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

What is the best method for preserving the genuine black truffle (Tuber melanosporum) aroma? An olfactometric and sensory approach

The aim of this work was to evaluate the effects of different preservation methods (freeze-drying, hot-air drying, freezing and canning) on the aroma profile of T. melanosporum truffles. Volatile organic compounds (VOCs) were extracted by solid-phase microextraction (SPME) and analysed by gas-chromatography olfactometry to monitor changes occurring in key-aroma compounds. Samples were also submitted to descriptive sensory analysis by a panel of trained judges, with the aim of correlating both sets of data. Freeze-drying - and to a lesser extent hot-air drying - were the only treatments able to retain key-compounds such as dimethylsulphide (DMS) and dimethyldisulphide (DMDS), evoking the aroma typically associated with fresh truffle. Principal component analysis (PCA) performed on the descriptive data showed the sensorial proximity between fresh and freeze-dried truffle, and also the differences between them and those frozen and canned. Despite some differences in the odour volatile profile of fresh and freezed-dried truffles (mainly the lack of 2, 3-butanedione and branched ethyl esters), freeze-drying is the most suitable technique for preserving the overall original aroma of fresh truffle. Several key-odour compounds - mainly unsaturated linear chain carbonyl compounds, sulphur and pyrrole derivates - emerge as biomarkers of the studied technologies

Potential of a new strain of Bacillus amyloliquefaciens BUZ-14 as a biocontrol agent of postharvest fruit diseases

The biocontrol potential of the Bacillus amyloliquefaciens strain BUZ-14 was tested against the main postharvest diseases of orange, apple, grape and stone fruit. After characterizing the temperature and pH growth curves of strain BUZ-14, its in vitro antifungal activity was determined against Botrytis cinerea, Monilinia fructicola, M. laxa, Penicillium digitatum, P. expansum and P. italicum. Subsequently, in vivo activity was tested against these pathogens by treating fruit with cells, endospores and cell-free supernatants. The in vitro results showed that BUZ-14 inhibited the growth of all the pathogens tested corresponding to the least susceptible species, P. italicum, and the most susceptible, M. laxa. In vivo tests corroborated these results as most of the treatments decreased the incidence of brown rot in stone fruit from 100% to 0%, establishing 107 CFU mL-1 as the minimum inhibitory concentration. For the Penicillium species a preventive treatment inhibited P. digitatum and P. italicum growth in oranges and reduced P. expansum incidence in apples from 100% to 20%. Finally, it has been demonstrated that BUZ-14 was able to survive and to control brown rot in peaches stored at cool temperatures, making it a very suitable biocontrol agent for application during the post-harvest storage and marketing of horticultural products

Effect of modified atmosphere packaging (MAP) and UC-C irradiation on postharvest quality of red raspberries

Red raspberries (Rubus idaeus L.) are highly appreciated by consumers. However, their postharvest shelf life scarcely exceeds 5 d under the refrigeration temperatures usually applied during commercialization, due to their high susceptibility to dehydration, softening and rot incidence. Thus, the objective of this study was to investigate the ability of UV-C radiation (UV1: 2 kJ m-2 and UV2: 4 kJ m-2 ), passive modified atmosphere packaging (MAP) with transmission rates (TR) for O2 and CO2 of 1805 mL d-1 and 1570 mL d-1 (MAP1), and 902 mL d-1 and 785 mL d-1 (MAP2), respectively, and the combination of both technologies to prolong raspberries’ shelf life at 6¿ C. Their influence on respiration, physicochemical parameters, and microbiological and nutritional quality was assessed during 12 d of storage. The combination of 4 kJ m-2 UV-C radiation and a packaging film with O2 and CO2 transmission rates of 902 mL d-1 and 785 mL d-1, respectively, produced a synergistic effect against rot development, delaying senescence of the fruit. The UV2MAP2 and MAP2 samples only showed 1.66% rot incidence after 8 d of storage. The UV2MAP2 samples also had higher bioactive content (1.76 g kg-1 of gallic acid equivalents (GAE), 1.08 g kg-1 of catechin equivalents (CE) and 0.32 g kg-1 of cyanidin 3-O-glucoside equivalents (CGE)) than the control samples at the end of their shelf life. Moreover, the mass loss was minimal (0.56%), and fruit color and firmness were maintained during shelf life. However, the rest of the batches were not suitable for commercialization after 4 d due to excessive mold development. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

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

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

Respiration rate determination of black truffles (Tuber melanosporum) and summer truffles (Tuber aestivum) recollected in Aragón

[SPA] Entre los hongos comestibles las trufas son las más apreciadas por sus propiedades organolépticas y las que alcanzan un mayor valor económico. Actualmente los procedimientos de conservación postcosecha que son aplicados a numerosos productos frescos (frutas, vegetales y algunas especies de setas) no se utilizan en trufas frescas, limitando así la vida útil de tan apreciado producto. El envasado en atmósferas modificadas (EAM) podría ser una alternativa muy válida. La determinación de la velocidad de respiración del producto es un paso necesario y previo al diseño del sistema de conservación en atmósferas modificadas. La velocidad de respiración se determinó en función del consumo de O2 y la producción de CO2 en el tiempo y en las especies Tuber aestivum y Tuber melanosporum. Se utilizó un sistema cerrado para valorar la concentración de O2 y de CO2 mediante cromatografía de gases (cromatógrafo Hewlett Packard 4890-A, con detector de conductividad térmica). Los ensayos se realizaron por triplicado y a tres distintas temperaturas: 4°C, 10°C y 23°C. Los resultados demuestran una alta actividad metabólica (45-174 mL kg-1 h-1 O2 para trufa de verano y 48-217 O2 mL kg-1 h-1 para trufa negra) que se incrementa con la temperatura. También establecen una dependencia lineal entre la velocidad de respiración y la concentración de O2 y que la tasa respiratoria a 4°C y 10°C es similar en ambas especies; sin embargo a 23°C es claramente superior en la trufa negra. [ENG] Among the edible fungi, truffles (Tuber spp.) have an important gastronomic value due to their organoleptic properties such as their taste and unique aroma. Currently, conservation procedures applied to other fresh produce (fruits, vegetables and mushrooms) are not applied to fresh truffles thus limiting their shelf life. The use of modified atmospheres packaging (MAP) to extend the shelf life of truffles would be considered as an alternative. Before designing the MAP for a product it is necessary to determine the respiration rate. Therefore, the respiration rate of Tuber aestivum and Tuber melanosporum was determined by O2 depletion and CO2 formation. The O2 and CO2 concentrations were determined using a close-system by gas chromatography (Hewlett Packard 4890-A chromatograph, equipped with a thermal conductivity detector). Essays were performed in triplicates at three different temperatures: 4°C, 10°C and 23°C. The close-system experiments with Tuber aestivum and Tuber melanosporum revealed high respiration rates in both species (45-174 O2 mL kg-1 h-1 for summer truffle and 48-217 O2 mL kg-1 h-1 for black truffle) increasing with temperature. A linear dependence of respiration rate on O2 concentration was also founded. The respiration rate at 4°C and 10°C were similar for both species, nevertheless at 23°C the metabolic activity was higher for black truffles

Selective Reflection Spectroscopy on the UV Third Resonance Line of Cs : Simultaneous Probing of a van der Waals Atom-Surface Interaction Sensitive to Far IR Couplings and of Interatomic Collisions

We report on the analysis of FM selective reflection experiments on the 6S1/2->8P3/2 transition of Cs at 388 nm, and on the measurement of the surface van der Waals interaction exerted by a sapphire interface on Cs(8P3/2). Various improvements in the systematic fitting of the experiments have permitted to supersede the major difficulty of a severe overlap of the hyperfine components, originating on the one hand in a relatively small natural structure, and on the other hand on a large pressure broadening imposed by the high atomic density needed for the observation of selective reflection on a weak transition. The strength of the van der Waals surface interaction is evaluated to be 73$\pm$10 kHz.$\mu$m3. An evaluation of the pressure shift of the transition is also provided as a by-product of the measurement. We finally discuss the significance of an apparent disagreement between the experimental measurement of the surface interaction, and the theoretical value calculated for an electromagnetic vacuum at a null temperature. The possible influence of the thermal excitation of the surface is evoked, because, the dominant contributions to the vW interaction for Cs(8P3/2) lie in the far infrared range.Comment: submitted to Laser Physics - issue in the memory of Herbert Walther