142 research outputs found

    Survey on Federated Learning Threats: concepts, taxonomy on attacks and defences, experimental study and challenges

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    Federated learning is a machine learning paradigm that emerges as a solution to the privacy-preservation demands in artificial intelligence. As machine learning, federated learning is threatened by adversarial attacks against the integrity of the learning model and the privacy of data via a distributed approach to tackle local and global learning. This weak point is exacerbated by the inaccessibility of data in federated learning, which makes harder the protection against adversarial attacks and evidences the need to furtherance the research on defence methods to make federated learning a real solution for safeguarding data privacy. In this paper, we present an extensive review of the threats of federated learning, as well as as their corresponding countermeasures, attacks versus defences. This survey provides a taxonomy of adversarial attacks and a taxonomy of defence methods that depict a general picture of this vulnerability of federated learning and how to overcome it. Likewise, we expound guidelines for selecting the most adequate defence method according to the category of the adversarial attack. Besides, we carry out an extensive experimental study from which we draw further conclusions about the behaviour of attacks and defences and the guidelines for selecting the most adequate defence method according to the category of the adversarial attack. This study is finished leading to meditated learned lessons and challenges

    Hybrid chitosan derivative-carbon suport for oxygen reduction reactions

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    New hybrid chitosan derivative-carbon black was prepared and used as support for Pt nanoparticles. These catalysts improved the activity toward oxygen reduction reaction (ORR), compared with those of commercial Pt/C catalyst. The biopolymer chitosan provided an efficient and sustainable surface nitrogen source associated with the superior performance of the catalysts.Peer reviewe

    Optimising an outdoor membrane photobioreactor for tertiary sewage treatment

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    The operation of an outdoor membrane photobioreactor plant which treated the effluent of an anaerobic membrane bioreactor was optimised. Biomass retention times of 4.5, 6, and 9 days were tested. At a biomass retention time of 4.5 days, maximum nitrogen recovery rate:light irradiance ratios, photosynthetic efficiencies and carbon biofixations of 51.7 ± 14.3 mg N·mol−1, 4.4 ± 1.6% and 0.50 ± 0.05 kg CO2·m3influent, respectively, were attained. Minimum membrane fouling rates were achieved when operating at the shortest biomass retention time because of the lower solid concentration and the negligible amount of cyanobacteria and protozoa. Hydraulic retention times of 3.5, 2, and 1.5 days were tested at the optimum biomass retention times of 4.5 days under non-nutrient limited conditions, showing no significant differences in the nutrient recovery rates, photosynthetic efficiencies and membrane fouling rates. However, nitrogen recovery rate:light irradiance ratios and photosynthetic efficiency significantly decreased when hydraulic retention time was further shortened to 1 day, probably due to a rise in the substrate turbidity which reduced the light availability in the culture. Optimal carbon biofixations and theoretical energy recoveries from the biomass were obtained at hydraulic retention time of 3.5 days, which accounted for 0.55 ± 0.05 kg CO2·m−3influent and 0.443 ± 0.103 kWh·m−3influent, respectively

    Selective Oxidation of Glycerol via Acceptorless Dehydrogenation Driven by Ir(I)-NHC Catalysts

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    After pandemic, healthcare workers experienced a series of emotional and psychological disturbances that could impact their mental well-being. In this study, the feasibility of morphological characteristics of photoplethysmographic (PPG) waveform to quantify stress and depression level posed by COVID-19 in first-line healthcare workers is explored. Results show that higher stress and depression level are moderately correlated with large systolic amplitude and parameters that might indicate early wave reflection. These results suggest that an arterial stiffness, quantified with PPG morphological characteristics, could provide valuable information in assessing mental healt

    Pharmacotherapy negative outcomes resulting in Primary Care Emergency visits

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    Objetivo Analizar la prevalencia de los resultados negativos asociados a la medicación (RNM) que son causa de consulta en un servicio de urgencias de atención primaria (SUAP) en un entorno rural. Determinar la evitabilidad y la gravedad de los mismos. Diseño Estudio observacional descriptivo transversal. Emplazamiento SUAP de Mula. Murcia. Participantes Un total de 330 pacientes, en un periodo de 33 semanas. Mediciones principales Número y tipo de RNM: el farmacéutico, a través de los datos obtenidos de un cuestionario validado y la historia clínica, evaluó si existía relación entre los medicamentos que toma el paciente y el motivo de acudir a urgencias. En caso de sospecha de RNM se reevaluaba con el médico y se confirmaban o no los RNM identificados. Resultados De los 330 pacientes fueron evaluables 317. La media de edad de los pacientes era de 39,63 años y el 51,42% eran mujeres. La media de medicamentos que utilizaban fue de 1,38. Se detectaron un 26,50% (IC 95% 21,94-31,62) de pacientes con RNM como causa de visita a urgencias. El 53,57% de los RNM detectados fue de la categoría de efectividad y el 40,48% de necesidad. El 77,41% (IC-95% 67,35-85,01) de las visitas causadas por RNM fueron evitables. En cuanto a la gravedad, el 92,986% de los RNM eran leves. Conclusiones Una de cada 4 visitas al SUAP de Mula está causada por un RNM y, de ellas, el 77,41% son evitables.Objective Our aim was to estimate the prevalence of Pharmacotherapy negative outcomes in Primary Care Emergency visits in a rural environment, and to determine their preventability and severity. Design Descriptive study with an analytical component. Site Primary Care Emergency Service (SUAP), Mula. Murcia. Patients The study consisted of 330 patients over a 33 week period. Method Number and type of Pharmacotherapy negative outcomes: Pharmacist through the data, a validated questionnaire and medical history, assessing whether there was a relationship between the medications and the patient, and the reason for going to the Primary Care Emergency. In case of suspicion of Pharmacotherapy negative outcomes the patient is reassessed by the doctor, and the Pharmacotherapy negative outcomes confirmed or not identified. Results Of the 330 patients, 317 were evaluable. The mean age of patients was 39.63 years and 51.42% were women. The mean number of drugs used was 1.38, and 26.50% (95% CI, 21.94% -31.62%) patients were detected with Pharmacotherapy negative outcomes as a cause of visiting the Primary Care Emergency. 53.57% of the detected Pharmacotherapy negative outcomes detected as regards efficacy was 53.75%, 40.48% as regards need. More than three-quarters (77.41%; 95% CI, 67.35% -85.01%) of emergency visits caused by Pharmacotherapy negative outcomes were avoidable. In terms of severity, 92.86% of the Pharmacotherapy negative outcomes were mild. Conclusions One in four Mula SUAP visits are due to a Pharmacotherapy negative outcomes, and 77.41% of them are preventable

    Conhecimento tradicional dos Mbyá Guaraní do Paraguai: Dioscorea spp. e Dichorisandra hexandra (Aubl.) Standl., aspectos alimentares e simbólicos.

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    O presente trabalho forma parte de um projeto denominado “As espécies de plantas silvestres comestíveis das comunidades Mbyá - Guarani da Reserva do Parque Nacional San Rafael, Itapúa, Paraguai”. O objetivo principal da pesquisa é avaliar o conhecimento sobre os usos das espécies vegetais silvestres dos Mbyá - Guaraní da Reserva do Parque San Rafael, no departamento de Itapúa, no Paraguai. Neste trabalho apresentamos as espécies silvestres registradas até o momento, cujos órgãos de reserva subterrâneos são utilizados na alimentação.CONACYT - Consejo Nacional de Ciencias y TecnologíaPROCIENCI

    Design of an innovative learning experience for the final project of the building engineering degree

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    This essay presents the bases for a new teaching methodology for the Final Project of the Degree of Building Engineering. The aim of this methodology is to approach students to advanced forms of work in architectural and engineering offices by employing Building Information Modelling (BIM) technologies. This initiative has been funded within the Call 2011 for Teaching Research Incentives ofthe I Teaching Plan of the University of Seville. Following the guidelines of the European Higher Education Area, the learning experience designed has to enable the future Building Engineers to acquire specific and generic competences ascribed to the Final Project in the Verification Report of the Building Engineering Degree. The specific competence “E71. Presentation and defence before a university board of a final project, consisting of an integration exercise of the formative contents received and skills acquired through t he degree” is trained by the development of a building execution project with the use of BIM technologies. For a decade, architecture and engineering offices have increasingly been incorporating in their projects new tools for information processing in digital integrated systems, i.e. programs which allow the construction of building virtual models in three dimensions, and the identification of their constructive components, providing them with parametric dimensions. The operating capacity of BIM programs is stronger than that of 2D drawing programs, since they can manage and generate all the technical documentation in an integrated way. As far as the generic competences are concerned, the problem is that the Final Project has ascribed twenty four competences and their training and evaluation throughout a single term, which seems rather unattainable. In order to solve this matter, the four most important generic competences of Building Engineers have been identified according to their professional profile: “G01. Capacity for organization and planning”, “G06. Information management skills”, “G09. Ability to work in an interdisciplinary team” and “G13. Positive social attitude towards social and technological innovations”. The use of BIM technologies and collaborative work methodologies allow the training of these genericcompetences. Finally, assessment matrixes of the five competences involved have been established with the descriptors of the assessment indicators for each of their corresponding criteria at each level of student achievement. This study is limited to the design of the experience; its implementation could be carried out in the first term of the 2012/2013 academic year, provided the main pre-requisite are met by students, and command of BIM programs such as ALLPLAN, REVIT or ARCHICAD, is achieved. Aware of this challenge− since BIM programs are taught as optional subjects− a curricular line for students interested in participating in this experience is also proposed for the next academic yea

    Paleoecología del yacimiento del Neógeno continental de Los Valles de Fuentidueña (Segovia)

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    Conclusiones: Los datos geológicos nos indican que las capas excavadas no son homogéneas en cuanto a su deposición, un decrecimiento de la energía del medio se observa de muro a techo, esto se refleja claramente en la tafocenosis cuyo grado de aloctonía disminuye de muro a techo. No parece existir una diferencia cualitativa entre la fauna del Nivel Y (alóctono) y del Nivel X (más autóctono), aunque dada la dificultad de extraer los fósiles de este último nivel, los datos siguientes tienen más fiabilidad para el nivel Y. El estudio de la comunidad fósil nos indica el predominio fuerte de algunas especies, pero su análisis de talla parece contradecir la existencia de factores limitantes en esta comunidad, lo que unido a la reconstrucción geológica del medio, puede indicarnos que el medio de transporte ha sido uno de los factores más selectivos en la acumulación de los fósiles de este yacimiento, sin olvidar, que posiblemente la mayor parte de los restos de los animales habían estado sometidos en un largo periodo a la intemperie después de su muerte; la no existencia de ningún resto en conexión anatómica es concluyente a tal respecto. Podría suponerse un tipo de clima estacional, con al menos dos estaciones contrastadas una seca y otra húmeda que ocasionaría arroyadas como la que ha conformado el yacimiento; dentro de este marco climático poseeríamos, en el entorno alrededor del yacimiento, un ecosistema con nichos ecológicos diferentes. Podemos suponer que la zona alrededor del yacimiento ocupa la transición entre relieve moderado y una llanura de tipo sabana; esta zona de tipo transicional, se caracterizaría por la existencia de charcas efímeras. Cercana a esta zona existirían áreas con aguas limpias más o menos permanentes (de escorrentía y surgencias cársticas) en cuyos alrededores se desarrollaría una vegetación densa, que es la que soporta a un gran número de especies poco abundantes en restos (exceptuando Aceratherium sp.). Es de suponer que la zona de llanura sustentaría las formas gregarias muy abundantes en restos, como es el caso de Hipparion.Peer reviewe

    Strain Effects in Protonated Carbonyl Compounds. An Experimental and ab Initio Treatment of Acyclic Carboxamides and Ketones

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    Strain effects have been quantitatively evaluated for a set of 22 compounds including ketones (R2CO), carboxamides (RCONH2), and N,N-dimethylcarboxamides (RCONMe2), where R = Me, Et, i-Pr, t-Bu, 1-adamantyl (1-Ad), in their neutral and protonated forms. To this end, use was made of the gas-phase proton affinities and standard enthalpies of formation of these compounds in the gas phase, as determined by Fourier transform ion cyclotron resonance mass spectrometry (FT ICR) and thermochemical techniques, respectively. The structures of 1-AdCOMe and (1-Ad)2CO were determined by X-ray crystallography. Quantum-mechanical calculations, at levels ranging from AM1 to MP2/6-311+G(d,p)//6-31G(d), were performed on the various neutral and protonated species. Constrained space orbital variation (CSOV) calculations were carried out on selected protonated species to further assess the contributions of the various stabilizing factors. Taking neutral and protonated methyl ketones as references, we constructed isodesmic reactions that provided, seemingly for the first time, quantitative measures of strain in the protonated species. A combination of these data with the results of theoretical calculations (which also included several “computational experiments”) lead to a unified, conceptually satisfactory, quantitative description of these effects and their physical link to structural properties of the neutral and protonated species.This work was supported by grants PB 93-0289-C02 and PB-93-0142-C03-01 from the Spanish D.G.I.C.Y.T. Work by H.H. was supported by the Moroccan Ministry of Education and C.S.I.C
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