7,453 research outputs found

    Tycho: Facilitation Support for Groupware User Tests

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    Running user tests for groupware requires tracking the progress of multiple users performing co-dependent tasks, while facilitating and observing their coordinated actions. This requirement negatively impacts the main objective of user testing, which is detecting usability flaws. User testing of groupware becomes more challenging when run remotely. Even if there are tools for remote user testing that can get the job done for a single user, they are not prepared for collaborative scenarios. In this paper we argue that tool support for the facilitation of user tests of groupware is missing. Consequently, we propose a method for user tests with tool assistance that makes it possible to automate task synchronization, especially for different workflows that must be run concurrently. We evaluated our proposal by comparing it to a manually facilitated approach during on-site coordinated user tests. The results indicate that, while the task of designing and running user tests with tool support takes more time, it allows the testers to better focus on detecting usability problems.Fil: Grigera, Julián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Informática. Laboratorio de Investigación y Formación en Informática Avanzada; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Gardey, Juan Cruz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Informática. Laboratorio de Investigación y Formación en Informática Avanzada; ArgentinaFil: Fernandez, Alejandro. Universidad Nacional de La Plata. Facultad de Informática. Laboratorio de Investigación y Formación en Informática Avanzada; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Garrido, Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Informática. Laboratorio de Investigación y Formación en Informática Avanzada; Argentin

    Microbial diversity dynamics in a methanogenic-sulfidogenic UASB reactor

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    In this study, the long-term performance and microbial dynamics of an Upflow Anaerobic Sludge Blanket (UASB) reactor targeting sulfate reduction in a SOx emissions treatment system were assessed using crude glycerol as organic carbon source and electron donor under constant S and C loading rates. The reactor was inoculated with granular sludge obtained from a pulp and paper industry and fed at a constant inlet sulfate concentration of 250 mg S-SO42−L−1 and a constant C/S ratio of 1.5 ± 0.3 g Cg−1 S for over 500 days. Apart from the regular analysis of chemical species, Illumina analyses of the 16S rRNA gene were used to study the dynamics of the bacterial community along with the whole operation. The reactor was sampled along the operation to monitor its diversity and the changes in targeted species to gain insight into the performance of the sulfidogenic UASB. Moreover, studies on the stratification of the sludge bed were performed by sampling at different reactor heights. Shifts in the UASB performance correlated well with the main shifts in microbial communities of interest. A progressive loss of the methanogenic capacity towards a fully sulfidogenic UASB was explained by a progressive wash-out of methanogenic Archaea, which were outcompeted by sulfate-reducing bacteria. Desulfovibrio was found as the main sulfate-reducing genus in the reactor along time. A progressive reduction in the sulfidogenic capacity of the UASB was found in the long run due to the accumulation of a slime-like substance in the UASB

    Nuevas ecuaciones de cubicación para pino silvestre en "aguas vertientes" (El Espinar, Segovia).

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    El monte "Aguas Vertientes" (El Espinar) es el nº 138 del C.U.P. de Segovia. Se trata de una masa natural de pino silvestre, con abundante melojo en sus cotas inferiores. Su primer Proyecto de Ordenación fue redactado en 1904, estando actualmente redactada y en fase de aprobación la novena revisión. La madera de pino obtenida es elaborada en un aserradero cercano, perteneciente a la misma entidad propietaria. Durante los últimos años los responsables de dicho aserradero vienen manifestando que la cubicación en pie realizada por la administración forestal presenta errores de magnitud suficiente como para ser necesaria su corrección. Este trabajo fin de carrera ha consistido en comprobar la fiabilidad de los valores modulares empleados hasta ahora, y elaborar nuevas ecuaciones de cubicación. Para ello se ha manejado una muestra de 234 pinos repartidos en malla cuadrada y cubicados en pie mediante el método de Pressler-Bitterlich. Como resultado, se propone una ecuación de doble entrada (función de diámetro normal y altura) para todo el monte; y una ecuación de una entrada (función de diámetro normal) para cotas superiores e inferiores a 1.500 m. Los nuevos modelos son validados mediante una muestra independiente

    Structural basis of the allergenicity to strawberries due to Fra a 1.02

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    Strawberry fruits are highly valued due to their flavor, aroma, and benefits for human health. Despite this, 30% of the population with food hypersensitivity also shows adverse reactions to strawberry (Franz-Oberdorf et al, 2016). The FaFra a 1 protein family, homologs of the major birch pollen allergen Bet v 1, is involved in this allergenicity to strawberry. By RNAseq we have identified transcripts for 18 members of the FaFra a 1 family (from 1.01 to 1.18) in strawberry fruits. Although expressed in all tissues analyzed, each family member presents a unique pattern of expression, which suggests functional specialization for each FaFra a 1 protein. FaFra a 1.02 (Fra2 from now on) is the most expressed one in red fruits and is also the most allergenic among the family members tested (Muñoz et al. 2010; Franz- Oberdorf et al, 2016). In order to understand the molecular bases of this allergenicity we crystalized Fra2 and obtained its structure by X-ray diffraction. Fra2 showed a very high structural homology to Bet v 1, and we asked whether the two proteins were recognized by the immune system in a similar way. For this, we generated five different mutant versions of Fra2 in sites described as important for allergenicity in Bet v 1 (Fernandes et al, 2016), and studied their potential allergenicity as well as their crystal structures. Three of the mutants had substitutions in loop 4 (E46R, D48R, E46/48A) and the other two facing the cavity (A141F and Q64W). Compared to Fra2, all the mutants showed a significant reduction in their capacity to be recognized by the serum of patients with allergies to Bet v 1, and their crystal structures revealed conformational changes in the Bet v 1- IgG interaction sites. Together, these results support that Fra2 and Bet v 1 have similar allergenic determinants We hope this research will aid in understanding how human IgGs interact with Fra2 and might help in the development of new cultivars with a lesser allergenic potential.Grants BIO2013-44199R and BES-2014-068723 (MINECO). The authors also acknowledge the support by the Plan Propio from University of Malaga, Campus de Excelencia Internacional de Andalucía

    Association between Family Dysfunction and Post-Traumatic Stress Disorder in School Students during the Second COVID-19 Epidemic Wave in Peru

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    "Although the effect of the COVID-19 pandemic on children and adolescents’ mental health has been studied, there is still scarce evidence of the influence of nuclear family on the development of post-traumatic stress disorder (PTSD). This study aimed to determine the association between family dysfunction and PTSD in Peruvian high-school students during the COVID-19 pandemic. A cross-sectional study was conducted using a virtual survey administered to 562 high-school students in three schools in Chiclayo, Peru. The dependent variable was PTSD, which was measured with the Child PTSD Symptom Scale. Family dysfunction was the main independent variable, measured with the Family APGAR Questionnaire. Prevalence ratios (PR) and 95% confidence intervals (95% CI) were estimated with generalized linear models. Most of the students were female (88.3%) and the average age was 14.4 years. We found that 21.4% showed severe family dysfunction and 60.3% had PTSD. Students with mild and moderate family dysfunction had 37% (PR: 1.37; 95% CI: 1.14–1.65) and 26% (PR: 1.26; 95% CI: 1.04–1.54) higher PTSD prevalence, respectively. In conclusion, family dysfunction may influence the development of PTSD in adolescents. This study suggests the importance to develop a healthy family environment to help adolescents face critical situations experienced during the pandemic.

    Exploring the performance limits of a sulfidogenic UASB during the long-term use of crude glycerol as electron donor

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    SOx contained in flue gases and S-rich liquid effluents can be valorized to recover elemental sulfur in a two-stage bioscrubbing process. The reduction of sulfate to sulfide is the most crucial stage to be optimized. In this study, the long-term performance of an up-flow anaerobic sludge blanket (UASB) reactor using crude glycerol as electron donor was assessed. The UASB was operated for 400 days with different sulfate and organic loading rates (SLR and OLR, respectively) and a COD/S-SO42− ratio ranging from 3.8 g O2 g−1 S to 5.4 g O2 g−1 S. After inoculation with methanogenic, granular biomass, the competition between sulfate-reducing and methanogenic microorganisms determined to what extent dissolved sulfide and methane were produced. After the complete washout of methanogens, which was revealed by next-generation sequencing analysis, the highest S-EC was reached in the system. The highest average sulfate elimination capacity (S-EC = 4.3 kg S m−3d−1) was obtained at a COD/S-SO42− ratio of 5.4 g O2 g−1 S and an OLR of 24.4 kg O2 m−3d−1 with a sulfate removal efficiency of 94%. The conversion of influent COD to methane decreased from 12% to 2.5% as the SLR increased while a large fraction of acetate (35% of the initial COD) was accumulated. Our data indicate that crude glycerol can promote sulfidogenesis. However, the disappearance of methanogens in the long-term due to the out competition by sulfate reducing bacteria, lead to such large accumulation of acetate

    Design and Analysis of Conformal Antenna for Future Public Safety Communications: Enabling Future Public Safety Communication Infrastructure

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    Future 4G wireless communication systems include, in their capabilities portfolio, emergency-specific needs, such as data support, broadband communication, and extremely high reliability. An emergency situation can be addressed with undoubtedly more chances of success if augmented information is enabled within the public safety communication novel capabilities. In this article, for a fully augmented information provision based on broadband transmission, a user-end (UE) communication-capabilities enhancement is addressed by deploying multiple antennas without compromising the portability and light weight of first-responder equipment. With this aim, we propose the design of a 4.9-GHz conformal antenna array at the rescuer side (integrated in a helmet) and evaluate its performance in terms of relative data rate gain. The conformal array design is based on traditional patch antennas that consider the need for deployment over an ellipsoidal surface. The antenna array is simulated and then built, and several parameter characterizations (bandwidth, radiation pattern, reflection coefficient, and MC) and measurements are undertaken to ensure the suitability of the design. Furthermore, an analysis of the specific absorption rate (SAR) is performed to guarantee that the exposure to electromagnetic fields is below the standardized levels.The authors would like to thank Prof. Eva Rajo-Iglesias from Universidad Carlos III de Madrid. This work has been partly funded by the Spanish Government through projects CIES (RTC-2015-4213-7), MIMOTEX (TEC2014-61776-EXP) and TERESAADA (TEC2017-90093-C3-2-R) (MINECO/AEI/FEDER, UE

    Las comunidades medievales de villa y tierra:¿Una analogía válida para la Protohistoria Final?

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    The social mechanisms that articulated Iron Age societies are still difficult to understand. In the last decades, the traditional pyramidal models have been questioned by different authors who advocate for the diversity of Iron Age societies and the heterogeneity of potential forms of social configuration. Crucial for most of the debates is the use of analogies, with some authors who favour historical sources from medieval Europe and others who privilege ethnographical examples from outside the European continent. While we consider both approaches legitimate, in this paper we present the example of the medieval “town and land” communities, in particular the case of Soria. These communities show a model of kinship relationships, based on transversal organisational structures, which can help us understand the ties and connections between the inhabitants of a landscape according to their origins, place of residence or family. Thus, we argue that the town and land community from Soria can serve as a useful analogy, although not a direct comparison, in order to conceptualise the interrelationships between the urban and rural areas, as well as for examining the simultaneous structuration of social groups around the principles of kinship and territoriality in a context of emerging urbanisation

    Hybrid Composite-Metal Stack Drilling with Different Minimum Quantity Lubrication Levels

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    Hybrid stack drilling is a very common operation used in the assembly of high-added-value components, which combines the use of composite materials and metallic alloys. This process entails the complexity of machining very dissimilar materials, simultaneously, on account of the interactions that are produced between them, during machining. This study analyzed the influence of Minimum Quantity Lubrication (MQL) on the performance of diamond-coated carbide tools when drilling Ti/carbon fiber reinforced plastics (CFRP)/Ti stacks. The main wear mechanism observed was diamond-coating detachment, followed by fragile breaks in the main cutting-edge. The tests done with the lower lubrication levels have shown an important adhesion of titanium (mainly on the secondary cutting-edge) and a higher friction between the tool and the workpiece, producing higher temperatures on the cutting region and a thermal softening effect on the workpiece. These phenomena affect the evolution of cutting power consumption with tool wear in the titanium layer. Regarding the quality of the test specimen, no significant differences were observed between the lubrication levels tested.The authors acknowledge the financial support of Airbus Defense and Space, through the project Drilling Processes Improvement for Multi Material CFRP-Al-Ti Stacks, and the Ministry of Economy and Competitiveness of Spain through the grant PTA2015-10741-I and the project DPI2017-89197-C2-1-

    Influence of cutting parameters on tool wear and hole quality in composite aerospace components drilling

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    Composite Fiber Reinforced Plastics (CFRP) are characterized by their outstanding mechanical properties combined with reduced density and good resistance to corrosion and fatigue which make them suitable for aerospace components. During assembly procedures, one shoot drilling operations, usually including countersinking cycle, are required to minimize positional errors, enhance tight tolerances and reduce process time. Countersink drill bits were tested on CFRP test specimens, representative of aircraft components. Along testing, tool wear was monitored with an optical microscope to track its evolution and determine the dominant wear mechanism. On the other hand, hole quality was evaluated since tool life criterion is based on the assessment of machined surface quality. The influence of cutting speed and feed was analyzed with the objective of looking for extended tool life and more productive cutting parameters. The information gathered from monitoring tool wear and inspecting hole quality can be used for the enhancement of CFRP drilling and the improvement of the manufacturing process competitiveness, in terms of production cost and time.The authors acknowledge the financial support to AIRBUS DEFENCE AND SPACE through the project DRILLING PROCESSES IMPROVEMENT FOR MULTI MATERIAL CFRP-AL-TI STACKS and to the Ministry of Economy and Competitiveness of Spain through the grant with reference PTA2015-10741-I
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