Estudio del comportamiento mecánico de morteros modificados con fibras de aserrín bajo esfuerzos de compresión

In this paper, a study about the mechanical behavior of mortar modified with sawdust fibers under compression load was performed. Density, compressive strength and dynamic elastic modulus of mortar modified with 0, 0,5, 1 and 3% of sawdust were estimated. Composites were evaluated after 7, 30 and 90 days of curing. In addition, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) were used ton chracterize the morphology and to find elemental composition for both, fibers and cement matrix. The results show that compressive strentgth, elastic modulus and density decreases as sawdust percentage increases. It is suggested to use 1% of sawdust fiber mortars in order to avoid an important reduction of the mortar mechanical properties. En este artículo, se presenta un estudio sobre el comportamiento mecánico de morteros modificados con fibras de aserrín bajo cargas de compresión. Se estimó la densidad, resistencia a la compresión, y el módulo de elasticidad dinámico de morteros modificados con 0, 0,5, 1 y 3% en peso de fibra de aserrín. Los compuestos fueron evaluados luego de 7, 30 y 90 días de curado. Además, se utilizó microscopia electrónica de barrido (SEM) y espectroscopía de rayos X de energía dispersa (EDX) para caracterizar la morfología y encontrar la composición elemental tanto de las fibras como de la matriz de cemento. Los resultados muestran que a mayor porcentaje de aserrín, la resistencia, el módulo de elasticidad y la densidad disminuyen. Se sugiere utilizar hasta 1% de fibra de aserrín en morteros para evitar una reducción importante en las propiedades mecánicas de los morteros.

Applied approach to the spaces constitutive of collective identity in social movement: case study of the anti-eviction movement and the squatting movement in Spain

Cuando las experiencias sociales no se corresponden con las expectativas, es decir, cuando la regulación social dista de la esperada emancipación social, se descubre que determinados colectivos vinculan sus luchas sociales a la consecución de unos derechos subjetivamente usurpados. Para ello constituyen espacios múltiples en los cuales se ponen en común las problemáticas y se comienza, por ende, a visibilizar sus posibles soluciones. En esta línea, vislumbramos la forma en que estos espacios de socialización terminan por re-definirse en espacios de acción colectiva. Teniendo esto en cuenta, en el presente artículo presentamos el resultado de una investigación etnográfica comparativa de dos movimientos sociales con manifiestas diferencias simbólicas, políticas, culturales y sociales, pero que confluyen en un eje vertebrador común: el derecho a una vivienda digna. Estos son, por una parte, el movimiento de okupación y, por otra, la lucha antidesahucios, materializada en la Plataforma de Afectados por la Hipoteca (PAH). Ambos desarrollan prácticas culturales similares en los distintos espacios de socialización a través de sus respectivos repertorios y espacios de acción colectiva. Tras un análisis desde la antropología implicada, se concluye que estos espacios, ya sean físicos —centros sociales, bares, plazas, etc.— o simbólicos —manifestaciones, concentraciones, fiestas, etc.—, sirven para reconfigurar y reforzar las identidades personales y colectivas a través de la puesta en común de prácticas y experiencias reivindicativas.When social experiences do not correspond to expectations, that is, when social regulation is far from the expected social emancipation, we discover that certain communities link their social struggles to the achievement of some subjectively usurped rights. To this end, they constitute multiple spaces in which problems are shared and thus begin to make visible their possible solutions. In this sense, we discern the way in which these spaces of socialization end up redefining themselves in spaces of collective action. With this in mind, in this article we present the result of a comparative ethnographic research of two social movements with obvious symbolic, political, cultural and social differences, but which converge in a common mainstay: the right to decent housing. These are, on the one hand, the squatting movement and, on the other, the anti-eviction struggle, materialized in the Platform of People Affected by Mortgages (PAH, by its Spanish initials). Both develop similar cultural practices in the different spaces of socialization through their respective struggles and spaces of collective action. After an analysis from the applied anthropology, it is concluded that these spaces, whether physical — social centers, bars, squares, etc. — or symbolic —demonstrations, rallies, parties, etc. — serve to reconfigure and reinforce personal and collective identities through the sharing of demanding practices and experiences

Enhancing adult hippocampal neurogenesis with lysophosphatidic acid: a proposal for erasing cocaine contextual memory

Stimulating adult hippocampal neurogenesis (AHN) has been uncovered as a promising approach in the manipulation of retrograde memories. This work aims to study whether increasing AHN with lysophosphatidic acid (LPA, an endogenous lysophospholipid with proneurogenic actions) promotes the forgetting of previously established cocaine-contextual associations. C57BL/6J mice previously trained in a cocaine-induced conditioned place preference (CPP) paradigm were submitted to 23 days of withdrawal, during which they received repeated intracerebroventricular infusions of LPA, ki16425 (a selective LPA1/3 receptors antagonist), or vehicle solution. Then, CPP maintenance was assessed, and the causal role of AHN in this process was evaluated using a mediation analysis. In a complementary experiment, wild-type and LPA1-null mice were acutely infused with LPA or ki16425 to determine the involvement of the LPA1 receptor in the in vivo proneurogenic actions of LPA. The chronic LPA treatment significantly weakened the long-term retention of a previously acquired cocaine-CPP memory, an effect clearly mediated by a LPA-induced increase in the number of adult-born dentate granule cells. In contrast, the ki16425-treated mice displayed aberrant responses of initially decreased CPP retention that progressively increased CPP across the extinction sessions, in absence of effects on AHN. The histological studies suggested that the proneurogenic actions of LPA were related to the enhancement of cell proliferation and critically depended on the LPA1 receptor function. Our results suggest that the LPA/LPA1-pathway acts as a potent in vivo modulator of AHN, and highlight the usefulness of a post-learning increase of adult-born hippocampal neurons as a strategy to promote the forgetting of cocaine-context associations.Plan Propio de Investigación y Transferencia. Campus de Excelencia Internacional Andalucía Tech. Spanish Ministry of Economy and Competitiveness (Agencia Estatal de Investigación), co‐funded by the European Research Development Fund (AEI/FEDER, UE) (PSI2013‐44901‐P and PSI2017‐82604‐R to L.J.S. and PSI2015‐73156‐JIN to E.C.O.); by the National System of Health‐Instituto de Salud Carlos III, which is co‐funded by AEI/FEDER, UE (Red de Trastornos Adictivos; RD16/0017/0001 to F.R.d.F.); and by the Andalusian R&D&I Programme, Regional Ministry of Economy and Knowledge (PAIDI CTS643 to G.E.T.). D.L.G.M. hold a FPU grant from the Spanish Ministry of Education, Culture and Sports (FPU13/04819 ). F.R.d.F. and G.E.T. are supported by Nicolas Monardes Programme, from the Andalusian Regional Ministry of Health. E.C.O. holds a ‘Jóvenes Investigadores’ grant (code: PSI2015‐73156‐JIN) from the Spanish Ministry of Economy and Competitiveness (Agencia Estatal de Investigación), which is co‐funded by the AEI/FEDER, UE

Cytokine pathway disruption in a mouse model of schizophrenia induced by Munc18-1a overexpression in the brain

Background: An accumulating body of evidence points to the significance of neuroinflammation and immunogenetics in schizophrenia, and an imbalance of cytokines in the central nervous system (CNS) has been suggested to be associated with the disorder. Munc18-overexpressing mice (Munc18-OE) have provided a model for the study of the alterations that may underlie the symptoms of subjects with schizophrenia. The aim of the present study was to elucidate the involvement of neuroinflammation and cytokine imbalance in this model. Methods: Cytokines were evaluated in the cortex and the striatum of Munc18-OE and wild-type (WT) mice by enzyme-linked immunosorbent assay (ELISA). Protein levels of specific microglia and macrophage, astrocytic and neuroinflammation markers were quantified by western blot in the cortex and the striatum of Munc18-OE and WT mice. Results: Each cytokine evaluated (Interferon-gamma (IFN-γ), Tumor Necrosis Factor-alpha (TNF-α), Interleukin-2 (IL-2) and CCL2 chemokine) was present at higher levels in the striatum of Munc18-OE mice than WT. Cortical TNF-α and IL-2 levels were significantly lower in Munc18-OE mice than WT mice. The microglia and macrophage marker CD11b was lower in the cortexes of Munc18-OE mice than WT, but no differences were observed in the striatum. Glial Fibrillary Acidic Protein (GFAP) and Nuclear Factor-kappaB (NF-κB)p65 levels were not different between the groups. Interleukin-1beta (IL-1β) and IL-6 levels were beneath detection limits. Conclusions: The disrupted levels of cytokines detected in the brain of Munc18-OE mice was found to be similar to clinical reports and endorses study of this type for analysis of this aspect of the disorder. The lower CD11b expression in the cortex but not in the striatum of the Munc18-OE mice may reflect differences in physiological activity. The cytokine expression pattern observed in Munc18-OE mice is similar to a previously published model of schizophrenia caused by maternal immune activation. Together, these data suggest a possible role for an immune imbalance in this disorder

Study on child welfare of adopted chinese children at schools in Castilla y León

[ES] nuevos desafíos sociales que deben ser abordados. Más allá de los procesos de aprendizaje propios de los centros escolares, se percibe a la escuela como el espacio idóneo para que niños, niñas y adolescentes desarrollen habilidades y comportamientos que les permitan vivir en sociedad y como un escenario de confluencia para culturas totalmente diferenciadas. En el caso de España, la llegada de los niños adoptados de origen chino contribuyó a aumentar la diversidad étnica de la población española en las aulas, y con ello los desafíos para la institución educativa. El objetivo principal de esta investigación estriba en conocer el bienestar social de los niños y niñas adoptados en la R.P. China que cursan la Educación Secundaria en Castilla y León, dado que se presenta como un grupo potencialmente expuesto a las tensiones que se generan en contextos educativos heterogéneos. Para alcanzar el objetivo se han realizado 10 entrevistas semiestructuradas. La estrategia analítica seguida se asienta en la teoría fundamentada. Los resultados muestran que es un grupo objeto de burla por sus rasgos fenotípicos asiáticos, pero no por su condición de adoptados. [EN] The increasing diversity in schools as a result of international adoption has created new social challenges that need to be addressed. Beyond the learning processes of schools, the school is perceived as the ideal space for children and adolescents to develop skills and behaviours that allow them to live in society and it is considered a meeting point of different cultures. In the case of Spain, adopted Chinese children contributed to ethnic diversity in the classrooms, and the schools had to face this challenge. The main objective of this study is to know the social well-being of children adopted in the Republic of China who attend Secondary Education in Castile and Leon since it presents itself as a group potentially exposed to the tensions that arise in heterogeneous groups in educational settings. Ten semi-structured interviews were conducted to meet the objective. The analytical strategy mfollowed is based on well-founded theory. The results show that it is a group mocked for its Asian phenotypic features, but not for its adopted status

Educação e escola na Espanha em tempos de pandemia

The work we offer aims to problematize the new education that emerged because of the health crisis. The methodology focuses on taking advantage of the sources of information available in the documentary archives of public organizations (reports and statistics) and of the bibliographic documentation (academic). The results of the analysis lead us to a trilogy of interpretation: the socio-educational perspective of the crisis, the differential involvement and response in relation to public/private education and the new interpretation of social participation in education. Finally, the impact of the pandemic on education and a call to attention to the use and/or abuse of online education.El trabajo que ofrecemos pretende problematizar la nueva educación surgida a raíz de la crisis sanitaria. La metodología se centra en el aprovechamiento de las fuentes de información disponibles en los archivos documentales de los organismos públicos (informes y estadísticas) y de la documentación bibliográfica (académica). Los resultados del análisis nos conducen a un triángulo de interpretación: la perspectiva socioeducativa de la crisis, la implicación y respuesta diferencial en relación con la educación pública/privada y la nueva interpretación de la participación social en la educación. Finalmente, se aborda el impacto de la pandemia en la educación y se realiza una llamada de atención al uso y/o abuso de la educación online.O trabalho que oferecemos visa problematizar a nova formação que emergiu a partir da crise da saúde. A metodologia centra-se no aproveitamento das fontes de informação disponíveis nos arquivos documentais de organismos públicos (relatórios e estatísticas) e da documentação bibliográfica (académica). Os resultados da análise nos levam a uma trilogia de interpretação: a perspectiva socioeducativa da crise, o envolvimento e a resposta diferenciada em relação à educação público/privada e a nova interpretação da participação social na educação. Finalmente, o impacto da pandemia na educação e um chamado à atenção para o uso e/ou abuso da educação online

MEP pathway products allosterically promote monomerization of deoxy-D-xylulose-5-phosphate synthase to feedback-regulate their supply

Isoprenoids are a very large and diverse family of metabolites required by all living organisms. All isoprenoids derive from the double-bond isomers isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP), which are produced by the methylerythritol 4-phosphate (MEP) pathway in bacteria and plant plastids. It has been reported that IPP and DMAPP feedback-regulate the activity of deoxyxylulose 5-phosphate synthase (DXS), a dimeric enzyme that catalyzes the main flux-controlling step of the MEP pathway. Here we provide experimental insights into the underlying mechanism. Isothermal titration calorimetry and dynamic light scattering approaches showed that IPP and DMAPP can allosterically bind to DXS in vitro, causing a size shift. In silico ligand binding site analysis and docking calculations identified a potential allosteric site in the contact region between the two monomers of the active DXS dimer. Modulation of IPP and DMAPP contents in vivo followed by immunoblot analyses confirmed that high IPP/DMAPP levels resulted in monomerization and eventual aggregation of the enzyme in bacterial and plant cells. Loss of the enzymatically active dimeric conformation allows a fast and reversible reduction of DXS activity in response to a sudden increase or decrease in IPP/DMAPP supply, whereas aggregation and subsequent removal of monomers that would otherwise be available for dimerization appears to be a more drastic response in the case of persistent IPP/DMAPP overabundance (e.g., by a blockage in their conversion to downstream isoprenoids). Our results represent an important step toward understanding the regulation of the MEP pathway and rational design of biotechnological endeavors aimed at increasing isoprenoid contents in microbial and plant systems

The structure of the R2TP complex defines a platform for recruiting diverse client proteins to the HSP90 molecular chaperone system

The R2TP complex, comprising the Rvb1p-Rvb2p AAA-ATPases, Tah1p, and Pih1p in yeast, is a special- ized Hsp90 co-chaperone required for the assembly and maturation of multi-subunit complexes. These include the small nucleolar ribonucleoproteins, RNA polymerase II, and complexes containing phosphati- dylinositol-3-kinase-like kinases. The structure and stoichiometry of yeast R2TP and how it couples to Hsp90 are currently unknown. Here, we determine the 3D organization of yeast R2TP using sedimenta- tion velocity analysis and cryo-electron microscopy. The 359-kDa complex comprises one Rvb1p/Rvb2p hetero-hexamer with domains II (DIIs) forming an open basket that accommodates a single copy of Tah1p-Pih1p. Tah1p-Pih1p binding to multiple DII do- mains regulates Rvb1p/Rvb2p ATPase activity. Using domain dissection and cross-linking mass spectro- metry, we identified a unique region of Pih1p that is essential for interaction with Rvb1p/Rvb2p. These data provide a structural basis for understanding how R2TP couples an Hsp90 dimer to a diverse set of client proteins and complexes