Un estudio comparativo sobre el pensamiento profesional y la "acción docente" de los profesores de ciencias de Educación Secundaria. Parte II

Este artículo es la segunda parte de una investigación más amplia sobre el pensamiento del profesor (Martínez et al., 2001). En este caso el estudio gira en torno al análisis de las diferencias y similitudes entre dos muestras de profesores de ciencias de educación secundaria que difieren en sus años de docencia y en su trayectoria profesional, definida por la realización de cursos de formación permanente de alta cualificación científica y didáctica. En un primer apartado se analizan facetas relacionadas con la motivación y la satisfacción en la realización de su tarea, la manera de entender la formación del profesor y sus percepciones sobre diferentes factores profesionales. A continuación se aborda lo que «dicen hacer» en relación a aspectos curriculares referidos a contenidos, metodología y evaluación. A partir del análisis de las respuestas a los cuestionarios elaborados se plantean una serie de reflexiones que buscarían mejorar el «desarrollo profesional» de este colectivo de profesores.This article is a part of a wider research on secondary science teachers' beliefs. Through the use of a questionnaire data were obtained from 103 secondary science teachers in service with different degrees of experience. Analysis of data are discussed in terms of their implication in teacher training in service

Resonant radiation pressure on neutral particles in a waveguide

A theoretical analysis of electromagnetic forces on neutral particles in an hollow waveguide is presented. We show that the effective scattering cross section of a very small (Rayleigh) particle can be strongly modified inside a waveguide. The coupling of the scattered dipolar field with the waveguide modes induce a resonant enhanced backscattering state of the scatterer-guide system close to the onset of new modes. The particle effective cross section can then be as large as the wavelength even far from any transition resonance. As we will show, a small particle can be strongly accelerated along the guide axis while being highly confined in a narrow zone of the cross section of the guide.Comment: RevTeX,4 pages,3 PS figure

¿Qué pensamiento profesional y curricular tienen los futuros profesores de ciencias de Secundaria?

This article is a part of a wider research on secondary science teachers' beliefs. Through the use of a questionnaire data were obtained from 211 secondary science teacher candidates. Analyses of data are discussed in terms of their implication in science teacher education

Ultrasound-assisted extraction, LC–MS/MS analysis, anticholinesterase, and antioxidant activities of valuable natural netabolites from Astragalus armatus Willd.: In silico molecular docking and In Vitro enzymatic studies

The Astragalus armatus Willd. plant’s phenolic constituent extraction and identification were optimized using the ultrasound-assisted extraction (UAE) method and the LC–MS/MS analysis, respectively. Additionally, cupric reducing antioxidant capacity (CUPRAC), beta carotene, reducing power, DMSO alcalin, silver nanoparticle (SNP)-based method, phenanthroline, and hydroxyl radical tests were utilized to assess the extract’s antioxidant capacity, while the neuroprotective effect was examined in vitro against acetylcholinesterase enzyme. This study accurately estimated the chemical bonding between the identified phenolic molecules derived from LC–MS/MS and the AChE. The extract was found to contain sixteen phenolic substances, and rosmarinic, protocatechuic, and chlorogenic acids, as well as 4-hydroxybenzoic, hyperoside, and hesperidin, were the most abundant substances in the extract. In all antioxidant experiments, the plant extract demonstrated strong antioxidant activity and a significant inhibitory impact against AChE (40.25 ± 1.41 μg/mL). According to molecular docking affinity to the enzyme AChE, the top-five molecules were found to be luteolin, quercetin, naringenin, rosmarinic acid, and kaempferol. Furthermore, these tested polyphenols satisfy the essential requirements for drug-like characteristics and Lipinski’s rule of five. These results highlight the significance of the A. armatus plant in cosmetics, as food additives, and in the pharmaceutical industry due to its rosmarinic and chlorogenic acid content

A hotspot mutation targeting the R-RAS2 GTPase acts as a potent oncogenic driver in a wide spectrum of tumors

A missense change in RRAS2 (Gln to Leu), analogous to the Gln-to-Leu mutation of RAS oncoproteins, has been identified as a long-tail hotspot mutation in cancer and Noonan syndrome. However, the relevance of this mutation for in vivo tumorigenesis remains understudied. Here we show, using an inducible knockin mouse model, that R-Ras2 triggers rapid development of a wide spectrum of tumors when somatically expressed in adult tissues. These tumors show limited overlap with those originated by classical Ras oncogenes. R-Ras2-driven tumors can be classified into different subtypes according to therapeutic susceptibility. Importantly, the most relevant R-Ras2-driven tumors are dependent on mTORC1 but independent of phosphatidylinositol 3-kinase-, MEK-, and Ral guanosine diphosphate (GDP) dissociation stimulator. This pharmacological vulnerability is due to the extensive rewiring by R-Ras2 of pathways that orthogonally stimulate mTORC1 signaling. These findings demonstrate that RRAS2 is a bona fide oncogenic driver and unveil therapeutic strategies for patients with cancer and Noonan syndrome bearing RRAS2 mutations.We thank M. Blázquez and the personnel of the CIC Flow Cytometry, Microscopy, Pathology, and Genomics Units for expert technical work. X.R.B.’s project leading to these results has received funding from the Spanish Association against Cancer (GC16173472GARC), the Castilla-León government (CSI252P18, CSI145P20, and CLC-2017-01), the RTI2018-096481-B-100 grant cofounded by MCIN/AEI/10.13039/501100011033 and the European Research Development Fund “A way of making Europe” of the European Union, and “la Caixa” Banking Foundation (HR20-00164). X.R.B.’s institution is supported by the Programa de Apoyo a Planes Estratégicos de Investigación de Estructuras de Investigación de Excelencia of the Castilla-León government (CLC-2017-01). J.R.-V. received funding from the Carlos III Health Institute (PI20/01724). J.R.-V.’s contract is supported by a senior postdoctoral contract of the Spanish Association against Cancer. L.C.’s contract was supported by contracts from the Spanish Association against Cancer and the CLC-2017-01 grant. L.F.L.-M.’s contract was mostly supported by funding from the Spanish Ministry of Education, Culture and Sports (FPU13/02923) and, subsequently, by the CLC-2017-01 grant. R.C. was supported by a predoctoral contract from the MSI (BES-2016-0077909) and the CLC-2017-01 grant

Intensity Distribution of Modes in Surface Corrugated Waveguides

Exact calculations of transmission and reflection coefficients in surface randomly corrugated optical waveguides are presented. As the length of the corrugated part of the waveguide increases, there is a strong preference to forward coupling through the lowest mode. An oscillating behavior of the enhanced backscattering as a function of the wavelength is predicted. Although the transport is strongly non isotropic, the analysis of the probability distributions of the transmitted waves confirms in this configuration distributions predicted by Random Matrix Theory for volume disorder

Graphene catalyzes the reversible formation of a C–C bond between two molecules

Carbon deposits are well-known inhibitors of transition metal catalysts. In contrast to this undesirable behavior, here we show that epitaxial graphene grown on Ru(0001) promotes the reversible formation of a C–C bond between −CH2CN and 7,7,8,8-tetracyano-p-quinodimethane (TCNQ). The catalytic role of graphene is multifaceted: First, it allows for an efficient charge transfer between the surface and the reactants, thus favoring changes in carbon hybridization; second, it holds the reactants in place and makes them reactive. The reaction is fully reversible by injecting electrons with an STM tip on the empty molecular orbitals of the product. The making and breaking of the C–C bond is accompanied by the switching off and on of a Kondo resonance, so that the system can be viewed as a reversible magnetic switch controlled by a chemical reactionJ.J.N., F.C., R.M., and A.L.V.d.P. acknowledge the Ministerio de Economía y Competitividad (MINECO) project FIS2015-67367-C2-1-P and Comunidad de Madrid projects MAD2D P2013/MIT-3007 and Nanofrontmag S2013/MIT-2850. M.P., C.D., and F.M. acknowledge the MINECO project FIS2016-77889-R and computer time from the CCC-UAM and the Red Española de Supercomputación. C.D. acknowledges a Ramón y Cajal contract from MINECO (Spain). E.M.P., J.V., and B.N.-O. acknowledge the European Research Council project MINT, ERC-StG-2012-307609. IMDEA Nanoscience acknowledges support from the “Severo Ochoa” Programme for Centres of Excellence in R&D (MINECO, grant SEV-2016-0686). IFIMAC acknowledges support from the “María de Maeztu” Programme for Units of Excellence in R&D (MDM-2014-0377

Characterization of mutant versions of the R-RAS2/TC21 GTPase found in tumors

The R-RAS2 GTP hydrolase (GTPase) (also known as TC21) has been traditionally considered quite similar to classical RAS proteins at the regulatory and signaling levels. Recently, a long-tail hotspot mutation targeting the R-RAS2/TC21 Gln72 residue (Q72L) was identified as a potent oncogenic driver. Additional point mutations were also found in other tumors at low frequencies. Despite this, little information is available regarding the transforming role of these mutant versions and their relevance for the tumorigenic properties of already-transformed cancer cells. Here, we report that many of the RRAS2 mutations found in human cancers are highly transforming when expressed in immortalized cell lines. Moreover, the expression of endogenous R-RAS2Q72L is important for maintaining optimal levels of PI3K and ERK activities as well as for the adhesion, invasiveness, proliferation, and mitochondrial respiration of ovarian and breast cancer cell lines. Endogenous R-RAS2Q72L also regulates gene expression programs linked to both cell adhesion and inflammatory/immune-related responses. Endogenous R-RAS2Q72L is also quite relevant for the in vivo tumorigenic activity of these cells. This dependency is observed even though these cancer cell lines bear concurrent gain-of-function mutations in genes encoding RAS signaling elements. Finally, we show that endogenous R-RAS2, unlike the case of classical RAS proteins, specifically localizes in focal adhesions. Collectively, these results indicate that gain-of-function mutations of R-RAS2/TC21 play roles in tumor initiation and maintenance that are not fully redundant with those regulated by classical RAS oncoproteins

The complex influence of ENSO on droughts in Ecuador

48 Pags.- 1 Tabl.- 18 Figs. The definitive version is available at: http://link.springer.com/journal/382In this study, we analyzed the influence of El Niño–Southern Oscillation (ENSO) on the spatio-temporal variability of droughts in Ecuador for a 48-year period (1965–2012). Droughts were quantified from 22 high-quality and homogenized time series of precipitation and air temperature by means of the Standardized Precipitation Evapotranspiration Index. In addition, the propagation of two different ENSO indices (El Niño 3.4 and El Niño 1 + 2 indices) and other atmospheric circulation processes (e.g., vertical velocity) on different time-scales of drought severity were investigated. The results showed a very complex influence of ENSO on drought behavior across Ecuador, with two regional patterns in the evolution of droughts: (1) the Andean chain with no changes in drought severity, and (2) the Western plains with less severe and frequent droughts. We also detected that drought variability in the Andes mountains is explained by the El Niño 3.4 index [sea surface temperature (SST) anomalies in the central Pacific], whereas the Western plains are much more driven by El Niño 1 + 2 index (SST anomalies in the eastern Pacific). Moreover, it was also observed that El Niño and La Niña phases enhance droughts in the Andes and Western plains regions, respectively. The results of this work could be crucial for predicting and monitoring drought variability and intensity in Ecuador.This work was supported by the EPhysLab (UVIGO-CSIC Associated Unit) and the research projects I-COOP H2O 2013CD0006: “Test multisectorial y actividades demostrativa sobre el potencial desarrollo de sistemas de monitorización de sequías en tiempo real en la región del oeste de Sudamérica” financed by the Spanish National Research Council, CGL2011-27574-CO2-02, CGL2014-52135-C03-01 and Red de variabilidad y cambio climático RECLIM (CGL2014-517221-REDT), financed by the Spanish Commission of Science and Technology and FEDER, and “LIFE12 ENV/ES/000536-Demonstration and validation of innovative methodology for regional climate change adaptation in the Mediterranean area (LIFE MEDACC)” financed by the LIFE programme of the European Commission. Cesar Azorin-Molina was supported by the JCI-2011-10263 Grant. Arturo Sanchez-Lorenzo was supported by the JCI-2012-12508 Grant. Miquel Tomas-Burguera was supported by a doctoral grant by the Ministry of Economy and Competitiveness and Natalia Martin-Hernandez was supported by a doctoral grant by the Aragón Regional Government. E. Aguilar was funded by the Grant CCI-009-ATN/OC-12439-RG-2012 from the Banco Iberoamericano de Desarrollo.Peer reviewe