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161.
Stress-relaxation curves were obtained for ionomers containing different cations, per cents of ionization, and thermal treatments. Differences in the rheological behavior were found to depend more on the ionization level than on the ion. A recently proposed model for ionomers is discussed and found to be consistent with these results. In terms of this model the degree of ionization in the polymer acts as a regulator for the growth of small oriented lamellar (crystalline) regions. In the most general terms, the mechanical behavior and strength of ionomers appears dominated by the existence of “hard” regions interspersed among “soft” regions. In the polymers studied here there was some slight crystallinity; however, similar effects and explanations are probably suitable for amorphous “ionomers.” Toughness was also found in some completely amorphous carboxylcontaining copolymers without added ionic salts. The same explanation of “hard” regions interspersed among soft regions is also valid here. The “blocky” nature of the copolymerization may play a role in setting up this type of structure. 相似文献
162.
Mandeep M. Sahani Tarek M. Daoud Ramin Sam Jerry Andrews Yuk Lun Cheng Carl M. Kjellstrand Todd S. Ing 《Hemodialysis international. International Symposium on Home Hemodialysis》2001,5(1):92-96
An aggressive dialysis in a grossly azotemic patient, especially one with severe metabolic acidosis, can lead to dialysis disequilibrium syndrome (DDS). Mild forms present as nausea, vomiting, restlessness, and headache. Severe manifestations include seizures, obtundation, coma, and even death. This clinical picture is caused by cerebral edema induced by one or more of the following mechanisms:
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163.
Sequestration of Host Plant Glucosinolates in the Defensive Hemolymph of the Sawfly Athalia rosae 总被引:1,自引:1,他引:0
Caroline Müller Niels Agerbirk Carl Erik Olsen Jean-Luc Boevé Urs Schaffner Paul M. Brakefield 《Journal of chemical ecology》2001,27(12):2505-2516
Interactions between insects and glucosinolate-containing plant species have been investigated for a long time. Although the glucosinolate–myrosinase system is believed to act as a defense mechanism against generalist herbivores and fungi, several specialist insects use these secondary metabolites for host plant finding and acceptance and can handle them physiologically. However, sequestration of glucosinolates in specialist herbivores has been less well studied. Larvae of the turnip sawfly Athalia rosae feed on several glucosinolate-containing plant species. When larvae are disturbed by antagonists, they release one or more small droplets of hemolymph from their integument. This reflex bleeding is used as a defense mechanism. Specific glucosinolate analysis, by conversion to desulfoglucosinolates and analysis of these by high-performance liquid chromatography coupled to diode array UV spectroscopy and mass spectrometry, revealed that larvae incorporate and concentrate the plant's characteristic glucosinolates from their hosts. Extracts of larvae that were reared on Sinapis alba contained sinalbin, even when the larvae were first starved for 22 hr and, thus, had empty guts. Hemolymph was analyzed from larvae that were reared on either S. alba, Brassica nigra, or Barbarea stricta. Leaves were analyzed from the same plants the larvae had fed on. Sinalbin (from S. alba), sinigrin (B. nigra), or glucobarbarin and glucobrassicin (B. stricta) were present in leaves in concentrations less than 1 mol/g fresh weight, while the same glucosinolates could be detected in the larvae's hemolymph in concentrations between 10 and 31 mol/g fresh weight, except that glucobrassicin was present only as a trace. In larval feces, only trace amounts of glucosinolates (sinalbin and sinigrin) could be detected. The glucosinolates were likewise found in freshly emerged adults, showing that the sequestered phytochemicals were transferred through the pupal stage. 相似文献
164.
Bidell Markus P.; Ragen Julia K.; Broach Carl D.; Carrillo Elizabeth A. 《Canadian Metallurgical Quarterly》2007,1(3):204
With the ascension of the Internet as an information resource, Web sites are likely to be the first exposure applicants have to specific programs. The authors evaluated professional psychology program Web sites for ethnic and sexual orientation minority content, discovering that diversity content of Web sites was considerably less than in previously examined paper application materials. Clinical psychology programs were more likely to state a commitment to diversity training while counseling psychology programs were more likely to state a diversity minor/track. School psychology programs had the lowest diversity content on their Web pages. This article explores how graduate psychology program Web sites communicate multicultural information and offers recommendations on using the World Wide Web as a cost-effective tool to attract a diverse student body. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
165.
Carl Vondrick Donald Patterson Deva Ramanan 《International Journal of Computer Vision》2013,101(1):184-204
We present an extensive three year study on economically annotating video with crowdsourced marketplaces. Our public framework has annotated thousands of real world videos, including massive data sets unprecedented for their size, complexity, and cost. To accomplish this, we designed a state-of-the-art video annotation user interface and demonstrate that, despite common intuition, many contemporary interfaces are sub-optimal. We present several user studies that evaluate different aspects of our system and demonstrate that minimizing the cognitive load of the user is crucial when designing an annotation platform. We then deploy this interface on Amazon Mechanical Turk and discover expert and talented workers who are capable of annotating difficult videos with dense and closely cropped labels. We argue that video annotation requires specialized skill; most workers are poor annotators, mandating robust quality control protocols. We show that traditional crowdsourced micro-tasks are not suitable for video annotation and instead demonstrate that deploying time-consuming macro-tasks on MTurk is effective. Finally, we show that by extracting pixel-based features from manually labeled key frames, we are able to leverage more sophisticated interpolation strategies to maximize performance given a fixed budget. We validate the power of our framework on difficult, real-world data sets and we demonstrate an inherent trade-off between the mix of human and cloud computing used vs. the accuracy and cost of the labeling. We further introduce a novel, cost-based evaluation criteria that compares vision algorithms by the budget required to achieve an acceptable performance. We hope our findings will spur innovation in the creation of massive labeled video data sets and enable novel data-driven computer vision applications. 相似文献
166.
Amr Nagaty Sajad Saeedi Carl Thibault Mae Seto Howard Li 《Journal of Intelligent and Robotic Systems》2013,70(1-4):1-12
This paper presents the development of a nonlinear quadrotor simulation framework together with a nonlinear controller. The quadrotor stabilization and navigation problems are tackled using a nested loops control architecture. A nonlinear Backstepping controller is implemented for the inner stabilization loop. It asymptotically tracks reference attitude, altitude and heading trajectories. The outer loop controller generates the reference trajectories for the inner loop controller to reach the desired waypoint. To ensure boundedness of the reference trajectories, a PD controller with a saturation function is used for the outer loop. Due to the complexity involved in controller development and testing, a simulation framework has been developed. It is based on the Gazebo 3D robotics simulator and the Open Dynamics Engine (ODE) library. The framework can effectively facilitate the development and validation of controllers. It has been released and is available at Gazebo quadrotor simulator (2012). 相似文献
167.
Gold (1967) discovered a fundamental enumeration technique, the socalled identification-by-enumeration, a simple but powerful class of algorithms for learning from examples (inductive inference). We introduce a variety of more sophisticated (and more powerful) enumeration techniques and characterize their power. We conclude with the thesis that enumeration techniques are even universal in that each solvable learning problem in inductive inference can be solved by an adequate enumeration technique. This thesis is technically motivated and discussed. 相似文献
168.
Xiaoping Wang Hsiang-te Kung Verner Carl Johnson Aamir Latif 《International journal of remote sensing》2013,34(3):953-973
ABSTRACTThe remote sensing information on the extraction method is of great importance to improve the accuracy and efficiency of soil salinization information. The objective of this study is to develop remote sensing extraction techniques to improve soil salinization maps. The following procedures were used in this study: (1) developed a fractional-order algorithm-based methodology of filter from high-resolution remote sensing imagery (Sentinel-2 MSI); (2) investigated the changing trend of image under different order filters; and (3) used a grid-search algorithm-support vector machines (GS-SVM) classification to employ extraction information of soil salinization. The results showed that the Fractional-order filter method outperformed the integer derivative in extracted information of soil salinization. In comparison of the classification accuracy between fractional-order processing algorithm and integer-order image processing algorithm, the fractional order has improved remarkably. The optimal classification model was 0.6 order, 0.8 order, 1.4 order, 1.6 order, and 1.8 order models. The overall accuracy and kappa coefficient (κ) of these models are 91.90% and 0.90, respectively. Analysing and comparing between soil salt index and filtering algorithm (1.2 order), the researchers found that the classification results of the two methods are similar. In general, this method can successfully extract soil salinization information in dry regions. 相似文献
169.
This work provides one of the first attempts to derive computationally tractable criteria for analysing the stability of linear parameter varying (LPV) time-delayed systems. We present both delay-independent and delay-dependent stability conditions, which are derived using appropriately selected Lyapunov-Krasovskii functionals. According to the system parameter dependence, these functionals can be selected to obtain increasingly non-conservative results. Gridding techniques may be used to cast these tests as linear matrix inequalities (LMIs). In cases when the system matrices depend affinely or quadratically on the parameter, gridding may be avoided. These LMIs can be solved efficiently using available software. A numerical example of a time-delayed system motivated by a metal removal process is used to demonstrate the theoretical results. 相似文献
170.
Carl C. Williams 《Information Systems Management》2013,30(3):81-84
Managing a diverse assemblage of hardware and software has become a costly problem for many organizations. Careful desktop asset management can radically reduce operational costs and free up scarce dollars for more pressing IS needs. 相似文献