47,088 research outputs found

    Can we estimate the impact of the choices package in pathways to work?

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    The Pathways to Work programme is an important policy innovation in Britain. It provides greater support, obligations and incentives for claimants of incapacity benefits with the goal of encouraging employment. The programme has various components, including a 'Choices' package. 'Choices' is the collective name for a variety of voluntary schemes intended to improve labour market readiness and opportunities. Previous quantitative research has focused on the overall impact of Pathways to Work while this study was designed to look at the impact of the Choices component

    Financial work incentives in Britain: comparisons over time and between family types

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    This paper reviews various techniques for quantifying financial incentives to work, shows how financial work incentives have changed across the population since 1979, and estimates how much of these changes are due to changes in the tax and benefit system

    Normal mere exposure effect with impaired recognition in Alzheimer’s disease.

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    We investigated the mere exposure effect and the explicit memory in Alzheimer’s disease (AD) patients and elderly control subjects, using unfamiliar faces. During the exposure phase, the subjects estimated the age of briefly flashed faces. The mere exposure effect was examined by presenting pairs of faces (old and new) and asking participants to select the face they liked. The participants were then presented with a forced-choice explicit recognition task. Controls subjects exhibited above-chance preference and recognition scores for old faces. The AD patients also showed the mere exposure effect but no explicit recognition. These results suggest that the processes involved in the mere exposure effect are preserved in AD patients despite their impaired explicit recognition. The results are discussed in terms of Seamon et al.’s proposal (1995) that processes involved in the mere exposure effect are equivalent to those subserving perceptual priming. These processes would depend on extrastriate areas which are relatively preserved in AD patients

    Aid versus trade revisited

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    This paper examines the (non) equivalance between aid flows and trade preferences as alternative forms of donor assistance in the presence of learning-by-doing externalities in recipient country export production. Using a two-period model based on vanWijnbergen (1985), in which the productivity externality consistitues the only (inter-temporal) distortion, we show that switching donor support on the margin from aid to trade preferences can increase recipient country welfare. To evaluate the size of this potential welfare gain to small African economies we simulate donor policy reforms using a dynamic CGE model where the productivity externality may also interact with private capital accumulation. We show that for reasonable values of key behavioural parameters, the potential growth and welfare gains from a (donor) revenue neutral re-orientation of assistance to developing countries could be substantial. The paper concludes by considering why these potential dynamic gains appear to be unexpoited by both donors and recipients.Foreign Aid, Trade Preferences, Africa.

    Developing analytical distributions for temperature indices for the purposes of pricing temperature-based weather derivatives

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    Temperature-based weather derivatives are written on an index which is normally defined to be a nonlinear function of average daily temperatures. Recent empirical work has demonstrated the usefulness of simple time-series models of temperature for estimating the payoffs to these instruments. This paper develops analytical distributions of temperature indices on which temperature derivatives are written. If deviations of daily temperature from its expected value is modelled as an Ornstein-Uhlenbeck process with time-varying variance, then the distributions of the temperature index on which the derivative is written is the sum of truncated, correlated Gaussian deviates. The key result of this paper is to provide an analytical approximation to the distribution of this sum, thus allowing the accurate computation of payoffs without the need for any simulation. A data set comprising average daily temperature spanning over a hundred years for four Australian cities is used to demonstrate the efficacy of this approach for estimating the payoffs to temperature derivatives. It is demonstrated that expected payoffs computed directly from historical records is a particulary poor approach to the problem when there are trends in underlying average daily temperature. It is shown that the proposed analytical approach is superior to historical pricing.Weather Derivatives, Temperature Models, Cooling Degree Days, Maximum Likelihood Estimation, Distribution for Correlated Variables

    Early quantitative evidence on the impact of the pathways to work pilots

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    Since October 2003 the Department for Work and Pensions (DWP) has been piloting reforms in England, Scotland and Wales which provide greater support alongside greater obligations to encourage many new claimants of incapacity benefits to move into paid work. The Pathways to Work package of reforms includes: a series of usually mandatory workfocused interviews; programmes designed to boost claimants' prospects of being able to work; and increased financial incentives for individuals to enter paid employment. As part of a quantitative assessment of the impact of the programme, a telephone survey of those making an initial enquiry to Jobcentre Plus about claiming incapacity benefits was conducted in both pilot and comparison areas before and after the pilots were implemented. This report focuses on the differences in some early quantitative outcomes between Pathways and non-Pathways areas. Two empirical techniques are used to investigate the early impact of the pilots on employment, earnings, receipt of incapacity benefits, and a potential indicator of the extent to which individuals' health affects their everyday activities. The analysis was undertaken by researchers at the Institute for Fiscal Studies and the telephone interviews were undertaken by the National Centre for Social Research. All these findings are preliminary: more comprehensive analysis will be conducted in later stages of the evaluation. This report analyses outcomes at a time shortly after the pilots started. Further analysis of outcomes will assess Pathways to Work using survey and administrative data from a later cohort and will examine outcomes over a longer period of time

    Estimating the Payoffs of Temperature-based Weather Derivatives

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    Temperature-based weather derivatives are written on an index which is normally defined to be a nonlinear function of average daily temperatures. Recent empirical work has demonstrated the usefulness of simple time-series models of temperature for estimating the payoffs to these instruments. This paper argues that a more direct and parsimonious approach is to model the time-series behaviour of the index itself, provided a sufficiently rich supply of historical data is available. A data set comprising average daily temperature spanning over a hundred years for four Australian cities is assembled. The data is then used to compare the actual payoffs of temperature-based European call options with the expected payoffs computed from historical temperature records and two time-series approaches. It is concluded that expected payoffs computed directly from historical records perform poorly by comparison with the expected payoffs generated by means of competing time-series models. It is also found that modeling the relevant temperature index directly is superior to modeling average daily temperatures.Temperature, Weather Derivatives, Cooling Degree Days, Time-series Models.

    Off-Mass-Shell π\piN Scattering and pp→ppπ0pp \to pp \pi^0

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    We adapt the off-shell π\piN amplitude of the Tucson-Melbourne three-body force to the half-off-shell amplitude of the pion rescattering contribution to pp→ppπ0pp \to pp \pi^0 near threshold. This {\em pion} rescattering contribution, together with the impulse term, provides a good description of the data when the half-off-shell amplitude is linked to the phenomenological invariant amplitudes obtained from meson factory π\piN scattering data.Comment: 3 pages, contributed to STORRI99, Bloomington, Indiana, September 199

    Quantifying the Biases of Spectroscopically Selected Gravitational Lenses

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    Spectroscopic selection has been the most productive technique for the selection of galaxy-scale strong gravitational lens systems with known redshifts. Statistically significant samples of strong lenses provide a powerful method for measuring the mass-density parameters of the lensing population, but results can only be generalized to the parent population if the lensing selection biases are sufficiently understood. We perform controlled Monte Carlo simulations of spectroscopic lens surveys in order to quantify the bias of lenses relative to parent galaxies in velocity dispersion, mass axis ratio, and mass density profile. For parameters typical of the SLACS and BELLS surveys, we find: (1) no significant mass axis ratio detection bias of lenses relative to parent galaxies; (2) a very small detection bias toward shallow mass density profiles, which is likely negligible compared to other sources of uncertainty in this parameter; (3) a detection bias towards smaller Einstein radius for systems drawn from parent populations with group- and cluster-scale lensing masses; and (4) a lens-modeling bias towards larger velocity dispersions for systems drawn from parent samples with sub-arcsecond mean Einstein radii. This last finding indicates that the incorporation of velocity-dispersion upper limits of \textit{non-lenses} is an important ingredient for unbiased analyses of spectroscopically selected lens samples. In general we find that the completeness of spectroscopic lens surveys in the plane of Einstein radius and mass-density profile power-law index is quite uniform, up to a sharp drop in the region of large Einstein radius and steep mass density profile, and hence that such surveys are ideally suited to the study of massive field galaxies.Comment: Accepted for publication in Astrophys. J., June 7, 2012. In press. 9 pages, 5 figures, 1 tabl
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