear Information System (INIS)

    Charlot, Keyne; Borne, Rachel; Richalet, Jean-Paul; Chapelot, Didier; Pichon, Aurélien; Cornolo, Jérémy; Brugniaux, Julien Vincent

    2014-01-01

    We aimed to develop new equations that predict exercise-induced energy expenditure (EE) more accurately than previous ones during running by including new parameters as fitness level, body composition and/or running intensity in addition to heart rate (HR). Original equations predicting EE were created from data obtained during three running intensities (25%, 50% and 70% of HR reserve) performed by 50 subjects. Five equations were conserved according to their accuracy assessed from error rates, interchangeability and correlations analyses: one containing only basic parameters, two containing VO 2max  or speed at VO 2max  and two including running speed with or without HR. Equations accuracy was further tested in an independent sample during a 40 min validation test at 50% of HR reserve. It appeared that: (1) the new basic equation was more accurate than pre-existing equations (R 2  0.809 versus. 0,737 respectively); (2) the prediction of EE was more accurate with the addition of VO 2max  (R 2  = 0.879); and (3) the equations containing running speed were the most accurate and were considered to have good agreement with indirect calorimetry. In conclusion, EE estimation during running might be significantly improved by including running speed in the predictive models, a parameter readily available with treadmill or GPS. (paper)

  11. Combining Review Text Content and Reviewer-Item Rating Matrix to Predict Review Rating

    Directory of Open Access Journals (Sweden)

    Bingkun Wang

    2016-01-01

    Full Text Available E-commerce develops rapidly. Learning and taking good advantage of the myriad reviews from online customers has become crucial to the success in this game, which calls for increasingly more accuracy in sentiment classification of these reviews. Therefore the finer-grained review rating prediction is preferred over the rough binary sentiment classification. There are mainly two types of method in current review rating prediction. One includes methods based on review text content which focus almost exclusively on textual content and seldom relate to those reviewers and items remarked in other relevant reviews. The other one contains methods based on collaborative filtering which extract information from previous records in the reviewer-item rating matrix, however, ignoring review textual content. Here we proposed a framework for review rating prediction which shows the effective combination of the two. Then we further proposed three specific methods under this framework. Experiments on two movie review datasets demonstrate that our review rating prediction framework has better performance than those previous methods.

  12. Combining Review Text Content and Reviewer-Item Rating Matrix to Predict Review Rating

    Science.gov (United States)

    Wang, Bingkun; Huang, Yongfeng; Li, Xing

    2016-01-01

    E-commerce develops rapidly. Learning and taking good advantage of the myriad reviews from online customers has become crucial to the success in this game, which calls for increasingly more accuracy in sentiment classification of these reviews. Therefore the finer-grained review rating prediction is preferred over the rough binary sentiment classification. There are mainly two types of method in current review rating prediction. One includes methods based on review text content which focus almost exclusively on textual content and seldom relate to those reviewers and items remarked in other relevant reviews. The other one contains methods based on collaborative filtering which extract information from previous records in the reviewer-item rating matrix, however, ignoring review textual content. Here we proposed a framework for review rating prediction which shows the effective combination of the two. Then we further proposed three specific methods under this framework. Experiments on two movie review datasets demonstrate that our review rating prediction framework has better performance than those previous methods. PMID:26880879

  13. Combining Review Text Content and Reviewer-Item Rating Matrix to Predict Review Rating.

    Science.gov (United States)

    Wang, Bingkun; Huang, Yongfeng; Li, Xing

    2016-01-01

    E-commerce develops rapidly. Learning and taking good advantage of the myriad reviews from online customers has become crucial to the success in this game, which calls for increasingly more accuracy in sentiment classification of these reviews. Therefore the finer-grained review rating prediction is preferred over the rough binary sentiment classification. There are mainly two types of method in current review rating prediction. One includes methods based on review text content which focus almost exclusively on textual content and seldom relate to those reviewers and items remarked in other relevant reviews. The other one contains methods based on collaborative filtering which extract information from previous records in the reviewer-item rating matrix, however, ignoring review textual content. Here we proposed a framework for review rating prediction which shows the effective combination of the two. Then we further proposed three specific methods under this framework. Experiments on two movie review datasets demonstrate that our review rating prediction framework has better performance than those previous methods.

  14. CREME96 and Related Error Rate Prediction Methods

    Science.gov (United States)

    Adams, James H., Jr.

    2012-01-01

    Predicting the rate of occurrence of single event effects (SEEs) in space requires knowledge of the radiation environment and the response of electronic devices to that environment. Several analytical models have been developed over the past 36 years to predict SEE rates. The first error rate calculations were performed by Binder, Smith and Holman. Bradford and Pickel and Blandford, in their CRIER (Cosmic-Ray-Induced-Error-Rate) analysis code introduced the basic Rectangular ParallelePiped (RPP) method for error rate calculations. For the radiation environment at the part, both made use of the Cosmic Ray LET (Linear Energy Transfer) spectra calculated by Heinrich for various absorber Depths. A more detailed model for the space radiation environment within spacecraft was developed by Adams and co-workers. This model, together with a reformulation of the RPP method published by Pickel and Blandford, was used to create the CR ME (Cosmic Ray Effects on Micro-Electronics) code. About the same time Shapiro wrote the CRUP (Cosmic Ray Upset Program) based on the RPP method published by Bradford. It was the first code to specifically take into account charge collection from outside the depletion region due to deformation of the electric field caused by the incident cosmic ray. Other early rate prediction methods and codes include the Single Event Figure of Merit, NOVICE, the Space Radiation code and the effective flux method of Binder which is the basis of the SEFA (Scott Effective Flux Approximation) model. By the early 1990s it was becoming clear that CREME and the other early models needed Revision. This revision, CREME96, was completed and released as a WWW-based tool, one of the first of its kind. The revisions in CREME96 included improved environmental models and improved models for calculating single event effects. The need for a revision of CREME also stimulated the development of the CHIME (CRRES/SPACERAD Heavy Ion Model of the Environment) and MACREE (Modeling and

  15. Aspect-Aware Latent Factor Model: Rating Prediction with Ratings and Reviews

    OpenAIRE

    Cheng, Zhiyong; Ding, Ying; Zhu, Lei; Kankanhalli, Mohan

    2018-01-01

    Although latent factor models (e.g., matrix factorization) achieve good accuracy in rating prediction, they suffer from several problems including cold-start, non-transparency, and suboptimal recommendation for local users or items. In this paper, we employ textual review information with ratings to tackle these limitations. Firstly, we apply a proposed aspect-aware topic model (ATM) on the review text to model user preferences and item features from different aspects, and estimate the aspect...

  16. The Dividend-Price Ratio and Expectations of Future Dividends and Discount Factors

    OpenAIRE

    John Y. Campbell; Robert J. Shiller

    1986-01-01

    A linearization of a rational expectations present value model for corporate stock prices produces a simple relation between the log dividend-price ratio and mathematical expectations of future log real dividend changes and future real discount rates. This relation can be tested using vector autoregressive methods. Three versions of the linearized model, differing in the measure of discount rates, are tested for U. S. time series 1871-1986: versions using real interest rate data, aggregate re...

  17. Mobile Phone-Based Mood Ratings Prospectively Predict Psychotherapy Attendance.

    Science.gov (United States)

    Bruehlman-Senecal, Emma; Aguilera, Adrian; Schueller, Stephen M

    2017-09-01

    Psychotherapy nonattendance is a costly and pervasive problem. While prior research has identified stable patient-level predictors of attendance, far less is known about dynamic (i.e., time-varying) factors. Identifying dynamic predictors can clarify how clinical states relate to psychotherapy attendance and inform effective "just-in-time" interventions to promote attendance. The present study examines whether daily mood, as measured by responses to automated mobile phone-based text messages, prospectively predicts attendance in group cognitive-behavioral therapy (CBT) for depression. Fifty-six Spanish-speaking Latino patients with elevated depressive symptoms (46 women, mean age=50.92years, SD=10.90years), enrolled in a manualized program of group CBT, received daily automated mood-monitoring text messages. Patients' daily mood ratings, message response rate, and delay in responding were recorded. Patients' self-reported mood the day prior to a scheduled psychotherapy session significantly predicted attendance, even after controlling for patients' prior attendance history and age (OR=1.33, 95% CI [1.04, 1.70], p=.02). Positive mood corresponded to a greater likelihood of attendance. Our results demonstrate the clinical utility of automated mood-monitoring text messages in predicting attendance. These results underscore the value of text messaging, and other mobile technologies, as adjuncts to psychotherapy. Future work should explore the use of such monitoring to guide interventions to increase attendance, and ultimately the efficacy of psychotherapy. Copyright © 2017. Published by Elsevier Ltd.

  18. Low Discounting Behavior among Small-Scale Fishers in Fiji and Sabah, Malaysia

    Directory of Open Access Journals (Sweden)

    Louise S. L. Teh

    2011-06-01

    Full Text Available Understanding the socio-economic factors that are associated with fishers’ willingness to delay gratification may be useful for designing appropriate fisheries management and conservation policies. We aim to identify the predictors of low discounting behaviour among fishers, which is analogous to having a longer-term outlook. We base our empirical study on two small-scale tropical reef fisheries in Sabah, Malaysia, and Fiji. We use an experimental approach to identify fishers with low discount rates, and then use a logistic regression model to identify predictors of low discount rates. We find that 42% of the respondents have low discount rates, and that site and village level variables are significant predictors of low discount rates. Within Sabah and Fiji, boat ownership and relative catch differentiate low discounting from non-low discounting fishers, but these variables have contradictory effects in Sabah and Fiji. Overall, our results imply that a substantial proportion of reef fishers may be willing to engage in conservation initiatives; however, local socio-cultural, economic, and ecological conditions have to be considered first during the process of designing management interventions.

  19. Predicting work Performance through selection interview ratings and Psychological assessment

    Directory of Open Access Journals (Sweden)

    Liziwe Nzama

    2008-11-01

    Full Text Available The aim of the study was to establish whether selection interviews used in conjunction with psychological assessments of personality traits and cognitive functioning contribute to predicting work performance. The sample consisted of 102 managers who were appointed recently in a retail organisation. The independent variables were selection interview ratings obtained on the basis of structured competency-based interview schedules by interviewing panels, fve broad dimensions of personality defned by the Five Factor Model as measured by the 15 Factor Questionnaire (15FQ+, and cognitive processing variables (current level of work, potential level of work, and 12 processing competencies measured by the Cognitive Process Profle (CPP. Work performance was measured through annual performance ratings that focused on measurable outputs of performance objectives. Only two predictor variables correlated statistically signifcantly with the criterion variable, namely interview ratings (r = 0.31 and CPP Verbal Abstraction (r = 0.34. Following multiple regression, only these variables contributed signifcantly to predicting work performance, but only 17.8% of the variance of the criterion was accounted for.

  20. Evaluation of Deep Discount Fare Strategies

    Science.gov (United States)

    1995-08-01

    This report evaluates the success of a fare pricing strategy known as deep discounting, that entails the bulk sale of transit tickets or tokens to customers at a significant discount compared to the full fare single ticket price. This market-driven s...

  1. Regression Models and Fuzzy Logic Prediction of TBM Penetration Rate

    Directory of Open Access Journals (Sweden)

    Minh Vu Trieu

    2017-03-01

    Full Text Available This paper presents statistical analyses of rock engineering properties and the measured penetration rate of tunnel boring machine (TBM based on the data of an actual project. The aim of this study is to analyze the influence of rock engineering properties including uniaxial compressive strength (UCS, Brazilian tensile strength (BTS, rock brittleness index (BI, the distance between planes of weakness (DPW, and the alpha angle (Alpha between the tunnel axis and the planes of weakness on the TBM rate of penetration (ROP. Four (4 statistical regression models (two linear and two nonlinear are built to predict the ROP of TBM. Finally a fuzzy logic model is developed as an alternative method and compared to the four statistical regression models. Results show that the fuzzy logic model provides better estimations and can be applied to predict the TBM performance. The R-squared value (R2 of the fuzzy logic model scores the highest value of 0.714 over the second runner-up of 0.667 from the multiple variables nonlinear regression model.

  2. Regression Models and Fuzzy Logic Prediction of TBM Penetration Rate

    Science.gov (United States)

    Minh, Vu Trieu; Katushin, Dmitri; Antonov, Maksim; Veinthal, Renno

    2017-03-01

    This paper presents statistical analyses of rock engineering properties and the measured penetration rate of tunnel boring machine (TBM) based on the data of an actual project. The aim of this study is to analyze the influence of rock engineering properties including uniaxial compressive strength (UCS), Brazilian tensile strength (BTS), rock brittleness index (BI), the distance between planes of weakness (DPW), and the alpha angle (Alpha) between the tunnel axis and the planes of weakness on the TBM rate of penetration (ROP). Four (4) statistical regression models (two linear and two nonlinear) are built to predict the ROP of TBM. Finally a fuzzy logic model is developed as an alternative method and compared to the four statistical regression models. Results show that the fuzzy logic model provides better estimations and can be applied to predict the TBM performance. The R-squared value (R2) of the fuzzy logic model scores the highest value of 0.714 over the second runner-up of 0.667 from the multiple variables nonlinear regression model.

  3. Proton upset rate prediction: a new sensitive volume concept definition

    International Nuclear Information System (INIS)

    Inguimbert, Christophe

    1999-01-01

    We present a model for predicting proton induced single event upset rate. The approach uses heavy ion cross section experimental data combined with nuclear reaction calculations in order to determine the proton upset cross section. The p+Si nuclear reaction as well as the Si(p, p)Si Coulombic scattering are described. The upset rate calculation depends on the energy deposited available in the charge collection region (sensitive region). This region is treated as a rectangular parallelepiped of thickness d at depth h. The sensitive thickness d is used as an input parameter in our model we have developed an original method to probe the sensitive region to evaluate d with reasonable accuracy d. We use short range ions and we propose a new mathematical analysis of these experimental data to determine h and d. This method consists in de-convoluting the heavy ion upset cross section σ_S_E_U(r) by the LET function of the incident ion LET(r) (r is the range of the incident ion). Our results are in relatively good agreement with other models. The accuracy of the method allows us to discuss the validity of the sensitive volume concept. Furthermore, we extrapolate an internal gain factor α that permit to take into account the charge collection mechanisms. α and d serve for quick and reasonably accurate prediction of proton induced SEU cross section in microelectronic devices. (author) [fr

  4. Kinetics of protein–ligand unbinding: Predicting pathways, rates, and rate-limiting steps

    Science.gov (United States)

    Tiwary, Pratyush; Limongelli, Vittorio; Salvalaglio, Matteo; Parrinello, Michele

    2015-01-01

    The ability to predict the mechanisms and the associated rate constants of protein–ligand unbinding is of great practical importance in drug design. In this work we demonstrate how a recently introduced metadynamics-based approach allows exploration of the unbinding pathways, estimation of the rates, and determination of the rate-limiting steps in the paradigmatic case of the trypsin–benzamidine system. Protein, ligand, and solvent are described with full atomic resolution. Using metadynamics, multiple unbinding trajectories that start with the ligand in the crystallographic binding pose and end with the ligand in the fully solvated state are generated. The unbinding rate koff is computed from the mean residence time of the ligand. Using our previously computed binding affinity we also obtain the binding rate kon. Both rates are in agreement with reported experimental values. We uncover the complex pathways of unbinding trajectories and describe the critical rate-limiting steps with unprecedented detail. Our findings illuminate the role played by the coupling between subtle protein backbone fluctuations and the solvation by water molecules that enter the binding pocket and assist in the breaking of the shielded hydrogen bonds. We expect our approach to be useful in calculating rates for general protein–ligand systems and a valid support for drug design. PMID:25605901

  5. Discounting of Condom-Protected Sex as a Measure of High Risk for Sexually Transmitted Infection Among College Students.

    Science.gov (United States)

    Collado, Anahí; Johnson, Patrick S; Loya, Jennifer M; Johnson, Matthew W; Yi, Richard

    2017-10-01

    The study examined sexual delay discounting, or the devaluation of condom-protected sex in the face of delay, as a risk factor for sexually transmitted infection (STI) among college students. Participants (143 females, 117 males) completed the sexual delay discounting task (Johnson & Bruner, 2012) and questionnaires of risky sexual behavior, risk perception, and knowledge. Participants exhibited steeper sexual delay discounting (above and beyond general likelihood of having unprotected sex) when partners were viewed as more desirable or less likely to have a STI, with males demonstrating greater sexual delay discounting than females across most conditions. Importantly, greater self-reported risky sexual behaviors were associated with higher rates of sexual delay discounting, but not with likelihood of using a condom in the absence of delay. These results provide support for considering sexual delay discounting, with particular emphasis on potential delays to condom use, as a risk factor for STI among college students.

  6. Exchanging the liquidity hypothesis: Delay discounting of money and self-relevant non-money rewards.

    Science.gov (United States)

    Stuppy-Sullivan, Allison M; Tormohlen, Kayla N; Yi, Richard

    2016-01-01

    Evidence that primary rewards (e.g., food and drugs of abuse) are discounted more than money is frequently attributed to money's high degree of liquidity, or exchangeability for many commodities. The present study provides some evidence against this liquidity hypothesis by contrasting delay discounting of monetary rewards (liquid) and non-monetary commodities (non-liquid) that are self-relevant and utility-matched. Ninety-seven (97) undergraduate students initially completed a conventional binary-choice delay discounting of money task. Participants returned one week later and completed a self-relevant commodity delay discounting task. Both conventional hypothesis testing and more-conservative tests of statistical equivalence revealed correspondence in rate of delay discounting of money and self-relevant commodities, and in one magnitude condition, less discounting for the latter. The present results indicate that liquidity of money cannot fully account for the lower rate of delay discounting compared to non-money rewards. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Trading Later Rewards for Current Pleasure: Pornography Consumption and Delay Discounting.

    Science.gov (United States)

    Negash, Sesen; Sheppard, Nicole Van Ness; Lambert, Nathaniel M; Fincham, Frank D

    2016-01-01

    Internet pornography is a multi-billion-dollar industry that has grown increasingly accessible. Delay discounting involves devaluing larger, later rewards in favor of smaller, more immediate rewards. The constant novelty and primacy of sexual stimuli as particularly strong natural rewards make Internet pornography a unique activator of the brain's reward system, thereby having implications for decision-making processes. Based on theoretical studies of evolutionary psychology and neuroeconomics, two studies tested the hypothesis that consuming Internet pornography would relate to higher rates of delay discounting. Study 1 used a longitudinal design. Participants completed a pornography use questionnaire and a delay discounting task at Time 1 and then again four weeks later. Participants reporting higher initial pornography use demonstrated a higher delay discounting rate at Time 2, controlling for initial delay discounting. Study 2 tested for causality with an experimental design. Participants were randomly assigned to abstain from either their favorite food or pornography for three weeks. Participants who abstained from pornography use demonstrated lower delay discounting than participants who abstained from their favorite food. The finding suggests that Internet pornography is a sexual reward that contributes to delay discounting differently than other natural rewards. Theoretical and clinical implications of these studies are highlighted.

  8. Urate predicts rate of clinical decline in Parkinson disease

    Science.gov (United States)

    Ascherio, Alberto; LeWitt, Peter A.; Xu, Kui; Eberly, Shirley; Watts, Arthur; Matson, Wayne R.; Marras, Connie; Kieburtz, Karl; Rudolph, Alice; Bogdanov, Mikhail B.; Schwid, Steven R.; Tennis, Marsha; Tanner, Caroline M.; Beal, M. Flint; Lang, Anthony E.; Oakes, David; Fahn, Stanley; Shoulson, Ira; Schwarzschild, Michael A.

    2009-01-01

    Context The risk of Parkinson disease (PD) and its rate of progression may decline with increasing blood urate, a major antioxidant. Objective To determine whether serum and cerebrospinal fluid (CSF) concentrations of urate predict clinical progression in patients with PD. Design, Setting, and Participants 800 subjects with early PD enrolled in the DATATOP trial. Pre-treatment urate was measured in serum for 774 subjects and in CSF for 713. Main Outcome Measures Treatment-, age- and sex-adjusted hazard ratios (HRs) for clinical disability requiring levodopa therapy, the pre-specified primary endpoint. Results The HR of progressing to endpoint decreased with increasing serum urate (HR for 1 standard deviation increase = 0.82; 95% CI = 0.73 to 0.93). In analyses stratified by α-tocopherol treatment (2,000 IU/day), a decrease in the HR for the primary endpoint was seen only among subjects not treated with α-tocopherol (HR = 0.75; 95% CI = 0.62 to 0.89, versus those treated HR = 0.90; 95% CI = 0.75 to 1.08). Results were similar for the rate of change in the United Parkinson Disease Rating Scale (UPDRS). CSF urate was also inversely related to both the primary endpoint (HR for highest versus lowest quintile = 0.65; 95% CI: 0.54 to 0.96) and to the rate of change in UPDRS. As with serum urate, these associations were present only among subjects not treated with α-tocopherol. Conclusion Higher serum and CSF urate at baseline were associated with slower rates of clinical decline. The findings strengthen the link between urate and PD and the rationale for considering CNS urate elevation as a potential strategy to slow PD progression. PMID:19822770

  9. A prediction of rate-dependent behaviour in ferroelectric polycrystals

    International Nuclear Information System (INIS)

    Kim, Sang-Joo

    2007-01-01

    Rate-dependent behaviour of a polycrystalline ferroelectric material is predicted based on thermal activation theory and a representative volume element model. First, the behaviour of a ferroelectric single crystal is calculated from a recently proposed three-dimensional free energy model [S.J. Kim, S. Seelecke, Int. J. Solids Struct. 44 (2007) 1196-1209]. Then, from the calculated single crystal responses, poling behaviour of a ferroelectric polycrystal is obtained in three different ways, two representative volume element models and Gaussian integration method. It is found that a dodecahedron representative volume element consisting of 210 crystallites is the best choice among the three methods. Finally, the behaviour of a ferroelectric polycrystal under various electric and stress loads is calculated using the chosen RVE model. The calculated responses are compared qualitatively with experimental observations, and the effects of crystal orientation and polycrystallinity are discussed

  10. A model for predicting wear rates in tooth enamel.

    Science.gov (United States)

    Borrero-Lopez, Oscar; Pajares, Antonia; Constantino, Paul J; Lawn, Brian R

    2014-09-01

    It is hypothesized that wear of enamel is sensitive to the presence of sharp particulates in oral fluids and masticated foods. To this end, a generic model for predicting wear rates in brittle materials is developed, with specific application to tooth enamel. Wear is assumed to result from an accumulation of elastic-plastic micro-asperity events. Integration over all such events leads to a wear rate relation analogous to Archard׳s law, but with allowance for variation in asperity angle and compliance. The coefficient K in this relation quantifies the wear severity, with an arbitrary distinction between 'mild' wear (low K) and 'severe' wear (high K). Data from the literature and in-house wear-test experiments on enamel specimens in lubricant media (water, oil) with and without sharp third-body particulates (silica, diamond) are used to validate the model. Measured wear rates can vary over several orders of magnitude, depending on contact asperity conditions, accounting for the occurrence of severe enamel removal in some human patients (bruxing). Expressions for the depth removal rate and number of cycles to wear down occlusal enamel in the low-crowned tooth forms of some mammals are derived, with tooth size and enamel thickness as key variables. The role of 'hard' versus 'soft' food diets in determining evolutionary paths in different hominin species is briefly considered. A feature of the model is that it does not require recourse to specific material removal mechanisms, although processes involving microplastic extrusion and microcrack coalescence are indicated. Published by Elsevier Ltd.

  11. Social interaction anxiety and the discounting of positive interpersonal events.

    Science.gov (United States)

    Vassilopoulos, Stephanos P; Banerjee, Robin

    2010-10-01

    Recent research has indicated that individuals with social interaction anxiety make biased interpretations of positive social interactions, with greater general apprehension in response to such events and more negative predictions about the future. There has also been some preliminary evidence for a second facet of interpretation bias, namely a failure to accept others' positive reactions at face value, but this has so far not been adequately studied. The present study developed a new measure of this "discounting" dimension and utilized a nonclinical sample of undergraduate students to provide an initial analysis of the scale. Results provide early support for the psychometric properties of our scale, and indicate that discounting mediates the relationship between social interaction anxiety and low positive affect, over and above the previously studied aspect of positive event interpretation bias. The implications for treatment interventions and further research are discussed.

  12. Delay discounting, self-control, and substance use among adult drug court participants.

    Science.gov (United States)

    Jones, Craig G A; Fearnley, Helen; Panagiotopoulos, Barbara; Kemp, Richard I

    2015-08-01

    The current study examined the relationship between two measures of impulsiveness and the odds of substance use among a sample of participants on an Australian drug court (n=80). Participants completed a computer-based delay discounting task, a paper-based delay discounting task, and a questionnaire-based measure of self-control. The delay discounting tasks measured individual differences in the value attributed to distal outcomes, which is one aspect of impulsive behavior that has been found to be over-represented among illicit drug users. The relationship between the measures of impulsiveness and the odds of substance use was assessed by fitting longitudinal panel regression models with adjustment for informative treatment dropout. Consistent with previous research, drug court participants were found to have higher discount rates (i.e. were more impulsive) than a noncriminal population of university students (n=101). Drug court participants also discounted delayed gains more than delayed losses. Delay discounting was not significantly associated with the odds of substance use on the drug court program. There was a positive relationship between the survey-based measure of impulsivity and the mean substance use frequency. The authors conclude that impulsivity is correlated with substance use among drug court participants but not when measuring impulsivity using a delay discounting paradigm.

  13. Psychological aspects of nuclear waste disposal: Long time perception and the question of discounting of risks

    International Nuclear Information System (INIS)

    Karlsson, G.; Svenson, O.

    1988-01-01

    Subjects of different ages and basic training indicated how they perceived risks related to spent nuclear fuel storage and located at different points of time into the future. The results indicated that minorities in all groups, ranging from about 10 to 40%, did not want to discount risks into the future. Those who discounted exhibited great inter and intra group variability. The physical discounting curves for e.g. both total radiation and for Pu-239 and -240 are within the range of curves generated by the groups for subjective discounting of risk. Politicians and experts were attributed equal shares of responsibility for risks of spent nuclear fuel in the future. About 10% to 40% of the subjects did not wish to discount responsibility. Discounting rates for those discounting varied so that some subjects decreased the level of responsibility to less than half 10 000 years into the future while others attributed this level of responsibility for 100 000 years and more. (orig./HP)

  14. Validation of resting metabolic rate prediction equations for teenagers

    Directory of Open Access Journals (Sweden)

    Paulo Henrique Santos da Fonseca

    2007-09-01

    Full Text Available The resting metabolic rate (RMR can be defi ned as the minimum rate of energy spent and represents the main component of the energetic outlay. The purpose of this study is to validate equations to predict the resting metabolic rate in teenagers (103 individuals, being 51 girls and 52 boys, with age between 10 and 17 years from Florianópolis – SC – Brazil. It was measured: the body weight, body height, skinfolds and obtained the lean and body fat mass through bioimpedance. The nonproteic RMR was measured by Weir’s equation (1949, utilizing AeroSport TEEM-100 gas analyzer. The studied equations were: Harry and Benedict (1919, Schofi eld (1985, WHO/FAO/UNU (1985, Henry and Rees (1991, Molnár et al. (1998, Tverskaya et al. (1998 and Müller et al. (2004. In order to study the cross-validation of the RMR prediction equations and its standard measure (Weir 1949, the following statistics procedure were calculated: Pearson’s correlation (r ≥ 0.70, the “t” test with the signifi cance level of p0.05 in relation to the standard measure, with exception of the equations suggested for Tverskaya et al. (1998, and the two models of Müller et al (2004. Even though there was not a signifi cant difference, only the models considered for Henry and Rees (1991, and Molnár et al. (1995 had gotten constant error variation under 5%. All the equations analyzed in the study in girls had not reached criterion of correlation values of 0.70 with the indirect calorimetry. Analyzing the prediction equations of RMR in boys, all of them had moderate correlation coeffi cients with the indirect calorimetry, however below 0.70. Only the equation developed for Tverskaya et al. (1998 presented differences (p ABSTRACT0,05 em relação à medida padrão (Weir 1949, com exceção das equações sugeridas por Tverskaya et al. (1998 e os dois modelos de Müller et al (2004. Mesmo não havendo diferença signifi cativa, somente os modelos propostos por Henry e Rees (1991

  15. Time management problems and discounted utility.

    Science.gov (United States)

    König, Cornelius J; Kleinmann, Martin

    2007-05-01

    The lens of behavioral decision theory offers a new perspective for research on time management. The basic idea of this approach is that people discount future consequences of their time management decisions, meaning that they work on tasks with smaller but sooner outcomes rather than on tasks with larger but later outcomes. The authors performed 2 experimental studies to test whether people are sensitive to differences in the discounted utility of time management decisions. In Experiment 1, they used vignettes of typical time management situations; Experiment 2 was a laboratory simulation (an in-basket task that was part of a training assessment). Participants in both studies were German students. As expected, manipulating the discounted utility of options resulted in different time management decisions. In Experiment 1, reactions to time management situations were judged as less likely if the reactions had lower discounted utilities. In Experiment 2, people spent less time on an interruption.

  16. 7 CFR 1786.153 - Discounted present value.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 12 2010-01-01 2010-01-01 false Discounted present value. 1786.153 Section 1786.153... Discounted Prepayments on RUS Electric Loans § 1786.153 Discounted present value. (a) The discounted present value shall be calculated by summing the present values of all remaining payments on all Qualified Notes...

  17. 7 CFR 1786.53 - Discounted present value.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 12 2010-01-01 2010-01-01 false Discounted present value. 1786.53 Section 1786.53... Special Discounted Prepayments on RUS Direct/Insured Loans § 1786.53 Discounted present value. The Discounted Present Value shall be calculated five business days before prepayment is made by summing the...

  18. TD Waterhouse discount brokerage: a competitive strategy

    OpenAIRE

    Dangerfield, Catherine

    2007-01-01

    This paper provides a strategic analysis of TD Waterhouse (TDW), the discount brokerage provider within TD Bank Financial Group (TDBFG). Discount brokerage in Canada is an increasingly lucrative industry and contributes significantly to the bottom lines of every major financial institution in the country. It is also a rapidly changing and intensely price-competitive industry in which an explicit, educated business strategy is of the utmost importance. TDW currently employs a somewhat ambiguou...

  19. Discounting Models for Outcomes over Continuous Time

    DEFF Research Database (Denmark)

    Harvey, Charles M.; Østerdal, Lars Peter

    Events that occur over a period of time can be described either as sequences of outcomes at discrete times or as functions of outcomes in an interval of time. This paper presents discounting models for events of the latter type. Conditions on preferences are shown to be satisfied if and only if t...... if the preferences are represented by a function that is an integral of a discounting function times a scale defined on outcomes at instants of time....

  20. Individual differences in delay discounting under acute stress: the role of trait perceived stress

    Directory of Open Access Journals (Sweden)

    Karolina M. Lempert

    2012-07-01

    Full Text Available Delay discounting refers to the reduction of the value of a future reward as the delay to that reward increases. The rate at which individuals discount future rewards varies as a function of both individual and contextual differences, and high delay discounting rates have been linked with problematic behaviors, including drug abuse and gambling. The current study investigated the effects of acute anticipatory stress on delay discounting, while considering two important factors: individual perceptions of stress and whether the stressful situation is future-focused or present-focused. Half of the participants experienced acute stress by anticipating giving a videotaped speech. This stress was either future-oriented (speech about future job or present-oriented (speech about physical appearance. They then performed a delay discounting task, in which they chose between smaller, immediate rewards and larger, delayed rewards. Their scores on the Perceived Stress Scale were also collected. The way in which one appraises a stressful situation interacts with acute stress to influence choices; under stressful conditions, delay discounting rate was highest in individuals with low perceived stress and lowest for individuals with high perceived stress. This result might be related to individual variation in reward responsiveness under stress. Furthermore, the time orientation of the task interacted with its stressfulness to affect the individual’s propensity to choose immediate rewards. These findings add to our understanding of the intermediary factors between stress and decision making.

  1. Discounting of money and sex: effects of commodity and temporal position in stimulant-dependent men and women.

    Science.gov (United States)

    Jarmolowicz, David P; Landes, Reid D; Christensen, Darren R; Jones, Bryan A; Jackson, Lisa; Yi, Richard; Bickel, Warren K

    2014-11-01

    Research on delay discounting has contributed to the understanding of numerous addiction-related phenomena. For example, studies have shown that substance dependent individuals discount their addictive substances (e.g., cocaine) more rapidly than they do other commodities (e.g., money). Recent research has shown that substance dependent individuals discount delayed sex more rapidly than delayed money, and their discounting rates for delayed sex were higher than those of non-addicted individuals. The particular reason that delay discounting rates for sex are higher than those for money, however, are unclear. Do individuals discount delayed sex rapidly because immediate sex is particularly appealing or because delayed sex does not retain its value? Moreover, do the same factors influence men and women's choices? The current study examined delay discounting in four conditions (money now versus money later; sex now versus sex later; money now, versus sex later; sex now versus money later) in cocaine dependent men and women. The procedures used isolated the role of the immediate versus delayed commodity. For men, the higher rates of delay discounting for sex were because delayed sex did not retain its value, whereas both the immediate and delayed commodity influenced the female participants' decisions. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Assessment method to predict the rate of unresolved false alarms

    International Nuclear Information System (INIS)

    Reardon, P.T.; Eggers, R.F.; Heaberlin, S.W.

    1982-06-01

    A method has been developed to predict the rate of unresolved false alarms of material loss in a nuclear facility. The computer program DETRES-1 was developed. The program first assigns the true values of control unit components receipts, shipments, beginning and ending inventories. A normal random number generator is used to generate measured values of each component. A loss estimator is calculated from the control unit's measured values. If the loss estimator triggers a detection alarm, a response is simulated. The response simulation is divided into two phases. The first phase is to simulate remeasurement of the components of the detection loss estimator using the same or better measurement methods or inferences from surrounding control units. If this phase of response continues to indicate a material loss, phase of response simulating a production shutdown and comprehensive cleanout is initiated. A new loss estimator is found, and tested against the alarm thresholds. If the estimator value is below the threshold, the original detection alarm is considered resolved; if above the threshold, an unresolved alarm has occurred. A tally is kept of valid alarms, unresolved false alarms, and failure to alarm upon a true loss

  3. ACCOUNTING TREATMENT FOR COMMERCIAL DISCOUNTS ON GOODS PURCHASED FOR RESALE

    Directory of Open Access Journals (Sweden)

    HOLT GHEORGHE

    2016-04-01

    Full Text Available In the specialized literature there are two major categories of discounts applied between business partners: trade discounts and financial discounts. In terms of accounting, the method of calculation of interest is commercial and financial cuts, especially the tax treatment of them. Trade discounts are applied prior to financial services, and both types of discounts are calculated on the net earlier. Discounts are calculated after applying discounts and special an issue is to know the level of rebates, which are determined periodically based on the turnover.

  4. Observed and Normative Discount Functions in Addiction and other Diseases

    OpenAIRE

    Cruz Rambaud, Salvador; Mu?oz Torrecillas, Mar?a J.; Takahashi, Taiki

    2017-01-01

    The aim of this paper is to find a suitable discount function able to describe the progression of a certain addiction or disease under treatment as a discounting process. In effect, a certain indicator related to a disease decays over time in a manner which is mathematically similar to the way in which discounting has been modeled. We analyze the discount functions observed in experiments which study addictive and other problematic behaviors as well as some alternative hyperbola-like discount...

  5. Intertemporal Decision Making After Brain Injury: Amount-Dependent Steeper Discounting after Frontal Cortex Damage

    Directory of Open Access Journals (Sweden)

    Białaszek Wojciech

    2017-12-01

    Full Text Available Traumatic brain injuries to the frontal lobes are associated with many maladaptive forms of behavior. We investigated the association between brain damage and impulsivity, as measured by the rate of delay discounting (i.e., the extent to which future outcomes are devalued in time. The main aim of this study was to test the hypothesis of steeper discounting of different amounts in a group of patients with frontal lobe damage. We used a delay discounting task in the form of a structured interview. A total of 117 participants were divided into five groups: three neurological groups and two groups without brain damage. Our analyses showed that patients with focal damage to the frontal lobes demonstrated steeper delay discounting than other participants. Other clinical groups demonstrated similar discounting rates. The data pattern related to the magnitude effect on the group level suggested that the magnitude effect is absent in the group of patients with damage to the frontal lobes; however, results were less consistent on an individual level. Amount-dependent discounting was observed in only two groups, the healthy control group and the neurological group with other cortical areas damaged.

  6. An SEU rate prediction method for microprocessors of space applications

    International Nuclear Information System (INIS)

    Gao Jie; Li Qiang

    2012-01-01

    In this article,the relationship between static SEU (Single Event Upset) rate and dynamic SEU rate in microprocessors for satellites is studied by using process duty cycle concept and fault injection technique. The results are compared to in-orbit flight monitoring data. The results show that dynamic SEU rate by using process duty cycle can estimate in-orbit SEU rate of microprocessor reasonable; and the fault injection technique is a workable method to estimate SEU rate. (authors)

  7. Discounting future health benefits: the poverty of consistency arguments.

    Science.gov (United States)

    Nord, Erik

    2011-01-01

    In economic evaluation of health care, main stream practice is to discount benefits at the same rate as costs. But main papers in which this practice is advocated have missed a distinction between two quite different evaluation problems: (1) How much does the time of program occurrence matter for value and (2) how much do delays in health benefits from programs implemented at a given time matter? The papers have furthermore focused on logical and arithmetic arguments rather than on real value considerations. These 'consistency arguments' are at best trivial, at worst logically flawed. At the end of the day, there is a sensible argument for equal discounting of costs and benefits rooted in microeconomic theory of rational, utility maximising consumers' saving behaviour. But even this argument is problematic, first because the model is not clearly supported by empirical observations of individuals' time preferences for health, second because it relates only to evaluation in terms of overall individual utility. It does not provide grounds for claiming that decision makers with a wider societal perspective, which may include concerns for fair distribution, need to discount Copyright © 2010 John Wiley & Sons, Ltd. 2010 John Wiley & Sons, Ltd.

  8. Retailer Stackelberg game in a supply chain with pricing and service decisions and simple price discount contract

    Science.gov (United States)

    Sadjadi, Seyed Jafar; Sadeghian, Ramin; Sahebi, Hadi

    2018-01-01

    This paper studies the Retailer Stackelberg game in a supply chain consisting of two manufacturers and one retailer where they compete simultaneously under three factors including price, service and simple price discount contract. It is assumed that the second manufacturer provides service directly to his customers, and the retailer provides service for the first product’s customers, while the retailer buys the first product under price discount from the first manufacturer. The analysis of the optimal equilibrium solutions and the results of the numerical examples show that if a manufacturer chooses the appropriate range of discount rate, he will gain more profit than when there is no discount given to the retailer. This situation can be considered as an effective tool for the coordination of the first manufacturer and the retailer to offer discount by manufacturer and to provide the service by the retailer. We obtain equilibrium solution of Retailer Stackelberg game and analyze the numerical examples under two cases: a) the manufacturers sell their products to the retailer without price discount contract. b) The first manufacturer sells his products to the retailer with the simple price discount contract. The preliminary results show that the service and the price discount contract can improve the performance of supply chain. PMID:29649315

  9. Retailer Stackelberg game in a supply chain with pricing and service decisions and simple price discount contract.

    Science.gov (United States)

    Sadjadi, Seyed Jafar; Asadi, Hashem; Sadeghian, Ramin; Sahebi, Hadi

    2018-01-01

    This paper studies the Retailer Stackelberg game in a supply chain consisting of two manufacturers and one retailer where they compete simultaneously under three factors including price, service and simple price discount contract. It is assumed that the second manufacturer provides service directly to his customers, and the retailer provides service for the first product's customers, while the retailer buys the first product under price discount from the first manufacturer. The analysis of the optimal equilibrium solutions and the results of the numerical examples show that if a manufacturer chooses the appropriate range of discount rate, he will gain more profit than when there is no discount given to the retailer. This situation can be considered as an effective tool for the coordination of the first manufacturer and the retailer to offer discount by manufacturer and to provide the service by the retailer. We obtain equilibrium solution of Retailer Stackelberg game and analyze the numerical examples under two cases: a) the manufacturers sell their products to the retailer without price discount contract. b) The first manufacturer sells his products to the retailer with the simple price discount contract. The preliminary results show that the service and the price discount contract can improve the performance of supply chain.

  10. A Smart Soft Sensor Predicting Feedwater Flow Rate

    International Nuclear Information System (INIS)

    Yang, Heon Young; Na, Man Gyun

    2009-01-01

    Since we evaluate thermal nuclear reactor power with secondary system calorimetric calculations based on feedwater flow rate measurements, we need to measure the feedwater flow rate accurately. The Venturi flow meters that are being used to measure the feedwater flow rate in most pressurized water reactors (PWRs) measure the flow rate by developing a differential pressure across a physical flow restriction. The differential pressure is then multiplied by a calibration factor that depends on various flow conditions in order to calculate the feedwater flow rate. The calibration factor is determined by the feedwater temperature and pressure. However, Venturi meters cause a buildup of corrosion products near the orifice of the meter. This fouling increases the measured pressure drop across the meter, thereby causing an overestimation of the feedwater flow rate

  11. Predicting Translation Initiation Rates for Designing Synthetic Biology

    International Nuclear Information System (INIS)

    Reeve, Benjamin; Hargest, Thomas; Gilbert, Charlie; Ellis, Tom

    2014-01-01

    In synthetic biology, precise control over protein expression is required in order to construct functional biological systems. A core principle of the synthetic biology approach is a model-guided design and based on the biological understanding of the process, models of prokaryotic protein production have been described. Translation initiation rate is a rate-limiting step in protein production from mRNA and is dependent on the sequence of the 5′-untranslated region and the start of the coding sequence. Translation rate calculators are programs that estimate protein translation rates based on the sequence of these regions of an mRNA, and as protein expression is proportional to the rate of translation initiation, such calculators have been shown to give good approximations of protein expression levels. In this review, three currently available translation rate calculators developed for synthetic biology are considered, with limitations and possible future progress discussed.

  12. Unpredictable After All? A short note on exchange rate predictability

    NARCIS (Netherlands)

    G.A. Moerman (Gerard)

    2001-01-01

    textabstractEarlier research has shown that it is very hard to outperform the random walk model with respect to forecasting exchange rates. In this paper we propose an extension to the regular regime-switching model in order to capture the exchange rate dynamics. The model is extended by including

  13. Unhealthy diets, obesity and time discounting: a systematic literature review and network analysis.

    Science.gov (United States)

    Barlow, Pepita; Reeves, Aaron; McKee, Martin; Galea, Gauden; Stuckler, David

    2016-09-01

    There is an increasing policy commitment to address the avoidable burdens of unhealthy diet, overweight and obesity. However, to design effective policies, it is important to understand why people make unhealthy dietary choices. Research from behavioural economics suggests a critical role for time discounting, which describes how people's value of a reward, such as better health, decreases with delay to its receipt. We systematically reviewed the literature on the relationship of time discounting with unhealthy diets, overweight and obesity in Web of Science and PubMed. We identified 41 studies that met our inclusion criteria as they examined the association between time discount rates and (i) unhealthy food consumption; (ii) overweight and (iii) response to dietary and weight loss interventions. Nineteen out of 25 cross-sectional studies found time discount rates positively associated with overweight, obesity and unhealthy diets. Experimental studies indicated that lower time discounting was associated with greater weight loss. Findings varied by how time discount rates were measured; stronger results were observed for food than monetary-based measurements. Network co-citation analysis revealed a concentration of research in nutrition journals. Overall, there is moderate evidence that high time discounting is a significant risk factor for unhealthy diets, overweight and obesity and may serve as an important target for intervention. © 2016 The Authors Obesity Reviews published by John Wiley & Sons Ltd on behalf of International Association for the Study of Obesity (IASO). © 2016 The Authors Obesity Reviews published by John Wiley & Sons Ltd on behalf of International Association for the Study of Obesity (IASO).

  14. 10% discount at Novae restaurants for students

    CERN Document Server

    2016-01-01

    A 10% discount will be granted for students dining in restaurants 1 and 2 (on the Meyrin site) during the summer from 15 June 2016 to 15 September 2016.   A special badge will be issued by the respective secretariats if the student fulfils the following criteria:  Is under 25 years old; Is in possession of a student card issued by a University or college; Has a CERN contract > 1 month (Users, Summer Students, Trainees, etc). This badge and the CERN access card will have to be shown at the Novae restaurants in order to benefit from this discount.

  15. Conversion Factors for Predicting Unshielded Dose Rates in Shielded Waste

    International Nuclear Information System (INIS)

    Clapham, M.; Seamans Jr, J.V.; Arbon, R.E.

    2009-01-01

    This document describes the methodology developed and used by the Advanced Mixed Waste Treatment Project for determining the activity content and the unshielded surface dose rate for lead lined containers contaminated with transuranic waste. Several methods were investigated: - Direct measurement of the dose rate after removing the shielding. - Use of a MicroShield R derived dose conversion factor, (mRem/hr unshielded )/(mRem/hr shielded ), applied to the measured surface dose rate to estimate the unshielded surface dose rate. - Use of a MicroShield R derived activity conversion factor, mRem/hr unshielded /Ci, applied to the measured activity to estimate the unshielded dose rate. - Use of an empirically derived activity conversion factor, mRem/hr unshielded /Ci, applied to the measured activity to estimate the unshielded dose rate. The last approach proved to be the most efficacious by using a combination of nondestructive assay and empirically defined dose rate conversion factors. Empirically derived conversion factors were found to be highly dependent upon the matrix of the waste. Use of conversion factors relied on activity values corrected to address the presence of a lead liner. (authors)

  16. Split credit ratings and the prediction of bank ratings in the Basel II environment

    OpenAIRE

    Barton, Amanda

    2006-01-01

    This thesis investigates two aspects of credit risk measurement in the context of Basel 11: The International Convergence of Capital Measurement and Capital Standards. The first is the problem arising when two credit rating agencies disagree over the rating assigned to an issuer and a split rating arises. The second area is the determination of internal credit rating models for use under the Internal ratings-based approach. This thesis presents a variety of bank rating modes for individual an...

  17. empirical model for predicting rate of biogas production

    African Journals Online (AJOL)

    users

    Rate of biogas production using cow manure as substrate was monitored in two laboratory scale ... Biogas is a Gas obtained by anaerobic ... A. A. Adamu, Petroleum and Natural Gas Processing Department, Petroleum Training Institute, P.M.B..

  18. Protein thermodynamics can be predicted directly from biological growth rates.

    Directory of Open Access Journals (Sweden)

    Ross Corkrey

    Full Text Available Life on Earth is capable of growing from temperatures well below freezing to above the boiling point of water, with some organisms preferring cooler and others hotter conditions. The growth rate of each organism ultimately depends on its intracellular chemical reactions. Here we show that a thermodynamic model based on a single, rate-limiting, enzyme-catalysed reaction accurately describes population growth rates in 230 diverse strains of unicellular and multicellular organisms. Collectively these represent all three domains of life, ranging from psychrophilic to hyperthermophilic, and including the highest temperature so far observed for growth (122 °C. The results provide credible estimates of thermodynamic properties of proteins and obtain, purely from organism intrinsic growth rate data, relationships between parameters previously identified experimentally, thus bridging a gap between biochemistry and whole organism biology. We find that growth rates of both unicellular and multicellular life forms can be described by the same temperature dependence model. The model results provide strong support for a single highly-conserved reaction present in the last universal common ancestor (LUCA. This is remarkable in that it means that the growth rate dependence on temperature of unicellular and multicellular life forms that evolved over geological time spans can be explained by the same model.

  19. Characterizing and predicting rates of delirium across general hospital settings.

    Science.gov (United States)

    McCoy, Thomas H; Hart, Kamber L; Perlis, Roy H

    2017-05-01

    To better understand variation in reported rates of delirium, this study characterized delirium occurrence rate by department of service and primary admitting diagnosis. Nine consecutive years (2005-2013) of general hospital admissions (N=831,348) were identified across two academic medical centers using electronic health records. The primary admitting diagnosis and the treating clinical department were used to calculate occurrence rates of a previously published delirium definition composed of billing codes and natural language processing of discharge summaries. Delirium rates varied significantly across both admitting diagnosis group (X 2 10 =12786, pdelirium (86/109764; 0.08%) and neurological admissions the greatest (2851/25450; 11.2%). Although the rate of delirium varied across the two hospitals the relative rates within departments (r=0.96, pdelirium varies significantly across admitting diagnosis and hospital department. Both admitting diagnosis and department of care are even stronger predictors of risk than age; as such, simple risk stratification may offer avenues for targeted prevention and treatment efforts. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Do illness rating systems predict discharge location, length of stay, and cost after total hip arthroplasty?

    Directory of Open Access Journals (Sweden)

    Sarah E. Rudasill, BA

    2018-06-01

    Conclusions: These findings suggest that although ASA classifications predict discharge location and SOI scores predict length of stay and total costs, other factors beyond illness rating systems remain stronger predictors of discharge for THA patients.

  1. Sex allocation predicts mating rate in a simultaneous hermaphrodite

    OpenAIRE

    Janicke, Tim; Schärer, Lukas

    2009-01-01

    Sexual selection theory for separate-sexed animals predicts that the sexes differ in the benefit they can obtain from multiple mating. Conventional sex roles assume that the relationship between the number of mates and the fitness of an individual is steeper in males compared with females. Under these conditions, males are expected to be more eager to mate, whereas females are expected to be choosier. Here we hypothesize that the sex allocation, i.e. the reproductive investment devoted to the...

  2. Predicted occurrence rate of severe transportation accidents involving large casks

    International Nuclear Information System (INIS)

    Dennis, A.W.

    1978-01-01

    A summary of the results of an investigation of the severities of highway and railroad accidents as they relate to the shipment of large radioactive materials casks is discussed. The accident environments considered are fire, impact, crash, immersion, and puncture. For each of these environments, the accident severities and their predicted frequencies of occurrence are presented. These accident environments are presented in tabular and graphic form to allow the reader to evaluate the probabilities of occurrence of the accident parameter severities he selects

  3. A behavioral economic analysis of texting while driving: Delay discounting processes.

    Science.gov (United States)

    Hayashi, Yusuke; Miller, Kimberly; Foreman, Anne M; Wirth, Oliver

    2016-12-01

    The purpose of the present study was to examine an impulsive decision-making process underlying texting while driving from a behavioral economic perspective. A sample of 108 college students completed a novel discounting task that presented participants with a hypothetical scenario in which, after receiving a text message while driving, they rated the likelihood of replying to a text message immediately versus waiting to reply for a specific period of time. Participants also completed a delay discounting task in which they made repeated hypothetical choices between obtaining a larger amount of money available after a delay and an equal or lesser amount of money available immediately. The results show that the duration of the delay is a critical variable that strongly determines whether participants choose to wait to reply to a text message, and that the decrease in the likelihood of waiting as a function of delay is best described by a hyperbolic delay discounting function. The results also show that participants who self-reported higher frequency of texting while driving discounted the opportunity to reply to a text message at greater rates, whereas there was no relation between the rates of discounting of hypothetical monetary rewards and the frequency of texting while driving. The results support the conclusion that texting while driving is fundamentally an impulsive choice. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. An adaptive, individualized fMRI delay discounting procedure to increase flexibility and optimize scanner time.

    Science.gov (United States)

    Koffarnus, Mikhail N; Deshpande, Harshawardhan U; Lisinski, Jonathan M; Eklund, Anders; Bickel, Warren K; LaConte, Stephen M

    2017-11-01

    Research on the rate at which people discount the value of future rewards has become increasingly prevalent as discount rate has been shown to be associated with many unhealthy patterns of behavior such as drug abuse, gambling, and overeating. fMRI research points to a fronto-parietal-limbic pathway that is active during decisions between smaller amounts of money now and larger amounts available after a delay. Researchers in this area have used different variants of delay discounting tasks and reported various contrasts between choice trials of different types from these tasks. For instance, researchers have compared 1) choices of delayed monetary amounts to choices of the immediate monetary amounts, 2) 'hard' choices made near one's point of indifference to 'easy' choices that require little thought, and 3) trials where an immediate choice is available versus trials where one is unavailable, regardless of actual eventual choice. These differences in procedure and analysis make comparison of results across studies difficult. In the present experiment, we designed a delay discounting task with the intended capability of being able to construct contrasts of all three comparisons listed above while optimizing scanning time to reduce costs and avoid participant fatigue. This was accomplished with an algorithm that customized the choice trials presented to each participant with the goal of equalizing choice trials of each type. We compared this task, which we refer to here as the individualized discounting task (IDT), to two other delay discounting tasks previously reported in the literature (McClure et al., 2004; Amlung et al., 2014) in 18 participants. Results show that the IDT can examine each of the three contrasts mentioned above, while yielding a similar degree of activation as the reference tasks. This suggests that this new task could be used in delay discounting fMRI studies to allow researchers to more easily compare their results to a majority of previous

  5. THE SECULAR INFLUENCE OF THE RATE OF REFERENCE ON THE ECONOMIC POLICIES

    OpenAIRE

    Emilian M.DOBRESCU

    2005-01-01

    Having as starting point Radu Stoenescu’s book with respect to discount, and the difficulty in defining discount, we pursue to clarify this category and other associated ones, such as reference rate, discount rate, re-discount and its rate, in a historical and actual approach. The purpose is to demonstrate that the monetary policy about discount influences the economic policies and that is why it must be altered and guided in accordance with the changes of current economic-financial activity.

  6. Discounts at the Carlson Wagonlit travel agency

    CERN Document Server

    2008-01-01

    The Carlson Wagonlit travel agency is offering exceptional discounts of up to 40% for bookings with M-Travel before 29 February 2008 and Helvetic Tours before 30 March 2008. For terms and conditions and further information please contact the CERN Carlson Wagonlit Travel office, Main Building (500), Tel. 72763.

  7. Discounted Markov games : generalized policy iteration method

    NARCIS (Netherlands)

    Wal, van der J.

    1978-01-01

    In this paper, we consider two-person zero-sum discounted Markov games with finite state and action spaces. We show that the Newton-Raphson or policy iteration method as presented by Pollats-chek and Avi-Itzhak does not necessarily converge, contradicting a proof of Rao, Chandrasekaran, and Nair.

  8. A Delay Discounting Model of Psychotherapy Termination

    Science.gov (United States)

    Swift, Joshua K.; Callahan, Jennifer L.

    2009-01-01

    Delay discounting (DD) procedures are emerging as an important new method for psychotherapy researchers. In this paper a framework for conceptualizing existing, seemingly discrepant, research findings on termination is introduced and new directions for research are described. To illustrate the value of a DD framework, the common psychotherapy…

  9. Win-Win Strategies at Discount Stores

    NARCIS (Netherlands)

    B. Deleersnyder (Barbara); M.G. Dekimpe (Marnik); J-B.E.M. Steenkamp (Jan-Benedict); O. Koll (Oliver)

    2005-01-01

    textabstractAn important development that contributes to store brands’ growing success in the grocery market is the increasing number of discount stores that sell predominantly own, private-label, brands. To fight private labels, manufacturers of national brands feel increasingly compelled to

  10. Book Discounts and Cost-Plus Pricing

    Science.gov (United States)

    Andresen, David C.

    1974-01-01

    The adoption of cost-plus pricing by a major book jobber may have profound effects on the discounts that libraries receive. The article explains the pricing system and presents a set of graphs for libraries to use to determine its effects. (Author)

  11. Error Discounting in Probabilistic Category Learning

    Science.gov (United States)

    Craig, Stewart; Lewandowsky, Stephan; Little, Daniel R.

    2011-01-01

    The assumption in some current theories of probabilistic categorization is that people gradually attenuate their learning in response to unavoidable error. However, existing evidence for this error discounting is sparse and open to alternative interpretations. We report 2 probabilistic-categorization experiments in which we investigated error…

  12. Predicting chromium (VI) adsorption rate in the treatment of liquid ...

    African Journals Online (AJOL)

    Administrator

    The adsorption rate of chromium (VI) on commercial activated carbon during the ... time and initial chromium (VI) ion concentration. .... model, the separation factor r, according to Calvo et al (2001) cited .... Lead (II) and nickel (II) adsorption kinetics .... heavy metal by Talaromyces helicus: a trained fungus for copper and.

  13. Predicting chromium (VI) adsorption rate in the treatment of liquid ...

    African Journals Online (AJOL)

    The adsorption rate of chromium (VI) on commercial activated carbon during the treatment of the flocculation effluent of liquid-phase oil-based drill-cuttings has been investigated in terms of contact time and initial chromium (VI) ion concentration. Homogenizing 1 g of the activated carbon with 100 ml of the flocculation ...

  14. Empirical Model for Predicting Rate of Biogas Production | Adamu ...

    African Journals Online (AJOL)

    Rate of biogas production using cow manure as substrate was monitored in two laboratory scale batch reactors (13 liter and 108 liter capacities). Two empirical models based on the Gompertz and the modified logistic equations were used to fit the experimental data based on non-linear regression analysis using Solver tool ...

  15. Measurement-theoretic foundations of time discounting in economics

    OpenAIRE

    Conrad Heilmann

    2008-01-01

    In economics, the concept of time discounting introduces weights on future goods to make these less valuable. Yet, both the conceptual motivation for time discounting and its specic functional form remain contested. To address these problems, this paper provides a measurement-theoretic framework of representation for time discounting. The representation theorem characterises time discounting factors by representations of time dierences. This general result can be interpreted with existing the...

  16. Do the Powerful Discount the Future Less? The Effects of Power on Temporal Discounting.

    Science.gov (United States)

    Duan, Jinyun; Wu, Sherry J; Sun, Luying

    2017-01-01

    Individuals have the tendency to discount rewards in the future, known as temporal discounting, and we find that sense of power (the felt capacity to influence the thinking and behavior of others) reduces such tendency. In Studies 1 and 2, we used both an experiment and a survey with organizational employees to demonstrate that power reduced temporal discounting. In Study 3, we replicated study 1 while exploring a unique cultural trait of Danbo , or indifference to fame and wealth, across two ethnic groups (Han and Tibetan groups) in China. While power reduces temporal discounting, the relationship between the two may be leveraged by individual differences of optimism, frustration, and Danbo . The results imply a more nuanced interpretation of how individual and situational factors can affect intertemporal choice.

  17. Rate Predictions and Trigger/DAQ Resource Monitoring in ATLAS

    CERN Document Server

    Schaefer, D M; The ATLAS collaboration

    2012-01-01

    Since starting in 2010, the Large Hadron Collider (LHC) has pro- duced collisions at an ever increasing rate. The ATLAS experiment successfully records the collision data with high eciency and excel- lent data quality. Events are selected using a three-level trigger system, where each level makes a more re ned selection. The level-1 trigger (L1) consists of a custom-designed hardware trigger which seeds two higher software based trigger levels. Over 300 triggers compose a trig- ger menu which selects physics signatures such as electrons, muons, particle jets, etc. Each trigger consumes computing resources of the ATLAS trigger system and oine storage. The LHC instantaneous luminosity conditions, desired physics goals of the collaboration, and the limits of the trigger infrastructure determine the composition of the ATLAS trigger menu. We describe a trigger monitoring frame- work for computing the costs of individual trigger algorithms such as data request rates and CPU consumption. This framework has been used...

  18. Destination discount : A sensible road for national brands?

    NARCIS (Netherlands)

    Deleersnyder, B.; Koll, O.

    2012-01-01

    Purpose – This paper aims to study the consequences of listing national brands in discounters. Is the discount channel a promising outlet for manufacturer brands? Is it an effective means to attract new buyers? Which combination of brand and discount destination at which price is best suited for

  19. Discount-Optimal Infinite Runs in Priced Timed Automata

    DEFF Research Database (Denmark)

    Fahrenberg, Uli; Larsen, Kim Guldstrand

    2009-01-01

    We introduce a new discounting semantics for priced timed automata. Discounting provides a way to model optimal-cost problems for infinite traces and has applications in optimal scheduling and other areas. In the discounting semantics, prices decrease exponentially, so that the contribution...

  20. 48 CFR 952.251-70 - Contractor employee travel discounts.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Contractor employee travel... Contractor employee travel discounts. As prescribed in 951.7002, insert the following clause: Contractor Employee Travel Discounts (AUG 2009) (a) The Contractor shall take advantage of travel discounts offered to...

  1. 7 CFR 1786.98 - Discounted present value.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 12 2010-01-01 2010-01-01 false Discounted present value. 1786.98 Section 1786.98... Discounted present value. (a) The Discounted Present Value shall be calculated by RUS before prepayment is made by summing the present values of all remaining payments on all outstanding notes according to the...

  2. Rating the Quality of Open Textbooks: How Reviewer and Text Characteristics Predict Ratings

    Science.gov (United States)

    Fischer, Lane; Ernst, David; Mason, Stacie

    2017-01-01

    Using data collected from peer reviews for Open Textbook Library titles, this paper explores questions about rating the quality of open textbooks. The five research questions addressed the relationship between textbook and reviewer characteristics and ratings. Although reviewers gave textbooks high ratings generally, reviewers identified…

  3. Empirical correlation for prediction of the elutriation rate constant

    Directory of Open Access Journals (Sweden)

    Stojkovski Valentino

    2003-01-01

    Full Text Available In vessels containing fluidized solids, the gas leaving carries some suspended particles. This flux of solids is called entrainment, E or carryover and the bulk density of solids on this leaving gas stream is called the holdup. For design we need to know the rate of this entrainment and the size distribution of these entrained particles Rim in relation to the size distribution in the bed, Rib, as well as the variation of both these quantities with gas and solids properties, gas flow rate, bed geometry and location of the leaving gas stream. Steady-state elutriation experiments have been done in a fluidized bed 0,2 m diameter by 2,94 m high freeboard with superficial gas velocities up to 1 m/s using solids ranging in mean size from 0,15 to 0,58 mm and with particle density 2660 kg/m3. When the fine and coarse particles were mixed, the total entrainment flux above the freeboard was increased. None of the published correlations for estimating the elutriation rate constant were useful. A new simple equation, which is developed on the base of experimental results and theory of dimensional analyses, is presented.

  4. Discounting and distributional considerations in the context of global warming

    International Nuclear Information System (INIS)

    Azar, Christian; Sterner, Thomas

    1996-01-01

    The economics of global warming is reviewed with special emphasis on how the cost depends on the discount rate and on how costs in poor and rich regions are aggregated into a global cost estimate. Both of these factors depend on the assumptions made concerning the underlying utility and welfare functions. It is common to aggregate welfare gains and losses across generations and countries as if the utility of money were constant, but it is not. If we assume that a CO 2 -equivalent doubling implies costs equal to 1.5% of the income in both high and low income countries, a pure rate of time preference equal to zero, and a utility function which is logarithmic in income, then the marginal cost of CO 2 emissions is estimated at 260-590 USD/ton C for a time horizon in the range 300-1000 years, an estimate which is large enough to justify significant reductions of CO 2 emissions on purely economic grounds. The estimate is approximately 50-100-times larger than the estimate made by Nordhaus in his DICE model and the difference is almost completely due to the choice of discount rate and the weight given to the costs in the developing world as well as a more accurate model of the carbon cycle. Finally, the sensitivity of the marginal cost estimate with respect to several parameters is analyzed

  5. Does basal metabolic rate predict weight gain?12

    Science.gov (United States)

    Anthanont, Pimjai; Jensen, Michael D

    2016-01-01

    Background: Some previous studies have indicated that a low basal metabolic rate (BMR) is an independent predictor of future weight gain, but low rates of follow-up and highly select populations may limit the ability to generalize the results. Objective: We assessed whether adults with a low BMR gain more weight than do adults with a high BMR who are living in a typical Western environment. Design: We extracted BMR, body-composition, demographic, and laboratory data from electronic databases of 757 volunteers who were participating in our research protocols at the Mayo Clinic between 1995 and 2012. Research study volunteers were always weight stable, had no acute illnesses and no confounding medication use, and were nonsmokers. The top and bottom 15th percentiles of BMR, adjusted for fat-free mass (FFM), fat mass, age, and sex, were identified. Follow-up electronic medical record system data were available for 163 subjects, which allowed us to determine their subsequent weight changes for ≥3 y (mean: ∼9.7 y). Results: By definition, the BMR was different in the high-BMR group (2001 ± 317 kcal/d; n = 86) than in the low-BMR group (1510 ± 222 kcal/d; n = 77), but they were comparable with respect to age, body mass index, FFM, and fat mass. Rates of weight gain were not greater in the bottom BMR group (0.3 ± 1.0 kg/y) than in the top BMR group (0.5 ± 1.5 kg/y) (P = 0.17). Conclusion: Adults with low BMRs did not gain more weight than did adults with high BMRs, implying that habitual differences in food intake or activity counterbalance variations in BMR as a risk factor for weight gain in a typical Western population. PMID:27581474

  6. Discounting and decision making in the economic evaluation of health-care technologies.

    Science.gov (United States)

    Claxton, Karl; Paulden, Mike; Gravelle, Hugh; Brouwer, Werner; Culyer, Anthony J

    2011-01-01

    Discounting costs and health benefits in cost-effectiveness analysis has been the subject of recent debate - some authors suggesting a common rate for both and others suggesting a lower rate for health. We show how these views turn on key judgments of fact and value: on whether the social objective is to maximise discounted health outcomes or the present consumption value of health; on whether the budget for health care is fixed; on the expected growth in the cost-effectiveness threshold; and on the expected growth in the consumption value of health. We demonstrate that if the budget for health care is fixed and decisions are based on incremental cost effectiveness ratios (ICERs), discounting costs and health gains at the same rate is correct only if the threshold remains constant. Expecting growth in the consumption value of health does not itself justify differential rates but implies a lower rate for both. However, whether one believes that the objective should be the maximisation of the present value of health or the present consumption value of health, adopting the social time preference rate for consumption as the discount rate for costs and health gains is valid only under strong and implausible assumptions about values and facts. 2010 John Wiley & Sons, Ltd.

  7. Probabilistic Discounting of Hypothetical Monetary Gains: University Students Differ in How They Discount "Won" and "Owed" Money

    Science.gov (United States)

    Weatherly, Jeffrey N.; Derenne, Adam

    2013-01-01

    The present study tested whether participants would discount "won" money differently than they would "owed" money in a probability-discounting task. Participants discounted $1000 or $100,000 that they had won in a sweepstakes or that was owed to them using the multiple-choice (Experiment 1) or fill-in-the-blank (Experiment 2) method of collecting…

  8. Age of acquisition predicts rate of lexical evolution.

    Science.gov (United States)

    Monaghan, Padraic

    2014-12-01

    The processes taking place during language acquisition are proposed to influence language evolution. However, evidence demonstrating the link between language learning and language evolution is, at best, indirect, constituting studies of laboratory-based artificial language learning studies or computational simulations of diachronic change. In the current study, a direct link between acquisition and evolution is established, showing that for two hundred fundamental vocabulary items, the age at which words are acquired is a predictor of the rate at which they have changed in studies of language evolution. Early-acquired words are more salient and easier to process than late-acquired words, and these early-acquired words are also more stably represented within the community's language. Analysing the properties of these early-acquired words potentially provides insight into the origins of communication, highlighting features of words that have been ultra-conserved in language. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Prediction of Mass Flow Rate in Supersonic Natural Gas Processing

    Directory of Open Access Journals (Sweden)

    Wen Chuang

    2015-11-01

    Full Text Available The mass flow rate of natural gas through the supersonic separator was numerically calculated by various cubic equations of state. The numerical results show that the compressibility factor and specific heat ratio for ideal gas law diverge remarkably from real gas models at a high inlet pressure. Simultaneously, the deviation of mass flow calculated by the ideal and real gas models reaches over 10 %. The difference increases with the lower of the inlet temperature regardless of the inlet pressure. A higher back pressure results in an earlier location of the shock wave. The pressure ratio of 0.72 is the first threshold to get the separator work normally. The second threshold is 0.95, in which case the whole flow is subsonic and cannot reach the choked state. The shock position moves upstream with the real gas model compared to the ideal gas law in the cyclonic separation section.

  10. Attention-deficit/hyperactivity disorder, delay discounting, and risky financial behaviors: A preliminary analysis of self-report data.

    Directory of Open Access Journals (Sweden)

    Theodore P Beauchaine

    Full Text Available Delay discounting-often referred to as hyperbolic discounting in the financial literature-is defined by a consistent preference for smaller, immediate rewards over larger, delayed rewards, and by failure of future consequences to curtail current consummatory behaviors. Previous research demonstrates (1 excessive delay discounting among individuals with attention-deficit/hyperactivity disorder (ADHD, (2 common neural substrates of delay discounting and hyperactive-impulsive symptoms of ADHD, and (3 associations between delay discounting and both debt burden and high interest rate borrowing. This study extends prior research by examining associations between ADHD symptoms, delay discounting, and an array of previously unevaluated financial outcomes among 544 individuals (mean age 35 years. Controlling for age, income, sex, education, and substance use, ADHD symptoms were associated with delay discounting, late credit card payments, credit card balances, use of pawn services, personal debt, and employment histories (less time spent at more jobs. Consistent with neural models of reward processing and associative learning, more of these relations were attributable to hyperactive-impulsive symptoms than inattentive symptoms. Implications for financial decision-making and directions for future research are discussed.

  11. Attention-deficit/hyperactivity disorder, delay discounting, and risky financial behaviors: A preliminary analysis of self-report data.

    Science.gov (United States)

    Beauchaine, Theodore P; Ben-David, Itzhak; Sela, Aner

    2017-01-01

    Delay discounting-often referred to as hyperbolic discounting in the financial literature-is defined by a consistent preference for smaller, immediate rewards over larger, delayed rewards, and by failure of future consequences to curtail current consummatory behaviors. Previous research demonstrates (1) excessive delay discounting among individuals with attention-deficit/hyperactivity disorder (ADHD), (2) common neural substrates of delay discounting and hyperactive-impulsive symptoms of ADHD, and (3) associations between delay discounting and both debt burden and high interest rate borrowing. This study extends prior research by examining associations between ADHD symptoms, delay discounting, and an array of previously unevaluated financial outcomes among 544 individuals (mean age 35 years). Controlling for age, income, sex, education, and substance use, ADHD symptoms were associated with delay discounting, late credit card payments, credit card balances, use of pawn services, personal debt, and employment histories (less time spent at more jobs). Consistent with neural models of reward processing and associative learning, more of these relations were attributable to hyperactive-impulsive symptoms than inattentive symptoms. Implications for financial decision-making and directions for future research are discussed.

  12. An Electrochemical Method to Predict Corrosion Rates in Soils

    Energy Technology Data Exchange (ETDEWEB)

    Dafter, M. R. [Hunter Water Australia Pty Ltd, Newcastle (Australia)

    2016-10-15

    Linear polarization resistance (LPR) testing of soils has been used extensively by a number of water utilities across Australia for many years now to determine the condition of buried ferrous water mains. The LPR test itself is a relatively simple, inexpensive test that serves as a substitute for actual exhumation and physical inspection of buried water mains to determine corrosion losses. LPR testing results (and the corresponding pit depth estimates) in combination with proprietary pipe failure algorithms can provide a useful predictive tool in determining the current and future conditions of an asset{sup 1)}. A number of LPR tests have been developed on soil by various researchers over the years{sup 1)}, but few have gained widespread commercial use, partly due to the difficulty in replicating the results. This author developed an electrochemical cell that was suitable for LPR soil testing and utilized this cell to test a series of soil samples obtained through an extensive program of field exhumations. The objective of this testing was to examine the relationship between short-term electrochemical testing and long-term in-situ corrosion of buried water mains, utilizing an LPR test that could be robustly replicated. Forty-one soil samples and related corrosion data were obtained from ad hoc condition assessments of buried water mains located throughout the Hunter region of New South Wales, Australia. Each sample was subjected to the electrochemical test developed by the author, and the resulting polarization data were compared with long-term pitting data obtained from each water main. The results of this testing program enabled the author to undertake a comprehensive review of the LPR technique as it is applied to soils and to examine whether correlations can be made between LPR testing results and long-term field corrosion.

  13. Patient-rated health status predicts prognosis following percutaneous coronary intervention with drug-eluting stenting

    DEFF Research Database (Denmark)

    Pedersen, Susanne S.; Versteeg, Henneke; Denollet, Johan

    2011-01-01

    In patients treated with percutaneous coronary intervention (PCI) with the paclitaxel-eluting stent, we examined whether patient-rated health status predicts adverse clinical events.......In patients treated with percutaneous coronary intervention (PCI) with the paclitaxel-eluting stent, we examined whether patient-rated health status predicts adverse clinical events....

  14. On the expected discounted penalty functions for two classes of risk processes under a threshold dividend strategy

    Science.gov (United States)

    Lu, Zhaoyang; Xu, Wei; Sun, Decai; Han, Weiguo

    2009-10-01

    In this paper, the discounted penalty (Gerber-Shiu) functions for a risk model involving two independent classes of insurance risks under a threshold dividend strategy are developed. We also assume that the two claim number processes are independent Poisson and generalized Erlang (2) processes, respectively. When the surplus is above this threshold level, dividends are paid at a constant rate that does not exceed the premium rate. Two systems of integro-differential equations for discounted penalty functions are derived, based on whether the surplus is above this threshold level. Laplace transformations of the discounted penalty functions when the surplus is below the threshold level are obtained. And we also derive a system of renewal equations satisfied by the discounted penalty function with initial surplus above the threshold strategy via the Dickson-Hipp operator. Finally, analytical solutions of the two systems of integro-differential equations are presented.

  15. Failure Rate Prediction of Active Component Using PM Basis Database

    International Nuclear Information System (INIS)

    Kim, J. S.; Kim, H. W.; Park, J. S.; Jung, S. G.

    2011-01-01

    The safety security and efficient management of NPPs (Nuclear Power Plants) have been increased after the accident of TEPCO's Fukushima nuclear power stations. The needs for the safety and efficiency are becoming more important because about 90 percent of the NPPs all over the world are more than 20 operation years old. The preventive maintenance criteria need to be flexible, considering long-term development of the equipment performance and preventive maintenance. The PMBD (Preventive Maintenance Basis Database) program was widely used for optimization of the preventive maintenance criteria. PMBD program contains all kinds of failure mechanisms for each equipment that may occur in the power plant based on RCM(Reliability-Centered Maintenance) and numerically calculate the variation of reliability and failure rate based on PM interval changes. In this study, propriety evaluation of preventive maintenance task, cycle, technical basis for cost effective preventive maintenance strategy and an appropriate evaluation were suggested by the case application of PMBD for major components in the NPPs

  16. Exchange rates and individual good's price misalignment: Some preliminary evidence of long-horizon predictability

    OpenAIRE

    Dong, Wei; Nam, Deokwoo

    2011-01-01

    When prices are sticky, movements in the nominal exchange rate have a direct impact on international relative prices. A relative price misalignment would trigger an adjustment in consumption and employment, and may help to predict future movements in the exchange rate. Although purchasing-power-parity fundamentals, in general, have only weak predictability, currency misalignment may be indicated by price differentials for some goods, which could then have predictive power for subsequent re-ev...

  17. Delay Discounting: Pigeon, Rat, Human – Does it Matter?

    Science.gov (United States)

    Vanderveldt, Ariana; Oliveira, Luís; Green, Leonard

    2016-01-01

    Delay discounting refers to the decrease in subjective value of an outcome as the time to its receipt increases. Across species and situations, animals discount delayed rewards, and their discounting is well-described by a hyperboloid function. The current review begins with a comparison of discounting models and the procedures used to assess delay discounting in nonhuman animals. We next discuss the generality of discounting, reviewing the effects of different variables on the degree of discounting delayed reinforcers by nonhuman animals. Despite the many similarities in discounting observed between human and nonhuman animals, several differences have been proposed (e.g., the magnitude effect; nonhuman animals discount over a matter of seconds whereas humans report willing to wait months, if not years before receiving a reward), raising the possibility of fundamental species differences in intertemporal choice. After evaluating these differences, we discuss delay discounting from an adaptationist perspective. The pervasiveness of discounting across species and situations suggests it is a fundamental process underlying decision making. PMID:26881899

  18. Particle deposition from aqueous suspensions in turbulent pipe flow - a comparison of observed deposition rates and predicted arrival rates

    International Nuclear Information System (INIS)

    Rodliffe, R.S.

    1979-11-01

    At the present time, there appear to be only four adequately controlled and characterised experimental studies of particle deposition from single phase water in turbulent pipe flow. These are used to illustrate the ranges of applicability of methods for predicting particle arrival rates at tube walls. Arrival rates are predicted from mass transfer correlations and the theory of Reeks and Skyrme (1976) when transport is limited by Brownian diffusion and inertial behaviour, respectively. The regimes in which finite particle size limits the application of these methods are defined and preliminary consideration is given to the conditions under which gravitational settling may make a contribution to deposition in vertically mounted tubes. (author)

  19. An alternative approach to calculating Area-Under-the-Curve (AUC) in delay discounting research.

    Science.gov (United States)

    Borges, Allison M; Kuang, Jinyi; Milhorn, Hannah; Yi, Richard

    2016-09-01

    Applied to delay discounting data, Area-Under-the-Curve (AUC) provides an atheoretical index of the rate of delay discounting. The conventional method of calculating AUC, by summing the areas of the trapezoids formed by successive delay-indifference point pairings, does not account for the fact that most delay discounting tasks scale delay pseudoexponentially, that is, time intervals between delays typically get larger as delays get longer. This results in a disproportionate contribution of indifference points at long delays to the total AUC, with minimal contribution from indifference points at short delays. We propose two modifications that correct for this imbalance via a base-10 logarithmic transformation and an ordinal scaling transformation of delays. These newly proposed indices of discounting, AUClog d and AUCor d, address the limitation of AUC while preserving a primary strength (remaining atheoretical). Re-examination of previously published data provides empirical support for both AUClog d and AUCor d . Thus, we believe theoretical and empirical arguments favor these methods as the preferred atheoretical indices of delay discounting. © 2016 Society for the Experimental Analysis of Behavior.

  20. Reliability of the Discounting Inventory: An extension into substance-use population

    Directory of Open Access Journals (Sweden)

    Malesza Marta

    2017-06-01

    Full Text Available Recent research introduced the Discounting Inventory that allows the measurement of individual differences in the delay, probabilistic, effort, and social discounting rates. The goal of this investigation was to determine several aspects of the reliability of the Discounting Inventory using the responses of 385 participants (200 non-smokers and 185 current-smokers. Two types of reliability are of interest. Internal consistency and test-retest stability. A secondary aim was to extend such reliability measures beyond the non-clinical participant. The current study aimed to measure the reliability of the DI in a nicotine-dependent individuals and non-nicotine-dependent individuals. It is concluded that the internal consistency of the DI is excellent, and that the test-retest reliability results suggest that items intended to measure three types of discounting were likely testing trait, rather than state, factors, regardless of whether “non-smokers” were included in, or excluded from, the analyses (probabilistic discounting scale scores being the exception. With these cautions in mind, however, the psychometric properties of the DI appear to be very good.

  1. Discount method for programming language evaluation

    DEFF Research Database (Denmark)

    Kurtev, Svetomir; Christensen, Tommy Aagaard; Thomsen, Bent

    2016-01-01

    This paper presents work in progress on developing a Discount Method for Programming Language Evaluation inspired by the Discount Usability Evaluation method (Benyon 2010) and the Instant Data Analysis method (Kjeldskov et al. 2004). The method is intended to bridge the gap between small scale...... internal language design evaluation methods and large scale surveys and quantitative evaluation methods. The method is designed to be applicable even before a compiler or IDE is developed for a new language. To test the method, a usability evaluation experiment was carried out on the Quorum programming...... language (Stefik et al. 2016) using programmers with experience in C and C#. When comparing our results with previous studies of Quorum, most of the data was comparable though not strictly in agreement. However, the discrepancies were mainly related to the programmers pre-existing expectations...

  2. Accounting and Tax Issues Concerning Commercial Discounts

    Directory of Open Access Journals (Sweden)

    Sava Raluca

    2015-12-01

    Full Text Available Commercial discounts accounting presents a particular importance because, on the one hand, of their widely spread on a large scale in the commercial activity and on the second hand, due to the influence of the accounting and reporting method over the value added tax. The paper theoretically addresses commercial reductions and also their reflection in the accounting according with the latest regulations in force.

  3. Introducing Upfront Money Can Decrease Discounting in Intertemporal Choices with Losses.

    Science.gov (United States)

    Jiang, Cheng-Ming; Sun, Hong-Yue; Zheng, Sheng-Hua; Wang, Liang-Jun; Qin, Yu

    2016-01-01

    People generally tend to advance gains and postpone losses in intertemporal choice. Jiang et al. (2014) recently showed that adding upfront losses or gains to both smaller and sooner (SS) and larger and later (LL) rewards can decrease people's discounting. To account for this decrease, they proposed the salience hypothesis, which states that introducing upfront losses or gains makes the money dimension more salient than not, thus increasing people's preference for LL rewards. Considering that decreasing the discounting of delayed losses is imperative and that most previous studies have focused on intertemporal choices with gains, in the current paper we conducted two experiments and used hypothetical money outcomes to examine whether the effect of upfront money could be extended to intertemporal choices with losses. The results showed that when both SS and LL intertemporal losses were combined with an upfront loss or gain, people's discounting rate decreased and the preference for the SS option increased. This finding further supports the salience account.

  4. Episodic Future Thinking about the Ideal Self Induces Lower Discounting, Leading to a Decreased Tendency toward Cheating.

    Science.gov (United States)

    Wu, Wen-Hsiung; Cheng, Wen; Chiou, Wen-Bin

    2017-01-01

    Delay discounting refers to a pervasive tendency toward preferring smaller immediate gains over larger future gains. Recent empirical research has shown that episodic future thinking (EFT; i.e., projecting oneself into the future to pre-experience forthcoming events) can reduce the tendency toward discounting. A common tenet of psychological theories of crime is that delinquency results from focusing on short-term gains while failing to consider adequately the longer-term consequences of delinquent behavior. We investigated whether an EFT intervention involving the ideal self could induce lower discounting rates and, as a consequence, reduced delinquency. The results showed that, compared with control participants, participants engaging in EFT, that is, envisaging life events that would be experienced by their ideal selves, exhibited a lower discounting rate in a monetary choice task (Experiments 1 and 2), as well as a decreased tendency to make delinquent choices in imaginary scenarios (Experiment 1) and cheat in a matrix task (Experiment 2). The discounting tendency mediated the relationship between engaging in EFT pertaining to the ideal self and the tendency toward morally questionable behavior (Experiments 1 and 2). The findings of the two experiments indicate that engagement in EFT with a focus on the ideal self is sufficient to induce lower discounting rates, by promoting consideration of distant costs and thus increasing resistance to delinquent involvement and cheating (given the temptation of the immediate benefits that may accrue from such behavior). The current research constitutes an innovative approach to delinquency prevention and the promotion of morality.

  5. Activity in dlPFC and its effective connectivity to vmPFC are associated with temporal discounting

    Directory of Open Access Journals (Sweden)

    Todd A Hare

    2014-03-01

    Full Text Available There is widespread interest in identifying computational and neurobiological mechanisms that influence the ability to choose long-term benefits over more proximal and readily available rewards in domains such as dietary and economic choice. We present the results of a human fMRI study that examines how neural activity relates to observed individual differences in the discounting of future rewards during an intertemporal monetary choice task. We found that a region of left dlPFC BA-46 was more active in trials where subjects chose delayed rewards, after controlling for the subjective value of those rewards. We also found that the connectivity from dlPFC BA-46 to a region of vmPFC widely associated with the computational of stimulus values, increased at the time of choice, and especially during trials in which subjects chose delayed rewards. Finally, we found that estimates of effective connectivity between these two regions played a critical role in predicting out-of-sample, between-subject differences in discount rates. Together with previous findings in dietary choice, these results suggest that a common set of computational and neurobiological mechanisms facilitate choices in favor of long- term reward in both settings.

  6. A Comparison of the Predicted Tube Plugging Rate for Alloy 600HTMA Steam Generator

    Energy Technology Data Exchange (ETDEWEB)

    Boo, Myung Hwan; Kang, Yong Seok [Korea Hydro and Nuclear Power Co., Daejeon (Korea, Republic of)

    2010-10-15

    To manage components that are used in long term operations such as steam generation, it is important to know the tube plugging rate, which can cause the performance degradation. The life of components can be predicted by the method using determinism and probability theory. With a method using probability theory, damage prediction of tube is possible. In this study, damage prediction for steam generation (SG) tube is performed using Weibull distribution and predicted plugging rate (life) is compared with the simple sum plugging number and case by case (failure cause) plugging number

  7. Delay discounting, impulsiveness, and addiction severity in opioid-dependent patients.

    Science.gov (United States)

    Robles, Elias; Huang, B Emma; Simpson, Pippa M; McMillan, Donald E

    2011-12-01

    Individuals who abuse drugs show higher delay discounting (DD) rate and impulsiveness scores compared with controls; however, it is unclear if DD rate covaries with severity of the addiction or if an individual's discounting rate can be changed by effective substance abuse treatment. This study compared methadone maintenance treatment (MMT) patients (n = 30) who had not used illegal drugs for 2 years with drug-using MMT patients (n = 30) and controls (n = 25) in terms of addiction severity, DD rate, and impulsiveness. Methadone patients abstinent from illegal drugs scored significantly lower on a number of addiction severity measures than the drug-using methadone patients. In addition, both groups of MMT patients showed significantly higher rates of DD and impulsiveness than the control group; however, no differences in DD rate or impulsiveness were found between the groups of patients. Results suggest that DD rate and impulsiveness may not covary with indicators of addiction severity in MMT patients. Published by Elsevier Inc.

  8. Predicting prey population dynamics from kill rate, predation rate and predator-prey ratios in three wolf-ungulate systems.

    Science.gov (United States)

    Vucetich, John A; Hebblewhite, Mark; Smith, Douglas W; Peterson, Rolf O

    2011-11-01

    1. Predation rate (PR) and kill rate are both fundamental statistics for understanding predation. However, relatively little is known about how these statistics relate to one another and how they relate to prey population dynamics. We assess these relationships across three systems where wolf-prey dynamics have been observed for 41 years (Isle Royale), 19 years (Banff) and 12 years (Yellowstone). 2. To provide context for this empirical assessment, we developed theoretical predictions of the relationship between kill rate and PR under a broad range of predator-prey models including predator-dependent, ratio-dependent and Lotka-Volterra dynamics. 3. The theoretical predictions indicate that kill rate can be related to PR in a variety of diverse ways (e.g. positive, negative, unrelated) that depend on the nature of predator-prey dynamics (e.g. structure of the functional response). These simulations also suggested that the ratio of predator-to-prey is a good predictor of prey growth rate. That result motivated us to assess the empirical relationship between the ratio and prey growth rate for each of the three study sites. 4. The empirical relationships indicate that PR is not well predicted by kill rate, but is better predicted by the ratio of predator-to-prey. Kill rate is also a poor predictor of prey growth rate. However, PR and ratio of predator-to-prey each explained significant portions of variation in prey growth rate for two of the three study sites. 5. Our analyses offer two general insights. First, Isle Royale, Banff and Yellowstone are similar insomuch as they all include wolves preying on large ungulates. However, they also differ in species diversity of predator and prey communities, exploitation by humans and the role of dispersal. Even with the benefit of our analysis, it remains difficult to judge whether to be more impressed by the similarities or differences. This difficulty nicely illustrates a fundamental property of ecological

  9. Drinking status but not acute alcohol consumption influences delay discounting.

    Science.gov (United States)

    Adams, Sally; Attwood, Angela S; Munafò, Marcus R

    2017-09-01

    The aim of this study was to investigate the following: (a) the effects of acute alcohol on delay discounting; (b) the effects of drinking status on delayed discounting; and (c) whether these effects differ according to reward type (alcohol vs. money). Heavy and light social alcohol users (n = 96) were randomized to receive either an acute dose of alcohol at 0.4 or 0.6 g/kg or placebo in a between-subjects, double-blind design. Delay discounting of alcohol and monetary rewards was measured using a hyperbolic model, with higher scores indicative of greater delay discounting. ANOVA of discount scores indicated a main effect of reward type, where all participants had higher discount scores for alcohol versus money rewards. A main effect of drinking status was also observed, where heavier drinkers had higher discount scores compared with lighter drinkers. We did not observe a main effect of acute alcohol use on delay discounting or the hypothesized interactions between acute alcohol use and drinking status with reward type. Our data suggest that heavier drinkers discount the value of delayed rewards more steeply than lighter drinkers. Delay discounting may therefore be a promising marker of heavy alcohol consumption in social drinkers. Copyright © 2017 John Wiley & Sons, Ltd.

  10. ATLAS trigger operations: Monitoring with “Xmon” rate prediction system

    CERN Document Server

    Aukerman, Andrew Todd; The ATLAS collaboration

    2017-01-01

    We present the operations and online monitoring with the “Xmon” rate prediction system for the trigger system at the ATLAS Experiment. A two-level trigger system reduces the LHC’s bunch-crossing rate, 40 MHz at design capacity, to an average recording rate of about 1 kHz, while maintaining a high efficiency of selecting events of interest. The Xmon system uses the luminosity value to predict trigger rates that are, in turn, compared with incoming rates. The predictions rely on past runs to parameterize the luminosity dependency of the event rate for a trigger algorithm. Some examples are given to illustrate the performance of the tool during recent operations.

  11. Heroin delay discounting: Modulation by pharmacological state, drug-use impulsivity, and intelligence.

    Science.gov (United States)

    Stoltman, Jonathan J K; Woodcock, Eric A; Lister, Jamey J; Lundahl, Leslie H; Greenwald, Mark K

    2015-12-01

    Delay discounting (DD) refers to how rapidly an individual devalues goods based on delays to receipt. DD usually is considered a trait variable but can be state dependent, yet few studies have assessed commodity valuation at short, naturalistically relevant time intervals that might enable state-dependent analysis. This study aimed to determine whether drug-use impulsivity and intelligence influence heroin DD at short (ecologically relevant) delays during two pharmacological states (heroin satiation and withdrawal). Out-of-treatment, intensive heroin users (n = 170; 53.5% African American; 66.7% male) provided complete DD data during imagined heroin satiation and withdrawal. Delays were 3, 6, 12, 24, 48, 72, and 96 hours; maximum delayed heroin amount was thirty $10 bags. Indifference points were used to calculate area under the curve (AUC). We also assessed drug-use impulsivity (subscales from the Impulsive Relapse Questionnaire [IRQ]) and estimated intelligence (Shipley IQ) as predictors of DD. Heroin discounting was greater (smaller AUC) during withdrawal than satiation. In regression analyses, lower intelligence and IRQ Capacity for Delay as well as higher IRQ Speed (to return to drug use) predicted greater heroin discounting in the satiation condition. Lower intelligence and higher IRQ Speed predicted greater discounting in the withdrawal condition. Sex, race, substance use variables, and other IRQ subscales were not significantly related to the withdrawal or satiation DD behavior. In summary, heroin discounting was temporally rapid, pharmacologically state dependent, and predicted by drug-use impulsivity and estimated intelligence. These findings highlight a novel and sensitive measure of acute DD that is easy to administer. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

  12. Roll paper pilot. [mathematical model for predicting pilot rating of aircraft in roll task

    Science.gov (United States)

    Naylor, F. R.; Dillow, J. D.; Hannen, R. A.

    1973-01-01

    A mathematical model for predicting the pilot rating of an aircraft in a roll task is described. The model includes: (1) the lateral-directional aircraft equations of motion; (2) a stochastic gust model; (3) a pilot model with two free parameters; and (4) a pilot rating expression that is a function of rms roll angle and the pilot lead time constant. The pilot gain and lead time constant are selected to minimize the pilot rating expression. The pilot parameters are then adjusted to provide a 20% stability margin and the adjusted pilot parameters are used to compute a roll paper pilot rating of the aircraft/gust configuration. The roll paper pilot rating was computed for 25 aircraft/gust configurations. A range of actual ratings from 2 to 9 were encountered and the roll paper pilot ratings agree quite well with the actual ratings. In addition there is good correlation between predicted and measured rms roll angle.

  13. Prediction of Oil Critical Rate in Vertical Wells using Meyer-Gardner ...

    African Journals Online (AJOL)

    PROF HORSFALL

    2018-04-14

    Apr 14, 2018 ... Department of Petroleum and Gas Engineering, Faculty of Engineering, Delta State University, Abraka, Delta State, ..... impermeable barrier, extending radially from the ... useful aid to field engineers for predicting critical rate.

  14. New England observed and predicted August stream/river temperature maximum daily rate of change points

    Data.gov (United States)

    U.S. Environmental Protection Agency — The shapefile contains points with associated observed and predicted August stream/river temperature maximum negative rate of change in New England based on a...

  15. Semantic Factors Predict the Rate of Lexical Replacement of Content Words

    OpenAIRE

    Vejdemo, Susanne; H?rberg, Thomas

    2016-01-01

    The rate of lexical replacement estimates the diachronic stability of word forms on the basis of how frequently a proto-language word is replaced or retained in its daughter languages. Lexical replacement rate has been shown to be highly related to word class and word frequency. In this paper, we argue that content words and function words behave differently with respect to lexical replacement rate, and we show that semantic factors predict the lexical replacement rate of content words. For t...

  16. Predictability of Exchange Rates in Sri Lanka: A Test of the Efficient Market Hypothesis

    OpenAIRE

    Guneratne B Wickremasinghe

    2007-01-01

    This study examined the validity of the weak and semi-strong forms of the efficient market hypothesis (EMH) for the foreign exchange market of Sri Lanka. Monthly exchange rates for four currencies during the floating exchange rate regime were used in the empirical tests. Using a battery of tests, empirical results indicate that the current values of the four exchange rates can be predicted from their past values. Further, the tests of semi-strong form efficiency indicate that exchange rate pa...

  17. A Prediction Model for Community Colleges Using Graduation Rate as the Performance Indicator

    Science.gov (United States)

    Moosai, Susan

    2010-01-01

    In this thesis a prediction model using graduation rate as the performance indicator is obtained for community colleges for three cohort years, 2003, 2004, and 2005 in the states of California, Florida, and Michigan. Multiple Regression analysis, using an aggregate of seven predictor variables, was employed in determining this prediction model.…

  18. Prediction of creamy mouthfeel based on texture attribute ratings of dairy desserts

    NARCIS (Netherlands)

    Weenen, H.; Jellema, R.H.; Wijk, de R.A.

    2006-01-01

    A quantitative predictive model for creamy mouthfeel in dairy desserts was developed, using PLS multivariate analysis of texture attributes. Based on 40 experimental custard desserts, a good correlation was obtained between measured and predicted creamy mouthfeel ratings. The model was validated by

  19. Error associated with model predictions of wildland fire rate of spread

    Science.gov (United States)

    Miguel G. Cruz; Martin E. Alexander

    2015-01-01

    How well can we expect to predict the spread rate of wildfires and prescribed fires? The degree of accuracy in model predictions of wildland fire behaviour characteristics are dependent on the model's applicability to a given situation, the validity of the model's relationships, and the reliability of the model input data (Alexander and Cruz 2013b#. We...

  20. Prediction of the dollar to the ruble rate. A system-theoretic approach

    Science.gov (United States)

    Borodachev, Sergey M.

    2017-07-01

    Proposed a simple state-space model of dollar rate formation based on changes in oil prices and some mechanisms of money transfer between monetary and stock markets. Comparison of predictions by means of input-output model and state-space model is made. It concludes that with proper use of statistical data (Kalman filter) the second approach provides more adequate predictions of the dollar rate.

  1. Testable Implications of Quasi-Hyperbolic and Exponential Time Discounting

    OpenAIRE

    Echenique, Federico; Imai, Taisuke; Saito, Kota

    2014-01-01

    We present the first revealed-preference characterizations of the models of exponential time discounting, quasi-hyperbolic time discounting, and other time-separable models of consumers’ intertemporal decisions. The characterizations provide non-parametric revealed-preference tests, which we take to data using the results of a recent experiment conducted by Andreoni and Sprenger (2012). For such data, we find that less than half the subjects are consistent with exponential discounting, and on...

  2. The effects of the framing of time on delay discounting.

    Science.gov (United States)

    DeHart, William Brady; Odum, Amy L

    2015-01-01

    We examined the effects of the framing of time on delay discounting. Delay discounting is the process by which delayed outcomes are devalued as a function of time. Time in a titrating delay discounting task is often framed in calendar units (e.g., as 1 week, 1 month, etc.). When time is framed as a specific date, delayed outcomes are discounted less compared to the calendar format. Other forms of framing time; however, have not been explored. All participants completed a titrating calendar unit delay-discounting task for money. Participants were also assigned to one of two delay discounting tasks: time as dates (e.g., June 1st, 2015) or time in units of days (e.g., 5000 days), using the same delay distribution as the calendar delay-discounting task. Time framed as dates resulted in less discounting compared to the calendar method, whereas time framed as days resulted in greater discounting compared to the calendar method. The hyperboloid model fit best compared to the hyperbola and exponential models. How time is framed may alter how participants attend to the delays as well as how the delayed outcome is valued. Altering how time is framed may serve to improve adherence to goals with delayed outcomes. © Society for the Experimental Analysis of Behavior.

  3. Prediction on corrosion rate of pipe in nuclear power system based on optimized grey theory

    International Nuclear Information System (INIS)

    Chen Yonghong; Zhang Dafa; Chen Dengke; Jiang Wei

    2007-01-01

    For the prediction of corrosion rate of pipe in nuclear power system, the pre- diction error from the grey theory is greater, so a new method, optimized grey theory was presented in the paper. A comparison among predicted results from present and other methods was carried out, and it is seem that optimized grey theory is correct and effective for the prediction of corrosion rate of pipe in nuclear power system, and it provides a fundamental basis for the maintenance of pipe in nuclear power system. (authors)

  4. How hyperbolic discounting preference affects Chinese consumers’ consumption choice between conventional and electric vehicles

    International Nuclear Information System (INIS)

    Wu, Tian; Shang, Zhe; Tian, Xin; Wang, Shouyang

    2016-01-01

    This paper presents a theoretical model and addresses several issues related to life cycle cost analysis to illustrate how time-inconsistent preferences affect consumer choice. The particular case study selects involved consumer choice between a vehicle with high initial acquisition cost but low ownership cost (e.g., an Electric Vehicle, EV) and one with a low initial acquisition cost but high ownership cost (e.g., a conventional Internal Combustion Engine Vehicle, ICEV). To test our theoretical analysis, we conduct an empirical study on how time discounting rates affect consumer choice between ICEVs and EVs with different initial cost ratios. From the survey results, we find that individuals with higher present bias showed irrational purchase behavior even when controlling for wealth level. Specifically, people making some “stronger bias to present” decisions chose higher total cost ICEVs with lower initial cost but higher ownership cost over lower total cost EVs with higher initial cost and lower ownership cost. However, people’s long-term discount is not correlated with irrational vehicle purchase behavior. Furthermore, we study the present bias and long-term discount rate in one scenario and found present bias to be correlated with irrational behavior. - Highlights: • Theoretical model and survey based on psychological experiment are used for study. • Time inconsistency preferences may affect consumers' rational purchasing choice. • Present bias is correlated with irrational behavior, but long-term discount is not.

  5. Harnessing atomistic simulations to predict the rate at which dislocations overcome obstacles

    Science.gov (United States)

    Saroukhani, S.; Nguyen, L. D.; Leung, K. W. K.; Singh, C. V.; Warner, D. H.

    2016-05-01

    Predicting the rate at which dislocations overcome obstacles is key to understanding the microscopic features that govern the plastic flow of modern alloys. In this spirit, the current manuscript examines the rate at which an edge dislocation overcomes an obstacle in aluminum. Predictions were made using different popular variants of Harmonic Transition State Theory (HTST) and compared to those of direct Molecular Dynamics (MD) simulations. The HTST predictions were found to be grossly inaccurate due to the large entropy barrier associated with the dislocation-obstacle interaction. Considering the importance of finite temperature effects, the utility of the Finite Temperature String (FTS) method was then explored. While this approach was found capable of identifying a prominent reaction tube, it was not capable of computing the free energy profile along the tube. Lastly, the utility of the Transition Interface Sampling (TIS) approach was explored, which does not need a free energy profile and is known to be less reliant on the choice of reaction coordinate. The TIS approach was found capable of accurately predicting the rate, relative to direct MD simulations. This finding was utilized to examine the temperature and load dependence of the dislocation-obstacle interaction in a simple periodic cell configuration. An attractive rate prediction approach combining TST and simple continuum models is identified, and the strain rate sensitivity of individual dislocation obstacle interactions is predicted.

  6. Developing models for the prediction of hospital healthcare waste generation rate.

    Science.gov (United States)

    Tesfahun, Esubalew; Kumie, Abera; Beyene, Abebe

    2016-01-01

    An increase in the number of health institutions, along with frequent use of disposable medical products, has contributed to the increase of healthcare waste generation rate. For proper handling of healthcare waste, it is crucial to predict the amount of waste generation beforehand. Predictive models can help to optimise healthcare waste management systems, set guidelines and evaluate the prevailing strategies for healthcare waste handling and disposal. However, there is no mathematical model developed for Ethiopian hospitals to predict healthcare waste generation rate. Therefore, the objective of this research was to develop models for the prediction of a healthcare waste generation rate. A longitudinal study design was used to generate long-term data on solid healthcare waste composition, generation rate and develop predictive models. The results revealed that the healthcare waste generation rate has a strong linear correlation with the number of inpatients (R(2) = 0.965), and a weak one with the number of outpatients (R(2) = 0.424). Statistical analysis was carried out to develop models for the prediction of the quantity of waste generated at each hospital (public, teaching and private). In these models, the number of inpatients and outpatients were revealed to be significant factors on the quantity of waste generated. The influence of the number of inpatients and outpatients treated varies at different hospitals. Therefore, different models were developed based on the types of hospitals. © The Author(s) 2015.

  7. Sensitivity Analysis of Corrosion Rate Prediction Models Utilized for Reinforced Concrete Affected by Chloride

    Science.gov (United States)

    Siamphukdee, Kanjana; Collins, Frank; Zou, Roger

    2013-06-01

    Chloride-induced reinforcement corrosion is one of the major causes of premature deterioration in reinforced concrete (RC) structures. Given the high maintenance and replacement costs, accurate modeling of RC deterioration is indispensable for ensuring the optimal allocation of limited economic resources. Since corrosion rate is one of the major factors influencing the rate of deterioration, many predictive models exist. However, because the existing models use very different sets of input parameters, the choice of model for RC deterioration is made difficult. Although the factors affecting corrosion rate are frequently reported in the literature, there is no published quantitative study on the sensitivity of predicted corrosion rate to the various input parameters. This paper presents the results of the sensitivity analysis of the input parameters for nine selected corrosion rate prediction models. Three different methods of analysis are used to determine and compare the sensitivity of corrosion rate to various input parameters: (i) univariate regression analysis, (ii) multivariate regression analysis, and (iii) sensitivity index. The results from the analysis have quantitatively verified that the corrosion rate of steel reinforcement bars in RC structures is highly sensitive to corrosion duration time, concrete resistivity, and concrete chloride content. These important findings establish that future empirical models for predicting corrosion rate of RC should carefully consider and incorporate these input parameters.

  8. Predicting Graduation Rates at 4-Year Broad Access Institutions Using a Bayesian Modeling Approach

    Science.gov (United States)

    Crisp, Gloria; Doran, Erin; Salis Reyes, Nicole A.

    2018-01-01

    This study models graduation rates at 4-year broad access institutions (BAIs). We examine the student body, structural-demographic, and financial characteristics that best predict 6-year graduation rates across two time periods (2008-2009 and 2014-2015). A Bayesian model averaging approach is utilized to account for uncertainty in variable…

  9. Predicting higher education graduation rates from institutional characteristics and resource allocation

    OpenAIRE

    Florence A. Hamrick; John H. Schuh; Mack C. Shelley

    2004-01-01

    This study incorporated institutional characteristics (e.g., Carnegie type, selectivity) and resource allocations (e.g., instructional expenditures, student affairs expenditures) into a statistical model to predict undergraduate graduation rates. Instructional expenditures, library expenditures, and a number of institutional classification variables were significant predictors of graduation rates. Based on these results, recommendations as well as warranted cautions are included about allocat...

  10. Model for the evaluation and prediction of production rate of sinter ...

    African Journals Online (AJOL)

    A model has been derived for evaluation and prediction of production rate of sinter machine operating on vertical mode. The quadratic model expressed as: P = 0.4395 V – 0.0526 V2 + 0.54, showed that the production rate of the sinter machine was dependent on the vertical sintering height. The maximum deviation of the ...

  11. Age, gender and deterrability: Are younger male drivers more likely to discount the future?

    Science.gov (United States)

    Freeman, James; Kaye, Sherrie-Anne; Truelove, Verity; Davey, Jeremy

    2017-07-01

    Utilizing the Classical Deterrence theory and Stafford and Warr's (1993) reconceptualized model of deterrence, the current study examined whether age, gender, and discounting the future tendencies influence perceptions of being apprehended for speeding offences. Licensed motorists (N=700; 57% female) in Queensland (Australia) were recruited to complete a self-report questionnaire that measured perceptual deterrence, speeding related behaviors and discounting the future tendencies. Data were analyzed utilizing descriptive, bivariate and multivariate regressions. Significant (albeit weak) positive correlations were found between age and perceptions of apprehension certainty. Males were significantly more likely to report higher incidences of speeding (including while avoiding detection) compared to females. In contrast, females were more likely to perceive high levels of apprehension certainty and consider impending penalties to be more severe. At a multivariate level, discounting the future tendencies (in addition to being male, reporting lower levels of perceptual severity and swiftness, and more instances of punishment avoidance) were predictive of lower perceptual certainty levels. This study is one of the first to reveal that being male and having a tendency to discount the consequences of the future may directly influence drivers' perceptual deterrence levels. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Predicting higher education graduation rates from institutional characteristics and resource allocation

    Directory of Open Access Journals (Sweden)

    Florence A. Hamrick

    2004-05-01

    Full Text Available This study incorporated institutional characteristics (e.g., Carnegie type, selectivity and resource allocations (e.g., instructional expenditures, student affairs expenditures into a statistical model to predict undergraduate graduation rates. Instructional expenditures, library expenditures, and a number of institutional classification variables were significant predictors of graduation rates. Based on these results, recommendations as well as warranted cautions are included about allocating academic financial resources to optimize graduation rates

  13. Assessment of heart rate, acidosis, consciousness, oxygenation, and respiratory rate to predict noninvasive ventilation failure in hypoxemic patients.

    Science.gov (United States)

    Duan, Jun; Han, Xiaoli; Bai, Linfu; Zhou, Lintong; Huang, Shicong

    2017-02-01

    To develop and validate a scale using variables easily obtained at the bedside for prediction of failure of noninvasive ventilation (NIV) in hypoxemic patients. The test cohort comprised 449 patients with hypoxemia who were receiving NIV. This cohort was used to develop a scale that considers heart rate, acidosis, consciousness, oxygenation, and respiratory rate (referred to as the HACOR scale) to predict NIV failure, defined as need for intubation after NIV intervention. The highest possible score was 25 points. To validate the scale, a separate group of 358 hypoxemic patients were enrolled in the validation cohort. The failure rate of NIV was 47.8 and 39.4% in the test and validation cohorts, respectively. In the test cohort, patients with NIV failure had higher HACOR scores at initiation and after 1, 12, 24, and 48 h of NIV than those with successful NIV. At 1 h of NIV the area under the receiver operating characteristic curve was 0.88, showing good predictive power for NIV failure. Using 5 points as the cutoff value, the sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy for NIV failure were 72.6, 90.2, 87.2, 78.1, and 81.8%, respectively. These results were confirmed in the validation cohort. Moreover, the diagnostic accuracy for NIV failure exceeded 80% in subgroups classified by diagnosis, age, or disease severity and also at 1, 12, 24, and 48 h of NIV. Among patients with NIV failure with a HACOR score of >5 at 1 h of NIV, hospital mortality was lower in those who received intubation at ≤12 h of NIV than in those intubated later [58/88 (66%) vs. 138/175 (79%); p = 0.03). The HACOR scale variables are easily obtained at the bedside. The scale appears to be an effective way of predicting NIV failure in hypoxemic patients. Early intubation in high-risk patients may reduce hospital mortality.

  14. Predicting hepatitis B monthly incidence rates using weighted Markov chains and time series methods.

    Science.gov (United States)

    Shahdoust, Maryam; Sadeghifar, Majid; Poorolajal, Jalal; Javanrooh, Niloofar; Amini, Payam

    2015-01-01

    Hepatitis B (HB) is a major global mortality. Accurately predicting the trend of the disease can provide an appropriate view to make health policy disease prevention. This paper aimed to apply three different to predict monthly incidence rates of HB. This historical cohort study was conducted on the HB incidence data of Hamadan Province, the west of Iran, from 2004 to 2012. Weighted Markov Chain (WMC) method based on Markov chain theory and two time series models including Holt Exponential Smoothing (HES) and SARIMA were applied on the data. The results of different applied methods were compared to correct percentages of predicted incidence rates. The monthly incidence rates were clustered into two clusters as state of Markov chain. The correct predicted percentage of the first and second clusters for WMC, HES and SARIMA methods was (100, 0), (84, 67) and (79, 47) respectively. The overall incidence rate of HBV is estimated to decrease over time. The comparison of results of the three models indicated that in respect to existing seasonality trend and non-stationarity, the HES had the most accurate prediction of the incidence rates.

  15. Covariance of random stock prices in the Stochastic Dividend Discount Model

    OpenAIRE

    Agosto, Arianna; Mainini, Alessandra; Moretto, Enrico

    2016-01-01

    Dividend discount models have been developed in a deterministic setting. Some authors (Hurley and Johnson, 1994 and 1998; Yao, 1997) have introduced randomness in terms of stochastic growth rates, delivering closed-form expressions for the expected value of stock prices. This paper extends such previous results by determining a formula for the covariance between random stock prices when the dividends' rates of growth are correlated. The formula is eventually applied to real market data.

  16. The economic feasibility of price discounts to improve diet in Australian Aboriginal remote communities.

    Science.gov (United States)

    Magnus, Anne; Moodie, Marj L; Ferguson, Megan; Cobiac, Linda J; Liberato, Selma C; Brimblecombe, Julie

    2016-04-01

    To estimate the cost-effectiveness of fiscal measures applied in remote community food stores for Aboriginal Australians. Six price discount strategies on fruit, vegetables, diet drinks and water were modelled. Baseline diet was measured as 12 months' actual food sales data in three remote Aboriginal communities. Discount-induced changes in food purchases were based on published price elasticity data while the weight of the daily diet was assumed constant. Dietary change was converted to change in sodium and energy intake, and body mass index (BMI) over a 12-month period. Improved lifetime health outcomes, modelled for the remote population of Aboriginal and Torres Strait Islanders, were converted to disability adjusted life years (DALYs) saved using a proportional multistate lifetable model populated with diet-related disease risks and Aboriginal and Torres Strait Islander rates of disease. While dietary change was small, five of the six price discount strategies were estimated as cost-effective, below a $50,000/DALY threshold. Stakeholders are committed to finding ways to reduce important inequalities in health status between Aboriginal and Torres Strait Islanders and non-Indigenous Australians. Price discounts offer potential to improve Aboriginal and Torres Strait Islander health. Verification of these results by trial-based research coupled with consideration of factors important to all stakeholders is needed. © 2015 The Authors.

  17. Supply Chain Coordination under Trade Credit and Quantity Discount with Sales Effort Effects

    Directory of Open Access Journals (Sweden)

    Zhihong Wang

    2018-01-01

    Full Text Available The purpose of this paper is to investigate the role of trade credit and quantity discount in supply chain coordination when the sales effort effect on market demand is considered. In this paper, we consider a two-echelon supply chain consisting of a single retailer ordering a single product from a single manufacturer. Market demand is stochastic and is influenced by retailer sales effort. We formulate an analytical model based on a single trade credit and find that the single trade credit cannot achieve the perfect coordination of the supply chain. Then, we develop a hybrid quantitative analytical model for supply chain coordination by coherently integrating incentives of trade credit and quantity discount with sales effort effects. The results demonstrate that, providing that the discount rate satisfies certain conditions, the proposed hybrid model combining trade credit and quantity discount will be able to effectively coordinate the supply chain by motivating retailers to exert their sales effort and increase product order quantity. Furthermore, the hybrid quantitative analytical model can provide great flexibility in coordinating the supply chain to achieve an optimal situation through the adjustment of relevant parameters to resolve conflict of interests from different supply chain members. Numerical examples are provided to demonstrate the effectiveness of the hybrid model.

  18. Shallow discounting of delayed cocaine by male rhesus monkeys when immediate food is the choice alternative.

    Science.gov (United States)

    Huskinson, Sally L; Myerson, Joel; Green, Leonard; Rowlett, James K; Woolverton, William L; Freeman, Kevin B

    2016-12-01

    Huskinson et al. (2015) recently examined delay discounting in monkeys choosing between an immediate drug (cocaine) reinforcer and a delayed nondrug (food) reinforcer. The present experiment examined the reverse situation: choice between immediate nondrug (food) and delayed drug (cocaine) reinforcers. Whereas the former choice situation exemplifies drug abuse from a delay-discounting perspective, our interest in the latter choice situation is derived from the observation that drug abusers, who characteristically are associated with impulsive choice, typically must devote considerable time to procuring drugs, often at the expense of immediate nondrug alternatives. Accordingly, we analyzed 3 male rhesus monkeys' choices between immediate food and delayed cocaine (0.1 and 0.2 mg/kg/injection) using a hyperbolic model that allowed us to compare discounting rates between qualitatively different reinforcers. Choice of immediate food increased with food amount, and choice functions generally shifted leftward as delay to cocaine increased, indicating a decrease in the subjective value of cocaine. Compared with our previous delay-discounting experiment with immediate cocaine versus delayed food, both doses of delayed cocaine were discounted at a shallow rate. The present results demonstrate that rhesus monkeys will tolerate relatively long delays in an immediate-food versus delayed-drug situation, suggesting that in intertemporal choices between cocaine and food, the subjective value of cocaine is less affected by the delay until reinforcement than is the subjective value of delayed food. More generally, the present findings suggest that although drug abusers may choose impulsively when immediate drug reinforcement is available, they exercise self-control in the acquisition of a highly preferred, delayed drug reinforcer. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  19. Parabolic discounting of monetary rewards by physical effort

    NARCIS (Netherlands)

    Hartmann, M.N.; Hager, O.M.; Tobler, P.N.; Kaiser, S.

    2013-01-01

    When humans and other animals make decisions in their natural environments prospective rewards have to be weighed against costs. It is well established that increasing costs lead to devaluation or discounting of reward. While our knowledge about discount functions for time and probability costs is

  20. Zero discounting can compensate future generations for climate damage

    NARCIS (Netherlands)

    Davidson, M.D.

    2014-01-01

    In cost-benefit analysis of climate policy there are two main approaches to discounting, each with implications conflicting with our moral intuitions. Thus, discounted utilitarianism implies that we hardly need to protect future generations against climate change, while classical utilitarianism

  1. Internet Addiction and Delay Discounting in College Students

    Science.gov (United States)

    Saville, Bryan K.; Gisbert, Amanda; Kopp, Jason; Telesco, Carolyn

    2010-01-01

    To examine the relation between Internet addiction and delay discounting, we gave 276 college students a survey designed to measure Internet addiction and a paper-based delay-discounting task. In our larger sample, we identified 14 students who met the criteria for Internet addiction; we also identified 14 matched controls who were similar to the…

  2. Brain Structure Linking Delay Discounting and Academic Performance.

    Science.gov (United States)

    Wang, Song; Kong, Feng; Zhou, Ming; Chen, Taolin; Yang, Xun; Chen, Guangxiang; Gong, Qiyong

    2017-08-01

    As a component of self-discipline, delay discounting refers to the ability to wait longer for preferred rewards and plays a pivotal role in shaping students' academic performance. However, the neural basis of the association between delay discounting and academic performance remains largely unknown. Here, we examined the neuroanatomical substrates underlying delay discounting and academic performance in 214 adolescents via voxel-based morphometry (VBM) by performing structural magnetic resonance imaging (S-MRI). Behaviorally, we confirmed the significant correlation between delay discounting and academic performance. Neurally, whole-brain regression analyses indicated that regional gray matter volume (rGMV) of the left dorsolateral prefrontal cortex (DLPFC) was associated with both delay discounting and academic performance. Furthermore, delay discounting partly accounted for the association between academic performance and brain structure. Differences in the rGMV of the left DLPFC related to academic performance explained over one-third of the impact of delay discounting on academic performance. Overall, these results provide the first evidence for the common neural basis linking delay discounting and academic performance. Hum Brain Mapp 38:3917-3926, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  3. The Students Decision Making in Solving Discount Problem

    Science.gov (United States)

    Abdillah; Nusantara, Toto; Subanji; Susanto, Hery; Abadyo

    2016-01-01

    This research is reviewing students' process of decision making intuitively, analytically, and interactively. The research done by using discount problem which specially created to explore student's intuition, analytically, and interactively. In solving discount problems, researcher exploring student's decision in determining their attitude which…

  4. Kalman Filter or VAR Models to Predict Unemployment Rate in Romania?

    Directory of Open Access Journals (Sweden)

    Simionescu Mihaela

    2015-06-01

    Full Text Available This paper brings to light an economic problem that frequently appears in practice: For the same variable, more alternative forecasts are proposed, yet the decision-making process requires the use of a single prediction. Therefore, a forecast assessment is necessary to select the best prediction. The aim of this research is to propose some strategies for improving the unemployment rate forecast in Romania by conducting a comparative accuracy analysis of unemployment rate forecasts based on two quantitative methods: Kalman filter and vector-auto-regressive (VAR models. The first method considers the evolution of unemployment components, while the VAR model takes into account the interdependencies between the unemployment rate and the inflation rate. According to the Granger causality test, the inflation rate in the first difference is a cause of the unemployment rate in the first difference, these data sets being stationary. For the unemployment rate forecasts for 2010-2012 in Romania, the VAR models (in all variants of VAR simulations determined more accurate predictions than Kalman filter based on two state space models for all accuracy measures. According to mean absolute scaled error, the dynamic-stochastic simulations used in predicting unemployment based on the VAR model are the most accurate. Another strategy for improving the initial forecasts based on the Kalman filter used the adjusted unemployment data transformed by the application of the Hodrick-Prescott filter. However, the use of VAR models rather than different variants of the Kalman filter methods remains the best strategy in improving the quality of the unemployment rate forecast in Romania. The explanation of these results is related to the fact that the interaction of unemployment with inflation provides useful information for predictions of the evolution of unemployment related to its components (i.e., natural unemployment and cyclical component.

  5. [Prediction of schistosomiasis infection rates of population based on ARIMA-NARNN model].

    Science.gov (United States)

    Ke-Wei, Wang; Yu, Wu; Jin-Ping, Li; Yu-Yu, Jiang

    2016-07-12

    To explore the effect of the autoregressive integrated moving average model-nonlinear auto-regressive neural network (ARIMA-NARNN) model on predicting schistosomiasis infection rates of population. The ARIMA model, NARNN model and ARIMA-NARNN model were established based on monthly schistosomiasis infection rates from January 2005 to February 2015 in Jiangsu Province, China. The fitting and prediction performances of the three models were compared. Compared to the ARIMA model and NARNN model, the mean square error (MSE), mean absolute error (MAE) and mean absolute percentage error (MAPE) of the ARIMA-NARNN model were the least with the values of 0.011 1, 0.090 0 and 0.282 4, respectively. The ARIMA-NARNN model could effectively fit and predict schistosomiasis infection rates of population, which might have a great application value for the prevention and control of schistosomiasis.

  6. Delay and probability discounting among payday and title loan recipients.

    Science.gov (United States)

    Mahoney, Colin T; Lawyer, Steven R

    2016-04-01

    Payday and title loans are short-term loans associated with significant economic impact. Behavioral theories of impulsive choice may provide insight into behavioral processes that underlie the propensity to take out payday and title loans. Adults between the ages of 18 and 30 recruited from the community completed delay and probability discounting tasks for hypothetical money as well as measures of substance use. Patterns of discounting were characterized using a hyperbolic decay model and area under the curve. Participants who took out a payday and/or title loan in the past (n=41) exhibited more impulsive choice patterns on the delay discounting task than did those who did not (n=255). Substance use mediated this relationship between payday and title loan retention and delay discounting. These findings suggest potentially important relationships between payday/title loan borrowing, substance use, and delay discounting. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Advertisement Click-Through Rate Prediction Based on the Weighted-ELM and Adaboost Algorithm

    Directory of Open Access Journals (Sweden)

    Sen Zhang

    2017-01-01

    Full Text Available Accurate click-through rate (CTR prediction can not only improve the advertisement company’s reputation and revenue, but also help the advertisers to optimize the advertising performance. There are two main unsolved problems of the CTR prediction: low prediction accuracy due to the imbalanced distribution of the advertising data and the lack of the real-time advertisement bidding implementation. In this paper, we will develop a novel online CTR prediction approach by incorporating the real-time bidding (RTB advertising by the following strategies: user profile system is constructed from the historical data of the RTB advertising to describe the user features, the historical CTR features, the ID features, and the other numerical features. A novel CTR prediction approach is presented to address the imbalanced learning sample distribution by integrating the Weighted-ELM (WELM and the Adaboost algorithm. Compared to the commonly used algorithms, the proposed approach can improve the CTR significantly.

  8. Sensitivity, specificity, predictive value and accuracy of ultrasonography in pregnancy rate prediction in Sahelian goats after progesterone impregnated sponge synchronization

    Directory of Open Access Journals (Sweden)

    Justin Kouamo

    2014-09-01

    Full Text Available Aim: This study was aimed to evaluate the sensitivity, specificity, predictive value and accuracy of ultrasonography in pregnancy rate (PR prediction in Sahelian goats after progesterone impregnated sponge synchronization within the framework of caprine artificial insemination (AI program in Fatick (Senegal. Materials and Methods: Of 193 candidate goats in AI program, 167 were selected (day 50 in six villages. Estrus was synchronized by progesterone impregnated sponges installed for 11 days. Two days before the time of sponge removal (day 4, each goat was treated with 500 IU of equine chorionic gonadotropin and 50 μg of dcloprostenol. All goats were inseminated (day 0 with alpine goat semen from France at 45±3 h after sponge removal (day 2. Real-time B-mode ultrasonography was performed at day 50, day 13, day 0, day 40 and day 60 post-AI. Results: Selection rate, estrus response rate, AI rate, PR at days 40 and days 60 were 86.53%; 71.85%; 83.34%; 51% and 68% (p<0.05 respectively. Value of sensitivity, specificity, positive and negative predictive value, accuracy, total conformity, conformity of correct positive, conformity of correct negative and discordance of pregnancy diagnosis by trans-abdominal ultrasonography (TU were 98.03%; 63.26%; 73.52%; 3.12%; 81%; 81%; 50%; 31% and 19%, respectively. Conclusion: These results indicate that the TU can be performed in goats under traditional condition and emphasized the importance of re-examination of goats with negative or doubtful TU diagnoses performed at day 40 post-AI.

  9. WORK COMPETENCES AT WESTERN BANK DISCOUNT

    Directory of Open Access Journals (Sweden)

    Haidee Coste

    2017-03-01

    Full Text Available The research aimed to identify the generic work competences in the staff of the Vice Presidency of Compensation and Development of the Western Bank Discount. Authors were consulted such as Alles (2008, Tobon (2006 and Hay Group (2004, among others. The research is descriptive, non-experimental, transactional and field design. The population consisted of twelve (12 subjects belonging to the vice presidency. It was applied a questionnaire of thirty (30 items, validated by the trial of three (3 experts, with 0.92 reliability by Cronbach alpha coefficient.  It is concluded the employees of the vice presidency have a high level of the generic work competences customer focus, teamwork, effective communication, innovation, emotional intelligence and making decisions. It is strength for the institution, because staff with those competences contributes doing the best for the development of the institution.

  10. NEUTRON GENERATOR FACILITY AT SFU: GEANT4 DOSE RATE PREDICTION AND VERIFICATION.

    Science.gov (United States)

    Williams, J; Chester, A; Domingo, T; Rizwan, U; Starosta, K; Voss, P

    2016-11-01

    Detailed dose rate maps for a neutron generator facility at Simon Fraser University were produced via the GEANT4 Monte Carlo framework. Predicted neutron dose rates throughout the facility were compared with radiation survey measurements made during the facility commissioning process. When accounting for thermal neutrons, the prediction and measurement agree within a factor of 2 or better in most survey locations, and within 10 % inside the vault housing the neutron generator. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. A new constitutive model for prediction of impact rates response of polypropylene

    Directory of Open Access Journals (Sweden)

    Buckley C.P.

    2012-08-01

    Full Text Available This paper proposes a new constitutive model for predicting the impact rates response of polypropylene. Impact rates, as used here, refer to strain rates greater than 1000 1/s. The model is a physically based, three-dimensional constitutive model which incorporates the contributions of the amorphous, crystalline, pseudo-amorphous and entanglement networks to the constitutive response of polypropylene. The model mathematics is based on the well-known Glass-Rubber model originally developed for glassy polymers but the arguments have herein been extended to semi-crystalline polymers. In order to predict the impact rates behaviour of polypropylene, the model exploits the well-known framework of multiple processes yielding of polymers. This work argues that two dominant viscoelastic relaxation processes – the alpha- and beta-processes – can be associated with the yield responses of polypropylene observed at low-rate-dominant and impact-rates dominant loading regimes. Compression test data on polypropylene have been used to validate the model. The study has found that the model predicts quite well the experimentally observed nonlinear rate-dependent impact response of polypropylene.

  12. "What time is my next meal?" delay-discounting individuals choose smaller portions under conditions of uncertainty.

    Science.gov (United States)

    Zimmerman, Annie R; Ferriday, Danielle; Davies, Sarah R; Martin, Ashley A; Rogers, Peter J; Mason, Alice; Brunstrom, Jeffrey M

    2017-09-01

    'Dietary' delay discounting is typically framed as a trade-off between immediate rewards and long-term health concerns. Our contention is that prospective thinking also occurs over shorter periods, and is engaged to select portion sizes based on the interval between meals (inter-meal interval; IMI). We sought to assess the extent to which the length of an IMI influences portion-size selection. We predicted that delay discounters would show 'IMI insensitivity' (relative lack of concern about hunger or fullness between meals). In particular, we were interested in participants' sensitivity to an uncertain IMI. We hypothesized that when meal times were uncertain, delay discounters would be less responsive and select smaller portion sizes. Participants (N = 90) selected portion sizes for lunch. In different trials, they were told to expect dinner at 5pm, 9pm, and either 5pm or 9pm (uncertain IMI). Individual differences in future-orientation were measured using a monetary delay-discounting task. Participants chose larger portions when the IMI was longer (p relationship between BMI and smaller portion selection in uncertainty (p < 0.05). This is the first study to report an association between delay discounting and IMI insensitivity. We reason that delay discounters selected smaller portions because they were less sensitive to the uncertain IMI, and overlooked concerns about potential future hunger. These findings are important because they illustrate that differences in discounting are expressed in short-term portion-size decisions and suggest that IMI insensitivity increases when meal timings are uncertain. Further research is needed to confirm whether these findings generalise to other populations. Copyright © 2017. Published by Elsevier Ltd.

  13. Valuing companies by cash flow discounting: Ten methods and nine theories

    OpenAIRE

    Fernández , Pablo

    2002-01-01

    This paper is a summarized compendium of all the methods and theories on company valuation using cash flow discounting. The paper shows the ten most commonly used methods for valuing companies by cash flow discounting: 1) free cash flow discounted at the WACC; 2) equity cash flows discounted at the required return to equity; 3) capital cash flows discounted at the WACC before tax; 4) APV (Adjusted Present Value); 5) the business's risk-adjusted free cash flows discounted at the required retur...

  14. Equivalence of the different discounted cash flow valuation methods. Different alternatives for determining the discounted value of tax shields and their implications for the valuation

    OpenAIRE

    Fernández, Pablo

    1999-01-01

    This paper addresses the valuation of firms by cash flow discounting. The first part shows that the four most commonly used discounted cash flow valuation methods (free cash flow discounted at the WACC; cash flow available for equity holders discounted at the required return on the equity flows; capital cash flow discounted at the WACC before taxes; and Adjusted Present Value) always give the same value. This result is logical because all the methods analyse the same reality under the same hy...

  15. Discounting human lives: Uranium and global equity

    International Nuclear Information System (INIS)

    Goldman, B.A.

    1993-01-01

    Long-term, global environmental health risks complicate efforts to evaluate the efficiency and equity of economic activities from a public welfare perspective. This study sets out a practical framework based on the theory of neoclassical welfare economics for evaluating whether an economic activity yields such inefficient or inequitable net effects to justify government intervention from a variety of decision-making perspectives. It applies this empirical approach to the case of public policies that encouraged uranium production (the mining, milling, and refining of uranium ore) near Elliot Lake and Blind River in Northern Ontario. The analysis tests the two-fold hypothesis that if future negative externalities of production are considered along with past net effects, the these policies result in (1) an inefficient allocation of economic resources according to the potential Pareto criterion, and (2) an inequitable distribution of impacts according to Rawls' maximin criterion. The analytical framework to test these hypotheses has three parts: Risk-cost-benefit analysis, distributions analysis, and efficiency and equity analysis. Quantitative impacts are derived from empirical estimates of cost and benefit streams during 1956 to 1990, and modelled future cancer death costs. Net effects are aggregated to nine observations across three dimensions: Geographic, intergenerational, and social. Qualitative observations are provided about the boom-and-bust uranium economy, environmental burdens, and other unquantifiable impacts. The results illustrate how underlying normative assumptions overwhelm other aspects of efficiency and equity analyses of long-term, global environmental changes. These assumptions appear in discounting equations that ultimately derive from a priori allocations of rights to natural assets and corollary duties to protect such rights. More than two-thirds of the discounting scenarios yield inefficient outcomes and over ninety percent are inequitable

  16. Online physician ratings fail to predict actual performance on measures of quality, value, and peer review.

    Science.gov (United States)

    Daskivich, Timothy J; Houman, Justin; Fuller, Garth; Black, Jeanne T; Kim, Hyung L; Spiegel, Brennan

    2018-04-01

    Patients use online consumer ratings to identify high-performing physicians, but it is unclear if ratings are valid measures of clinical performance. We sought to determine whether online ratings of specialist physicians from 5 platforms predict quality of care, value of care, and peer-assessed physician performance. We conducted an observational study of 78 physicians representing 8 medical and surgical specialties. We assessed the association of consumer ratings with specialty-specific performance scores (metrics including adherence to Choosing Wisely measures, 30-day readmissions, length of stay, and adjusted cost of care), primary care physician peer-review scores, and administrator peer-review scores. Across ratings platforms, multivariable models showed no significant association between mean consumer ratings and specialty-specific performance scores (β-coefficient range, -0.04, 0.04), primary care physician scores (β-coefficient range, -0.01, 0.3), and administrator scores (β-coefficient range, -0.2, 0.1). There was no association between ratings and score subdomains addressing quality or value-based care. Among physicians in the lowest quartile of specialty-specific performance scores, only 5%-32% had consumer ratings in the lowest quartile across platforms. Ratings were consistent across platforms; a physician's score on one platform significantly predicted his/her score on another in 5 of 10 comparisons. Online ratings of specialist physicians do not predict objective measures of quality of care or peer assessment of clinical performance. Scores are consistent across platforms, suggesting that they jointly measure a latent construct that is unrelated to performance. Online consumer ratings should not be used in isolation to select physicians, given their poor association with clinical performance.

  17. Study (Prediction of Main Pipes Break Rates in Water Distribution Systems Using Intelligent and Regression Methods

    Directory of Open Access Journals (Sweden)

    Massoud Tabesh

    2011-07-01

    Full Text Available Optimum operation of water distribution networks is one of the priorities of sustainable development of water resources, considering the issues of increasing efficiency and decreasing the water losses. One of the key subjects in optimum operational management of water distribution systems is preparing rehabilitation and replacement schemes, prediction of pipes break rate and evaluation of their reliability. Several approaches have been presented in recent years regarding prediction of pipe failure rates which each one requires especial data sets. Deterministic models based on age and deterministic multi variables and stochastic group modeling are examples of the solutions which relate pipe break rates to parameters like age, material and diameters. In this paper besides the mentioned parameters, more factors such as pipe depth and hydraulic pressures are considered as well. Then using multi variable regression method, intelligent approaches (Artificial neural network and neuro fuzzy models and Evolutionary polynomial Regression method (EPR pipe burst rate are predicted. To evaluate the results of different approaches, a case study is carried out in a part ofMashhadwater distribution network. The results show the capability and advantages of ANN and EPR methods to predict pipe break rates, in comparison with neuro fuzzy and multi-variable regression methods.

  18. Among nonagenarians, congruence between self-rated and proxy-rated health was low but both predicted mortality.

    Science.gov (United States)

    Vuorisalmi, Merja; Sarkeala, Tytti; Hervonen, Antti; Jylhä, Marja

    2012-05-01

    The congruence between self-rated global health (SRH) and proxy-rated global health (PRH), the factors associated with congruence between SRH and PRH, and their associations with mortality are examined using data from the Vitality 90+ study. The data consist of 213 pairs of subjects--aged 90 years and older--and proxies. The relationship between SRH and PRH was analyzed by chi-square test and Cohen's kappa. Logistic regression analysis was used to find out the factors that are associated with the congruence between health ratings. The association between SRH and PRH with mortality was studied using Cox proportional hazard models. The subjects rated their health more negatively than the proxies. Kappa value indicated only slight congruence between SRH and PRH, and they also predicted mortality differently. Good self-reported functional ability was associated with congruence between SRH and PRH. The results imply that the evaluation processes of SRH and PRH differ, and the measures are not directly interchangeable. Both measures are useful health indicators in very old age but SRH cannot be replaced by PRH in analyses. Copyright © 2012 Elsevier Inc. All rights reserved.

  19. Emotional exhaustion and workload predict clinician-rated and objective patient safety

    Science.gov (United States)

    Welp, Annalena; Meier, Laurenz L.; Manser, Tanja

    2015-01-01

    Aims: To investigate the role of clinician burnout, demographic, and organizational characteristics in predicting subjective and objective indicators of patient safety. Background: Maintaining clinician health and ensuring safe patient care are important goals for hospitals. While these goals are not independent from each other, the interplay between clinician psychological health, demographic and organizational variables, and objective patient safety indicators is poorly understood. The present study addresses this gap. Method: Participants were 1425 physicians and nurses working in intensive care. Regression analysis (multilevel) was used to investigate the effect of burnout as an indicator of psychological health, demographic (e.g., professional role and experience) and organizational (e.g., workload, predictability) characteristics on standardized mortality ratios, length of stay and clinician-rated patient safety. Results: Clinician-rated patient safety was associated with burnout, trainee status, and professional role. Mortality was predicted by emotional exhaustion. Length of stay was predicted by workload. Contrary to our expectations, burnout did not predict length of stay, and workload and predictability did not predict standardized mortality ratios. Conclusion: At least in the short-term, clinicians seem to be able to maintain safety despite high workload and low predictability. Nevertheless, burnout poses a safety risk. Subjectively, burnt-out clinicians rated safety lower, and objectively, units with high emotional exhaustion had higher standardized mortality ratios. In summary, our results indicate that clinician psychological health and patient safety could be managed simultaneously. Further research needs to establish causal relationships between these variables and support to the development of managerial guidelines to ensure clinicians’ psychological health and patients’ safety. PMID:25657627

  20. Emotional Exhaustion and Workload Predict Clinician-Rated and Objective Patient Safety

    Directory of Open Access Journals (Sweden)

    Annalena eWelp

    2015-01-01

    Full Text Available Aims: To investigate the role of clinician burnout, demographic and organizational characteristics in predicting subjective and objective indicators of patient safety. Background: Maintaining clinician health and ensuring safe patient care are important goals for hospitals. While these goals are not independent from each other, the interplay between clinician psychological health, demographic and organizational variables and objective patient safety indicators is poorly understood. The present study addresses this gap. Method: Participants were 1425 physicians and nurses working in intensive care. (Multilevel regression analysis was used to investigate the effect of burnout as an indicator of psychological health, demographic (e.g., professional role and experience and organizational (e.g., workload, predictability characteristics on standardized mortality ratios, length of stay and clinician-rated patient safety. Results: Clinician-rated patient safety were associated with burnout, trainee status, and professional role. Mortality was predicted by emotional exhaustion. Length of stay was predicted by workload. Contrary to our expectations, burnout did not predict length of stay, and workload and predictability did not predict standardized mortality ratios.Conclusion: At least in the short-term, clinicians seem to be able to maintain safety despite high workload and low predictability. Nevertheless, burnout poses a safety risk. Subjectively, burnt-out clinicians rated safety lower, and objectively, units with high emotional exhaustion had higher standardized mortality ratios. In summary, our results indicate that clinician psychological health and patient safety could be managed simultaneously. Further research needs to establish causal relationships between these variables or and support the development of managerial guidelines to ensure clinicians’ psychological health and patients’ safety.

  1. Modeling and Model Predictive Power and Rate Control of Wireless Communication Networks

    Directory of Open Access Journals (Sweden)

    Cunwu Han

    2014-01-01

    Full Text Available A novel power and rate control system model for wireless communication networks is presented, which includes uncertainties, input constraints, and time-varying delays in both state and control input. A robust delay-dependent model predictive power and rate control method is proposed, and the state feedback control law is obtained by solving an optimization problem that is derived by using linear matrix inequality (LMI techniques. Simulation results are given to illustrate the effectiveness of the proposed method.

  2. Prediction of ozone tropospheric degradation rate constant of organic compounds by using artificial neural networks

    International Nuclear Information System (INIS)

    Fatemi, M.H.

    2006-01-01

    Ozone tropospheric degradation of organic compound is very important in environmental chemistry. The lifetime of organic chemicals in the atmosphere can be calculated from the knowledge of the rate constant of their reaction with free radicals such as OH and NO 3 or O 3 . In the present work, the rate constant for the tropospheric degradation of 137 organic compounds by reaction with ozone, the least widely and successfully modeled degradation process, are predicted by quantitative structure activity relationships modeling based on a variety of theoretical descriptors, which screened and selected by genetic algorithm variable subset selection procedure. These descriptors which can be used as inputs for generated artificial neural networks are; HOMO-LUMO gap, number of double bonds, number of single bonds, maximum net charge on C atom, minimum (>0.1) bond order of C atom and Minimum e-e repulsion of H atom. After generation, optimization and training of artificial neural network, network was used for the prediction of log KO 3 for the validation set. The root mean square error for the neural network calculated log KO 3 for training, prediction and validation set are 0.357, 0.460 and 0.481, respectively, which are smaller than those obtained by multiple linear regressions model (1.217, 0.870 and 0.968, respectively). Results obtained reveal the reliability and good predictivity of neural network model for the prediction of ozone tropospheric degradations rate constant of organic compounds

  3. An improved shuffled frog leaping algorithm based evolutionary framework for currency exchange rate prediction

    Science.gov (United States)

    Dash, Rajashree

    2017-11-01

    Forecasting purchasing power of one currency with respect to another currency is always an interesting topic in the field of financial time series prediction. Despite the existence of several traditional and computational models for currency exchange rate forecasting, there is always a need for developing simpler and more efficient model, which will produce better prediction capability. In this paper, an evolutionary framework is proposed by using an improved shuffled frog leaping (ISFL) algorithm with a computationally efficient functional link artificial neural network (CEFLANN) for prediction of currency exchange rate. The model is validated by observing the monthly prediction measures obtained for three currency exchange data sets such as USD/CAD, USD/CHF, and USD/JPY accumulated within same period of time. The model performance is also compared with two other evolutionary learning techniques such as Shuffled frog leaping algorithm and Particle Swarm optimization algorithm. Practical analysis of results suggest that, the proposed model developed using the ISFL algorithm with CEFLANN network is a promising predictor model for currency exchange rate prediction compared to other models included in the study.

  4. Improved predictions of nuclear reaction rates with the TALYS reaction code for astrophysical applications

    International Nuclear Information System (INIS)

    Goriely, S.; Hilaire, S.; Koning, A.J

    2008-01-01

    Context. Nuclear reaction rates of astrophysical applications are traditionally determined on the basis of Hauser-Feshbach reaction codes. These codes adopt a number of approximations that have never been tested, such as a simplified width fluctuation correction, the neglect of delayed or multiple-particle emission during the electromagnetic decay cascade, or the absence of the pre-equilibrium contribution at increasing incident energies. Aims. The reaction code TALYS has been recently updated to estimate the Maxwellian-averaged reaction rates that are of astrophysical relevance. These new developments enable the reaction rates to be calculated with increased accuracy and reliability and the approximations of previous codes to be investigated. Methods. The TALYS predictions for the thermonuclear rates of relevance to astrophysics are detailed and compared with those derived by widely-used codes for the same nuclear ingredients. Results. It is shown that TALYS predictions may differ significantly from those of previous codes, in particular for nuclei for which no or little nuclear data is available. The pre-equilibrium process is shown to influence the astrophysics rates of exotic neutron-rich nuclei significantly. For the first time, the Maxwellian- averaged (n, 2n) reaction rate is calculated for all nuclei and its competition with the radiative capture rate is discussed. Conclusions. The TALYS code provides a new tool to estimate all nuclear reaction rates of relevance to astrophysics with improved accuracy and reliability. (authors)

  5. A prediction method for the wax deposition rate based on a radial basis function neural network

    Directory of Open Access Journals (Sweden)

    Ying Xie

    2017-06-01

    Full Text Available The radial basis function neural network is a popular supervised learning tool based on machinery learning technology. Its high precision having been proven, the radial basis function neural network has been applied in many areas. The accumulation of deposited materials in the pipeline may lead to the need for increased pumping power, a decreased flow rate or even to the total blockage of the line, with losses of production and capital investment, so research on predicting the wax deposition rate is significant for the safe and economical operation of an oil pipeline. This paper adopts the radial basis function neural network to predict the wax deposition rate by considering four main influencing factors, the pipe wall temperature gradient, pipe wall wax crystal solubility coefficient, pipe wall shear stress and crude oil viscosity, by the gray correlational analysis method. MATLAB software is employed to establish the RBF neural network. Compared with the previous literature, favorable consistency exists between the predicted outcomes and the experimental results, with a relative error of 1.5%. It can be concluded that the prediction method of wax deposition rate based on the RBF neural network is feasible.

  6. USE OF ROUGH SETS AND SPECTRAL DATA FOR BUILDING PREDICTIVE MODELS OF REACTION RATE CONSTANTS

    Science.gov (United States)

    A model for predicting the log of the rate constants for alkaline hydrolysis of organic esters has been developed with the use of gas-phase min-infrared library spectra and a rule-building software system based on the mathematical theory of rough sets. A diverse set of 41 esters ...

  7. Looking Maori predicts decreased rates of home ownership : Institutional racism in housing based on perceived appearance

    NARCIS (Netherlands)

    Houkamau, C.A.; Sibley, C.G.

    2015-01-01

    This study examined differences in rates of home ownership among Māori (the indigenous peoples of New Zealand). We identified systematic factors that predicted why some Māori were more likely to own their own home (partially or fully) relative to other Māori. Data were drawn from a large national

  8. Packetized Predictive Control for Rate-Limited Networks via Sparse Representation

    DEFF Research Database (Denmark)

    Nagahara, Masaaki; Quevedo, Daniel; Østergaard, Jan

    2012-01-01

    controller and the plant input. To achieve robustness with respect to dropouts, the controller transmits data packets containing plant input predictions, which minimize a finite horizon cost function. In our formulation, we design sparse packets for rate-limited networks, by adopting an an ℓ0 optimization...

  9. Resting-state qEEG predicts rate of second language learning in adults.

    Science.gov (United States)

    Prat, Chantel S; Yamasaki, Brianna L; Kluender, Reina A; Stocco, Andrea

    2016-01-01

    Understanding the neurobiological basis of individual differences in second language acquisition (SLA) is important for research on bilingualism, learning, and neural plasticity. The current study used quantitative electroencephalography (qEEG) to predict SLA in college-aged individuals. Baseline, eyes-closed resting-state qEEG was used to predict language learning rate during eight weeks of French exposure using an immersive, virtual scenario software. Individual qEEG indices predicted up to 60% of the variability in SLA, whereas behavioral indices of fluid intelligence, executive functioning, and working-memory capacity were not correlated with learning rate. Specifically, power in beta and low-gamma frequency ranges over right temporoparietal regions were strongly positively correlated with SLA. These results highlight the utility of resting-state EEG for studying the neurobiological basis of SLA in a relatively construct-free, paradigm-independent manner. Published by Elsevier Inc.

  10. Comparison between experimental and predicted specific absorption rate of functionalized iron oxide nanoparticle suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Yuan Yuan [Mechanical, Aerospace and Nuclear Engineering Department Rensselaer Polytechnic Institute, Troy, NY 12180 (United States); Tasciuc, Diana-Andra Borca, E-mail: borcad@rpi.edu [Mechanical, Aerospace and Nuclear Engineering Department Rensselaer Polytechnic Institute, Troy, NY 12180 (United States)

    2011-10-15

    Radio-frequency heated magnetic nanoaparticle suspensions have potential applications in cancer hyperthermia. To optimize these systems for hyperthermia applications it is important to be able to predict how their heat generation or specific absorption rate (SAR) is influenced by various factors, including nanoparticle coating or functionalization and aggregation. However, at present it is unclear how well-existing models predict experimental SAR results. Direct comparisons between predicted and measured SAR are scarce, despite an abundance of works reporting on heat generation rate of various magnetic nanoparticles suspensions. The main objective of this paper is to experimentally assess the validity of current models for SAR and extract information on the effects of coating and aggregation on heat generation rate. In this context, AC susceptibility and magnetization of suspensions of uncoated particles, as well as particles with aminosilane and carboxymethyl-dextran functionalizations, were measured. These properties were then used to predict the heat generation rate in alternating magnetic field starting from first principles, which was then compared to measured SAR. It was found that experimental SAR agrees relatively well with predictions (by a factor of two) when using experimental susceptibility values for the SAR calculation. However, for uncoated and amine-functionalized particles poor agreement (more than an order of magnitude difference) was found when the experimental susceptibility was substituted with predictions based on the Debye model. This apparent discrepancy is attributed to dipolar interactions between nanoparticles within aggregates in these samples, which enhances the imaginary part of the susceptibility and, consequently, the SAR values. The results also suggest that the thermal resistance effect of the coating has little influence on the SAR. - Highlights: > Thermal resistance of nanoparticle coating has little impact on heat dissipation

  11. Supply Chain Model with Stochastic Lead Time, Trade-Credit Financing, and Transportation Discounts

    Directory of Open Access Journals (Sweden)

    Sung Jun Kim

    2017-01-01

    Full Text Available This model extends a two-echelon supply chain model by considering the trade-credit policy, transportations discount to make a coordination mechanism between transportation discounts, trade-credit financing, number of shipments, quality improvement of products, and reduced setup cost in such a way that the total cost of the whole system can be reduced, where the supplier offers trade-credit-period to the buyer. For buyer, the backorder rate is considered as variable. There are two investments to reduce setup cost and to improve quality of products. The model assumes lead time-dependent backorder rate, where the lead time is stochastic in nature. By using the trade-credit policy, the model gives how the credit-period would be determined to achieve the win-win outcome. An iterative algorithm is designed to obtain the global optimum results. Numerical example and sensitivity analysis are given to illustrate the model.

  12. Predictive Validity of the Columbia-Suicide Severity Rating Scale for Short-Term Suicidal Behavior

    DEFF Research Database (Denmark)

    Conway, Paul Maurice; Erlangsen, Annette; Teasdale, Thomas William

    2017-01-01

    adolescents (90.6% females) who participated at follow-up (85.9%) out of the 99 (49.7%) baseline respondents. All adolescents were recruited from a specialized suicide-prevention clinic in Denmark. Through multivariate logistic regression analyses, we examined whether baseline suicidal behavior predicted......Using the Columbia-Suicide Severity Rating Scale (C-SSRS), we examined the predictive and incremental predictive validity of past-month suicidal behavior and ideation for short-term suicidal behavior among adolescents at high risk of suicide. The study was conducted in 2014 on a sample of 85...... subsequent suicidal behavior (actual attempts and suicidal behavior of any type, including preparatory acts, aborted, interrupted and actual attempts; mean follow-up of 80.8 days, SD = 52.4). Furthermore, we examined whether suicidal ideation severity and intensity incrementally predicted suicidal behavior...

  13. Predictive power of the DASA-IV: Variations in rating method and timescales.

    Science.gov (United States)

    Nqwaku, Mphindisi; Draycott, Simon; Aldridge-Waddon, Luke; Bush, Emma-Louise; Tsirimokou, Alexandra; Jones, Dominic; Puzzo, Ignazio

    2018-05-10

    This project evaluated the predictive validity of the Dynamic Appraisal of Situational Aggression - Inpatient Version (DASA-IV) in a high-secure psychiatric hospital in the UK over 24 hours and over a single nursing shift. DASA-IV scores from three sequential nursing shifts over a 24-hour period were compared with the mean (average of three scores across the 24-hour period) and peak (highest of the three scores across the 24-hour period) scores across these shifts. In addition, scores from a single nursing shift were used to predict aggressive incidents over each of the following three shifts. The DASA-IV was completed by nursing staff during handover meetings, rating 43 male psychiatric inpatients over a period of 6 months. Data were compared to incident reports recorded over the same period. Receiver operating characteristic (ROC) curves and generalized estimating equations assessed the predictive ability of various DASA-IV scores over 24-hour and single-shift timescales. Scores from the DASA-IV based on a single shift had moderate predictive ability for aggressive incidents occurring the next calendar day, whereas scores based on all three shifts had excellent predictive ability. DASA-IV scores from a single shift showed moderate predictive ability for each of the following three shifts. The DASA-IV has excellent predictive ability for aggressive incidents within a secure setting when data are summarized over a 24-hour period, as opposed to when a single rating is taken. In addition, it has moderate value for predicting incidents over even shorter timescales. © 2018 Australian College of Mental Health Nurses Inc.

  14. Exchange rate prediction with multilayer perceptron neural network using gold price as external factor

    Directory of Open Access Journals (Sweden)

    Mohammad Fathian

    2012-04-01

    Full Text Available In this paper, the problem of predicting the exchange rate time series in the foreign exchange rate market is going to be solved using a time-delayed multilayer perceptron neural network with gold price as external factor. The input for the learning phase of the artificial neural network are the exchange rate data of the last five days plus the gold price in two different currencies of the exchange rate as the external factor for helping the artificial neural network improving its forecast accuracy. The five-day delay has been chosen because of the weekly cyclic behavior of the exchange rate time series with the consideration of two holidays in a week. The result of forecasts are then compared with using the multilayer peceptron neural network without gold price external factor by two most important evaluation techniques in the literature of exchange rate prediction. For the experimental analysis phase, the data of three important exchange rates of EUR/USD, GBP/USD, and USD/JPY are used.

  15. Mathematical model for predicting molecular-beam epitaxy growth rates for wafer production

    International Nuclear Information System (INIS)

    Shi, B.Q.

    2003-01-01

    An analytical mathematical model for predicting molecular-beam epitaxy (MBE) growth rates is reported. The mathematical model solves the mass-conservation equation for liquid sources in conical crucibles and predicts the growth rate by taking into account the effect of growth source depletion on the growth rate. Assumptions made for deducing the analytical model are discussed. The model derived contains only one unknown parameter, the value of which can be determined by using data readily available to MBE growers. Procedures are outlined for implementing the model in MBE production of III-V compound semiconductor device wafers. Results from use of the model to obtain targeted layer compositions and thickness of InP-based heterojunction bipolar transistor wafers are presented

  16. Vigorous physical activity predicts higher heart rate variability among younger adults.

    Science.gov (United States)

    May, Richard; McBerty, Victoria; Zaky, Adam; Gianotti, Melino

    2017-06-14

    Baseline heart rate variability (HRV) is linked to prospective cardiovascular health. We tested intensity and duration of weekly physical activity as predictors of heart rate variability in young adults. Time and frequency domain indices of HRV were calculated based on 5-min resting electrocardiograms collected from 82 undergraduate students. Hours per week of both moderate and vigorous activity were estimated using the International Physical Activity Questionnaire. In regression analyses, hours of vigorous physical activity, but not moderate activity, significantly predicted greater time domain and frequency domain indices of heart rate variability. Adjusted for weekly frequency, greater daily duration of vigorous activity failed to predict HRV indices. Future studies should test direct measurements of vigorous activity patterns as predictors of autonomic function in young adulthood.

  17. A numerical evaluation of prediction accuracy of CO2 absorber model for various reaction rate coefficients

    Directory of Open Access Journals (Sweden)

    Shim S.M.

    2012-01-01

    Full Text Available The performance of the CO2 absorber column using mono-ethanolamine (MEA solution as chemical solvent are predicted by a One-Dimensional (1-D rate based model in the present study. 1-D Mass and heat balance equations of vapor and liquid phase are coupled with interfacial mass transfer model and vapor-liquid equilibrium model. The two-film theory is used to estimate the mass transfer between the vapor and liquid film. Chemical reactions in MEA-CO2-H2O system are considered to predict the equilibrium pressure of CO2 in the MEA solution. The mathematical and reaction kinetics models used in this work are calculated by using in-house code. The numerical results are validated in the comparison of simulation results with experimental and simulation data given in the literature. The performance of CO2 absorber column is evaluated by the 1-D rate based model using various reaction rate coefficients suggested by various researchers. When the rate of liquid to gas mass flow rate is about 8.3, 6.6, 4.5 and 3.1, the error of CO2 loading and the CO2 removal efficiency using the reaction rate coefficients of Aboudheir et al. is within about 4.9 % and 5.2 %, respectively. Therefore, the reaction rate coefficient suggested by Aboudheir et al. among the various reaction rate coefficients used in this study is appropriate to predict the performance of CO2 absorber column using MEA solution. [Acknowledgement. This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF, funded by the Ministry of Education, Science and Technology (2011-0017220].

  18. How to predict a high rate of inappropriateness for upper endoscopy in an endoscopic centre?

    Science.gov (United States)

    Buri, L; Bersani, G; Hassan, C; Anti, M; Bianco, M A; Cipolletta, L; Di Giulio, E; Di Matteo, G; Familiari, L; Ficano, L; Loriga, P; Morini, S; Pietropaolo, V; Zambelli, A; Grossi, E; Intraligi, M; Tessari, F; Buscema, M

    2010-09-01

    Inappropriateness of upper endoscopy (EGD) indication causes decreased diagnostic yield. Our aim of was to identify predictors of appropriateness rate for EGD among endoscopic centres. A post-hoc analysis of two multicentre cross-sectional studies, including 6270 and 8252 patients consecutively referred to EGD in 44 (group A) and 55 (group B) endoscopic Italian centres in 2003 and 2007, respectively, was performed. A multiple forward stepwise regression was applied to group A, and independently validated in group B. A <70% threshold was adopted to define inadequate appropriateness rate clustered by centre. discrete variability of clustered appropriateness rates among the 44 group A centres was observed (median: 77%; range: 41-97%), and a <70% appropriateness rate was detected in 11 (25%). Independent predictors of centre appropriateness rate were: percentage of patients referred by general practitioners (GP), rate of urgent examinations, prevalence of relevant diseases, and academic status. For group B, sensitivity, specificity and area under receiver operating characteristic curve of the model in detecting centres with a <70% appropriateness rate were 54%, 93% and 0.72, respectively. A simple predictive rule, based on rate of patients referred by GPs, rate of urgent examinations, prevalence of relevant diseases and academic status, identified a small subset of centres characterised by a high rate of inappropriateness. These centres may be presumed to obtain the largest benefit from targeted educational programs. Copyright (c) 2010 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

  19. EOQ model for perishable products with price-dependent demand, pre and post discounted selling price

    Science.gov (United States)

    Santhi, G.; Karthikeyan, K.

    2017-11-01

    In this article we introduce an economic order quantity model for perishable products like vegetables, fruits, milk, flowers, meat, etc.,with price-dependent demand, pre and post discounted selling price. Here we consider the demand is depending on selling price and deterioration rate is constant. Here we developed mathematical model to determine optimal discounton the unit selling price to maximize total profit. Numerical examples are given for illustrated.

  20. Incomplete information and the closed-end fund discount

    OpenAIRE

    Barone-Adesi, Giovanni; Kim, Youngsoo

    2008-01-01

    We model the closed-end fund discount/premium in a version of Merton’s (1978) asset pricing model with incomplete information. In this economy, investors trade only assets which they “ know about” . The model generates a closed-end fund discount or premium, depending on risk-aversion parameters. The fund share price reverts to the net asset value on open-ending of the fund. The discount/premium is a result of two economic forces: (1) the fund manager’s objective is to maximize expected utilit...

  1. Where do we stand on discounts? - A Danish perspective

    DEFF Research Database (Denmark)

    Bergqvist, Christian

    The dominant undertaking’s ability to award discounts and other loyalty inducing considerations are subject to much ambiguity and many unsettled issues. Despite discounts being a commercial requirement, even for the dominant undertaking, it’s difficult to draw up clear principles, and while...... the approach to non-dominant undertaking’s restriction of competition has been fundamentally recast over the last 20 years, the appraisal of single company behaviour remains more formal and rigid. However, there have recently been indications that some of the same leniency might have been extended to discounts...

  2. Where Do We Stand on Discounts? - A Nordic Perspective

    DEFF Research Database (Denmark)

    Bastida, Vladimir; Ballebye Okholm, Henrik; Pedersen, Torben

    Dominant undertakings’ ability, under competition law, to award discounts and other loyalty inducing considerations are subject to much ambiguity and unsettled issues. Despite discounts being a commercial requirement, even for the dominant undertaking, it is difficult to draw up clear principles....... to dis-counts and unilateral behaviour and in particular the 2017 Court of Justice rul-ing in Intel has reopened the discussions. The objective of this book is to pro-vide guidance on the matter under EU and Nordic competition law and to align these with economic theory....

  3. Reliability prediction system based on the failure rate model for electronic components

    International Nuclear Information System (INIS)

    Lee, Seung Woo; Lee, Hwa Ki

    2008-01-01

    Although many methodologies for predicting the reliability of electronic components have been developed, their reliability might be subjective according to a particular set of circumstances, and therefore it is not easy to quantify their reliability. Among the reliability prediction methods are the statistical analysis based method, the similarity analysis method based on an external failure rate database, and the method based on the physics-of-failure model. In this study, we developed a system by which the reliability of electronic components can be predicted by creating a system for the statistical analysis method of predicting reliability most easily. The failure rate models that were applied are MILHDBK- 217F N2, PRISM, and Telcordia (Bellcore), and these were compared with the general purpose system in order to validate the effectiveness of the developed system. Being able to predict the reliability of electronic components from the stage of design, the system that we have developed is expected to contribute to enhancing the reliability of electronic components

  4. A GPS Satellite Clock Offset Prediction Method Based on Fitting Clock Offset Rates Data

    Directory of Open Access Journals (Sweden)

    WANG Fuhong

    2016-12-01

    Full Text Available It is proposed that a satellite atomic clock offset prediction method based on fitting and modeling clock offset rates data. This method builds quadratic model or linear model combined with periodic terms to fit the time series of clock offset rates, and computes the model coefficients of trend with the best estimation. The clock offset precisely estimated at the initial prediction epoch is directly adopted to calculate the model coefficient of constant. The clock offsets in the rapid ephemeris (IGR provided by IGS are used as modeling data sets to perform certain experiments for different types of GPS satellite clocks. The results show that the clock prediction accuracies of the proposed method for 3, 6, 12 and 24 h achieve 0.43, 0.58, 0.90 and 1.47 ns respectively, which outperform the traditional prediction method based on fitting original clock offsets by 69.3%, 61.8%, 50.5% and 37.2%. Compared with the IGU real-time clock products provided by IGS, the prediction accuracies of the new method have improved about 15.7%, 23.7%, 27.4% and 34.4% respectively.

  5. Islet oxygen consumption rate (OCR) dose predicts insulin independence for first clinical islet allotransplants

    Science.gov (United States)

    Kitzmann, JP; O’Gorman, D; Kin, T; Gruessner, AC; Senior, P; Imes, S; Gruessner, RW; Shapiro, AMJ; Papas, KK

    2014-01-01

    Human islet allotransplant (ITx) for the treatment of type 1 diabetes is in phase III clinical registration trials in the US and standard of care in several other countries. Current islet product release criteria include viability based on cell membrane integrity stains, glucose stimulated insulin release (GSIR), and islet equivalent (IE) dose based on counts. However, only a fraction of patients transplanted with islets that meet or exceed these release criteria become insulin independent following one transplant. Measurements of islet oxygen consumption rate (OCR) have been reported as highly predictive of transplant outcome in many models. In this paper we report on the assessment of clinical islet allograft preparations using islet oxygen consumption rate (OCR) dose (or viable IE dose) and current product release assays in a series of 13 first transplant recipients. The predictive capability of each assay was examined and successful graft function was defined as 100% insulin independence within 45 days post-transplant. Results showed that OCR dose was most predictive of CTO. IE dose was also highly predictive, while GSIR and membrane integrity stains were not. In conclusion, OCR dose can predict CTO with high specificity and sensitivity and is a useful tool for evaluating islet preparations prior to clinical ITx. PMID:25131089

  6. Predicting Basal Metabolic Rate in Men with Motor Complete Spinal Cord Injury.

    Science.gov (United States)

    Nightingale, Tom E; Gorgey, Ashraf S

    2018-01-08

    To assess the accuracy of existing basal metabolic rate (BMR) prediction equations in men with chronic (>1 year) spinal cord injury (SCI). The primary aim is to develop new SCI population-specific BMR prediction models, based on anthropometric, body composition and/or demographic variables that are strongly associated with BMR. Thirty men with chronic SCI (Paraplegic; n = 21, Tetraplegic; n = 9), aged 35 ± 11 years (mean ± SD) participated in this cross-sectional study. Criterion BMR values were measured by indirect calorimetry. Body composition (dual energy X-ray absorptiometry; DXA) and anthropometric measurements (circumferences and diameters) were also taken. Multiple linear regression analysis was performed to develop new SCI-specific BMR prediction models. Criterion BMR values were compared to values estimated from six existing and four developed prediction equations RESULTS: Existing equations that use information on stature, weight and/or age, significantly (P BMR by a mean of 14-17% (187-234 kcal/day). Equations that utilised fat-free mass (FFM) accurately predicted BMR. The development of new SCI-specific prediction models demonstrated that the addition of anthropometric variables (weight, height and calf circumference) to FFM (Model 3; r = 0.77), explained 8% more of the variance in BMR than FFM alone (Model 1; r = 0.69). Using anthropometric variables, without FFM, explained less of the variance in BMR (Model 4; r = 0.57). However, all the developed prediction models demonstrated acceptable mean absolute error ≤ 6%. BMR can be more accurately estimated when DXA derived FFM is incorporated into prediction equations. Utilising anthropometric measurements provides a promising alternative to improve the prediction of BMR, beyond that achieved by existing equations in persons with SCI.

  7. Validity of predictive equations for basal metabolic rate in Japanese adults.

    Science.gov (United States)

    Miyake, Rieko; Tanaka, Shigeho; Ohkawara, Kazunori; Ishikawa-Takata, Kazuko; Hikihara, Yuki; Taguri, Emiko; Kayashita, Jun; Tabata, Izumi

    2011-01-01

    Many predictive equations for basal metabolic rate (BMR) based on anthropometric measurements, age, and sex have been developed, mainly for healthy Caucasians. However, it has been reported that many of these equations, used widely, overestimate BMR not only for Asians, but also for Caucasians. The present study examined the accuracy of several predictive equations for BMR in Japanese subjects. In 365 healthy Japanese male and female subjects, aged 18 to 79 y, BMR was measured in the post-absorptive state using a mask and Douglas bag. Six predictive equations were examined. Total error was used as an index of the accuracy of each equation's prediction. Predicted BMR values by Dietary Reference Intakes for Japanese (Japan-DRI), Adjusted Dietary Reference Intakes for Japanese (Adjusted-DRI), and Ganpule equations were not significantly different from the measured BMR in either sex. On the other hand, Harris-Benedict, Schofield, and Food and Agriculture Organization of the United Nations/World Health Organization/United Nations University equations were significantly higher than the measured BMR in both sexes. The prediction error by Japan-DRI, Adjusted-DRI, and Harris-Benedict equations was significantly correlated with body weight in both sexes. Total error using the Ganpule equation was low in both males and females (125 and 99 kcal/d, respectively). In addition, total error using the Adjusted-DRI equation was low in females (95 kcal/d). Thus, the Ganpule equation was the most accurate in predicting BMR in our healthy Japanese subjects, because the difference between the predicted and measured BMR was relatively small, and body weight had no effect on the prediction error.

  8. Prediction of work metabolism from heart rate measurements in forest work: some practical methodological issues.

    Science.gov (United States)

    Dubé, Philippe-Antoine; Imbeau, Daniel; Dubeau, Denise; Auger, Isabelle; Leone, Mario

    2015-01-01

    Individual heart rate (HR) to workload relationships were determined using 93 submaximal step-tests administered to 26 healthy participants attending physical activities in a university training centre (laboratory study) and 41 experienced forest workers (field study). Predicted maximum aerobic capacity (MAC) was compared to measured MAC from a maximal treadmill test (laboratory study) to test the effect of two age-predicted maximum HR Equations (220-age and 207-0.7 × age) and two clothing insulation levels (0.4 and 0.91 clo) during the step-test. Work metabolism (WM) estimated from forest work HR was compared against concurrent work V̇O2 measurements while taking into account the HR thermal component. Results show that MAC and WM can be accurately predicted from work HR measurements and simple regression models developed in this study (1% group mean prediction bias and up to 25% expected prediction bias for a single individual). Clothing insulation had no impact on predicted MAC nor age-predicted maximum HR equations. Practitioner summary: This study sheds light on four practical methodological issues faced by practitioners regarding the use of HR methodology to assess WM in actual work environments. More specifically, the effect of wearing work clothes and the use of two different maximum HR prediction equations on the ability of a submaximal step-test to assess MAC are examined, as well as the accuracy of using an individual's step-test HR to workload relationship to predict WM from HR data collected during actual work in the presence of thermal stress.

  9. Discounting in agro-industrial complex. A methodological proposal for risk premium

    Directory of Open Access Journals (Sweden)

    Inmaculada Marques-Perez

    2017-04-01

    Full Text Available The estimation of the discount rate is decisive for a reliable economic valuation. The discount rate has to be adjusted for the risks related to the company, the sector which the company has its market, and the risks related to the investment project. We present a proposal to incorporate the risk premium to the discount rate. The novelty of the methodology is that difference risk groups according to activity as a factor to adjust the cost of capital to companies. The study applies the methodology to the Agro-Industrial Complex (AIC in Spain. The AIC is formed by industries that add value to farming production. This sector’s economic success demands financial management techniques that assess risk. The conventional method responds neither to the heterogeneity of the economic activities that make up the AIC, nor to differentiating risk by groups. The proposed methodology distinguishes activity groups in accordance with the NACE (National Code of Economic Activities and uses net profitability variability to distinguish the risk in each group. Our results demonstrate the various levels of risk per group. The results show that among all the groups that form the AIC there are wide differences between levels of risk; thus, the risk neutral groups present risk levels on the order of 150 times lower than the groups extreme risk levels.

  10. Discounting in agro-industrial complex. A methodological proposal for risk premium

    Energy Technology Data Exchange (ETDEWEB)

    Marques-Perez, I.; Guaita-Pradas, I.; Pérez-Salas, J.L.

    2017-09-01

    The estimation of the discount rate is decisive for a reliable economic valuation. The discount rate has to be adjusted for the risks related to the company, the sector which the company has its market, and the risks related to the investment project. We present a proposal to incorporate the risk premium to the discount rate. The novelty of the methodology is that difference risk groups according to activity as a factor to adjust the cost of capital to companies. The study applies the methodology to the Agro-Industrial Complex (AIC) in Spain. The AIC is formed by industries that add value to farming production. This sector’s economic success demands financial management techniques that assess risk. The conventional method responds neither to the heterogeneity of the economic activities that make up the AIC, nor to differentiating risk by groups. The proposed methodology distinguishes activity groups in accordance with the NACE (National Code of Economic Activities) and uses net profitability variability to distinguish the risk in each group. Our results demonstrate the various levels of risk per group. The results show that among all the groups that form the AIC there are wide differences between levels of risk; thus, the risk neutral groups present risk levels on the order of 150 times lower than the groups extreme risk levels.

  11. Discounting in agro-industrial complex. A methodological proposal for risk premium

    International Nuclear Information System (INIS)

    Marques-Perez, I.; Guaita-Pradas, I.; Pérez-Salas, J.L.

    2017-01-01

    The estimation of the discount rate is decisive for a reliable economic valuation. The discount rate has to be adjusted for the risks related to the company, the sector which the company has its market, and the risks related to the investment project. We present a proposal to incorporate the risk premium to the discount rate. The novelty of the methodology is that difference risk groups according to activity as a factor to adjust the cost of capital to companies. The study applies the methodology to the Agro-Industrial Complex (AIC) in Spain. The AIC is formed by industries that add value to farming production. This sector’s economic success demands financial management techniques that assess risk. The conventional method responds neither to the heterogeneity of the economic activities that make up the AIC, nor to differentiating risk by groups. The proposed methodology distinguishes activity groups in accordance with the NACE (National Code of Economic Activities) and uses net profitability variability to distinguish the risk in each group. Our results demonstrate the various levels of risk per group. The results show that among all the groups that form the AIC there are wide differences between levels of risk; thus, the risk neutral groups present risk levels on the order of 150 times lower than the groups extreme risk levels.

  12. A Reduction in Delay Discounting by Using Episodic Future Imagination and the Association with Episodic Memory Capacity.

    Science.gov (United States)

    Hu, Xiaochen; Kleinschmidt, Helena; Martin, Jason A; Han, Ying; Thelen, Manuela; Meiberth, Dix; Jessen, Frank; Weber, Bernd

    2016-01-01

    Delay discounting (DD) refers to the phenomenon that individuals discount future consequences. Previous studies showed that future imagination reduces DD, which was mediated by functional connectivity between medial prefrontal valuation areas and a key region for episodic memory (hippocampus). Future imagination involves an initial period of construction and a later period of elaboration, with the more elaborative latter period recruiting more cortical regions. This study examined whether elaborative future imagination modulated DD, and if so, what are the underlying neural substrates. It was assumed that cortical areas contribute to the modulation effect during the later period of imagination. Since future imagination is supported by episodic memory capacity, we additionally hypothesize that the neural network underlying the modulation effect is related to individual episodic memory capacity. Twenty-two subjects received an extensive interview on personal future events, followed by an fMRI DD experiment with and without the need to perform elaborative future imagination simultaneously. Subjects' episodic memory capacity was also assessed. Behavioral results replicate previous findings of a reduced discount rate in the DD plus imagination condition compared to the DD only condition. The behavioral effect positively correlated with: (i) subjective value signal changes in midline brain structures during the initial imagination period; and (ii) signal changes in left prefrontoparietal areas during the later imagination period. Generalized psychophysiological interaction (gPPI) analyses reveal positive correlations between the behavioral effect and functional connectivity among the following areas: right anterior cingulate cortex (ACC) and left hippocampus; left inferior parietal cortex (IPC) and left hippocampus; and left IPC and bilateral occipital cortices. These changes in functional connectivity are also associated with episodic memory capacity. A hierarchical

  13. Heart rate during basketball game play and volleyball drills accurately predicts oxygen uptake and energy expenditure.

    Science.gov (United States)

    Scribbans, T D; Berg, K; Narazaki, K; Janssen, I; Gurd, B J

    2015-09-01

    There is currently little information regarding the ability of metabolic prediction equations to accurately predict oxygen uptake and exercise intensity from heart rate (HR) during intermittent sport. The purpose of the present study was to develop and, cross-validate equations appropriate for accurately predicting oxygen cost (VO2) and energy expenditure from HR during intermittent sport participation. Eleven healthy adult males (19.9±1.1yrs) were recruited to establish the relationship between %VO2peak and %HRmax during low-intensity steady state endurance (END), moderate-intensity interval (MOD) and high intensity-interval exercise (HI), as performed on a cycle ergometer. Three equations (END, MOD, and HI) for predicting %VO2peak based on %HRmax were developed. HR and VO2 were directly measured during basketball games (6 male, 20.8±1.0 yrs; 6 female, 20.0±1.3yrs) and volleyball drills (12 female; 20.8±1.0yrs). Comparisons were made between measured and predicted VO2 and energy expenditure using the 3 equations developed and 2 previously published equations. The END and MOD equations accurately predicted VO2 and energy expenditure, while the HI equation underestimated, and the previously published equations systematically overestimated VO2 and energy expenditure. Intermittent sport VO2 and energy expenditure can be accurately predicted from heart rate data using either the END (%VO2peak=%HRmax x 1.008-17.17) or MOD (%VO2peak=%HRmax x 1.2-32) equations. These 2 simple equations provide an accessible and cost-effective method for accurate estimation of exercise intensity and energy expenditure during intermittent sport.

  14. Earthquake Prediction Analysis Based on Empirical Seismic Rate: The M8 Algorithm

    International Nuclear Information System (INIS)

    Molchan, G.; Romashkova, L.

    2010-07-01

    The quality of space-time earthquake prediction is usually characterized by a two-dimensional error diagram (n,τ), where n is the rate of failures-to-predict and τ is the normalized measure of space-time alarm. The most reasonable space measure for analysis of a prediction strategy is the rate of target events λ(dg) in a sub-area dg. In that case the quantity H = 1-(n +τ) determines the prediction capability of the strategy. The uncertainty of λ(dg) causes difficulties in estimating H and the statistical significance, α, of prediction results. We investigate this problem theoretically and show how the uncertainty of the measure can be taken into account in two situations, viz., the estimation of α and the construction of a confidence zone for the (n,τ)-parameters of the random strategies. We use our approach to analyse the results from prediction of M ≥ 8.0 events by the M8 method for the period 1985-2009 (the M8.0+ test). The model of λ(dg) based on the events Mw ≥ 5.5, 1977-2004, and the magnitude range of target events 8.0 ≤ M < 8.5 are considered as basic to this M8 analysis. We find the point and upper estimates of α and show that they are still unstable because the number of target events in the experiment is small. However, our results argue in favour of non-triviality of the M8 prediction algorithm. (author)

  15. Earthquake prediction analysis based on empirical seismic rate: the M8 algorithm

    Science.gov (United States)

    Molchan, G.; Romashkova, L.

    2010-12-01

    The quality of space-time earthquake prediction is usually characterized by a 2-D error diagram (n, τ), where n is the fraction of failures-to-predict and τ is the local rate of alarm averaged in space. The most reasonable averaging measure for analysis of a prediction strategy is the normalized rate of target events λ(dg) in a subarea dg. In that case the quantity H = 1 - (n + τ) determines the prediction capability of the strategy. The uncertainty of λ(dg) causes difficulties in estimating H and the statistical significance, α, of prediction results. We investigate this problem theoretically and show how the uncertainty of the measure can be taken into account in two situations, viz., the estimation of α and the construction of a confidence zone for the (n, τ)-parameters of the random strategies. We use our approach to analyse the results from prediction of M >= 8.0 events by the M8 method for the period 1985-2009 (the M8.0+ test). The model of λ(dg) based on the events Mw >= 5.5, 1977-2004, and the magnitude range of target events 8.0 <= M < 8.5 are considered as basic to this M8 analysis. We find the point and upper estimates of α and show that they are still unstable because the number of target events in the experiment is small. However, our results argue in favour of non-triviality of the M8 prediction algorithm.

  16. MEDEX 2015: Heart Rate Variability Predicts Development of Acute Mountain Sickness.

    Science.gov (United States)

    Sutherland, Angus; Freer, Joseph; Evans, Laura; Dolci, Alberto; Crotti, Matteo; Macdonald, Jamie Hugo

    2017-09-01

    Sutherland, Angus, Joseph Freer, Laura Evans, Alberto Dolci, Matteo Crotti, and Jamie Hugo Macdonald. MEDEX 2015: Heart rate variability predicts development of acute mountain sickness. High Alt Med Biol. 18: 199-208, 2017. Acute mountain sickness (AMS) develops when the body fails to acclimatize to atmospheric changes at altitude. Preascent prediction of susceptibility to AMS would be a useful tool to prevent subsequent harm. Changes to peripheral oxygen saturation (SpO 2 ) on hypoxic exposure have previously been shown to be of poor predictive value. Heart rate variability (HRV) has shown promise in the early prediction of AMS, but its use pre-expedition has not previously been investigated. We aimed to determine whether pre- and intraexpedition HRV assessment could predict susceptibility to AMS at high altitude with better diagnostic accuracy than SpO 2 . Forty-four healthy volunteers undertook an expedition in the Nepali Himalaya to >5000 m. SpO 2 and HRV parameters were recorded at rest in normoxia and in a normobaric hypoxic chamber before the expedition. On the expedition HRV parameters and SpO 2 were collected again at 3841 m. A daily Lake Louise Score was obtained to assess AMS symptomology. Low frequency/high frequency (LF/HF) ratio in normoxia (cutpoint ≤2.28 a.u.) and LF following 15 minutes of exposure to normobaric hypoxia had moderate (area under the curve ≥0.8) diagnostic accuracy. LF/HF ratio in normoxia had the highest sensitivity (85%) and specificity (88%) for predicting AMS on subsequent ascent to altitude. In contrast, pre-expedition SpO 2 measurements had poor (area under the curve <0.7) diagnostic accuracy and inferior sensitivity and specificity. Pre-ascent measurement of HRV in normoxia was found to be of better diagnostic accuracy for AMS prediction than all measures of HRV in hypoxia, and better than peripheral oxygen saturation monitoring.

  17. Improved predictions of nuclear reaction rates for astrophysics applications with the TALYS reaction code

    International Nuclear Information System (INIS)

    Goriely, S.; Hilaire, S.; Koning, A.J.

    2008-01-01

    Nuclear reaction rates for astrophysics applications are traditionally determined on the basis of Hauser-Feshbach reaction codes, like MOST. These codes use simplified schemes to calculate the capture reaction cross section on a given target nucleus, not only in its ground state but also on the different thermally populated states of the stellar plasma at a given temperature. Such schemes include a number of approximations that have never been tested, such as an approximate width fluctuation correction, the neglect of delayed particle emission during the electromagnetic decay cascade or the absence of the pre-equilibrium contribution at increasing incident energies. New developments have been brought to the reaction code TALYS to estimate the Maxwellian-averaged reaction rates of astrophysics relevance. These new developments give us the possibility to calculate with an improved accuracy the reaction cross sections and the corresponding astrophysics rates. The TALYS predictions for the thermonuclear rates of astrophysics relevance are presented and compared with those obtained with the MOST code on the basis of the same nuclear ingredients for nuclear structure properties, optical model potential, nuclear level densities and γ-ray strength. It is shown that, in particular, the pre-equilibrium process significantly influences the astrophysics rates of exotic neutron-rich nuclei. The reciprocity theorem traditionally used in astrophysics to determine photo-rates is also shown no to be valid for exotic nuclei. The predictions obtained with different nuclear inputs are also analyzed to provide an estimate of the theoretical uncertainties still affecting the reaction rate prediction far away from the experimentally known regions. (authors)

  18. Tax revenue and inflation rate predictions in Banda Aceh using Vector Error Correction Model (VECM)

    Science.gov (United States)

    Maulia, Eva; Miftahuddin; Sofyan, Hizir

    2018-05-01

    A country has some important parameters to achieve the welfare of the economy, such as tax revenues and inflation. One of the largest revenues of the state budget in Indonesia comes from the tax sector. Besides, the rate of inflation occurring in a country can be used as one measure, to measure economic problems that the country facing. Given the importance of tax revenue and inflation rate control in achieving economic prosperity, it is necessary to analyze the relationship and forecasting tax revenue and inflation rate. VECM (Vector Error Correction Model) was chosen as the method used in this research, because of the data used in the form of multivariate time series data. This study aims to produce a VECM model with optimal lag and to predict the tax revenue and inflation rate of the VECM model. The results show that the best model for data of tax revenue and the inflation rate in Banda Aceh City is VECM with 3rd optimal lag or VECM (3). Of the seven models formed, there is a significant model that is the acceptance model of income tax. The predicted results of tax revenue and the inflation rate in Kota Banda Aceh for the next 6, 12 and 24 periods (months) obtained using VECM (3) are considered valid, since they have a minimum error value compared to other models.

  19. RSA prediction of high failure rate for the uncoated Interax TKA confirmed by meta-analysis.

    Science.gov (United States)

    Pijls, Bart G; Nieuwenhuijse, Marc J; Schoones, Jan W; Middeldorp, Saskia; Valstar, Edward R; Nelissen, Rob G H H

    2012-04-01

    In a previous radiostereometric (RSA) trial the uncoated, uncemented, Interax tibial components showed excessive migration within 2 years compared to HA-coated and cemented tibial components. It was predicted that this type of fixation would have a high failure rate. The purpose of this systematic review and meta-analysis was to investigate whether this RSA prediction was correct. We performed a systematic review and meta-analysis to determine the revision rate for aseptic loosening of the uncoated and cemented Interax tibial components. 3 studies were included, involving 349 Interax total knee arthroplasties (TKAs) for the comparison of uncoated and cemented fixation. There were 30 revisions: 27 uncoated and 3 cemented components. There was a 3-times higher revision rate for the uncoated Interax components than that for cemented Interax components (OR = 3; 95% CI: 1.4-7.2). This meta-analysis confirms the prediction of a previous RSA trial. The uncoated Interax components showed the highest migration and turned out to have the highest revision rate for aseptic loosening. RSA appears to enable efficient detection of an inferior design as early as 2 years postoperatively in a small group of patients.

  20. Prediction of Soil Erosion Rates in Japan where Heavily Forested Landscape with Unstable Terrain

    Science.gov (United States)

    Nanko, K.; Oguro, M.; Miura, S.; Masaki, T.

    2016-12-01

    Soil is fundamental for plant growth, water conservation, and sustainable forest management. Multidisciplinary interest in the role of the soil in areas such as biodiversity, ecosystem services, land degradation, and water security has been growing (Miura et al., 2015). Forest is usually protective land use from soil erosion because vegetation buffers rainfall power and erosivity. However, some types of forest in Japan show high susceptibility to soil erosion due to little ground cover and steep slopes exceeding thirty degree, especially young Japanese cypress (Chamaecyparis obtusa) plantations (Miura et al., 2002). This is a critical issue for sustainable forest management because C. obtusaplantations account for 10% of the total forest coverage in Japan (Forestry Agency, 2009). Prediction of soil erosion rates on nationwide scale is necessary to make decision for future forest management plan. To predict and map soil erosion rates across Japan, we applied three soil erosion models, RUSLE (Revised Universal Soil Loss Equation, Wischmeier and Smith, 1978), PESERA (Pan-European Soil Erosion Risk Assessment, Kirkby et al., 2003), and RMMF (Revised Morgan-Morgan-Finney, Morgan, 2001). The grid scale is 1-km. RUSLE and PESERA are most widely used erosion models today. RMMF includes interactions between rainfall and vegetation, such as canopy interception and ratio of canopy drainage in throughfall. Evaporated rainwater by canopy interception, generally accounts for 15-20% in annual rainfall, does not contribute soil erosion. Whereas, larger raindrops generated by canopy drainage produced higher splash erosion rates than gross rainfall (Nanko et al., 2008). Therefore, rainfall redistribution process in canopy should be considered to predict soil erosion rates in forested landscape. We compared the results from three erosion models and analyze the importance of environmental factors for the prediction of soil erosion rates. This research was supported by the Environment

  1. Predicting diet and consumption rate differences between and within species using gut ecomorphology.

    Science.gov (United States)

    Griffen, Blaine D; Mosblack, Hallie

    2011-07-01

    1. Rapid environmental changes and pressing human needs to forecast the consequences of environmental change are increasingly driving ecology to become a predictive science. The need for effective prediction requires both the development of new tools and the refocusing of existing tools that may have previously been used primarily for purposes other than prediction. One such tool that historically has been more descriptive in nature is ecomorphology (the study of relationships between ecological roles and morphological adaptations of species and individuals). 2. Here, we examine relationships between diet and gut morphology for 15 species of brachyuran crabs, a group of pervasive and highly successful consumers for which trophic predictions would be highly valuable. 3. We show that patterns in crab stomach volume closely match some predictions of metabolic theory and demonstrate that individual diet differences and associated morphological variation reflect, at least in some instances, individual choice or diet specialization. 4. We then present examples of how stomach volume can be used to predict both the per cent herbivory of brachyuran crabs and the relative consumption rates of individual crabs. © 2011 The Authors. Journal of Animal Ecology © 2011 British Ecological Society.

  2. Per-beam, planar IMRT QA passing rates do not predict clinically relevant patient dose errors

    Energy Technology Data Exchange (ETDEWEB)

    Nelms, Benjamin E.; Zhen Heming; Tome, Wolfgang A. [Canis Lupus LLC and Department of Human Oncology, University of Wisconsin, Merrimac, Wisconsin 53561 (United States); Department of Medical Physics, University of Wisconsin, Madison, Wisconsin 53705 (United States); Departments of Human Oncology, Medical Physics, and Biomedical Engineering, University of Wisconsin, Madison, Wisconsin 53792 (United States)

    2011-02-15

    Purpose: The purpose of this work is to determine the statistical correlation between per-beam, planar IMRT QA passing rates and several clinically relevant, anatomy-based dose errors for per-patient IMRT QA. The intent is to assess the predictive power of a common conventional IMRT QA performance metric, the Gamma passing rate per beam. Methods: Ninety-six unique data sets were created by inducing four types of dose errors in 24 clinical head and neck IMRT plans, each planned with 6 MV Varian 120-leaf MLC linear accelerators using a commercial treatment planning system and step-and-shoot delivery. The error-free beams/plans were used as ''simulated measurements'' (for generating the IMRT QA dose planes and the anatomy dose metrics) to compare to the corresponding data calculated by the error-induced plans. The degree of the induced errors was tuned to mimic IMRT QA passing rates that are commonly achieved using conventional methods. Results: Analysis of clinical metrics (parotid mean doses, spinal cord max and D1cc, CTV D95, and larynx mean) vs IMRT QA Gamma analysis (3%/3 mm, 2/2, 1/1) showed that in all cases, there were only weak to moderate correlations (range of Pearson's r-values: -0.295 to 0.653). Moreover, the moderate correlations actually had positive Pearson's r-values (i.e., clinically relevant metric differences increased with increasing IMRT QA passing rate), indicating that some of the largest anatomy-based dose differences occurred in the cases of high IMRT QA passing rates, which may be called ''false negatives.'' The results also show numerous instances of false positives or cases where low IMRT QA passing rates do not imply large errors in anatomy dose metrics. In none of the cases was there correlation consistent with high predictive power of planar IMRT passing rates, i.e., in none of the cases did high IMRT QA Gamma passing rates predict low errors in anatomy dose metrics or vice versa

  3. Per-beam, planar IMRT QA passing rates do not predict clinically relevant patient dose errors

    International Nuclear Information System (INIS)

    Nelms, Benjamin E.; Zhen Heming; Tome, Wolfgang A.

    2011-01-01

    Purpose: The purpose of this work is to determine the statistical correlation between per-beam, planar IMRT QA passing rates and several clinically relevant, anatomy-based dose errors for per-patient IMRT QA. The intent is to assess the predictive power of a common conventional IMRT QA performance metric, the Gamma passing rate per beam. Methods: Ninety-six unique data sets were created by inducing four types of dose errors in 24 clinical head and neck IMRT plans, each planned with 6 MV Varian 120-leaf MLC linear accelerators using a commercial treatment planning system and step-and-shoot delivery. The error-free beams/plans were used as ''simulated measurements'' (for generating the IMRT QA dose planes and the anatomy dose metrics) to compare to the corresponding data calculated by the error-induced plans. The degree of the induced errors was tuned to mimic IMRT QA passing rates that are commonly achieved using conventional methods. Results: Analysis of clinical metrics (parotid mean doses, spinal cord max and D1cc, CTV D95, and larynx mean) vs IMRT QA Gamma analysis (3%/3 mm, 2/2, 1/1) showed that in all cases, there were only weak to moderate correlations (range of Pearson's r-values: -0.295 to 0.653). Moreover, the moderate correlations actually had positive Pearson's r-values (i.e., clinically relevant metric differences increased with increasing IMRT QA passing rate), indicating that some of the largest anatomy-based dose differences occurred in the cases of high IMRT QA passing rates, which may be called ''false negatives.'' The results also show numerous instances of false positives or cases where low IMRT QA passing rates do not imply large errors in anatomy dose metrics. In none of the cases was there correlation consistent with high predictive power of planar IMRT passing rates, i.e., in none of the cases did high IMRT QA Gamma passing rates predict low errors in anatomy dose metrics or vice versa. Conclusions: There is a lack of correlation between

  4. Beyond Rating Curves: Time Series Models for in-Stream Turbidity Prediction

    Science.gov (United States)

    Wang, L.; Mukundan, R.; Zion, M.; Pierson, D. C.

    2012-12-01

    The New York City Department of Environmental Protection (DEP) manages New York City's water supply, which is comprised of over 20 reservoirs and supplies over 1 billion gallons of water per day to more than 9 million customers. DEP's "West of Hudson" reservoirs located in the Catskill Mountains are unfiltered per a renewable filtration avoidance determination granted by the EPA. While water quality is usually pristine, high volume storm events occasionally cause the reservoirs to become highly turbid. A logical strategy for turbidity control is to temporarily remove the turbid reservoirs from service. While effective in limiting delivery of turbid water and reducing the need for in-reservoir alum flocculation, this strategy runs the risk of negatively impacting water supply reliability. Thus, it is advantageous for DEP to understand how long a particular turbidity event will affect their system. In order to understand the duration, intensity and total load of a turbidity event, predictions of future in-stream turbidity values are important. Traditionally, turbidity predictions have been carried out by applying streamflow observations/forecasts to a flow-turbidity rating curve. However, predictions from rating curves are often inaccurate due to inter- and intra-event variability in flow-turbidity relationships. Predictions can be improved by applying an autoregressive moving average (ARMA) time series model in combination with a traditional rating curve. Since 2003, DEP and the Upstate Freshwater Institute have compiled a relatively consistent set of 15-minute turbidity observations at various locations on Esopus Creek above Ashokan Reservoir. Using daily averages of this data and streamflow observations at nearby USGS gauges, flow-turbidity rating curves were developed via linear regression. Time series analysis revealed that the linear regression residuals may be represented using an ARMA(1,2) process. Based on this information, flow-turbidity regressions with

  5. A social discounting model based on Tsallis’ statistics

    Science.gov (United States)

    Takahashi, Taiki

    2010-09-01

    Social decision making (e.g. social discounting and social preferences) has been attracting attention in economics, econophysics, social physics, behavioral psychology, and neuroeconomics. This paper proposes a novel social discounting model based on the deformed algebra developed in the Tsallis’ non-extensive thermostatistics. Furthermore, it is suggested that this model can be utilized to quantify the degree of consistency in social discounting in humans and analyze the relationships between behavioral tendencies in social discounting and other-regarding economic decision making under game-theoretic conditions. Future directions in the application of the model to studies in econophysics, neuroeconomics, and social physics, as well as real-world problems such as the supply of live organ donations, are discussed.

  6. Welcome to professional courtesy discounts: the medical community's pandora's box.

    Science.gov (United States)

    Winkler, A D

    1998-01-01

    Recent government regulations on fraud and abuse have transformed the tradition of professional courtesy discounts into a legal minefield threatening to explode on the uninformed medical provider. This paper offers an understanding of the issues involved and provider options.

  7. Online Discount Luxury: In Search of Guilty Customers

    Directory of Open Access Journals (Sweden)

    Dr. Nikolai Ostapenko

    2013-07-01

    Full Text Available Discount luxury sites mainly serve as online platform for the “flash sales” method, offering limited-time availability of high fashion, travel, home décor, and culinary bargains to its members. The idea of moving “sample sales” online was first realized on a European website, Vente-Privee.com, which now has more than 13 million customers. Following Gilt’s introduction in the United States, flash sales skyrocketed and led to the launching of many new sites, which have proved popular both with consumers seeking impressive discounts on luxury goods, and with exclusive brands wanting to unload their unsold stock quickly. Recently we found that many of the sites are going through the customer fatigue stage, and their further success requires more than just deep discounts. The article reviews possible new business strategies and models within discount luxury retail segment mainly based upon experience of the Gilt Groupe.

  8. Dual discounting in cost-benefit analysis for environmental impacts

    International Nuclear Information System (INIS)

    Kula, Erhun; Evans, David

    2011-01-01

    Discounting has been a long-established intertemporal efficiency tool in cost-benefit analysis which focuses on project selection at communal level with a view to maximising the social welfare. However, with the relentless growth in environmental stress that, in good parts, stems from investment projects the established criterion in discounting appears to be inadequate especially when environmental issues are taken into consideration. This paper looks at how dual focus on efficiency and sustainability can be achieved by using dual discounting, i.e. discounting environmental benefits separately and differently from other costs and benefits and applies this alternative criterion to an afforestation scheme in the United Kingdom which contains carbon sequestration in addition to timber benefits.

  9. Proliferative retinopathy and proteinuria predict mortality rate in type 1 diabetic patients from Fyn County, Denmark

    DEFF Research Database (Denmark)

    Grauslund, J; Green, A; Sjølie, A K

    2008-01-01

    AIMS/HYPOTHESIS: We evaluated the effect of diabetic retinopathy on 25 year survival rate among a population-based cohort of type 1 diabetic patients from Fyn County, Denmark. METHODS: In 1973 all diabetic patients from Fyn County, Denmark with onset before the age of 30 years as of 1 July 1973...... were identified (n=727). In 1981, only 627 patients were still alive and resident in Denmark. Of these, 573 (91%) participated in a clinical baseline examination, in which diabetic retinopathy was graded and other markers of diabetes measured. Mortality rate was examined in a 25 year follow....../INTERPRETATION: Proliferative retinopathy and proteinuria predict mortality rate in a population-based cohort of type 1 diabetic patients. In combination they act even more strongly. Non-proliferative diabetic retinopathy did not affect survival rate....

  10. Precision Obtained Using an Artificial Neural Network for Predicting the Material Removal Rate in Ultrasonic Machining

    Directory of Open Access Journals (Sweden)

    Gaoyan Zhong

    2017-12-01

    Full Text Available The present study proposes a back propagation artificial neural network (BPANN to provide improved precision for predicting the material removal rate (MRR in ultrasonic machining. The BPANN benefits from the advantage of artificial neural networks (ANNs in dealing with complex input-output relationships without explicit mathematical functions. In our previous study, a conventional linear regression model and improved nonlinear regression model were established for modelling the MRR in ultrasonic machining to reflect the influence of machining parameters on process response. In the present work, we quantitatively compare the prediction precision obtained by the previously proposed regression models and the presently proposed BPANN model. The results of detailed analyses indicate that the BPANN model provided the highest prediction precision of the three models considered. The present work makes a positive contribution to expanding the applications of ANNs and can be considered as a guide for modelling complex problems of general machining.

  11. A Rational Model of the Closed-End Fund Discount

    OpenAIRE

    Jonathan Berk; Richard Stanton

    2004-01-01

    The discount on closed-end funds is widely accepted as proof of investor irrationality. We show,however, that a parsimonious rational model can generate a discount that exhibits many of the characteristics observed in practice. The only required features of the model are that managers have (imperfectly observable) ability to generate excess returns; they sign long-term contracts guaranteeing them a fee each year equal to a fixed fraction of assets under management; and they can leave to earn ...

  12. EWAM: a model for predicting food and water ingestion, and inhalation rates of man

    International Nuclear Information System (INIS)

    Zach, Reto; Barnard, John W.

    1985-09-01

    A computer model, EWAM (Energy, Water and Air Model), has been designed and implemented for predicting food and water ingestion, and inhalation rates of man for use in environmental assessment models. EWAM uses physiological, energetic, nutritional and physical relationships in combination with activity time budgets, and mass and energy balances. The calculated ingestion and inhalation rates are closely related. Various age and sex classes of man are taken into account. EWAM is best described as a deterministic equilibrium or steady-state model, operating on a daily time-scale, with both detailed research and more general assessment model features. The parameters of EWAM are reviewed and suitable values recommended to allow biologically meaningful predictions

  13. Frameworks to monitor and predict rates and resource usage in the ATLAS High Level Trigger

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00219969; The ATLAS collaboration

    2017-01-01

    The ATLAS High Level Trigger Farm consists of around 40,000 CPU cores which filter events at an input rate of up to 100 kHz. A costing framework is built into the high level trigger thus enabling detailed monitoring of the system and allowing for data-driven predictions to be made utilising specialist datasets. An overview is presented in to how ATLAS collects in-situ monitoring data on CPU usage during the trigger execution, and how these data are processed to yield both low level monitoring of individual selection-algorithms and high level data on the overall performance of the farm. For development and prediction purposes, ATLAS uses a special ‘Enhanced Bias’ event selection. This mechanism is explained along with how it is used to profile expected resource usage and output event rate of new physics selections, before they are executed on the actual high level trigger farm.

  14. Comparison of predicted versus measured dose rates for low-level radioactive waste cask shipments

    International Nuclear Information System (INIS)

    Macher, Martin S.

    1992-01-01

    Shippers of low-level radioactive waste must select casks which will provide sufficient shielding to keep dose rates below the federal limit of 10 mr/hr at 2 meters from the vehicle. Chem-Nuclear Systems, Inc. uses a cask selection methodology which is based on shielding analysis code predictions with an additional factor of safety applied to compensate for inhomogeneities in the waste, uncertainties in waste characterization, and inaccuracy in the calculational methods. This proven cask selection methodology is explained and suggested factors of safety are presented based on comparisons of predicted and measured dose rates. A safety factor of 2 is shown to be generally appropriate for relatively homogeneous waste and a safety factor of between 3 and 4 is shown to be generally appropriate for relatively inhomogeneous wastes. (author)

  15. Prediction of critical flow rates through power-operated relief valves

    International Nuclear Information System (INIS)

    Abdollahian, D.; Singh, A.

    1983-01-01

    Existing single-phase and two-phase critical flow models are used to predict the flow rates through the power-operated relief valves tested in the EPRI Safety and Relief Valve test program. For liquid upstream conditions, Homogeneous Equilibrium Model, Moody, Henry-Fauske and Burnell two-phase critical flow models are used for comparison with data. Under steam upstream conditions, the flow rates are predicted either by the single-phase isentropic equations or the Homogeneous Equilibrium Model, depending on the thermodynamic condition of the fluid at the choking plane. The results of the comparisons are used to specify discharge coefficients for different valves under steam and liquid upstream conditions and evaluate the existing approximate critical flow relations for a wide range of subcooled water and steam conditions

  16. Pretreatment Growth Rate Predicts Radiation Response in Vestibular Schwannomas

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Nina N. [Department of Radiation Oncology, Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts (United States); Harvard Medical School, Department of Medicine, Brigham and Women' s Hospital, Boston, Massachusetts (United States); Niemierko, Andrzej [Department of Radiation Oncology, Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts (United States); Larvie, Mykol [Harvard Medical School, Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts (United States); Curtin, Hugh [Harvard Medical School, Department of Radiology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts (United States); Loeffler, Jay S. [Department of Radiation Oncology, Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts (United States); McKenna, Michael J. [Harvard Medical School, Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts (United States); Shih, Helen A., E-mail: hshih@partners.org [Department of Radiation Oncology, Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts (United States)

    2014-05-01

    Purpose: Vestibular schwannomas (VS) are often followed without initial therapeutic intervention because many tumors do not grow and radiation therapy is associated with potential adverse effects. In an effort to determine whether maximizing initial surveillance predicts for later treatment response, the predictive value of preirradiation growth rate of VS on response to radiation therapy was assessed. Methods and Materials: Sixty-four patients with 65 VS were treated with single-fraction stereotactic radiation surgery or fractionated stereotactic radiation therapy. Pre- and postirradiation linear expansion rates were estimated using volumetric measurements on sequential magnetic resonance images (MRIs). In addition, postirradiation tumor volume change was classified as demonstrating shrinkage (ratio of volume on last follow-up MRI to MRI immediately preceding irradiation <80%), stability (ratio 80%-120%), or expansion (ratio >120%). The median pre- and postirradiation follow-up was 20.0 and 27.5 months, respectively. Seven tumors from neurofibromatosis type 2 (NF2) patients were excluded from statistical analyses. Results: In the 58 non-NF2 patients, there was a trend of correlation between pre- and postirradiation volume change rates (slope on linear regression, 0.29; P=.06). Tumors demonstrating postirradiation expansion had a median preirradiation growth rate of 89%/year, and those without postirradiation expansion had a median preirradiation growth rate of 41%/year (P=.02). As the preirradiation growth rate increased, the probability of postirradiation expansion also increased. Overall, 24.1% of tumors were stable, 53.4% experienced shrinkage, and 22.5% experienced expansion. Predictors of no postirradiation tumor expansion included no prior surgery (P=.01) and slower tumor growth rate (P=.02). The control of tumors in NF2 patients was only 43%. Conclusions: Radiation therapy is an effective treatment for VS, but tumors that grow quickly preirradiation may be

  17. Pretreatment Growth Rate Predicts Radiation Response in Vestibular Schwannomas

    International Nuclear Information System (INIS)

    Niu, Nina N.; Niemierko, Andrzej; Larvie, Mykol; Curtin, Hugh; Loeffler, Jay S.; McKenna, Michael J.; Shih, Helen A.

    2014-01-01

    Purpose: Vestibular schwannomas (VS) are often followed without initial therapeutic intervention because many tumors do not grow and radiation therapy is associated with potential adverse effects. In an effort to determine whether maximizing initial surveillance predicts for later treatment response, the predictive value of preirradiation growth rate of VS on response to radiation therapy was assessed. Methods and Materials: Sixty-four patients with 65 VS were treated with single-fraction stereotactic radiation surgery or fractionated stereotactic radiation therapy. Pre- and postirradiation linear expansion rates were estimated using volumetric measurements on sequential magnetic resonance images (MRIs). In addition, postirradiation tumor volume change was classified as demonstrating shrinkage (ratio of volume on last follow-up MRI to MRI immediately preceding irradiation <80%), stability (ratio 80%-120%), or expansion (ratio >120%). The median pre- and postirradiation follow-up was 20.0 and 27.5 months, respectively. Seven tumors from neurofibromatosis type 2 (NF2) patients were excluded from statistical analyses. Results: In the 58 non-NF2 patients, there was a trend of correlation between pre- and postirradiation volume change rates (slope on linear regression, 0.29; P=.06). Tumors demonstrating postirradiation expansion had a median preirradiation growth rate of 89%/year, and those without postirradiation expansion had a median preirradiation growth rate of 41%/year (P=.02). As the preirradiation growth rate increased, the probability of postirradiation expansion also increased. Overall, 24.1% of tumors were stable, 53.4% experienced shrinkage, and 22.5% experienced expansion. Predictors of no postirradiation tumor expansion included no prior surgery (P=.01) and slower tumor growth rate (P=.02). The control of tumors in NF2 patients was only 43%. Conclusions: Radiation therapy is an effective treatment for VS, but tumors that grow quickly preirradiation may be

  18. Prediction of rate of CO2 assimilation of leaf lettuce under low light irradiation during storage

    International Nuclear Information System (INIS)

    Uchino, T.; Harada, F.; Hu, W.

    2003-01-01

    The rate of CO 2 assimilation of leaf lettuce changed with its respiration rate and gas constitution in a storage chamber. The optimum irradiance on the surface of leaf lettuce during storage using low light irradiation can be obtained by the prediction of the rate of CO 2 assimilation. For the above mentioned purpose the following equation were derived. -kd[C]/dt=0.5(1-f)I([C]-Γ/4.5[C]+10.5Γ)-ae -bt where, k: proportional constant (4.87×10 -3 mol⋅m -2 ) [C]: CO 2 concentration (ppm), t: time (h), f: fraction of light not absorbed by chloroplasts (0.23), I: irradiance (μmol⋅m-2⋅s -1 ), Γ: CO 2 compensation point without respiration (21.5ppm), a, b: parameters (0.308μmol⋅m -2 ⋅s -1 , 0.010h -1 ). Calculated values of rate of CO 2 assimilation by the equation agreed well with experimental ones at 3.4 and 6.5μmol⋅m -2 ⋅s -1 of irradiance, so it appeared that the assimilation rate could be sufficiently predicted

  19. Predicting the temporal relationship between soil cesium-137 and erosion rate

    International Nuclear Information System (INIS)

    Kachanoski, R.G.; De Jong, E.

    1984-01-01

    A model was developed that predicts the amount of 137 Cs remaining in soil as a function of time and erosion rate. The model accounts for atmospheric deposition, radioactive decay, tillage dilution, and erosion transport of 137 Cs, as well as seasonal differences in 137 Cs deposition and erosion rates. The model was used to estimate minimum resolution of erosion estimates based on detection limits and accuracy of 137 Cs measurement by gamma spectroscopy, as a function of time and erosion rate. The analysis showed that under Saskatchewan conditions, changes in 137 Cs at a given site can be used to estimate erosion rates between 0.5 and 10 kg m -2 yr -1 with reasonable precision, provided the sampling interval is at least 15 yr. The relationship of fraction of 137 Cs lost vs. erosion as predicted by the model was compared with other methods being used. The model was used to estimate erosion from selected Saskatchewan soils where 137 Cs levels were measured in 1966 and again in 1981. Erosion rates calculated with the model varied from 1 kg m -2 yr -1 for a sandy loam soil in continuous forage to 19 kg m -2 yr -1 for a similar soil in a crop-fallow rotation. Erosion estimates using the model were higher than those calculated by assuming that soil loss was directly proportional to 137 Cs loss, especially when 137 Cs loss was high

  20. Application of long-range order to predict unfolding rates of two-state proteins.

    Science.gov (United States)

    Harihar, B; Selvaraj, S

    2011-03-01

    Predicting the experimental unfolding rates of two-state proteins and models describing the unfolding rates of these proteins is quite limited because of the complexity present in the unfolding mechanism and the lack of experimental unfolding data compared with folding data. In this work, 25 two-state proteins characterized by Maxwell et al. (Protein Sci 2005;14:602–616) using a consensus set of experimental conditions were taken, and the parameter long-range order (LRO) derived from their three-dimensional structures were related with their experimental unfolding rates ln(k(u)). From the total data set of 30 proteins used by Maxwell et al. (Protein Sci 2005;14:602–616), five slow-unfolding proteins with very low unfolding rates were considered to be outliers and were not included in our data set. Except all beta structural class, LRO of both the all-alpha and mixed-class proteins showed a strong inverse correlation of r = -0.99 and -0.88, respectively, with experimental ln(k(u)). LRO shows a correlation of -0.62 with experimental ln(k(u)) for all-beta proteins. For predicting the unfolding rates, a simple statistical method has been used and linear regression equations were developed for individual structural classes of proteins using LRO, and the results obtained showed a better agreement with experimental results. Copyright © 2010 Wiley-Liss, Inc.

  1. A model to predict evaporation rates in habitats used by container-dwelling mosquitoes.

    Science.gov (United States)

    Bartlett-Healy, Kristen; Healy, Sean P; Hamilton, George C

    2011-05-01

    Container-dwelling mosquitoes use a wide variety of container habitats. The bottle cap is often cited as the smallest container habitat used by container species. When containers are small, the habitat conditions can greatly affect evaporation rates that in turn can affect the species dynamics within the container. An evaporation rate model was adapted to predict evaporation rates in mosquito container habitats. In both the laboratory and field, our model was able to predict actual evaporation rates. Examples of how the model may be applied are provided by examining the likelihood of Aedes albopictus (Skuse), Aedes aegypti (L.), and Culex pipiens pipiens (L.) completing their development within small-volume containers under typical environmental conditions and a range of temperatures. Our model suggests that under minimal direct sunlight exposure, both Ae. aegypti and Ae. albopictus could develop within a bottle cap before complete evaporation. Our model shows that under the environmental conditions when a plastic field container was sampled, neither Ae. albopictus or Cx. p. pipiens could complete development in that particular container before the water evaporated. Although rainfall could replenish the habitat, the effects of evaporation would increase larval density, which could in turn further decrease developmental rates.

  2. Resting heart rate variability predicts safety learning and fear extinction in an interoceptive fear conditioning paradigm.

    Directory of Open Access Journals (Sweden)

    Meike Pappens

    Full Text Available This study aimed to investigate whether interindividual differences in autonomic inhibitory control predict safety learning and fear extinction in an interoceptive fear conditioning paradigm. Data from a previously reported study (N = 40 were extended (N = 17 and re-analyzed to test whether healthy participants' resting heart rate variability (HRV - a proxy of cardiac vagal tone - predicts learning performance. The conditioned stimulus (CS was a slight sensation of breathlessness induced by a flow resistor, the unconditioned stimulus (US was an aversive short-lasting suffocation experience induced by a complete occlusion of the breathing circuitry. During acquisition, the paired group received 6 paired CS-US presentations; the control group received 6 explicitly unpaired CS-US presentations. In the extinction phase, both groups were exposed to 6 CS-only presentations. Measures included startle blink EMG, skin conductance responses (SCR and US-expectancy ratings. Resting HRV significantly predicted the startle blink EMG learning curves both during acquisition and extinction. In the unpaired group, higher levels of HRV at rest predicted safety learning to the CS during acquisition. In the paired group, higher levels of HRV were associated with better extinction. Our findings suggest that the strength or integrity of prefrontal inhibitory mechanisms involved in safety- and extinction learning can be indexed by HRV at rest.

  3. Predicting Galaxy Star Formation Rates via the Co-evolution of Galaxies and Halos

    OpenAIRE

    Watson, Douglas F.; Hearin, Andrew P.; Berlind, Andreas A.; Becker, Matthew R.; Behroozi, Peter S.; Skibba, Ramin A.; Reyes, Reinabelle; Zentner, Andrew R.; Bosch, Frank C. van den

    2014-01-01

    In this paper, we test the age matching hypothesis that the star formation rate (SFR) of a galaxy of fixed stellar mass is determined by its dark matter halo formation history, and as such, that more quiescent galaxies reside in older halos. This simple model has been remarkably successful at predicting color-based galaxy statistics at low redshift as measured in the Sloan Digital Sky Survey (SDSS). To further test this method with observations, we present new SDSS measurements of the galaxy ...

  4. PBODL : Parallel Bayesian Online Deep Learning for Click-Through Rate Prediction in Tencent Advertising System

    OpenAIRE

    Liu, Xun; Xue, Wei; Xiao, Lei; Zhang, Bo

    2017-01-01

    We describe a parallel bayesian online deep learning framework (PBODL) for click-through rate (CTR) prediction within today's Tencent advertising system, which provides quick and accurate learning of user preferences. We first explain the framework with a deep probit regression model, which is trained with probabilistic back-propagation in the mode of assumed Gaussian density filtering. Then we extend the model family to a variety of bayesian online models with increasing feature embedding ca...

  5. Temporal discounting and emotional self-regulation in children with attention-deficit/hyperactivity disorder.

    Science.gov (United States)

    Utsumi, Daniel Augusto; Miranda, Mônica Carolina; Muszkat, Mauro

    2016-12-30

    Temporal Discounting (TD) reflects a tendency to discount a reward more deeply the longer its delivery is delayed. TD tasks and behavioral scales have been used to investigate 'hot' executive functions in ADHD. The present study analyzed TD task performance shown by ADHD and control groups for correlations with emotional self-regulation metrics from two scales, the Behavior Rating Inventory of Executive Functions (BRIEF) and the Child Behavior Checklist (CBCL). Children (ages 8-12) with ADHD (n=25) and controls (n=24) were assessed using material rewards (toys) for three types of task: Hypothetical (H); Hypothetical with temporal expectation (HTE); and Real (R). Between-group differences were found for the HTE task, on which the ADHD group showed a higher rate of discounting their favorite toy over time, especially at 10s and 20s. This was the only task on which performance significantly correlated with BRIEF metrics, thus suggesting associations between impulsivity and low emotional self-regulation, but no task was correlated with CBCL score. The conclusion is that tasks involving toys and HTE in particular may be used to investigate TD in children with ADHD and as a means of evaluating the interface between the reward system and emotional self-regulation. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  6. Impairment in delay discounting in schizophrenia and schizoaffective disorder but not primary mood disorders.

    Science.gov (United States)

    Brown, Hannah E; Hart, Kamber L; Snapper, Leslie A; Roffman, Joshua L; Perlis, Roy H

    2018-05-28

    A measure of planning and impulse control, the delay-discounting (DD) task estimates the extent to which an individual decreases the perceived value of a reward as the reward is delayed. We examined cross-disorder performance between healthy controls (n = 88), individuals with bipolar disorder (n = 23), major depressive disorder (n = 43), and primary psychotic disorders (schizophrenia and schizoaffective disorder; n = 51) on the DD task (using a $10 delayed larger reward), as well as the interaction of DD scores with other symptom domains (cognition, psychosis, and affect). We found that individuals with schizophrenia and schizoaffective disorder display significantly greater rates of discounting compared to healthy controls, while individuals with a primary mood disorder do not differ from healthy controls after adjustment for IQ. Further, impairment in working memory is associated with higher discounting rates among individuals with schizophrenia and schizoaffective disorder, but cognitive dysfunction alone does not account for the extent of impairment in DD. Taken together, these results suggest an impaired ability to plan for the future and make adaptive decisions that are specific to individuals with psychotic disorders, and likely related to adverse functional outcomes. More generally, this work demonstrates the presence of variation in impulsivity across major psychiatric illnesses, supporting the use of a trans-diagnostic perspective.

  7. A novel multi-item joint replenishment problem considering multiple type discounts.

    Directory of Open Access Journals (Sweden)

    Ligang Cui

    Full Text Available In business replenishment, discount offers of multi-item may either provide different discount schedules with a single discount type, or provide schedules with multiple discount types. The paper investigates the joint effects of multiple discount schemes on the decisions of multi-item joint replenishment. In this paper, a joint replenishment problem (JRP model, considering three discount (all-unit discount, incremental discount, total volume discount offers simultaneously, is constructed to determine the basic cycle time and joint replenishment frequencies of multi-item. To solve the proposed problem, a heuristic algorithm is proposed to find the optimal solutions and the corresponding total cost of the JRP model. Numerical experiment is performed to test the algorithm and the computational results of JRPs under different discount combinations show different significance in the replenishment cost reduction.

  8. Delay discounting, treatment motivation and treatment retention among substance-dependent individuals attending an in inpatient detoxification program

    NARCIS (Netherlands)

    Stevens, Laura; Verdejo-García, Antonio; Roeyers, Herbert; Goudriaan, Anna E.; Vanderplasschen, Wouter

    2015-01-01

    Recent studies consistently indicate high rates of delay discounting in drug users, which refers to a strong tendency to devaluate delayed rewards. Many addiction treatment programs however, place high demands on the ability to postpone immediate gratification. Therefore, these programs may be

  9. Mass gathering medicine: a predictive model for patient presentation and transport rates.

    Science.gov (United States)

    Arbon, P; Bridgewater, F H; Smith, C

    2001-01-01

    This paper reports on research into the influence of environmental factors (including crowd size, temperature, humidity, and venue type) on the number of patients and the patient problems presenting to first-aid services at large, public events in Australia. Regression models were developed to predict rates of patient presentation and of transportation-to-a-hospital for future mass gatherings. To develop a data set and predictive model that can be applied across venues and types of mass gathering events that is not venue or event specific. Data collected will allow informed event planning for future mass gatherings for which health care services are required. Mass gatherings were defined as public events attended by in excess of 25,000 people. Over a period of 12 months, 201 mass gatherings attended by a combined audience in excess of 12 million people were surveyed throughout Australia. The survey was undertaken by St. John Ambulance Australia personnel. The researchers collected data on the incidence and type of patients presenting for treatment and on the environmental factors that may influence these presentations. A standard reporting format and definition of event geography was employed to overcome the event-specific nature of many previous surveys. There are 11,956 patients in the sample. The patient presentation rate across all event types was 0.992/1,000 attendees, and the transportation-to-hospital rate was 0.027/1,000 persons in attendance. The rates of patient presentations declined slightly as crowd sizes increased. The weather (particularly the relative humidity) was related positively to an increase in the rates of presentations. Other factors that influenced the number and type of patients presenting were the mobility of the crowd, the availability of alcohol, the event being enclosed by a boundary, and the number of patient-care personnel on duty. Three regression models were developed to predict presentation rates at future events. Several

  10. Predicting how altering propagule pressure changes establishment rates of biological invaders across species pools.

    Science.gov (United States)

    Brockerhoff, Eckehard G; Kimberley, Mark; Liebhold, Andrew M; Haack, Robert A; Cavey, Joseph F

    2014-03-01

    Biological invasions resulting from international trade can cause major environmental and economic impacts. Propagule pressure is perhaps the most important factor influencing establishment, although actual arrival rates of species are rarely recorded. Furthermore, the pool of potential invaders includes many species that vary in their arrival rate and establishment potential. Therefore, we stress that it is essential to consider the size and composition of species pools arriving from source regions when estimating probabilities of establishment and effects of pathway infestation rates. To address this, we developed a novel framework and modeling approach to enable prediction of future establishments in relation to changes in arrival rate across entire species pools. We utilized 13 828 border interception records from the United States and New Zealand for 444 true bark beetle (Scolytinae) and longhorned beetle (Cerambycidae) species detected between 1949 and 2008 as proxies for arrival rates to model the relationship between arrival and establishment rates. Nonlinearity in this relationship implies that measures intended to reduce the unintended transport of potential invaders (such as phytosanitary treatments) must be highly effective in order to substantially reduce the rate of future invasions, particularly if trade volumes continue to increase.

  11. MERGERS IN ΛCDM: UNCERTAINTIES IN THEORETICAL PREDICTIONS AND INTERPRETATIONS OF THE MERGER RATE

    International Nuclear Information System (INIS)

    Hopkins, Philip F.; Bundy, Kevin; Wetzel, Andrew; Ma, Chung-Pei; Croton, Darren; Khochfar, Sadegh; Hernquist, Lars; Genel, Shy; Van den Bosch, Frank; Somerville, Rachel S.; Keres, Dusan; Stewart, Kyle; Younger, Joshua D.

    2010-01-01

    Different theoretical methodologies lead to order-of-magnitude variations in predicted galaxy-galaxy merger rates. We examine how this arises and quantify the dominant uncertainties. Modeling of dark matter and galaxy inspiral/merger times contribute factor of ∼2 uncertainties. Different estimates of the halo-halo merger rate, the subhalo 'destruction' rate, and the halo merger rate with some dynamical friction time delay for galaxy-galaxy mergers, agree to within this factor of ∼2, provided proper care is taken to define mergers consistently. There are some caveats: if halo/subhalo masses are not appropriately defined the major-merger rate can be dramatically suppressed, and in models with 'orphan' galaxies and under-resolved subhalos the merger timescale can be severely over-estimated. The dominant differences in galaxy-galaxy merger rates between models owe to the treatment of the baryonic physics. Cosmological hydrodynamic simulations without strong feedback and some older semi-analytic models (SAMs), with known discrepancies in mass functions, can be biased by large factors (∼5) in predicted merger rates. However, provided that models yield a reasonable match to the total galaxy mass function, the differences in properties of central galaxies are sufficiently small to alone contribute small (factor of ∼1.5) additional systematics to merger rate predictions. But variations in the baryonic physics of satellite galaxies in models can also have a dramatic effect on merger rates. The well-known problem of satellite 'over-quenching' in most current SAMs-whereby SAM satellite populations are too efficiently stripped of their gas-could lead to order-of-magnitude under-estimates of merger rates for low-mass, gas-rich galaxies. Models in which the masses of satellites are fixed by observations (or SAMs adjusted to resolve this 'over-quenching') tend to predict higher merger rates, but with factor of ∼2 uncertainties stemming from the uncertainty in those

  12. Time discounting and pain anticipation. Experimental evidence

    Directory of Open Access Journals (Sweden)

    Brañas Garza, Pablo

    2012-03-01

    Full Text Available This paper deals with pain anticipation experienced before medical procedures. our experimental results show that individuals with lower time discount factors are more prone to suffer pain in advance. We provide a framework to rationalize the connection between pain anticipation and impatience. in this set up, more impatient subjects, who only value very near events, mainly take into account the present negative effects of medical procedures (the costs, whereas more patient individuals have a net positive valuation of medical events, given that they are able to value both the cost incurred now and all the benefits to be accrued in the future.

    Este artículo trata de la anticipación del dolor experimentada antes de los procedimientos médicos. nuestros resultados experimentales muestran que los individuos con factor de descuento temporal más bajo son más proclives a sufrir dolor por adelantado. el artículo proporciona un marco en el que racionalizar la relación existente entre impaciencia y anticipación del dolor. en este marco, los sujetos más impacientes, que evalúan sólo los eventos muy próximos en el tiempo, focalizan su atención principalmente en los efectos negativos de los procedimientos médicos (sólo los costes, mientras que los individuos más pacientes tienen una valoración neta positiva de los actos médicos puesto que valoran tanto el coste en el que se incurre en el presente como los beneficios que se obtendrán en el futuro.

  13. On the adequacy of wall functions to predict condensation rates from steam-noncondensable gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Dehbi, A., E-mail: abdel.dehbi@psi.ch

    2013-12-15

    Highlights: • Work investigates the effect of near-wall mesh resolution on CFD predictions. • Case study: turbulent condensation in the presence of noncondensable gases. • Wall functions largely underpredict condensation rates at boundary layer onset. • When boundary layer is developed, wall functions predictions are reasonable. • Prescribed wall functions must be compatible with prevailing flow regime. - Abstract: As one looks forward to applying CFD based methods to simulate turbulent flows in larger volumes up to containment scales, the mesh resolution, especially near the walls, becomes one of the main issues dictating the feasibility of the simulation. The wall-function approach is a natural choice to minimize the computational size of the problem and make it tractable. In the current investigation, we compare the wall-function to the fully resolved boundary layer approaches for the prediction of vapor condensation rates on cold walls in the presence of noncondensable gases. We simulate three sets of geometric configurations. The first two sets relate to domains which are small (height of 2 m) and medium (height 4.8 m), and for which experimental heat transfer data are available. In the third set, we look at a hypothetical large 2D rectangular domain in which the condenser height is comparable to that of typical NPP containments (20 m). In the developing region of the boundary layer, it is found that the wall function treatment leads to substantial deviations from the wall resolved approach and available experimental data. Further downstream, however, when the boundary layer is fully developed, the discrepancy is greatly reduced. It is therefore concluded that the wall-function formulation is able to provide predictions of condensation rates that are similar to wall-resolved treatments in simple forced flows for which fully developed boundary layers can be assumed over most of the domain. Care must however be exercised to ensure the chosen wall

  14. Predicting protein folding rate change upon point mutation using residue-level coevolutionary information.

    Science.gov (United States)

    Mallik, Saurav; Das, Smita; Kundu, Sudip

    2016-01-01

    Change in folding kinetics of globular proteins upon point mutation is crucial to a wide spectrum of biological research, such as protein misfolding, toxicity, and aggregations. Here we seek to address whether residue-level coevolutionary information of globular proteins can be informative to folding rate changes upon point mutations. Generating residue-level coevolutionary networks of globular proteins, we analyze three parameters: relative coevolution order (rCEO), network density (ND), and characteristic path length (CPL). A point mutation is considered to be equivalent to a node deletion of this network and respective percentage changes in rCEO, ND, CPL are found linearly correlated (0.84, 0.73, and -0.61, respectively) with experimental folding rate changes. The three parameters predict the folding rate change upon a point mutation with 0.031, 0.045, and 0.059 standard errors, respectively. © 2015 Wiley Periodicals, Inc.

  15. Prediction of corrosion rates of water distribution pipelines according to aggressive corrosive water in Korea.

    Science.gov (United States)

    Chung, W S; Yu, M J; Lee, H D

    2004-01-01

    The drinking water network serving Korea has been used for almost 100 years. Therefore, pipelines have suffered various degrees of deterioration due to aggressive environments. The pipe breaks were caused by in-external corrosion, water hammer, surface loading, etc. In this paper, we focused on describing corrosion status in water distribution pipes in Korea and reviewing some methods to predict corrosion rates. Results indicate that corrosive water of lakes was more aggressive than river water and the winter was more aggressive compared to other seasons. The roughness growth rates of Dongbok lake showed 0.23 mm/year. The high variation of corrosion rates is controlled by the aging pipes and smaller diameter. Also the phenolphthalein test on a cementitious core of cement mortar lined ductile cast iron pipe indicated the pipes over 15 years old had lost 50-100% of their lime active cross sectional area.

  16. Intergenerational Justice: How Reasonable Man Discounts Climate Damage

    Directory of Open Access Journals (Sweden)

    Marc D. Davidson

    2012-01-01

    Full Text Available Moral philosophers and economists have evaluated the intergenerational problem of climate change by applying the whole gamut of theories on distributive justice. In this article, however, it is argued that intergenerational justice cannot imply the application of moral ideal theories to future generations. The formal principle of equality simply requires us to treat like cases as like. If intergenerational justice is to have any meaning, it would require future generations to receive the same treatment under the law and the same treatment from the authorities, as far as cases are like. In the context of climate change, the reasonable man standard from tort law is of particular relevance. There is no justification to handle pollution across generational boundaries according to norms which differ from the (international laws for handling pollution across national borders. It is argued that this implies, for example, that a zero social rate of time preference should be used in cost-benefit analysis of climate policy: climate damage experienced by future generations should be discounted neither for their higher expected wealth, nor purely for their being remote.

  17. Validating Whole-Airway CFD Predictions of DPI Aerosol Deposition at Multiple Flow Rates.

    Science.gov (United States)

    Longest, P Worth; Tian, Geng; Khajeh-Hosseini-Dalasm, Navvab; Hindle, Michael

    2016-12-01

    The objective of this study was to compare aerosol deposition predictions of a new whole-airway CFD model with available in vivo data for a dry powder inhaler (DPI) considered across multiple inhalation waveforms, which affect both the particle size distribution (PSD) and particle deposition. The Novolizer DPI with a budesonide formulation was selected based on the availability of 2D gamma scintigraphy data in humans for three different well-defined inhalation waveforms. Initial in vitro cascade impaction experiments were conducted at multiple constant (square-wave) particle sizing flow rates to characterize PSDs. The whole-airway CFD modeling approach implemented the experimentally determined PSDs at the point of aerosol formation in the inhaler. Complete characteristic airway geometries for an adult were evaluated through the lobar bronchi, followed by stochastic individual pathway (SIP) approximations through the tracheobronchial region and new acinar moving wall models of the alveolar region. It was determined that the PSD used for each inhalation waveform should be based on a constant particle sizing flow rate equal to the average of the inhalation waveform's peak inspiratory flow rate (PIFR) and mean flow rate [i.e., AVG(PIFR, Mean)]. Using this technique, agreement with the in vivo data was acceptable with <15% relative differences averaged across the three regions considered for all inhalation waveforms. Defining a peripheral to central deposition ratio (P/C) based on alveolar and tracheobronchial compartments, respectively, large flow-rate-dependent differences were observed, which were not evident in the original 2D in vivo data. The agreement between the CFD predictions and in vivo data was dependent on accurate initial estimates of the PSD, emphasizing the need for a combination in vitro-in silico approach. Furthermore, use of the AVG(PIFR, Mean) value was identified as a potentially useful method for characterizing a DPI aerosol at a constant flow rate.

  18. Predicting rates of isotopic turnover across the animal kingdom: a synthesis of existing data.

    Science.gov (United States)

    Thomas, Stephen M; Crowther, Thomas W

    2015-05-01

    The stable isotopes of carbon ((12)C, (13)C) and nitrogen ((14)N, (15)N) represent powerful tools in food web ecology, providing a wide range of dietary information in animal consumers. However, identifying the temporal window over which a consumer's isotopic signature reflects its diet requires an understanding of elemental incorporation, a process that varies from days to years across species and tissue types. Though theory predicts body size and temperature are likely to control incorporation rates, this has not been tested empirically across a morphologically and phylogenetically diverse range of taxa. Readily available estimates of this relationship would, however, aid in the design of stable isotope food web investigations and improve the interpretation of isotopic data collected from natural systems. Using literature-derived turnover estimates from animal species ranging in size from 1 mg to 2000 kg, we develop a predictive tool for stable isotope ecologists, allowing for estimation of incorporation rates in the structural tissues of entirely novel taxa. In keeping with metabolic scaling theory, we show that isotopic turnover rates of carbon and nitrogen in whole organisms and muscle tissue scale allometrically with body mass raised approximately to the power -0.19, an effect modulated by body temperature. This relationship did not, however, apply to incorporation rates in splanchnic tissues, which were instead dependent on the thermoregulation tactic employed by an organism, being considerably faster in endotherms than ectotherms. We believe the predictive turnover equations we provide can improve the design of experiments and interpretation of results obtained in future stable isotopic food web studies. © 2014 The Authors. Journal of Animal Ecology © 2014 British Ecological Society.

  19. Weight suppression predicts total weight gain and rate of weight gain in outpatients with anorexia nervosa.

    Science.gov (United States)

    Carter, Frances A; Boden, Joseph M; Jordan, Jennifer; McIntosh, Virginia V W; Bulik, Cynthia M; Joyce, Peter R

    2015-11-01

    The present study sought to replicate the finding of Wildes and Marcus, Behav Res Ther, 50, 266-274, 2012 that higher levels of weight suppression at pretreatment predict greater total weight gain, faster rate of weight gain, and bulimic symptoms amongst patients admitted with anorexia nervosa. Participants were 56 women with anorexia nervosa diagnosed by using strict or lenient weight criteria, who were participating in a randomized controlled psychotherapy trial (McIntosh et al., Am J Psychiatry, 162, 741-747, 2005). Thirty-five women completed outpatient treatment and post-treatment assessment. Weight suppression was the discrepancy between highest lifetime weight at adult height and weight at pretreatment assessment. Outcome variables were total weight gain, rate of weight gain, and bulimic symptoms in the month prior to post-treatment assessment [assessed using the Eating Disorders Examination (Fairburn et al., Binge-Eating: Nature, Assessment and Treatment. New York: Guilford, 1993)]. Weight suppression was positively associated with total weight gain and rate of weight gain over treatment. Regression models showed that this association could not be explained by covariates (age at onset of anorexia nervosa and treatment modality). Weight suppression was not significantly associated with bulimic symptoms in the month prior to post-treatment assessment, regardless of whether bulimic symptoms were examined as continuous or dichotomous variables. The present study reinforces the previous finding that weight suppression predicts total weight gain and rate of weight gain amongst patients being treated for anorexia nervosa. Methodological issues may explain the failure of the present study to find that weight suppression predicts bulimic symptoms. Weight suppression at pretreatment for anorexia nervosa should be assessed routinely and may inform treatment planning. © 2015 Wiley Periodicals, Inc.

  20. Can we rely on predicted basal metabolic rate in chronic pancreatitis outpatients?

    Science.gov (United States)

    Olesen, Søren Schou; Holst, Mette; Køhler, Marianne; Drewes, Asbjørn Mohr; Rasmussen, Henrik Højgaard

    2015-04-01

    Malnutrition is a common complication to chronic pancreatitis (CP) and many patients need nutritional support. An accurate estimation of the basal metabolic rate (BMR) is essential when appropriate nutritional support is to be initiated, but in the clinical settings BMR is cumbersome to measure. We therefore investigated whether BMR can be reliable predicted from a standard formula (the Harris-Benedict equation) in CP outpatients. Twenty-eight patients with clinical stable CP and no current alcohol abuse were enrolled. Patients were stratified according to nutritional risk using the Nutrition Risk Screening 2002 system. Body composition was estimated using bioelectrical impedance. BMR was measured using indirect calorimetry and predicted using the Harris-Benedict equation based on anthropometric data. The average predicted BMR was 1371 ± 216 kcal/day compared to an average measured BMR of 1399 ± 231 kcal/day (P = 0.4). The corresponding limits of agreement were -347 to 290 kcal/day. Twenty-two patients (79%) had a measured BMR between 85 and 115% of the predicted BMR. When analysing patients stratified according to nutritional risk profiles, no differences between predicted and measured BMR were evident for any of the risk profile subgroups (all P > 0.2). The BMR was correlated to fat free mass determined by bioelectrical impedance (rho = 0.55; P = 0.003), while no effect modification was seen from nutritional risk stratification in a linear regression analysis (P = 0.4). The Harris-Benedict equation reliable predicts the measured BMR in four out of five clinical stable CP outpatients with no current alcohol abuse. Copyright © 2015 European Society for Clinical Nutrition and Metabolism. Published by Elsevier Ltd. All rights reserved.