Tendencias cognitivas y procesos de abstracción en el aprendizaje del Álgebra y de la Geometría

In the present paper we discuss eleven kinds of phenomena which make themselves manifest at the time students are learning new mathematical concepts and operations. These phenomena can be observed both in the classroom and during clinical interviews. When learning mathematics, new rules are constantly being formed, due to the fact that new ways are found to extend conceptual networks previously developed. A central aspect in this point of view is the idea of sense, as opposed to meaning, when speaking about an MSS. In all the cornments, we have tried to distinguish between these two notions: meaning and sense

El aprendizaje del álgebra escolar desde una perspectiva psicológica

Este artículo describe algunas de las principales contribuciones de la investigación al creciente conocimiento de los procesos cognitivos que implica el aprendizaje del álgebra en las escuelas secundarias. También se discuten los intentos continuos de los investigadores para desarrollar una teoría sobre la enseñanza / aprendizaje del álgebra. Finalmente, se mencionan algunas tendencias futuras en la enseñanza / aprendizaje del álgebra

Cabezal del receptor del continuo con dos polarizaciones

Se describe el cabezal del nuevo receptor del IAR para observaciones del continuo con dos polarizaciones. El proyecto incluye el diseño de un alimentador de tipo escalar, sistemas para la obtención de las dos polarizaciones, osciladores de alta frecuencia, amplificadores de bajo ruido y etapas de frecuencia intermedia.Asociación Argentina de Astronomí

Polarímetro para observaciones en el continuo en 1420 MHz

Se describe el cabezal de un nuevo receptor capaz de detectar señales polarizadas, cuya construcción se está llevando a cabo en el Instituto Argentino de Radioastronomía. Se mencionan los criterios de diseño aplicados en las siguientes etapas del sistema como así también el estado actual de los trabajos.Asociación Argentina de Astronomí

El depósito de armas de la azucarera (Alfaro, La Rioja)

En el presente artículo se trata el hallazgo de un depósito de armas: espadas, puñal, casco y umbos de escudo, principalmente, localizados durante la excavación realizada en el año 1969 en la Azucarera de Alfaro (La Rioja). El material es bastante significativo dentro del contexto peninsular. Parece tratarse de un depósito ritual de la guerra sertoriana, de ahí su importancia y el interés de su publicación

Lack of association between TLR4 rs4986790 polymorphism and risk of cardiovascular disease in patients with rheumatoid arthritis

This is copy of an article published in the DNA and cell biology 2012 © Mary Ann Liebert, Inc.; DNA and cell bilogy is available online at: http://online.liebertpub.comRheumatoid arthritis (RA) is a chronic inflammatory disease associated with increased cardiovascular (CV) mortality. Toll-like receptor-4 (TLR4) activates the innate immune response via NF-kB pathway and mitogenactivated protein kinase signaling, leading to expression of proinflammatory cytokines and chemokines. The G allele of TLR4 rs4986790 (+ 896A > G, Asp299Gly) gene polymorphism has been implicated in reduction of risk of atherosclerosis. In this study, 1481 RA patients fulfilling the 1987 American College of Rheumatology (ACR) criteria were genotyped for the rs4986790 TLR4 variant to determine the influence of this variant in the risk of CV events in these patients. Also, HLA-DRB1 status was determined using molecular based methods. Moreover, potential influence of rs4986790 variant in the development of subclinical atherosclerosis was assessed in a subgroup of RA patients with no history of CV events by the measurement of surrogate markers of subclinical atherosclerosis. No statistically significant differences in allele or genotype frequencies for the rs4986790 variant between RA patients who experienced CV events or not were found. Likewise, no significant association between this gene variant and any of the surrogate markers of subclinical atherosclerosis was found. In summary, results in our study do not support the hypothesis that the rs4986790 (+ 896A > G, Asp299Gly) TLR4 variant may influence predisposition for subclinical atherosclerosis and clinically evident CV disease in RA patientsThis study was supported by two grants from Fondo de Investigaciones Sanitarias PI06-0024 and PS09/00748 (Spain). This work was partially supported by RETICS Program, RD08/0075 (RIER) from Instituto de Salud Carlos III (ISCIII), within the VI PN de I +D+ i 2008–2011 (FEDER). M.G.B. is supported by a grant from Fundación Española de Reumatología (FER). R.L.M. is supported by a grant by IFIMAV, Santander (Spain)

CARD8 rs2043211 (p.C10X) polymorphism is not associated with disease susceptibility or cardiovascular events in spanish rheumatoid arthritis patients

This is a copy of an article published in the DNA Cell Biology (01-01-2013) copyright Mary Ann Liebert, Inc. DNA Cell Biology is avalaible online at: http://online.liebertpub.comRheumatoid arthritis (RA) is a complex polygenic inflammatory disease associated with accelerated atherosclerosis, which is the main cause of increased cardiovascular (CV) morbidity and mortality in RA patients. CARD8 is a constituent of inflammasome, which regulates interleukin 1-beta production, and has been associated with a worse disease course in early RA. One thousand six hundred twenty-one patients fulfilling the 1987 ACR classification criteria for RA and 1300 matched controls, were genotyped for the CARD8 rs2043211 (30T > A, p.C10X) single-nucleotide polymorphism (SNP) using predesigned TaqMan SNP genotyping assay. The genotyping success rate in our study was greater than 94%. We assessed CARD8 rs2043211 gene polymorphism results in 1530 Spanish RA patients in whom information on CV disease and CV risk factors was available at the time of the study. Also, a subgroup of patients with no history of CV events (n = 276) was assessed for the potential influence of the rs2043211 variant in the development of subclinical atherosclerosis, by measurement of carotid intima-media thickness (IMT) and presence of carotid plaques. No statistically significant differences in allele or genotype frequencies for the rs2043211 CARD8 gene variant between patients with RA and controls were seen. Similarly, CARD8 rs2043211 (30T > A, p.C10X) SNP did not influence the development of CV events or the risk of CV events throughout the time. Likewise, no significant association between this gene variant and carotid IMT or the presence of plaques was found. In summary, our results do not support a role of the CARD8 rs2043211 gene variant in susceptibility to RA or in the development of CV disease in patients with RAThis work was supported by grants from Fondo de Investigaciones Sanitarias PI06-0024 and PS09/00748 (Spain), and by RETICS Program, RD08/0075 (RIER) from Instituto de Salud Carlos III (ISCIII), within the VI PN de I +D+ i 2008–2011 (FEDER). M.G.B. is a beneficiary of a grant from Fundación Española de Reumatología (FER)

The influence of technology on the mathematical modelling of physical phenomena

A study is presented in which students are asked to model two physical phenomena using applications on electronic tablets : a bounce of a ball and the extension of a spring. The analysis focusses on (a) the influence of characteristics of the applications on the tablets on the decisions that groups of 16-year-old students made during the modelling phases in which reality and mathematics are related, (b) mathematisation of the phenomena and (c) interpretation of the models. The phenomena were recorded using an app that requests users establish a set of references during the mathematisation process, which makes students focus on the way the references have been set to interpret the model properly. Our findings indicated inconsistences between student decisions made during mathematisation and their considerations during interpretation of the model. To conclude we suggest reasons students experience problems in working without a pre-defined reference syste

The presence of both HLA-DRB1[*]04:01 and HLA-B[*]15:01 increases the susceptibility to cranial and extracranial giant cell arteritis.

Objectives: To determine if patients with the predominant extracranial large-vessel-vasculitis (LVV) pattern of giant cell arteritis (GCA) have a distinctive HLA-B association, different from that reported in biopsy-proven cranial GCA patients. In a further step we assessed if the combination of HLA-B and HLA-DRB1 alleles confers an increased risk for GCA susceptibility, either for the cranial and extracranial LVV phenotypes. Methods: A total of 184 patients with biopsy-proven cranial GCA, 105 with LVV-GCA and 486 healthy controls were included in our study. We compared HLA-B phenotype frequencies between the three groups. Results: HLA-B*15 phenotype was significantly increased in patients with classic cranial GCA compared to controls (14.7% versus 5.8%, respectively; p<0.01; OR [95% CI] =2.81 [1.54-5.11]). It was mainly due to the HLA-B*15:01 allele (12.5% versus 4.0%, respectively; p<0.01; OR [95% CI] =3.51 [1.77-6.99]) and remained statistically significant after Bonferroni correction. Similar HLA-B*15 association was observed in patients with the LVV-GCA (11.4% versus 5.8%, p=0.04, OR [95% CI] =2.11 [1.04-4.30]). This association was also mainly due to the HLA-B*15:01 allele (10.5% versus 4.0%, respectively; p=0.0054; OR [95% CI] =2.88 [1.19-6.59]). Noteworthy, the presence of HLA-B*15:01 together with HLA-DRB1*04:01 led to an increased risk of developing both cranial and extracranial LVV-GCA. Conclusions: Susceptibility to GCA is strongly related to the HLA region, regardless of the clinical phenotype of expression of the disease.This work was partially supported by RETICS Programs, RD08/0075 (RIER), RD12/0009/0013 and RD16/0012 from ‘‘Instituto de Salud Carlos III’’ (ISCIII) (Spain). However, this research did not receive any specific grant from funding agencies in the commercial or not-for-profit sectors

Influence of elevated-CRP level-related polymorphisms in non-rheumatic Caucasians on the risk of subclinical atherosclerosis and cardiovascular disease in rheumatoid arthritis

Association between elevated C-reactive protein (CRP) serum levels and subclinical atherosclerosis and cardiovascular (CV) events was described in rheumatoid arthritis (RA). CRP, HNF1A, LEPR, GCKR, NLRP3, IL1F10, PPP1R3B, ASCL1, HNF4A and SALL1 exert an influence on elevated CRP serum levels in non-rheumatic Caucasians. Consequently, we evaluated the potential role of these genes in the development of CV events and subclinical atherosclerosis in RA patients. Three tag CRP polymorphisms and HNF1A, LEPR, GCKR, NLRP3, IL1F10, PPP1R3B, ASCL1, HNF4A and SALL1 were genotyped in 2,313 Spanish patients by TaqMan. Subclinical atherosclerosis was determined in 1,298 of them by carotid ultrasonography (by assessment of carotid intima-media thickness-cIMT-and presence/absence of carotid plaques). CRP serum levels at diagnosis and at the time of carotid ultrasonography were measured in 1,662 and 1,193 patients, respectively, by immunoturbidimetry. Interestingly, a relationship between CRP and CRP serum levels at diagnosis and at the time of the carotid ultrasonography was disclosed. However, no statistically significant differences were found when CRP, HNF1A, LEPR, GCKR, NLRP3, IL1F10, PPP1R3B, ASCL1, HNF4A and SALL1 were evaluated according to the presence/absence of CV events, carotid plaques and cIMT after adjustment. Our results do not confirm an association between these genes and CV disease in RA