140,067 research outputs found
A Risk Management Approach for Portfolio Insurance Strategies
No full textControlling and managing potential losses is one of the main objectives of the Risk Management. Following Ben Ameur and Prigent (2007) and Chen et al. (2008), and extending the first results by Hamidi et al. (2009) when adopting a risk management approach for defining insurance portfolio strategies, we analyze and illustrate a specific dynamic portfolio insurance strategy depending on the Value-at-Risk level of the covered portfolio on the French stock market. This dynamic approach is derived from the traditional and popular portfolio insurance strategy (Cf. Black and Jones, 1987 ; Black and Perold, 1992) : the so-called "Constant Proportion Portfolio Insurance" (CPPI). However, financial results produced by this strategy crucially depend upon the leverage - called the multiple - likely guaranteeing a predetermined floor value whatever the plausible market evolutions. In other words, the unconditional multiple is defined once and for all in the traditional setting. The aim of this article is to further examine an alternative to the standard CPPI method, based on the determination of a conditional multiple. In this time-varying framework, the multiple is conditionally determined in order to remain the risk exposure constant, even if it also depends upon market conditions. Furthermore, we propose to define the multiple as a function of an extended Dynamic AutoRegressive Quantile model of the Value-at-Risk (DARQ-VaR). Using a French daily stock database (CAC 40) and individual stocks in the period 1998-2008), we present the main performance and risk results of the proposed Dynamic Proportion Portfolio Insurance strategy, first on real market data and secondly on artificial bootstrapped and surrogate data. Our main conclusion strengthens the previous ones : the conditional Dynamic Strategy with Constant-risk exposure dominates most of the time the traditional Constant-asset exposure unconditional strategies.CPPI, Portfolio insurance, VaR, CAViaR, quantile regression, dynamic quantile model.
Dynamic interneuron-principal cell interplay leads to a specific pattern of in vitro ictogenesis
No full textIctal discharges induced by 4-aminopyridine in the in vitro rodent entorhinal cortex present with either low-voltage fast or sudden onset patterns. The role of interneurons in initiating low-voltage fast onset ictal discharges is well established but the processes leading to sudden onset ictal discharges remain unclear. We analysed here the participation of interneurons (n = 75) and principal cells (n = 13) in the sudden onset pattern by employing in vitro tetrode wire recordings in the entorhinal cortex of brain slices from Sprague-Dawley rats. Ictal discharges emerged from a background of frequently occurring interictal spikes that were associated to a specific interneuron/principal cell interplay. High rates of interneuron firing occurred 12 ms before interictal spike onset while principal cells fired later during low interneuron firing. In contrast, the onset of sudden ictal discharges was characterized by increased firing from principal cells 627 ms before ictal onset whereas interneurons increased their firing rates 161 ms before ictal onset. Our data show that sudden onset ictogenesis is associated with frequently occurring interictal spikes resting on the interplay between interneurons and principal cells while ictal discharges stem from enhanced principal cell firing leading to increased interneuron activity. These findings indicate that specific patterns of interactions between interneurons and principal cells shape interictal and ictal discharges with sudden onset in the rodent entorhinal cortex. We propose that specific neuronal interactions lead to the generation of distinct onset patterns in focal epileptic disorders
Hacia un campo de innovación : la mediación familiar en gerontología : análisis de la dínámica familiar en el contexto de la enfermedad de Alzheimer = Vers un champ d'innovation : la mediation familiale en gerontologie : analyse de la dynamique familiale dans le contexte de la maladie d'Alzheimer.
No full textEl trabajo efectuado en el marco de esta tesis se sitúa en la encrucijada de la
sociología de la familia, del envejecimiento, de la salud pública, de la
sicogerontología y del Derecho privado. Se basa en una metodología que utiliza
varias herramientas: análisis cuantitativo a partir de cuestionarios y análisis
cualitativo a partir de la observación, de entrevistas semi-dirigidas, grupos de
discusión y de genogramas. El trabajo de encuesta realizado en Francia
principalmente en el departamento de los Alpes-Marítimos, situado en la región
Provenza Costa Azul (PACA), ha sido conducido con familias con personas
afectadas con la enfermedad de Alzheimer y con profesionales del campo geriátrico.
Este trabajo tiene dos componenentes:
· Aspecto diagnóstico
· Aspecto de las recomendaciones
Palabras claves: Enfermedad de Alzheimer, vejez, dependencia, cuidadores
familiares, organización familiar, conflictos.
RABIÀ HAMIDI
ABSTRACT OF THESIS
TO A FIELD IN INNOVATION: FAMILY MEDIATION IN GERONTOLOGY
'' Analysis of family dynamics in the context of Alzheimer's disease "
ABSTRACT
The work done in this thesis is located at the crossing of the sociology of
family, ageing, the public health, the psychogerontologie and the private law. It is
based on a methodology that uses several tools: quantitative analysis based on
questionnaires and qualitative analysis from observation, semi-structured interviews,
focus group and genograms. The work of investigation realized in France in the
Alpes-Maritimes Department situated in the Provence-Alpes-Côte d’Azur region , was
conducted with families of people with Alzheimer's and professionals in the geriatric
field.
This work consists of two sectors :
· Diagnosis aspect
· Recommendations aspect
Keywords : Alzheimer's disease, old age, dependency, family caregivers, family
organization, conflicts
La Société civile dans les cités : engagement associatif et politisation dans des associations de quartier, C. Hamidi
No full textLes associations — l’une des composantes majeures de la société civile — sont-elles des passerelles vers la société politique ? Des écoles de démocratie ? Des lieux d’apprentissage du débat public ? Dans quelles circonstances et pour qui ? Telles sont les questions soulevées par Camille Hamidi dans son livre La Société civile dans les cités. Pour y répondre, elle a choisi de mener une enquête intensive en participant, il y a une dizaine d’années (entre 1998 et 2000), à la vie de trois associa..
Spatially-localized time dependent solutions including turbulence and their interactions in 2D Kolmogorov flow
No full textIn 2D Kolmogorov flow in small aspect ratio domains, spatially-localized solutions such as kink, traveling or time-dependent kink-antikink pars coexist. However, the conservation of the flow rate in the y direction strongly restrict combination of localized solutions and their positioning. We find that by adding a homogeneous flow U y their positioning is controlled and each of localized solutions including a spatially-localized chaos is isolated. Numerical results suggest that these isolated solutions can be elements constructing a whole flow
Characteristics of overlap region in high-Reynolds number turbulent channel flow
No full textDirect numerical simulation of the fully developed turbulent channel flows have been carried out at the Reynolds number based on the friction velocity and the channel half width, 2000, 4000 and 8000. A hybrid 10th order accurate finite difference scheme in the stream and spanwise directions, and a second-order scheme in the wall-normal direction is adapted as the spatial discretization method. We observed the plateau profiles in the indicator function corresponded to the von Karman constant. Furthermore, second peak of streamwise pre-multiplied spectra were appeared in the same wall normal height, 300 < y+ < 600, in case of Re = 4000. Nevertheless, the effects of the lager than the channel half height scale on the streamwise turbulent intensity are fixed contributions without dependence on Reynolds number. These results suggested that the new streamwise vortexes are formed between buffer layer and outer layer with increasing of Reynolds number
La 'circunstancia' de 'Herederos y Pretendientes
No full textIn June 2010, the Ortega y Gasset Foundation hosted a Conference about the “Spanish Philosophical Transition” in order to debate the book of Francisco Vázquez, La filosofía española. Herederos y Pretendientes. Una lectura sociológica (1963-1990), recently published. This paper is the author’s response to criticism raised in the Conference and to published reviews received by this book. First, the author summarized the argument of Herederos y pretendientes. Secondly he responds and takes into account the most important objections against the book’s hypothesis and methodology. Finally the author evaluates the favorable judgments received by the book and suggests the limits of the historian’s task.Fundación Ortega y Gasset-Marañó
Analog Analogies: \u3cem\u3eIntel v. Hamidi\u3c/em\u3e and the Future of Trespass to Chattels
No full textA symposium on great torts cases of the twenty-first century must include Intel Corp. v. Hamidi, the canonical case about whether unwanted e-mail spam sent to a company’s server could give rise to a trespass to chattels claim. While much has been written about Intel, in this Essay, we argue that Intel is as much of a classic for what it reveals about the old-fashioned tort as it is for its more closely examined ruling on “cybertrespass.” The dueling personal property analogies chosen by the majority and dissenting opinions in Intel reveal basic and fundamental disagreements about what sorts of conduct the traditional tort prohibits: specifically, when a plaintiff may obtain nominal damages or an injunction against a defendant’s contact with personal property when that contact does not have lasting physical effects. As we point out, this question arose in cases long before Intel and generated some discussion during the drafting of the First and Second Restatements of Torts. Now, the same question arises in Fourth Amendment law and the law of Article III standing, areas in which recent Supreme Court decisions have elevated trespass-tochattels analyses to renewed significance. Our Essay indicates the need for further development on open questions in the law of trespass to chattels, suggesting some ways that central tort-law notions like intentionality and custom might provide firmer bases for recognizing the harm in unwanted contact with things
Echoes of diversity: using maker activities to support children’s learning and empowerment
No full textFOAD HAMIDI [email protected] Postdoctoral Research Associate, Department of Information Systems Dr. Foad Hamidi is a Postdoctoral Research Associate at the Univeristy of Maryland, Baltimore County. He is interested in using digital media to facilitate creative and learning processes in intercultural settings for children and adults. He is also interested in the participatory design and evaluation of tangible and embedded systems. -- KARLA SAENZ [email protected] Instructor, Department of Design, Science, Arte and Technology Karla Saenz is a designer, artist and educator who is interested in creating opportunities for creative expression for children and adults. She is the co-director of Kopalli Arte Público. Universidad Iberoamericana Mexico City, Mexico -- MELANIE BALJKO [email protected] Lassonde School of Engineering Dr. Melanie Baljko is an Associate Professor in Electrical Engineering and Computer Science at York University in Toronto and also a member of the graduate programs in Science and Technology Studies and Critical Disability Studies. She leads a research lab and a critical technology practice that focuses on assistive and enabling technologies, on technologies that mediate learning and communication, and on their ecosystems of production and use.Interactive digital media are emerging as new tools for learning and self-expression for children. The development of easy-to-use and affordable electronic hardware and software is making it possible to engage children in low-income settings in personally meaningful digital design projects. We describe a two-day interdisciplinary workshop in Oaxaca, Mexico, where we used a maker process to create interactive digital artifacts with 16 children. We incorporated local folk art traditions in the projects that consisted of a series of alebrijes hábitats and a sonic mural installation. We explored the possibility of supporting psychological empowerment and learning through digital making for the children.Los medios digitales interactivos se están convirtiendo en nuevas herramientas para el aprendizaje y la autoexpresión de los niños. El desarrollo de hardware y software electrónicos asequibles en costo y uso, hace posible la participación de niños y niñas de escasos recursos, en proyectos de diseño digital personalmente significativos. Se describe en el siguiente articulo un taller interdisciplinario de dos días impartido en Oaxaca, México, donde fue usado un proceso creativo para crear artefactos digitales interactivos con la participación de 16 niños. Fueron incorporadas las tradiciones locales de arte popular en los proyectos que consistieron en una serie de alebrijes, sus hábitats imaginarios y una instalación mural sónica. Exploramos la posibilidad de apoyar el empoderamiento psicológico y el aprendizaje a través de la creación digital para niños y niñas
Analog Analogies: \u3cem\u3eIntel v. Hamidi\u3c/em\u3e and the Future of Trespass to Chattels
No full textA symposium on great torts cases of the twenty-first century must include Intel Corp. v. Hamidi, the canonical case about whether unwanted e-mail spam sent to a company’s server could give rise to a trespass to chattels claim. While much has been written about Intel, in this Essay, we argue that Intel is as much of a classic for what it reveals about the old-fashioned tort as it is for its more closely examined ruling on “cybertrespass.” The dueling personal property analogies chosen by the majority and dissenting opinions in Intel reveal basic and fundamental disagreements about what sorts of conduct the traditional tort prohibits: specifically, when a plaintiff may obtain nominal damages or an injunction against a defendant’s contact with personal property when that contact does not have lasting physical effects. As we point out, this question arose in cases long before Intel and generated some discussion during the drafting of the First and Second Restatements of Torts. Now, the same question arises in Fourth Amendment law and the law of Article III standing, areas in which recent Supreme Court decisions have elevated trespass-tochattels analyses to renewed significance. Our Essay indicates the need for further development on open questions in the law of trespass to chattels, suggesting some ways that central tort-law notions like intentionality and custom might provide firmer bases for recognizing the harm in unwanted contact with things
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