Value-at-Risk time scaling for long-term risk estimation

In this paper we discuss a general methodology to compute the market risk measure over long time horizons and at extreme percentiles, which are the typical conditions needed for estimating Economic Capital. The proposed approach extends the usual market-risk measure, ie, Value-at-Risk (VaR) at a short-term horizon and 99% confidence level, by properly applying a scaling on the short-term Profit-and-Loss (P&L) distribution. Besides the standard square-root-of-time scaling, based on normality assumptions, we consider two leptokurtic probability density function classes for fitting empirical P&L datasets and derive accurately their scaling behaviour in light of the Central Limit Theorem, interpreting time scaling as a convolution problem. Our analyses result in a range of possible VaR-scaling approaches depending on the distribution providing the best fit to empirical data, the desired percentile level and the time horizon of the Economic Capital calculation. After assessing the different approaches on a test equity trading portfolio, it emerges that the choice of the VaR-scaling approach can affect substantially the Economic Capital calculation. In particular, the use of a convolution-based approach could lead to significantly larger risk measures (by up to a factor of four) than those calculated using Normal assumptions on the P&L distribution.Comment: Pre-Print version, submitted to The Journal of Risk. 18 pages, 17 figure

The Reverse Transcriptase Encoded by LINE-1 Retrotransposons in the Genesis, Progression, and Therapy of Cancer

In higher eukaryotic genomes, Long Interspersed Nuclear Element 1 (LINE-1) retrotransposons represent a large family of repeated genomic elements. They transpose using a reverse transcriptase (RT), which they encode as part of the ORF2p product. RT inhibition in cancer cells, either via RNA interference-dependent silencing of active LINE-1 elements, or using RT inhibitory drugs, reduces cancer cell proliferation, promotes their differentiation and antagonizes tumor progression in animal models. Indeed, the nonnucleoside RT inhibitor efavirenz has recently been tested in a phase II clinical trial with metastatic prostate cancer patients. An in-depth analysis of ORF2p in a mouse model of breast cancer showed ORF2p to be precociously expressed in precancerous lesions and highly abundant in advanced cancer stages, while being barely detectable in normal breast tissue, providing a rationale for the finding that RT-expressing tumours are therapeutically sensitive to RT inhibitors. We summarise mechanistic and gene profiling studies indicating that highly abundant LINE-1-derived RT can sequester RNA substrates for reverse transcription in tumor cells, entailing the formation of RNA:DNA hybrid molecules and impairing the overall production of regulatory miRNAs, with a global impact on the cell transcriptome. Based on these data, LINE-1-ORF2 encoded RT has a tumor-promoting potential that is exerted at an epigenetic level. We propose a model whereby LINE1-RT drives a previously unrecognized global regulatory process, the deregulation of which drives cell transformation and tumorigenesis and possibly implicated in cancer cell heterogeneity

Monitoring of Urban Growth and its Related Environmental Impacts: Niamey Case Study (Niger)

AbstractThe present contribution is about a preliminary study of the evolution of Niamey city (Niger) during last decades.Recent advances in remote sensing, both in satellite hardware technology and image availability development, provide opportunities image collection and multitemporal analysis on urban form and size that can be useful for policy and planning. Some opportunities for, and limitations on, monitoring urban growth using remote sensing data are shown in the present contribution; moreover examples of environmental impacts of urban growth, as monitored with remote sensing, are provided in order to define future development of dumps and quarries and its environmental impacts on Niamey city

Georesources and Environmental Problems in Niamey City (Niger): A Preliminary Sketch

AbstractThe present paper is about a preliminary study of the georesources of Niamey (Niger). The main goals are the qualitative and quantitative characterization of surface water, groundwater, and aggregates. There was a census of the wells and quarries, an in situ characterization and a consequent sampling survey. Laboratory analyses were performed to evaluate chemical and physical features of water and aggregates. Thanks to a dedicated Geodatabase, schematic forms reporting the available data of wells and quarries were produced. The study evidenced the actual condition of surface water, groundwater and active and closed quarries, also highlighting local phenomena of pollution

Rocket science: a review of phytochemical & health-related research in Eruca & Diplotaxis species

Rocket species (Eruca spp. and Diplotaxis spp.) are becoming increasingly important leafy salad crops across the world. Numerous scientific research papers have been published in recent years surrounding the potential health benefits associated with phytochemicals contained in leaves, such as flavonoids and isothiocyanates. Other research of note has also been conducted into the unique taste and flavour properties of leaves, which can be hot, peppery, bitter, and sweet depending upon the genotype and phytochemical composition. While research into these aspects is increasing, some studies lack cohesion and in-depth knowledge of commercial breeding and cultivation practices that makes interpretation and application of results difficult. This review draws together all significant research findings in these crops over the last five years, and highlights areas that require further exploration and/or resolution. We also advise on experimental considerations for these species to allow for more meaningful utilisation of findings in the commercial sector

Patients' preferences for subcutaneous trastuzumab versus conventional intravenous infusion for the adjuvant treatment of HER2-positive early breast cancer: final analysis of 488 patients in the international, randomized, two-cohort PrefHer study

PrefHer revealed compelling and consistent patient preference for subcutaneous (s.c.) trastuzumab, regardless of delivery by single-use injection device or hand-held syringe. s.c. trastuzumab was well-tolerated and safety data, including immunogenicity, were consistent with previous reports. No new safety signals were identified compared with the known intravenous trastuzumab profile in early breast cance

Multiculturalità ed integrazione dei bambini stranieri nella scuola dell'infanzia

Dottorato di ricerca in Modelli di formazione, analisi teorica e comparazione, XXII ciclo, A.a. 2008-2009Università della calabria, Dipartimento di scienze dell'educazion