Recursion Polynomials of Unfolded Sequences

Watermarking digital media is one of the important chal- lenges for information hiding. Not only the watermark must be resistant to noise and against attempts of modification, legitimate users should not be aware that it is embedded in the media. One of the techniques for watermarking is using an special variant of spread-spectrum tech- nique, called frequency hopping. It requires ensembles of periodic binary sequences with low off-peak autocorrelation and cross-correlation. Un- fortunately, they are quite rare and difficult to find. The small Kasami, Kamaletdinov, and Extended Rational Cycle constructions are versatile, because they can also be converted into Costas-like arrays for frequency hopping. We study the implementation of such ensembles using linear feedback shift registers. This permits an efficient generation of sequences and arrays in real time in FPGAs. Such an implementation requires minimal memory usage and permits dynamic updating of sequences or arrays. The aim of our work was to broaden current knowledge of sets of se- quences with low correlation studying their implementation using linear feedback shift registers. A remarkable feature of these families is their similarities in terms of implementation and it may open new way to characterize sequences with low correlation, making it easier to gener- ate them. It also validates some conjectures made by Moreno and Tirkel about arrays constructed using the method of composition.Supported by Consejería de Universidades e Investigación, Medio Ambiente y Política Social, Gobierno de Cantabria (ref. VP34

The energy efficiency of the ergodic fading relay channel

In this paper, we address the energy ef ciency analysis of the relay channel under ergodic fading. The study considers full duplex and half duplex terminals. Since the capacity of general relay channels is unknown, we investigate achievable rates with decode and forward and capacity upper bounds with the cut-set bound. The maximum rate per energy and the slope of the spectral ef ciency with the energy per bit are computed to asses the impact of the duplexing capabilities, the resource allocation and the channel fading distribution.Postprint (published version

Upper nound on outage capacity of orthogonal relay networks

We consider the orthogonal multiple relay channel at the low SNR regime.The source transmits to the destination and all the possible relays in one channel and the relays transmit in different and orthogonal channels making use of the transmission received from the source. This cooperative strategy achieves diversity gains at a high cost in bandwidth efficiency, due to the orthogonality of the transmissions. However, it has the desired benefit of allowing all the nodes in the network to behave as in a point to point channel. Based on the max-flow min-cut upper bound for relay networks, we explore the capacity limits of this kind of communication, obtaining an upper bound on the capacity when full channel state information (CSI) is available at every network node. This focus gives insight on the design of the transmitting strategy and define how feedback from relays and destination can be performed practically and optimally, giving ideas for higher layer protocols.Postprint (published version

Hidrocarburos aromáticos policíclicos (HAPs) (I): Medidas de prevención y control

Measures of prevention and control against polycyclic aromatic hydrocarbons (PAHs) focus on an official food control, a code of best practice to reduce PAHs levels by controlling industry and in the development of a chemopreventive strategy. Regulation (EU) 835/2011 establishes maximum levels of PAHs for each food group. In addition, Regulations (EU) 333/2007 and 836/2011 set up the methods of sampling and analysis for its official control. Scientific studies prove that the chemopreventive strategy is effective against these genotoxic compounds effects. Most chemopreventive compounds studied with proven protective effects against PAHs are found in fruit and vegetables.Las medidas de prevención y control que existen frente a los hidrocarburos aromáticos policíclicos (HAPs) consisten en realizar un control oficial, en llevar a cabo un código de buenas prácticas para reducir los niveles de HAPs en las industrias y en el desarrollo de una estrategia quimiopreventiva. El Reglamento (UE) 835/2011 establece los contenidos máximos de HAPs en los productos alimenticios. Además los Reglamentos (UE) 333/2007 y 836/2011 establecen los métodos de muestreo y análisis para el control oficial de estos compuestos. Estudios científicos demuestran que la estrategia quimiopreventiva es eficaz frente a los efectos genotóxicos de estos compuestos. La mayoría de los compuestos quimiopreventivos estudiados con efecto protector frente a los HAPs, se encuentran en frutas y vegetales

Variance prediction for population size estimation

Design unbiased estimation of population size by stereological methods is an efficient alternative to automatic computer vision methods, which are generally biased. Moreover, stereological methods offer the possibility of predicting the error variance from a single sample. Here we explore the statistical performance of two alternative variance estimators on a dataset of 26 labelled crowd pictures. The empirical mean square errors of the variance predictors are compared by means of Monte Carlo resampling

Evaluating the pharmacological response in fluorescence microscopy images: The Δm algorithm

Current drug discovery procedures require fast and effective quantification of the pharmacological response evoked in living cells by agonist compounds. In the case of G-protein coupled receptors (GPCRs), the efficacy of a particular drug to initiate the endocytosis process is related to the formation of endocytic vesicles or endosomes and their subsequent internalisation within intracellular compartments that can be observed with high spatial and temporal resolution by fluorescence microscopy techniques. Recently, an algorithm has been proposed to evaluate the pharmacological response by estimating the number of endosomes per cell on time series of images. However, the algorithm was limited by the dependence on some manually set parameters and in some cases the quality of the image does not allow a reliable detection of the endosomes. Here we propose a simple, fast and automated image analysis method?the ?m algorithm- to quantify a pharmacological response with data obtained from fluorescence microscopy experiments. This algorithm does not require individual object detection and computes the relative increment of the third order moment in fluorescence microscopy images after filtering with the Laplacian of Gaussian function. It was tested on simulations demonstrating its ability to discriminate different experimental situations according to the number and the fluorescence signal intensity of the simulated endosomes. Finally and in order to validate this methodology with real data, the algorithm was applied to several time-course experiments based on the endocytosis of the mu opioid receptor (MOP) initiated by different agonist compounds. Each drug displayed a different ?m sigmoid time-response curve and statistically significant differences were observed among drugs in terms of efficacy and kinetic parameters

Hidrocarburos aromáticos policíclicos (HAPs) (I): Toxicidad, exposición de la población y alimentos implicados

Food is one of the main exogenous sources of genotoxic compounds. In heated food products, polycyclic aromatic hydrocarbons (PAHs) represent a priority group of genotoxic, mutagenic and/or carcinogenic chemical pollutants with adverse long-term health effects. People can be exposed to these compounds through different environments and via various routes: inhalation, ingestion of foods and water and even percutaneously. The presence of these compounds in food may be due to environmental contamination, to industrial handling and processing of foods and to oil processing and refining. The highest levels of these compounds are found in smoked foods, in seafood which is found in polluted waters, in grilled meats and, to a lesser extent, in vegetable fats and oils. Lower levels of PAHs are found in vegetables and in cereals and its products.Los alimentos constituyen una de las principales fuentes exógenas de compuestos genotóxicos. En los alimentos calentados, los hidrocarburos aromáticos policíclicos (HAPs) representan un grupo prioritario de contaminantes químicos genotóxicos, mutagénicos y/o cancerígenos con efectos adversos a largo plazo para la salud. Las personas pueden estar expuestas a estos compuestos en numerosos ambientes y a través de diferentes vías: inhalatoria, alimentos, agua e incluso percutánea. La presencia de estos compuestos en los alimentos puede deberse a la contaminación ambiental, la manipulación y el procesado industrial de los alimentos y a los procesos de extracción y refinado del aceite. Los niveles máximos de estos compuestos los encontramos en los alimentos ahumados, en los mariscos que se encuentran en aguas contaminadas, en las carnes a la parrilla y en menor medida en las grasas vegetales y en los aceites. Niveles inferiores de HAPs están presentes en las verduras y las hortalizas y en los cereales y sus productos

Power and bandwidth allocation based on age of information metrics in satellite uplink channels

Communication links over satellites allow interconnecting very distant regions to provide service where the terrestrial networks are limited. In this scenario, it is of major importance to devise mechanisms accounting for the improved freshness of packets given the impact of large distances. Their analysis is particularly important when considering the deployment of sensors in remote areas, where satellite links may introduce a high delay in the communication system. In this respect, we report the use of age of information (AoI) metrics to evaluate users' allocation mechanisms. We use power-domain non-orthogonal multiple access (NOMA) as an alternative to orthogonal multiple access (OMA) to optimally reduce the age of received packets. We derive the proper formulation to account for a fairness condition when pairing users accounting for both; the user's needs to transmit information and the allowable link rate. Comparative results are provided by numerically evaluating the solution for NOMA and OMA accounting for the peak age of information (PAoI) metric. We show that the resource allocation mechanisms in NOMA results in less PAoI (40%) compared to OMA. We remark this result through extensive numerical simulations based on actual uplink satellite communication links accounting for 500 users.This work has been supported by the Spanish National Project IRENE (PID2020-115323RB-C31, PID2020- 115323RB-C33 / AEI / 10.13039/501100011033).Peer ReviewedPostprint (author's final draft

Moisture loss kinetics and microstructural changes in eggplant (Solanum melongena L.) during conventional and ultrasonically assisted convective drying

[EN] The overall aim of this study was to assess the moisture loss kinetics and the structural changes induced by both conventional and ultrasonically assisted convective drying of eggplant tissue. Three sets of drying experiments (at 40 ◦C and 1 m/s) were carried out: conventional air drying and ultrasonically assisted drying at two different levels of applied ultrasonic power, 45 and 90 W. The microstructure of the dried samples was studied by scanning electron microscopy. The application of ultrasound during the convective drying of eggplant led to a significant reduction of the drying time. The ultrasonic effect was dependent on the power applied, thus, the higher the power, the faster the moisture loss. The microstructure of eggplant endocarp was greatly affected during conventional air drying, probably due to the long drying times. This microstructure was better preserved after the application of a moderate ultrasonic power (45 W), due to the shorter drying time and the mild mechanical effects of ultrasound on the endocarp cells.The authors acknowledge the financial support of the Ministerio de Economia y Competitividad (MINECO) of Spain from the project DPI2009-14549-C04-04.Puig Gómez, CA.; Pérez Munuera, IM.; Carcel Carrión, JA.; Hernando Hernando, MI.; García Pérez, JV. (2012). Moisture loss kinetics and microstructural changes in eggplant (Solanum melongena L.) during conventional and ultrasonically assisted convective drying. Food and Bioproducts Processing. 90:624-632. doi:10.1016/j.fbp.2012.07.001S6246329