A technique for sampling pure fetal blood in twin pregnancies using a single uterine entry with a fetoscope is described. The fetoscope was inserted into one sac and after blood had been obtained from that, twin, the fetus in the other sac was sampled by trans-septal passage of the blood-sampling needle. This was done in six out of seven patients, the first in the series having two separate insertions of the fetoscope, one into each sac. Pure fetal blood was taken from all 14 fetuses, either from the placental insertion of the umbilical cord or the umbilicus, and the volume of the samples ranged from 200 μl to 1200 μl. In six patients the fetuses were at risk of β-thalassaemia and in one of haemophilia A. Some observations are made relating zygosity to the ultrasonic and fetoscopic appearance of the septum between the sacs. 相似文献
In understanding the safety climate or culture of a workplace, the perceptions and attitudes of the workforce are important factors in assessing safety needs. Safety solutions may fail if they do not take into account these prevailing attitudes and perceptions. Also, changes in attitudes and perceptions about safety are often likely outcomes of safety interventions. The aim of this study was to develop a measure of perception and attitudes about safety as an indicator of safety culture for use with working populations. After reviewing the structure and content of a number of older, related measures of safety attitudes, a 67-item questionnaire was developed. The questionnaire was distributed in a self-administered form to 1560 workers in a wide variety of types of jobs and 660 questionnaires were returned from 7 workplaces with a response rate of 42%. Items were evaluated by Cronbach alpha which showed that the item set shared considerable common variance. Scale development was approached in two ways. First items which were highly skewed were removed, resulting in removal of around half of the items, with very little loss in alpha. The remaining items were then subjected to factor analysis which revealed five factors; personal motivation for safe behaviour, positive safety practice, risk justification, fatalism and optimism. This factor structure showed acceptable psychometric properties. Second, in an effort to produce a unidimensional scale with a small, but representative set of items, additional items were removed which had high correlation with other items. This resulted in loss of around half of the remaining items. The short scale contained 17 items with again overall acceptable psychometric properties. The most striking finding in the development of this questionnaire was that there was little variation between respondents on a very large proportion of the questions originally selected. Clearly there are well-known beliefs about safety in the working community which need to be understood in order to progress the concept of safety culture. 相似文献
In much of the San Joaquin Valley, California, USA, inadequate drainage of applied irrigation water and accumulating salts
in the soil have necessitated the installation of subsurface tile drainage systems to preserve crop productivity. At present,
these subsurface drainage waters are disposed of by means of evaporation ponds or discharges into the San Joaquin River. Unfortunately,
most of these agricultural drainage waters contain high concentrations of salts and naturally occurring trace elements, such
as selenium, and recent evidence indicates that substantial numbers of waterbirds are exposed to contamination by selenium
in the evaporation ponds. In order to avoid, minimize, or mitigate the adverse impacts on wildlife using the ponds, alternative
pond management methods must be identified and evaluated for implementation. A number of methods have the potential to be
cost-effective in significantly reducing the contamination hazard to birds using agricultural evaporation ponds. Twenty general
methods were evaluated in this study, and four methods are recommended for implementation: remove levee vegetation, remove
windbreaks, deepen the ponds, and haze birds. A number of other methods are recommended for further consideration because
they appear to have good prospects for reducing the contamination hazard: steepen interior levee slopes, apply herbicides
and insecticides, place netting on pond shorelines, and provide freshwater habitat adjacent to evaporation ponds. It may be
necessary to use a combination of methods to effectively control selenium contamination of aquatic birds because it is unlikely
that a single affordable pond management method will be able to entirely eliminate the contamination hazard. 相似文献
Through the Direct/Delayed Response Project (DDRP), the United States Environmental Protection Agency is attempting to assess the risk to surface waters from acidic deposition in three regions of the eastern United States: the Northeast Region, the Southern Blue Ridge Province, and the Mid-Appalachian Region. The central policy question being addressed by the DDRP is: Within the regions of concern, how many surface water systems (lakes, streams) will become acidic due to current or altered levels of acidic sulfur deposition, and on what time scales? The approach taken by the DDRP is to select a statistically representative set of watersheds in each region of concern and to project the future response of each watershed to various assumed levels of acidic deposition. The probability structure will then be used to extrapolate the watershed-specific results to each region. The data will be used also for statistical investigation of hypothesized relationships between current surface water chemistry and watershed characteristics. Because the needed terrestrial data base was not available, regional watershed surveys were conducted to meet the specific data needs of the DDRP. Maps (1∶24,000) of soils, vegetation, land use, depth to bedrock, and bedrock geology were made for each watershed. The soils were grouped into sampling classes based on their hypothesized response to acidic deposition. Randomized sampling of these classes provided regional means and variances of soil properties that can be applied to individual watersheds. Because of DDRP's need for consistency within and among regions, unique quality control/quality assurance activities were developed and implemented. After verification and validation, the DDRP data base will be made publicly available. This will be a unique and useful resource for others investigating watershed relationships on a regional scale. The results of these surveys and the conclusions of the DDRP will be presented in several future papers. The current paper gives an overview of the context, rationale, logistical considerations, and implementation of these surveys, with special emphasis on the field activities of watershed mapping and soil sampling. This discussion should be useful to those planning, implementing, and managing survey activities in support of regional assessments of other environmental concerns, who are likely to face similar choices and constraints. 相似文献
It seems like a simple enough exercise. After the opening meeting, the audit team embarks on an orientation tour to familiarize itself with the layout of the facility. A simple ?walk about”? as the Australians would say. If the site is bigenough, maybe the team climbs into a vehicle for the tour. Although the orientation tour typically represents only one hour, this hour is as important as any other for the audit team. This article discusses ten steps audit teams can take to maximize the effectiveness of the tour. The ten steps came about as a result of observing audit teams during many training audits and seeing persistent problems arise. 相似文献
In 1996, the International Standards Organization (ISO) completed work on an environmental management system (EMS) standard: ISO 14001. The standard involves only five required elements, spans less than five pages, and upon initial review, appears relatively uncomplicated. As well, many of the ISO 14001 requirements may already be present in an organization's existing EMS. Nevertheless, the new standard presents a number of challenges to industry implementation. Whether an organization aims to start from scratch in developing an EMS under ISO 14001 or modify its existing EMS to meet the ISO challenge, implementation requires careful planning and analysis. This article provides a summary of the planning required to implement ISO 14001 at the facility level, including the initial planning effort and the identification of significant environmental impacts, objectives, and targets. The aim will be to eliminate some of the “hype” associated with ISO and provide some practical “how to” guidance for implementing the standard. The discussion begins with an overview of the initial planning effort and then turns to key planning requirements. 相似文献
Objective: Although advanced restraint systems, such as seat belt pretensioners and load limiters, can provide improved occupant protection in crashes, such technologies are currently not utilized in military vehicles. The design and use of military vehicles presents unique challenges to occupant safety—including differences in compartment geometry and occupant clothing and gear—that make direct application of optimal civilian restraint systems to military vehicles inappropriate. For military vehicle environments, finite element (FE) modeling can be used to assess various configurations of restraint systems and determine the optimal configuration that minimizes injury risk to the occupant. The models must, however, be validated against physical tests before implementation. The objective of this study was therefore to provide the data necessary for FE model validation by conducting sled tests using anthropomorphic test devices (ATDs). A secondary objective of this test series was to examine the influence of occupant body size (5th percentile female, 50th percentile male, and 95th percentile male), military gear (helmet/vest/tactical assault panels), seat belt type (3-point and 5-point), and advanced seat belt technologies (pretensioner and load limiter) on occupant kinematics and injury risk in frontal crashes.
Methods: In total, 20 frontal sled tests were conducted using a custom sled buck that was reconfigurable to represent both the driver and passenger compartments of a light tactical military vehicle. Tests were performed at a delta-V of 30 mph and a peak acceleration of 25 g. The sled tests used the Hybrid III 5th percentile female, 50th percentile male, and 95th percentile male ATDs outfitted with standard combat boots and advanced combat helmets. In some tests, the ATDs were outfitted with additional military gear, which included an improved outer tactical vest (IOTV), IOTV and squad automatic weapon (SAW) gunner with a tactical assault panel (TAP), or IOTV and rifleman with TAP. ATD kinematics and injury outcomes were determined for each test.
Results: Maximum excursions were generally greater in the 95th percentile male compared to the 50th percentile male ATD and in ATDs wearing TAP compared to ATDs without TAP. Pretensioners and load limiters were effective in decreasing excursions and injury measures, even when the ATD was outfitted in military gear.
Conclusions: ATD injury response and kinematics are influenced by the size of the ATD, military gear, and restraint system. This study has provided important data for validating FE models of military occupants, which can be used for design optimization of military vehicle restraint systems. 相似文献
PM2.5 is one of the most important aspects of environmental health. This air pollutant is breathable and it is implicated in several chronic adverse health effects such as the decrease of respiratory functionality and cancer. Several in vitro bioassays are able to predict the mutagenic/carcinogenic activity of the environmental pollutants and mixtures of them. In this study PM2.5 air pollution was daily monitored in three cities located in the Northern part of Italy and the mutagenic properties of the PM2.5 organic extracts were also assessed. Samplings lasted 14 months and cover the period of the Winter Olympic Games of "Torino 2006". In this work, the levels of PM2.5, its mutagenic properties (detected with Salmonella typhimurium assay), the role of the Olympic Games as environmental factor and some meteorological data are discussed. The mean concentration of PM2.5 measured in Torino was 45.4 (+/-30.6) microg/m(3), in Pavia 37.6 (+/-25.6) microg/m(3), in Verona 43.1 (+/-28.5) microg/m(3). Findings of the monthly pool bioassay were in Torino 107 (+/-104) net revertans/m(3), in Pavia 108 (+/-89) net revertans/m(3), in Verona 128 (+/-109) net revertans/m(3). The Olympic Games period data show that PM2.5 pollution and its load of mutagenic potential are different and partially independent phenomena. The Olympic Games had not a great impact on the PM2.5 pollution. The exclusive PM2.5 gravimetric analysis shows a potential human risk if compared with the latest international guide values but it does not describe exhaustively the human health risk associated to the presence of this particular air pollutant. Moreover, the chemical and biological activity qualification of the PM organic extracts as a whole, can instead improve the knowledge. 相似文献
The southern Yucatán contains the largest expanse of seasonal tropical forests remaining in Mexico, forming an ecocline between the drier north of the peninsula and the humid Petén, Guatemala. The Calakmul Biosphere Reserve resides in the center of this region as part of the Mesoamerican Biological Corridor. The reserve's functions are examined in regard to land changes throughout the region, generated over the last 40 years by increasing settlement and the expansion and intensification of agriculture. These changes are documented from 1987/1988 to 2000, and their implications regarding the capacity of the reserve to protect the ecocline, forest habitats, and butterfly diversity are addressed. The results indicate that the current landscape matrix serves the biotic diversity of the reserve, with several looming caveats involving the loss of humid forests and the interruption of biota flow across the ecocline, and the amount and proximity of older forest patches beyond the reserve. The highly dynamic land cover changes underway in this economic frontier warrant an adaptive management approach that monitors the major changes underway in mature forest types, while the paucity of systematic ecological and environment-development studies is rectified in order to inform policy and practice. 相似文献