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141.
Ralf M. Staebler Sean M. McGinn Brian P. Crenna Thomas K. Flesch Katherine L. Hayden Shao-Meng Li 《Atmospheric environment (Oxford, England : 1994)》2009,43(38):6091-6099
In Canada approximately 45% of ammonia (NH3) emissions are attributed to dairy and beef cattle industries. The present study focused on NH3 emissions from a beef feedlot with a one-time capacity of 17,220 head. The aim was to improve the Canadian NH3 emission inventories and air quality forecasting capabilities. A Cessna 207, equipped with a fast-response NH3/NOy detector and a quadrupole aerosol mass spectrometer, was flown in a grid pattern covering an area of 8 × 8 km centered on a feedlot (800 × 800 m) at altitudes ranging from 30 to 300 m above ground. Stationary ground measurements of NH3 concentration and turbulence parameters were made downwind of the feedlot. Three flights were conducted under varying meteorological conditions, ranging from very calm to windy with near-neutral stratification. NH3 mixing ratios up to 100 ppbv were recorded on the calm day, up to 300 m above ground. An average feedlot NH3 emission rate of 76 ± 4 μg m?2 s?1 (equivalent to 10.2 g head?1 h?1) was estimated. Characteristics of the measured NH3 plume were compared to those predicted by a Lagrangian dispersion model. The spatially integrated pattern of NH3 concentrations predicted and measured agreed but the measured was often more complex than the predicted spatial distribution. The study suggests that the export of NH3 through advection accounted for about 90% of the emissions from the feedlot, chemical transformation was insignificant, and dry deposition accounted for the remaining 10%. 相似文献
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143.
Katherine E. Moseby Hugh McGregor Brydie M. Hill John L. Read 《Conservation biology》2020,34(1):220-231
Spillover effects are an expansion of conservation benefits beyond protected areas through dispersal of species that reside within. They have been well documented in marine but not terrestrial systems. To understand the effects on wildlife created by conservation fences, we explored the internal and external gradients of activity in mammal, reptile, and bird species at a conservation reserve in arid Australia that is fenced to exclude invasive rabbits (Oryctolagus cuniculus), cats (Felis catus), and foxes (Vulpes vulpes). Two methods were used: counts of animal tracks along transects on sand dunes and captures at pitfall-trapping sites. In both cases, sites were spaced at different distances from the reserve fenceline inside and outside the reserve. We recorded a range of spillover, source-sink, step, and barrier effects that combined to create a zone within and around the reserve with fence-induced species-specific wildlife gradients. Two endemic rodents but none of the 4 mammal species reintroduced to the reserve showed positive spillover effects. Barrier effects, where activity was highest close to the fence, were recorded for the feral cat and native bettong (Bettongia lesueur), species that could not breach the fence. In comparison, some reptiles and native mammal species that could permeate the fence displayed source-sink effects; that is, their activity levels were reduced close to the fence likely due to constant emigration to the side with lower density. Activity of some reptiles was lowest at sites inside the reserve and gradually increased at outside sites with distance from the fence, a gradient likely related to trophic cascades triggered by predator exclusion. Our result shows that fenced reserves can create overlapping layers of species-specific gradients related to each species’ ability to permeate the fence and its varying susceptibility to threats. Managers should be aware that these gradients may extend for several kilometers either side of the fence and that not all contained species will increase in abundance. Creating wider conservation benefits may require increased fence permeability and threat reduction outside the fence. 相似文献
144.
Sherry L. Krayesky Janna L. Mahoney Katherine M. Kinler Stacey Peltier Warnesha Calais Kate Allaire Glen M. Watson 《Marine Biology》2010,157(5):1041-1047
Test probes were touched to tentacles to investigate whether discharge of spirocysts likely is regulated by hair bundle mechanoreceptors.
Significantly more spirocysts discharge onto test probes in the presence of vibrations at 11–15 Hz as compared to 0 Hz. Adding
N-acetylneuraminic acid, NANA, shifts maximal discharge of spirocysts upwards to 36–40 Hz, and possibly to 21–25 Hz. In contrast,
NANA shifts maximal discharge of basitrichous isorhiza nematocysts downwards to 1–20 Hz. Thus, discharge of cnidae (‘stinging
capsules’) is differentially regulated according to the type of cnida. Furthermore, it appears that chemodetection of N-acetylated sugars is not a prerequisite to capturing prey because, in seawater alone, maximal discharge of cnidae occurs
at frequencies overlapping movements of calmly swimming prey. Nevertheless, chemodetection of N-acetylated sugars broadens the range of frequencies stimulating maximal discharge of cnidae and, therefore, likely enhances
prey capture. 相似文献
145.
Katherine P. Prem Dedy Ng M. Sam Mannan 《Journal of Loss Prevention in the Process Industries》2010,23(4):549-560
Analyzing historical databases can provide valuable information on the incident occurrences and their consequences for assessing the safety of the chemical process industry. In this study, the RMP and HSEES databases were utilized to understand the patterns and the factors influencing chemical process industry incidents. Frequency exceedance curves were generated by utilizing the different incident consequences from the databases to understand the profile of societal loss from reported incidents. Understanding the statistics and trends of the historical incidents could serve as important lagging indicators in order to assess the probable proximity to major consequences from the low-probability/high-consequence incidents. To this regard, the safety pyramids were also generated to better understand the relationship between the different consequences of the reported incidents. Furthermore, the safety pyramids were analyzed in comparison with the traditional safety pyramid proposed by Heinrich to understand the US process industry incident occurrence trends. 相似文献
146.
A method was developed for the simultaneous determination of almost 40 pharmaceuticals; including antidepressants, non-steroidal anti-inflammatories, analgesics, hypolipidemics, α- and β-blockers, an anti cancer drug, anti-fungal agents, an opiate, an antibiotic, an anti-coagulant, a diuretic, an anti-anginal and an anti-diabetic compound. This was used to assess the contribution of pharmaceuticals originating from hospital effluents to one of Oslo city's wastewater treatment works. Some pharmaceuticals were found to contribute to more of the wastewater loading than others. 11% of the propranolol entering the wastewater treatment works stems from hospital effluent, approximately 2% of the atenolol, carbemazepine, metaprolol and atorvastatin, and for several other compounds the contribution is less than 1%.This assessment shows that point sources discharges from hospitals typically make a small contribution to the overall pharmaceutical load when compared to municipal areas, however this varies from substance to substance and is not the case when a drug's use is primarily hospital based. 相似文献
147.
Katherine L. Meierdiercks James A. Smith Mary Lynn Baeck Andrew J. Miller 《Journal of the American Water Resources Association》2010,46(6):1221-1237
Meierdiercks, Katherine L., James A. Smith, Mary Lynn Baeck, and Andrew J. Miller, 2010. Heterogeneity of Hydrologic Response in Urban Watersheds. Journal of the American Water Resources Association (JAWRA) 46(6):1221–1237. DOI: 10.1111/j.1752-1688.2010.00487.x Abstract: The changing patterns of streamflow associated with urbanization are examined through analyses of discharge and rainfall records for the study watersheds of the Baltimore Ecosystem Study (BES). Analyses utilize a decade (1999-2008) of observations from a dense U.S. Geological Survey stream gaging network and Hydro-NEXRAD radar rainfall fields. The principal study watershed of the BES is Gwynns Falls (171 km2). Focus is given to two Gwynns Falls basins with contrasting patterns and histories of development, Dead Run and Upper Gwynns Falls. The sharp contrasts in streamflow properties between the basins reflect the differences in urban development prior to implementation of stormwater management regulations (much of Dead Run) and development for which stormwater management is an integral part of the hydrologic system (Upper Gwynns Falls). The mean annual runoff in Dead Run (558 mm) is 35% larger than that of Upper Gwynns Falls; larger contrasts in runoff properties typify the “warm season” and are linked to storm event hydrologic response. Spatial heterogeneities in storm event response are reflected in seasonal and diurnal properties of streamflow. Analyses of storm event response are presented for June 2006, during which monthly rainfall over the BES region ranged from less than 150 to more than 500 mm. Baisman Run, the BES forest reference watershed, and Moores Run, a highly urbanized watershed in Baltimore City, provide “end-member” representations of urban impacts on streamflow. 相似文献
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149.
Prakesh S. Shah Susan Blaser Ants Toi Katherine Fong Phyllis Glanc Riyana Babul-Hirji James Rutka David Chitayat 《黑龙江环境通报》2005,25(7):539-542
We describe the finding of cavum veli interpositi (CVI) on fetal ultrasound and MRI and the postnatal MRI and developmental follow-up in two cases. The first case was diagnosed on fetal ultrasound at 33 weeks' gestation and confirmed on fetal MRI. No abnormalities were detected on postnatal examinations and the brain MRI at 1 year of age showed no changes. At 4 years of age, his growth and development were normal. The second case was diagnosed with CVI on fetal ultrasound and MRI at 33.5 weeks' gestation. Postnatal examination showed no abnormalities, and brain MRI at 8 months of age revealed that the CVI was unchanged, but there was a dilated cavum septum pellucidum and cavum vergae. Her growth and development during the first 4 years of life were normal. CVI is a rare fetal ultrasound finding, which seems to be benign. However, further neurodevelopmental follow-up is needed to confirm this observation. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
150.