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BACKGROUND The average accepted depth for Non-Tunneled Catheters (NTC) insertion does not guarantee its correct position, so controversy exists. The aim is to assess the effect of two NTC placement depths on the number of NTC complication episodes. METHODS We designed a triple blind, parallel-group, randomized controlled trial in a single Hemodialysis Center in Mexico (Registry: ACTRN12619000774123). We included patients in urgent need of hemodialysis via internal right jugular vein NTC. The length of the NTC tip placement depth was randomized to second intercostal space (2ICS) or fourth intercostal space (4ICS), using physical landmarks. The primary outcome is to compare the composite number of NTC dysfunction, repositioning, and relocation episodes during 48 hours post procedure. RESULTS One hundred and sixty five patients were included, 86 and 79 patients to NTC placement in the 2ICS and 4ICS, respectively. All patients underwent intention-to treat analysis. The incidence of the composite outcome was lower in the 2ICS group compared to the 4ICS group, 4 (4.6%) and 50 (63%) combined episodes, respectively (p

From simple averaging to more sophisticated registration and restoration strategies, such as super-resolution (SR), there exist different computational techniques that use a series of images of the same object to generate enhanced images where noise and other distortions have been reduced. In this work, we provide qualitative and quantitative measurements of this enhancement for high-angle annular dark-field scanning transmission electron microscopy imaging. These images are compared in two ways, qualitatively through visual inspection in real and reciprocal space, and quantitatively, through the calculation of objective measurements, such as signal-to-noise ratio and atom column roundness. Results show that these techniques improve the quality of the images. In this paper, we use an SR methodology that allows us to take advantage of the information present in the image frames and to reliably facilitate the analysis of more difficult regions of interest in experimental images, such as surfaces and interfaces. By acquiring a series of cross-sectional experimental images of magnetite (Fe3O4) thin films (111), we have generated interpolated images using averaging and SR, and reconstructed the atomic structure of the very top surface layer that consists of a full monolayer of Fe, with topmost Fe atoms in tetrahedrally coordinated sites.

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14 pages, 4 figures, 1 table.-- This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY), To study the response of bacteria to different size-fractions of naturally occurring dissolved organic matter (DOM), a natural prokaryotic community from North Atlantic mesopelagic waters (1000 m depth) was isolated and grown in (i) 0.1-μm filtered seawater (CONTROL), (ii) the low-molecular-weight (1 kDa) and low-molecular-weight DOM fractions (H + L-DOM), to test the potential effect of ultrafiltration on breaking the DOM size continuum. Prokaryotic abundance and leucine incorporation were consistently higher in the H + L-DOM niche than in the L-DOM and CONTROL treatments, suggesting a different interaction with each DOM fraction and the disruption of the structural DOM continuum by ultrafiltration, respectively. Rhodobacterales (Alphaproteobacteria) and Flavobacteriales (Bacteroidetes) were particularly enriched in L-DOM and closely related to the colored DOM (CDOM) fraction, indicating the tight link between these groups and changes in DOM aromaticity. Conversely, some other taxa that were rare or undetectable in the original bacterial community were enriched in the H + L-DOM treatment (e.g., Alteromonadales belonging to Gammaproteobacteria), highlighting the role of the rare biosphere as a seed bank of diversity against ecosystem disturbance. The relationship between the fluorescence of protein-like CDOM and community composition of populations in the H + L-DOM treatment suggested their preference for labile DOM. Conversely, the communities growing on the L-DOM niche were coupled to humic-like CDOM, which may indicate their ability to degrade more reworked DOM and/or the generation of refractory substrates (as by-products of the respiration processes). Most importantly, L- and/or H + L-DOM treatments stimulated the growth of unique bacterial amplicon sequence variants (ASVs), suggesting the potential of environmental selection (i.e., changes in DOM composition and availability), particularly in the light of climate change scenarios. Taken together, our results suggest that different size-fractions of DOM induced niche-specialization and differentiation of mesopelagic bacterial communities, Funding for sampling and analyses was supported by the projects “Biodiversidade Funcional do Microplancton nas profundidades mariñas de Galicia” (BIO-PROF, Ref. 10MMA604024PR, 2010–2012, Xunta de Galicia), “Fuentes de Materia Orgánica y Diversidad Funcional del Microplancton en las aguas profundas del Atlántico Norte” (MODUPLAN, Ref. CTM 2011-24008, 2012–2015, Plan Nacional I + D + I; https://moduplansarmiento2014.wordpress.com/) to MMV, and “Deep Standard Oceanographic Sections monitoring program RADIALES-PRODUNDOS”, funded by the Instituto Español de Oceanografía (IEO). Additional funding was provided by the Axencia Galega de Innovación (GAIN, Xunta de Galicia) through IEO-GAIN Programme Contracts (Contratos Programa). TR-R was supported by MICINN program “Personal Técnico de Apoyo a la Investigación” (PTA, Ref. PTA2015-10948-I). MN-C was funded by the projects HOTMIX and FERMIO (MINECO, CTM2011–30010–C02–MAR and CTM2014-57334-JIN, respectively), both co-financed with FEDER funds. EG-F was supported by the BIO-PROF and MODUPLAN projects

The influence of the neighbouring atomic-columns in determining the composition at atomic column scale of quaternary semiconductor compounds, using simulated HAADF-STEM images is evaluated. The InAlAsSb alloy, a promising material in the photovoltaic field, is considered. We find that the so called 'crosstalk' effect plays an important role for the aimed compositional determination. The intensity transfer is larger from neighbouring atomic columns with higher average Z, and towards atomic columns with smaller Z. Our results show that in order to obtain precise information on the column composition, the HAADF-STEM intensities of both columns need to be taken into account simultaneously.

During image acquisition of crystalline materials by high-resolution scanning transmission electron microscopy, the sample drift could lead to distortions and shears that hinder their quantitative analysis and characterization. In order to measure and correct this effect, several authors have proposed different methodologies making use of series of images. In this work, we introduce a methodology to determine the drift angle via Fourier analysis by using a single image based on the measurements between the angles of the second Fourier harmonics in different quadrants. Two different approaches, that are independent of the angle of acquisition of the image, are evaluated. In addition, our results demonstrate that the determination of the drift angle is more accurate by using the measurements of non-consecutive quadrants when the angle of acquisition is an odd multiple of 45°.

The Cuban family medicine model has been developed, for more than three decades, as the third model of medical care of the revolutionary period in Cuba. It is the complete expression of the application of the primary health care strategy. However, it is still possible to improve the organization, quality and efficiency of health services in the first level of health care. The objective of this article is to describe the model, its singularities, distinctive elements, main achievements, and challenges. A documentary review was made from journal articles, books and official documents of the Ministry of Public Health of Cuba on the creation and development of the model; documents were selected and analyzed by experts for the preparation of this report. Conceptual elements of the model are presented, as well as indicators supporting the information. The main characteristics of family medicine in Cuba, its fundamental achievements, and challenges are presented. Based on its results, Cuba's family medicine model is a reference for the Region of the Americas. It is still a model in development, however, perfectible and susceptible to transformations to face new challenges, more importantly to renew the model keeping and strengthening the foundational ideas of the program.

Bulk dark dissolved inorganic carbon (DIC) fixation rates were determined and compared to microbial heterotrophic production in subsurface, meso- and bathypelagic Atlantic waters off the Galician coast (NW Iberian margin). DIC fixation rates were slightly higher than heterotrophic production throughout the water column, however, more prominently in the bathypelagic waters. Microautoradiography combined with catalyzed reporter deposition fluorescence in situ hybridization (MICRO-CARD-FISH) allowed us to identify several microbial groups involved in dark DIC uptake. The contribution of SAR406 (Marinimicrobia), SAR324 (Deltaproteobacteria) and Alteromonas (Gammaproteobacteria) to the dark DIC fixation was significantly higher than that of SAR202 (Chloroflexi) and Thaumarchaeota, in agreement with their contribution to microbial abundance. Q-PCR on the gene encoding for the ammonia monooxygenase subunit A (amoA) from the putatively high versus low ammonia concentration ecotypes revealed their depth-stratified distribution pattern. Taken together, our results indicate that chemoautotrophy is widespread among microbes in the dark ocean, particularly in bathypelagic waters. This chemolithoautotrophic biomass production in the dark ocean, depleted in bio-available organic matter, might play a substantial role in sustaining the dark ocean's food web.

The capability of different bacterial populations to degrade abundant polymers, such as algal-derived polysaccharides, or to utilize preferentially polymers over monomers, remains largely unknown. In this study, microautoradiography was combined with fluorescence in situ hybridization (MAR-FISH) to evaluate the ability of Bacteroidetes, SAR11, Roseobacter spp., Gammaproteobacteria and SAR86 cells to use bicarbonate, leucine and starch under natural light conditions at two locations in shelf surface waters off NW Spain. The percentage of cells incorporating bicarbonate was relatively high (mean 32% ± 4%) and was positively correlated with the intensity of solar radiation. The proportion of cells using starch (mean 56% ± 4%) or leucine (mean 47% ± 4%) was significantly higher than that using bicarbonate. On average, SAR11, Roseobacter spp. and Gammaproteobacteria showed a similarly high percentage of cells using leucine (47%-65% of hybridized cells) than using starch (51%-64% of hybridized cells), while Bacteroidetes and SAR86 cells preferentially used starch (53% of hybridized cells) over leucine (34%-40% of hybridized cells). We suggest that the great percentage of bacteria using starch is related to a high ambient availability of polymers associated to algal cell lysis, which, in turn, weakens the short-term coupling between phytoplankton release and bacterial production.

In this work, a new method to determine and correct the linear drift for any crystalline orientation in a single-column-resolved high-resolution scanning transmission electron microscopy (HR-STEM) image, which is based on angle measurements in the Fourier space, is presented. This proposal supposes a generalization and the improvement of a previous work that needs the presence of two symmetrical planes in the crystalline orientation to be applicable. Now, a mathematical derivation of the drift effect on two families of asymmetric planes in the reciprocal space is inferred. However, though it was not possible to find an analytical solution for all conditions, a simple formula was derived to calculate the drift effect that is exact for three specific rotation angles. Taking this into account, an iterative algorithm based on successive rotation/drift correction steps is devised to remove drift distortions in HR-STEM images. The procedure has been evaluated using a simulated micrograph of a monoclinic material in an orientation where all the reciprocal lattice vectors are different. The algorithm only needs four iterations to resolve a 15° drift angle in the image. Ministerio de Economía y Competitividad MAT2016-77491-C2-2-R Ministerio de Ciencia, Innovación y Universidades TEC2017-86102-C2-2-R

The goal of this research is to do a review of the online communication, taking as axis the analysis of the interactive communication characteristics in the social media versus the face-to-face conversation. The Twitter communication is an example that, similarly to the communication in presence, it is deemed conversational. In the first place, by means of the data group of cases study, this investigation will focus in examine different strategies like the retweet, the mentions (@), the hashtag function and the direct replies as resources via the users can be integrated in the conversation. Secondly, will be generally contrasted the communication properties inside to the virtual interaction frame compared the face to face conversation characteristics. Thus, this paper study how the communicative interactional resources on Twitter are established as conversational practices.

In this paper, the concept of homogeneity is defined, from a topological perspective, in order to analyze how uniform is the material composition in 2D electron microscopy images. Topological multiresolution parameters are taken into account to obtain better results than classical techniques. Ministerio de Economía y Competitividad MTM2016-81030-P Ministerio de Economía y Competitividad TEC2012-37868-C04-02

The growth of the Internet has fuelled the availability of e-commerce marketplaces and search engines must face with a huge amount of ambiguity and inconsistencies in the data. Product matching aims at disambiguating descriptions of products belonging to different websites in order to be able to recognize identical products and to merge the content from those identical items. In this work first we evaluate some similarity measures for string matching and then, we apply a complete product matching methodology to the retail market of used cars. We use a reference or master list of items and information about a wide variety of used cars offers. The resulting linkage allows energy efficiency assignment of the model identified.

Bulk dark dissolved inorganic carbon (DIC) fixation rates were determined and compared to microbial heterotrophic production in subsurface, meso- and bathypelagic Atlantic waters off the Galician coast (NW Iberian margin). DIC fixation rates were slightly higher than heterotrophic production throughout the water column, however, more prominently in the bathypelagic waters. Microautoradiography combined with catalyzed reporter deposition fluorescence in situ hybridization (MICRO-CARD-FISH) allowed us to identify several microbial groups involved in dark DIC uptake. The contribution of SAR406 (Marinimicrobia), SAR324 (Deltaproteobacteria) and Alteromonas (Gammaproteobacteria) to the dark DIC fixation was significantly higher than that of SAR202 (Chloroflexi) and Thaumarchaeota, in agreement with their contribution to microbial abundance. Q-PCR on the gene encoding for the ammonia monooxygenase subunit A (amoA) from the putatively high versus low ammonia concentration ecotypes revealed their depth-stratified distribution pattern. Taken together, our results indicate that chemoautotrophy is widespread among microbes in the dark ocean, particularly in bathypelagic waters. This chemolithoautotrophic biomass production in the dark ocean, depleted in bio-available organic matter, might play a substantial role in sustaining the dark ocean's food web.

The Cuban family medicine model has been developed, for more than three decades, as the third model of medical care of the revolutionary period in Cuba. It is the complete expression of the application of the primary health care strategy. However, it is still possible to improve the organization, quality and efficiency of health services in the first level of health care. The objective of this article is to describe the model, its singularities, distinctive elements, main achievements, and challenges. A documentary review was made from journal articles, books and official documents of the Ministry of Public Health of Cuba on the creation and development of the model; documents were selected and analyzed by experts for the preparation of this report. Conceptual elements of the model are presented, as well as indicators supporting the information. The main characteristics of family medicine in Cuba, its fundamental achievements, and challenges are presented. Based on its results, Cuba's family medicine model is a reference for the Region of the Americas. It is still a model in development, however, perfectible and susceptible to transformations to face new challenges, more importantly to renew the model keeping and strengthening the foundational ideas of the program.O modelo cubano de medicina familiar foi desenvolvido, há mais de três décadas, como o terceiro modelo de assistência médica do período revolucionário em Cuba. É a expressão mais completa da aplicação da estratégia de atenção primária à saúde. Ainda mostra potencial de melhoria na organização, qualidade e eficiência dos serviços de saúde no primeiro nível de cuidados de saúde. O objetivo essencial deste trabalho é descrever o modelo, suas singularidades, elementos distintivos, principais conquistas, e desafios. Para isso, foi feita uma revisão documental em artigos de revistas, livros e documentos oficiais do Ministério da Saúde Pública de Cuba sobre a criação e desenvolvimento do modelo, selecionados e analisados por especialistas para a elaboração deste relatório. Os elementos conceituais do modelo são apresentados, bem como indicadores que suportam a informação. Identificamos as principais características da medicina familiar em Cuba, suas conquistas fundamentais, e desafios. Com base em seus resultados, conclui-se que o modelo de medicina familiar de Cuba é uma referência para a Região das Américas. Ainda é um modelo em desenvolvimento, perfeitável e susceptível a transformações para enfrentar novos desafios, o maior dos quais será renovar o modelo com a manutenção e fortalecimento das idéias fundamentais do programa.

High-quality image reconstruction techniques allow the generation of high pixel density images from a set of low-resolution micrographs. In general, these techniques consist of two main steps, namely, accurate registration, and formulation of an appropriate forward image model via some restoration method. There exist a wide variety of algorithms to cope with both stages and depending on their practical applications, some methods can outperform others, since they can be sensitive to the assumed data model, noise, drift, etc. When dealing with images generated by Z-contrast scanning transmission electron microscopes, a current trend is based on non-rigid approximations in the registration stage. In our work we aimed at reaching similar accuracy but addressing the most complex calculations in the reconstruction stage, instead of in the registration stage (as the non-rigid approaches do), but using a much smaller number of images. We review some of the most significant methods and address their shortcomings when they are applied to the field of microscopy. Simulated images with known targets will be used to evaluate and compare the main approaches in terms of quality enhancement and computing time. In addition, a procedure to determine the reference image will be proposed to minimise the global drift on the series. The best registration and restoration strategies will be applied to experimental images in order to point up the enhanced capability of this high quality image reconstruction methodology in this field.

Product matching aims at disambiguating descriptions of products belonging to different websites in order to be able to recognize identical elements and to merge the content from those identical items. Most approaches face this matter applying various machine learning methods to textual product descriptions. Recently some authors are including information extracted from an image associated to a textual description of a product. Modern machine learning methods, such as content based information retrieval (CBIR) or deep learning, can be applied to this type of images since they can manage very large data sets for finding hidden structure within them, and for making accurate predictions. This information could boost the performance of the traditional textual matching but at the same time increase the computational complexity of the process. In this paper we review some CBIR and deep learning models and analyse the performance of these approaches when they are applied to images for product matching. The results obtained will help to introduce a combined classifier using textual and image information.

Strain mapping is defined as a numerical image-processing technique that measures the local shifts of image details around a crystal defect with respect to the ideal, defect-free, positions in the bulk. Algorithms to map elastic strains from high-resolution transmission electron microscopy (HRTEM) images may be classified into two categories: those based on the detection of peaks of intensity in real space and the Geometric Phase approach, calculated in Fourier space. In this paper, we discuss both categories and propose an alternative real space algorithm (Peak Pairs) based on the detection of pairs of intensity maxima in an affine transformed space dependent on the reference area. In spite of the fact that it is a real space approach, the Peak Pairs algorithm exhibits good behaviour at heavily distorted defect cores, e.g. interfaces and dislocations. Quantitative results are reported from experiments to determine local strain in different types of semiconductor heterostructures.

[EN] This work presents some of the results from the project: “Effect of the environment on reinforcement durability” (DURACON) in its first two-years period, which investigates the influence of urban and marine meteorochemical parameters on the performance of reinforced concrete structures. The results presented in this investigation are from 21 marine test sites only (no urban environments are included), distributed among 11 countries (Argentina, Bolivia, Brazil, Chile, Colombia, Costa Rica, Mexico, Spain, Uruguay, Portugal and Venezuela). The environment was evaluated using ISO Standard 9223 and the concrete was characterized by measuring compressive strength, elastic modulus, total and effective porosity, chloride permeability according to ASTM standards, as well as the effective porosity and resistance to water absorption using the Fagerlund method. To that effect, concrete specimens (with and without reinforcement) were prepared for electrochemical and physical/mechanical/chemical tests using the existing materials in each participating country, following strict procedures which enabled the preparation of similar concrete samples. Two water/cement (w/c) ratios (0.45 and 0.65) were selected, where the concrete with 0.45 w/c ratio had to have a minimum cement content of 400 kg/m3 and the one with 0.65 w/c ratio a compressive strength of 210 kg/cm2. Type I Portland cement, siliceous sand, and crushed rock as coarse aggregates (13-mm maximum nominal size) were used. After a one-year exposure, the results of the corrosion potentiality and probability analysis of the reinforcement in the different test stations showed that, for marine atmospheres, the most aggressive environment to induce steel corrosion was at Portugal’s Cabo Raso station, and the least aggressive one was at Chile’s Valparaíso station. These results are comparable with the ones found using electrochemical measurements, after a two-year exposure.

In this article a method for determining errors of the strain values when applying strain mapping techniques has been devised. This methodology starts with the generation of a thickness/defocus series of simulated high-resolution transmission electron microscopy images of InAsxP1−x/InP heterostructures and the application of geometric phase. To obtain optimal defocusing conditions, a comparison of different defocus values is carried out by the calculation of the strain profile standard deviations among different specimen thicknesses. Finally, based on the analogy of real state strain to a step response, a characterization of strain mapping error near an interface is proposed.

Super-resolution (SR) software-based techniques aim at generating a final image by combining several noisy frames with lower resolution from the same scene. A comparative study on high-resolution high-angle annular dark field images of InAs/GaAs QDs has been carried out in order to evaluate the performance of the SR technique. The obtained SR images present enhanced resolution and higher signal-to-noise (SNR) ratio and sharpness regarding the experimental images. In addition, SR is also applied in the field of strain analysis using digital image processing applications such as geometrical phase analysis and peak pairs analysis. The precision of the strain mappings can be improved when SR methodologies are applied to experimental images.

This paper presents a new approach to model selection based on hypothesis testing. We 4rst describe a procedure to generate di5erent scores for any candidate model from a single sample of training data and then discuss how to apply multiple comparison procedures (MCP) to model selection. MCP statistical tests allow us to compare three or more groups of data while controlling the probability of making at least one Type I error. The complete procedure is illustrated on several model selection tasks, including the determination of the number of hidden units for feed-forward neural networks and the number of kernels for RBF networks. c 2002 Elsevier Science B.V. All rights reserved.

In this paper, stress fields at the surface of the capping layer of self-assembled InAsP quantum wires grown on an InP (001) substrate have been determined from atomistic models using molecular dynamics and Stillinger-Weber potentials. To carry out these calculations, the quantum wire compositional distribution was extracted from previous works, where the As and P distributions were determined by electron energy loss spectroscopy and high-resolution aberration-corrected Z-contrast imaging. Preferential sites for the nucleation of wires on the surface of the capping layer were studied and compared with (i) previous simulations using finite element analysis to solve anisotropic elastic theory equations and (ii) experimentally measured locations of stacked wires. Preferential nucleation sites of stacked wires were determined by the maximum stress location at the MD model surface in good agreement with experimental results and those derived from finite element analysis. This indicates that MD simulations based on empirical potentials provide a suitable and flexible tool to study strain dependent atom processes.

12 páginas, 5 figuras, 4 tablas, The boundary between the Atlantic and Indian sectors of the Southern Ocean is a key spot of the thermohaline circulation, where the following water masses mix up: Indian Central water (ICW), South Atlantic Central Water (SACW), Antarctic Intermediate Water (AAIW), Circumpolar Deep Water (CDW), North Atlantic Deep Water (NADW), Weddell Sea Deep Water (WSDW) and Antarctic Winter Water (WW). An optimum multiparameter analysis based on the distributions of potential temperature, salinity, NO (=O2+9.3×NO3) and silicate during the GoodHope 2004 (GH04) cruise allowed us to (i) define the realms of these water masses; (ii) obtain the water mass proportion weighted-average (archetypal) apparent oxygen utilization (AOU) and dissolved organic carbon (DOC) concentrations of each water mass; and (iii) estimate the contribution of DOC to the oxygen demand of the study area. WW represented only 5.2% of the water volume sampled during GH04, followed by WSDW with 10.8%, NADW with 12.7%, SACW with 15.3%, AAIW with 23.1% and CDW with 32.8%. The distributions of DOC and AOU were mainly explained by the mixing of archetypal concentrations of these variables, 75±5% and 65±3% respectively, which retained the variability due to the basin-scale mineralization from the formation area to the barycentre of each water mass along the GH04 line. DOC accounted for 26±2% and 12±5% of the oxygen demand of the meso- and bathypelagic ocean, respectively. Conversely, local mineralization processes, retained by the residuals of the archetypal concentrations of DOC and AOU, did not contribute to improve significantly the mixing model of DOC., Financial support for this work came from the Spanish Ministry of Education and Science Grant no. CGL2005-23776-E.

In patients with end-stage renal disease, successful renal allotransplantation improves the quality of life and increases survival as compared with long-term dialysis treatment.To show our experience, effectiveness and results of renal transplantations at the University Hospital of UANL.A retrospective study of renal transplantation performed at University Hospital of UANL was done. The transplant cases from 1967 to July 2001 and January 2003 to June 2011 were included.280 kidney transplants were performed in 264 patients, 146 men and 118 women; 201 from deceased donor and 79 from living donor. The patient survival at 1, 3, and 5 years was 98.8, 85.9 and 85.9%, respectively. The graft survival at 1, 3, and 5 years, censored for death with functioning graft, was 98.8, 85.7 and 74.9%, respectively.Our results, in this population with unfavorable socioeconomic conditions, are comparable to those obtained in other institutions.

Complexity-penalization strategies are one way to decide on the most appropriate network size in order to address the trade-off between overfitted and underfitted models. In this paper we propose a new penalty term derived from the behaviour of candidate models under noisy conditions that seems to be much more robust against catastrophic overfitting errors that standard techniques. This strategy is applied to several regression problems using polynomial functions, univariate autoregressive models and RBF neural networks. The simulation study at the end of the paper will show that the proposed criterion is extremely competitive when compared to state-of-the-art criteria.

This paper compares the pozzolanic activity of metakaolin (MK) obtained by thermal treatment at 700°C for 1. h and amorphous kaolin obtained by mechanochemical treatment in a Herzog oscillating mill for 15-120. min. The starting materials used included two raw kaolins and an industrial (washed) kaolin. The production of the amorphous materials was followed by their thermal analysis (DTA, TGA), X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR), particle size distribution (PSD) and transmission electron microscopy (TEM). The pozzolanic activity of the amorphous kaolins was assessed in accordance with ASTM C 311. Based on the results, both types of treatment allow reactive pozzolans to be obtained from kaolinite clays. The pozzolan obtained by mechanochemical treatment of raw kaolin with high quartz content was found to perform especially well. In sample KV2, with a minor amount of kaolinite, it was possible to obtain an active pozzolan by mechanical treatment but not by thermal treatment. The pozzolanic index and the mechanical resistances obtained by grinding were similar to the thermal treatment. The outcome of the mechanochemical process depends on the type of kaolin used and its and mineralogical composition, and also on its grinding time., The authors wish to thank the University of Valle (Colombia), the “Francisco José de Caldas” Colombian Institute for the Development of Science and Technology (COLCIENCIAS), Spain's Center of Environmental Sciences (CCMA-CSIC), and the Colombian Excellence Center for Novel Materials (CENM) for their support in the conduct of this study.

The combination of strain measurements1 and the analysis of High Angle Annular Dark Field (HAADF) Scanning Transmission Electron Microscopy (STEM) images constitutes a powerful approach to investigate strained heterostructures on the nanometer scale and has proved to be extremely powerful for characterizing nanomaterials2,3.

In this work, we analyze the influence of atomic displacements due to elastic strain in HAADF-STEM simulated images. This methodology is demonstrated on an InP/InAsxP(1−x) nanowire heterostructure theoretical model under strained/unstrained conditions. Since the HRTEM image simulation requires an enormous amount of computing power, all simulations have been obtained using a parallel version of HAADFSTEM simulation software[1] running in the University of Cadiz supercomputer (3.8 Tflops). This program is able to simulate HAADF-STEM images from nanostructures containing more than one million of atoms in a few days.

In this paper we describe a pattern recognition system implemented to determine thickness and defocus from HRTEM simulated images. A specific task has been designed to quantify the influence of certain operation parameters of a transmission electron microscope in the global recognition error rate. This influence allows us to estimate human recognition confidence when applying pattern matching to the determination of thickness and defocus from HRTEM maps. The images considered in this task correspond to InP with the sphalerite crystalline structure and were simulated using the EMS computer software package.

The goal of combining the outputs of multiple models is to form an improved meta-model with higher generalization capability than the best single model used in isolation. Most popular ensemble methods do specify neither the number of component models nor their complexity. However, these parameters strongly influence the generalization capability of the meta-model. In this paper we propose an ensemble method which generates a meta-model with optimal values for these parameters. The proposed method suggests using resampling techniques to generate multiple estimations of the generalization error and multiple comparison procedures to select the models that will be combined to form the meta-model. Experimental results show the performance of the model on regression and classification tasks using artificial and real databases.

Many natural complex systems show peculiar behaviors that are reproduced by computational systems with simple microscopic evolution rules. Here a model that was firstly intruduced for the simulation of submicronic particle deposition and deposit growth is adapted as a model for the pulmonary damage caused precisely by such particles. The model allows to specify the structure of the "pulmonary tree" by means of a dimensionless parameter and also the flow pattern of the inhaled particles (due to air drag and diffusion). The model may qualitatively reproduces particle inhalation profiles obtained through detailed simulations. A continuous decrease of pulmonary volume and oxigenation surface is found, presenting "crises" in both magnitudes.

Estimating Prediction Risk is important for providing a way of computing the expected error for predictions made by a model, but it is also an important tool for model selection. This paper addresses an empirical comparison of model selection techniques based on the Prediction Risk estimation, with particular reference to the structure of nonlinear regularized neural networks. To measure the performance of the different model selection criteria a large-scale small-samples simulation is conducted for feedforward neural networks.

In this paper we describe a methodology developed at the University of Cadiz (Spain) in the past few years for the extraction of quantitative information from electron microscopy images at the atomic level. This work is based on a coordinated and synergic activity of several research groups that have been working together over the last decade in two different and complementary fields: Materials Science and Computer Science. The aim of our joint research has been to develop innovative high-performance computing techniques and simulation methods in order to address computationally challenging problems in the analysis, modelling and simulation of materials at the atomic scale, providing significant advances with respect to existing techniques. The methodology involves several fundamental areas of research including the analysis of high resolution electron microscopy images, materials modelling, image simulation and 3D reconstruction using quantitative information from experimental images. These techniques for the analysis, modelling and simulation allow optimizing the control and functionality of devices developed using materials under study, and have been tested using data obtained from experimental samples.

One of the main research concern in neural networks is to find the appropriate network size in order to minimize the trade-off between overfitting and poor approximation. In this paper the choice among different competing models that fit to the same data set is faced when statistical methods for model comparison are applied. The study has been conducted to find a range of models that can work all the same as the cost of complexity varies. If they do not, then the generalization error estimates should be about the same among the set of models. If they do, then the estimates should be different and our job would consist on analyzing pairwise differences between the least generalization error estimate and each one of the range, in order to bound the set of models which might result in an equal performance. This method is illustrated applied to polynomial regression and RBF neural networks.

We aim to determine which of a set of competing models is statistically best, that is, on average. A way to define "on average" is to consider the performance of these algorithms averaged over all the training sets that might be drawn from the underlying distribution. When comparing more than two means, an ANOVA F-test tells you whether the means are significantly different, but it does not tell you which means differ from each other. A simple approach is to test each possible difference by a paired t-test. However, the probability of making at least one type I error increases with the number of tests made. Multiple comparison procedures provide different solutions. We discuss these techniques and apply the well known Bonferroni method in order to determine the optimal degree in polynomial fitting and the optimal number of hidden neurons in feedforward neural networks.

The distribution of bismuth in InAs1-xBix/GaAs quantum dots is analyzed by atomic-column resolution electron microscopy and imaging simulation techniques. A random Bi distribution is measured in the case of

The distribution of Bi atoms in epitaxial GaAs(1−x)Bix is analyzed through aberration-corrected Z-contrast images. The relation between the atomic number and the intensity of the images allows quantifying the distribution of Bi atoms in this material. A bidimensional map of Bi atoms is extracted showing areas where nanoclustering is possible and evidencing the location of Bi at As-substitutional positions in the lattice. The distribution of Bi atoms differs from a random spatial pattern of Bi atoms in the material.

High-Angle Annular Dark-Field Scanning Transmission Electron Microscopy (HAADF-STEM) in combination with strain mapping techniques provides a powerful tool for quantitative analysis of crystalline semiconductor materials. Due to the complex interaction of a focused probe and a sample in HAADF, the calculation of each pixel in a simulation process requires a complete multislice iteration, making the overall computing process a rather demanding task in time and memory. SICSTEM is a parallel software code recently developed for running on the University of Cadiz Supercomputer (3.75 Tflops) that allows the simulation of images from large nanostructures containing more than one million atoms. The software has been designed to be able to generate not only one dimensional line scans or two dimensional images, but also to perform optical sectioning in the STEM simulation process, providing an easy way to simulate 3D HAADF-STEM images. In this work we consider GaAs capped GaSb nanostructures epitaxially oriented on a GaAs substrate. A methodology has been developed by combining the through-focal series STEM imaging and image analysis to estimate shape and position of buried GaSb nanostructures.

Geometric phase and peak pairs strain mapping techniques have been applied to high angular annular dark field scanning transmission electron microscopy (HAADF-STEM) simulated images of an InAs/InP strained nanowire at different sample thicknesses. Strain values determined from HAADF-STEM images have been compared to theoretical values obtained by solving the elastic theory equation by finite element analysis, in order to analyze and assess both techniques in terms of accuracy of the predictions.

We show in this work that GaAs capping of 2 ML of GaSb grown by molecular beam epitaxy results in the formation of very small (with heights of about 1 nm) GaAsxSb1−x nanostructures surrounded by a GaAs rich layer. This conclusion is obtained by analyzing the morphology of the GaAsxSb1−x nanostructures by high resolution scanning transmission electron microscopy in Z-contrast mode. This result shows that a significant fraction of the Sb atoms must segregate along the growth direction during the GaAs capping process., This work was supported by the Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, U.S. DOE MFC, the SANDiE European Network of Excellence Contract No. NMP4-CT-2004-500101, the Spanish MEC Grant No. TEC2005-05781-C03-01 y 02, TEC2008-06756-C03-02/TEC, NAN2004-09109-C04-01, Consolider-Ingenio 2010 CSD2006-00019, the CAM Grant No. S 0505ESP 0200, and the Junta de Andalucía PAI research groups TEP-120 and TIC-145; projects PAI05-TEP-00383 and TEP-03516.

High angle annular dark field scanning transmission electron microscopy (HAADF-STEM) is a powerful tool to quantify size, shape, position, and composition of nano-objects with the assessment of image simulation. Due to the high computational requirements needed, nowadays it can only be applied to a few unit cells in standard computers. To overpass this limitation, a parallel software (SICSTEM) has been developed. This software can afford HAADF-STEM image simulations of nanostructures composed of several hundred thousand atoms in manageable time. The usefulness of this tool is exemplified by simulating a HAADF-STEM image of an InAs nanowire.

Strain mapping is defined as a numerical image processing technique that measures the local shifts of image details around a crystal defect with respect to the ideal, defect-free, positions in the bulk. The most common algorithms for strain mapping are based on peak finding (real space) and geometric phase (Fourier space) methods. In this paper, we discuss both algorithms and propose an alternative algorithm (Peak Pairs) based on the detection of pairs of intensity maxima in the affine transformed space which exhibits good behavior at dislocations. Quantitative results are reported from experiments to determine local stresses in different types of quantum heterostructures.