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701.
702.
The purpose of this study was to validate the use of adenosine triphosphate (ATP) for evaluating hygiene intervention effectiveness in reducing viral dissemination in an office environment. The bacterial virus MS-2 was used to evaluate two scenarios, one where the hand of an individual was contaminated and another where a fomite was contaminated. MS-2 was selected as a model because its shape and size are similar to many human pathogenic viruses. Two separate experiments were conducted, one in which the entrance door push plate was inoculated and the other in which the hand of one selected employee was inoculated. In both scenarios, 54 selected surfaces in the office were tested to assess the dissemination of the virus within the office. Associated surface contamination was also measured employing an ATP meter. More than half of the tested hands and surfaces in the office were contaminated with MS-2 within 4 h. Next, an intervention was conducted, and each scenario was repeated. Half of the participating employees were provided hand sanitizer, facial tissues, and disinfecting wipes, and were instructed in their use. A significant (p < 0.05) reduction was observed in the number of surfaces contaminated with virus. This reduction in viral spread was evident from the results of both viral culture and the surface ATP measurements, although there was no direct correlation between ATP measurements with respect to viral concentration. Although ATP does not measure viruses, these results demonstrate that ATP measurements could be useful for evaluating the effectiveness of hygiene interventions aimed at preventing viral spread in the workplace.  相似文献   
703.
Sociality in mole rats has been suggested to have evolved as a response to the widely dispersed food resources and the limited burrowing opportunities that result from sporadic rainfall events. In the most arid regions, individual foraging efficiency is reduced, and energetic constraints increase. In this study, we investigate seasonal differences in burrow architecture of the social Cryptomys hottentotus hottentotus in a mesic region. We describe burrow geometry in response to seasonal weather conditions for two seasons (wet and dry). Interactions occurred between seasons and colony size for the size of the burrow systems, but not the shape of the burrow systems. The fractal dimension values of the burrow systems did not differ between seasons. Thus, the burrow complexity was dependent upon the number of mole rats present in the social group.  相似文献   
704.
Pathogens exert a strong selection pressure on organisms to evolve effective immune defences. In addition to individual immunity, social organisms can act cooperatively to produce collective defences. In many ant species, queens have the option to found a colony alone or in groups with other, often unrelated, conspecifics. These associations are transient, usually lasting only as long as each queen benefits from the presence of others. In fact, once the first workers emerge, queens fight to the death for dominance. One potential advantage of co-founding may be that queens benefit from collective disease defences, such as mutual grooming, that act against common soil pathogens. We test this hypothesis by exposing single and co-founding queens to a fungal parasite, in order to assess whether queens in co-founding associations have improved survival. Surprisingly, co-foundresses exposed to the entomopathogenic fungus Metarhizium did not engage in cooperative disease defences, and consequently, we find no direct benefit of multiple queens on survival. However, an indirect benefit was observed, with parasite-exposed queens producing more brood when they co-founded, than when they were alone. We suggest this is due to a trade-off between reproduction and immunity. Additionally, we report an extraordinary ability of the queens to tolerate an infection for long periods after parasite exposure. Our study suggests that there are no social immunity benefits for co-founding ant queens, but that in parasite-rich environments, the presence of additional queens may nevertheless improve the chances of colony founding success.  相似文献   
705.
A modified method of severe plastic deformation (SPD) entitled constrained groove pressing-cross route (CGP-CR) was introduced for imposing a high magnitude of equivalent strain of about 2.32 per pass on the sheet form samples. The major benefit of this improved route compared to previous common route was the more homogeneity of strain in the rolling (RD) and transverse (TD) directions of sheets. In this study, low carbon steel samples were used for examination of evolutions in microstructure and mechanical properties during SPD via CGP-CR process. Mechanical properties improvement were measured by tensile and macro hardness tests. The results indicate that CGP-CR process can effectively improve tensile strength; and also, yield stress and hardness of as-received low carbon steel samples were improved up to about 100% after two deformation passes. Also, high magnitude of inhomogeneity can be observed in hardness distribution through first pass of the process which diminishes in the subsequent passes. Microstructural evolutions during process were monitored by optical microscopy observations and X-ray diffraction analysis. The results demonstrate that initial ferritic microstructure with grain size of about 30 μm was refined to a 225 nm cell structure after two passes of CGP-CR process.  相似文献   
706.
We explored the possible future impacts of increased coastal flooding due to sea level rise and the potential adaptation responses of two urban, environmental justice communities in the metropolitan Boston area of Massachusetts. East Boston is predominantly a residential area with some industrial and commercial activities, particularly along the coastal fringe. Everett, a city to the north of Boston, has a diversified industrial and commercial base. While these two communities have similar socioeconomic characteristics, they differ substantially in the extent to which residents would be impacted by increased coastal flooding. In East Boston, a large portion of residents would be flooded, while in Everett, it is the commercial/industrial districts that are primarily vulnerable. Through a series of workshops with residents in each community, we found that the target populations do not have an adaptation perspective or knowledge of any resources that could assist them in this challenge. Furthermore, they do not feel included in the planning processes within their communities. However, a common incentive for both communities was an intense commitment to their communities and an eagerness to learn more and become actively engaged in decisions regarding climate change adaptation. The lessons that can be applied to other studies include 1) images are powerful tools in communicating concepts, 2) understanding existing cultural knowledge and values in adaptation planning is essential to the planning process and 3) engaging local residents at the beginning of the process can create important educational opportunities and develop trust and consensus that is necessary for moving from concept to implementation.  相似文献   
707.
Laser forming process is used in forming and bending of metallic and non-metallic sheets. Laser beam irradiation causes a localized temperature increase and a localized mechanical strength decrease. In this article, an external mechanical force is added to a laser beam irradiation, which is called external force-assisted laser forming process, to gain a 90-degree bending angle. Furthermore, Numerical simulation of the process is performed to achieve a good understanding of the process. Simulation results show that more than two-third of the final forming is due to the laser beam irradiation. Equivalent plastic strain values during laser forming and external force-assisted laser forming processes are compared. Results show that equivalent plastic strain in laser forming process increases in a step pattern, with increasing in scan pass numbers. This occurs because when the laser beam irradiates on the sheet surface, it reduces the yield strength of the sheet. Equivalent plastic strain in external force-assisted laser forming process has an oscillatory step nature. This attributes to simultaneous effects of strain hardening and thermal induced reduction of yield strength of the sheet. Simulations were in good accordance with experiments.  相似文献   
708.
A new modeling effort exploring the opportunities, constraints, and interactions between mitigation and adaptation at regional scale is utilizing stakeholder engagement in an innovative approach to guide model development and demonstration, including uncertainty characterization, to effectively inform regional decision making. This project, the integrated Regional Earth System Model (iRESM), employs structured stakeholder interactions and literature reviews to identify the most relevant adaptation and mitigation alternatives and decision criteria for each regional application of the framework. The information is used to identify important model capabilities and to provide a focus for numerical experiments. This paper presents the stakeholder research results from the first iRESM pilot region. The pilot region includes the Great Lakes Basin in the Midwest portion of the United States as well as other contiguous states. This geographic area (14 states in total) permits cohesive modeling of hydrologic systems while also providing strong gradients in climate, demography, land cover/land use, and energy supply and demand. The results from the stakeholder research indicate that, for this region, iRESM should prioritize addressing adaptation alternatives in the water resources, urban infrastructure, and agriculture sectors, including water conservation, expanded water quality monitoring, altered reservoir releases, lowered water intakes, urban infrastructure upgrades, increased electric power reserves in urban areas, and land use management/crop selection changes. For mitigation in this region, the stakeholder research implies that iRESM should focus on policies affecting the penetration of renewable energy technologies, and the costs and effectiveness of energy efficiency, bioenergy production, wind energy, and carbon capture and sequestration.  相似文献   
709.
INTRODUCTION: Although the LATCH System (Lower Anchors and Tethers for Children) holds the promise of simplifying the installation of a child restraint system (CRS) to the vehicle's seat, many drivers transporting young children have difficulties using this technology. This paper reports on an observation study of LATCH use and misuse. METHOD: Observations of approximately 1,000 children less than 5 years of age in CRSs, in the back seats of vehicles that were equipped with tether and lower anchors, in seven states. RESULTS: Tethers were used for 51% of the children when the forward-facing CRS had tether straps and the vehicle had tether anchors. Lower anchors were used for 58% of the children when the CRS had lower attachments and the vehicle had lower anchors. The most common tether and lower attachment misuses were loose tether straps (18% of cases) and loose lower attachment installation (30% of the cases), respectively. Vehicle safety belts were used in combination with lower attachments in 20% of all lower anchor installations. CONCLUSION: As more caregivers of young children drive vehicles equipped with LATCH, it will be important to promote the proper installation of CRSs using this technology. LATCH education messages must also emphasize that the lower anchors may not always be the safest choice for CRS attachment -- the safest attachment is the one that results in a tight fit and will be used correctly consistently.  相似文献   
710.
OBJECTIVE: Since the shoulders are rarely seriously injured in frontal or oblique collisions, they have been given low priority in the development of frontal impact crash test dummies. The shoulder complex geometry and its kinematics are of vital importance for the overall dummy kinematics. The shoulder complex also influences the risk of the safety belt slipping off the shoulder in oblique forward collisions. The first aim of this study was to develop a new 50th percentile male THOR shoulder design, while the second was to compare the new shoulder, mounted on a THOR NT dummy, with volunteer, THOR NT, and Hybrid III range of motion and stiffness data. The third aim was to test the repeatability of the new shoulder during dynamic testing and to see how the design behaves with respect to belt slippage in a 45 degrees far-side collision. METHODS: The new 50th percentile THOR shoulder design was developed with the aid of a shell model of the seated University of Michigan Transportation Research Institute (UMTRI) 50th percentile male with coordinates for joints and bony landmarks (Schneider et al., 1983). The new shoulder design has human-like bony landmarks for the acromion and coracoid processes. The clavicle curvature and length are also made similar to that of a male human, as is the range of motion in the anterior-posterior, superior-inferior, and medial-lateral directions. The new shoulder design was manufactured and tested under the same conditions that T?rnvall et al. (2005b) used to compare the shoulder range of motion for the volunteers, Hybrid III, and THOR Alpha. The new design was also tested in two dynamic test configurations: the first was a 0 degrees full-frontal test and the second was a 45 degrees far-side test. The dummy tests were conducted with an R-16 seat with a three-point belt, the Delta V was 27.0+/-0.5 km/h and the maximum peak acceleration was approximately 14.6+/-0.5 g for each test. RESULTS: A new shoulder design with geometry close to that of humans was developed to be retrofitted to the THOR NT dummy. The results showed that the range of motion for the new shoulder complex during static loading was larger by at least a factor of three, for the maximum load (200 N/arm), than that of either the Hybrid III or the THOR NT; this means it was more similar to the volunteers' range of motion. It was observed that the THOR NT with the new shoulder did not slide out of the shoulder belt during a far-side collision. The performance of the new shoulder was reasonably repeatable and stable during both the static tests and the sled tests. CONCLUSION: A new shoulder for the THOR NT has been designed and developed, and data from static range of motion tests and sled tests indicate that the new shoulder complex has the potential to function in a more human-like manner on the THOR dummy.  相似文献   
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