12,919 research outputs found
AGN Feedback models: Correlations with star formation and observational implications of time evolution
We examine the correlation between the star formation rate (SFR) and black
hole accretion rate (BHAR) across a suite of different AGN feedback models,
using the time evolution of a merger simulation. By considering three different
stages of evolution, and a distinction between the nuclear and outer regions of
star formation, we consider 63 different cases. Despite many of the feedback
models fitting the M-\sigma\ relationship well, there are often distinct
differences in the SFR-BHAR correlations, with close to linear trends only
being present after the merger. Some of the models also show evolution in the
SFR-BHAR parameter space that is at times directly across the long-term
averaged SFR-BHAR correlation. This suggests that the observational SFR-BHAR
correlation found for ensembles of galaxies is an approximate statistical
trend, as suggested by Hickox et al. Decomposing the SFR into nuclear and outer
components also highlights notable differences between models and there is only
modest agreement with observational studies examining this in Seyfert galaxies.
For the fraction of the black hole mass growth from the merger event relative
to the final black hole mass, we find as much as a factor of three variation
among models. This also translates into a similar variation in the
post-starburst black hole mass growth. Overall, we find that while qualitative
features are often similar amongst models, precise quantitative analysis shows
there can be quite distinct differences.Comment: Accepted to MNRAS. Comments welcom
Discrimination and Quantification of Glomerular Receptor Subtypes for Atrial Natriuretic Factor (Anf)
Binding sites for atrial natriuretic factor (ANF) were determined on isolated rat glomeruli as well as on glomerular membranes. To define optimal conditions, binding of ANF was investigated varying incubation time, temperature and protein concentration. Binding conditions were found to be best at 4°C for 5 hours with 15 Όg of glomerular protein. Saturation and affinity cross-linking experiments confirmed the presence of two distinct receptor subtypes - the B-receptor (130 kDa) and the C-receptor (65 kDa). Quantitative differentiation of both ANF binding sites was achieved by competitive displacement with two different unlabeled ANF ligands: a) rANF(99-126) (homologous displacement), b) des(18-22)rANF(4-23)NH2(heterologous displacement). Intact glomeruli and glomerular membranes did not differ significantly in receptor density for the B-receptor (71 ± 37 vs. 94 ± 53 fmol/mg protein) or the C-receptor (976 ± 282 vs. 966 ± 167 fmol/mg protein) or in affinity constants for the B-receptor (43 ± 36 vs. 52 ± 44 pM) or the C-receptor (876 ± 377 vs. 307 ± 36 pM). Glomerular membranes compared to glomeruli showed less nonspecific binding and less intra-assay variation of measuring points done in triplicates. This method of selective displacement should allow to study the influence of various physiological and pathophysiological conditions on the binding properties of B-and C-receptors for ANF
International Outsourcing and the Skill Structure of Labour Demand in the United Kingdom
This paper investigates empirically the link between international outsourcing and the skill structure of labour demand in the United Kingdom. It is the first detailed study of this issue for the UK. Outsourcing is calculated using import-use matrices of input-output tables for manufacturing industries for the period 1982 to 1996. Estimating a system of variable factor demands, our main results show that international outsourcing has had a strong negative impact on the demand for unskilled labour. Hence, international outsourcing is an important component in explanations of the changing skill structure of manufacturing industries in the United Kingdom.Outsourcing; Fragmentation; Trade; Wages; Skill-biased technological change
Human interleukin-1 receptor antagonist is expressed in liver
AbstractUsing PCR and Northern blot analysis, an IL-1 receptor antagonist specific transcript was amplified from HepG2- and liver mRNA, cDNA clones coding for IL-1 receptor antagonist were isolated from a liver cDNA library and sequence comparison revealed complete identity with the secreted, monocytic form of IL-1 receptor antagonist
Persistence of Tripartite Nonlocality for Non-inertial Observers
We consider the behaviour of bipartite and tripartite non-locality between
fermionic entangled states shared by observers, one of whom uniformly
accelerates. We find that while fermionic entanglement persists for arbitrarily
large acceleration, the Bell/CHSH inequalities cannot be violated for
sufficiently large but finite acceleration. However the Svetlichny inequality,
which is a measure of genuine tripartite non-locality, can be violated for any
finite value of the acceleration.Comment: 4 pages, pdflatex, 2 figure
AIRNET: A real-time comunications network for aircraft
A real-time local area network was developed for use on aircraft and space vehicles. It uses token ring technology to provide high throughput, low latency, and high reliability. The system was implemented on PCs and PC/ATs operating on PCbus, and on Intel 8086/186/286/386s operating on Multibus. A standard IEEE 802.2 logical link control interface was provided to (optional) upper layer software; this permits the controls designer to utilize standard communications protocols (e.g., ISO, TCP/IP) if time permits, or to utilize a very fast link level protocol directly if speed is critical. Both unacknowledged datagram and reliable virtual circuit services are supported. A station operating an 8 MHz Intel 286 as a host can generate a sustained load of 1.8 megabits per second per station, and a 100-byte message can be delivered from the transmitter's user memory to the receiver's user memory, including all operating system and network overhead, in under 4 milliseconds
Finding Optimal-Path Maps for Path Planning Across Weighted Regions
This paper appeared in the International Journal of Robotics Research, 19, 2 (February 2000), pp. 83-95, with
elaborating additions from [Rowe and Alexander, 1997]. The equations were redone for greatly improved clarity in
2008.Optimal-path maps tell robots or people the best way to reach a goal point from anywhere in a known terrain area,
eliminating most of the need to plan during travel. We address the construction of optimal-path maps for twodimensional
polygonal weighted-region terrain, terrain partitioned into polygonal areas such that the cost per unit
distance traveled is homogeneous and isotropic within each polygon. This is useful for overland route planning across
varied ground surfaces and vegetation. We propose a new algorithm that recursively partitions terrain into regions of
similar optimal-path behavior, and defines corresponding "path subspaces" for these regions. This process constructs
a piecewise-smooth function of terrain position whose gradient direction is everywhere the optimal-path direction,
permitting quick finding of optimal paths. Our algorithm is more complicated than the current path-caching and
wavefront-propagation algorithms, but gives more accurate maps requiring less space to represent. Experiments with
an implementation confirm the practicality of our algorithm.This work was supported in part by the U.S. Army Combat Developments Experimentation Center under MIPR ATEC 88-86. This work was also prepared in part in conjunction with research conducted for the Naval Air Systems Command and funded by the Naval Postgraduate School.supported in part by the U.S. Army Combat Developments Experimentation Center under MIPR ATEC 88-86. This work was also prepared in part in conjunction with research conducted for the Naval Air Systems Command and funded by the Naval Postgraduate School.Approved for public release; distribution is unlimited
High Quality Ultrathin Bi2Se3 Films on CaF2 and CaF2/Si by Molecular Beam Epitaxy with a Radio Frequency Cracker Cell
Here we report a method to fabricate high quality Bi2Se3 thin films using
molecular beam epitaxy with a radio frequency cracker cell as an atomic
selenium source. With rates close to exact stoichiometry, optimal
layer-by-layer growth of high quality Bi2Se3 thin films with smooth surfaces,
has been achieved on CaF2(111) substrates and Si(111) substrates with a thin
CaF2 buffer layer(CaF2/Si). Transport measurements show a characteristic weak
antilocalization mangnetoresistance, with emergence of weak localization in the
ultrathin film limit. Quantum Oscillations attributed to the topological
surface states have been observed, including in films on CaF2/Si
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