361 research outputs found

    Planetary Radio Interferometry and Doppler Experiment (PRIDE) Technique: a Test Case of the Mars Express Phobos Fly-by. 2. Doppler tracking: Formulation of observed and computed values, and noise budget

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    Context. Closed-loop Doppler data obtained by deep space tracking networks (e.g., NASA's DSN and ESA's Estrack) are routinely used for navigation and science applications. By "shadow tracking" the spacecraft signal, Earth-based radio telescopes involved in Planetary Radio Interferometry and Doppler Experiment (PRIDE) can provide open-loop Doppler tracking data when the dedicated deep space tracking facilities are operating in closed-loop mode only. Aims. We explain in detail the data processing pipeline, discuss the capabilities of the technique and its potential applications in planetary science. Methods. We provide the formulation of the observed and computed values of the Doppler data in PRIDE tracking of spacecraft, and demonstrate the quality of the results using as a test case an experiment with ESA's Mars Express spacecraft. Results. We find that the Doppler residuals and the corresponding noise budget of the open-loop Doppler detections obtained with the PRIDE stations are comparable to the closed-loop Doppler detections obtained with the dedicated deep space tracking facilities

    Emotional cues enhance the attentional effects on spatial and temporal resolution

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    In the present study, we demonstrated that the emotional significance of a spatial cue enhances the effect of covert attention on spatial and temporal resolution (i.e., our ability to discriminate small spatial details and fast temporal flicker). Our results indicated that fearful face cues, as compared with neutral face cues, enhanced the attentional benefits in spatial resolution but also enhanced the attentional deficits in temporal resolution. Furthermore, we observed that the overall magnitudes of individuals’ attentional effects correlated strongly with the magnitude of the emotion × attention interaction effect. Combined, these findings provide strong support for the idea that emotion enhances the strength of a cue’s attentional response

    Venus Express radio occultation observed by PRIDE

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    Context. Radio occultation is a technique used to study planetary atmospheres by means of the refraction and absorption of a spacecraft carrier signal through the atmosphere of the celestial body of interest, as detected from a ground station on Earth. This technique is usually employed by the deep space tracking and communication facilities (e.g., NASA's Deep Space Network (DSN), ESA's Estrack). Aims. We want to characterize the capabilities of the Planetary Radio Interferometry and Doppler Experiment (PRIDE) technique for radio occultation experiments, using radio telescopes equipped with Very Long Baseline Interferometry (VLBI) instrumentation. Methods. We conducted a test with ESA's Venus Express (VEX), to evaluate the performance of the PRIDE technique for this particular application. We explain in detail the data processing pipeline of radio occultation experiments with PRIDE, based on the collection of so-called open-loop Doppler data with VLBI stations, and perform an error propagation analysis of the technique. Results. With the VEX test case and the corresponding error analysis, we have demonstrated that the PRIDE setup and processing pipeline is suited for radio occultation experiments of planetary bodies. The noise budget of the open-loop Doppler data collected with PRIDE indicated that the uncertainties in the derived density and temperature profiles remain within the range of uncertainties reported in previous Venus' studies. Open-loop Doppler data can probe deeper layers of thick atmospheres, such as that of Venus, when compared to closed-loop Doppler data. Furthermore, PRIDE through the VLBI networks around the world, provides a wide coverage and range of large antenna dishes, that can be used for this type of experiments

    Seroepidemiology of Toxoplasma gondii in wild ruminants in Spain

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    Trabajo presentado a la: XII Reunión de Ungulados Silvestres Ibéricos (RUSI). Vila Real, Portugal. 1-2 octubre.Peer reviewe

    Heat Transfer and Thermal Energy Storage Enhancement by Foams and Nanoparticles

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    The use of innovative methods for the design of heating, cooling, and heat storage devices has been mainly oriented in the last decade toward the use of nanofluids, metal foams coupled with working fluids, or phase change materials (PCMs). A network of nine Italian universities achieved significant results and innovative ideas on these topics by developing a collaborative project in the last four years, where different approaches and investigation techniques were synergically employed. They evaluated the quantitative extent of the enhancement in the heat transfer and thermal performance of a heat exchanger or thermal energy storage system with the combined use of nanofluids, metal foams, and PCMs. The different facets of this broad research program are surveyed in this article. Special focus is given to the comparison between the mesoscopic to macroscopic modeling of heat transfer in metal foams and nanofluids, as well as to the experimental data collected and processed in the development of the research

    Estado cualitativo y cuantitativo óseo generalizado en la osteonecrosis de maxilares. Efecto de los bifosfonatos

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    Objetivo: La osteonecrosis de maxilares (ONM) es una enfermedad recientemente descrita cuya etiopatogenia es desconocida, aunque se ha atribuido, entre otras causas, al tratamiento prolongado con bifosfonatos. Sin embargo, mientras que la ONM es una patología localizada, la acción de los bifosfonatos es generalizada, es decir, afecta a todos los huesos. No hay estudios que muestren el estado óseo general de los pacientes con ONM. Con este trabajo hemos querido estudiar en pacientes afectos de ONM dicho estado general mediante medidas cuantitativas y estimaciones cualitativas del hueso por medio de la densidad mineral ósea (DMO) y el trabecular bone score (TBS) y los parámetros ultrasonográficos en el calcáneo (QUS), además de la presencia de otras enfermedades y la toma de fármacos (especialmente los bifosfonatos) en los pacientes con ONM que pudieran participar en su etiopatogenia. Material y método: Estudio observacional y transversal de casos y controles, realizado en 304 pacientes de ambos sexos, en los que el grupo de casos (grupo I) estaba formado por 24 pacientes que habían sufrido una ONM, mientras que el grupo control (grupo II) estaba formado por 280 pacientes que no presentaban ONM y que recibían bifosfonatos desde un mínimo de 5 años por causas diversas. A todos ellos se les realizó una densitometría ósea (DXA, Hologic 4500 Discovery®) en la columna lumbar y en la extremidad proximal del fémur. Además, se les realizó mediciones del TBS en la columna lumbar, así como de los parámetros ultrasonográficos en el calcáneo (Hologic, Sahara®) en el pie dominante (QUS). Resultados: Los pacientes afectos de ONM tenían una mayor comorbilidad que los controles, con una mayor prevalencia de las siguientes enfermedades: diabetes mellitus, cáncer, artritis reumatoide, hipertiroidismo, cardiopatía, arritmias, insuficiencia cardíaca e hipercolesterolemia. Por ello, el consumo de corticoides, (orales e inhalados), anticoagulantes, hipnóticos, bifosfonatos i.v. (zoledronato), y quimioterapia antineoplásica fue también mayor entre los pacientes afectos de ONM que los pacientes controles. Sin embargo, entre los pacientes con ONM el porcentaje que tomaba bifosfonatos orales fue menor. Los valores densitométricos (DMO medida en la columna lumbar L2‐L4, cuello femoral y total de cadera) fueron más elevados en los pacientes con ONM en comparación con los de los controles. El TBS no mostró diferencias estadísticamente significativas entre ambos grupos, y los ultrasonidos presentaron valores más elevados de QUI y SOS en los pacientes con ONM que en los controles. La prevalencia de fracturas por fragilidad fue similar en ambos grupos. Conclusiones: Nuestros pacientes afectos de ONM mostraron una mayor comorbilidad y un mayor consumo de fármacos que los pacientes del grupo control, a excepción de bifosfonatos orales. Por otro lado, tanto la DMO como los parámetros ultrasonográficos mostraron valores más elevados en los pacientes con ONM que los controles. Si consideramos la DXA como una técnica medidora de la cantidad de masa ósea, y el TBS y la ultrasonografía de calcáneo técnicas estimadoras de aspectos cualitativos del hueso, podemos suponer que ni la cantidad ni la calidad óseas en general parecen estar afectadas en la ONM, siendo probablemente otro su mecanismo etiopatogénico. Los bifosfonatos orales no parecen estar entre los fármacos que participen en la etiología de la ONM, aunque sí los bifosfonatos más potentes que se administran por vía intravenosa, si bien no pueden considerarse independientemente de la patología subyacente para la cual se administran

    Seropositivity and Risk Factors Associated with Toxoplasma gondii Infection in Wild Birds from Spain

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    Toxoplasma gondii is a zoonotic intracellular protozoan parasite of worldwide distribution that infects many species of warm-blooded animals, including birds. To date, there is scant information about the seropositivity of T. gondii and the risk factors associated with T. gondii infection in wild bird populations. In the present study, T. gondii infection was evaluated on sera obtained from 1079 wild birds belonging to 56 species (including Falconiformes (n = 610), Strigiformes (n = 260), Ciconiiformes (n = 156), Gruiformes (n = 21), and other orders (n = 32), from different areas of Spain. Antibodies to T. gondii (modified agglutination test, MAT titer ≥1∶25) were found in 282 (26.1%, IC95%:23.5–28.7) of the 1079 birds. This study constitute the first extensive survey in wild birds species in Spain and reports for the first time T. gondii antibodies in the griffon vulture (Gyps fulvus), short-toed snake-eagle (Circaetus gallicus), Bonelli's eagle (Aquila fasciata), golden eagle (Aquila chrysaetos), bearded vulture (Gypaetus barbatus), osprey (Pandion haliaetus), Montagu's harrier (Circus pygargus), Western marsh-harrier (Circus aeruginosus), peregrine falcon (Falco peregrinus), long-eared owl (Asio otus), common scops owl (Otus scops), Eurasian spoonbill (Platalea leucorodia), white stork (Ciconia ciconia), grey heron (Ardea cinerea), common moorhen (Gallinula chloropus); in the International Union for Conservation of Nature (IUCN) “vulnerable” Spanish imperial eagle (Aquila adalberti), lesser kestrel (Falco naumanni) and great bustard (Otis tarda); and in the IUCN “near threatened” red kite (Milvus milvus). The highest seropositivity by species was observed in the Eurasian eagle owl (Bubo bubo) (68.1%, 98 of 144). The main risk factors associated with T. gondii seropositivity in wild birds were age and diet, with the highest exposure in older animals and in carnivorous wild birds. The results showed that T. gondii infection is widespread and can be at a high level in many wild birds in Spain, most likely related to their feeding behaviour

    Factors associated with Toxoplasma gondii infection in confined farrow-to-finish pig herds in western France: an exploratory study in 60 herds

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    Background: Infection by Toxoplasma gondii postnatally can occur after ingestion of contaminated meat or water (tissue cysts/oocysts). In Europe, percentage of meat borne infections is estimated between 30 and 63 %, out of which pork makes the most important source. The aim of this study was to (i) investigate the seroprevalence of T. gondii in intensive pig farms from western France; and (ii) identify the risk factors associated with seropositivity. Methods: Data were collected between November 2006 and February 2008 in 60 intensive farrow-to-finish farms, where sera were taken from 3595 fattening pigs, weaned and suckling piglets. Information about three classes of potential seropositivity risk factors were obtained through a questionnaire concerning: (i) breeding characteristics; (ii) farm management; and (iii) husbandry and hygiene. The modified agglutination test (MAT) was used for detection of specific anti T. gondii antibodies in pig sera, starting from 1/6 dilution. Results: The overall proportion of seropositive animals was 6.9 %, but the proportion of herds with at least one positive pig was 100 %. Multivariate logistic mixed model showed an increased seropositivity risk in weaned compared to suckling piglets, and a decreasing risk for mid-sized and large farms. The presence of a Danish entry facility, that clearly separates clean and dirty areas, had a protective effect on T. gondii seropositivity as well. Conclusions: The observed proportion of herds with at least one T. gondii seropositive animal provides further evidence that even in confined conditions of pig breeding, infection occurs, and is common. The highest risk for acquiring T. gondii is at the end of weaning period. Smaller confined pig farms demonstrate higher T. gondii seropositivity levels. This study also showed that Danish entry on farm buildings provides effective protection against T. gondii

    Aldehyde Dehydrogenase 2 (ALDH2) in Rat Fatty Liver Cold Ischemia Injury

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    Institut George Lopez-1 (IGL-1) and Histidine-tryptophan-ketoglutarate (HTK) solutions are proposed as alternatives to UW (gold standard) in liver preservation. Their composition differs in terms of the presence/absence of oncotic agents such as HES or PEG, and is decisive for graft conservation before transplantation. This is especially so when fatty (steatotic) livers are used since these grafts are more vulnerable to ischemia insult during conservation. Their composition determines the extent of the subsequent reperfusion injury after transplantation. Aldehyde dehydrogenase-2 (ALDH2), a mitochondrial enzyme, has been reported to play a protective role in warm ischemia-reperfusion injury (IRI), but its potential in fatty liver cold ischemic injury has not yet been investigated. We evaluated the relevance of ALDH2 activity in cold ischemia injury when fatty liver grafts from Zucker Obese rats were preserved in UW, HTK, and IGL-1 solutions, in order to study the mechanisms involved. ALDH2 upregulation was highest in livers preserved in IGL-1. It was accompanied by a decrease in transaminases, apoptosis (Caspase 3 and TUNEL assay), and lipoperoxidation, which was concomitant with the effective clearance of toxic aldehydes such as 4-hydroxy-nonenal. Variations in ATP levels were also determined. The results were consistent with levels of NF-E2 p45-related factor 2 (Nrf2), an antioxidant factor. Here we report for the first time the relevance of mitochondrial ALDH2 in fatty liver cold preservation and suggest that ALDH2 could be considered a potential therapeutic target or regulator in clinical transplantation
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