6,104 research outputs found
A Novel Ultrasound-based Measure of the Liver among Diabetes Mellitus Type II Patients
Diabetes mellitus type II (DM II) or adult onset diabetes is due to the inefficient use of insulin, which affects various organs and tissues. Patients with DM II are at risk of suffering non-alcoholic fatty liver disease (NAFLD) that can later develop into more life threating forms such as hepatomegaly, cirrhosis or liver cancer. Following the logic of the non-inferiority trial test, we aim to establish a more accurate anatomical measure of the right liver lobe (RLL) to facilitate close monitoring of liver size with ultrasound (US). We hypothesize that US is not unacceptably worse than computed tomography (CT) or magnetic resonance imaging (MRI) to accurately and reliably measure the size of the RLL when the measure is taken in the midaxillary line and craniocaudal plane (MAL-CC). Therefore, the objective of this study is to conduct a non-inferiority trial to test our novel MAL-CC measure.
To meet this aim, US measure of the RLL was taken from DM II (n=7) and non-DM II (n=5) patients, whom were recruited from 2 endocrinology clinics at SoM-UPR. Preliminary data shows that MAL-CC measure of the RLL from non-DM II patients is 13.99 + 2.53 cm whereas the same measurement among DM II patients is 15.25 + 3.25 cm (Mann-Whitney U test, p= 0.42). It is concluded that there is a non-significant trend for large RLL sizes among DM II patients. Future work aims to increase sample size and to validate our novel measurement with MRI
Origin of peer influence in social networks
Social networks pervade our everyday lives: we interact, influence, and are influenced by our friends and acquaintances. With the advent of the World Wide Web, large amounts of data on social networks have become available, allowing the quantitative analysis of the distribution of information on them, including behavioral traits and fads. Recent studies of correlations among members of a social network, who exhibit the same trait, have shown that individuals influence not only their direct contacts but also friends' friends, up to a network distance extending beyond their closest peers. Here, we show how such patterns of correlations between peers emerge in networked populations. We use standard models (yet reflecting intrinsically different mechanisms) of information spreading to argue that empirically observed patterns of correlation among peers emerge naturally from a wide range of dynamics, being essentially independent of the type of information, on how it spreads, and even on the class of underlying network that interconnects individuals. Finally, we show that the sparser and clustered the network, the more far reaching the influence of each individual will be.Financial support by FEDER through POFC-COMPETE and by FCT-Portugal is gratefully acknowledged through Grants No. SFRH/BD/77389/2011, No. SFRH/BPD/90936/2012, No. PTDC/MAT/122897/2010, No. EXPL/EEI-SII/2556/2013, No. PEst-OE/EEI/LA0021/2013, and No. PEst-OE/BIA/UI4050/2014
Spectroscopic binaries in the Solar Twin Planet Search program: from substellar-mass to M dwarf companions
Previous studies on the rotation of Sun-like stars revealed that the
rotational rates of young stars converge towards a well-defined evolution that
follows a power-law decay. It seems, however, that some binary stars do not
obey this relation, often by displaying enhanced rotational rates and activity.
In the Solar Twin Planet Search program we observed several solar twin
binaries, and found a multiplicity fraction of in the whole
sample; moreover, at least three of these binaries (HIP 19911, HIP 67620 and
HIP 103983) clearly exhibit the aforementioned anomalies. We investigated the
configuration of the binaries in the program, and discovered new companions for
HIP 6407, HIP 54582, HIP 62039 and HIP 30037, of which the latter is orbited by
a M brown dwarf in a 1-month long orbit. We report the orbital
parameters of the systems with well-sampled orbits and, in addition, the lower
limits of parameters for the companions that only display a curvature in their
radial velocities. For the linear trend binaries, we report an estimate of the
masses of their companions when their observed separation is available, and a
minimum mass otherwise. We conclude that solar twin binaries with low-mass
stellar companions at moderate orbital periods do not display signs of a
distinct rotational evolution when compared to single stars. We confirm that
the three peculiar stars are double-lined binaries, and that their companions
are polluting their spectra, which explains the observed anomalies.Comment: 13 pages, 7 figures, accepted for publication in MNRA
Stable leaders pave the way for cooperation under time-dependent exploration rates
Pinheiro, F. L., Pacheco, J. M., & Santos, F. C. (2021). Stable leaders pave the way for cooperation under time-dependent exploration rates. Royal Society Open Science, 8(2), [200910]. https://doi.org/10.1098/rsos.200910The exploration of different behaviours is part of the adaptation repertoire of individuals to new environments. Here, we explore how the evolution of cooperative behaviour is affected by the interplay between exploration dynamics and social learning, in particular when individuals engage on prisoner's dilemma along the edges of a social network. We show that when the population undergoes a transition from strong to weak exploration rates a decline in the overall levels of cooperation is observed. However, if the rate of decay is lower in highly connected individuals (Leaders) than for the less connected individuals (Followers) then the population is able to achieve higher levels of cooperation. Finally, we show that minor differences in selection intensities (the degree of determinism in social learning) and individual exploration rates, can translate into major differences in the observed collective dynamics.publishersversionpublishe
Evolution of the Socio-cognitive Structure of Knowledge Management (1986–2015): An Author Co-citation Analysis
Purpose: The evolution of the socio-cognitive structure of the field of knowledge management (KM) during the period 1986–2015 is described.
Design/methodology/approach: Records retrieved from Web of Science were submitted to author co-citation analysis (ACA) following a longitudinal perspective as of the following time slices: 1986–1996, 1997–2006, and 2007–2015. The top 10% of most cited first authors by sub-periods were mapped in bibliometric networks in order to interpret the communities formed and their relationships.
Findings: KM is a homogeneous field as indicated by networks results. Nine classical authors are identified since they are highly co-cited in each sub-period, highlighting Ikujiro Nonaka as the most influential authors in the field. The most significant communities in KM are devoted to strategic management, KM foundations, organisational learning and behaviour, and organisational theories. Major trends in the evolution of the intellectual structure of KM evidence a technological influence in 1986–1996, a strategic influence in 1997–2006, and finally a sociological influence in 2007–2015.
Research limitations: Describing a field from a single database can offer biases in terms of output coverage. Likewise, the conference proceedings and books were not used and the analysis was only based on first authors. However, the results obtained can be very useful to understand the evolution of KM research.
Practical implications: These results might be useful for managers and academicians to understand the evolution of KM field and to (re)define research activities and organisational projects.
Originality/value: The novelty of this paper lies in considering ACA as a bibliometric technique to study KM research. In addition, our investigation has wider time coverage than earlier articles
Análise comparativa do sistema nacional de colocação de professores em Portugal
A colocação dos professores no ensino secundário em Portugal Ă© efetuada sobre a responsabilidade do MinistĂ©rio da Educação e CiĂŞncia, que Ă© quem define as regras do funcionamento do sistema, ou seja Ă© um sistema centralizado. Esse sistema Ă© alvo de crĂticas por parte dos seus intervenientes sobretudo dos prĂłprios professores. Este artigo tem como objetivo efetuar uma revisĂŁo sistemática e uma meta análise de como sĂŁo efetuadas as colocações de professores em Portugal, bem como noutros paĂses europeu
Modeling the Dashboard Provenance
Organizations of all kinds, whether public or private, profit-driven or
non-profit, and across various industries and sectors, rely on dashboards for
effective data visualization. However, the reliability and efficacy of these
dashboards rely on the quality of the visual and data they present. Studies
show that less than a quarter of dashboards provide information about their
sources, which is just one of the expected metadata when provenance is
seriously considered. Provenance is a record that describes people,
organizations, entities, and activities that had a role in the production,
influence, or delivery of a piece of data or an object. This paper aims to
provide a provenance representation model, that entitles standardization,
modeling, generation, capture, and visualization, specifically designed for
dashboards and its visual and data components. The proposed model will offer a
comprehensive set of essential provenance metadata that enables users to
evaluate the quality, consistency, and reliability of the information presented
on dashboards. This will allow a clear and precise understanding of the context
in which a specific dashboard was developed, ultimately leading to better
decision-making.Comment: 8 pages, 4 figures, one table, to be published in VIS 2023 (Vis +
Prov) x Domai
Recommendations for a new portuguese teacher placement system
Portuguese teacher placements’ system is a centralized system managed by the Portuguese government, specifically by the Ministry of Education and Science. It is a system with some issues and, therefore, has been criticized by its stakeholders, mainly by teachers. This paper aims to do a systematic review and a meta-analysis of the Portuguese teacher placements’ system. An objective is to understand and describe how similar system works in European Union countries. Another objective is to interview school specialists, in this particular case - teachers, to find solutions for teacher placements’ system. Finally, from solutions from European Union countries and from solutions arising from schools’ specialists, a set of requirements is identified that the teacher placements’ system should take into account, in order to avoid the issues identified.This project was funded by Fundo Europeu de Desenvolvimento Regional (FEDER), by Programa Operacional Factores de Competitividade (POFC) - COMPETE and by Fundacao para a Ciencia e Tecnologia, on the Scope of projects: PEstC/EEI/UI0319/2015, PEstC/EEI/UI0027/2015 and POCI-01-0145-FEDER-006961.info:eu-repo/semantics/publishedVersio
Assessment of stiffness and fatigue tests in Portugal
In the last decade, quality control of asphalt mixtures for pavement construction on the main Portuguese national road network used, most of the time, four-point bending beam tests (4pb) results as a reference. Stiffness modulus and fatigue laws established with samples prepared in the laboratory are usually used as a reference for behaviour/quality control analysis of the samples coming from the construction site. There is however, with this procedure, not only a problem of real world representation but also a question of the compatibility of results coming, again most of the time, from different laboratories using different equipments. Trying to address the second problem, this paper presents the results obtained from four-point bending tests carried out in three different laboratories in Portugal, owning three different 4pb equip-ments, concerning the performance characterization of a typical Portuguese base course asphalt mixture. The paper finally discusses the variability of the results obtained and underlines the main inferences that could be extracted
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