Virginia Commonwealth University

About: Virginia Commonwealth University is a education organization based out in Richmond, Virginia, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 23822 authors who have published 49587 publications receiving 1787046 citations. The organization is also known as: VCU.

A 9,000-year record of Chagas' disease

Abstract: Tissue specimens from 283 principally spontaneously (naturally) desiccated human mummies from coastal and low valley sites in northern Chile and southern Peru were tested with a DNA probe directed at a kinetoplast DNA segment of Trypanosoma cruzi. The time interval spanned by the eleven major cultural groups represented in the sample ranged from ≈9,000 years B.P. (7050 B.C.) to approximately the time of the Spanish conquest, ≈450 B.P. (≈1500 A.D.). Forty-one percent of the tissue extracts, amplified by the PCR reacted positively (i.e., hybridized) with the probe. Prevalence patterns demonstrated no statistically significant differences among the individual cultural groups, nor among subgroups compared on the basis of age, sex, or weight of specimen tested. These results suggest that the sylvatic (animal-infected) cycle of Chagas' disease was probably well established at the time that the earliest humans (members of the Chinchorro culture) first peopled this segment of the Andean coast and inadvertently joined the many other mammal species acting as hosts for this parasite.

Emotional Labor at a Crossroads: Where Do We Go from Here?

Abstract: Three decades after its introduction as a concept, emotional labor—regulating emotions as part of the work role—is fully on the map in organizational behavior and organizational psychology. As research has accelerated, roadblocks, such as fuzzy construct conceptualizations, assumed but untested processes, and methodological stagnation, have emerged. To provide direction to new scholars and suggestions to seasoned emotional labor researchers, we review theoretical perspectives and evidence for emotional labor and its (a) construct development and measurement, (b) chronic and momentary determinants, (c) prediction of employee well-being, and (d) influence on organizational performance. On this path, we introduce emotional labor as a dynamic integration of three components (i.e., emotional requirements, emotion regulation, and emotion performance), interpret personal and organizational moderators, and point to innovative new methodological approaches. Overall, we provide a new road map to jump-start the fiel...

Examining the Role of Social Media in Effective Crisis Management: The Effects of Crisis Origin, Information Form, and Source on Publics’ Crisis Responses

Abstract: Publics increasingly use social media during crises and, consequently, crisis communication professionals need to understand how to strategically optimize these tools. Despite this need, there is scarce theory-grounded research to understand key factors that affect how publics consume crisis information via social media compared to other sources. To fill this gap, an emerging model helps crisis managers understand how publics produce, consume, and/or share crisis information via social media and other sources: the social-mediated crisis communication model (SMCC). This study tests essential components of the SMCC model through a 3 (crisis information form) x 2 (crisis information source) x 2 (crisis origin) mixed-design experiment (N = 338). The findings indicate the key role of crisis origin in affecting publics’ preferred information form (social media, traditional media, or word-of-mouth communication) and source (organization in crisis or third party), which influences how publics anticipate an organi...

Mannitol causes compensatory cerebral vasoconstriction and vasodilation in response to blood viscosity changes.

Abstract: There is no proof that osmotic agents such as mannitol lower intracranial pressure (ICP) by decreasing brain water content. An alternative mechanism might be a reduction in cerebral blood volume through vasoconstriction. Mannitol, by decreasing blood viscosity, would tend to enhance cerebral blood flow (CBF), but the cerebral vessels would constrict to keep CBF relatively constant, analogous to pressure autoregulation. The cranial window technique was used in this study to measure the pial arteriolar diameter in cats, together with blood viscosity and ICP changes after an intravenous bolus of 1 gm/kg of mannitol. Blood viscosity decreased immediately; the greatest decrease (23%) occurred at 10 minutes, and at 75 minutes there was a "rebound" increase of 10%. Vessel diameters decreased concomitantly, the largest decrease being 12% at 10 minutes, which is exactly the same as the 12% decrease in diameter associated with pronounced hyperventilation (PaCO2 30 to 19 mm Hg) in the same vessels; at 75 minutes vessel diameter increased by 12%. With hyperventilation, ICP was decreased by 26%; 10 minutes after mannitol was given, ICP decreased by 28%, and at 75 minutes it showed a rebound increase of 40%. The correlation between blood viscosity and vessel diameter and between vessel diameter and ICP was very high. An alternative explanation is offered for the effect of mannitol on ICP, the time course of ICP changes, "rebound effect," and the absence of influence on CBF, all with one mechanism.