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Crystals of ethyl p-chloro α-cyano-β-methyl-cis-cinnamate, C13H12NO2Cl, are orthorhombic, space group Pbcn, with eight molecules per unit cell, a = 17.31, b = 8.68 and c = 17.20 Å. The structure was solved by direct methods and refined subsequently by Fourier techniques. The benzene ring makes a dihedral angle of 60.0° with the ethylenic group. This suggests significant steric effects of the β-methyl group and of the carbonyl group on the orientation of the benzene ring. The conformation of the ethylene bond and the carbonyl group around the Cα? C bond is roughly cisoid and the angle of twist is 16.5°. Nearest-neighbour >C = C <groups make contact across a two-fold axis at a center-to-center distance of 4.33 Å.  相似文献   
3.
A novel phytoecdysteroid, vitexirone, has been isolated from a MeOH extract of the root bark of the East African medicinal plantVitex fisherii by recycling high-performance liquid chromatography on a semipreparative scale. In addition, three known phytoecdysteroids, 20-hydroxyecdysone, ajugasterone C, and turkesterone, also were isolated. The structure of vitexirone has been established spectroscopically. The position and stereochemistry of the 11--hydroxy group of ajugasterone C and vitexirone were confirmed by the1H-1H homonuclear COSY NMR data. These phytoecdysteroids disrupt the molting process of the pink bollwormPectinophora gossypiella.  相似文献   
4.
We investigated the risk factors of outsourced software development. Our first objective was to create empirically generated lists of risk factors for both domestically- and offshore-outsourced projects. Our second objective was to compare these two contexts: how do the risk factors change and which ones are most important in each. To address these objectives, we conducted two Delphi surveys to identify the important risk factors from a client perspective, in domestic and offshore settings. We qualitatively compared the results of the surveys to identify similarities and differences across their risk profiles. We identified three types of risks: those that appeared in both contexts; those that appeared in both but were exacerbated in the offshore context; and those that were unique to the offshore context. Our findings suggested that traditional project management risks were important in both contexts; however, the offshore context seemed to be more vulnerable to some traditional risks as well as factors that were unique to it.  相似文献   
5.
Summary Efficient algorithms for computing the longest common subsequence (LCS for short) are discussed. O(pn) algorithm and O(p(m-p) log n) algorithm [Hirschberg 1977] seem to be best among previously known algorithms, where p is the length of an LCS and m and n are the lengths of given two strings (mn). There are many applications where the expected length of an LCS is close to m.In this paper, O(n(m-p)) algorithm is presented. When p is close to m (in other words, two given strings are similar), the algorithm presented here runs much faster than previously known algorithms.  相似文献   
6.
Mesarch MB  Nakatsu CH  Nies L 《Water research》2004,38(5):1281-1288
The objective of this work was to test a molecular genetic method for in situ monitoring of aerobic benzene, toluene, and xylene (BTX) biodegrading microorganisms. Catechol 2,3-dioxygenase (C23DO) genes occur in bacteria that biodegrade benzene, toluene, xylenes, phenol, biphenyl, and naphthalene. A competitive quantitative polymerase chain reaction (QC-PCR) technique using a single set of primers specific for an entire subfamily of C23DO genes was recently developed. To determine whether bacteria containing these C23DO genes actually exist in environments contaminated by BTX, aerobic microcosms containing previously uncontaminated soil were amended with different aromatic hydrocarbons and DNA extracts were analyzed by QC-PCR for C23DO genes. Anaerobic microcosms were established to confirm that oxygen was also necessary for the enrichment of C23DO genes. Field testing was done at two sites undergoing monitored natural attenuation. In microcosm experiments naphthalene, m-xylene, and p-xylene strongly enriched for C23DO genes while benzene, toluene, and o-xylene produced only transient, weakly detectable genes. In the field study, C23DO genes were detected in groundwater samples contaminated with either xylenes or naphthalene. The results of this study demonstrated that molecular genetic techniques can provide an accurate and rapid method to detect microorganisms capable of aromatic hydrocarbon biodegradation. Such a technique would be useful for monitoring the effectiveness of aeration technologies and for documenting microbial processes for monitored natural attenuation.  相似文献   
7.
Sociodemographic differences between rural and urban clients with severe mental illness (SMI) are explored using approaches which extend research in this area beyond limitations found in the few existing studies. Sixteen hundred adult clients from 18 Wisconsin counties are classified according to the degree of rurality of their counties of residence, using two definitions: a dichotomous metropolitan-non-metropolitan grouping and population density. There are significant differences between rural and urban clients for age, gender, and marital status, but not education or income. Young (18-35 years), unmarried males are more likely to live in more densely populated counties. Older (65 and older) women who are currently or previously married are more likely to live in less densely populated counties.  相似文献   
8.

This research empirically investigates the design choices that can be made to facilitate problem solving when intelligent systems fail. One way is to provide deep explanations, which are explanations that justify system actions. Another way is to manipulate system restrictiveness of the user interface. An experiment was conducted to investigate the effectiveness of deep explanation support, as well as manipulations of system restrictiveness. Results suggest that the less restrictive system was more effective for problem‐solving situations where system failure occurred. In addition, deep explanations were found to be somewhat helpful in system understanding, and this, in turn, led to improved problem‐solving performance.  相似文献   
9.
The virtual metamorphosis system lets people change their forms into any other form in a virtual scene. To realize these changes, a computer vision system estimates facial expressions and body postures and reproduces them in a computer graphics avatar in real time. We introduce three systems in order of their development: the Virtual Kabuki system, Networked Theater and “Shall We Dance?”  相似文献   
10.
A 54-year-old woman was admitted to our hospital because of a heart murmur without subjective symptoms. Angiography disclosed an enlarged right coronary artery and flow drainage into the left ventricle, ie, a large right coronary artery-left ventricle fistula. Analysis of pulsed Doppler studies and cineangiograms indicated considerable capacitance of this fistula owing to Windkessel action, which attenuated volume overload on the left ventricle. The features in this case suggest that evaluation of fistula hemodynamics is important in determining the overload on the ventricle through the fistula.  相似文献   
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