Oracle Inequalities for Convex Loss Functions with Nonlinear Targets

This article considers penalized empirical loss minimization of convex loss functions with unknown target functions. Using the elastic net penalty, of which the Least Absolute Shrinkage and Selection Operator (Lasso) is a special case, we establish a finite sample oracle inequality which bounds the loss of our estimator from above with high probability. If the unknown target is linear, this inequality also provides an upper bound of the estimation error of the estimated parameter vector. Next, we use the non-asymptotic results to show that the excess loss of our estimator is asymptotically of the same order as that of the oracle. If the target is linear, we give sufficient conditions for consistency of the estimated parameter vector. We briefly discuss how a thresholded version of our estimator can be used to perform consistent variable selection. We give two examples of loss functions covered by our framework.     

Temporal Disaggregation: Methods,Information Loss,and Diagnostics

This research provides a generalized framework to disaggregate lower-frequency time series and evaluate the disaggregation performance. The proposed framework combines two models in separate stages: a linear regression model to exploit related independent variables in the first stage and a state–space model to disaggregate the residual from the regression in the second stage. For the purpose of providing a set of practical criteria for assessing the disaggregation performance, we measure the information loss that occurs during temporal aggregation while examining what effects take place when aggregating data. To validate the proposed framework, we implement Monte Carlo simulations and provide two empirical studies. Supplementary materials for this article are available online.     

侵权法中的机会丧失理论

机会丧失理论即加害人的加害行为导致受害人获得利益或避免损害的机会丧失时,加害人应对此种机会的丧失承担损害赔偿责任的学说。它是对传统侵权法理论的修正和补充,并对损害、因果关系等侵权构成要件的传统学说造成了一定冲击。该理论在英美法系国家以及德国、法国等国的司法实践中多有运用,但关于其适用及其适用范围尚存诸多争议。我国机会丧失案件并不少见,但却没有采纳机会丧失理论。本文在介绍机会丧失理论的内涵及各国发展状况的基础上,着重探讨它在侵权法上适用的法律和政策方面的主要争议,并提出可供我国司法实践借鉴的建议。     

对国有资产中有形资产流失问题的探讨

国有资产中有形资产的流失存在动态流失与静态流失两种形式,动态流失因产权不清、管理不严或产权交易中规则不健全所致,具体又可分为经营性动态流失和人为性动态流失．静态流失与其是否进入市场交易有关．加强经济立法,完善和发展产权交易市场等可减少或避免国有有形资产的流失。     

Correlation in a Bayesian framework

The authors consider the correlation between two arbitrary functions of the data and a parameter when the parameter is regarded as a random variable with given prior distribution. They show how to compute such a correlation and use closed form expressions to assess the dependence between parameters and various classical or robust estimators thereof, as well as between p‐values and posterior probabilities of the null hypothesis in the one‐sided testing problem. Other applications involve the Dirichlet process and stationary Gaussian processes. Using this approach, the authors also derive a general nonparametric upper bound on Bayes risks.     

Job loss and family adjustments in work and schooling during the Mexican peso crisis

We use individual data from a panel of families during the depth of the peso crisis in Mexico to investigate whether the transition of the male household head from employment into unemployment affects the labor force participation of his spouse and children. We find that significant added-worker effects are in operation especially for adult females (wives), but no evidence that the labor force participation, the school attendance, and the likelihood of advancing to the next school grade of teenage males are influenced by the event of unemployment of the household head. The head's unemployment is significantly associated with a higher probability that teenage females do not attend school. However, lower attendance does not appear to impede their advancement to the next grade.

Pregnancy after loss during the COVID19 pandemic

BackgroundRapid changes to how maternity health care is delivered has occurred in many countries across the globe in response to the COVID-19 pandemic. Maternity care provisions have been challenged attempting to balance the needs and safety of pregnant women and their care providers. Women experiencing a pregnancy after loss (PAL) during these times face particularly difficult circumstances.AimIn this paper we highlight the situation in three high income countries (Australia, Ireland and USA) and point to the need to remember the unique and challenging circumstances of these PAL families. We suggest new practices may be deviating from established evidence-based guidelines and outline the potential ramifications of these changes.FindingsRecommendations for health care providers are suggested to bridge the gap between the necessary safety requirements due to the pandemic, the role of the health care provider, and the needs of families experiencing a pregnancy after loss.DiscussionChanges to practices i.e. limiting the number of antenatal appointments and access to a support person may have detrimental effects on both mother, baby, and their family. However, new guidelines in maternity care practices developed to account for the pandemic have not necessarily considered women experiencing pregnancy after loss.ConclusionBereaved mothers and their families experiencing a pregnancy after loss should continue to be supported during the COVID-19 pandemic to limit unintended consequences.     

Loss and grief: The experience of transition to residential aged care

There is growing recognition of the experience of non-death-related loss and grief. One unexplored area of non-death-related loss and grief is associated with older people’s transition from home to residential aged care (RAC). This paper reports findings from a qualitative study that explored the experiences of people living in RAC, carer-relatives of people living in RAC and RAC staff. Using theories of loss and grief, the paper identifies features of the transition to RAC that are associated with unresolved loss and maladaptation to changed circumstances, and the types of support that would mitigate these. Using a series of focus groups with both residents and carer-relatives, as well as staff, the study found that residents and their families need more support to negotiate the multiple, often necessarily hasty decisions and bureaucratic requirements associated with transitioning to RAC, while simultaneously experiencing loss and grief. The types of support that families would welcome from service providers include facilitating shared decision making, valuing family and community carer expertise and providing practical information and assistance to fulfil administrative obligations.     

Model selection consistency of U-statistics with convex loss and weighted lasso penalty

In the paper we consider minimisation of U-statistics with the weighted Lasso penalty and investigate their asymptotic properties in model selection and estimation. We prove that the use of appropriate weights in the penalty leads to the procedure that behaves like the oracle that knows the true model in advance, i.e. it is model selection consistent and estimates nonzero parameters with the standard rate. For the unweighted Lasso penalty, we obtain sufficient and necessary conditions for model selection consistency of estimators. The obtained results strongly based on the convexity of the loss function that is the main assumption of the paper. Our theorems can be applied to the ranking problem as well as generalised regression models. Thus, using U-statistics we can study more complex models (better describing real problems) than usually investigated linear or generalised linear models.