Experimental access to higher-order Zeeman effects by precision spectroscopy of highly charged ions in a Penning trap

We present an experimental concept and setup for laser-microwave double-resonance spectroscopy of highly charged ions in a Penning trap. Such spectroscopy allows a highly precise measurement of the Zeeman splittings of fine- and hyperfine-structure levels due the magnetic field of the trap. We have performed detailed calculations of the Zeeman effect in the framework of quantum electrodynamics of bound states as present in such highly charged ions. We find that apart from the linear Zeeman effect, second- and third-order Zeeman effects also contribute to the splittings on a level of 10^-4 and 10^-8, respectively, and hence are accessible to a determination within the achievable spectroscopic resolution of the ARTEMIS experiment currently in preparation

g factor of Li-like ions with nonzero nuclear spin

The fully relativistic theory of the g factor of Li-like ions with nonzero nuclear spin is considered for the (1s)^2 2s state. The magnetic-dipole hyperfine-interaction correction to the atomic g factor is calculated including the one-electron contributions as well as the interelectronic-interaction effects of order 1/Z. This correction is combined with the interelectronic-interaction, QED, nuclear recoil, and nuclear size corrections to obtain high-precision theoretical values for the g factor of Li-like ions with nonzero nuclear spin. The results can be used for a precise determination of nuclear magnetic moments from g factor experiments.Comment: 20 pages, 5 figure

Competition of fusion and quasi-fission in the reactions leading to production of the superheavy elements

The mechanism of fusion hindrance, an effect observed in the reactions of cold, warm and hot fusion leading to production of the superheavy elements, is investigated. A systematics of transfermium production cross sections is used to determine fusion probabilities. Mechanism of fusion hindrance is described as a competition of fusion and quasi-fission. Available evaporation residue cross sections in the superheavy region are reproduced satisfactorily. Analysis of the measured capture cross sections is performed and a sudden disappearance of the capture cross sections is observed at low fusion probabilities. A dependence of the fusion hindrance on the asymmetry of the projectile-target system is investigated using the available data. The most promising pathways for further experiments are suggested.Comment: 8 pages, 7 figures, talk presented at 7th International School-Seminar on Heavy-Ion Physics, May 27 - June 1, 2002, Dubna, Russi

Effects of state dependent correlations on nucleon density and momentum distributions

The proton momentum and density distributions of closed shell nuclei are calculated within a model treating short--range correlations up to first order in the cluster expansion. The validity of the model is verified by comparing the results obtained with purely scalar correlations with those produced by finite nuclei Fermi Hypernetted Chain calculations. State dependent correlations are used to calculate momentum and density distributions of 12C, 16O, 40Ca, and 48Ca, and the effects of their tensor components are studied.Comment: 16 pages, latex, 8 figures, accepted for publication in Phys. Rev.

CPT and Lorentz Tests in Penning Traps

A theoretical analysis is performed of Penning-trap experiments testing CPT and Lorentz symmetry through measurements of anomalous magnetic moments and charge-to-mass ratios. Possible CPT and Lorentz violations arising from spontaneous symmetry breaking at a fundamental level are treated in the context of a general extension of the SU(3) x SU(2) x U(1) standard model and its restriction to quantum electrodynamics. We describe signals that might appear in principle, introduce suitable figures of merit, and estimate CPT and Lorentz bounds attainable in present and future Penning-trap experiments. Experiments measuring anomaly frequencies are found to provide the sharpest tests of CPT symmetry. Bounds are attainable of approximately $10^{-20}$ in the electron-positron case and of $10^{-23}$ for a suggested experiment with protons and antiprotons. Searches for diurnal frequency variations in these experiments could also limit certain types of Lorentz violation to the level of $10^{-18}$ in the electron-positron system and others at the level of $10^{-21}$ in the proton-antiproton system. In contrast, measurements comparing cyclotron frequencies are sensitive within the present theoretical framework to different kinds of Lorentz violation that preserve CPT. Constraints could be obtained on one figure of merit in the electron-positron system at the level of $10^{-16}$, on another in the proton-antiproton system at $10^{-24}$, and on a third at $10^{-25}$ using comparisons of $H^-$ ions with antiprotons.Comment: 31 pages, published in Physical Review

Quasifission at extreme sub-barrier energies

With the quantum diffusion approach the behavior of the capture cross-section is investigated in the reactions $^{92,94}$Mo + $^{92,94}$Mo, $^{100}$Ru + $^{100}$Ru, $^{104}$Pd + $^{104}$Pd, and $^{78}$Kr + $^{112}$Sn at deep sub-barrier energies which are lower than the ground state energies of the compound nuclei. Because the capture cross section is the sum of the complete fusion and quasifission cross sections, and the complete fusion cross section is zero at these sub-barrier energies, one can study experimentally the unique quasifission process in these reactions after the capture.Comment: 3 pages, 3 figure

Trabalho infantil : uma análise das tentativas de sua erradicação no Brasil

Orientadora: Profª Drª Silvia Maria P. AraújoDissertaçao (mestrado) - Universidade Federal do Paraná, Setor de Ciencias Humanas, Letras e Artes, Programa de Pós-Graduaçao em Sociologia. Defesa: Curitiba, 22/12/2003Inclui bibliografiaResumo: Esta dissertação pretende analisar a problemática da erradicação do trabalho infantil a partir dos discursos que se produziram ao longo da história moderna, relativos às descrições de infância e dos contextos que separam o mundo adulto do mundo infantil, ou, ao retrato da construção social do que representa a infância: o mundo do trabalho como retrato do universo adulto e a educação formal (escola) como síntese da vida em formação. Os pressupostos da educação formal e do trabalho norteiam as discussões que embasam os discursos a partir dos quais, a reprodução de valores inerentes ao sistema capitalista e suas contradições, evidenciam a necessidade de se elaborar um problema social, o qual necessita de descrição, avaliação e intervenção. Ao trazer a problemática da construção do trabalho infantil como problema social, esta pesquisa pretende analisar o processo histórico da construção da problemática do trabalho infantil retratado como um problema que deve ser exterminado, segundo os discursos, tendo como base categorias trabalho e infância. Pretende ainda, compreender o contexto histórico e socioeconômico no qual o trabalho infantil passou a ser combatido como um problema social, mais precisamente no Brasil, por meio de políticas públicas, bem como, identificar no processo do que se denomina de erradicação, a garantia do controle da formação de mão-de-obra, através dos programas voltados aos jovens e às crianças pobres e vulneráveis. Por fim, esta pesquisa lança uma reflexão sobre a necessidade de participação das crianças na elaboração de documentos ou iniciativas, que garantam os direitos da infância e da adolescência e que as mesmas possam escolher dentro de suas respectivas realidades, como traçar seus destinos. A pesquisa tem como base a coleta de dados documentais que evidenciam o pressuposto de trabalho infantil como um problema social, bem como, as contradições no discurso da erradicação, contemplando documentos do PETI (Programa de Erradicação do Trabalho Infantil), do Fórum Nacional de Prevenção e Erradicação do Trabalho Infantil e do ECA (Estatuto da Criança e do Adolescente), além de participações nas reuniões do Fórum, em Curitiba, na Procuradoria Regional do Trabalho, durante o ano de 2002

The Association between Systemic Inflammatory Cellular Levels and Lung Function: A Population-Based Study

Background: Lower lung function is associated with an elevated systemic white cell count in men. However, these observations have not been demonstrated in a representative population that includes females and may be susceptible to confounding by recent airway infections or recent cigarette smoking. We tested the hypothesis that lung function is inversely associated with systemic white cell count in a population-based study. Methods: The study population consisted adults aged 17290+ years who participated in the Third National Health and Nutrition Examination Survey who did not report a recent cough, cold or acute illness in a non-smoking and smoking population. Results: In non-smoking adults with the highest quintile of the total white cell count had a FEV1 125.3 ml lower than those in the lowest quintile (95 % confidence interval CI: 2163.1 to –87.5). Adults with the highest quintile of the total white cell count had a FVC 151.1 ml lower than those in the lowest quintile (95 % confidence interval CI: 2195.0 to 2107.2). Similar associations were observed for granulocytes, mononuclear cells and lymphocytes. In current smokers, similar smaller associations observed for total white cell count, granulocytes and mononuclear cells. Conclusions: Systemic cellular inflammation levels are inversely associated with lung function in a population of both nonsmokers and smokers without acute illnesses. This may contribute to the increased mortality observed in individuals with

Human papillomavirus infection in honduran women with normal cytology

Contains fulltext : 80440.pdf (publisher's version ) (Closed access)OBJECTIVE: This study was aimed at estimating type-specific HPV prevalence and its cofactors among Honduran women with normal cytology in order to provide valuable information to health policymakers about the epidemiology of this important sexually transmitted infection. METHODS: A total of 591 women with normal cytology from Tegucigalpa, Honduras were interviewed and tested for HPV using the SPF10 LiPA25. A structured epidemiological questionnaire was administered to each woman. RESULTS: The overall HPV prevalence was 51%. Twenty-three types of HPV were detected; HPV 16, 51, 31, 18, and 11 were the most common. The highest prevalence of cancer associated HPV types (15.0%) was found in the women less than 35 years. Besides the association with age, the main independent predictors of HPV infection were the lifetime number of sexual partners and having a low socioeconomic status and less than 5 previous Pap smears. CONCLUSIONS: In the population studied, there was a broad diversity of HPV infections, with high-risk types being the most common types detected. The establishment of a well-characterized population with regard to the community prevalence of type-specific HPV infection will provide a valuable baseline for monitoring population effectiveness of an HPV vaccine

The importance of Real-Life research in Respiratory Medicine: Manifesto of the Respiratory Effectiveness Group:Endorsed by the International Primary Care Respiratory Group and the World Allergy Organization

status: publishe