1,762 research outputs found
Floral morphology and development in Aragoa (Plantaginaceae) and related members of the order Lamiales
Inflorescence and floral morphology and development were investigated in Aragoa (Plantaginaceae) and
related genera. Each inflorescence of Aragoa is a reduced, axillary raceme, on which the actinomorphic floral
apices generally arise successively. The inflorescences of Aragoa and Plantago are polytelic and lateral. The five
sepals emerge from the abaxial to the adaxial side of the floral apex, but at maturity, the calyx is
actinomorphic. The four stamens arise simultaneously and before emergence of the petals. The four petals
emerge unidirectionally united, but the corolla becomes actinomorphic. Aestivation is cochlear ascendent. The
two united carpels initiate simultaneously. The abaxial-adaxial inception of the calyx and corolla during early
floral development in genera such as Aragoa, Digitalis, Plantago, and Veronica may indicate that the
zygomorphic condition is ancestral in those genera. The tetramerous corolla, which is actinomorphic during
middle and late development, and the presence of four stamens are possible synapomophies of the clade
(Aragoa þ Plantago). Pentamery of the calyx and corolla appears to be plesiomorphic in the broader Aragoa-
Angelonia clade. Characters related to development and morphology of inflorescences and flowers of Aragoa
are essentially similar to those found in Plantago, which is consistent with the molecular-based sister group
relationship between these genera.Peer reviewe
Channel Estimation and Hybrid Precoding for Frequency Selective Multiuser mmWave MIMO Systems
© 2018 IEEE. This version of the article has been accepted for publication, after peer review. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, 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 component of this work in other works. The Version of Record is available online at: https://doi.org/10.1109/JSTSP.2018.2819130[Abstract]: Configuring the hybrid precoders and combiners in a millimeter wave multiuser multiple-input multiple-output system is challenging in frequency selective channels. In this paper, we develop a system that uses compressive estimation on the uplink to configure precoders and combiners for the downlink. In the first step, the base station (BS) simultaneously estimates the channels from all the mobile stations on each subcarrier. To reduce the number of measurements required, compressed sensing techniques are developed that exploit common support on the different subcarriers. In the second step, exploiting reciprocity and the channel estimates the BS designs hybrid precoders and combiners. Two algorithms are developed for this purpose, with different performance and complexity tradeoffs: First, a factorization of the purely digital solution; and second, an iterative hybrid design. Extensive numerical experiments evaluate the proposed solutions comparing to the state-of-the-art strategies, and illustrating design tradeoffs in overhead, complexity, and performance.This work was supported in part by Xunta de Galicia
(ED431C 2016-045, ED341D R2016/012, ED431G/01, ED431G/04), in part by
AEI of Spain (TEC2015-69648-REDC, TEC2016-75067-C4-1-R, TEC2016-
75103-C2-2-R), in part by ERDF funds (AEI/FEDER, EU), and in part by the
National Science Foundation under Grant 1702800.Xunta de Galicia; ED431C 2016/045Xunta de Galicia; ED341D R2016/012Xunta de Galicia; ED431G/01Xunta de Galicia; ED431G/0
Design rules for antenna placement on MIMO systems
In recent works, it is demonstrated that, depending on the different spatial distributions and distance between elements, there exists a different true polarization diversity (TPD) configuration that provides a high improvement in terms of capacity. This means that it is necessary to choose the appropriate TPD configuration to maximize the multiple-input-multiple-output (MIMO) capacity. In this work, a genetic algorithm is used to optimize the element positions for four new different configurations in combination with the TPD technique. It is shown that, for some configurations, the same polarization option is always found to reach the maximum capacity. Based on this, some novel design rules are provided to maximize MIMO capacity when the area for placing the antennas is very small. This is the case for most of the wireless devices, where the antenna design and location is one of the latest design constraints to be taken into consideration in the device design
Model Predictive Control-Based Optimized Operation of a Hybrid Charging Station for Electric Vehicles
This paper presents an energy management system (EMS) based on a novel approach using model predictive control (MPC) for the optimized operation of power sources in a hybrid charging station for electric vehicles (EVs). The hybrid charging station is composed of a photovoltaic (PV) system, a battery, a complete hydrogen system based on a fuel cell (FC), electrolyzer (EZ), and tank as an energy storage system (ESS), grid connection, and six fast charging units, all of which are connected to a common MVDC bus through Z-source converters (ZSC). The MPC-based EMS is designed to control the power flow among the energy sources of the hybrid charging station and reduce the utilization costs of the ESS and the dependency on the grid. The viability of the EMS was proved under a long-term simulation of 25 years in Simulink, using real data for the sun irradiance and a European load profile for EVs. Furthermore, this EMS is compared with a simpler alternative that is used as a benchmark, which pursues the same objectives, although using a states-based strategy. The results prove the suitability of the EMS, achieving a lower utilization cost (-25.3%), a notable reduction in grid use (-60% approximately) and an improvement in efficiency
Recovering and harmonizing research cruises information
The IEO has maintained since late 60s, a local database with basic information on oceanographic campaigns, formerly known as ROSCOF reports, which were established in the framework of IODE initiatives, as a low-level inventory for future access to data. Technological advances in recent decades and different coordination activities between NODCs have favored the implementation of these reports in standardized digital formats (Cruise Summary Reports, CSR) that allow their integration in international repositories as SeaDataNet or POGO.
However, this inventory and cataloging activity has suffered ups and downs over 40 years of activity, changes in storage criteria and periods of less activity. In the search for a unique criterion that can last over time and that unifies this information as much as possible with the data generated in these campaigns, an exhaustive review of the existing information has been carried out
Evolución de los deltas submarinos de los ríos Guadalfeo y Adra en respuesta a las variaciones de los aportes sedimentarios
The Guadalfeo and the Adra submarine deltas off the northern coast of the Alboran Sea
have been built up under the direct influence of short and mountainous rivers. The area is subjected
to strong climatic seasonality, with sporadic winter torrential floods and high summer aridity. In
addition numerous anthropogenic activities have affected these systems, mostly during the last two
centuries. In order to decode the influence of climatic variability and anthropogenic impacts on
sediment supplies during the recent past, five sediment cores were collected from the Guadalfeo
and Adra submarine deltas. Benthic foraminiferal and sedimentological analyses, combined with
radiocarbon dating, were performed. The impact of torrential floods alternating with periods of low
rainfall or dry periods were recorded in the Adra and Guadalfeo prodeltas. Periods with low
abundance of benthic foraminifera and high amounts of coarse-grained sediments, were interpreted
as the result of enhanced sediment supply to the shelf triggered by major flood events. On the other
hand, periods with high amounts of fine-grained sediments and high abundances of colonizers and
opportunistic foraminiferal species indicate the establishment of new environments with distinct
ecological constraints. These environments were driven by lower sediment supplies during low
rainfall or dry periods. The most recent sedimentation seems to reflect the human interventions in
the rivers basins, such as deviation of the main river courses and dams construction, which reduced
the sediment input and promoted the deposition of shallow-water submarine deltas.Versión del edito
Assessing sea grass meadows condition at “El Río” Special Area of Conservation off “La Graciosa e Islotes del Norte de Lanzarote” Marine Reserve
Cymodosea nodosa meadows, known as ‘sebadales’ or ‘manchones’ at Canary Islands, represent EUNIS
habitat type code A5.5311, called Macaronesian Cymodocea beds. As it’s described at European
Union Habitats Directive (92/43/CEE) Annex 1, sea grass meadows belong to 1110 Sandbanks which
are slightly covered by seawater all the time, within Natura 2000 Network.
Several ‘sebadales’ throughout the archipelago are included in this Network as Special Areas of Conservation.
Cymodosea nodosa is regionally included within the Canary Islands Protected Species List
(Ley 4/2010), as a species ‘of interest to ecosystems of Canary Islands”, is usually found at a narrow
depth range (10 to 20 m of depth) and, on the whole, best structured meadows are settled at sheltered
bays, away from wave and current beating, flimsier at exposed areas. Deeper meadows are also sparser,
being C. nodosa replaced by green algae Caulerpa prolifera and Caulerpa racemosa, although mixed
algae-sea grass meadows are often found at different depths.
The project Assessment of marine flora (‘sebadal’, ma¨erl, ‘mujo’) of ‘La Graciosa e Islotes del Norte
de Lanzarote’ Marine Reserve, funded by ‘Viceconsejer´ıa de Pesca y Aguas de la Consejer´ıa de Agricultura,
Ganader´ıa, Pesca y Aguas’, Canary Islands Government, has had the aim of assessing sea grass
meadows condition and distribution at ‘El R´ıo’ Natura 2000 Network Special Area of Conservation, the
channel between La Graciosa and Lanzarote. ‘LA GRACIOSA 1311’ cruise was performed within the
framework of the project.
First of all previous information on sea grass shallow distribution (up to a depth of 20 m) in the study
area was reviewed. Afterwards, a tugged underwater video camera was used onboard of the Marine
Reserve Surveillance Vessel to update cartographic info performing a grid of sampling stations, covering
previously known distribution limits and verifying current presence/absence data and density.
Furthermore, population parameters were obtained in order to assess ‘sebadal’ condition. Fixed stations
were selected in regards to this process, and methodology applied on them was as follows: five radial
arranged transects were performed, identifying fragmentation (it estimates meadow continuity regarding
observed cover), density (mean value of several shoots number counts with 20 x 20 cm grids placed every
2 m), height (mean value in cm of 10 independent samples by transect) and fish and macroinvertebrate
species richness for each transect.
Graphic picture of sea grass density was made depending on two levels: low density level transects (
10 shoots/grid ( 50 shoots/m2) and medium density level transects ( 10 shoots/grid ( 50 shoots/m2).
Main study result is an estimate for the study region (‘El R´ıo’) and time of year of Cymodocea nodosa
population total distribution cover which comes to 1.640.076 m2, including a higher density ‘sebadal’ of
178.256 m2
Antimicrobial Susceptibility and Characterization of Resistance Mechanisms of Corynebacterium urealyticum Clinical Isolates
Corynebacterium urealyticum is a non-diphtherial urease-producing clinically relevant corynebacterial, most frequently involved in urinary tract infections. Most of the C. urealyticum clinical isolates are frequently resistant to several antibiotics. We investigated the susceptibility of 40 C. urealyticum isolated in our institution during the period 2005-2017 to eight compounds representative of the main clinically relevant classes of antimicrobial agents. Antimicrobial susceptibility was determined by the Epsilometer test. Resistance genes were searched by PCR. All strains were susceptible to vancomycin whereas linezolid and rifampicin also showed good activity (MICs90 = 1 and 0.4 mg/L, respectively). Almost all isolates (39/40, 97.5%) were multidrug resistant. The highest resistance rate was observed for ampicillin (100%), followed by erythromycin (95%) and levofloxacin (95%). Ampicillin resistance was associated with the presence of the blaA gene, encoding a class A ?-lactamase. The two rifampicin-resistant strains showed point mutations driving amino acid replacements in conserved residues of RNA polymerase subunit ? (RpoB). Tetracycline resistance was due to an efflux-mediated mechanism. Thirty-nine PFGE patterns were identified among the 40 C. urealyticum, indicating that they were not clonally related, but producing sporadic infections. These findings raise the need of maintaining surveillance strategies among this multidrug resistant pathogen.This research was funded by Plan Nacional de I+D+i 2013-2016 and Instituto de Salud Carlos III, Subdirección General de Redes y Centros de Investigación Cooperativa, Ministerio de Ciencia, Innovación y
Universidades, Spanish Network for Research in Infectious Diseases (REIPI) D16/0016/0007 and RD16/0016/0008), and co-financed by European Development Regional Fund “A way to achieve Europe”, Operative program Intelligent Growth 2014-2020
Micro-morphologies, habitats and associated biodiversity in a fluid venting submarine structure using ROV underwater images: Mercator mud volcano (Gulf of Cádiz)
Mercator mud volcano has been explored by direct visual observations using a ROV at 350 to 370 m depth. Underwater images, taken mainly at the summit, have allowed characterizing the fluid venting environment, where different microforms, habitats and associated biota, with typical seepage components have been identified. Chemosynthetic bacterial communities were detected and sampled at the northeastern side of the summit at 350 m, next to pockmark-like depressions with diameters ranging 1 to 3 m, bioturbation marks, sediment mounds and authigenic carbonates of different sizes (0.1-5m length). Chemosynthesis-based communities were mainly composed by bacterial mats (patch diameter 10-30 cm), however some remains of cold seep chemosymbiotic bivalves (Lucinoma asapheus) were also found on the sediment. Habitat types at Mercator MV are influenced by oceanographic and sedimentation processes deposition and favouring fauna colonizing diverse substrate types, such as large sponges on slabs and sea-pens and annelids on soft bottoms
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