Evaluation of errors in alpine skiing video analysis

INTRODUCTION: Video records are widely used to analyze performance in alpine skiing at professional or amateur level. Parts of these analyses require the labeling of some movements (i.e. determining when specific events occur). If differences among coaches and differences for the same coach between different dates are expected, they have never been quantified. Moreover, knowing these differences is essential to determine which parameters reliable should be used. This study aimed to quantify the precision and the repeatability for alpine skiing coaches of various levels, as it is done in other fields (Koo et al, 2005). METHODS: A software similar to commercialized products was designed to allow video analyses. 15 coaches divided into 3 groups (5 amateur coaches (G1), 5 professional instructors (G2) and 5 semi-professional coaches (G3)) were enrolled. They were asked to label 15 timing parameters (TP) according to the Swiss ski manual (Terribilini et al, 2001) for each curve. TP included phases (initiation, steering I-II), body and ski movements (e.g. rotation, weighting, extension, balance). Three video sequences sampled at 25 Hz were used and one curve per video was labeled. The first video was used to familiarize the analyzer to the software. The two other videos, corresponding to slalom and giant slalom, were considered for the analysis. G1 realized twice the analysis (A1 and A2) at different dates and TP were randomized between both analyses. Reference TP were considered as the median of G2 and G3 at A1. The precision was defined as the RMS difference between individual TP and reference TP, whereas the repeatability was calculated as the RMS difference between individual TP at A1 and at A2. RESULTS AND DISCUSSION: For G1, G2 and G3, a precision of +/-5.6 frames, +/-3.0 and +/-2.0 frames, was respectively obtained. These results showed that G2 was more precise than G1, and G3 more precise than G2, were in accordance with group levels. The repeatability for G1 was +/-3.1 frames. Furthermore, differences among TP precision were observed, considering G2 and G3, with largest differences of +/-5.9 frames for "body counter rotation movement in steering phase II", and of 0.8 frame for "ski unweighting in initiation phase". CONCLUSION: This study quantified coach ability to label video in term of precision and repeatability. The best precision was obtained for G3 and was of +/-0.08s, which corresponds to +/-6.5% of the curve cycle. Regarding the repeatability, we obtained a result of +/-0.12s for G1, corresponding to +/-12% of the curve cycle. The repeatability of G2 and G3 are expected to be lower than the precision of G1 and the corresponding repeatability will be assessed soon. In conclusion, our results indicate that the labeling of video records is reliable for some TP, whereas caution is required for others. REFERENCES Koo S, Gold MD, Andriacchi TP. (2005). Osteoarthritis, 13, 782-789. Terribilini M, et al. (2001). Swiss Ski manual, 29-46. IASS, Lucerne.

Advanced optical microscopies for materials: new trends

This article summarizes the new trends of Optical Microscopy applied to Materials, with examples of applications that illustrate the capabilities of thetechnique.

The quest for blood pressure reference values in children

Do we need country-specific blood pressure reference values for children? This question will sound weird for clinicians caring for adult hypertensive patients or researchers working in the domain of adult hypertension. Indeed, there are no country-specific reference values for adults. This contrasts with hypertension in children, for whom there is an increasing number of published sets of country-specific reference values [1-5].

How important are interview methods and questionnaire designs in research on self-reported juvenile delinquency? An experimental comparison of internet vs. paper-and-pencil questionnaires and different definitions of the reference period

There has been relatively little change over recent decades in the methods used in research on self-reported delinquency. Face-to-face interviews and selfadministered interviews in the classroom are still the predominant alternatives envisaged. New methods have been brought into the picture by recent computer technology, the Internet, and an increasing availability of computer equipment and Internet access in schools. In the autumn of 2004, a controlled experiment was conducted with 1,203 students in Lausanne (Switzerland), where "paper-and-pencil" questionnaires were compared with computer-assisted interviews through the Internet. The experiment included a test of two different definitions of the (same) reference period. After the introductory question ("Did you ever..."), students were asked how many times they had done it (or experienced it), if ever, "over the last 12 months" or "since the October 2003 vacation". Few significant differences were found between the results obtained by the two methods and for the two definitions of the reference period, in the answers concerning victimisation, self-reported delinquency, drug use, failure to respond (missing data). Students were found to be more motivated to respond through the Internet, take less time for filling out the questionnaire, and were apparently more confident of privacy, while the school principals were less reluctant to allow classes to be interviewed through the Internet. The Internet method also involves considerable cost reductions, which is a critical advantage if self-reported delinquency surveys are to become a routinely applied method of evaluation, particularly so in countries with limited resources. On balance, the Internet may be instrumental in making research on self-reported delinquency far more feasible in situations where limited resources so far have prevented its implementation.

Insecticidal, repellent, antimicrobial activity and phytotoxicity of essential oils: With special reference to limonene and its suitability for control of insect pests : Review

Selostus: Monoterpeenit kasvinsuojelussa: erityisesti limoneenin vaikutus eri eliöryhmiin

Magnetism of isolated Mn12 single-molecule magnets detected by magnetic circular dichroism: Observation of spin tunneling with a magneto-optical technique

We report magnetic and magneto-optical measurements of two Mn12 single-molecule magnet derivatives isolated in organic glasses. Field-dependent magnetic circular dichroism (MCD) intensity curves (hysteresis cycles) are found to be essentially identical to superconducting quantum interference device magnetization results and provide experimental evidence for the potential of the optical technique for magnetic characterization. Optical observation of magnetic tunneling has been achieved by studying the decay of the MCD signal at weak applied magnetic field

Simple holographic polarogram

A new technique capable of obtaining quantitative values of the rotation angle of the polarization vector by using holography is presented. This is a two-stage holographic process; during the recording stage a hologram of the object of interest is obtained. The reference beam is composed of two beams that form a small angle between them and keep their polarization states at right angles to each other. In the reconstruction stage of the hologram, two images from the hologram are obtained along two different angles. As a result of the interference between these two images, a set of parallel fringes is formed at the image plane. The fringe contrast on the reconstruction is related to the angle of the polarization vector of the light at each position on the image plane. Measurements of the rotation of the polarization angle of a fraction of a degree were obtained. The main application of this technique is in the study of transient phenomena, where single-shot measurements are the only means of obtaining reliable data.

Surface reconstruction from microscopic images in optical lithography.

This paper presents a method to reconstruct 3D surfaces of silicon wafers from 2D images of printed circuits taken with a scanning electron microscope. Our reconstruction method combines the physical model of the optical acquisition system with prior knowledge about the shapes of the patterns in the circuit; the result is a shape-from-shading technique with a shape prior. The reconstruction of the surface is formulated as an optimization problem with an objective functional that combines a data-fidelity term on the microscopic image with two prior terms on the surface. The data term models the acquisition system through the irradiance equation characteristic of the microscope; the first prior is a smoothness penalty on the reconstructed surface, and the second prior constrains the shape of the surface to agree with the expected shape of the pattern in the circuit. In order to account for the variability of the manufacturing process, this second prior includes a deformation field that allows a nonlinear elastic deformation between the expected pattern and the reconstructed surface. As a result, the minimization problem has two unknowns, and the reconstruction method provides two outputs: 1) a reconstructed surface and 2) a deformation field. The reconstructed surface is derived from the shading observed in the image and the prior knowledge about the pattern in the circuit, while the deformation field produces a mapping between the expected shape and the reconstructed surface that provides a measure of deviation between the circuit design models and the real manufacturing process.

La salut reproductiva de la dona immigrant: una anàlisi des de la influència cultural

El progressiu increment del flux migratori en els darrers anys a Catalunya genera un major percentatge de dones en estat fèrtil que requereixen d’una atenció vinculada a la seva salut reproductiva. D’aquesta manera, els professionals sanitaris es veuen sotmesos a treballar sota una diversitat cultural que moltes vegades genera un “xoc intercultural” dificultant la relació assistencial entre professional i usuari. Per aquest motiu, el següent estudi pretén donar una aproximació de la influència cultural de la dona immigrant (marroquina i subsahariana) en quatre àmbits: embaràs, part, post-part i maternitat.Hipòtesis: S’identifiquen necessitats bàsiques assistencials no resoltes satisfactòriament en el grup de dones immigrants (marroquines i subsaharianes) en el període del part, puerperi immediat i intermedi, a més d’un impacte intercultural associat.Objectiu principal: Conèixer les vivències, percepcions i conductes de les dones marroquines i subsaharianes en l’embaràs, el part, el post-part, la maternitat dins el seu marc cultural i com influeixen en l’atenció sanitària del nostre país.Material i mètodes: S’ha realitzat un estudi de disseny mixt. Per una banda s’ha disposat d’una metodologia qualitativa descriptiva que utilitza la teoria fonamentada “Grounded Theory” com a instrument metodològic, i per l’altra, s’ha optat per una metodologia quantitativa per analitzar les dades clíniques i epidemiològiques de gestants immigrants que havien donat a llum al Servei d’Obstetrícia-Sala de Parts de l’Hospital Sta. Caterina (Girona), durant el període comprès entre el mes de novembre de 2012 i gener de 2013.La recollida de dades s’ha realitzat sota una entrevista semiestructurada i una observació participant com a instruments qualitatius, i el suport del “carnet de l’embaràs” i la “història obstètrica” de cada dona per elaborar l’estudi quantitatiu. Pel que fa a l’anàlisi de les dades en l’estudi qualitatiu s’ha seguit el procés analític plantejat per la Teoria fonamentada i en el cas de l’estudi quantitatiu, s’ha comptatamb el suport d’una tesi doctoral per comparar els resultats amb els de les dones autòctones, dels quals fa referència la tesi.Resultats: En l’estudi qualitatiu, s’han trobat especificitats culturals en relació a la percepció del part, desenvolupament del part ( a nivell conductual), implicació en el post-part, valoració de l’atenció sanitària rebuda i el concepte de maternitat. Pel que fa a l’estudi quantitatiu comparatiu, s’han indentificat diferències entre el col·lectiu de la mostra estudiada i les dones autòctones referent als antecedents obstètrics i paritat, al control gestacional i al desenvolupament del part ( a nivell fisiològic)

Line search multilevel optimization as computational methods for dense optical flow

We evaluate the performance of different optimization techniques developed in the context of optical flow computation with different variational models. In particular, based on truncated Newton methods (TN) that have been an effective approach for large-scale unconstrained optimization, we de- velop the use of efficient multilevel schemes for computing the optical flow. More precisely, we evaluate the performance of a standard unidirectional mul- tilevel algorithm - called multiresolution optimization (MR/OPT), to a bidrec- tional multilevel algorithm - called full multigrid optimization (FMG/OPT). The FMG/OPT algorithm treats the coarse grid correction as an optimiza- tion search direction and eventually scales it using a line search. Experimental results on different image sequences using four models of optical flow com- putation show that the FMG/OPT algorithm outperforms both the TN and MR/OPT algorithms in terms of the computational work and the quality of the optical flow estimation.

New reference tables and user-friendly Internet application for predicted heart weights.

BACKGROUND: Knowledge of normal heart weight ranges is important information for pathologists. Comparing the measured heart weight to reference values is one of the key elements used to determine if the heart is pathological, as heart weight increases in many cardiac pathologies. The current reference tables are old and in need of an update. AIMS: The purposes of this study are to establish new reference tables for normal heart weights in the local population and to determine the best predictive factor for normal heart weight. We also aim to provide technical support to calculate the predictive normal heart weight. METHODS: The reference values are based on retrospective analysis of adult Caucasian autopsy cases without any obvious pathology that were collected at the University Centre of Legal Medicine in Lausanne from 2007 to 2011. We selected 288 cases. The mean age was 39.2 years. There were 118 men and 170 women. Regression analyses were performed to assess the relationship of heart weight to body weight, body height, body mass index (BMI) and body surface area (BSA). RESULTS: The heart weight increased along with an increase in all the parameters studied. The mean heart weight was greater in men than in women at a similar body weight. BSA was determined to be the best predictor for normal heart weight. New reference tables for predicted heart weights are presented as a web application that enable the comparison of heart weights observed at autopsy with the reference values. CONCLUSIONS: The reference tables for heart weight and other organs should be systematically updated and adapted for the local population. Web access and smartphone applications for the predicted heart weight represent important investigational tools.

Composition, nanostructure, and optical properties of silver and silver-copper lusters

Lusters are composite thin layers of coinage metal nanoparticles in glass displaying peculiar optical properties and obtained by a process involving ionic exchange, diffusion, and crystallization. In particular, the origin of the high reflectance (golden-shine) shown by those layers has been subject of some discussion. It has been attributed to either the presence of larger particles, thinner multiple layers or higher volume fraction of nanoparticles. The object of this paper is to clarify this for which a set of laboratory designed lusters are analysed by Rutherford backscattering spectroscopy, transmission electron microscopy, x-ray diffraction, and ultraviolet-visible spectroscopy. Model calculations and numerical simulations using the finite difference time domain method were also performed to evaluate the optical properties. Finally, the correlation between synthesis conditions, nanostructure, and optical properties is obtained for these materials.

Postmodifying prepositional phrases in English and Spanish (with special reference to locative postmodifiers)

Prepositional phrases are the commonest kind of postmodification in all registers of English (Biber et al. 1999: 634). The locative ones that can be expanded into a defining relative clause (the books [which are] on the table) are usually expressed by such a construction in Spanish (los libros que están encima de la mesa) or by a phrase introduced by de (los libros de encima de la mesa). Wonder (1979) argues that Spanish allows locative phrases with prepositions other than de in the case of"situaciones"activas"" (el aterrizaje en pleno campo) as against"situaciones estáticas" (*el sofá en la sala), and if the phrase can be given an adverbial rather than, or in addition to, an adjectival interpretation (el ruido en la calle), especially if that phrase implies an alternative location for an object or contrast with another similar object (el sofá en la sala contigua). This paper further investigates this claim and looks at Spanish equivalents of English postmodifying prepositional phrases in general, while proposing an explanation for the choice of these different structures in Spanish based on considerations of lexical density. Resumen: Las frases preposicionales constituyen el tipo más frecuente de posmodificación en todos los registros del inglés (Biber et a. 1999: 634). En el español, las expresiones locativas suelen incorporar un pronombre relativo y un verbo (the books [which are] on the table > los libros que están encima de la mesa), o bien expresarse mediante una frase introducida por la preposición de (los libros de encima de la mesa). Wonder (1979) sostiene que el español permite el uso de preposiciones que no sean de en las frases locativas en el caso de"situaciones"activas"" (el aterrizaje en pleno campo) frente a"situaciones estáticas" (*el sofá en la sala), y también si la frase puede tener una función adverbial antes que, o además de, una interpretación adjetiva (el ruido en la calle), sobre todo si dicha frase encierra la idea de una posición alternativa para un objeto, o bien un contraste con otro objeto similar (el sofá en la sala contigua). El presente estudio pretende examinar este argumento y, además, explorar la posmodificación preposicional en español de un modo más general, a la par que propone una explicación sobre la elección de estructura en español que se basa en el criterio de la densidad léxica.