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21.
R.T. Jones T. Bogue B.E. Evans M. Kornicer A.R. Dzierba R. Gardner J.L. Gunter D. Krop R. Lindenbusch D.R. Rust E. Scott P. Smith C. Steffen S. Teige D.S. Armstrong J.H.D. Clark L.J. Kaufman D.J. Steiner E. Frlez D. Pocanic J.J. Kolata L.O. Lamm G. Rogachev C. Campbell E. Collins L. McGlinchey P. Rubin E. Walker G.S. Adams J. Napolitano H. Crannell D.I. Sober R.R. Mammei E.S. Smith 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2007,570(3):384-398
We describe the design and operation of a detector system for measuring all-photon decays of mesons photoproduced in a tagged photon beam with energies between 4.3 and 5.4 GeV and a flux of 5×107 tagged photons per second. Photons from meson decays were detected with a lead-glass calorimeter with an energy resolution of 11% at 1 GeV. Various veto and trigger components were also present. Final states with as many as six photons were successfully detected and reconstructed. 相似文献
22.
Trail pheromones mediate communication among western subterranean termites, Reticulitermes hesperus Banks. Repetitive passages of ≥28 termites were required to establish a pheromone trail and trails needed to be reinforced
because they lasted <48 hr. The minimal threshold concentration for inducing responses from termite workers and secondary
reproductives was between 0.01 and 0.1 fg/cm of (3Z,6Z,8E)-dodecatrien-1-ol (henceforth, dodecatrienol). Workers showed optimal trail-following behavior to dodecatrienol at a concentration
of 10 fg/cm. Trails with concentrations >10 pg/cm were repellent to workers. Workers did not detect pheromone gradients, responding
equally to increasing or decreasing gradients of dodecatrienol, and termite workers were not able to differentiate between
different concentrations of dodecatrienol. Termites preferred dodecatrienol trails to 2-phenoxyethanol trails. Antennae played
a key role in trail pheromone perception. Dodecatrienol acted as an arrestant for worker termites (10 fg/cm2) and male alates (5 ng/cm2), whereas sternal gland extracts from females attracted male alates. Workers and alates, upon contact with filter paper disks
treated with higher doses (10 fg/cm2 and 5 ng/cm2, respectively) of dodecatrienol, were highly excited (increased antennation and palpation) and repeatedly returned to the
treated disks. Dodecatrienol did not act as a phagostimulant when offered on a paper towel disk. Reticulitermes hesperus is highly responsive to dodecatrienol, and it may play an important role in orientation of workers and alates. 相似文献
23.
Runoff of pyrethroid insecticides from concrete surfaces following simulated and natural rainfalls 总被引:1,自引:0,他引:1
Intensive residential use of insecticides has resulted in their ubiquitous presence as contaminants in urban surface streams. For pest eradication, urban hard surfaces such as concrete are often directly treated with pesticides, and wind/water can also carry pesticides onto hard surfaces from surrounding areas. This study expanded on previous bench-scale studies by considering pesticide runoff caused by irrigation under dry weather conditions and rain during the wet season, and evaluated the effects of pesticide residence time on concrete, single versus recurring precipitations, precipitation intensity, and concrete surface conditions, on pesticide transferability to runoff water. Runoff from concrete 1 d after pesticide treatment contained high levels of bifenthrin (82 μg/L) and permethrin (5143 μg/L for cis and 5518 μg/L for trans), indicating the importance of preventing water contact on concrete after pesticide treatments. Although the runoff transferability quickly decreased as the pesticide residence time on concrete increased, detectable residues were still found in runoff water after 3 months (89 d) exposure to hot and dry summer conditions. ANOVA analysis showed that precipitation intensities and concrete surface conditions (i.e., acid wash, silicone seal, stamping, and addition of microsilica) did not significantly affect the pesticide transferability to runoff. For concrete slabs subjected to natural rainfalls during the winter wet season, pesticide levels in the runoff decreased as the time interval between pesticide application and the rain event increased. However, bifenthrin and permethrin were still detected at 0.15-0.17 and 0.75-1.15 μg/L in the rain runoff after 7 months (221 d) from the initial treatment. In addition, pesticide concentrations showed no decrease between the two rainfall events, suggesting that concrete surfaces contaminated by pesticides may act as a reservoir for pesticide residues, leading to sustained urban runoff contamination. 相似文献
24.
Incubation of curing brines for the production of ready-to-eat, uncured, no-nitrite-or-nitrate-added, ground, cooked and sliced ham 总被引:1,自引:0,他引:1
Salt concentration, vegetable juice powder (VJP) concentration and temperature were investigated to determine necessary conditions for incubation of curing brines including VJP and a starter culture containing Staphylococcus carnosus prior to production of naturally cured, no-nitrate/nitrite-added meat products. Subsequently, incubated brines were utilized to produce no-nitrate/nitrite-added sliced ham in which quality characteristics and residual nitrite concentrations were measured to determine feasibility of brine incubation for nitrate conversion prior to injection. Two ham treatments (one with VJP and starter culture; one with pre-converted VJP) and a nitrite-added control were used. No differences (P>0.05) were found for color in the VJP treatments. Control sliced ham was redder after 42 days of storage, retaining significantly (P<0.05) greater a* (redness) than either of the VJP treatments. Residual nitrite concentration was greater (P<0.05) in the control hams during the first week of storage. While the nitrite-added control retained greater red color and initially had more residual nitrite than the VJP treatments, the two VJP treatments did not differ from each other. 相似文献
25.
The results of Deep Brain Stimulation in deafferentation pain syndromes, in particular in thalamic pain, indicate that excellent long-term pain relief can hardly ever be achieved. We report 7 cases using Motor-Cortex-Stimulation for treating severe trigeminal neuropathic pain syndromes, i.e., dysaesthesia, anaesthesia dolorosa and postherpetic neuralgia. The first implantation of the stimulation device for precentral cerebral stimulation was performed in June 1993, the last in September 1995. In all but one case the impulse-generator was implanted after a successful period of test stimulation. Successful means a pain reduction of more than 50% as assessed with a Visual Analogue Scale. Excluding one case, in whom a prolonged focal seizure resulting in a postictal speech arrest occurred during test stimulation, there have been no operative complications and the postoperative course was uneventful. In all the other patients the pain inhibition appeared below the threshold for producing motor effects. Initially these patients reported a good to excellent pain relief. In three of 6 patients a good to excellent pain control was maintained for a follow-up period of 5 months to 2 years. In the remaining three patients the positive effect decreased over several months. 相似文献
26.
BG Bylsma S Abachi P Baringer De Bonte R D Koltick FJ Loeffler EH Low RL McIlwain DH Miller CR Ng LK Rangan EI Shibata M Derrick KK Gan P Kooijman JS Loos B Musgrave LE Price J Repond K Sugano D Blockus B Brabson J Brom C Jung H Ogren HW Paik DR Rust C Akerlof J Chapman D Errede MT Ken DI Meyer D Nitz R Thun R Tschirhart B Cork 《Canadian Metallurgical Quarterly》1987,35(7):2269-2271
27.
The implementation of an interactive approach to the display and manipulation of power system harmonics is described. The resulting microcomputer program, which was developed primarily for educational use within the electrical engineering curriculum, allows both synthesis of waves from harmonic (sinusoidal) components and analysis of specified periodic waveforms in terms of their harmonic content. Data may be interactively modified, and cases may be stored for later retrieval. Some of the means employed for making such a program user-friendly and student-oriented, as well as several examples of program use, are cited 相似文献
28.
Nymphs of the western drywood termite,Incisitermes minor (Hagen), were tested for their feeding preferences on wood and extracts of 11 tree species. The amount of wood consumed was inversely proportional to its specific gravity, but methanol extracts of least preferred woods were also least preferred when termites were confined to paper treated with extracts. In choice tests, only paper treated with extract of wood from which the colony developed and untreated and methanol-treated controls were significantly fed upon. Ponderosa pine extract applied to Douglas fir and sugar pine significantly decreased the amount of wood consumed. Resistance to termite feeding appeared to depend on the presence of repellent chemicals in the wood. 相似文献
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