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General Treatment (general + treatment)
Selected AbstractsCHAPTER 17: General treatment of pneumoniaRESPIROLOGY, Issue S3 2006The committee for The Japanese Respiratory Society guidelines for the management of respiratory infections No abstract is available for this article. [source] Chemical reactions in the gas phase and in condensed matter: From wavefunctions to density operatorsINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 13 2009David A. Micha Abstract This contribution generalizes the treatment of chemical reactions in the gas phase based on the reaction channel decomposition of the wavefunction, by introducing a similar channel decomposition of the statistical density operator valid also for condensed phases such as liquid solutions and solid surfaces. Coupled equations for the channel components of the density operator are derived and a brief presentation is given of their partial Wigner transform, which leads to a general treatment for coupling quantum and classical variables. This provides a general approach for reactions involving electronically excited states in many-atom systems. It is pointed out that reactions involving coupled quantal and classical variables can be correctly described provided (a) initial conditions for trajectories are generated from quantal distributions and (b) the bundle of trajectories for the whole initial classical phase space is propagated coupled to the quantal elements of the density matrix and used in the calculation of reaction flux averages. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009 [source] Electron correlation: The many-body problem at the heart of chemistryJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 8 2007David P. Tew Abstract The physical interactions among electrons and nuclei, responsible for the chemistry of atoms and molecules, is well described by quantum mechanics and chemistry is therefore fully described by the solutions of the Schrödinger equation. In all but the simplest systems we must be content with approximate solutions, the principal difficulty being the treatment of the correlation between the motions of the many electrons, arising from their mutual repulsion. This article aims to provide a clear understanding of the physical concept of electron correlation and the modern methods used for its approximation. Using helium as a simple case study and beginning with an uncorrelated orbital picture of electronic motion, we first introduce Fermi correlation, arising from the symmetry requirements of the exact wave function, and then consider the Coulomb correlation arising from the mutual Coulomb repulsion between the electrons. Finally, we briefly discuss the general treatment of electron correlation in modern electronic-structure theory, focussing on the Hartree-Fock and coupled-cluster methods and addressing static and dynamical Coulomb correlation. © 2007 Wiley Periodicals, Inc. J Comput Chem 28: 1307,1320, 2007 [source] Generalized least-squares parameter estimation from multiequation implicit modelsAICHE JOURNAL, Issue 10 2003Simon L. Marshall Maximum likelihood fit of nonlinear, implicit, multiple-response models to data containing normally distributed random errors can be carried out by a combination of the Gauss-Newton generalized nonlinear least-square algorithm first described by Britt and Luecke in 1973, with a Fletcher-Reeves conjugate gradient search for initial parameter estimates. The convergence of the algorithm is further improved by adding a step-limiting procedure that ensures a reduction in the objective function for each iteration. Multiple-equation regression methods appropriate to the solution of explicit fixed-regressor models are derived from this general treatment as special cases. These include weighted nonlinear least squares (where the covariance matrix of the response is known), and uniformly weighted nonlinear least squares (where the responses are uncorrelated and characterized by a single common variance). Alternative methods for fixed-regressor fits of explicit multiequation models with an unknown covariance matrix of the responses are also considered. The moment-matrix determinant criterion appropriate in such situations is also efficiently minimized by use of the conjugate-gradient algorithm, which is considerably less sensitive to the accuracy of the initial parameter estimate than the more usual Gauss-Newton methods. The performance of the new algorithm for models defined by one, two, and three implicit functional constraints per point is illustrated by random-regressor fits of isothermal p,X and p,X,Y vapor,liquid equilibrium data, and ternary liquid,liquid equilibrium data, respectively. [source] Bacterial vaginosis Transmission, role in genital tract infection and pregnancy outcome: an enigma,APMIS, Issue 4 2005Review article III Whether bacterial vaginosis (BV) is acquired from an endogenous or an exogenous source is subject to controversy. Despite findings of an association between sexual behaviour and BV, some data indicate that BV is not a sexually transmitted infection in the traditional sense, while other data indicate that BV is an exogenous infection. A third aspect of BV is its tendency to go unnoticed by affected women. All of this will have a strong impact on how physicians view the risks of asymptomatic BV. This review focuses on whether or not BV should be regarded as a sexually transmitted infection (STI), its role in postoperative infections and pelvic inflammatory disease (PID), and on whether or not treatment of BV during pregnancy to reduce preterm delivery should be recommended. The reviewed studies do not lend unequivocal support to an endogenous or exogenous transmission of the bacteria present in BV. For women undergoing gynaecological surgery such as therapeutic abortion, the relative risk of postoperative infection is clearly elevated (approx. 2.3,2.8). A weaker association exists between BV and pelvic inflammatory disease. Data on treatment of BV as a way of reducing preterm delivery are inconclusive and do not support recommendations for general treatment of BV during pregnancy. The discrepant associations between BV and preterm birth found in recent studies may be explained by variations in immunological response to BV. Genetic polymorphism in the cytokine response , both regarding the TNF alleles and in interleukin production , could make women more or less susceptible to BV, causing different risks of preterm birth. Thus, studies on the vaginal inflammatory response to microbial colonization should be given priority. [source] On QoS mechanism profiling in MPLS-TP transport networksBELL LABS TECHNICAL JOURNAL, Issue 4 2010Christian Addeo In the context of packet management in optical transport networks, quality of service (QoS) is playing an important role to achieve the right levels of bandwidth, latency, and general treatment for the different services carried over the network. The scope of this paper is to describe quality of service functionalities in the context of a packet transport network. This paper refers to the definition and implementation of the quality of service model in a packet transport network node, describing how this information is carried over a packet transport network. The Alcatel-Lucent 1850 Transport Service Switch (TSS) platform serves as our reference point for a packet transport node. We also include a description of classification, policing, marking, and, in particular, hierarchical scheduling and shaping. © 2010 Alcatel-Lucent. [source] The Politics of Childhood and Asylum in the UKCHILDREN & SOCIETY, Issue 4 2007Clotilde Giner This article considers the general treatment of asylum-seeking families with children in the UK, focusing on the government's practices and public reactions to these measures. It first describes both the exclusive asylum framework, based on institutionalised suspicion, welfare restrictions and detention, and the inclusive child policy framework, based on recognising children's rights and protecting all children. The article then investigates the implications for policy-making that these radically opposed regimes have for those who fall between the two categories, i.e. asylum-seeking children. To this end, we examine more closely three asylum practices , Section 9 of the Asylum and Immigration (Treatment of Claimants, etc.) Act 2004, detention of accompanied asylum-seeking children in immigration removal centres and removals. Our analysis indicates that the government's attempt to fully include families within the restrictive asylum framework has been somewhat frustrated by the mobilisation of a wide range of public actors. As such, despite its supposedly ,legally unconstrained' room for action, the government has recently agreed to partly review its policy standards for asylum-seeking families, apparently aware of the potentially damaging effects of being seen as disregarding children's rights and needs. On the other hand, the government does not seem inclined to question the current asylum framework and the assumptions on which it is based. Consequently, the asylum system for families is likely to remain based on ad hocarrangements conditioned by the scale of the protests. [source] Structural determinations by circular dichroism spectra analysis using coupled oscillator methods: An update of the applications of the DeVoe polarizability model,CHIRALITY, Issue 7 2004Stefano Superchi Abstract The exciton (coupled oscillator) model for optical activity is a very useful and powerful method which allows to analyze a circular dichroism (CD) spectrum in a nonempirical way, arriving at a safe assignment of the absolute configuration of organic and inorganic compounds. Usually in this model only the exciton coupling of two electrically allowed transitions (oscillators) is taken into account. This approach has the important advantage of an easy application but, sometimes, it may lead to wrong results. Thus, in this review article a more general treatment, which allows considering the simultaneous coupling of several oscillators, i.e., the DeVoe model, is presented and critically analyzed, discussing in detail the latest applications reported in the literature. In the authors opinion, since the DeVoe model joins generality and reliability requiring an almost negligible computational effort, it represents the method of choice for stereochemical assignments, even by nonspecialists. Chirality 16:422,451, 2004. © 2004 Wiley-Liss, Inc. [source] | |||||||||||||