Entropy and Poincar\'e recurrence from a geometrical viewpoint

We study Poincar\'e recurrence from a purely geometrical viewpoint. We prove that the metric entropy is given by the exponential growth rate of return times to dynamical balls. This is the geometrical counterpart of Ornstein-Weiss theorem. Moreover, we show that minimal return times to dynamical balls grow linearly with respect to its length. Finally, some interesting relations between recurrence, dimension, entropy and Lyapunov exponents of ergodic measures are given.Comment: 11 pages, revised versio

Trajectory Surface Hopping Study of the Li + Li2(X1Σg+) Dissociation Reaction

Trajectory surface hopping calculations are reported for the Li + Li2(X1Σg+) dissociation reaction over the range of translational energies 13 ≤ Etr/kcal mol-1 ≤ 80. Both potential energy surfaces for ground doublet Li3, which have been modeled from the double many-body expansion method (DMBE III), have been employed in the dynamics calculations. For the initial internal state (v = 0, j = 10), the behavior of the dissociative cross sections as a function of translational energy shows that nonadiabatic effects are important over the whole range of energies studied. Concerning the role of initial vibration, it has been found that, for Etr = 25 kcal mol-1 and j = 10, the adiabatic dissociative cross sections are enhanced as v increases from 0 to 20, while the nonadiabatic ones just slightly increase with the vibrational quantum number

Integrating social concerns into electricity planning

This paper deals with the complexity of the social issues surrounding electricity planning. A methodology is presented establishing a possible way of allocating weights to the most important social impacts of the electricity generation options and extending these results to the evaluation of future electricity plans. The process combined Delphi method with the Analytic Hierarchy Process, for the pairwise comparison of the electricity generation technologies against the social criteria. A social impact score was then derived and assigned to each technology. In order to obtain a final ranking of future feasible plans, these overall social scores of the electricity generation alternatives were aggregated using an additive function. The final output of the social analysis is an Average Social Index of each possible electricity generation mix

The impacts of wind power on power systems operation

The wind power sector is growing rapidly in Portugal and the National objectives for energy include a significant increase of wind power during the next years. The large penetration of wind power in Portugal will influence significantly the energy system cost, but it seems also essential to materialize the international energetic and environmental commitments. This paper focuses on the impact of large scale wind scenarios on the power system operation. CO2 abatement potential is estimated along with the effects on the operating costs of thermal power plants. Simulations for different wind scenarios were run for 2016, assuming the possibility of exports. According to the results, it seems that about 20% of wind power penetration may be achieved in Portugal with minor losses of efficiency of the global system

Multidrug-Resistant Klebsiella Pneumoniae Meningitis Successfully Treated with Intrathecal Colistin

Background: Multidrug-resistant (MDR) gram negative bacteria meningitis has become a clinical entity with increasing importance in recent years. Intrathecal colistin (ITH) has been used in the treatment of this cases. Aims: To report one case of MDR Klebsiella pneumoniae meningitis and ventriculitis successfully treated with ITH colistin. Case Report: Nine months old boy, born at 28 weeks of gestational age, diagnosed with neonatal meningitis, complicated with tetraventricular hydrocephalus requiring ventriculo-peritoneal shunt (VPS) placement and multiple shunt revisions. Admitted for worsening hydrocephalus. Cerebrospinal fluid (CSF) cultures were positive for extended-spectrum β-lactamase (ESBL) Klebsiella pneumoniae, only sensitive to meropenem and amikacin. Intravenous meropenen was started but CSF cultures remained positive and shunt device could not be removed. Although susceptibility to colistin was not available, on day 24 intrathecal colistin(4mg/day) was started through an external shunt. CSF white blood cell count improved and cultures became negative. Colistin was stopped after 19 days because of CSF pleocitosis and meropenen maintained for a total of 2 months with clinical improvement. Conclusion: In Klebsiella pneumoniae meningitis with ventriculitis, ITH colistin can be considered a safe, effective, and practicable alternative treatment when parental administration fails.info:eu-repo/semantics/publishedVersio

An overview of the Portuguese wind power sector

In the following paper the present situation of the electricity production from Renewable energy Sources (RES) in Portugal is analysed, giving particular attention to the wind power sector due to its increasing importance. The evolution of the electricity system is presented along with the strategies for the sector, and future prospects for the RES. Although the high interest of private companies in the wind sector the administrative and grid barriers represent major obstacles to the wind power development. The problem of the wind intermittency and uncertainty is also discussed. The improvement of interconnection capacity and the increase of power reserve are identified as key requirements for ensuring the security of supply. A clear comprehension of all these aspects is fundamental to aim for an integrated multidimensional wind power planning.(undefined

Electricity power planning: the role of wind energy

Combining energy efficiency with renewable energy sources constitutes a key strategy for a sustainable future. The wind power sector stands out as a fundamental element for the achievement of the European renewable objectives and Portugal is no exception to the increase of the wind energy for the electricity generation. This work proposes an optimization model for the long range electricity power planning in a system similar to the Portuguese one, where the expected impacts of the increasing installed wind power on the operating performance of thermal power plants are taken into account. The main results indicate that the increasing penetration of wind power in the electricity system will have significant effects on the combined cycle gas power plants operation and on the theoretically expected cost reduction and environmental gains. This research demonstrated the need to address the impact that energy sources with variable output may have, not only on the short-term operational planning, but especially on the medium to long range planning activities, in order to meet the strategic objectives for the energy sector.Fundação para a Ciência e Tecnologia (FCT)COMPETE – Programa Operacional Factores de Competitividade under Research Project PTDC/SEN-ENR/099578/200

Mycobacterium Tuberculosis Prosthesis Joint Infection

info:eu-repo/semantics/publishedVersio