4,302 research outputs found
Spectral Lags Obtained by CCF of Smoothed Lightcurves
We present a new technique to calculate the spectral lags of gamma-ray bursts
(GRBs). Unlike previous processing methods, we first smooth the light curves of
gamma-ray bursts in high and low energy bands using the "Loess" filter, then,
we directly define the spectral lags as such to maximize the cross-correlation
function (CCF) between two smoothed light curves. This method is suitable for
various shapes of CCF; it effectively avoids the errors caused by manual
selections for the fitting function and fitting interval. Using the method, we
have carefully measured the spectral lags of individual pulses contained in
BAT/Swift gamma-ray bursts with known redshifts, and confirmed the
anti-correlation between the spectral lag and the isotropy luminosity. The
distribution of spectral lags can be well fitted by four Gaussian components,
with the centroids at 0.03 s, 0.09 s, 0.15 s, and 0.21 s, respectively. We find
that some spectral lags of the multi-peak GRBs seem to evolve with time
Helicopter simulation validation using flight data
A joint NASA/Army effort to perform a systematic ground-based piloted simulation validation assessment is described. The best available mathematical model for the subject helicopter (UH-60A Black Hawk) was programmed for real-time operation. Flight data were obtained to validate the math model, and to develop models for the pilot control strategy while performing mission-type tasks. The validated math model is to be combined with motion and visual systems to perform ground based simulation. Comparisons of the control strategy obtained in flight with that obtained on the simulator are to be used as the basis for assessing the fidelity of the results obtained in the simulator
A Bayesian spatio-temporal model of panel design data: airborne particle number concentration in Brisbane, Australia
This paper outlines a methodology for semi-parametric spatio-temporal
modelling of data which is dense in time but sparse in space, obtained from a
split panel design, the most feasible approach to covering space and time with
limited equipment. The data are hourly averaged particle number concentration
(PNC) and were collected, as part of the Ultrafine Particles from Transport
Emissions and Child Health (UPTECH) project. Two weeks of continuous
measurements were taken at each of a number of government primary schools in
the Brisbane Metropolitan Area. The monitoring equipment was taken to each
school sequentially. The school data are augmented by data from long term
monitoring stations at three locations in Brisbane, Australia.
Fitting the model helps describe the spatial and temporal variability at a
subset of the UPTECH schools and the long-term monitoring sites. The temporal
variation is modelled hierarchically with penalised random walk terms, one
common to all sites and a term accounting for the remaining temporal trend at
each site. Parameter estimates and their uncertainty are computed in a
computationally efficient approximate Bayesian inference environment, R-INLA.
The temporal part of the model explains daily and weekly cycles in PNC at the
schools, which can be used to estimate the exposure of school children to
ultrafine particles (UFPs) emitted by vehicles. At each school and long-term
monitoring site, peaks in PNC can be attributed to the morning and afternoon
rush hour traffic and new particle formation events. The spatial component of
the model describes the school to school variation in mean PNC at each school
and within each school ground. It is shown how the spatial model can be
expanded to identify spatial patterns at the city scale with the inclusion of
more spatial locations.Comment: Draft of this paper presented at ISBA 2012 as poster, part of UPTECH
projec
CENP-A Is Dispensable for Mitotic Centromere Function after Initial Centromere/Kinetochore Assembly
Human centromeres are defined by chromatin containing the histone H3 variant CENP-A assembled onto repetitive alphoid DNA sequences. By inducing rapid, complete degradation of endogenous CENP-A, we now demonstrate that once the first steps of centromere assembly have been completed in G1/S, continued CENP-A binding is not required for maintaining kinetochore attachment to centromeres or for centromere function in the next mitosis. Degradation of CENP-A prior to kinetochore assembly is found to block deposition of CENP-C and CENP-N, but not CENP-T, thereby producing defective kinetochores and failure of chromosome segregation. Without the continuing presence of CENP-A, CENP-B binding to alphoid DNA sequences becomes essential to preserve anchoring of CENP-C and the kinetochore to each centromere. Thus, there is a reciprocal interdependency of CENP-A chromatin and the underlying repetitive centromere DNA sequences bound by CENP-B in the maintenance of human chromosome segregation
Microminiaturized, biopotential conditioning system (MBCS)
Multichannel, medical monitoring system allows almost complete freedom of movement for subject during monitoring periods. System comprises monitoring unit (biobelt), transmission line, and data acquisition unit. Belt, made of polybenzimidizole fabric, is wrapped around individual's waist and held in place by overlapping sections of Velcro closure material
The polarized electron target as a new solar-neutrino detector
In this paper, we analyze the scattering of solar neutrinos on the polarized
electron target, and predict how the effect of parity violation in weak
interactions may help to distinguish neutrino signal from detector background.
We indicate that the knowledge of the Sun motion across the sky is sufficient
to predict the day/night asymmetry in the scattering on the
polarized electron target. To make this detection feasible, the polarized
electron target for solar neutrinos needs to be build from magnetic materials,
e.g. from ferromagnetic iron foils, paramagnetic scintillator crystals or
scintillating ferrofluids.Comment: 3 pages, 2 eps figures, revte
Phosphorylation of CENP-A on serine 7 does not control centromere function
CENP-A is the histone H3 variant necessary to specify the location of all eukaryotic centromeres via its CENP-A targeting domain and either one of its terminal regions. In humans, several post-translational modifications occur on CENP-A, but their role in centromere function remains controversial. One of these modifications of CENP-A, phosphorylation on serine 7, has been proposed to control centromere assembly and function. Here, using gene targeting at both endogenous CENP-A alleles and gene replacement in human cells, we demonstrate that a CENP-A variant that cannot be phosphorylated at serine 7 maintains correct CENP-C recruitment, faithful chromosome segregation and long-term cell viability. Thus, we conclude that phosphorylation of CENP-A on serine 7 is dispensable to maintain correct centromere dynamics and function
Support for graphicacy: a review of textbooks available to accounting students
This Teaching Note reports on the support available in textbooks for graphicacy that will help students understand the complexities of graphical displays. Graphical displays play a significant role in financial reporting, and studies have found evidence of measurement distortion and selection bias. To understand the complexities of graphical displays, students need a sound understanding of graphicacy and support from the textbooks available to them to develop that understanding. The Teaching Note reports on a survey that examined the textbooks available to students attending two Scottish universities. The support of critical graphicacy skills was examined in conjunction with textbook characteristics. The survey, which was not restricted to textbooks designated as required reading, examined the textbooks for content on data measurement and graphical displays. The findings highlight a lack of support for graphicacy in the textbooks selected. The study concludes that accounting educators need to scrutinize more closely the selection of textbooks and calls for more extensive research into textbooks as a pedagogic tool
High-Dose Glycine Treatment of Refractory Obsessive-Compulsive Disorder and Body Dysmorphic Disorder in a 5-Year Period
This paper describes an individual who was diagnosed with obsessive-compulsive disorder (OCD) and body dysmorphic disorder (BDD) at age 17 when education was discontinued. By age 19, he was housebound without social contacts except for parents. Adequate trials of three selective serotonin reuptake inhibitors, two with atypical neuroleptics, were ineffective. Major exacerbations following ear infections involving Group A β-hemolytic streptococcus at ages 19 and 20 led to intravenous immune globulin therapy, which was also ineffective. At age 22, another severe exacerbation followed antibiotic treatment for H. pylori. This led to a hypothesis that postulates deficient signal transduction by the N-methyl-D-aspartate receptor (NMDAR). Treatment with glycine, an NMDAR coagonist, over 5 years led to robust reduction of OCD/BDD signs and symptoms except for partial relapses during treatment cessation. Education and social life were resumed and evidence suggests improved cognition. Our findings motivate further study of glycine treatment of OCD and BDD
Measurement of the Solar Neutrino Capture Rate by the Russian-American Gallium Solar Neutrino Experiment During One Half of the 22-Year Cycle of Solar Activity
We present the results of measurements of the solar neutrino capture rate in
gallium metal by the Russian-American Gallium Experiment SAGE during slightly
more than half of a 22-year cycle of solar activity. Combined analysis of the
data of 92 runs during the 12-year period January 1990 through December 2001
gives a capture rate of solar neutrinos with energy more than 233 keV of 70.8
+5.3/-5.2 (stat.) +3.7/-3.2 (syst.) SNU. This represents only slightly more
than half of the predicted standard solar model rate of 128 SNU. We give the
results of new runs beginning in April 1998 and the results of combined
analysis of all runs since 1990 during yearly, monthly, and bimonthly periods.
Using a simple analysis of the SAGE results combined with those from all other
solar neutrino experiments, we estimate the electron neutrino pp flux that
reaches the Earth to be (4.6 +/- 1.1) E10/(cm^2-s). Assuming that neutrinos
oscillate to active flavors the pp neutrino flux emitted in the solar fusion
reaction is approximately (7.7 +/- 1.8) E10/(cm^2-s), in agreement with the
standard solar model calculation of (5.95 +/- 0.06) E10/(cm^2-s).Comment: English translation of article submitted to Russian journal Zh. Eksp.
Teor. Fiz. (JETP); 12 pages, 5 figures. V2: Added winter-summer difference
and 2 reference
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