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141.
142.
Margaret Kalcic Linda Prokopy Jane Frankenberger Indrajeet Chaubey 《Environmental management》2014,54(4):795-813
Watershed managers have largely embraced targeting of agricultural conservation as a way to manage strategically non-point source pollution from agricultural lands. However, while targeting of particular watersheds is not uncommon, targeting farms and fields within a specific watershed has lagged. In this work, we employed a qualitative approach, using farmer interviews in west-central Indiana to better understand their views on targeting. Interviews focused on adoption of conservation practices on farmers’ lands and identified their views on targeting, disproportionality, and monetary incentives. Results show consistent support for the targeting approach, despite dramatic differences in farmers’ views of land stewardship, in their views about disproportionality of water quality impacts, and in their trust in conservation programming. While the theoretical concept of targeting was palatable to all participants, many raised concerns about its practical implementation, pointing to the need for flexibility when applying targeting solutions and revealing misgivings about the government agencies that perform targeting. 相似文献
143.
This study examined rates of karyotype abnormalities in fetuses diagnosed by ultrasound as abnormal before 20 weeks' gestational age and which prompted a follow-up amniocentesis or chorionic villus sampling. Those diagnosed before 20 weeks were compared with those diagnosed at or after 20 weeks. A retrospective study identified ultrasonographically abnormal fetuses in whom karyotyping had been undertaken, 306 fetuses before 20 weeks' gestational age and 241 after. Isolated malformations before 20 weeks had, on average, an 18 per cent risk of karyotype abnormality, compared with 20 per cent later. Specific rates were calculated; for example, heart abnormality was associated with karyotype abnormality in 7 per cent of cases before 20 weeks and in 14 per cent later. Multiple malformations and karyotype abnormalities were found together in 28 per cent of fetuses prior to 20 weeks and in 33 per cent of the older fetuses. Specific associations included nuchal oedema and trisomy 21 in 21 per cent of fetuses before 20 weeks. No karyotype abnormalities were found in fetuses diagnosed with choroid plexus cysts. An overview of trisomies in Victoria, in 1991, showed that 50 per cent of trisomy 18, 42 per cent of trisomy 13, and 9·5 per cent of trisomy 21 cases were identified by ultrasound in women less than 37 years of age. Another 28·6 per cent of trisomy 21 fetuses were detected in women of advanced maternal age who underwent amniocentesis or chorionic villus sampling, making a total of 38·1 per cent of trisomy 21 that were detected prenatally. The importance of early karyotyping specifically relates to the ongoing management of the pregnancy if the chromosomes are normal, and facilitates decision-making regarding termination of pregnancy if the chromosomes are abnormal. 相似文献
144.
145.
Diana W. Bianchi M.D Jane E. Stewart Mary Frances Garber Gérard Lucotte Alan F. Flint 《黑龙江环境通报》1991,11(8):523-528
Maternal venous blood samples, obtained from six pregnant women, were used as a source of fetal nucleated erythrocytes (NRBC). Fetal cell enrichment was potentiated by flow sorting with the monoclonal antibodies Tf R, Leu-4, and Leu-M3. Single copy Y chromosomal DNA sequences were detected in samples obtained from two women at 11 and 12 weeks' gestation. Y DNA sequences were absent in a subsequent sample from one of these women at 19 weeks and in two other women at 16 and 20 weeks. All four women delivered males. Y DNA sequences were not detected in two women who delivered females. By combining these results with prior data on the detection of Y chromosomal DNA sequences in maternal blood from male-bearing pregnancies, a relationship between gestational age and feta-maternal transfer of NRBC is suggested. 相似文献
146.
Chen Wenjun Chen Jing M. Price David T. Cihlar Josef Liu Jane 《Mitigation and Adaptation Strategies for Global Change》2000,5(2):143-169
Using an Integrated TerrestrialEcosystem C-budget model (InTEC), we simulated thecarbon (C) offset potentials of four alternativeforest management strategies in Canada: afforestation,reforestation, nitrogen (N) fertilization, andsubstitution of fossil fuel with wood, under differentclimatic and disturbance scenarios. C offset potentialis defined as additional C uptake by forest ecosystemsor reduced fossil C emissions when a strategy isimplemented to the theoretical maximum possibleextent. The simulations provided the followingestimated gains from management: (1) Afforesting allthe estimated 7.2 Mha of marginal agricultural landand urban areas in 1999 would create an average Coffset potential of 8 Tg C y-1 during 1999–2100,at a cost of 3.4 Tg fossil C emission in 1999. (2)Prompt reforestation of all forest lands disturbed inthe previous year during 1999–2100 would produce anaverage C offset potential of 57 Tg C y-1 forthis period, at a cost of 1.33 Tg C y-1. (3)Application of N fertilization (at the low rate of 5kg N ha-1 y-1) to the 125 Mha ofsemi-mature forest during 1999–2100 would create anaverage C offset of 58 Tg C y-1 for this period,at a cost of 0.24 Tg C y-1. (4) Increasingforest harvesting by 20% above current average ratesduring 1999–2100, and using the extra wood products tosubstitute for fossil energy would reduce averageemissions by 11 Tg C y-1, at a cost of 0.54 TgC y-1. If implemented to the maximum extent, thecombined C offset potential of all four strategieswould be 2–7 times the GHG emission reductionsprojected for the National Action Plan for ClimateChange (NAPCC) initiatives during 2000–2020, and anorder of magnitude larger than the projected increasein C uptake by Canada's agricultural soils due toimproved agricultural practices during 2000–2010. 相似文献
147.
Discovery of the fuel additive methyl tert-butyl ether (MTBE) in groundwater, surface water, and stormwater has prompted studies of its sources, transport and fate. More limited data, however, is available on the extent of contamination of coastal waters, as well as the persistence of MTBE in the marine environment. We apply here the combination of solid phase microextraction and gas chromatography-mass spectrometry to the detection of sub-to-low microgram/l concentrations of MTBE in seawater samples. Analysis of samples collected at the Marina del Rey harbor, a shallow recreational harbor near Los Angeles, CA, show MTBE contamination in the low microgram/l level. MTBE measurements were made at different depths, from the surface to the bottom, at five sites within the harbor during months showing no measurable precipitation. The highest concentration of MTBE (18 microgram/l) was found at the boat launching ramp, and the lowest (0.2 microgram/l) near the harbor entrance, approximately 2.3 km from the ramp. The levels of MTBE measured, as well as their variation over the study period, are fully consistent with recreational boating as the primary source of contamination. No evidence for MTBE contamination from the adjacent stormwater control channel was noted. 相似文献
148.
A general model of resource scarcity is presented from which previous models can be derived as special cases. Previous models of scarcity are compared and contrasted, refining the concept of scarcity and leading to a resolution of current disputes over the appropriate measure of scarcity. An update of the original work done by Barnett and Morse is summarized, leading to reconsideration of their original conclusions. It is found that energy and forest products experienced increasing scarcity during the 1970s. 相似文献
149.
Evelyn Vingilis Zümrüt Yıldırım-Yenier Larissa Vingilis-Jaremko Christine Wickens Jane Seeley Judy Fleiter 《Traffic injury prevention》2017,18(6):606-615
Objective: Entry of terms reflective of extreme risky driving behaviors into the YouTube website yields millions of videos. The majority of the top 20 highly subscribed automotive YouTube websites are focused on high-performance vehicles, high speed, and often risky driving. Moreover, young men are the heaviest users of online video sharing sites, overall streaming more videos, and watching them longer than any other group. The purpose of this article is to review the literature on YouTube videos and risky driving.Methods: A systematic search was performed using the following specialized database sources—Scopus, PubMed, Web of Science, ERIC, and Google Scholar—for the years 2005–2015 for articles in the English language. Search words included “YouTube AND driving,” “YouTube AND speeding,” “YouTube AND racing.”Results: No published research was found on the content of risky driving videos or on the effects of these videos on viewers. This literature review presents the current state of our published knowledge on the topic, which includes a review of the effects of mass media on risky driving cognitions; attitudes and behavior; similarities and differences between mass and social media; information on the YouTube platform; psychological theories that could support YouTube's potential effects on driving behavior; and 2 examples of risky driving behaviors (“sidewalk skiing” and “ghost riding the whip”) suggestive of varying levels of modeling behavior in subsequent YouTube videos.Conclusions: Every month about 1 billion individuals are reported to view YouTube videos (ebizMBA Guide 2015) and young men are the heaviest users, overall streaming more YouTube videos and watching them longer than women and other age groups (Nielsen 2011). This group is also the most dangerous group in traffic, engaging in more per capita violations and experiencing more per capita injuries and fatalities (e.g., Parker et al. 1995; Reason et al. 1990; Transport Canada 2015; World Health Organization 2015). YouTube also contains many channels depicting risky driving videos. The time has come for the traffic safety community to begin exploring these relationships. 相似文献
150.
David?R.?TarpyEmail author David?C.?Gilley Thomas?D.?Seeley 《Behavioral ecology and sociobiology》2004,55(6):513-523
The extended phenotype of a social insect colony enables selection to act at both the individual level (within-colony selection) and the colony level (between-colony selection). Whether a particular trait persists over time depends on the relative within- and between-colony selection pressures. Queen replacement in honey bee colonies exemplifies how selection may act at these different levels in opposing directions. Normally, a honey bee colony has only one queen, but a colony rears many new queens during the process of colony reproduction. The replacement of the mother queen has two distinct phases: queen rearing, where many queens develop and emerge from their cells, and queen elimination, where most queens die in a series of fatal duels. Which queens are reared to adulthood and which queens ultimately survive the elimination process depends on the strength and direction of selection at both the individual and colony levels. If within-colony selection is predominant, then conflict is expected to occur among nestmates over which queens are produced. If between-colony selection is predominant, then cooperation is expected among nestmates. We review the current evidence for conflict and cooperation during queen replacement in honey bees during both the queen rearing and queen elimination phases. In particular, we examine whether workers of different subfamilies exhibit conflict by acting nepotistically toward queens before and after they have emerged from their cells, and whether workers exhibit cooperation by collectively producing queens of high reproductive quality. We conclude that although workers may weakly compete through nepotism during queen rearing, workers largely cooperate to raise queens of similar reproductive potential so that any queen is suitable to inherit the nest. Thus it appears that potential conflict over queen replacement in honey bees has not translated into actual conflict, suggesting that between-colony selection predominates during these important events in a colonys life cycle.Communicated by A. Cockburn 相似文献