Wormholes and Ringholes in a Dark-Energy Universe

The effects that the present accelerating expansion of the universe has on the size and shape of Lorentzian wormholes and ringholes are considered. It is shown that, quite similarly to how it occurs for inflating wormholes, relative to the initial embedding-space coordinate system, whereas the shape of the considered holes is always preserved with time, their size is driven by the expansion to increase by a factor which is proportional to the scale factor of the universe. In the case that dark energy is phantom energy, which is not excluded by present constraints on the dark-energy equation of state, that size increase with time becomes quite more remarkable, and a rather speculative scenario is here presented where the big rip can be circumvented by future advanced civilizations by utilizing sufficiently grown up wormholes and ringholes as time machines that shortcut the big-rip singularity.Comment: 11 pages, RevTex, to appear in Phys. Rev.

Lattice dynamics of mixed semiconductors (Be,Zn)Se from first-principles calculations

Vibration properties of Zn(1-x)Be(x)Se, a mixed II-VI semiconductor haracterized by a high contrast in elastic properties of its pure constituents, ZnSe and BeSe, are simulated by first-principles calculations of electronic structure, lattice relaxation and frozen phonons. The calculations within the local density approximation has been done with the Siesta method, using norm-conserving pseudopotentials and localized basis functions; the benchmark calculations for pure endsystems were moreover done also by all-electron WIEN2k code. An immediate motivation for the study was to analyze, at the microscopic level, the appearance of anomalous phonon modes early detected in Raman spectra in the intermediate region (20 to 80%) of ZnBe concentration. This was early discussed on the basis of a percolation phenomenon, i.e., the result of the formation of wall-to-wall --Be--Se-- chains throughout the crystal. The presence of such chains was explicitly allowed in our simulation and indeed brought about a softening and splitting off of particular modes, in accordance with experimental observation, due to a relative elongation of Be--Se bonds along the chain as compared to those involving isolated Be atoms. The variation of force constants with interatomic distances shows common trends in relative independence on the short-range order.Comment: 11 pages, 10 figures, to be published in Phys. Rev.

Quantum time machine

The continuation of Misner space into the Euclidean region is seen to imply the topological restriction that the period of the closed spatial direction becomes time-dependent. This restriction results in a modified Lorentzian Misner space in which the renormalized stress-energy tensor for quantized complex massless scalar fields becomes regular everywhere, even on the chronology horizon. A quantum-mechanically stable time machine with just the sub-microscopic size may then be constructed out of the modified Misner space, for which the semiclassical Hawking's chronology protection conjecture is no longer an obstruction.Comment: 6 pages, RevTe

Magnetoplasmonic Interferometers and Applications

Comunicación presentada en el 2nd Early Stage Researchers Workshop in Nanoscience, celebrado en Madrid el 28 y 29 de junio de 2012.Surface plasmons polaritons (SPP) are evanescent waves that propagate along a dielectric-metal interface. They can be confined in subwavelength metal structures, i.e. below the diffraction limit, which leads to many possible applications, including miniaturized optical devices. Within that context, the development of active plasmonics is important to achieve nanophotonic devices with advanced functionalities. This requires a system where the plasmon properties can be manipulated using an external agent. Among the different control agents considered so far, the magnetic field seems a promising candidate, since it is able to modify the dispersion relation of SPP at reasonable magnetic field strengths, and with a high switching speed. This modulation comes from the non-diagonal elements of the dielectric tensor, εij, appearing when the magnetic field is turned on. For noble metals, the ones typically used in plasmonics, these elements are proportional to the applied magnetic field but, unfortunately, very small at field values reasonable for developing applications. On the other hand, ferromagnetic metals have sizeable εij values at small magnetic fields (proportional to their magnetization), but are optically too absorbent. A smart system to develop magnetic field tunable plasmonic devices is the use of multilayers of noble and ferromagnetic metals. That is the framework of the present work, where we analyze the magnetic field induced SPP wavevector modulation (Ak) in Au/Co/Au films as a function of the wavelength and its possible application as a sensor.N

High spatial resolution optical imaging of the multiple T Tauri system LkH{\alpha} 262/LkH{\alpha} 263

We report high spatial resolution i' band imaging of the multiple T Tauri system LkH$\alpha$ 262/LkH$\alpha$ 263 obtained during the first commissioning period of the Adaptive Optics Lucky Imager (AOLI) at the 4.2 m William Herschel Telescope, using its Lucky Imaging mode. AOLI images have provided photometry for each of the two components LkH$\alpha$ 263 A and B (0.41 arcsec separation) and marginal evidence for an unresolved binary or a disc in LkH$\alpha$ 262. The AOLI data combined with previously available and newly obtained optical and infrared imaging show that the three components of LkH$\alpha$ 263 are co-moving, that there is orbital motion in the AB pair, and, remarkably, that LkH$\alpha$ 262-263 is a common proper motion system with less than 1 mas/yr relative motion. We argue that this is a likely five-component gravitationally bounded system. According to BT-settl models the mass of each of the five components is close to 0.4 M$_{\odot}$ and the age is in the range 1-2 Myr. The presence of discs in some of the components offers an interesting opportunity to investigate the formation and evolution of discs in the early stages of multiple very low-mass systems. In particular, we provide tentative evidence that the disc in 263C could be coplanar with the orbit of 263AB.Comment: 11 pages, 7 figures, Accepted 2016 May

Accretions of Various Types of Dark Energies onto Morris-Thorne Wormhole

In this work, we have studied accretion of the dark energies onto Morris-Thorne wormhole. For quintessence like dark energy, the mass of the wormhole decreases and phantom like dark energy, the mass of wormhole increases. We have assumed two types of dark energy like variable modified Chaplygin gas (VMCG) and generalized cosmic Chaplygin gas (GCCG). We have found the expression of wormhole mass in both cases. We have found the mass of the wormhole at late universe and this is finite. For our choices the parameters and the function $B(a)$, these models generate only quintessence dark energy (not phantom) and so wormhole mass decreases during evolution of the universe. Next we have assumed 5 kinds of parametrizations of well known dark energy models. These models generate both quintessence and phantom scenarios. So if these dark energies accrete onto the wormhole, then for quintessence stage, wormhole mass decreases upto a certain value (finite value) and then again increases to infinite value for phantom stage during whole evolution of the universe. We also shown these results graphically.Comment: 9 pages, 7 figures. arXiv admin note: text overlap with arXiv:1112.615

Developing a Business Application with BPM and MDE

In this paper we have designed an architecture for the generation of a business application, that allows to business users to adapt their processes to the constant change. At the moment all the architectures based to a great extent on SOA allow to modify the processes in a short period of time, but we go beyond and give the possibility to the business user of modifying their processes. To design this architecture, we rely on the fundamental use of two technologies: BPM (Business Process Modeling) and MDE (Model Driven Engineering). Inside these technologies we focus on the creation of a business process notation extended from BPMN that is agile, easy to learn and design, and capable to provide semantic information about the process. Therefore this notation allows business process to modify their processes to achieve the proposed goal

Evaluación del uso apropiado de medicamentos en atención primaria. ¿Cómo se puede mejorar?

IntroducciónEl proceso de medicación de un paciente abarca la identificación de su problema de salud, la prescripción para esa indicación por parte del médico, la dispensación farmacéutica y el consumo del fármaco. Los estudios de utilización de medicamentos analizan dicho proceso con el de detectar los factores que alteran el uso correcto de los fármacos.ObjetivoEvaluar la calidad de la prescripción de ciertos medicamentos en atención primaria en función de la indicación para la que fueron prescritos, detectando aquellas características de los pacientes, médicos prescriptores, centros de atención primaria y áreas de salud que influyen en su uso inapropiado.MétodoEstudio prescripción-indicación basado en la estimación de modelos multinivel con bases de datos individualizadas de las prescripciones, que contienen características de las prescripciones, pacientes, médicos, centros de salud y áreas de salud de pertenencia. Estos modelos suponen un avance en este tipo de estudios ya que permiten analizar de forma conjunta la información de distintos niveles y estimar sus respectivas «cuotas de responsabilidad» en la inadecuación de la prescripción.DiscusiónAdemás de su interés metodológico, que puede guiar estudios posteriores, el principal interés del trabajo estriba en su carácter pionero en la utilización masiva de microdatos poblacionales para evaluar la calidad de la prescripción, que proceden de las historias clínicas informatizadas de atención primaria.IntroductionThe process of medicating a patient embraces the identification of the health problem, the doctor’ s prescription to treat this indication, the dispensing of the medicine and its consumption. The studies of use of medicine analyse this process in order to detect those factors that impinge on the correct use of medicines.ObjectiveTo evaluate the quality of the prescription of certain primary care medicines as a function of the indication for which they were prescribed, detecting those features of the patients, prescribing doctors, primary care centre and health district that affect their inappropriate use.MethodPrescription-indication study based on the calculation of multiple-level models with individualised data bases for the prescriptions. These include characteristics of the prescriptions, patients, doctors, health centres and the health district involved. These models are a step forward in this kind of study, in that they enable analysis of the information from different levels at the same time as calculation of the respective «degrees of responsibility» for inadequacies of prescription.DiscussionApart from its methodological originality, which may serve for subsequent studies, the main interest of this study lies in the pioneering nature of its massive use of population micro-data to evaluate prescription quality. These data are taken from the computerised clinical records in primary care

Prediction of Antimalarial Drug-Decorated Nanoparticle Delivery Systems with Random Forest Models

Drug-decorated nanoparticles (DDNPs) have important medical applications. The current work combined Perturbation Theory with Machine Learning and Information Fusion (PTMLIF). Thus, PTMLIF models were proposed to predict the probability of nanoparticle–compound/drug complexes having antimalarial activity (against Plasmodium). The aim is to save experimental resources and time by using a virtual screening for DDNPs. The raw data was obtained by the fusion of experimental data for nanoparticles with compound chemical assays from the ChEMBL database. The inputs for the eight Machine Learning classifiers were transformed features of drugs/compounds and nanoparticles as perturbations of molecular descriptors in specific experimental conditions (experiment-centered features). The resulting dataset contains 107 input features and 249,992 examples. The best classification model was provided by Random Forest, with 27 selected features of drugs/compounds and nanoparticles in all experimental conditions considered. The high performance of the model was demonstrated by the mean Area Under the Receiver Operating Characteristics (AUC) in a test subset with a value of 0.9921 ± 0.000244 (10-fold cross-validation). The results demonstrated the power of information fusion of the experimental-centered features of drugs/compounds and nanoparticles for the prediction of nanoparticle–compound antimalarial activity. The scripts and dataset for this project are available in the open GitHub repository.This research and the APC were funded by Consolidation and Structuring of Competitive Research Units—Competitive Reference Groups (ED431C 2018/49) funded by the Ministry of Education, University and Vocational Training of Xunta de Galicia endowed with EU FEDER funds

Magnetoplasmonic design rules for active magneto-optics

Light polarization rotators and non-reciprocal optical isolators are essential building blocks in photonics technology. These macroscopic passive devices are commonly based on magneto-optical Faraday and Kerr polarization rotation. Magnetoplasmonics - the combination of magnetism and plasmonics - is a promising route to bring these devices to the nanoscale. We introduce design rules for highly tunable active magnetoplasmonic elements in which we can tailor the amplitude and sign of the Kerr response over a broad spectral range