A modification of a continuous time model for first conception

The interval between marriage and the first conception leading to a live birth plays an important role in the determination of fertility components. Several probability models (Potter and Parker, 1964; Singh, 1961, 1964, 1967) based on varying sets of assumptions relating to this interval have been propounded in the recent past. All of them are based on the assumption that the females under study are susceptible to conception at the time of marriage. However, in certain situations, where some of the females already pregnant at the time of marriage report to have conceived within a short interval following marriage, this condition is not satisfied and these models become unsuitable. A probability distribution which is an inflated form of the continuous model proposed by Singh, for the time of the first conception leading to a live birth, is presented in this paper. It describes reasonably well the data on first conception times in the context of premarital conceptions. Simple expressions for the maximum likelihood estimators of the parameters involved in the model are obtained and a method for finding the asymptotic covariance matrix of the estimators is outlined. The model is applied to four sets of data.     

Population planning in Asia in the 1970s

Summary To what extent is family planning integrated with broader population planning in the countries of East Asia and South Asia? To what degree do these countries combine population planning with economic and social planning in their development plans? An attempt to answer these questions suggests that, despite variability from country to country in development goals and policy implementation, family planning has been largely separated from economic planning, and birth control programmes have often been substituted for intermediate and long-range population planning. Demographic factors have been treated as exogenous variables rather than as integral parts of social-economic-demographic plans. Such comprehensive planning is difficult for both technical and political reasons, but in any case is unlikely to be achieved so long as family planning and population planning continue to be confused.     

Confronting the Material Convoy in Later Life

We adapt a metaphor from life course studies to designate the whole of one's possessions, across time, as a convoy of material support. This dynamic collection of things supports daily life and the self, but it can also present difficulty in later life. To alleviate the purported burdens of the material convoy, a discourse has arisen that urges elders and their family members to reduce the volume of possessions. An analysis of 11 such possession management texts shows authors addressing two distinct audiences about elders' need to downsize: family members and elders themselves. Authors who speak to family members do so with an urgent, unsentimental tone that echoes mainstream clutter-control advice about disorderly, overfull households. In texts for elders, the standard critique about consumption and unruly lives is gentler, more sensitive to the meaning of things, and underplays the emotions of divestment. There is stress on the responsibility to spare the next generation and control one's legacy. These latter texts seem to respect that downsizing in later life symbolizes a narrowing of the life world.     

Cultural mechanisms and the persistence of neighborhood violence

Sociologists have given considerable attention to identifying the neighborhood-level social-interactional mechanisms that influence outcomes such as crime, educational attainment, and health. Yet, cultural mechanisms are often overlooked in quantitative studies of neighborhood effects. This paper adds a cultural dimension to neighborhood effects research by exploring the consequences of legal cynicism. Legal cynicism refers to a cultural frame in which people perceive the law as illegitimate, unresponsive, and ill equipped to ensure public safety. The authors find that legal cynicism explains why homicide persisted in certain Chicago neighborhoods during the 1990s despite declines in poverty and declines in violence city-wide.     

Personality, drug preference, drug use, and drug availability

This study examined the relationship between drug preference, drug use, drug availability, and personality among individuals (n = 100) in treatment for substance abuse in an effort to replicate the results of an earlier study (Feldman, Kumar, Angelini, Pekala, & Porter, 2007) designed to test prediction derived from Eysenck's (1957, 1967) theories. Drug preference was measured by the method of paired-comparison and personality was measured with the Zuckerman-Kuhlman Personality Questionnaire-50 CC. Contrary to expectations, high compared with low scorers on Sociability and Impulsive-Sensation Seeking preferred depressants. Surprisingly, low compared with high scorers on neuroticism did not differ in preference for alcohol. As in the previous study, drug preference, use, and availability were highly correlated, although ease of availability was slightly more predictive of drug use than drug preference. Clinical and theoretical implications are discussed.     

Stimulating Early Adoption of New Products through Channel Disintegration

Conventional wisdom holds that adding layers to a distribution channel is detrimental to the interests of consumers and the channel that serves them. In contrast, our study indicates that a disintegrated channel structure can be desirable in some instances. When consumers have valuation uncertainty prior to consuming a product, having an independent retailer may boost both channel profits and consumer surplus relative to direct selling by an integrated firm. The quandary in selling such products is that after early adopters make their purchase decisions, the seller may alter prices in such a way that makes early adopters' decisions appear suboptimal in hindsight. Since the seller cannot credibly commit to future prices, customers are reluctant to adopt early, choosing instead to delay their purchase decisions. This delay is certainly detrimental to the interest of the distribution channel, but the rejection of the early adoption discount can equally reduce consumer surplus. This problem can be mitigated by introducing an independent retailer. The familiar double marginalization “problem” from channel disintegration can credibly assure customers of unfavorable future prices for late adoption. This assurance attracts more customers to seek early adoption, leading to lower overall retail prices, increased supply, and higher consumer and producer surpluses.     

Distributed Development and Product Line Decisions

Distributed product development is becoming increasingly prevalent in a number of industries. We study how the global distribution of product development impacts the profit‐maximizing product line that a firm offers. Specifically, we formulate a model to understand the linkage between cost arbitrage as a driver of distributed development and consequent market implications such as customer perceived quality loss to remotely developed products. Analysis of the model reveals that a firm should expand the product line for a development‐intensive good only at intermediate values of cost advantage and quality loss. We modify the base model to include development capacity constraints as a driver of distributed development and find that the results are robust to this change. Our analysis affirms the need for product managers to incorporate the implications of distributed development in making their product line design decision.     

Should I stay or should I go? Congestion pricing and equilibrium selection in a transportation network

Theory and Decision - When imposing traffic congestion pricing around downtown commercial centers, there is a concern that commercial activities will have to consider relocating due to reduced...     

Reliability and Validity of the European Portuguese Version of the Social Touch Questionnaire

Social touch is essential for physical and emotional well-being. However, different meanings can be attributed to physical contact during social interactions and may generate bonding or avoidant behaviors. This personal and unique experience is not usually taken into account in health and social care services. The aim of this study is to produce a valid and reliable European Portuguese version of the Social Touch Questionnaire (STQ, Wilhelm et al. in Biol Psychol 58:181–202, 2001. doi: 10.1016/S0301-0511(01)00113-2). The STQ is a self-report questionnaire for adolescents and adults measuring behaviors and attitudes towards social touch. The original version was translated into European Portuguese using a forward-back translation process and its feasibility was examined. To evaluate the psychometric properties, a total of 242 Portuguese university students participated in the study (21.3 ± 3.8 years). The STQ was considered feasible, showed adequate internal consistency (Cronbach’s α = .734), and the test–retest correlation with the STQ items demonstrated a high concordance between the tests over a two-week interval (ICC = .990; n = 50). Validity tests were performed, comparing the total score of the STQ with that of the anxiety and avoidance subscales of the Social Interaction and Performance Anxiety and Avoidance Scale (SIPAAS). A very significant conceptual convergence was confirmed between the STQ and with the SIPAAS-Anxiety (r = .64; p < .0001) and with the SIPAAS-Avoidance (r = .59; p < .0001). The exploratory factor analysis, with Promax rotation, revealed 3 factors: dislike of physical touch, liking of familiar physical touch and liking of public physical touch (Cronbach’s alphas ranged from .68 to .75). Psychometric properties confirmed the adaptation of the STQ to the Portuguese culture. It is a reliable and valid self-report questionnaire and it appears to be a useful tool to assess behaviors and attitudes towards social touch.