Stakeholder Green Pressure and New Product Performance in Emerging Countries: A Cross-country Study

Despite the burgeoning literature on stakeholder green pressure, research is scarce on how it influences eco-product innovation and new product performance. This article examines stakeholder green pressures as antecedents of eco-product innovation and new product performance in firms operating in resource-constrained countries. Using data gathered from surveys in Vietnam (N = 183) and Ghana (N = 217), we find that the positive effects of stakeholder green pressures on new product performance are serially mediated by environmental sustainability orientation and eco-product innovation. Our findings contribute to ongoing efforts to clarify the mechanisms channelling stakeholder pressures into new product performance in resource-constrained environments.     

Staying safe and visible via message sharing in online social networks

As an imperative channel for fast information propagation, online social networks (OSNs) also have their defects. One of them is the information leakage, i.e., information could be spread via OSNs to the users whom we are not willing to share with. Thus the problem of constructing a circle of trust to share information with as many friends as possible without further spreading it to unwanted targets has become a challenging research topic but still remained open. Our work is the first attempt to study the Maximum Circle of Trust problem seeking to share the information with the maximum expected number of poster’s friends such that the information spread to the unwanted targets is brought to its knees. First, we consider a special and more practical case with the two-hop information propagation and a single unwanted target. In this case, we show that this problem is NP-hard, which denies the existence of an exact polynomial-time algorithm. We thus propose a Fully Polynomial-Time Approximation Scheme (FPTAS), which can not only adjust any allowable performance error bound but also run in polynomial time with both the input size and allowed error. FPTAS is the best approximation solution one can ever wish for an NP-hard problem. We next consider the number of unwanted targets is bounded and prove that there does not exist an FPTAS in this case. Instead, we design a Polynomial-Time Approximation Scheme (PTAS) in which the allowable error can also be controlled. When the number of unwanted targets are not bounded, we provide a randomized algorithm, along with the analytical theoretical bound and inapproximaibility result. Finally, we consider a general case with many hops information propagation and further show its #P-hardness and propose an effective Iterative Circle of Trust Detection (ICTD) algorithm based on a novel greedy function. An extensive experiment on various real-world OSNs has validated the effectiveness of our proposed approximation and ICTD algorithms. Such an extensive experiment also highlights several important observations on information leakage which help to sharpen the security of OSNs in the future.     

A Hybrid Geometric Phase II/III Clinical Trial Design based on Treatment Failure Time and Toxicity

The problem of comparing several experimental treatments to a standard arises frequently in medical research. Various multi-stage randomized phase II/III designs have been proposed that select one or more promising experimental treatments and compare them to the standard while controlling overall Type I and Type II error rates. This paper addresses phase II/III settings where the joint goals are to increase the average time to treatment failure and control the probability of toxicity while accounting for patient heterogeneity. We are motivated by the desire to construct a feasible design for a trial of four chemotherapy combinations for treating a family of rare pediatric brain tumors. We present a hybrid two-stage design based on two-dimensional treatment effect parameters. A targeted parameter set is constructed from elicited parameter pairs considered to be equally desirable. Bayesian regression models for failure time and the probability of toxicity as functions of treatment and prognostic covariates are used to define two-dimensional covariate-adjusted treatment effect parameter sets. Decisions at each stage of the trial are based on the ratio of posterior probabilities of the alternative and null covariate-adjusted parameter sets. Design parameters are chosen to minimize expected sample size subject to frequentist error constraints. The design is illustrated by application to the brain tumor trial.     

A primal-dual approximation algorithm for the Asymmetric Prize-Collecting TSP

We present a primal-dual ?log(n)?-approximation algorithm for the version of the asymmetric prize collecting traveling salesman problem, where the objective is to find a directed tour that visits a subset of vertices such that the length of the tour plus the sum of penalties associated with vertices not in the tour is as small as possible. The previous algorithm for the problem (V.H. Nguyen and T.T Nguyen in Int. J. Math. Oper. Res. 4(3):294–301, 2012) which is not combinatorial, is based on the Held-Karp relaxation and heuristic methods such as the Frieze et al.’s heuristic (Frieze et al. in Networks 12:23–39, 1982) or the recent Asadpour et al.’s heuristic for the ATSP (Asadpour et al. in 21st ACM-SIAM symposium on discrete algorithms, 2010). Depending on which of the two heuristics is used, it gives respectively 1+?log(n)? and $3+ 8\frac{\log(n)}{\log(\log(n))}$ as an approximation ratio. Our algorithm achieves an approximation ratio of ?log(n)? which is weaker than $3+ 8\frac{\log(n)}{\log(\log(n))}$ but represents the first combinatorial approximation algorithm for the Asymmetric Prize-Collecting TSP.     

On the asymptotic behaviour of the recursive Nadaraya–Watson estimator associated with the recursive sliced inverse regression method

We investigate the asymptotic behaviour of the recursive Nadaraya–Watson estimator for the estimation of the regression function in a semiparametric regression model. On the one hand, we make use of the recursive version of the sliced inverse regression method for the estimation of the unknown parameter of the model. On the other hand, we implement a recursive Nadaraya–Watson procedure for the estimation of the regression function which takes into account the previous estimation of the parameter of the semiparametric regression model. We establish the almost sure convergence as well as the asymptotic normality for our Nadaraya–Watson estimate. We also illustrate our semiparametric estimation procedure on simulated data.     

Impact of internal migration on the economic well-being of local workers and school dropouts among children in Vietnam

This study examines the impact of migration on local workers and high school dropouts of local students. A conventional approach without addressing the endogeneity issue may lead to biased results. Our endogeneity-corrected estimates show a positive impact of migration on the monthly wages of local workers. A higher share of migrants increases the probability of local workers with employment contracts, social insurance, and holiday pay. Heterogeneity analysis shows that local workers, no matter their educational level, work experience, or occupation sectors, benefit from the inflow of migrants. Finally, migration inflow lowers the probability of high school dropouts among local students. Our findings resulting from rigorous statistical approaches suggest that internal migration produces positive impacts on the economic well-being of local residents, refuting the argument about the adverse effects associated with internal migration.     

Different Effects of Acculturative Stress and Family Life Stress on Depressive Symptoms among Married Vietnamese Immigrant Women in South Korea

Married Vietnamese immigrant women often face multiple stressors related to sociocultural adaptation and new family lives in South Korea. The purpose of this paper is to identify the different influences of acculturative and family life stress on depressive symptoms among Vietnamese immigrant wives. Data were collected through a questionnaire survey of 301 married Vietnamese immigrant women residing in South Korea. The study utilized linear regression analysis to test the relationships between the variables. The findings show that both acculturative and family life stress are positively related to depressive symptoms. Family life stress influences depressive symptoms to a greater extent than acculturative stress. The study emphasizes the significance of family‐related stress on mental health among married Vietnamese immigrant women in Korea and provides some implications for research, clinical practice, and policy.     

Making Meanings,Meaning Identity: Hmong Adolescent Perceptions and Use of Language and Style as Identity Symbols

Using qualitative interview data gathered from 28 Hmong adolescents, we examined the meaning ascribed to language and style and how language and style behaviors are used to distinguish identity. We found that the participants used language and style to define their own ethnic group membership and cultural identities. Moreover they inferred meaning from these identity behaviors to discern which peer groups are desirable (those who wear American style clothing and are bilingual) and which are of low social status (“fobby” style clothing and monolingual). The cultural identity symbols used by participants reveal heterogeneity among Hmong adolescent peer groups and evolving definitions of what it means to be Hmong in America.