302 research outputs found
ALGEBRAIC DIVISIBILITY SEQUENCES OVER FUNCTION FIELDS
In this note we study the existence of primes and of primitive divisors in function field analogues of classical divisibility sequences. Under various hypotheses, we prove that Lucas sequences and elliptic divisibility sequences over function fields defined over number fields contain infinitely many irreducible elements. We also prove that an elliptic divisibility sequence over a function field has only finitely many terms lacking a primitive diviso
QCD: Quantum Chromodynamic Diffraction
The first measurements of the diffractive structure function at
HERA are discussed. A factorisable interpretation in which a partonic structure
is assigned to the pomeron is investigated through QCD analyses in which both
the quark and gluon densities are permitted to vary freely. A method of
measuring the longitudinal structure function of the pomeron without changing
the centre of mass energy is presented. The possibility that the pomeron
structure may receive a large contribution from gluons, relative to quarks, at
high is highlighted, and the experimental signatures which may support
such a structure are reviewed.Comment: 8 Latex pages, 4 figures, from talks given by the authors at the
Workshop on Proton, Photon and Pomeron Structure, Durham, September 199
Exploring views on satisfaction with life in young children with chronic illness: an innovative approach to the collection of self-report data from children under 11
The objective of this study was to explore young children’s views on the impact of chronic illness on their life in order to inform future development of a patient-based self-report health outcome measure. We describe an approach to facilitating self-report views from young children with chronic illness. A board game was designed in order to obtain qualitative data from 39 children with a range of chronic illness conditions and 38 healthy controls ranging in age from 3 to 11 years. The format was effective in engaging young children in a self-report process of determining satisfaction with life and identified nine domains. The board game enabled children aged 5–11 years with chronic illness to describe the effects of living with illness on home, family, friends, school and life in general. It generated direct, non-interpreted material from children who, because of their age, may have been considered unable or limited their ability to discuss and describe how they feel. Obtaining this information for children aged 4 and under continues to be a challenge
印度尼西亚金融自由化试析
We study the 3-jet decays of S- and P-wave quarkonia with C =+. If observed, some of these will offer a way of seeing the 3G vertex of QCD via 1 S 0 , 3 P 0 , 3 P 2 (Q Q ) → GGG + Gq q → 3 jets. (As is well-known, cancellations reduce 3 P 1 ( Q Q )→ GGG .) We elaborate in detail the S-wave decay, as it is expected to show all the characteristic features of orthoquarkonium decays into 4 jets, 3 S 1 (Q Q ) → GGGG + GGq q → 4 jets, which we will comment upon. These quarkonium decays offer a very clear signal for QCD as a non-abelian local gauge field theory with color-charged gluons
Algebraic divisibility sequences over function fields
We study the existence of primes and of primitive divisors in classical
divisibility sequences defined over function fields. Under various hypotheses,
we prove that Lucas sequences and elliptic divisibility sequences over function
fields defined over number fields contain infinitely many irreducible elements.
We also prove that an elliptic divisibility sequence over a function field has
only finitely many terms lacking a primitive divisor.Comment: 28 page
Prevalence of antibodies against influenza A and B viruses in children in Germany, 2008 to 2010
The prevalence of influenza A and B virus-specific IgG was determined in sera taken between 2008 and 2010 from 1,665 children aged 0-17 years and 400 blood donors in Germany. ELISA on the basis of whole virus antigens was applied. Nearly all children aged nine years and older had antibodies against influenza A. In contrast, 40% of children aged 0-4 years did not have any influenza A virus-specific IgG antibodies. Eighty-six percent of 0-6 year-olds, 47% of 7-12 year-olds and 20% of 13-17 year-olds were serologically naive to influenza B viruses. By the age of 18 years, influenza B seroprevalence reached approximately 90%. There were obvious regional differences in the seroprevalence of influenza B in Germany. In conclusion, seroprevalences of influenza A and influenza B increase gradually during childhood. The majority of children older than eight years have basal immunity to influenza A, while comparable immunity against influenza B is only acquired at the age of 18 years. Children aged 0-6 years, showing an overall seroprevalence of 67% for influenza A and of 14% for influenza B, are especially at risk for primary infections during influenza B seasons
Severe Hepatic Trauma : Nonoperative Management, Definitive Repair, or Damage Control Surgery?
Peer reviewe
Photon-Photon and Pomeron-Pomeron Processes in Peripheral Heavy Ion Collisions
We estimate the cross sections for the production of resonances, pion pairs
and a central cluster of hadrons in peripheral heavy-ion collisions through
two-photon and double-pomeron exchange, at energies that will be available at
RHIC and LHC. The effect of the impact parameter in the diffractive reactions
is introduced, and imposing the condition for realistic peripheral collisions
we verify that in the case of very heavy ions the pomeron-pomeron contribution
is indeed smaller than the electromagnetic one. However, they give a
non-negligible background in the collision of light ions. This diffractive
background will be more important at RHIC than at LHC.Comment: 22 pages, 1 Postscript figures, 4 tables, to appear in Phys. Rev.
Varicella vaccination coverage of children under two years of age in Germany
Background: Since July 2004, routine varicella vaccination is recommended by the German Standing Vaccination Committee in Germany. Health Insurance Funds started to cover vaccination costs at different time points between 2004 and 2006 in the Federal States. Nationwide representative data on vaccination coverage against varicella of children under two years of age are not available. We aimed to determine varicella vaccination coverage in statutory health insured children under two years of age in twelve German Federal States using data from associations of statutory health insurance physicians (ASHIPs), in order to investigate the acceptance of the recommended routine varicella vaccination programme. Methods: We analysed data on varicella vaccination from 13 of 17 ASHIPs of the years 2004 to 2007. The study population consisted of all statutory health insured children under two years of age born in 2004 (cohort 2004) or 2005 (cohort 2005) in one of the studied regions. Vaccination coverage was determined by the number of children vaccinated under 2 years of age within the study population. Results: Varicella vaccination coverage of children under two years of age with either one dose of the monovalent varicella vaccine or two doses of the measles, mumps, rubella, and varicella vaccine increased from 34% (cohort 2004) to 51% (cohort 2005) in the studied regions (p < 0.001). More than half of the vaccinated children of cohort 2004 and two third of cohort 2005 were immunised at the recommended age 11 to 14 months. The level of vaccination coverage of cohort 2004 was significantly associated with the delay in introduction of cost coverage since the recommendation of varicella vaccination (p < 0.001). Conclusions: Our study shows increasing varicella vaccination coverage of young children, indicating a growing acceptance of the routine varicella vaccination programme by the parents and physicians. We recommend further monitoring of vaccination coverage using data from ASHIPs to investigate acceptance of the routine vaccination programmes over time
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