Exposure to galactic cosmic radiation is a potential health risk in long-term space travel and represents a significant risk to the central nervous system. The most harmful component of galactic cosmic radiation is the HZE [high mass, highly charged (Z), high energy] particles, e.g., (56)Fe particle. In previous ground-based experiments, exposure to doses of HZE-particle radiation that an astronaut will receive on a deep space mission (i.e., ∼20 cGy) resulted in pronounced deficits in hippocampus-dependent learning and memory in rodents. Neurocognitive tasks that are dependent upon other regions of the brain, such as the striatum, are also impaired after exposure to low HZE-particle doses. These data raise the possibility that neurocognitive tasks regulated by the prefrontal cortex could also be impaired after exposure to mission relevant HZE-particle doses, which may prevent astronauts from performing complex executive functions. To assess the effects of mission relevant (20 cGy) doses of 1 GeV/u (56)Fe particles on executive function, male Wistar rats received either sham treatment or were irradiated and tested 3 months later for their ability to perform attentional set shifting. Compared to the controls, rats that received 20 cGy of 1 GeV/u (56)Fe particles showed significant impairments in their ability to complete the attentional set-shifting test, with only 17% of irradiated rats completing all stages as opposed to 78% of the control rats. The majority of failures (60%) occurred at the first reversal stage, and half of the remaining animals failed at the extra-dimensional shift phase of the studies. The irradiated rats that managed to complete the tasks did so with approximately the same ease as did the control rats. These observations suggest that exposure to mission relevant doses of 1 GeV/u (56)Fe particles results in the loss of functionality in several regions of the cortex: medical prefrontal cortex, anterior cingulated cortex, posterior cingulated cortex and the basal forebrain. Our observation that 20 cGy of 1 GeV/u (56)Fe particles is sufficient to impair the ability of rats to conduct attentional set-shifting raises the possibility that astronauts on prolonged deep space exploratory missions could subsequently develop deficits in executive function.
PurposeThis study seeks to determine differences between recruitment processes and methods and training practices used in small and large businesses in the retailing, manufacturing, and tourism sectors in an emerging economy, Barbados.Design/methodology/approachThe research utilized a quantitative survey covering 49 retailing, manufacturing and tourism‐oriented organizations to ascertain whether small organizations practice the procedures and methods outlined in the prescriptive literature on recruitment and training compared with large organizations. Institutional theory and resource‐based view informed the research.FindingsIt was found that recruitment processes and methods and training practices vary among small and large organizations. It suggests that, in Barbados, small businesses are likely to rely on informal recruitment methods and informal training practices compared with large businesses.Research limitations/implicationsThis study is only conducted across the retailing, manufacturing and tourism sectors in Barbados. The findings may have implications for management in other sectors, and small and large businesses in emerging economies.Practical implicationsThe results provide academics and managers in both large and small businesses with insights into recruitment and training practices in small and large businesses in an emerging economy.Originality/valueThis paper contributes to the limited research done on recruitment and training activities among small‐sized and large‐sized firms in the English‐speaking Caribbean.
A rapid and sensitive LC-MS/MS method was developed and validated for the simultaneous determination of buprenorphine and its three metabolites (buprenorphine glucuronide, norbuprenorphine and norbuprenorphine glucuronide) as well as naloxone and its metabolite naloxone glucuronide in the rat plasma. A hydrophilic interaction chromatography column and a mobile phase containing acetonitrile and ammonium formate buffer (pH 3.5) were used for the chromatographic separation. Mass spectrometric detection was achieved by an electrospray ionization source in the positive mode coupled to a triple quadrupole mass analyzer. The calibration curves for the six analytes displayed good linearity over the concentration range 1.0 or 5.0-1000 ng/mL. The intra and inter-day precision (CV) ranged from 2.68 to 16.4% and from 9.02 to 14.5%, respectively. The intra- and inter-day accuracy (bias) ranged from -14.2 to 15.2% and from -9.00 to 4.80%, respectively. The extraction recoveries for all the analytes ranged from 55 to 86.9%. The LC-MS/MS method was successfully applied to a pharmacokinetic study of buprenorphine-naloxone combination in rats.
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