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71.
Effects of forest patch size on avian diversity 总被引:8,自引:2,他引:8
Nancy E. McIntyre 《Landscape Ecology》1995,10(2):85-99
The effects of landscape patchiness on the diversity of birds of the Georgia Piedmont were investigated during 1993. Birds were sampled along line transects within relatively large (10–13.25 ha) and small (less than 3.25 ha) forest patches located within nonforest agricultural landscapes. Patterns of habitat use in these patches were compared to those in contiguous forest patches larger than 13.25 ha. Analysis of variance revealed significant differences in diversity between large and small woodlots and between contiguous and fragmented landscapes, especially in terms of the numbers of edge and interior species and winter-resident, summer-resident, and year-round birds observed. 相似文献
72.
John M. MacGregor John E. Rush Nancy J. Laste Rebecca L. Malakoff Suzanne M. Cunningham Natalie Aronow Daniel J. Hall Justin Williams Lori L. Price 《Journal of Veterinary Cardiology》2011,13(4):251-260
Hypothesis/ObjectivesTo describe the therapeutic use of pimobendan in cats, describe the patient population to which it was administered, document potential side effects and report the clinical course following administration of pimobendan in conjunction with standard heart failure therapy. It is hypothesized that cats with advanced heart disease including congestive heart failure from a variety of causes will tolerate pimobendan with a minimum of side effects when used in treatment in conjunction with a variety of other medications.Animals, materials and methodsOne hundred and seventy client owned cats with naturally occurring heart disease, one hundred and sixty four of which had congestive heart failure. Medical records were reviewed and owners and referring veterinarians were contacted for follow-up data. Data collected included pimobendan dose, other medications administered concurrently, data collected at physical examination, presence or absence of heart failure, adverse effects, classification of heart disease, echocardiographic data and survival time. The data were analyzed for significance between the initial visit and any follow-up visits.ResultsAll cats were treated with pimobendan. The median pimobendan dose was 0.24 mg/kg q 12 h. Pimobendan was used in combination with multiple concurrent medications including angiotensin converting enzyme inhibitors, diuretics and anti-thrombotics. Five cats (3.0%) had potential side effects associated with pimobendan. One cat (0.6%) had presumed side effects severe enough to discontinue pimobendan use. Median survival time for 164 cats with congestive heart failure after initiation of pimobendan was 151 days (range 1–870).ConclusionPimobendan appears to be well tolerated in cats with advanced heart disease when used with a variety of concurrent medications. Randomized controlled studies need to be performed to accurately assess whether it is efficacious for treatment of congestive heart failure in cats. 相似文献
73.
Two demonstration sites in southeast Idaho were used to extend the scope of remote sensing of leafy spurge research toward investigating coarser scale detection limits. Hyperspectral images were obtained to produce baseline leafy spurge maps, from which spatially and/or spectrally degraded images were subsequently derived for comparative purposes with Landsat 5 Thematic Mapper (TM). The baseline presence/absence maps had an overall accuracy of 67% at the Spencer study site and 85% at the Medicine Lodge study site. Unexpectedly high-accuracy results were produced from the images that were spectrally degraded to the bandwidths of Landsat 5 TM, which suggests that high spectral resolution is not critical to leafy spurge detection. However, a classification using a Landsat 5 TM image indicates that the sensor is inadequate for regional distribution monitoring. The differences in results between the actual and degraded images suggest that a sensor with comparable resolutions but improved instrumentation (e.g., signal to noise) may offer an alternative to hyperspectral data for mapping leafy spurge at regional scales. 相似文献
74.
As a cover crop, buckwheat (Fagopyrum esculentum) may increase soil‐P availability. Buckwheat was grown in low‐P and P‐fertilized field plots, and organic anions were measured in rhizosphere soil. Soil‐P availability was not affected by buckwheat, but the concentration of rhizosphere tartrate2– was significantly higher (p < 0.005) in low‐P vs. P‐fertilized plots. This suggests that organic‐anion root exudation may have a role in buckwheat‐rhizosphere P dynamics. 相似文献
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76.
A perspective on management of Helicoverpa armigera: transgenic Bt cotton,IPM, and landscapes 下载免费PDF全文
Sharon Downes Darren Kriticos Hazel Parry Cate Paull Nancy Schellhorn Myron P Zalucki 《Pest management science》2017,73(3):485-492
Helicoverpa armigera is a major pest of agriculture, horticulture and floriculture throughout the Old World and recently invaded parts of the New World. We overview of the evolution in thinking about the application of area‐wide approaches to assist with its control by the Australian Cotton Industry to highlight important lessons and future challenges to achieving the same in the New World. An over‐reliance of broad‐spectrum insecticides led to Helicoverpa spp. in Australian cotton rapidly became resistant to DDT, synthetic pyrethroids, organophosphates, carbamates and endosulfan. Voluntary strategies were developed to slow the development of insecticide resistance, which included rotating chemistries and basing spray decisions on thresholds. Despite adoption of these practices, insecticide resistance continued to develop until the introduction of genetically modified cotton provided a platform for augmenting Integrated Pest Management in the Australian cotton industry. Compliance with mandatory resistance management plans for Bt cotton necessitated a shift from pest control at the level of individual fields or farms towards a coordinated area‐wide landscape approach. Our take‐home message for control of H. armigera is that resistance management is essential in genetically modified crops and must be season long and area‐wide to be effective. © 2016 Society of Chemical Industry 相似文献
77.
Sheep were dosed orally with diazinon at 450 and 600 mg/kg: residues of diazinon were determined in the blood, brain, liver, kidney cortex and medulla, muscle, fat and rumen contents at intervals after dosing, and cholinesterase activities in the erythrocytes and the brain were determined at the same intervals. The relations between residues, cholinesterase activity and clinical symptoms are discussed from the points of view of their diagnostic value and the possibility of undesirable residues occurring in poisoned animals. Rough estimates of the residues of two metabolites, hydroxydiazinon and dehydro-diazinon, in one sheep are also discussed. The oxygen analogue of diazinon was not detected although it was specifically sought. 相似文献
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80.
Lim HS Ko TS Hobbs HA Lambert KN Yu JM McCoppin NK Korban SS Hartman GL Domier LL 《Phytopathology》2007,97(3):366-372
ABSTRACT Transgenic soybean (Glycine max) plants expressing Soybean mosaic virus (SMV) helper component-protease (HC-Pro) showed altered vegetative and reproductive phenotypes and responses to SMV infection. When inoculated with SMV, transgenic plants expressing the lowest level of HC-Pro mRNA and those transformed with the vector alone initially showed mild SMV symptoms. Plants that accumulated the highest level of SMV HC-Pro mRNA showed very severe SMV symptoms initially, but after 2 weeks symptoms disappeared, and SMV titers were greatly reduced. Analysis of SMV RNA abundance over time with region-specific probes showed that the HC-Pro region of the SMV genome was degraded before the coat protein region. Transgenic soybean plants that expressed SMV HC-Pro showed dose-dependent alterations in unifoliate leaf morphologies and seed production where plants expressing the highest levels of HC-Pro had the most deformed leaves and the lowest seed production. Accumulation of microRNAs (miRNAs) and mRNAs putatively targeted by miRNAs was analyzed in leaves and flowers of healthy, HC-Pro-transgenic, and SMV-infected plants. Neither expression of SMV HC-Pro nor SMV infection produced greater than twofold changes in accumulation of six miRNAs. In contrast, SMV infection was associated with twofold or greater increases in the accumulation of four of seven miRNA-targeted mRNAs tested. 相似文献