Der Wert der Wissenschaft

Der Verfasser stellte das Buch aus Einzelartikeln zusammen. Es umfasst die Kapitel: 1. Anschauung und Logik in der Mathematik (vgl. auch http://www.ub.uni-heidelberg.de/archiv/13357), 2. Das Maß der Zeit, 3. Der Begriff des Raumes, 4. Der Raum und seine drei Dimensionen, 5. Die Analysis und die Physik, 6. Die Astronomie, 7. Geschichte der mathematischen Physik, 8. Die gegenwärtige Krise der mathematischen Physik, 9. Die Zukunft der mathematischen Physik, 10. Ist die Wissenschaft künstlich?, 11. Die Wissenschaft und die Wirklichkeit. Die 1904 verfassten Aufsätze zur mathematischen Physik beschreiben den Umbruch zu Beginn des 20. Jahrhunderts und sind somit selbst wieder ein Stück Wissenschaftsgeschichte

Anschauung und Logik in der Mathematik : mit Anmerkungen von Heinrich Weber. Du rôle de l'intuition et de la logique en mathématiques / digitale Ausgabe erstellt von Gabriele Dörflinger

Henri Poincaré hielt den Schlussvortrag des 2. Internationalen Mathematikerkongresses am 11. August 1900 in Paris. Darin gibt er der Überzeugung Ausdruck, dass sowohl die für jede Weiterentwicklung nötige Intuition als auch die Sicherheit verschaffende Logik unverzichtbar für die Mathematik sind. Diesen Vortrag nahm er in leicht modifizierter Form 1905 in sein Buch ,,La valeur de la science'' auf. Emilie Weber, die bereits 1911 verstorbene Tochter des Mathematikers Heinrich Weber, übersetzte 1906 die Aufsatzsammlung ins Deutsche. Heinrich Weber ergänzte die Übersetzung mit Anmerkungen und Zusätzen

Structures de quelques poèmes d’Agrippa d’Aubigné

Le concept même de baroque appliqué à la poésie ou au théâtre a d’abord été lié à certaines notions de structures, mais ces structures étaient empruntées aux arts plastiques. M. Marcel Raymond a ouvert un champ fécond aux recherches, en tentant de transposer dans le domaine littéraire les catégories définies par Wölfflin pour l’architecture. Il nous semble qu’aujourd’hui le développement du structuralisme en linguistique, ses premiers tâtonnements dans le domaine de l’analyse littéraire perme..

Correlates of Product Quality of Soumbala, a West African Non-timber Forest Product

Knowledge of the correlates of product quality is a prerequisite for further commercialisation of soumbala, a food product extracted from the leguminous tree Parkia biglobosa. In this study qualitative and quantitative data derived from interviews of producers and expert users are used to estimate the influence of Parkia biglobosa management practises, soumbala product processing practises, and nutritional composition of soumbala on perceived soumbala quality. Several variables on management practises correlated with high quality soumbala as revealed by binary logistic regression, with quality as the dependent variable and six management related variables as independent variables. Variables relating to product processing were examined using qualitative data from group sessions, gathering all the producers in a given village. Finally the relationship between nutritional compositions and soumbala quality was determined. The results show that local knowledge, management practises, and product processing practises are correlated with soumbala quality, whilst nutritional composition is a poor predictor of soumbala quality

Direct vascular contact is a hallmark of cerebral astrocytes

Astrocytes establish extensive networks via gap junctions that allow each astrocyte to connect indirectly to the vasculature. However, the proportion of astrocytes directly associated with blood vessels is unknown. Here, we quantify structural contacts of cortical astrocytes with the vasculature in vivo. We show that all cortical astrocytes are connected to at least one blood vessel. Moreover, astrocytes contact more vessels in deeper cortical layers where vessel density is known to be higher. Further examination of different brain regions reveals that only the hippocampus, which has the lowest vessel density of all investigated brain regions, harbors single astrocytes with no apparent vascular connection. In summary, we show that almost all gray matter astrocytes have direct contact to the vasculature. In addition to the glial network, a direct vascular access may represent a complementary pathway for metabolite uptake and distribution

Data series subtraction with unknown and unmodeled background noise

LISA Pathfinder (LPF), ESA's precursor mission to a gravitational wave observatory, will measure the degree to which two test-masses can be put into free-fall, aiming to demonstrate a residual relative acceleration with a power spectral density (PSD) below 30 fm/s$^2$/Hz$^{1/2}$ around 1 mHz. In LPF data analysis, the measured relative acceleration data series must be fit to other various measured time series data. This fitting is required in different experiments, from system identification of the test mass and satellite dynamics to the subtraction of noise contributions from measured known disturbances. In all cases, the background noise, described by the PSD of the fit residuals, is expected to be coloured, requiring that we perform such fits in the frequency domain. This PSD is unknown {\it a priori}, and a high accuracy estimate of this residual acceleration noise is an essential output of our analysis. In this paper we present a fitting method based on Bayesian parameter estimation with an unknown frequency-dependent background noise. The method uses noise marginalisation in connection with averaged Welch's periodograms to achieve unbiased parameter estimation, together with a consistent, non-parametric estimate of the residual PSD. Additionally, we find that the method is equivalent to some implementations of iteratively re-weighted least-squares fitting. We have tested the method both on simulated data of known PSD, and to analyze differential acceleration from several experiments with the LISA Pathfinder end-to-end mission simulator.Comment: To appear Phys. Rev. D90 August 201

S

We study the rheological behavior of concentrated granular suspensions of simple spherical particles. Under controlled stress, the system exhibits an S-shaped flow curve (stress vs. shear rate) with a negative slope in between the low-viscosity Newtonian regime and the shear thickened regime. Under controlled shear rate, a discontinuous transition between the two states is observed. Stress visualization experiments with a novel fluorescent probe suggest that friction is at the origin of shear thickening. Stress visualization shows that the stress in the system remains homogeneous (no shear banding) if a stress is imposed that is intermediate between the high and low-stress branches. The S-shaped shear thickening is then due to the discontinuous formation of a frictional force network between particles upon increasing the stress.Comment: 5 pages + 6 figure

230: Heightened risk of coronary atheroma conferred by a decrease in the plasma concentrations of lithocholic acid

ContextThe bile acids receptors Farsenoid X and TGR5 protect against the formation of atheroma in mice, though no evidence have linked coronary atheroma and bile acid in human. Bile acids links these receptors with more or less efficient activation, depending on the species.ObjectiveTo test the hypothesis that changes in concentrations of circulating bile acid species influence the risk of developing coronary atheromas in humans.MethodsPilot, prospective, observational study conducted between June and September 2010. The serum concentrations of cholic, chenodeoxycholic, deoxycholic, and lithocholic acids were measured in a fasting blood sample. Consecutive hospitalized or ambulatory patients undergoing emergency or elective coronary angiograms were eligible for inclusion. Post-cardiac arrest and non-fasting states, hepatic disease, and treatment with antimicrobials, corticosteroids, statins or fibrates were exclusion criteria. Of 393 screened patients, 44 met the study entry criteria, and were divided between 27 patients with (Group A) and 17 without (Group B) angiographically visible coronary atheromas. The pool of circulating bile acids was analyzed to measure the plasmatic concentrations of 28 different bile acid species. The variables associated with the presence of angiographically visible coronary atheromas were examined by single and multiple variable logistic regression analysis.ResultsThe serum lithocholic acid concentration was significantly lower in group A than in group B. By multiple variable analysis, lithocholic acid was the only predictor of coronary atheroma independently of patient gender (odds ratio 2.41 per 0.05 decrease; 95% confidence interval 1.11 to 5.25, P=0.027ConclusionA low serum concentration of lithocholic acid was an independent predictor of coronary atheroma in human