6,945 research outputs found
The demand for private schooling in England: the impact of price and quality
In this paper we use English school level data from 1993 to 2008 aggregated up to small neighbourhood areas to look at the determinants of the demand for private education in England from the ages of 7 until 15 (the last year of compulsory schooling). We focus on the relative importance of price and quality of schooling. However, there are likely to be unobservable factors that are correlated with private school prices and/or the quality of state schools that also impact on the demand for private schooling which could bias our estimates. Our long regional and local authority panel data allows us to employ a number of strategies to deal with this potential endogeneity. Because of the likely presence of incidental trends in our unobservables, we employ a double difference system GMM approach to remove both fixed effects and incidental trends. We find that the demand for private schooling is inversely related to private school fees as well as the quality of state schooling in the local area at the time families were making key schooling choice decisions at the ages of 7, 11 and 13. We estimate that a one standard deviation increase in the private school day fee when parents/students are making these key decisions reduces the proportion attending private schools by around 0.33 percentage points which equates to an elasticity of around -0.26. This estimate is only significant for choices at age 7 (but the point estimates are very similar at the ages of 11 and 13). At age 11 and age 13, an increase in the quality of local state secondary reduces the probability of attending private schools. At age 11, a one standard deviation increase in state school quality reduces participation in private schools by 0.31 percentage points which equates to an elasticity of -0.21. The effect at age 13 is slightly smaller, but still significant. Demand for private schooling at the ages of 8, 9, 10 and 12, 14 and 15 are almost entirely determined by private school demand in the previous year for the same cohort, and price and quality do not impact significantly on this decision other than through their initial influence on the key participation decisions at the ages of 7, 11 and 13.
Can twitter replace newswire for breaking news?
Twitter is often considered to be a useful source of real-time news, potentially replacing newswire for this purpose. But is this true? In this paper, we examine the extent to which news reporting in newswire and Twitter overlap and whether Twitter often reports news faster than traditional newswire providers. In particular, we analyse 77 days worth of tweet and newswire articles with respect to both manually identified major news events and larger volumes of automatically identified news events. Our results indicate that Twitter reports the same events as newswire providers, in addition to a long tail of minor events ignored by mainstream media. However, contrary to popular belief, neither stream leads the other when dealing with major news events, indicating that the value that Twitter can bring in a news setting comes predominantly from increased event coverage, not timeliness of reporting
Valuing Avoided Soil Erosion by Considering Private and Public Net Benefits
The population in New Zealand is expected to increase to over five million by the mid 2020’s from the current level of 4.3 million (Statistics New Zealand, 2009). An increasing demand for primary produce as a result may put pressure on marginal land to be farmed. Understanding the economic value of avoided erosion in New Zealand is therefore an important factor in policy making to optimise the soil related activities in the economy. Establishing a methodology for estimating the economic value of avoided soil erosion is the first step in assessing the problem. This study uses the future forest scenarios developed by Scion to identify potential afforestation areas and thereby compare the current erosion/sedimentation status under current land-use (non woody vegetation) with potential future afforestation. The study aims to quantify the incremental public and private net benefits from the change in scenario. The notion has come under different headings in the literature, such as on-site and off-site erosion effects or sediment and soil erosion effects, all of which recognize the importance of separation of effects to avoid double-counting. The separation into public and private benefits and costs in this case, while avoiding double-counting, will also help identify appropriate policy instruments to avoid soil erosion damage using the private and public net benefit framework (Pannell, 2008).Environmental Economics and Policy, Land Economics/Use,
Food choice by people with intellectual disabilities at day centres: A qualitative study
People with intellectual disabilities experience a range of health inequalities. It is important to investigate possible contributory factors that may lead to these inequalities. This qualitative study identified some difficulties for healthy eating in day centres. (1) Service users and their family carers were aware of healthy food choices but framed these as diets for weight loss rather than as everyday eating. (2) Paid carers and managers regarded the principle of service user autonomy and choice as paramount, which meant that they felt limited in their capacity to influence food choices, which they attributed to the home environment. (3) Carers used food as a treat, a reward and for social bonding with service users. (4) Service users’ food choices modelled other service users’ and carers’ choices at the time. It is suggested that healthy eating should be made more of a priority in day care, with a view to promoting exemplarily behaviour that might influence food choice at home
Evolution and nucleosynthesis of helium-rich asymptotic giant branch models
There is now strong evidence that some stars have been born with He mass
fractions as high as (e.g., in Centauri). However,
the advanced evolution, chemical yields, and final fates of He-rich stars are
largely unexplored. We investigate the consequences of He-enhancement on the
evolution and nucleosynthesis of intermediate-mass asymptotic giant branch
(AGB) models of 3, 4, 5, and 6 M with a metallicity of
([Fe/H] ). We compare models with He-enhanced compositions
() to those with primordial He (). We find that the
minimum initial mass for C burning and super-AGB stars with CO(Ne) or ONe cores
decreases from above our highest mass of 6 M to 4-5 M
with . We also model the production of trans-Fe elements via the slow
neutron-capture process (s-process). He-enhancement substantially reduces the
third dredge-up efficiency and the stellar yields of s-process elements (e.g.,
90% less Ba for 6 M, ). An exception occurs for 3 M,
where the near-doubling in the number of thermal pulses with leads to
50% higher yields of Ba-peak elements and Pb if the C neutron
source is included. However, the thinner intershell and increased temperatures
at the base of the convective envelope with probably inhibit the
C neutron source at this mass. Future chemical evolution models with our
yields might explain the evolution of s-process elements among He-rich stars in
Centauri.Comment: 21 pages, 16 figures, accepted for publication by MNRAS. Stellar
yields included as online data table
Marginal Abatement Costs of Carbon-Dioxide Emissions: A Meta-Analysis. ESRI WP248, June 2008
In this paper we carry out a meta-analysis of recent studies into the costs of greenhouse gas mitigation policies that aim at the long-term stabilization of these gases in the atmosphere. We find the cost estimates of the studies to be sensitive to the level of the stabilization target, the assumed emissions baseline, intertemporal optimisation, the choice of control variable (CO2 only versus multigas), assumptions on future technological options (backstop and carbon capture and storage), and, to a lesser degree, the scientific “forum” in which the study was developed
An industrial survey on the use of surface texture parameters
In 1999, CIRP conducted an industrial survey of the use of surface texture parameters [1]. In the seventeen years since, much has changed, with the most important advancement being the introduction of areal surface texture parameters as described in ISO 25178-2 [2]. There has also been the release of commercial software packages for the calculation of surface texture parameters and, therefore, it is expected that industry is starting to embrace areal surface texture characterisation. Industry is also increasingly using more optical instruments, which are often inherently areal in nature. These factors bring to light the need for a new parameter survey, to investigate whether industry really has been adopting areal surface texture parameters. This study used an online survey to obtain information about the current use of surface texture parameters in industry. The survey features both profile and areal surface texture parameters defined in specification standards ISO 4287 [3], ISO 25178-2 [2], ISO 12085 [4] and ISO 16565-2/3 [5, 6]. The survey was open to responses for eight months and obtained a total of 179 responses from a variety of industrial users of surface texture parameters spread across thirty-two countries. Responses from the survey offer information about the usage of individual surface texture parameters, highlighting any parameters that are unpopular and may require attention. The survey also enables participants to share their opinion on the current range of parameters in use, giving an insight into the perception of surface texture parameters in industry. The results from the survey highlight a strong adoption by industry of the areal surface texture parameters defined in ISO 25178-2. In comparison to the 1999 survey, there has also been an overall increase in the use of profile surface texture parameters, and an increase in the variety of parameters used, particularly for the ISO 4287 roughness parameters, suggesting a better understanding of the range of parameters available and their uses. Conversely, this increase in parameter variety could be due to the greater computational power available to users of surface texture parameters, allowing them to use more parameters with little cost. The results of the surface texture parameter survey will serve as an indication of the current state of the industry to those interested in the widespread acceptance and evolution of surface texture parameters. The analysis of the survey will identify common potential improvement areas in surface texture parameter selection and provide a starting point from which to better promote the current selection and better educate the users
Planetary ring studies
The following topics are covered: (1) characterization of the fine scale structure in Saturn's A and B rings; (2) ballistic transport modeling and evolution of fine ring structure; (3) faint features in the rings of Saturn; (4) the Encke moonlet; (5) dynamics in ringmoon systems; (6) a nonclassical radiative transfer model; and (7) particle properties from stellar occultation data
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The importance of including habitat-specific behaviour in models of butterfly movement
Dispersal is a key process affecting population persistence and major factors affecting dispersal rates are the amounts, connectedness and properties of habitats in landscapes. We present new data on the butterfly Maniola jurtina in flower-rich and flower-poor habitats that demonstrates how movement and behaviour differ between sexes and habitat types, and how this effects consequent dispersal rates. Females had higher flight speeds than males but their total time in flight was four times less. The effect of habitat type was strong for both sexes, flight speeds were ~2.5x and ~1.7x faster on resource-poor habitats for males and females respectively, and flights were approximately 50% longer. With few exceptions females oviposited in the mown grass habitat, likely because growing grass offers better food for emerging caterpillars, but they foraged in the resource-rich habitat. It seems that females faced a trade-off between ovipositing without foraging in the mown grass or foraging without ovipositing where flowers were abundant. We show that taking account of habitat-dependent differences in activity, here categorised as flight or non-flight, is crucial to obtaining good fits of an individual-based model to observed movement. An important implication of this finding is that incorporating habitat-specific activity budgets is likely necessary for predicting longer-term dispersal in heterogeneous habitats as habitat-specific behaviour substantially influences the mean (>30% difference) and kurtosis (1.4x difference) of dispersal kernels. The presented IBMs provide a simple method to explicitly incorporate known activity and movement rates when predicting dispersal in changing and heterogeneous landscapes
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