14,936 research outputs found
Evaluation of strengthening techniques of traditional masonry buildings: case study of a four-building aggregate
Increasing appraisal of the durability, conservation state, and changeable use and function of old buildings in urban centers relies a great deal on the structural safety evaluation of vertical load capacity and the ability to resist horizontal forces. The need to assess seismic vulnerability, particularly of traditional masonry buildings, is a key issue. Evaluation of the seismic vulnerability of old buildings is essential in the definition of strengthening needs and minimization of damage from seismic actions in the safeguarding of built heritage. A three-dimensional model was developed for an aggregate of four traditional masonry buildings located in the old city center of Coimbra, in Portugal. The finite element modeling of these buildings has aimed to identify structural fragility, understand the damages detected, and evaluate the global structural safety of these types of buildings. The primary results obtained in this case study helped to interpret the structural damage and stress distribution, and verified global stability and its consequences. Different strengthening techniques to improve the global behavior of these buildings were modeled and analyzed. A comparison of the efficiencies of strengthening strategies is also discussed. DOI: 10.1061/(ASCE)CF.1943-5509.0000164. (C) 2011 American Society of Civil Engineers
Demonstration-based help: a case study
The usability of today’s applications is of utmost importance, and to fully achieve it some changes are yet to be adopted. Help systems are part of the applications and allow users to understand it and use it. However, this is one of the fields that some corporates still neglect. Moreover, every system has its characteristics and customizations and being able to explain how something works on a generic but efficient way is a major challenge.
Studies have been conducted and applications, especially on a daily-use context, are still cause of frustration to its users. Contextual and demonstration-based strategies are examples of beneficial approaches to improve the status. Additionally, current technologies like picture-driven computing and automation are enablers facilitating the interaction with “closed” applications, whose source codes are not available, and allowing for the process to be reproduced automatically on any platform.
Our solution deploys fast easy learning. It allows users to learn how to perform tasks by watching them get done on their own system. This was done by the manual creation of picture-driven scripts with the use of a tool named Sikuli.
This paper presents our tool and a preliminary case-study. A preliminary evaluation with users was made and positive results were shown. When tracking metrics relative to a first interaction with a system/realization of a specific tasks, users achieved the goal five times faster with the demonstration-based help tool. On second time executions, the performance from users that used our tool and users that learned through exploration and manual readings were similar, indicating that learning by observation does not detract the learning process.
The solution is now to be implemented in a technology corporation where problematic tasks and platforms will be identified, automation scripts developed, and an evaluation with its employees will be conducted. From this evaluation, the usability of the tool will be measured, as learning improvements and increased task performance will be tracked. The availability to help other users, developing and sharing scripts is also one of the research points.info:eu-repo/semantics/acceptedVersio
The Left-Right SU(3)(L)xSU(3)(R)xU(1)(X) Model with Light, keV and Heavy Neutrinos
We construct a full left-right model for the electroweak interactions based
on the gauge symmetry. The fermion
content of the model is such that anomaly cancellation restricts the number of
families to be a multiple of three. One of the most important features of the
model is the joint presence of three light active neutrinos, three additional
neutrinos at keV mass scale, and six heavy ones with masses
around\textbf{} GeV. They form a well-motivated part of the spectrum
in the sense they address challenging problems related to neutrino oscillation,
warm dark matter, and baryogenesis through leptogenesis.Comment: 11 pages. Small corrections and typos fixed. Accepted for publication
in PR
Exosome-based delivery of RNAi leads to breast cancer inhibition
Breast cancer is currently the most prevalent cancer in the world. It has been reported that hyperactivation and dysregulation of key pathways, such as PI3K/AKT/mTOR (PAM), contributes to the cell's tumorigenesis and resistance to existent therapies. Herein, we sought to uncover the potential of PAM downregulation in a panel of different breast cancer cell lines with different phenotypes, through PIK3CA silencing. This oncogene was targeted with a pre-designed small interfering RNA (siRNA) transfected onto PIK3CA wild-type MDA-MB-231cells and PIK3CA mutated MDA-MB-453cells. The results suggest that the siRNA efficiently targeted PIK3CA, triggering an efficient gene silencing and a decrease on cellular viability, as well as migration capacity. Moreover, exosome-like nanovesicles were successfully isolated, characterized and incorporated into the cells and served as excellent siRNA nanocarriers, promoting an incremented and faster onset. Altogether, the data gathered shows that the combination of the validated siRNA with these nanocarriers could be a promising targeted drug delivery system for an alternative breast cancer therapy.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit. Débora Ferreira is recipient of a fellowship supported by a doctoral advanced training (call NORTE-69-2015-15) funded by the European Social Fund under the scope of Norte2020 - Programa Operacional Regional do Norte. Débora Ferreira also acknowledges “Liga Portuguesa contra o cancro - Núcleo Regional do Norte (LPCC-530 NRN)“ for her fellowship. The authors thank Diana Vilas Boas (CEB/University of Minho) for confocal microscopy technical support.info:eu-repo/semantics/publishedVersio
The role of satisfaction with the performance appraisal: A comparative study between the public and private sectors
Purpose – To study in Portugal (a) whether satisfaction with the performance appraisal (PA) differs depending on the sector where the workers perform their functions (private versus public), and (b) whether the relationship between workers’ perception of usefulness and accuracy of the performance appraisal process (PAP) and satisfaction with the outcome of their last PA is mediated by their satisfaction with the PAP.Theoretical framework – The PA has come to occupy a prominent place in organizations, because only it can be used to measure the skills of their workers and the way they contribute to achieving organizational success both qualitatively and quantitatively.Design/methodology/approach – Eight hundred and sixty-six professionals from the public and private sectors participated in this study. Data were collected using two multi-item questionnaires and two single-item scales.Findings – The results revealed that private sector employees showed higher levels of satisfaction with their PAs than those from the public sector. Furthermore, the results indicated that the usefulness and accuracy of the PAP had a significant and positive relationship with employees’ satisfaction with their last PA, and this relationship was partially mediated by satisfaction with the PAP, both in the public and private sectors.Practical & social implications of research – Regardless of the activity sector, it is fundamental that the PAP is useful and accurate; otherwise it is discredited, which prevents it from fulfilling its purpose and contributes to increasing the levels of worker dissatisfaction.Originality/value – This study clarified the differences that may emerge regarding satisfaction with PAs between the Portuguese public and private sectors. In addition, this is the first national or international study to analyse the aforementioned constructs in an integrated manner.info:eu-repo/semantics/publishedVersio
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