1,217 research outputs found
Discovery potential for Higgs bosons beyond the SM
The discovery potential of the CMS detector for the MSSM neutral and charged
Higgs bosons at the LHC is presented based on studies with full detector
simulation and event reconstruction of the principal discovery channels.Comment: Prepared for International Europhysics Conference on High Energy
Physics (EPS-HEP2007), Manchester, England, 19-25 Jul 200
Facing the peat CO2 threat: digital mapping of Indonesian peatlands—a proposed methodology and its application
A distinct peak-flux distribution of the third class of gamma-ray bursts: A possible signature of X-ray flashes?
Gamma-ray bursts are the most luminous events in the Universe. Going beyond
the short-long classification scheme we work in the context of three burst
populations with the third group of intermediate duration and softest spectrum.
We are looking for physical properties which discriminate the intermediate
duration bursts from the other two classes. We use maximum likelihood fits to
establish group memberships in the duration-hardness plane. To confirm these
results we also use k-means and hierarchical clustering. We use Monte-Carlo
simulations to test the significance of the existence of the intermediate group
and we find it with 99.8% probability. The intermediate duration population has
a significantly lower peak-flux (with 99.94% significance). Also, long bursts
with measured redshift have higher peak-fluxes (with 98.6% significance) than
long bursts without measured redshifts. As the third group is the softest, we
argue that we have {related} them with X-ray flashes among the gamma-ray
bursts. We give a new, probabilistic definition for this class of events.Comment: accepted for publication in Ap
Monitoring Space Weather: Using Automated, Accurate Neural Network Based Whistler Segmentation for Whistler Inversion
It is challenging, yet important, to measure the - ever-changing - cold electron density in the plasmasphere. The cold electron density inside and outside of the plasmapause is a key parameter for radiation belt dynamics. One indirect measurement is through finding the velocity dispersion relation exhibited by lightning induced whistlers. The main difficulty of the method comes from low signal-to-noise ratios for most of the ground-based whistler components. To provide accurate electron density and L-shell measurements, whistler components need to be detectable in the noisy background, and their characteristics need to be reliably determined. For this reason precise segmentation is needed on a spectrogram image. Here we present a fully automated way to perform such an image segmentation by leveraging the power of convolutional neural networks, a state-of-the-art method for computer vision tasks. Testing the proposed method against a manually, and semi-manually segmented whistler dataset achieved <10% relative electron density prediction error for 80% of the segmented whistler traces, while for the L-shell, the relative error is <5% for 90% of the cases. By segmenting more than 1 million additional real whistler traces from Rothera station Antarctica, logged over 9 years, seasonal changes in the average electron density were found. The variations match previously published findings, and confirm the capabilities of the image segmentation technique
Single acute stress-induced progesterone and ovariectomy alter cardiomyocyte contractile function in female rats
Aim To assess how ovarian-derived sex hormones (in particular
progesterone) modify the effects of single acute
stress on the mechanical and biochemical properties of
left ventricular cardiomyocytes in the rat.
Methods Non-ovariectomized (control, n = 8) and ovariectomized
(OVX, n = 8) female rats were kept under normal
conditions or were exposed to stress (control-S, n = 8
and OVX-S, n = 8). Serum progesterone levels were measured
using a chemiluminescent immunoassay. Left ventricular
myocardial samples were used for isometric force
measurements and protein analysis. Ca2+-dependent active
force (Factive), Ca2+-independent passive force (Fpassive),
and Ca2+-sensitivity of force production were determined
in single, mechanically isolated, permeabilized cardiomyocytes.
Stress- and ovariectomy-induced alterations in myofilament
proteins (myosin-binding protein C [MyBP-C], troponin
I [TnI], and titin) were analyzed by sodium dodecyl
sulfate gel electrophoresis using protein and phosphoprotein
stainings. Results Serum progesterone levels were significantly increased
in stressed rats (control-S, 35.6 ± 4.8 ng/mL and
OVX-S, 21.9 ± 4.0 ng/mL) compared to control (10 ± 2.9
ng/mL) and OVX (2.8 ± 0.5 ng/mL) groups. Factive was higher
in the OVX groups (OVX, 25.9 ± 3.4 kN/m2 and OVX-S,
26.3 ± 3.0 kN/m2) than in control groups (control, 16.4 ± 1.2
kN/m2 and control-S, 14.4 ± 0.9 kN/m2). Regarding the
potential molecular mechanisms, Factive correlated with
MyBP-C phosphorylation, while myofilament Ca2+-sensitivity
inversely correlated with serum progesterone levels
when the mean values were plotted for all animal groups.
Fpassive was unaffected by any treatment.
Conclusion Stress increases ovary-independent synthesis
and release of progesterone, which may regulate Ca2+-sensitivity
of force production in left ventricular cardiomyocytes.
Stress and female hormones differently alter Ca2+-
dependent cardiomyocyte contractile force production,
which may have pathophysiological importance during
stress conditions affecting postmenopausal women
Measurement of the inclusive cross-sections of single top-quark and top-antiquark t-channel production in pp collisions at √s=13 TeV with the ATLAS detector
High-ET isolated-photon plus jets production in pp collisions at s=8 TeV with the ATLAS detector
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