331 research outputs found

    Individualism vs. collectivism in a sharing economy context: A study on what determines Portuguese consumers’ participation

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    Consumers rely on warmth and competence, two fundamental dimensions that drive social judgments of people, to form perceptions of companies and, ultimately, make their market consumption decisions. In a Sharing Economy (SE) context, however, are there more profound and hidden motives for consumer behavior, namely the orientation–individualistic/idiocentric or collectivist/allocentric (Triandis & Gelfand, 1998) –of individuals of a given culture, for example? Meaning: does an individualistic/idiocentric orientation (in a “selfish” and “opportunistic” perspective without any kind of collectivist concerns that they are participating in something that is for the good of society and community as a whole) and/or a collectivist/allocentric orientation (in an “altruist” perspective, towards a collectivist/communal orientation) play a central role in determining consumers’ willingness to participate in sharing-based programs (SBP) of the SE? Furthermore, what drives such relationship? Meaning: what mediates such two variables (independent variable: individualism/collectivism; and dependent variable: willingness to participate)? In searching for an answer, this research conducted two studies: 1) Correlation –with the aim to find out whether these two variables are associated or related in some way, in other words, whether Individualism and/or Collectivism have a positive, a negative or no effect whatsoever on the willingness to participate in SBP of the SE; 2) Mediation analysis –with the aim to find out what explains (what mediates) the relationship between the two variables. Having Portuguese consumers as our targeted population, our tentative findings are expected to reveal that (i) individualism is the dominant dimension that plays a determinant role in influencing Portuguese consumer’s participation in the SE and (ii) such relationship is driven by the transformation expectations that such participation may in stil in their lives –at the level of emotions and experiential benefits. We present an innovative research, as, to the best of our knowledge, it is the first in investigating the relationship between individualistic/idiocentric or/and collectivist/allocentric orientation and consumers’ participation in SBP of the SE.info:eu-repo/semantics/acceptedVersio

    Efficacy of beta-blocker therapy in symptomatic athletes with exercise-induced intra-ventricular gradients

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    <p>Abstract</p> <p>Background</p> <p>Upright exercise stress echocardiography (SE) induces significant intraventricular gradient (IVG) and systolic anterior motion (SAM) in a large proportion of symptomatic athletes, who may therefore benefit from a negative inotropic therapy.</p> <p>The purpose of the present study was to assess the effect of chronic oral β blocker therapy on the occurrence of exercise-induced IVG and mitral valve SAM, in symptomatic athletes.</p> <p>Methods</p> <p>We enrolled 35 symptomatic athletes (age = 23 ± 11 years) with IVG (>30 mmHg) during SE off therapy. All repeated SE on chronic oral beta-blocker therapy (atenolol up to 50 mg, bisoprolol up to 10 mg, or metoprolol up to 100 mg daily according to physician-driven choice).</p> <p>Results</p> <p>On therapy, there was during SE a reduction in IVG (35 off vs 17 on beta blocker, p < 0.01), decrease of IVG (102 ± 34 mmHg off vs 69 ± 24 mmHg on beta blocker, p < 0.01), peak heart rate (178 ± 15 bpm off vs 157 ± 9 bpm on beta blocker), SAM (24 off vs 9 on beta blocker, p < 0.001), symptoms during SE (17 off vs 2 on beta blocker p < 0.001), ST segment depression (13 off vs 2 on beta blocker, p < 0.001).</p> <p>Conclusions</p> <p>In athletes with positive screening on medical evaluation for sports practice and IVG on exertion, treatment with oral beta blockers improved symptoms in the large majority of patients. Symptomatic benefit was mirrored by objective evidence of improvement of echocardiographic signs of obstruction (IVG and SAM) and reduction of ischemia-like electrocardiographic changes.</p

    Making sense of the sharing economy: a category formation approach

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    The sharing economy (SE) has drawn significant attention from several society stakeholders in the last five years. While business actors are interested in financial opportunities to meet consumer needs, new business models, academia and governmental organisations are concerned with potential unintended effects on society and the environment. Despite its notable global growth, there is still a lack of more solid ground in understanding its origins and respective mechanisms through which it has been evolving as a category. This research addresses the problematics of the origins and ascendency of the SE by examining the process by which it is arising as a new category, searching for conceptual clarification, and pinpointing the legitimacy granted by stakeholders. Our guiding research questions are: how the SE was formed and evolved as a category, and as a category, is the SE legitimate? Additionally, we attempt to identify the nature of the SE as a category. Making a historical analysis of the expression SE and its equivalents, this paper deepens the discussion about the SE’s nature by providing evidence that it has predominantly been formed by emergence processes, comprising social movement, similarity clustering, and truce components, which render the SE a particular case of category formation and allow communication, entrepreneurship, regulation, and research about what it is. Moreover, the findings reveal a generalised legitimacy granted to the SE by a vast number of stakeholders, although still lacking the consolidation of socio-political legitimation. The SE’s nature seems to fall into a metaphorical approach, notably, the notion of radial categories.info:eu-repo/semantics/publishedVersio

    Clinical significance of intraventricular gradient during effort in an adolescent karate player

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    The authors report the case of a 16-year-old boy who practices karate, who underwent medical evaluation because of atypical chest discomfort, related to strenuous effort. The ECG and echocardiogram findings were normal. The young boy did a treadmill stress test which was positive for myocardial ischemia. Late during the investigation, he underwent treadmill stress echocardiography, during which he developed intraventricular gradient of over 130 mmHg with end-systolic peak and systolic anterior movement (SAM) of the mitral valve. These echocardiographic findings were not present at rest and disappeared shortly after termination of exercise. The authors discuss the significance of this event. This leads us to advise withdrawal from participation in competitive sport according to the recomendations of the European Society of Cardiology. A possible role of exercise stress echo for intraventricular pressure gradient assessment in symptomatic athletes with structurally normal hearts is suggested

    Exercise-induced intra-ventricular gradients as a frequent potential cause of myocardial ischemia in cardiac syndrome X patients

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    <p>Abstract</p> <p>Background</p> <p>The development of intra-ventricular gradients (IVG) during dobutamine or exercise stress is not infrequent, and can be associated to symptoms during stress.</p> <p>The purpose of this study was to assess the occurrence of IVG during exercise stress echocardiography in cardiac syndrome X patients.</p> <p>Methods</p> <p>We prospectively evaluated 91 patients (pts) mean aged 51 ± 12 years (age ranged 20 to 75 years old), 44 of whom were women. All pts had angina, positive exercise ECG treadmill testing, normal rest echocardiogram and no coronary artery disease on coronary angiogram (cardiac X syndrome). After complete Doppler echocardiographic evaluation with determination of left ventricular outflow tract index (LVOTi), relative left ventricular wall thickness (RLVWT) and left ventricular end-diastolic volume index (LVDVi), all patients underwent stress echocardiography with two-dimensional and Doppler echographic evaluation during and after treadmill exercise.</p> <p>Results</p> <p>For analysis purpose patients were divided in 2 groups, according to the development of IVG. Doppler evidence of IVG was found in 33 (36%) of the patients (Group A), with mean age 47 ± 14 years old (age ranged 20 to 72 years) and with a mean end-systolic peak gradient of 86 ± 34 mmHg (ranging from 30 to 165 mmHg). The IVG development was accompanied by SAM of the mitral valve in 23 pts. Three of these pts experienced symptomatic hypotension. Ten were women (30% pts). 58 pts in group B, 34 of whom were women (59%) (p = 0,01 vs group A), mean aged 53,5 ± 10,9 years old (age ranged 34 to 75 years) (p = 0,03 vs group A), did not develop IVG. LVOTi was 10,29 ± 0,9 mm/m<sup>2 </sup>in group A and 11,4 ± 1 mm/m<sup>2 </sup>in group B (p < 0,000); RLVWT was 0,36 ± 0,068 in group A and 0,33 ± 0,046 in group B (p < 0,01); LVDVi was 44,8 ± 10 ml/m<sup>2 </sup>in group A and 56 ± 11,6 ml/m<sup>2 </sup>in group B (p = 0,000).</p> <p>Conclusion</p> <p>1. A significant number of patients with cardiac X syndrome developed IVG during upright exercise in treadmill. These pts (group A) are mainly males and younger than those who did not develop IVG.</p> <p>2. The development of IVG and mitral valve SAM on exertion seems to be associated with ST segment downsloping during stress testing in patients without epicardial coronary disease.</p> <p>3. The development of IVG and mitral valve SAM seems to be associated with lower LVOTi, lower LVDVi and higher RLVWT.</p

    Prevalência de anticorpos contra o vírus da hepatite B em população urbana do nordeste brasileiro

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    A sample of 1,288 inhabitants of Salvador, Bahia, Brazil, were submitted to the determination of anti-HBs using radioimmunoassay procedure, and analysed according to age, sex and income. Overall prevalence of anti-HBs was 11,8%. ranging from 6,7% among children aged less than three years old to 26,1% among those aged 30 years and older. Males presented prevalence of anti-HBs similar to female individuals, and those with a higher income showed frequencies of anti-HBs greater than those with a lower income level. The following conclusions were drawn: The high prevalence of anti-HBs observed among children suggests early contact with hepatitis B virus, possibly due to vertical transmission and intrafamiliar dissemination of the disease; the frequency of anti-HBs increases with age; the lower prevalence of anti-HBs among those with low income suggests that this group may present higher prevalence of carriers of the hepatitis B virus surface antigen.Um grupo de 1.288 indivíduos, residentes em Salvador, Bahia, Brasil, foi examinado para a determinação de anti-HBs, utilizando-se a técnica do radioimunoensaio. Os resultados foram analisados de acordo com a idade, o sexo e o nível de renda. Uma prevalência de anti-HBs de 11,8% foi observada, variando de 6,7% nas crianças com idade inferior a três anos, a 26,1% para aqueles com idade superior a 30 anos. A prevalência de anti-HBs foi similar em indivíduos do sexo masculino e feminino. Aqueles com nível de renda mais alto tiberam prevalência de anti-HBs maior que o grupo de renda baixa. Dos resultados conclui-se: a alta prevalência de anti-HBs em crianças sugere o contato precoce com o vírus da hepatite B, possivelmente relacionado com a transmissão vertical e a disseminação intraíamiliar do vírus; a freqüência de anti-HBs aumentou com a idade; a baixa prevalência de anti-HBs entre aqueles com baixo nível sócio-econômico sugere que neste grupo pode ser alta a prevalência de portadores do vírus B da hepatite

    Power Saving MAC Protocols in Wireless Sensor Networks: A Performance Assessment Analysis

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    Wireless sensor networks are an emerging technology that is used to monitor points or objects of interest in an area. Despite its many applications, this kind of network is often limited by the fact that it is difficult to provide energy to the nodes continuously, forcing the use of batteries, which restricts its operations. Network density may also lead to other problems. Sparse networks require stronger transmissions and have little redundancy while dense networks increase the chances of overhearing and interference. To address these problems, many novel medium access control (MAC) protocols have been developed through the years. The objective of this study is to assess the effectiveness of the T-MAC, B-MAC, and RI-MAC protocols in a variable density network used to collect data inside freight trucks carrying fruits that perish quickly. This article is part of the PrunusPós project, which aims to increase the efficiency of peach and cherry farming in Portugal. The comparison was done using the OMNET++ simulation framework. Our analysis covers the behavior and energetic properties of these protocols as the density of the network increases and shows that RI-MAC is more adaptable and consumes less energy than the alternatives.This study is within the activities of project “PrunusPós - Optimization of processes for the storage, cold conservation, active and/or intelligent packaging and food quality traceability in post-harvested fruit products”, project n. º PDR2020-101-031695, Partnership n.º 87, initiative n.º 175, promoted by PDR 2020 and co-funded by FEADER within Portugal 2020. P.D.G. thanks the support of Fundação para a Ciência e Tecnologia (FCT) and C-MAST - Centre for Mechanical and Aerospace Science and Technologies, under project UIDB/00151/2020. V. N. G. J. S. and J. M. L. P. C. acknowledge that this work is funded by FCT/MCTES through national funds and when applicable co-funded EU funds under the project UIDB/50008/2020. The authors would also like to acknowledge the company InspiringSci, Lda for its interest and valuable contribution to the successful development of this work.info:eu-repo/semantics/publishedVersio

    Power saving MAC protocols in wireless sensor networks: a survey

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    In a wireless sensor network, energy is almost always the greatest limitation. Energy sources are restricted in many of the environments where nodes are deployed, limiting them to the use of batteries for power. Therefore, conserving energy is supremely important, however, such a task poses many challenges to hardware and protocol design. One of the greatest problems faced is reducing the energy consumption of the communications systems, which represents a substantial amount of the total consumption. This paper surveys the most recent schemes designed to reduce the communications module energy consumption with a focus on novel MAC protocols for ad-hoc wireless sensor networks. It initially describes the many challenges involved, then it analyses each protocol individually. Finally, the presented protocols are compared and the issues that remain open are raised for further research

    Exposição Acidental a Picada de Agulha. Protocolo de Actuação

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    A picada acidental por agulha em crianças e adolescentes provoca grande ansiedade aos pais e é causa de recurso aos serviços de urgência.A exposição acidental inclui a picada por agulha de seringa encontrada na comunidade. O risco de transmissão do vírus da hepatite B (VHB), C (VHC), vírus da imunodeficiência humana (VIH) e outros agentes é habitualmente baixo, no entanto é da responsabilidade do clínico informar e minimizar a possibilidade de ocorrer doença.As recomendações atuais referentes à profilaxia em crianças são baseadas no risco de transmissão e seroconversão após exposição ocupacional em adultos. No entanto, e apesar da escassez de dados, a exposição acidental a picada de agulha na idade pediátrica merece uma avaliação particular.Com o objetivo de definir uma política comum a todos os hospitais e garantir acesso a cuidados mais adequados a todas as crianças, os autores apresentam um protocolo de profilaxia após exposição acidental a picada de agulha em idade pediátrica
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