1,239 research outputs found
The Pulsed Neutron Beam EDM Experiment
We report on the Beam EDM experiment, which aims to employ a pulsed cold
neutron beam to search for an electric dipole moment instead of the established
use of storable ultracold neutrons. We present a brief overview of the basic
measurement concept and the current status of our proof-of-principle Ramsey
apparatus
The Wendelstein Calar Alto Pixellensing Project (WeCAPP): the M31 Nova catalogue
We present light curves from the novae detected in the long-term, M31
monitoring WeCAPP project. The goal of WeCAPP is to constrain the compact dark
matter fraction of the M31 halo with microlensing observations. As a by product
we have detected 91 novae benefiting from the high cadence and highly sensitive
difference imaging technique required for pixellensing. We thus can now present
the largest CCD and optical filters based nova light curve sample up-to-date
towards M31. We also obtained thorough coverage of the light curve before and
after the eruption thanks to the long-term monitoring. We apply the nova
taxonomy proposed by Strope et al. (2010) to our nova candidates and found 29
S-class novae, 10 C-class novae, 2 O-class novae and 1 J-class nova. We have
investigated the universal decline law advocated by Hachichu and Kato (2006) on
the S-class novae. In addition, we correlated our catalogue with the literature
and found 4 potential recurrent novae. Part of our catalogue has been used to
search for optical counter-parts of the super soft X-ray sources detected in
M31 (Pietsch et al. 2005). Optical surveys like WeCAPP, and coordinated with
multi-wavelength observation, will continue to shed light on the underlying
physical mechanism of novae in the future.Comment: 15 pages, 15 figures, 7 tables, A&A accepted for publication. The
appendix is stored in the Data Conservanc
The High Osmolarity Glycerol Mitogen-Activated Protein Kinase regulates glucose catabolite repression in filamentous fungi
This is the final version. Available from the publisher via the DOI in this record.The utilization of different carbon sources in filamentous fungi underlies a complex regulatory network governed by signaling events of different protein kinase pathways, including
the high osmolarity glycerol (HOG) and protein kinase A (PKA) pathways. This work unraveled cross-talk events between these pathways in governing the utilization of preferred (glucose) and non-preferred (xylan, xylose) carbon sources in the reference fungus Aspergillus
nidulans. An initial screening of a library of 103 non-essential protein kinase (NPK) deletion
strains identified several mitogen-activated protein kinases (MAPKs) to be important for carbon catabolite repression (CCR). We selected the MAPKs Ste7, MpkB, and PbsA for further
characterization and show that they are pivotal for HOG pathway activation, PKA activity,
CCR via regulation of CreA cellular localization and protein accumulation, as well as for
hydrolytic enzyme secretion. Protein-protein interaction studies show that Ste7, MpkB, and
PbsA are part of the same protein complex that regulates CreA cellular localization in the
presence of xylan and that this complex dissociates upon the addition of glucose, thus allowing CCR to proceed. Glycogen synthase kinase (GSK) A was also identified as part of this
protein complex and shown to potentially phosphorylate two serine residues of the HOG
MAPKK PbsA. This work shows that carbon source utilization is subject to cross-talk regulation by protein kinases of different signaling pathways. Furthermore, this study provides a
model where the correct integration of PKA, HOG, and GSK signaling events are required
for the utilization of different carbon sources.Fundac¸ão de Amparo à Pesquisa do Estado de São Paulo (FAPESP
Evolution of the polarization of the optical afterglow of the gamma-ray burst GRB 030329
We report 31 polarimetric observations of the afterglow of GRB 030329 with
high signal-to-noise and high sampling frequency. We establish the polarization
light curve, detect sustained polarization at the percent level, and find
significant variability of polarization degree and angle. The data imply that
the afterglow magnetic field has small coherence length and is mostly random,
probably generated by turbulence.Comment: Nature 426 (13. Nov. 2003), 2 figure
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