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51.
52.
Two Pheromones of Coniferophagous Bark Beetles Found in the Bark of Nonhost Angiosperms 总被引:4,自引:0,他引:4
Dezene P. W. Huber Regine Gries John H. Borden Harold D. Pierce Jr. 《Journal of chemical ecology》1999,25(4):805-816
Volatiles from fresh bark of black cottonwood, Populus trichocarpa; trembling aspen, P. tremuloides; paper birch, Betula papyrifera; bigleaf maple, Acer macrophyllum; red alder, Alnus rubra; and Sitka alder, Alnus viridis, were collected on Porapak Q and subjected to coupled gas chromatographic–electroantennographic detection analyses by utilizing the antennae of several scolytid beetles (Dendroctonus pseudotsugae, D. rufipennis, D. ponderosae, Ips pini, and Dryocoetes confusus). Among the antennally active volatiles identified by coupled gas chromatographic-mass spectroscopic analysis were frontalin, 1,5-dimethyl-6,8-dioxabicyclo[3.2.1]-octane, in the two Alnus species and conophthorin, (E)-7-methyl-1,6-diox-aspiro[4.5]decane, in the other four species. Field trapping experiments demonstrated that conophthorin had a significant disruptant effect on the response to a pheromone-host kairomone blend by both Dendroctonus pseudotsugae and D. ponderosae. Our results, and the recent identification of other scolytid pheromones in various tree species, pose major questions regarding the evolution and ecological roles of these semiochemicals, including the possibility of Batesian mimicry by the beetles. They also suggest a need for comparative studies on the biosynthetic pathways for these compounds. 相似文献
53.
MS Pearle HL Pierce GL Miller JA Summa JM Mutz BA Petty CG Roehrborn JV Kryger SY Nakada 《Canadian Metallurgical Quarterly》1998,160(4):1260-1264
PURPOSE: We compare the efficacy of percutaneous nephrostomy with retrograde ureteral catheterization for renal drainage in cases of obstruction and infection associated with ureteral calculi. MATERIALS AND METHODS: We randomized 42 consecutive patients presenting with obstructing ureteral calculi and clinical signs of infection (temperature greater than 38 C and/or white blood count greater than 17,000/mm.3) to drainage with percutaneous nephrostomy or retrograde ureteral catheterization. Preoperative patient and stone characteristics, procedural parameters, clinical outcomes and costs were assessed for each group. RESULTS: Urine cultures obtained at drainage were positive in 62.9% of percutaneous nephrostomy and 19.1% of retrograde ureteral catheterization patients. There was no significant difference in the time to treatment between the 2 groups. Procedural and fluoroscopy times were significantly shorter in the retrograde ureteral catheterization (32.7 and 5.1 minutes, respectively) compared with the percutaneous nephrostomy (49.2 and 7.7 minutes, respectively) group. One treatment failure occurred in the percutaneous nephrostomy group, which was successfully salvaged with retrograde ureteral catheterization. Time to normal temperature was 2.3 days in the percutaneous nephrostomy and 2.6 in the retrograde ureteral catheterization group, and time to normal white blood count was 2 days in the percutaneous nephrostomy and 1.7 days in the retrograde ureteral catheterization group (p not significant). Length of stay was 4.5 days in the percutaneous nephrostomy group compared with 3.2 days in the retrograde ureteral catheterization group (p not significant). Cost analysis revealed that retrograde ureteral catheterization was twice as costly as percutaneous nephrostomy. CONCLUSIONS: Retrograde ureteral catheterization and percutaneous nephrostomy effectively relieve obstruction and infection due to ureteral calculi. Neither modality demonstrated superiority in promoting a more rapid recovery after drainage. Percutaneous nephrostomy is less costly than retrograde ureteral catheterization. The decision of which mode of drainage to use may be based on logistical factors, surgeon preference and stone characteristics. 相似文献
54.
Objectives
California experienced a notable decline in per capita cigarette consumption during its comprehensive tobacco control programme. This study examines what proportion of the decline occurred from: (1) fewer ever smokers in the population, (2) more ever smokers quitting, and (3) current smokers smoking less.Design, subjects
Per capita cigarette consumption computed from cigarette sales and from adult respondents to the large, cross‐sectional, population‐based California Tobacco Surveys of 1990 (n = 24 296), 1996 (n = 18 616) and 2002 (n = 20 525) were examined for similar trends.Main outcome measure
Changes (period 1: 1990–1996; period 2: 1996–2002) in per capita cigarette consumption from self‐reported survey data were partitioned for the entire population and for demographic subgroups into the three components mentioned above.Results
In periods 1 and 2, most of the decline in per capita cigarette consumption for the population as a whole was from current smokers smoking less followed by a reduction in ever smokers. The decline from smokers smoking less was particularly evident among young adults (18–29 years) in period 1. While the portion of the decline due to quitting in the entire population in period 1 was negligible, in period 2 it accounted for 22% of the total per capita decline. The decline from quitting in period 2 was mostly observed among women.Conclusions
Rather than near‐term benefits from smokers quitting, population health benefits from reduced per capita cigarette consumption will likely occur over the longer term from fewer people becoming ever smokers, and more less‐addicted smokers eventually quitting successfully. 相似文献55.
Jose-Luis Molina Sergio Martos-Rosillo Crisanto Martín-Monta?és Suzanne Pierce 《Water Resources Management》2012,26(10):2951-2971
Integrated Aquifers Management (IAM) demands innovative tools and methods that are able to consider as much perspectives as possible. This research is aimed to design, apply and provide an indicator named Social Sustainable Aquifer Yield (SSAY), expressed in units of time that includes pure hydrological variables as well as social ones. The indicator is defined as the relation between the Residence Time, which is the relation between aquifer Storage (S) and Recharge (R) (S/R), and the relation between the aquifer Pumping (P) and the new variable named Aquifer Social Yield (ASY). The whole indicator is defined by this formula: (S/R)/(P/ASY). The assessment of the residence time is essential in aquifers with at least one of the following features: i) high hydraulic diffusivity, and ii) small volume of reserves. Finally, the variable ASY is defined as the average perception from the stakeholders about the maximum acceptable aquifer exploitation. This indicator has been successfully applied in the aquifers located in southern Jaen province (South Spain) belonging to the Water System SE4-Jaén Water Supply. The results probe the high utility of the indicator, especially in regards to the public participation processes. 相似文献
56.
NI Strelkova AT Gavrilkov NF Diuzhilova EN Strel'tsova 《Canadian Metallurgical Quarterly》1981,81(8):1162-1166
Results of treating 181 patients for hemiparesis after a cerebral stroke or a craniocerebral injury by local exposure of the pathological focus to decimeter electromagnetic waves (DW) and alternating magnetic field (AMF) are presented. It is shown that these treatment methods improve the cerebral circulation and contribute to earlier restoration of the motor functions, especially, if used in combination with sulfide baths, therapeutic physical exercises and massage. The therapeutic effectiveness of the DW- and AMF-therapy is confirmed objectively by so informative examination methods, as rheoencephalography, ultrasonic dopplerography, and thermography. 相似文献
57.
A new model for the static polarisability tensor elements of small particles is proposed and investigated. The static polarisability tensor for nearly agglomerated and agglomerated homogeneous dielectric spheres is investigated using a numerical procedure. Excellent agreement is obtained with a recent theoretical formulation for the slightly separated case.<> 相似文献
58.
J. Hensman R. Mills S.G. Pierce K. Worden M. Eaton 《Mechanical Systems and Signal Processing》2010,24(1):211-223
A standard technique in the field of non-destructive evaluation is to use acoustic emissions to characterise and locate the damage events that generate them. The location problem is typically posed in terms of the times of flight of the waves and results in an optimisation problem, which can at times be ill-posed. A method is proposed here for learning the relationship between time of flight differences and damage location using data generated by artificially stimulated acoustic emission (AE)—a classic problem of regression. A structure designed to represent a complicated aerospace component was interrogated using a laser to thermoelastically generate AE at multiple points across the structure's surface. Piezoelectric transducers were mounted on the surface of the structure, and the resulting waveforms were recorded. A Gaussian process (GP) with RBF kernels was chosen for regression. Since during AE monitoring not all events can be guaranteed to be detected by all sensors, a GP was trained on data for all possible combinations (subsets) of sensors. The inputs to the GPs were the differences in time of flight between sensors in the set, and the targets were the locations of the source of ultrasonic stimulation. Subsequent (test) data points were located by every possible GP, given the active sensors. It is shown that maps learned on a given structure can generalise effectively to nominally identical structures. 相似文献
59.
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