2,581 research outputs found
Evaluating tag-based information access in image collections
The availability of social tags has greatly enhanced access to information. Tag clouds have emerged as a new "social" way to find and visualize information, providing both one-click access to information and a snapshot of the "aboutness" of a tagged collection. A range of research projects explored and compared different tag artifacts for information access ranging from regular tag clouds to tag hierarchies. At the same time, there is a lack of user studies that compare the effectiveness of different types of tag-based browsing interfaces from the users point of view. This paper contributes to the research on tag-based information access by presenting a controlled user study that compared three types of tag-based interfaces on two recognized types of search tasks - lookup and exploratory search. Our results demonstrate that tag-based browsing interfaces significantly outperform traditional search interfaces in both performance and user satisfaction. At the same time, the differences between the two types of tag-based browsing interfaces explored in our study are not as clear. Copyright 2012 ACM
GluR1 links structural and functional plasticity at excitatory synapses
Long-term potentiation (LTP), a cellular model of learning and memory, produces both an enhancement of synaptic function and an increase in the size of the associated dendritic spine. Synaptic insertion of AMPA receptors is known to play an important role in mediating the increase in synaptic strength during LTP, whereas the role of AMPA receptor trafficking in structural changes remains unexplored. Here, we examine how the cell maintains the correlation between spine size and synapse strength during LTP. We found that cells exploit an elegant solution by linking both processes to a single molecule: the AMPA-type glutamate receptor subunit 1 (GluR1). Synaptic insertion of GluR1 is required to permit a stable increase in spine size, both in hippocampal slice cultures and in vivo. Synaptic insertion of GluR1 is not sufficient to drive structural plasticity. Although crucial to the expression of LTP, the ion channel function of GluR1 is not required for the LTP-driven spine size enhancement. Remarkably, a recombinant cytosolic C-terminal fragment (C-tail) of GluR1 is driven to the postsynaptic density after an LTP stimulus, and the synaptic incorporation of this isolated GluR1 C-tail is sufficient to permit spine enlargement even when postsynaptic exocytosis of endogenous GluR1 is blocked. We conclude that during plasticity, synaptic insertion of GluR1 has two functions: the established role of increasing synaptic strength via its ligand-gated ion channel, and a novel role through the structurally stabilizing effect of its C terminus that permits an increase in spine size
Influence of Olive Oil Mill Waste Amendment on Fate of Oxyfluorfen in Southern Spain Soils
7 páginas.-- 1 figura.-- 3 tablas.-- 37 referencias.--Oxyfluorfen herbicide residues have been previously reported in surface and ground water in the Guadalquivir river basin in Spain. Soil factors and processes (sorption, dissipation, and leaching) influencing the potential offsite transport of oxyfluorfen to surface and ground water were characterized in laboratory experiments for two soils from Southern Spain. The influence of olive-oil mill waste amendment on the soil processes was also determined. Oxyfluorfen sorption in unamended soils was not significantly affected by soil active components (organic matter and clay fraction). However, a significant increase in soil sorption of the herbicide was observed upon amendment. Laboratory half-life values for oxyfluorfen in unamended sandy clay loam and silty clay soils at 40% moisture content and 25°C were 29 and 19 days, respectively, and it increased by a factor of four upon amendment. Oxyfluorfen's mobility along soil profile increased with the amendment in leaching studies at 25°C, suggesting that dissolved organic matter of amendment can play an important role enhancing soil vertical movement of the pesticide. The increase in soil adsorption and persistence observed with olive-oil mill waste amendment can promote its losses by runoff following winter application, whereas vertical movement of oxyfluorfen can be enhanced following spring application when olive-oil mill waste amendment is also applied.This work has been partially financed by research projects P06-AGR-565, P07-AGR-03077, and AGR-264 from Junta de Andalucia, all of them cofinanced with EU FEDER-FSE funds (Operative Program 2003/06 and 2007/11). This work has been specially supported by I-Link 0025 research project from CSIC. We are grateful to Dow Agrosciences LLC, Indianapolis, IN for supplying 14C-labeled oxyfluorfen. Authors also thank to Dra. L. Cox and Dr. R. Celis for manuscript valuable support, comments and suggestions.Peer reviewe
Circulating Retinol-Binding Protein-4 Concentration Might Reflect Insulin Resistance–Associated Iron Overload
OBJECTIVES—The mechanisms behind the association between retinol-binding protein-4 (RBP4) and insulin resistance are not well understood. An interaction between iron and vitamin A status, of which RBP4 is a surrogate, has long been recognized. We hypothesized that iron-associated insulin resistance could be behind the impaired insulin action caused by RBP4
Updating known distribution models for forecasting climate change impact on endangered species
To plan endangered species conservation and to design adequate management programmes, it is necessary to predict their
distributional response to climate change, especially under the current situation of rapid change. However, these
predictions are customarily done by relating de novo the distribution of the species with climatic conditions with no regard
of previously available knowledge about the factors affecting the species distribution. We propose to take advantage of
known species distribution models, but proceeding to update them with the variables yielded by climatic models before
projecting them to the future. To exemplify our proposal, the availability of suitable habitat across Spain for the endangered
Bonelli’s Eagle (Aquila fasciata) was modelled by updating a pre-existing model based on current climate and topography to
a combination of different general circulation models and Special Report on Emissions Scenarios. Our results suggested that
the main threat for this endangered species would not be climate change, since all forecasting models show that its
distribution will be maintained and increased in mainland Spain for all the XXI century. We remark on the importance of
linking conservation biology with distribution modelling by updating existing models, frequently available for endangered
species, considering all the known factors conditioning the species’ distribution, instead of building new models that are
based on climate change variables only.Ministerio de Ciencia e Innovación and FEDER (project CGL2009-11316/BOS
Surfactant Protein D, a Marker of Lung Innate Immunity, Is Positively Associated With Insulin Sensitivity
Impaired lung function and innate immunity have both attracted growing interest as a potentially novel risk factor for glucose intolerance, insulin resistance, and type 2 diabetes. We aimed to evaluate whether surfactant protein D (SP-D), a lung-derived innate immune protein, was behind these associations
Directional kernel density estimation for classification of breast tissue spectra
In Breast Conserving Therapy, surgeons measure the thickness of healthy tissue surrounding an excised tumor (surgical margin) via post-operative histological or visual assessment tests that, for lack of enough standardization and reliability, have recurrence rates in the order of 33%. Spectroscopic interrogation of these margins is possible during surgery, but algorithms are needed for parametric or dimension reduction processing. One methodology for tumor discrimination based on dimensionality reduction and nonparametric estimation - in particular, Directional Kernel Density Estimation - is proposed and tested on spectral image data from breast samples. Once a hyperspectral image of the tumor has been captured, a surgeon assists by establishing Regions of Interest where tissues are qualitatively differentiable. After proper normalization, Directional KDE is used to estimate the likelihood of every pixel in the image belonging to each specified tissue class. This information is enough to yield, in almost real time and with 98% accuracy, results that coincide with those provided by histological H&E validation performed after the surgery.Research reported in this paper was funded by projects DA2TOI (codename FIS 2010-19860), FOS4 (codename TEC 2013-47264-C2-1-R) and an undergraduate Research Assistant Fellowship (Beca de Colaboración) entitled “Multispectralenhancement systems for tissue diagnosis in oncology and cardiovascularmedicine,” the latter granted to themain author by the SpanishMinistry of Education, Culture and Sports
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