Search results for "WAVES"
showing 10 items of 1766 documents
Immigrant Detention Centres in Spain: a critical assessment
2012
This paper presents a critical examination of the management of irregular migration flows in Spain and the legal principles and administrative practices implemented by the State in the process of expulsion that legitimise the existence of Immigrant Detention Centres (CIE). It also provides a description of the current situation of the CIE, and reports on the most recent proposals made by the Spanish government to improve the management of CIE in response to pressure exerted by civil society organisations, especially after public protests regarding the death of two inmates in December 2011 and January 2012.
Trapped Ion Oscillation Frequencies as Sensors for Spectroscopy
2010
The oscillation frequencies of charged particles in a Penning trap can serve as sensors for spectroscopy when additional field components are introduced to the magnetic and electric fields used for confinement. The presence of so-called "magnetic bottles" and specific electric anharmonicities creates calculable energy-dependences of the oscillation frequencies in the radiofrequency domain which may be used to detect the absorption or emission of photons both in the microwave and optical frequency domains. The precise electronic measurement of these oscillation frequencies therefore represents an optical sensor for spectroscopy. We discuss possible applications for precision laser and microw…
The XMM-Newton Extended Survey of the Taurus Molecular Cloud (XEST)
2007
(abridged:) The XMM-Newton Extended Survey of the Taurus Molecular Cloud (XEST) surveys the most populated ~5 square degrees of the Taurus star formation region, using the XMM-Newton X-ray observatory to study the thermal structure, variability, and long-term evolution of hot plasma, to investigate the magnetic dynamo, and to search for new potential members of the association. Many targets are also studied in the optical, and high-resolution X-ray grating spectroscopy has been obtained for selected bright sources. The X-ray spectra have been coherently analyzed with two different thermal models (2-component thermal model, and a continuous emission measure distribution model). We present ov…
Topological polarization, dual invariants, and surface flat band in crystalline insulators
2020
We describe a three-dimensional crystalline topological insulator (TI) phase of matter that exhibits spontaneous polarization. This polarization results from the presence of (approximately) flat bands on the surface of such TIs. These flat bands are a consequence of the bulk-boundary correspondence of polarized topological media, and contrary to related nodal line semimetal phases also containing surface flat bands, they span the entire surface Brillouin zone. We also present an example Hamiltonian exhibiting a Lifshitz transition from the nodal line phase to the TI phase with polarization. Utilizing elasticity tetrads, we show a complete classification of 3D crystalline TI phases and invar…
Engineered surface waves in hyperbolic metamaterials
2013
We analyzed surface-wave propagation that takes place at the boundary between a semi-infinite dielectric and a multilayered metamaterial, the latter with indefinite permittivity and cut normally to the layers. Known hyperbolization of the dispersion curve is discussed within distinct spectral regimes, including the role of the surrounding material. Hybridization of surface waves enable tighter confinement near the interface in comparison with pure-TM surface-plasmon polaritons. We demonstrate that the effective-medium approach deviates severely in practical implementations. By using the finite-element method, we predict the existence of long-range oblique surface waves. This research was fu…
Phase retrieval of vitreous floaters: simulation experiment
2020
Knowledge of the structure of vitreous floaters is crucial to evaluate the need for surgical removal of these floaters. We simulated the phase retrieval of microstructures simulating vitreous floaters by an algorithm PhaseLift and investigate the effects of various parameters on the retrieved phase. The object under test was modulated and the coded diffraction patterns were calculated. Next, PhaseLift was used to retrieve the phase. In the current study, we simulate the effect of Gaussian and Poison noise on the phase retrieval of pure phase objects. We apply an iterative algorithm PhaseLift for phase retrieval as this algorithm requires a very few modulating masks and is able to retrieve t…
Theoretical and Experimental Study of Polarization Modulation Instability in All-Normal Dispersion Photonic Crystal Fibers
2018
Experimental observation of polarization modulation instability in all-normal dispersion photonic crystal fibers is reported. Stokes and anti-Stokes sidebands with spectral shift of 40 nm were observed when the fiber was pumped at 1064 nm. Experimental results are baked by a vectorial four-wave mixing model.
EXTRACORPOREAL SHOCK WAVE THERAPY (ESWT) IN CHRONIC LOW BACK PAIN: A SYSTEMATIC REVIEW OF RANDOMIZED CLINICAL TRIALS
2020
Background: Extracorporeal Shock Wave Therapy (ESWT) has become a popular tool to treat musculoskeletal disorders and chronic low back pain. Aim of the study: To review the current scientific literature and assess the utility of ESWT in treating chronic low back pain. Methods: This systematic review was conducted from November 2019 to January 2020. Its purpose was to determine what the effectiveness is of the various forms of ESWT for the treatment of chronic low back pain. The critical review of the literature on the use of ESWT in chronic low back was made using the scientifically recognized medical databases PubMed, MEDLINE, Physiotherapy Evidence Database (PEDro) and Web of Science Core…
Effect of the submerged vegetation distribution on flow characteristics and lateral dispersion: Experimental analysis at the apex section of a meande…
2020
Understanding of how the vegetation distribution influences flow patterns and turbulence structure is extremely important to analyse environmental processes as the sediment transport and the mixing of transported quantities. In the present paper attention is focused on the effect of flexible vegetation on flow characteristics and dispersion processes at the apex section of a large-amplitude meandering bend. The analysis is conducted with the aid of data collected in a laboratory meandering flume both in the absence of vegetation on the bed and in the presence of real and flexible vegetation on the bed. Results show that the presence of vegetation affects both the lateral dispersion coeffici…
ULTRASONIC WAVES IN HETEROGENEOUS MATERIALS - MECHANICAL CHARACTERIZATION OF HETEROGENEOUS MATERIALS BY MEANS OF ULTRASONIC TESTS AND NUMERICAL MODEL…
2014
This Ph.D thesis treats the propagation of ultrasonic waves in heterogeneous materials. It is widely known how waves propagate in homogeneous materials like metallic ones. But very few aspects are known about the propagation in the heterogeneous materials because of the complex behavior regarding these materials. The heterogeneity can be related with the intrinsic properties, elastic and chemical, of each phase of the material, or with the periodic or random arrangement of inclusions of constant or different shapes. Concrete is a common case. In this work the first chapter gives a description of the main characteristics of heterogeneous materials.. In the second one, the methods of inspecti…