194 research outputs found
Lifecycle-Support in Architectures for Ontology-Based Information Systems
Ontology-based applications play an increasingly important role in the public and corporate Semantic Web. While today there exist a range of tools and technologies to support specific ontology engineering and management activities, architectural design guidelines for building ontology-based applications are missing. In this paper, we present an architecture for ontology-based applicationsâcovering the complete ontology-lifecycleâthat is intended to support
software engineers in designing and developing ontology based-applications.
We illustrate the use of the architecture in a concrete case study using the NeOn toolkit as one implementation of the architecture
Rotation-tunneling spectrum and astrochemical modeling of dimethylamine, CHNHCH, and searches for it in space
Methylamine has been the only simple alkylamine detected in the interstellar
medium for a long time. With the recent secure and tentative detections of
vinylamine and ethylamine, respectively, dimethylamine has become a promising
target for searches in space. Its rotational spectrum, however, has been known
only up to 45 GHz until now. Here we investigate the rotation-tunneling
spectrum of dimethylamine in selected regions between 76 and 1091 GHz using
three different spectrometers in order to facilitate its detection in space.
The quantum number range is extended to and , yielding an
extensive set of accurate spectroscopic parameters. To search for
dimethylamine, we refer to the spectral line survey ReMoCA carried out with the
Atacama Large Millimeter/submillimeter Array toward the high-mass star-forming
region Sagittarius B2(N) and a spectral line survey of the molecular cloud
G+0.6930.027 employing the IRAM 30 m and Yebes 40 m radio telescopes. We
report nondetections of dimethylamine toward the hot molecular cores Sgr
B2(N1S) and Sgr B2(N2b) as well as G+0.6930.027 which imply that
dimethylamine is at least 14, 4.5 and 39 times less abundant than methylamine
toward these sources, respectively. The observational results are compared to
computational results from a gas-grain astrochemical model. The modeled
methylamine to dimethylamine ratios are compatible with the observational
ratios. However, the model produces too much ethylamine compared with
methylamine which could mean that the already fairly low levels of
dimethylamine in the models may also be too high.Comment: Mon. Not. R. Astron. Soc., accepted. 33 pages including tables,
figures, and appendi
Investigation of the rotational spectrum of CDOD and an astronomical search toward IRAS 162932422
Solar-type prestellar cores and protostars display large amounts of
deuterated organic molecules. Recent findings on CHDOH and CDOH toward
IRAS 16293-2422 suggest that even fully deuterated methanol, CDOD, may be
detectable as well. However, searches for CDOD are hampered in particular
by the lack of intensity information from a spectroscopic model. The objective
of the present investigation is to develop a spectroscopic model of CDOD in
low-lying torsional states that is sufficiently accurate to facilitate searches
for this isotopolog in space. We carried out a new measurement campaign for
CDOD involving two spectroscopic laboratories that covers the 34 GHz-1.1
THz range. A torsion-rotation Hamiltonian model based on the rho-axis method
was employed for our analysis. Our resulting model describes the ground and
first excited torsional states of CDOD well up to quantum numbers and . We derived a line list for radio-astronomical
observations from this model that is accurate up to at least 1.1 THz and should
be sufficient for all types of radio-astronomical searches for this methanol
isotopolog. This line list was used to search for CDOD in data from the
Protostellar Interferometric Line Survey of IRAS 162932422 obtained with the
Atacama Large Millimeter/submillimeter Array. While we found several emission
features that can be attributed largely to CDOD, their number is still not
sufficiently high enough to establish a clear detection. Nevertheless, the
estimate of 2 cm derived for the CDOD column density
may be viewed as an upper limit that can be compared to column densities of
CDOH, CHOD, and CHOH. The comparison indicates that the CDOD
column density toward IRAS 16293-2422 is in line with the enhanced D/H ratios
observed for multiply deuterated complex organic molecules.Comment: 10 pages total, including figures, tables, and references; abstract
slightly shortened; Astron. Astrophys., accepte
Interstellar detection of CCC and high-precision laboratory measurements near 2THz
ABSTRACT We describe more fully our original tentative interstellar detection of the triatomic pure carbon chain molecule, CCC, in absorption toward the Galactic center source Sgr B2
Coding Efficiency of Fly Motion Processing Is Set by Firing Rate, Not Firing Precision
To comprehend the principles underlying sensory information processing, it is important to understand how the nervous system deals with various sources of perturbation. Here, we analyze how the representation of motion information in the fly's nervous system changes with temperature and luminance. Although these two environmental variables have a considerable impact on the fly's nervous system, they do not impede the fly to behave suitably over a wide range of conditions. We recorded responses from a motion-sensitive neuron, the H1-cell, to a time-varying stimulus at many different combinations of temperature and luminance. We found that the mean firing rate, but not firing precision, changes with temperature, while both were affected by mean luminance. Because we also found that information rate and coding efficiency are mainly set by the mean firing rate, our results suggest that, in the face of environmental perturbations, the coding efficiency is improved by an increase in the mean firing rate, rather than by an increased firing precision
Accurate laboratory rest frequencies of vibrationally excited CO up to and up to 2 THz
Astronomical observations of (sub)millimeter wavelength pure rotational
emission lines of the second most abundant molecule in the Universe, CO, hold
the promise of probing regions of high temperature and density in the innermost
parts of circumstellar envelopes. The rotational spectrum of vibrationally
excited CO up to \varv = 3 has been measured in the laboratory between 220
and 1940 GHz with relative accuracies up to , corresponding
to kHz near 1 THz. The rotational constant and the quartic
distortion parameter have been determined with high accuracy and even the
sextic distortion term was determined quite well for \varv = 1 while
reasonable estimates of were obtained for \varv = 2 and 3. The present
data set allows for the prediction of accurate rest frequencies of
vibrationally excited CO well beyond 2 THz.Comment: Astron. Astrophys, accepted; 5 pages, 2 Figures, 2 Table
Comparative assessment of phototherapy protocols for reduction of oxidative stress in partially transected spinal cord slices undergoing secondary degeneration
Background: Red/near-infrared light therapy (R/NIR-LT) has been developed as a treatment for a range of conditions, including injury to the central nervous system (CNS). However, clinical trials have reported variable or sub-optimal outcomes, possibly because there are few optimized treatment protocols for the different target tissues. Moreover, the low absolute, and wavelength dependent, transmission of light by tissues overlying the target site make accurate dosing problematic. Results: In order to optimize light therapy treatment parameters, we adapted a mouse spinal cord organotypic culture model to the rat, and characterized myelination and oxidative stress following a partial transection injury. The ex vivo model allows a more accurate assessment of the relative effect of different illumination wavelengths (adjusted for equal quantal intensity) on the target tissue. Using this model, we assessed oxidative stress following treatment with four different wavelengths of light: 450 nm (blue); 510 nm (green); 660 nm (red) or 860 nm (infrared) at three different intensities: 1.93 Ă 10Âčⶠ(low); 3.85 Ă 10Âčⶠ(intermediate) and 7.70 Ă 10Âčⶠ(high) photons/cmÂČ/s. We demonstrate that the most effective of the tested wavelengths to reduce immunoreactivity of the oxidative stress indicator 3-nitrotyrosine (3NT) was 660 nm. 860 nm also provided beneficial effects at all tested intensities, significantly reducing oxidative stress levels relative to control (p †0.05). Conclusions: Our results indicate that R/NIR-LT is an effective antioxidant therapy, and indicate that effective wavelengths and ranges of intensities of treatment can be adapted for a variety of CNS injuries and conditions, depending upon the transmission properties of the tissue to be treated.12 page(s
Neutrophil depletion reduces edema formation and tissue loss following traumatic brain injury in mice
Background: Brain edema as a result of secondary injury following traumatic brain injury (TBI) is a major clinical concern. Neutrophils are known to cause increased vascular permeability leading to edema formation in peripheral tissue, but their role in the pathology following TBI remains unclear. Methods: In this study we used controlled cortical impact (CCI) as a model for TBI and investigated the role of neutrophils in the response to injury. The outcome of mice that were depleted of neutrophils using an anti-Gr-1 antibody was compared to that in mice with intact neutrophil count. The effect of neutrophil depletion on blood-brain barrier function was assessed by Evan's blue dye extravasation, and analysis of brain water content was used as a measurement of brain edema formation (24 and 48 hours after CCI). Lesion volume was measured 7 and 14 days after CCI. Immunohistochemistry was used to assess cell death, using a marker for cleaved caspase-3 at 24 hours after injury, and microglial/macrophage activation 7 days after CCI. Data were analyzed using Mann-Whitney test for non-parametric data. Results: Neutrophil depletion did not significantly affect Evan's blue extravasation at any time-point after CCI. However, neutrophil-depleted mice exhibited a decreased water content both at 24 and 48 hours after CCI indicating reduced edema formation. Furthermore, brain tissue loss was attenuated in neutropenic mice at 7 and 14 days after injury. Additionally, these mice had a significantly reduced number of activated microglia/macrophages 7 days after CCI, and of cleaved caspase-3 positive cells 24 h after injury. Conclusion: Our results suggest that neutrophils are involved in the edema formation, but not the extravasation of large proteins, as well as contributing to cell death and tissue loss following TBI in mice
Biomarkers for Severity of Spinal Cord Injury in the Cerebrospinal Fluid of Rats
One of the major challenges in management of spinal cord injury (SCI) is that the assessment of injury severity is often imprecise. Identification of reliable, easily quantifiable biomarkers that delineate the severity of the initial injury and that have prognostic value for the degree of functional recovery would significantly aid the clinician in the choice of potential treatments. To find such biomarkers we performed quantitative liquid chromatography-mass spectrometry (LC-MS/MS) analyses of cerebrospinal fluid (CSF) collected from rats 24 h after either a moderate or severe SCI. We identified a panel of 42 putative biomarkers of SCI, 10 of which represent potential biomarkers of SCI severity. Three of the candidate biomarkers, Ywhaz, Itih4, and Gpx3 were also validated by Western blot in a biological replicate of the injury. The putative biomarkers identified in this study may potentially be a valuable tool in the assessment of the extent of spinal cord damage
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