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251.
Minimal transmission of zearalenone to milk of dairy cows   总被引:2,自引:0,他引:2  
Milk and plasma levels of zearalenone (ZEN), alpha-zearalenol (alpha-ZEL), beta-zearalenol (beta-ZEL) and conjugated metabolites were determined after feeding lactating cows with ZEN. In those instances where ZEN and alpha- and beta-ZEL were detected in milk or plasma, they occurred only as conjugates hydrolysable by treatment with a mixture of beta-glucuronidase and aryl sulfatase. With studies where 50 or 165 mg was fed daily to three cows for 21 day periods, neither dosage showed the presence of ZEN or metabolites in either milk or plasma (detection limits: milk, 0.5 ng/ml, ZEN, alpha-ZEL; 1.5 ng/ml, beta-ZEL; plasma, 2-3 times higher). A dose of 544.5 mg zearalenone per day given to a single cow for 21 days yielded maximum concentrations of only 2.5 ng ZEN/ml and 3.0 ng alpha-ZEL/ml in the milk. In plasma, up to 3 ng ZEN/ml could be detected during the initial 4 days of treatment. At a dose of 1.8 g of zearalenone given over a one day feeding period, maximum milk levels of 4.0 ng ZEN/ml, 1.5 ng alpha-ZEL/ml, and 4.1 ng beta-ZEL/ml were observed during the initial 2 days; corresponding maximum levels after a one day dose of 6.0 g zearalenone were 6.1, 4.0 and 6.6 ng/ml milk on days 2-3. In plasma, peak ZEN concentrations (9 and 13 ng/ml at the lower and higher one-day doses, respectively) occurred 12 hr after initial dosing, and declined to negligible levels by days 5-7. Neither alpha- nor beta-ZEL were detected in plasma. Since measurable levels required very high oral doses of ZEN, milk would not normally pose a human health hazard as a result of feeding rations containing ZEN to lactating dairy cows.  相似文献   
252.
Stable carbon isotopic analysis, in combination with compositional analysis, was used to evaluate the performance of an iron permeable reactive barrier (PRB) for the remediation of ground water contaminated with trichloroethene (TCE) at Spill Site 7 (SS7), F.E. Warren Air Force Base, Wyoming. Compositional data indicated that although the PRB appeared to be reducing TCE to concentrations below treatment goals within and immediately downgradient of the PRB, concentrations remained higher than expected at wells further downgradient (i.e. >9 m) of the PRB. At two wells downgradient of the PRB, TCE concentrations were comparable to upgradient values, and delta13C values of TCE at these wells were not significantly different than upgradient values. Since the process of sorption/desorption does not significantly fractionate carbon isotope values, this suggests that the TCE observed at these wells is desorbing from local aquifer materials and was present before the PRB was installed. In contrast, three other downgradient wells show significantly more enriched delta13C values compared to the upgradient mean. In addition, delta13C values for the degradation products of TCE, cis-dichloroethene and vinyl chloride, show fractionation patterns expected for the products of the reductive dechlorination of TCE. Since concentrations of both TCE and degradation products drop to below detection limit in wells within the PRB and directly below it, these downgradient chlorinated hydrocarbon concentrations are attributed to desorption from local aquifer material. The carbon isotope values indicate that this dissolved contaminant is subject to local degradation, likely due to in situ microbial activity.  相似文献   
253.
Summary The benefits to partners of monogamous pairs of maintaining continual spatial proximity in the non-breeding season were studied in Bewick's swans wintering in Norfolk, UK.When separated from their mates, females were less successful in aggressive encounters, were threatened more frequently and spent less time feeding than when close to them. Males also suffered reduced success in encounters and a higher frequency of threats by other flock members, though the effect was less pronounced than for females. This sex difference in effect of separation may be associated with the greater weight of males and the fact that success in encounters is related to weight.Partners appeared to assist each other by joining in aggressive encounters, as well as by inhibiting other birds from threatening their mates. However, the precise manner in which the female assisted the male is still obscure, since the highest intensity aggressive encounters — physical fights — involved only male partners. It is suggested that the male may fight harder in his mate's presence.Proximity of partners varied with situation and between different pairs. Partners maintained greater proximity in dense flocks than in dispersed flocks and showed a tendency to stay closer when feeding on winter wheat than on waste potatoes. Partners where the male was high-ranking spent more time together than those where the male was low-ranking.  相似文献   
254.
Inclusive fitness theory predicts that cost of tolerant behaviour during competitive interactions is lower for relatives than for nonrelatives. Many studies have examined the effect of relatedness on behaviour within social groups. In contrast, kin selection acting among groups has received less attention. The genetic structure of African lion (Panthera leo) populations creates a strong possibility that kin selection among groups modifies behaviour during group conflicts. We used playback experiments and genetic data to investigate the importance of relatedness during simulated territorial disputes in lions. However, we found no effect of relatedness on territorial behaviour. Degree of relatedness did not affect the decision to approach simulated intrusions, nor did it affect the behaviour during approaches. The decision to approach was instead affected by position within the territory and consecutive playback number (a measure of habituation). For playbacks that did elicit an approach, the speed of response was not detectably affected by relatedness, but was affected by odds (the ratio of residents to intruders), number of intruders, number of bouts, presence of cubs, position within the territory, temperature and playback number. Although responses were unaffected by relatedness, it remains possible that other aspects of behaviour during natural encounters among prides are affected by kin selection.Communicated by L. Sterck  相似文献   
255.
A method is developed to estimate the stress at the surface in a portable wind tunnel for wind erosion studies. The boundary layer height and the pressure gradient are used in a simple expression from the Kármán Integral Momentum Equation. Values of friction velocity u * are within 10% of experimental values obtained through correlation techniques, including measurements of differential pressures with the Murdoch Turbulence Probe MTP and the X-wire, hot-wire anemometer XWA. Wind velocity and stress profiles reveal logarithmic trends and a constant stress layer near the surface in the DAWA portable wind tunnel. Realignment of the statistics with the mean wind is essential.  相似文献   
256.
Objective: Studies of alcohol-related harm (violence, injury, illness) suggest that the most significant risk factors are the amount of alcohol consumed and whether obviously intoxicated patrons continue to be served. This study's objective was to investigate the effects of a responsible beverage service (RBS)/enhanced alcohol enforcement intervention on bars, bar patrons, and impaired driving.

Method: Two communities—Monroe County, New York, and Cleveland, Ohio—participated in a demonstration program and evaluation. The intervention applied RBS training, targeted enforcement, and corrective actions by law enforcement to a random sample of 10 identified problem bars in each community compared to 10 matched nonintervention problem bars. Data were collected over 3 waves on bar serving practices, bar patron intoxication, drinking and driving, and other alcohol-related harm from intervention and control bars and treatment and comparison communities.

Results: In Monroe County, New York, of the 14 outcome measures analyzed, 7 measures showed statistically significant differences from pre- to postintervention. Six of those measures indicated changes in the desired or positive direction and 2 measures were in the undesired or negative direction. Of note in the positive direction, the percentage of intervention bar patrons who were intoxicated decreased from 44 to 27% and the average blood alcohol concentration of patrons decreased from 0.097 to 0.059 g/dL pre- to postintervention. In Cleveland, Ohio, 6 of the 14 measures showed statistically significant changes pre- to postintervention with 6 in the positive direction and 4 in the negative direction. Of note, the percentage of pseudo-intoxicated patrons denied service in intervention bars increased from 6 to 29%.

Conclusions: Of the 14 outcome measures that were analyzed in each community, most indicated positive changes associated with the intervention, but others showed negative associations. About half of the measures showed no significance, the sample sizes were too small, or the data were unavailable. Therefore, at best, the results of these demonstration programs were mixed. There were, however, some positive indications from the intervention. It appears that when bar managers and owners are aware of the program and its enforcement and when servers are properly trained in RBS, fewer patrons may become intoxicated and greater efforts may be made to deny service to obviously intoxicated patrons. Given that about half of arrested impaired drivers had their last drink at a licensed establishment, widespread implementation of this strategy has the potential to help reduce impaired driving.  相似文献   

257.
The provision of green and open space in the face of wider development pressure is a key urban challenge. Despite this, few studies have critically investigated the quality of life implications of such provision. This paper focuses on perceptions of built environment factors and their influence on neighbourhood quality of life. Data are drawn from a household survey questionnaire completed by 483 residents living in three neighbourhoods in Dublin, Ireland – an inner city neighbourhood, a suburb and a peri-urban settlement. Positive perceptions of green and open space were identified as important predictors of high levels of neighbourhood satisfaction, surpassed only by dwelling characteristics. This suggests that development strategies which fail to provide for properly planned green and open spaces may be detrimental to neighbourhood quality of life. Furthermore, the results suggest a need for design solutions which consider neighbourhood typology in achieving improved neighbourhood quality of life.  相似文献   
258.
Objective: The objective of this study was to leverage a state health department's operational data to allocate in-kind resources (children's car seats) to counties, with the proposition that need-based allocation could ultimately improve public health outcomes.

Methods: This study used a retrospective analysis of administrative data on car seats distributed to counties statewide by the Georgia Department of Public Health and development of a need-based allocation tool (presented as interactive supplemental digital content, adaptable to other types of in-kind public health resources) that relies on current county-level injury and sociodemographic data.

Results: Car seat allocation using public health data and a need-based formula resulted in substantially different recommended allocations to individual counties compared to historic distribution.

Conclusions: Results indicate that making an in-kind public health resource like car seats universally available results in a less equitable distribution of that resource compared to deliberate allocation according to public health need. Public health agencies can use local data to allocate in-kind resources consistent with health objectives; that is, in a manner offering the greatest potential health impact. Future analysis can determine whether the change to a more equitable allocation of resources is also more efficient, resulting in measurably improved public health outcomes.  相似文献   

259.
Aim: The aim of this study was to synthesize published qualitative studies to identify older adults' preferences for communication about driving with health care providers.

Background: Health care providers play a key role in addressing driving safety and driving retirement with older adults, but conversations about driving can be difficult. Guides exist for family members and providers, but to date less is known about the types of communication and messages older drivers want from their health care providers.

Design: A qualitative metasynthesis of studies published on or before October 10, 2014, in databases (PubMed, CINAHL, PsycINFO, and Web of Science) and grey literature was performed.

Review Methods: Twenty-two published studies representing 518 older adult drivers met the following inclusion criteria: the study (1) was about driving; (2) involved older drivers; (3) was qualitative (rather than quantitative or mixed methods); and (4) contained information on older drivers' perspectives about communication with health care providers.

Results: We identified 5 major themes regarding older adults' communication preferences: (1) driving discussions are emotionally charged; (2) context matters; (3) providers are trusted and viewed as authority figures; (4) communication should occur over a period of time rather than suddenly; and (5) older adults desire agency in the decision to stop driving.

Conclusion: Various stakeholders involved in older driver safety should consider older drivers' perspectives regarding discussions about driving. Health care providers can respect and empower older drivers—and support their family members—through tactful communication about driving safety and mobility transitions during the life course.  相似文献   

260.
Occupational back stress among manual workers in South Africa is now a cause of governmental concern. Yet no data on the back strength of the South African workforce have been published. This study represents a first step in reporting the trunk strength of Xhosa workers in South Africa, in absolute and size-relative terms. Thirty-five male manual workers were tested isometrically while making maximal extension and flexion efforts at 0°, 23°, 46°, 69°, and 92° of stoop. The results show nonlinearity of the extensor-to-flexor (E/F) ratio of the trunk musculature. The E/F ratio increases in deep stoop because of a drop in flexor torques. The data suggest that predictions of flexor from extensor torques or vice versa can confidently be made so long as testing is done away from the fully flexed position. Significant differences between morphologically gracile and robust workers in this sample are discussed. The study has implications for occupational rehabilitation and for prophylaxis, for whereas muscular strength alone may not protect the spine from occupational injury, muscular weakness certainly predisposes it.  相似文献   
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