3,414 research outputs found
Socio-Economic Sourcing: Benefits of Small Business Set-Asides in Public Procurement
Purpose
Small businesses are critical to economic health and encouraged in government spending by set-asides – annual small business sourcing goals that often are not attained. Little research has explored the negative and risky stigmas associated with small business sourcing. Design/methodology/approach
This research explores reduced transaction costs of small business sourcing to government buyers. A survey of 350 government source selections reveals lower transaction costs derived from lower perceived risk of receiving a bid protest and via more efficient source selection processes. Findings
Contrary to common bias, the performance level of small businesses is no less than that of large business. Thus, small businesses engender lower transaction costs for correcting supplier’s performance. On the basis of these findings, managerial and theoretical implications are discussed
Consumer Product Safety Regulation in the United States and the United Kingdom: The Case of Bicycles
We study the effects of bicycle safety regulations in both the United States and the United Kingdom on bicycle accident rates for various population age groups. We find small, statistically significant decreases in the accident rates as the stock of bicycles increases its compliance with the regulations. This result is independent of country, season, and trend effects and holds across a range of age groups. The results run counter to those in similar studies. This appears to reflect our focus on a specific standard, rather than on broad enabling legislation, and the longer time series available.
Combining noninvasive brain stimulation with behavioral pharmacology methods to study mechanisms of substance use disorder
Psychotropic drugs and transcranial magnetic stimulation (TMS) are effective for treating certain psychiatric conditions. Drugs and TMS have also been used as tools to explore the relationship between brain function and behavior in humans. Combining centrally acting drugs and TMS has proven useful for characterizing the neural basis of movement. This combined intervention approach also holds promise for improving our understanding of the mechanisms underlying disordered behavior associated with psychiatric conditions, including addiction, though challenges exist. For example, altered neocortical function has been implicated in substance use disorder, but the relationship between acute neuromodulation of neocortex with TMS and direct effects on addiction-related behaviors is not well established. We propose that the combination of human behavioral pharmacology methods with TMS can be leveraged to help establish these links. This perspective article describes an ongoing study that combines the administration of delta-9-tetrahydrocannabinol (THC), the main psychoactive compound in cannabis, with neuroimaging-guided TMS in individuals with problematic cannabis use. The study examines the impact of the left dorsolateral prefrontal cortex (DLPFC) stimulation on cognitive outcomes impacted by THC intoxication, including the subjective response to THC and the impairing effects of THC on behavioral performance. A framework for integrating TMS with human behavioral pharmacology methods, along with key details of the study design, are presented. We also discuss challenges, alternatives, and future directions
EXISTENCE OF UNIQUE LIMITING PROBABILITY VECTORS IN STOCHASTIC PROCESSES WITH MULTIPLE TRANSITION MATRICES
Concepts associated with stochastic process containing multiple transition matricies are discussed. It is proved that under certain conditions, a process with m transition matrices has m unique limiting probability vectors. This result extends the notion of discrete Markov processes to problems with intrayear and interyear dynamics. An example using a large DP model illustrates the usefulness of the concepts developed to applied problems.Research Methods/ Statistical Methods,
Neurophysiological Capacity in a Working Memory Task Differentiates Dependent from Nondependent Heavy Drinkers and Controls
Background—Determining the brain-behavior profiles that differentiate heavy drinkers who are and are not alcohol dependent will inform treatment efforts. Working memory is linked to substance use disorders and can serve as a representation of the demand placed on the neurophysiology associated with cognitive control.
Methods—Behavior and brain activity (via fMRI) were recorded during an N-Back working memory task in controls (CTRL), nondependent heavy drinkers (A-ND) and dependent heavy drinkers (A-D). Typical and novel step-wise analyses examined profiles of working memory load and increasing task demand, respectively.
Results—Performance was significantly decreased in A-D during high working memory load (2-Back), compared to CTRL and A-ND. Analysis of brain activity during high load (0-Back vs. 2-Back) showed greater responses in the dorsal lateral and medial prefrontal cortices of A-D than CTRL, suggesting increased but failed compensation. The step-wise analysis revealed that the transition to Low Demand (0-Back to 1-Back) was associated with robust increases and decreases in cognitive control and default-mode brain regions, respectively, in A-D and A-ND but not CTRL. The transition to High Demand (1-Back to 2-Back) resulted in additional engagement of these networks in A-ND and CTRL, but not A-D.
Conclusion—Heavy drinkers engaged working memory neural networks at lower demand than controls. As demand increased, nondependent heavy drinkers maintained control performance but relied on additional neurophysiological resources, and dependent heavy drinkers did not display further resource engagement and had poorer performance. These results support targeting these brain areas for treatment interventions
A Multi-Sensor Array to Study Flight Dynamics, Atmospheric Pollution and Gas Composition in Earth’s Atmosphere
Expression of Lipogenic Factors Galectin-12, Resistin, SREBP-1, and SCD in Human Sebaceous Glands and Cultured Sebocytes
The transcription factors CCAAT enhancer-binding protein α, β, and δ, and peroxisome proliferator-activated receptor γ are known to be crucial to the differentiation of adipocytes and are expressed in sebaceous gland cells. As lipogenesis is key to both adipocyte and sebocyte differentiation we hypothesize that sebocytes follow a similar program of differentiation to adipocytes. We have investigated the expression of known adipogenic factors resistin, galectin-12, sterol response –element-binding protein–1 (SREBP-1) and stearoyl-CoA desaturase in the immortalized sebaceous gland cell line SZ95 and whole skin. Reverse transcriptase-PCR analysis showed the expression of galectin-12, resistin, SREBP-1, and stearoyl-CoA desaturase mRNAs in SZ95 sebocytes. Immunoreactivity was observed for galectin-12 and SREBP-1 in the nuclei and resistin in the cytoplasm of basal sebocytes, and stearoyl CoA desaturase in the cytoplasm of basal and luminal sebocytes of human scalp skin. Expression of galectin-12, resistin, and SREBP-1 in SZ95 sebocytes was confirmed by Western blot analysis. These data provide further evidence that pathways of differentiation in adipocytes and sebocytes could be similar and therefore further understanding of sebaceous gland differentiation and lipogenesis and potential therapies for sebaceous gland disorders may be obtained from our knowledge of adipocyte differentiation
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