269 research outputs found

    Trends in the incidence and survival of multiple myeloma in South East England 1985-2004.

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    BACKGROUND: Multiple myeloma is an uncommon cancer with a poor prognosis. Its incidence is expected to increase due to ageing populations and better diagnosis, and new treatments have been developed to improve survival. Our objective was to investigate trends in the epidemiology and survival of multiple myeloma for South East England. METHODS: Data on 15,010 patients diagnosed with multiple myeloma between 1985 and 2004 was extracted from the Thames Cancer Registry database. We calculated the yearly age-standardised incidence rates for males and females and age-specific incidence rates in 10-year age groups for both sexes combined. We also explored geographical variation in incidence across primary care trusts. We then used period analysis to calculate trends in 1- and 5-year relative survival over the 15 years 1990-2004, comparing survival by sex and by age group 59 years and below versus 60 years and above. Finally, we investigated 5-year relative survival for the period 2000-2004 by socio-economic deprivation, assigning patients to quintiles of deprivation using the Income Domain of the Index of Multiple Deprivation 2004 based on postcode of residence. RESULTS: The incidence of multiple myeloma was higher in males than in females and in patients over 70, throughout the period 1985-2004. No obvious geographical pattern of incidence by primary care trust emerged. The 1- and 5-year relative survival of male and female patients increased in both age groups and was statistically significant in males aged over 60. There was a tendency for better survival in patients resident in the most affluent areas, but this did not reach statistical significance. CONCLUSIONS: The trends in incidence of multiple myeloma in males and females are similar to that reported from other western populations. Relative survival was higher for younger patients although we found significant improvements in 1-year relative survival for male patients over 60 years old. The improved survival demonstrated for patients of all ages is likely to reflect increased detection, earlier diagnosis and the introduction of new treatments. Future studies should investigate the influence of ethnicity on incidence and survival, and the effect of specific treatments on survival and quality of life

    The stability of the O(N) invariant fixed point in three dimensions

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    We study the stability of the O(N) fixed point in three dimensions under perturbations of the cubic type. We address this problem in the three cases N=2,3,4N=2,3,4 by using finite size scaling techniques and high precision Monte Carlo simulations. It is well know that there is a critical value 2<Nc<42<N_c<4 below which the O(N) fixed point is stable and above which the cubic fixed point becomes the stable one. While we cannot exclude that Nc<3N_c<3, as recently claimed by Kleinert and collaborators, our analysis strongly suggests that NcN_c coincides with 3.Comment: latex file of 18 pages plus three ps figure

    Critical thermodynamics of three-dimensional MN-component field model with cubic anisotropy from higher-loop \epsilon expansion

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    The critical thermodynamics of an MNMN-component field model with cubic anisotropy relevant to the phase transitions in certain crystals with complicated ordering is studied within the four-loop \ve expansion using the minimal subtraction scheme. Investigation of the global structure of RG flows for the physically significant cases M=2, N=2 and M=2, N=3 shows that the model has an anisotropic stable fixed point with new critical exponents. The critical dimensionality of the order parameter is proved to be equal to NcC=1.445(20)N_c^C=1.445(20), that is exactly half its counterpart in the real hypercubic model.Comment: 9 pages, LaTeX, no figures. Published versio

    Confirming the existence of π-allyl-palladium intermediates during the reaction of meta photocycloadducts with palladium(ii) compounds

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    The transient existence of π-allyl-palladium intermediates formed by the reaction of Pd(OAc)2 and anisole-derived meta photocycloadducts has been demonstrated using NMR techniques. The intermediates tended to be short-lived and underwent rapid reductive elimination of palladium metal to form allylic acetates, however this degradation process could be delayed by changing the reaction solvent from acetonitrile to chloroform

    Effect of Discontinuation of Fluoride Intake from Water and Toothpaste on Urinary Excretion in Young Children

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    As there is no homeostatic mechanism for maintaining circulating fluoride (F) in the human body, the concentration may decrease and increase again when intake is interrupted and re-started. The present study prospectively evaluated this process in children exposed to F intake from water and toothpaste, using F in urine as a biomarker. Eleven children from Ibiá, Brazil (with sub-optimally fluoridated water supply) aged two to four years who regularly used fluoridated toothpaste (1,100 ppm F) took part in the study. Twenty-four-hour urine was collected at baseline (Day 0, F exposure from water and toothpaste) as well as after the interruption of fluoride intake from water and dentifrice (Days 1 to 28) (F interruption) and after fluoride intake from these sources had been re-established (Days 29 to 34) (F re-exposure). Urinary volume was measured, fluoride concentration was determined and the amount of fluoride excreted was calculated and expressed in mg F/day. Urinary fluoride excretion (UFE) during the periods of fluoride exposure, interruption and re-exposure was analyzed using the Wilcoxon test. Mean UFE was 0.25 mg F/day (SD: 0.15) at baseline, dropped to a mean of 0.14 mg F/day during F interruption (SD: 0.07; range: 0.11 to 0.17 mg F/day) and rose to 0.21 (SD: 0.09) and 0.19 (SD: 0.08) following F re-exposure. The difference between baseline UFE and the period of F interruption was statistically significant (p < 0.05), while the difference between baseline and the period of F re-exposure was non-significant (p > 0.05). The findings suggest that circulating F in the body of young children rapidly decreases in the first 24 hours and again increases very fast after discontinuation and re-exposure of F from water and toothpaste

    The stability of a cubic fixed point in three dimensions from the renormalization group

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    The global structure of the renormalization-group flows of a model with isotropic and cubic interactions is studied using the massive field theory directly in three dimensions. The four-loop expansions of the \bt-functions are calculated for arbitrary NN. The critical dimensionality Nc=2.89±0.02N_c=2.89 \pm 0.02 and the stability matrix eigenvalues estimates obtained on the basis of the generalized Padeˊ\acute{\rm e}-Borel-Leroy resummation technique are shown to be in a good agreement with those found recently by exploiting the five-loop \ve-expansions.Comment: 18 pages, LaTeX, 5 PostScript figure

    Stability of 3D Cubic Fixed Point in Two-Coupling-Constant \phi^4-Theory

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    For an anisotropic euclidean ϕ4\phi^4-theory with two interactions [u (\sum_{i=1^M {\phi}_i^2)^2+v \sum_{i=1}^M \phi_i^4] the β\beta-functions are calculated from five-loop perturbation expansions in d=4εd=4-\varepsilon dimensions, using the knowledge of the large-order behavior and Borel transformations. For ε=1\varepsilon=1, an infrared stable cubic fixed point for M3M \geq 3 is found, implying that the critical exponents in the magnetic phase transition of real crystals are of the cubic universality class. There were previous indications of the stability based either on lower-loop expansions or on less reliable Pad\'{e approximations, but only the evidence presented in this work seems to be sufficently convincing to draw this conclusion.Comment: Author Information under http://www.physik.fu-berlin.de/~kleinert/institution.html . Paper also at http://www.physik.fu-berlin.de/~kleinert/kleiner_re250/preprint.htm

    Developing the content of two behavioural interventions : using theory-based interventions to promote GP management of upper respiratory tract infection without prescribing antibiotics #1

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    Background: Evidence shows that antibiotics have limited effectiveness in the management of upper respiratory tract infection (URTI) yet GPs continue to prescribe antibiotics. Implementation research does not currently provide a strong evidence base to guide the choice of interventions to promote the uptake of such evidence-based practice by health professionals. While systematic reviews demonstrate that interventions to change clinical practice can be effective, heterogeneity between studies hinders generalisation to routine practice. Psychological models of behaviour change that have been used successfully to predict variation in behaviour in the general population can also predict the clinical behaviour of healthcare professionals. The purpose of this study was to design two theoretically-based interventions to promote the management of upper respiratory tract infection (URTI) without prescribing antibiotics. Method: Interventions were developed using a systematic, empirically informed approach in which we: selected theoretical frameworks; identified modifiable behavioural antecedents that predicted GPs intended and actual management of URTI; mapped these target antecedents on to evidence-based behaviour change techniques; and operationalised intervention components in a format suitable for delivery by postal questionnaire. Results: We identified two psychological constructs that predicted GP management of URTI: "Self-efficacy," representing belief in one's capabilities, and "Anticipated consequences," representing beliefs about the consequences of one's actions. Behavioural techniques known to be effective in changing these beliefs were used in the design of two paper-based, interactive interventions. Intervention 1 targeted self-efficacy and required GPs to consider progressively more difficult situations in a "graded task" and to develop an "action plan" of what to do when next presented with one of these situations. Intervention 2 targeted anticipated consequences and required GPs to respond to a "persuasive communication" containing a series of pictures representing the consequences of managing URTI with and without antibiotics. Conclusion: It is feasible to systematically develop theoretically-based interventions to change professional practice. Two interventions were designed that differentially target generalisable constructs predictive of GP management of URTI. Our detailed and scientific rationale for the choice and design of our interventions will provide a basis for understanding any effects identified in their evaluation. Trial registration: Clinicaltrials.gov NCT00376142This study is funded by the European Commission Research Directorate as part of a multi-partner program: Research Based Education and Quality Improvement (ReBEQI): A Framework and tools to develop effective quality improvement programs in European healthcare. (Proposal No: QLRT-2001-00657)

    Critical Behavior of the Supersolid transition in Bose-Hubbard Models

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    We study the phase transitions of interacting bosons at zero temperature between superfluid (SF) and supersolid (SS) states. The latter are characterized by simultaneous off-diagonal long-range order and broken translational symmetry. The critical phenomena is described by a long-wavelength effective action, derived on symmetry grounds and verified by explicit calculation. We consider two types of supersolid ordering: checkerboard (X) and collinear (C), which are the simplest cases arising in two dimensions on a square lattice. We find that the SF--CSS transition is in the three-dimensional XY universality class. The SF--XSS transition exhibits non-trivial new critical behavior, and appears, within a d=3ϵd=3-\epsilon expansion to be driven generically first order by fluctuations. However, within a one--loop calculation directly in d=2d=2 a strong coupling fixed point with striking ``non-Bose liquid'' behavior is found. At special isolated multi-critical points of particle-hole symmetry, the system falls into the 3d Ising universality class.Comment: RevTeX, 24 pages, 16 figures. Also available at http://www.cip.physik.tu-muenchen.de/tumphy/d/T34/Mitarbeiter/frey.htm

    Tetracritical behavior in strongly interacting theories

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    We suggest a tetracritical fixed point to naturally occur in strongly interacting theories. As a fundamental example we analyze the temperature--quark chemical potential phase diagram of QCD with fermions in the adjoint representation of the gauge group (i.e. adjoint QCD). Here we show that such a non trivial multicritical point exists and is due to the interplay between the spontaneous breaking of a global U(1) symmetry and the center group symmetry associated to confinement. Our results demonstrate that taking confinement into account is essential for understanding the critical behavior as well as the full structure of the phase diagram of adjoint QCD. This is in contrast to ordinary QCD where the center group symmetry associated to confinement is explicitly broken when the quarks are part of the theory.Comment: RevTex, 5 figures. Final version to appear in PR
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