Magnetic states and optical properties of single-layer carbon-doped hexagonal boron nitride

We show that carbon-doped hexagonal boron nitride (h-BN) has extraordinary properties with many possible applications. We demonstrate that the substitution-induced impurity states, associated with carbon atoms, and their interactions dictate the electronic structure and properties of C-doped h-BN. Furthermore, we show that stacking of localized impurity states in small C clusters embedded in h-BN forms a set of discrete energy levels in the wide gap of h-BN. The electronic structures of these C clusters have a plethora of applications in optics, magneto-optics, and opto-electronics

A pilot empirical study of applying a usability technique in an open source software project

Context: The growth in the number of non-technical open source software (OSS) application users and the escalating use of these applications have redoubled the need for, and interest in, developing usable OSS. OSS communities are unclear about which techniques to use in each development process activity. Objective: The aim of our research is to adapt a usability technique (visual brainstorming) to an OSS project and evaluate the feasibility of its application. Method: We used the case study research method to investigate technique application and participation in a project. To do this, we participated as volunteers in the HistoryCal project. Results: We identified adverse conditions that were an obstacle to technique application (like it was not easy to recruit OSS users to participate) and modified the technique to make it applicable. Conclusion: We conclude that these changes were helpful for applying the technique using web artifacts like blogsThis research was funded by the SENESCYT , Quevedo State Tech- nical University, TIN2014-52129-R and TIN2014-60490-P projects and the e-Madrid project (S2013/ICE-2715

Radiation tolerance of nanocrystalline ceramics: insights from Yttria Stabilized Zirconia.

Materials for applications in hostile environments, such as nuclear reactors or radioactive waste immobilization, require extremely high resistance to radiation damage, such as resistance to amorphization or volume swelling. Nanocrystalline materials have been reported to present exceptionally high radiation-tolerance to amorphization. In principle, grain boundaries that are prevalent in nanomaterials could act as sinks for point-defects, enhancing defect recombination. In this paper we present evidence for this mechanism in nanograined Yttria Stabilized Zirconia (YSZ), associated with the observation that the concentration of defects after irradiation using heavy ions (Kr(+), 400 keV) is inversely proportional to the grain size. HAADF images suggest the short migration distances in nanograined YSZ allow radiation induced interstitials to reach the grain boundaries on the irradiation time scale, leaving behind only vacancy clusters distributed within the grain. Because of the relatively low temperature of the irradiations and the fact that interstitials diffuse thermally more slowly than vacancies, this result indicates that the interstitials must reach the boundaries directly in the collision cascade, consistent with previous simulation results. Concomitant radiation-induced grain growth was observed which, as a consequence of the non-uniform implantation, caused cracking of the nano-samples induced by local stresses at the irradiated/non-irradiated interfaces

Enriching Requirements Analysis with the Personas Technique

A thorough understanding of the users that interact with the system is necessary to develop usable systems. The Personas technique developed by the human-computer interaction (HCI) discipline gathers data about users, gains an understanding of their characteristics, defines fictitious personas based on this understanding and focuses on these personas throughout the software development process. The aim of our research is to build Personas into systems development following software engineering (SE) guidelines. The benefits to be gained are an understanding of the user which is not traditionally taken into account in SE. To do this, we had to undertake two types of tasks. First, we modified the Personas technique to conform to the levels of systematization common in SE. We have called the modified technique PersonaSE. Second, we incorporated the proposed technique into the software requirements analysis proces

Diferencias entre las Actividades de Mantenimiento en los Procesos de Desarrollo Tradicional y Open Source

Antecedentes. La creciente importancia del Open Source Software (OSS) ha llevado a los investigadores a estudiar cómo los procesos OSS difieren de los procesos de la ingeniería del software tradicional. Objetivo. Determinar las diferencias y similitudes entre las actividades del proceso de mantenimiento seguido por la comunidad OSS y el establecido por el estándar IEEE 1074:2006. Método. Para conocer las actividades que conforman el proceso de desarrollo OSS realizamos un Systematic Mapping Study. Posteriormente, realizamos un emparejamiento entre las actividades del estándar IEEE 1074:2006 con las actividades del proceso OSS. Resultados. Encontramos un total de 22 estudios primarios. De estos estudios, el 73% contaba con actividades relacionadas con el proceso de mantenimiento. Conclusiones. El proceso de mantenimiento tradicional del software no encaja con lo que ocurre en la comunidad OSS. En su lugar, puede ser mejor caracterizar la dinámica general de la evolución OSS como reinvención. Esta reinvención emerge continuamente de la adaptación, aprendizaje, y mejora de las funcionalidadess y calidad del OSS. Los proyectos OSS evolucionan a través de mejoras menores donde participan tanto usuarios como desarrolladores

Adapting usability techniques for application in open source Software: A multiple case study

Context: As a result of the growth of non-developer users of OSS applications, usability has over the last ten years begun to attract the interest of the open source software (OSS) community. The OSS community has some special characteristics (such as worldwide geographical distribution of both users and developers and missing resources) which are an obstacle to the direct adoption of many usability techniques as specified in the human-computer interaction (HCI) field. Objective: The aim of this research is to adapt and evaluate the feasibility of applying four usability techniques: user profiles, personas, direct observation and post-test information to four OSS projects from the viewpoint of the development team. Method: The applied research method was a multiple case study of the following OSS projects: Quite Universal Circuit Simulator, PSeInt, FreeMind and OpenOffice Writer. Results: We formalized the application procedure of each of the adapted usability techniques. We found that either there were no procedures for adopting usability techniques in OSS or they were not fully systematized. Additionally, we identified the adverse conditions that are an obstacle to their adoption in OSS and propose the special adaptations required to overcome the obstacles. To avoid some of the adverse conditions, we created web artefacts (online survey, wiki and forum) that are very popular in the OSS field. Conclusion: It is necessary to adapt usability techniques for application in OSS projects considering their idiosyncrasy. Additionally, we found that there are obstacles (for example, number of participant users, biased information provided by developers) to the application of the techniques. Despite these obstacles, it is feasible to apply the adapted techniques in OSS projectsThis research was funded by the Secretariat of Higher Education, Science, Technology and Innovation (SENESCYT) of the Government of Ecuador as part of an academic scholarship granted for postgradu- ate training, and Quevedo State Technical University through doctoral scholarships for university professors. Also this research was funded by the Spanish Ministry of Education, Culture and Sports FLEXOR ( TIN2014-52129-R ) and TIN2014-60490-P projects and the eMadrid- CM project ( S2013/ICE-2715 ). Finally, this research received funding from the University of Atacama “DIUDA 22316 ”projec

Applying a Usability Technique in the Open Source Software Development Process: Experiences from the Trenches

The growth in the number of non-developer open source software (OSS) application users has drawn attention to usability in the OSS community. OSS communities do not generally know how to apply usability techniques and are unclear about which techniques to use in each activity of the development process. The aim of our research is to determine the feasibility of applying the focus groups technique in the OSS ERMaster project. To do this, we participated as project volunteers. We used the case study research method to investigate technique application and OSS community participation. As a result, we identified adverse conditions that were an obstacle to the application of the original technique. We then adapted the technique to make it applicable in an OSS project. We can conclude that was not easy to recruit OSS users and developers to participate in technique application

A systematic mapping study on integration proposals of the personas technique in agile methodologies

Agile development processes are increasing their consideration of usability by integrating various user‐centered design techniques throughout development. One such technique is Personas, which proposes the creation of fictitious users with real preferences to drive application design. Since applying this technique conflicts with the time constraints of agile development, Personas has been adapted over the years. Our objective is to determine the adoption level and type of integration, as well as to propose improvements to the Personas technique for agile development. A systematic mapping study was performed, retrieving 28 articles grouped by agile methodology type. We found some common integration strategies regardless of the specific agile approach, along with some frequent problems, mainly related to Persona modelling and context representation. Based on these limitations, we propose an adaptation to the technique in order to reduce the creation time for a preliminary persona. The number of publications dealing with Personas and agile development is increasing, which reveals a growing interest in the application of this technique to develop usable agile softwareThis research was funded by the Spanish Ministry of Science, Innovation and Universities research grant PGC2018-097265-B-I00, MASSIVE project (RTI2018-095255-B-I00) and by EIT-Health, grant number 19091 (POSITIVE project). This research was also supported by the Madrid Region R&D programme (project FORTE, P2018/TCS-4314

Cyclotron motion in graphene

We investigate cyclotron motion in graphene monolayers considering both the full quantum dynamics and its semiclassical limit reached at high carrier energies. Effects of zitterbewegung due to the two dispersion branches of the spectrum dominate the irregular quantum motion at low energies and are obtained as a systematic correction to the semiclassical case. Recent experiments are shown to operate in the semiclassical regime.Comment: 6 pages, 1 figure include

Risperidone-induced weight gain is mediated through shifts in the gut microbiome and suppression of energy expenditure

AbstractRisperidone is a second-generation antipsychotic that causes weight gain. We hypothesized that risperidone-induced shifts in the gut microbiome are mechanistically involved in its metabolic consequences. Wild-type female C57BL/6J mice treated with risperidone (80μg/day) exhibited significant excess weight gain, due to reduced energy expenditure, which correlated with an altered gut microbiome. Fecal transplant from risperidone-treated mice caused a 16% reduction in total resting metabolic rate in naïve recipients, attributable to suppression of non-aerobic metabolism. Risperidone inhibited growth of cultured fecal bacteria grown anaerobically more than those grown aerobically. Finally, transplant of the fecal phage fraction from risperidone-treated mice was sufficient to cause excess weight gain in naïve recipients, again through reduced energy expenditure. Collectively, these data highlight a major role for the gut microbiome in weight gain following chronic use of risperidone, and specifically implicates the modulation of non-aerobic resting metabolism in this mechanism