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排序方式: 共有375条查询结果,搜索用时 31 毫秒
61.
Amy B. Levine MD Keith A. Eddleman Usha Chitkara Judith P. Willner Robert J. Vosatka Richard L. Berkowitz 《黑龙江环境通报》1991,11(2):111-115
Two cases of severe polyhydramnios are presented in which the unsuspected diagnosis of myotonic dystrophy was made in the patient and the fetus. 相似文献
62.
Maternal serum alpha-fetoprotein (MSAFP) was determined in patients 33 to 40 weeks pregnant, and the results were analysed with consideration of the presence and quality of hypertensive disease that complicated many of the pregnancies. Patients with incompletely controlled hypertension had significantly higher MSAFP levels than control patients with pregnancies uncomplicated by any risk factor. MSAFP elevation was greatest in pre-eclampsia (301·6 ± 147·6 kU/L, n = 35) > chronic hypertension with superimposed pre-eclampsia (240·4±74.7 kU/L, n = 30) > chronic hypertension (204·1± 105·3 kU/L, n=141). Each was significantly increased (P< 0·0001) over control pregnant patients' levels (104·3 ± 38·8, n= 187). At each gestational week from 33 weeks to term, MSAFP of combined hypertensive women was significantly greater than corresponding control levels (P< 0·003 to < 0·000l). The magnitude and time of onset of MSAFP increase may indicate severe fetal distress. 相似文献
63.
McDonald JD Zielinska B Fujita EM Sagebiel JC Chow JC Watson JG 《Journal of the Air & Waste Management Association (1995)》2003,53(2):185-194
Emission rates for fine particle (<2.5 microm) mass (PM2.5), carbon (organic/elemental), inorganic ions (SO4(2-), NO3-, NH4+), elements (primarily metals), and speciated organic compounds are reported for charbroiling hamburger, steak, and chicken. The PM2.5 rates for charbroiling meats ranged from 4.4 to 11.6 g/kg of uncooked meat in this study. No mass-emission rates are available from grilling, but the speciated organic data are available for these samples. Emission rates varied by type of appliance, meat, meat-fat content, and cooking conditions. High-fat hamburger cooked on an underfired charbroiler emitted the highest amount of PM2.5. The emissions were almost exclusively composed of organic carbon, with small amounts of elements and inorganic ions. Water-soluble K+ and Cl-, which are used as indicators of wood smoke in source apportionment studies, were also present in meat-cooking emissions. The speciated organic compounds that were measured include polycyclic aromatic hydrocarbons (PAHs), cholesterol, and the long-chain gamma-lactones. Charbroiling emissions yielded an average of approximately 3-5 times more PAHs, approximately 20 times more cholesterol, and approximately 10 times more lactones than grilling. These data were utilized in the ambient source apportionment analysis for the 1997 Northern Front Range Air Quality Study source apportionment. 相似文献
64.
Monitoring of particulate matter outdoors 总被引:6,自引:0,他引:6
65.
66.
67.
Chow JC Watson JG Louie PK Chen LW Sin D 《Environmental pollution (Barking, Essex : 1987)》2005,137(2):334-344
Samples from Hong Kong, China, were analyzed for organic carbon (OC), elemental carbon (EC), and total carbon (TC) by three thermal protocols (low-temperature IMPROVE and high-temperature STN and NIOSH) and two optical monitoring methods: reflectance and transmittance. Good agreement (+/-10%) for TC among the three protocols was observed for sample loadings of 1-55 microg m(-3). The two protocols using a reflectance pyrolysis correction showed best agreement for EC, with <20% differences found for approximately 80% of the samples. Hong Kong has a large diesel fleet, and for some heavily loaded samples the light transmittance was too low for quantitative detection, resulting in large uncertainties in the OC/EC split based on transmittance. Hong Kong experienced OC levels similar to those at US sites, but has much higher EC concentrations. OC/EC ratios range from 2 to 5 at two US sites and from 0.2 to 1.2 at three Hong Kong sites. 相似文献
68.
Joyeeta Gupta Catrien Termeer Judith Klostermann Sander Meijerink Margo van den Brink Pieter Jong Sibout Nooteboom Emmy Bergsma 《Environmental Science & Policy》2010,13(6):459-471
Climate change potentially brings continuous and unpredictable changes in weather patterns. Consequently, it calls for institutions that promote the adaptive capacity of society and allow society to modify its institutions at a rate commensurate with the rate of environmental change. Institutions, traditionally conservative and reactive, will now have to support social actors to proactively respond through planned processes and deliberate steps, but also through cherishing and encouraging spontaneous and autonomous change, as well as allowing for institutional redesign. This paper addresses the question: How can the inherent characteristics of institutions to stimulate the capacity of society to adapt to climate change from local through to national level be assessed? On the basis of a literature review and several brainstorm sessions, this paper presents six dimensions: Variety, learning capacity, room for autonomous change, leadership, availability of resources and fair governance. These dimensions and their 22 criteria form the Adaptive Capacity Wheel. This wheel can help academics and social actors to assess if institutions stimulate the adaptive capacity of society to respond to climate change; and to focus on whether and how institutions need to be redesigned. This paper also briefly demonstrates the application of this Adaptive Capacity Wheel to different institutions. 相似文献
69.
Judith?MoralesEmail author Roxana?Torres Alberto?Velando 《Behavioral ecology and sociobiology》2012,66(1):135-143
In evolutionary biology, whether parents should enhance or reduce parental care according to mate ornamentation is a subject
of great debate. However, the evolution of female ornaments can shed light on this question. In theory, female ornamentation
should be traded off against fecundity and thus cannot be wholly informative to males without a direct indication of fecundity.
Hence, direct cues of offspring quality should affect the relationship between male investment and female ornamentation. Under
this hypothesis, we manipulated two direct cues of offspring quality (egg size and color) after first egg laying in the blue-footed
booby and registered male incubation patterns. In this species, foot color is a dynamic signal of current condition and in
females is traded off with egg size. We found that males spent more time incubating when paired with dull females but only
in nests with large eggs. Males also spent less time incubating small dull eggs. Results indicate that egg size, a direct
cue of reproductive value, affected the relationship between male effort and female ornamentation. Males may be willing to
help females that have invested in offspring at the expense of ornamentation, which suggests compensation when females are
in low condition. Another possibility is that males relax their effort when paired with highly ornamented and fecund females
because they have high parenting abilities. Our findings suggest that the information conveyed by female ornaments may depend
on direct cues of fecundity. Results also highlight that parental decisions are complex, modulated by a combination of information
sources. 相似文献
70.
Most plants attract multiple flower visitors that may vary widely in their effectiveness as pollinators. Floral evolution is expected to reflect interactions with the most important pollinators, but few studies have quantified the contribution of different pollinators to current selection on floral traits. To compare selection mediated by diurnal and nocturnal pollinators on floral display and spur length in the rewarding orchid Gymnadenia conopsea, we manipulated the environment by conducting supplemental hand-pollinations and selective pollinator exclusions in two populations in central Norway. In both populations, the exclusion of diurnal pollinators significantly reduced seed production compared to open pollination, whereas the exclusion of nocturnal pollinators did not. There was significant selection on traits expected to influence pollinator attraction and pollination efficiency in both the diurnal and nocturnal pollination treatment. The relative strength of selection among plants exposed to diurnal and nocturnal visitors varied among traits and populations, but the direction of selection was consistent. The results suggest that diurnal pollinators are more important than nocturnal pollinators for seed production in the study populations, but that both categories contribute to selection on floral morphology. The study illustrates how experimental manipulations can link specific categories of pollinators to observed selection on floral traits, and thus improve our understanding of how species interactions shape patterns of selection. 相似文献