Teaching entrepreneurship in HEI: an analysis at the portuguese Polythecnics

Trabalho apresentado na Conference on Enabling Teachers for Entrepreneurship Education (ENTENP2013), 7-8 junho de 2013, Guarda, Portuga

ORB5: a global electromagnetic gyrokinetic code using the PIC approach in toroidal geometry

This paper presents the current state of the global gyrokinetic code ORB5 as an update of the previous reference [Jolliet et al., Comp. Phys. Commun. 177 409 (2007)]. The ORB5 code solves the electromagnetic Vlasov-Maxwell system of equations using a PIC scheme and also includes collisions and strong flows. The code assumes multiple gyrokinetic ion species at all wavelengths for the polarization density and drift-kinetic electrons. Variants of the physical model can be selected for electrons such as assuming an adiabatic response or a ``hybrid'' model in which passing electrons are assumed adiabatic and trapped electrons are drift-kinetic. A Fourier filter as well as various control variates and noise reduction techniques enable simulations with good signal-to-noise ratios at a limited numerical cost. They are completed with different momentum and zonal flow-conserving heat sources allowing for temperature-gradient and flux-driven simulations. The code, which runs on both CPUs and GPUs, is well benchmarked against other similar codes and analytical predictions, and shows good scalability up to thousands of nodes

Quasi-steady and steady states in global gyrokinetic particle-in-cell simulations

Collisionless delta-f gyrokinetic particle-in-cell simulations suffer from the entropy paradox, in which the entropy grows linearly in time while low-order moments are saturated. As a consequence, these simulations do not reach a steady state and are unsuited to make quantitative predictions. A solution to this issue is the introduction of artificial dissipation. The notion of steady state in gyrokinetic simulations is studied by deriving an evolution equation for the fluctuation entropy and applying it to the global collisionless particle-in-cell code ORB5 [S. Jolliet , Comput. Phys. Commun. 177, 409 (2007)]. It is shown that a recently implemented noise-control algorithm [B. F. McMillan , Phys. Plasmas 15, 052308 (2008)] based on a W-stat provides the necessary dissipation to reach a steady state. The two interesting situations of decaying and driven turbulence are considered. In addition, it is shown that a separate heating algorithm, not based on a W-stat, does not lead to a statistical steady state

Rapid Fourier space solution of linear partial differential equations in toroidal magnetic confinement geometries

Fluctuating quantities in magnetic confinement geometries often inherit a strong anisotropy along the field lines. One technique for describing these structures is the use of a certain set of Fourier components on the tori of nested flux surfaces. We describe an implementation of this approach for solving partial differential equations, like Poisson's equation, where a different set of Fourier components may be chosen on each surface according to the changing safety factor profile. Allowing the resolved components to change to follow the anisotropy significantly reduces the total number of degrees of freedom in the description. This can permit large gains in computational performance. We describe, in particular, how this approach can be applied to rapidly solve the gyrokinetic Poisson equation in a particle code, ORB5 (Jolliet et al., (2007) [5]), with a regular (non-field-aligned) mesh. (C) 2009 Published by Elsevier B.V

Vamsa: Automated Provenance Tracking in Data Science Scripts

There has recently been a lot of ongoing research in the areas of fairness, bias and explainability of machine learning (ML) models due to the self-evident or regulatory requirements of various ML applications. We make the following observation: All of these approaches require a robust understanding of the relationship between ML models and the data used to train them. In this work, we introduce the ML provenance tracking problem: the fundamental idea is to automatically track which columns in a dataset have been used to derive the features/labels of an ML model. We discuss the challenges in capturing such information in the context of Python, the most common language used by data scientists. We then present Vamsa, a modular system that extracts provenance from Python scripts without requiring any changes to the users' code. Using 26K real data science scripts, we verify the effectiveness of Vamsa in terms of coverage, and performance. We also evaluate Vamsa's accuracy on a smaller subset of manually labeled data. Our analysis shows that Vamsa's precision and recall range from 90.4% to 99.1% and its latency is in the order of milliseconds for average size scripts. Drawing from our experience in deploying ML models in production, we also present an example in which Vamsa helps automatically identify models that are affected by data corruption issues

Environmental impact of omnivorous, ovo-lacto-vegetarian, and vegan diet

Food and beverage consumption has a great impact on the environment, although there is a lack of information concerning the whole diet. The environmental impact of 153 Italian adults (51 omnivores, 51 ovo-lacto-vegetarians, 51 vegans) and the inter-individual variability within dietary groups were assessed in a real-life context. Food intake was monitored with a 7-d dietary record to calculate nutritional values and environmental impacts (carbon, water, and ecological footprints). The Italian Mediterranean Index was used to evaluate the nutritional quality of each diet. The omnivorous choice generated worse carbon, water and ecological footprints than other diets. No differences were found for the environmental impacts of ovo-lacto-vegetarians and vegans, which also had diets more adherent to the Mediterranean pattern. A high inter-individual variability was observed through principal component analysis, showing that some vegetarians and vegans have higher environmental impacts than those of some omnivores. Thus, regardless of the environmental benefits of plant-based diets, there is a need for thinking in terms of individual dietary habits. To our knowledge, this is the first time environmental impacts of three dietary regimens are evaluated using individual recorded dietary intakes rather than hypothetical diet or diets averaged over a population

Salt content of prepacked cereal-based products and their potential contribution to salt intake of the Italian adult population: Results from a simulation study

Background and aims: High sodium intake is one of the main risk factors for noncommunicable diseases, and its consumption should be reduced. This study aimed to simulate changes in the daily salt intake of the Italian adult population based on consumption scenarios of prepacked cereal-based foods sold in Italy. Methods and results: Information on food packages was retrieved from 2893 cereal-based products. Potential changes in salt intake were simulated based on food consumption scenarios that consider the daily consumption of cereal-based products suggested in the Italian Dietary Guidelines and their current daily consumption by Italian adults. The highest salt content was retrieved in bread (median, 25th–75th percentile: 1.3, 1.1–1.4 g/100 g) and bread substitutes (1.8, 1.0–2.2 g/100 g). If the suggested daily amounts were consumed, bread would contribute to 44% of the 5 g salt/day target, whereas bread substitutes, breakfast cereals, biscuits and sweet snacks would marginally contribute (1–2%). Compared to bread with median salt content, a −44% and +10% salt intake would be observed if products within the first and the last quartile of salt content were chosen, respectively. However, considering the actual intake of Italian consumers, bread would cover 25% and bread substitutes 7% of the daily salt target. Conclusion: Food labels have a pivotal role and efforts are required to encourage consumers to use them to make healthy choices. Moreover, these results may contribute to setting sodium benchmarks in cereal-based products and encourage the food industry to reduce the salt content in the products

ACYLATED AND UNACYLATED GHRELIN IMPAIR SKELETAL MUSCLE ATROPHY IN MICE.

Cachexia is a wasting syndrome associated with cancer, AIDS, and multiple sclerosis, and several other disease states. It is characterized by weight loss, fatigue, loss of appetite and skeletal muscle atrophy and is associated with poor patient prognosis, making it an important treatment target. Ghrelin is a peptide hormone that stimulates growth hormone (GH) release and positive energy balance through binding to the receptor GHSR-1a. Only acylated ghrelin (AG), but not the unacylated form (UnAG), can bind GHSR-1a; however, UnAG and AG share several GHSR-1aindependent biological activities. Here we investigated whether UnAG and AG could protect against skeletal muscle atrophy in a GHSR-1a-independent manner. We found that both AG and UnAG inhibited dexamethasone-induced skeletal muscle atrophy and atrogene expression through PI3K\u3b2-, mTORC2-, and p38-mediated pathways in myotubes. Up-regulation of circulating UnAG in mice impaired skeletal muscle atrophy induced by either fasting or denervation without stimulating muscle hypertrophy and GHSR-1a-mediated activation of the GH/IGF-1 axis. In Ghsrdeficient mice, both AG and UnAG induced phosphorylation of Akt in skeletal muscle and impaired fasting-induced atrophy. These results demonstrate that AG and UnAG act on a common, unidentified receptor to block skeletal muscle atrophy in a GH-independent manner