255 research outputs found
Spectral hardness evolution characteristics of tracking Gamma-ray Burst pulses
Employing a sample presented by Kaneko et al. (2006) and Kocevski et al.
(2003), we select 42 individual tracking pulses (here we defined tracking as
the cases in which the hardness follows the same pattern as the flux or count
rate time profile) within 36 Gamma-ray Bursts (GRBs) containing 527
time-resolved spectra and investigate the spectral hardness, (where
is the maximum of the spectrum), evolutionary
characteristics. The evolution of these pulses follow soft-to-hard-to-soft (the
phase of soft-to-hard and hard-to-soft are denoted by rise phase and decay
phase, respectively) with time. It is found that the overall characteristics of
of our selected sample are: 1) the evolution in the rise
phase always start on the high state (the values of are always
higher than 50 keV); 2) the spectra of rise phase clearly start at higher
energy (the median of are about 300 keV), whereas the spectra of
decay phase end at much lower energy (the median of are about 200
keV); 3) the spectra of rise phase are harder than that of the decay phase and
the duration of rise phase are much shorter than that of decay phase as well.
In other words, for a complete pulse the initial is higher than the
final and the duration of initial phase (rise phase) are much
shorter than the final phase (decay phase). This results are in good agreement
with the predictions of Lu et al. (2007) and current popular view on the
production of GRBs. We argue that the spectral evolution of tracking pulses may
be relate to both of kinematic and dynamic process even if we currently can not
provide further evidences to distinguish which one is dominant. Moreover, our
statistical results give some witnesses to constrain the current GRB model.Comment: 32 pages, 26 figures, 3 tables, accepted for publication in New
Astronom
A Linear Regression Predictor for Identifying N 6 -Methyladenosine Sites Using Frequent Gapped K-mer Pattern
N6-methyladenosine (m 6 A) is one of the most common and abundant modifications in RNA, which is related to many biological processes in humans. Abnormal RNA modifications are often associated with a series of diseases, including tumors, neurogenic diseases, and embryonic retardation. Therefore, identifying m 6 A sites is of paramount importance in the post-genomic age. Although many lab-based methods have been proposed to annotate m 6 A sites, they are time consuming and cost ineffective. In view of the drawbacks of the intrinsic methods in RNA sequence recognition, computational methods are suggested as a supplement to identify m 6 A sites. In this study, we develop a novel feature extraction algorithm based on the frequent gapped k-mer pattern (FGKP) and apply the linear regression to construct the prediction model. The new predictor is used to identify m 6 A sites in the Saccharomyces cerevisiae database. It has been shown by the 10-fold cross-validation that the performance is better than that of recent methods. Comparative results indicate that our model has great potential to become a useful and effective tool for genome analysis and gain more insights for locating m 6 A sites
Restoration of factorization for low hadron hadroproduction
We discuss the applicability of the factorization theorem to low-
hadron production in hadron-hadron collision in a simple toy model, which
involves only scalar particles and gluons. It has been shown that the
factorization for high- hadron hadroproduction is broken by soft gluons in
the Glauber region, which are exchanged among a transverse-momentum-dependent
(TMD) parton density and other subprocesses of the collision. We explain that
the contour of a loop momentum can be deformed away from the Glauber region at
low , so the above residual infrared divergence is factorized by means of
the standard eikonal approximation. The factorization is then restored in
the sense that a TMD parton density maintains its universality. Because the
resultant Glauber factor is independent of hadron flavors, experimental
constraints on its behavior are possible. The factorization can also be
restored for the transverse single-spin asymmetry in hadron-hadron collision at
low in a similar way, with the residual infrared divergence being
factorized into the same Glauber factor.Comment: 12 pages, 2 figures, version to appear in EPJ
Dispatcher-assisted cardiopulmonary resuscitation for paediatric out-of-hospital cardiac arrest
Aim
To evaluate communication issues during dispatcher-assisted cardiopulmonary resuscitation (DACPR) for paediatric out-of-hospital cardiac arrest in a structured manner to facilitate recommendations for training improvement.
Methods
A retrospective observational study evaluated DACPR communication issues using the SACCIA ® Safe Communication typology (Sufficiency, Accuracy, Clarity, Contextualization, Interpersonal Adaptation). Telephone recordings of 31 cases were transcribed verbatim and analysed with respect to encoding, decoding and transactional communication issues.
Results
Sixty SACCIA communication issues were observed in the 31 cases, averaging 1.9 issues per case. A majority of the issues were related to sufficiency (35%) and accuracy (35%) of communication between dispatcher and caller. Situation specific guideline application was observed in CPR practice, (co)counting and methods of compressions.
Conclusion
This structured evaluation identified specific issues in paediatric DACPR communication. Our training recommendations focus on situation and language specific guideline application and moving beyond verbal communication by utilizing the smart phone’s functions. Prospective efforts are necessary to follow-up its translation into better paediatric DACPR outcomes
Evaluation of Hungarian Wines for Resveratrol by Overpressured Layer Chromatography
A method, including solid phase extraction sample preparation, overpressured layer chromatographic separation and subsequent densitometric evaluation, was developed for measurement of total resveratrol (cis- and trans-isomers) content of wine. The amount of resveratrol was determined in wine samples from different winemaking regions of Hungary. The total resveratrol was high in Hungarian red wines (3.6–11 mg/L), and much lower in white ones (0.04–1.5 mg/L)
News from the Muon (g-2) Experiment at BNL
The magnetic moment anomaly a_mu = (g_mu - 2) / 2 of the positive muon has
been measured at the Brookhaven Alternating Gradient Synchrotron with an
uncertainty of 0.7 ppm. The new result, based on data taken in 2000, agrees
well with previous measurements. Standard Model evaluations currently differ
from the experimental result by 1.6 to 3.0 standard deviations.Comment: Talk presented at RADCOR - Loops and Legs 2002, Kloster Banz,
Germany, September 8-13 2002, to be published in Nuclear Physics B (Proc.
Suppl.); 5 pages, 3 figure
A Measurement of Psi(2S) Resonance Parameters
Cross sections for e+e- to hadons, pi+pi- J/Psi, and mu+mu- have been
measured in the vicinity of the Psi(2S) resonance using the BESII detector
operated at the BEPC. The Psi(2S) total width; partial widths to hadrons,
pi+pi- J/Psi, muons; and corresponding branching fractions have been determined
to be Gamma(total)= (264+-27) keV; Gamma(hadron)= (258+-26) keV, Gamma(mu)=
(2.44+-0.21) keV, and Gamma(pi+pi- J/Psi)= (85+-8.7) keV; and Br(hadron)=
(97.79+-0.15)%, Br(pi+pi- J/Psi)= (32+-1.4)%, Br(mu)= (0.93+-0.08)%,
respectively.Comment: 8 pages, 6 figure
A Diffractive Study of Parametric Process in Nonlinear Photonic Crystals
We report a general description of quasi-phase-matched parametric process in
nonlinear photonic crystals (NLPC) by extending the conventional X-ray
diffraction theory in solids. Under the virtual wave approximation,
phase-matching resonance is equivalent to the diffraction of the scattered
virtual wave. Hence a modified NLPC Ewald construction can be built up, which
illustrates the nature of the accident for the diffraction of the virtual wave
in NLPC and further reveals the complete set of diffractions of the virtual
wave for both of the air-dielectric and dielectric-dielectric contacts. We show
the two basic linear sequences, the anti-stacking and para-stacking linear
sequences, in one-dimension (1D) NLPC and present a general rule for multiple
phase-matching resonances in 1D NLPC. The parameters affecting the NLPC
structure factor are investigated, which indicate that not only the Ewald
construction but also the relative NLPC atom size together determine whether a
diffraction of the virtual wave can occur in 2D NLPC. The results also show
that 1D NLPC is a better choice than 2D NLPC for a single parametric process
Direct Measurements of the Branching Fractions for and and Determinations of the Form Factors and
The absolute branching fractions for the decays and
are determined using singly
tagged sample from the data collected around 3.773 GeV with the
BES-II detector at the BEPC. In the system recoiling against the singly tagged
meson, events for and events for decays are observed. Those yield
the absolute branching fractions to be and . The
vector form factors are determined to be
and . The ratio of the two form
factors is measured to be .Comment: 6 pages, 5 figure
Measurements of J/psi Decays into 2(pi+pi-)eta and 3(pi+pi-)eta
Based on a sample of 5.8X 10^7 J/psi events taken with the BESII detector,
the branching fractions of J/psi--> 2(pi+pi-)eta and J/psi-->3(pi+pi-)eta are
measured for the first time to be (2.26+-0.08+-0.27)X10^{-3} and
(7.24+-0.96+-1.11)X10^{-4}, respectively.Comment: 11 pages, 6 figure
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