All-Order Full-Coulomb Quantum Spectral Line-Shape Calculations

Understanding how atoms interact with hot dense matter is essential for astrophysical and laboratory plasmas. Interactions in high-density plasmas broaden spectral lines, providing a rare window into interactions that govern, for example, radiation transport in stars. However, up to now, spectral line-shape theories employed at least one of three common approximations: second-order Taylor treatment of broadening operator, dipole-only interactions between atom and plasma, and classical treatment of perturbing electrons. In this Letter, we remove all three approximations simultaneously for the first time and test the importance for two applications: neutral hydrogen and highly ionized magnesium and oxygen. We found 15%-50% change in the spectral line widths, which are sufficient to impact applications including white-dwarf mass determination, stellar-opacity research, and laboratory plasma diagnostics.

Measuring the effectiveness of catch-up MMR delivered by school nurses compared to signposting to general practice on improving MMR coverage

BACKGROUND

This study assesses whether increased coverage of the measles, mumps and rubella (MMR) vaccination differs between areas where school nurses deliver catch-up MMR doses to adolescents in school settings, compared to signposting to general practice.

METHODS

A retrospective cohort study was conducted using Child Health Information Services records within the NHS England South (South Central) commissioning boundary. The sample population included children born 1 September 2000-31 August 2001, in school year 9 during the 2014-15 academic year.

RESULTS

The primary outcome findings show an increase in coverage of at least one dose of MMR by 1.6% (n = 334) in the cohort receiving catch-up MMR, compared to 0.2% (n = 12) in the cohort signposted to general practice. Over time, the difference in increase between the two cohorts was 1.4%, analysed using the chi-squared comparison of proportions test, providing strong evidence (P < 0.0001) that school nurse delivery of catch-up MMR is effective at increasing coverage. The findings also suggest that school nurse delivery of catch-up MMR may benefit Black, Asian and minority ethnic children and those from more deprived backgrounds.

CONCLUSIONS

It is recommended that commissioners of school-aged immunization services incorporate the delivery of catch-up MMR doses in their contracts with school nurses.

Coronavirus disease 2019 mortality: a multivariate ecological analysis in relation to ethnicity, population density, obesity, deprivation and pollution

BACKGROUND

There is emerging evidence about characteristics that may increase the risk of coronavirus disease 2019 (COVID-19) mortality, but they are highly correlated.

METHODS

An ecological analysis was used to estimate associations between these variables and age-standardised COVID-19 mortality rates at the local authority level.

RESULTS

Ethnicity, population density and overweight/obesity were all found to have strong independent associations with COVID-19 mortality, at the local authority level.

DISCUSSION

This analysis provides some preliminary evidence about which variables are independently associated with COVID-19 mortality and suggests that others (deprivation and pollution) are not directly linked. It highlights the importance of multivariate analyses to understand the factors that increase vulnerability to COVID-19.

Effect of Electron Capture on Spectral Line Broadening in Hot Dense Plasmas

Accurate calculation of spectral line broadening is important for many hot, dense plasma applications. However, calculated line widths have significantly underestimated measured widths for Δn=0 lines of Li-like ions, which is known as the isolated-line problem. In this Letter, scrutinization of the line-width derivation reveals that the commonly used expression neglects a potentially important contribution from electron-capture. Line-width calculations including this process are performed with two independent codes, both of which removed the discrepancies at temperatures below 10 eV. The revised calculations also suggest the remaining discrepancy scales more strongly with electron temperature than the atomic number as was previously suggested.

Recommended electron-impact excitation and ionization cross sections for Be I

Analytic fits to the recommended electron-impact excitation and ionization cross sections for Be I are presented. The lowest 19 terms of configurations 2snl (n ≤ 4) and 2p ² terms below the first ionization limit are considered. The fits are based on the accurate calculations with the convergent close coupling (CCC) method as well as the B-spline R-matrix (BSR) approach. The fitted cross sections provide rate coefficients that are believed to approximate the original data within 10% with very few exceptions. The oscillator strengths for the dipole-allowed transitions between all the considered states are calculated with the relativistic multi-configuration Dirac-Hartree-Fock (MCDHF) approach and compared with the CCC and BSR results. This comparison shows a very good agreement except for a handful of cases with likely strong cancellations.

Near-Threshold Cross Sections for Electron and Positron Impact Ionization of Atomic Hydrogen

Using classical arguments Wannier [Phys. Rev. 90, 817 (1953)PHRVAO0031-899X10.1103/PhysRev.90.817] proposed an electron-impact ionization cross section for neutral atoms to behave as E^{1.127}, where E is the excess energy above threshold. Using similar arguments Klar [J. Phys. B 14, 4165 (1981)JPAMA40022-370010.1088/0022-3700/14/21/027] obtained E^{2.65} to be the corresponding threshold law for positron impact. Recently, Babij et al. [Phys. Rev. Lett. 120, 113401 (2018)PRLTAO0031-900710.1103/PhysRevLett.120.113401] measured near-threshold positron-impact breakup behavior to be similar to that expected for electrons. Using the convergent close-coupling method for the atomic hydrogen target, we examine cross sections at near-threshold energies for electron and positron impact. Contrary to the experiment, the calculated cross sections are found to behave differently for the two projectiles and consistently with the aforementioned threshold laws, despite the entirely quantum nature of these problems. For electron impact, the threshold behavior holds while the total electron spin asymmetry remains constant, whereas for positron scattering the threshold law holds for breakup while the positronium-formation component of the ionization cross section remains constant.

A physiologically relevant 3D collagen-based scaffold-neuroblastoma cell system exhibits chemosensitivity similar to orthotopic xenograft models

3D scaffold-based in vitro cell culturing is a recent technological advancement in cancer research bridging the gap between conventional 2D culture and in vivo tumours. The main challenge in treating neuroblastoma, a paediatric cancer of the sympathetic nervous system, is to combat tumour metastasis and resistance to multiple chemotherapeutic drugs. The aim of this study was to establish a physiologically relevant 3D neuroblastoma tissue-engineered system and explore its therapeutic relevance. Two neuroblastoma cell lines, chemotherapeutic sensitive Kelly and chemotherapeutic resistant KellyCis83 were cultured in a 3D in vitro model on two collagen-based scaffolds containing either glycosaminoglycan (Coll-GAG) or nanohydroxyapatite (Coll-nHA) and compared to 2D cell culture and an orthotopic murine model. Both neuroblastoma cell lines actively infiltrated the scaffolds and proliferated displaying >100-fold increased resistance to cisplatin treatment when compared to 2D cultures, exhibiting chemosensitivity similar to orthotopic xenograft in vivo models. This model demonstrated its applicability to validate miRNA-based gene delivery. The efficacy of liposomes bearing miRNA mimics uptake and gene knockdown was similar in both 2D and 3D in vitro culturing models highlighting the proof-of-principle for the applicability of 3D collagen-based scaffolds cell system for validation of miRNA function. Collectively, this data shows the successful development and characterisation of a physiologically relevant, scaffold-based 3D tissue-engineered neuroblastoma cell model, strongly supporting its value in the evaluation of chemotherapeutics, targeted therapies and investigation of neuroblastoma pathogenesis. While neuroblastoma is the specific disease being focused upon, the platform may have multi-functionality beyond this tumour type.

STATEMENT OF SIGNIFICANCE

Traditional 2D cell cultures do not completely capture the 3D architecture of cells and extracellular matrix contributing to a gap in our understanding of mammalian biology at the tissue level and may explain some of the discrepancies between in vitro and in vivo results. Here, we demonstrated the successful development and characterisation of a physiologically relevant, scaffold-based 3D tissue-engineered neuroblastoma cell model, strongly supporting its value in the evaluation of chemotherapeutics, targeted therapies and investigation of neuroblastoma pathogenesis. The ability to test drugs in this reproducible and controllable tissue-engineered model system will help reduce the attrition rate of the drug development process and lead to more effective and tailored therapies. Importantly, such 3D cell models help to reduce and replace animals for pre-clinical research addressing the principles of the 3Rs.

Quantum suppression of antihydrogen formation in positronium-antiproton scattering

The interaction of antiprotons with low-energy positronium atoms is a fundamental three-body problem whose significance is its utility for formation of antihydrogen. Particular importance resides in understanding processes involving excited positronium states. Until recently such studies were performed using classical techniques. However, they become inapplicable in the low-energy domain. Here we report the results of comprehensive quantum calculations, which include initial excited positronium states with principal quantum numbers up to n i = 5. Contrary to expectation from earlier work, there are only muted increases in the cross-sections for antihydrogen formation for n i > 3. We interpret this in terms of quantum suppression of the reaction at higher angular momenta. Furthermore, the cross-sections for elastic scattering are around two orders of magnitude higher, which we attribute to the degeneracy of the positronium states. We outline some experimental consequences of our results.

Antiproton stopping power data for radiation therapy simulations

Stopping powers of H, He, H₂, and H₂O targets for antiprotons have been calculated using a convergent close-coupling method. For He and H₂ targets electron-electron correlations are fully accounted for using a multiconfiguration approximation. Two-electron processes are included using an independent-event model. The water molecule is described using a neon-like structure model with a pseudo-spherical potential. Results are tabulated for the purpose of Monte Carlo simulations to model antiproton transport through matter for radiation therapy.

Antihydrogen Formation via Antiproton Scattering with Excited Positronium

Utilizing the two-center convergent close-coupling method, we find a several order of magnitude enhancement in the formation of antihydrogen via antiproton scattering with positronium in an excited state over the ground state. The effect is greatest at the lowest energies considered, which encompass those achievable in experiment. This suggests a practical approach to creating neutral antimatter for testing its interaction with gravity and for spectroscopic measurements.

Target structure-induced suppression of the ionization cross section for low-energy antiproton-molecular hydrogen collisions: theoretical confirmation

Theoretical confirmation of the experimentally observed phenomenon [Knudsen et al., Phys. Rev. Lett. 105, 213201 (2010)] of target structure-induced suppression of the ionization cross section for low-energy antiproton-molecular hydrogen collisions is given. To this end a novel time-dependent convergent close-coupling approach to the scattering problem that accounts for all possible orientations of the molecular target, has been developed. The approach is applied to study single ionization of molecular hydrogen on the wide energy range from 1 keV to 2 MeV with a particular emphasis on low energies. Results for the orientation-averaged total single ionization cross section are compared with available experimental data and good agreement is found at low (<20 keV) and high (>90 keV) energies. A minor discrepancy is found within a small energy gap near the maximum of the cross section.

Ejection of quasi-free-electron pairs from the helium-atom ground state by single-photon absorption

We investigate the single-photon double ionization of helium at photon energies of 440 and 800 eV. We observe doubly charged ions with close to zero momentum corresponding to electrons emitted back to back with equal energy. These slow ions are the unique fingerprint of an elusive quasifree photon double ionization mechanism predicted by Amusia et al. nearly four decades ago [J. Phys. B 8, 1248 (1975)]. It results from the nondipole part of the electromagnetic interaction. Our experimental data are supported by calculations performed using the convergent close-coupling and time-dependent close-coupling methods.

Signature of two-electron interference in angular resolved double photoionization of Mg

The double photoionization of Mg has been studied experimentally and theoretically in a kinematic where the two photoelectrons equally share the excess energy. The observation of a symmetrized gerade amplitude, which strongly deviates from the Gaussian ansatz, is explained by a two-electron interference predicted theoretically, but never before observed experimentally. Similar to the Cooper minima in the single photoionization cross section, the effect finds its origin in the radial extent and oscillation of the target wave function.

MicroRNAs 10a and 10b are potent inducers of neuroblastoma cell differentiation through targeting of nuclear receptor corepressor 2

MicroRNAs function as negative regulators of posttranscriptional gene expression, having major roles in cellular differentiation. Several neuroblastoma cell lines can be induced to undergo differentiation by all-trans-retinoic acid (ATRA) and are used for modeling signaling pathways involved in this process. To identify miRNAs contributing to differentiation, we profiled 364 loci following ATRA treatment of neuroblastoma cell lines and found miR-10a and miR-10b to be highly overexpressed in SK-N-BE, LAN5 and SHSY-5Y. Ectopic overexpression of these miRNAs led to a major reprogramming of the transcriptome and a differentiated phenotype that was similar to that induced by ATRA in each of these cell lines. One of the predicted downregulated miR-10a/b targets was nuclear receptor corepressor 2 (NCOR2), a corepressor of gene transcription, which is known to suppress neurite outgrowth. NCOR2 was experimentally validated as a direct target of miR-10a/b, and siRNA-mediated inhibition of this mRNA alone resulted in neural cell differentiation. Moreover, induction of differentiation could be blocked by ectopic upregulation of NCOR2 using an expression construct lacking the miR-10a/b 3' untranslated region target site. We conclude that miR-10a/b has major roles in the process of neural cell differentiation through direct targeting of NCOR2, which in turn induces a cascade of primary and secondary transcriptional alterations, including the downregulation of MYCN.

Physical mechanisms and scaling laws of K-shell double photoionization

We report on the photon energy dependence of the K-shell double photoionization (DPI) of Mg, Al, and Si. The DPI cross sections were derived from high-resolution measurements of x-ray spectra following the radiative decay of the K-shell double vacancy states. Our data evince the relative importance of the final-state electron-electron interaction to the DPI. By comparing the double-to-single K-shell photoionization cross-section ratios for neutral atoms with convergent close-coupling calculations for He-like ions, the effect of outer shell electrons on the K-shell DPI process is assessed. Universal scaling of the DPI cross sections with the effective nuclear charge for neutral atoms is revealed.

Coulomb breakup problem

We formulate scattering theory in the framework of a surface-integral approach utilizing analytically known asymptotic forms of the three-body wave functions. This formulation is valid for both short-range and Coulombic potentials. The post and prior forms of the breakup amplitude are derived without any reference to renormalization procedures.

The operational emergency department attendance register (OPEDAR): a new epidemiological tool

AIM

To determine the number, status and nature of emergency department attendances to deployed field hospitals.

POPULATION

All attendances to the emergency department (ED) of deployed field hospitals in support of Operation TELIC (Iraq) from initial entry war fighting to enduring operations.

METHODS

Analysis of hand written and electronic registers ED attendance registers and validation with four other data sources.

RESULTS

Validation of data held on OpEDAR against 4 other data sources shows that OpEDAR is accurate, but that accuracy can be further improved. 26,746 ED attendances recorded on OP TELIC from 19 March 2003 to 11 November 2006. 21,112 (78.9%) were UK military. Overall, 43.5% were admitted from ED. Attendances peaked during TELIC phases 2 (422.9 per 1,000 troops deployed), but have settled to around 200 per 1,000 troops deployed in the more recent phases. Ophthalmology rates peaked in TELIC 2 to 20.72 per 1,000 and have since reduced to a consistent 10 to 15 per 1,000. This suggests that preventative measures introduced for eye injury are incompletely effective or incompletely utilised.

CONCLUSIONS

OpEDAR is a clinical tool to inform manning, equipment and training requirements for enduring and new operations, focused on the requirements of the emergency department. Multivariate quality control models applied in industry could be applied to OpEDAR to produce a dynamic epidemiological tool that identifies emerging case clusters and facilitates deployed commanders to take preventative action.

Near-threshold positron-impact ionization of atomic hydrogen

We consider the positron-impact ionization (breakup) of atomic hydrogen utilizing the full and S-wave model calculations, concentrating on the near-threshold energy region. Unlike the corresponding electron-impact case, the S-wave model does support the Wannier-like threshold law predicted by Ihra et al. [Phys. Rev. Lett. 78, 4027 (1997)10.1103/PhysRevLett.78.4027]. It is found that convergent S-wave model cross sections are obtained only if complete expansions are utilized on both the atomic and the positronium centers. Furthermore, we suggest that, in the model and full calculations, the separate contributions to the breakup cross section from both centers become equal at threshold.

Partial photoionization cross sections and angular distributions for double excitation of helium up to the N = 13 threshold

Partial photoionization cross sections sigmaN(Egamma) and photoelectron angular distributions betaN(Egamma) were measured for the final ionic states He+ (N > 4) in the region between the N = 8 and N = 13 thresholds (Egamma > 78.155 eV) using the cold target recoil ion momentum spectroscopy technique (COLTRIMS). Comparison of the experimental data with two independent sets of theoretical predictions reveals disagreement for the branching ratios to the various HeN(+) states. The angular distributions just below the double ionization threshold suggest an excitation process for highly excited N states similar to the Wannier mechanism for double ionization.

Bayesian projections: what are the effects of excluding data from younger age groups?

Bayesian age-period-cohort models are used increasingly to project cancer incidence and mortality rates. Data for younger age groups for which rates are low are often discarded from the analysis. The authors explored the effect of excluding these data, in terms of the precision and accuracy of projections, for selected cancer mortality data sets. Projections were made by using a generalized Bayesian age-period-cohort model. Smoothing was applied to each time scale to reduce random variation between adjacent parameter estimates. The sum of squared standardized residuals was used to assess the accuracy of projections, and 90% credible intervals were calculated to assess precision. For the data sets considered, inclusion of all age groups in the analysis provided more precise age-standardized and age-specific projections as well as more accurate age-specific projections for younger age groups. An overall improvement in the accuracy of age-standardized rates was demonstrated for males but not females, which may suggest that analysis of the full data set is beneficial when projecting cancer rates with strong cohort effects.

The epidemiology of multiple sclerosis in Devon: a comparison of the new and old classification criteria

OBJECTIVES

To determine the prevalence of multiple sclerosis in Devon and compare the new McDonald classification guidelines with the Poser criteria currently used.

METHODS

All patients known to have multiple sclerosis and alive and resident within the chosen area on 1 June 2001 were included in the study. Seven sources of case ascertainment were used and each patient was classified according to both the Poser criteria and the McDonald guidelines.

RESULTS

The prevalence of multiple sclerosis in Devon was 118 per 100,000 (definite and probable cases, Poser criteria) in a population of 341,796, on the prevalence day. The prevalence of definite and possible cases, as classified by the new McDonald guidelines, was slightly lower at 117 per 100,000. Clinical demographics of the prevalent population were similar to those of other studies in the United Kingdom.

CONCLUSIONS

This is first survey to use the new recommended guidelines and compare these criteria with the Poser classification. The difficulties encountered with applying the new criteria in research are highlighted, as are the differences between the new and old criteria. This study reports one of the highest prevalences in the south of the UK, adding support for a north-south divide being a step effect rather than a latitudinal gradient.

Integral representation for the electron-atom ionization amplitude which is free of ambiguity and divergence problems

It is shown that existing problems with the formal theory of ionization can be effectively resolved. An integral representation for the ionization amplitude free of ambiguity and divergence problems is given. Moreover, the ionization amplitude in the new formulation is shown directly to have an ideal form for practical calculations.

Mechanisms of photo double ionization of helium by 530 eV photons

We have measured fully differential cross sections for photo double ionization of helium 450 eV above the threshold. We have found an extremely asymmetric energy sharing between the photoelectrons and an angular asymmetry parameter beta approximately 2 and beta approximately 0 for the fast and slow electrons, respectively. The electron angular distributions show a dominance of the shakeoff for 2 eV electrons and clear evidence of an inelastic electron-electron scattering at an electron energy of 30 eV. The data are in excellent agreement with convergent close-coupling calculations.

Recent trends and future directions for lung cancer mortality in Europe

Lung cancer mortality patterns throughout Europe are very heterogeneous and largely reflect past smoking habits. In order to clarify the changing patterns of lung cancer in Europe we have plotted the overall lung cancer trends among men and women for 20 countries from 1950 up to 1998. Furthermore, using a Bayesian age-period-cohort approach, we have calculated 5 year projections of lung cancer rate up to 2003. Finally, we make some comments on probable future trends by analysing recent trends in adults aged <55 years. Lung cancer mortality rates up to age 75 years portray a general trend of decreasing lung cancer rates among men and increasing lung cancer rates among women. Exceptions to this decrease among men include Hungary where not only are current mortality rates much higher than previously observed in any other country (at 76.7 out of 100,000 in 1998) but they are projected to increase further in the short term. Rates among adults aged <55 years have recently peaked, indicating that overall rates are likely to peak in the next decade. Among women, rapid increases have been observed in Denmark, Netherlands, Hungary, Ireland and UK. Whereas Ireland and UK rates have started to decrease and are projected to continue falling, rates in the other three countries are projected to increase further. Trends in women aged <55 years indicate that rates in Danish women will peak in the next decade, whereas lung cancer rates among Dutch women are likely to continue increasing. Rates in Hungarian women are likely to increase and will surpass the current high rate observed in Denmark.

Benchmark nonperturbative calculations for the electron-impact ionization of Li(2s) and Li(2p)

Three independent nonperturbative calculations are reported for the electron-impact ionization of both the ground and first excited states of the neutral lithium atom. The time-dependent close-coupling, the R matrix with pseudostates, and the converged close-coupling methods yield total integral cross sections that are in very good agreement with each other, while perturbative distorted-wave calculations yield cross sections that are substantially higher. These nonperturbative calculations provide a benchmark for the continued development of electron-atom experimental methods designed to measure both ground and excited state ionization.

Recent trends and future projections of lymphoid neoplasms--a Bayesian age-period-cohort analysis

OBJECTIVES

A steady increase in incidence of lymphoid neoplasms has been reported, especially for non-Hodgkin's lymphoma (NHL). Using high-quality incidence data from 1973-1992 in nine population-based cancer registries (Alberta, Bombay, Denmark, Israel, New Zealand, Osaka, Oxford, Slovenia, Utah), we have examined past increases in specific lymphoid neoplasms. Further, by using a Bayesian age-period-cohort approach, we have calculated 5-, 10- and 15-year projections for each group of lymphoid neoplasms.

RESULTS

NHL incidence increased in all centers by an average of 77% in men and 66% in women between 1973 and 1992. Fifteen-year projections of these rates to 2003-2007 indicate that they will increase by an average of 55% among men and 79% among women. High projected incidence rates above 15/100,000 in men and 10/100,000 in women are expected in Alberta, Denmark, Israel, New Zealand, Oxford, and Utah by 2003-2007. The one notable exception was among men from Osaka, where no increase was projected. Modest increases in leukemia and multiple myeloma rates were observed in most of the nine registries with further projected increases by 2007. Projected incidence rates of Hodgkin's disease indicated little change.

CONCLUSION

Increases in NHL rates are occurring worldwide and provide no evidence of peaking. A key assumption in the projected rates is that the effect of environmental agents determining the trends during 1973-1992 will remain stable during the subsequent projection period.

Estimating birth prevalence of Down's syndrome

BACKGROUND

Estimates of maternal age-specific prevalence of Down's syndrome are needed for the assessment of environmental factors, for counselling and monitoring screening programmes. The estimates should relate to populations of women who have not received prenatal screening. This is normally achieved by using data collected before the widespread use of screening. The problem of under-ascertainment in some data-sets has been recognised in the literature, but has not been dealt with satisfactorily in the statistical models used to estimate live-birth prevalence.

METHODS

In this paper we develop a model that takes explicit account of under-ascertainment and apply this model to data from nine published studies. The primary aim of our analysis is to provide an improved model for live-birth prevalence. A secondary aim is to examine the ascertainment rates in the nine studies.

RESULTS

The proposed model provides a good fit to all but one of the nine studies, although exclusion of this study does not affect the estimated risks. The estimate of risk weighted across the maternal age distribution is 1.41 in 1000 live-births [90% confidence interval (CI) 1.37-1.49].

DISCUSSION

Comparing this figure with those obtained from published rate schedules suggests that the proposed model predicts rates that are some 10% higher than those obtained when ascertainment is assumed to be complete in all studies. The predicted rates are similar to those calculated when only those studies known to have high levels of acertainment are included.

Empirical Bayes adjustments for multiple results in hypothesis-generating or surveillance studies

Traditional methods of adjustment for multiple comparisons (e.g., Bonferroni adjustments) have fallen into disuse in epidemiological studies. However, alternative kinds of adjustment for data with multiple comparisons may sometimes be advisable. When a large number of comparisons are made, and when there is a high cost to investigating false positive leads, empirical or semi-Bayes adjustments may help in the selection of the most promising leads. Here we offer an example of such adjustments in a large surveillance data set of occupation and cancer in Nordic countries, in which we used empirical Bayes (EB) adjustments to evaluate standardized incidence ratios (SIRs) for cancer and occupation among craftsmen and laborers. For men, there were 642 SIRs, of which 138 (21%) had a P < 0.05 (13% positive with SIR > 1.0 and 8% negative with SIR < or = 1.0) when testing the null hypothesis of no cancer/occupation association; some of these were probably due to confounding by nonoccupational risk factors (e.g., smoking). After EB adjustments, there were 95 (15%) SIRs with P < 0.05 (10% positive and 5% negative). For women, there were 373 SIRs, of which 37 (10%) had P < 0.05 before adjustment (6% positive and 4% negative) and 13 (3%) had P < 0.05 after adjustment (2% positive and 1% negative). Several known associations were confirmed after EB adjustment (e.g., pleural cancer among plumbers, original SIR 3.2 (95% confidence interval, 2.5-4.1), adjusted SIR 2.0 (95% confidence interval, 1.6-2.4). EB can produce more accurate estimates of relative risk by shrinking imprecise outliers toward the mean, which may reduce the number of false positives otherwise flagged for further investigation. For example, liver cancer among chimney sweepers was reduced from an original SIR of 2.2 (range, 1.1-4.4) to an adjusted SIR of 1.1 (range, 0.9-1.4). A potentially important future application for EB is studies of gene-environment-disease interactions, in which hundreds of polymorphisms may be evaluated with dozens of environmental risk factors in large cohort studies, producing thousands of associations.

Projections of alcohol- and tobacco-related cancer mortality in Central Europe

Central European mortality rates for cancer sites related to tobacco and alcohol have increased rapidly in recent decades. From a public health point of view, it is of considerable interest to know whether these past increases in cancer mortality will continue into the future. Cancer mortality rates for the period 1965-1994 in Bulgaria, Czech Republic and Slovakia (analysed together), Hungary, Poland, and Romania were analysed for cancers of the larynx, oral cavity and pharynx, oesophagus, bladder, kidney, and pancreas. Using a Bayesian age-period-cohort approach, we have calculated smoothed observed rates. The effects of period and cohort were extrapolated to estimate mortality projections for 1995-99, 2004-09, and 2005-09. Mortality rates for all sites are projected to increase in most countries. Hungary has the highest projected rates for most sites, and particularly rapid increases are expected for cancers of the oral cavity and pharynx and of the larynx in Hungarian men. The smoothed 1990-94 male mortality rates for these two sites of 16. 32/100,000 and 8.70/100,000, respectively, are projected to reach 35. 17/100,000 for cancer of the oral cavity and pharynx and 14.12/100, 000 for cancer of the larynx by the period 2000-04. For kidney cancer, former Czechoslovakia has the highest observed and projected mortality rates. The smoothed 1990-94 rate of 8.37/100,000 is expected to increase 24% to 10.38/100,000 by 2000-04. Our results indicate that further increases may be expected on top of the already high cancer mortality levels in Central Europe. Policies to reduce alcohol consumption and prevent smoking in younger generations are necessary to reduce mortality as these cohorts age.

Joint estimation of Down syndrome risk and ascertainment rates: a meta-analysis of nine published data sets

In this paper we present an analysis of nine data sets in which ascertainment and maternal age risk of Down syndrome are estimated jointly using maximum likelihood. We include data on 4825 Down syndrome cases from nine previously published data sets. These include data from studies carried out before the introduction of prenatal screening and from recent studies involving women who had not received prenatal testing. Our results show that, allowing for under-ascertainment, there is a good degree of consistency between the different data sets. We compare the three- and five-parameter constant plus exponential model with a three-parameter logistic model for maternal age-specific risk. We show that the three-parameter logistic model provides a good fit to the data and compare rates from this model with those derived from published studies of uncertain completeness (Cuckle et al., 1987) and those from data sets believed to be complete (Halliday et al., 1995; Hecht and Hook, 1994, 1996). In general, our results agree closely with those of the latter, but achieve greater precision because of the inclusion of additional data. Our derived rates are considerably higher than those of Cuckle et al. (1987), which are embedded in many computer systems for generating risks.