4,541 research outputs found
On the Provisioning of Mobile Digital Terrestrial TV Services to Vehicles with DVB-T
(c) 2012 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works[EN] Most of the DVB-T (Digital Video Broadcasting -Terrestrial) networks deployments worldwide have been designed for fixed rooftop antennas and high transmission capacity, not providing good coverage level for vehicular mobile reception. This letter analyzes how to combine different technical solutions, so far studied individually, in order to increase the robustness of the transmission for vehicular reception to provide in-band mobile services. In particular, we consider: receive antenna diversity, hierarchical modulation, and Application Layer Forward Error Correction (AL-FEC). Performance evaluation results have been obtained by means of simulations, laboratory tests, and field measurements in the commercial DVB-T network of the city of Valencia (Spain). The paper shows that the combined usage of these solutions can compensate the impairments caused by the mobility of the receivers, such as signal fast fading, Doppler shift, the poor coverage at ground level and the utilization of lower gain antennas; being possible to provide mobile DVB-T services to vehicles in networks dimensioned for fixed rooftop reception.This work was supported in part by the Spanish Ministry of Industry, Tourism and Commerce under the project AV-MOV (TSI-020301-2009-11).López Sánchez, J.; Gomez-Barquero, D.; Gozálvez Serrano, D.; Cardona Marcet, N. (2012). On the Provisioning of Mobile Digital Terrestrial TV Services to Vehicles with DVB-T. IEEE Transactions on Broadcasting. 58(4):642-647. https://doi.org/10.1109/TBC.2012.2202034S64264758
An Ecosystem Approach to the Role of Fish Farming in Coastal Areas
Coastal ecosystems put up most of the impacts from human activities in the sea. Generally, assessment based on a unispecific ecological group and/or habitat reflects only a fraction of what is happening in the ecosystem, and usually it is biased by the spatial and temporal variability at small scales. This is more evident when several human activities co-exist in the same area and interact synergically among them and with the natural structure and dynamics of the ecosystem. An ecosystemic assessment can combine several ecological groups, habitats, processes and/or activities, and offer a more holistic picture about the structure and dynamics of the considered coastal area.This study was partially funded by Spanish Ministry of Science Grant (Project FATFISH CTM2009-14362-C02-01). JTBS thanks to Conselleria d'Educació, Generalitat Valenciana, for financing the visit to La Paz during 2012. FAS thanks support to visit the University of Alicante during 2013
¿Son el bajo nivel de condición física y la obesidad dos características del adolescente con síndrome de Down?
Introduction: “Obesity” is considered a feature of
youth with DS but whether “low physical fitness” is also a
feature is unknown.
Objective: The aim of this case-control study was to
compare the levels of fatness and fitness in adolescents
with and without DS.
Methods: Participants included 17 (5 girls) adolescents
with DS aged 12-18 years and a control group of 94 (45
girls) adolescents without DS aged 12-16 years. The
ALPHA health-related fitness test battery for children
and adolescents was selected to assess fatness and fitness
in both groups.
Results: There were no differences in levels of fatness
between groups (all P > 0.27). Adolescents with DS had
lower levels of fitness in all the tests than adolescents
without DS (all P < 0.001).
Conclusion: Adolescents with DS have similar levels of
fatness and lower levels of fitness than their peers without
DSIntroducción: La obesidad es considerada una característica
de los jóvenes con SD, sin embargo se desconoce si
la “baja condición física” también lo es.
Objetivo: Comparar los niveles de obesidad y condición
física en adolescentes con y sin SD.
Métodos: Participaron 17 adolescentes (5 niñas) con SD
de 12 a 18 años y un grupo control de 94 (45 niñas) adolescentes
sin SD de 12-16 años de edad. La batería de condición
física ALPHA relacionada con la salud para niños y
adolescentes fue seleccionada para evaluar la obesidad y
la condición física en ambos grupos.
Resultados: No se encontraron diferencias en los niveles
de obesidad entre grupos (P > 0,27). Los adolescentes
con SD tuvieron niveles más bajos de condición física en
todos los test en comparación con los adolescentes sin SD
(P < 0,001).
Conclusión: Los adolescentes con SD tienen niveles
similares de obesidad y menores de condición física que
sus compañeros sin SD.The UP&DOWN study was supported by the
Spanish Ministry of Economy and Competitiveness
(DEP 2010-21662-C04). JRR was supported by a
contract from the Spanish Ministry of Science and
Innovation (RYC-2010-05957
Hidromet: A Cloud-Based EWS Platform For Real Time Urban Flood Warning
Urban real time flood’s Early Warning Systems have been traditionally based on the use of punctual precipitation observations (raingauges) to model the sewer network’s behaviour by means of hydraulic models. Since a key issue in the EWS is the leadtime in detecting potential risks, Hidromet takes advantage of radar nowcasting techniques to feed a hydraulic model, not only with observed precipitation by raingauges, but also with forecasted precipitation for the following few hours. Radar nowcasting techniques allow forecasting the precipitation with a high degree of accuracy. This fact, together with the rapid update of the forecasts (typically around 10 minutes), makes radars a good tool for urban real time hydraulics allowing for more accurate results and to increase the leadtime in which potential risks are detected. In Hidromet, the hydraulic model is encapsulated in the cloud, and run with updated data (observations and forecasts) every time those are available. The network’s operators are able to configure the critical points in the sewer network to be monitored, and define individually the warning thresholds. Sensors data have also been integrated seamless in the system. The access to the platform is web-based and protected under different levels of passwords. Therefore it is fully accessible from any connected device and not limited to those ones receiving the sensors data. The web also allows configuring the actions to be triggered when the different warning levels are reached (SMSs, emails, etc.) under profiles of users. Up to now, the platform has been validated in four cities of Spain and is under implementation in Chile
High cooperativity coupling to nuclear spins on a circuit quantum electrodynamics architecture
Nuclear spins are candidates to encode qubits or qudits due to their isolation from magnetic noise and potentially long coherence times. However, their weak coupling to external stimuli makes them hard to integrate into circuit quantum electrodynamics architectures, the leading technology for solid-state quantum processors. Here, we study the coupling of 173Yb(III) nuclear spin states in an [Yb(trensal)] molecule to superconducting cavities. Experiments have been performed on magnetically dilute single crystals placed on the inductors of lumped-element LC superconducting resonators with characteristic frequencies spanning the range of nuclear and electronic spin transitions. We achieve a high cooperative coupling to all electronic and most nuclear [173Yb(trensal)] spin transitions, a necessary ingredient for the implementation of qudit protocols with molecular spins using a hybrid architecture
Physical Activity, Sitting Time, and Mortality From Inflammatory Diseases in Older Adults
Objective: The aim of this study was to examine the independent and combined associations of physical activity (PA) and sitting time (ST) with long-term mortality attributed to inflammatory causes other than cardiovascular disease (CVD) and cancer in a national cohort of older adults in Spain.Design: Prospective study.Setting and Participants: A cohort of 3,677 individuals (1,626 men) aged ≥60 years was followed-up during 14.3 years.Measures: At baseline, individuals reported PA and ST. The study outcome was death from inflammatory diseases when CVD or cancer mortality was excluded. This outcome was classified into infectious and non-infectious conditions. Analyses were performed with Cox regression and adjusted for PA, ST, and other main confounders (age, sex, educational level, smoking, alcohol consumption, body mass index, and chronic conditions).Results: During follow-up, 286 deaths from inflammatory diseases (77 from infectious diseases) were identified. Compared to individuals who defined themselves as inactive/less active, mortality from inflammatory diseases was lower in those who were moderately active (hazard ratio [HR] = 0.67, 95% confidence interval [CI] = 0.50–0.90) or very active (HR = 0.48, 95%CI = 0.33–0.68), independently of ST. Also, being seated ≥7 h/d vs. <7 h/d was linked to higher mortality (HR = 1.38, 95%CI = 1.02–1.87). The largest risk of mortality was observed in inactive/less active individuals with ST≥7 h/d (HR = 2.29, 95%CI = 1.59–3.29) compared to those with moderate/very PA and ST <7 h/d. Low PA and high ST were consistently associated with a higher risk of mortality from non-infectious inflammatory causes. Associations of PA and ST with mortality from infectious inflammatory causes showed a similar trend, but most of them did not reach statistical significance.Conclusions: Low PA and high ST were independently associated with higher mortality from inflammatory diseases other than CVD or cancer in older adults. Interventions addressing simultaneously both behaviors could have greater benefits than those focusing on only one of them
Collecting wild potato species (Solanum sect. Petota) in Peru to enhance genetic representation and fill gaps in ex situ collections
Crop wild relatives (CWRs) are important sources of novel genes, due to their high variability of response to biotic and abiotic stresses, which can be invaluable for crop genetic improvement programs. Recent studies have shown that CWRs are threatened by several factors, including changes in land-use and climate change. A large proportion of CWRs are underrepresented in genebanks, making it necessary to take action to ensure their long-term ex situ conservation. With this aim, 18 targeted collecting trips were conducted during 2017/2018 in the center of origin of potato (Solanum tuberosum L.), targeting 17 diverse ecological regions of Peru. This was the first comprehensive wild potato collection in Peru in at least 20 years and encompassed most of the unique habitats of potato CWRs in the country. A total of 322 wild potato accessions were collected as seed, tubers, and whole plants for ex situ storage and conservation. They belonged to 36 wild potato species including one accession of S. ayacuchense that was not conserved previously in any genebank. Most accessions required regeneration in the greenhouse prior to long-term conservation as seed. The collected accessions help reduce genetic gaps in ex situ conserved germplasm and will allow further research questions on potato genetic improvement and conservation strategies to be addressed. These potato CWRs are available by request for research, training, and breeding purposes under the terms of the International Treaty for Plant Genetic Resources for Food and Agriculture (ITPGRFA) from the Instituto Nacional de Innovacion Agraria (INIA) and the International Potato Center (CIP) in Lima-Peru
Study and Evolution of the Dune Field of La Banya Spit in Ebro Delta (Spain) Using LiDAR Data and GPR
La Banya spit, located at the south of the River Ebro Delta, is a sandy formation, developed by annexation of bars forming successive beach ridges, which are oriented and modeled by the eastern and southern waves. The initial ridges run parallel to the coastline, and above them small dunes developed, the crests of which are oriented by dominant winds, forming foredune ridges and barchans. This study attempted to test a number of techniques in order to understand the dune dynamic on this coastal spit between 2004 and 2012: LiDAR data were used to reconstruct changes to the surface and volume of the barchan dunes and foredunes; ground-penetrating radar was applied to obtain an image of their internal structure, which would help to understand their recent evolution. GPS data taken on the field, together with application of GIS techniques, made possible the combination of results and their comparison. The results showed a different trend between the barchan dunes and the foredunes. While the barchan dunes increased in area and volume between 2004 and 2012, the foredunes lost thickness. This was also reflected in the radargrams: the barchan dunes showed reflectors related to the growth of the foresets while those associated with foredunes presented truncations associated with storm events. However, the global balance of dune occupation for the period 2004-2012 was positive
Optimal coupling of Ho W<sub>10 molecular magnets to superconducting circuits near spin clock transitions
A central goal in quantum technologies is to maximize GT2, where G stands for the coupling of a qubit to control and readout signals and T2 is the qubit’s coherence time. This is challenging, as increasing G (e.g., by coupling the qubit more strongly to external stimuli) often leads to deleterious effects on T2. Here, we study the coupling of pure and magnetically diluted crystals of Ho W10 magnetic clusters to microwave superconducting coplanar waveguides. Absorption lines give a broadband picture of the magnetic energy level scheme and, in particular, confirm the existence of level anticrossings at equidistant magnetic fields determined by the combination of crystal field and hyperfine interactions. Such “spin clock transitions” are known to shield the electronic spins against magnetic field fluctuations. The analysis of the microwave transmission shows that the spin-photon coupling also becomes maximum at these transitions. The results show that engineering spin-clock states of molecular systems offers a promising strategy to combine sizable spin-photon interactions with a sufficient isolation from unwanted magnetic noise sources
Imaging Thermal Anomalies in Hot Dry Rock Geothermal Systems from Near-Surface Geophysical Modelling
Convective hydrothermal systems have been extensively studied using electrical and electromagnetic methods given the strong correlation between low conductivity anomalies associated with hydrothermal brines and high temperature areas. However, studies addressing the application of similar geophysical methods to hot dry rock geothermal systems are very limited in the literature. The Timanfaya volcanic area, located on Lanzarote Island (Canary Islands), comprises one of these hot dry rock systems, where ground temperatures ranging from 250 to 605 ◦C have been recorded in pyroclastic deposits at shallow (<70m) depths. With the aim of characterizing the geophysical signature of the high ground temperature areas, three different geophysical techniques (ground penetrating radar, electromagnetic induction and magnetic prospecting) were applied in a well-known geothermal area located inside Timanfaya National Park. The area with the highest ground temperatures was correlated with the location that exhibited strong ground penetrating radar reflections, high resistivity values and low magnetic anomalies. Moreover, the high ground temperature imaging results depicted a shallow, bowl-shaped body that narrowed and deepened vertically to a depth greater than 45 m. The ground penetrating radar survey was repeated three years later and exhibited subtle variations of the signal reflection patterns, or signatures, suggesting a certain temporal variation of the ground temperature. By identifying similar areas with the same geophysical signature, up to four additional geothermal areas were revealed. We conclude that the combined use of ground penetrating radar, electromagnetic induction and magnetic methods constitutes a valuable tool to locate and study both the geometry at depth and seasonal variability of geothermal areas associated with hot dry rock systems
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