20 research outputs found
Current status of turbulent dynamo theory: From large-scale to small-scale dynamos
Several recent advances in turbulent dynamo theory are reviewed. High
resolution simulations of small-scale and large-scale dynamo action in periodic
domains are compared with each other and contrasted with similar results at low
magnetic Prandtl numbers. It is argued that all the different cases show
similarities at intermediate length scales. On the other hand, in the presence
of helicity of the turbulence, power develops on large scales, which is not
present in non-helical small-scale turbulent dynamos. At small length scales,
differences occur in connection with the dissipation cutoff scales associated
with the respective value of the magnetic Prandtl number. These differences are
found to be independent of whether or not there is large-scale dynamo action.
However, large-scale dynamos in homogeneous systems are shown to suffer from
resistive slow-down even at intermediate length scales. The results from
simulations are connected to mean field theory and its applications. Recent
work on helicity fluxes to alleviate large-scale dynamo quenching, shear
dynamos, nonlocal effects and magnetic structures from strong density
stratification are highlighted. Several insights which arise from analytic
considerations of small-scale dynamos are discussed.Comment: 36 pages, 11 figures, Spa. Sci. Rev., submitted to the special issue
"Magnetism in the Universe" (ed. A. Balogh
Children's classics translated from English under Franco The censorship of the 'William' books and 'The adventures of Tom Sawyer'
SIGLEAvailable from British Library Document Supply Centre-DSC:DX211896 / BLDSC - British Library Document Supply CentreGBUnited Kingdo
Quality analysis of population-based information on cancer stage at diagnosis across Europe, with presentation of stage-specific cancer survival estimates: A\uc2\ua0EUROCARE-5 study
BACKGROUND:
Cancer registries (CRs) are fundamental for estimating cancer burden, evaluating screening and monitoring health service performance. Stage at diagnosis-an essential information item collected by CRs-has been made available, for the first time, by CRs participating in EUROCARE-5. We analysed the quality of this information and estimated stage-specific survival across Europe for CRs with good data quality.
DATA AND METHODS:
Sixty-two CRs sent stage (as TNM, condensed TNM or extent of disease) for 15 cancers diagnosed in 2000-2007. We assessed the quality, partly by comparing stage according to the three systems. We also developed procedures to reconstruct stage (categories: local, regional, metastatic and unknown) using information from all three systems, thus minimising the amount of missing information.
RESULTS:
Moderate-to-excellent stage concordance was found for practically all 24 CRs, for which it was possible to compare at least two staging systems. However, since stage was often incorrectly assigned, and information on the presence/absence of metastases was often lacking, data on only 7/15 cancers from 34/62 CRs (15 countries) were of sufficient quality for further analysis. Cases diagnosed 6570 years had more advanced (or lacking) stage- and worse stage-specific survival than those <70 years.
CONCLUSIONS:
Many European CRs collect and record reasonably accurate stage information. Others have difficulties. Both the completeness of primary data and the accuracy of stage coding need to be improved in order for CRs to fulfil their expanding roles in cancer control. We propose our stage reconstruction/checking procedures as a means of fully exploiting the stage information provided by EUROCARE CRs. More advanced (or lacking) stage at diagnosis plus poorer stage-specific survival in the elderly are worrying
A review of photochromism in textiles and its measurement
Photochromism is a light-induced reversible change in colour
defined as: ‘A reversible transformation in a chemical species
between two forms having different absorption spectra brought
about by photo-irradiation.’ This issue of Textile Progress provides a
review of photochromism, the different methods for producing
photochromic textiles, their properties, the measurement of kinetic
colour changes, and their application in photochromic textiles.
Photochromism can be utilised in a variety of textile products from
everyday clothing to high-technology applications such as
protective textiles, medical textiles, geo-textiles and sports textiles.
Although photochromic materials have been used since 1960 to cut
down the transmission of light through the lenses in sunglasses,
there has been limited further development since that time due to
technical difficulties not only in the application of photochromic
colourants, but also with the measurement of kinetic colourchanging properties. Renewed interest in photochromic textiles has
arisen due to improved commercial potential in particular for
applications as photochromic nanofibres, in ‘smart’ textiles and in
‘smart’ clothing
Urinary tract cancer survival in Europe 1999-2007: Results of the population-based study EUROCARE-5
Background This work presents relative survival estimates regarding urinary tract tumours among adult patients (age 65 15 years) diagnosed in Europe. It reports on survival estimates of cases diagnosed in 2000-2007, and on survival time trends from 1999-2001 to 2005-2007. Methods Data on 677,340 adult urinary tract tumour patients, (429,154 cases of invasive and non-invasive bladder and 248,186 cases of invasive kidney cancers) diagnosed between 2000 and 2007 were provided by 86 population-based cancer registries from 29 European countries. The complete approach was used to estimate survival in 2000-2007; the period approach was used to estimate survival over time. Results The age-standardised 5-year relative survival for patients with kidney tumours diagnosed in Europe during 2000-2007 was 60%. The best prognosis was observed in Southern and Central Europe and prognosis improved in all regions along the time period. For invasive and non-invasive patients with bladder tumours combined the age-standardised 5-year relative survival in Europe was 68%. The best prognosis was observed in Southern and Northern Europe. However, in Scotland and The Netherlands the relative survival was significantly lower, although the survival estimates for these two countries were based on invasive tumours only. Conclusions Differences in registration practices affect comparisons of survival values between European countries, especially in patients with urinary bladder cancers. The between-country variation in survival is influenced by the varying use of diagnostic investigation in urinary tract tumours. Further data on stage at diagnosis can help to elucidate the influence of diagnostic intensity or early diagnosis on the survival patterns