Digital compensation of the side-band-rejection ratio in a fully analog 2SB sub-millimeter receiver

In observational radio astronomy, sideband-separating receivers are preferred, particularly under high atmospheric noise, which is usually the case in the sub-millimeter range. However, obtaining a good rejection ratio between the two sidebands is difficult since, unavoidably, imbalances in the different analog components appear. We describe a method to correct these imbalances without making any change in the analog part of the sideband-separating receiver, specifically, keeping the intermediate-frequency hybrid in place. This opens the possibility of implementing the method in any existing receiver. We have built hardware to demonstrate the validity of the method and tested it on a fully analog receiver operating between 600 and 720GHz. We have tested the stability of calibration and performance vs time and after full resets of the receiver. We have performed an error analysis to compare the digital compensation in two configurations of analog receivers, with and without intermediate frequency (IF) hybrid. An average compensated sideband rejection ratio of 46dB is obtained. Degradation of the compensated sideband rejection ratio on time and after several resets of the receiver is minimal. A receiver with an IF hybrid is more robust to systematic errors. Moreover, we have shown that the intrinsic random errors in calibration have the same impact for configuration without IF hybrid and for a configuration with IF hybrid with analog rejection ratio better than 10dB. Compensated rejection ratios above 40dB are obtained even in the presence of high analog rejection. The method is robust allowing its use under normal operational conditions at any telescope. We also demonstrate that a full analog receiver is more robust against systematic errors. Finally, the error bars associated to the compensated rejection ratio are almost independent of whether IF hybrid is present or not

Ultra-pure digital sideband separation at sub-millimeter wavelengths

Deep spectral-line surveys in the mm and sub-mm range can detect thousands of lines per band uncovering the rich chemistry of molecular clouds, star forming regions and circumstellar envelopes, among others objects. The ability to study the faintest features of spectroscopic observation is, nevertheless, limited by a number of factors. The most important are the source complexity (line density), limited spectral resolution and insufficient sideband (image) rejection (SRR). Dual Sideband (2SB) millimeter receivers separate upper and lower sideband rejecting the unwanted image by about 15 dB, but they are difficult to build and, until now, only feasible up to about 500 GHz (equivalent to ALMA Band 8). For example ALMA Bands 9 (602-720 GHz) and 10 (787-950 GHz) are currently DSB receivers. Aims: This article reports the implementation of an ALMA Band 9 2SB prototype receiver that makes use of a new technique called calibrated digital sideband separation. The new method promises to ease the manufacturing of 2SB receivers, dramatically increase sideband rejection and allow 2SB instruments at the high frequencies currently covered only by Double Sideband (DSB) or bolometric detectors. Methods: We made use of a Field Programmable Gate Array (FPGA) and fast Analog to Digital Converters (ADCs) to measure and calibrate the receiver's front end phase and amplitude imbalances to achieve sideband separation beyond the possibilities of purely analog receivers. The technique could in principle allow the operation of 2SB receivers even when only imbalanced front ends can be built, particularly at very high frequencies. Results: This digital 2SB receiver shows an average sideband rejection of 45.9 dB while small portions of the band drop below 40 dB. The performance is 27 dB (a factor of 500) better than the average performance of the proof-of-concept Band 9 purely-analog 2SB prototype receiver.Comment: 5 page

Contemplative positive psychology: Introducing mindfulness into positive psychology

A pesar de que mindfulness está integrado en muchos manuales de psicología positiva como una técnica “positiva”, apenas se han desarrollado las implicaciones que tiene su uso ni se ha investigado la relación entre mindfulness y bienestar humano. Analizar las principales potencialidades de los dos ámbitos, las posibilidades de integración, así como las posibles contradicciones entre sus mensajes, es fundamental de cara a establecer puentes. Mindfulness es más que una técnica de meditación, lleva implícitos una serie de valores y condicionantes éticos que se adecuan en buena medida con los presupuestos que se proponen desde la psicología positiva, como el desarrollo de la amabilidad, la compasión, y las emociones positivas. El objetivo de este artículo es presentar por un lado aspectos comunes y similitudes, y por otro lado diferencias entre mindfulness y la psicología positiva. También se presentarán los principales estudios que han investigado el papel que tiene mindfulness y las prácticas contemplativas sobre el bienestar humano. Finalmente se discutirá y plantearán futuras líneas de investigación e intervención para acercar ambas propuestas. Although mindfulness is included in many positive psychology manuals as a “positive” technique, the implications of its use have scarcely been developed and the relationship between mindfulness and human well-being has barely been researched. Analyzing the main strengths of the two fields, the possibilities for their integration and the potential contradictions between their messages is essential in order to establish connections. Mindfulness is more than a meditation technique. It has implicit within it a set of values and ethical conditions that coincide to a great extent with the proposed assumptions from positive psychology, such as the development of kindness, compassion, and positive emotions. The aim of this paper is to present, on the one hand, the commonalities and similarities, and on the other, the differences between mindfulness and positive psychology. We also present the main studies that have investigated the role of mindfulness and contemplative practices on human well-being. Finally future research will be discussed and intervention suggested in order to bring the two proposals together

El feedback como medio para fortalecer el desarrollo de competencias a través de los blogs

El artículo aporta información relevante acerca del estudio realizado en la asignatura "Formación y Evaluación Docente y de Aprendizajes" del máster de Investigación en Didáctica, Formación y Evaluación Educativa de la Universidad de Barcelona, orientado a descubrir en qué medida el feedback llevado a cabo por los tutores/as en un entorno 2.0 y con la elaboración de blogs, puede contribuir al desarrollo de competencias personales y profesionales de los estudiantes, a través de una aproximación reflexiva de temas afines con la asignatura, siguiendo un proceso de autorregulación de aprendizajes y con un marcado acento en la evaluación formativa

Hypoglycemic effect of Berberis microphylla G Forst root extract

Purpose: To evaluate the effect of the root extract of Berberis microphylla on glucose uptake and AMPK-activated protein kinase (AMPK) activity in non-resistant and insulin-resistant HepG2 cells.Methods: B. microphylla root was extracted with absolute ethanol, filtered, concentrated and lyophilized. Subsequently, liver cells, HepG2 (resistant and non-insulin resistant), were exposed for 24 h to different concentrations of the extract (10, 5, 2.5 and 1.25 x 10-3 μg/μL) to determine the stimulation of glucose uptake and phosphorylation of AMPK.Results: In HepG2 cells without resistance exposed to B. microphylla root extract, glucose uptake varied from 34 to 59 % of the available glucose while AMPK phosphorylation was 1.9 to 3.6 times the phosphorylation of the control. In insulin-resistant HepG2 cells, glucose uptake varied from 68 to 95 % of available glucose while AMPK phosphorylation was 1.8 to 3.3 times the phosphorylation of the control.Conclusion: The root extract of B. microphylla possesses hypoglycemic effects and stimulates glucose uptake in HepG2 cells with and without resistance by activating AMPK protein.Keywords: Calafate, Diabetes, Antihyperglycemic effect, Phytomedicine, Berberis, Insulin resistanc

Using an Overall Mass-Transfer Coefficient for Prediction of Drying of Chilean Coigüe

A phenomenological model was used to quantify the drying process of Chilean coigüe (Nothofagus dombeyi). This model is based on an overall mass-transfer coefficient, K, which was determined in four laboratory drying runs. The model suitably described the drying of Chilean coigüe lumber of 19- and 30-mm thickness with K ranging from 0.012 to 0.021 ms-1 at a dry-bulb of 60°C and a wet-bulb of 40°C. A preliminary industrial run under somewhat similar conditions in a 100-m3 industrial kiln with 38-mm-thick lumber showing that the drying process could be represented by a K of 0.008 ms-1. The laboratory-scale values of K can be regarded as ideal from which to compare the performance of the industrial unit

PHYTOCHEMICAL CONSTITUENTS OF THE ROOT OF BERBERIS MICROPHYLLA

Objective: To objective of this work was to perform phytochemical qualitative and quantitative analyzes of the main secondary metabolites in the root of Berberis microphylla.Methods: The extracts of B. microphylla root were tested through phytochemical screening and the quantification of the most important constituents was carried out using spectrophotometric and gravimetric techniques.Results: Phytochemical screening of both extracts showed the presence of alkaloids, flavonoids, glycosides, cardiac glycosides, saponins, terpenes,and tannins, which are pharmacologically important. Quantification of the major phytochemicals groups showed that the ethanolic extract contains 3.9% alkaloids, 0.46% flavonoids, 9.53% tannins, and 3.60% saponins. Similarly, the methanolic extract contains 6.61% alkaloids, 0.41% flavonoids, 7.40% tannins, and 1.43% saponins.Conclusion: This is the first time that the presence of tannins, flavonoids, and saponins in this plant has been reported. The medicinal properties of the root of B. microphylla may exist due to the presence secondary metabolites

A database and digital signal processing framework for the perceptual analysis of voice quality

Bermúdez de Alvear RM, Corral J, Tardón LJ, Barbancho AM, Fernández Contreras E, Rando Márquez S, Martínez-Arquero AG, Barbancho I. A database and digital signal processing framework for the perceptual analysis of voice quality. Pan European Voice Conferenc: PEVOC 11 Abstract Book. Aug. 31-Sept.2, 2015.Introduction. Clinical assessment of dysphonia relies on perceptual as much as instrumental methods of analysis [1]. The perceptual auditory analysis is potentially subject to several internal and external sources of bias [2]. Furthermore acoustic analyses which have been used to objectively characterize pathological voices are likely to be affected by confusion variables such as the signal processing or the hardware and software specifications [3]. For these reasons the poor correlation between perceptual ratings and acoustic measures remains to be a controversial matter [4]. The availability of annotated databases of voice samples is therefore of main importance for clinical and research purposes. Databases to perform digital processing of the vocal signal are usually built from English speaking subjects’ sustained vowels [5]. However phonemes vary from one language to another and to the best of our knowledge there are no annotated databases with Spanish sustained vowels from healthy or dysphonic voices. This work shows our first steps to fill in this gap. For the aim of aiding clinicians and researchers in the perceptual assessment of voice quality a two-fold objective was attained. On the one hand a database of healthy and disordered Spanish voices was developed; on the other an automatic analysis scheme was accomplished on the basis of signal processing algorithms and supervised learning machine techniques. Material and methods. A preliminary annotated database was created with 119 recordings of the sustained Spanish /a/; they were perceptually labeled by three experienced experts in vocal quality analysis. It is freely available under Links in the ATIC website (www.atic.uma.es). Voice signals were recorded using a headset condenser cardioid microphone (AKG C-544 L) positioned at 5 cm from the speaker’s mouth commissure. Speakers were instructed to sustain the Spanish vowel /a/ for 4 seconds. The microphone was connected to a digital recorder Edirol R-09HR. Voice signals were digitized at 16 bits with 44100 Hz sampling rate. Afterwards the initial and last 0.5 second segments were cut and the 3 sec. mid portion was selected for acoustic analysis. Sennheiser HD219 headphones were used by judges to perceptually evaluate voice samples. To label these recordings raters used the Grade-Roughness-Breathiness (GRB) perceptual scale which is a modified version of the original Hirano’s GRBAS scale, posteriorly modified by Dejonckere et al., [6]. In order to improve intra- and inter-raters’ agreement two types of modifications were introduced in the rating procedure, i.e. the 0-3 points scale resolution was increased by adding subintervals to the standard 0-3 intervals, and judges were provided with a written protocol with explicit definitions about the subintervals boundaries. By this way judges could compensate for the potential instability that might occur in their internal representations due to the perceptual context influence [7]. Raters’ perceptual evaluations were simultaneously performed by means of connecting the Sennheiser HD219 headphones to a multi-channel headphone preamp Behringer HA4700 Powerplay Pro-XL. The Yin algorithm [8] was selected as initial front-end to identify voiced frames and extract their fundamental frequency. For the digital processing of voice signals some conventional acoustic parameters [6] were selected. To complete the analysis the Mel-Frequency Cepstral Coefficients (MFCC) were further calculated because they are based on the auditory model and they are thus closer to the auditory system response than conventional features. Results. In the perceptual evaluation excellent intra-raters agreement and very good inter-raters agreement were achieved. During the supervised machine learning stage some conventional features were found to attain unexpected low performance in the classification scheme selected. Mel Frequency Cepstral Coefficients were promising for assorting samples with normal or quasi-normal voice quality. Discussion and conclusions. Despite it is still small and unbalanced the present annotated data base of voice samples can provide a basis for the development of other databases and automatic classification tools. Other authors [9, 10, 11] also found that modeling the auditory non-linear response during signal processing can help develop objective measures that better correspond with perceptual data. However highly disordered voices classification remains to be a challenge for this set of features since they cannot be correctly assorted by either conventional variables or the auditory model based measures. Current results warrant further research in order to find out the usability of other types of voice samples and features for the automatic classification schemes. Different digital processing steps could be used to improve the classifiers performance. Additionally other types of classifiers could be taken into account in future studies. Acknowledgment. This work was funded by the Spanish Ministerio de Economía y Competitividad, Project No. TIN2013-47276-C6-2-R has been done in the Campus de Excelencia Internacional Andalucía Tech, Universidad de Málaga. References [1] Carding PN, Wilson JA, MacKenzie K, Deary IJ. Measuring voice outcomes: state of the science review. The Journal of Laryngology and Otology 2009;123,8:823-829. [2] Oates J. Auditory-perceptual evaluation of disordered voice quality: pros, cons and future directions. Folia Phoniatrica et Logopaedica 2009;61,1:49-56. [3] Maryn et al. Meta-analysis on acoustic voice quality measures. J Acoust Soc Am 2009; 126, 5: 2619-2634. [4] Vaz Freitas et al. Correlation Between Acoustic and Audio-Perceptual Measures. J Voice 2015;29,3:390.e1 [5] “Multi-Dimensional Voice Program (MDVP) Model 5105. Software Instruction Manual”, Kay PENTAX, A Division of PENTAX Medical Company, 2 Bridgewater Lane, Lincoln Park, NJ 07035-1488 USA, November 2007. [6] Dejonckere PH, Bradley P, Clemente P, Cornut G, Crevier-Buchman L, Friedrich G, Van De Heyning P, Remacle M, Woisard V. A basic protocol for functional assessment of voice pathology, especially for investigating the efficacy of (phonosurgical) treatments and evaluating new assessment techniques. Guideline elaborated by the Comm. on Phoniatrics of the European Laryngological Society (ELS). Eur Arch Otorhinolaryngol 2001;258:77–82. [7] Kreiman et al. Voice Quality Perception. J Speech Hear Res 1993;36:21-4 [8] De Cheveigné A, Kawahara H. YIN, a fundamental frequency estimator for speech and music. J. Acoust. Soc. Amer. 202; 111,4:1917. [9] Shrivastav et al. Measuring breathiness. J Acoust Soc Am 2003;114,4:2217-2224. [10] Saenz-Lechon et al. Automatic Assessment of voice quality according to the GRBAS scale. Eng Med Biol Soc Ann 2006;1:2478-2481. [11] Fredouille et al. Back-and-forth methodology for objective voice quality assessment: from/to expert knowledge to/from automatic classification of dysphonia. EURASIP J Appl Si Pr 2009.Campus de Excelencia Internacional Andalucía Tech, Universidad de Málaga. Ministerio de Economía y Competitividad, Projecto No. TIN2013-47276-C6-2-R

Evaluacion economica del paso Internacional Pehuenche

141 p.La presente memoria ha considerado relevante calcular los costos de transporte caminero para las dos variantes que actualmente posee el Paso Pehuenche ( Los Cóndores y El Campanario ), esta importante información ayudara a decidir acerca de la conveniencia de optar por una u otra alternativa. Dentro de los principales costos a determinar están los costos de transporte y costos de tiempo para las personas, estos costos se determinaran para las dos variantes: Los Cóndores y El Campanario. En el calculo se asume que la calidad de las variantes no influirá en la decisión de utilizar el Paso Pehuenche, además el transito actual y proyectado será el mismo para ambas alternativas; es decir, supondremos que cualquier vehículo que llegue al Paso Pehuenche cruzara la cordillera utilizando la ruta de la Cuesta Los Cóndores o de la Variante Campanario ( se ha considerado este supuesto incluso aunque existan casi 7 Km. de diferencia, ya que así se podrá realizar una comparación de los costos en que las diferencias se produzcan no solo por distancias, sino también por las características técnicas de los caminos). De esta manera se podrá determinar cual variante posee menores costos de transporte (costos de operación y tiempo de viaje) para una demanda de transito igual. Para determinar los costos de ambas vías se utilizara el modelo HDM3, que actualmente usa el Ministerio de Obras Publicas en la Evaluación Social de Proyectos Camineros. La presente memoria pretende contribuir en las decisiones económicas de este proyecto, decisiones que afectaran la competitividad de empresas Chilenas que exportan hacia países del conosur; también se debe mencionar que Chile generaría una Buena imagen como Pals al tener un paso internacional complementario al paso Los Libertadores Conclusiones y Recomendaciones: En base a los resultados que arrojo este estudio se pudo concluir que en el corto y el mediano plazo la construcción del paso El Pehuenche, se debería realizar por la Cuesta Los Cóndores la cual posee para 20 anos un VAN (12%) de $-18.654.473.447 , en cambio el VAN (12$ - 20.494.310.302. La mejor o la menos mala de las alternativas es la Cuesta Los Cóndores; en cambio si consideramos un horizonte de tiempo mas lejano esta decisión podría cambiar porque la alternativa Variante Campanario posee ahorros de costos crecientes, lo que podría cubrir la mayor inversión que implica la construcción de la alternativa Variante Campanario. Considerando el valor actual neto de ambas alternativas, se recomienda la creación de un peaje, el cual generaría ingresos y permitiría que el proyecto a un mediano y largo plazo sea rentable. Se determine un peaje de equilibrio, es decir un valor de peaje por tipo de automóvil que cubriera los montos de Inversión y los costos operacionales de cada alternativa. Se calculo que el peaje de equilibrio para 30 años, de la Cuesta Los Cóndores seria de $10.866 para automóviles y$21.733 para buses y camiones ( Considerando como ano 1 el ano 2003 ), en cambio para la Variante Campanario el valor de peaje seria de $11.677 y$23.353 respectivamente. El mayor valor de peaje para la Variante Campanario se explica principalmente por el mayor monto de inversión que posee esta alternativa en relación a la Cuesta Los Cóndores. De acuerdo a los resultados mencionados se concluyo que para el proyecto de 30 anos el peaje de la Variante Campanario es un 7,45% mayor que de la Cuesta Los Cóndores, sin embargo, si el proyecto tuviera una duración de 40 anos, la variación entre los valores de peaje de ambas alternativas seria de 6,3%, es decir, a medida que el proyecto aumenta su duración , la variación mencionada bajara aún mas; por lo tanto a un largo plazo la Variante Campanario disminuirá su desventaja en relación a la Cuesta Los Cóndores respecto del valor de peaje