Some variations on constrained minimum enclosing circle problem

Given a set P of n points and a straight line L, we study three important variations of minimum enclosing circle problem as follows:

1. Computing k identical circles of minimum radius with centers on L, whose union covers all the points in P.
2. Computing the minimum radius circle centered on L that can enclose at least k points of P.
3. If each point in P is associated with one of the k given colors, then compute a minimum radius circle with center on L such that at least one point of each color lies inside it.

We propose three algorithms for Problem (i). The first one runs in O(nklogn) time and O(n) space. The second one is efficient where k?n; it runs in O(nlogn+nk+k ²log³ n) time and O(nlogn) space. The third one is based on parametric search and it runs in O(nlogn+klog⁴ n) time. For Problem (ii), the time and space complexities of the proposed algorithm are O(nk) and O(n) respectively. For Problem (iii), our proposed algorithm runs in O(nlogn) time and O(n) space.     

Maternal Cocaine Use and Infant Behavior

This study examined the impact of maternal cocaine use and associated risk factors such as polysubstance use, maternal functioning, and caregiving on affect regulation during infancy. Participants were 45 mother‐infant dyads (19 cocaine exposed and 26 control infants) recruited at birth. Observations and maternal reports of infant behavior were obtained at 2 and 7 months of age, along with measures of pre‐ and postnatal substance use, maternal functioning, and caregiving stability. Maternal cocaine use accounted for significant variance in infant positive affect at 2 months. Other substance use and gestational age predicted infant distress to novelty and arousal during developmental assessments. At 7 months, the impact of prenatal cocaine exposure on infant affect regulation was mediated by postnatal alcohol use and caregiving stability. These findings, if replicated, suggest that 1 pathway to later problem behavior reported among substance‐exposed children may be through early regulatory problems and the quality of postnatal caregiving.     

INFERENCE IN DIRICHLET PROCESS MIXED GENERALIZED LINEAR MODELS BY USING MONTE CARLO EM

Generalized linear mixed models are widely used for describing overdispersed and correlated data. Such data arise frequently in studies involving clustered and hierarchical designs. A more flexible class of models has been developed here through the Dirichlet process mixture. An additional advantage of using such mixture models is that the observations can be grouped together on the basis of the overdispersion present in the data. This paper proposes a partial empirical Bayes method for estimating all the model parameters by adopting a version of the EM algorithm. An augmented model that helps to implement an efficient Gibbs sampling scheme, under the non‐conjugate Dirichlet process generalized linear model, generates observations from the conditional predictive distribution of unobserved random effects and provides an estimate of the average number of mixing components in the Dirichlet process mixture. A simulation study has been carried out to demonstrate the consistency of the proposed method. The approach is also applied to a study on outdoor bacteria concentration in the air and to data from 14 retrospective lung‐cancer studies.     

Community mentors as coaches: transforming gender norms through cricket among adolescent males in urban India

Addressing violence against women and girls (VAWG) through the medium of male team sport may be a promising strategy for addressing interpersonal violence and gender norms transformation in urban communities. Parivartan is a violence prevention programme in a large slum community in Mumbai, India, which works with men and boys to reduce violence and promote gender-equitable attitudes and beliefs via membership of a cricket team and mentoring from coaches. This article discusses findings from a recent evaluation of the programme.     

Antecedents of Innovativeness in Technology‐Based Services (TBS): Peering into the Black Box of Entrepreneurial Orientation

Innovativeness is the organization's capability for developing and introducing innovations. We argue that new combinations and recombinations of prior and new knowledge (by way of creating, assembling, and transforming knowledge) result in innovativeness in an organization. We further assert that a knowledge‐based focus on innovativeness is particularly important for firms that are technology‐based. The majority of studies focusing on innovativeness are in the entrepreneurship arena, and a large number of studies consider innovativeness as one of three dimensions of the entrepreneurial orientation (EO) construct, the other two dimensions being proactiveness and risk‐taking. However, recent research has suggested peering into the black box of EO by disaggregating the EO construct and examining the interrelationships among its three components. Hence, using the knowledge‐based view and drawing from multiple disciplines, our study conceptualizes innovativeness as a criterion variable and investigates the antecedent role of proactiveness and risk‐taking propensity on innovativeness in the context of technology‐based services (TBS). We hypothesize that both proactiveness and risk‐taking propensity exhibit a curvilinear relationship with innovativeness and introduce organizational structure formality as a moderator to further explicate these relationships. Our results show that proactiveness has a curvilinear (inverted U relationship) with innovativeness, and that this relationship is attenuated by organizational structure formality. Additional analysis indicates that in TBS firms, risk‐taking propensity has a positive linear relationship with innovativeness, and this relationship is accentuated by organizational structure formality. Finally, we discuss important conceptual and practical implications of our study and provide suggestions for future research.     

A measure of robust slope-rotatability for second-order response surface experimental designs

In response surface methodology, rotatability and slope-rotatability are natural and highly desirable properties for second-order regression models. In this paper a measure of robust slope-rotatability for second-order response surface designs with a general correlated error structure is developed and illustrated with different examples for autocorrelated error structure.     

Criticality in games with multiple levels of approval

In this article, criticality within a voting game is rigorously defined and examined. Criticality forms the basis of the traditional voting power measures frequently employed to analyse voting games; therefore understanding criticality is a pre-requisite to understanding any such analysis. The concept of criticality is extended to encompass games in which players are allowed to express multiple levels of approval. This seemingly innocuous extension raises some important questions, forcing us to re-evaluate exactly what it means to be critical. These issues have been largely side-stepped by the main body of research as they focus almost exclusively on ‘yes/no’ voting games, the so called single level approval voting games. The generalisation to multilevel approval voting games is much more than just a theoretical extension, as any single level approval game in which a player can abstain is in effect a multilevel approval voting game.     

Estimation of demographic measures for India, 1881-1961, based on census age distributions

Abstract India is one of the very few developing countries which have a relatively long history of population censuses. The first census was taken in 1872, the second in 1881 and since then there has been a census every ten years, the latest in 1971. Yet the registration of births and deaths in India, even at the present time, is too inadequate to be of much help in estimating fertility and mortality conditions in the country. From time to time Indian census actuaries have indirectly constructed life tables by comparing one census age distribution with the preceding one. Official life tables are available for all the decades from 1872-1881 to 1951-1961, except for 1911-1921 and 1931-1941. Kingsley Davis(1) filled in the gap by constructing life tables for the latter two decades. He also estimated the birth and death rates ofIndia for the decades from 1881-1891 to 1931-1941. Estimates of these rates for the following two decades, 1941-1951 and 1951-1961, were made by Indian census actuaries. The birth rates of Davis and the Indian actuaries were obtained basically by the reverse survival method from the age distribution and the computed life table of the population. Coale and Hoover(2), however, estimated the birth and death rates and the life table of the Indian population in 1951 by applying stable population theory. The most recent estimates of the birth rate and death rate for 1963-1964 are based on the results of the National Sample Survey. All these estimates are presented in summary form in Table 1.     

Dimensions of women’s autonomy and the influence on maternal health care utilization in a north indian city

The dimensions of women's autonomy and their relationship to maternal health care utilization were investigated in a probability sample of 300 women in Varanasi, India. We examined the determinants of women's autonomy in three areas: control over finances, decision-making power, and freedom of movement. After we control for age, education, household structure, and other factors, women with closer ties to natal kin were more likely to have greater autonomy in each of these three areas. Further analyses demonstrated that women with greater freedom of movement obtained higher levels of antenatal care and were more likely to use safe delivery care. The influence of women's autonomy on the use of health care appears to be as important as other known determinants such as education.     

Explaining Asia's “Missing Women”: A New Look at the Data

The fact that millions of females are “missing” in East Asia and South Asia has been attributed to cultural factors that support strong son preference in these countries. A widely disseminated paper by Emily Oster argues that a large part of this phenomenon can be attributed to excessively masculine sex ratios at birth resulting from maternal infection with hepatitis B. If her thesis is true, current policies to address this problem would need to be reframed to include biological factors in addition to cultural factors. The data show, however, that whether or not females “go missing” is determined by the existing sex composition of the family into which they are conceived. Girls with no older sisters have similar chances of survival as boys. However, girls conceived in families that already have a daughter experience steeply higher probabilities of being aborted or of dying in early childhood. This indicates that cultural factors still provide the overwhelming explanation for the “missing” females.