Net worth and the economic diversity of the elderly

Using data from the 1984 panel of the Survey of Income and Program Participation (SIPP), this article examines characteristics of the older population disaggregated by net-worth quintiles. The authors argue that income is not a sufficient measure of economic status for current policy discussions on issues such as changing Medicare co-payments, increasing the taxation of social security benefits, or means-testing under Medicaid. Net worth is a better measure of economic status, particularly for the elderly, because it represents the net value of assets accumulated over the life course. Their results indicate that there is considerable diversity in the economic status of the older population, which is masked by aggregate statistics (such as means and medians) typically used to summarize the economic status of population groups. Stereotypical views of the elderly based on such aggregates result in misdirected policy formulation. In the future, policymakers will need to formulate policies and programs using information on the distributions of income and assets among the older populations rather than relying on statistical aggregates.     

Successful Word Recognition by 10‐Month‐Olds Given Continuous Speech Both at Initial Exposure and Test

Most words that infants hear occur within fluent speech. To compile a vocabulary, infants therefore need to segment words from speech contexts. This study is the first to investigate whether infants (here: 10‐month‐olds) can recognize words when both initial exposure and test presentation are in continuous speech. Electrophysiological evidence attests that this indeed occurs: An increased extended negativity (word recognition effect) appears for familiarized target words relative to control words. This response proved constant at the individual level: Only infants who showed this negativity at test had shown such a response, within six repetitions after first occurrence, during familiarization.     

Prediction and Prevention of Child Abuse and Neglect

A high-risk population was successfully identified by the use of perinatal screening procedures. These children encountered significantly different parenting practices than the low-risk "control" group. There were also significant differences between "High-Risk" and "Low-Risk" families on issues concerning social adjustment and mother/infant attachment. Five children in a "High-Risk Nonintervene" group required hospitalization for serious injuries thought to be secondary to abnormal parenting practices. There were no such hospitalizations in either a High Risk Intervene group or a Low Risk group. Labordelivery observations, and postpartum interviews and observations provided the most accurate predictive information; prenatal interviews and questionnaires did not add significantly. Perinatal assessment and simple intervention with families at high risk for abnormal parenting practices significantly improves the infants' chances for escaping serious hospitalized physical injury.     

Estimation for u-shaped beta distributions: minimum hellinger distance and related methods

We compare minimum Hellinger distance and minimum Heiiinger disparity estimates for U-shaped beta distributions. Given suitable density estimates, both methods are known to be asymptotically efficient when the data come from the assumed model family, and robust to small perturbations from the model family. Most implementations use kernel density estimates, which may not be appropriate for U-shaped distributions. We compare fixed binwidth histograms, percentile mesh histograms, and averaged shifted histograms. Minimum disparity estimates are less sensitive to the choice of density estimate than are minimum distance estimates, and the percentile mesh histogram gives the best results for both minimum distance and minimum disparity estimates. Minimum distance estimates are biased and a bias-corrected method is proposed. Minimum disparity estimates and bias-corrected minimum distance estimates are comparable to maximum likelihood estimates when the model holds, and give better results than either method of moments or maximum likelihood when the data are discretized or contaminated, Although our re¬sults are for the beta density, the implementations are easily modified for other U-shaped distributions such as the Dirkhlet or normal generated distribution.     

Estimation of a Conditional Copula and Association Measures

Abstarct. This paper is concerned with studying the dependence structure between two random variables Y ₁ and Y ₂ conditionally upon a covariate X. The dependence structure is modelled via a copula function, which depends on the given value of the covariate in a general way. Gijbels et al. (Comput. Statist. Data Anal., 55, 2011, 1919) suggested two non‐parametric estimators of the ‘conditional’ copula and investigated their numerical performances. In this paper we establish the asymptotic properties of the proposed estimators as well as conditional association measures derived from them. Practical recommendations for their use are then discussed.     

Comparing Ourselves to Others: International Knowledge and Attitudes

The authors focus on the collaboration between a university methods professor and two classroom teachers in teaching social studies methods as a way of bridging the gap between university preparation for teaching social studies and putting that preparation into practice in elementary classrooms. The teachers offer recommendations from their own teaching experiences for how preservice teachers can find time for powerful social studies teaching despite pressures to meet the requirements of No Child Left Behind in literacy and mathematics. They integrate social studies with literacy and math, use "teachable moments" and transitions between subjects, and incorporate social studies research with computer and media skills. In addition, they employ class meetings to practice the democratic processes of collectively setting and revising class rules, accepting responsibility for those rules, and working together to solve classroom problems. Informal feedback from the preservice teachers reflects their appreciation of advice from classroom teachers with current experience in addressing the challenge of making time for powerful social studies teaching.     

The perception of occupational stress and its relation to research and teaching among academic staff

Abstract

A sample of full-time teaching staff from a former polytechnic participated in a study to examine the relationships between their perception of occupational stress and their involvement in research. Information was obtained from 60% of staff approached. The mean scores on the Occupational Stress Indicator (OSI) for job satisfaction and stress-related measures of mental health and physical health did not differ significantly from data obtained in previous studies on university academic personnel. Scores on these variables were not significantly related to research activity. The degree of satisfaction and degree of stress emanating from participation in research, in teaching and in administration were separately assessed in structured interviews.     

The study of commission rate problem in real-time bidding

This paper studies the commission rate in real-time bidding based on the generalized first-price auction mechanism. Firstly, the equilibrium bidding strategies are provided when there are fixed commission rate and the linear commission rate, which proves that if the there is no reserve price, the expected payment of DSP is not related to the rate of commission. The commission rate affects the equilibrium bidding strategies only. Secondly, this paper shows that if there are the reserve price and the commission, the payment of DSP is increasing on the commission rate. That is, if there is reserve price, the DSP cannot control the increasing of the expected payment by adjusting the equilibrium bidding strategy, when the commission rate increases. Finally, provided that the reserve price and commission rate are exogenous respectively, this paper draws to the conclusion that the conditions of optimal commission rate and the optimal reserve price must be satisfied.