Lemmel, Frédéric; ter Haar, Jörg; van der Biezen, John; Duvet, Ludovic; Nelms, Nick; Blommaert, Sander; Butler, Bart; van der Luijt, Cornelis; Heijnen, Jerko; Smit, Hans; Visser, Ivo
For future near infrared astronomy missions, ESA is developing a complete detection and conversion chain (photon to SpaceWire chain system): Large Format Array (aLFA-N) based on MCT type detectors. aLFA-C (Astronomy Large Format Array Controller): a versatile cryogenic detector controller. An aLFA-C prototype was developed by Caeleste (Belgium) under ESA contract (400106260400). To validate independently the performances of the aLFA-C prototype and consolidate the definition of the follow-on activity, a dedicated test bench has been designed and developed in ESTEC/ESA within the Payload Technology Validation group. This paper presents the test setup and the performance validation of the first prototype of this controller at room and cryogenic temperature. Test setup and software needed to test the HAWAII-2RG and aLFA-N detectors with the aLFA-C prototype at cryogenic temperature will be also presented.
Llebot, Clara; Rueda, Francisco J.; Solé, Jordi; Artigas, Mireia Lara; Estrada, Marta
A conceptual model of the physical behavior of a shallow (6 m deep) micro-tidal estuary (Alfacs Bay) is proposed, based on the interpretation of a field data set, and subsequently tested against the results of three-dimensional hydrodynamic simulations. At seasonal timescales, the buoyancy associated with freshwater inflows dominates the tidal forcing, yielding a strongly stratified two-layered system, with the surface and the bottom layers flowing in opposite directions (classical estuarine circulation). Wind controls the physical behavior of the bay at shorter (days to weeks) timescales. Three scenarios or states have been defined, depending on the strength of stratification relative to the predominant direction and magnitude of the wind forcing, parameterized through the Wedderburn number, W. For weak winds (scenario 1), with W ≫ 1, mixing occurs as a consequence of stirring and convective cooling, and the mixed layer deepens slowly. For strong winds, with W ≪ 1/2, mixing is fast and is largely driven by shear at the pycnocline. Two scenarios are further identified for W ≪ 1/2 depending on the directionality of the winds: one for persistent NW winds (scenario 2) and another for diurnal SW winds (scenario 3). In scenario 2, the water is pushed laterally, overturning the stratification and generating transverse density gradients. In scenario 3, the estuarine circulation is weakened and even reversed, yielding strong longitudinal density gradients. The bay waters relax quickly (within 10-18 h) back to the original state, after the wind ceases, as a result of the horizontal density gradients developed under wind forcing. Bay-sea exchange rates are shown to decrease significantly in the low W scenarios, the magnitudes of these changes being largely dependent on wind direction. These scenarios have important implications for the ecology of the bay, including the occurrence of phenomena such as harmful algal blooms.
Carrasco, N; López-Flores, I; Alcaraz, M; Furones, M D; Berthe, F C J; Arzul, I
Since the first description of Marteilia refringens (Paramyxea) in flat oysters Ostrea edulis in 1968 in the Aber Wrach, Brittany (France), the life-cycle of this parasite has remained unknown. However, recent studies, conducted in the 'claire' system, have proposed the planktonic copepod Acartia grani as a potential intermediate host for the parasite. Nevertheless, experimental transmission of the parasite through the copepod has failed. Recent studies in this field have reported the presence of the parasite in zooplankton from the bays of the Delta de l'Ebre, a more complex and natural estuarine environment than that of the claire. As a result, 2 new Marteilia host species were proposed: the copepods Oithona sp. (Cyclopoida) and an indeterminate Harpaticoida. Consequently, the objective of the present work was to study the dynamics of Marteilia in the zooplankton community from one of the bays, Alfacs Bay, as well as the dynamics of the parasite in cultivated mussels during 1 complete year. Six different zooplankton taxa appeared to be parasitized by M. refringens, including copepods (3 Calanoida, Acartia discaudata, A. clausi and A. italica; 1 Cyclopoida, Oithona sp.; and 1 Harpacticoida, Euterpina acutifrons), and larval stages of decapod crustaceans (zoea larvae of Brachyura, probably Portumnus sp.). These taxa are thus proposed as new subjects for study, since they could be intermediate hosts in the infection process of mussels by Marteilia.
This study investigated the effects of green tea polyphenols (GTP) and alfacalcidol on bone microstructure and strength along with possible mechanisms in rats with chronic inflammation. A 12-week study using a 2 (no GTP vs. 0.5%, w/v GTP in drinking water) × 2 (no alfacalcidol vs. 0.05 ug/kg alfacal...
Fernández-Tejedor, Margarita; Soubrier-Pedreño, M Angeles; Furones, M Dolores
Between January and April 2000, several experiments were performed during a Karlodinium spp. proliferation in Alfacs Bay (Ebro delta, NW Mediterranean) to determine the effects of these dinoflagellates on sea bream Sparus aurata cultivated in the area. Moribund fish showed an increase in plasma osmolality together with a decrease in the haematocrit percentage compared to control fish. The efficacy of copper sulphate, hydrogen peroxide, potassium permanganate and formalin against Karlodinium spp. was also tested. None of these treatments had mitigation effects when applied in the presence of fish; on the contrary, lethal effects appeared at lower Karlodinium spp. densities compared to fish control groups. When a lytic agent, such as copper sulphate, was used as a water pre-treatment, in the absence of fish, Karlodinium spp. toxicity was significantly reduced. Protocols for water pre-treatments were studied as a potential tool for combating Karlodinium spp. in fish farms.
Terra, Ricardo Mingarini; Andrade, Juliano Ribeiro; Mariani, Alessandro Wasum; Garcia, Rodrigo Gobbo; Succi, Jose Ernesto; Soares, Andrey; Zimmer, Paulo Marcelo
The concept of a hybrid operating room represents the union of a high-complexity surgical apparatus with state-of-the-art radiological tools (ultrasound, CT, fluoroscopy, or magnetic resonance imaging), in order to perform highly effective, minimally invasive procedures. Although the use of a hybrid operating room is well established in specialties such as neurosurgery and cardiovascular surgery, it has rarely been explored in thoracic surgery. Our objective was to discuss the possible applications of this technology in thoracic surgery, through the reporting of three cases. RESUMO O conceito de sala híbrida traduz a união de um aparato cirúrgico de alta complexidade com recursos radiológicos de última geração (ultrassom, TC, radioscopia e/ou ressonância magnética), visando a realização de procedimentos minimamente invasivos e altamente eficazes. Apesar de bem estabelecido em outras especialidades, como neurocirurgia e cirurgia cardiovascular, o uso da sala hibrida ainda é pouco explorado na cirurgia torácica. Nosso objetivo foi discutir as aplicações e as possibilidades abertas por essa tecnologia na cirurgia torácica através do relato de três casos.
Cerralbo, Pablo; Grifoll, Manel; Espino, Manuel
The Ebro Delta (NW Mediterranean Sea) is characterized by the presence of two semi-enclosed bays: Alfacs and Fangar. Both bays receive direct freshwater input from drain channels of rice fields. Southern Bay, Alfacs, is about 14km long by 4km wide with an average depth of about 3.1 m (maximum of 6.5 m in the middle). The mouth is about 2.5 km wide. The non-tidal flow in the area has been studied in the past, showing a persistent structure during most of the year: a salty layer in the bottom and freshwater layer on top due to freshwater input. The bay is micro-tidal, with a mixed tidal regime. An extensive field campaign was designed in order to characterize the hydrodynamic and T/S patterns during summer. First CTD transects were conducted during June 2012 and July 2013. Moreover, the positions of lagrangian drifters were tracked recording trajectories at sub-surface waters. Finally, two moored stations (within the Bay and Mouth) allowed to obtain hydrodynamic and T/S conditions during two-month period in summer 2013. Atmospheric data were obtained from three fixed land stations. Data analysis showed density differences from surface to bottom in the middle of the bay around 3-5 kg/m3 and almost constant over all the period. The density profiles seems to be controlled mainly from freshwater contributions (differences of 1.5 in salinity), although heat fluxes in summer contributes positively to the column stabilization (maximum vertical temperature differences of 5-6ºC). Observed well-mixed conditions were related with energetic wind events (northerly winds). The variability on water circulation is dominated by seiches (3h and 1h), with a clear barotropic mode and maximum intensities of 50 cm·s-1. These variability is modulated by diurnal winds (sea breeze regimes). On the other hand, low frequency motion is controlled by baroclinic estuarine circulation.
Rodellas, Valentí; Garcia-Orellana, Jordi; Trezzi, Giada; Masqué, Pere; Stieglitz, Thomas C.; Bokuniewicz, Henry; Cochran, J. Kirk; Berdalet, Elisa
The specific ingrowth rates of different radium isotopes make them valuable tracers to distinguish processes occurring at different temporal scales. Here we demonstrate the use of the radium quartet (223Ra, 224Ra, 226Ra and 228Ra) to differentiate flows of submarine groundwater discharge and porewater exchange to a coastal embayment (Alfacs Bay, NW Mediterranean Sea), based on the assumption that these processes occur on different time scales. In order to evaluate the seasonal dynamics of groundwater and porewater inputs to the bay, we conducted three seasonal samplings at Alfacs Bay, during which samples for Ra isotopes were collected from bay waters, groundwater springs, porewaters and irrigation channels. Activities of short-lived Ra isotopes in the bay showed a strong seasonality, (e.g. average 224Ra activities in summer (∼32 dpm 100 L-1) up to 4 times higher than in winter (∼8 dpm 100 L-1)). In contrast, the activities of the long-lived Ra isotopes were fairly constant throughout the year (e.g. activities of 226Ra were ∼16 and ∼14 dpm 100 L-1 in summer and winter, respectively). The relatively short exposure to sediments of recirculation fluxes resulted in porewaters significantly enriched in short-lived Ra isotopes relative to the long-lived ones (e.g. 224Ra = 1100-1300 dpm 100 L-1; 226Ra = 17-99 dpm 100 L-1), whereas coastal groundwaters were enriched in all the Ra isotopes (e.g. 224Ra = 120-150 dpm 100 L-1; 226Ra = 200-400 dpm 100 L-1). The distinct signatures of different sources allowed us to construct seasonal Ra mass balances to estimate both groundwater discharge, which ranges from (40 ± 60)·103 m3·d-1 in summer to (310 ± 200)·103 m3·d-1 in winter, and porewater exchange fluxes, ranging from (1200 ± 120)·103 m3·d-1 in summer to (270 ± 40)·103 m3·d-1 in winter. Whereas the seasonal variability of groundwater inputs is likely governed by the terrestrial hydraulic gradient, a qualitative evaluation of the drivers of porewater exchange
Park, Ji-Soo; Tang, Yingjie; Davis, Robert; Nemanich, Robert
N- and Al-polar (0001) wurtzite AlN films were grown on C- and Si-polar 6H-SiC substrates, respectively. The polarity was confirmed by KOH chemical etching and atomic force microscopy (AFM) imaging. The surfaces were cleaned in situ by annealing to ˜1100^oC in a flux of ammonia, and X-ray photoemission spectroscopy (XPS) and UV photoemission spectroscopy (UPS) were employed to measure the electronic states at the surfaces. The results indicated a similar electron affinity for both surfaces which appears to approach a value of zero. Furthermore, it was determined that the Fermi energy (Ec-Ef) was 2.4 eV below the conduction band for N-face AlN and 3.0 eV for Al-face AlN. The 0.6eV difference in the Fermi energy indicates a difference in band bending near the surface which is discussed in terms of the built-in field induced by the polarization bound surface charges.
Mascaró, O.; Romero, J.; Pérez, M.
In temperate regions, climatic factors impose a general seasonal pattern on seagrass growth that can be observed in leaf growth rates and, in small species, also in shoot density. Large variations in shoot density suggest a strong temporal uncoupling between shoot recruitment and shoot mortality, and the dependence of each of these processes on different drivers. Here we examine seasonal patterns of recruitment and mortality in the seagrass Cymodocea nodosa, one of the species most sensitive to seasonal forcing in the Mediterranean. We sampled two local populations submitted to different nutrient availability in Alfacs Bay (NW Mediterranean) and determined recruitment and mortality rates, as well as other plant traits, on a monthly basis. Our results confirm the hypothesized uncoupling, with maximum mortality 2 months after maximum recruitment. Whereas timing of recruitment was associated with light availability, and was supported by carbohydrate remobilisation, mortality was related to high water temperatures and probably also to light limitation in late summer due to self-shading. In the high-nutrient population, algal overgrowth caused further light deprivation, with mortality rates higher than in the low-nutrient population. It is emphasised that the demographic balance of the studied populations was negative for most of the year, with the exception of August and September. Therefore, caution is necessary when overall population trends are inferred from single annual sampling events.
Margulis, L.; Navarrete, A.; Sole, M.
Inocula from organic-rich black muds immediately underlying intertidal laminated microbial mats dominated by Microcoleus chthonoplastes yielded large, variable diameter spirochetes. These unusual spirochetes, previously reported only from the Alfacs Peninsula at the delta of the Ebro river in northeast Spain, contain striking arrays of cytoplasmic granules packed into their protoplasmic cylinders. On several occasions, both in summer and winter, the huge spirochetes were recognized in samples from mats growing in the Sippewissett salt marsh at Woods Hole Massachusetts. They were also seen in similar samples from microbial mats at North Pond, Laguna Figueroa, Baja California Norte, Mexico. The identity of these spirochetes was confirmed by electron microscopy: number and disposition of flagella, composite structure, measurements of their distinctive cytoplasmic granules. The granules, larger, more conspicuous and present in addition to ribosomes, are hypothesized to contain ATPases. As culture conditions worsen, these spirochetes retract into membrane-bounded round bodies in which they form refractile inclusions. From morphology and behavior we conclude the North American spirochetes from both Atlantic and Pacific intertidal microbial mats are indistinguishable from those at the delta of the Ebro river. We conclude a cosmopolitan distribution for Spirosymplokos deltaeiberi.
Gonçalves-Araujo, Rafael; Wiegmann, Sonja; Torrecilla, Elena; Bardaji, Raul; Röttgers, Rüdiger; Bracher, Astrid; Piera, Jaume
The detection and prediction of changes in coastal ecosystems require a better understanding of the complex physical, chemical and biological interactions, which involves that observations should be performed continuously. For this reason, there is an increasing demand for small, simple and cost-effective in situ sensors to analyze complex coastal waters at a broad range of scales. In this context, this study seeks to explore the potential of beam attenuation spectra, c(λ), measured in situ with an advanced-technology optical transmissometer, for assessing temporal and spatial patterns in the complex estuarine waters of Alfacs Bay (NW Mediterranean) as a test site. In particular, the information contained in the spectral beam attenuation coefficient was assessed and linked with different biogeochemical variables. The attenuation at λ = 710 nm was used as a proxy for particle concentration, TSM, whereas a novel parameter was adopted as an optical indicator for chlorophyll a (Chl-a) concentration, based on the local maximum of c(λ) observed at the long-wavelength side of the red band Chl-a absorption peak. In addition, since coloured dissolved organic matter (CDOM) has an important influence on the beam attenuation spectral shape and complementary measurements of particle size distribution were available, the beam attenuation spectral slope was used to analyze the CDOM content. Results were successfully compared with optical and biogeochemical variables from laboratory analysis of collocated water samples, and statistically significant correlations were found between the attenuation proxies and the biogeochemical variables TSM, Chl-a and CDOM. This outcome depicted the potential of high-frequency beam attenuation measurements as a simple, continuous and cost-effective approach for rapid detection of changes and patterns in biogeochemical properties in complex coastal environments. PMID:28107539
Macedo, Antonio Luiz de Vasconcellos; Schraibman, Vladimir
The intraoperative identification of certain anatomical structures because they are small or visually occult may be challenging. The development of minimally invasive surgery brought additional difficulties to identify these structures due to the lack of complete tactile sensitivity. A number of different forms of intraoperative mapping have been tried. Recently, the near-infrared fluorescence imaging technology with indocyanine green has been added to robotic platforms. In addition, this technology has been tested in several types of operations, and has advantages such as safety, low cost and good results. Disadvantages are linked to contrast distribution in certain clinical scenarios. The intraoperative near-infrared fluorescent imaging is new and promising addition to robotic surgery. Several reports show the utility of this technology in several different procedures. The ideal dose, time and site for dye injection are not well defined. No high quality evidence-based comparative studies and long-term follow-up outcomes have been published so far. Initial results, however, are good and safe. RESUMO A identificação intraoperatória de certas estruturas anatômicas, por seu tamanho ou por elas serem ocultas à visão, pode ser desafiadora. O desenvolvimento da cirurgia minimamente invasiva trouxe dificuldades adicionais, pela falta da sensibilidade tátil completa. Diversas formas de detecção intraoperatória destas estruturas têm sido tentadas. Recentemente, a tecnologia de fluorescência infravermelha com verde de indocianina foi associada às plataformas robóticas. Além disso, essa tecnologia tem sido testada em uma variedade de cirurgias, e suas vantagens parecem estar ligadas a baixo custo, segurança e bons resultados. As desvantagens estão associadas à má distribuição do contraste em determinados cenários. A imagem intraoperatória por fluorescência infravermelha é uma nova e promissora adição à cirurgia robótica. Diversas séries mostram
Busch, Julia A.; Price, Ivan; Jeansou, Eric; Zielinski, Oliver; van der Woerd, Hendrik J.
Ocean colour measurements from space are well suited to assess phytoplankton dynamics over broad spatial scales. Closer to the coast however, the quality of these data degrades as a result of the loading of sediments and dissolved matter from terrestrial runoff, the influences of land reflection on atmospheric correction and sea-bottom reflection, which compromise their use in coastal management actions. Recently, the enabling of citizens to provide environmental observations has gained recognition as a way for enhancing the spatio-temporal coverage of satellite observations. In the FP7 funded EU project "Citclops" (Citizens' observatory for coast and ocean optical monitoring), a smart phone app for the classification of water colour, simplified to 21 hues of the Forel Ule (FU) scale, is developed. In this study we examine two bays in the Ebro Delta (NW Mediterranean) where satellite data, hyperspectral measurements, and observations with the citizen tool for colour comparison were available. FU values and their corresponding novel colorimetric parameter, the hue colour angle, were derived in the bay at 12 stations with the traditional FU scale and one automated in-situ radiometric system at the Alfacs Bay aquaculture site. Both methods complied well during the study course of May-June 2011. These measurements were further compared to data from Full Resolution MERIS (Medium Resolution Imaging Spectrometer) satellite images. The quality of the retrieved hue angle varies over the image. For high-quality sites, MERIS hue colour angles and FU values gave a good estimate of seasonal algal dynamics in the bays over the year 2011, while ground measurements revealed colour changes over short space- and time frames, which are indicative of the fast dynamics of phytoplankton in the area that could not be fully resolved with MERIS data. The use of FU values and hue colour angle of water will allow a simple integration of data from hyperspectral measurements, MERIS