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91.
ABSTRACT We estimated loss of butt-end leg bands on male wild turkeys (Meleagris gallapavo) captured in New York, Ohio, and Pennsylvania (USA) during December-March, 2006–2008. We used aluminum rivet leg bands as permanent marks to estimate loss of regular aluminum, enameled aluminum, anodized aluminum, and stainless steel butt-end leg bands placed below the spur. We used band loss information from 887 turkeys recovered between 31 days and 570 days after release ( = 202 days). Band loss was greater for turkeys banded as adults (>1 yr old) than juveniles and was greater for aluminum than stainless steel bands. We estimated band retention was 79–96%, depending on age at banding and type of band, for turkeys recovered 3 months after release. Band retention was <50% for all age classes and band types 15 months after banding. We concluded that use of butt-end leg bands on male wild turkeys is inappropriate for use in mark-recapture studies.  相似文献   
92.
Abstract Motorized recreation in North American wildlands is increasing, and technological developments in the power and range of vehicles has increased access to high-elevation habitats. The American marten (Martes americana) is vulnerable to this disturbance because martens, like other residents of high-elevation forests, are associated with remote wilderness conditions where the presence of motorized vehicles is a recent phenomenon. We evaluated the effects of vehicles at 2 study sites in California, USA, by comparing marten occupancy rates and probabilities of detection in areas where recreational vehicle use is legal and encouraged (use areas) with wilderness areas where vehicles are prohibited (non-use areas). We sampled vehicle occurrence in nearby use and non-use areas using sound level meters and determined marten occurrence using track and camera stations. We also included 2 secondary measures of potential effects of vehicles on martens: sex ratio and circadian pattern of activity. Martens were ubiquitous in use and non-use areas in both study sites, and there was no effect of vehicle use on marten occupancy or probability of detection. We predicted that females might be less common and martens more nocturnal in use than in non-use areas, but neither occurred. Martens were exposed to low levels of disturbance in our study sites. We estimated that a marten might be exposed to 0.5 vehicle passes/hour and that this exposure had the greatest effect on <20% of a typical home range area. Furthermore, vehicle use usually occurred when martens were inactive. We did not measure behavioral, physiological, or demographic responses, so it is possible that vehicles may have effects, alone or in concert with other threats (e.g., timber harvest), that we did not quantify. We encourage additional studies to determine whether other montane species that are year-round residents demonstrate the same response to motorized vehicles.  相似文献   
93.
SUMMARY.
  • 1 Microhabitat use by Blennius fluviatilis in the Río Matarraña, Spain, varied significantly among dates during a 19-month study. Most temporal variation, however, was attributable to changes in microhabitat availability.
  • 2 B. fluviatilis demonstrated non-random use of available microhabitats during each sampling period, and generally occupied deeper microhabitats with higher average current velocities dominated by rubblegravel substrates.
  • 3 B. fluviatilis also demonstrated non-random use of available nest sites; males generally nested under the largest available pieces of rubble, in areas with less gravel or sand. Water column depth influenced nest site use in two of four study areas.
  • 4 We found few microhabitat differences between spawning and nonspawning periods, or between males and females. In addition, microhabitat use was similar among B. fluviatilis size-groups.
  • 5 Although B. fluviatilis often were over-represented in deeper, erosional areas, blennies necessarily inhabited a wide range of microhabitats because average current velocities and water depths fluctuated greatly during the study. Tolerance of a broad range of environmental conditions may contribute to the species' persistence in habitats that exhibit extreme seasonal changes in discharge such as the Matarraña.
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94.
The Mahalanobis distance and elliptic distributions   总被引:3,自引:0,他引:3  
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95.
A new inexpensive suction apparatus for sampling arthropods in grassland   总被引:2,自引:0,他引:2  
Abstract.
  • 1 We describe a new technique for sampling arthropods from grassland and other vegetation, using a modified petrol-driven suction apparatus called a‘Blow & Vac’.
  • 2 The new apparatus was tested by comparing its efficiency in extracting arthropods from vegetation with that of a conventional Dietrick, or‘D-Vac’, suction sampler.
  • 3 Unimpeded air velocity inside the suction tube was approximately 4 times that of the D-Vac.
  • 4 In field trials on semi-natural grasslands, the Blow & Vac caught more individuals of most spider and certain beetle species compared to the D-Vac and approximately equal numbers of Auchenorrhyncha.
  • 5 We conclude that the‘Blow & Vac’has considerable potential for sampling arthropod populations. Its low cost and weight make it a suitable alternative to the conventional D-Vac apparatus.
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96.
The compound 5-chloro-3-methyl-4-nitro-1H-pyrazole (CMNP) is a pyrazole-derivative that induces abscission selectively in mature citrus (Citrus sinensis) fruit when applied to the canopy and has herbicidal activity on plants when applied to roots. Despite the favourable efficacy of this compound, the mode of action remains unknown. To gain information about the mode of action of CMNP, the effect of application to mature citrus fruit and Arabidopsis thaliana roots was explored. Peel contact was essential for mature fruit abscission in citrus, whereas root drenching was essential for symptom development and plant decline in Arabidopsis. CMNP was identified as an uncoupler in isolated soybean (Glycine max) mitochondria and pea (Pisum sativum) chloroplasts and an inhibitor of alcohol dehydrogenase in citrus peel, but not an inhibitor of protoporphyrinogen IX oxidase. CMNP treatment reduced ATP content in citrus peel and Arabidopsis leaves. Phospholipase A2 (PLA2) and lipoxygenase (LOX) activities, and lipid hydroperoxide (LPO) levels increased in flavedo of citrus fruit peel and leaves of Arabidopsis plants treated with CMNP. An inhibitor of PLA2 activity, aristolochic acid (AT), reduced CMNP-induced increases in PLA2 and LOX activities and LPO levels in citrus flavedo and Arabidopsis leaves and greatly reduced abscission in citrus and delayed symptoms of plant decline in Arabidopsis. However, AT treatment failed to halt the reduction in ATP content. Reduction in ATP content preceded the increase in PLA2 and LOX activities, LPO content and the biological response. The results indicate a link between lipid signalling, abscission in citrus and herbicidal damage in Arabidopsis.  相似文献   
97.
Petioles of Sinapis cotyledons cultured in 6x10–2 M sucrosein the light increased 28-fold in total carbohydrate contentover a 7-d period compared with an 8-fold increase in petiolesof cotyledons cultured on water. The starch and reducing sugarfractions were the major components of this accumulation. Labelledsucrose applied to the petiole base moved quickly up the petioleand into the main veins of the lamina. Some basipetal redistributionoccurred subsequently and after 24 h radioactivity accumulatedstrongly at the petiole base. Culture in sucrose reduced basalaccumulation and increased acropetal movement of the label. Fixation of 14CO2 by petioles remained constant when cotyledonswere cultured in water, whereas in sucrose, fixation fell by50 per cent during the first 2 d. The pattern of inhibitionof fixation matched the pattern of sucrose distribution in thepetiole. Petiolar chlorophyll content remained constant in controlsbut fell rapidly after 4 d culture in sucrose. The results are discussed in relation to the role of petiolarcarbohydrate accumulation in the regulation of CO2 fixation,primordium development, and senescence in this system.  相似文献   
98.
The relationship of total body length to formalin dry weight for individuals of Thermo-cyclops hyalinus and Mesocyclops leuckarti, from the tropical Lake George, Uganda, is given and shows that previous estimates of individual biomass and, therefore, of zooplankton standing crop and production based on them, were too high. The annual mean standing crop of total Crustacea, in 1969–70 was 828 mg (dw) m?2 and for T. hyalinus, the dominant species, 559 mg (dw) m?2 Biomass tended to be higher in the mid-lake area than inshore. The annual mean production of T. hyalinus is now estimated to be 44 mg (dw) m?2 day.  相似文献   
99.
The RNA content of a population of Tetrahymena pyriformis W was followed during the growth phases of the culture. The cellular RNA levels were found to reach a maximum in early log phase and to decrease throughout the remainder of the log and deceleration phases. There was a 25% decrease in RNA amount when cells in late stationary phase were compared to those in deceleration. This loss of RNA was mimicked when cells from the deceleration phase were suspended in a non-nutrient buffered medium. Procedures were established to determine RNA content and the intra- and extracellular distribution of RNA degradation products, namely purine and pyrimidine bases and orthophosphate. Balance sheets are presented to show that the decrease in RNA levels was accompanied by an equivalent increase in purine and pyrimidine bases and phosphorus derivatives. The validity of the procedures employed was demonstrated. The influence of magnesium, cholesterol and glucose on the cells suspended in a non-nutrient buffer was examined. Each was found to affect the ultimate distribution of RNA products in a characteristic fashion suggesting that each compound acts by a different mode of action.  相似文献   
100.
A relatively simple phenol extraction method, with EDTA as the nuclease inhibitor, is described for the isolation of purified, highly polymerized native DNA from Trichomonas vaginalis, Trichomonas gallinae, and Tritrichomonas foetus; it is applicable also to Tetrahymena pyriformis. RNase Tl, RNase A (Worthington's R), pronase, and α-amylase digestions constitute important steps in obtaining satisfactory yields of DNA. High degree of polymerization of the isolation product was estimated by hyperchromicity at O.D.260 after DNase treatment and by CsCl gradient analysis. The double-stranded condition of the DNA samples was estimated by the latter method and by denaturation with NaOH, and the molecular weight by sucrose gradient analysis. Purity of the samples was determined spectrophotometrically and by chemical analyses for protein and glycogen. DNA percent recovery was estimated by the diphenylamine reaction.  相似文献   
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