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Selected AbstractsEthnic origin and increased risk for schizophrenia in immigrants to countries of recent and longstanding immigrationACTA PSYCHIATRICA SCANDINAVICA, Issue 5 2010M.-J. Dealberto Dealberto M-J. Ethnic origin and increased risk for schizophrenia in immigrants to countries of recent and longstanding immigration. Objectives:, Compare the risk for schizophrenia in immigrants to countries of recent and longstanding immigration. Compare prevalence and incidence rates in black subjects under different conditions. Method:, An electronic literature search was complemented by review articles and cross-references. Studies reporting standard diagnosis and incidence or prevalence rates were included. Results:, Immigrants had an increased risk for schizophrenia in countries of longstanding immigration, but with lower risk ratios than in those of recent immigration. The risk was higher in black immigrants and the black population living in the United States. But incidence and prevalence rates in Africa and the Caribbean were similar to those of international studies. Conclusion:, Comparing the most recent generation of immigrants with descendants of previous ones may account for the lower risk ratios observed in countries of longstanding vs. recent immigration. Two neurobiological hypotheses are proposed to explain the epidemiological findings in black populations and in immigrants. [source] Complete reconstruction of the retinal laminar structure from a cultured retinal pigment epithelium is triggered by altered tissue interaction and promoted by overlaid extracellular matricesDEVELOPMENTAL NEUROBIOLOGY, Issue 14 2009Fusako Kuriyama Abstract The retina regenerates from retinal pigment epithelial (RPE) cells by transdifferentiation in the adult newt and Xenopus laevis when it is surgically removed. This was studied under a novel culture condition, and we succeeded, for the first time, in developing a complete retinal laminar structure from a single epithelial sheet of RPE. We cultured a Xenopus RPE monolayer sheet isolated from the choroid on a filter cup with gels overlaid and found that the retinal tissue structure differentiated with all retinal layers present. In the culture, RPE cells isolated themselves from the culture substratum (filter membrane), migrated, and reattached to the overlaid gel, on which they initiated transdifferentiation. This was exactly the same as observed during in vivo retina regeneration of X. laevis. In contrast, when RPE monolayers were cultured similarly without isolation from the choroid, RPE cells proliferated, but remained pigmented instead of transdifferentiating, indicating that alteration in tissue interaction triggers transdifferentiation. We then examined under the conventional tissue culture condition whether altered RPE-choroid interaction induces Pax6 expression. Pax6 was upregulated in RPE cells soon after they were removed from the choroid, and this expression was not dependent of FGF2. FGF2 administration was needed for RPE cells to maintain Pax6 expression. From the present results, in addition to our previous ones, we propose a two-step mechanism of transdifferentiation: the first step is a reversible process and is initiated by the alteration of the cell-extracellular matrix and/or cell,cell interaction followed by Pax6 upregulation. FGF2 plays a key role in driving RPE cells into the second step, during which they differentiate into retinal stem cells. © 2009 Wiley Periodicals, Inc. Develop Neurobiol, 2009 [source] Neurogenesis may relate to some but not all types of hippocampal-dependent learningHIPPOCAMPUS, Issue 5 2002Tracey J. Shors Abstract The hippocampal formation generates new neurons throughout adulthood. Recent studies indicate that these cells possess the morphology and physiological properties of more established neurons. However, the function of adult generated neurons is still a matter of debate. We previously demonstrated that certain forms of associative learning can enhance the survival of new neurons and a reduction in neurogenesis coincides with impaired learning of the hippocampal-dependent task of trace eyeblink conditioning. Using the toxin methylazoxymethanol acetate (MAM) for proliferating cells, we tested whether reduction of neurogenesis affected learning and performance associated with different hippocampal dependent tasks: spatial navigation learning in a Morris water maze, fear responses to context and an explicit cue after training with a trace fear paradigm. We also examined exploratory behavior in an elevated plus maze. Rats were injected with MAM (7 mg/kg) or saline for 14 days, concurrent with BrdU, to label new neurons on days 10, 12, and 14. After treatment, groups of rats were tested in the various tasks. A significant reduction in new neurons in the adult hippocampus was associated with impaired performance in some tasks, but not with others. Specifically, treatment with the antimitotic agent reduced the amount of fear acquired after exposure to a trace fear conditioning paradigm but did not affect contextual fear conditioning or spatial navigation learning in the Morris water maze. Nor did MAM treatment affect exploration in the elevated plus maze. These results combined with previous ones suggest that neurogenesis may be associated with the formation of some but not all types of hippocampal-dependent memories. Hippocampus 2002;12:578,584. © 2002 Wiley-Liss, Inc. [source] A study on the lumped preconditioner and memory requirements of FETI and related primal domain decomposition methodsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 13 2008Yannis Fragakis Abstract In recent years, domain decomposition methods (DDMs) have emerged as advanced solvers in several areas of computational mechanics. In particular, during the last decade, in the area of solid and structural mechanics, they reached a considerable level of advancement and were shown to be more efficient than popular solvers, like advanced sparse direct solvers. The present contribution follows the lines of a series of recent publications on the relationship between primal and dual formulations of DDMs. In some of these papers, the effort to unify primal and dual methods led to a family of DDMs that was shown to be more efficient than the previous methods. The present paper extends this work, presenting a new family of related DDMs, thus enriching the theory of the relations between primal and dual methods, with the primal methods, which correspond to the dual DDM that uses the lumped preconditioner. The paper also compares the numerical performance of the new methods with that of the previous ones and focuses particularly on memory requirement issues related to the use of the lumped preconditioner, suggesting a particularly memory-efficient formulation. Copyright © 2007 John Wiley & Sons, Ltd. [source] Non-invasive ventilation in do-not-intubate patients: five-year follow-up on a two-year prospective, consecutive cohort studyACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 9 2009H.-H. BÜLOW Background: End-of-life decisions are common in intensive care units (ICUs), and increasingly, non-invasive ventilation (NIV) is used as a ceiling of ventilatory care. However, little is known about the outcome following that decision. Methods: An observational, single-center, retrospective, follow-up study with no interventions, on ICU patients treated with NIV and a do-not-intubate (DNI) order. The patients were followed until a 5-year survival rate could be calculated. Results: One hundred and fifty-seven patients were treated with NIV during 2002 and 2003, and among 38 a DNI order was in effect. Of the 38 DNI patients, 11 died in the ICU, 16 died on the ward and 11 survived the hospital stay. Five of these 11 survivors died within 6 months, two died after 2.7 and 3.3 years, respectively, but four were still alive after 5 years. The long-term (>6 months) survivors have, surprisingly only been admitted to the hospital 0,2 times a year , and seldom with the need for ICU treatment. Conclusions: According to this study, and previous ones, it seems worthwhile treating DNI patients with NIV. Twenty-five to 35% leave the hospital alive, every 6th patient lives for at least 1 year, and this paper shows that 10% may survive for 5 years or more. However, only chronic obstructive pulmonary disease and chronic heart failure patients (both with a concomitant low APACHE score) seem to have a reasonable outcome, and patients should be informed about this. So far, no study has investigated the quality of life of these survivors. [source] Newly developed basis sets for density functional calculationsJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 2 2005S. Chiodo Abstract Optimized contracted Gaussian basis sets of double-zeta valence polarized (DZVP) quality for first-row transition metals are presented. The DZVP functions were optimized using the PWP86 generalized gradient approximation (GGA) functional and the B3LYP hybrid functional. For a careful analysis of the basis sets performance the transition metal atoms and cations excitation energies were calculated and compared with the experimental ones. The calculated values were also compared with those obtained using the previously available DZVP basis sets developed at the local-density functional level. Because the new basis sets work better than the previous ones, possible reasons of this behavior are analyzed. The newly developed basis sets also provide a good estimation of other atomic properties such as ionization energies. © 2004 Wiley Periodicals, Inc. J Comput Chem 26: 175,183, 2005 [source] Fountain flow revisited: The effect of various fluid mechanics parametersAICHE JOURNAL, Issue 5 2010Evan Mitsoulis Abstract Numerical simulations have been undertaken for the benchmark problem of fountain flow present in injection-mold filling. The finite element method (FEM) is used to provide numerical results for both cases of planar and axisymmetric domains under laminar, isothermal, steady-state conditions for Newtonian fluids. The effects of inertia, gravity, surface tension, compressibility, slip at the wall, and pressure dependence of the viscosity are all considered individually in parametric studies covering a wide range of the relevant parameters. These results extend previous ones regarding the shape of the front, and in particular the centerline front position, as a function of the dimensionless parameters. The pressures from the simulations have been used to compute the excess pressure losses in the system (front pressure correction or exit correction). Inertia leads to highly extended front positions relative to the inertialess Newtonian values, which are 0.895 for the planar case and 0.835 for the axisymmetric one. Gravity acting in the direction of flow shows the same effect, while gravity opposing the flow gives a reduced bulge of the fountain. Surface tension, slip at the wall, and compressibility, all decrease the shape of the front. Pressure-dependence of the viscosity leads to increased front position as a corresponding dimensionless parameter goes from zero (no effect) to higher values of the pressure-shift factor. The exit correction increases monotonically with inertia, compressibility, and gravity, while it decreases monotonically with slip and pressure-dependence of the viscosity. Contour plots of the primary variables (velocity-pressure) show interesting trends compared with the base case (zero values of the dimensionless parameters and of surface tension). © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] A simple HPLC-MS method for the quantitative determination of the composition of bacterial medium chain-length polyhydroxyalkanoatesJOURNAL OF SEPARATION SCIENCE, JSS, Issue 10 2008Andreas Grubelnik Abstract Bacterial poly(hydroxyalkanoates) (PHAs) vary in the composition of their monomeric units. Besides saturated side-chains, unsaturated ones can also be found. The latter leads to unwanted by-products (THF ester, secondary alcohols) during acidic cleavage of the polymer backbone in the conventional analytical assays. To prevent these problems, we developed a new method for the reductive depolymerization of medium chain-length PHAs, leading to monomeric diols that can be separated and quantified by HPLC/MS. Reduction is performed at room temperature with lithium aluminum hydride within 5,15 min. The new method is faster and simpler than the previous ones and is quantitative. The results are consistent with the ones obtained by quantitative 1H NMR. [source] Archival note: An inquiry into the relationshp between Alfred Binet and Cyril BurtJOURNAL OF THE HISTORY OF THE BEHAVIORAL SCIENCES, Issue 3 2003Diana Faber Ph.D. honorary research fellowship Two recent archival items offer material for analysis of Alfred Binet's (1857,1911) and Cyril Burt's (1883,1971) relationship in the early twentieth century. Burt's letter to Binet's biographer Theta Wolf was an answer to her request for information about his contact with Binet. An analysis of Burt's account prompts more questions than it answers. His statements in the letter are compared with previous ones and are put into the context of the activities of the two men, but these do not enlighten us about his actual relations with Binet. The problem arises because of Burt's desciptive vagueness and lack of supporting evidence. Despite attacks against Burt's integrity made from 1976 onward, we found no conclusive evidence of false claims. The negative outcome of this analysis probably results from Burt's faulty memory, and herein lies the caveat that personal memories make unreliable material for historical accounts. © 2003 Wiley Periodicals, Inc. [source] Immigrants' Relative Earnings in Sweden , A Cohort AnalysisLABOUR, Issue 2 2006Mats Hammarstedt Immigrants from Nordic and Western European countries have a smaller entry earnings disadvantage and slower rate of assimilation than other groups of immigrants. For some cohorts of immigrants from European countries the initial earnings disadvantage disappears after 15,20 years in Sweden, but as non-European immigrants suffered from very large entry earnings disadvantages, their earnings will not catch up with the earnings of natives during their first 20 years in Sweden. More recent non-European immigrant cohorts had a larger entry earnings disadvantage than previous ones. The immigration policy, discrimination, and the economic conditions may have contributed to the decline in the earnings assimilation of non-European immigrants. [source] Amplitude,shape approximation as an extension of separation of variablesMATHEMATICAL METHODS IN THE APPLIED SCIENCES, Issue 3 2008N. Parumasur Abstract Separation of variables is a well-known technique for solving differential equations. However, it is seldom used in practical applications since it is impossible to carry out a separation of variables in most cases. In this paper, we propose the amplitude,shape approximation (ASA) which may be considered as an extension of the separation of variables method for ordinary differential equations. The main idea of the ASA is to write the solution as a product of an amplitude function and a shape function, both depending on time, and may be viewed as an incomplete separation of variables. In fact, it will be seen that such a separation exists naturally when the method of lines is used to solve certain classes of coupled partial differential equations. We derive new conditions which may be used to solve the shape equations directly and present a numerical algorithm for solving the resulting system of ordinary differential equations for the amplitude functions. Alternatively, we propose a numerical method, similar to the well-established exponential time differencing method, for solving the shape equations. We consider stability conditions for the specific case corresponding to the explicit Euler method. We also consider a generalization of the method for solving systems of coupled partial differential equations. Finally, we consider the simple reaction diffusion equation and a numerical example from chemical kinetics to demonstrate the effectiveness of the method. The ASA results in far superior numerical results when the relative errors are compared to the separation of variables method. Furthermore, the method leads to a reduction in CPU time as compared to using the Rosenbrock semi-implicit method for solving a stiff system of ordinary differential equations resulting from a method of lines solution of a coupled pair of partial differential equations. The present amplitude,shape method is a simplified version of previous ones due to the use of a linear approximation to the time dependence of the shape function. Copyright © 2007 John Wiley & Sons, Ltd. [source] A note on spectrum distribution of constraint preconditioned generalized saddle point matricesNUMERICAL LINEAR ALGEBRA WITH APPLICATIONS, Issue 6 2009Zhi-Hao Cao Abstract In this note, results concerning the eigenvalue distribution and form of the eigenvectors of the constraint preconditioned generalized saddle point matrix and its minimal polynomial are given. These results extend previous ones that appeared in the literature. Copyright © 2009 John Wiley & Sons, Ltd. [source] Theory of laser cooling of semiconductor quantum wellsPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 6 2008G. Rupper Abstract We present a microscopic many-body theory of laser cooling of semiconductor quantum wells. The cooling mechanism is the upconversion of pump photons through absorption and subsequent luminescence by an electron,hole,exciton mixture maintained at steady state in the quantum well. Assuming this Coulomb plasma to be in quasi-thermal equilibrium, our theory calculates its absorption/luminescence spectra within a diagrammatic (real-time) Green's function approach at the self-consistent T-matrix level. These spectra are used in a cooling threshold analysis for GaAs quantum wells that also takes into account other losses into heat. We compare the present results with previous ones obtained for bulk GaAs. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Synthesis of well-defined chain-end-functionalized polystyrenes with four, eight, and sixteen perfluorooctyl groups and their surface characterizationPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 1-2 2004Akira Hirao Abstract We have successfully synthesized a series of novel well-defined chain-end-functionalized polystyrenes with a definite number of four, eight, and sixteen perfluorooctyl (C8F17) groups, via living anionic polymerization, by the coupling reaction of chain-end-functionalized polystyrenes with dendritic benzyl bromide moieties with the functionalized 1,1-diphenylalkylanion prepared from sec -BuLi and 1,1-bis(4- tert -butyldimethylsilyloxyphenyl)ethylene, deprotection, and a Williamson reaction with C8F17(CH2)3Br. The resulting polymers were precisely controlled in molecular weight and molecular weight distribution as well as well-defined in chain-end-functionality. Surface structures of the annealed films cast from such chain-end-functionalized polystyrenes with C8F17 groups have been characterized by contact angle and angle-dependent X-ray photoelectron spectroscopy (XPS) measurements. It has been clearly observed by both measurements that the C8F17 groups are preferentially segregated from their polystyrene main chains and significantly enriched at the surfaces. However, the degree of enrichment of C8F17 group increased only to a small extent by increasing the C8F17 group from four, eight, and even sixteen in number. We have compared the present results with the previous ones obtained by using chain-end-functionalized polystyrenes with one, two, three, and four C8F17 groups and the structurally analogous block copolymers and discussed in more detail in terms of the dependence of enrichment degree on number of C8F17 group. Copyright © 2004 John Wiley & Sons, Ltd. [source] Ageing in granular aluminium insulating thin filmsANNALEN DER PHYSIK, Issue 12 2009J. Delahaye Abstract We present a new set of electrical field effect measurements on granular aluminium insulating thin films. We have explored how the conductance relaxations induced by gate voltage changes depend on the age of the system, namely the time elapsed since its quench at low temperature. A clear age dependence of the relaxations is seen, qualitatively similar to ageing effects seen in other well studied glassy systems such as spin glasses or polymers. We explain how our results differ from the previous ones obtained with different protocols in indium oxide and granular aluminium thin films. Our experimental findings bring new information on the dynamics of the system and put new constraints on the theoretical models that may explain slow conductance relaxations in disordered insulators. [source] Determination of physical behaviour of feed pellets in Mediterranean waterAQUACULTURE RESEARCH, Issue 2 2006Paolo Vassallo Abstract Settled uneaten feed causes the most intense impact under sea cages, and settling velocity of the feed pellets represents a key parameter for waste dispersion models. Even if some data about physical properties of feed pellets have been published in the framework of salmonid rearing, there is a complete lack of information related to the Mediterranean Sea, as regards typical values of temperature, salinity and feed composition for Gilthead Sea Bream (Sparus aurata L.) and Sea Bass (Dicentrarchus labrax L.). In this study we try to fill this lack, determining dimensions, water adsorption properties, floating times and settling velocities of a typical growing sequence of pellets for the species mentioned above, under defined laboratory conditions reproducing Mediterranean Sea water. The settling velocity increases with pellet size from 0.087, for the smallest pellet (3 mm), to 0.144 m s,1, for the 5 mm pellet. The biggest extruded pellet (6 mm) falls slower (0.088 m s,1). The floating time before pellet's fall is found to be a critical parameter in determining settling velocity. The latter depends on pellet's size, water temperature and salinity. The examined pellets reach a 42% of weight increase after 10 min of immersion, while no appreciable dimension change is observed. Our results are in part different from previous ones and could play a role in evaluating and modelling Mediterranean aquaculture environmental impact. [source] Longitudinal study of veterinary students and veterinarians: effects of growing up on a farm with animalsAUSTRALIAN VETERINARY JOURNAL, Issue 7 2007TJ Heath Objective To compare the career paths of veterinarians who had grown up on farms with animals with those of veterinarians from other backgrounds, during the first 15 years after they graduated. Procedure Questionnaires were completed by veterinary students in their first and fifth year, and after 1, 5, 10 and 15 years after they graduated. The most recent questionnaires were returned by 134 of 137 graduates, 20% of whom had grown up, or lived for at least two years, on farms where animals were a primary source of income. This paper includes findings from that questionnaire but also contains comparisons with previous ones. Results Fifteen years after they graduated, veterinarians who had grown up on farms with animals were more likely than those of other backgrounds to be living in centres with < 10,000 people (58% farm, 20% other), irrespective of the type of work they were doing. Although they were more likely to be doing no veterinary work (42% farm, 21% other), they were also more likely to be working in mixed practice (15% farm, 9% other) and with cattle and sheep generally (11% full time equivalent farm, 5% full time equivalent other). However, > 80% of those who had started their careers in mixed practice were no longer in mixed practice after 15 years. Veterinarians of farm origin who were in private practice were more likely to be sole or part owners (93% farm, 46% other) and less likely to be employees (7% farm, 54% other). Conclusions In this study, veterinarians who had grown up on farms with animals seemed slightly more likely than those from other backgrounds to continue working in mixed practice and to work with cattle or sheep, although the numbers were small and the differences not significant. Whatever their background, the majority who started their careers in mixed practice left over the next few years, and by 15 years only 15% remained. [source] Naturwissenschafts-, Technik- und Medizingeschichte in Deutschland, 1997,2004.BERICHTE ZUR WISSENSCHAFTSGESCHICHTE, Issue 1 2005Literaturbericht über die Forschung an den Institutionen. Diese Bibliographie der naturwissenschafts-, technik- und medizingeschichtlichen Forschungsliteratur für die Erscheinungsjahre 1997 bis 2004 setzt die vorangegangenen Übersichten fort. Sie beinhaltet die seit 1997 erschienene Literatur und beruht wiederum auf der Nennung durch die Institutionen selbst, allerdings auf Wunsch des Deutschen Nationalkomitees der IUHPS/DHS beschränkt auf zehn Angaben pro Wissenschaftler(in). Einige Einrichtungen haben zudem auf ihre jeweilige Homepage verwiesen. Auch die persönlichen Homepages der einzelnen Forscher(innen) sind für weitere Literatur-Angaben heranzuziehen. Die Reihenfolge der Autor(inn)en ist am Alphabet der Namen orientiert und nicht mehr an dem der Institutionen. Die Kodierung hinter dem Namen ordnet die Institution zu. Ein systematischer Überblick findet sich im Anschluß an diesen Hinweis. Länger als vorgesehen dauert der Aufbau einer elektronischen Datenbank für die hier angesprochenen Wissenschaftsfelder. Hierin liegt auch der Grund für die rückwärtige Aufnahme bis zum Jahr 1997, da es zu dem bis dahin vorgesehenen Start der Datenbank schon nicht gekommen war. Die zukünftigen Datenbanken sollen in Dresden (für die Technikgeschichte), in München (für die Naturwissenschaftsgeschichte) und in Leipzig (für die Medizingeschichte) entstehen, doch haben sich trotz der abermals dankbar entgegengenommenen Hilfe der Deutschen Forschungsgemeinschaft (DFG) für diesen hier vorgestellten Überblick die sich für zuständig haltenden Bundesländer bislang ihren Verpflichtungen zu einem solchen Basisprojekt der Literaturrecherche weitgehend entzogen. Die , in mehrfacher Hinsicht betroffenen , Wissenschaftler(innen) hoffen auf größere Einsicht. Diese Übersicht wäre ohne den unermüdlichen Einsatz von Frau Verena Witte M. A., Bochum, nicht möglich gewesen. Daher gilt ihr unser besonderer Dank. This compilation of German research in history of science, technology, and medicine for the years 1997 to 2004 will continue the previous ones. Researchers of the institutions have given us these information, however, only up to ten indications were requested by the national committee of the IUHPS/DHS. More research results may be found on the homepages of the larger institutes and of most of the individual researchers. The list adheres to the alphabet of the authors names, no longer to that of the institutions. After this note you will find the survey of them. A new national data base is proceeding very slowly and completion might still last some time in a country where this kind of research is considered to be of regional importance only ,! This compilation was again supported by the national German science foundation (DFG), which we appreciated very much. The compilation work was mainly done thanks to the efforts of Verena Witte MA, Bochum. [source] | |||||||||||||||||||||||||