Simplified Metrics Calculation for Soft Bit Detection in DVB-T2

The constellation rotation and cyclic quadrature component delay (RQD) technique has been adopted in the second generation terrestrial digital video broadcasting (DVB-T2) standard. It improves the system performance under severe propagation conditions, but introduces serious complexity problems in the hardware implementation of the detection process. In this paper, we present a simplified scheme that greatly reduces the complexity of the demapper by simplifying the soft bit metrics computation having a negligible overall system performance loss

Experimental Test of a Two-dimensional Approximation for Dielectric Microcavities

Open dielectric resonators of different shapes are widely used for the manufacture of microlasers. A precise determination of their resonance frequencies and widths is crucial for their design. Most microlasers have a flat cylindrical geometry, and a two-dimensional approximation, the so-called method of the effective index of refraction, is commonly employed for numerical calculations. Our aim has been an experimental test of the precision and applicability of a model based on this approximation. We performed very thorough and accurate measurements of the resonance frequencies and widths of two passive circular dielectric microwave resonators and found significant deviations from the model predictions. From this we conclude that the model generally fails in the quantitative description of three-dimensional dielectric resonators.Comment: 10 pages, 13 figure

Aroma composition of commercial truffle flavoured oils: does it really smell like truffle?

The present study analyzes the aromatic and odour volatile profiles of truffle flavoured oils commercialized as “black truffle oil”. The aim of this work is twofold: to define the sensory space associated to these products and to explore the possible fraudulent use of artificial flavouring agents not properly identified on the label. For this purpose, 12 commercial truffle flavoured oils available in the Spanish market were submitted to descriptive sensory analysis by a trained panel. The three oils presenting the most interesting profile (in terms of odour nature and/or complexity) were also analyzed by olfactometric analysis, in order to identify the chemical compounds responsible on their aroma. The correlation of sensory and olfactometric data made it possible to understand some of the sensory differences observed among samples, as well as to identify irregularities with respect to the ingredients labelling of some of the studied samples

Changes in the Physicochemical and Nutritional Parameters of Picual and Arbequina Olive Oils during Frying

Deep fat frying is an important cooking process in Mediterranean countries. Olive oil is a very convenient fat to use for this culinary purpose. The chemical composition of olive oils differs from edible oils in terms of fatty acid and antioxidant compounds that gives olive oil its greater stability. The aim of this work was to describe the stability of Picual and Arbequina olive oil during deep frying of frozen potatoes in comparison with high oleic sunflower oil. Changes in different physicochemical and nutritional parameters were studied during frying. Picual olive oil had a higher stability in comparison with high oleic sunflower oil and Arbequina olive oil. Picual olive oil is very suitable for frying because it is able to undergo the greatest number of frying cycles without exceeding the limits allowed by regulations. This behavior is due to its phenolic content, the lower loss in tocopherol and better stability. Practical Applications: The information gained from this research could be very appropriate for consumers and for the industry to know which variety of olive oil is more suitable for frying longer frying cycles without exceeding the limits allowed by regulation and remain in good quality

Technical Note:First report on an in vivo range probing quality control procedure for scanned proton beam therapy in head and neck cancer patients

PURPOSE: The capability of proton therapy to provide highly conformal dose distributions is impaired by range uncertainties. The aim of this work is to apply range probing (RP), a form of a proton radiography-based quality control (QC) procedure for range accuracy assessment in head and neck cancer (HNC) patients in a clinical setting. METHODS AND MATERIALS: This study included seven HNC patients. RP acquisition was performed using a multi-layer ionization chamber (MLIC). Per patient, two RP frames were acquired within the first two weeks of treatment, on days when a repeated CT scan was obtained. Per RP frame, integral depth dose (IDD) curves of 81 spots around the treatment isocentre were acquired. Range errors are determined as a discrepancy between calculated IDDs in the treatment planning system and measured residual ranges by the MLIC. Range errors are presented relative to the water equivalent path length of individual proton spots. In addition to reporting results for complete measurement frames, an analysis, excluding range error contributions due to anatomical changes, is presented. RESULTS: Discrepancies between measured and calculated ranges are smaller when performing RP calculations on the day-specific patient anatomy rather than the planning CT. The patient-specific range evaluation shows an agreement between calculated and measured ranges for spots in anatomically consistent areas within 3% (1.5 standard deviation). CONCLUSIONS: The results of a RP-based QC procedure implemented in the clinical practice for HNC patients have been demonstrated. The agreement of measured and simulated proton ranges confirms the 3% uncertainty margin for robust optimization. Anatomical variations show a predominant effect on range accuracy, motivating efforts towards the implementation of adaptive radiotherapy

Influencia del retraso en el procesado de las aceitunas tras la recolección, en parámetros físico-químicos y nutricionales del aceite de oliva de la variedad Racimilla

The aim of this work was to study how the delay time between harvesting and processing affects the physicochemical and nutritional parameters of Racimilla olive (Olea europaea L.) oil. The physicochemical parameters (titratable acidity, peroxide value, coefficients of specific extinction and pigments content) changed remarkably. The nutritional parameters such as fatty acids profile, total phenols and vitamin E also suffered a change with the delay in processing. Physicochemical and nutritional parameter modifications were detrimental to olive oil quality. In conclusion, a delay in processing after harvesting is not efficient to preserve the physicochemical and nutritional quality of the olive oil from the Racimilla variety.El objetivo de este trabajo fue estudiar cómo afecta el tiempo que transcurre entre la recolección y procesado en los parámetros físico-químicos y nutricionales del aceite de oliva (Olea europaea L.) de la variedad aragonesa Racimilla. Los parámetros físico-químicos (acidez, índice de peróxidos, coeficientes de extinción y contenido en pigmentos) se modificaron visiblemente. Los parámetros nutricionales como el perfil de ácidos grasos, contenido en fenoles totales y vitamina E sufrieron también un cambio al retrasar el procesado. Tanto las modificaciones en los parámetros físico-químicos como en los nutricionales fueron negativas desde el punto de vista de la calidad del aceite. A la vista de los resultados, el retraso en el procesado tras la recolección es ineficiente para preservar la calidad físico-química y nutricional del aceite de oliva de la variedad Racimilla

Aceite de oliva virgen extra del Somontano: evaluación de las modificaciones físico- químicas tras la fritura doméstica de patatas prefritas congeladas

The behavior of Somontano extra virgin olive oil (obtained from Empeltre and Arbequina olive varieties) in the domestic deep frying of prefried frozen potatoes was studied by submitting the olive oil to successive frying cycles. After different frying cycles physico-chemical modifications were monitored through the determination of several chemical (iodine value, total phenols content) and physical parameters (viscosity and ultraviolet spectra). An increase in viscosity and a decrease in iodine value, total phenol content and an increase in absorbance at 235, 269 y 280 nm were observed. In general, Somontano olive oil was revealed appropriate for domestic frying because of the high number of frying cycles permitted before reaching the polar compound limit established by Spanish legislation.Se estudió el comportamiento del aceite de oliva virgen extra del Somontano (obtenido a partir de aceitunas de las variedades Empeltre y Arbequina) en la fritura doméstica de patatas prefritas congeladas por inmersión, sometiendo al aceite a ciclos sucesivos de fritura. Tras los distintos ciclos se monitorizaron las modificaciones físico-químicas mediante la determinación de diversos parámetros químicos (indice de yodo, contenido en fenoles totales) y físicos (viscosidad y espectros ultravioleta). Se observó un aumento de la viscosidad, y una disminución en el índice de yodo, en el contenido de fenoles, así como el aumento de la absorbancia en el ultravioleta a 235, 269 y 280 nm. Sin embargo, el aceite del Somontano se reveló como muy adecuado para la fritura doméstica por el elevado número de ciclos de fritura (66) que se pudieron realizar sin sobrepasar el límite de compuestos polares establecido por la legislación

Range probing as a quality control tool for CBCT-based synthetic CTs:In vivo application for head and neck cancer patients

PURPOSE: Cone‐beam CT (CBCT)‐based synthetic CTs (sCT) produced with a deep convolutional neural network (DCNN) show high image quality, suggesting their potential usability in adaptive proton therapy workflows. However, the nature of such workflows involving DCNNs prevents the user from having direct control over their output. Therefore, quality control (QC) tools that monitor the sCTs and detect failures or outliers in the generated images are needed. This work evaluates the potential of using a range‐probing (RP)‐based QC tool to verify sCTs generated by a DCNN. Such a RP QC tool experimentally assesses the CT number accuracy in sCTs. METHODS: A RP QC dataset consisting of repeat CTs (rCT), CBCTs, and RP acquisitions of seven head and neck cancer patients was retrospectively assessed. CBCT‐based sCTs were generated using a DCNN. The CT number accuracy in the sCTs was evaluated by computing relative range errors between measured RP fields and RP field simulations based on rCT and sCT images. RESULTS: Mean relative range errors showed agreement between measured and simulated RP fields, ranging from −1.2% to 1.5% in rCTs, and from −0.7% to 2.7% in sCTs. CONCLUSIONS: The agreement between measured and simulated RP fields suggests the suitability of sCTs for proton dose calculations. This outcome brings sCTs generated by DCNNs closer toward clinical implementation within adaptive proton therapy treatment workflows. The proposed RP QC tool allows for CT number accuracy assessment in sCTs and can provide means of in vivo range verification

Optimizing calibration settings for accurate water equivalent path length assessment using flat panel proton radiography

Proton range uncertainties can compromise the effectiveness of proton therapy treatments. Water equivalent path length (WEPL) assessment by flat panel detector proton radiography (FP-PR) can provide means of range uncertainty detection. Since WEPL accuracy intrinsically relies on the FP-PR calibration parameters, the purpose of this study is to establish an optimal calibration procedure that ensures high accuracy of WEPL measurements. To that end, several calibration settings were investigated. FP-PR calibration datasets were obtained simulating PR fields with different proton energies, directed towards water-equivalent material slabs of increasing thickness. The parameters investigated were the spacing between energy layers (ΔE) and the increment in thickness of the water-equivalent material slabs (ΔX) used for calibration. 30 calibrations were simulated, as a result of combining ΔE=9, 7, 5, 3, 1 MeV and ΔX=10, 8, 5, 3, 2, 1 mm. FP-PRs through a CIRS electron density phantom were simulated, and WEPL images corresponding to each calibration were obtained. Ground truth WEPL values were provided by range probing multi-layer ionization chamber simulations on each insert of the phantom. Relative WEPL errors between FP-PR simulations and ground truth were calculated for each insert. Mean relative WEPL errors and standard deviations across all inserts were computed for WEPL images obtained with each calibration. Large mean and standard deviations were found in WEPL images obtained with large ΔE values (ΔE= 9 or 7MeV), for any ΔX. WEPL images obtained with ΔE≤ 5MeV and ΔX≤ 5mm resulted in a WEPL accuracy with mean values within ±0.5% and standard deviations around 1%. An optimal FP calibration in the framework of this study was established, characterized by 3MeV≤ ΔE ≤ 5MeV and 2mm ≤ ΔX ≤ 5mm. Within these boundaries, highly accurate WEPL acquisitions using FP-PR are feasible and practical, holding the potential to assist future online range verification quality control procedures