451 research outputs found

    Il Carcer nella produzione di Cardano

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    Alongside a larger analysis of Cardano's moral philosophy since the De consolatione (1542), the essay focuses on the dialogue Carcer, and suggests a relationship between the difficulties encountered by the author in the Duchy of Milan in 1560-61, and the trial of 1570 in Bologna. Special attention is devoted to the philosophical reasons that support in the Carcer the Plutarchean sera numinis vindicta, one of Cardano's favorites topics

    Comparing three possible hypoelliptic Laplacians on the 5-dimensional Cartan group via div-curl type estimates

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    On general Carnot groups, the definition of a possible hypoelliptic Hodge-Laplacian on forms using the Rumin complex has been considered in (M. Rumin, “Differential geometry on C-C spaces and application to the Novikov-Shubin numbers of nilpotent Lie groups,” C. R. Acad. Sci., Paris Sér. I Math., vol. 329, no. 11, pp. 985–990, 1999, M. Rumin, “Sub-Riemannian limit of the differential form spectrum of contactmanifolds,” Geom. Funct. Anal., vol. 10, no. 2, pp. 407–452, 2000), where the author introduced a 0-order pseudodifferential operator on forms. However, for questions regarding regularity for example, where one needs sharp estimates, this 0-order operator is not suitable. Up to now, there have only been very few attempts to define hypoelliptic Hodge- Laplacians on forms that would allow for such sharp estimates. Indeed, this question is rather difficult to address in full generality, the main issue being that the Rumin exterior differential dc is not homogeneous on arbitrary Carnot groups. In this note, we consider the specific example of the free Carnot group of step 3 with 2 generators, and we introduce three possible definitions of hypoelliptic Hodge-Laplacians.We compare how these three possible Laplacians can be used to obtain sharp div-curl type inequalities akin to those considered by Bourgain & Brezis and Lanzani & Stein for the de Rham complex, or their subelliptic counterparts obtained by Baldi, Franchi & Pansu for the Rumin complex on Heisenberg groups

    Possession

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    This chapter of the Historical Latin Syntax traces the evolution and use of predicative possessive constructions from Archaic to Late Latin. We demonstrate that, far from being merely a so-called “be-language”, Latin is a language where the major possessive type is based on a transitive verb (habeo) since the archaic stage. A textual, contrastive analysis of the habeo x and mihi est x types proves that between these two constructions there is a functional differentiation (i.e. syntactic and pragmatic, while the semantic level is relevant only to a minor extent). This, thus, explains: their different occurrence in the Latin corpus; their division-of-labour and, therefore, their coexistence through the history of Latin; and, finally, the diahronic evolution towards the transitive type. A comparison between the mihi est x and the genitive predicative type, which are fully differentiated on a functional plane, completes the picture of the whole architecture of predicative possession in Latin. Consequences can be drawn on the general plane, as “mixted” types (i.e. languages that are both have- and be-), such as Latin, must be taken into consideration when we approach the typology of predicative possession. An analysis of attributive constructions is then offered, at the light of parameters such as: the order of the elements in the sequence, the definite status of the possessor/possessum constituents of the phrase, the semantic profile of the relation expressed, and the different morphological markers, etc.. Conclusions partly confirm previous hypotheses about the relation between the Latin stage and the Indoeuropean stage, while several generalizations from the typological point of view have to be adjusted (e.g. external possessor constructions). The part on predicative possession is mainly due to Andrea Nuti; the part on attributive possession mainly to Philip Baldi. However, as the whole chapter is the result of a deep, mutual work carried on in full cooperation, the authors have agreed not to state explicitly and neatly an author-to-pages correspondence

    Adaptive synchronization in networks with heterogeneous uncertain Kuramoto-like units

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    We analyze adaptive synchronization capabilities in networks with Kuramoto-like units whose dynamical features are unknown and thus synchronization protocols must exhibit co-evolution capabilities. In the presence of heterogeneous and uncertain units, synchronization should be enabled by appropriate adaptive protocols that counteract the effect of heterogeneity. An interaction protocol is presented that is used by the units to communicate with each other: the protocol is based on a distributed disagreement measure. The aim of the protocol is to adapt feedback and coupling gains, so as to guarantee the emergence of a synchronous solution. The adaptive strategy is distributed, i.e. each unit self-determines the strength of its gains by using only neighboring measurements. Convergence of the synchronization error to zero is shown via Lyapunov analysis, and numerical examples demonstrate the effectiveness of the proposed protocol.Accepted Author ManuscriptTeam Bart De Schutte

    Valuing a Leveraged Buyout: Expansion of the Adjusted Present Value by means of Real Options Analysis

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    A major flaw in using the adjusted present value (APV) method to value the target firm of a leveraged buyout is that it results in systematic undervaluation of the firm in question. The author proposes to remedy the problem by employing real options analysis to expand the target firm's APV on its equity side. Two real options may be identified as being inherent in the leveraged buyout structuring process: a financial default call option and an operating default call option, both of American type. The resulting expanded equity value allows for the flexible management of firm value uncertainty while continuing to incorporate the extra value creation deriving from the exploitation of the tax shield

    A distributed disagreement-based protocol for synchronization of uncertain heterogeneous agents

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    In networks with heterogeneous and uncertain agents, fixed-gain control can lead to synchronization only if the uncertainties are relatively small. If the uncertainties are larger, we need to develop adaptive-gain approaches to achieve synchronization. In this work we propose an adaptive synchronization protocol, in case of full-state measurement, for uncertain heterogeneous agents based on a distributed disagreement reasoning. Specifically, we first define unknown gains (feedback and coupling gains) that could lead all agents to a homogeneous behavior and thus synchronization: however, since these gains are unknown in view of the unknown dynamics, we design adaptive laws for these gains that lead the agents toward synchronization. The adaptive laws are driven by a disagreement error which is calculated among neighbors: a Lyapunov analysis is presented for showing convergence of the synchronization error to zero.Accepted Author ManuscriptTeam Bart De Schutte

    The XMM-Newton long look of NGC 1365: uncovering of the obscured X-ray source

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    We present an analysis of the extreme obscuration variability observed during an XMM–Newton 5-d continuous monitoring of the active galactic nuclei (AGN) in NGC 1365. The source was in a reflection-dominated state in the first ∼1.5 d, then a strong increase in the 7–10 keV emission was observed in ∼10 h, followed by a symmetric decrease. The spectral analysis of the different states clearly shows that this variation is due to an uncovering of the X-ray source. From this observation, we estimate a size of the X-ray source DS < 1013 cm, a distance of the obscuring clouds R∼ 1016 cm and a density n∼ 1011 cm−3. These values suggest that the X-ray absorption/reflection originates from the broad-line region clouds. This is also supported by the resolved width of the iron narrow Kα emission line, consistent with the width of the broad Hβ line

    Adaptive leader-follower synchronization over heterogeneous and uncertain networks of linear systems without distributed observer

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    A challenging task in network synchronization is steering the network toward a coherent solution, when the dynamics of the constituent systems are heterogeneous and uncertain. In this situation, synchronization can be achieved via adaptive protocols (with adaptive feedback gains or adaptive coupling gains, or both). However, as state-of-the-art synchronization methods adopt a distributed observer architecture, they require to communicate extra observer variables among neighbors, in addition to the neighbors' states (or outputs). The distinguishing feature of this article is to show that for heterogeneous and uncertain networks of some classes of linear systems, synchronization is possible without the need for any distributed observer. Such classes are in line with those in model reference adaptive control literature. Lyapunov analysis is used to derive a new adaptive synchronization protocol with the simplest communication architecture, in which both feedback and coupling gains are adapted without any extra communication other than neighbors' states (in the full-state information case) or neighbors' outputs (in the partial-state information case). Accepted Author ManuscriptTeam Bart De Schutte

    A New Minimally Invasive Mesotherapy Technique for Facial Rejuvenation

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    Introduction: This study describes a pivotal clinical trial of a new minimally invasive mesotherapy technique for facial rejuvenation. Methods: The authors utilized two formulations: formulation A with hyaluronic acid, vitamins, amino acids, minerals, coenzymes, and antioxidant substances; formulation B with hyaluronic acid and idebenone. Fifty participants were enrolled in the study and divided in two groups. Group 1 (50-65 years) treated with formulation A. Group 2 (35-50 years) treated with formulation B. The groups underwent four sessions of mesotherapy involving multiple injections. Treatment was conducted at 15 day intervals. All participants had pre- and posttreatment photographs. Punch biopsies were taken from randomly selected participants, baseline and after 6 weeks, and stained for interleukin (IL)-6, IL- 1b, matrix metalloproteinase (MMP)-1, and collagen 1. Clinical evaluation was based on the Global Aesthetic Scale (GAIS) and on the Wrinkle Severity Rating Scale (WSRS). Results: The results produced were statistically analyzed and resulted in a significant and long-lasting effect on facial rejuvenation. Evaluation of photographs at 0, 1, and 2 months revealed significant clinical improvement: brightness, texture, and firmness of the skin. The analysis of the GAIS and WSRS scores in the two groups demonstrated statistically significant results after 2 months. The biopsies taken from randomly selected participants at baseline and after 3 months showed a decrease in IL- 1b, IL-6, and MMP1, and an increase in collagen 1. Conclusion: The new minimally invasive mesotherapy technique described can improve the clinical appearance of the skin in different age groups. © The Author(s) 2013
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