4,427 research outputs found
The 2D/3D dynamics of wall-bounded low-Rm magnetohydrodynamic (MHD) turbulence
No full textWith this experimental study, we give evidence that the dynamics of low-Rm MHD turbulence depends on the diffusion length l_z, which corresponds to the distance over which the Lorentz force is able to diffuse momentum before it is balanced by inertia
Nationale Sicherheitshinweise zur Verbesserung der Patientensicherheit in Spitälern nutzen: die Perspektive von Qualitäts- und Risk-Managern
No full textBACKGROUND
National safety alert systems publish relevant information to improve patient safety in hospitals. However, the information has to be transformed into local action to have an effect on patient safety. We studied three research questions: How do Swiss healthcare quality and risk managers (qm/rm(1)) see their own role in learning from safety alerts issued by the Swiss national voluntary reporting and analysis system? What are their attitudes towards and evaluations of the alerts, and which types of improvement actions were fostered by the safety alerts?
METHODS
A survey was developed and applied to Swiss healthcare risk and quality managers, with a response rate of 39 % (n=116). Descriptive statistics are presented.
RESULTS
The qm/rm disseminate and communicate with a broad variety of professional groups about the alerts. While most respondents felt that they should know the alerts and their contents, only a part of them felt responsible for driving organizational change based on the recommendations. However, most respondents used safety alerts to back up their own patient safety goals. The alerts were evaluated positively on various dimensions such as usefulness and were considered as standards of good practice by the majority of the respondents. A range of organizational responses was applied, with disseminating information being the most common. An active role is related to using safety alerts for backing up own patient safety goals.
CONCLUSIONS
To support an active role of qm/rm in their hospital's learning from safety alerts, appropriate organizational structures should be developed. Furthermore, they could be given special information or training to act as an information hub on the issues discussed in the alerts.Zusammenfassung
Hintergrund
Nationale Fehlermeldesysteme veröffentlichen relevante Information für die Verbesserung der Patientensicherheit in Spitälern. Damit die Warnhinweise einen Effekt auf die Patientensicherheit haben können, muss die enthaltene Information zu lokalen Maßnahmen führen. Wir untersuchten drei Fragestellungen: Wie die Qualitäts- und Risk-Manager (qm/rm2) Schweizer Spitäler ihre eigene Rolle beim Lernen aus Warnhinweisen („Quick-Alerts“), die vom freiwilligen Schweizer Berichts- und Analysesystem herausgegeben werden, einschätzen; welche Einstellungen und Bewertungen der Warnhinweise vorherrschen und welche Art von Verbesserungsmassnahmen durch die Warnhinweise entstanden sind.
Methoden
Ein Fragebogen wurde entwickelt und Schweizer Qualitäts- und Riskmanagern vorgelegt, mit einer Rücklaufquote von 39% (n = 116). Deskriptive Analysen werden berichtet.
Resultate
Die qm/rm verteilen die Warnhinweise und sprechen mit vielen unterschiedlichen Berufsgruppen über sie. Während die meisten Befragten angaben, dass sie die Warnhinweise kennen sollten, fühlte sich nur ein Teil von ihnen verantwortlich dafür, die darin empfohlenen Veränderungen vorzunehmen. Dennoch nutzten die meisten Befragten die Warnhinweise, um ihre eigenen Ziele bezüglich Patientensicherheit zu untermauern. Die Hinweise wurden auf verschiedenen Dimensionen positiv bewertet, beispielweise ihre Nützlichkeit, und sie wurden vom Großteil der Befragten als Standards für „good practice“ angesehen. Eine Reihe unterschiedlicher Maßnahmen wird genutzt, um die Hinweise zu bearbeiten, die häufigste unter ihnen war die Weiterverbreitung von Informationen.
Eine aktive Rolle bei der Bearbeitung der Warnhinweise wird vermehrt von jenen Befragten eingenommen, die die Warnhinweise auch nutzen, um ihre eigenen Patientensicherheitsziele zu untermauern.
Schlussfolgerungen
Um eine aktive Rolle der qm/rm beim Lernen aus Warnhinweisen im Spital zu unterstützen, sollten entsprechende organisationale Strukturen entwickelt werden. Des Weiteren könnten die qm/rm spezifische Hintergrundinformationen oder ein spezifisches Training erhalten, um für die Themen, die in den Warnhinweisen besprochen werden, als eine Art Informationsplattform zu fungieren
Triangular Constellations in Flows
No full textParticles advected on the surface of a fluid can exhibit fractal clustering. The local structure of a fractal set is described by its dimension , which is the exponent of a power-law relating the mass in a ball to its radius : . It is desirable to characterise the {\em shapes} of constellations of points sampling a fractal measure, as well as their masses. The simplest example is the distribution of shapes of triangles formed by triplets of points, which we investigate for fractals generated by chaotic dynamical systems. The most significant parameter describing the triangle shape is the ratio of its area to the radius of gyration squared. We show that the probability density of has a phase transition: is independent of and approximately uniform below a critical flow compressibility , which we estimate. For the distribution appears to be described by two power laws: when , and when
Exact two-dimensionalization of low-magnetic-Reynolds-number flows subject to a strong magnetic field
No full textWe investigate the behavior of flows, including turbulent flows, driven by a horizontal body-force and subject to a vertical magnetic field, with the following question in mind: for very strong applied magnetic field, is the flow mostly two-dimensional, with remaining weak three-dimensional fluctuations, or does it become exactly 2D, with no dependence along the vertical? We restrict attention to low-magnetic-Reynolds number (Rm) flow. Because liquid metals have low magnetic Prandtl number, such low- flows can have a kinetic Reynolds number as large as one million and therefore be strongly turbulent. We first focus on the quasi-static approximation, i.e. the asymptotic limit of vanishing magnetic Reynolds number Rm << 1: we prove that the flow becomes exactly 2D asymptotically in time, regardless of the initial condition and provided the interaction parameter N is larger than a threshold value. We call this property absolute two-dimensionalization: the attractor of the system is necessarily a (possibly turbulent) 2D flow. We then consider the full-magnetohydrodynamic equations and we prove that, for low enough Rm and large enough N, the flow becomes exactly two-dimensional in the long-time limit provided the initial vertically-dependent perturbations are infinitesimal. We call this phenomenon linear two-dimensionalization: the (possibly turbulent) 2D flow is an attractor of the dynamics, but it is not necessarily the only attractor of the system. Some 3D attractors may also exist and be attained for strong enough initial 3D perturbations. These results shed some light on the existence of a dissipative anomaly for magnetohydrodynamic flows subject to a strong external magnetic field
The Decay of Wall Bounded MHD Turbulence at Low RM
No full textWe have developed a new spectral method to simulate flows with very fine boundary layers present. We apply it to calculate the evolution of freely decaying MHD turbulence between isolating walls. By comparison them with results obtained in fully periodic domain we quantify the influence of the channel walls on the character of freely decaying MHD turbulence
A basis of a certain module for the hyperalgebra and some applications
No full textIn the hyperalgebra of the -th Frobenius kernel of the algebraic group , we construct a basis of the
-module generated by a certain element which was given by the
author before. As its applications, we also prove some results on the
-modules and the algebra .Comment: 30 page
Borromini tuscolano
No full textLa pubblicazione propone, in versione ampliata e aggiornata, la chiave di lettura già avanzata dall’autore alcuni anni or sono in relazione all’intervento seicentesco voluto dalla famiglia Falconieri sulla più antica delle Ville Tuscolane, la Rufina, ritenendone valida la consolidata attribuzione al Borromini.
Nel volume viene data un’ampia dimostrazione dell’efficacia dell’interazione “documenti storici-rilievo architettonico”, nella ricostruzione delle fasi evolutive di una fabbrica e di come questo momento d’analisi, ove insufficientemente approfondito, possa indurre a considerazioni erronee.
Infatti, l’ipotesi diffusa in vari contributi sull’argomento riguardo alla forma dell’originario Casino della Rufina – e in particolare alla posizione della loggia verso Roma – è suffragata soltanto da incisioni d’epoca e non è mai stata scientificamente comprovata dal riscontro di un rilievo, né dal confronto attento con la pianta del nucleo originario della fabbrica conservata nelle Carte Strozzi presso l’Archivio di Stato di Firenze, ignorata o considerata – con una certa superficialità – come inattendibile.
L’ipotesi qui sostenuta valuta la “logica” dell’addizione alla Villa Rufina basandosi su considerazioni relative sia ai vari documenti iconografici sia all’attendibilità di ciascuno; il tutto è inoltre riferito al completo rilevamento dell’opera nel suo stato attuale.
Discutendo ipotesi diverse (anche attributive) emerse nel frattempo e sviluppando le considerazioni precedentemente avanzate grazie anche a un nuovo apparato iconografico che vede sfruttate le potenzialità della modellazione 3D applicate ai criteri del rilievo filologico, il lavoro tende a ribadire l’efficacia di tale metodo d’indagine, basato sul rilievo delle attuali condizioni dell’opera in associazione all’imprescindibile analisi storico-documentale.
Attraverso il medesimo impianto scientifico procedurale è inoltre sviluppata la ricostruzione filologica del fronte settentrionale, basata anche su documentazione fotografica d’epoca parzialmente inedita. Si intende così offrire un iniziale – seppur parziale – contributo alla rilettura dell’ultima fase (quella novecentesca) che ha contrassegnato la fabbrica, vedendola già alterata ai primi del XX secolo, quindi compromessa dagli eventi bellici e infine trasformata dalle operazioni di restauro/ripristino del complesso, che hanno riproposto solo parzialmente e in modo generico la precedente morfologia del manufatto.This publication proposes, in an expanded and updated version, the key that the Author had already advanced in an earlier essay which was published ten years ago, concerning the 17th century intervention on the Villa Rufina: the first one of the Ville Tuscolane (summer residences for the papal circle that rose, in the late Renaissance, on the hills at the south of Rome). The Authors assumes also to be valid the well-established attribution of this work to Francesco Borromini.
In this volume a wide demonstration is offered of the efficacy, for the aim of a reliable reconstruction of the evolutionary phases of a certain building, of the interaction between the historical documents and the architectural survey, showing also how this time of analysis can lead to incorrect or misleading considerations, when it is not carried out enough deeply.
In the second phase (the expansion of the 17th century) which characterized all the Ville Tuscolane, the Rufina, at the time owned by the Falconieri (family), was the subject of an extensive renewal. With this intervention the first bulding that had initiated the “modern rediscovery” of building activity in these places (being, in fact, the originator of the Complex) was considerably transformed with regard to its material structure, appearance and relationship with the environment. For the devising of the general plan, it is commonly ascribed to Francesco Borromini, on the basis more of archive documents than of its style.
If the decoration of the Villa has been extensively and reliably studied, the same cannot be said about the transformations that the old building underwent, especially with regard to the lost loggia towards Rome. The hypothesis that has gradually taken root, about the location of this lodge, in the various papers published on the subject, is in fact supported only by some engravings of the time (in which the Villa is depicted in a pseudo-perspectival view and only as an element amongst the many others of the Complex). It has never been scientifically proved by the check of a survey, or by a careful comparison with the plan of the original nucleus of the original factory map stored in the “Carte Strozzi” at the State Archives of Florence, that has been ignored or considered – with some superficiality – as unreliable.
The hypothesis the Author suggested since the previous essay, evaluates the “logic” of the addition Borromini made to the Villa Rufina detaching itself from these assumptions and basing itself on some specific considerations concerning the iconographic documents that have been published over the years in various contributions, evaluating the reliability of each of them. These considerations were also related to a comprehensive survey of the work in its current state, as the so far published surveys are partial or were carried out on the structure as extensively damaged by the war.
In the volume are also discussed several different hypotheses that emerged in the meantime, also on the allocation of the project, as the attribution to Borromini – which in the past had seen ups and downs, from the header of the engraving by Alessandro Specchi to the evidences provided by Paolo Portoghesi and by Angela Negro, taken from the Falconieri-Carpegna archive – has recently been the subject of a new attempt of denial.
Developing the considerations already advanced before, and using a new display of subsidiary iconography that sees the exploitation of the potential of 3d modeling when applied to the criteria of the philological surveying, this study aims at a confirmation of the effectiveness of this method of investigation, which is based on a survey of the work in its positive state in conjunction with an unavoidable historical-documentary analysis.
On the basis of this same scientific procedural system, taking as well in account many historical photographic documents, so far unpublished, is also developed a philological reconstruction of the northern front, that is proposed in the last chapter. The aim is to provide a first – although partial – contribution to the re-reading of the last phase (the 20th century), which marked the building, that had already been altered in the early years of the 20th century, then compromised by the war and finally transformed by the restoration and rehabilitation of the complex, which reconstructed the pre-existing morphology only in a partial and general way
Changes in dominant groups of the gut microbiota do not explain cereal-fiber induced improvement of whole-body insulin sensitivity
No full textBackground
Diets high in cereal-fiber (HCF) have been shown to improve whole-body insulin sensitivity. In search for potential mechanisms we hypothesized that a supplemented HCF-diet influences the composition of the human gut microbiota and/or biomarkers of colonic carbohydrate fermentation.
Methods
We performed a randomized controlled 18-week intervention in group-matched overweight participants. Fecal samples of 69 participants receiving isoenergetic HCF (cereal-fiber 43 g/day), or control (cereal-fiber 14 g/day), or high-protein (HP, 28% of energy-intake, cereal-fiber 14 g/day), or moderately high cereal fiber/protein diets (MIX; protein 23% of energy-intake, cereal-fiber 26 g/day) with comparable fat contents were investigated for diet-induced changes of dominant groups of the gut microbiota, and of fecal short-chain fatty-acids (SCFA) including several of their proposed targets, after 0, 6, and 18-weeks of dietary intervention. In vitro fermentation of the cereal fiber extracts as used in the HCF and MIX diets was analyzed using gas chromatography. Diet-induced effects on whole-body insulin-sensitivity were measured using euglycaemic-hyperinsulinemic clamps and re-calculated in the here investigated subset of n = 69 participants that provided sufficient fecal samples on all study days.
Results
Gut microbiota groups and biomarkers of colonic fermentation were comparable between groups at baseline (week 0). No diet-induced differences were detected between groups during this isoenergetic intervention, neither in the full model nor in uncorrected subgroup-analyses. The cereal-fiber extract as used for preparation of the supplements in the HCF and MIX groups did not support in vitro fermentation. Fecal acetate, propionate, and butyrate concentrations remained unchanged, as well as potential targets of increased SCFA, whereas valerate increased after 6-weeks in the HP-group only (p = 0.037). Insulin-sensitivity significantly increased in the HCF-group from week-6 (baseline M-value 3.8 ± 0.4 vs 4.3 ± 0.4 mg·kg-1·min-1, p = 0.015; full model 0-18-weeks, treatment-x-time interaction, p = 0.046).
Conclusions
Changes in the composition of the gut microbiota and/or markers of colonic carbohydrate fermentation did not contribute explaining the observed early onset and significant improvement of whole-body insulin sensitivity with the here investigated HCF-diet
Convective Ripening and Rainfall
No full textThis paper discusses the evolution of the droplet size distribution for a liquid-in-gas aerosol contained in a Rayleigh-B\'enard cell. It introduces a non-collisional model for broadening the droplet size distribution, termed \lq convective ripening'. The paper also considers the initiation of rainfall from ice-free cumulus clouds. It is argued that while collisional mechanisms cannot explain the production of rain from clouds with water droplet diameters of , the non-collisional convective ripening mechanism gives a much faster route to increasing the size of the small fraction of droplets that grow into raindrops
The Singer or the Song? Developments in Performers' Rights from the Perspective of a Cultural Economist
No full textOver the last century, performers gradually acquired statutory protection of their economic and moral
rights. These rights are not copyright in the legal sense but neighboring rights and until recently, they
were mainly remuneration rights that are collectively administered. With the WPPT (WIPO
Performers and Phonograms Treaty), performers now have individual exclusive rights for digital
performances; this leads to the question: what has motivated this change – is it a change in the
perception of the value of performer or a change brought about by the changing technology of copying or,
indeed, a change that reflects different economic costs and benefits? The paper discusses the role of
copyright law as an incentive to performers and asks if the economic role of the performer is so different
from that of the author. The conclusion is that a complex interaction of the legal regulations, economic
conditions and institutional arrangements for administering these new rights will determine the outcome
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