936 research outputs found
Nuevas orientaciones en la formación del profesorado para una enseñanza centrada en la promoción del aprendizaje autorregulado de los alumnos
La sociedad del conocimiento demanda una alta capacitación en
los alumnos para aprender a aprender y, en consecuencia, un
modelo de enseñanza más centrado en el mismo proceso de
aprendizaje (learning-centered teaching). En este artículo se trata de
explicar que este paradigma exige un profesor que actúe como
guía en el proceso de aprendizaje y asuma la postura de
“experto-aprendiz” en el aula. Para ello es necesaria una
formación docente más acorde con los principios actuales del
aprendizaje puesto que, de este modo el profesor estará más
capacitado para desempeñar su cambio de rol
Evaluation of the MODIS Albedo Product over a Heterogeneous Agricultural Area
In this article, the Moderate Resolution Imaging Spectroradiometer (MODIS) Bidirectional Reflectance Distribution Function (BRDF)/Albedo product (MCD43) is evaluated over a heterogeneous agricultural area in the framework of the Earth Observation: Optical Data Calibration and Information Extraction (EODIX) project campaign, which was developed in Barrax (Spain) in June 2011. In this method, two models, the RossThick-LiSparse-Reciprocal (RTLSR) (which corresponds to the MODIS BRDF algorithm) and the RossThick-Maignan-LiSparse-Reciprocal (RTLSR-HS), were tested over airborne data by processing high-resolution images acquired with the Airborne Hyperspectral Scanner (AHS) sensor. During the campaign, airborne images were retrieved with different view zenith angles along the principal and orthogonal planes. Comparing the results of applying the models to the airborne data with ground measurements, we obtained a root mean square error (RMSE) of 0.018 with both RTLSR and RTLSR-HS models. The evaluation of the MODIS BRDF/Albedo product (MCD43) was performed by comparing satellite images with AHS estimations. The results reported an RMSE of 0.04 with both models. Additionally, taking advantage of a homogeneous barley pixel, we compared in situ albedo data to satellite albedo data. In this case, the MODIS albedo estimation was (0.210 +/- 0.003), while the in situ measurement was (0.204 +/- 0.003). This result shows good agreement in regard to a homogeneous pixel
Data Privacy Concerns as a Source of Resistance to Complete Mobile Data Collection Tasks Via a Smartphone App
Smartphones present many interesting opportunities for survey research, particularly through the use of mobile data collection applications (apps). There is still much to learn, however, about how to integrate apps in general population surveys. Recent studies investigating hypothetical willingness to complete mobile data collection tasks via an app suggest there may be substantial resistance, in particular, due to concerns around data privacy. There is not much evidence about how privacy concerns influence actual decisions to participate in app-based surveys. Theoretical approaches to understanding privacy concerns and survey participation decisions would suggest that the influence of the former over the latter is likely to vary situationally. In this paper, we present results from a methodological experiment conducted in the context of a three-wave probability-based online panel survey of the general population as part of the 2019 Swiss Election Study ("Selects") testing different ways of recruiting participants to an app. Questions included at wave 1 about online data privacy concerns and comfort sharing different types of data with academic researchers allow us to assess their impact on both hypothetical willingness to download a survey app for completing questionnaires, to take and share photos, and to share the smartphone's GPS location and actual completion of these tasks. Our findings confirm that general concerns about online data privacy do influence hypothetical willingness to complete mobile data collection tasks, but may be overridden by how comfortable people feel about sharing specific types of data with researchers. When it comes to actual compliance with task requests, however, neither privacy concerns nor comfort sharing data seem to matter. We conclude with recommendations for exploring these relationships further in future app-based studies
The Early Oxidative Stress Induced by Mercury and Cadmium Is Modulated by Ethylene in Medicago sativa Seedlings
Cadmium (Cd) and mercury (Hg) are ubiquitous soil pollutants that promote the accumulation of reactive oxygen species, causing oxidative stress. Tolerance depends on signalling processes that activate different defence barriers, such as accumulation of small heat sock proteins (sHSPs), activation of antioxidant enzymes, and the synthesis of phytochelatins (PCs) from the fundamental antioxidant peptide glutathione (GSH), which is probably modulated by ethylene. We studied the early responses of alfalfa seedlings after short exposure (3, 6, and 24 h) to moderate to severe concentration of Cd and Hg (ranging from 3 to 30 μM), to characterize in detail several oxidative stress parameters and biothiol (i.e., GSH and PCs) accumulation, in combination with the ethylene signalling blocker 1-methylcyclopropene (1-MCP). Most changes occurred in roots of alfalfa, with strong induction of cellular oxidative stress, H2O2 generation, and a quick accumulation of sHSPs 17.6 and 17.7. Mercury caused the specific inhibition of glutathione reductase activity, while both metals led to the accumulation of PCs. These responses were attenuated in seedlings incubated with 1-MCP. Interestingly, 1-MCP also decreased the amount of PCs and homophytochelatins generated under metal stress, implying that the overall early response to metals was controlled at least partially by ethylen
Microglial activation arises after aggregation of phosphorylated-tau in a neuron-specific P301S tauopathy mouse model
Alzheimer's disease, progressive supranuclear palsy and frontotemporal dementia are characterized by neuronal expression of aberrant tau protein, tau hyperphosphorylation (pTAU), tau aggregation and neurofibrillary tangle formation sequentially culminating into neuronal cell death, a process termed tauopathy. Our aim was to address at which tauopathy stage neuroinflammation starts and to study the related microglial phenotype. We used Thy1-hTau.P301S (PS) mice expressing human tau with a P301S mutation specifically in neurons. Significant levels of cortical pTAU were present from 2 months onwards. Dystrophic morphological complexity of cortical microglia arose after pTAU accumulation concomitant with increased microglial lysosomal volumes and a significant loss of homeostatic marker Tmem119. Interestingly, we detected increases in neuronal pTAU and postsynaptic structures in the lysosomes of PS microglia. Moreover, the overall cortical postsynaptic density was decreased in 6-month-old PS mice. Together, our results indicate that microglia adopt a pTAU-associated phenotype, and are morphologically and functionally distinct from wild-type microglia after neuronal pTAU accumulation has initiated
The nursery role of the Guadalquivir estuary for marine fish. A long-term ecological research
Trabajo presentado en el 23rd Biennial CERF Conference (Grand challenges in coastal and Estuarine Science: securin our future), celebrado en Portland (Oregón, US) del 8 al 12 de noviembre de 2015.N
Detección de estrés hídrico en olivar mediante datos hiperespectrales y térmicos del sensor AHS
El sensor hiperespectral AHS (Airborrne Hyperspectal
Scanner) fue utilizado para obtener imágenes
de 2.5 m de resolución espacial en el espectro visible,
infrarrojo cercano y térmico en una parcela de olivar
en Córdoba (España) con el fin de estudiar la variabilidad
espacial y temporal del estrés hídrico. Los datos
térmicos del AHS permitieron obtener imágenes de
temperatura de superficie de la parcela a las 7:30,
9:30 y 12:30 GMT el 25 de julio de 2004. EL diseño
experimental en bloques aleatorios consistió en aplicar
tres dosis diferentes de riego durante julio, agosto
y septiembre, realizando medidas semanales de
potencial hídrico, fotosíntesis y conductancia para
estudiar los efectos del estrés hídrico en el cultivo.
Los sensores de infrarrojo IRT permitieron la realización
de medidas continuas de temperatura sobre las
copas de los árboles, facilitando la validación de las
imágenes térmicas. Los resultados de este estudio son
presentados, destacando la aplicabilidad en la agricultura
de precisión de la teledetección térmica e hiperespectral
de alta resolución espacial para el estudio
del suministro y la dosificación del riego.The Airborne Hyperspectral Scanner (AHS) was
used to acquire images with 2.5 m spatiala resolution
in the visible, near infrared and thermal spectral
regions over an olive orchard in Cordoba (Spain) to
study the spatial and temporal variability of water
stress. The AHS thermal information enabled obtaining
surface temperature images of the orchard at
7:30, 9:30 and 12:30 GMT in 25 july 2004. The
experimental design consisted of applying three different
irrigation treatments in randomly selected
blocks during july, august and septemper, acquiring
measurements of leaf water potential, stomatal conductance
and photosynthesis to study the water stress
effects on the trees. Infrared sensors IRT placed on
top of the trees allowed to obtain continuously temperature
measurements, providing validation data for
the airborne thermal imagery. Results of this study
are presented, suggesting that hyperspectral and high
resolution remote sensing methods have important
applicability in precision agriculture for management
of controlled deficit irrigation method
Modelling the effect of environmental and anthropogenic factors on the abundance of early life-history stages of the European sardine in the Guadalquivir estuary
Estuarine coastal areas play an important role in the recruitment of some small pelagic sh populations mainly when stable salinity-gradients are present. Damming of these ecosystems results in major alterations in this natural hydrological regime. Therefore, changes in the marine/freshwater balance can result in services loss, like the nursery habitat estuaries provide to small pelagic sh, such as sardines. Our previous work showed that the main important recruitment of sardine occurs in spring when this water balance is more variable. However, the drivers of sardine recruitment and particularly the interactive effects of environmental (temperature, salinity, turbidity and winds) and anthropogenic (freshwater discharges) factors are largely unknown. We modelled these effects on the abundance of sardine larvae and juveniles in the Guadalquivir estuary, the most southwestern one in the Atlantic Europe. Sardine early stages tend to occur at the most seaward and more saline sampling site in our study area. The best selected models included the freshwater ow and the wind regimen (northern-southern component) as main drivers explaining their abundance. Freshwater input –tightly controlled by a dam– had a negative short-term effect on the abundance of juvenile sardines above a critical threshold. On top of this, the wind-speed variability in the northern-southern direction showed a clear linear effect: with strong northerly winds enhancing the sardine abundance in the Guadalquivir estuary. These results contribute to the knowledge of the recruitment process of the European sardine and eventually to implementing an ecosystem approach to its fishery in the Gulf of Cadiz
proMetalloproteinase-10 is associated with brain damage and clinical outcome in acute ischemic stroke
BACKGROUND: Matrix metalloproteinases (MMPs) mediate tissue injury during stroke but also neurovascular remodeling and we have shown that MMP-10 is involved in atherothrombosis. OBJECTIVE: The purpose of this study was to examine the relationship between proMMP-10 and clinical outcome, assessing inflammatory and proteolytic markers, in patients with acute ischemic stroke. METHODS: We prospectively studied 76 patients with ischemic stroke treated with tPA within the first 3 h from symptom onset, compared with 202 non-tPA-treated ischemic stroke patients and 83 asymptomatic subjects. Stroke severity was assessed with the National Institutes of Health Stroke Scale (NIHSS). Hemorrhagic transformation (HT) and severe brain edema were diagnosed by cranial CT. Good functional outcome was defined as a modified Rankin scale score </= 2 at 90 days. Serum levels of MMP-9, proMMP-10, TIMP-1, tumor necrosis factor-alpha (TNFalpha), interleukin-6 and cellular fibronectin were measured at admission. The effect of TNFalpha on endothelial proMMP-10 was assessed in vitro. RESULTS: Serum proMMP-10 concentration in ischemic stroke patients, non-treated or treated with t-PA, which was higher than age-matched healthy subjects (P < 0.0001), was independently associated with higher infarct volume, severe brain edema, neurological deterioration and poor functional outcome at 3 months (all P < 0.05), but not with HT. proMMP-10 levels were also independently and positively associated with circulating levels of TNFalpha (P < 0.0001), which induced its endothelial expression in vitro, both mRNA and protein. MMP-9, however, was only associated with HT and severe edema (all P < 0.05). CONCLUSIONS: Increased serum proMMP-10 after acute ischemic stroke, associated with TNFalpha, is a new marker of brain damage and poor outcome
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