36 research outputs found
Synthetic Spectrum Constraints on a Model of the Cataclysmic Variable QU Carinae
Neither standard model SEDs nor truncated standard model SEDs fit observed
spectra of QU Carinae with acceptable accuracy over the range 900\AA to
3000\AA. Non-standard model SEDs fit the observation set accurately. The
non-standard accretion disk models have a hot region extending from the white
dwarf to ,a narrow intermediate temperature annulus, and an
isothermal remainder to the tidal cutoff boundary. The models include a range
of values between and
and limiting values of
between and . A solution with is consistent with an empirical mass-period relation. The set
of models agree on a limited range of possible isothermal region
values between 14,000K and 18,000K. The model-to-model residuals are so similar
that it is not possible to choose a best model. The Hipparcos distance, 610 pc,
is representative of the model results. The orbital inclination is between
40\arcdeg and 60\arcdeg.Comment: 52 pages, 19 Figure
Diffractive Dijet Production at s = 630 and 1800 GeV at the Fermilab Tevatron
We report a measurement of the diffractive structure function F-jj(D) of the antiproton obtained from a study of dijet events produced in association with a leading antiproton in (p) over barp collisions at roots = 630 GeV at the Fermilab Tevatron. The ratio of F-jj(D) at roots = 630 GeV to F-jj(D) obtained from a similar measurement at roots = 1800 GeV is compared with expectations from QCD factorization and other theoretical predictions. We also report a measurement of the xi (x-Pomeron) and beta (x of parton in Pomeron) dependence of F-jj(D) at roots = 1800 GeV . In the region 0.035 < ξ < 0.095 , \t\ < 1 GeV2 , and β < 0.5 , F-jj(D)(beta, xi) is found to be of the form beta(-1.0+/-0.1) xi(-0.9+/-0. 1) , which obeys beta-xi factorization
Measurement of the Ratio of b Quark Production Cross Sections in Antiproton-Proton Collisions at 630 GeV and 1800 GeV
We report a measurement of the ratio of the bottom quark production cross
section in antiproton-proton collisions at 630 GeV to 1800 GeV using bottom
quarks with transverse momenta greater than 10.75 GeV identified through their
semileptonic decays and long lifetimes. The measured ratio
sigma(630)/sigma(1800) = 0.171 +/- .024 +/- .012 is in good agreement with
next-to-leading order (NLO) quantum chromodynamics (QCD)
Psychoemotional Status of Schoolchildren before and during Distance Learning at the Time of 2020 Coronavirus Lockdown
Introduction: During lockdown, a student is influenced by a combination of external factors including family environment, increased social and emotional stress, higher educational and computer load, and higher responsibility for doing homework, which inevitably changes his psychoemotional sphere and coping behavior. In order to study characteristics of psychoemotional and behavioral reactions of schoolchildren before and during 2020 COVID-19 lockdown, we conducted a questionnaire-based survey of 1,160 fifth to eleventh graders aged 11–18 in the city of Chelyabinsk. Results: We established a high level of reactive anxiety in 7.9 % and 9.9 % and a low level in 63.4 % and 59.4 % of schoolchildren before and during lockdown, respectively. A high level of personal anxiety was observed in 33.6 % and 42.6 % of children and a low level – in 19.8 % and 16.8 % of schoolchildren before and during lockdown, respectively. Higher levels of reactive and personal anxiety were more prevalent in girls than in boys. We noted a high and increased levels of aggression in 78.6 % and 80.5 % and very high and high levels of neuroticism in 44.6 % and 44.4 % of the respondents before and during school closure, respectively. A high level of emotional excitability and neurotization was observed in one third of the surveyed schoolchildren. The number of respondents with a high level of neurotization and emotional excitability rose by 7.5 % and 4.0 % during lockdown, respectively. The proportion of successful distance learning schoolchildren increased by 16.8 %. Conclusions: Lockdown contributed to the increase in the levels of anxiety, aggressiveness, and neuroticism in school-age adolescents. The number of respondents complaining of sleep disturbance, visual impairment and headaches became 2.7, 1.1, and 1.1 times higher during lockdown. We revealed significant differences in sleep disorders, headaches, dizziness, complaints of vision impairment, fatigue, and irritability between successful and unsuccessful schoolchildren (p < 0.05).</jats:p
