The Lisbon Strategy

The Lisbon Strategy Targets are presented and assessed as accordingly to the domains of the structural indicators, the common indicators created to measure the progress towards reaching these objectives: Economic performance; Employment; Research, Innovation and education; Economic reform; Social cohesion; Environment.structural indicators, economic performance.

Bounding the mass of ultralight bosonic Dark Matter particles with the motion of the S2 star around Sgr A*

Dark matter is undoubtedly one of the fundamental, albeit unknown, components of the standard cosmological model. The failure to detect WIMPs, the most promising candidate particle for cold dark matter, actually opens the way for the exploration of viable alternatives, of which ultralight bosonic particles with masses $\sim 10^{-21}$ eV represent one of the most encouraging. Numerical simulations have shown that such particles form solitonic cores in the innermost parts of virialized galactic halos that are supported by internal quantum pressure on characteristic $\sim$kpc de Broglie scales. In the Galaxy, this halo region can be probed by means of S-stars orbiting the supermassive black hole Sagittarius A* to unveil the presence of such a solitonic core and, ultimately, to bound the boson mass $m_\psi$. Employing a Monte Carlo Markov Chain algorithm, we compare the predicted orbital motion of S2 with publicly available data and set an upper bound $m_\psi \lesssim 3.2\times 10^{-19}$ eV on the boson mass, at 95 \% confidence level. When combined with other galactic and cosmological probes, our constraints help to reduce the allowed range of the bosonic mass to $(2.0 \lesssim m_\psi \lesssim 32.2)\times 10^{-20}$ eV, at the 95 \% confidence level, which opens the way to precision measurements of the mass of the ultralight bosonic dark matter.Comment: 6 pages, 2 figures, 1 table. Accepted for publication on PRD. Additional plot and related code at http://produccioncientifica.usal.es/datos/6464bdb7a842f677be8feeb

Shutting the allowed mass range of the ultralight bosons with S2 star

It is well known that N-body simulations of ultralight bosons show the formation of a solitonic dark matter core in the innermost part of the halo. The scale length of such a soliton depends on the inverse of the mass of the boson. On the other hand, the orbital motion of stars in the Galactic Center depends on the distribution of matter whether be it baryonic or dark, providing an excellent probe for the gravitational field of the region. In this Letter we propose the S-stars in the Galactic Center as a new observational tool, complementary to other astrophysical systems, to narrow down the range of allowed values for an ultralight dark matter candidate boson mass. We built mock catalogs mirroring the forthcoming astrometric and spectroscopic observations of S2, and we used a MCMC analysis to predict the accuracy down to which the mass of an ultralight boson may be bounded, and we showed that, once complementary constraints are considered, this analysis will help to restrict the allowed range of the boson mass. Our analysis forecasts the bound on the mass of an ultralight boson to be $< 10^{-19}$ eV at the 95% of confidence level.Comment: 5 pages, 2 figures, 1 table, 5 appendices. Accepted for publication in A&A Letter

Novel highly conductive and transparent graphene based conductors

Future wearable electronics, displays and photovoltaic devices rely on highly conductive, transparent and yet mechanically flexible materials. Nowadays indium tin oxide (ITO) is the most wide spread transparent conductor in optoelectronic applications, however the mechanical rigidity of this material limits its use for future flexible devices. Here we report novel transparent conductors based on few layer graphene (FLG) intercalated with ferric chloride (FeCl3) with an outstandingly high electrical conductivity and optical transparency. We show that upon intercalation a record low sheet resistance of 8.8 Ohm/square is attained together with an optical transmittance higher than 84% in the visible range. These parameters outperform the best values of ITO and of other carbon-based materials, making these novel transparent conductors the best candidates for future flexible optoelectronics

Testing space-time geometries and theories of gravity at the Galactic Center with pulsar's time delay

We developed a numerical methodology to compute the fully-relativistic propagation time of photons emitted by a pulsar in orbit around a massive compact object, like the supermassive black hole Sagittarius A* in the Galactic Center, whose gravitational field is described by a generic spherically symmetric space-time. Pulsars at the Galactic Center are usually regarded as the next major precision probe for theories of gravity, filling the current experimental gap between horizon-scale gravity tests and those at larger scales. We retain a completely general approach, which allows us to apply our code to the Schwarzschild space-time (by which we successfully validate our methodology) and to three different well-motivated alternatives to the standard black hole paradigm. The results of our calculations highlight departures spanning several orders of magnitudes in timing residuals, that are supposed to be detectable with future observing facilities like the Square Kilometer Array.Comment: 15 pages, 8 figures, 1 table. Comments are welcom

The Galactic Center as a laboratory for theories of gravity and dark matter

The Galactic Center of the Milky Way, thanks to its proximity, allows to perform astronomical observations that investigate physical phenomena at the edge of astrophysics and fundamental physics. As such, it offers a unique laboratory to probe gravity, where one can not only test the basic predictions of General Relativity, but is also able to falsify theories that, over time, have been proposed to modify or extend General Relativity; to test different paradigms of dark matter; and to place constraints on putative models that have been formulated as alternatives to the standard black hole paradigm in General Relativity. In this review we provide a general overview of the history of observations of the Galactic Center, emphasizing the importance, in particular on the smallest-observable scales, that they had in opening a new avenue to improve our understanding of the underlying theory of gravity in the surrounding of a supermassive compact object.Comment: Comments and suggestions are welcome. Revised versio

Testing Horndeski gravity with S2 star orbit

We have explored a completely new and alternative way to restrict the parameter space of Horndeski theory of gravity. Using its Newtonian limit, it is possible to test the theory at a regime where, given its complexity and the small magnitude of the expected effects, it is poorly probed. At Newtonian level, it gives rise to a generalized Yukawa-like Newtonian potential which we have tested using S2 star orbit data. Our model adds five parameters to the General Relativity model, and the analysis constrains two of them with unprecedented precision to these energy scales, while only gives an exclusion region for the remaining parameters. We have shown the potential of weak-field tests to constrain Horndeski gravity opening, as a matter of fact, a new avenue that deserves to be further, and deeply, explored near in the future.Comment: 8 pages, 4 figures, 3 tables, 1 supplementary figure. Accepted for publication on MNRA

Value of information (VoI) for the chloride content in reinforced concrete bridges

The corrosion of reinforcement caused by chloride ingress significantly reduces the length of the service life of reinforced concrete bridges. Therefore, the condition of bridges is periodically inspected by specially trained engineers regarding the possible occurrence of reinforcement corrosion. Their main goal is to ensure that the structure can resist mechanical and environmental loads and offer a satisfactory level of safety and serviceability. In the course of assessment, measuring the chloride content, through which corrosion could be anticipated and prevented, presents a possible alternative to visual inspections and corrosion tests that can only indicate already existing corrosion. It is hard to determine the cost-effectiveness and actual value of chloride content measurements in a simple and straightforward way. Thus, the main aim of the paper was to study the value of newly gained information, which is obtained when a chloride content in reinforced concrete bridges is measured. This value was here analyzed through the pre-posterior analysis of the cost of measurement and repair, taking into account different types of exposure and material properties for a general case. The research focus was set on the initiation phase in which there are no visible damages. A relative comparison of costs is presented, where the cost of possible reactive/proactive repair was compared with the maximum cost of measurement, while the measurement is still cost effective. The analysis showed a high influence of the initial probability of depassivation on the maximum cost of the cost-effective measurement, as well as a nonreciprocal relation of the minimum cost of cost-effective reactive repair with the measurement accuracy.The author would like to acknowledge the financial and educational support from the COST TU 1402 Action (www.cost-tu1402.eu), received through the Training School grant

DESAIN PERANGKAT LUNAK PENGENALAN CITRA SIDlK JARI DENGAN MENGGUNAKAN METODE PARTIAL THINNING

Teknik pengenalan biometric adalah teknik identifikasi manusia berdasarkan pada karakteristik alaminya, baik fisiologis maupun perilaku. Salah satu yang paling terkenal adalah pengenalan sidik jari. Dalam pengenalan secara automatis menggunakan komputer, input yang berupa citra sidik jari tak dikenal dibandingkan dengan citra sidik jari yang sudah tersimpan dalam database. Beberapa permasalahan timbul dalam proses pembandingan berkaitan dengan ukuran citra serta posisi sidik jari input yang tidak selalu sama dengan citra yang tersimpan dalam database . Salah satu cara mengatasi masalah tersebut adalah dengan metode partial thinning. Metode ini memanfaatkan dua karakteristik utama sidik jari yaitu end point (titik ujung) dan bifurcation point (titik percabangan) sidik jari. Ada empat proses dalam metode partial thinning yaitu image pre-processing, image enhancement, minutiae extraction, danjingerprint matching. Pacta proses pertama dan kedua, citra input diolah sedemikian rupa sehingga dapat digunakan untuk proses selanjutnya. Pada proses ketiga, end points dan b(furcation points diidentifikasi, hasilnya kemudian dibandingkan dengan data dari database pada proses keempat. Dalam uji coba, aplikasi yang menggunakan metode ini dapat mengenali dua sidik jari yang sama meskipun pada salah satu citra dilakukan rotasi atau streching. Tingkat keberhasilan pengenalan juga dipengaruhi oleh noise