2,180 research outputs found
Can we predict the time of seedling emergence of spring wheat?
Non-Peer Reviewe
No-till can reduce the risk of heat stress in wheat
Non-Peer ReviewedNo-till farming (NT) is increasing in the Canadian Prairies in recent years because of the economic and environment benefits and its potential to sequester atmospheric carbon into the soil. Because surface residue and stubble act as insulation and impedes the exchange rate of thermal energy between the soil and the atmosphere, lower root-zone temperatures in the NT fields compared with that in the conventionally tilled (CT) fields were widely observed in the spring. Some studies found that low temperatures under NT persisted to the mid-season or throughout the whole growing season. Little attention, however, has been paid to the impact of the cooling effect of NT on the grain yield of wheat. The objective of this study was to investigate if NT could alleviate heat stress and benefit yield
Ecosystem modeling: supermodel or coupling approach?
Non-Peer Reviewe
Variability survey in the CoRoT SRa01 field: Implications of eclipsing binary distribution on cluster formation in NGC 2264
Time-series photometry of the CoRoT field SRa01 was carried out with the
Berlin Exoplanet Search Telescope II (BEST II) in 2008/2009. A total of 1,161
variable stars were detected, of which 241 were previously known and 920 are
newly found. Several new, variable young stellar objects have been discovered.
The study of the spatial distribution of eclipsing binaries revealed the higher
relative frequency of Algols toward the center of the young open cluster NGC
2264. In general Algol frequency obeys an isotropic distribution of their
angular momentum vectors, except inside the cluster, where a specific
orientation of the inclinations is the case. We suggest that we see the orbital
plane of the binaries almost edge-on.Comment: 18 pages, 8 figures, accepted for publication in Ap
The Berlin Exoplanet Search Telescope II. Catalog of Variable Stars. I. Characterization of Three Southern Target Fields
A photometric survey of three Southern target fields with BEST II yielded the
detection of 2,406 previously unknown variable stars and an additional 617
stars with suspected variability. This study presents a catalog including their
coordinates, magnitudes, light curves, ephemerides, amplitudes, and type of
variability. In addition, the variability of 17 known objects is confirmed,
thus validating the results. The catalog contains a number of known and new
variables that are of interest for further astrophysical investigations, in
order to, e.g., search for additional bodies in eclipsing binary systems, or to
test stellar interior models.
Altogether, 209,070 stars were monitored with BEST II during a total of 128
nights in 2009/2010. The overall variability fraction of 1.2-1.5% in these
target fields is well comparable to similar ground-based photometric surveys.
Within the main magnitude range of , we identify
0.67(3)% of all stars to be eclipsing binaries, which indicates a completeness
of about one third for this particular type in comparison to space surveys.Comment: accepted to A
A Direct Reduction from k-Player to 2-Player Approximate Nash Equilibrium
We present a direct reduction from k-player games to 2-player games that
preserves approximate Nash equilibrium. Previously, the computational
equivalence of computing approximate Nash equilibrium in k-player and 2-player
games was established via an indirect reduction. This included a sequence of
works defining the complexity class PPAD, identifying complete problems for
this class, showing that computing approximate Nash equilibrium for k-player
games is in PPAD, and reducing a PPAD-complete problem to computing approximate
Nash equilibrium for 2-player games. Our direct reduction makes no use of the
concept of PPAD, thus eliminating some of the difficulties involved in
following the known indirect reduction.Comment: 21 page
Sub-femtosecond absolute timing precision with a 10 GHz hybrid photonic-microwave oscillator
We present an optical-electronic approach to generating microwave signals
with high spectral purity. By circumventing shot noise and operating near
fundamental thermal limits, we demonstrate 10 GHz signals with an absolute
timing jitter for a single hybrid oscillator of 420 attoseconds (1Hz - 5 GHz)
Endoscopic Cubital Tunnel Recurrence Rates
Cubital tunnel syndrome is the second most common nerve entrapment in the upper extremity. There are no current publications concerning the recurrence rates after endoscopic cubital tunnel release. The purpose of this study is to evaluate the recurrence rate of endoscopic cubital tunnel release compared to published reports of recurrence following open cubital tunnel procedures. We reviewed 134 consecutive cases of endoscopic cubital tunnel release in 117 patients. There were 104 cases in 94 patients with greater than 3 months follow-up. The mean follow-up time was 736 days. They were grouped using Dellon’s classification. Two literature control groups were used from published reports of recurrence rate following open cubital tunnel release. A recurrence was identified if the patient was symptom-free following surgery but had symptoms reappear 3 months or more after surgery as defined in the literature. Of the 104 cases, 92.31% had more than a 4-month follow-up. One case (0.96%) met the criteria for recurrence at 4 months postprocedure. Data were then compared to the literature control groups used from published reports of recurrence rates following open cubital tunnel release. Pooled, the combined controls had 22 of 180 cases (12.22%) with recurrences. The percentage of procedure recurrence varied significantly with p value equal to 0.0004. It is recognized that there is a lack of common classification and comparative analysis of these studies, but they do classify preoperative grading and recurrence similarly. We are 95% confident that our true recurrence rate is between 0.02% and 5.24% and that endoscopic cubital tunnel release has a recurrence rate, which is not higher than open cubital tunnel release literature controls
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