855 research outputs found

    Real-time Monocular Object SLAM

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    We present a real-time object-based SLAM system that leverages the largest object database to date. Our approach comprises two main components: 1) a monocular SLAM algorithm that exploits object rigidity constraints to improve the map and find its real scale, and 2) a novel object recognition algorithm based on bags of binary words, which provides live detections with a database of 500 3D objects. The two components work together and benefit each other: the SLAM algorithm accumulates information from the observations of the objects, anchors object features to especial map landmarks and sets constrains on the optimization. At the same time, objects partially or fully located within the map are used as a prior to guide the recognition algorithm, achieving higher recall. We evaluate our proposal on five real environments showing improvements on the accuracy of the map and efficiency with respect to other state-of-the-art techniques

    Optimal dose calibration in radiotherapy

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    In this paper, the tools provided by the theory of Optimal Experimental Design are applied to a nonlinear calibration model. This is motivated by the need of estimating radiation doses using radiochromic films for radiotherapy purposes. The calibration model is in this case nonlinear and the explanatory variable cannot be worked out explicitly from the model. In this case an experimental design has to be found on the dependent variable. For that, the inverse function theorem will be used to obtain an information matrix to be optimized. Optimal designs on the response variable are computed from two different perspectives, first for fitting the model and estimating each of the parameters and then for predicting the proper dose. While the first is a common point of view in a general context of the Optimal Experimental Design, the latter is actually the main objective of the calibration problem for the practitioners and algorithms for computing these optimal designs are also provided. The optimal designs obtained have just three different points in their support, but practitioners usually demand for more support points. Thus, a methodology for computing space-filling designs is also provided when the support points are forced to follow some mathematical rule, such as arithmetic or geometric sequences. Cross efficiencies of all these designs are computed in order to show their ability for different goals

    NTMC2T5: lipid transfer proteins at ER-chloroplast contact sites involved in plant stress.

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    Chloroplasts are the site of fatty acid synthesis in plants; however, these fatty acids are assembled into glycerolipids at the ER. Later on, some of these ER-assembled glycerolipids will be transferred back to the chloroplasts to be further modified and to form part of the chloroplastic membranes. Previous reports have shown that under some abiotic stresses, these plastid membranes suffer a large lipid remodelling and new precursors massively need to be transported from the ER to the chloroplast or vice versa. It has been suggested that the newly synthetized ER lipids are delivered to chloroplast via a non-vesicular pathway, likely through lipid transport proteins (LTP). These LTP would be localized in membrane contact sites (MCS). Some LTP at MCS contain particular domains, as the synaptotagmin-like mitochondrial lipid-binding (SMP) domain. We have studied the occurrence of SMP proteins in A. thaliana and S. lycopersicum. By using transient expression in N. benthamiana leaves and confocal microscopy, we have identified the NTMC2T5 family with two homologs in A. thaliana and only one in S. lycopersicum. They are anchored to the chloroplast outer membrane, and they interact in trans with the ER (ER-chloroplast MCS). We have observed that clustering of chloroplasts around the nucleus occurred when we overexpressed these proteins and Arabidopsis double knock-out mutant for these proteins showed less chloroplasts attached to nuclei at control conditions. And, we have investigated the NTMC2T5 protein domains involved in this clustering. Moreover, our analysis has demonstrated that Arabidopsis simple mutants show lower germination rates in media supplemented with NaCl and lower rates of expanded cotyledons in media supplemented with ABA. We have also performed biotinylation-based proximity labelling proteomics experiments in order to identify interactors of these proteins. Finally, we have performed lipidomic analysis to understand the role of these proteins.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Dissecting the role of NtrC and RpoN in the expression of assimilatory nitrate and nitrite reductases in Bradyrhizobium diazoefficiens

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    Bradyrhizobium diazoefficiens, a nitrogen- fixing endosymbiont of soybeans, is a model strain for studying rhizobial denitrification. This bacterium can also use nitrate as the sole nitrogen (N) source during aerobic growth by inducing an assimilatory nitrate reductase encoded by nasC located within the narK-bjgb-flp-nasC operon along with a nitrite reductase encoded by nirA at a different chromosomal locus. The global nitrogen two-component regulatory system NtrBC has been reported to coordinate the expression of key enzymes in nitrogen metabolism in several bacteria. In this study, we demonstrate that disruption of ntrC caused a growth defect in B. diazoefficiens cells in the presence of nitrate or nitrite as the sole N source and a decreased activity of the nitrate and nitrite reductase enzymes. Furthermore, the expression of narK-lacZor nirA-lacZ transcriptional fusions was significantly reduced in the ntrC mutant after incubation under nitrate assimilation conditions. AB. diazoefficiens rpoN 1/2 mutant, lacking both copies of the gene encoding the alternative sigma factor σ54, was also defective in aerobic growth with nitrate as the N source as well as in nitrate and nitrite reductase expression. These results demonstrate that the NtrC regulator is required for expression of the B. diazoefficiens nasC and nirA genes and that the sigma factor RpoN is also involved in this regulation.Instituto de Biotecnologia y Biologia Molecula

    Parental support for physical activity in schoolchildren and its influence on nutritional status and fitness = Apoyo parental para realizar actividad física en escolares de 6 años de edad: influencia sobre el estado nutricional y fitness

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    Introduction: Parents are key models for transmitting and teaching healthy lifestyle habits to their children. Our objective was to determine the influence of the economic and motivational support, and parental involvement in their children physical activity (PA) and its relationship with nutritio nal status and cardiorespiratory fitness. Subjects and Method: Cross-sectional study which included 70 six-year-old schoolchildren. Parents completed the “The Parental Influence on Physical Activity Scale” questionnaire. Anthropometric variables were measured according to the Chilean Ministerial Technical Standard for the supervision of children from 0 to 9 years old; PA intensity was measured with triaxial accelerometers GT3X and the VO2max estimation was performed using the Navette Course test. Results: The average body mass index was 17.9 ± 2.9 kg/m2, the obesity prevalence and VO2max were 57.1%, and 38.05 ± 16.9 ml/kg/min, respectively. Moderate PA during the physical education (PE) class was significantly higher in boys compared to girls (p < 0.006). The economic and motivational support of the parents did not significantly influence the body weight of the children, BMI, waist circumference, PA intensity, and VO2max. Children supported by their parent showed significant differences with moderate PA performed in PE compared to those who were not suppor ted by parents (p = 0.023). Conclusions: Parental support of their children in performing physical activity influences the levels of moderate PA that they do during PE classes. This type of study should be continued and the PA should be measured daily

    Psychometric properties and factor structure of the brief Wisconsin Inventory of Smoking Dependence Motives among Spanish smokers from the general population

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    Introduction: The brief version of the Wisconsin Inventory of Smoking Dependence Motives (B-WISDM) is a well-established instrument to measure the multidimensional nature of nicotine dependence. However, no previous research has assessed its psychometric properties in the Spanish context. The aim of the present study was to analyze the factor structure and measurement invariance across gender of this instrument among Spanish smokers from the general population. Methods: This cross-sectional study assessed 480 smokers through an online questionnaire including information on tobacco use and several nicotine dependence measures. Confirmatory Factor Analysis was used to assess the factorial structure of the Spanish B-WISDM, its internal consistency, measurement invariance across gender and convergent validity with the Fagerstr¨om Test for Nicotine Dependence (FTND) and the Glover-Nilsson Smoking Behavioral Questionnaire (GN-SBQ) scores. Results: Results indicate that the eleven correlated factors solution had a better fit when compared to the other tested models (two correlated factors and two second-order factors with eleven first-order correlated factors solution), remaining such structure invariant across gender. Internal consistency of the scale was high (α =0.950; dimension α values ranged between 0.657 and 0.921). Overall scores and dimensions of the scale significantly and positively correlated with other nicotine dependence measures (except for Social/Environmental Goads and FTND). Conclusions: This is the first version of the B-WISDM validated to assess nicotine dependence with a multidimensional perspective within the Spanish culture. Results show adequate psychometric properties regarding its factor structure and measurement invariance across gender, supporting its utility to evaluate the motives driving tobacco use among Spanish smokers from the general population

    Correlation between periodontal disease management and metabolic control of type 2 diabetes mellitus: a systematic literature review

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    Background: Diabetes and periodontal disease share common features in terms of inflammatory responses. Current scientific evidence suggests that treatment of periodontal disease might contribute to glycemic control. The objective of the study is a review of the last three years. Material and Methods: A literature search was performed in the MEDLINE (PubMed), Cochrane, and Scopus databases, for articles published between 01-01-2013 and 30-06-2015, applying the key terms “periodontal disease” AND “diabetes mellitus”. The review analyzed clinical trials of humans published in English and Spanish. Results: Thirteen clinical trials were reviewed, representing a total of 1,912 patients. Three of them had samples of 40 patients, representing a total of 1,804. Only one article achieved a Jadad score of five. Seven articles (998 patients, 52.3% total), presented a statistically significant decrease in HbA1c (p<0.05) as a result of periodontal treatment. In the six remaining articles (representing 914 patients, 47.8% of the total), the decrease in HbA1c was not significant. Patient follow-up varied between 3 to 12 months. In three articles, the follow-up was of 3, 4, and 9 months, in two 6 and 12 months. Conclusions: The majority of clinical trials showed that radicular curettage and smoothing, whether associated with antibiotics or not, can improve periodontal conditions in patients with diabetes mellitus. However, few studies suggest that this periodontal treatment improves metabolic control. However, there is no clear evidence of a relation between periodontal treatment and improved glycemic control in patients with type 2 diabetes mellitu

    Sphere rolling on the surface of a cone

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    We analyse the motion of a sphere that rolls without slipping on a conical surface having its axis in the direction of the constant gravitational field of the Earth. This nonholonomic system admits a solution in terms of quadratures. We exhibit that the only circular of the system orbit is stable and furthermore show that all its solutions can be found using an analogy with central force problems. We also discuss the case of motion with no gravitational field, that is, of motion on a freely falling cone.Comment: 12 pages, 2 figures, to be published in Eur J Phy

    Guadalfeo and Adra submarine deltas evolution in response to sediment supply variations

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    The Guadalfeo and the Adra submarine deltas off the northern coast of the Alboran Sea have been built up under the direct influence of short and mountainous rivers. The area is subjected to strong climatic seasonality, with sporadic winter torrential floods and high summer aridity. In addition numerous anthropogenic activities have affected these systems, mostly during the last two centuries. In order to decode the influence of climatic variability and anthropogenic impacts on sediment supplies during the recent past, five sediment cores were collected from the Guadalfeo and Adra submarine deltas. Benthic foraminiferal and sedimentological analyses, combined with radiocarbon dating, were performed. The impact of torrential floods alternating with periods of low rainfall or dry periods were recorded in the Adra and Guadalfeo prodeltas. Periods with low abundance of benthic foraminifera and high amounts of coarse-grained sediments, were interpreted as the result of enhanced sediment supply to the shelf triggered by major flood events. On the other hand, periods with high amounts of fine-grained sediments and high abundances of colonizers and opportunistic foraminiferal species indicate the establishment of new environments with distinct ecological constraints. These environments were driven by lower sediment supplies during low rainfall or dry periods. The most recent sedimentation seems to reflect the human interventions in the rivers basins, such as deviation of the main river courses and dams construction, which reduced the sediment input and promoted the deposition of shallow-water submarine deltas.info:eu-repo/semantics/publishedVersio

    Modulating between 2e<sup>-</sup> and 4e<sup>-</sup> pathway in the oxygen reduction reaction with laser-synthesized iron oxide-grafted nitrogen-doped carbon

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    In this study, we demonstrate the tuning of the oxygen reduction reaction (ORR) by iron/iron oxide nanoparticle grafted laser-patterned nitrogen-doped carbon (LP-NC) electrodes. Depending on the preparation route, i.e. addition of a molecular Fe(NO3)2 precursor before (route 1) or after pre-carbonization (route 2) of the citric acid / urea precursors, either the 4e- or the 2e- pathway in the ORR is facilitated leading to either H2O or H2O2 as a reaction product, respectively. The kinetic reaction conditions afford mixed valence metal oxide nanoparticles embedded in LP-NC in the form of either Fe2O3/Fe or Fe2O3/FeO/Fe, respectively, facilitated by an in situ carbothermal reduction during the laser-induced carbonization. In HR(S)TEM analysis we found evidence for the occurrence of Fe2O3 in the η- or α- phase, depending on the preparation route. Reciprocally, the graphitization is also affected by the preparation route leading to either homogeneous graphitization or locally a graphitized shell structures around the nanoparticles. In the 4e- mediated ORR facilitated by η-Fe2O3/Fe@LP-NC onset potentials as low as 0.70 V (vs. RHE) with a H2O2 production efficiency 4% and 10 % in alkaline and neutral electrolyte, respectively, were determined. On the other hand, α-Fe2O3/FeO/Fe@LP-NC present onset potentials for the 2e- mediated ORR is as low as 0.77 with a H2O2 production efficiency of nearly 80%
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