967 resultados para Lucardesi, Giovanni Paolo.


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As the ESA Rosetta mission approached, orbited, and sent a lander to comet 67P/Churyumov-Gerasimenko in 2014, a large campaign of ground-based observations also followed the comet. We constrain the total activity level of the comet by photometry and spectroscopy to place Rosetta results in context and to understand the large-scale structure of the comet's coma pre-perihelion. We performed observations using a number of telescopes, but concentrate on results from the 8m VLT and Gemini South telescopes in Chile. We use R-band imaging to measure the dust coma contribution to the comet's brightness and UV-visible spectroscopy to search for gas emissions, primarily using VLT/FORS. In addition we imaged the comet in near-infrared wavelengths (JHK) in late 2014 with Gemini-S/Flamingos 2. We find that the comet was already active in early 2014 at heliocentric distances beyond 4 au. The evolution of the total activity (measured by dust) followed previous predictions. No gas emissions were detected despite sensitive searches. The comet maintains a similar level of activity from orbit to orbit, and is in that sense predictable, meaning that Rosetta results correspond to typical behaviour for this comet. The gas production (for CN at least) is highly asymmetric with respect to perihelion, as our upper limits are below the measured production rates for similar distances post-perihelion in previous orbits.

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This study introduces an inexact, but ultra-low power, computing architecture devoted to the embedded analysis of bio-signals. The platform operates at extremely low voltage supply levels to minimise energy consumption. In this scenario, the reliability of static RAM (SRAM) memories cannot be guaranteed when using conventional 6-transistor implementations. While error correction codes and dedicated SRAM implementations can ensure correct operations in this near-threshold regime, they incur in significant area and energy overheads, and should therefore be employed judiciously. Herein, the authors propose a novel scheme to design inexact computing architectures that selectively protects memory regions based on their significance, i.e. their impact on the end-to-end quality of service, as dictated by the bio-signal application characteristics. The authors illustrate their scheme on an industrial benchmark application performing the power spectrum analysis of electrocardiograms. Experimental evidence showcases that a significance-based memory protection approach leads to a small degradation in the output quality with respect to an exact implementation, while resulting in substantial energy gains, both in the memory and the processing subsystem.

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Wearable devices performing advanced bio-signal analysis algorithms are aimed to foster a revolution in healthcare provision of chronic cardiac diseases. In this context, energy efficiency is of paramount importance, as long-term monitoring must be ensured while relying on a tiny power source. Operating at a scaled supply voltage, just above the threshold voltage, effectively helps in saving substantial energy, but it makes circuits, and especially memories, more prone to errors, threatening the correct execution of algorithms. The use of error detection and correction codes may help to protect the entire memory content, however it incurs in large area and energy overheads which may not be compatible with the tight energy budgets of wearable systems. To cope with this challenge, in this paper we propose to limit the overhead of traditional schemes by selectively detecting and correcting errors only in data highly impacting the end-to-end quality of service of ultra-low power wearable electrocardiogram (ECG) devices. This partition adopts the protection of either significant words or significant bits of each data element, according to the application characteristics (statistical properties of the data in the application buffers), and its impact in determining the output. The proposed heterogeneous error protection scheme in real ECG signals allows substantial energy savings (11% in wearable devices) compared to state-of-the-art approaches, like ECC, in which the whole memory is protected against errors. At the same time, it also results in negligible output quality degradation in the evaluated power spectrum analysis application of ECG signals.

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Reinforced concrete (RC) jacketing is a common method for retrofitting existing columns with poor structural performance. It can be applied in two different ways: if the continuity of the jacket is ensured, the axial load of the column can be transferred to the jacket, which will be directly loaded; conversely, if no continuity is provided, the jacket will induce only confinement action. In both cases the strength and ductility evaluation is rather complex, due to the different physical phenomena included, such as confinement, core-jacket composite action, preload and buckling of longitudinal bars.
Although different theoretical studies have been carried out to calculate the confinement effects, a practical approach to evaluate the flexural capacity and ductility is still missing. The calculation of these quantities is often related to the use of commercial software, taking advantage of numerical methods such as fibre method or finite element method.
This paper presents a simplified approach to calculate the flexural strength and ductility of square RC jacketed sections subjected to axial load and bending moment. In particular the proposed approach is based on the calibration of the stress-block parameters including the confinement effect. Equilibrium equations are determined and buckling of longitudinal bars is modelled with a suitable stress-strain law. Moment-curvature curves are derived with simple calculations. Finally, comparisons are made with numerical analyses carried out with the code OpenSees and with experimental data available in the literature, showing good agreement.

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Ancient columns, made with a variety of materials such as marble, granite, stone or masonry are an important part of the
European cultural heritage. In particular columns of ancient temples in Greece and Sicily which support only the architrave are
characterized by small axial load values. This feature together with the slenderness typical of these structural members clearly
highlights as the evaluation of the rocking behaviour is a key aspect of their safety assessment and maintenance. It has to be noted
that the rocking response of rectangular cross-sectional columns modelled as monolithic rigid elements, has been widely investigated
since the first theoretical study carried out by Housner (1963). However, the assumption of monolithic member, although being
widely used and accepted for practical engineering applications, is not valid for more complex systems such as multi-block columns
made of stacked stone blocks, with or without mortar beds. In these cases, in fact, a correct analysis of the system should consider
rocking and sliding phenomena between the individual blocks of the structure. Due to the high non-linearity of the problem, the
evaluation of the dynamic behaviour of multi-block columns has been mostly studied in the literature using a numerical approach
such as the Discrete Element Method (DEM). This paper presents an introductory study about a proposed analytical-numerical
approach for analysing the rocking behaviour of multi-block columns subjected to a sine-pulse type ground motion. Based on the
approach proposed by Spanos (2001) for a system made of two rigid blocks, the Eulero-Lagrange method to obtain the motion
equations of the system is discussed and numerical applications are performed with case studies reported in the literature and with a
real acceleration record. The rocking response of single block and multi-block columns is compared and considerations are made
about the overturning conditions and on the effect of forcing function’s frequency.
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BACKGROUND: Smoking is the most important individual risk factor for many cancer sites but its association with breast and prostate cancer is not entirely clear. Rate advancement periods (RAPs) may enhance communication of smoking related risk to the general population. Thus, we estimated RAPs for the association of smoking exposure (smoking status, time since smoking cessation, smoking intensity, and duration) with total and site-specific (lung, breast, colorectal, prostate, gastric, head and neck, and pancreatic) cancer incidence and mortality.

METHODS: This is a meta-analysis of 19 population-based prospective cohort studies with individual participant data for 897,021 European and American adults. For each cohort we calculated hazard ratios (HRs) for the association of smoking exposure with cancer outcomes using Cox regression adjusted for a common set of the most important potential confounding variables. RAPs (in years) were calculated as the ratio of the logarithms of the HRs for a given smoking exposure variable and age. Meta-analyses were employed to summarize cohort-specific HRs and RAPs.

RESULTS: Overall, 140,205 subjects had a first incident cancer, and 53,164 died from cancer, during an average follow-up of 12 years. Current smoking advanced the overall risk of developing and dying from cancer by eight and ten years, respectively, compared with never smokers. The greatest advancements in cancer risk and mortality were seen for lung cancer and the least for breast cancer. Smoking cessation was statistically significantly associated with delays in the risk of cancer development and mortality compared with continued smoking.

CONCLUSIONS: This investigation shows that smoking, even among older adults, considerably advances, and cessation delays, the risk of developing and dying from cancer. These findings may be helpful in more effectively communicating the harmful effects of smoking and the beneficial effect of smoking cessation.

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BACKGROUND: Disability-adjusted life-years (DALYs) are an indicator of mortality, morbidity, and disability. We calculated DALYs for cancer in middle-aged and older adults participating in the Consortium on Health and Ageing Network of Cohorts in Europe and the United States (CHANCES) consortium.

METHODS: A total of 90 199 participants from five European cohorts with 10 455 incident cancers and 4399 deaths were included in this study. DALYs were calculated as the sum of the years of life lost because of premature mortality (YLLs) and the years lost because of disability (YLDs). Population-attributable fractions (PAFs) were also estimated for five cancer risk factors, ie, smoking, adiposity, physical inactivity, alcohol intake, and type II diabetes.

RESULTS: After a median follow-up of 12 years, the total number of DALYs lost from cancer was 34 474 (382 per 1000 individuals) with a similar distribution by sex. Lung cancer was responsible for the largest number of lost DALYs (22.9%), followed by colorectal (15.3%), prostate (10.2%), and breast cancer (8.7%). Mortality (81.6% of DALYs) predominated over disability. Ever cigarette smoking was the risk factor responsible for the greatest total cancer burden (24.0%, 95% confidence interval [CI] = 22.2% to 26.0%), followed by physical inactivity (4.9%, 95% CI = 0.8% to 8.1%) and adiposity (1.8%, 95% CI = 0.2% to 2.8%).

CONCLUSIONS: DALYs lost from cancer were substantial in this large European sample of middle-aged and older adults. Even if the burden of disease because of cancer is predominantly caused by mortality, some cancers have sizeable consequences for disability. Smoking remained the predominant risk factor for total cancer burden.

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Este estudo parte da hipótese de que os serviços militares, a linhagem e a cultura católica se mantiveram como os referentes centrais do ethos nobiliario em Portugal e em Espanha no século XVII, com pouca diferenças relativamente ao conjunto de valores elaborado pelo próprio grupo desde a época medieval. O estudo de caso incide sobre a família dos Albuquerque Coelho desde o século XVI até finais do XVII, acompanhando o seu multifacetado processo de ascensão social, onde pontuam a sua implantação no Brasil (Pernambuco) e as opções políticas por eles tomadas na sequência do 1º de Dezembro de 1640

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Although security plays an important role in the development of multiagent systems, a careful analysis of software development processes shows that the definition of security requirements is, usually, considered after the design of the system. One of the reasons is the fact that agent oriented software engineering methodologies have not integrated security concerns throughout their developing stages. The integration of security concerns during the whole range of the development stages can help towards the development of more secure multiagent systems. In this paper we introduce extensions to the Tropos methodology to enable it to model security concerns throughout the whole development process. A description of the new concepts and modelling activities is given along with a discussion on how these concepts and modelling activities are integrated to the current stages of Tropos. A real life case study from the health and social care sector is used to illustrate the approach.

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A computer system's security can be compromised in many ways—a denial-of-service attack can make a server inoperable, a worm can destroy a user's private data, or an eavesdropper can reap financial rewards by inserting himself in the communication link between a customer and her bank through a man-in-the-middle (MITM) attack. What all these scenarios have in common is that the adversary is an untrusted entity that attacks a system from the outside—we assume that the computers under attack are operated by benign and trusted users. But if we remove this assumption, if we allow anyone operating a computer system—from system administrators down to ordinary users—to compromise that system's security, we find ourselves in a scenario that has received comparatively little attention.

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Biodiversity continues to decline in the face of increasing anthropogenic pressures such as habitat destruction, exploitation, pollution and introduction of alien species. Existing global databases of species’ threat status or population time series are dominated by charismatic species. The collation of datasets with broad taxonomic and biogeographic extents, and that support computation of a range of biodiversity indicators, is necessary to enable better understanding of historical declines and to project – and avert – future declines. We describe and assess a new database of more than 1.6 million samples from 78 countries representing over 28,000 species, collated from existing spatial comparisons of local-scale biodiversity exposed to different intensities and types of anthropogenic pressures, from terrestrial sites around the world. The database contains measurements taken in 208 (of 814) ecoregions, 13 (of 14) biomes, 25 (of 35) biodiversity hotspots and 16 (of 17) megadiverse countries. The database contains more than 1% of the total number of all species described, and more than 1% of the described species within many taxonomic groups – including flowering plants, gymnosperms, birds, mammals, reptiles, amphibians, beetles, lepidopterans and hymenopterans. The dataset, which is still being added to, is therefore already considerably larger and more representative than those used by previous quantitative models of biodiversity trends and responses. The database is being assembled as part of the PREDICTS project (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems – www.predicts.org.uk). We make site-level summary data available alongside this article. The full database will be publicly available in 2015.

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Riassunto: Dedicato «alle scuole e agli amatori della lingua», ai lettori interessati e preoccupati delle sorti della lingua nazionale, il periodico semestrale La Crusca per voi esce per la prima volta nell’ottobre 1990 con una Giustificazione e Un po’ di storia, in cui il fondatore Giovanni Nencioni spiega le ragioni dell’istituzione di un vero e proprio «consultorio linguistico», destinato ad accogliere le richieste, i dubbi, le perplessità sul corretto impiego della lingua italiana proveniente da persone di ogni livello sociale e culturale. Scopo di questo lavoro è studiare la tipologia dei quesiti posti agli accademici della Crusca, con particolare attenzione a fenomeni di carattere lessicale, negli ultimi diciotto numeri del periodico (dal 2005 al 2013, con qualche prelievo da uscite precedenti). Conclude il lavoro una breve indagine a campione sulla diffusione e la traducibilità di alcuni termini stranieri in italiano.

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The number of comparative studies in the field of political communication increased considerably after Daniel Hallin and Paolo Mancini's publication of comparing Media systems. In this book, four dimensions are used to distinguish between the media environments in western countries around the year 2000: press market development, parallelism between parties and media outlets, state intervention in the realm of media, and levels of journalist professionalization. The authors conclude that in western Europe and North America three types of media systems coexisted: a polarized pluralist model (in southern Europe), a democratic corporatist model (in scandinavia and some western European countries), and a liberal model (Canada, USA, Ireland, and the UK). Within this framework, both Portugal and Spain are described as polarized pluralist media systems, given their weak press markets and low patterns of journalistic professionalization, as well as strong state intervention in the realm of media and parallelism between media outlets and political parties.

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In this presentation I discuss two recent works that use new technologies to explore the expression or communication of individual human identity.

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Soil vapor extraction (SVE) is an efficient, well-known and widely applied soil remediation technology. However, under certain conditions it cannot achieve the defined cleanup goals, requiring further treatment, for example, through bioremediation (BR). The sequential application of these technologies is presented as a valid option but is not yet entirely studied. This work presents the study of the remediation of ethylbenzene (EB)-contaminated soils, with different soil water and natural organic matter (NOMC) contents, using sequential SVE and BR. The obtained results allow the conclusion that: (1) SVE was sufficient to reach the cleanup goals in 63% of the experiments (all the soils with NOMC below 4%), (2) higher NOMCs led to longer SVE remediation times, (3) BR showed to be a possible and cost-effective option when EB concentrations were lower than 335 mg kgsoil −1, and (4) concentrations of EB above 438 mg kgsoil −1 showed to be inhibitory for microbial activity.