2,733 research outputs found

    On the pricing of the GLWB option in a Variable Annuity contract

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    Mariangela Scorrano, "On the pricing of the GLWB option in a Variable Annuity contract", DEAMS Research Paper Series 2015, N° 1, Trieste, EUT Edizioni Università di Trieste, 2015, pp.30This paper proposes a valuation model for the GLWB option using tractable financial and stochastic mortality processes in a continuous time framework. The policy has been analyzed assuming a static approach, in which policy holders withdraw each year just the guaranteed amount. Specifically we have considered as basic model the one proposed by Fungetal. (2014) and then we have generalized it introducing more realistic assumptions. In particular, we have taken into account a CIR stochastic process for the term structure of interest rates and a Heston model for the volatility of the underlying account, analyzing their effect on the fair price of the contract. We have addressed these two hypotheses separately at first, and jointly afterwards. As part of our analysis, we have implemented the theoretical model using a Monte Carlo approach. To this end, we have created ad hoc codes based on the programming language MATLAB, exploiting its fast matrix-computation facilities", DEAMS Research Paper Series 2014, N° 1, Trieste, EUT Edizioni Università di Trieste, 2015, pp.2

    Visions of a Colony: History on (dis)play at the Museum of Sydney

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    When it first opened in 1995, the Museum of Sydney (MoS) received praise from some quarters for its innovative representations of the city’s history, but it was increasingly criticised for its inaccessibility due to its postmodern approach. This highlights the tension between curatorial style and content that museums must negotiate in order to meet the needs of their audiences. Taking MoS as a case study, this article argues that public history museums are limited in their ability to break new ground when they must also remain accessible and relevant to the publics they serve

    Less than perfect divorces: dysregulated mitochondrial fission and neurodegeneration

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    Research efforts during the last decade have deciphered the basic molecular mechanisms governing mitochondrial fusion and fission. We now know that in mammalian cells mitochondrial fission is mediated by the large GTPase dynamin-related protein 1 (Drp1) acting in concert with outer mitochondrial membrane (OMM) proteins such as Fis1, Mff, and Mief1. It is also generally accepted that organelle fusion depends on the action of three large GTPases: mitofusins (Mfn1, Mfn2) mediating membrane fusion on the OMM level, and Opa1 which is essential for inner mitochondrial membrane fusion. Significantly, mutations in Drp1, Mfn2, and Opa1 have causally been linked to neurodegenerative conditions. Despite this knowledge, crucial questions such as to how fission of the inner and outer mitochondrial membranes are coordinated and how these processes are integrated into basic physiological processes such as apoptosis and autophagy remain to be answered in detail. In this review, we will focus on what is currently known about the mechanism of mitochondrial fission and explore the pathophysiological consequences of dysregulated organelle fission with a special focus on neurodegenerative conditions, including Alzheimer's, Huntington's and Parkinson's disease, as well as ischemic brain damag

    Parametric excitation of dc current in a single-dot shuttle system via spontaneous symmetry breaking

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    We investigate theoretically the dynamics of a spatially symmetric shuttle system subjected to an ac gate voltage. We demonstrate that in such a system parametric excitation gives rise to mechanical vibrations when the frequency of the ac signal is close to the eigenfrequency of the mechanical subsystem. These mechanical oscillations result in a dc shuttle current in a certain direction due to spontaneous symmetry breaking. The direction of the current is determined by the phase shift between the ac gate voltage and the parametrically excited mechanical oscillations. The dependence of the shuttle current on the dc gate voltage is also analyzed

    Single cell analysis reveals the involvement of the long non-coding RNA Pvt1 in the modulation of muscle atrophy and mitochondrial network

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    Long non-coding RNAs (lncRNAs) are emerging as important players in the regulation of several aspects of cellular biology. For a better comprehension of their function, it is fundamental to determine their tissue or cell specificity and to identify their subcellular localization. In fact, the activity of lncRNAs may vary according to cell and tissue specificity and subcellular compartmentalization. Myofibers are the smallest complete contractile system of skeletal muscle influencing its contraction velocity and metabolism. How lncRNAs are expressed in different myofibers, participate in metabolism regulation and muscle atrophy or how they are compartmentalized within a single myofiber is still unknown. We compiled a comprehensive catalog of lncRNAs expressed in skeletal muscle, associating the fiber-type specificity and subcellular location to each of them, and demonstrating that many lncRNAs can be involved in the biological processes de-regulated during muscle atrophy. We demonstrated that the lncRNA Pvt1, activated early during muscle atrophy, impacts mitochondrial respiration and morphology and affects mito/autophagy, apoptosis and myofiber size in vivo. This work corroborates the importance of lncRNAs in the regulation of metabolism and neuromuscular pathologies and offers a valuable resource to study the metabolism in single cells characterized by pronounced plasticity

    Current trends in Smart City initiatives: some stylised facts

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    The concept of Smart City (SC) as a means to enhance the life quality of citizen has been gaining increasing importance in the agendas of policy makers. However, a shared definition of SC is not available and it is hard to identify common global trends. This paper provides with a comprehensive understanding of the notion of SC through the elaboration of a taxonomy of pertinent application domains, namely: natural resources and energy, transport and mobility, buildings, living, government, and economy and people. It also explores the diffusion of smart initiatives via an empirical study aimed at investigating the ratio of domains covered by a city's best practices to the total of potential domains of smart initiatives and at understanding the role that various economic, urban, demographic, and geographical variables might have in influencing the planning approach to create a smarter city. Results reveal that the evolution patterns of a SC highly depend on its local context factors. In particular, economic development and structural urban variables are likely to influence a city's digital path, the geographical location to affect the SC strategy, and density of population, with its associated congestion problems, might an important component to determine the routes for the SC implementation. This work provides policy makers and city managers with useful guidelines to define and drive their SC strategy and planning actions towards the most appropriate domains of implementatio

    Coming together to define membrane contact sites.

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    Close proximities between organelles have been described for decades. However, only recently a specific field dealing with organelle communication at membrane contact sites has gained wide acceptance, attracting scientists from multiple areas of cell biology. The diversity of approaches warrants a unified vocabulary for the field. Such definitions would facilitate laying the foundations of this field, streamlining communication and resolving semantic controversies. This opinion, written by a panel of experts in the field, aims to provide this burgeoning area with guidelines for the experimental definition and analysis of contact sites. It also includes suggestions on how to operationally and tractably measure and analyze them with the hope of ultimately facilitating knowledge production and dissemination within and outside the field of contact-site research

    FSS-based approach for the power transmission enhancement through electrically small apertures

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    Cataloged from PDF version of article.In this paper, a novel approach, based on the employment of frequency selective surfaces, to enhance the power transmission through sub-wavelength apertures at the microwave frequencies is presented. A heuristic interpretation of the phenomenon is given, as well as an analytical model, based on the transmission line network representation. Finally, the performance of the proposed structure is validated through a set of full-wave numerical simulations. © 2011 Springer-Verlag
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