Aplicaciones de las ondas electromagnéticas en productos alimenticios

High frequency waves have a great potential in Food technology, both at house-cooking or industrial use. At home, microwave oven is a widely used equipment at kitchens of developed world. By contrast, in the Food Industry, the use of microwave and radio-frequency techniques is relatively small as a consequence of the need of equipment and specialised staff. The low application of such technology is related to the poor knowledge of the heating process through high frequencies as well as their critical factors that determine the quality of the heating process (dielectric constants, product geometry, distribution in the packaging, etc.). This article intends to clarify the basis of this technology besides describing some applications.Las altas frecuencias tienen un gran potencial dentro de la tecnología de alimentos, tanto en el ámbito doméstico como en el industrial. En el ámbito doméstico, el horno microondas es un equipo conocido que hoy en día se ha convertido en un elemento importante en las cocinas del mundo desarrollado. En el caso de la industria alimentaria, el uso de las microondas y radiofrecuencias es todavía escaso debido a la necesidad de equipos y personal especializado. La falta de aplicación de esta tecnología viene relacionada con la falta de conocimiento de lo que es un calentamiento por altas frecuencias y el desconocimiento de los factores críticos que determinarán la calidad de este calentamiento (constantes dieléctricas, geometría del producto, distribución en el envase, etc.). Con este artículo se busca aclarar las bases de esta tecnología, además de describir algunas aplicaciones

Hyperspectral imaging to characterize table grapes

Table grape quality is of importance for consumers and thus for producers. Its objective quality is usually determined by destructive methods mainly based on sugar content. This study proposed to evaluate the possibility of hyperspectral imaging to characterize table grapes quality through its sugar (TSS), total flavonoid (TF), and total anthocyanin (TA) contents. Different data pretreatments (WD, SNV, and 1st and 2nd derivative) and different methods were tested to get the best prediction models: PLS with full spectra and then Multiple Linear Regression (MLR) were realized after selecting the optimal wavelengths thanks to the regression coefficients (coefficients) and the Variable Importance in Projection (VIP) scores. All models were good at showing that hyperspectral imaging is a relevant method to predict sugar, total flavonoid, and total anthocyanin contents. The best predictions were obtained from optimal wavelength selection based on coefficients for TSS and from VIPs optimal wavelength windows using SNV pre-treatment for total flavonoid and total anthocyanin content. Thus, good prediction models were proposed in order to characterize grapes while reducing the data sets and limit the data storage to enable an industrial use

HSC-CLAUDS survey: The star formation rate functions since z ~ 2 and comparison with hydrodynamical simulations

Star formation rate functions (SFRFs) give an instantaneous view of the distribution of star formation rates (SFRs) in galaxies at different epochs. They are a complementary and more stringent test for models than the galaxy stellar mass function, which gives an integrated view of the past star formation activity. However, the exploration of SFRFs has been limited thus far due to difficulties in assessing the SFR from observed quantities and probing the SFRF over a wide range of SFRs. We overcome these limitations thanks to an original method that predicts the infrared luminosity from the rest-frame UV/optical color of a galaxy and then its SFR over a wide range of stellar masses and redshifts. We applied this technique to the deep imaging survey HSC-CLAUDS combined with near-infrared and UV photometry. We provide the first SFR functions with reliable measurements in the high- and low-SFR regimes up to $z=2$ and compare our results with previous observations and four state-of-the-art hydrodynamical simulations.Comment: 29 pages, 19 figure

Aplicaciones de las ondas electromagnéticas en productos alimenticios

Las altas frecuencias tienen un gran potencial dentro de la tecnología de alimentos, tanto en el ámbito doméstico como en el industrial. En el ámbito doméstico, el horno microondas es un equipo conocido que hoy en día se ha convertido en un elemento importante en las cocinas del mundo desarrollado. En el caso de la industria alimentaria, el uso de las microondas y radiofrecuencias es todavía escaso debido a la necesidad de equipos y personal especializado. La falta de aplicación de esta tecnología viene relacionada con la falta de conocimiento de lo que es un calentamiento por altas frecuencias y el desconocimiento de los factores críticos que determinarán la calidad de este calentamiento (constantes dieléctricas, geometría del producto, distribución en el envase, etc.). Con este artículo se busca aclarar las bases de esta tecnología, además de describir algunas aplicaciones.High frequency waves have a great potential in Food technology, both at house-cooking or industrial use. At home, microwave oven is a widely used equipment at kitchens of developed world. By contrast, in the Food Industry, the use of microwave and radio-frequency techniques is relatively small as a consequence of the need of equipment and specialised staff. The low application of such technology is related to the poor knowledge of the heating process through high frequencies as well as their critical factors that determine the quality of the heating process (dielectric constants, product geometry, distribution in the packaging, etc.). This article intends to clarify the basis of this technology besides describing some applications

Emission from the circumgalactic medium: from cosmological zoom-in simulations to multiwavelength observables

We simulate the flux emitted from galaxy haloes in order to quantify the brightness of the circumgalactic medium (CGM). We use dedicated zoom-in cosmological simulations with the hydrodynamical adaptive mesh refinement code ramses, which are evolved down to z = 0 and reach a maximum spatial resolution of 380 h−1 pc and a gas mass resolution up to 1.8×105h−1M⊙ in the densest regions. We compute the expected emission from the gas in the CGM using cloudy emissivity models for different lines (e.g. Lyα, C iv, O vi, C vi, O viii) considering UV background fluorescence, gravitational cooling and continuum emission. In the case of Lyα, we additionally consider the scattering of continuum photons. We compare our predictions to current observations and find them to be in good agreement at any redshift after adjusting the Lyα escape fraction. We combine our mock observations with instrument models for Faint Intergalactic Redshifted Emission Balloon-2 (FIREBall-2; UV balloon spectrograph) and HARMONI (visible and NIR IFU on the ELT) to predict CGM observations with either instrument and optimize target selections and observing strategies. Our results show that Lyα emission from the CGM at a redshift of 0.7 will be observable with FIREBall-2 for bright galaxies (NUV∼18 mag), while metal lines like O vi and C iv will remain challenging to detect. HARMONI is found to be well suited to study the CGM at different redshifts with various tracers

Emission from the circumgalactic medium: from cosmological zoom-in simulations to multiwavelength observables

We simulate the flux emitted from galaxy haloes in order to quantify the brightness of the circumgalactic medium (CGM). We use dedicated zoom-in cosmological simulations with the hydrodynamical adaptive mesh refinement code RAMSES, which are evolved down to z = 0 and reach a maximum spatial resolution of 380 h−1 pc and a gas mass resolution up to 1.8×105 h−1 M⊙ in the densest regions. We compute the expected emission from the gas in the CGM using CLOUDY emissivity models for different lines (e.g. Lyα, C IV, O VI, C VI, O VIII) considering UV background fluorescence, gravitational cooling and continuum emission. In the case of Lyα, we additionally consider the scattering of continuum photons. We compare our predictions to current observations and find them to be in good agreement at any redshift after adjusting the Lyα escape fraction. We combine our mock observations with instrument models for Faint Intergalactic Redshifted Emission Balloon-2 (FIREBall-2; UV balloon spectrograph) and HARMONI (visible and NIR IFU on the ELT) to predict CGM observations with either instrument and optimize target selections and observing strategies. Our results show that Lyα emission from the CGM at a redshift of 0.7 will be observable with FIREBall-2 for bright galaxies (NUV∼18 mag), while metal lines like O VI and C IV will remain challenging to detect. HARMONI is found to be well suited to study the CGM at different redshifts with various tracers.</p

Combining the CLAUDS and HSC-SSP surveys. U +grizy(+YJHKs) photometry and photometric redshifts for 18M galaxies in the 20 deg2 of the HSC-SSP Deep and ultraDeep fields

International audienceWe present the combination of the Canada-France-Hawaii Telescope (CHFT) Large Area U-bands Deep Survey (CLAUDS) and the Hyper-Suprime-Cam (HSC) Subaru Strategic Program (HSC-SSP) data over their four deep fields. We provide photometric catalogs for u, u* (CFHT-MegaCam), g, r, i, z, and y (Subaru-HSC) bands over ~20 deg2, complemented in two fields by data from the Visible and Infrared Survey Telescope for Astronomy (VISTA) Deep Extragalactic Observations (VIDEO) survey and the UltraVISTA survey, thus extending the wavelength coverage toward near-infrared with VIRCAM Y, J, H, and Ks observations over 5.5 deg2. The extraction of the photometry was performed with two different softwares: the HSC pipeline hscPipe and the standard and robust SExtractor software. Photometric redshifts were computed with template-fitting methods using the new Phosphoros code for the hscPipe photometry and the well-known Le Phare code for the SExtractor photometry. The products of these methods were compared with each other in detail. We assessed their quality using the large spectroscopic sample available in those regions, together with photometry and photometric redshifts from COSMOS2020, the latest version of the Cosmic Evolution Survey catalogs. We find that both photometric data sets are in good agreement in Ugrizy down to magnitude ~26, and to magnitude ~24.5 in the YJHKs bands. We achieve good performance for the photometric redshifts, reaching precisions of σNMAD ≲ 0.04 down to mi ~ 25, even using only the CLAUDS and HSC bands. At the same magnitude limit, we measured an outlier fraction of η ≲ 10% when using the Ugrizy bands, and down to η ≲ 6% when considering near-infrared data. The hscPipe plus Phosphoros pipeline performs slightly worse in terms of photometric-redshifts precision and outlier fraction than its SExtractor plus Le Phare counterpart, which has essentially been tracked down to differences in the photometry. Thus, this work is also a validation of the Phosphoros code. The photometric catalogs with the data and photometric redshifts from the two pipelines are presented and made publicly available. The catalogs are also available at the CDS via anonymous ftp to cdsarc.cds.unistra.fr (ftp://130.79.128.5) or via https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/670/A82</A