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Heavy Use (heavy + use)
Selected AbstractsTesting for cannabis in the work-place: a review of the evidenceADDICTION, Issue 3 2010Scott Macdonald ABSTRACT Background Urinalysis testing in the work-place has been adopted widely by employers in the United States to deter employee drug use and promote ,drug-free' work-places. In other countries, such as Canada, testing is focused more narrowly on identifying employees whose drug use puts the safety of others at risk. Aims We review 20 years of published literature on questions relevant to the objectives of work-place drug testing (WPDT), with a special emphasis on cannabis, the most commonly detected drug. Results We conclude (i) that the acute effects of smoking cannabis impair performance for a period of about 4 hours; (ii) long-term heavy use of cannabis can impair cognitive ability, but it is not clear that heavy cannabis users represent a meaningful job safety risk unless using before work or on the job; (iii) urine tests have poor validity and low sensitivity to detect employees who represent a safety risk; (iv) drug testing is related to reductions in the prevalence of cannabis positive tests among employees, but this might not translate into fewer cannabis users; and (v) urinalysis has not been shown to have a meaningful impact on job injury/accident rates. Conclusions Urinalysis testing is not recommended as a diagnostic tool to identify employees who represent a job safety risk from cannabis use. Blood testing for active tetrahydrocannabinol (THC) can be considered by employers who wish to identify employees whose performance may be impaired by their cannabis use. [source] Consequences of chronic ketamine self-administration upon neurocognitive function and psychological wellbeing: a 1-year longitudinal studyADDICTION, Issue 1 2010Celia J. A. Morgan ABSTRACT Background ,Recreational' use of ketamine is spreading rapidly among young people. In healthy individuals an acute dose of the N-methyl D-aspartate (NMDA) receptor antagonist ketamine induces marked psychosis-like effects and cognitive impairments, but little is known about the long-term effects of the drug. Aims To evaluate the long-term neuropsychiatric or cognitive consequences. Methods A total of 150 individuals were assessed, 30 in each of five groups: frequent ketamine users, infrequent ketamine users, abstinent users, polydrug controls and non-users of illicit drugs. Twelve months later, 80% of these individuals were re-tested. Results Cognitive deficits were mainly observed only in frequent users. In this group, increasing ketamine use over the year was correlated with decreasing performance on spatial working memory and pattern recognition memory tasks. Assessments of psychological wellbeing showed greater dissociative symptoms in frequent users and a dose,response effect on delusional symptoms, with frequent users scoring higher than infrequent, abstinent users and non-users, respectively. Both frequent and abstinent using groups showed increased depression scores over the 12 months. Conclusions These findings imply that heavy use of ketamine is harmful to aspects of both cognitive function and psychological wellbeing. Health education campaigns need to raise awareness among young people and clinicians about these negative consequences of ketamine use. [source] Saccadic peak velocity and EEG as end-points for a serotonergic challenge testHUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 2 2002Harm J. Gijsman Abstract We previously reported that a single dose of the serotonin receptor agonist meta-chlorophenylpiperazine increased the peak velocity of saccadic eye movements and decreased low-frequency electroencephalographic activity. Methods We administered a single dose of the serotonin releaser dexfenfluramine in a double blind, placebo controlled randomised cross-over design and measured saccadic eye movements and EEG every hour up to 6,h. Subjects were 62 males (18,30 years) with a history of no, moderate or heavy use of ecstasy tablets. Results Dexfenfluramine increased saccadic peak velocity and decreased alpha, delta and theta electroencephalographic activity, the latter predominantly in heavy users of ecstasy. Conclusions This study supports the idea that saccadic peak velocity and EEG can be useful endpoints of a serotonergic challenge. This could be an important anatomical extension of these end-points, which until now were limited to the effect on hypothalamic serotonergic projections. Copyright © 2002 John Wiley & Sons, Ltd. [source] Energy efficiency improvement strategies for a diesel engine in low-temperature combustionINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 1 2009Ming Zheng Abstract The lowered combustion temperature in diesel engines is capable of reducing nitrogen oxides and soot simultaneously, which can be implemented by the heavy use of exhaust gas recirculation (EGR) or the homogeneous charge compression ignition (HCCI) type of combustion. However, the fuel efficiency of the low-temperature combustion (LTC) cycles is commonly compromised by the high levels of hydrocarbon and carbon monoxide emissions. More seriously, the scheduling of fuel delivery in HCCI engines has lesser leverage on the exact timing of auto-ignition that may even occur before the compression stroke is completed, which may cause excessive efficiency reduction and combustion roughness. New LTC control strategies have been explored experimentally to achieve ultralow emissions under independently controlled EGR, intake boost, exhaust backpressure, and multi-event fuel-injection events. Empirical comparisons have been made between the fuel efficiencies of LTC and conventional diesel cycles. Preliminary adaptive control strategies based on cylinder pressure characteristics have been implemented to enable and stabilize the LTC when heavy EGR is applied. The impact of heat-release phasing, duration, shaping, and splitting on the thermal efficiency has also been analyzed with engine cycle simulations. This research intends to identify the major parameters that affect diesel LTC engine thermal efficiency. Copyright © 2008 John Wiley & Sons, Ltd. [source] Graph-based tools for re-engineeringJOURNAL OF SOFTWARE MAINTENANCE AND EVOLUTION: RESEARCH AND PRACTICE, Issue 4 2002Katja Cremer Abstract Maintenance of legacy systems is a challenging task. Often, only the source code is still available, while design or requirements documents have been lost or have not been kept up-to-date with the actual implementation. In particular, this applies to many business applications which are run on a mainframe computer and are written in COBOL. Many companies are confronted with the difficult task of migrating these systems to a client/server architecture with clients running on PCs and servers running on the mainframe. REforDI (REengineering for DIstribution) is a graph-based environment supporting this task. REforDI provides integrated code analysis, re-design, and code transformation for COBOL applications. To prepare the application for distribution, REforDI assists in the transition to an object-based architecture, according to which the source code is subsequently transformed into Object COBOL. Internally, REforDI makes heavy use of generators to reduce the implementation effort and thus to enhance adaptability. In particular, graph-based tools for re-engineering are generated from a formal specification which is based on programmed graph transformations. Copyright © 2002 John Wiley & Sons, Ltd. [source] Behavioral adaptations to heat stress and water scarcity in white-faced capuchins (Cebus capucinus) in Santa Rosa National Park, Costa RicaAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 1 2009Fernando A. Campos Abstract We examined thermoregulatory behaviors in a wild population of white-faced capuchins (Cebus capucinus) inhabiting a highly seasonal dry forest in Santa Rosa National Park (SRNP), Costa Rica. The dry season in SRNP lasts ,5 months and is characterized by high ambient temperatures regularly exceeding 37°C, low relative humidity, and the near absence of precipitation. This study demonstrates that capuchins rest more and travel shorter distances during the hottest and driest hours of the day, and suggests that they extend their tongues to lower body temperature via evaporative cooling. Seasonal weather patterns and group movement data reported here are based on 940 h of observations on three social groups of capuchins (wet season: 370 h, dry season: 570 h). In the dry season, the proportion of time spent resting increased at higher temperatures whereas the proportion of time spent traveling decreased. Distance traveled between location points taken at half-hour intervals decreased significantly as temperature increased, although the correlation was not strong. Capuchins exposed their tongues during hot, dry, windy conditions, and this behavior was much more frequent in the dry season. Temperature was significantly higher and humidity significantly lower for "tongue-out" events than expected for a random event in the dry season. Finally, as surface water became scarce, home-range areas of heavy use became increasingly centered on the remaining permanent water sources. These results suggest that heat stress and water scarcity are significant influences on the behavior of capuchins in hot, dry conditions. Am J Phys Anthropol, 2009. © 2008 Wiley-Liss, Inc. [source] Responses of squirrel monkeys to seasonal changes in food availability in an eastern Amazonian forestAMERICAN JOURNAL OF PRIMATOLOGY, Issue 2 2007Anita I. Stone Abstract Tropical forests are characterized by marked temporal and spatial variation in productivity, and many primates face foraging problems associated with seasonal shifts in fruit availability. In this study, I examined seasonal changes in diet and foraging behaviors of two groups of squirrel monkeys (Saimiri sciureus), studied for 12 months in Eastern Brazilian Amazonia, an area characterized by seasonal rainfall. Squirrel monkeys were primarily insectivorous (79% of feeding and foraging time), with fruit consumption highest during the rainy season. Although monkeys fed from 68 plant species, fruit of Attalea maripa palms accounted for 28% of annual fruit-feeding records. Dietary shifts in the dry season were correlated with a decline in ripe A. maripa fruits. Despite pronounced seasonal variation in rainfall and fruit abundance, foraging efficiency, travel time, and distance traveled remained stable between seasons. Instead, squirrel monkeys at this Eastern Amazonian site primarily dealt with the seasonal decline in fruit by showing dietary flexibility. Consumption of insects, flowers, and exudates increased during the dry season. In particular, their foraging behavior at this time strongly resembled that of tamarins (Saguinus sp.) and consisted of heavy use of seed-pod exudates and specialized foraging on large-bodied orthopterans near the forest floor. Comparisons with squirrel monkeys at other locations indicate that, across their geographic range, Saimiri use a variety of behavioral tactics during reduced periods of fruit availability. Am. J. Primatol. 69:1,16, 2007. © 2006 Wiley-Liss, Inc. [source] Geographical information systems-based models for offshore floating marine fish cage aquaculture site selection in Tenerife, Canary IslandsAQUACULTURE RESEARCH, Issue 10 2005Oscar M Pérez Abstract The present study focuses on the development of a standard methodology for selection of suitable sites for offshore (exposed) marine fish-cage farming (floating cages) of seabream (Sparus aurata) and seabass (Dicentrarchus labrax) in an island environment, using Tenerife as an example. Site selection is a key factor in any aquaculture operation, affecting both success and sustainability and can solve conflicts between different activities, making a rational use of the coastal space. Site selection was achieved by using geographical information systems (GIS)-based models and related technology to support the decision-making process. The framework for spatial multicriteria decision analysis used in this study began with a recognition and definition of the decision problem. Subsequently, 31 production functions (factors and constraints) were identified, defined and subdivided into eight submodels. These were then integrated into a GIS database in the form of thematic layers and later scored for standardization. At this stage, the database was verified by field sampling to establish the quality of data used. The decision maker's preferences were incorporated into the decision model by assigning weights of relative importance to the evaluation under consideration. These, together with the thematic layers, were incorporated using multicriteria evaluation techniques and simple overlays to provide an overall assessment of possible alternatives. The integration, manipulation and presentation of the results by means of GIS-based models in this sequential and logical flow of steps proved to be very effective for helping the decision-making process of site selection. Tenerife has very favourable environmental conditions for culture of marine fish and there are no totally unsuitable sites for cage farming identified in this study. On the other hand, there are few very suitable sites (high scores) either, principally due to the heavy use of the coastline and the conflicts between different users. From the 228 km2 of available area for siting cages in the coastal regions with depth less than 50 m, the total area suitable for siting cages (scores 6,8) was 37 km2. There are only 0.51 km2 of very suitable areas (score 8) and approximately 5.37 km2 of suitable (score 7), most of these being located in the southeast of the island. These relatively small areas of suitability should be put into the context of the wider use of the coastal environment around Tenerife. [source] | |||||||||||||