152 research outputs found

    Attenuation and diffusion produced by small-radius curvatures in POFs

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    Our aim is to characterize curvatures using a methodology previously applied to other localized disturbances in plastic optical fibers (POFs). The effects of several curvature radii and turn angles have been analyzed, so that for each condition, angular dependent attenuation and diffusion are obtained from experimental measurements to construct a matrix that accounts for the global effects of power loss and mode mixing introduced by the curvature over the angular power distribution. Power loss as a function of bend radius was calculated using the characteristic matrices and compared to experimental results to validate the model. This curvature model can be a useful tool to predict the impact of bends on transmission properties as is demonstrated in the example of a small network in a domestic environment

    Risk factors for major adverse cardiovascular events after osteoporotic hip fracture repair surgery

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    Osteoporotic hip fracture (OHF) is an increasingly frequent age-related pathology, which results in high rates of functional loss and mortality within the first year after surgery. This study assessed whether preoperative levels of brain natriuretic peptide (NT-proBNP) and troponin I were related to early occurrence (30d) of major adverse cardio-vascular events (MACE) after OHF repair surgery. During a 6-month period, perioperative clinical and analytical data from consecutive patients, without known history of cardiovascular disease and undergoing surgery for OHF repair at a single centre, were prospectively collected. MACE was defined as acute myocardial ischaemia or infarction, acute heart failure or cardiovascular death. amongst the 140 patients included, 23 (16.4%) developed postoperative MACE (MACE group) and 117 did not (Control group). Compared to those from control group, patients from MACE group were older, had poorer physical status (ASA III–IV), received preoperative red blood cell transfusion (RBCT) more frequently, presented with lower haemoglobin concentrations and higher NT-proBNP, creatinine and troponin I concentrations. Overall, RBCT requirements and 30d mortality rate were also higher in MACE group. However, in multivariate analysis, only preoperative RBCT, creatinine >1 mg/dL and NT-proBNP >450 pg/mL remained as independent preoperative risks factors for postoperative MACE, while 95% confidence intervals of odds ratios were wide. Though our findings require confirmation in a larger multicentre cohort, identifying risk factors for early postoperative MACE after OHF repair surgery, might facilitate assessing patients’ risk prior to and following surgery, and targeting them the appropriate preventive and/or therapeutic interventions

    Potencial paleoecológico de los depósitos orgánicos marinos de Posidonia oceanica

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    XV lnternational A.P.L.E. Symposium of Palynolog

    Orographic Effects on Berry Morphology and Chemical Composition of Carignan and Grenache Noir Grapes

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    A variation in the climatic parameters of an orographic vineyard influences the growth and developmentof vines and grapes. Understanding the effects of this is highly beneficial in determining how viticulturepractices can be modified to enhance grape quality. The aim of this study was to assess the effects of in-rowgrape position, altitude and vigour on berry morphology and grape maturity. The effects of vigour, altitudeand in-row grape position on berry weight and diameter, titratable acidity, pH and sugar concentrationof Carignan and Grenache noir grapes grown in a vineyard located in Priorat were investigated in the2021 vintage. The results show that Carignan grapes with a lower vigour demonstrated a higher sugarconcentration, berry weight and diameter, as well as lower titratable acidity, while the Grenache noirgrapes with a lower vigour achieved only a higher sugar concentration. The grapes at high altitude had ahigher sugar concentration in Carignan and higher titratable acidity in Grenache noir. Outer-row grapesof Carignan were characterised by lower titratable acidity and a higher sugar concentration, berry weightand diameter, while the outer-row grapes of Grenache noir displayed lower berry diameter, and a higherpH and sugar concentration. Vigour and in-row grape position have stronger effects on berry morphologyand chemical composition than altitude. Sugar concentration is more susceptible than other parameters tobe influenced by variability in the vineyard conditions

    Effects of 3% trehalose as an adjuvant treatment after lasik

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    Purpose: To evaluate the effect of 3% trehalose as an adjuvant in the standard treatment after laser-assisted in situ keratomileusis. Design: Interventional prospective comparative single-blind study. Setting: Department of Ophthalmology, Hospital Quirón Zaragoza, Spain. Methods: A total of 26 eyes (13 patients) were included, of which 12 eyes (group 1) received conventional treatment with lubricant drops of hyaluronic acid (0.15%) and 14 eyes (group 2) received, additionally, an ophthalmic solution of 3% trehalose. Pre- and postoperative quality-of-life tests and vital stains, tear breakup time, and osmolarity measurements were made. Results: We obtained statistically significant differences between the groups in the Symptom Assessment in Dry Eye test in all visits with respect to severity, and in the postoperative day 1 visit with respect to frequency, in all cases favoring the trehalose treatment. The values of osmolarity were not significantly different between groups. However, we did find significant differences in the Oxford scale in day 90 for the trehalose treatment (P<0.001), and in the National Eye Institute scale in day 30 (P=0.02). Conclusion: The results of this exploratory study indicate that the adjuvant treatment with 3% trehalose could be superior with respect to the standard treatment, with improvements in the objective and subjective parameters of tear quality

    Legume Diversity Patterns in West Central Africa

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    Objectives - Species Distribution Models (SDMs) are used to produce predictions of potential Leguminosae diversity in West Central Africa. Those predictions are evaluated subsequently using expert opinion. The established methodology of combining all SDMs is refined to assess species diversity within five defined vegetation types. Potential species diversity is thus predicted for each vegetation type respectively. The primary aim of the new methodology is to define, in more detail, areas of species richness for conservation planning. Methodology - Using Maxent, SDMs based on a suite of 14 environmental predictors were generated for 185 West Central African Leguminosae species, each categorised according to one of five vegetation types: Afromontane, coastal, non-flooded forest, open formations, or riverine forest. The relative contribution of each environmental variable was compared between different vegetation types using a nonparametric Kruskal-Wallis analysis followed by a post-hoc Kruskal-Wallis Paired Comparison contrast. Legume species diversity patterns were explored initially using the typical method of stacking all SDMs. Subsequently, five different ensemble models were generated by partitioning SDMs according to vegetation category. Ecological modelers worked with legume specialists to improve data integrity and integrate expert opinion in the interpretation of individual species models and potential species richness predictions for different vegetation types. Results/Conclusions - Of the 14 environmental predictors used, five showed no difference in their relative contribution to the different vegetation models. Of the nine discriminating variables, the majority were related to temperature variation. The set of variables that played a major role in the Afromontane species diversity model differed significantly from the sets of variables of greatest relative important in other vegetation categories. The traditional approach of stacking all SDMs indicated overall centers of diversity in the region but the maps indicating potential species richness by vegetation type offered more detailed information on which conservation efforts can be focused

    Evaluation of dimensionality reduction methods applied to numerical weather models for solar radiation forecasting

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    The interest in solar radiation prediction has increased greatly in recent times among the scientific community. In this context, Machine Learning techniques have shown their ability to learn accurate prediction models. The aim of this paper is to go one step further and automatically achieve interpretability during the learning process by performing dimensionality reduction on the input variables. To this end, three non standard multivariate feature selection approaches are applied, based on the adaptation of strong learning algorithms to the feature selection task, as well as a battery of classic dimensionality reduction models. The goal is to obtain robust sets of features that not only improve prediction accuracy but also provide more interpretable and consistent results. Real data from the Weather Research and Forecasting model, which produces a very large number of variables, is used as the input. As is to be expected, the results prove that dimensionality reduction in general is a useful tool for improving performance, as well as easing the interpretability of the results. In fact, the proposed non standard methods offer important accuracy improvements and one of them provides with an intuitive and reduced selection of features and mesoscale nodes (around 10% of the initial variables centered on three specific nodes).This work has been partially supported by the projects TIN2014-54583-C2-2-R, TEC2014-52289-R and TEC2016-81900-REDT of the Spanish Interministerial Commission of Science and Technology (MICYT), and by Comunidad Autónoma de Madrid, under project PRICAM P2013ICE-2933

    ARE WE READY FOR A CHRONIC CRISIS? REFLECTIONS ON THE EXPERIENCE OF TEACHING DURING CONFINEMENT

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    [EN] The lockdown period that started on March 2020 due to the COVID-19 pandemic was a big challenge for students and teachers. Technology made the continuation of the teaching easier, and it also allowed teachers to keep the contact both with colleagues and with students. New teaching and evaluation methodologies and new coordination and cooperation systems had to be quickly implemented. Our previous experience in flipped teaching, active methodologies and validation of online exams, helped us to tackle the transition from face-to-face to fully online teaching. The experience was satisfactory for the theory classes, but some problems in the laboratory classes have emerged. After that, right now, some extra work is needed to overcome these difficulties considering that maybe the situation would become chronic. Once that we got over the shock of the first moment, the question is whether the resilience mechanisms will remain, and if the hybrid teaching (face-to-face & online) can replace effectively face-to-face teaching for a long time. In this work we present the students¿ opinion on this question. The analysis has been performed at the School of Design Engineering of the Universitat Politècnica de València, in different courses of physics of several engineering degrees (all of them, first academic year courses). One example of good practice during confinement was the weekly coordination meetings between teachers of the same course and between teachers of physics courses in different degrees. Another one was the online exams, taking advantage of the automatic correction tests, and including images of the documents written by the students for later review. The academic results were comparable to those of a normal course and student and teachers' surveys were conducted to know their opinion. The good performance during this new situation was due to the collaboration, patience, understanding and trust of the students and teachers that was created in those moments of crisis. Students' opinion on the online teaching during their lockdown was positive. This work shows this students' opinion on the methodology used during the lockdown, and the process from previous flipped teaching methodologies experiences to a completely online teaching. At the same time, the students' opinion on the laboratory practices was also analysed. Finally, this work also shows the reflection of the involved teachers on the additional workload and on the capacity for cooperation and communication between them, during the lockdown period and the subsequent year. After gathering the opinion of teachers and students, we can conclude that the situation of the pandemic has been addressed with reasonable success. Performance of students is not affected, the theoretical classes have been developed normally, while the practical classes seem to need some changes to be adapted to the new situation as far as possible. Given that this situation persists, it is useful to carry out this type of study to be able to adapt teaching to future circumstances.Authors would like to thank the Institute of Education Sciences of the Universitat Politècnica de València (Spain) for supporting the Teaching Innovation Group e-MACAFI and for the financial support through PIME Project PIME/2018/B25 and PIME Project PIME/2018/B26Tort-Ausina, I.; Vidaurre, A.; Riera Guasp, J.; Gamiz-Gonzalez, M.; Meseguer Dueñas, JM.; Gómez-Tejedor, J.; Quiles Casado, SDLS.... (2021). ARE WE READY FOR A CHRONIC CRISIS? REFLECTIONS ON THE EXPERIENCE OF TEACHING DURING CONFINEMENT. IATED Academy. 359-367. https://doi.org/10.21125/edulearn.2021.0117S35936

    Role of carbonate burial in Blue Carbon budgets

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    Calcium carbonates (CaCO 3 ) often accumulate in mangrove and seagrass sediments. As CaCO 3 production emits CO 2 , there is concern that this may partially offset the role of Blue Carbon ecosystems as CO 2 sinks through the burial of organic carbon (C org ). A global collection of data on inorganic carbon burial rates (C inorg , 12% of CaCO 3 mass) revealed global rates of 0.8 TgC inorg yr −1 and 15–62 TgC inorg yr −1 in mangrove and seagrass ecosystems, respectively. In seagrass, CaCO 3 burial may correspond to an offset of 30% of the net CO 2 sequestration. However, a mass balance assessment highlights that the C inorg burial is mainly supported by inputs from adjacent ecosystems rather than by local calcification, and that Blue Carbon ecosystems are sites of net CaCO 3 dissolution. Hence, CaCO 3 burial in Blue Carbon ecosystems contribute to seabed elevation and therefore buffers sea-level rise, without undermining their role as CO 2 sinks. © 2019, The Author(s)
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