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861.
Patricia H. Gude Ray Rasker Kingsford L. Jones Julia H. Haggerty Mark C. Greenwood 《Growth and change》2012,43(3):419-441
The U.S. West has gone through many periods of economic boom and bust, most of which were associated with rapid rises and declines in commodity markets. The recent structural shift toward a primarily service‐based economy begs the question of whether the driving forces behind the cycles of boom and bust also may be shifting away from commodities toward people and their resources. This paper explores several factors that contributed to growth in the 1990s and 2000s: asking whether these factors created any advantages or disadvantages during the most recent recession and whether the shift away from commodity production to a knowledge‐ and human capital‐intensive economy has implications for how local areas experience the boom–bust cycle. 相似文献
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863.
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865.
Woodward G Gessner MO Giller PS Gulis V Hladyz S Lecerf A Malmqvist B McKie BG Tiegs SD Cariss H Dobson M Elosegi A Ferreira V Graça MA Fleituch T Lacoursière JO Nistorescu M Pozo J Risnoveanu G Schindler M Vadineanu A Vought LB Chauvet E 《Science (New York, N.Y.)》2012,336(6087):1438-1440
Excessive nutrient loading is a major threat to aquatic ecosystems worldwide that leads to profound changes in aquatic biodiversity and biogeochemical processes. Systematic quantitative assessment of functional ecosystem measures for river networks is, however, lacking, especially at continental scales. Here, we narrow this gap by means of a pan-European field experiment on a fundamental ecosystem process--leaf-litter breakdown--in 100 streams across a greater than 1000-fold nutrient gradient. Dramatically slowed breakdown at both extremes of the gradient indicated strong nutrient limitation in unaffected systems, potential for strong stimulation in moderately altered systems, and inhibition in highly polluted streams. This large-scale response pattern emphasizes the need to complement established structural approaches (such as water chemistry, hydrogeomorphology, and biological diversity metrics) with functional measures (such as litter-breakdown rate, whole-system metabolism, and nutrient spiraling) for assessing ecosystem health. 相似文献
866.
BACKGROUND: Busseola fusca is a major pest of maize in Africa but unfortunately is difficult to control using chemical insecticides. Insect‐resistant transgenic crops may provide an alternative viable strategy to control this pest. RESULTS: Recombinant Cry1Ab (1%) reduced larval weight by 60% over the trial period, while larval weight in the control group increased by 25%; no effects on mortality were observed. Insect survival, developmental rate and pupal and adult weight were significantly reduced (P < 0.05) on maize expressing Cry1Ab (MON810) compared with the non‐transformed parental line. These differences were more pronounced with second‐instar larvae than with third‐instar larvae. Leaf area consumed by Bacillus thuringiensis (Bt)‐fed larvae was significantly lower (0.5 cm2 larva?1 day?1) compared with the area consumed by control‐fed insects (3.3 cm2 larva?1 day?1). EM studies revealed that consumption of Bt maize deleteriously affected gut integrity. Effects were observed in columnar cells of the midgut epithelium, with the cytoplasm becoming highly vacuolated; the microvilli were disorganised, the mitochondria were abnormal and there was an increase in the number of lysosomal bodies. The rough endoplasmic reticulum had also become dilated. CONCLUSION: This study confirms the potential for Bt maize, when used as part of an IPM programme, for control of B. fusca. Copyright © 2011 Society of Chemical Industry 相似文献
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868.
Franklin MA Rochat MC Payton ME Broaddus KD Bartels KE 《Journal of the American Animal Hospital Association》2012,48(1):18-24
The purpose of this randomized clinical trial was to compare the efficacy of three patient warming devices (i.e., circulating water blanket, forced-air, and warming panels) used either alone or in combination on patients undergoing surgeries lasting >60 min. In total, 238 dogs were included and divided into either the celiotomy or nonceliotomy group. Dogs in each group were further divided into one of three subgroups. Dogs in subgroup 1 (n=39) were placed on a circulating water blanket with a forced-air warming blanket placed over the trunk. Subgroup 2 dogs (n=40) were placed on a forced-air warming blanket only. Subgroup 3 dogs (n=40) were placed on warming panels. Significant temperature drops occurred from time of induction (38.1°C±0.64°C) to the start of surgical procedures (36.7°C±0.95°C). Although body temperature was maintained once the warming units were started in all groups, there were significant differences in temperatures for the type of surgical procedures (i.e., celiotomies versus nonceliotomies) performed over time except for subgroup 3. The warming panels and forced-air devices were equally effective in preserving body temperature in anesthetized patients. 相似文献
869.
Wheelhouse N Howie F Gidlow J Greub G Dagleish M Longbottom D 《Veterinary journal (London, England : 1997)》2012,193(2):586-588
Bovine abortion represents a major animal welfare issue and a cause of substantial economic loss yet the rate of successful diagnosis remains low. Chlamydia-related organisms including Parachlamydia have recently emerged as putative cattle abortifacients. Placental tissue samples and fetal lung from bovine abortion submissions across Scotland in Spring 2011 were investigated by histopathology for the presence of suspect Chlamydia-related organisms. Evidence of Chlamydia-related organisms was observed in 21/113 (18.6%) placenta samples. Thirteen of the suspect cases and 18 histopathology negative cases were analysed by molecular and immunohistochemical methods. All samples were PCR positive for Parachlamydia but sequencing revealed high homology between identified environmental 16S sequences in all but three cases. Parachlamydial antigen was detected in 10/31 placental samples (32.2%) with pathology consistent with chlamydial infection. This work supports the need for further surveillance investigations and experimental studies to determine the role of Parachlamydia in bovine abortion. 相似文献
870.
S Melis S Schauvliege H van Bolhuis M Hoyer F Gasthuys 《Veterinary anaesthesia and analgesia》2012,39(5):520-528
Objective To determine if a combination of detomidine and ketamine can be used for effective chemical immobilization of chimpanzees. Study design Observational study. Animals Twenty‐one adult captive chimpanzees (12 males, nine females), age 8–46 years, weighing 40.4–68.4 kg. Methods The chimpanzees were immobilized with intramuscular (IM) detomidine and ketamine by a darting system. Based on estimated weights, doses administered were 50 μg kg?1 detomidine and 4 mg kg?1 ketamine in groups 1 and 2, and 60 μg kg?1 and 5 mg kg?1 respectively in group 3. Eight minutes in group 1 and 15 minutes in groups 2 and 3 were allowed from the time of apparent immobilization before removing the animals from their enclosures. Body temperature, arterial haemoglobin saturation and pulse rate were measured. The time from injection to induction (recumbency and absence of voluntary movement), total anaesthetic and recovery times (with or without atipamezole) were recorded. Results Immobilization occurred within 5 minutes after darting in most animals. Early handling of the chimpanzees often resulted in arousal and required further doses of ketamine IM. Most animals were hypoxaemic and hypothermic. Occasionally, bradycardia was observed. Atipamezole resulted in an acceptable quality of recovery 10 minutes after IM injection. The duration of immobilization varied widely when no antagonist was administered. Conclusions and clinical relevance The combination detomidine (60 μg kg?1) and ketamine (5–6 mg kg?1) can be used for the immobilization of chimpanzees for non‐ to minimally invasive procedures. A period of 15 minutes should be allowed before handling to avoid unwanted arousal. Oxygen administration is recommended to reduce hypoxaemia. Administration of atipamezole is justified to hasten recovery. 相似文献