6,363 research outputs found
Photoinitiated oxidative addition of CF3I to gold(I) and facile aryl-CF3 reductive elimination.
Herein we report the mechanism of oxidative addition of CF3I to Au(I), and remarkably fast Caryl-CF3 bond reductive elimination from Au(III) cations. CF3I undergoes a fast, formal oxidative addition to R3PAuR (R = Cy, R = 3,5-F2-C6H4, 4-F-C6H4, C6H5, 4-Me-C6H4, 4-MeO-C6H4, Me; R = Ph, R = 4-F-C6H4, 4-Me-C6H4). When R = aryl, complexes of the type R3PAu(aryl)(CF3)I can be isolated and characterized. Mechanistic studies suggest that near-ultraviolet light (λmax = 313 nm) photoinitiates a radical chain reaction by exciting CF3I. Complexes supported by PPh3 undergo reversible phosphine dissociation at 110 °C to generate a three-coordinate intermediate that undergoes slow reductive elimination. These processes are quantitative and heavily favor Caryl-I reductive elimination over Caryl-CF3 reductive elimination. Silver-mediated halide abstraction from all complexes of the type R3PAu(aryl)(CF3)I results in quantitative formation of Ar-CF3 in less than 1 min at temperatures as low as -10 °C
Sliding mode predictive control for chemical proces with time delay
16th IFAC World Congress Praga (República Checa), 03/07/2005A design of a novel model predictive controller is presented. The proposed Sliding Mode Predictive Control (SMPC) algorithm combines the design technique of Sliding-Mode Control (SMC) with Model based Predictive Control (MPC). The SMPC showed a considerable robustness improvement with respect to MPC in the presence of time delay, and showed an enhanced ability to handle set point changes in a nonlinear process. Its robustness was evaluated using a robustness plot, its performance was judged using a single input single output nonlinear mixing tank process with variable time delay
A comparison of a class of earth-moon orbits with a class of rotating Kepler orbits
Comparison of class of orbits in Earth-Moon field and class of Kepler orbits in rotating coordinates by use of concurrent series of graph
Fission yeast SWI/SNF and RSC complexes show compositional and functional differences from budding yeast.
SWI/SNF chromatin-remodeling complexes have crucial roles in transcription and other chromatin-related processes. The analysis of the two members of this class in Saccharomyces cerevisiae, SWI/SNF and RSC, has heavily contributed to our understanding of these complexes. To understand the in vivo functions of SWI/SNF and RSC in an evolutionarily distant organism, we have characterized these complexes in Schizosaccharomyces pombe. Although core components are conserved between the two yeasts, the compositions of S. pombe SWI/SNF and RSC differ from their S. cerevisiae counterparts and in some ways are more similar to metazoan complexes. Furthermore, several of the conserved proteins, including actin-like proteins, are markedly different between the two yeasts with respect to their requirement for viability. Finally, phenotypic and microarray analyses identified widespread requirements for SWI/SNF and RSC on transcription including strong evidence that SWI/SNF directly represses iron-transport genes
An Educational plant based on the Quadruple-tank process
7TH IFAC SYMPOSIUM ON ADVANCES IN CONTROL. 21/06/2006. MADRIDThis paper presents an experimental tank system developed at the University ofSeville for process control education. This plant is based on the well known quadruple-tank process and some modifications have been done in order to obtain a wide rangeof applications. The quadruple tank process is a multivariable laboratory plant of inter-connected tanks that can be easily configured to exhibit the effect of multivariable zero(minimum and non-minimum phase) on the system behavior, as well as the effect of nonlinear dynamics, saturation, constraints, etc.In the real plant implementation, the original structure of the process has been modifiedto offer a wide variety of uses for both educational and research purposes.Thus, differentplants can be configured such as one single tank, two or three cascaded tanks, a mixtureprocess and hybrid dynamics. Moreover the dynamics parameters of each tank can be setup by tuning the cross-section of the outlet hole of the tank. Furthermore, the real plant hasbeen implemented using industrial instrumentation and a PLC for the low level control.Supervision and control of the plant is carried out in a computer by means of OPC (Olefor Process Control) which allows one to connect the plant with a wide range of controlprograms such as LabView, Matlab or industrial SCADA.Ministerio de Ciencia y Tecnología DPI 2004-0744
Robert H. Bates and Anne O. Kruger (Eds.). Political and Economic Interactions in Economic Policy Reform (Book Review)
This volume is a welcome attempt to combine extremely disparate regional literature on structural adjustment programs. The empirical research for the book was conducted in such a way as to generate truly economic hypotheses and conclusions. Bates and Krueger commissioned eight teams of researchers; each composed of at least one political scientist and an economist. The teams\u27 initial agenda was to unravel the puzzle of why good economics means bad politics in relation to these structural adjustment programs. To meet that end, the teams were asked to investigate three phases surrounding the adjustment programs: Informed by current theories of interest groups, rent extraction, and bureaucracies, these analysts explored the political and economic background of the period prior to the reform process itself, and the political and economic reactions to adjustment. Included in the volume are the standard cases of stabilization and adjustment (Ghana, Zambia, Brazil), yet case selection is varied, resulting in fascinating studies of Turkey, Ecuador, and Egypt. In considering these less studied countries, the volume adds a wealth of monographic data to its theoretical agenda
Characterization of lysozyme messenger and lysozyme synthesized in vitro
Journal ArticleIn vitro systems for protein systhesis have been in wide use for about 10 years. In most of the early work protein synthesis was measured by following the incorporation of radioactive amino acids into acid precipitable material. This test cannot distinguish between the synthesis of complete, active proteins and various sorts of aberrant products which might result from incorrect initiation, translation in the wrong reading frame, amino acid substitutions, improper termination, or other defects in the vitro translation
Racism, Genocide, and Mass Murder: Toward a Legal Theory about Group Deprivations
This Article is focused on a specific and important issue: the relationship of law to the social reality of group deprivations. From this primary issue, several important sub-issues are generated having a real and substantial impact upon the role of law in the management of group deprivations at every level of social organization (local, national, regional, and international). To focus on the social reality of group deprivations requires a critical starting point. This starting point is determining whether we are adequately describing or assaying the etiology of the human personality types and self-systems that are normally characterized by feelings, sentiments, and behaviors and which, in the context of group deprivations, are prejudice-prone and, in egregious circumstances, are the kinds of personalities that are central to the operations of the policies and practices of genocide. This Article seeks to provide insight into this process, and further suggests that an in-depth and realistic understanding of legal responses to these problems will contribute to the control, regulation, and eventual elimination of these problems. Our approach is to radically contextualize the social context that reproduces the anti-Semitic or otherwise prejudice-prone personality type. This Article essentially argues, that if we can provide a systematic, contextually-based, socially-constructed framework within which to understand the general conditions conducive to the reproduction of discrimination, prejudice, anti-Semitism, or the general outlook that seeks to depreciate and destroy “others”, we can provide a stronger scientific predicate from which to more carefully construct and evaluate the legal theories of racial discrimination, apartheid, and genocide. This kind of insight may demonstrate the links between these phenomena as they emerge from the larger social context of human relations. They may help us understand more adequately how we may modify our legal theories and strategies to place a greater emphasis on moderation and prevention, timing our critical interventions as lawyers to improve the human prospect, and minimizing the reproduction of the social dynamics of hate, prejudice, and extermination
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