966 resultados para MOMENTS
Resumo:
Objective: Interventions to reduce health inequalities for young children and their mothers are important: involving peers is recommended, but evidence of value for this approach is limited. The authors aimed to examine the effect of an innovative tailored peer-mentoring programme, based on perceived needs, for first-time mothers in socio-economically deprived communities. Design: Randomised controlled trial; parallel qualitative study with purposive samples using semistructured interviews. Setting: Socio-economically disadvantaged areas, Belfast. Participants: Primigravidae, aged 16-30 years, without significant co-morbidity. Intervention: Peer-mentoring by a lay-worker fortnightly during pregnancy and monthly for the following year, tailored to participants' wishes (home visits/telephone contacts), additional to usual care. Main outcome measures: Infant psychomotor and mental development (Bayley Scales of Infant Development (BSID-II)) at 1 year, assessed by an observer blinded to group allocation. Mothers' health at 1 year postnatal (SF-36). Results: Of 534 women invited, 343(64%) participated; 85%, with their children, completed outcome assessments (140 of 172 intervention; 152 of 171 controls). Intervention and control groups did not differ in BSID-II psychomotor (mean difference 1.64, 95% CI -0.94 to 4.21) or mental (-0.81, -2.78 to 1.16) scores, nor SF-36 physical functioning (-5.4, -11.6 to 0.7) or mental health (-1.8, -6.1 to 2.6). Women valued advice given in context of personal experience of child-rearing. Mentors gained health-related knowledge, personal skills and new employment opportunities. Conclusions: Despite possible longer-term social advantage, this peer-mentoring programme showed no benefit for infant development or maternal health at 1 year. Further rigorous evaluation of important outcomes of complex interventions promoting health for children in socially disadvantaged communities is warranted. Trial registration no: ISRCTN 55055030.
Resumo:
Value-at-risk (VaR) forecasting generally relies on a parametric density function of portfolio returns that ignores higher moments or assumes them constant. In this paper, we propose a simple approach to forecasting of a portfolio VaR. We employ the Gram-Charlier expansion (GCE) augmenting the standard normal distribution with the first four moments, which are allowed to vary over time. In an extensive empirical study, we compare the GCE approach to other models of VaR forecasting and conclude that it provides accurate and robust estimates of the realized VaR. In spite of its simplicity, on our dataset GCE outperforms other estimates that are generated by both constant and time-varying higher-moments models.
Resumo:
Drawing on material from the BBC Written Archive Centre, this article examines the earliest sf dramas broadcast by the BBC Television Service: two adaptations of Karel Capek's "R.U.R." ("Rossum's Universal Robots") from 1938 and 1948. These productions are used as sites of formal experimentation with the possibilities of the new medium, representing one aspect of contemporary debates about the purpose of television and the style it would assume.
Resumo:
It is a legitimate assertion that the common ground of work of worth in architecture, whether theoretical or built comes from a firmly held position on the part of the author. In addition to delivery key competencies architectural education should act to support the formation of such a position in the student, or to make students aware of the possibility of holding such a position.
It is with this in mind perhaps that intensive unit-based diploma and masters structures are increasingly becoming the standard structure for for schools of architecture across the UK. The strengths of such a structure are most evident when the school, either by virtue of financial strength or geographic location is able to attract a diverse range of contrasting positions to bear in the formation of these units. In effect the offering to the student is a short, intensive immersion into a clear line of thought based on the position of those running the unit. Research is channeled by those running the unit to the work of the students. A single cohort of students therefore is able to observe and understand a wide range of ways of thinking about the subject whether or not they are participants in a unit or not. It is axiomatic that where this structure is applied in the absence of these resources the result can be less helpful, individual units are differentiated not to reflect the interests of those running the unit but for the sake of difference as its own end.
In structuring the M.Arch programme in Queens University Belfast the reality of our somewhat peripheral location was placed at the forefront of our considerations. A single 4 semester studio is offered. The first three semesters are carefully structured to offer a range of directed and self directed projects to the students. By interrogation of these projects, and work undertaken at undergraduate level the aim is to assist the students to identify a personal position on architecture, which is then developed in the thesis in semester four. Research and design outputs are emergent from the interest of the student body, cultivated by staff who have the time over the four semesters to get to know all aspects of a students interests.
This paper will lay out this structure and some of the projects run within it. Now having delivered two graduating years the successes and challenges of the system will be laid out by reference to several case studies of individual student experiences of the structure.
Resumo:
In this study, we propose a new semi-nonparametric (SNP) density model for describing the density of portfolio returns. This distribution, which we refer to as the multivariate moments expansion (MME), admits any non-Gaussian (multivariate) distribution as its basis because it is specified directly in terms of the basis density’s moments. To obtain the expansion of the Gaussian density, the MME is a reformulation of the multivariate Gram-Charlier (MGC), but the MME is much simpler and tractable than the MGC when positive transformations are used to produce well-defined densities. As an empirical application, we extend the dynamic conditional equicorrelation (DECO) model to an SNP framework using the MME. The resulting model is parameterized in a feasible manner to admit two-stage consistent estimation and it represents the DECO as well as the salient non-Gaussian features of portfolio return distributions. The in- and out-of-sample performance of a MME-DECO model of a portfolio of 10 assets demonstrate that it can be a useful tool for risk management purposes.
Resumo:
This paper examines the role of higher-order moments in portfolio choice within an expected-utility framework. We consider two-, three-, four- and five-parameter density functions for portfolio returns and derive exact conditions under which investors would all be optimally plungers rather than diversifiers. Through comparative statics we show the importance of higher-order risk preference properties, such as riskiness, prudence and temperance, in determining plunging behaviour. Empirical estimates for the S&P500 provide evidence for the optimality of diversification.
Resumo:
We reconsider a formula for arbitrary moments of expected discounted dividend payments in a spectrally negative L,vy risk model that was obtained in Renaud and Zhou (2007, [4]) and in Kyprianou and Palmowski (2007, [3]) and extend the result to stationary Markov processes that are skip-free upwards.