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Search Results: 1 - 10 of 74917 matches for " David Gon?alves "
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Robust Network Reconstruction in Polynomial Time
David Hayden,Ye Yuan,Jorge Gonalves
Mathematics , 2012,
Abstract: This paper presents an efficient algorithm for robust network reconstruction of Linear Time-Invariant (LTI) systems in the presence of noise, estimation errors and unmodelled nonlinearities. The method here builds on previous work on robust reconstruction to provide a practical implementation with polynomial computational complexity. Following the same experimental protocol, the algorithm obtains a set of structurally-related candidate solutions spanning every level of sparsity. We prove the existence of a magnitude bound on the noise, which if satisfied, guarantees that one of these structures is the correct solution. A problem-specific model-selection procedure then selects a single solution from this set and provides a measure of confidence in that solution. Extensive simulations quantify the expected performance for different levels of noise and show that significantly more noise can be tolerated in comparison to the original method.
Learning Spanish dialects through Twitter
Bruno Gonalves,David Sánchez
Computer Science , 2015,
Abstract: We map the large-scale variation of the Spanish language by employing a corpus based on geographically tagged Twitter messages. Lexical dialects are extracted from an analysis of variants of tens of concepts. The resulting maps show linguistic variations on an unprecedented scale across the globe. We discuss the properties of the main dialects within a machine learning approach and find that varieties spoken in urban areas have an international character in contrast to country areas where dialects show a more regional uniformity.
Crowdsourcing Dialect Characterization through Twitter
Bruno Gonalves,David Sánchez
Computer Science , 2014, DOI: 10.1371/journal.pone.0112074
Abstract: We perform a large-scale analysis of language diatopic variation using geotagged microblogging datasets. By collecting all Twitter messages written in Spanish over more than two years, we build a corpus from which a carefully selected list of concepts allows us to characterize Spanish varieties on a global scale. A cluster analysis proves the existence of well defined macroregions sharing common lexical properties. Remarkably enough, we find that Spanish language is split into two superdialects, namely, an urban speech used across major American and Spanish citites and a diverse form that encompasses rural areas and small towns. The latter can be further clustered into smaller varieties with a stronger regional character.
A Proof-of-Concept Assessment of the Safety and Efficacy of Intralesional Diclofenac in the Treatment of Cutaneous Neurofibromas  [PDF]
Mauro Geller, Aguinaldo Bonalumi Filho, Lisa Oliveira, Allan E. Rubenstein, Luiz Guilherme Darrigo Jr., David Azulay, Allan Bernacchi, Marcia Gonalves Ribeiro, Karin Soares Gonalves Cunha
International Journal of Clinical Medicine (IJCM) , 2015, DOI: 10.4236/ijcm.2015.612128
Abstract: The objectives of this study were to assess the safety and efficacy of intralesionally administered diclofenac in the treatment of cutaneous neurofibromas in patients with NF1. This was a proof-of-concept, prospective, safety and efficacy study of the effect of intralesionally administered diclofenac 25 mg/ml given once a week to 3 target cutaneous neurofibromas for 4 consecutive weeks. Overall, there was no significant change in neurofibroma size. During the study, some treated lesions developed signs of necrosis and fell off after a few weeks, but none of the control neurofibromas fell off. There were no significant changes in patient’s vital signs. A few adverse events occurred, mostly at the injection sites. During the study, some neurofibromas developed necrosis after the diclofenac injections and eventually detached from the patient. Overall, diclofenac was well tolerated, suggesting minimal systemic exposure, which required confirmation and further studies, including bioavailability analysis.
Efeitos das condi??es climáticas no trimestre de nascimento sobre asma e pneumonia na infancia e na vida adulta em uma coorte no Sul do Brasil
González, David Alejandro;Victora, Cesar G.;Gonalves, Helen;
Cadernos de Saúde Pública , 2008, DOI: 10.1590/S0102-311X2008000500016
Abstract: this study evaluated the effects of seasonal weather at time of birth and ambient temperature during the first six months of life on hospitalizations due to asthma and pneumonia in preschool children and on diagnosis of asthma in adulthood among individuals from the 1982 birth cohort in pelotas, rio grande do sul, brazil. the cohort included 5,914 live births, of which 77% were followed up until adulthood (23-24 yr). the risk of hospitalization due to pneumonia and asthma among children born from april to june (autumn) was 1.31 (95%ci: 0.99-1.73) to 2.4 (95%ci: 1.11-4.99) times higher than that of children born from january to march (summer). for temperature in the first six months of life, risk of hospitalization was 1.64 (95%ci: 1.26-2.13) to 3.16 (95%ci: 1.63-6.12) times higher for children born in the coldest as compared to the hottest temperature tertile. the effects of seasonality decreased with age, and the association with asthma in adulthood was weak. hospitalizations in poor children were more frequent, but the effects of seasonality on pneumonia were more evident among the wealthiest.
Differential diagnosis in encephalic vascular malformation in a child: case report = Diagnóstico diferencial de malforma o vascular encefálica em uma crian a: relato de caso
Nordon, David Gonalves,Esposito, Sandro Blasi,Loureiro, Maria Carolina
Scientia Medica , 2011,
Abstract: Objetivos: relatar um caso de malforma o venosa encefálica, n o comumente descrito na literatura, apesar de sua importancia como um dos principais diagnósticos diferenciais em hemorragia intracraniana em crian as. Descri o do Caso: uma menina de cinco anos de idade apresentava cefaleia cr nica e teve o primeiro episódio de convuls o. Possíveis altera es intracranianas foram investigadas como fatores etiológicos, e foi identificada uma altera o na veia de Labbé, possivelmente associada a um cavernoma na regi o temporal esquerda, o que provocou a hemorragia. Conclus es: convuls es primárias e cefaleia s o relativamente comuns em crian as. No entanto, convuls es secundárias, tais como aquelas causadas por hemorragia, apesar de serem menos comuns, devem ser suspeitadas e investigadas, pois podem levar a complica es graves. Aims: To report a case of encephalic venous malformation, which is not commonly described in the literature, despite its importance as one of the main differential diagnosis in intracranial hemorrhage in children. Case Description: A five-year old girl presented chronic headache and had the first episode of seizure. Possible intracranial alterations were investigated as etiological factors, and an alteration in the Labbé vein was identified, possibly associated to a cavernoma in the left temporal region, which caused the hemorrhage. Conclusions: Primary seizures and headaches are relatively common in children. However, secondary seizures such as those caused by hemorrhage, despite being less common, must be suspected and investigated, as they may lead to severe complications.
Stress prevention by modulation of autonomic nervous system (heart rate variability): A preliminary study using transcranial direct current stimulation  [PDF]
Eduardo Manuel Gonalves
Open Journal of Psychiatry (OJPsych) , 2012, DOI: 10.4236/ojpsych.2012.22016
Abstract: Introduction: Transcranial Direct Current Stimulation (tDCS) is a non-invasive, technique for brain stimulation. Anodal stimulation causes neuronal depolarisation and long-term potentiation, while cathodal stimulation causes hyperpolarisation and long-term depression. Stressors are associated with an increase in sympathetic cardiac control, a decrease in parasympathetic control, or both. Associated with these reactions is a frequently reported increase in Low Frequency (LF) Heart Rate Variability (HRV), a decrease in High Frequency (HF) power, and/or an increase in the LF/HF ratio. Objectives and aims: The present work aims to explore the tDCS potential in the modulation of the Autonomic Nervous System (ANS), through indirect stimulation of Anterior Cingulate Cortex (ACC). Methods: Two subjects, a 39 year old female and a 49 year old male, gave informed consent. Saline soaked synthetic sponges involving two, thick, metalic (stainless steel) rectangles, with an area of 25 cm2 each have been used as electrodes, connected to Iomed Phoresor II Auto device. It has been delivered a 2 mA current, for 20 minutes, over the left Dorsolateral Prefrontal Cortex (DLPFC) (Anode). Spectrum analysis (cStress software) of HRV has been performed before and after tDCS administration. Results: The female/male subject results of LF power, HF power and LF/HF ratio, before tDCS administration, were, respectively: 50.1 nu/60 nu, 46.1 nu/21.7 nu and 1.087/2.771; and, after tDCS administration, respectively: 33.5 nu/52.7 nu, 47.6 nu/ 22.8 nu and 0.704/2.312. Conclusions: tDCS over the left DLPFC (left ACC) increased parasympathetic activity and decreased sympathetic activity, suggesting the importance of tDCS in the management of stress-related disorders.
Interleukin (IL)-4 Induces Leukocyte Infiltration In Vivo by an Indirect Mechanism
Claude Ratthé,Jamila Ennaciri,David M. Garcês Gon alves,Sonia Chiasson,Denis Girard
Mediators of Inflammation , 2009, DOI: 10.1155/2009/193970
Abstract: Interleukin (IL)-4 is a cytokine known mainly for its anti-inflammatory activity. Using the in vivo murine air pouch model, we found that IL-4 significantly increased the number of leukocytes after 9 hours of treatment, consisting mainly of neutrophil (60%) and monocytic (40%) cell populations. Using an antibody array, we found that the expression of several analytes (predominantly CCL2) was increased by IL-4 before the arrival of leukocytes. The IL-4-induced expression of CCL-2 was confirmed by ELISA. Air pouch resident lining cells were harvested and were found to express IL-4R. CCL2 mRNA expression was monitored in lining cells, cells isolated from the air pouch skin, in RAW264.7 macrophage and in epithelial Mode-K cells and its expression was increased in response to IL-4 in all conditions. We conclude that IL-4 can attract leukocytes in vivo by an indirect mechanism involving the production of several analytes by, at least, resident cells.
Africanized honey bees (Apis mellifera L.) are more efficient at removing worker brood artificially infested with the parasitic mite Varroa jacobsoni Oudemans than are Italian bees or Italian/Africanized hybrids
Guerra Jr., José Carlos Vieira;Gonalves, Lionel Segui;Jong, David De;
Genetics and Molecular Biology , 2000, DOI: 10.1590/S1415-47572000000100016
Abstract: africanized honey bees are more tolerant of infestations with the mite varroa jacobsoni than are honey bees of european origin. the capacity of these bees to detect and react to brood infested with this mite could be one of the factors determining this tolerance. we tested colonies of africanized bees headed by queens from swarms collected in ribeir?o preto, s?o paulo state. the italian colonies had queens imported directly from the usa, or from the brazilian island of fernando de noronha, where varroa-infested italian colonies have been maintained, untreated, since 1984. recently sealed worker brood cells were artificially infested by opening the cell capping, inserting live adult female mites and resealing the cells. control cells were treated in the same way, but without introducing mites. the ability of the africanized honey bees to recognize and remove this artificially infested brood was compared with that of first generation italian/africanized hybrid bees, and with the two groups of "pure" italian bees, in three separate experiments. africanized colonies removed a mean of 51% of the infested brood, while italian/africanized hybrid colonies removed 25%. africanized colonies also removed a significantly greater proportion of infested brood than did italian colonies, headed by queens from the usa (59 vs. 31%, respectively). similarly, when africanized colonies were compared with colonies of italian bees from fernando de noronha, the former were found to be significantly more efficient at removing infested brood (61 vs. 35%, respectively), even though the population of italian bees on this island has been exposed to and survived varroa infestations (without treatment) for more than 12 years. only the africanized honey bees removed a significant proportion of varroa-infested brood, when the data was corrected for brood removal from control cells.
Controle genético da regenera??o in vitro em progênies de Eucalyptus grandis
Bravo, Carlos David Vera;Gonalves, Ant?nio Natal;Dias, Carlos Tadeu dos Santos;Vencovsky, Roland;
Ciência Rural , 2008, DOI: 10.1590/S0103-84782008000800014
Abstract: the genetic control of in vitro direct regeneration was tested on seedlings of ten open-pollinated progenies from the base population of atherton origin of eucalyptus grandis at university of s?o paulo (brazil). seeds were germinated in vitro, after twenty days, distal hypocotyls segments from 196 seedlings per progeny were inoculated in culture media at generalized complete randomized block design, with two experimental units per block and seven repetitions, using the interaction blocks by progenies as an estimate of the experimental error. at week 14 from the inoculation bud induction was evaluated. regeneration among progenies were significantly different (p<0.0001). regeneration varied from 11 to 60%. the narrow-sense heritability between means of experimental units for in vitro regeneration was height. (h2m=0.94), indicating a strong genetic control of the trait within the population and also a high maternal effect. high variability within the study sample was found.
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