LUIS ADRIAN OLMEDO SILVA - Academia.edu (original) (raw)

Papers by LUIS ADRIAN OLMEDO SILVA

Journal of Clinical Medicine, 2022

Oral submucous fibrosis (OSF) is a chronic progressive condition affecting the oral cavity, oroph... more Oral submucous fibrosis (OSF) is a chronic progressive condition affecting the oral cavity, oropharynx and upper third of the oesophagus. It is a potentially malignant disorder. The authors collated and analysed the existing literature to establish the overall malignant transformation rate (MTR). A retrospective analysis of medical and dental scientific literature using online indexed databases was conducted for the period 1956 to 2021. The quality of the enrolled studies was assessed by the Newcastle-Ottawa Scale (NOS). A meta-analysis using a random effects model of a single proportion was performed along with statistical tests for heterogeneity. The overall proportion of malignancy across all studies was 0.06 (95% CI, 0.02–0.10), indicating an overall 6% risk of malignant transformation across all studies and cohorts. Sub-group analyses revealed strong differences in proportion of malignancy according to ethnicity/cohort; Chinese = 0.02 (95% CI 0.01–0.02), Taiwanese = 0.06 (95% C...

Acta Scientiarum. Biological Sciences, 2021

This study aimed to evaluate the growth of Arthrospira (Spirulina) platensis cultivated in Zarrou... more This study aimed to evaluate the growth of Arthrospira (Spirulina) platensis cultivated in Zarrouk culture medium and effluent from Nile tilapia (Oreochromis niloticus) reared in biofloc system. Four treatments were used: Control (100% Zarrouk), E50 (50% Zarrouk + 50% Tilapia effluent), E75 (25% Zarrouk + 75% Tilapia effluent), and E100 (100% Tilapia effluent), and the experiment lasted 10 days. Growth parameters such as maximum cell density (MCD), doubling time (DT), and growth rate (K) were daily evaluated, as well as pH and water temperature. In addition, the concentrations of total ammonia nitrogen (TAN), nitrite-N (NO2-N), and nitrate-N (NO3-N) were analyzed in order to compare nitrogen absorption. Among treatments, E50 and E75 obtained higher maximum cell densities and presented an exponential growth rate similar to the control treatment. Regarding the concentrations of nitrogen compounds, a significant reduction was observed in all treatments, with an NO3-N uptake of 99%, fol...

Fluids, 2020

The relative importance of the helicity and cross-helicity electromotive dynamo effects for self-... more The relative importance of the helicity and cross-helicity electromotive dynamo effects for self-sustained magnetic field generation by chaotic thermal convection in rotating spherical shells is investigated as a function of shell thickness. Two distinct branches of dynamo solutions are found to coexist in direct numerical simulations for shell aspect ratios between 0.25 and 0.6—a mean-field dipolar regime and a fluctuating dipolar regime. The properties characterising the coexisting dynamo attractors are compared and contrasted, including differences in temporal behaviour and spatial structures of both magnetic fields and rotating thermal convection. The helicity α-effect and the cross-helicity γ-effect are found to be comparable in intensity within the fluctuating dipolar dynamo regime, where their ratio does not vary significantly with the shell thickness. In contrast, within the mean-field dipolar dynamo regime the helicity α-effect dominates by approximately two orders of magni...

Proceedings of the 2nd International Conference on Model-Driven Engineering and Software Development, 2014

This paper presents our approach for producing graphical user interfaces (GUIs) for functionally ... more This paper presents our approach for producing graphical user interfaces (GUIs) for functionally rich business information system (BIS) prototypes, upon a mobile platform. Those prototypes are specified with annotated UML class diagrams. Navigation in the generated GUIs is allowed through the semantic links that match the associations and cardinalities among the conceptual domain entities, as expressed in the model. We start by reviewing the Android scaffolding for producing flexible GUIs for mobile devices. The latter can present rather different displays, in terms of size, orientation and resolution. Then we show how our model-based generative technique allows producing prototypes that match both the Android GUIs requirements, while implementing our model-driven approach for user navigation.

Geophysical & Astrophysical Fluid Dynamics, 2019

Double-diffusive convection driven by both thermal and compositional buoyancy in a rotating spher... more Double-diffusive convection driven by both thermal and compositional buoyancy in a rotating spherical shell can exhibit a rather large number of behaviours often distinct from that of the single diffusive system. In order to understand how the differences in thermal and compositional molecular diffusivities determine the dynamics of thermo-compositional convection we investigate numerically the linear onset of convective instability in a double-diffusive setup. We construct an alternative equivalent formulation of the non-dimensional equations where the linearised double-diffusive problem is described by an effective Rayleigh number, Ra, measuring the amplitude of the combined buoyancy driving, and a second parameter, α, measuring the mixing of the thermal and compositional contributions. This formulation is useful in that it allows for the analysis of several limiting cases and reveals dynamical similarities in the parameters space which are not obvious otherwise. We analyse the structure of the critical curves in this Ra−α space, explaining asymptotic behaviours in α, transitions between inertial and diffusive regimes, and transitions between large scale (fast drift) and small scale (slow drift) convection. We perform this analysis for a variety of diffusivities, rotation rates and shell aspect ratios showing where and when new modes of convection take place.

Movimento (ESEFID/UFRGS), 2010

Este estudo tem como objetivo compreender a participação dos clubes esportivos porto-alegrenses n... more Este estudo tem como objetivo compreender a participação dos clubes esportivos porto-alegrenses na invenção da ‘Corrida de Revezamento do Fogo Simbólico da Pátria’ (CFS) em Porto Alegre (RS – Brasil) no período de 1938 a 1947. Fontes impressas e fontes orais foram utilizadas nesse estudo. Os clubes esportivos porto-alegrenses, na figura dos seus atletas e dirigentes, ajudaram a inventar e fixar a CFS em Porto Alegre. Além disso, os clubes esportivos construíram representações da identidade nacional brasileira através da CFS.

Survey of ophthalmology, Jan 10, 2018

The iridocorneal endothelial syndrome (ICE) represents a unique group of ocular pathologies (Chan... more The iridocorneal endothelial syndrome (ICE) represents a unique group of ocular pathologies (Chandler syndrome, progressive iris atrophy, and Cogan-Reese syndrome) characterized by the proliferation of corneal endothelial cells that migrate toward the iridocorneal angle and iris surface causing, to a degree varying according to the subtype, corneal edema and decompensation, and secondary glaucoma, whether by obstructing the angle or producing peripheral anterior synechiae by contraction of the basement membrane of the migrating cells over the surface of the iris. A triggering factor, possibly viral, induces the corneal endothelial cells to proliferate and behave like epithelial cells. Diagnosis is made based on typical ocular findings on the cornea and iris. ICE is more frequent in young women, with unilateral involvement in most cases. In-vivo confocal microscopy is an excellent diagnostic tool, especially in borderline presentations like early cases of Chandler syndrome, which aff...

PASOS Revista de turismo y patrimonio cultural, 2010

Resumo: A expressão turismo de habitação designa as modalidades de hospedagem em zonas rurais, or... more Resumo: A expressão turismo de habitação designa as modalidades de hospedagem em zonas rurais, orientadas para a exploração dos seus recursos naturais e culturais. Este artigo apresenta dados qualitativos e quantitativos sobre a produção, o consumo e os impactos locais do sector em Portugal. A oferta proporciona dois tipos de alojamento: o que seria típico dos camponeses com algumas posses e o que associamos às elites de província. Existem quatro grupos de proprietários: elites de província, agricultores, indiferenciados e prevaricadores. Os hóspedes são citadinos de classe média movidos por uma sensibilidade pastoral, à qual se junta a atracção pela História quando frequentam solares e casas apalaçadas. O sector não produz efeitos significativos no tecido social e económico das áreas de implantação, mas tem importantes valências simbólicas.

Proceedings of the 2016 CHI Conference on Human Factors in Computing Systems, 2016

Figure 1. Three visualizations of the same dataset (from the game show Jeopardy!), designed to be... more Figure 1. Three visualizations of the same dataset (from the game show Jeopardy!), designed to be of (a) low, (b) high, and (c) middling usability.

Intelligent Transportation Systems, 2016

A huge research effort has been devoted to the transportation sector in order to make it safer an... more A huge research effort has been devoted to the transportation sector in order to make it safer and more efficient, leading to the development of the so-called Intelligent Transportation Systems (ITS). In ITS there is a closed loop interaction between vehicles, drivers and the transportation infrastructure, supported by dedicated networks, usually referred to as vehicular networks. While some of the enabling technologies are entering their mature phase, the communication protocols proposed so far aren’t able to fulfill the timeliness contraints of many ITS services, specially in road congestion scenarios. In order to tackle this issue, several medium access protocols (MAC), either relying on infrastructure or based on direct ad-hoc communication, have been designed. A great number of these protocols employ Time Division Multiple Access (TDMA) techniques to manage communications and attain some degree of determinism. Although the use of spatial reuse algorithms for TDMA protocols (STDMA) has been extensively studied as to increase the efficiency of standard ad-hoc and mesh networks, ITS networks exhibit a combination of features and requirements that are unique and aren’t addressed by these algorithms. This chapter (This chapter is an extended work of [21]) discusses some of the most relevant challenges in providing deterministic real-time communications in ITS vehicular networks as well as the efforts that are being taken to tackle them. Focus on TDMA infrastructure-based protocols and on the challenges of employing spatial reuse methods in vehicular environments is placed. A novel wireless vehicular communication architecture called V-FTT, which aims at providing deterministic communications in vehicular networks, is also presented. The chapter concludes with the design of a traffic scheduling analysis, a STDMA slot assignment algorithm and a Matlab simulator for V-FTT.

Resumo A expressão Turismo em Espaço Rural (TER) designa o conjunto de modalidades de hospedagem ... more Resumo A expressão Turismo em Espaço Rural (TER) designa o conjunto de modalidades de hospedagem em zonas rurais, orientadas para exploração dos seus recursos naturais e culturais. A criação deste tipo de alojamento turístico insere-se nas medidas adoptadas pelo Estado português e pela União Europeia para inverter a crise gerada pela desruralização do país iniciada por volta de 1960. Este artigo analisa os impactos que estas unidades de alojamento turístico têm no território nacional e nas povoações de Estorãos (Ponte de Lima), Sortelha (Sabugal) e Monsaraz (Reguengos de Monsaraz). A informação apurada indica que este tipo de turismo não se repercute de modo significativo no tecido socio-económico das áreas em que é implantado, contrariando os argumentos dos profissionais do sector. É na esfera simbólica que reside a mais-valia do TER, cuja existência contribui para a manutenção do campo enquanto suporte de identidade nacional. Palavras-Chave Turismo em espaço rural (TER); desenvolvimento rural; campo.

Le tunnel de Trofa, au nord du Portugal, d'une longueur de 1519 m s'insere dans le projet... more Le tunnel de Trofa, au nord du Portugal, d'une longueur de 1519 m s'insere dans le projet de rehabilitation et deviation vers le centre-ville du reseau ferroviaire, afin d'ameliorer la liaison avec la ville de Porto. Mille quatre-vingt-dix metres sont construits en souterrain, et 429 m en construction traditionnelle (galeries recouvertes - murs de soutenement - talus). La methodologie d'excavation comprend l'utilisation de moyens mecaniques (attaque ponctuelle et pelle hydraulique avec fraise et BRH) pour traverser un massif schisteux de moyenne qualite. Le contrat a ete remis le 29 janvier 2008, aux entreprises Soares da Costa et Spie batignolles europe, pour une duree de deux ans et un montant de 15726000,00 euros.

Qatar Foundation Annual Research Forum Proceedings, 2012

In the near future Qatar will be a country of many museums, but already many temporary exhibition... more In the near future Qatar will be a country of many museums, but already many temporary exhibitions are open to the public. The International Council of Museums defines museums as an institution which acquires, conserves, researches, communicates and exhibits for the purposes of education, study and enjoyment. The question of whether a sports museum is a place for scientific research has already been raised. The on-going discussion is about how to accomplish this. As a contribution, this article aims to examine the practical use of research in museums based on the "Arab Games Exhibition" (AGE), which was developed by the Qatar Olympic & Sports Museum in Doha, Qatar in 2011. The AGE showcased the history of these Games from their first edition until its last. Lacking a comprehensive body of reliable secondary literature and information on the whereabouts of possible artifacts, it was necessary to develop an extensive research project to find written and oral sources, and then objects to exhibit. Thus, the whole exhibition concept was based on the findings of the developed research. The primary sources used in the research were the documents displayed in the exhibition, which reinforces the idea that the museum collections function as a primary source for research. The sports museum's collections are usually sport artifacts and memorabilia preserved to document the phenomenon. Therefore, research sources and collections are interconnected. In addition to the scarce written sources, the memories of athletes were recorded. These interviews were presented audio-visually for the exhibition, 'giving a voice' to the athletes and explored the appeal of audio-visual exhibits to the public. Naturally, these interviews have become part of the museum collection, being preserved for future exhibitions and research. The example of the AGE illustrates the uses of research in museums. The museum collections can be considered as 'archives' of sources for socio-cultural studies. Furthermore, the exhibitions and the educational programs can be considered the 'space' where the knowledge developed through research is reinterpreted to showcase the complexity of the sport phenomenon to the public.

Proceedings of SPIE - The International Society for Optical Engineering, 2001

In the Mobile Agent programming model, small threads of execution migrate from machine to machine... more In the Mobile Agent programming model, small threads of execution migrate from machine to machine, performing their operations locally. For being able to deploy such a model into real world applications, security is a vital concern. In the M&M project we have developed a system that departures from the traditional platform-based execution model for mobile agents. In M&M there are no agent platforms. Instead there is a component framework that allows the applications to become able of sending and receiving agents by themselves in a straightforward manner. In this paper we examine the security mechanisms available in M&M, and how integration with existing applications is done. One difficult aspect of this work is that all the features must work with the security mechanisms that already exist on the applications. This is so because the components are integrated from within into the applications, which already have security mechanisms in place. Currently, M&M provides features like fine-grain security permissions, encryption of agents and data, certificate distribution using LDAP and cryptographic primitives for agents. For validating the approach and solutions found, we have integrated the framework into several off-the-shelf web servers, having the security mechanisms running, with no problems.

2011 IEEE International Symposium on Parallel and Distributed Processing Workshops and Phd Forum, 2011

Volunteer Computing harnesses computing resources of machines from around the world to perform di... more Volunteer Computing harnesses computing resources of machines from around the world to perform distributed independent tasks, following a master/worker model. Despite the recent increase in popularity and power in middleware such as BOINC, there are still several limitations in existing systems. Current research is oriented towards optimizing existing applications, while the number of active users and projects has reached a plateau. A programming paradigm that has been significantly popular and is used by several systems on the cloud is MapReduce. The main advantage of this paradigm is that it can be used to solve a vast amount of different problems, by breaking them into simple steps and taking advantage of distributed resources. Volunteer Computing provides these resources, and although it cannot match the conditions offered by a cluster, it has other advantages that can be leveraged. In this paper, we try to increase the computational power of Volunteer Computing systems by allowing more complex applications and paradigms such as MapReduce to be run, thus opening new avenues and possibilities for the use of computational devices scattered through the Internet. We created a BOINC prototype that can run MapReduce jobs (BOINC-MR), using a pull-model in which communication is always initiated by the client. By running experiments on a small cluster, with multiple variables, we were able to evaluate a few initial scenarios with this paradigm. We used a simple MapReduce application, word count, as proof of concept, just to demonstrate a typical execution.

Molecules (Basel, Switzerland), Jan 22, 2014

This study aimed to evaluate the anti-allergic potential of Echium plantagineum L. bee pollen and... more This study aimed to evaluate the anti-allergic potential of Echium plantagineum L. bee pollen and to characterize its primary metabolites. The activity of E. plantagineum hydromethanolic extract, devoid of alkaloids, was tested against β-hexosaminidase release in rat basophilic leukemic cells (RBL-2H3). Two different stimuli were used: calcium ionophore A23187 and IgE/antigen. Lipoxygenase inhibitory activity was evaluated in a cell-free system using soybean lipoxygenase. Additionally, the extract was analysed by HPLC-UV for organic acids and by GC-IT/MS for fatty acids. In RBL-2H3 cells stimulated either with calcium ionophore or IgE/antigen, the hydromethanolic extract significantly decreased β-hexosaminidase release until the concentration of 2.08 mg/mL, without compromising cellular viability. No effect was found on lipoxygenase. Concerning extract composition, eight organic acids and five fatty acids were determined for the first time. Malonic acid (80%) and α-linolenic acid (2...

Environmental Microbiology Reports, 2015

Competitive Transformation of the Postal and Delivery Sector, 2003

In the European Union (EU) the retention of the postal universal service and the continued financ... more In the European Union (EU) the retention of the postal universal service and the continued financial viability of at least one universal service provider (USP) in each state is a statutory requirement. In each European state there is currently only one postal USP.

The International Journal of the History of Sport, 2012

ABSTRACT This paper is the academic result of research conducted by the Qatar Olympic & S... more ABSTRACT This paper is the academic result of research conducted by the Qatar Olympic & Sports Museum into the history of the Arab Games in preparation for The Arab Games Exhibition which took place in Doha, Qatar from October 5 until December 23, 2011. This paper aims to understand the establishment of the Arab Games and their role as Regional Games during the Pan-Arab movement in the 1950s and 1960s. Analysing the historical context of the first four Arab Games (Alexandria 1953, Beirut 1957, Casablanca 1961 and Egypt 1965), the paper follows the hypothesis that the first Arab Games strengthened the bonds of Arab identity and created a representation of an imagined community.