Direct Photodetachment of F‾ by mid-infrared few-cycle femtosecond laser pulses

The recent adiabatic saddle-point approach of Shearer et al. [ Phys. Rev. A 84 033409 (2011)] is extended to multiphoton detachment of negative ions with outer p-state electrons. This theory is applied to investigate the strong-field photodetachment dynamics of F- ions exposed to few-cycle femtosecond laser pulses, without taking into account the rescattering mechanism. Numerical calculations are considered for mid-infrared laser wavelengths of 1300 and 1800 nm at laser intensities of 7.7 × 1012, 1.1 × 1013, and 1.3 × 1013 W/cm2. Two-dimensional momenta saddle-point spectra exhibit a distinct distribution in the shape of a “smile” in the complex-time plane. Electron momentum distribution maps of direct electrons are investigated. These produce a distinct pattern of above-threshold detachment (ATD) concentric rings due to constructive and destructive quantum interference of electrons detached from their parent ions. Probability detachment distributions presented, capturing the influence of saturation effects that are found to become more significant with increasing laser intensity at a fixed wavelength. ATD photoangular distributions as functions of laser intensity and wavelength near channel closings are also investigated and found to be sensitive to initial-state symmetry. Nonmonotonic structures observed in the ejected photoelectron energy spectra are attributed to interference effects from coherent electronic wave packets. Additionally the profiles of all the photoelectron emission spectra show strong dependence on the carrier-envelope phase, indicating that it is a reliable parameter for characterizing the wave form of the pulse.

Aesthetic Perceptions - Is There a Difference?

Introduction: In recent times, the demand for aesthetic dentistry has increased, with patients presenting for treatment expecting an improvement in their aesthetics. Therefore, it is increasingly important for the dental profession to appreciate perceptions of dental aesthetics in order to provide a patient-centred service.

Objectives: The aim of this study is to quantify perceptions of aesthetics using a cross-sectional survey design. The hypotheses being tested were that differences exist in aesthetic perceptions of 1) dentists and dental students, 2) different age ranges and 3) gender.

Methods: A questionnaire was distributed to dental staff and students in the Cork University Dental School and Hospital. The questionnaire sought information relating to aesthetic perceptions by asking participants to compare photographs of smiles.

Results: 100 questionnaires were returned. It was found that differences existed in perceptions of dentists and dental students when certain aspects of a smile were evaluated, in particular when a minor flaw was present in a smile in addition to the major flaw being tested. Assuming that flaws were detected, more dental students (34%) than dentists (26%) were found to prioritise colour above more subtle flaws, such as a centreline shift. However, most results between the two groups are comparable in terms of their prioritising of importance of particular aspects of a smile, with no large significant differences.

Conclusion: Differences exist in aesthetic perceptions of dentists and dental students, especially with regard to tooth colour.

Margaret Glassford fonds, 1941, 1951, 1961, 1971, 1973-1975, 1977-1984, 1986-2000, 2002, 2005, n.d.

Margaret was an only child who grew up on a farm just east of Cayuga, Ontario. After high school, Margaret attended Hamilton Teacher’s College and took a position with Grantham Public School Board and taught at Power Glen school. Margaret was married in 1962 and had 2 children, a daughter and a son in 1963 and 1964, respectively. Margaret left her teaching job to raise her children. Margaret was very creative and artistic and during this time, focused on these talents, which included painting, graphic arts and sewing. Margaret was also an accomplished pianist. In her 40’s, Margaret enrolled at Brock University and in 1989 obtained a Honors Bachelor of Arts degree with First-Class Honors in Sociology. In partial fulfillment of her Honors B.A. she completed her thesis that is entitled ; The State and Liberal Feminism: The Ontario Government’s “Business Ownership For Women Program”. While living in St. Catharines, Margaret attended York University and graduated with a Master of Arts in Sociology in 1992 where her studies focused on women’s issues. Margaret received a scholarship from York University and was a teaching assistant. Margaret stayed on at York University and completed her academic requirements for a Doctorate degree in Sociology. Her dissertation was on self employed women in St. Catharines at the beginning of WWII -- not the” Rosie the Riveters” who took over jobs formerly held by men who had to go off to fight World War II, but women who ran their own businesses when that was still unusual. Margaret completed the research for her thesis but did not complete her written thesis as she made a difficult decision to put her academic work on hold in the mid-1990’s and she returned to her love for the arts, although she always remained a voracious reader and interested in women’s issues. In the last decade of her life, she took up quilting with a passion, which she referred to as fabric arts. Margaret loved colour and being non-traditional. Margaret had been a quilting instructor at the Flemington College for Fine Arts in Haliburton. In 1997, Margaret founded Project Smile in the St. Catharines region, a non-profit group who make quilts for children with cancer. Margaret was also the President of the Niagara Heritage Quilters’ Guild in 2006-2007 and was very involved with the Local Council of Women.

Letter - E.C. Schmon to Arthur A. Schmon, 15 February 1917

A brief note to Arthur Schmon that reads: " February fifteenth. Dear, This is to let you see that I am not neglecting my duties as a member of the "cheer committee". Remember that the only thing that never goes out of style is a smile, so keep on wearing one. Affectionately, Lessie."

Niagara Falls, U.S.A.

The image is described as "(8) Nature's Everlasting Smile, Niagara Falls, U.S.A."

Asymmetric Smiles, Leverage Effects and Structural Parameters.

In this paper, we characterize the asymmetries of the smile through multiple leverage effects in a stochastic dynamic asset pricing framework. The dependence between price movements and future volatility is introduced through a set of latent state variables. These latent variables can capture not only the volatility risk and the interest rate risk which potentially affect option prices, but also any kind of correlation risk and jump risk. The standard financial leverage effect is produced by a cross-correlation effect between the state variables which enter into the stochastic volatility process of the stock price and the stock price process itself. However, we provide a more general framework where asymmetric implied volatility curves result from any source of instantaneous correlation between the state variables and either the return on the stock or the stochastic discount factor. In order to draw the shapes of the implied volatility curves generated by a model with latent variables, we specify an equilibrium-based stochastic discount factor with time non-separable preferences. When we calibrate this model to empirically reasonable values of the parameters, we are able to reproduce the various types of implied volatility curves inferred from option market data.

Empirical Assessment of an Intertemporal Option Pricing Model with Latent variables

This paper assesses the empirical performance of an intertemporal option pricing model with latent variables which generalizes the Hull-White stochastic volatility formula. Using this generalized formula in an ad-hoc fashion to extract two implicit parameters and forecast next day S&P 500 option prices, we obtain similar pricing errors than with implied volatility alone as in the Hull-White case. When we specialize this model to an equilibrium recursive utility model, we show through simulations that option prices are more informative than stock prices about the structural parameters of the model. We also show that a simple method of moments with a panel of option prices provides good estimates of the parameters of the model. This lays the ground for an empirical assessment of this equilibrium model with S&P 500 option prices in terms of pricing errors.

Risk Aversion, Intertemporal Substitution, and Option Pricing

This paper develops a general stochastic framework and an equilibrium asset pricing model that make clear how attitudes towards intertemporal substitution and risk matter for option pricing. In particular, we show under which statistical conditions option pricing formulas are not preference-free, in other words, when preferences are not hidden in the stock and bond prices as they are in the standard Black and Scholes (BS) or Hull and White (HW) pricing formulas. The dependence of option prices on preference parameters comes from several instantaneous causality effects such as the so-called leverage effect. We also emphasize that the most standard asset pricing models (CAPM for the stock and BS or HW preference-free option pricing) are valid under the same stochastic setting (typically the absence of leverage effect), regardless of preference parameter values. Even though we propose a general non-preference-free option pricing formula, we always keep in mind that the BS formula is dominant both as a theoretical reference model and as a tool for practitioners. Another contribution of the paper is to characterize why the BS formula is such a benchmark. We show that, as soon as we are ready to accept a basic property of option prices, namely their homogeneity of degree one with respect to the pair formed by the underlying stock price and the strike price, the necessary statistical hypotheses for homogeneity provide BS-shaped option prices in equilibrium. This BS-shaped option-pricing formula allows us to derive interesting characterizations of the volatility smile, that is, the pattern of BS implicit volatilities as a function of the option moneyness. First, the asymmetry of the smile is shown to be equivalent to a particular form of asymmetry of the equivalent martingale measure. Second, this asymmetry appears precisely when there is either a premium on an instantaneous interest rate risk or on a generalized leverage effect or both, in other words, whenever the option pricing formula is not preference-free. Therefore, the main conclusion of our analysis for practitioners should be that an asymmetric smile is indicative of the relevance of preference parameters to price options.

Analyse de l'influence des paramètres esthétiques sur l’attrait du sourire tel que perçu par des non-experts : étude transversale exploratoire

Malgré l’abondance d’information concernant la dentisterie esthétique, les évidences scientifiques à son sujet sont rarissimes. Ainsi, cette recherche a pour premier but d’accroître ces évidences en faisant la lumière sur les paramètres esthétiques et leur influence auprès de l’appréciation générale du sourire, tel que perçu par des sujets non-experts. Une invitation à répondre à un questionnaire autoadministré anonyme a été envoyée à la communauté de l’Université de Montréal par courrier électronique. 467 personnes ont accepté de répondre au questionnaire, toutefois seulement 263 ont terminé l'opération. L’analyse des données démontre que le seul critère esthétique objectif ayant une influence statistiquement significative sur l’appréciation générale est « l’arrangement des dents » (p = .028). Les dents versées diminuent significativement l’attrait général par rapport à des dents droites (p = .012) ou chevauchées (p = .009). Par contre, en corrélant ces données avec les convictions des sujets, « l’angulation de la médiane dentaire supérieure » ainsi que « l’inclinaison du plan incisif » présentent aussi des différences statistiquement significatives. « L’état d’usure des dents » et leur « position » sont les éléments, parmi le vocabulaire suggéré, les plus importants pour l’attrait du sourire aux yeux des patients. Avec les limitations de cette étude, on peut conclure que (1) « l’arrangement des dents », « l’angulation de la médiane dentaire supérieure » et « l’inclinaison du plan incisif » influencent de manière statistiquement significative l’appréciation générale du sourire. (2) Parmi les critères objectifs étudiés, « l'arrangement des dents » a la plus forte influence sur l’appréciation générale d’un sourire. (3) Une corrélation statistiquement significative entre les deux séquences d’évaluation et la faible variance intrasujet indiquent que l’appréciation générale d’un sourire est une action réflexe basée, entre autres, sur des paramètres morphologiques. Application pratique : Les résultats de cette étude insinuent que les traitements visant à corriger l’alignement, l’usure des dents et ceux visant à blanchir les dents d’un individu sont susceptibles d’augmenter l’attrait de son sourire tel que perçu par des sujets non-experts.

Learning-Based Approach to Real Time Tracking and Analysis of Faces

This paper describes a trainable system capable of tracking faces and facialsfeatures like eyes and nostrils and estimating basic mouth features such as sdegrees of openness and smile in real time. In developing this system, we have addressed the twin issues of image representation and algorithms for learning. We have used the invariance properties of image representations based on Haar wavelets to robustly capture various facial features. Similarly, unlike previous approaches this system is entirely trained using examples and does not rely on a priori (hand-crafted) models of facial features based on optical flow or facial musculature. The system works in several stages that begin with face detection, followed by localization of facial features and estimation of mouth parameters. Each of these stages is formulated as a problem in supervised learning from examples. We apply the new and robust technique of support vector machines (SVM) for classification in the stage of skin segmentation, face detection and eye detection. Estimation of mouth parameters is modeled as a regression from a sparse subset of coefficients (basis functions) of an overcomplete dictionary of Haar wavelets.

Anorí, lo dulce y amargo de la sustitución de cultivos

Anorí es un pueblo pujante de Antioquia que sustituye su forma de vida; intenta pasar de lo ilegal a lo legal, de la violencia a la paz y de la coca al cacao. Sustituir para la construcción de conciencias es la esencia del programa de la Gobernación de Antioquia y de la Oficina de Naciones Unidas contra la Droga y el Delito. Este proyecto empezó en el 2006 e involucró a 100 familias y, aunque la idea era sumar experiencias, sucedió lo contrario. Hoy, solo 56 grupos son beneficiarios de la iniciativa. Sin embargo, ya está a la venta la chocolatina Anorí, producto de los nuevos cultivos de cacao, capaces de devolverle la sonrisa a la población de este municipio, que tantas veces ha sido censurada por el miedo.

Marimba, rumba y peregrinación en el pacífico colombiano

Las culturas afrocolombianas recogen historias culturales muy valiosas. Guapi y Timbiquí, dos municipios del Cauca, azotados por el conflicto armado, no han dejado de mostrar su sonrisa y su devoción a través de sus fiesta patronales y su constante alegría.

Distribución hiperbólica generalizada: una aplicación en la selección de portafolios y en la cuantificación de medidas de riesgo de mercado

En este trabajo se implementa una metodología para incluir momentos de orden superior en la selección de portafolios, haciendo uso de la Distribución Hiperbólica Generalizada, para posteriormente hacer un análisis comparativo frente al modelo de Markowitz.

Option pricing in market models driven by telegraph processes with jumps

Esta tesis está dividida en dos partes: en la primera parte se presentan y estudian los procesos telegráficos, los procesos de Poisson con compensador telegráfico y los procesos telegráficos con saltos. El estudio presentado en esta primera parte incluye el cálculo de las distribuciones de cada proceso, las medias y varianzas, así como las funciones generadoras de momentos entre otras propiedades. Utilizando estas propiedades en la segunda parte se estudian los modelos de valoración de opciones basados en procesos telegráficos con saltos. En esta parte se da una descripción de cómo calcular las medidas neutrales al riesgo, se encuentra la condición de no arbitraje en este tipo de modelos y por último se calcula el precio de las opciones Europeas de compra y venta.

The Influence of Gender and Facial Appearance on Voting Practices

Women’s faces tend to naturally retain more neonate features than men. These features, such as a greater eye height, a smaller nose area, and a wider smile, would cause women to have more immature faces than males. Interestingly, women who have these facial features are often perceived as more attractive than women with mature facial features. These findings imply that women would be judged less competent than men, and that immature-faced women would be perceived as less competent and more attractive than mature-faced females. Given the direction of political leadership in our country, this has interesting implications for females that are vying for leadership positions. Thus, our study examined the effects of both candidate gender and facial features on voting likelihood, and perceptions of attractiveness and competence, by pairing pictures with neutral party platforms.