256 research outputs found
Formative versus reflective measurement models: Two applications of formative measurement
This paper presents a framework that helps researchers to design and validate both formative and reflective measurement models. The framework draws from the existing literature and includes both theoretical and empirical considerations. Two important examples, one from international business and one from marketing, illustrate the use of the framework. Both examples concern constructs that are fundamental to theory-building in these disciplines, and constructs that most scholars measure reflectively. In contrast, applying the framework suggests that a formative measurement model may be more appropriate. These results reinforce the need for all researchers to justify, both theoretically and empirically, their choice of measurement model. Use of an incorrect measurement model undermines the content validity of constructs, misrepresents the structural relationships between them, and ultimately lowers the usefulness of management theories for business researchers and practitioners. The main contribution of this paper is to question the unthinking assumption of reflective measurement seen in much of the business literature
Conserved YKL-40 changes in mice and humans after postoperative delirium
Delirium is a common postoperative neurologic complication among older adults. Despite its prevalence (14%â50%) and likely association with inflammation, the exact mechanisms that underpin postoperative delirium are unclear. This project aimed to characterize systemic and central nervous system (CNS) inflammatory changes following surgery in mice and humans. Matched plasma and cerebrospinal fluid (CSF) samples from the âInvestigating Neuroinflammation Underlying Postoperative Brain Connectivity Changes, Postoperative Cognitive Dysfunction, Delirium in Older Adultsâ (INTUIT; NCT03273335) study were compared to murine endpoints. Delirium-like behavior was evaluated in aged mice using the 5-Choice Serial Reaction Time Test (5-CSRTT). Using a well established orthopedic surgical model in the FosTRAP reporter mouse we detected neuronal changes in the prefrontal cortex, an area implicated in attention, but notably not in the hippocampus. In aged mice, plasma interleukin-6 (IL-6), chitinase-3-like protein 1 (YKL-40), and neurofilament light chain (NfL) levels increased after orthopedic surgery, but hippocampal YKL-40 expression was decreased. Given the growing evidence for a YKL-40 role in delirium and other neurodegenerative conditions, we assayed human plasma and CSF samples. Plasma YKL-40 levels were similarly increased after surgery, with a trend toward a greater postoperative plasma YKL-40 increase in patients with delirium. However, YKL-40 levels in CSF decreased following surgery, which paralleled the findings in the mouse brain. Finally, we confirmed changes in the blood-brain barrier (BBB) as early as 9 h after surgery in mice, which warrants more detailed and acute evaluations of BBB integrity following surgery in humans. Together, these results provide a nuanced understanding of neuroimmune interactions underlying postoperative delirium in mice and humans, and highlight translational biomarkers to test potential cellular targets and mechanisms
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Drama and discounting in the relational dynamics of corporate social responsibility
Employing theoretical resources from Transactional Analysis (TA) and drawing from interviews with managers dealing with social or environmental issues in their role, we explain how CSR activity provides a context for dramas in which actors may ignore, or discount aspects of self, others, and the contexts of their work as they maintain and reproduce the roles of Rescuers, Persecutors and Victims. In doing so, we add to knowledge about CSR by providing an explanation for how the contradictions of CSR are avoided in practice even when actors may be aware of them. Specifically, we theorise how CSR work can produce dramatic stories where adversity is apparently overcome, whilst little is actually achieved at the social level. We also add to the range of psychoanalytic tools used to account for organisational behaviours, emphasising how TA can explain the relational dynamics of CSR
Ecto-5â˛-nucleotidase and intestinal ion secretion by enteropathogenic Escherichia coli
Enteropathogenic Escherichia coli (EPEC) triggers a large release of adenosine triphosphate (ATP) from host intestinal cells and the extracellular ATP is broken down to adenosine diphosphate (ADP), AMP, and adenosine. Adenosine is a potent secretagogue in the small and large intestine. We suspected that ecto-5â˛-nucleotidase (CD73, an intestinal enzyme) was a critical enzyme involved in the conversion of AMP to adenosine and in the pathogenesis of EPEC diarrhea. We developed a nonradioactive method for measuring ecto-5â˛-nucleotidase in cultured T84 cell monolayers based on the detection of phosphate release from 5â˛-AMP. EPEC infection triggered a release of ecto-5â˛-nucleotidase from the cell surface into the supernatant medium. EPEC-induced 5â˛-nucleotidase release was not correlated with host cell death but instead with activation of phosphatidylinositol-specific phospholipase C (PI-PLC). Ecto-5â˛-nucleotidase was susceptible to inhibition by zinc acetate and by Îą,β-methylene-adenosine diphosphate (Îą,β-methylene-ADP). In the Ussing chamber, these inhibitors could reverse the chloride secretory responses triggered by 5â˛-AMP. In addition, Îą,β-methylene-ADP and zinc blocked the ability of 5â˛-AMP to stimulate EPEC growth under nutrient-limited conditions in vitro. Ecto-5â˛-nucleotidase appears to be the major enzyme responsible for generation of adenosine from adenine nucleotides in the T84 cell line, and inhibitors of ecto-5â˛-nucleotidase, such as Îą,β-methylene-ADP and zinc, might be useful for treatment of the watery diarrhea produced by EPEC infection
The impact of changes in stakeholder salience on CSR activities in Russian energy firms: a contribution to the divergence / convergence debate
This empirical paper examines the drivers underpinning changes to socially-responsible behaviours in the Russian energy sector. Responding to recent requests to contextualise CSR research, we focus on the changing set of stakeholders and developments in their saliency as reflected in corporationsâ CSR activities. Based on interviews with more than thirty industry professionals, our findings suggest that Russian energy companiesâ CSR is strongly stakeholder driven, and organisations adapt their activities according to their dependence on the resources that these salient stakeholders possess.
We challenge the proposition that CSR in Russia arises from purely endogenous, historical, paternalism or neo-paternalism. We identify stakeholders that now shape CSR in the Russian energy sector, both endogenous (institutional and contextual forces relevant to the national business system) and exogenous (relating to the organisational field of the energy industry - international by nature). We thereby contribute to the convergence / divergence debate within CSR theory by demonstrating that both national business systems and the organisational field must be taken into account when analysing the forces that shape CSR strategies in any one country
Towards a Framework for Understanding Fairtrade Purchase Intention in the Mainstream Environment of Supermarkets
Š 2014, Springer Science+Business Media Dordrecht. Despite growing interest in ethical consumer behaviour research, ambiguity remains regarding what motivates consumers to purchase ethical products. While researchers largely attribute the growth of ethical consumerism to an increase in ethical consumer concerns and motivations, widened distribution (mainstreaming) of ethical products, such as fairtrade, questions these assumptions. A model that integrates both individual and societal values into the theory of planned behaviour is presented and empirically tested to challenge the assumption that ethical consumption is driven by ethical considerations alone. Using data sourced from fairtrade shoppers across the UK, structural equation modelling suggests that fairtrade purchase intention is driven by both societal and self-interest values. This dual value pathway helps address conceptual limitations inherent in the underlying assumptions of existing ethical purchasing behaviour m odels and helps advance understanding of consumersâ motivation to purchase ethical products
Demand for Zn2+ in Acid-Secreting Gastric Mucosa and Its Requirement for Intracellular Ca2+
Recent work has suggested that Zn(2+) plays a critical role in regulating acidity within the secretory compartments of isolated gastric glands. Here, we investigate the content, distribution and demand for Zn(2+) in gastric mucosa under baseline conditions and its regulation during secretory stimulation.Content and distribution of zinc were evaluated in sections of whole gastric mucosa using X-ray fluorescence microscopy. Significant stores of Zn(2+) were identified in neural elements of the muscularis, glandular areas enriched in parietal cells, and apical regions of the surface epithelium. In in vivo studies, extraction of the low abundance isotope, (70)Zn(2+), from the circulation was demonstrated in samples of mucosal tissue 24 hours or 72 hours after infusion (250 Âľg/kg). In in vitro studies, uptake of (70)Zn(2+) from media was demonstrated in isolated rabbit gastric glands following exposure to concentrations as low as 10 nM. In additional studies, demand of individual gastric parietal cells for Zn(2+) was monitored using the fluorescent zinc reporter, fluozin-3, by measuring increases in free intracellular concentrations of Zn(2+) {[Zn(2+)](i)} during exposure to standard extracellular concentrations of Zn(2+) (10 ÂľM) for standard intervals of time. Under resting conditions, demand for extracellular Zn(2+) increased with exposure to secretagogues (forskolin, carbachol/histamine) and under conditions associated with increased intracellular Ca(2+) {[Ca(2+)](i)}. Uptake of Zn(2+) was abolished following removal of extracellular Ca(2+) or depletion of intracellular Ca(2+) stores, suggesting that demand for extracellular Zn(2+) increases and depends on influx of extracellular Ca(2+).This study is the first to characterize the content and distribution of Zn(2+) in an organ of the gastrointestinal tract. Our findings offer the novel interpretation, that Ca(2+) integrates basolateral demand for Zn(2+) with stimulation of secretion of HCl into the lumen of the gastric gland. Similar connections may be detectable in other secretory cells and tissues
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