The voiced labiodental allophone [v] of the phoneme /b in the spanish of Concepción (Chile): an exploration study

La existencia de un alófono labiodental sonoro [v] del fonema /b/ en la lengua castellana es ampliamente rechazada, hasta tal punto que a menudo la única manera de rastrear este fono es a través de su omisión de las descripciones del sistema fonético-fonológico del español. En el caso del castellano de Chile, sin embargo, han surgido en las últimas dos décadas por lo menos tres investigaciones que rompen con este consenso. El presente artículo da cuenta de una investigación exploratoria de las realizaciones del fonema /b/ en el español de jóvenes adultos de la provincia de Concepción, Chile. La hipótesis de la existencia de un alófono labiodental sonoro [v] de /b/ se constata, y se procede a analizar su frecuencia y distribución en los distintos entornos fonéticos. Se determina que el 59,5% de las realizaciones de /b/ corresponde al labiodental sonoro [v], una cifra sustancialmente más alta de la que predice la literatura. Además, se determina que [v] es el alófono más frecuente en 11 de los 20 entornos anteriores y en 16 de los 19 entornos posteriores que se analizaron, y que la representación ortográfica de este fonema no incide en la selección de sus alófonos.The existence in Spanish of a voiced labiodental allophone [v] of the phoneme /b/ is widely rejected — so much so, in fact, that often the only way to trace this phone is through its absence from descriptions of the Spanish phonetic-phonological system. In the case of Chilean Spanish, however, at least three exceptions to this consensus have emerged in the last two decades. This article presents the results of a pilot study of the allophones of the phoneme /b/ in the Spanish of young adults in the province of Concepción, Chile. The hypothesis that the phoneme /b/ has a voiced labiodental allophone [v] is confirmed, and the frequency and distribution of this allophone in different phonetic environments are analyzed. The analysis shows that [v] accounts for 59.5% of all tokens of /b/, a substantially higher number than the literature predicts. It further shows that [v] is the most frequent allophone in 11 of 20 anterior phonetic environments and 16 of 19 posterior environments, and that the orthographic representation of this phoneme does not influence the selection of allophones

Valuing Pilot Project Investments in Incomplete Markets : A Compound Option Approach

We introduce a general framework to value pilot project investments under the presence of both, market and technical uncertainty. The model generalizes different settings introduced previously in the literature. By distinguishing between the pilot and the commercial stages of the project we are able to frame the problem as a compound perpetual Bermudan option. We work on an incomplete market setting where market uncertainty is spanned by tradable assets and technical uncertainty is private to the firm. The value of these investment opportunities as well as the optimal exercise problem are solved by approximate dynamic programming techniques. We prove the convergence of our algorithm and derive a theoretical bound on how the errors compound as the number of stages of the compound option is increased. Furthermore, we show some numerical results and provide an economic interpretation of the model dynamicsreal options, dynamic programming, incomplete markets

Importance Sampling for multi-constraints rare event probability

Improving Importance Sampling estimators for rare event probabilities requires sharp approx- imations of the optimal density leading to a nearly zero-variance estimator. This paper presents a new way to handle the estimation of the probability of a rare event defined as a finite intersection of subset. We provide a sharp approximation of the density of long runs of a random walk condi- tioned by multiples constraints, each of them defined by an average of a function of its summands as their number tends to infinity.Comment: Conference pape

Efficient simulation of density and probability of large deviations of sum of random vectors using saddle point representations

We consider the problem of efficient simulation estimation of the density function at the tails, and the probability of large deviations for a sum of independent, identically distributed, light-tailed and non-lattice random vectors. The latter problem besides being of independent interest, also forms a building block for more complex rare event problems that arise, for instance, in queueing and financial credit risk modelling. It has been extensively studied in literature where state independent exponential twisting based importance sampling has been shown to be asymptotically efficient and a more nuanced state dependent exponential twisting has been shown to have a stronger bounded relative error property. We exploit the saddle-point based representations that exist for these rare quantities, which rely on inverting the characteristic functions of the underlying random vectors. These representations reduce the rare event estimation problem to evaluating certain integrals, which may via importance sampling be represented as expectations. Further, it is easy to identify and approximate the zero-variance importance sampling distribution to estimate these integrals. We identify such importance sampling measures and show that they possess the asymptotically vanishing relative error property that is stronger than the bounded relative error property. To illustrate the broader applicability of the proposed methodology, we extend it to similarly efficiently estimate the practically important expected overshoot of sums of iid random variables

Evaluating Response to High-Dose 13.3 mg/24 h Rivastigmine Patch in Patients with Severe Alzheimer's Disease

AIMS: To identify factors predicting improvement/stabilization on the Alzheimer's Disease Cooperative Study-Clinical Global Impression of Change (ADCS-CGIC) and investigate whether early treatment responses can predict long-term outcomes, during a trial of 13.3 mg/24 h versus 4.6 mg/24 h rivastigmine patch in patients with severe Alzheimer's disease (AD). METHODS: Logistic regression was used to relate Week 24 ADCS-CGIC score to potential baseline predictors. Additional analyses based on receiver-operating characteristic curves were performed using Week 8/16 ADCS-CGIC scores to predict response (13.3 mg/24 h patch) at Week 24. ADCS-CGIC score of (1) 1-3 = "improvement," (2) 1-4 = "improvement or no change". RESULTS: "Treatment" (13.3 mg/24 h patch) and increased age were significant predictors of "improvement" (P = 0.01 and P = 0.003, respectively), and "treatment" (P = 0.001), increased age (P = 0.002), and prior AD treatment (P = 0.03) for "improvement or no change". At Week 8 and 16, ADCS-CGIC scores of 4 and 5 were optimal thresholds in predicting "improvement," and "improvement or no change," respectively, at Week 24. CONCLUSIONS: A significant therapeutic effect of high-dose rivastigmine patch on ADCS-CGIC response was observed. The 13.3 mg/24 h patch was identified as a predictor of "improvement" or "improvement or no change". Patients with minimal worsening/improvement/no change after treatment initiation may be more likely to respond following long-term therapy

Triangular buckling patterns of twisted inextensible strips

When twisting a strip of paper or acetate under high longitudinal tension, one observes, at some critical load, a buckling of the strip into a regular triangular pattern. Very similar triangular facets have recently been observed in solutions to a new set of geometrically-exact equations describing the equilibrium shape of thin inextensible elastic strips. Here we formulate a modified boundary-value problem for these equations and construct post-buckling solutions in good agreement with the observed pattern in twisted strips. We also study the force-extension and moment-twist behaviour of these strips by varying the mode number n of triangular facets

Minimal resonances in annular non-Euclidean strips

Differential growth processes play a prominent role in shaping leaves and biological tissues. Using both analytical and numerical calculations, we consider the shapes of closed, elastic strips which have been subjected to an inhomogeneous pattern of swelling. The stretching and bending energies of a closed strip are frustrated by compatibility constraints between the curvatures and metric of the strip. To analyze this frustration, we study the class of "conical" closed strips with a prescribed metric tensor on their center line. The resulting strip shapes can be classified according to their number of wrinkles and the prescribed pattern of swelling. We use this class of strips as a variational ansatz to obtain the minimal energy shapes of closed strips and find excellent agreement with the results of a numerical bead-spring model. Within this class of strips, we derive a condition under which a strip can have vanishing mean curvature along the center line.Comment: 14 pages, 13 figures. Published version. Updated references and added 2 figure

« High-tech, High-touch » Reconstruire de l'humain dans les entreprises à fort contenu technologique

Plus nous communiquons, plus notre organisation sera efficace et plus les hommes et les femmes seront performants. Du moins, est-ce ce que nous avons toujours pensé. D'où, pour partie, cette prolifération des nouvelles technologies de l'information et de la communication (NTIC) au cœur même des entreprises, dont Internet est l'aboutissement. Mais si les NTIC ambit ionnent la diffusion du savoir et le partage des connaissances, beaucoup d'analystes – au premier rang desquels Vastel (1999), Saramago (1999), Barber (1999) – se demandent si les NTIC ne viennent pas de dépasser leur état optimum et si cette « nouvelle idéologie » du « tout NTIC » n'exerce pas, désormais, sur les hommes et les femmes, une authentique oppression (Ramonet, 1999). Pour « faire contrepoids » à cette oppression, les hommes et les femmes développent une résistance dont le but est de « reconstruire de l'humain » (Roche, 1997 et Sadowsky, 1999). Loin de contrecarrer cette résistance, le manager moderne, parce qu'il comprend que celle -ci concourt à rendre les individus « mieux dans leur tête » et donc plus performants dans leurs actions, doit apprendre, sous certaines conditions, à encourager, pour les utiliser, certains de ses développements.Nouvelles technologies; résistances; communication formelle; communication informelle; communities of practice