Colour Constancy: Biologically-inspired Contrast Variant Pooling Mechanism

Pooling is a ubiquitous operation in image processing algorithms that allows for higher-level processes to collect relevant low-level features from a region of interest. Currently, max-pooling is one of the most commonly used operators in the computational literature. However, it can lack robustness to outliers due to the fact that it relies merely on the peak of a function. Pooling mechanisms are also present in the primate visual cortex where neurons of higher cortical areas pool signals from lower ones. The receptive fields of these neurons have been shown to vary according to the contrast by aggregating signals over a larger region in the presence of low contrast stimuli. We hypothesise that this contrast-variant-pooling mechanism can address some of the shortcomings of max-pooling. We modelled this contrast variation through a histogram clipping in which the percentage of pooled signal is inversely proportional to the local contrast of an image. We tested our hypothesis by applying it to the phenomenon of colour constancy where a number of popular algorithms utilise a max-pooling step (e.g. White-Patch, Grey-Edge and Double-Opponency). For each of these methods, we investigated the consequences of replacing their original max-pooling by the proposed contrast-variant-pooling. Our experiments on three colour constancy benchmark datasets suggest that previous results can significantly improve by adopting a contrast-variant-pooling mechanism

El legado del Aljarafe: una ruta por las haciendas de olivar

En el presente trabajo se da a conocer el patrimonio existente en la comarca del Aljarafe, provincia de Sevilla. Este patrimonio refleja el paso de diferentes corrientes artísticas, por lo que merece ser visitado. Además, el propósito principal de este trabajo es fomentar el turismo en el Aljarafe a través de la creación de una ruta por las haciendas de olivar construidas entre los siglos XVI y XVIII. Esta ruta muestra la importancia que tuvieron las haciendas en su época de esplendor y la relevancia de la actividad agrícola para esta comarca. Gracias a las buenas condiciones de sus tierras, el Aljarafe siempre se ha caracterizado por sus cultivos de olivo y vid, un legado que aún está presente en las generaciones actuales.Universidad de Sevilla. Grado en Turism

A review on characterization of pillared clays by specific techniques

[EN]The use of specific characterization techniques, namely Thermal Analysis, Near Infrared Spectroscopy, Ultraviolet–Visible Spectroscopy, Electron Paramagnetic Resonance, Mössbauer Spectroscopy and Neutron Scattering, in the characterization of pillared clays is reviewed. Special emphasis is placed in the information provided by each of these techniques in the characterization of pillared clays

Microwave-Assisted Pillaring of a Montmorillonite with Al-Polycations in Concentrated Media

[EN]A montmorillonite has been intercalated with Al3+ polycations, using concentrated solutions and clay mineral dispersions. The reaction has been assisted by microwave radiation, yielding new intercalated solids and leading to Al-pillared solids after their calcination at 500 C. The solids were characterized by elemental chemical analysis, X-ray diffraction, FTIR spectroscopy, thermal analyses, and nitrogen adsorption. The evolution of the properties of the materials was discussed as a function of the preparation conditions. Microwave treatment for 2.5 min provided correctly pillared solids

Synthesis and characterization of organosaponites. Thermal behavior of their poly(vinyl chloride) nanocomposites

[EN]The aim of this work was to synthesize and characterize the structural properties of the materials resulting from the combination of a synthetic saponitewith several organicmolecules, namely, Arquad 2HT-75, octadecylamine, 3-aminopropyltriethoxysilane, trimethyloctadecylammonium bromide and tetraethoxysilane, or combinations of them, and with or without the addition of HCl during synthesis. The ratios organic molecule/saponite and HCl/organic molecule were considered as synthesis variables. Structural characterization was based on X-ray diffraction (XRD), simultaneous thermogravimetric/differential thermal analysis (TG/DTA) and infrared spectroscopy (FTIR). The chemical composition of the materials was determined through X-ray fluorescence (XRF) and atomic absorption spectroscopy (AAS), and theirmorphologywas analyzed through scanning electron microscopy (SEM). The values obtained for the basal spacings were a function of the type and amount of the organic molecule. Otherwise, HCl did not significantly influence the basal spacing, but it had the capacity to significantly modify the morphology and the chemical composition of the samples. From the results found, the solids modified with tetraethoxysilane and 3-aminopropyltriethoxysilane were selected to incorporate various titaniumprecursors. These neworgano-modified saponiteswere used in the formulation of PVC nanocomposites and their thermal behavior was evaluated at two temperatures (70 and 180 °C).This work was funded by the Spanish Ministry of Science and Innovation (MICINN) and the European Regional Development Fund (FEDER)IPT-420000-2010-01

Structural, textural and acidic properties of Cu-, Fe- and Cr-doped Ti-pillared montmorillonites

Montmorillonite has been treated with Ti-based solutions, alone or doped with Cu2 +, Fe3 + or Cr3 + cations, yielding new intercalated solids, which have been calcined at various temperatures to test the stability of the so-formed pillars. The solids calcined at 500 °C were fully characterized by chemical analysis, X-ray diffraction, FT-IR spectroscopy, thermal analyses, nitrogen adsorption and acidity evaluation. The evolution of the specific surface area, porosity and acidic properties is discussed, analysing the effect of pillaring and doping procedures on these propertie

Dosimetric impact of bladder filling on organs at risk with barium contrast in the small bowel for adjuvant vaginal cuff brachytherapy

Purpose: The aim of this prospective study was to analyze dosimetric impact of modifying bladder filling on dose distribution in organs at risk (OARs) when using contrast in the small bowel of patients under adjuvant therapy with high-dose-rate vaginal cuff brachytherapy (HDR-VCB) for endometrial cancer. Material and methods: This research included 19 patients who underwent laparoscopic surgery. They were treated with HDR-VCB and 2.5-3.5 cm diameter cylinders. Two successive computerized tomography (CT) scans were performed, with empty bladder and with bladder filled with 180 cc of saline solution. Bladder, rectum, sigmoid, and small bowel were delineated as OARs. Oral barium contrast was used to clearly visualize small bowel loops. Prescription dose was 7 Gy. Dose-volume histograms were generated for each OAR, with full and empty bladder to compare doses received. Results: Bladder distension had no dosimetric impact on the bladder, rectum, or sigmoid, unlike the small bowel. With full bladder, mean minimum dose at 2 cc (D2cc) was not significantly higher for full vs. empty bladder (5.56 vs. 5.06 Gy, p = 0.07), whereas there was a significant reduction in the small bowel (1.68 vs. 2.70 Gy, p < 0.001). With full bladder, the dose increased to 50% of the volume (D50%) of the bladder (2.11 vs. 1.28 Gy, p < 0.001), and decreased in the small bowel (0.70 vs. 1.09 Gy, p < 0.001). Conclusions: The present study describes the dose received by organs at risk during HDR-VCB, making it possible to define the dose received by small bowel loops, when visualized with oral barium contrast. In patients undergoing laparoscopic surgery, a full bladder during HDR-VCB reduces the dose to the small bowel without a clinically relevant dose increase in the bladder, and no dose increase in other OARs

A Hierarchical Machine Learning Solution for the Non-Invasive Diagnostic of Autonomic Dysreflexia

More than half of patients with high spinal cord injury (SCI) suffer from episodes of autonomic dysreflexia (AD), a condition that can lead to lethal situations, such as cerebral haemorrhage, if not treated correctly. Clinicians assess AD using clinical variables obtained from the patient’s history and physiological variables obtained invasively and non-invasively. This work aims to design a machine learning-based system to assist in the initial diagnosis of AD. For this purpose, 29 patients with SCI participated in a test at Cruces University Hospital in which data were collected using both invasive and non-invasive methods. The system proposed in this article is based on a two-level hierarchical classification to diagnose AD and only uses 35 features extracted from the non-invasive stages of the experiment (clinical and physiological features). The system achieved a 93.10% accuracy with a zero false negative rate for the class of having the disease, an essential condition for treating patients according to medical criteria.This work was partially funded by the Department of Education, Universities and Research of the Basque Government (ADIAN, IT-980-16), by the Spanish Ministry of Science, Innovation and Universities-National Research Agency and the European Regional Development Fund-ERDF (PhysComp, TIN2017-85409-P), and from the State Research Agency (AEI, Spain) under grant agreement No. RED2018-102312-T (IA-Biomed)

Zoonotic pathogens in fluctuating common vole (Microtus arvalis) populations : occurrence and dynamics

Supplementary material. The supplementary material for this article can be found at https://doi.org/10.1017/S0031182018001543 Acknowledgements. We thank José Luis Guzman for helping with fieldwork and Fabio Flechoso for helping with ectoparasite counts and flea identification. Financial support. R.R.P. was supported by a Ph.D.-studentship from the University of Valladolid (co-funded by Banco Santander, RR 30/04/2014). This work was supported by ECOCYCLES (Partner 5 –EUI2008-03658), ECOVOLE (CGL2012-35348), ECOTULA (CGL2015-66962-C2-1-R) and RESERTULA (CLG2015-66962-C2-2-R) projects funded by Ministerio de Economía y Competitividad, Government of Spain.Peer reviewedPostprin