1,138 research outputs found
Dimensão e causas da pobreza urbana
Dentro de uma perspectiva histórica, o desempenho recente dos países em desenvolvimento, no que se refere a indicadores globais de crescimento econômico, tem sido notável
Distribution of lipid biomarkers and carbon isotope fractionation in contrasting trophic environments of the South East Pacific
The distribution of lipid biomarkers and their stable carbon isotope composition was investigated on suspended particles from different contrasting trophic environments at six sites in the South East Pacific. High algal biomass with diatom-related lipids (24-methylcholesta-5,24(28)-dien-3&beta;-ol, C<sub>25</sub> HBI alkenes, C<sub>16:4</sub> FA, C<sub>20:5</sub> FA) was characteristic in the upwelling zone, whereas haptophyte lipids (long-chain (C<sub>37</sub>-C<sub>39</sub>) unsaturated ketones) were proportionally most abundant in the nutrient-poor settings of the centre of the South Pacific Gyre and on its easter edge. The dinoflagellate–sterol, 4&alpha;-23,24-trimethylcholest-22(<i>E</i>)-en-3&beta;-ol, was a minor contributor in all of the studied area and the cyanobacteria-hydrocarbon, C<sub>17</sub><i>n</i>-alkane, was at maximum in the high nutrient low chlorophyll regime of the subequatorial waters near the Marquesas archipelago. <br><br> The taxonomic and spatial variability of the relationships between carbon photosynthetic fractionation and environmental conditions for four specific algal taxa (diatoms, haptophytes, dinoflagellates and cyanobacteria) was also investigated. The carbon isotope fractionation factor (&epsilon;<sub>p</sub>) of the 24-methylcholesta-5,24(28)-dien-3&beta;-ol diatom marker, varied over a range of 16% along the different trophic systems. In contrast, &epsilon;<sub>p</sub> of dinoflagellate, cyanobacteria and alkenone markers varied only by 7–10&permil;. The low fractionation factors and small variations between the different phytoplankton markers measured in the upwelling area likely reveals uniformly high specific growth rates within the four phytoplankton taxa, and/or that transport of inorganic carbon into phytoplankton cells may not only occur by diffusion but also by other carbon concentrating mechanisms (CCM). In contrast, in the oligotrophic zone, i.e. gyre and eastgyre, relatively high &epsilon;<sub>p</sub> values, especially for the diatom marker, indicate diffusive CO<sub>2</sub> uptake by the eukaryotic phytoplankton. At these nutrient-poor sites, the lower &epsilon;<sub>p</sub> values for haptophytes, dinoflagellates and cyanobacteria indicate higher growth rates or major differences on the carbon uptake mechanisms compared to diatoms
A discursive psychology analysis of emotional support for men with colorectal cancer
Recent research into both masculinity and health, and the provision of social support for people with cancer has focussed upon the variations that may underlie broad assumptions about masculine health behaviour. The research reported here pursues this interest in variation by addressing the discursive properties of talk about emotional support, by men with colorectal cancer - an understudied group in the social support and cancer literature. Semi-structured interviews were conducted with eight men with colorectal cancer, and the transcripts analysed using an intensive discursive psychology approach. From this analysis two contrasting approaches to this group of men’s framing of emotional support in the context of cancer are described. First, talk about cancer was positioned as incompatible with preferred masculine identities. Second, social contact that affirms personal relationships was given value, subject to constraints arising from discourses concerning appropriate emotional expression. These results are discussed with reference to both the extant research literature on masculinity and health, and their clinical implications, particularly the advice on social support given to older male cancer patients, their families and friends
Ecology and biogeochemistry of contrasting trophic environments in the South East Pacific by carbon isotope ratios on lipid biomarkers
International audienceThe distribution of lipid biomarkers and their carbon isotope composition was investigated on suspended particles from different contrasting trophic environments at six sites in the South East Pacific. High algal biomass with diatom-related lipids was characteristic in the upwelling zone, whereas haptophyte lipids were proportionally most abundant in the nutrient-poor settings of the centre of the South Pacific Gyre and on its easter edge. Dinoflagellate–sterols were minor contributors in all of the studied area and cyanobacteria-hydrocarbons were at maximum in the high nutrient low chlorophyll regime of the subequatorial waters at near the Marquesas archipelago. The taxonomic and spatial variability of the relationships between carbon photosynthetic fractionation and environmental conditions for four specific algal taxa (diatoms, haptophytes, dinoflagellates and cyanobacteria) was also investigated. The carbon isotope fractionation factor (ep) of the diatom marker varied over a range of 16‰ along the different trophic systems. In contrast, ep of dinoflagellate, cyanobacteria and alkenone markers varied only by 7–10‰. The low fractionation factors and small variations between the different phytoplankton markers measured in the upwelling area likely reveals uniformly high specific growth rates within the four phytoplankton taxa, and/or that transport of inorganic carbon into phytoplankton cells may not only occur by diffusion but by other carbon concentrating mechanisms (CCM). In contrast, in the oligotrophic zone, i.e. gyre and eastgyre, relatively high ep values, especially for the diatom marker, indicate diffusive CO2 uptake by the eukaryotic phytoplankton. At these nutrient-poor sites, the lowest ep values for haptophytes, dinoflagellates and cyanobacteria infer higher growth rates compared to diatoms
Pramipexole for the treatment of depressive symptoms in patients with Parkinson disease: a randomized, double blind, placebo controlled trial
Background: Depression is common in patients with Parkinson's disease, but evidence on the efficacy of antidepressants in this population is lacking. Because depression in patients with Parkinson's disease might be related to dopaminergic dysfunction, we aimed to assess the efficacy of the dopamine agonist pramipexole for treatment of depressive symptoms in patients with Parkinson's disease.
METHODS:
We did a 12-week randomised, double-blind, placebo-controlled (1:1 ratio) trial of pramipexole (0.125-1.0 mg three times per day) compared with placebo in patients with mild-to-moderate Parkinson's disease. Patients from 76 centres in 12 European countries and South Africa were included if they were on stable antiparkinsonian therapy without motor fluctuations and had depressive symptoms (15-item geriatric depression scale score > or =5 and unified Parkinson's disease rating scale [UPDRS] part 1 depression item score > or =2). Patients were randomly assigned by centre in blocks of four by use of a randomisation number generating system. Clinical monitors, the principal investigator, and patients were masked to treatment allocation. The primary endpoint was change in Beck depression inventory (BDI) score and all treated patients who had at least one post-baseline efficacy assessment were included in the primary analysis. We also did a pre-specified path analysis with regression models to assess the relation between BDI and UPDRS part 3 (motor score) changes. This trial is registered with ClinicalTrials.gov, number NCT00297778, and EudraCT, number 2005-003788-22.
FINDINGS:
Between March, 2006, and February, 2008, we enrolled 323 patients. Of 296 patients randomly assigned to pramipexole or placebo, 287 were included in the primary analysis: 139 in the pramipexole group and 148 in the placebo group. BDI scores decreased by an adjusted mean 5.9 (SE 0.5) points in the pramipexole group and 4.0 (0.5) points in the placebo group (difference 1.9, 95% CI 0.5-3.4; p=0.01, ANCOVA). The UPDRS motor score decreased by an adjusted mean 4.4 (0.6) points in the pramipexole group and 2.2 (0.5) points in the placebo group (difference 2.2, 95% CI 0.7-3.7; p=0.003, ANCOVA). Path analysis showed the direct effect of pramipexole on depressive symptoms accounted for 80% of total treatment effect (p=0.04). Adverse events were reported in 105 of 144 patients in the pramipexole group and 101 of 152 in the placebo group. Adverse events in the pramipexole group were consistent with the known safety profile of the drug.
INTERPRETATION:
Pramipexole improved depressive symptoms in patients with Parkinson's disease, mainly through a direct antidepressant effect. This effect should be considered in the clinical management of patients with Parkinson's disease
Fiabilidad de la tomografía computarizada sin contraste en el seguimiento de las endoprótesis de aneurisma de aorta abdominal
Introducción: El aneurisma de aorta abdominal constituye una patología bastante frecuente en nuestro medio, con una prevalencia de 4 a 7.9% en hombres y 0.7 a 1.3% en mujeres. Una de las opciones terapéuticas es la exclusión del aneurisma mediante prótesis endovasculares, que requieren un seguimiento de por vida mediante diferentes pruebas de imagen. Las principales complicaciones que se desarrollan a lo largo del tiempo son las endofugas, el crecimiento del saco aneurismático, la rotura o migración del dispositivo y la isquemia (bien de miembros inferiores, intestinal, lumbar o renal). La prueba que ofrece mayor rendimiento es la angiografía por tomografía computarizada (angioTC), cuyas principales desventajas son la radiación ionizante y el riesgo de nefropatía por contraste iodado. Existe escasa bibliografía sobre el seguimiento con tomografía computarizada (TC) sin contraste en la reparación endovascular de los aneurismas de aorta abdominal.Objetivo: Evaluar la fiabilidad de los datos aportados por la TC respecto al angioTC con contraste en el seguimiento y diagnóstico de complicaciones en las endoprótesis aórticas, e identificación de los factores de riesgo relacionados con endofugas o crecimiento del saco aneurismático.Métodos: Se realizó un estudio analítico y retrospectivo tipo casos consecutivos del seguimiento de los pacientes con implante de endoprótesis aórtica en el servicio de Angiología y Cirugía Vascular del Hospital Clínico Universitario Lozano Blesa en el periodo de 2018 a 2020. 49 pacientes cumplieron los criterios de inclusión. Se creó una base de datos desde la intervención hasta la última fecha de seguimiento, recopilando diferentes variables relacionadas con las características de la muestra, patología aórtica, datos de la intervención quirúrgica y seguimiento. Se realizó en primer lugar un estudio descriptivo de las variables, centrado en la evolución de la función renal en el seguimiento y las fases del último escáner realizado. Se realizó un análisis estadístico inferencial, centrado en las variables que se pudieran correlacionar con la aparición de endofugas o aumento del saco aneurismático.Resultados: Se observó un aumento de la creatinina en el seguimiento. Se correlacionó la permeabilidad de las arterias hipogástricas y mesentérica inferior, tratamiento anticoagulante, antiagregación con clopidogrel y doble antiagregación con la aparición de endofugas y menor regresión o crecimiento del saco. La muestra para el análisis comparativo de los resultados de la TC con y sin contraste fue insuficiente. Conclusiones: En nuestro estudio hemos apreciado un incremento lento y paulatino de la creatinina en el primer año tras la intervención. Se han identificado diversos factores de riesgo (permeabilidad de las arterias hipogástricas y mesentérica inferior, tratamiento anticoagulante, antiagregación con clopidogrel y doble antiagregación) para la aparición de endofugas y menor regresión o crecimiento del saco, por lo que estos pacientes podrían precisar un seguimiento más exhaustivo. Si bien es cierto que el TAC sin contraste permite valorar la integridad de la prótesis y el crecimiento del aneurisma, se necesitan estudios con tamaño muestral mayor para analizar la fiabilidad de la TC sin contraste en el seguimiento del EVAR.Palabras clave: aneurisma de aorta abdominal; EVAR; AngioTC; TC sin contraste; seguimiento. <br /
Signal Quality Enhancement of Directly- Modulated VCSELs Using a Micro-Ring Resonator Transfer Function
Quad 14Gbps L-Band VCSEL-based System for WDM Migration of 4-lanes 56 Gbps Optical Data Links
We report on migrating multiple-lane link into an L-band VCSEL-based WDM system. Experimental validation achieves successful transmission over 10 km of SMF at 4x14Gbps. Inter-channel crosstalk penalty is observed to be less than 0.5 dB and a transmission penalty around 1 dB. The power budget margin ranges within 6 dB and 7 dB
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