1000 resultados para -0.3T


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L’objectiu d’aquest treball és proposar, estudiar i analitzar un conjunt de models d’aplicació de les TIC, i més concretament d’eines associades a la Web 2.0, en la docència presencial de la Facultat de Comunicació de la Universitat Pompeu Fabra.Partint d’aquest objectiu, les idees principals que s’aporten en aquest treballsón: la necessitat d’actualitzar el model docent presencial amb les eines d’Internet que estan a l’abast dels estudiants, per tal d’innovar i arribar a superar els estàndards europeus de qualitat docent. Per donar validesa a aquest treball, s’ha fet una revisió dels models teòrics associats a laSocietat del Coneixement, les Tecnologies de la Informació i la Comunicació, la Tecnologia Educativa, Internet i la Web 2.0, i el sistema d’ensenyament superior a la Universitat Pompeu Fabra.Aquest treball és una porta oberta cap a una tesi on s’ha establert el següent esquema de treball:· Revisió de la bibliografia precedent i adquisició del coneixement de nous conceptes i models teòrics.· Disseny d’un marc pràctic per tal d’obtenir diverses variables per a la posterior anàlisi.· Aplicació de la matèria a la Universitat Pompeu Fabra.

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To enhance the clinical value of coronary magnetic resonance angiography (MRA), high-relaxivity contrast agents have recently been used at 3T. Here we examine a uniform bilateral shadowing artifact observed along the coronary arteries in MRA images collected using such a contrast agent. Simulations were performed to characterize this artifact, including its origin, to determine how best to mitigate this effect, and to optimize a data acquisition/injection scheme. An intraluminal contrast agent concentration model was used to simulate various acquisition strategies with two profile orders for a slow-infusion of a high-relaxivity contrast agent. Filtering effects from temporally variable weighting in k-space are prominent when a centric, radial (CR) profile order is applied during contrast infusion, resulting in decreased signal enhancement and underestimation of vessel width, while both pre- and postinfusion steady-state acquisitions result in overestimation of the vessel width. Acquisition during the brief postinfusion steady-state produces the greatest signal enhancement and minimizes k-space filtering artifacts.

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PURPOSE: To improve fat saturation in coronary MRA at 3T by using a spectrally selective adiabatic T2 -Prep (WSA-T2 -Prep). METHODS: A conventional adiabatic T2 -Prep (CA-T2 -Prep) was modified, such that the excitation and restoration pulses were of differing bandwidths. On-resonance spins are T2 -Prepared, whereas off-resonance spins, such as fat, are spoiled. This approach was combined with a CHEmically Selective Saturation (CHESS) pulse to achieve even greater fat suppression. Numerical simulations were followed by phantom validation and in vivo coronary MRA. RESULTS: Numerical simulations demonstrated that augmenting a CHESS pulse with a WSA-T2 -Prep improved robustness to B1 inhomogeneities and that this combined fat suppression was effective over a broader spectral range than that of a CHESS pulse in a conventional T2 -Prepared sequence. Phantom studies also demonstrated that the WSA-T2 -Prep+CHESS combination produced greater fat suppression across a range of B1 values than did a CA-T2 -Prep+CHESS combination. Lastly, in vivo measurements demonstrated that the contrast-to-noise ratio between blood and myocardium was not adversely affected by using a WSA-T2 -Prep, despite the improved abdominal and epicardial fat suppression. Additionally, vessel sharpness improved. CONCLUSION: The proposed WSA-T2 -Prep method was shown to improve fat suppression and vessel sharpness as compared to a CA-T2 -Prep technique, and to also increase fat suppression when combined with a CHESS pulse.

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Abstract OBJECTIVE Determining which is the most effective solution (heparin flush compared to 0.9% saline flush) for reducing the risk of occlusions in central venous catheters (CVC) in adults. METHOD The systematic review followed the principles proposed by the Cochrane Handbook; critical analysis, extraction and synthesis of data were performed by two independent researchers; statistical analysis was performed using the RevMan program 5.2.8. RESULTS Eight randomized controlled trials and one cohort study were included and the results of the meta-analysis showed no difference (RR=0.68, 95% CI=0.41-1.10; p=0.12). Analysis by subgroups showed that there was no difference in fully deployed CVC (RR=1.09, CI 95%=0.53-2.22;p=0.82); Multi-Lumen CVC showed beneficial effects in the heparin group (RR=0.53, CI 95%=0.29-0.95; p=0.03); in Double-Lumen CVC for hemodialysis (RR=1.18, CI 95%=0.08-17.82;p=0.90) and Peripherally inserted CVC (RR=0.14, CI 95%=0.01-2.60; p=0.19) also showed no difference. CONCLUSION Saline solution is sufficient for maintaining patency of the central venous catheter, preventing the risks associated with heparin administration.

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El ciberperiodismo ha evolucionado, desde una etapa facsimilar, hasta su estado actual en el que aprovecha mejor los recursos de Internet y se diferencia del periodismo en soporte físico. El surgimiento de la Web 2.0 supone para los medios digitales y los estudiosos de la comunicación un aprendizaje y adaptación constantes. El acelerado cambio que ha caracterizado a estas nuevas tecnologías de la información ha causado que los cibermedios comenzaran a utilizarlas sin establecer estrategias ni objetivos previos; en su lugar, los han ido desarrollando y mejorando sobre la base de la experiencia, para así explotar al máximo el potencial que ofrecen. El presente estudio comprende una investigación descriptiva de tipo empírico y de carácter cuantitativo sobre el uso de estas plataformas que ejercen los medios deportivos on-line editados en Cataluña.

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Històricament la inserció de Colombia a les TIC i al desenvolupament que aquestes comporten va ser lenta. Tot i això, als últims anys s'han desenvolupat projectes de infraestructura i apropiació tecnològica a grans velocitats. En aquest escenari la educomunicació ha avançat de manera formidable i la web colombiana comença a nodrir-se de continguts abundants i de qualitat per a l'educació. Aquest treball examina les principals iniciatives 2.0 per a l'educomunicació i dóna un diagnòstic sobre la seva funcionalitat (progressos i carències). Finalment, dóna una serie de recomanacions per al correcte ús de les eines que ofereix la web 2.0

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A `next' operator, s, is built on the set R1=(0,1]-{ 1-1/e} defining a partial order that, with the help of the axiom of choice, can be extended to a total order in R1. Besides, the orbits {sn(a)}nare all dense in R1 and are constituted by elements of the samearithmetical character: if a is an algebraic irrational of degreek all the elements in a's orbit are algebraic of degree k; if a istranscendental, all are transcendental. Moreover, the asymptoticdistribution function of the sequence formed by the elements in anyof the half-orbits is a continuous, strictly increasing, singularfunction very similar to the well-known Minkowski's ?(×) function.

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No presente trabalho procuramos entender mais sobre o conceito da Web 2.0, pois apesar de esta fazer parte do quotidiano da nossa sociedade, são poucos que conhecem a sua evolução. A Web 2.0 trata-se de um espaço em que a interactividade é uma das peças chave. Essa característica introduz desenvolvimentos em conceitos como cidadania e democracia e marca um virar de página na comunicação e no marketing político. Esta monografia procura ainda, através de um estudo de caso, perceber de que forma é que os progressos introduzidos pela Web 2.0 são sentidos na forma como se opera a comunicação política em Cabo Verde.

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BACKGROUND: HIV-1 RNA viral load is a key parameter for reliable treatment monitoring of HIV-1 infection. Accurate HIV-1 RNA quantitation can be impaired by primer and probe sequence polymorphisms as a result of tremendous genetic diversity and ongoing evolution of HIV-1. A novel dual HIV-1 target amplification approach was realized in the quantitative COBAS AmpliPrep/COBAS TaqMan HIV-1 Test, v2.0 (HIV-1 TaqMan test v2.0) to cope with the high genetic diversity of the virus. OBJECTIVES AND STUDY DESIGN: The performance of the new assay was evaluated for sensitivity, dynamic range, precision, subtype inclusivity, diagnostic and analytical specificity, interfering substances, and correlation with the COBAS AmpliPrep/COBAS TaqMan HIV-1 (HIV-1 TaqMan test v1.0) predecessor test in patients specimens. RESULTS: The new assay demonstrated a sensitivity of 20 copies/mL, a linear measuring range of 20-10,000,000 copies/mL, with a lower limit of quantitation of 20 copies/mL. HIV-1 Group M subtypes and HIV-1 Group O were quantified within +/-0.3 log(10) of the assigned titers. Specificity was 100% in 660 tested specimens, no cross reactivity was found for 15 pathogens nor any interference for endogenous substances or 29 drugs. Good comparability with the predecessor assay was demonstrated in 82 positive patient samples. In selected clinical samples 35/66 specimens were found underquantitated in the predecessor assay; all were quantitated correctly in the new assay. CONCLUSIONS: The dual-target approach for the HIV-1 TaqMan test v2.0 enables superior HIV-1 Group M subtype coverage including HIV-1 Group O detection. Correct quantitation of specimens underquantitated in the HIV-1 TaqMan test v1.0 test was demonstrated.