Attitude and emotions of young Portuguese tourists toward international risk destinations.

The main goals of this ongoing study are to learn about attitude of young Portuguese tourists about risk destinations and their emotions about traveling out of the country.info:eu-repo/semantics/acceptedVersio

On dynamic analysis of contact problems with freeform surfaces : a knee joint 3D-study

One of the biomechanical roles of the knee joint is to withstand high loading forces. Thus, this articulation is quite susceptible to injuries and diseases, which may cause anomalous contact loads, asymmetrical gait patterns and local pain that, ultimately, leads to a knee replacement. In view of that, identifying and quantifying the loads placed on the human knee is critical for understanding realistic joint mechanics. Since there is no standard non-invasive experimental approach able to measure in vivo knee dynamic loads, such quantities have to be predicted by making use of computational methods. The efficiency of these computational methods is a primary concern for a contact formulation to be used in multibody system (MBS) dynamics. In fact, it has been recognized by many researchers that most of the time consumed in simulating contact phenomena is spent on the contact detection phase. This computational time motivated the development of an efficient methodology to predict the contact forces that is here presented.Fundação para a Ciência e a Tecnologia (FCT) - DACHOR (MIT-Pt/BSHHMS/ 0042/2008), BIOJOINTS (PTDC/EME-PME/ 099764/2008), SFRH/BD/40164/ 2007, SFRH/BD/47750/200

A study on dynamics of mechanical systems including joints with clearance and lubrication

In this work a methodology for the dynamical analysis of mechanical systems considering realistic joint characteristics, namely, joints with clearance and lubrication is presented. For the case of the joints with clearance modelled as a contact pair with dry contact, a technique using a continuous approach for the evaluation of the contact force is applied, in which the energy dissipation in form of hysteresis damping is considered. The friction forces are calculated using a modified Coulomb’s friction law. For the lubricated case, the hydrodynamic theory for dynamically loaded journal–bearings is used to compute the forces generated by lubrication action. The numerical results point out that the existence of dry joint clearances causes high peaks on the kinematic and dynamic system’s characteristics due to contact–impact forces when compared to those obtained with lubricated model. The performance of the lubricated joint is closer to that of an ideal joint.FEDER - Project POCTI/2001/EME/38281Fundação para a Ciência e a Tecnologia (FCT

Identifying cognitive abilities to improve CS1 outcome

Introductory programming courses entail students’ high failure and dropout rates. In an effort to tackle this problem, we carried out a qualitative study aiming to shed some light on the programming phase that is most challenging for students, in order to elicit the specific difficulties they experience while learning to program. In doing so, distinctive cognitive abilities, differentiating subjects in terms of the way they handle programming tasks, were detected. Such aptitudes are represented in three groups of students: those who learn easily, those who never seem to fully grasp what programming requires despite true effort, and those who experience a sudden insight, making them leap from a point were they had difficulties to another where they overcome them. By interviewing teachers and students, abstraction and sequencing elaboration were found to be the two core skills for programming. These results impelled us to consider the mental models’ approach, concluding that there are very specific cognitive functions that are more favorable to learn programming and that are fostered by more adequate schemas of representing reality. Some conclusions involving Problem-based learning as a fit teaching methodology to overcome students’ difficulties are also presented

Factors shaping young tourists' intentions to travel to Greece, Israel and Portugal: Universal or idisyncratic perceptions of young Greeks, Israelis and Portugese?

Tourism constitutes an important branch of economy, especially in countries experiencing economic crisis and harsh socio-political events. The current study compares the intention of young people from three different countries – Greece, Israel and Portugal - to travel to two selected destinations. For each country of origin the other two countries were the destination of interest. This research examined the factors affecting young tourists' intention to travel to different destinations assuming that those determinants depend on the country of origin as well as on the destination country. The sample comprised of 648 students: Israelis (277), Portuguese (200), Greeks (171). The research questionnaire was distributed in Israeli, Greek and Portuguese academic institutions in 2014. The results indicate that over half of the Israelis intend to visit Greece or Portugal. The majority of the Portuguese anticipate visiting Greece, while only 32.5% expect to visit Israel. Among the Greeks nearly 50% intend to visit Portugal and do not intend to visit Israel. The study showed that the main factors affecting the decisions of young Portuguese to travel to Israel were: the image of Israel, the perceived risk of traveling to a country with political unrest and the number of trips abroad. The main factors affecting the decisions of young Greeks were the perceived risk of traveling to a country with political unrest and Israel's image. Israelis' decision to travel to Greece was affected by their image of Greece; the Portuguese also took into account the perceived risk regarding economic situation. For Israelis, considering Portugal as a traveling destination was related to the destination's image. The Greeks were affected by the number of Facebook friends and the Innovation, Entrepreneurship and Digital Ecosystems perceived economic risk. This research suggests that the socio-economic, political context of the country of origin and of the tourist destination plays an important role in young tourists' travelling-related decision-making.info:eu-repo/semantics/publishedVersio

Influence of the contact–impact force model on the dynamic response of multi-body systems

This work deals with contact–impact force models for both spherical and cylindrical contact surfaces. The incorporation of the friction phenomenon, based on the Coulomb friction law, is also discussed together with an effective computational strategy, which includes the automatic step size selection procedure. Impacts within a revolute clearance joint in a basic slider–crank mechanism are used as an example to compare the different contact force models. The collision is a prominent phenomenon in manymulti-body systems such as mechanisms with intermittent motion, kinematic discontinuities, and clearance joints. As a result of an impact, the values of the system state variables change very fast, eventually looking like discontinuities in the system velocities and accelerations. The impact is characterized by large forces that are applied and removed in a short time period. The knowledge of the peak forces developed in the impact process is very important for the dynamic analysis of multibody systems and it has consequences in the design process. The model for the contact–impact force must consider the material and geometric properties of the colliding surfaces, consider information on the impact velocity, contribute to an efficient integration, and account for some level of energy dissipation. These characteristics are ensured with a continuous contact force model, in which the deformation and contact forces are considered as continuous functions.FEDER - Project POCTI/2001/EME/38281.Fundação para a Ciência e a Tecnologia (FCT)

Corneal Biomechanics in Ectatic Diseases: Refractive Surgery Implications.

BACKGROUND: Ectasia development occurs due to a chronic corneal biomechanical decompensation or weakness, resulting in stromal thinning and corneal protrusion. This leads to corneal steepening, increase in astigmatism, and irregularity. In corneal refractive surgery, the detection of mild forms of ectasia pre-operatively is essential to avoid post-operative progressive ectasia, which also depends on the impact of the procedure on the cornea. METHOD: The advent of 3D tomography is proven as a significant advancement to further characterize corneal shape beyond front surface topography, which is still relevant. While screening tests for ectasia had been limited to corneal shape (geometry) assessment, clinical biomechanical assessment has been possible since the introduction of the Ocular Response Analyzer (Reichert Ophthalmic Instruments, Buffalo, USA) in 2005 and the Corvis ST (Oculus Optikgerate GmbH, Wetzlar, Germany) in 2010. Direct clinical biomechanical evaluation is recognized as paramount, especially in detection of mild ectatic cases and characterization of the susceptibility for ectasia progression for any cornea. CONCLUSIONS: The purpose of this review is to describe the current state of clinical evaluation of corneal biomechanics, focusing on the most recent advances of commercially available instruments and also on future developments, such as Brillouin microscopy.(undefined)info:eu-repo/semantics/publishedVersio

Conservative Management of Asymptomatic Adnexal Masses Classified as Benign by the IOTA ADNEX Model: a Prospective Multicenter Portuguese Study

This prospective multicentric study aiming to determine the incidence of complications (malignant transformation, torsion or rupture) during conservative management of adnexal masses was performed in two Portuguese tertiary referral hospitals. It included ≥18-year-old, non-pregnant patients with asymptomatic adnexal masses (associated IOTA ADNEX risk of malignancy < 10%) sonographically diagnosed between January 2016 and December 2020. Conservative patient management consisted of serial clinical and ultrasound assessment up to 60 months of follow-up, spontaneous resolution of the formation or surgical excision (median follow-up: 17.8; range 9-48 months). From the 573 masses monitored (328 premenopausal and 245 postmenopausal adnexal masses), no complications were observed in 99.5%. The annual lesion growth rates and increases in morphological complexity were similar in the premenopausal and postmenopausal patients. Spontaneous resolution, evidenced in 16.4% of the patients, was more common in the premenopausal group (p < 0.05). Surgical intervention was performed in 18.4% of the cases; one borderline and one invasive FIGO IA stage cancer were diagnosed. There was an isolated case of ovary torsion (0.17%). These data support conservative management as a safe option for sonographically benign, stable and asymptomatic adnexal masses before and after menopause and highlight the need for expedite treatment of symptomatic or increased-morphological-complexity lesions.info:eu-repo/semantics/publishedVersio

Modelling Deformations in Car Crash animation

In this paper, we present a prototype of a deformation engine to efficiently model and render the damaged structure of vehicles in crash scenarios. We introduce a novel system architecture to accelerate the computation, which is traditionally an extremely expensive task. We alter a rigid body simulator to predict trajectories of cars during a collision and formulate a correction procedure to estimate the deformations of the collapsed car structures within the contact area. Non-linear deformations are solved based on the principle of energy conservation. Large plastic deformations resulting from collisions are modelled as a weighted combination of deformation examples of beams which can be produced using classical mechanics

Thermal and photochemical reactions of n-pyridinebenzopyrylium multistate of species (n = 2′,3′,4′). Exploring the synthetic potentialities from the unique reactivity of position 2′

Funding Information: This work was supported by the Associate Laboratory for Green Chemistry – LAQV (projects UIDB/50006/2020 and UIDP/ 50006/2020), the Research Unit on Applied Molecular Biosciences – UCIBIO (projects UIDP/04378/2020 and UIDB/ 04378/2020) and the Associate Laboratory Institute for Health and Bioeconomy – i4HB (project LA/P/0140/2020) which are financed by national funds from FCT/MCTES. FCT/MCTES is also acknowledged for supporting the National Portuguese NMR Network (ROTEIRO/0031/2013–PINFRA/22161/2016, cofinanced by FEDER through COMPETE 2020, POCI, PORL, and FCT through PIDDAC). A. C. acknowledges financing from Fundação Calouste Gulbenkian, grant no. 219201, and from the Angolan Embassy in Lisbon, Portugal, INAGBE grant. Dr. Ramesh Pandian is acknowledged for the initial acquisition and processing of single crystal X-ray data. Publisher Copyright: © 2023 The Author(s)The kinetics and thermodynamics of the pH-dependent multistate of species generated by the trans-chalcone of n-pyridinebenzopyrylium (n = 2′, 3′) were studied by UV–vis spectroscopy, 1H NMR and HPLC-MS, and the results compared with those reported for n = 4′. Due to the slow kinetics of the multistate species interconversion, the conjugation of these techniques has shown to be a powerful tool to investigate the behaviour of these systems. The species involved in the multistate are mutatis mutandis the same observed in anthocyanins and related compounds except for the flavylium cation, which was not observed in these systems even in very acidic medium. The rates of the interconversion of the multistate species upon pH stimuli are much slower than in anthocyanins. The compound bearing the pyridine nitrogen in position 2′ gives two novel products absorbing in the visible. Formation of the new products is particularly efficient from the thermal evolution of the photochemical products obtained upon light irradiation of the protonated trans-chalcone in a mixture of methanol:acidic water (1:1). This confirms the unique capacity of the substituents in position 2′ in giving intramolecular reactions involving the benzopyrylium core. Crystal structures for the three pyridine chalcone compounds (n = 2′, 3′, 4′) were obtained and the respective structures discussed.publishersversionpublishe