Solution Procedures for the Lot-Streaming Problem

Lot streaming is the process of splitting a job into sublots so its operations can be overlapped and its progress accelerated. We present a computationally efficient procedure for solving the m-machine, two-sublot problem, and we discuss the bottleneck insights that emerge from the analysis. We also examine heuristic approaches for more than two sublots and discuss computational results for these procedures.     

Resource Flexibility Issues in Multistage Manufacturing

We test the situational impact of two types of resource flexibility, machine flexibility and labor flexibility, in a material requirements planning (MRP)-driven production system. Machine flexibility has not been treated in prior multistage research, only labor flexibility. Machine flexibility is closely related to a plant's positioning strategy. A process-focused plant opts for considerable machine flexibility by choosing general-purpose equipment. Resource flexibility, if effective, can be an attractive alternative to two other types of buffers, inflated inventories and costly capacity cushions. Our simulation results, using factor settings established earlier by a panel of managers, show that resource flexibility is indeed an effective buffer against uncertainties such as end-item demand variability, capacity bottlenecks, equipment failures, and yield losses. Machine flexibility is especially helpful in environments characterized by high uncertainties, tight capacities, and large lot sizes. Worker flexibility has a similar, but less dramatic, impact. Benefits are most striking with customer service, rather than with inventory or labor productivity. Finally, we show that simultaneous introduction of both machine and labor flexibility yields only marginal improvements over either kind of flexibility alone.     

The belonging model of trust

Although we know that high‐quality employee–organization relationships are beneficial, these relationships are complex and not fully understood, especially among employees of nonprofit organizations. In particular, we know little about how these employees perceive trust, which may overlook an important contributor to effective management. We begin to address this issue by testing a new theoretical model that conceptualizes perceived insider status, psychological ownership, and organizational identification as foundations for the perception of justice and subsequent trust. Our results indicate that psychological ownership and perceived insider status relate to trust through procedural and interpersonal justice. These results contrast those typically found in for‐profit contexts in that organizational identification did not predict justice and that distributive and informational justice did not predict trust.     

Mother–Adolescent and Father–Adolescent Relationships After Divorce: Relations with Emerging Adults’ Romantic Attachment

This longitudinal study examined relations between mother–child relationship quality and father support in adolescence (ages 15–19) and emerging adults’ (ages 24–28) romantic anxiety and avoidance in a sample that experienced parental divorce in childhood (n = 72). A significant interactive effect of mother–adolescent relationship quality and father support on romantic anxiety occurred. High levels of father support protected emerging adults from the negative effects of a low quality mother–adolescent relationship. These results highlight the importance of examining effects of one parental relationship in the context of the other and the role that nonresidential fathers play in influencing their offspring’s romantic attachment.     

Parental Alienation: A Measurement Tool

The Rowlands Parental Alienation Scale (RPAS) was administered to 592 parents along with measures of convergent and discriminant validity. The scale was designed to capture the eight domains of parental alienating behavior posited in the literature. Factor analysis extracted only six factors, one of which was not included in the original eight: (a) campaign of denigration towards the alienated parent, (b) the independent thinker phenomenon, (c) reflexive support, (d) presence of borrowed scenarios, (e) spread of animosity to extended family, and (f) lack of positive affect towards the alienated parent. Parents who reported either that a court evaluation or court findings had confirmed the presence of parental alienation scored significantly higher on all six RPAS factors as well as on the overall RPAS score.     

Is Sexual Abuse a Unique Predictor of Sexual Risk Behaviors,Pregnancy, and Motherhood in Adolescence?

This study tested sexual abuse as a unique predictor of subsequent adolescent sexual behaviors, pregnancy, and motherhood when in company with other types of maltreatment (physical abuse, neglect) and alternative behavioral, family, and contextual risk factors in a prospective, longitudinal study of maltreated (n = 275) and comparison (n = 239) nulliparous females aged 14–19 years old assessed annually through 19 years old. Hierarchical regression was used to disentangle risk factors that account for the associations of maltreatment type on risky sexual behaviors at 19 years old, adolescent pregnancy, and adolescent motherhood. Findings indicate that sexual and physical abuse remain significant predictors of risky sexual behaviors, and that sexual abuse remains a significant predictor of adolescent motherhood when alternative explanatory variables are controlled.     

“To get the word out”: LGBTQ+ Young adults’ motivations for participating in qualitative research studies

Understanding why socially marginalized individuals, such as lesbian, gay, bisexual, transgender and/or queer (LGBTQ+) people, participate in research can improve qualitative research designs, as well as social services and policies. In providing a participant-centered foundation, we interviewed 65 LGBTQ+ young adults and asked “Why are certain LGBTQ+ young adults motivated to engage in qualitative social science studies?” Many LGBTQ+ young people said they were committed to enacting social change and promoting advocacy. Participants also highlighted supporting scientific research and knowledge production. Finally, LGBTQ?+ participants engaged with research to introspectively analyze their identity development processes. These findings can facilitate access to socially vulnerable and underrepresented groups through a methodological focus on participant benefits.     

Loss of urban forest canopy and the effects on neighborhood soundscapes

Urban Ecosystems - The urban landscape constitutes a key aspect of human - nature interactions, as more than 60% of the world’s population resides in cities and their suburbs. This study...     

Effects of variations in water quantity and quality in the structure and functions of invertebrates’ community of a Mediterranean urban stream

Urban Ecosystems - Urban streams provide important ecosystem services to cities’ population, from the maintenance of urban biodiversity, temperature, humidity and air quality to improving...