4,950 research outputs found

    Analysis of delays and cost overruns of road construction projects in the Colombian Caribbean Region

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    Construction projects are constantly threatened by delays and cost overruns that might compromise their viability. Th us, identifying the leading causes of these issues based on the experience of experienced professionals is essential to planning and reducing these risks. Th is research evaluates the frequency and severity of variables causing delays and cost overruns in Colombian Caribbean Region road projects. Th e nine causes studied in this research were defined through a literature review, preliminary discussion and a pilot test. A survey directed to 42 road construction engineers allowed the authors to characterise these professionals’ perceptions regarding the frequency and severity of these variables in terms of delay and cost overruns, with a confidence level of 80%. Statistical analyses were applied to the results of the survey to establish which variables generate the most significant impacts when building roads and related works in the Colombian Caribbean Region.Revisión por pare

    Relación de la mejora de la calidad de vida de los sujetos que practican actividad física con daño cerebral adquirido

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    RELACIÓN DE LA MEJORA DE LA CALIDAD DE VIDA DE LOS SUJETOS QUE PRACTICAN ACTIVIDAD FÍSICA CON DEÑO CEREBRAL ADQUIRID

    Relación entre las pruebas de funcionalidad de la marcha en personas con daño cerebral adquirido en fase subaguda

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    Objetivo: Analizar el grado de relación entre cuatro pruebas que valoran la funcionalidad de la marcha en sujetos jóvenes con daño cerebral adquirido (DCA) en fase subaguda y conocer el grado de relación entre estas pruebas y la percepción subjetiva de seguridad en actividades de la vida diaria. Metodología: 67 participantes jóvenes con DCA en fase subaguda (43 hombres y 24 mujeres) con una edad media 35,09 años. Se realizó estadística descriptiva de todas las variables demográficas: género, edad, IMC, meses desde que se produjo la lesión y etiología lesional. Para analizar si existe correlación entre las variables se utilizó el coeficiente de Pearson. Resultados: El Timed 10-Meter Walk presenta una correlación muy alta con Timed Up and Go (TUG) (r=093), alta con el 6-Minute Walk Test (r=0,77) y moderada con el Step Test (r=0,56). El 6-Minute Walk Test presenta una correlación alta con el TUG (r=0,82) y una correlación moderada con el Step Test (r=0,69). El Step Test presenta una correlación moderada con el TUG (r= -0,68). The Activities-specific Balance Confidence Scale (ABC) presenta una correlación moderada con el Timed 10-Meter Walk (r=0,42), TUG (R=0,40), 6-Minute Walk Test (r=0,40) y Step Test (r=0,44). Conclusiones: Las pruebas de funcionalidad de la marcha presentan una correlación significativa entre moderada y muy alta en personas jóvenes con DCA. El ABC presenta una correlación significativa moderada con las cuatro variables de funcionalidad de la marcha analizadas en esta població

    Prediction of depression in European general practice attendees: the PREDICT study

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    Background Prevention of depression must address multiple risk factors. Estimating overall risk across a range of putative risk factors is fundamental to prevention of depression. However, we lack reliable and valid methods of risk estimation. This protocol paper introduces PREDICT, an international research study to address this risk estimation. Methods/design This is a prospective study in which consecutive general practice attendees in six European countries are recruited and followed up after six and 12 months. Prevalence of depression is assessed at baseline and each follow-up point. Consecutive attendees between April 2003 and September 2004 who were aged 18 to 75 were asked to take part. The possibility of a depressive episode was assessed using the Depression Section of the Composite International Diagnostic Interview. A selection of presumed risk factors was based on our previous work and a systematic review of the literature. It was necessary to evaluate the test-retest reliability of a number of risk factor questions that were developed specifically, or adapted, for the PREDICT study. In a separate reliability study conducted between January and November 2003, consecutive general practice attendees in the six participating European countries completed the risk factor items on two occasions, two weeks apart. The overall response rate at entry to the study was 69%. We exceeded our expected recruitment rate, achieving a total of 10,048 people in all. Reliability coefficients were generally good to excellent. Discussion Response rate to follow-up in all countries was uniformly high, which suggests that prediction will be based on almost a full cohort. The results of our reliability analysis are encouraging and suggest that data collected during the course of PREDICT will have a satisfactory level of stability. The development of a multi-factor risk score for depression will lay the foundation for future research on risk reduction in primary care. Our data will also provide the necessary evidence base on which to develop and evaluate interventions to reduce the prevalence of depression

    Characterization of indicator tree species in neotropical environments and implications for geological mapping

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    FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOGeobotanical remote sensing (GbRS) in the strict sense is an indirect approach to obtain geological information in heavily vegetated areas for mineral prospecting and geological mapping. Using ultra- and hyperspectral technologies, the goals of this resea216385400FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO2010/51758-2, 2010/51718-0309712/2017-3, 302925/2015-

    Effect of an extract of Centella asiatica on the biodistribution of sodium pertechnetate (Na<sup>99m</sup>TcO<sub>4</sub>) and on the fixation of radioactivity on blood constituents

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    This study evaluates the effects of an acute treatment with a Centella asiatica (CA) extract on the biodistribution of the radiopharmaceutical Na99mTcO4 and on the fixation of technetium-99m on blood constituents. Wistar rats were treated with CA extract and, 1 hour after, Na99mTcO4 was administered; organs/tissues were withdrawn and weighted. The radioactivity was counted to calculate the percentage of activity per gram (%ATI/g). Also, blood samples were withdrawn, plasma (P), blood cells (BC), insoluble fraction (IF) and soluble fractions of P and BC were isolated and the radioactivity was counted to calculate the percentage of activity (%ATI). Data indicated that the acute treatment with CA extract changed significantly (p99mTcO4 and the fixation of the technetium-99m on blood constituents in an acute treatment

    trans-Bis(4,7-diphenyl-1,10-phenanthroline-κ2 N,N′)bis­(nitrato-κ2 O,O′)zinc(II)

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    The title compound, [Zn(NO3)2(C24H16N2)2], is a twofold axially symmetric coordination compound. Given that the Zn—O interactions [2.4926 (15) and 2.6673 (15) Å] can be considered as weakly bonding and the nitrate ions share the same C 2 axis of the Zn(dpp)2 fragment (dpp is 4,7-diphenyl-1,10-phenanthroline), these anions belong to the coordination sphere of Zn2+, leading to a complex with an overall coordination number of 8 for the metal ion

    Cognitive impairment induced by delta9-tetrahydrocannabinol occurs through heteromers between cannabinoid CB1 and serotonin 5-HT2A receptors

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    Delta-9-tetrahydrocannabinol (THC), the main psychoactive compound of marijuana, induces numerous undesirable effects, including memory impairments, anxiety, and dependence. Conversely, THC also has potentially therapeutic effects, including analgesia, muscle relaxation, and neuroprotection. However, the mechanisms that dissociate these responses are still not known. Using mice lacking the serotonin receptor 5-HT2A, we revealed that the analgesic and amnesic effects of THC are independent of each other: while amnesia induced by THC disappears in the mutant mice, THC can still promote analgesia in these animals. In subsequent molecular studies, we showed that in specific brain regions involved in memory formation, the receptors for THC and the 5-HT2A receptors work together by physically interacting with each other. Experimentally interfering with this interaction prevented the memory deficits induced by THC, but not its analgesic properties. Our results highlight a novel mechanism by which the beneficial analgesic properties of THC can be dissociated from its cognitive side effects

    Metastable liquid lamellar structures in binary and ternary mixtures of Lennard-Jones fluids

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    We have carried out extensive equilibrium molecular dynamics (MD) simulations to investigate the Liquid-Vapor coexistence in partially miscible binary and ternary mixtures of Lennard-Jones (LJ) fluids. We have studied in detail the time evolution of the density profiles and the interfacial properties in a temperature region of the phase diagram where the condensed phase is demixed. The composition of the mixtures are fixed, 50% for the binary mixture and 33.33% for the ternary mixture. The results of the simulations clearly indicate that in the range of temperatures 78<T<102o78 < T < 102 ^{\rm o}K, --in the scale of argon-- the system evolves towards a metastable alternated liquid-liquid lamellar state in coexistence with its vapor phase. These states can be achieved if the initial configuration is fully disordered, that is, when the particles of the fluids are randomly placed on the sites of an FCC crystal or the system is completely mixed. As temperature decreases these states become very well defined and more stables in time. We find that below 90o90 ^{\rm o}K, the alternated liquid-liquid lamellar state remains alive for 80 ns, in the scale of argon, the longest simulation we have carried out. Nonetheless, we believe that in this temperature region these states will be alive for even much longer times.Comment: 18 Latex-RevTex pages including 12 encapsulated postscript figures. Figures with better resolution available upon request. Accepted for publication in Phys. Rev. E Dec. 1st issu
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