Multibeam adaptive array

To achieve adaptive multibeamforming to allow reconfiguration in SSW-TDMA satellite communications, a system for narrow band adaptive multibeamforming is described in this work. The signal processor allows an unconstrained array to form independent beams for the impinging directions without any prior knowledge of them. The simultaneous use of constant modulus and minimum variance (least-mean square loops) is done by an especial policy of master-slave for subarrays or local beams which acts both in acquisition and tracking. The results of simulations confirm the theoretical work.Peer ReviewedPostprint (published version

Extracción en lazo abierto de la fase de portadora en sistemas de demodulación coherente

The Burst transmision of digital data, using Time Division Multiple Access, has became one of the more usual techniques in the satellite communications systems. In this paper, a method for carrier phase extraction in a coherent demodulation TDMA system is presented, with a 9,6 Kbits transmision rate. It is compared with other existent methods.Peer ReviewedPostprint (published version

Neural nets filters: integrated coding and signaling in communication systems

The authors describe the potential of neural net filters in communication systems. They consider applications of neural networks in those fields associated with communications where time-varying linear systems need to be used; the structure of the neural net considered is the multiple-layer feed-forward network. It is shown that an FIR (finite impulse response) filter with finite representation of its output could be viewed as a two-layer neural net. Experiments on the equalization of nonlinear communication channels with memory are reported, demonstrating the potential of neural networks in integrated tools for signal processing and decodingPeer ReviewedPostprint (published version

The work design contribution to educational workers' sustainable wellbeing and performance patterns

Brazilian education faces difficulties relating to performance and illness, suggesting that the characteristics of the work can affect both variables. This study aims to describe the work characteristics that increase the odds of having happy–productive patterns in education workers. A total of 4,598 employees of the Secretariat of Education of the Federal District (SEEDF) participated in the research, answering questionnaires about work design (Brazilian version, with 18 factors), wellbeing (containing three factors), and performance. The results showed that task, social, and contextual characteristics increase the probability of being in the happy–productive pattern, and specifically, Social Support, Feedback from Others, Task Significance, Task Identity, and Autonomy, in this order, should be considered for intervention purposes

Association Between Endometriosis and Preterm Birth in Women With Spontaneous Conception or Using Assisted Reproductive Technology: A Systematic Review and Meta-Analysis of Cohort Studies

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado.OBJECTIVE: To perform a systematic review and meta-analysis to estimate the effect of endometriosis on preterm birth (PB) risk. METHODS: Searches were conducted in PubMed-MEDLINE, Embase, Scopus, Web of Science, Cochrane Library, Google Scholar, and SciELO for studies published in all languages from inception through April 2017. We included cohort studies evaluating pregnant women with and without endometriosis and conception either by spontaneous conception (SC) or with assisted reproductive technology (ART). Primary outcome was PB (<37 weeks), and secondary outcomes were intrauterine growth restriction (IUGR), low birthweight, small for gestational age (SGA), and birthweight. Pooled odds ratios (ORs) and its 95% confidence interval (CI) were calculated as effects, and random-effects models were used for meta-analyses. Risk of bias was assessed with the Newcastle-Ottawa Scale, and heterogeneity of effects among studies was described with the I2 statistic. RESULTS: We identified 9 cohort studies including a total of 1 496 715 pregnancies (13 798 with endometriosis diagnosis). In women with endometriosis, the PB risk was significantly increased in both SC (OR: 1.59; 95% CI: 1.32-1.90) and ART (OR: 1.43; 95% CI: 1.14-1.79). The SGA risk was increased in women with endometriosis (OR: 1.16; 95% CI: 1.05-1.28), while the IUGR and low birthweight risks and birthweight were not affected by endometriosis. CONCLUSION: Endometriosis is associated with increased PB risk in both SC and women who obtained pregnancy using ART. Prospective studies evaluating relevant outcomes are needed to confirm these results.Revisión por pare

Instalazio termiko hibrido baten energia- eta exergia-analisi dinamikoa

Climate change is modifying the energy demand everywhere. This influences the way in which energy demand supply systems are sized and how they work, especially in systems designed for the long term. Thus, it is urgent to know the sources of renewable energy to exploit them in a sustainable way and to do so with systems that adapt their exploitation to the requirements of climate change. The system that mixes these two requirements is the heat pump. The heat pump is capable of exploiting energy sources close to the surrounding temperature and is an ideal technology for meeting the energy needs of applications with low thermal requirements. The energy demand of buildings is high, but domestic hot water for buildings and heating have a low thermal demand. Thus, the use of heat pumps in the thermal facilities of buildings ensures the energy transition and the flexibility to adapt to the new climate change scenario. In order to reduce energy demand as much as possible, it is necessary to know the degradation mechanisms of energy resources. Energy and exergy analyses are very useful tools to know the exergy destruction and the energy and exergy efficiency of a system. This paper presents a real hybrid facility containing in the generation block a ground-coupled heat pump and a gas boiler. The facility supplies a building with domestic hot water and heating. The dynamic simulation of the facility has been carried out with TRNSYS software and data for the application of energy and exergy analysis have been obtained. For the first time, a dynamic exergy analysis has been applied to a system consisting of a ground source heat pump and a gas boiler. The results obtained indicate that 71% of the exergy destruction occurs in the boiler and the exergy efficiency of the heat pump is 6%. The results obtained allow to improve the energy performance of this thermal facility.; Klima-aldaketaren eraginez, tokian tokiko energia-eskaria aldatzen ari da. Horrek energia-eskaria asetzeko sistemen dimentsionamenduan eta operazio-moduan eragiten du; batez ere, epe luzerako proiektatzen diren sistemetan. Hala, premiazkoa da jatorri berriztagarria duten energia-iturriak ezagutzea, modu jasangarrian ustiatzea eta ustiaketa klima-aldaketaren eskakizunetara egokituko diren sistemekin egitea. Bero-ponpak bi baldintza horiek bateratzen ditu. Bero-ponpa inguru-tenperaturatik gertu dauden energia-iturriak ustiatzeko gai da eta eskakizun termiko baxua duten aplikazioen energia-beharrak asetzeko aproposa den teknologia da. Eraikinen energia-eskaria handia da, baina eraikinetarako ur bero sanitarioak eta berokuntzak eskakizun termiko baxua dute. Horrela, eraikinen instalazio termikoetan bero-ponpa edukitzeak, energia- trantsizioa eta klima-aldaketaren agertoki berrira egokitzeko malgutasuna bermatzen ditu. Energia-eskaria ahalik eta gehien murrizteko, energia-baliabideen degradatze-mekanismoak ezagutu behar dira. Energia- eta exergia-analisiak oso tresna erabilgarriak dira sistema baten exergia-suntsiketa eta energia- eta exergia-efizientzia ezagutzeko. Lan honetan, sorkuntza-sisteman lurzorura akoplatutako bero-ponpa bat eta gas-galdara bat dauzkan instalazio hibrido erreal bat aurkezten da. Instalazioak ur bero sanitarioz eta berokuntzaz hornitzen du eraikin bat. TRNSYS softwarearen bitartez, instalazioaren simulazio dinamikoa burutu da eta energia- eta exergia-analisia aplikatzeko datuak lortu dira. Lehen aldiz, exergia-analisi dinamikoa aplikatu da. Lortutako emaitzen arabera, exergia-suntsiketaren % 78 galdaran gertatzen da, eta bero-ponparen exergia-efizientzia % 46koa da. Lortutako emaitzek zabaldu egiten dute instalazio termiko honen energia-portaera hobetzeko bidea

Connectivity between coastal lagoons and sea: asymmetrical effects on assemblages' and populations' structure

Connectivity among marine populations plays a fundamental role in the dynamic of metapopulations and communities. Moreover, genetic connectivity is important for the evolutionary history and adaptive capability of species while demographic connectivity is essential to maintain ecological processes. In coastal lagoons, isolation degree or confinement is considered the main factor structuring biological assemblages. These environments also function as nursery areas for many marine species that colonize the lagoons as larvae or juveniles, returning to the sea for reproduction. It is therefore essential to know the connectivity between lagoons and sea for the management of biodiversity and the exploitation of coastal living resources. This work anases the role that connectivity between coastal lagoons and sea plays in the assemblages and subpopulations structure of the first. To this purpose, a finite element hydrodynamic model was used coupled with a lagrangian module to simulate the potential exchange of organisms between Mar Menor lagoon (Western Mediterranean) and the adjacent sea. Connectivity parameters from 40 stations, located inside and outside the Mar Menor, have been estimated. The outcomes of the eight simulations carried out were compared with field data, including ichthyoplankton species composition and genetic fluxes in 6 species with different life stories. The results suggest that pelagic larval phases are longer than expected or the species can extend PLD within certain limits if the conditions for the settlement are not adequate. Repetition can improve the chance of self-recruitment, coupling larval duration, competency period and finding the adequate location for settlement. The results also show that connectivity between all lagoon and Mediterranean stations is very low and is independent of geographical distance. There is a strong asymmetry in the probability of receiving particles, being lower the probability of colonization of the lagoon stations from the sea than vice versa. Despite its low values, connectivity can explain up to 65% of the similarities in species composition of the ichthyoplankton and between 30 and 96% of the variance in genetic differentiation of the studied species. The low value of connectivity and colonization rates is enough, however, to maintain the genetic fluxes between populations and, at the same time, restricted connectivity can play an important role in maintaining high diversity and heterogeneous assemblage structure

ARMA model maximum entropy power spectral estimation

Peer ReviewedPostprint (published version