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251.
Natural steroidal estrogens are an environmental concern because low nanogram per liter concentrations in water can adversely affect aquatic vertebrate species by disrupting the normal function of their endocrine systems. There is a critical need to accurately measure estrogens in dairy wastes, a potential source of estrogens such as 17beta-estradiol, to assess the risk of estrogen contamination of agricultural drainage waters resulting from land application. Commercially available enzyme immunoassay (EIA) kits have been used for measuring 17beta-estradiol in livestock manure, but it is not known if different EIAs provide similar results. We compared three EIAs by measuring 17beta-estradiol in two samples of flushed dairy manure wastewater (FDMW). The measured concentrations of 17beta-estradiol in FDMW differed according to the immunoassay used. The differences were attributed to a matrix interference associated with coextracted humic substances. Future research should develop methods that enable routine measurement of 17beta-estradiol in livestock wastes by more conclusive analytical techniques such as gas chromatography-mass spectrometry.  相似文献   
252.
253.
Anencephaly in twin B was accompanied by elevated amniotic fluid alpha-fetoprotein (AFP) and a positive acetylcholinesterase (AChE) band on gel electrophoresis in both twin sacs, although twin A was normal. AChE results did not help distinguish the false positive AFP in this set of twins, implying that AChE may diffuse transamniotically as has been previously postulated for AFP. In light of the low concordance rate for neural tube defects in twins, patient counselling in this situation must include the information that AFP and AChE may be falsely elevated in normal twin when the other twin has a neural tube defect.  相似文献   
254.
Summary This paper reports on 5 years of observatiors of individually marked saddle-backed tamarins (Saguinus fuscicollis, Callitrichidae). Although callitrichids have long been presumed to have a monogamous social system, this study shows that the breeding structure of saddle-back tamarin groups is highly variable. Groups most commonly include two or more adult males and a single reproductive female, but occasionally contain only a single pair of adults, or less often, two reproductively active females and one or more males. Data on group compositions, group formations, intergroup movements and copulations show that the social and mating systems of this species are more flexible than those of any other non-human primate yet studied. Infants (usually twins) were cared for by all group members. There were two classes of helpers: young, nonreproductive individuals who helped to care for full or half siblings, and cooperatively polyandrous males who cared for infants whom they may have fathered. The observations suggest that non-reproductive helpers may benefit from their helping behavior through a combination of inclusive fitness gains, reciprocal altruism, and the value of gaining experience at parental care.  相似文献   
255.
The evaluation of microbial responses to three in situ source removal remedial technologies—permanganate‐based in situ chemical oxidation (ISCO), six‐phase heating (SPH), and steam injection (SI)—was performed at Cape Canaveral Air Station in Florida. The investigation stemmed from concerns that treatment processes could have a variety of effects on the indigenous biological activity, including reduced biodegradation rates and a long‐term disruption of community structure with respect to the stimulation of TCE (trichloroethylene) degraders. The investigation focused on the quantity of phospholipid fatty acids (PLFAs) and its distribution to determine the immediate effect of each remedial technology on microbial abundance and community structure, and to establish how rapidly the microbial communities recovered. Comprehensive spatial and temporal PLFA screening data suggested that the technology applications did not significantly alter the site's microbial community structure. The ISCO was the only technology found to stimulate microbial abundance; however, the biomass returned to predemonstration values shortly after treatment ended. In general, no significant change in the microbial community composition was observed in the SPH or SI treatment areas, and even small changes returned to near initial conditions after the demonstrations. © 2004 Wiley Periodicals, Inc.  相似文献   
256.
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   
257.
Environmental auditing evolved as a means of providing assurance to top management that its health, safety, and environmental responsibilities were being adequately discharged and that no significant noncompliances existed. The author takes an in-depth look at the HSE audit program developed at Allied-Signal to permit continuous improvement of environmental management systems.  相似文献   
258.
All major journalism ethical codes explicitly state that journalists should protect editorial copy from undue influence by outside sources. However, much of the previous research on agricultural information has concentrated on what information various media communicate (gatekeeping studies) or communication's role in increasing innovation adoption (diffusion studies). Few studies have concentrated specifically on organizational and structural constraints that might adversely affect agricultural journalists' ethical standards; those that have, focus largely on farm magazines. A study of newspaper reporters who cover agricultural news found that the most pressing ethical concern is the effect of advertiser (agri-business) pressure on editorial copy, and that their concerns in general parallel those of farm magazine writers and editors. The majority reported being in situations in which they might be exposed to advertiser pressure, including pressures to change or withhold editorial copy. Large minorities suggested that advertising pressures affect the overall environment in which agricultural journalists work, and more than one in ten said they allow advertiser pressures to influence editorial decisions. The newspaper reporters who cover agricultural beats showed slightly more resistance to advertiser pressure than did farm magazine editors in a parallel study.  相似文献   
259.
Records of Decision from 16 environmental cleanup sites on 11 different Air Force bases were evaluated to determine if cost plays a role in remedy selection. Cost percentile (the cost of the selected remedy compared to the ranges of costs in the alternatives considered) was evaluated against the variables of risk (current and future, carcinogenic and noncarcinogenic), location, and contaminated media at the sites. Despite a statutory preference for permanent (and usually more expensive) remedies, the study found that cost is a significant factor in remedy selection. Eighty percent of the selected remedies fell in the bottom two thirds of alternatives by cost. Current carcinogenic risk and cost percentile were moderately correlated, but no significant correlation was found between the percentile of the selected remedy and future risk at the site or the location of the site. There was a moderate correlation between the contaminated medium and the percentile. Decision makers at sites with contaminated groundwater were more likely to select a high-cost alternative than sites with other contaminated media.  相似文献   
260.
Summary From 1983 to 1986 we monitored 284 European starling (Sturnus vulgaris) nests in New Jersey for evidence of intraspecific brood parasitism and egg removal during the laying period. Egg removal occurred significantly more often at nests where intraspecific brood parasitism was detected (12 of 35 nests, 34%) than at unparasitized nests (23 of 249 nests, 9%). Brood parasitism (92% of parasitized nests) and egg removal (74% of nests with egg removal) were most common at nests where egg laying began in April of each year (i.e., early nests). Egg removal occurred at 26 (19%) and brood parasitism at 32 (23%) of 138 early nests. Both brood parasitism and egg removal were concentrated during the first four days in the laying period when brood parasitism is most likely to be successful and when host nests are most vulnerable to parasitism (Romagnano 1987). Both parasitism and removal usually involved a single egg at each nest. We detected brood parasitism and egg removal on the same day at five of 12 nests (42%) where both were observed. Because starlings do not remove foreign eggs from their nests once they begin laying (Stouffer et al. 1987) we hypothesize that parasite females sometimes removed host eggs while parasitizing nests.  相似文献   
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