8,137 research outputs found
A catalogue of absorption-line systems in QSO spectra
We present a new catalog of absprption-line systems identified in the quasar
spectra. It contains data on 821 QSOs and 8558 absorption systems comprizing
16139 absorption lines with measured redshifts in the QSO spectra. The catalog
includes absorption-line systems consisting of lines of heavy elements, lines
of neutral hydrogen, Lyman limit systems, damped Ly\alpha absorption systems,
and broad absorption-line systems. The catalog is available in electronic form
at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/412/707 and at
www.ioffe.ru/astro/QC. Using the data of the present catalog we also discuss
redshift distributions of absorption-line systems.Comment: 3 pages with 1 postscript figur
Detection system ensures positive alarm activation in digital message loss
Lost Word Detection System /LOWDS/ provides special identification for each error detection message transmitted from receiver to transmitter. The message is identified as an original message or an n-times retransmitted message so the receiver can detect where a retransmission request was not fulfilled and activate an alarm
Geos 1 observations at Malvern, England
Satellite observation techniques and data processing methods at optical tracking station in Malvern, Englan
Extended OH(1720 MHz) Maser Emission from Supernova Remnants
Compact OH(1720 MHz) masers have proven to be excellent signposts for the
interaction of supernova remnants with adjacent molecular clouds. Less
appreciated has been the weak, extended OH(1720 MHz) emission which accompanies
strong compact maser sources. Recent single-dish and interferometric
observations reveal the majority of maser-emitting supernova remnants have
accompanying regions of extended maser emission. Enhanced OH abundance created
by the passing shock is observed both as maser emission and absorption against
the strong background of the remnant. Modeling the observed OH profiles gives
an estimate of the physical conditions in which weak, extended maser emission
arises. I will discuss how we can realize the utility of this extended maser
emission, particularly the potential to measure the strength of the post-shock
magnetic field via Zeeman splitting over these large-scales.Comment: 5 Pages, 2 Figures, To appear in IAU 242, Astrophysical Masers and
Their Environments, eds. J. Chapman & W. Baa
Space-times admitting a three-dimensional conformal group
Perfect fluid space-times admitting a three-dimensional Lie group of
conformal motions containing a two-dimensional Abelian Lie subgroup of
isometries are studied. Demanding that the conformal Killing vector be proper
(i.e., not homothetic nor Killing), all such space-times are classified
according to the structure of their corresponding three-dimensional conformal
Lie group and the nature of their corresponding orbits (that are assumed to be
non-null). Each metric is then explicitly displayed in coordinates adapted to
the symmetry vectors. Attention is then restricted to the diagonal case, and
exact perfect fluid solutions are obtained in both the cases in which the fluid
four-velocity is tangential or orthogonal to the conformal orbits, as well as
in the more general "tilting" case.Comment: Latex 34 page
A dynamical systems approach to the tilted Bianchi models of solvable type
We use a dynamical systems approach to analyse the tilting spatially
homogeneous Bianchi models of solvable type (e.g., types VI and VII)
with a perfect fluid and a linear barotropic -law equation of state. In
particular, we study the late-time behaviour of tilted Bianchi models, with an
emphasis on the existence of equilibrium points and their stability properties.
We briefly discuss the tilting Bianchi type V models and the late-time
asymptotic behaviour of irrotational Bianchi VII models. We prove the
important result that for non-inflationary Bianchi type VII models vacuum
plane-wave solutions are the only future attracting equilibrium points in the
Bianchi type VII invariant set. We then investigate the dynamics close to
the plane-wave solutions in more detail, and discover some new features that
arise in the dynamical behaviour of Bianchi cosmologies with the inclusion of
tilt. We point out that in a tiny open set of parameter space in the type IV
model (the loophole) there exists closed curves which act as attracting limit
cycles. More interestingly, in the Bianchi type VII models there is a
bifurcation in which a set of equilibrium points turn into closed orbits. There
is a region in which both sets of closed curves coexist, and it appears that
for the type VII models in this region the solution curves approach a
compact surface which is topologically a torus.Comment: 29 page
Ruptures and repairs of group therapy alliance. an untold story in psychotherapy research
Although previous studies investigated the characteristics of therapeutic alliance in group treatments, there is still a dearth of research on group alliance ruptures and repairs. The model by Safran and Muran was originally developed to address therapeutic alliance in individual therapies, and the usefulness of this approach to group intervention needs to be demonstrated. Alliance ruptures are possible at member to therapist, member to member, member to group levels. Moreover, repairs of ruptures in group are quite complex, i.e., because other group members have to process the rupture even if not directly involved. The aim of the current study is to review the empirical research on group alliance, and to examine whether the rupture repair model can be a suitable framework for clinical understanding and research of the complexity of therapeutic alliance in group treatments. We provide clinical vignettes and commentary to illustrate theoretical and research aspects of therapeutic alliance rupture and repair in groups. Our colleague Jeremy Safran made a substantial contribution to research on therapeutic alliance, and the current paper illustrates the enduring legacy of this work and its potential application to the group therapy context
Dispersal Dynamics in a Wind-Driven Benthic System
Bedload and water column traps were used with simultaneous wind and water velocity measurements to study postlarval macrofaunal dispersal dynamics in Manukau Harbour, New Zealand. A 12-fold range in mean wind condition resulted in large differences in water flow (12-fold), sediment flux (285-fold), and trap collection of total number of individuals (95-fold), number of the dominant infaunal organism (84-fold for the bivalve Macomona liliana), and number of species (4-fold). There were very strong, positive relationships among wind condition, water velocity, sediment flux, and postlarval dispersal, especially in the bedload. Local density in the ambient sediment was not a good predictor of dispersal. Results indicate that postlarval dispersal may influence benthic abundance pat- terns over a range of spatial scales
Entanglement without nonlocality
We consider the characterization of entanglement from the perspective of a
Heisenberg formalism. We derive an original two-party generalized separability
criteria, and from this describe a novel physical understanding of
entanglement. We find that entanglement may be considered as fundamentally a
local effect, and therefore as a separable computational resource from
nonlocality. We show how entanglement differs from correlation physically, and
explore the implications of this new conception of entanglement for the notion
of classicality. We find that this understanding of entanglement extends
naturally to multipartite cases.Comment: 9 pages. Expanded introduction and sections on physical entanglement
and localit
Toward Empirical Constraints on the Global Redshifted 21 cm Brightness Temperature During the Epoch of Reionization
Preliminary results are presented from a simple, single-antenna experiment
designed to measure the all-sky radio spectrum between 100 and 200 MHz. The
system used an internal comparison-switching scheme to reduce non-smooth
instrumental contaminants in the measured spectrum to 75 mK. From the
observations, we place an initial upper limit of 450 mK on the relative
brightness temperature of the redshifted 21 cm contribution to the spectrum due
to neutral hydrogen in the intergalactic medium (IGM) during the epoch of
reionization, assuming a rapid transition to a fully ionized IGM at a redshift
of 8. With refinement, this technique should be able to distinguish between
slow and fast reionization scenarios. To constrain the duration of reionization
to dz > 2, the systematic residuals in the measured spectrum must be reduced to
3 mK.Comment: Submitted to ApJ. 9 pages including 6 figure
- …