264 research outputs found

    Evidence of large areas of stratified waters in the SMOS Sea Surface Salinity maps

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    Ocean Salinity Conference, 6-9 June 2022, New York, USAPeer reviewe

    On the computation of reducible invariant tori on a parallel computer

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    We present an algorithm for the computation of reducible invariant tori of discrete dynamical systems that is suitable for tori of dimensions larger than 1. It is based on a quadratically convergent scheme that approximates, at the same time, the Fourier series of the torus, its Floquet transformation, and its Floquet matrix. The Floquet matrix describes the linearization of the dynamics around the torus and, hence, its linear stability. The algorithm presents a high degree of parallelism, and the computational effort grows linearly with the number of Fourier modes needed to represent the solution. For these reasons it is a very good option to compute quasi-periodic solutions with several basic frequencies. The paper includes some examples (flows) to show the efficiency of the method in a parallel computer. In these flows we compute invariant tori of dimensions up to 5, by taking suitable sections

    Understanding the Evolutionary Relationships and Major Traits of \u3cem\u3eBacillus\u3c/em\u3e through Comparative Genomics

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    Background: The presence of Bacillus in very diverse environments reflects the versatile metabolic capabilities of a widely distributed genus. Traditional phylogenetic analysis based on limited gene sampling is not adequate for resolving the genus evolutionary relationships. By distinguishing between core and pan-genome, we determined the evolutionary and functional relationships of known Bacillus. Results: Our analysis is based upon twenty complete and draft Bacillus genomes, including a newly sequenced Bacillus isolate from an aquatic environment that we report for the first time here. Using a core genome, we were able to determine the phylogeny of known Bacilli, including aquatic strains whose position in the phylogenetic tree could not be unambiguously determined in the past. Using the pan-genome from the sequenced Bacillus, we identified functional differences, such as carbohydrate utilization and genes involved in signal transduction, which distinguished the taxonomic groups. We also assessed the genetic architecture of the defining traits of Bacillus, such as sporulation and competence, and showed that less than one third of the B. subtilis genes are conserved across other Bacilli. Most variation was shown to occur in genes that are needed to respond to environmental cues, suggesting that Bacilli have genetically specialized to allow for the occupation of diverse habitats and niches. Conclusions: The aquatic Bacilli are defined here for the first time as a group through the phylogenetic analysis of 814 genes that comprise the core genome. Our data distinguished between genomic components, especially core vs. pan-genome to provide insight into phylogeny and function that would otherwise be difficult to achieve. A phylogeny may mask the diversity of functions, which we tried to uncover in our approach. The diversity of sporulation and competence genes across the Bacilli was unexpected based on previous studies of the B. subtilis model alone. The challenge of uncovering the novelties and variations among genes of the non-subtilis groups still remains. This task will be best accomplished by directing efforts toward understanding phylogenetic groups with similar ecological niches

    Validation of SMOS L2 and L3 soil moisture products over the Duero Basin at different spatial scales

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    36th International Symposium on Remote Sensing of Environment, 11-15 May 2015, Berlin, Germany.-- 6 pages, 3 figures, 3 tablesAn increasing number of permanent soil moisture measurement networks are nowadays providing the means for validating new remotely sensed soil moisture estimates such as those provided by the ESA’s Soil Moisture and Ocean Salinity (SMOS) mission. Two types of in situ measurement networks can be found: small-scale (100–10000 km2), which provide multiple ground measurements within a single satellite footprint, and large-scale (>10000 km2), which contain a single point observation per satellite footprint. This work presents the results of a comprehensive spatial and temporal validation of a long-term (January, 2010 to June, 2014) dataset of SMOS-derived soil moisture estimates using two in situ networks within the Duero basin (Spain). The first one is the Soil Moisture Measurement Stations Network of the University of Salamanca (REMEDHUS), which has been extensively applied for validation of soil moisture remote sensing observations, including SMOS. REMEDHUS can be considered within the small-scale network group (1300 km2). The other network started from an existing meteorological network from the Castilla y León region, where soil moisture probes were incorporated in 2012. This network can be considered within the large-scale group (65000 km2). Results from comparison to in situ show that the new reprocessed L2 product (v5.51) improves the accuracy of former soil moisture retrievals, making them suitable for developing new L3 products. Validation based on comparisons between dense/sparse networks showed that temporal patterns on soil moisture are well reproduced, whereas spatial patterns are difficult to depict given the different spatial representativeness of ground and satellite observationsThis work was supported by the Spanish Ministry of Economy and Competitiveness (Project AYA2012-39356-C05). Ángela Gumuzzio acknowledges support from the FPI grant BES-2011-050439Peer Reviewe

    Operational monitoring of water quality with a Do-It-Yourself modular instrument

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    We analyze the efficacy of using a Do-It-Yourself (DIY) modular instrument to estimate the diffuse attenuation coefficient (Kd) of photosynthetically active radiation (PAR), which can be used for operational oceanography in turbid shallow waters. This parameter evaluates the water transparency, as it summarizes several water components providing an indicator for water quality. Historically, water transparency has been measured with a simple and inexpensive tool: the Secchi disk. Although it contributes a valuable index of visual water clarity, the quality of its measurements is user-dependent, and it does not enable the automatic monitoring of the water quality. For this reason, we need electronic devices to get accurate measures and facilitate long-term evaluations for water quality monitoring. This paper has two main objectives: First, to present the KduPRO, a low-cost and DIY moored instrument. The KduPRO is an evolution of the KdUINO buoy, that provides an estimation of the water transparency in coastal areas and continental waters, with an automatic quality control parameter that makes this sensor suitable for operational observing systems; and second, to provide a replicability analysis associated to the uncertainty of its Kd estimations. This instrument is based on a modular system of light sensors, independent of each other, measuring the irradiance at different depths. This study analyses the performance of the KduPRO with other reference commercial instruments, the performance between different modules of the same system and finally, a case study of measuring the water quality in Loch Leven (a lake in Scotland). The affordable cost, ease of use and measurement repeatability make this instrument a potentially valuable tool for anyone interested in monitoring water quality

    Fibroma óseo juvenil: a propósito de un caso clínico

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    Se presenta el caso clínico de un paciente de 8 años de edad con un fibroma osificante juvenil en el ángulo mandibular derecho y un quiste radicular en el ángulo mandibular izquierdo, los cuales producían un importante abombamiento a nivel de los ángulos mandibulares e impedían la correcta erupción de los primeros molares inferiores. Tras el estudio clínico y radiológico ( Ortopantomografía y Scan dental del maxilar inferior), se llevó a cabo el correspondiente tratamiento quirúrgico (quistectomía y remodelación de los mismos) y el estudio histopatológico. Aunque el fibroma óseo juvenil es una entidad clínica poco frecuente, debido al comportamiento local agresivo y a la recidiva que tiene, es importante realizar un diagnóstico precoz, un tratamiento adecuado y, sobre todo, un seguimiento del paciente a lo largo del tiempo.We present the case of an 8-year-old patient with a juvenile ossifying fibroma in the right mandibular angle and a radicular cyst in the left mandibular angle, which produced a major swelling at the level of the mandibular angles and prevented the correct eruption of the lower first molars. After the clinical and radiological (panoramic X-ray and dental scan of the mandible), the corresponding surgical treatment (cystectomy and remodelling) and histopathological study were carried out. Although juvenile ossifying fibroma is an uncommon clinical entity, its aggressive local behaviour and high recurrence rate mean that it is important to make an early diagnosis, apply the appropriate treatment and, especially, follow the patient up over the long term

    Nodal sampling: a new image reconstruction algorithm for SMOS

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    Soil moisture and ocean salinity (SMOS) brightness temperature (TB) images and calibrated visibilities are related by the so-called G -matrix. Due to the incomplete sampling at some spatial frequencies, sharp transitions in the TB scenes generate a Gibbs-like contamination ringing and spread sidelobes. In the current SMOS image reconstruction strategy, a Blackman window is applied to the Fourier components of the TBs to diminish the amplitude of artifacts such as ripples, as well as other Gibbs -like effects. In this paper, a novel image reconstruction algorithm focused on the reduction of Gibbs -like contamination in TB images is proposed. It is based on sampling the TB images at the nodal points, that is, at those points at which the oscillating interference causes the minimum distortion to the geophysical signal. Results show a significant reduction of ripples and sidelobes in strongly radio-frequency interference contaminated images. This technique has been thoroughly validated using snapshots over the ocean, by comparing TBs reconstructed in the standard way or using the nodal sampling (NS) with modeled TBs. Tests have revealed that the standard deviation of the difference between the measurement and the model is reduced around 1 K over clean and stable zones when using NS technique with respect to the SMOS image reconstruction baseline. The reduction is approximately 0.7 K when considering the global ocean. This represents a crucial improvement in TB quality, which will translate in an enhancement of the retrieved geophysical parameters, particularly the sea surface salinity.Peer ReviewedPostprint (author's final draft

    Water quality monitoring program through the KduSTICK, a low-cost and Do-It-Yourself instrument connected by the Internet of Things

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    Monitoring water transparency provides an indicator of the environmental status of the water body. One parameter to estimate the water transparency is the light difuse attenuation coefcient (Kd). In the framework of the H2020 project MONOCLE (Multiscale Observation Networks for Optical monitoring of Coastal waters, Lakes and Estuaries), we have developed an improved version of the KdUINO (Bardaji et al., 2016) consisting of a moored instrument used to assess water transparency. This new version, the KduSTICK, estimates Kd near the surface in real-time following these specifcations: cost-efective, portable, real-time monitoring and easy to use with minimal training. This instrument transmits data by using the Internet of Things (IoT) networks. In particular, our research group participates in the initiative “The Things Network” (TTN), an IoT network based on LoRaWAN. This device is easy to deploy and maintain, and it is suitable for citizen-science based water quality monitoring programs.Peer ReviewedObjectius de Desenvolupament Sostenible::6 - Aigua Neta i Sanejament::6.3 - Per a 2030, millorar la qualitat de l’aigua mitjançant la reducció de la contaminació, l’eliminació dels abocaments i la reducció al mínim de la descàrrega de materials i productes químics perillosos, la reducció a la meitat del percentatge d’aigües residuals sense tractar, i un augment substancial a escala mundial del reciclat i de la reutilització en condicions de segureta
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