146 research outputs found
Supporting Flexible Processes with Adaptive Workflow and Case Handling
Workflow management technology has profoundly transformed the way complex tasks are being handled in modern, large-scale organizations. However, it is mostly those systems’ inherent lack of flexibility that hinders their broad acceptance, and that is perceived as annoyance by users. In this context, Adaptive Process Management and Case Handling provide two very different paradigms, which both attempt to make process management more flexible and user-friendly. In this paper, we compare strengths and weaknesses of these two paradigms, and point out situations in which each is particularly appropriate. We further outline ways, in which either technology can be enhanced by crucial concepts from the other. This integration of flexibility approaches has the potential to remedy fundamental problems still present in each technology on its own
Space and Ground Based Pulsation Data of Eta Bootis Explained with Stellar Models Including Turbulence
The space telescope MOST is now providing us with extremely accurate low
frequency p-mode oscillation data for the star Eta Boo. We demonstrate in this
paper that these data, when combined with ground based measurements of the high
frequency p-mode spectrum, can be reproduced with stellar models that include
the effects of turbulence in their outer layers. Without turbulence, the l=0
modes of our models deviate from either the ground based or the space data by
about 1.5-4.0 micro Hz. This discrepancy can be completely removed by including
turbulence in the models and we can exactly match 12 out of 13 MOST frequencies
that we identified as l=0 modes in addition to 13 out of 21 ground based
frequencies within their observational 2 sigma tolerances. The better agreement
between model frequencies and observed ones depends for the most part on the
turbulent kinetic energy which was taken from a 3D convection simulation for
the Sun.Comment: 13 pages, 7 figures, ApJ in pres
The Tropical Forest and Fire Emissions Experiment: method evaluation of volatile organic compound emissions measured by PTR-MS, FTIR, and GC from tropical biomass burning
Volatile Organic Compound (VOC) emissions from fires in tropical forest fuels were quantified using Proton-Transfer-Reaction Mass Spectrometry (PTRMS), Fourier Transform Infrared Spectroscopy (FTIR) and gas chromatography (GC) coupled to PTRMS (GC-PTR-MS). We investigated VOC emissions from 19 controlled laboratory fires at the USFS (United States Forest Service) Fire Sciences Laboratory and 16 fires during an intensive airborne field campaign during the peak of the burning season in Brazil in 2004. The VOC emissions were dominated by oxygenated VOCs (OVOC) (OVOC/NMHC ~4:1, NMHC: non-methane hydrocarbons) The specificity of the PTR-MS instrument, which measures the mass to charge ratio of VOCs ionized by H<sub>3</sub>O<sup>+</sup> ions, was validated by gas chromatography and by intercomparing in-situ measurements with those obtained from an open path FTIR instrument. Emission ratios for methyl vinyl ketone, methacrolein, crotonaldehyde, acrylonitrile and pyrrole were measured in the field for the first time. Our measurements show a higher contribution of OVOCs than previously assumed for modeling purposes. Comparison of fresh (<15 min) and aged (>1 h&ndash;1 d) smoke suggests altered emission ratios due to gas phase chemistry for acetone but not for acetaldehyde and methanol. Emission ratios for numerous, important, reactive VOCs with respect to acetonitrile (a biomass burning tracer) are presented
POLY(GLYCIDYL METHACRYLATE-DIVINYLBENZENE) MONOLITHIC CAPILLARY AS A STATIONARY PHASE FOR THE REVERSED-PHASE CHROMATOGRAPHIC SEPARATION OF PROTEINS
Capillary column with monolithic stationary phase was prepared from silanized fused-silica capillary of 200 µm I.D. by in situ free radical polymerization of divinylbenzene with glycidy methacrylate in the presence of decanol and tetrahydrofuran as porogens. The hydrodynamic and chromatographic properties of this monolith, such as backpressure at different flow-rate, pore size distribution, van Deemter plot and the effect of varying gradient-rate were investigated. Poly(glycidyl methacrylate-divinylbenzene) monolithic capillary has been used successfully for the reversed-phase chromatographic separation of proteins.
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Keywords: monolithic stationary phase, poly(glycidyl methacrylate-divinylbenzene), protein
The Tropical Forest and Fire Emissions Experiment: Overview and Airborne Fire Emission Factor Measurements
The Tropical Forest and Fire Emissions Experiment (TROFFEE) used laboratory measurements followed by airborne and ground based field campaigns during the 2004 Amazon dry season to quantify the emissions from pristine tropical forest and several plantations as well as the emissions, fuel consumption, and fire ecology of tropical deforestation fires. The airborne campaign used an Embraer 110B aircraft outfitted with whole air sampling in canisters, mass-calibrated nephelometry, ozone by UV absorbance, Fourier transform infrared spectroscopy (FTIR), and proton-transfer mass spectrometry (PTR-MS) to measure PM(10), O(3), CO(2), CO, NO, NO(2), HONO, HCN, NH(3), OCS, DMS, CH(4), and up to 48 non-methane organic compounds (NMOC). The Brazilian smoke/haze layers extended to 2 - 3 km altitude, which is much lower than the 5 - 6 km observed at the same latitude, time of year, and local time in Africa in 2000. Emission factors (EF) were computed for the 19 tropical deforestation fires sampled and they largely compare well to previous work. However, the TROFFEE EF are mostly based on a much larger number of samples than previously available and they also include results for significant emissions not previously reported such as: nitrous acid, acrylonitrile, pyrrole, methylvinylketone, methacrolein, crotonaldehyde, methylethylketone, methylpropanal, \u27\u27 acetol plus methylacetate,\u27\u27 furaldehydes, dimethylsulfide, and C(1)-C(4) alkyl nitrates. Thus, we recommend these EF for all tropical deforestation fires. The NMOC emissions were similar to 80% reactive, oxygenated volatile organic compounds (OVOC). Our EF for PM(10) (17.8 +/- 4 g/kg) is similar to 25% higher than previously reported for tropical forest fires and may reflect a trend towards, and sampling of, larger fires than in earlier studies. A large fraction of the total burning for 2004 likely occurred during a two-week period of very low humidity. The combined output of these fires created a massive \u27\u27 mega-plume \u27\u27 \u3e 500 km across that we sampled on 8 September. The mega-plume contained high PM(10) and 10 - 50 ppbv of many reactive species such as O(3), NH(3), NO(2), CH(3)OH, and organic acids. This is an intense and globally important chemical processing environment that is still poorly understood. The mega-plume or \u27\u27 white ocean \u27\u27 of smoke covered a large area in Brazil, Bolivia, and Paraguay for about one month. The smoke was transported \u3e 2000 km to the southeast while remaining concentrated enough to cause a 3 - 4-fold increase in aerosol loading in the S (a) over tildeo Paulo area for several days
Line-profile tomography of exoplanet transits -- II. A gas-giant planet transiting a rapidly-rotating A5 star
Most of our knowledge of extrasolar planets rests on precise radial-velocity
measurements, either for direct detection or for confirmation of the planetary
origin of photometric transit signals. This has limited our exploration of the
parameter space of exoplanet hosts to solar- and later-type, sharp-lined stars.
Here we extend the realm of stars with known planetary companions to include
hot, fast-rotating stars. Planet-like transits have previously been reported in
the lightcurve obtained by the SuperWASP survey of the A5 star HD15082
(WASP-33; V=8.3, v sin i = 86 km/sec). Here we report further photometry and
time-series spectroscopy through three separate transits, which we use to
confirm the existence of a gas giant planet with an orbital period of 1.22d in
orbit around HD15082. From the photometry and the properties of the planet
signal travelling through the spectral line profiles during the transit we
directly derive the size of the planet, the inclination and obliquity of its
orbital plane, and its retrograde orbital motion relative to the spin of the
star. This kind of analysis opens the way to studying the formation of planets
around a whole new class of young, early-type stars, hence under different
physical conditions and generally in an earlier stage of formation than in
sharp-lined late-type stars. The reflex orbital motion of the star caused by
the transiting planet is small, yielding an upper mass limit of 4.1 Jupiter
masses on the planet. We also find evidence of a third body of sub-stellar mass
in the system, which may explain the unusual orbit of the transiting planet. In
HD 15082, the stellar line profiles also show evidence of non-radial
pulsations, clearly distinct from the planetary transit signal. This raises the
intriguing possibility that tides raised by the close-in planet may excite or
amplify the pulsations in such stars.Comment: 9 pages, 6 figures, accepted for publication in MNRA
Core Overshoot: An Improved Treatment and Constraints from Seismic Data
We present a comprehensive set of stellar evolution models for Procyon A in
an effort to guide future measurements of both traditional stellar parameters
and seismic frequencies towards constraining the amount of core overshoot in
Procyon A and possibly other stars. Current observational measurements of
Procyon A when combined with traditional stellar modeling only place a large
upper limit on overshoot of alphaOV < 1.1. By carrying out a detailed pulsation
analysis, we further demonstrate, how p- and g-mode averaged spacings can be
used to gain better estimates of the core size. For both p- and g-modes, the
frequency spacings for models without overshoot are clearly separated from the
models with overshoot. In addition, measurements of the l=0 averaged small
p-mode spacings could be used to establish Procyon A's evolutionary stage. For
a fixed implementation of overshoot and under favorable circumstances, the
g-mode spacings can be used to determine the overshoot extent to an accuracy of
+-0.05 Hp. However, we stress that considerable confusion is added due to the
unknown treatment of the overshoot region. This ambiguity might be removed by
analyzing many different stars. A simple non-local convection theory developed
by Kuhfuss is implemented in our stellar evolution code and contrasted with the
traditional approaches. We show that this theory supports a moderate increase
of the amount of convective overshoot with stellar mass of Delta(alphaOV) =
+0.10 between 1.5 Msun and 15 Msun. This theory places an upper limit on
Procyon A's core overshoot extent of ~0.4 Hp which matches the limit imposed by
Roxburgh's integral criterion.Comment: 45 pages, 26 figures, accepted in Ap
Impact of an in-hospital endocarditis team and a state-wide endocarditis network on perioperative outcomes
Background: Infective endocarditis (IE) requires multidisciplinary management. We established an endocarditis team within our hospital in 2011 and a state-wide endocarditis network with referring hospitals in 2015. We aimed to investigate their impact on perioperative outcomes. Methods: We retrospectively analyzed data from patients operated on for IE in our center between 01/2007 and 03/2018. To investigate the impact of the endocarditis network on referral latency and pre-operative complications we divided patients into two eras: before ( n = 409) and after ( n = 221) 01/2015. To investigate the impact of the endocarditis team on post-operative outcomes we conducted multivariate binary logistic regression analyses for the whole population. Kaplan–Meier estimates of 5-year survival were reported. Results: In the second era, after establishing the endocarditis network, the median time from symptoms to referral was halved (7 days (interquartile range: 2–19) vs. 15 days (interquartile range: 6–35)), and pre-operative endocarditis-related complications were reduced, i.e., stroke (14% vs. 27%, p < 0.001), heart failure (45% vs. 69%, p < 0.001), cardiac abscesses (24% vs. 34%, p = 0.018), and acute requirement of hemodialysis (8% vs. 14%, p = 0.026). In both eras, a lack of recommendations from the endocarditis team was an independent predictor for in-hospital mortality (adjusted odds ratio: 2.12, 95% CI: 1.27–3.53, p = 0.004) and post-operative stroke (adjusted odds ratio: 2.23, 95% CI: 1.12–4.39, p = 0.02), and was associated with worse 5-year survival (59% vs. 40%, log-rank < 0.001). Conclusion: The establishment of an endocarditis network led to the earlier referral of patients with fewer pre-operative endocarditis-related complications. Adhering to endocarditis team recommendations was an independent predictor for lower post-operative stroke and in-hospital mortality, and was associated with better 5-year survival
Current Issues in Asteroseismology
In this contribution we briefly review some of the current issues and
promises for the future by asteroseismology. We are entering a new phase in
this field driven by the wealth of data that has been collected and data that
will soon be available for asteroseismology across the HR Diagram. Major
difficulties in the descriptions of stellar interiors that arose in the second
half of the 20th century may now be in part addressed and solved (this is the
expectation!) by asteroseismology with unprecedented precision. In this
contribution we list some of the key open questions in stellar physics, the
seismic data we expect to collect in the near future, and some techniques that
will provide the tools to connect data and models.Comment: 9 pages, 2 figures - to appear in Helioseismology, Asteroseismology
and MHD Connections, (Eds) L. Gizon et al., Journal of Physics Conference
Series, 2008 [Revision 1 - english; Revision 2 - references
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