1,327 research outputs found
Die "ehezwecke" Eine soziologische se mora theologischer theorien
El punto de partida de los razonamientos referentes al -fin del matrimoniolo
constituye la exposición de la enseñanza tradicional sobre el matrimonio de
la Iglesia católica, la cual a pesar de ciertos aspectos poco claros, antepone
de un modo evidente la función reproductora como «finis operis». Estudiando
bien la enseñanza sobre el matrimonio de la Constitución pastoral «Gaudium
et spes» observamos que ésta está siendo interpretada por varios autores de un
modo incompleto, o totalmente en contra de la enseñanza tradicional sobre el matrimonio.
Puesto que de hecho la tradicional ordenación sucesiva de los .fines del
matrimonio» ha sido trastocada. Sin embargo bajo el punto de vista de una sociología
sistemática, hemos de sostener una prioridad jerárquica de la función reproductora
como fin del matrimonio. El amor matrimonial, no puede ser señalado como
.causa del matrimonio», ya que el amor como momento ineludible en la estructura
del matrimonio debe anteponerse si lo que tenemos en cuenta es la función.
Además el amor, que de un modo general puede ser definido como deseo
voluntario en formar una unidad (social), corresponde esencialmente a cada una
de las unidades sociales, por lo que bajo ningún motivo puede ser señalado
como «differentia specifica» del matrimonio.
Estos razonamientos de una SOCiología crítica, que se reconoce como ciencia
moral, pueden llevarnos a una interpretación que aclare la enseñanza tradicional
sobre el matrimonio de la Iglesia, mientras que la enseñanza modernista sobre
el matrimonio, bajo esta perspectiva ha de ser considerada como algo que fracciona
en partes, como carente de sistema, y dañosa por sus previsibles consecuencias
en la comprensión cristiana del matrimonio
Tectono-metamorphic evolution of the Wadi Hafafit Culmination (central Eastern Desert, Egypt). Implication for Neoproterozoic core complex exhumation in NE Africa
The Neoproterozoic rock assemblages in the Wadi Hafafit Culmination (WHC) can be subdivided into two main units which are separated by the Nugrus Thrust. The structurally higher Nugrus unit is mainly composed of low grade micaschists, metavolcanic, serpentinites, and metagabbros. The overthrusted Hafafit unit forms the Hafafit domes and is composed of ortho- and para-gneisses associated with amphibolite and ultramafic rocks. Mineral chemistry and thermobarometry indicate that the WHC was affected by two main metamorphic phases. The first metamorphic phase (M1), observed in the micaschists of the Nugrus unit, is characterized by greenschist- facies conditions. Garnet-biotite and garnet-muscovite geothermometry, as well as temperatures calculated by means of the TWEEQU program yield temperatures of 400°–550°C, whereas the white mica geobarometer reveals pressure of 3.7-4.9 kbar for this metamorphic phase (M1). The second metamorphic phase (M2), observed in gneisses and amphibolites of the Hafafit unit, is characterized by amphibolite-facies conditions. Garnet-biotite, garnet-amphibole and amphibole-plagioclase geothermometry yield temperatures of 600°–750°C, whereas the garnet-hornblende-plagioclase-quartz geobarometer indicates pressures of 6-8 kbar for the second metamorphic phase (M2). Sm-Nd and Rb-Sr whole rock-mineral isochron ages around 590 Ma for gneisses and amphibolites probably represent cooling from the metamorphic thermal peak which was attained around 600 Ma or slightly earlier. A 3-stage geologic evolution model is proposed for the tectonic evolution of the WHC. The first stage started earlier than 680 Ma ago with rifting and ocean floor spreading at a time which is as yet unspecified. It was followed by a second stage of subduction and emplacement of subduction-related granitoids around 620-640 Ma. At this time, the Hafafit region has become an active margin with the production of large amounts of calc-alkaline subduction-related volcanic and plutonic sequences. Subduction was terminated by collision and NW-ward Nugrus Nappe thrusting under greenschist-facies conditions (M1) around 620-640 Ma. At this stage, rocks of Hafafit unit were subjected to intense deformation and metamorphism in amphibolite facies (M2). Next came the third stage of late-orogenic extension and crustal thinning that was controlled by the Najd transform faults (620-580 my) and that resulted in exhumation of the Hafafit domes through a combination of transpression and lateral extrusion
Tethered subsatellite study
The results are presented of studies performed relating to the feasibility of deploying a subsatellite from the shuttle by means of a tether. The dynamics, the control laws, the aerodynamics, the heating, and some communication considerations of the tethered subsatellite system are considered. Nothing was found that prohibits the use of a subsatellite joined to the shuttle by a long (100 km) tether. More detailed studies directed at specific applications are recommended
On the Effect of Constraint Enforcement on the Quality of Numerical Solutions in General Relativity
In Brodbeck et al 1999 it has been shown that the linearised time evolution
equations of general relativity can be extended to a system whose solutions
asymptotically approach solutions of the constraints. In this paper we extend
the non-linear equations in similar ways and investigate the effect of various
possibilities by numerical means. Although we were not able to make the
constraint submanifold an attractor for all solutions of the extended system,
we were able to significantly reduce the growth of the numerical violation of
the constraints. Contrary to our expectations this improvement did not imply a
numerical solution closer to the exact solution, and therefore did not improve
the quality of the numerical solution.Comment: 14 pages, 9 figures, accepted for publication in Phys. Rev.
Bondian frames to couple matter with radiation
A study is presented for the non linear evolution of a self gravitating
distribution of matter coupled to a massless scalar field. The characteristic
formulation for numerical relativity is used to follow the evolution by a
sequence of light cones open to the future. Bondian frames are used to endow
physical meaning to the matter variables and to the massless scalar field.
Asymptotic approaches to the origin and to infinity are achieved; at the
boundary surface interior and exterior solutions are matched guaranteeing the
Darmois--Lichnerowicz conditions. To show how the scheme works some numerical
models are discussed. We exemplify evolving scalar waves on the following fixed
backgrounds: A) an atmosphere between the boundary surface of an incompressible
mixtured fluid and infinity; B) a polytropic distribution matched to a
Schwarzschild exterior; C) a Schwarzschild- Schwarzschild spacetime. The
conservation of energy, the Newman--Penrose constant preservation and other
expected features are observed.Comment: 20 pages, 6 figures; to appear in General Relativity and Gravitatio
Numerical Evolution of axisymmetric vacuum spacetimes: a code based on the Galerkin method
We present the first numerical code based on the Galerkin and Collocation
methods to integrate the field equations of the Bondi problem. The Galerkin
method like all spectral methods provide high accuracy with moderate
computational effort. Several numerical tests were performed to verify the
issues of convergence, stability and accuracy with promising results. This code
opens up several possibilities of applications in more general scenarios for
studying the evolution of spacetimes with gravitational waves.Comment: 11 pages, 6 figures. To appear in Classical and Quantum Gravit
Opposing Activities of Notch and Wnt Signaling Regulate Intestinal Stem Cells and Gut Homeostasis
SummaryProper organ homeostasis requires tight control of adult stem cells and differentiation through the integration of multiple inputs. In the mouse small intestine, Notch and Wnt signaling are required both for stem cell maintenance and for a proper balance of differentiation between secretory and absorptive cell lineages. In the absence of Notch signaling, stem cells preferentially generate secretory cells at the expense of absorptive cells. Here, we use function-blocking antibodies against Notch receptors to demonstrate that Notch blockade perturbs intestinal stem cell function by causing a derepression of the Wnt signaling pathway, leading to misexpression of prosecretory genes. Importantly, attenuation of the Wnt pathway rescued the phenotype associated with Notch blockade. These studies bring to light a negative regulatory mechanism that maintains stem cell activity and balanced differentiation, and we propose that the interaction between Wnt and Notch signaling described here represents a common theme in adult stem cell biology
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ATLAS Tracking Event Data Model
In this report the event data model (EDM) relevant for tracking in the ATLAS experiment is presented. The core component of the tracking EDM is a common track object which is suited to describe tracks in the innermost tracking sub-detectors and in the muon detectors in offline as well as online reconstruction. The design of the EDM was driven by a demand for modularity and extensibility while taking into account the different requirements of the clients. The structure of the track object and the representation of the tracking-relevant information are described in detail
Tips for implementing multigrid methods on domains containing holes
As part of our development of a computer code to perform 3D `constrained
evolution' of Einstein's equations in 3+1 form, we discuss issues regarding the
efficient solution of elliptic equations on domains containing holes (i.e.,
excised regions), via the multigrid method. We consider as a test case the
Poisson equation with a nonlinear term added, as a means of illustrating the
principles involved, and move to a "real world" 3-dimensional problem which is
the solution of the conformally flat Hamiltonian constraint with Dirichlet and
Robin boundary conditions. Using our vertex-centered multigrid code, we
demonstrate globally second-order-accurate solutions of elliptic equations over
domains containing holes, in two and three spatial dimensions. Keys to the
success of this method are the choice of the restriction operator near the
holes and definition of the location of the inner boundary. In some cases (e.g.
two holes in two dimensions), more and more smoothing may be required as the
mesh spacing decreases to zero; however for the resolutions currently of
interest to many numerical relativists, it is feasible to maintain second order
convergence by concentrating smoothing (spatially) where it is needed most.
This paper, and our publicly available source code, are intended to serve as
semi-pedagogical guides for those who may wish to implement similar schemes.Comment: 18 pages, 11 figures, LaTeX. Added clarifications and references re.
scope of paper, mathematical foundations, relevance of work. Accepted for
publication in Classical & Quantum Gravit
Advantages of modified ADM formulation: constraint propagation analysis of Baumgarte-Shapiro-Shibata-Nakamura system
Several numerical relativity groups are using a modified ADM formulation for
their simulations, which was developed by Nakamura et al (and widely cited as
Baumgarte-Shapiro-Shibata-Nakamura system). This so-called BSSN formulation is
shown to be more stable than the standard ADM formulation in many cases, and
there have been many attempts to explain why this re-formulation has such an
advantage. We try to explain the background mechanism of the BSSN equations by
using eigenvalue analysis of constraint propagation equations. This analysis
has been applied and has succeeded in explaining other systems in our series of
works. We derive the full set of the constraint propagation equations, and
study it in the flat background space-time. We carefully examine how the
replacements and adjustments in the equations change the propagation structure
of the constraints, i.e. whether violation of constraints (if it exists) will
decay or propagate away. We conclude that the better stability of the BSSN
system is obtained by their adjustments in the equations, and that the
combination of the adjustments is in a good balance, i.e. a lack of their
adjustments might fail to obtain the present stability. We further propose
other adjustments to the equations, which may offer more stable features than
the current BSSN equations.Comment: 10 pages, RevTeX4, added related discussion to gr-qc/0209106, the
version to appear in Phys. Rev.
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