34,280 research outputs found
One way forward: non-traditional accounting disclosures in the 21st century
Recent empirical studies (Deegan and Rankin, 1999; Deegan et al., 2000) have indicated that although
many corporations have begun to respond to perceived demand for environmental disclosures in
published accounts, their perspective of organisational legitimacy is a narrow view, in which information
is targeted towards specific stakeholders and not to the general public.
This paper considers a range of models (variously called guidelines, standards and charters) which
have been put forward by different organisations to aid the development of social and environmental
disclosures. In all cases verification and attestation are part of the proposed regimen.
The question which the papers attempts to answer is whether any one of the models would be capable
of rapid adoption as part of an expanded GAAP, should the professional accounting bodies think that
this is desirable. The outcome of our deliberations is cautious support for the use of EMAS and ISO
14000 as the basis for a modified GAAP plus the further development of the GRI 2000 guidelines into a
set of standards covering both social and environmental reporting
WHAM Observations of H-Alpha, [S II], and [N II] toward the Orion and Perseus Arms: Probing the Physical Conditions of the Warm Ionized Medium
A large portion of the Galaxy (l = 123 deg to 164 deg, b = -6 deg to -35
deg), which samples regions of the Local (Orion) spiral arm and the more
distant Perseus arm, has been mapped with the Wisconsin H-Alpha Mapper (WHAM)
in the H-Alpha, [S II] 6716, and [N II] 6583 lines. Several trends noticed in
emission-line investigations of diffuse gas in other galaxies are confirmed in
the Milky Way and extended to much fainter emission. We find that the [S
II]/H-Alpha and [N II]/H-Alpha ratios increase as absolute H-Alpha intensities
decrease. For the more distant Perseus arm emission, the increase in these
ratios is a strong function of Galactic latitude and thus, of height above the
Galactic plane. The [S II]/[N II] ratio is relatively independent of H-Alpha
intensity. Scatter in this ratio appears to be physically significant, and maps
of it suggest regions with similar ratios are spatially correlated. The Perseus
arm [S II]/[N II] ratio is systematically lower than Local emission by 10%-20%.
With [S II]/[N II] fairly constant over a large range of H-Alpha intensities,
the increase of [S II]/H-Alpha and [N II]/H-Alpha with |z| seems to reflect an
increase in temperature. Such an interpretation allows us to estimate the
temperature and ionization conditions in our large sample of observations. We
find that WIM temperatures range from 6,000 K to 9,000 K with temperature
increasing from bright to faint H-Alpha emission (low to high [S II]/H-Alpha
and [N II]/H-Alpha) respectively. Changes in [S II]/[N II] appear to reflect
changes in the local ionization conditions (e.g. the S+/S++ ratio). We also
measure the electron scale height in the Perseus arm to be 1.0+/-0.1 kpc,
confirming earlier, less accurate determinations.Comment: 28 pages, 10 figures. Figures 2 and 3 are full color--GIFs provided
here, original PS figures at link below. Accepted for publication in ApJ.
More information about the WHAM project can be found at
http://www.astro.wisc.edu/wham/ . REVISION: Figure 6, bottom panel now
contains the proper points. No other changes have been mad
Observations of the Extended Distribution of Ionized Hydrogen in the Plane of M31
We have used the Wisconsin H-Alpha Mapper (WHAM) to observe the spatially
extended distribution of ionized hydrogen in M31 beyond the stellar disk. We
obtained five sets of observations, centered near the photometric major axis of
M31, that extend from the center of the galaxy to just off the edge of the
southwestern HI disk. Beyond the bright stellar disk, but within the HI disk,
weak H-alpha is detected with an intensity I(H-alpha) = 0.05 (+0.01 / -0.02)
Rayleighs. Since M31 is inclined 77 degrees with respect to the line of sight,
this implies that the ambient intergalactic ionizing flux onto each side of M31
is Phi_0 <= 1.6 x 10^4 photons cm^-2 s^-1. Just beyond the outer boundary of
the HI disk we find no significant detection of H-alpha and place an upper
limit I(H-alpha) <= 0.019 Rayleighs.Comment: To appear in ApJ Letters; 12 pages, 4 figure
WHAM Observations of H-alpha from High-Velocity Clouds: Are They Galactic or Extragalactic?
It has been suggested that high velocity clouds may be distributed throughout
the Local Group and are therefore not in general associated with the Milky Way
galaxy. With the aim of testing this hypothesis, we have made observations in
the H-alpha line of high velocity clouds selected as the most likely candidates
for being at larger than average distances. We have found H-alpha emission from
4 out of 5 of the observed clouds, suggesting that the clouds under study are
being illuminated by a Lyman continuum flux greater than that of the
metagalactic ionizing radiation. Therefore, it appears likely that these clouds
are in the Galactic halo and not distributed throughout the Local Group.Comment: 12 pages, 5 eps figures, accepted for publication in ApJ Letter
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