University of Memphis

About: University of Memphis is a education organization based out in Memphis, Tennessee, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 7710 authors who have published 20082 publications receiving 611618 citations. The organization is also known as: U of M.

Strategic change in the turnaround process: theory and empirical evidence

Abstract: Early corporate turnaround theorists argued that strategic reorientations are central to the recovery process at many declining firms. However, subsequent large-sample empirical studies have reported that performance turnarounds for declining firms are primarily associated with cutback actions that increase efficiency, thus creating a gap between theory and empirical findings. We close this gap by presenting and empirically supporting a model proposing that the extent of strategic change initiated in a successful turnaround varies systematically with a declining firm’s need and capacity to reorient its strategy. Based on our model, we offer explanations for why past large-sample researchers were not able to verify the role of strategic change in the turnaround process and we reassert the adaptive role that strategic reorientations have in the turnaround attempts of declining firms with weak strategic positions. © 1997 by John Wiley & Sons, Ltd.

Cryptochrome mediates circadian regulation of cAMP signaling and hepatic gluconeogenesis

Abstract: During fasting, mammals maintain normal glucose homeostasis by stimulating hepatic gluconeogenesis. Elevations in circulating glucagon and epinephrine, two hormones that activate hepatic gluconeogenesis, trigger the cAMP-mediated phosphorylation of cAMP response element-binding protein (Creb) and dephosphorylation of the Creb-regulated transcription coactivator-2 (Crtc2)--two key transcriptional regulators of this process. Although the underlying mechanism is unclear, hepatic gluconeogenesis is also regulated by the circadian clock, which coordinates glucose metabolism with changes in the external environment. Circadian control of gene expression is achieved by two transcriptional activators, Clock and Bmal1, which stimulate cryptochrome (Cry1 and Cry2) and Period (Per1, Per2 and Per3) repressors that feed back on Clock-Bmal1 activity. Here we show that Creb activity during fasting is modulated by Cry1 and Cry2, which are rhythmically expressed in the liver. Cry1 expression was elevated during the night-day transition, when it reduced fasting gluconeogenic gene expression by blocking glucagon-mediated increases in intracellular cAMP concentrations and in the protein kinase A-mediated phosphorylation of Creb. In biochemical reconstitution studies, we found that Cry1 inhibited accumulation of cAMP in response to G protein-coupled receptor (GPCR) activation but not to forskolin, a direct activator of adenyl cyclase. Cry proteins seemed to modulate GPCR activity directly through interaction with G(s)α. As hepatic overexpression of Cry1 lowered blood glucose concentrations and improved insulin sensitivity in insulin-resistant db/db mice, our results suggest that compounds that enhance cryptochrome activity may provide therapeutic benefit to individuals with type 2 diabetes.

Actigraphy validation with insomnia.

Abstract: Study Objective: Actigraphy, a method of inferring sleep from the presence or absence of wrist movement, has been well validated against polysomnography in trials with people without insomnia. However, the small amount of literature on validation with insomniacs has revealed an actigraphy bias toward overscoring sleep. The current validation trial with insomniacs used the largest number of subjects to date in such research and attracted participants with diverse demographic characteristics. Design: People with insomnia slept 1 night in the laboratory while simultaneously being monitored by polysomnography, actigraphy (high-sensitivity algorithm of the Mini Mitter AW64 Actiwatch™), and morning sleep diary. Setting: Sleep disorders center. Participants: Participants were 57 volunteers from the community, 26 men and 31 women, ranging in age from 21 to 87 years. All participants satisfied conservative criteria for insomnia. The sample included subjects with primary insomnia, subjects with comorbid insomnia, and hypnotic users with current insomnia complaints. Interventions: N/A. Measurements and Results: Actigraphy was successfully validated on 4 measures of sleep pattern—number of awakenings, wake time after sleep onset, total sleep time, and sleep efficiency percentage—based on nonsignificant mean differences and significant correlation between actigraphy and polysomnography. Sleep-onset latency with actigraphy was not significantly different from polysomnography but was weakly correlated with polysomnography. Hypnotic use contributed to actigraphic overscoring of sleep. Conclusions: Actigraphy proved to be a satisfactory objective measure of sleep on 4 of 5 sleep parameters, but these results are specific to this particular instrument using this particular algorithm and should not be construed as a blanket endorsement of actigraphy for measuring insomnia.