38,700 research outputs found
Observations of Large Scale Sidereal Anisotropy in 1 and 11 TeV cosmic rays from the MINOS experiment
The MINOS Near and Far Detectors are two large, functionally-identical,
steel-scintillating sampling calorimeters located at depths of 220 mwe and 2100
mwe respectively. The detectors observe the muon component of hadronic showers
produced from cosmic ray interactions with nuclei in the earth's atmosphere.
From the arrival direction of these muons, the anisotropy in arrival direction
of the cosmic ray primaries can be determined. The MINOS Near and Far Detector
have observed anisotropy on the order of 0.1% at 1 and 11 TeV respectively. The
amplitude and phase of the first harmonic at 1 TeV are
8.21.7(stat.) and (8.912.1(stat.)), and at
11 TeV are 3.80.5(stat.) and
(27.27.2(stat.)).Comment: 32nd International Cosmic Ray Conference, August 201
Search for the magnetic field of the O7.5 III star xi Persei
Cyclical wind variability is an ubiquitous but as yet unexplained feature
among OB stars. The O7.5 III(n)((f)) star xi Persei is the brightest
representative of this class on the Northern hemisphere. As its prominent
cyclical wind properties vary on a rotational time scale (2 or 4 days) the star
has been already for a long time a serious magnetic candidate. As the cause of
this enigmatic behavior non-radial pulsations and/or a surface magnetic field
are suggested. We present a preliminary report on our attempts to detect a
magnetic field in this star with high-resolution measurements obtained with the
spectropolarimeter Narval at TBL, France during 2 observing runs of 5 nights in
2006 and 5 nights in 2007. Only upper limits could be obtained, even with the
longest possible exposure times. If the star hosts a magnetic field, its
surface strength should be less than about 300 G. This would still be enough to
disturb the stellar wind significantly. From our new data it seems that the
amplitude of the known non-radial pulsations has changed within less than a
year, which needs further investigation.Comment: 2 pages, 6 figures, contributed poster at IAU Symposium 259 "Cosmic
Magnetic Fields: from Planets, to Stars and Galaxies", Tenerife, Spain,
November 3-7, 200
Feed additives : annual report 2009 of the National Reference Laboratory
This report of the National Reference Laboratory (NRL) for feed additives describes the activties employed in 2010. The main tasks of the NRL are: giving assistance to the European Union Reference Laboratort (EU-RL) on their request and advice and support the competent authority, the Dutch Ministry of Economic Affairs, Agriculture and Innovation - Department of Food, Animal and Consumer (EL&I-VDC
Consistency of Kernel Estimators of Heteroscedastic and Autocorrelated Covariance Matrices
Conditions are derived for the consistency of kernel estimators of the covariance matrix of a sum of vectors of dependent heterogeneous random variables, which match those of the currently best-known conditions for the central limit theorem, as required for a unified theory of asymptotic inference. These include finite moments of order no more than 2 + for > 0, trending variances, and variables which are near-epoch dependent on a mixing process, but not necessarily mixing. The results are also proved for the case of sample-dependent bandwidths.kernel estimator;matrices
The Impact of the Sarbanes-Oxley Act (SOX) on the Cost of Equity Capital of S&P Firms
This study examines the impact of SOX on the cost of equity capital for small and large S&P firms. The provisions of SOX aim to improve internal control systems and reduce information asymmetry by improving corporate governance systems and increasing transparency. Using a fixed-effects regression model, our findings suggest that the cost of equity capital has decreased post-SOX for the overall sample of firms, but more specifically for the small firms, which are usually associated with poor internal control systems and high information asymmetry. Collectively, our results provide evidence that SOX has had a positive impact on firms
- …