982 resultados para data adjustment


Relevância:

30.00% 30.00%

Publicador:

Resumo:

A growing literature supports the importance of understanding the link between religiosity and youths' adjustment and development, but in the absence of rigorous, longitudinal designs, questions remain about the direction of effect and the role of family factors. This paper investigates the bidirectional association between adolescents' relationship with God and their internalizing adjustment. Results from 2-wave, SEM cross-lag analyses of data from 667 mother/adolescent dyads in Belfast, Northern Ireland (50% male, M age = 15.75 years old) supports a risk model suggesting that greater internalizing problems predict a weaker relationship with God 1 year later. Significant moderation analyses suggest that a stronger relationship with God predicted fewer depression and anxiety symptoms for youth whose mothers used more religious coping.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Demand response is an energy resource that has gained increasing importance in the context of competitive electricity markets and of smart grids. New business models and methods designed to integrate demand response in electricity markets and of smart grids have been published, reporting the need of additional work in this field. In order to adequately remunerate the participation of the consumers in demand response programs, improved consumers’ performance evaluation methods are needed. The methodology proposed in the present paper determines the characterization of the baseline approach that better fits the consumer historic consumption, in order to determine the expected consumption in absent of participation in a demand response event and then determine the actual consumption reduction. The defined baseline can then be used to better determine the remuneration of the consumer. The paper includes a case study with real data to illustrate the application of the proposed methodology.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

BACKGROUND: American College of Cardiology/American Heart Association guidelines for the diagnosis and management of heart failure recommend investigating exacerbating conditions such as thyroid dysfunction, but without specifying the impact of different thyroid-stimulation hormone (TSH) levels. Limited prospective data exist on the association between subclinical thyroid dysfunction and heart failure events. METHODS AND RESULTS: We performed a pooled analysis of individual participant data using all available prospective cohorts with thyroid function tests and subsequent follow-up of heart failure events. Individual data on 25 390 participants with 216 248 person-years of follow-up were supplied from 6 prospective cohorts in the United States and Europe. Euthyroidism was defined as TSH of 0.45 to 4.49 mIU/L, subclinical hypothyroidism as TSH of 4.5 to 19.9 mIU/L, and subclinical hyperthyroidism as TSH <0.45 mIU/L, the last two with normal free thyroxine levels. Among 25 390 participants, 2068 (8.1%) had subclinical hypothyroidism and 648 (2.6%) had subclinical hyperthyroidism. In age- and sex-adjusted analyses, risks of heart failure events were increased with both higher and lower TSH levels (P for quadratic pattern <0.01); the hazard ratio was 1.01 (95% confidence interval, 0.81-1.26) for TSH of 4.5 to 6.9 mIU/L, 1.65 (95% confidence interval, 0.84-3.23) for TSH of 7.0 to 9.9 mIU/L, 1.86 (95% confidence interval, 1.27-2.72) for TSH of 10.0 to 19.9 mIU/L (P for trend <0.01) and 1.31 (95% confidence interval, 0.88-1.95) for TSH of 0.10 to 0.44 mIU/L and 1.94 (95% confidence interval, 1.01-3.72) for TSH <0.10 mIU/L (P for trend=0.047). Risks remained similar after adjustment for cardiovascular risk factors. CONCLUSION: Risks of heart failure events were increased with both higher and lower TSH levels, particularly for TSH ≥10 and <0.10 mIU/L.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

BACKGROUND: The escalating prevalence of obesity might prompt obese subjects to consider themselves as normal, as this condition is gradually becoming as frequent as normal weight. In this study, we aimed to assess the trends in the associations between obesity and self-rated health in two countries. METHODS: Data from the Portuguese (years 1995-6, 1998-6 and 2005-6) and Swiss (1992-3, 1997, 2002 and 2007) National Health Surveys were used, corresponding to more than 130,000 adults (64,793 for Portugal and 65,829 for Switzerland). Body mass index and self-rated health were derived from self-reported data. RESULTS: Obesity levels were higher in Portugal (17.5% in 2005-6 vs. 8.9% in 2007 in Switzerland, p < 0.001) and increased in both countries. The prevalence of participants rating their health as "bad" or "very bad" was higher in Portugal than in Switzerland (21.8% in 2005-6 vs 3.9% in 2007, p < 0.001). In both countries, obese participants rated more frequently their health as "bad" or "very bad" than participants with regular weight. In Switzerland, the prevalence of "bad" or "very bad" rates among obese participants, increased from 6.5% in 1992-3 to 9.8% in 2007, while in Portugal it decreased from 41.3% to 32.3%. After multivariate adjustment, the odds ratio (OR) of stating one self's health as "bad" or "very bad" among obese relative to normal weight participants, almost doubled in Switzerland: from 1.38 (95% confidence interval, CI: 1.01-1.87) in 1992-3 to 2.64 (95% CI: 2.14-3.26) in 2007, and similar findings were obtained after sample weighting. Conversely, no such trend was found in Portugal: 1.35 (95% CI: 1.23-1.48) in 1995-6 and 1.52 (95% CI: 1.37-1.70) in 2005-6. CONCLUSION: Obesity is increasing in Switzerland and Portugal. Obesity is increasingly associated with poorer self-health ratings in Switzerland but not in Portugal.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

This note develops general model-free adjustment procedures for the calculation of unbiased volatility loss functions based on practically feasible realized volatility benchmarks. The procedures, which exploit the recent asymptotic distributional results in Barndorff-Nielsen and Shephard (2002a), are both easy to implement and highly accurate in empirically realistic situations. On properly accounting for the measurement errors in the volatility forecast evaluations reported in Andersen, Bollerslev, Diebold and Labys (2003), the adjustments result in markedly higher estimates for the true degree of return-volatility predictability.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

In this paper we consider the estimation of population size from onesource capture–recapture data, that is, a list in which individuals can potentially be found repeatedly and where the question is how many individuals are missed by the list. As a typical example, we provide data from a drug user study in Bangkok from 2001 where the list consists of drug users who repeatedly contact treatment institutions. Drug users with 1, 2, 3, . . . contacts occur, but drug users with zero contacts are not present, requiring the size of this group to be estimated. Statistically, these data can be considered as stemming from a zero-truncated count distribution.We revisit an estimator for the population size suggested by Zelterman that is known to be robust under potential unobserved heterogeneity. We demonstrate that the Zelterman estimator can be viewed as a maximum likelihood estimator for a locally truncated Poisson likelihood which is equivalent to a binomial likelihood. This result allows the extension of the Zelterman estimator by means of logistic regression to include observed heterogeneity in the form of covariates. We also review an estimator proposed by Chao and explain why we are not able to obtain similar results for this estimator. The Zelterman estimator is applied in two case studies, the first a drug user study from Bangkok, the second an illegal immigrant study in the Netherlands. Our results suggest the new estimator should be used, in particular, if substantial unobserved heterogeneity is present.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Measured process data normally contain inaccuracies because the measurements are obtained using imperfect instruments. As well as random errors one can expect systematic bias caused by miscalibrated instruments or outliers caused by process peaks such as sudden power fluctuations. Data reconciliation is the adjustment of a set of process data based on a model of the process so that the derived estimates conform to natural laws. In this paper, techniques for the detection and identification of both systematic bias and outliers in dynamic process data are presented. A novel technique for the detection and identification of systematic bias is formulated and presented. The problem of detection, identification and elimination of outliers is also treated using a modified version of a previously available clustering technique. These techniques are also combined to provide a global dynamic data reconciliation (DDR) strategy. The algorithms presented are tested in isolation and in combination using dynamic simulations of two continuous stirred tank reactors (CSTR).

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Earlier estimates of the City of London office market are extended by considering a longer time series of data, covering two cycles, and by explicitly modeling of asymmetric space market responses to employment and supply shocks. A long run structural model linking real rental levels, office-based employment and the supply of office space is estimated and then rental adjustment processes are modeled using an error correction model framework. Rental adjustment is seen to be asymmetric, depending both on the direction of the supply and demand shocks and on the state of the space market at the time of the shock. Vacancy adjustment does not display asymmetries. There is also a supply adjustment equation. Two three-equation systems, one with symmetric rental adjustment and the other with asymmetric adjustment, are subjected to positive and negative shocks to employment. These illustrate differences in the two systems.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Models of the City of London office market are extended by considering a longer time series of data, covering two cycles, and by explicit modeling of asymmetric rental response to supply and demand model. A long run structural model linking demand for office space, real rental levels and office-based employment is estimated and then rental adjustment processes are modeled using an error correction model framework. Adjustment processes are seen to be asymmetric, dependent both on the direction of the supply and demand shock and on the state of the rental market at the time of the shock. A complete system of equations is estimated: unit shocks produce oscillations but there is a return to a steady equilibrium state in the long run.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Purpose: To review perceived emotional well-being in older people with visual impairment and perceived factors that inhibit/facilitate psychosocial adjustment to vision loss. Method: The databases of MEDLINE, EMBASE, PsycINFO and CINAHL were searched for studies published from January 1980 to December 2010, which recruited older people with irreversible vision loss, and used qualitative methods for both data collection and analysis. Results sections of the papers were synthesised using a thematic-style analysis to identify the emergent and dominant themes. Results: Seventeen qualitative papers were included in the review, and five main themes emerged from the synthesis: 1) the trauma of an ophthalmic diagnosis, 2) impact of vision loss on daily life, 3) negative impact of visual impairment on psychosocial well-being, 4) factors that inhibit social well-being, and 5) factors that facilitate psychological well-being. We found the response shift model useful for explaining our synthesis. Conclusions: Acquired visual impairment can have a significant impact on older people's well-being and make psychosocial adjustment to the condition a major challenge. Acceptance of the condition and a positive attitude facilitate successful psychosocial adjustment to vision loss as well as social support from family, friends and peers who have successfully adjusted to the condition. [Box: see text].

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The problem of spurious excitation of gravity waves in the context of four-dimensional data assimilation is investigated using a simple model of balanced dynamics. The model admits a chaotic vortical mode coupled to a comparatively fast gravity wave mode, and can be initialized such that the model evolves on a so-called slow manifold, where the fast motion is suppressed. Identical twin assimilation experiments are performed, comparing the extended and ensemble Kalman filters (EKF and EnKF, respectively). The EKF uses a tangent linear model (TLM) to estimate the evolution of forecast error statistics in time, whereas the EnKF uses the statistics of an ensemble of nonlinear model integrations. Specifically, the case is examined where the true state is balanced, but observation errors project onto all degrees of freedom, including the fast modes. It is shown that the EKF and EnKF will assimilate observations in a balanced way only if certain assumptions hold, and that, outside of ideal cases (i.e., with very frequent observations), dynamical balance can easily be lost in the assimilation. For the EKF, the repeated adjustment of the covariances by the assimilation of observations can easily unbalance the TLM, and destroy the assumptions on which balanced assimilation rests. It is shown that an important factor is the choice of initial forecast error covariance matrix. A balance-constrained EKF is described and compared to the standard EKF, and shown to offer significant improvement for observation frequencies where balance in the standard EKF is lost. The EnKF is advantageous in that balance in the error covariances relies only on a balanced forecast ensemble, and that the analysis step is an ensemble-mean operation. Numerical experiments show that the EnKF may be preferable to the EKF in terms of balance, though its validity is limited by ensemble size. It is also found that overobserving can lead to a more unbalanced forecast ensemble and thus to an unbalanced analysis.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Studies of international human resource management (IHRM) have pointed out that Japanese multinational companies (MNCs) tend to use more parent-country nationals (PCNs) than do western MNCs. The ethnocentric staffing policies imply that the management of expatriation has a greater influence on the success of Japanese MNCs. We use survey data from 149 Japanese repatriates to examine the relationship between IHRM practices – selection, preparation and corporate support – and expatriate adjustment and job performance, as well as identify differences by the location of assignment. We find that selection criteria, language ability and familiarity with local cultures are positively related to work adjustment, and that leadership and relational abilities are slightly associated with job performance though there were no significant relationships between considerations for family situations and adjustment or job performance. The results also reveal that HRM practices while abroad, in particular the interactive exchange of information between expatriates and the headquarters, have a significant influence. Pre-departure preparation programs are not related to the dependent variables. The data also suggests that living and working in China is a particular problem for Japanese expatriates.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Two alternate processes that may explain the relationship between child maltreatment, childhood family characteristics and adult adjustment (mediation and moderation) were tested using retrospective data from a community sample (N = 175). The levels of five different types of child maltreatment did not mediate the relationship between childhood family variables and adult adjustment. In contrast, family background played a mediating role in the relationship between maltreatment and adjustment. Evidence of moderation was found in the interactions between different maltreatment types in predicting adjustment. Partial support was found for the moderating influence of family factors on the relationship of maltreatment to adjustment.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The current study was designed to evaluate the impact of health, social relationships, work and coping on the adjustment and self-esteem of people with multiple sclerosis (MS). The participants were 251 people with MS (84 men, 167 women) and 184 people from the general population (56 men, 128 women). Data were obtained on the above variables using an anonymous questionnaire. In order to determine the impact of these relationships over time, the questionnaire was completed on two occasions, 18 months apart. The impact of health, social relationships, work and coping at time 1 on adjustment and self-esteem at time 2, was explored. The results indicated that there was a high level of stability in the levels of adjustment and self-esteem among both populations over time. People with MS experienced poorer adjustment and self-esteem, as well as poorer health, lower quality relationships, and lower work capacity than people from the general population. People with MS were also less likely to adopt problem focused or seeking social support coping, and more likely to adopt a detached style of coping. For both the MS and general populations, the most important predictors of adjustment and self-esteem at time 2 were time 1 levels of the same variables, with health, social relationships, work or coping strategies explaining little of the variance in time 2 levels of adjustment. The implications of this level of stability on the psychological adjustment of people with MS are discussed.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The relative contribution of geographical dislocation, attachment styles, coping behaviours, and autonomy, to successful student adjustment, was examined in relation to stress and well-being. A sample of 142 on campus first year university students, across four Victorian university campuses completed self-report questionnaires. Questionnaires included demographic, social network, intrapsychic (attachment and autonomy), and coping variables. Multiple regression analysis revealed that being female, not having made a friend to confide in personal matters, lower achieved autonomy, and use of emotion-focused coping predicted higher levels of student stress. A second multiple regression analysis revealed that living away from home, and preferring others to approach oneself to initiate conversation or friendships predicted lower well-being, whilst increased frequency of phone and email contact, and greater secure parent and peer attachment, predicted greater well-being. Pearson's correlations indicated that securely attached students used more problem focused coping and social support, whereas insecurely attached students used more emotion focused coping. Qualitative data indicated student concerns about being away from family and friends, finance, course direction and structure, social opportunities on campus, and generally adjusting to the university culture. It was concluded that first year on-campus students would benefit from program initiatives targeting enhancement of on-campus social opportunities, development of autonomy, problem focused coping behaviour, interpersonal and social assertiveness.