The ideal of the certainty in law: the skin and the heart of law

The doubt about certainty like an absolute value in law and as an ideal full in legal system (argument about impossibility) is a controversial fact in contemporary legal theory. In this text I examine some contemporary doctrines about the classic understanding (in critical sense) of this ideal. I have selected the most representative doctrines: doctrine about "open texture of Law" (H.L.A. Hart), starting point in this discussion; doctrine about "Il Diritto mite" (G. Zagrebelsky), from the continental European legal tradition at present; and doctrine about "vagueness in Law" (T.A.O. Endicott), this doctrine is the most recent, from the Anglo-Saxon legal tradition. Finally, in Conclusions, I analyze if this doubt (argument about impossibility) contaminates (in some sense) to the concept of law or to the characteristics that describe law in the contemporary Constitutional State

X-Shooter study of accretion in ρ\rho-Ophiucus: very low-mass stars and brown dwarfs

We present new VLT/X-Shooter optical and NIR spectra of a sample of 17 candidate young low-mass stars and BDs in the rho-Ophiucus cluster. We derived SpT and Av for all the targets, and then we determined their physical parameters. All the objects but one have M*<0.6 Msun, and 8 have mass below or close to the hydrogen-burning limit. Using the intensity of various emission lines present in their spectra, we determined the Lacc and Macc for all the objects. When compared with previous works targeting the same sample, we find that, in general, these objects are not as strongly accreting as previously reported, and we suggest that the reason is our more accurate estimate of the photospheric parameters. We also compare our findings with recent works in other slightly older star-forming regions to investigate possible differences in the accretion properties, but we find that the accretion properties for our targets have the same dependence on the stellar and substellar parameters as in the other regions. This leads us to conclude that we do not find evidence for a different dependence of Macc with M* when comparing low-mass stars and BDs. Moreover, we find a similar small (1 dex) scatter in the Macc-M* relation as in some of our recent works in other star-forming regions, and no significant differences in Macc due to different ages or properties of the regions. The latter result suffers, however, from low statistics and sample selection biases in the current studies. The small scatter in the Macc-M* correlation confirms that Macc in the literature based on uncertain photospheric parameters and single accretion indicators, such as the Ha width, can lead to a scatter that is unphysically large. Our studies show that only broadband spectroscopic surveys coupled with a detailed analysis of the photospheric and accretion properties allows us to properly study the evolution of disk accretion rates.Comment: accepted for publication in Astronomy & Astrophysics. Abstract shortened to fit arXiv constraint

Contemporaneous broad-band photometry and Hα\alpha observations of T Tauri stars

The study of contemporaneous variations of the continuum flux and emission lines is of great importance to understand the different astrophysical processes at work in T Tauri stars. In this paper we present the results of a simultaneous $BVRI$ and H$\alpha$ photometric monitoring, contemporaneous to medium-resolution spectroscopy of six T Tauri stars in the Taurus-Auriga star forming region. We have characterized the H$\alpha$ photometric system using synthetic templates and the contemporaneous spectra of the targets. We show that we can achieve a precision corresponding to 2$-$3 \AA\ in the H$\alpha$ equivalent width, in typical observing conditions. The spectral analysis has allowed us to determine the basic stellar parameters and the values of quantities related to the accretion. In particular, we have measured a significant veiling only for the three targets with the strongest H$\alpha$ emission (T Tau, FM Tau, and DG Tau). The broad-band photometric variations are found to be in the range 0.05$-$0.70 mag and are often paired to variations in the H$\alpha$ intensity, which becomes stronger when the stellar continuum is weaker. In addition, we have mostly observed a redder $V-I$ and a bluer $B-V$ color as the stars become fainter. For most of the targets, the timescales of these variations seem to be longer than the rotation period. One exception is T Tau, for which the broad-band photometry varies with the rotation period. The most plausible interpretation of these photometric and H$\alpha$ variations is that they are due to non-stationary mass accretion onto the stars, but rotational modulation can play a major role in some cases.Comment: 21 pages, 11 figures, accepted for publication in Acta Astronomic

The Chamaeleon II low-mass star-forming region: radial velocities, elemental abundances, and accretion properties

Radial velocities, elemental abundances, and accretion properties of members of star-forming regions (SFRs) are important for understanding star and planet formation. While infrared observations reveal the evolutionary status of the disk, optical spectroscopy is fundamental to acquire information on the properties of the central star and on the accretion characteristics. 2MASS archive data and the Spitzer c2d survey of the Chamaeleon II dark cloud have provided disk properties of a large number of young stars. We complement these data with spectroscopy with the aim of providing physical stellar parameters and accretion properties. We use FLAMES/UVES+GIRAFFE observations of 40 members of Cha II to measure radial velocities through cross-correlation technique, Li abundances by means of curves of growth, and for a suitable star elemental abundances of Fe, Al, Si, Ca, Ti, and Ni using the code MOOG. From the equivalent widths of the Halpha, Hbeta, and the HeI-5876, 6678, 7065 Angstrom emission lines, we estimate the mass accretion rates, dMacc/dt, for all the objects. We derive a radial velocity distribution for the Cha II stars (=11.4+-2.0 km/s). We find dMacc/dt prop. to Mstar^1.3 and to Age^(-0.82) in the 0.1-1.0 Msun mass regime, and a mean dMacc/dt for Cha II of ~7*10^(-10) Msun/yr. We also establish a relationship between the HeI-7065 Angstrom line emission and the accretion luminosity. The radial velocity distributions of stars and gas in Cha II are consistent. The spread in dMacc/dt at a given stellar mass is about one order of magnitude and can not be ascribed entirely to short timescale variability. Analyzing the relation between dMacc/dt and the colors in Spitzer and 2MASS bands, we find indications that the inner disk changes from optically thick to optically thin at dMacc/dt~10^(-10) Msun/yr. Finally, the disk fraction is consistent with the age of Cha II.Comment: 21 Pages, 15 Figures, 7 Tables. Accepted for publication in Astronomy and Astrophysics. Abstract shortene

Del Estado-nación de Derecho al Estado de Derecho postnacional. Análisis de la tesis de L. Ferrajoli sobre la desnacionalización de la teoría de los derechos

Publicad

Dudas e incertidumbres sobre los Derechos culturales

Programa Consolider "El tiempo de los derechos" (HURI-AGE

Sobre la indeterminación del derecho y la ley constitucional. El caso del término «nacionalidades» como concepto jurídico indeterminado

SUMARIO: Planteamiento: 1. Notas acerca de la indeterminación del Derecho y el operador jurídico. 2. En torno a la indeterminación de la Ley Constitiucional y el término jurídico «nacionalidades»Publicad

Crossing the Gould Belt in the Orion vicinity

We present a study of the large-scale spatial distribution of 6482 RASS X-ray sources in approximately 5000 deg^2 in the direction of Orion. We examine the astrophysical properties of a sub-sample of ~100 optical counterparts, using optical spectroscopy. This sub-sample is used to investigate the space density of the RASS young star candidates by comparing X-ray number counts with Galactic model predictions. We characterize the observed sub-sample in terms of spectral type, lithium content, radial and rotational velocities, as well as iron abundance. A population synthesis model is then applied to analyze the stellar content of the RASS in the studied area. We find that stars associated with the Orion star-forming region do show a high lithium content. A population of late-type stars with lithium equivalent widths larger than Pleiades stars of the same spectral type (hence younger than ~70-100 Myr) is found widely spread over the studied area. Two new young stellar aggregates, namely "X-ray Clump 0534+22" (age~2-10 Myr) and "X-ray Clump 0430-08" (age~2-20 Myr), are also identified. The spectroscopic follow-up and comparison with Galactic model predictions reveal that the X-ray selected stellar population in the direction of Orion is characterized by three distinct components, namely the clustered, the young dispersed, and the widespread field populations. The clustered population is mainly associated with regions of recent or ongoing star formation and correlates spatially with molecular clouds. The dispersed young population follows a broad lane apparently coinciding spatially with the Gould Belt, while the widespread population consists primarily of active field stars older than 100 Myr. We expect the "bi-dimensional" picture emerging from this study to grow in depth as soon as the distance and the kinematics of the studied sources will become available from the future Gaia mission.Comment: 17 pages, 13 figures, 4 tables. Accepted for publication in Astronomy and Astrophysics. Abstract shortene

El derecho a la identidad cultural: Criterios de fundamentación

El derecho a la identidad cultural es un derecho controvertido en nuestras sociedades contemporáneas. La afirmación de este derecho supone replantear algunas de las nociones del Estado de Derecho y de la teoría de los derechos, para poder dar cabida a las cuestiones de la identidad. En relación a lo cual, actualmente, autores como P. Häberle hablan de la “cultura” como cuarto elemento del Estado Constitucional. Esta visión contradice la perspectiva que pregona la teoría clásica del Estado, basada en la Staatsnation, que reduce los elementos configuradores del Estado a los tradicionales de territorio, población y poder. Con esas premisas, desde este texto, se abordan un conjunto de criterios que son susceptibles de fundamentar el derecho a la identidad cultural, tanto desde el punto de vista moral (fundamentación moral: vinculada a la dignidad humana) como desde la perspectiva estrictamente normativa (justificación jurídica: como derecho normativo de libertad y derecho normativo de igualdad).The right to cultural identity is a controversial right within modern-day societies. Affirming this right entails rethinking a number of concepts concerning the Constitutional State and the theory of rights in order to find a place for questions of identity. In this regard, current authors such as P. Häberle speak of “culture” as the fourth element of the Constitutional State. This view opposes the perspective that espouses the classical theory of State, based on the Staatsnation, which reduces the elements that make up the State to the traditional aspects of territory, population and power. With these premises, this paper addresses a series of criteria that may provide the foundation of the right to cultural identity, both from a moral point of view (moral foundation: linked to human dignity) and from a strictly legal perspective (legal justification: as a legal right to freedom and a legal right to equality)