588 research outputs found
Les mariages clandestins: impasse disciplinaire, scandale ou moteur de la réflexion doctrinale?
The history of the formalization of marriage law in the Latin medieval West is very much like a series of normative tensions. Although the conflicts of norms cannot be restricted to theological and legal controversies, their interest lies in the fact that they sometimes gave rise to the expression of contradictory norms, depending on the forum at stake. It was more particularly the case when it came to the question of settling the moral and judiciary issues in connexion with the hierarchical status of clandestine marriages and that of public ones, or the one of a “sexual intercourse followed by words of future” and that of a marriage contracted by “words of present”. Which of these processes guaranteed a « true » marriage ? And according to which normative references ? The different solutions provided by canonical doctrine, theology, the manuals for parish priests and confessors or even synodal statutes enable us to assess the different goals of the clerics concerned by matrimonial issues. Much is at stake, because what is concerned is the salvation of the laity and the balance of the whole society. These normative tensions sometimes led to conceptual and lexical evolutions, but they also entailed certain forms of competition that could undermine the usual means of social regulation, which the actors of matrimonial could sometimes take advantage of
Numerical Solutions of Matrix Differential Models using Cubic Matrix Splines II
This paper presents the non-linear generalization of a previous work on
matrix differential models. It focusses on the construction of approximate
solutions of first-order matrix differential equations Y'(x)=f(x,Y(x)) using
matrix-cubic splines. An estimation of the approximation error, an algorithm
for its implementation and illustrative examples for Sylvester and Riccati
matrix differential equations are given.Comment: 14 pages; submitted to Math. Comp. Modellin
Salmonella enterica biofilm-mediated dispersal by nitric oxide donors in association with cellulose nanocrystal hydrogels
Protected by extracellular polymers, microbes within biofilms are significantly more resistant to disinfectants. Current research has been instrumental in identifying nitric oxide donors and hydrogels as potential disinfectant additives. Nitric oxide (NO) donors are considered a very promising molecule as biofilm dispersal agents and hydrogels have recently attracted a lot of interest due to their biocompatible properties and ability to form stable thin films. When the NO donor MAHMA NONOate was dissolved in phosphate saline buffer, it was able to reduce the biomass of well-established biofilms up to 15% for at least 24 h of contact time. Encapsulation of MAHMA NONOate and molsidomine within a hydrogel composed of cellulose nanocrystals (CNC) has shown a synergistic effect in dispersing well-established biofilms: after 2 h of exposure, moderate but significant dispersion was measured. After 6 h of exposure, the number of cells transitioning from the biofilm to the planktonic state was up to 0.6 log higher when compared with non-treated biofilms. To further explore the transport processes of NO donors within hydrogels, we measured the nitric oxide flux from gels, at 25°C for a composite of 0.1 µM MAHMA NONOate–CNC. Nitric oxide diffuses up to 500 µm from the hydrogel surface, with flux decreasing according to Fick’s law. 60% of NO was released from the hydrogel composite during the first 23 min. These data suggest that the combined treatments with nitric oxide donor and hydrogels may allow for new sustainable cleaning strategies
Global Characteristics of X-Ray Flashes and X-Ray-Rich GRBs Observed by HETE-2
We describe and discuss the global properties of 45 gamma-ray bursts (GRBs)
observed by HETE-2 during the first three years of its mission, focusing on the
properties of X-Ray Flashes (XRFs) and X-ray-rich GRBs (XRRs). We find that the
numbers of XRFs, XRRs, and GRBs are comparable. We find that the durations and
the sky distributions of XRFs and XRRs are similar to those of GRBs. We also
find that the spectral properties of XRFs and XRRs are similar to those of
GRBs, except that the values of the peak energy of the
burst spectrum in , the peak energy flux \Fp, and the energy
fluence of XRFs are much smaller -- and those of XRRs are smaller -- than
those of GRBs. Finally, we find that the distributions of all three kinds of
bursts form a continuum in the [(2-30 keV),(30-400) keV]-plane, the
[(2-400 keV), ]-plane, and the [(50-300 keV),
]-plane. These results provide strong evidence that all three
kinds of bursts arise from the same phenomenon.Comment: 33 pages, 15 figures, submitted to Ap
HETE Observations of the Gamma-Ray Burst GRB030329: Evidence for an Underlying Soft X-ray Component
An exceptionally intense gamma-ray burst, GRB030329, was detected and
localized by the instruments on board the High Energy Transient Explorer
satellite (HETE) at 11:37:14 UT on 29 March 2003. The burst consisted of two
\~10s pulses of roughly equal brightness and an X-ray tail lasting >100s. The
energy fluence in the 30-400 keV energy band was 1.08e-4 erg/cm2, making
GRB030329 one of the brightest GRBs ever detected. Communication of a 2 arcmin
error box 73 minutes after the burst allowed the rapid detection of a
counterpart in the optical, X-ray, radio and the ensuing discovery of a
supernova with most unusual characteristics. Analyses of the burst lightcurves
reveal the presence of a distinct, bright, soft X-ray component underlying the
main GRB: the 2-10 keV fluence of this component is ~7e-6 erg/cm2. The main
pulses of GRB030329 were preceded by two soft, faint, non-thermal bumps. We
present details of the HETE observations of GRB030329.Comment: 22 pages, 5 figures, to be published in ApJ 617, no. 2 (10 December
2004). Referee comments have been incorporated; results of improved spectral
analysis are include
HETE-2 Observation of two gamma-ray bursts at z > 3
GRB 020124 and GRB 030323 constitute half the sample of gamma-ray bursts with
a measured redshift greater than 3. This paper presents the temporal and
spectral properties of these two gamma-ray bursts detected and localized with
HETE-2. While they have nearly identical redshifts (z=3.20 for GRB 020124, and
z=3.37 for GRB 030323), these two GRBs span about an order of magnitude in
fluence, thus sampling distinct regions of the GRB luminosity function. The
properties of these two bursts are compared with those of the bulk of the GRB
population detected by HETE-2. We also discuss the energetics of GRB 020124 and
GRB 030323 and show that they are compatible with the Epeak - Eiso relation
discovered by Amati et al. (2002). Finally, we compute the maximum redshifts at
which these bursts could have been detected by HETE-2 and we address various
issues connected with the detection and localization of high-z GRBs.Comment: 19 pages, 4 figures, submitted to Ap
X-ray Flashes or soft Gamma-ray Bursts? The case of the likely distant XRF 040912
In this work, we present a multi-wavelength study of XRF 040912, aimed at
measuring its distance scale and the intrinsic burst properties. We performed a
detailed spectral and temporal analysis of both the prompt and the afterglow
emission and we estimated the distance scale of the likely host galaxy. We then
used the currently available sample of XRFs with known distance to discuss the
connection between XRFs and classical Gamma-ray Bursts (GRBs). We found that
the prompt emission properties unambiguously identify this burst as an XRF,
with an observed peak energy of E_p=17+/-13 keV and a burst fluence ratio
S(2-30keV)/S(30-400keV)>1. A non-fading optical source with R~24 mag and with
an apparently extended morphology is spatially consistent with the X-ray
afterglow, likely the host galaxy. XRF 040912 is a very dark burst since no
afterglow optical counterpart is detected down to R>25 mag (3 sigma limiting
magnitude) at 13.6 hours after the burst. The host galaxy spectrum detected
from 3800A to 10000A, shows a single emission line at 9552A. The lack of any
other strong emission lines blue-ward of the detected one and the absence of
the Ly alpha cut-off down to 3800A are consistent with the hypothesis of the
[OII] line at redshift z=1.563+/-0.001. The intrinsic spectral properties rank
this XRF among the soft GRBs in the E_peak-E_iso diagram. Similar results were
obtained for most XRFs at known redshift. Only XRF 060218 and XRF 020903
represent a good example of instrinsic XRF(i-XRF) and are possibly associated
with a different progenitor population. This scenario may calls for a new
definition of XRFs.Comment: 10 pages, 7 figures, accepted for publication in Astronomy &
Astrophysic
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