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981.
Numair Ahmed Andrew Carlson John A. Rogers Placid M. Ferreira 《Journal of Manufacturing Processes》2012,14(2):90-97
This paper demonstrates the use of a flexible instrumented stamp to enable automated micro transfer printing as a route to large-area, deterministic assembly of microstructured device components or ‘inks’. The ability to instrument the stamp, a critical component for retrieval and placement of a micro device, to detect contact and monitor localized forces during critical events in the printing process not only allows for the development of a robust manufacturing process, but also for a unique vantage point from which to study fundamental issues and phenomena associated with adhesion and delamination of thin films from a variety of substrate materials. This paper presents basic design analysis on the requirements of the cantilevers for compatibility with a typical transfer printing environment. Off-the-shelf thin film strain gages are integrated with a thin elastomeric post as a preliminary prototype and the feasibility of transfer printing with it is demonstrated. Further, the set-up is calibrated to produce force signals for event detection and in situ diagnosis of the process. 相似文献
982.
983.
Does safety climate moderate the influence of staffing adequacy and work conditions on nurse injuries? 总被引:1,自引:0,他引:1
Mark BA Hughes LC Belyea M Chang Y Hofmann D Jones CB Bacon CT 《Journal of Safety Research》2007,38(4):431-446
PROBLEM: Hospital nurses have one of the highest work-related injury rates in the United States. Yet, approaches to improving employee safety have generally focused on attempts to modify individual behavior through enforced compliance with safety rules and mandatory participation in safety training. We examined a theoretical model that investigated the impact on nurse injuries (back injuries and needlesticks) of critical structural variables (staffing adequacy, work engagement, and work conditions) and further tested whether safety climate moderated these effects. METHOD: A longitudinal, non-experimental, organizational study, conducted in 281 medical-surgical units in 143 general acute care hospitals in the United States. RESULTS: Work engagement and work conditions were positively related to safety climate, but not directly to nurse back injuries or needlesticks. Safety climate moderated the relationship between work engagement and needlesticks, while safety climate moderated the effect of work conditions on both needlesticks and back injuries, although in unexpected ways. DISCUSSION AND IMPACT ON INDUSTRY: Our findings suggest that positive work engagement and work conditions contribute to enhanced safety climate and can reduce nurse injuries. 相似文献
984.
Power matters in closing the phenotyping gap 总被引:1,自引:0,他引:1
Meyer CW Elvert R Scherag A Ehrhardt N Gailus-Durner V Fuchs H Schäfer H Hrabé de Angelis M Heldmaier G Klingenspor M 《Die Naturwissenschaften》2007,94(5):401-406
Much of our understanding of physiology and metabolism is derived from investigating mouse mutants and transgenic mice, and
open-access platforms for standardized mouse phenotyping such as the German Mouse Clinic (GMC) are currently viewed as one
powerful tool for identifying novel gene-function relationships. Phenotyping or phenotypic screening involves the comparison of wild-type control mice with their mutant or transgenic littermates. In our study, we explored
the extent to which standardized phenotyping will succeed in detecting biologically relevant phenotypic differences in mice
generated and provided by different collaborators. We analyzed quantitative metabolic data (body mass, energy intake, and
energy metabolized) collected at the GMC under the current workflow, and used them for statistical power considerations. Our
results demonstrate that there is substantial variability in these parameters among lines of wild-type C57BL/6 (B6) mice from
different sources. Given this variable background noise in mice that serve as controls, subtle phenotypes in mutant or transgenic
littermates may be overlooked. Furthermore, a phenotype observed in one cohort of a mutant line may not be reproducible (to
the same extent) in mice coming from a different environment or supplier. In the light of these constraints, we encourage
researchers to incorporate information on intrastrain variability into future study planning, or to perform advanced hierarchical
analyses. Both will ultimately improve the detectability of novel phenotypes by phenotypic screening.
Carola W. Meyer and Ralf Elvert contributed equally to this work. 相似文献
985.
986.
Further evidence of nuclear reactions in the Pd/D lattice: emission of charged particles 总被引:1,自引:1,他引:0
Almost two decades ago, Fleischmann and Pons reported excess enthalpy generation in the negatively polarized Pd/D-D2O system, which they attributed to nuclear reactions. In the months and years that followed, other manifestations of nuclear
activities in this system were observed, viz. tritium and helium production and transmutation of elements. In this report,
we present additional evidence, namely, the emission of highly energetic charged particles emitted from the Pd/D electrode
when this system is placed in either an external electrostatic or magnetostatic field. The density of tracks registered by
a CR-39 detector was found to be of a magnitude that provides undisputable evidence of their nuclear origin. The experiments
were reproducible. A model based upon electron capture is proposed to explain the reaction products observed in the Pd/D-D2O system.
相似文献
Pamela A. Mosier-BossEmail: |
987.
Host selection and infection strategies of parasitoids often correlate with high parental investment and low numbers of progeny.
In this study, we investigate how additional internal mechanisms might shape brood size and fitness of the offspring. Emblemasoma auditrix is a parasitoid fly in which about 38 larvae hatch simultaneously in utero. After host location, a single larva is deposited
into the host, where it rapidly develops and pupates after about 5 days. The search for hosts can take several weeks, and
during that time, the larvae arrest their development and remain in the first larval instar. Nevertheless, the larvae increase
in weight within the uterus, and this growth correlates to a decrease in the number of larvae, although no larvae are deposited.
Thus, our data indicate a first case of prenatal cannibalism in an invertebrate with larvae feeding on each other within the
uterus of the adult. 相似文献
988.
Recruitment precision, i.e. the proportion of recruits that reach an advertised food source, is a crucial adaptation of social
bees to their environment. Studies with honeybees showed that recruitment precision is not a fixed feature, but it may be
enhanced by factors like experience and distance. However, little is known regarding the recruitment precision of stingless
bees. Hence, in this study, we examined the effects of experience and spatial distance on the precision of the food communication
system of the stingless bee Scaptotrigona mexicana. We conducted the experiments by training bees to a three-dimensional artificial patch at several distances from the colony.
We recorded the choices of individual recruited foragers, either being newcomers (foragers without experience with the advertised
food source) or experienced (foragers that had previously visited the feeder). We found that the average precision of newcomers
(95.6 ± 2.61%) was significantly higher than that of experienced bees (80.2 ± 1.12%). While this might seem counter-intuitive
on first sight, this “loss” of precision can be explained by the tendency of experienced recruits to explore nearby areas
to find new rewarding food sources after they had initially learned the exact location of the food source. Increasing the
distance from the colony had no significant effect on the precision of the foraging bees. Thus, our data show that experience,
but not the distance of the food source, affected the patch precision of S. mexicana foragers. 相似文献
989.
Objective
To examine parental decisions about vehicles driven by teenagers and parental knowledge of vehicle safety.Methods
About 300 parents were interviewed during spring 2006 in Minnesota, North Carolina, and Rhode Island while teenagers took their first on-road driving tests.Results
Fewer than half of parents surveyed said teenagers would be the primary drivers of the chosen vehicles. Parents most often cited safety, existing family vehicle, and reliability when explaining the choices for their teenagers’ vehicles. About half of the vehicles intended for teenagers were small/mini/sports cars, pickups, or SUVs — vehicles considered less safe for teenagers than midsize/large cars or minivans. A large majority of vehicles were 2001 models or earlier. Vehicles purchased in anticipation of adding a new driver to the family were more likely to be the sizes/types considered less safe than vehicles already owned. Few parents insisted on side airbags or electronic stability control, despite strong evidence of their safety benefits. Even when asked to identify ideal vehicles for their teenagers to drive, about half of parents identified less safe vehicle sizes/types. Most parents knew that midsize/large vehicles are safer than small vehicles, and at least half of parents said SUVs and pickups are not safe for teenage drivers, citing instability.Conclusions
The majority of parents understood some of the important criteria for choosing safe vehicles for their teenagers. However, parents actually selected many vehicles for teenagers that provide inferior crash protection.Impact on industry
Vehicle safety varies substantially by vehicle size, type, and safety features. Many teenagers are driving inferior vehicles in terms of crashworthiness and crash avoidance. 相似文献990.
PROBLEM: Age and gender are frequently controlled for in studies of driving performance, but the effects of time of day or circadian cycles on performance are often not considered. Previous research on time of day effects of simulated driving is contradictory and provides little guidance for understanding the impact of these variables on results. METHODS: Using driving simulator data from 79 subjects ages 18 to 65, this paper focuses on the impact of age, gender, and time of day on the simulated driving performance of subjects who self-selected the time of participation. RESULTS: Time of day effects were consistently evident for drivers' speed overall and across different simulated environments. Drivers in the late afternoon period consistently drove significantly slower than drivers in other time periods. Age and gender affected speed such that women and those participants 50 and older tended to drive more slowly. Time of day also had an effect on reaction time and on speed variability measures. Gender did not have significant effects on reaction time or variability measures, but age effects were present. SUMMARY: Taken together, the results suggest that time of day effects should be considered as part of simulated driving performance, and that interactions between time of day and other variables, notably age, should be controlled for as part of future research. IMPACT ON INDUSTRY: Implications of these findings on current efforts for older driver testing are discussed. 相似文献