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Specific Mode (specific + mode)
Selected AbstractsProbabilistic Approach for Nonlinear Modal Control of MDOF Structures Subjected to Multiple ExcitationsCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 1 2005Kyung-Won Min For the modal control of the MDOF structure, a new eigenvalue assignment algorithm that modifies the dynamic characteristics of only the specific mode is proposed. For the probabilistic evaluation of the proposed nonlinear modal control, the joint probability density function (PDF) of the equivalent nonlinearly controlled single-degree-of-freedom (SDOF) system is obtained by the solution of the reduced Fokker,Planck equation for the equivalent nonlinear system. To overcome the difficulty in the application of the joint PDF to the MDOF structure controlled by the hybrid mass damper (HMD) system and subjected to multiple excitations, the equivalent damping ratio is proposed. The results of the analysis indicate that the proposed nonlinear modal control strategy is effective for the control of MDOF structures requiring a significantly smaller peak control force than the linear quadratic Gaussian (LQG) controller to produce a similar control performance level. [source] Possibilism: An Approach to Problem-Solving Derived from the Life and Work of Albert O. HirschmanDEVELOPMENT AND CHANGE, Issue 3 2008Philipp H. Lepenies ABSTRACT Albert O. Hirschman is the author of seminal, but prima facie unconnected contributions to the social sciences (,exit,voice', ,linkages'). Yet, his main originality lies in his general approach to problem-solving which is hidden behind the complexity of his oeuvre. This article intends to disentangle the intricacies of his work and to reveal his specific mode of investigation by making the multifaceted biographical influences on Hirschman's scholarly writings visible. Exhibiting the influence that decisive moments in his life had on his work not only allows us to identify and define his method of ,possibilism': it also shows that this approach remains a valid and useful multidisciplinary tool for unorthodox contemporary social analysis. [source] How virtual are we?INFORMATION SYSTEMS JOURNAL, Issue 4 2005Measuring virtuality, understanding its impact in a global organization Abstract., Employees in global corporations are increasingly involved in ,virtual teams' on a regular basis. Conflicting definitions of virtuality make it hard to measure such things as how much virtual teaming occurs and how virtual teaming affects performance. As a consequence, it is hard to allocate funding and to design infrastructures and software to support this specific mode of working. Using the concept of discontinuities, or changes in expected conditions, we propose a virtuality index to assess how ,virtual' a given setting is. The discontinuities used include geography, time zone, organization, national culture, work practices, and technology. The index separately measures these aspects of virtuality and their effect on perceived team performance. Data collected at a large multinational corporation clustered into three overarching discontinuities: team distribution, workplace mobility, and variety of work practices. The study revealed that being distributed in and of itself had no impact on self-assessed team performance. Work practice predictability and sociability mitigated effects of working in discontinuous environments, while variety of practices (cultural and work process diversity) and employee mobility negatively impacted performance. [source] Anisotropy of spin relaxation of water protons in cartilage and tendonNMR IN BIOMEDICINE, Issue 3 2010Konstantin I. Momot Abstract Transverse spin relaxation rates of water protons in articular cartilage and tendon depend on the orientation of the tissue relative to the applied static magnetic field. This complicates the interpretation of magnetic resonance images of these tissues. At the same time, relaxation data can provide information about their organisation and microstructure. We present a theoretical analysis of the anisotropy of spin relaxation of water protons observed in fully hydrated cartilage. We demonstrate that the anisotropy of transverse relaxation is due almost entirely to intramolecular dipolar coupling modulated by a specific mode of slow molecular motion: the diffusion of water molecules in the hydration shell of a collagen fibre around the fibre, such that the molecular director remains perpendicular to the fibre. The theoretical anisotropy arising from this mechanism follows the ,magic-angle' dependence observed in magnetic-resonance measurements of cartilage and tendon and is in good agreement with the available experimental results. We discuss the implications of the theoretical findings for MRI of ordered collagenous tissues. Copyright © 2009 John Wiley & Sons, Ltd. [source] Mobile loop mutations in an archaeal inositol monophosphatase: Modulating three-metal ion assisted catalysis and lithium inhibitionPROTEIN SCIENCE, Issue 2 2010Zheng Li Abstract The inositol monophosphatase (IMPase) enzyme from the hyperthermophilic archaeon Methanocaldococcus jannaschii requires Mg2+ for activity and binds three to four ions tightly in the absence of ligands: KD = 0.8 ,M for one ion with a KD of 38 ,M for the other Mg2+ ions. However, the enzyme requires 5,10 mM Mg2+ for optimum catalysis, suggesting substrate alters the metal ion affinity. In crystal structures of this archaeal IMPase with products, one of the three metal ions is coordinated by only one protein contact, Asp38. The importance of this and three other acidic residues in a mobile loop that approaches the active site was probed with mutational studies. Only D38A exhibited an increased kinetic KD for Mg2+; D26A, E39A, and E41A showed no significant change in the Mg2+ requirement for optimal activity. D38A also showed an increased Km, but little effect on kcat. This behavior is consistent with this side chain coordinating the third metal ion in the substrate complex, but with sufficient flexibility in the loop such that other acidic residues could position the Mg2+ in the active site in the absence of Asp38. While lithium ion inhibition of the archaeal IMPase is very poor (IC50,250 mM), the D38A enzyme has a dramatically enhanced sensitivity to Li+ with an IC50 of 12 mM. These results constitute additional evidence for three metal ion assisted catalysis with substrate and product binding reducing affinity of the third necessary metal ion. They also suggest a specific mode of action for lithium inhibition in the IMPase superfamily. [source] Unverzichtbar gegen Bakterien: Antibiotika.CHEMIE IN UNSERER ZEIT (CHIUZ), Issue 5 200980 Jahre Verwendung von Antibiotika in der Medizin Abstract Auch 80 Jahre nach der Entdeckung von Penicillin ist die Forschung nach neuen Antibiotika noch nicht abgeschlossen. Zunehmendes Auftreten von Resistenzen gegenüber den verwendeten Antibiotika erfordern einen verantwortungsvollen Einsatz bekannter Anibiotika und die Entwicklung verbesserter Medikamente. Mittlerweile existieren 8000 antibiotisch wirksame Substanzen, von denen ca. 100 in der Medizin angewandt werden. Trotzdem gibt es zahlreiche Infektionen, die nicht ausreichend behandelt werden können. Antibiotika werden in der Human- und Veterinärmedizin eingesetzt. Der bedenkliche Einsatz als Ergotropika, um die Infektionsraten von Masttieren zu vermindern und die Futterverwertung der Tiere zu steigern, konnte in den letzten Jahren zurückgedrängt werden. Die teils unsachgemäße Anwendung erzeugt einen selektiven Druck, der Resistenzen bei den Erregern hervorruft. Ihr bedrohlicher Einfluss auf die Therapie vor allem gramnegativer Bakterien könnten manche Teile der Welt in eine präantibiotische Ära zurückversetzen, da sich adäquate Therapiemöglichkeiten zunehmend verringern. Dies unterstreicht wiederum die Wichtigkeit neue Antibiotika bzw. neue Therapieansätze zu entwickeln. Ideen dazu gibt es genug. Eighty years after the recovery of Penicillin the search for new antibiotics is still ongoing. By now there exist 8000 effective antibiotics, from which 100 have medical applications. Nevertheless there exist a lot of infections, which cannot be sufficiently treated. New antibiotics should have a specific mode of function that differs from known antibiotics. Additionally they should avoid secondary effects on humans, have a good resorption and act at the right place in the body, without being immediately released. [source] Monitoring river sediments contaminated predominantly with polyaromatic hydrocarbons by chemical and in vitro bioassay techniquesENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 7 2001Jan Vondrá Abstract Extracts of sediment samples collected from the Morava River and its tributaries (Czech Republic) were examined for mutagenic, dioxin-like, and estrogenic activities. Moreover, the human leukemic HL-60 cell line was tested as a potential model for the detection of effects of environmental contaminants on cell proliferation and differentiation processes. Analytical data indicate that the sediments were contaminated predominantly with polycyclic aromatic hydrocarbons (PAHs) and phthalate esters. The sums of concentrations of 16 U.S. Environmental Protection Agency priority PAHs ranged from 0.8 to 13.2 ,g/g and those of phthalates reached up to 3,000 ng/g, while only low levels of chlorinated hydrocarbons were found. The main goal of the present study was to determine effects of PAH prevalence on in vitro bioassays, with special emphasis on dioxin-like activity. The dioxin-like activity was tested using a reporter gene assay based on chemical-activated luciferase expression (the CALUX assay). Significant dioxin-like activity (2.6,40.1 ,g/g benzo[a]pyrene equivalents and 5.9,48.2 ng/g 2,3,7,8-tetrachlorodibenzo- p -dioxin equivalents) was detected in all samples, and the results obtained with various exposure times or with both crude and PAH-deprived extracts indicate that the response was probably caused almost exclusively by the presence of high concentrations of PAHs. This corresponds with results of chemical analyses and indicates that various exposure times would allow a discrimination between dioxin-like activities of persistent compounds and easily metabolized aryl hydrocarbon (Ah) receptor inducers. Only sediment extracts containing the highest concentrations of PAHs were mutagenic, as determined by the umu assay. Estrogenic activity was found in several samples (4.75,22.61 pg/g estradiol equivalents) using cells stably transfected with an estrogen-responsive element linked to a luciferase promoter. Noncytotoxic doses of extracts had no effects on HL-60 cell proliferation, while two of the tested crude extracts significantly enhanced their all- trans retinoic acid-induced differentiation. These activities were not associated with phthalate esters and/or PAHs. Our results indicate that cellular and biochemical in vitro assays based on various specific modes of action may yield data complementary to results of mutagenicity tests and that they could be useful in environmental risk assessment. High levels of PAHs are apparently associated with dioxin-like and mutagenic activities rather than with estrogenic activity. [source] Party Competition and the Resilience of CorporatismGOVERNMENT AND OPPOSITION, Issue 2 2009Mette Anthonsen This article argues that after the Golden Age of capitalism, corporatist methods of policy-making have come to depend on specific modes of party competition. In contrast to previous studies of corporatism, which have argued that corporatism depends on strong social democratic parties, this article suggests that the competition between well-defined left-wing and right-wing ,blocs' has become detrimental to corporatism. In countries with mixed governments or traditions of power-sharing, on the other hand, corporatism thrives. These conclusions are based on a comparison of four traditionally corporatist countries , Denmark, the Netherlands, Sweden and Switzerland , from the early 1970s to the late 1990s. [source] "Where Are They Going?": Immigrant Inclusion in the Czech Republic (A Case Study on Ukrainians, Vietnamese, and Armenians in Prague),INTERNATIONAL MIGRATION, Issue 2 2007an Drbohlav ABSTRACT This paper is based on research conducted by the International Organization for Migration (IOM) Office in Prague and the Faculty of Science, Charles University in Prague in the fall and winter of 2003-2004. Within the questionnaire survey, 126 first-generation immigrants in Prague (51 Ukrainians, 45 Vietnamese, and 30 Armenians) were successfully contacted via a non-probability sampling method. The main goals of the research were to ascertain what mode of inclusion into Czech society the immigrant groups practiced and to determine their satisfaction level with their new lives. Special attention was paid to finding out important factors that stand behind both the common features and particular patterns of behaviour. Our approach is an attempt to analyse the issue via quantitative statistics (Chi-square Test, the AnswerTree Method). Berry's (1992) acculturation strategies model and Portes and Zhou's (e.g. 2000) segmented assimilation model serve as reference points while discussing conceptual matters. The results indicate that the immigrants' inclusion in Czech society in Prague has developed into specific modes: Ukrainians are typical of their specific transnationalization patterns, Vietnamese represent a "well-off" but separated and segregated community, and Armenians practice a clear assimilation strategy, while approaching the mainstream in terms of socio-economic status. Based on various indications, it seems that successful inclusion in Czech society is connected to the assimilation mode. In sum, the immigrants most satisfied with their quality of life are those for whom it is not important to live close to their compatriots and those whose knowledge of the spoken Czech language is above average. The lowest satisfaction score is tied to those immigrants who prefer to live close to their compatriots, those with university education, and those with a low income. Good knowledge of the Czech language seems to be a gateway to immigrants' satisfaction. Cette étude s'appuie sur un travail de recherche mené par le bureau de Prague de l'Organisation internationale pour les migrations (OIM) et la faculté des sciences de l'Université Charles à Prague, au cours de l'automne et de l'hiver 2003-2004. Dans le cadre de l'enquête-questionnaire, 126 immigrants de la première génération se trouvant à Prague (51 Ukrainiens, 45 Vietnamiens et 30 Arméniens) ont répondu grâce à une méthode procédant par sondage non aléatoire. Les buts principaux de cette recherche consistaient à vérifier à quels moyens avaient eu recours les groupes d'immigrants pour s'insérer dans la société tchèque et à déterminer dans quelle mesure ils s'estimaient satisfaits de leur nouvelle vie. Une attention particulière a été accordée à la recherche des facteurs importants ayant contribuéà fixer à la fois les caractéristiques communes et les particularités en matière de comportement. L'auteur s'est efforcé d'analy-ser la question à l'aide des statistiques quantitatives (test Chi carré, méthode AnswerTree). Le modèle des stratégies d'acculturation de Berry (1992) et le modèle d'assimilation segmentée de Portes et Zhou (par exemple 2000) servent de points de référence dans l'examen de questions conceptuelles. Les résultats montrent que l'incorporation des immigrants dans la société tchèque, a Prague, s'est traduite de différentes façons. Les Ukrainiens correspondent aux schémas spécifiques de transnationalisation qui leur sontpropres; les Vietnamiens constituent une communauté« prospère » mais se tenant à l'écart des autres; et les Arméniens pratiquent une stratégie évidente d'assimilation, tout en se rapprochant du courant central sur le plan du statut socio-économique. Sur la base de différentes indications, il semble que l'incorporation réussie dans la société tchèque soit liée au mode d'assimilation. Pour résumer, les immigrés les plus satisfaits de leur qualité de vie sont ceux pour qui il n'est pas important de vivre auprès de leurs compatriotes et ceux dont les connaissances de la langue tchèque parlée sont audessus de la moyenne. Le niveau de satisfaction le plus bas est celui des immigrés qui préfèrent rester en contact étroit avec leur compatriotes, ceux quijouissent d'une éducation de niveau universitaire et ceux dont le revenu se situe dans une tranche basse. Une bonne connaissance de la langue tchèque semble être la clé de la satisfaction des immigrés. Este artículo se basa en un estudio realizado por la Oficina de la Organización Internacional para las Migraciones (OIM) en Praga y la Facultad de Ciencias de la Universidad Charles de Praga, durante el último trimestre de 2003 y el primer trimestre de 2004. Recurriendo al cuestionario y al método de muestreo improbable se encuestó a 126 inmigrantes de primera generación en Praga (51 ucranios, 45 vietnamitas y 30 armenios). Los objetivos principales del estudio fueron determinar los modos de inserción de los grupos de inmigrantes en la sociedad checa y su nivel de satisfacción con relación a sus nuevas vidas. Se concedió particular atención a otros importantes factores subyacentes, a saber, las características comunes y los patrones particulares de comportamiento. En este artículo se analiza la cuestión mediante: estadísticas cuantitativas (la prueba de Chi-square, el método del Árbol de Respuestas); el modelo de estrategias de aculturación de Berry (1992); y el modelo de asimilación segmentada de Portes y Zhou (2000) que sirvieron de referencia a la hora de debatir cuestiones conceptuales. Los resultados apuntan a que la inserción de los inmigrantes en la sociedad checa, concretamente en Praga, se ha desarrollado según patrones específicos: los ucranios recurren a patrones típicos de transnacionalización, los vietnamitas son unacomunidad "acomodada" pero que se halla separaday segregada, mientras que los armenios utilizan un patrón claro de inserción, al tiempo que intentan incorporarse a la corriente principal en lo que atañe a su estatus socioeconómico. Sobre la base de diversas indicaciones, parece que una asimilación acertada en la sociedad checa depende del modo de inserción. En otras palabras, los inmigrantes más satisfechos con su calidad de vida son aquellos que no consideran importante vivir cerca de sus compatriotas y cuyos conocimientos del checo hablado superan la media. El índice más bajo de satisfacción se observa en los inmigrantes que prefieren vivir cerca de sus compatriotas, realizaron estudios universitarios y perciben bajos ingresos. Por lo visto, el buen conocimiento del idioma checo es la clave en la satisfacción de los inmigrantes. [source] Validation of crystallographic models containing TLS or other descriptions of anisotropyACTA CRYSTALLOGRAPHICA SECTION D, Issue 8 2010Frank Zucker The use of TLS (translation/libration/screw) models to describe anisotropic displacement of atoms within a protein crystal structure has become increasingly common. These models may be used purely as an improved methodology for crystallographic refinement or as the basis for analyzing inter-domain and other large-scale motions implied by the crystal structure. In either case it is desirable to validate that the crystallographic model, including the TLS description of anisotropy, conforms to our best understanding of protein structures and their modes of flexibility. A set of validation tests has been implemented that can be integrated into ongoing crystallographic refinement or run afterwards to evaluate a previously refined structure. In either case validation can serve to increase confidence that the model is correct, to highlight aspects of the model that may be improved or to strengthen the evidence supporting specific modes of flexibility inferred from the refined TLS model. Automated validation checks have been added to the PARVATI and TLSMD web servers and incorporated into the CCP4i user interface. [source] Redefining Affective Disorders: Relevance for Drug DevelopmentCNS: NEUROSCIENCE AND THERAPEUTICS, Issue 1 2008Steven D Targum The evaluation of new drug entities with specific modes of action may be hampered by rigid diagnostic classification systems and patient selection processes that do not focus on the anticipated symptomatic, behavioral, and functional outcomes to be achieved. Patients enrolled in central nervous system (CNS) clinical trials may present with a heterogeneous group of symptoms representing several syndromes or subtypes, subsumed under the same diagnosis in the DSM-IV classification system. As a result, enrolled patients may not have the valid illness characteristics of interest to the particular study. We propose that clinical drug development needs to focus on the primary nosological entity likely to be affected by a new drug entity's mode of action. Ideally, a valid patient will have the acute primary symptoms that the novel drug is supposed to influence. In this article, we propose operational criteria to delineate a more symptom-specific and ecologically valid approach to the identification of the valid patient for clinical trials. [source] | ||||||||||||||||