Ultimate capacity of rectangular concrete-filled steel tubular columns under unequal load eccentricities

The paper describes 36 experimental tests conducted on rectangular and square tubular columns filled with normal and high strength concrete and subjected to a non-constant bending moment distribution with respect to the weak axis. The test parameters were the nominal strength of concrete (30 and 90 MPa), the cross-section aspect ratio (square or rectangular), the thickness (4 or 5 mm) and the ratio of the top and bottom first order eccentricities e top/e bottom (1, 0.5, 0 and - 0.5). The ultimate load of each test was compared with the design loads from Eurocode 4, presenting unsafe results inside a 10% safety margin. The tests show that the use of high strength concrete is more useful for the cases of non-constant bending moment, whereas if the aim is to obtain a more ductile behavior the use of concrete-filled columns is more appealing in the cases of normal strength concrete with non-constant bending moments because, although they resist less axial force than the members with HSC, they obtain a softened post-peak behavior. © 2011 Elsevier Ltd.The authors wish to express their sincere gratitude to the Spanish Ministry of Education for the help provided through projects BIA2005_255 and BIA2009_9411, and to the European Community for FEDER funds.Hernández Figueirido, D.; Romero, ML.; Bonet Senach, JL.; Montalva Subirats, JM. (2012). Ultimate capacity of rectangular concrete-filled steel tubular columns under unequal load eccentricities. Journal of Constructional Steel Research. 68(1):107-117. https://doi.org/10.1016/j.jcsr.2011.07.014S10711768

Optimal design of prestressed concrete hollow core slabs taking into account its fire resistance

[EN] Prestressed hollow core slabs are a concrete element widely used as construction floor product, which manufacturing process has greatly been improved in recent years. Several research studies focused on hollow core slab performance, mainly related to its fire behavior, have provided new limit states to be assessed throughout its life cycle. Therefore, the hollow core slab design needs to be reviewed to allow for these improvements, a process which may involve changes to its geometry. In order to deal with this review, modern computational optimization techniques offer an alternative approach to traditional structural product design procedure, mainly based on the engineer's prior experience. This paper proposes a hollow core slab model (including variables and constraints) to develop heuristic search algorithms, such as simulated annealing, in order to find the most economical slab design including the fire resistant constraint and taking into account all available manufacturing technologies. The optimal designs obtained by this process save up to 20% in cross-section area compared with common circular void designs from market, which is taken as a comparison pattern. The results show that traditional designs are deficient when the fire resistant constraint is considered, so that precast manufacturers and machinery designers should use optimization techniques to modify their hollow core slab geometry.Albero Gabarda, V.; Saura Arnau, H.; Hospitaler Pérez, A.; Montalva Subirats, JM.; Romero, ML. (2018). Optimal design of prestressed concrete hollow core slabs taking into account its fire resistance. Advances in Engineering Software. 122:81-92. doi:10.1016/j.advengsoft.2018.05.001S819212

Influence of COVID-19 confinement in students’ performance in higher education

Documento procedente de EdArXiv Preprints , se deposita en Biblos-e Archivo versión 2 de 7 Mayo de 2020This study explores the effects of COVID-19 confinement in the students’ performance in higher education. Using a field experiment of 458 students from three different subjects in Universidad Autónoma de Madrid (Spain), we study the differences in assessments by dividing students into two groups. The first group (control) corresponds to academic years 2017/2018 and 2018/2019. The second group (experimental) corresponds to students from 2019/2020, which is the group of students that interrupted their face-to-face activities because of the confinement. The results show that there is a significant positive effect of the COVID-19 confinement on students’ performance. This effect is also significative in activities that did not change their format when performed after the confinement. We find that this effect is significative both in subjects that increased the number of assessment activities and subjects that did not change the workload of students. Additionally, an analysis of students’ learning strategies before confinement shows that students did not study on a continuous basis. Based on these results, we conclude that COVID-19 confinement changed students’ learning strategies to a more continuous habit, improving their efficiency. For these reasons, better scores in students’ assessment are expected due to COVID-19 confinement that can be explained by an improvement in their learning performanceThis work has been financed by the project Erasmus+ 2017-1-ES01-KA203-038266 Project of the European Union: “Advanced Design of e-Learning Applications Personalizing Teaching to Improve Virtual Education

Surveillance of imported malaria in Spain: The useful tool of the Semi-Nested Multiplex PCR

The use of a new PCR-based method for the diagnosis of malaria in the Spanish Malaria Reference Laboratory has promoted an increase in confirmed cases of malaria. From August 1997 to July 1998, a total of 192 whole-blood samples and 71 serum samples from 168 patients were received from the hospitals of the Spanish National Health System. Most of the patients came from west-central African countries (85%). This molecular method showed more sensitivity and specificity than microscopy, detecting 12.4% more positive samples than microscopy and 13% of mixed infections undetectable by Giemsa stain. Plasmodium falciparum was the main species detected, with 68% of the total positive malaria cases, followed by Plasmodium malariae (29%), Plasmodium vivax (14%), and Plasmodium ovale (7%), including mixed infections in all cases. This report consists of the first wide, centralized survey of malaria surveillance in Spain. The reference laboratory conducted the analysis of all imported cases in order to detect trends in acquisition. The use of a seminested multiplex PCR permitted confirmation of the origins of the infections and the Plasmodium species involved and confirmation of the effectiveness of drug treatments. This PCR also allowed the detection of the presence in Spain of primaquine-tolerant P. vivax strains from west-central Africa, as well as the detection of a P. falciparum infection induced by transfusion.This work was supported by the Fondo de Investigaciones Sanitarias (FIS) (contract number 96/0216) and the Spanish Agency of International Cooperation (AECI). J. M. Rubio was granted a postdoctoral fellowship from the Comunidad Autónoma de Madrid, Madrid, Spain. J. Alvar was supported by a B.A.E. from the FIS (contract number 99/5038) and by the Christ’s College, University of Cambridge, Cambridge, United Kingdo

Una propuesta de consenso sobre el concepto de exclusión: implicaciones metodológicas

En este texto se analiza la exclusión social desde los niveles institucional y político e individual-grupal y se profundiza en su origen estructural, su carácter multidimensional y su naturaleza procesual. En particular, se analiza la exclusión como fenómeno estructural en lo relativo a las transformaciones ocurridas en los últimos años en estructuras de integración social como el empleo, el Estado de Bienestar y las redes sociales, comunitarias y de parentesco. También se analizan diversas investigaciones nacionales e internacionales sobre la exclusión social que destacan por sus aportaciones metodológicas y se reflexiona en torno a las metodologías de análisis de la exclusión social. A este respecto, se plantean diversas sugerencias sobre los sistemas de información de los dispositivos de atención a población excluida, tanto públicos como de iniciativa social y se realiza una propuesta de indicadores multidimensional que abarca aspectos económicos, políticos y sociales

Mortality and Cardiovascular Complications in Older Complex Chronic Patients with Type 2 Diabetes

Aims/Introduction. Determining the prevalence of diabetes and its cardiovascular complications and all-cause mortality in older chronic complex patients. Materials and Methods. We carried out a multicenter retrospective study and included a randomized sample of 932 CCP people. We assessed the prevalence of diabetes according to World Health Organization criteria. Data included demographics and functional, comorbidity, cognitive, and social assessment. Results. The prevalence of diabetes was 53% and average age 81.16±8.93 years. There were no significant differences in the survival of CCP patients with or without DM, with or without ischaemic cardiopathy, and with or without peripheral vascular disease. The prognostic factors of all-cause mortality in patients with DM were age ≥ 80 years [HR 1.47, 95% CI 1.02–2.13, p  0.038], presence of heart failure [HR 1.73, 95% CI 1.25–2.38, p  0.001], Charlson score [HR 1.20, 95% CI 1.06–1.36, p  0.003], presence of cognitive impairment [HR 1.73, 95% CI 1.24–2.40, p  0.001], and no treatment with statins [HR 1.49, 95% CI 1.08–2.04, p  0.038]. Conclusions. We found high prevalence of DM among CCP patients and the relative importance of traditional risk factors seemed to wane with advancing age. Recommendations may include relaxing treatment goals, providing family/patient education, and enhanced communication strategies

Mortality and Cardiovascular Complications in Older Complex Chronic Patients with Type 2 Diabetes

Mortality; Cardiovascular diseases;Type 2 DiabetesMortalitat; Malalties cardiovasculars; Diabetis tipus 2Mortalidad; Enfermedades cardiovasculares; Diabetes tipo 2AIMS/INTRODUCTION: Determining the prevalence of diabetes and its cardiovascular complications and all-cause mortality in older chronic complex patients. MATERIALS AND METHODS: We carried out a multicenter retrospective study and included a randomized sample of 932 CCP people. We assessed the prevalence of diabetes according to World Health Organization criteria. Data included demographics and functional, comorbidity, cognitive, and social assessment. RESULTS: The prevalence of diabetes was 53% and average age 81.16 ± 8.93 years. There were no significant differences in the survival of CCP patients with or without DM, with or without ischaemic cardiopathy, and with or without peripheral vascular disease. The prognostic factors of all-cause mortality in patients with DM were age ≥ 80 years [HR 1.47, 95% CI 1.02-2.13, p  0.038], presence of heart failure [HR 1.73, 95% CI 1.25-2.38, p  0.001], Charlson score [HR 1.20, 95% CI 1.06-1.36, p  0.003], presence of cognitive impairment [HR 1.73, 95% CI 1.24-2.40, p  0.001], and no treatment with statins [HR 1.49, 95% CI 1.08-2.04, p  0.038]. CONCLUSIONS: We found high prevalence of DM among CCP patients and the relative importance of traditional risk factors seemed to wane with advancing age. Recommendations may include relaxing treatment goals, providing family/patient education, and enhanced communication strategies

Sex and gender differences in acute stroke care: metrics, access to treatment and outcome. A territorial analysis of the Stroke Code System of Catalonia

Introduction: Previous studies have reported differences in the management and outcome of women stroke patients in comparison with men. We aim to analyze sex and gender differences in the medical assistance, access to treatment and outcome of acute stroke patients in Catalonia. Patients and methods: Data were obtained from a prospective population-based registry of stroke code activations in Catalonia (CICAT) from January/2016 to December/2019. The registry includes demographic data, stroke severity, stroke subtype, reperfusion therapy, and time workflow. Centralized clinical outcome at 90 days was assessed in patients receiving reperfusion therapy. Results: A total of 23,371 stroke code activations were registered (54% men, 46% women). No differences in prehospital time metrics were observed. Women more frequently had a final diagnosis of stroke mimic, were older and had a previous worse functional situation. Among ischemic stroke patients, women had higher stroke severity and more frequently presented proximal large vessel occlusion. Women received more frequently reperfusion therapy (48.2% vs 43.1%, p < 0.001). Women tended to present a worse outcome at 90 days, especially for the group receiving only IVT (good outcome 56.7% vs 63.8%; p < 0.001), but not for the group of patients treated with IVT + MT or MT alone, although sex was not independently associated with clinical outcome in logistic regression analysis (OR 1.07; 95% CI, 0.94–1.23; p = 0.27) nor in the analysis after matching using the propensity score (OR 1.09; 95% CI, 0.97–1.22). Discussion and conclusion: We found some differences by sex in that acute stroke was more frequent in older women and the stroke severity was higher. We found no differences in medical assistance times, access to reperfusion treatment and early complications. Worse clinical outcome at 90 days in women was conditioned by stroke severity and older age, but not by sex itself