915 research outputs found
Assessment of average muscle fiber conduction velocity from surface EMG signals during fatiguing dynamic contractions
No full textTransport properties for liquid silicon-oxygen-iron mixtures at Earth's core conditions
No full textWe report on the thermal and electrical conductivities of two liquid silicon-oxygen-iron mixtures (Fe0.82Si0.10O0.08 and Fe0.79Si0.08O0.13), representative of the composition of the Earth's outer core at the relevant pressure-temperature conditions, obtained from density functional theory calculations with the Kubo-Greenwood formulation. We find thermal conductivities k=100(160) W m−1 K−1, and electrical conductivities σ=1.1(1.3)×106 Ω−1 m−1 at the top (bottom) of the outer core. These values are between two and three times higher than previous estimates, and have important implications for our understanding of the Earth's thermal history and the functioning of the Earth's magnetic field, including rapid cooling rate for the whole core or high level of radiogenic elements in the core. We also show results for a number of structural and dynamic properties of the mixtures, including the partial radial distribution functions, mean square displacements, viscosities, and speeds of sound
System, Subjekt, Topos: Für ein Lexikon des deutschen Idealismus
No full textDie Nomenklatur des von Hans-Jörg Sandkühler herausgegebenen Deutscher Idealismus-Handbuchs ist bündig. Sie ist dem Inhalt der neun Abschnitte zu gewinnen, die die folgenden Begriffe bzw. Begriffspaare umfassen: die Vernunft und das Absolute, System und Methode, die Erkenntnis und das Wissen, die Natur, Freiheit, Moral und Sittlichkeit, das Recht und der Staat, die Geschichte, die Religion und der Gottesbegriff, das Schöne und die Kunst. Dabei wäre auf die Verwendung des griechischen Artikels tò acht zu geben. Es gäben nämlich eine Vernunft, ein Absolutes, aber verschiedene Systeme, verschiedene Methoden usw. Damit liegt der Forschung einen schönen Anfang vor, wohl aber noch nicht die Vollendung einer Aufgabe, deren Grundlinien der vorliegende Beitrag umreißen möchte. Wolfgang Neuser hat mit Recht darauf hingewiesen, die Wurzeln mancher Aspekte der idealistischen Philosophie seien zunächst in der Renaissance wiederaufzufinden und von da noch weiter rückwärts bis in die Antike – man denke an das Thema des Anfangs. In diesem Beitrag geht es um die Wurzeln des idealistischen Denkens in der Renaissance. In darauffolgenden Forschungen werden die Texte für sich reden und zwar im Einklang mit der von Tullio Gregory initiierten und am Istituto per il Lessico Intellettuale Europeo e Storia delle Idee-CNR seit 1964 praktizierten lexikalischen Erfassung
How serious can the stealth bias be in gravitational wave parameter estimation?
No full textThe upcoming direct detection of gravitational waves will open a window to probing the strong-field regime of general relativity. As a consequence, waveforms that include the presence of deviations from general relativity have been developed (e.g., in the parametrized post-Einsteinian approach). TIGER, a data analysis pipeline which builds Bayesian evidence to support or question the validity of general relativity, has been written and tested. In particular, it was shown that the LIGO and Virgo detectors can probe deviations from general relativity in a regime than cannot be tested by Solar System tests or pulsar timing measurements. However, evidence from several detections is required before a deviation from general relativity can be confidently claimed. An interesting consequence is that, should general relativity not be the correct theory of gravity in its strong field regime, using standard general relativity templates for the matched filter analysis of interferometer data will introduce biases in the gravitational wave measured parameters with potentially serious consequences on the astrophysical inferences, such as the coalescence rate or the mass distribution. In this work we consider three heuristic possible deviations from general relativity and show that the biases introduced in the estimated parameters of gravitational waves emitted during the inspiral phase of spinless compact binary coalescence systems assuming the validity of general relativity manifest in various ways. The mass parameters are usually the most affected, with biases that can be as large as 30 standard deviations for the symmetric mass ratio, and nearly one percent for the chirp mass, which is usually estimated with subpercent accuracy. Other parameters do not show a significant bias. We conclude that statements about the nature of the observed sources, e.g., if both objects are neutron stars, depend critically on the explicit assumption that general relativity is the right theory of gravity in the strong field regime.National Science Foundation (U.S.)National Science Foundation (U.S.) (Laser Interferometer Gravitational Wave Observatory cooperative Agreement PHY-0757058)National Science Foundation (U.S.) (Grant PHY-0923409)National Science Foundation (U.S.) (Grant PHY-0600953
Determinants of length of stay after cesarean sections in the Friuli Venezia Giulia Region (North-Eastern Italy), 2005–2015
No full textSince Italy has the highest cesarean section (CS) rate (38.1%) among all European countries, the containment of health care costs associated with CS is needed, along with control of length of hospital stay (LOS) following CS. This population based cross-sectional study aims to investigate LoS post CS (overall CS, OCS; planned CS, PCS; urgent/emergency CS, UCS), in Friuli Venezia Giulia (a region of North-Eastern Italy) during 2005–2015, adjusting for a considerable number factors, including various obstetric conditions/complications. Maternal and newborn characteristics (health care setting and timeframe; maternal health factors; child’s size factors; child’s fragility factors; socio-demographic background; obstetric history; obstetric conditions) were used as independent variables. LoS (post OCS, PCS, UCS) was the outcome measure. The statistical analysis was conducted with multivariable linear (LoS expressed as adjusted mean, in days) as well as logistic (adjusted proportion of LoS > 4 days vs. LoS ≤ 4 days, using a 4 day cutoff for early discharge, ED) regression. An important decreasing trend over time in mean LoS and LoS > ED was observed for both PCS and UCS. LoS post CS was shorter with parity and history of CS, whereas it was longer among non-EU mothers. Several obstetric conditions/complications were associated with extended LoS. Whilst eclampsia/pre-eclampsia and preterm gestations (33–36 weeks) were predominantly associated with longer LoS post UCS, for PCS LoS was significantly longer with birthweight 2.0–2.5 kg, multiple birth and increasing maternal age. Strong significant inter-hospital variation remained after adjustment for the major clinical conditions. This study shows that routinely collected administrative data provide useful information for health planning and monitoring, identifying inter-hospital differences that could be targeted by policy interventions aimed at improving the efficiency of obstetric care. The important decreasing trend over time of LoS post CS, coupled with the impact of some socio-demographic and obstetric history factors on LoS, seemingly suggests a positive approach of health care providers of FVG in decision making on hospitalization length post CS. However, the significant role of several obstetric conditions did not influence hospital variation. Inter-hospital variations of LoS could depend on a number of factors, including the capacity to discharge patients into the surrounding non-acute facilities. Further studies are warranted to ascertain whether LoS can be attributed to hospital efficiency rather than the characteristics of the hospital catchment area
Constraints on the binary black hole nature of GW151226 and GW170608 from the measurement of spin-induced quadrupole moments
No full textAccording to the "no-hair" conjecture, a Kerr black hole (BH) is completely described by its mass and spin. In particular, the spin-induced quadrupole moment of a Kerr BH with mass and dimensionless spin can be written as , where . Thus by measuring the spin-induced quadrupole parameter , we can test the binary black hole nature of compact binaries and distinguish them from binaries comprised of other exotic compact objects, as proposed in [N. V. Krishnendu et al., PRL 119, 091101 (2017)]. Here, we present a Bayesian framework to carry out this test where we measure the symmetric combination of individual spin-induced quadrupole moment parameters fixing the anti-symmetric combination to be zero. The analysis is restricted to the inspiral part of the signal as the spin-induced deformations are not modeled in the post-inspiral regime. We perform detailed simulations to investigate the applicability of this method for compact binaries of different masses and spins and also explore various degeneracies in the parameter space which can affect this test. We then apply this method to the gravitational wave events, GW151226 and GW170608 detected during the first and second observing runs of Advanced LIGO and Advanced Virgo detectors. We find the two events to be consistent with binary black hole mergers in general relativity. By combining information from several more of such events in future, this method can be used to set constraints on the black hole nature of the population of compact binaries that are detected by the Advanced LIGO and Advanced Virgo detectors
Testing general relativity using Bayesian model selection: Applications to observations of gravitational waves from compact binary systems
No full textSecond-generation interferometric gravitational-wave detectors, such as Advanced LIGO and Advanced Virgo, are expected to begin operation by 2015. Such instruments plan to reach sensitivities that will offer the unique possibility to test general relativity in the dynamical, strong-field regime and investigate departures from its predictions, in particular, using the signal from coalescing binary systems. We introduce a statistical framework based on Bayesian model selection in which the Bayes factor between two competing hypotheses measures which theory is favored by the data. Probability density functions of the model parameters are then used to quantify the inference on individual parameters. We also develop a method to combine the information coming from multiple independent observations of gravitational waves, and show how much stronger inference could be. As an introduction and illustration of this framework-and a practical numerical implementation through the Monte Carlo integration technique of nested sampling-we apply it to gravitational waves from the inspiral phase of coalescing binary systems as predicted by general relativity and a very simple alternative theory in which the graviton has a nonzero mass. This method can (and should) be extended to more realistic and physically motivated theories. © 2011 American Physical Society
Kant’s Latin in Class
No full textThis chapter shall look into a number of issues, starting with some definitions pertaining to literary genres, passing through institutional requirements con- cerning scheduling and textbooks, and ending with Kant’s use of Latin in class, documented by the substantial number of Latin lines written by Kant in his inter- leaved copy of Georg Friedrich Meier’s Auszug aus der Vernunftlehre, which goes back to Kant’s practice of dictating in Latin during his repetitoria. What were the reasons for Kant’s keeping to Latin? The last issue is about Kant’s Critique of Pure Reason as having been originally conceived as a textbook for lectures on aes- thetics, logic, and metaphysics. This chapter is also about showing the influence on intellectual production of literary genres and especially of those related to academic teaching. Philolo- gists point to the need to keep apart the different roles played, e. g., in ancient philosophy by literary genres such as pragmateía, dialogos, lógos protreptikós, lógos sumpotikós, eisagogé, próblema, diatribé, chreía, aphorismós, apophthegma, gnóme, as well as by Latin genres such as epistulae, consolationes, and memora- bilia (Untersteiner 1980: 51–101). During the last fifty years, not many historians of philosophy have considered it worthy of their efforts to consider the manifold relations between philosophical innovation and literary genres. The information provided by Giorgio Tonelli, who proposed an assessment of Kant’s oeuvre based on titles and formats, stands out (Tonelli 1955: 55). Today, studies like those of Tonelli have been taken as models by researchers who are about to close the gap between “philosophical history of philosophy” and “historical history of philoso- phy,” while elaborating on the interdisciplinary approach of what used to be the “history of ideas” and is now “intellectual history” (Gregory 2006; Hotson 2007; Sgarbi 2010)
A Systematic Evaluation of Hospital Performance of Childbirth Delivery Modes and Associated Factors in the Friuli Venezia Giulia Region (North-Eastern Italy), 2005–2015
No full textCesarean sections (CS) have become increasingly common in both developed and developing countries, raising legitimate concerns regarding their appropriateness. Since improvement of obstetric care at the hospital level needs quantitative evidence, using routinely collected health data we contrasted the performance of the 11 maternity centres (coded with an alphabetic letter A to L) of an Italian region, Friuli Venezia Giulia (FVG), during 2005–15, after removing the effect of several factors associated with different delivery modes (DM): spontaneous vaginal delivery (SVD), instrumental vaginal delivery (IVD), overall CS (OCS) and urgent/emergency CS (UCS). A multivariable logistic regression model was fitted for each individual DM, using a dichotomous outcome (1 = each DM; 0 = rest of hospital births) and comparing the stratum specific estimates of every term with their respective reference categories. Results were expressed as odds ratios (OR) with 95% confidence intervals (95%CI). The Benjamini-Hochberg (BH) false discovery rates (FDR) approach was applied to control alpha error due to the large number of statistical tests performed. In the entire FVG region during 2005–2015, SVD were 75,497 (69.1% out of all births), IVD were 7,281 (6.7%), OCS were 26,467 (24.2%) and UCS were 14,106 (12.9% of all births and 53.3% out of all CS). SVD were more likely (in descending order of statistical significance) with: higher number of previous livebirths; clerk/employed occupational status of the mother; gestational age 40 weeks. The principal factors associated with OCS were (in descending order of statistical significance): CS history, breech presentation, non-reassuring fetal status, obstructed labour, multiple birth, placental weight ≥ 600 g, eclampsia/pre-eclampsia, maternal age ≥ 35 and oligohydramnios. The most important risk factors for UCS were (in descending order of statistical significance): placenta previa/abruptio placenta/ antepartum hemorrage; non-reassuring fetal status, obstructed labour; breech presentation; PROM, eclampsia/pre-eclampsia; gestation 33–36 weeks; gestation 41+ weeks; oligohydramnios; birthweight <2,500 g, maternal age ≥ 35 and cord prolapse. After removing the effects of all other factors, we found great variability of DM rates across hospitals. Adjusting for all risk factors, all hospitals had a OCS risk higher than the referent (hospital G). Out of these 10 hospitals with increased adjusted risk of OCS, 9 (A, B, C, D, E, F, I, J, K) performed less SVD and 5 (A, C, D, I, J) less IVD. In the above 5 centres CS was therefore probably overused. The present study shows that routinely collected administrative data provide useful information for health planning and monitoring. Although the overall CS rate in FVG during 2005–15 was 24.2%, well below the corresponding average Italian national figure (38.1%), the variability of DM rates across FVG maternity centres could be targeted by policy interventions aimed at reducing the recourse to unnecessary CS. In some clinical conditions such as obstructed labor, non-reassuring fetal status, breech presentation, history of CS, higher maternal age and multiple birth, consideration may be given to more conservative DM. The overuse of CS in nulliparas and repeat CS (RCS) should be carefully monitored and subject to audit
Method, model, and memory: Perspectiva Pictorum et Architectorum, by Andrea Pozzo
No full textA la fin du XVIIe siècle, le jésuite Andrea Pozzo (1642 - 1709) publie, à Rome, le traité Perspectiva Pictorum et Architectorum (1693 et 1700). Cet ouvrage visait à présenter aux peintres et architectes un moyen pratique et rapide de réaliser la perspective. En raison de ce caractère, l\u27œuvre a connu une diffusion rapide, étant rééditée, imprimée et traduite en plusieurs langues. Dans cet article, les questions liées au traité sont abordées, de trois manières : en tant que méthode didactique de réalisation de dessins en perspective, basée sur l\u27expérience de l\u27auteur ; comme modèle d\u27architecture, basé sur la représentation de formes et d\u27inventions classiques et de nouvelles solutions ; et, enfin, comme souvenir des actes de l\u27auteur et de la Compagnie de Jésus, dont il faisait partie.No final do século XVII o jesuíta Andrea Pozzo (1642 - 1709) publicou, em Roma, o tratado Perspectiva Pictorum et Architectorum (1693 e 1700). Essa obra objetivava apresentar a pintores e arquitetos um modo prático e rápido de se realizar a perspectiva. Por esse caráter, a obra conheceu rápida difusão, sendo reeditada, impressa e traduzida em diversas línguas. Neste artigo discutem-se questões relativas ao tratado, em três vias: como um método didático de se realizar desenhos em perspectiva, baseado na experiência do autor; como modelo para a arquitetura, em função da representação de formas clássicas e de invenções e novas soluções; e, por fim, como memória dos feitos do autor e da Companhia de Jesus, da qual fazia parte.A finales del siglo XVII, el jesuita Andrea Pozzo (1642 - 1709) publicó en Roma el tratado Perspectiva Pictorum et Architectorum (1693 y 1700). Este trabajo tuvo como objetivo presentar a pintores y arquitectos una forma práctica y rápida de realizar la perspectiva. Debido a esto, el tratado se difundió rápidamente, siendo reimpreso y traducido a varios idiomas. Este artículo discute temas relacionados con el tratado, de tres formas: como método didáctico para hacer dibujos en perspectiva, basado en la experiencia del autor; como modelo para la arquitectura, debido a la representación de formas clásicas, invenciones y nuevas soluciones; y, finalmente, como memoria de las obras del autor y de la Compañía de Jesús, de la que formó parte.At the end of the XVIIth century, the Jesuit Andrea Pozzo (1642 - 1709) published in Rome the treatise Perspectiva Pictorum et Architectorum (1693 e 1700). This work aimed to present to painters and architects an easy and quick method to make perspectives. The treatise was largely known and was re-edited, reprinted, and translated in several languages. In this paper we discuss questions about the treatise in three ways: as a didactical method to make perspective designs, based on the author’s experience; as an architectural model with its representations of classical forms, inventions, and new solutions; and, at last, as a memory of the author and of the Society of Jesus, which he has been part of
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