313 research outputs found
Evaluating corporate performance:a critique of economic value added
There has been a revival of interest in economic techniques to measure the value of a firm through the use of economic value added as a technique for measuring such value to shareholders. This technique, based upon the concept of economic value equating to total value, is founded upon the assumptions of classical liberal economic theory. Such techniques have been subject to criticism both from the point of view of the level of adjustment to published accounts needed to make the technique work and from the point of view of the validity of such techniques in actually measuring value in a meaningful context. This paper critiques economic value added techniques as a means of calculating changes in shareholder value, contrasting such techniques with more traditional techniques of measuring value added. It uses the company Severn Trent plc as an actual example in order to evaluate and contrast the techniques in action. The paper demonstrates discrepancies between the calculated results from using economic value added analysis and those reported using conventional accounting measures. It considers the merits of the respective techniques in explaining shareholder and managerial behaviour and the problems with using such techniques in considering the wider stakeholder concept of value. It concludes that this economic value added technique has merits when compared with traditional accounting measures of performance but that it does not provide the universal panacea claimed by its proponents
Discovery of a nuclear gas bar feeding the active nucleus in Circinus
We report the discovery of gas inflow motions towards the active nucleus of
the Circinus galaxy caused by the non-axisymmetric potential of a nuclear gas
bar. Evidence for dust associated with the bar comes from the HST/NICMOS H-K
color map, whereas the streaming motions along the gas bar are seen in the
velocity field of the H2 S(1)(1-0) emission line. The gas bar is about 100 pc
long with a visual extinction in excess of 10 mag. Indication for the gaseous
nature of this bar comes from the lack of a stellar counterpart even in the K
band where the extinction is greatly reduced.
We also use the NICMOS emission line images (Pa-alpha, [SiVI], and [FeII]) to
study the innermost region of the ionization cones and the nuclear star forming
activity. We discuss the possible relationship of these components with the
gaseous bar.Comment: 14 pages, 7 figures (3 color plates), accepted for publication in Ap
Herschel-PACS Observations of Far-IR CO Line Emission in NGC 1068: Highly Excited Molecular Gas in the Circumnuclear Disk
We report the detection of far-IR CO rotational emission from the
prototypical Seyfert 2 galaxy NGC 1068. Using Herschel-PACS, we have detected
11 transitions in the J_upper=14-30 (E_upper/k_B = 580-2565 K) range, all of
which are consistent with arising from within the central 10" (700 pc). The
detected transitions are modeled as arising from 2 different components: a
moderate excitation (ME) component close to the galaxy systemic velocity, and a
high excitation (HE) component that is blueshifted by ~80 km s^{-1}. We employ
a large velocity gradient (LVG) model and derive n_H2~10^{5.6} cm^{-3},
T_kin~170 K, and M_H2~10^{6.7} M_sun for the ME component, and n_H2~10^{6.4}
cm^{-3}, T_kin~570 K, and M_H2~10^{5.6} M_sun for the HE component, although
for both components the uncertainties in the density and mass are plus/minus
(0.6-0.9) dex. We compare the CO line profiles with those of other molecular
tracers observed at higher spatial and spectral resolution, and find that the
ME transitions are consistent with these lines arising in the ~200 pc diameter
ring of material traced by H_2 1-0 S(1) observations. The blueshift of the HE
lines may also be consistent with the bluest regions of this H_2 ring, but a
better kinematic match is found with a clump of infalling gas ~40 pc north of
the AGN. We discuss the prospects of placing the HE component near the AGN, and
conclude that while the moderate thermal pressure precludes an association with
the ~1 pc radius H_2O maser disk, the HE component could potentially be located
only a few parsecs more distant from the AGN, and might then provide the
N_H~10^{25} cm^{-2} column obscuring the nuclear hard X-rays. Finally, we also
report sensitive upper limits extending up to J_upper=50, which place
constraints on a previous model prediction for the CO emission from the X-ray
obscuring torus. [Abridged]Comment: 20 pages, 10 figures. Accepted for publication in Ap
The SAMI Galaxy Survey: Global stellar populations on the size-mass plane
We present an analysis of the global stellar populations of galaxies in the
SAMI Galaxy Survey. Our sample consists of 1319 galaxies spanning four orders
of magnitude in stellar mass and includes all morphologies and environments. We
derive luminosity-weighted, single stellar population equivalent stellar ages,
metallicities and alpha enhancements from spectra integrated within one
effective radius apertures. Variations in galaxy size explain the majority of
the scatter in the age--mass and metallicity--mass relations. Stellar
populations vary systematically in the plane of galaxy size and stellar mass,
such that galaxies with high stellar surface mass density are older, more
metal-rich and alpha-enhanced than less dense galaxies. Galaxies with high
surface mass densities have a very narrow range of metallicities, however, at
fixed mass, the spread in metallicity increases substantially with increasing
galaxy size (decreasing density). We identify residual correlations with
morphology and environment. At fixed mass and size, galaxies with late-type
morphologies, small bulges and low Sersic n are younger than early-type, high
n, high bulge-to-total galaxies. Age and metallicity both show small residual
correlations with environment; at fixed mass and size, galaxies in denser
environments or more massive halos are older and somewhat more metal rich than
those in less dense environments. We connect these trends to evolutionary
tracks within the size--mass plane.Comment: 25 pages, 18 figures, MNRAS in press Corrected typo in author lis
The magnetic field toward the young planetary nebula K~3-35
K 3-35 is a planetary nebula (PN) where H2O maser emission has been detected,
suggesting that it departed from the proto-PNe phase only some decades ago.
Interferometric VLA observations of the OH 18 cm transitions in K~3-35 are
presented.OH maser emission is detected in all four ground state lines (1612,
1665, 1667, and 1720 MHz). All the masers appear blueshifted with respect to
the systemic velocity of the nebula and they have different spatial and
kinematic distributions.The OH 1665 and 1720 MHz masers appear spatially
coincident with the core of the nebula, while the OH 1612 and 1667 MHz ones
exhibit a more extended distribution. We suggest that the 1665 and 1720 masers
arise from a region close to the central star, possibly in a torus, while the
1612 and 1667 lines originate mainly from the extended northern lobe of the
outflow. It is worth noting that the location and velocity of the OH 1720 MHz
maser emission are very similar to those of the H2O masers (coinciding within
0.1" and ~2 km/s, respectively). We suggest that the pumping mechanism in the
H2O masers could be produced by the same shock that is exciting the OH 1720 MHz
transition. A high degree of circular polarization (>50%) was found to be
present in some features of the 1612, 1665, and 1720 MHz emission.For the 1665
MHz transition at ~ +18 km/s the emission with left and right circular
polarizations (LCP and RCP) coincide spatially within a region of ~0.03" in
diameter.Assuming that these RCP and LCP 1665 features come from a Zeeman pair,
we estimate a magnetic field of ~0.9 mG within 150 AU from the 1.3 cm continuum
peak. This value is in agreement with a solar-type magnetic field associated
with evolved stars.Comment: 6 pages, 2 tables, 4 figures, ApJ accepte
The Test Re-Test Reliability of A Novel Single Leg Hop Test (T-Drill Hop Test)
# Background
Functional training and testing are an important part of a comprehensive rehabilitation program stressing the neuromuscular system in ways that simulate athletic performance to help determine criteria for return to sport. There are numerous single leg hop tests that have been used for these purposes, however, the validity and clinical relevance has been questioned. Many of the functional performance tests assess only the sagittal plane or forward direction and may only partially assess a person’s athletic abilities. There is a need for reliable and valid functional tests to assess in a multi-directional manner.
# Purpose/Hypothesis
The purpose of this study is to determine the test re-test reliability of a novel multi-directional timed single leg hop test (T-Drill Hop Test) for use in rehabilitation and performance assessments.
# Study Design
Cross-sectional reliability study.
# Methods
Fifty healthy recreationally active college age subjects, (23 males and 27 females) between the ages of 18 and 35, (mean age 23.48 with SD 3.82) consented to perform the test. The subjects hopped along a 10ft. x 10ft. “T” shaped course. Subjects performed two timed maximum effort trials of the T-Drill Hop Test on each leg with an interval of 3-7 days between the two testing days. Intraclass Correlation Coefficients (ICC) were calculated to determine intersession reliability.
# Results
The inter-rater reliability (ICC’s) for the entire group of 50 subjects ranged between .98 and 1.00 suggesting excellent reliability. The bilateral comparison, utilizing paired t-tests, of the T-Drill Hop Test demonstrated no significant differences between the time scores for the dominant and non-dominant legs for either males or females (p>.05).
# Conclusion
This study demonstrates the T-Drill Hop Test has excellent test re-test reliability. These results are important prior to validation and utilization as a clinical functional performance test.
# Levels of Evidence
Level
The Star-Forming Torus and Stellar Dynamical Black Hole Mass in the Seyfert 1 Nucleus of NGC3227
We report R~4300 VLT SINFONI adaptive optics integral field K-band
spectroscopy of the nucleus of the Seyfert 1 galaxy NGC3227 at a spatial
resolution of 0.085" (7pc). We present the morphologies and kinematics of
emission lines and absorption features, and give the first derivation of a
black hole mass in a Seyfert 1 nucleus from spatially resolved stellar
dynamics. We show that the gas in the nucleus has a mean column density of
order 10^{24}-10^{25}cm^{-2} and that it is geometrically thick, in agreement
with the standard `molecular torus' scenario. We discuss which heating
processes may be responsible for maintaining the vertical height of the torus.
We have also resolved the nuclear stellar distribution, and find that within a
few parsecs of the AGN there has been an intense starburst, the most recent
episode of which began ~40Myr ago but has now ceased. The current luminosity of
stars within 30pc of the AGN, ~3x10^9L_sun, is comparable to that of the AGN.
Based on a comparison of the respective size scales, we argue that the star
formation has been occuring in the obscuring torus. Finally, we present the
first derivation of a black hole mass in a Seyfert 1 nucleus from stellar
dynamics which marginally spatially resolve the black hole's sphere of
influence. We apply Schwarzschild orbit superposition models to our full
2-dimensional data and derive the mass of the black hole, paying careful
attention to the input parameters which are often uncertain: the contribution
of the large scale bulge and its mass-to-light ratio; the recent star formation
in the nucleus and its mass-to-light ratio; the contribution of the gas mass to
the potential; and the inclination. Our models yield a 1sigma range for the
black hole mass of M_{BH} = 7x10^6-2x10^7M_sun.Comment: Accepted by ApJ, 42 pages with 20 figure
Galaxy and Mass Assembly (GAMA): active galactic nuclei in pairs of galaxies
There exist conflicting observations on whether or not the environment of broad- and narrowline active galatic nuclei (AGN) differ and this consequently questions the validity of the AGN unification model. The high spectroscopic completeness of the Galaxy and Mass Assembly (GAMA) survey makes it ideal for a comprehensive analysis of the close environment of galaxies. To exploit this, and conduct a comparative analysis of the environment of broad- and narrow-line AGN within GAMA, we use a double-Gaussian emission line fitting method to model the more complex line profiles associated with broad-line AGN. We select 209 type 1 (i.e. unobscured), 464 type 1.5–1.9 (partially obscured), and 281 type 2 (obscured) AGN within the GAMA II data base. Comparing the fractions of these with neighbouring galaxies out to a pair separation of 350 kpc h−1 and Δz < 0.012 shows no difference between AGN of different type, except at separations less than 20 kpc h−1 where our observations suggest an excess of type 2 AGN in close pairs. We analyse the properties of the galaxies neighbouring our AGN and find no significant differences in colour or the star formation activity of these galaxies. Further to this, we find that Σ5 is also consistent between broad- and narrow-line AGN. We conclude that the observations presented here are consistent with AGN unification
Unilateral versus coordinated effects:comparing the impact on consumer welfare of alternative merger outcomes
The nature of tacitly collusive behaviour often makes coordination unstable, and this may result in periods of breakdown, during which consumers benet from reduced prices. This is allowed for by adding demand uncertainty to the Compte et al. (2002) model of tacit collusion amongst asymmetric rms. Breakdowns occur when a rm cannot exclude the possibility of a deviation by a rival. It is then possible that an outcome with collusive behaviour, subject to long/frequent break downs, can improve consumer welfare compared to an alternative with sustained unilateral conduct. This is illustrated by re-examining the Nestle/Perrier merger analyzed by Compte et al., but now also taking into account the potential for welfare losses arising from unilateral behaviour
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