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11.
P. E. A. Teal R. R. Heath J. H. Tumlinson J. R. McLaughlin 《Journal of chemical ecology》1981,7(6):1011-1022
Eight compounds were isolated from the sex pheromone gland ofHeliothis subflexa (Gn.) and identified as hexadecanal, (Z)-9-hexadecenal, (Z)-11-hexadecenal, (Z)-7-hexadecen-1-ol acetate, (Z)-9-hexadecen-1-ol acetate, (Z)-11-hexadecen-1-ol acetate, (Z)-9-hexadecen-1-ol, and (Z)-11-hexadecen-1-ol. Although the whole blend was found to be an effective male attractant, the deletion of alcohols from the blend increased trap captures considerably. Further, although the binary mixture of (Z)-9-hexadecenal and (Z)-11-hexadecenal caught some maleH. subflexa, significant increases in captures were noted when the three acetate components were included in the blend.Mention of a commercial or proprietary product in this paper does not constitute an endorsement of that product by the USDA or the State of Florida. 相似文献
12.
Sorting by Short Block-Moves 总被引:1,自引:0,他引:1
Sorting permutations by operations such as reversals and block-moves has received much interest because of its applications
in the study of genome rearrangements and in the design of interconnection networks. A short block-move is an operation on
a permutation that moves an element at most two positions away from its original position. This paper investigates the problem
of finding a minimum-length sorting sequence of short block-moves for a given permutation. A 4/3 -approximation algorithm
for this problem is presented. Woven double-strip permutations are defined and a polynomial-time algorithm for this class
of permutations is devised that employs graph matching techniques. A linear-time maximum matching algorithm for a special
class of grid graphs improves the time complexity of the algorithm for woven double-strip permutations.
Received June 1, 1997; revised July 25, 1998. 相似文献
13.
Development of Habitat Suitability Criteria and In‐Stream Habitat Assessment for the Benthic Cyanobacteria Phormidium 下载免费PDF全文
Global demand for freshwater has led to unprecedented levels of water abstraction from riverine systems. This has resulted in large alterations in natural river flows. The deleterious impacts of reduced flows on fish and macroinvertebrate abundances have been thoroughly investigated; in contrast, there is a limited understanding of the potential for changes in the abundance of nuisance benthic algal/cyanobacterial blooms. In New Zealand, Phormidium sp. blooms are common in numerous rivers during summer low flows. In this study, an in‐stream habitat assessment is used to examine the relationship between Phormidium habitat availability and reducing flows. Over 650 observations of Phormidium mats, from seven sites (Hutt River, lower North Island, New Zealand), were used to construct habitat suitability curves for depth, velocity and substrate. Preference curves were fitted using both the ‘forage ratio’ and ‘quantile regression’ methods. Phormidium growth, observed at all seven sites, increased significantly from upstream (uppermost site, 5.2% mat cover) to downstream (63.5%). The habitat suitability curves revealed Phormidium had a large tolerance to velocity, depth and substrate type. Consequently, decreases in flow had only negligible effects on available Phormidium habitat. During periods of stable flow, Phormidium abundance positively correlated with increased nitrogen concentrations, potentially explaining the large variation in Phormidium cover from upstream to downstream. Quantile regression generated habitat suitability criteria were a more accurate predictor of available Phormidium habitat than the forage ratio criteria. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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Transmit selection in spatial multiplexing systems 总被引:3,自引:0,他引:3
In this letter we solve the transmit antenna selection problem for a zero forcing spatial multiplexing system with knowledge of the channel statistics at the transmitter. We show through Wishart matrix analysis that the signal-to-noise ratio on the kth stream is a weighted Chi-squared variable with the weight equal to-the kth diagonal entry of the inverted transmit correlation matrix. We use this result to develop selection algorithms for two cases-maximizing ergodic capacity and minimizing the average probability of error. Monte Carlo simulations illustrate potential performance improvements. 相似文献
16.
Kosjek T Perko S Zupanc M Zanoški Hren M Landeka Dragičević T Zigon D Kompare B Heath E 《Water research》2012,46(2):355-368
Benzodiazepine derivatives are prescribed in large quantities globally and are potentially new emerging environmental contaminants. Unfortunately, a dearth of data exists concerning occurrence, persistence and fate in the environment. This paper redresses this by reviewing existing literature, assessing the occurrence of selected benzodiazepine anxiolytics (diazepam, oxazepam and bromazepam) in wastewater influent and effluent and surface water from Slovenia, evaluating their removal during water treatment and identifying the transformation products formed during water treatment. Their occurrence was monitored in hospital effluent, river water and in wastewater treatment plant influent and effluent. The study reveals the presence of benzodiazepine derivatives in all samples with the highest amounts in hospital effluents: 111 ng L−1, 158 ng L−1 and 72 ng L−1 for diazepam, bromazepam and oxazepam, respectively. Removal efficiencies with respect to biological treatment of diazepam were 16-18% (oxic), 18-32% (anoxic → oxic), 53-76% (oxic → anoxic) and 83% (oxic → anoxic → oxic → anoxic cascade bioreactors), while the removal oxazepam was 20-24% under anoxic conditions. Coupled biological and photochemical treatment followed by the adsorption to activated carbon resulted in a removal efficiency of 99.99%. Results reveal the recalcitrant nature of benzodiazepine derivatives and suggest that only combinational treatment is sufficient to remove them. In addition, eight novel diazepam and four novel oxazepam transformation products are reported. 相似文献
17.
D'Onofrio Brian M.; Turkheimer Eric; Emery Robert E.; Slutske Wendy S.; Heath Andrew C.; Madden Pamela A.; Martin Nicholas G. 《Canadian Metallurgical Quarterly》2006,42(3):486
Parental divorce is associated with problematic offspring adjustment, but the relation may be due to shared genetic or environmental factors. One way to test for these confounds is to study offspring of twins discordant for divorce. The current analyses used this design to separate the mechanisms responsible for the association between parental divorce, experienced either before or after the age of 16, and offspring well-being. The results were consistent with a causal role of divorce in earlier initiation of sexual intercourse and emotional difficulties, in addition to a greater probability of educational problems, depressed mood, and suicidal ideation. In contrast, the increased risk for cohabitation and earlier initiation of drug use was explained by selection factors, including genetic confounds. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
18.
What is the value of limited feedback for MIMO channels? 总被引:7,自引:0,他引:7
Feedback in a communications system can enable the transmitter to exploit channel conditions and avoid interference. In the case of a multiple-input multiple-output channel, feedback can be used to specify a precoding matrix at the transmitter, which activates the strongest channel modes. In situations where the feedback is severely limited, important issues are how to quantize the information needed at the transmitter and how much improvement in associated performance can be obtained as a function of the amount of feedback available. We give an overview of some recent work in this area. Methods are presented for constructing a set of possible precoding matrices, from which a particular choice can be relayed to the transmitter. Performance results show that even a few bits of feedback can provide performance close to that with full channel knowledge at the transmitter. 相似文献
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20.
Shorelines of Lake Algonquin, the largest of the glacial lakes of the Great Lakes area, are well known in southern Ontario, but are sporadic and difficult to trace northward onto the Precambrian shield. Improved knowledge of the extent and uplift pattern for Algonquin shorelines is needed to support geophysical models of isostatic response, interpretation of glacial and glacial lake history, and the search by archeologists for evidence of Paleoindian activity, shown to be localized along its shoreline. The Sudbury basin is one of the few areas of mapping of Quaternary geology on the Canadian shield that provides a record of Algonquin lake phases. Meltwaters from the northward-receding ice front formed a series of deltas southward into the Sudbury basin in central Ontario around the time the Cartier I moraine was deposited. Instrumental surveys of deltas, bars, and shorebluffs carried out in the northern Sudbury basin delineate several discrete water planes. Correlation with previously surveyed and correlated shorelines on Manitoulin Island, southwest of Sudbury, indicates the presence of an upper Algonquin shoreline and features correlated to the Cedar Point, Payette, Sheguiandah, and Korah levels. Features southwest of the Sudbury basin at Nairn correlate with Korah and post-Korah water levels. Land between Nairn and Sudbury is too elevated to have been reached by the later Nipissing transgression. Similar shoreline sequences have been surveyed near North Bay, with results supporting the findings of this study. 相似文献