367 research outputs found
Social Jetlag and Excessive Daytime Sleepiness from a Sample of Russian Children and Adolescents
PURPOSE: Insufficient nocturnal sleep is a primary source of excessive daytime sleepiness. Most previous research has focused on the disparity between sleep demands and study start times in adolescents. Fewer studies have focused on elementary schoolchildren. We hypothesize that late sleep timing is connected to excessive daytime sleepiness in a sample of Russian children and adolescents. The major goals of our study were to evaluate excessive daytime sleepiness in Russian schoolchildren and adolescents using the Russian version of the Pediatric Daytime Sleepiness Scale (PDSS) and to estimate its relationship with sleep-wake parameters using the Munich Chronotype Questionnaire (MCTQ).
MATERIALS AND METHODS: Student subjects were from public educational facilities in the Republic of Karelia. They completed both the PDSS and the Munich Chronotype Questionnaire to estimate sleep parameters and chronotype (MSFsc). Five hundred and eleven students provided data for the PDSS and sleep-wake variables, and 479 for the full MCTQ data.
RESULTS: The overall prevalence of Excessive Daytime Sleepiness (EDS) in our sample was 18%. The total PDSS score was inversely correlated with sleep length on school nights and was independent of respondents\u27 sex. Higher PDSS scores were associated with later bedtimes on school days and free days, and shorter sleep duration on school days. Late chronotype and more pronounced social jetlag were both positively correlated with high PDSS scores. A negative correlation was found between chronotype and the duration of the sleep period on weekdays (p \u3c 0.001) and a positive correlation was found on weekends (p \u3c 0.001). Longer average sleep duration was positively related to less daytime sleepiness.
CONCLUSION: This study suggests that excessive daytime sleepiness is chronotype-dependent. School start times could be shifted to a later hour to prolong sleep and reduce EDS
Energy-Saving Vibration Impulse Coal Degradation at Finely Dispersed Coal-Water Slurry Preparation
Theoretical and experimental research results of processes of finely dispersed coal-water slurry preparation for further generation of energetic gas in direct flow and vortex gas generator plants have been presented. It has been stated that frequency parameters of parabolic vibration impulse mill influence degradation degree. Pressure influence on coal parameters in grinding cavity has been proven. Experimental researches have proven efficiency of vibration impulse mill with unbalanced mass vibrator generator development. Conditions of development on intergranular walls of coal cracks have been defined
Analysis of preliminary data on reaction
We perform the analysis of the preliminary data on reaction simultaneously with the data on
scattering and reactions and
. It is found that the meson mass
MeV and .Comment: 8 pages, revtex, 3 ps files of figures, minor change
Production of scalar molecules in radiative decays
The potentialities of the production of the scalar molecules in the
radiative decays are considered beyond the narrow resonance width
approximation. It is shown that $BR(\phi\rightarrow\gamma
f_0(a_0)\rightarrow\gamma\pi\pi(\pi\eta))\approx (1\div 2)\times 10^{-5}\
,\BR(\phi\rightarrow\gamma (f_0+a_0)\rightarrow\gamma K^+K^-)\alt 10^{-6}BR(\phi\rightarrow\gamma (f_0+a_0) \to \gamma K^0\bar K^0)\alt 10^{-8}\pi\pi\ ,\ \pi\eta\ ,\ K^+K^-\ ,\ K^0\bar K^0\phi\rightarrow\gamma
f_0(a_0)e^+e^-\rightarrow\gamma \pi^+\pi^-\phi$ meson mass region.Comment: 19 pages, revtex, 4 eps files of figure
Final-state interaction phase difference in and decays
It is shown that the study of the interference pattern in the
decay provides the evidence
for the large (nearly ) relative phase between the one-photon and the
three-gluon decay amplitudes.Comment: 5 pages, revtex, \tightenlines, a version published in Phys. Rev. D
61, 117504 (2000
Search for the scalar and mesons in the reactions
It is shown that the reactions give a good
chance for observing scalar and mesons. In the photon energy region
less then 100 MeV the vector meson contributions are negligible in comparison with the scalar
mesons for
greater than
. Using two-channel treatment of the
scattering the predictions for
are derived. The four quark model, the model of molecule and
the model of scalar and mesons are discussed.Comment: 31 pages, 10 ps files of figures, minor numerical changes, Appendix
corrected, to be published in Phys.Rev.
Extending the footprint record of Pareiasauromorpha to the Cisuralian : earlier appearance and wider palaeobiogeography of the group
Pareiasauromorpha is one of the most important tetrapod groups of the Permian. Skeletal evidence suggests a late Kungurian origin in North America, whereas the majority of occurrences come from the Guadalupian and Lopingian of South Africa and Russia. However, Pareiasauromorpha footprints include the ichnogenus Pachypes, which is unknown from strata older than late Guadalupian. A revision of several Pachypes-like footprints from the Cisuralian-Guadalupian of Europe and North America confirm the occurrence of this ichnogenus and of the ichnospecies Pachypes ollieri comb. nov. beginning in the Artinskian. This is the earliest known occurrence of Pachypes and it coincides with the Artinskian reptile radiation. Based on a synapomorphy-based track-trackmaker correlation, P. ollieri can be attributed to nycteroleter pareiasauromorphs such as Macroleter. Therefore, the earliest occurrences of pareiasauromorph footprints precede by at least 10 myr the earliest occurrence of this group in the skeletal record. Moreover, the palaeobiogeography of the group is extended to the Cisuralian and Guadalupian of western Europe
New iterative methods for linear inequalities
New iterative methods for solving systems of linear inequalities are presented. Each step in these methods consists of finding the orthogonal projection of the current point onto a hyperplane corresponding to a surrogate constraint which is constructed through a positive combination of a group of violated constraints. Both sequential and parallel implementations are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45240/1/10957_2004_Article_BF00939954.pd
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