Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99


Any time

2019 ( 67 )

2018 ( 381 )

2017 ( 392 )

2016 ( 591 )

Custom range...

Search Results: 1 - 10 of 212459 matches for " Olga León "
All listed articles are free for downloading (OA Articles)
Page 1 /212459
Display every page Item
Bilingualism of Colombian Deaf Children in the Teaching-Learning of Mathematics in the First Year of Elementary School
León Corredor,Olga Lucía; Calderón,Dora Inés;
Colombian Applied Linguistics Journal , 2010,
Abstract: this paper summarizes some results of the first ethnographic research study conducted in colombia in three different elementary schools for deaf children in which bilingualism (sign-language and written-language) is starting to be emphasized. this study focuses on the teaching of mathematics in classrooms for deaf children using contexts proclaimed as bilingual. the participants in the study were first grade teachers. the analysis presented in this paper illustrates the struggles that teachers experience teaching arithmetic in such a context. the teaching of arithmetic using bilingualism requires three types of semiotic registers: sign-language and written-spanish, and the hindu-arabic numeration system. the analysis indicates some puzzling teaching-learning issues interweaving language and mathematics. these issues are of linguistic and communicative, social and cultural, and cognitive and pedagogical nature.
Yara Patricia Saavedra Vélez,Olga Patricia Pineda León
Estudios Gerenciales , 2001,
Effects of nimesulide on kainate-induced in vitro oxidative damage in rat brain homogenates
Candelario-Jalil Eduardo,Sonia León Olga
BMC Pharmacology , 2003, DOI: 10.1186/1471-2210-3-7
Abstract: Background The cyclooxygenase-2 inhibitor nimesulide is able to reduce kainate-induced oxidative stress in vivo. Here we investigate if this effect is mediated by the direct antioxidant properties of nimesulide using a well-characterized in vitro model of kainate toxicity. Results Exposure of rat brain homogenates to kainate (12 mM) caused a significant (p < 0.01) increase in the concentrations of malondialdehyde and 4-hydroxy-alkenals and a significant (p < 0.01) decrease in sulfhydryl levels. High concentrations of nimesulide (0.6–1.6 mM) reduced the extent of lipid peroxidation and the decline in both total and non-protein sulfhydryl levels induced by kainate in a concentration-dependent manner. Conclusions Our results suggest that the neuroprotective effects of nimesulide against kainate-induced oxidative stress in vivo are not mediated through its direct free radical scavenging ability because the concentrations at which nimesulide is able to reduce in vitro kainate excitotoxicity are excessively higher than those attained in plasma after therapeutic doses.
Modeling the Lion Attack in Cognitive Radio Networks
Juan Hernandez-Serrano,Olga León,Miguel Soriano
EURASIP Journal on Wireless Communications and Networking , 2011, DOI: 10.1155/2011/242304
Modeling the Lion Attack in Cognitive Radio Networks
Hernandez-Serrano Juan,León Olga,Soriano Miguel
EURASIP Journal on Wireless Communications and Networking , 2011,
Abstract: Cognitive radio is a promising technology aiming to improve the utilization of the radio electromagnetic spectrum. A cognitive radio is a smart device which runs radio applications software to perform signal processing. The use of this software enables the device to sense and understand its environment and actively change its mode of operation based on its observations. Unfortunately, this solution entails new security challenges. In this paper, we present a cross-layer attack to TCP connections in cognitive radio networks, analyze its impact on TCP throughput via analytical model and simulation, and propose potential countermeasures to mitigate it.
Funcionalidad de una mezcla de gomas de Acacia glomerosa, Enterolobium cyclocarpum e Hymenaea courbaril en la preparación de helados de bajo contenido calórico
Rincón,Fernando; León de Pinto,Gladys; Beltrán,Olga; Clamens,Carmen; Guerrero,Rocío;
Revista Científica , 2008,
Abstract: acacia glomerosa, enterolobium cyclocarpum and hymenaea courbaril, species widely disseminated in venezuela, south america, produce gum with good yield. the mixture of these gums was tested as stabilizer in the low fat ice cream preparation. viscosity, overrun, foam expansion, meltdown, shape factor and sensory properties were determined. these quality characteristics were compared with those exhibited by the product obtained with a mixture of commercial gums. the mixture tested provided the suitable viscosity for the ice cream mix with the corresponding overrun and texture. it gave better foaming properties and air incorporation. on the other hand, it was demonstrated the good sensory attributes by the highest score i.e. appearance (7.78), creaminess (7.62), flavor (8.01) and lowest score of iciness (3.06). this work showed good functionality as stabilizer of the mixture of gums investigated in the low fat ice cream preparation.
Comportamiento de algunos factores de riesgo para malformaciones congénitas mayores en el municipio de Ranchuelo Behavior of some risk factors for major congenital malformations in Ranchuelo municipality
Noel Taboada Lugo,Clara León Mollinedo,Suyén Martínez Chao,Olga Díaz Inufio
Revista Cubana de Obstetricia y Ginecolog?-a , 2006,
Abstract: Se define como malformación congénita mayor a los defectos que tienen un compromiso funcional o estético importante para la vida del individuo, por lo que tienen consecuencias médicas, requieren de atención temprana, algunas veces de urgencia y, por tanto, tienen también repercusión psicosocial. Se realizó un estudio analítico de casos y controles con el objetivo de clasificar las malformaciones congénitas mayores que incidieron en la mortalidad infantil o fetal en el municipio de Ranchuelo, en el período de enero de 1999 a diciembre de 2003, para determinar la efectividad de los diferentes métodos de diagnóstico prenatales e identificar los factores de riesgo que se asociaron a estas. El universo de trabajo quedó constituido por 25 casos (21 mujeres con historia de interrupción de la gestación por causa genética y 4 con antecedentes de al menos un hijo(a) fallecido por malformaciones congénitas) y se seleccionó igual cantidad de controles. Las malformaciones que más incidieron fueron las del sistema nervioso, digestivo y genitourinario. La efectividad del ultrasonido en el diagnóstico prenatal fue de 88 % y cuando se combinó con la cuantificación de Alfafeto proteína en suero materno, fue de un 100 % para el diagnóstico de los defectos congénitos abiertos. Los factores de riesgo que se asociaron con las malformaciones fueron los antecedentes familiares de estos defectos, los hábitos tóxicos y los antecedentes de amenaza de aborto, con un riesgo atribuible de 0.46, 0.37 y 0.32, respectivamente. Se hacen recomendaciones. Congenital malformation is defined as the defects having an important functional or aesthetic compromise for the individual's life, so they have medical consequences, require early attention, sometimes of emergency and, therefore, they also have a psychosocial impact. An analytical case-control study was conducted aimed at classifying the major congenital malformations influencing on children or fetal mortality in Ranchuelo municipality from January 1999 to December 2003 to determine the effectivity of the different prenatal diagnostic methods and to identify the risk factors associated with them. The working universe was composed of 25 cases (21 women with history of abortion due to genetic cause and 4 with previous history of at least a dead child as a result of congenital malformations). The same number of controls was selected. The malformations affecting the most were those of the nervous, digestive and genitourinary system. The efficacy of ultrasound in the prenatal diagnosis was 88 %, and when it was combined with the quantificati
The Antinociceptive Effects of JWH-015 in Chronic Inflammatory Pain Are Produced by Nitric Oxide-cGMP-PKG-KATP Pathway Activation Mediated by Opioids
Roger Negrete, Arnau Hervera, Sergi Leánez, Jesús M. Martín-Campos, Olga Pol
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0026688
Abstract: Background Cannabinoid 2 receptor (CB2R) agonists attenuate inflammatory pain but the precise mechanism implicated in these effects is not completely elucidated. We investigated if the peripheral nitric oxide-cGMP-protein kinase G (PKG)-ATP-sensitive K+ (KATP) channels signaling pathway triggered by the neuronal nitric oxide synthase (NOS1) and modulated by opioids, participates in the local antinociceptive effects produced by a CB2R agonist (JWH-015) during chronic inflammatory pain. Methodology/Principal Findings In wild type (WT) and NOS1 knockout (NOS1-KO) mice, at 10 days after the subplantar administration of complete Freund's adjuvant (CFA), we evaluated the antiallodynic (von Frey filaments) and antihyperalgesic (plantar test) effects produced by the subplantar administration of JWH-015 and the reversion of their effects by the local co-administration with CB2R (AM630), peripheral opioid receptor (naloxone methiodide, NX-ME) or CB1R (AM251) antagonists. Expression of CB2R and NOS1 as well as the antinociceptive effects produced by a high dose of JWH-015 combined with different doses of selective L-guanylate cyclase (ODQ) or PKG (Rp-8-pCPT-cGMPs) inhibitors or a KATP channel blocker (glibenclamide), were also assessed. Results show that the local administration of JWH-015 dose-dependently inhibited the mechanical and thermal hypersensitivity induced by CFA which effects were completely reversed by the local co-administration of AM630 or NX-ME, but not AM251. Inflammatory pain increased the paw expression of CB2R and the dorsal root ganglia transcription of NOS1. Moreover, the antinociceptive effects of JWH-015 were absent in NOS1-KO mice and diminished by their co-administration with ODQ, Rp-8-pCPT-cGMPs or glibenclamide. Conclusions/Significance These data indicate that the peripheral antinociceptive effects of JWH-015 during chronic inflammatory pain are mainly produced by the local activation of the nitric oxide-cGMP-PKG-KATP signaling pathway, triggered by NOS1 and mediated by endogenous opioids. These findings suggest that the activation of this pathway might be an interesting therapeutic target for the treatment of chronic inflammatory pain with cannabinoids.
The Spinal Cord Expression of Neuronal and Inducible Nitric Oxide Synthases and Their Contribution in the Maintenance of Neuropathic Pain in Mice
Arnau Hervera,Roger Negrete,Sergi Leánez,Jesús M. Martín-Campos,Olga Pol
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0014321
Abstract: Nitric oxide generated by neuronal (NOS1), inducible (NOS2) or endothelial (NOS3) nitric oxide synthases contributes to pain processing, but the exact role of NOS1 and NOS2 in the maintenance of chronic peripheral neuropathic pain as well as the possible compensatory changes in their expression in the spinal cord of wild type (WT) and NOS knockout (KO) mice at 21 days after total sciatic nerve ligation remains unknown.
Peripheral effects of morphine and expression of μ-opioid receptors in the dorsal root ganglia during neuropathic pain: nitric oxide signaling
Arnau Hervera, Roger Negrete, Sergi Leánez, Jesús M Martín-Campos, Olga Pol
Molecular Pain , 2011, DOI: 10.1186/1744-8069-7-25
Abstract: In wild type (WT) mice, the subplantar administration of morphine dose-dependently decreased the mechanical and thermal allodynia induced by the chronic constriction of the sciatic nerve (CCI), which effects were significantly diminished after their co-administration with different subanalgesic doses of a selective NOS1 (N-[(4S)-4-amino-5-[(2-aminoethyl)amino]pentyl]-N'-nitroguanidine tris(trifluoroacetate) salt; NANT), NOS2 (L-N(6)-(1-iminoethyl)-lysine; L-NIL), L-guanylate cyclase (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one; ODQ), PKG ((Rp)-8-(para-chlorophenylthio)guanosine-3',5'-cyclic monophosphorothioate; Rp-8-pCPT-cGMPs) inhibitor or a KATP channel blocker (glibenclamide). The evaluation of the expression of MOR in the dorsal root ganglia from sham-operated and sciatic nerve-injured WT, NOS1 knockout (KO) and NOS2-KO mice at 21 days after surgery demonstrated that, although the basal mRNA and protein levels of MOR were similar between WT and both NOS-KO animals, nerve injury only decreased their expression in WT mice.These results suggest that the peripheral nitric oxide-cGMP-PKG-KATP signaling pathway activation participates in the local antiallodynic effects of morphine after sciatic nerve injury and that nitric oxide, synthesized by NOS1 and NOS2, is implicated in the dorsal root ganglia down-regulation of MOR during neuropathic pain.Neuropathic pain is a clinical manifestation characterized by the presence of allodynia and hyperalgesia and it is difficult to treat with the most potent analgesic compounds. Recent studies have demonstrated that the peripheral administration of μ-opioid receptor (MOR) agonists elicits antinociception in different models of neuropathic pain [1,2] and that their expression decreases after nerve injury [2,3]. Even so, the precise mechanisms implicated in the peripheral actions of morphine as well as in the expression of MOR during neuropathic pain are not completely elucidated.Several studies have shown that nitric oxide, synt
Page 1 /212459
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.