25,636 research outputs found
Una fundamentación jusnaturalista de los derechos humanos
Este artículo demuestra que, a menos que se reconozcan unas normas de Derecho
natural, no existe ningún fundamento para los derechos humanos, lo cual significa que el
jurista no podrá demostrar una razón válida para incorporarlos a la legislación positiva
donde no lo estén. Una norma de Derecho natural es aquella que se deduce, por una
correcta regla de inferencia lógico-deóntica, de cualquier norma positiva y, por lo tanto,
existe en todos los ordenamientos jurídicos, aunque no esté formulada. Este estudio se lleva a cabo por dos vías: la historia conceptual de la noción de derechos humanos y el análisis lógico-conceptual de los mismos.This paper proves that, unless certain natural law norms are recognized, human rights lack any foundation, which means that no lawyer will be able to show any compelling reason for them to be incorporated into positive law where they have not been legally sanctioned yet. A natural law norm is one which, in virtue of some valid deontic-logic inference rules, can be deduced from any positive norm and hence exists in every legal system, even if not formally enacted. Our study contains to parts: a conceptual-historical account of the notion of human righs and a logical and conceptual analysis thereof
Efficient generation and sorting of orbital angular momentum eigenmodes of light by thermally tuned q-plates
We present methods for generating and for sorting specific orbital angular
momentum (OAM) eigenmodes of a light beam with high efficiency, using a liquid
crystal birefringent plate with unit topological charge, known as \qo{q-plate}.
The generation efficiency has been optimized by tuning the optical retardation
of the q-plate with temperature. The measured OAM eigenmodes
generation efficiency from an input TEM beam was of 97%. Mode sorting of
the two input OAM eigenmodes was achieved with an efficiency of 81%
and an extinction-ratio (or cross-talk) larger than 4.5:1.Comment: 4 pages, 3 Figures and 1 table. Submitte
Partial spin freezing in the quasi-two-dimensional La2(Cu,Li)O4
In conventional spin glasses, the magnetic interaction is not strongly
anisotropic and the entire spin system freezes at low temperature. In
La2(Cu,Li)O4, for which the in-plane exchange interaction dominates the
interplane one, only a fraction of spins with antiferromagnetic correlations
extending to neighboring planes become spin-glass. The remaining spins with
only in-plane antiferromagnetic correlations remain spin-liquid at low
temperature. Such a novel partial spin freezing out of a spin-liquid observed
in this cold neutron scattering study is likely due to a delicate balance
between disorder and quantum fluctuations in the quasi-two dimensional S=1/2
Heisenberg system.Comment: 4 pages, 4 figure
Comparison between the Torquato-Rintoul theory of the interface effect in composite media and elementary results
We show that the interface effect on the properties of composite media
recently proposed by Torquato and Rintoul (TR) [Phys. Rev. Lett. 75, 4067
(1995)] is in fact elementary, and follows directly from taking the limit in
the dipolar polarizability of a coated sphere: the TR ``critical values'' are
simply those that make the dipolar polarizability vanish. Furthermore, the new
bounds developed by TR either coincide with the Clausius-Mossotti (CM) relation
or provide poor estimates. Finally, we show that the new bounds of TR do not
agree particularly well with the original experimental data that they quote.Comment: 13 pages, Revtex, 8 Postscript figure
Business Cycle Fluctuations and Private Savings in OECD Countries: A Panel Data Analysis
We investigate the cyclicality of the private savings to GDP ratio for a panel of 19 OECD countries over the period 1971-2009. We find robust evidence that the private savings ratio is countercyclical. Three theories unambiguously predict a higher private savings ratio during recessions: a Ricardian offset effect, the presence of credit constraints, and precautionary savings. We find evidence only for the latter theory. Our estimations take into account a large number of econometric complications: persistence in the savings ratio, endogeneity of the regressors, cross-country parameter heterogeneity, cross-sectional dependence, stationarity issues, omitted variables, and instrument strength
A wavelet-based ECG delineation algorithm for 32-bit integer online processing
<p>Abstract</p> <p>Background</p> <p>Since the first well-known electrocardiogram (ECG) delineator based on Wavelet Transform (WT) presented by Li <it>et al. </it>in 1995, a significant research effort has been devoted to the exploitation of this promising method. Its ability to reliably delineate the major waveform components (mono- or bi-phasic P wave, QRS, and mono- or bi-phasic T wave) would make it a suitable candidate for efficient online processing of ambulatory ECG signals. Unfortunately, previous implementations of this method adopt non-linear operators such as <it>root mean square </it>(RMS) or floating point algebra, which are computationally demanding.</p> <p>Methods</p> <p>This paper presents a 32-bit integer, linear algebra advanced approach to online QRS detection and P-QRS-T waves delineation of a single lead ECG signal, based on WT.</p> <p>Results</p> <p>The QRS detector performance was validated on the MIT-BIH Arrhythmia Database (sensitivity Se = 99.77%, positive predictive value P+ = 99.86%, on 109010 annotated beats) and on the European ST-T Database (Se = 99.81%, P+ = 99.56%, on 788050 annotated beats). The ECG delineator was validated on the QT Database, showing a mean error between manual and automatic annotation below 1.5 samples for all fiducial points: P-onset, P-peak, P-offset, QRS-onset, QRS-offset, T-peak, T-offset, and a mean standard deviation comparable to other established methods.</p> <p>Conclusions</p> <p>The proposed algorithm exhibits reliable QRS detection as well as accurate ECG delineation, in spite of a simple structure built on integer linear algebra.</p
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