What explains differences in firms’ abilities to acquire competitive capabilities? In this paper we propose that a firm’s embeddedness in a network of ties is an important source of variation in the acquisition of competitive capabilities. We argue that firms in geographical clusters that maintain networks rich in bridging ties and sustain ties to regional institutions are well-positioned to access new information, ideas, and opportunities. Hypotheses based on these ideas were tested on a stratified random sample of 227 job shop manufacturers located in the Midwest United States. Data were gathered using a mailed questionnaire. Results from structural equation modeling broadly support the embeddedness hypotheses and suggest a number of insights about the link between firms’ networks and the acquisition of competitive capabilities. Copyright © 1999 John Wiley & Sons, Ltd.

https://www.jstor.org/stable/pdfplus/3094082.pdf

Bridging ties: a source of firm heterogeneity in competitive capabilities

Attention-deficit hyperactivity disorder (ADHD) is a disorder of inattention, impulsivity, and hyperactivity that affects 8-12% of children worldwide. Although the rate of ADHD falls with age, at least half of children with the disorder will have impairing symptoms in adulthood. Twin, adoption, and molecular genetic studies show ADHD to be highly heritable, and other findings have recorded obstetric complications and psychosocial adversity as predisposing risk factors. Converging evidence from animal and human studies implicates the dysregulation of frontal-subcortical-cerebellar catecholaminergic circuits in the pathophysiology of ADHD, and molecular imaging studies suggest that abnormalities of the dopamine transporter lead to impaired neurotransmission. Studies during the past decade have shown the safety and effectiveness of new non-stimulant drugs and long-acting formulations of methylphenidate and amfetamine. Other investigations have also clarified the appropriate role of targeted psychosocial treatments in the context of ongoing pharmacotherapy.

SeminarAttention-deficit hyperactivity disorder

Scholars routinely make claims that presuppose the validity of the observations and measurements that operationalize their concepts. Yet, despite recent advances in political science methods, surprisingly little attention has been devoted to measurement validity. We address this gap by exploring four themes. First, we seek to establish a shared framework that allows quantitative and qualitative scholars to assess more effectively, and communicate about, issues of valid measurement. Second, we underscore the need to draw a clear distinction between measurement issues and disputes about concepts. Third, we discuss the contextual specificity of measurement claims, exploring a variety of measurement strategies that seek to combine generality and validity by devoting greater attention to context. Fourth, we address the proliferation of terms for alternative measurement validation procedures and offer an account of the three main types of validation most relevant to political scientists.

Measurement Validity: A Shared Standard for Qualitative and Quantitative Research

The author examines the determinants of opportunistic behavior in an interfirm relationship. Data from a franchise setting are examined for the effects of inter-organizational structure and interfi...

An Empirical Investigation of Some Antecedents of Opportunism in a Marketing Channel

The reason for the high frequency of depression and anxiety in Parkinson's disease is poorly understood. Degeneration of neurotransmitter systems other than dopamine might play a specific role in the occurrence of these affective disorders. We used [11C]RTI-32 PET, an in vivo marker of both dopamine and noradrenaline transporter binding, to localize differences between depressed and non-depressed patients. We studied eight and 12 Parkinson's disease patients with and without a history of depression matched for age, disease duration and doses of antiparkinsonian medication. The depressed Parkinson's disease cohort had lower [11C]RTI-32 binding than non-depressed Parkinson's disease cases in the locus coeruleus and in several regions of the limbic system including the anterior cingulate cortex, the thalamus, the amygdala and the ventral striatum. Exploratory analyses revealed that the severity of anxiety in the Parkinson's disease patients was inversely correlated with the [11C]RTI-32 binding in most of these regions and apathy was inversely correlated with [11C]RTI-32 binding in the ventral striatum. These results suggest that depression and anxiety in Parkinson's disease might be associated with a specific loss of dopamine and noradrenaline innervation in the limbic system.

/pdf/depression-in-parkinson-s-disease-loss-of-dopamine-and-3r1zfj5rar.pdf

Depression in Parkinson's disease: loss of dopamine and noradrenaline innervation in the limbic system.

Definition: To what extent does the study allow us to draw conclusions about a causal effect between two or more constructs? Issues: Selection, maturation, history, mortality, testing, regression towrd the mean, selection by maturation, treatment by mortality, treatment by testing, measured treatment variables Increase: Eliminate the threats, above all do experimental manipulations, random assignment, and counterbalancing.

Kishi G

Papers

Reliability and validity