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Dealing with propositional ambiguity in business process improvement
If it is true that people express their views about organisational issues in ambiguous terms then one needs to address this ambiguity instead of the âproblemsâ to find an appropriate methodological approach to resolving or dissolving problem situations in the organisation. This paper highlights and discusses those issues, which therefore relate to ambiguityin relation to decision making tasks within organisations, and the related Soft Systems Methodology / Systems Thinking school of thought, which traditionally constrains such ambiguities. A model of these issues is presented in terms of the Business Process Improvement (BPI) task to highlight these interdependencies
Probing the Interstellar Medium using HI absorption and emission towards the W3 HII region
HI spectra towards the W3 HII complex are presented and used to probe the
Galactic structure and interstellar medium conditions between us and this
region. The overall shape of the spectra is consistent with the predictions of
the Two-Arm Spiral Shock model wherein the gas found in the -40 km/s to -50
km/s range has been accelerated by some 20 km/s from its rotation curve
velocity. Spin temperatures of ~100 K are derived for the Local Arm gas, lower
than found in a previous, similar study towards DR 7. For the interarm region,
values on the order of 300 K are found, implying a negligible filling factor
for the Cold Neutral Medium (<< 1%). Some of the absorbing gas at velocities
near -40 km/s is confirmed to be associated with the HII regions.Comment: 23 pages, 6 figures, accepted for publication in the Astronomical
Journa
Molecular gas heating in Arp 299
Understanding the heating and cooling mechanisms in nearby (Ultra) luminous
infrared galaxies can give us insight into the driving mechanisms in their more
distant counterparts. Molecular emission lines play a crucial role in cooling
excited gas, and recently, with Herschel Space Observatory we have been able to
observe the rich molecular spectrum. CO is the most abundant and one of the
brightest molecules in the Herschel wavelength range. CO transitions are
observed with Herschel, and together, these lines trace the excitation of CO.
We study Arp 299, a colliding galaxy group, with one component harboring an AGN
and two more undergoing intense star formation. For Arp 299 A, we present PACS
spectrometer observations of high-J CO lines up to J=20-19 and JCMT
observations of CO and HCN to discern between UV heating and alternative
heating mechanisms. There is an immediately noticeable difference in the
spectra of Arp 299 A and Arp 299 B+C, with source A having brighter high-J CO
transitions. This is reflected in their respective spectral energy line
distributions. We find that photon-dominated regions (PDRs) are unlikely to
heat all the gas since a very extreme PDR is necessary to fit the high-J CO
lines. In addition, this extreme PDR does not fit the HCN observations, and the
dust spectral energy distribution shows that there is not enough hot dust to
match the amount expected from such an extreme PDR. Therefore, we determine
that the high-J CO and HCN transitions are heated by an additional mechanism,
namely cosmic ray heating, mechanical heating, or X-ray heating. We find that
mechanical heating, in combination with UV heating, is the only mechanism that
fits all molecular transitions. We also constrain the molecular gas mass of Arp
299 A to 3e9 Msun and find that we need 4% of the total heating to be
mechanical heating, with the rest UV heating
First detection of the [OI] 63-um emission from a redshift 6 dusty galaxy
We report a ground-based detection of the [OI] 63-um line in a z=6.027
gravitationally lensed dusty star-forming galaxy (DSFG) G09.83808 using the
APEX SEPIA 660 receiver, the first unambiguous detection of the [OI]63 line
beyond redshift 3, and the first obtained from the ground. The [OI]63 line is
robustly detected at 225 Jy km s, corresponding to an intrinsic
(de-lensed) luminosity of L. With the
[OI]63/[CII] luminosity ratio of 4, the [OI]63 line is the main coolant of the
neutral gas in this galaxy, in agreement with model predictions. The high
[OI]63 luminosity compensates for the pronounced [CII] deficit
([CII]/FIR). Using photon-dominated region models, we
derive a source-averaged gas density cm, and far-UV field
strength , comparable to the z=2-4 DSFG population. If G09.83808
represents a typical high-redshift DSFG, the [OI]63 line from z=6 non-lensed
DSFGs should be routinely detectable in ALMA Band 9 observations with 15
min on-source, opening a new window to study the properties of the earliest
DSFGs.Comment: Submitted to ApJ
Practical sand transport formula for non-breaking waves and currents
Open Access funded by Engineering and Physical Sciences Research Council Under a Creative Commons license Acknowledgements This work is part of the SANTOSS project (âSANd Transport in OScillatory flows in the Sheet-flow regimeâ) funded by the UK's EPSRC (GR/T28089/01) and STW in The Netherlands (TCB.6586). JW acknowledges Deltares strategic research funding under project number 1202359.09. Richard Soulsby is gratefully acknowledged for valuable discussions and feedback on the formula during the SANTOSS project.Peer reviewedPostprin
The Elusive Active Nucleus of NGC 4945
We present new HST NICMOS observations of NGC 4945, a starburst galaxy
hosting a highly obscured active nucleus that is one of the brightest
extragalactic sources at 100 keV. The HST data are complemented with ground
based [FeII] line and mid--IR observations. A 100pc-scale starburst ring is
detected in Pa alpha, while H_2 traces the walls of a super bubble opened by
supernova-driven winds. The conically shaped cavity is particularly prominent
in Pa alpha equivalent width and in the Pa alpha/H_2 ratio. Continuum images
are heavily affected by dust extinction and the nucleus of the galaxy is
located in a highly reddened region with an elongated, disk-like morphology. No
manifestation of the active nucleus is found, neither a strong point source nor
dilution in CO stellar features, which are expected tracers of AGN activity.
Even if no AGN traces are detected in the near-IR, with the currently available
data it is still not possible to establish whether the bolometric luminosity of
the object is powered by the AGN or by the starburst: we demonstrate that the
two scenarios constitute equally viable alternatives. However, the absence of
any signature other than in the hard X-rays implies that, in both scenarios,
the AGN is non-standard: if it dominates, it must be obscured in all
directions, conversely, if the starburst dominates, the AGN must lack UV
photons with respect to X-rays. An important conclusion is that powerful AGNs
can be hidden even at mid-infrared wavelengths and, therefore, the nature of
luminous dusty galaxies cannot be always characterized by long-wavelength data
alone but must be complemented with sensitive hard X-ray observations.Comment: Accepted for publication in A&A, high quality color pictures
available at http://www.arcetri.astro.it/~marconi/colpic.htm
The Double Quasar Q2138-431: Lensing by a Dark Galaxy?
We report the discovery of a new gravitational lens candidate Q2138-431AB,
comprising two quasar images at a redshift of 1.641 separated by 4.5 arcsecs.
The spectra of the two images are very similar, and the redshifts agree to
better than 115 km.sec. The two images have magnitudes and
, and in spite of a deep search and image subtraction procedure, no
lensing galaxy has been found with . Modelling of the system
configuration implies that the mass-to-light ratio of any lensing galaxy is
likely to be around , with an absolute lower limit of
for an Einstein-de Sitter universe. We conclude that
the most likely explanation of the observations is gravitational lensing by a
dark galaxy, although it is possible we are seeing a binary quasar.Comment: 17 pages (Latex), 8 postscript figures included, accepted by MNRA
Radiative and mechanical feedback into the molecular gas of NGC 253
Starburst galaxies are undergoing intense periods of star formation.
Understanding the heating and cooling mechanisms in these galaxies can give us
insight to the driving mechanisms that fuel the starburst. Molecular emission
lines play a crucial role in the cooling of the excited gas. With SPIRE on the
Herschel Space Observatory we have observed the rich molecular spectrum towards
the central region of NGC 253. CO transitions from J=4-3 to 13-12 are observed
and together with low-J line fluxes from ground based observations, these lines
trace the excitation of CO. By studying the CO excitation ladder and comparing
the intensities to models, we investigate whether the gas is excited by UV
radiation, X-rays, cosmic rays, or turbulent heating. Comparing the CO
and CO observations to large velocity gradient models and PDR models we
find three main ISM phases. We estimate the density, temperature,and masses of
these ISM phases. By adding CO, HCN, and HNC line intensities, we are
able to constrain these degeneracies and determine the heating sources. The
first ISM phase responsible for the low-J CO lines is excited by PDRs, but the
second and third phases, responsible for the mid to high-J CO transitions,
require an additional heating source. We find three possible combinations of
models that can reproduce our observed molecular emission. Although we cannot
determine which of these are preferable, we can conclude that mechanical
heating is necessary to reproduce the observed molecular emission and cosmic
ray heating is a negligible heating source. We then estimate the mass of each
ISM phase; M for phase 1 (low-J CO lines), M for phase 2 (mid-J CO lines), and M for
phase 3 (high-J CO lines) for a total system mass of M
MOD/R : A knowledge assisted approach towards top-down only CMOS VLSI design
MOD/R models all views on the design space in relations. This is achieved by eliminating the package constraints, as are apparent in PCB oriented hardware description languages. Assisted by knowledge engineering it allows for a top-down, mostly hierarchical decomposition, virtually eliminating the need for bottom-up assembly
Learning Hybrid Process Models From Events: Process Discovery Without Faking Confidence
Process discovery techniques return process models that are either formal
(precisely describing the possible behaviors) or informal (merely a "picture"
not allowing for any form of formal reasoning). Formal models are able to
classify traces (i.e., sequences of events) as fitting or non-fitting. Most
process mining approaches described in the literature produce such models. This
is in stark contrast with the over 25 available commercial process mining tools
that only discover informal process models that remain deliberately vague on
the precise set of possible traces. There are two main reasons why vendors
resort to such models: scalability and simplicity. In this paper, we propose to
combine the best of both worlds: discovering hybrid process models that have
formal and informal elements. As a proof of concept we present a discovery
technique based on hybrid Petri nets. These models allow for formal reasoning,
but also reveal information that cannot be captured in mainstream formal
models. A novel discovery algorithm returning hybrid Petri nets has been
implemented in ProM and has been applied to several real-life event logs. The
results clearly demonstrate the advantages of remaining "vague" when there is
not enough "evidence" in the data or standard modeling constructs do not "fit".
Moreover, the approach is scalable enough to be incorporated in
industrial-strength process mining tools.Comment: 25 pages, 12 figure
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