10,719 research outputs found

    What is a scientific experiment?: The impact of a professional development course on teachers’ ability to design an inquiry-based science curriculum

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    Designing inquiry-based science lessons can be a challenge for secondary school teachers. In this study we evaluated the development of in-service teachers’ lesson plans as they took part in a 10-month professional development course in Peru which engaged teachers in the design of inquiry-based lessons. At the beginning, most teachers designed either confirmatory or structured inquiry activities. As the course progressed, however, they started designing guided and open inquiry lesson plans. We found four factors that accounted for this change: re-evaluating the need for lab materials, revising their views on the nature of science, engaging in guided and open inquiry activities themselves, and trying out inquiry-based lessons with their own students. Our results point to the importance of engaging teachers in prolonged and varied opportunities for inquiry as part of teacher education programs in order to achieve the challenge of changing teachers’ views and practices in science education.Fil: Pérez, María del Carmen B.. Universidad de Piura; PerúFil: Furman, Melina Gabriela. Universidad de San Andrés. Escuela de Educación; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

    El reto de vincular reputación online de destinos turísticos con competitividad

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    The aim of this study is to evidence how 2.0 conversations in social media impact the reputation of destinations. Additionally, the influence of co-creation practices is analysed. The five most competitive destinations worldwide have been chosen for the research. This paper demonstrates that monitoring social media is a challenge in tourism and is a strategic tool to support process decision making and for destination brand building in a sustainable way. Currently, there are several monitoring and analytic tools, but there is a lack of models to systematise and harness it for the Destination Management Organization (DMOs). In conclusion, how tourists play the main role in the competitiveness of Destinations with their experiences and opinions are considered, along with some keys for successful management of social media are given in the view of the results.info:eu-repo/semantics/publishedVersio

    Short-term growth and biomechanical responses of the temperate seagrass Cymodocea nodosa to CO2 enrichment

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    Seagrasses are often regarded as climate change 'winners' because they exhibit higher rates of photosynthesis, carbon fixation and growth when exposed to increasing levels of ocean acidification. However, questions remain whether such growth enhancement compromises the biomechanical properties of the plants, altering their vulnerability to structural damage and leaf loss. Here, we investigated the short-term (6 wk) effects of decreasing pH by CO2 enrichment on the growth, morphology and leaf-breaking force of the temperate seagrass Cymodocea nodosa. We found that the plant biomass balance under levels of acidification representative of short-term climate change projections (pH 8.04) was positive and led to an increase in leaf abundance in the shoots. However, we also found that plant biomass balance was negative under levels of acidification experienced presently (pH 8.29) and those projected over the long-term (pH 7.82). Leaf morphology (mean leaf length, thickness and width) was invariant across our imposed acidification gradient, although leaves were slightly stronger under [CO2] representative of short-term climate change. Taken together, these findings indicate that a subtle increase in growth and mechanical resistance of C. nodosa is likely to occur following short-to medium-term changes in ocean chemistry, but that these positive effects are unlikely to be maintained over the longer term. Our study emphasises the need to account for the interdependencies between environmental conditions and variations in multiple aspects of the structure and functioning of seagrass communities when considering the likely consequences of climate change.Mobility Fellowships Programme of the EuroMarine Consortium (European Commission Seventh Framework Programme) [FP7-ENV-2010.2.2.1-3]; Foundation of Science and Technology of Portugal [SFRH/BPD/119344/2016, PTDC/MAR-EST/3223/2014]; Natural Environment Research Council (NERC) through the UK Ocean Acidification Research Programme (UKOARP) [NE/H017445/1]info:eu-repo/semantics/publishedVersio

    Pattern for Re-engineering a Classification Scheme, which Follows the Adjacency List Data Model, to a Taxonomy

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    This pattern for re-engineering non-ontological resources (pr-nor) fits in the schema re-engineering category proposed by [3]. The pattern defines a procedure that transforms the classification scheme components into ontology representational primitives. This pattern comes from the experience of ontology engineers in developing ontologies using classification schemes in several projects (seemp 1 , neon 2 , and knowledge web 3 ). The pattern is included in a pool of patterns, which is a key element of our method for re-engineering non-ontological resources into ontologies [2]. The patterns generate the ontologies at a conceptualization level, independent of the ontology implementation language

    Amyloid beta and diabetic pathology cooperatively stimulate cytokine expression in an Alzheimer's mouse model

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    Background Diabetes is a risk factor for developing Alzheimer's disease (AD); however, the mechanism by which diabetes can promote AD pathology remains unknown. Diabetes results in diverse molecular changes in the brain, including dysregulation of glucose metabolism and loss of cerebrovascular homeostasis. Although these changes have been associated with increased A beta pathology and increased expression of glial activation markers in APPswe/PS1dE9 (APP/PS1) mice, there has been limited characterization, to date, of the neuroinflammatory changes associated with diabetic conditions. Methods To more fully elucidate neuroinflammatory changes associated with diabetes that may drive AD pathology, we combined the APP/PS1 mouse model with either high-fat diet (HFD, a model of pre-diabetes), the genetic db/db model of type 2 diabetes, or the streptozotocin (STZ) model of type 1 diabetes. We then used a multiplexed immunoassay to quantify cortical changes in cytokine proteins. Results Our analysis revealed that pathology associated with either db/db, HFD, or STZ models yielded upregulation of a broad profile of cytokines, including chemokines (e.g., MIP-1 alpha, MIP-1 beta, and MCP-1) and pro-inflammatory cytokines, including IL-1 alpha, IFN-gamma, and IL-3. Moreover, multivariate partial least squares regression analysis showed that combined diabetic-APP/PS1 models yielded cooperatively enhanced expression of the cytokine profile associated with each diabetic model alone. Finally, in APP/PS1xdb/db mice, we found that circulating levels of A beta 1-40, A beta 1-42, glucose, and insulin all correlated with cytokine expression in the brain, suggesting a strong relationship between peripheral changes and brain pathology. Conclusions Altogether, our multiplexed analysis of cytokines shows that Alzheimer's and diabetic pathologies cooperate to enhance profiles of cytokines reported to be involved in both diseases. Moreover, since many of the identified cytokines promote neuronal injury, A beta and tau pathology, and breakdown of the blood-brain barrier, our data suggest that neuroinflammation may mediate the effects of diabetes on AD pathogenesis. Therefore, strategies targeting neuroinflammatory signaling, as well as metabolic control, may provide a promising strategy for intervening in the development of diabetes-associated AD

    Vibrations of free and embedded anisotropic elastic spheres: Application to low-frequency Raman scattering of silicon nanoparticles in silica

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    Vibrational mode frequencies and damping are calculated for an elastic sphere embedded in an infinite, homogeneous, isotropic elastic medium. Anisotropic elasticity of the sphere significantly shifts the frequencies in comparison to simplified calculations that assume isotropy. New low frequency Raman light scattering data are presented for silicon spheres grown in a SiO2 glass matrix. Principal features of the Raman spectrum are not correctly described by a simple model of the nanoparticle as a free, isotropic sphere, but require both matrix effects and the anisotropy of the silicon to be taken into account. Libration, not vibration, is the dominant mechanism

    Embedding Population Dynamics Models in Inference

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    Increasing pressures on the environment are generating an ever-increasing need to manage animal and plant populations sustainably, and to protect and rebuild endangered populations. Effective management requires reliable mathematical models, so that the effects of management action can be predicted, and the uncertainty in these predictions quantified. These models must be able to predict the response of populations to anthropogenic change, while handling the major sources of uncertainty. We describe a simple ``building block'' approach to formulating discrete-time models. We show how to estimate the parameters of such models from time series of data, and how to quantify uncertainty in those estimates and in numbers of individuals of different types in populations, using computer-intensive Bayesian methods. We also discuss advantages and pitfalls of the approach, and give an example using the British grey seal population.Comment: Published at http://dx.doi.org/10.1214/088342306000000673 in the Statistical Science (http://www.imstat.org/sts/) by the Institute of Mathematical Statistics (http://www.imstat.org

    Transport on a Lattice with Dynamical Defects

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    Many transport processes in nature take place on substrates, often considered as unidimensional lanes. These unidimensional substrates are typically non-static: affected by a fluctuating environment, they can undergo conformational changes. This is particularly true in biological cells, where the state of the substrate is often coupled to the active motion of macromolecular complexes, such as motor proteins on microtubules or ribosomes on mRNAs, causing new interesting phenomena. Inspired by biological processes such as protein synthesis by ribosomes and motor protein transport, we introduce the concept of localized dynamical sites coupled to a driven lattice gas dynamics. We investigate the phenomenology of transport in the presence of dynamical defects and find a novel regime characterized by an intermittent current and subject to severe finite-size effects. Our results demonstrate the impact of the regulatory role of the dynamical defects in transport, not only in biology but also in more general contexts

    Aplicación de índices de tolerancia a la salinidad en plántulas de maíz

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    Los objetivos de este trabajo fueron: estudiar la aplicación de diferentes índices de tolerancia en caracteres de plántulas de maíz y evaluar su posible utilidad en la identificación de genotipos tolerantes a la salinidad. Se probaron 68 accesiones en dos ambientes (0 y 100m MClNa). Se midieron: largo de raíz, vástago y 3ª hoja y peso seco de raíz y de parte aérea. Se incluyeron 6 índices de tolerancia: índice de susceptibilidad al estrés (SSI), índice de tolerancia al estrés (STI), tolerancia al estrés (TOL), media geométrica de la productividad (GMP), productividad media (MP) e índice de estabilidad del rendimiento (YSI). Debido a la variación espacial relacionada con la concentración de sal en ambientes salinos, sería importante identificar genotipos estables frente a una gama amplia de suelos salinos. El biplot agrupó las accesiones, caracteres medidos en ambientes con y sin estrés e índices de tolerancia a sal, y demostró que los índices GMP, MP y STI fueron los que permitieron identificar los accesiones estables que se caracterizan por tener una alta expresión de estos caracteres en ambos ambientes. La aplicación del método de Componentes Principales (CP) identificó a los caracteres peso seco aéreo y largo de raíz como los de mayor contribución y ambos estuvieron asociados con dichos indices de tolerancia a salinidad. De esta manera, en este estudio las accesiones 1, 7, 30, 33, 43 y 45 fueron los más estables para los caracteres peso seco aéreo y largo de raíz. Entre ellos las accesiones 30 y 33 fueron superiores (pertenecientes a genotipos del Grupo A) porque mostraron los escores más altos sobre el eje CP1 pero sus aportes al CP2 fueron bastantes pequeños, para la mayoría de las variables.The aims of this research were: to study the application of different tolerance Indices in traits measured in maize seedlings and to assess their possible use in the identification of genotypes tolerant to salinity. Sixty eight accessions were tested in two environments (0 and 100mM NaCl). We recorded length for radicle, shoot and third leaf and dry weight for root and shoot. Six stress tolerance indices were included: stress susceptibility (SSI), stress tolerance index (STI), stress tolerance (TOL), geometric mean productivity (GMP), mean productivity (MP) and yield stability index (YSI. Saline environments show a great spatial variation in relation to the salt concentration, for this reason it would be important to identify genotypes with stable behavior in a variety of saline soils. The biplot method allowed clustering accessions, traits measured in stress and non stress environment and salt tolerance Indexes in a same graphic, and showed that GMP, MP and STI indexes were the ones who helped identify the high yielding (group A genotype) and stable accessions, characterized by a high expression of these characters in both environments. Principal Component method showed that shoot dry weight and root length had the highest contribution and both were associated with these above indices in salinity. Therefore, in this study the accessions: 1, 7, 30, 33, 43 and 45 had stable values for the traits root length and shoot dry weight. Within this group the 30 and 33 entries were superior (bellowing to Group A genotypes) because they had the highest PC1 scores but its PC2 scores were rather small for the most of the variables.Fil: Collado, Mónica B.. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Instituto Fitotécnico de "Santa Catalina"; ArgentinaFil: Aulicino, Mónica Beatriz. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Instituto Fitotécnico de "Santa Catalina"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Arturi, Miguel Jacinto. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Instituto Fitotécnico de "Santa Catalina"; ArgentinaFil: Molina, María del Carmen. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Instituto Fitotécnico de "Santa Catalina"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
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