A study on the mean past lifetime of the components of (n − k + 1)-out-of-n system at the system level

In the present paper, we consider a (n − k + 1)-out-of-n system with identical components where it is assumed that the lifetimes of the components are independent and have a common distribution function F. We assume that the system fails at time t or sometime before t, t > 0. Under these conditions, we are interested in the study of the mean time elapsed since the failure of the components. We call this as the mean past lifetime (MPL) of the components at the system level. Several properties of the MPL are studied. It is proved that the relation between the proposed MPL and the underlying distribution is one-to-one. We have shown that when the components of the system have decreasing reversed hazard then the MPL of the system is increasing with respect to time. Some examples are also provided.     

Investigating the importance of self‐acceptance and self‐efficacy on weight management in a developing country

The growing rates of obesity in both developed and developing countries are alarming. Most studies on obesity mainly focus on individuals in developed countries with ready access to food. Limited studies explore obesity in developing countries with limited access to healthier foods. In addition, studies show self‐acceptance and self‐efficacy are essential to healthier well‐being. The purpose of this study is (a) to explore the impact of self‐acceptance on individuals' self‐efficacy to weight management and (b) to investigate the impact of self‐efficacy on individuals' attitude and intention in regard to weight managements. Using data from Indonesia (N = 499), the respondents are divided based on their body mass index. The results show that self‐acceptance significantly influenced individuals' self‐efficacy, especially for individuals who are obese. Furthermore, self‐efficacy did not influence individual attitude toward weight management. Finally, attitude toward weight management only influenced people who are obese and not individuals who are overweight. The results of this study will have significant implications to government, social marketers, and not‐for‐profit organizations in fighting the epidemic in developing countries.     

Truth and Robustness in Cross‐country Growth Regressions*

We re‐examine studies of cross‐country growth regressions by Levine and Renelt (American Economic Review, Vol. 82, 1992, pp. 942–963) and Sala‐i‐Martin (American Economic Review, Vol. 87, 1997a, pp. 178–183; Economics Department, Columbia, University, 1997b). In a realistic Monte Carlo experiment, their variants of Edward Leamer's extreme‐bounds analysis are compared with a cross‐sectional version of the general‐to‐specific search methodology associated with the LSE approach to econometrics. Levine and Renelt's method has low size and low power, while Sala‐i‐Martin's method has high size and high power. The general‐to‐specific methodology is shown to have a near nominal size and high power. Sala‐i‐Martin's method and the general‐to‐specific method are then applied to the actual data from Sala‐i‐Martin's original study.     

Estimation of quantities determined as implicit functions of unknown parameters

Consider a family of distribution functions ${\{F(x, \theta),\,\theta \in \Theta\}}Consider a family of distribution functions {F(x, q), q ? Q}{\{F(x, \theta),\,\theta \in \Theta\}} . Suppose that there exists an estimator of the unknown parameter vector θ based on given data set. Then it is readily to obtain an estimator of any quantity given as an explicit function g(θ). Particularly, it is the case when the maximum likelihood estimator of θ is available. However, often some quantities of interest can not be expressed as an explicit function, rather it is determined as an implicit function of θ. The present article studies this problem. Sufficient conditions are given for deriving estimators of these quantities. The results are then applied to estimate change point of failure rate function, and change point of mean residual life function.     

An Analysis of Causal Flow Between Social Development and Economic Growth:

This is an attempt to examine whether there is any causal relation between social development and economic growth. Social development in this context is measured by a social development index, which is a weighted composite index formed with eight social indicators of life representing various spheres of social life. Economic growth is indicated by Per Capita Real Gross Domestic Product (PCRGDP), The causality test offered by Granger has been performed for the entire sample as well as for three income groups: high, middle and low. The study also tests causality between PCRGDP and the eight social indicators of life.     

Tailoring but not targeting: a critical analysis of “the Meth Project” aimed at Hispanic youth

• This paper examines the Meth Project, a social marketing campaign that enlists violence and fear to persuade Anglo and Hispanic youth in the USA to avoid methamphetamines. Violent and graphic media spots, although perhaps initially effective for facilitating message acceptance, may be counterproductive for long‐term campaign objectives. We draw on Witte's Extended Parallel Process Model to conceptualize how fear, risk, and behavior drive health‐related behaviors. Merely translating the Anglo spots into Spanish is an insufficient strategy to reach Hispanic youth because it targets rather than tailors its message. Significant findings of content analyses show that public service announcements in Spanish, unexpectedly, underscore recovering users' concern for violating norms with schools, employers, and law enforcement (secondary groups), whereas the Anglo spots show users more upset for disappointing family, friends, and loved ones (primary groups). Culturally appropriate Latino spots should tailor their messages to the values of familism, collectivism, simpatía, personalismo, and respeto, which have implications for reaching Hispanic audiences in other social marketing contexts.

Copyright © 2016 John Wiley & Sons, Ltd.     

Limited arbitrage is necessary and sufficient for the existence of an equilibrium

In Chichilnisky (Working Paper No. 586, 1991), Chichilnisky (Working Paper No. 650, 1992) and Chichilnisky (Economic Theory, 1995, 5, 79–108), I introduced the concept of a global cone and used it to define a condition on endowments and preferences, ‘limited arbitrage’, which I showed to be necessary and sufficient for the existence of a competitive equilibrium. In response to a comment (Monteiro et al., Journal of Mathematical Economics, 1997, 26, 000-000), I show here that the authors misunderstood my results by focussing on brief announcements which cover other areas, social choice (Chichilnisky, American Economic Review, 1994, 427–434 and algebraic topology (Chichilnisky, Bulletin of the American Mathematical Society, 1993, 29, 189–207), rather than on the publication which contains may proofs on equilibrium. The comment's example is irrelevant to my results in Chichilnisky (Economic Theory, 1995, 5, 79–108) because it starts from different conditions. Limited arbitrae is always necessary and sufficient for the existence of a competitive equilibrium, with or without short sales, with the global cones as I defined them, and exactly as proved in Chichilnisky (Economic Theory, 1995, 5, 79–108).     

Multivariate likelihood ratio orderings between spacings of heterogeneous exponential random variables

Let X ₁, X ₂, ..., X _n be independent exponential random variables such that X _i has failure rate λ for i = 1, ..., p and X _j has failure rate λ^* for j = p + 1, ..., n, where p ≥ 1 and q = n − p ≥ 1. Denote by D _i:n (p,q) = X _i:n −X _i-1:n the ith spacing of the order statistics X _1:n ≤ X _2:n ≤ ... ≤ X _n:n , i = 1, ..., n, where X _0:n ≡ 0. The purpose of this paper is to investigate multivariate likelihood ratio orderings between spacings D _i:n (p,q), generalizing univariate comparison results in Wen et al.(J Multivariate Anal 98:743–756, 2007). We also point out that such multivariate likelihood ratio orderings do not hold for order statistics instead of spacings. Supported by National Natural Science Foundation of China, the Program for New Century Excellent Talents in University (No.: NCET-04-0569), and by the Knowledge Innovation Program of the Chinese Academy of Sciences (No.: KJCX3-SYW-S02).     

Some properties of the minimum and the maximum of random variables with joint logconcave distributions

It is shown that if (X ₁, X ₂, . . . , X _n ) is a random vector with a logconcave (logconvex) joint reliability function, then X _P = min _i∈P X _i has increasing (decreasing) hazard rate. Analogously, it is shown that if (X ₁, X ₂, . . . , X _n ) has a logconcave (logconvex) joint distribution function, then X ^P  = max _i∈P X _i has decreasing (increasing) reversed hazard rate. If the random vector is absolutely continuous with a logconcave density function, then it has a logconcave reliability and distribution functions and hence we obtain a result given by Hu and Li (Metrika 65:325–330, 2007). It is also shown that if (X ₁, X ₂, . . . , X _n ) has an exchangeable logconcave density function then both X _P and X ^P have increasing likelihood ratio.     

Application of Quality of Life Indicators to Socioeconomic Problems:

Abstract . Liu has presented and applied to several categories of areas a method of estimating comparative values for measuring the quality of life. This method is analyzed and extended through an application permitting evaluation of social and economic policies for country towns in Australia. Issues in Liu's method, particularly relating to the procedure for standardizing measurements and a much-needed validation test, are examined and, it is hoped, resolved. The nature of Liu's results is compared with that of the Australian results and they are found to be similar, particularly in that the quality of life values were useful in explaining migration, and were even better in explaining certain components of migration. The study extended the method to analysis of policy choices.     

Estimating a restricted normal mean

Let X ₁, X ₂, ..., X _n be a random sample from a normal distribution with unknown mean μ and known variance σ ². In many practical situations, μ is known a priori to be restricted to a bounded interval, say [−m, m] for some m > 0. The sample mean , then, becomes an inadmissible estimator for μ. It is also not minimax with respect to the squared error loss function. Minimax and other estimators for this problem have been studied by Casella and Strawderman (Ann Stat 9:870–878, 1981), Bickel (Ann Stat 9:1301–1309, 1981) and Gatsonis et al. (Stat Prob Lett 6:21–30, 1987) etc. In this paper, we obtain some new estimators for μ. The case when the variance σ ² is unknown is also studied and various estimators for μ are proposed. Risk performance of all estimators is numerically compared for both the cases when σ ² may be known and unknown.     

Predictability and Reflexivity

Abstract . Reflexive predictions are self-defeating or self-fulfilling. However, it was shown that in most cases of self defeating public predictions of social events conceptually at least one correct prediction exists. Unfortunately the term “reflexive prediction” is applied in the literature to quite distinct phenomena. A. Grünbaum, moreover, argued that reflexive prediction occurs also in the natural sciences using as example the fire-control system which “obeys only natural laws.” The purpose of this paper is two fold: first, it clarifies the terminological confusion. Second, it argues that every man-made tool (fire-control systems are tools) obeys natural laws and so does the person. The question of a person's higher functions, such as expectation and decision is only acknowledged. The conclusions are (1) that there is a fundamental difference between reaction to public (predictive) utterances and reaction to discriminatory behavior based on private ptediciion. (2) The reflexivity of public prediction is a phenomenon characteristic of the social sciences. at least as long as these disciplines are set apart from the natural sciences.     

Moment consistency of estimators in partially linear models under NA samples

Consider the heteroscedastic regression model Y ^(j)(x _in , t _in ) = t _in β + g(x _in ) + σ _in e ^(j)(x _in ), 1 ≤ j ≤ m, 1 ≤ i ≤ n, where s_in²=f(u_in){\sigma_{in}^{2}=f(u_{in})}, (x _in , t _in , u _in ) are fixed design points, β is an unknown parameter, g(·) and f(·) are unknown functions, and the errors {e ^(j)(x _in )} are mean zero NA random variables. The moment consistency for least-squares estimators and weighted least-squares estimators of β is studied. In addition, the moment consistency for estimators of g(·) and f(·) is investigated.     

Structural VARs and noninvertible macroeconomic models

We resume the line of research pioneered by C. A. Sims and Zha (Macroeconomic Dynamics, 2006, 10, 231–272) and make two novel contributions. First, we provide a formal treatment of partial fundamentalness—that is, the idea that a structural vector autoregression (VAR) can recover, either exactly or with good approximation, a single shock or a subset of shocks, even when the underlying model is nonfundamental. In particular, we extend the measure of partial fundamentalness proposed by Sims and Zha to the finite‐order case and study the implications of partial fundamentalness for impulse‐response and variance‐decomposition analysis. Second, we present an application where we validate a theory of news shocks and find it to be in line with the empirical evidence.     

When is a Compositional Effect not a Compositional Effect?

The question of compositional effects (that is, the effect of collective properties of a pupil body on the individual members), or Aggregated Group-Level Effects (AGLEs) as the author prefers to call them, has been the subject of considerable controversy. Some authors, e.g. Rutter et al. [Fifteen thousand hours: Secondary Schools and Their Effects on Children. London: Open Books.], Willms [Oxford Review of Education 11(1): 33–41; (1986). American Sociological Review, 51, 224–241.], Bondi [British Educational Research Journal, 17(3), 203-218.], have claimed to find such effects, while on the other hand Mortimore et al. [School Matters: the Junior Years. Wells: Open Books.] and Thomas and Mortimore [Oxford Review of Education 16(2): 137–158.] did not. Others, for example Hauser [1970], have implied that many apparent AGLEs may be spurious, while Gray et al. [Review of Research in Education, 8, 158–193.] have suggested that at least in certain circumstances such apparent effects may arise as a result of inadequate allowance for pre-existing differences. A possible statistical mechanism for this is outlined in the work of Burstein [In R. Dreeben, & J. A. Thomas (Eds.), The Analysis of Educational Productivity. Volume 1: Issues in Microanalysis, Cambridge, MASS: Ballinger, pp. 119–190] on the effect of aggregating the data when a variable is omitted from the model used. This paper suggests another way in which spurious AGLEs can arise. It shows mathematically that even if there are no omitted variables, measurement error in an explanatory variable could give rise to apparent, but spurious, AGLEs, when analysed using a multilevel modelling procedure. Using simulation methods, it investigates what the practical effects of this are likely to be, and shows that statistically significant spurious effects occur systematically under fairly standard conditions.     

Mission-first social enterprises: A case study of how three nonprofit organizations avoided mission drift when forming and operating social enterprises

The purpose of this study was to examine how leaders of nonprofit social enterprises manage the tension between social mission and financial goals to avoid mission drift. The study employed a case study/cross-case analysis design and used the qualitative research methods of interviewing, document review, and participant observation. We found tremendous variation in the strategies created for the organizations included in the study (n = 3). We labeled strategies as (a) structured ignorance, (b) problem reframing, and (c) defensible trade-offs. Further research is needed to identify a comprehensive typology of strategies; however, there are immediate practical and social implications of this study. Specifically, the strategies identified here can be considered by nonprofit practitioners struggling with the mission/money tension. Additionally, these strategies challenge commonly held beliefs about the relationship among nonprofits, social service, and revenue generating activities.     

Lose weight for a raise only if overweight: Marginal integration for semi‐linear panel models

Some studies have shown that body mass index (BMI), weight (kg)/height (m)², has a negative (or no) effect on wage. But BMI representing obesity is a tightly specified function of weight and height, and there is a room for weight given height (i.e. obesity given height) to better explain wage when the tight specification gets relaxed. In this paper, we address the question of weight effect on wage given height, employing two‐wave panel data for white females and adopting a semi‐linear model consisting of a nonparametric function of weight and height and a linear function of the other regressors. We find that there is no weight effect on wage up to the average weight, beyond which a large negative effect kicks in. Linear BMI models give the incorrect impression of the presence of a ‘wage gain’ by becoming slimmer than the average and of a ‘wage loss’ that is less than what it actually is when going above the average. Copyright © 2010 John Wiley & Sons, Ltd.     

Value-relevant Sociology: The Analysis of Subjects of Social Consequence, Including Implications for Human Well-being

Abstract . The need for sociology to become socially relevant is now being articulated by professional sociologists. While the doctrine that the discipline should be value-free allows sociologists to serve and promote the social values of others, a vital sociological endeavor requires more. Classic sociology was value-relevant. To be socially relevant, it is essential that the discipline become consciously value-relevant, not value-free. For sociology to distinguish important from unimportant social problems and actions requires judgments of relative social value. What social theory, what social policies, and why? Significant sociology analyzes the consequences of social structure, forces and change. This cannot be done in a value-free context, especially so for sociologists who are interested in matters of social policy.     

Asymptotic normality of M-estimators in a semiparametric model with longitudinal data

Suppose that the longitudinal observations (Y _ij , X _ij , t _ij ) for i = 1, . . . ,n; j = 1, . . . ,m _i are modeled by the semiparamtric model where β ₀ is a k × 1 vector of unknown parameters, g(·) is an unknown estimated function and e _ij are unobserved disturbances. This article consider M-type regressions which include mean, median and quantile regressions. The M-estimator of the slope parameter β ₀ is obtained through piecewise local polynomial approximation of the nonparametric component. The local M-estimator of g(·) is also obtained by replacing β ₀ in model with its M-estimator and using local linear approximation. The asymptotic distribution of the estimator of β ₀ is derived. The asymptotic distributions of the local M-estimators of g(·) at both interior and boundary points are also established. Various applications of our main results are given. The research is supported in part by National Natural Science Foundation of China (Grant No. 10671089).     

Sacred alliance or pact with the devil? How and why social enterprises collaborate with mainstream businesses in the fair trade sector*

Abstract

This paper uses institutional theory to highlight different patterns of cross-sector collaboration from the perspective of social enterprises. Specifically, it explores how and why social enterprises interact with mainstream businesses and to what extent their collaboration patterns reflect a vision of how their social mission should be implemented and institutionalized. The empirical analysis is derived from a qualitative study of ‘fair trade’ – a hybrid model created by social enterprises and using market mechanisms to support small-scale producers in developing countries and to advocate for changes in international trading practices. The findings highlight three strategies used by fair trade social enterprises to manage their interactions with mainstream businesses: sector solidarity, selective engagement, and active appropriation. This paper suggests that each strategy is motivated by a different vision of how best to articulate the social mission of fair trade via specific types of collaborations. It also notes how each vision has a distinct pattern of institutionalization at the field level. This paper adds to the emergent literatures on social enterprise and social entrepreneurship, fair trade, cross-sector collaboration and hybrid organizing.