Imitation and memory in language origins.
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Biomedical subjects
Publications and source records attributed to Ricardo García.
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INTRODUCTION: A national initiative on reduction of HIV mother-to-child-transmission is being implemented since 2003 in Colombia, including HIV counseled and voluntary testing as part of the routine antenatal care, comprehensive care with ARV treatment to HIV-positive pregnant women and their infected children, caesarian delivery, and replacement of breast milk. OBJECTIVE: To describe the achievements in the implementation of the prevention strategy of mother-to-child HIV transmission, 2003-2005. MATERIALS AND METHODS: The implementation procedures of the Project are described, as well as the coverage percentages achieved, the prevention of vertical transmission and its associated factors, and the six-month prevalence by geographical departments. The probability of transmission adjusted to the ARV treatment offered and the differences by regions are also analyzed. RESULTS: The Project was implemented in 757 municipalities (68%); diagnostic tests were performed to 200,853 pregnant women, 377 of whom were diagnosed as HIV positive (0.19%), with higher prevalences in the Caribbean region, and in the Departments of Quindio and Santander. Complete six-month follow-up after delivery was provided to 285 women and their neonates (12 of whom were HIV-positive). The probability of transmission with the use of ARV schemes during pregnancy (n=170) was 1.78% (IC 95%: 0.37-5.13%). Factors related to probability of transmission were: initial viral load > 10,000/mm3, absence of antenatal care, and late recruitment of pregnant women. No statistical differences were found between the ARV schemes used. In the Caribbean region, antenatal care was lower, and late recruitment of pregnant women was higher. CONCLUSIONS: Reduction of HIV mother-to-child-transmission is an effective preventive intervention, which also strengthens the quality of antenatal care services. Sustainability of this initiative, with nationwide coverage, must be a target for national and regional public health authorities, and for health care providers.
During the last few years great attention has been paid to the evaluation of the impact of extreme temperatures on human health. This paper examines the effect of extreme winter temperature on mortality in Madrid for people older than 65, using ARIMA and GAM models. Data correspond to 1,815 winter days over the period 1986-1997, during which time a total of 133,000 deaths occurred. The daily maximum temperature (T(max)) was shown to be the best thermal indicator of the impact of climate on mortality. When total mortality was considered, the maximum impact occurred 7-8 days after a temperature extreme; for circulatory diseases the lag was between 7 and 14 days. When respiratory causes were considered, two mortality peaks were evident at 4-5 and 11 days. When the impact of winter extreme temperatures was compared with that associated with summer extremes, it was found to occur over a longer term, and appeared to be more indirect.
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Although there is extensive literature about the effects of stimulants on sustained attention tasks in attentional deficit/hyperactivity disorder (ADHD), little is known about the effect of these drugs on other attentional tasks involving different neural systems. In this study we measured the effect of stimulants on ADHD children, both in the electroencephalographic (EEG) activity during sustained attentional tasks and in psychometric performance during selective attentional tasks. These tasks are known to rely on different cortical networks. Our results in children medicated with 10 mg of d-amphetamine administered 60 min before the study indicate (i) a significant increase in amplitude but not latency of the P300 component of the event-related potential (ERP) during the sustained attentional task and (ii) a significant improvement in the reaction times and correct responses in the selective attentional task. In addition to supporting the use of stimulants in children with attentional deficit/hyperactivity disorder, these results show a multifocal activity improvement of cortical structures linked to dopamine, and interestingly, to attention. All these analyses are framed in a wider study of diverse attentional functions in this syndrome.
A method to form and manipulate the properties of nanometer-size liquid bridges by an external electric field is discussed. The properties of bridges are shown to be the result of an interplay among the field-induced polarization of the water layer adsorbed on the surface, the surface energy, and the water condensation from the humid air. For a given tip-sample separation, a simple model predicts the existence of a threshold voltage V(th) to form the bridge in full agreement with experiments.
Six tropane alkaloid esters were isolated from the stems of Erythroxylum rotundifolium. The structures of three new tropane esters, 7beta-hydroxy-6beta-(3,4,5-trimethoxybenzoyloxy)-3alpha-(E)-(3,4,5-trimethoxycinnamoyloxy)tropane (1), 6beta-benzoyloxy-3alpha-(Z)-(3,4,5-trimethoxycinnamoyloxy)tropane (2), and (-)-6beta-benzoyloxy-3alpha-hydroxytropane (3), were established by spectroscopic techniques. When alkaloids 1-6 were evaluated against a panel of human cancer cell lines, the new compound 6beta-benzoyloxy-3alpha-(Z)-(3,4,5-trimethoxycinnamoyloxy)tropane (2) and three known compounds, 6beta-benzoyloxy-3alpha-(3,4,5-trimethoxycinnamoyloxy)tropane (4), 6beta-benzoyloxy-3alpha-(E)-(3,4,5-trimethoxycinnamoyloxy)tropane-7beta-ol (5), and 7beta-acetoxy-6beta-benzoyloxy-3alpha-(E)-(3,4,5-trimethoxycinnamoyloxy)tropane (6), demonstrated greatest activity with multidrug-resistant oral epidermoid carcinoma (KB-V1) cells incubated in the presence of vinblastine. Thus, tropane esters of this type can reverse the multidrug-resistance phenotype, presumably by interacting with P-glycoprotein.