A model for orientation effects in electron‐transfer reactions

A method for solving the single‐particle Schrödinger equation with an oblate spheroidal potential of finite depth is presented. The wave functions are then used to calculate the matrix element T_BA which appears in theories of nonadiabatic electron transfer. The results illustrate the effects of mutual orientation and separation of the two centers on TBA. Trends in these results are discussed in terms of geometrical and nodal structure effects. Analytical expressions related to T_BA for states of spherical wells are presented and used to analyze the nodal structure effects for T_BA for the spheroidal wells

Validation of the Breast Cancer Screening Beliefs Questionnaire among African Australian women

Background The Breast Cancer Screening Beliefs Questionnaire (BCSBQ) has been designed as a culturally appropriate instrument for assessing women’s beliefs, knowledge and attitudes to breast cancer and breast cancer screening practices. While it has proved to be a reliable instrument when applied to women of Chinese, Arabic and Korean origin living in Australia, its psychometric properties among women from African backgrounds have not been tested. The aim of this study is to examine the psychometric properties of the BCSBQ among African Australian women. Methods The BCSBQ was administered to 284 African Australian women who were recruited from a number of African community organizations and churches. Factor analysis was conducted to study the factor structure. Construct validity was examined using Cuzick’s non-parametric test while Cronbach alpha was used to assess internal consistency reliability. Results Exploratory factor analysis results demonstrated that the African-Australian BCSBQ can be conceptualized as a 4-factor model. The third factor, viz. “barriers to mammography”, was split into two separate factors namely, “psychological” and “practical” barriers. The results indicated that the African-Australian BCSBQ had both satisfactory validity and internal consistency. The Cronbach’s alpha of the three subscales ranged between 0.84-0.92. The frequency of breast cancer screening practices (breast awareness, clinical breast-examination and mammography) were significantly associated with attitudes towards general health check-ups and perceived barriers to mammographic screening. Conclusions Our study provided evidence to support the psychometric properties of the BCSBQ.in African Australian women. The study moreover demonstrated that the use of the instrument can help health professionals to understand the beliefs, knowledge and attitudes to breast cancer among African Australian women and also the factors that impact on their breast cancer screening practices.published_or_final_versio

A Rapid Dynamical Monte Carlo Algorithm for Glassy Systems

In this paper we present a dynamical Monte Carlo algorithm which is applicable to systems satisfying a clustering condition: during the dynamical evolution the system is mostly trapped in deep local minima (as happens in glasses, pinning problems etc.). We compare the algorithm to the usual Monte Carlo algorithm, using as an example the Bernasconi model. In this model, a straightforward implementation of the algorithm gives an improvement of several orders of magnitude in computational speed with respect to a recent, already very efficient, implementation of the algorithm of Bortz, Kalos and Lebowitz.Comment: RevTex 7 pages + 4 figures (uuencoded) appended; LPS preprin

Risk factors for human papilomavirus infection among women in Portugal: the CLEOPATRE Portugal Study

OBJECTIVE: Human papillomavirus (HPV) is responsible for a range of diseases, including cervical cancer. The primary objectives of the CLEOPATRE Portugal study were to estimate the overall and age-stratified prevalence of cervical HPV infection and to assess HPV prevalence and type-specific distribution by cytological results among women aged 18 to 64 years, who reside in mainland Portugal. MATERIALS AND METHODS: This cross-sectional population-based study recruited women aged 18 to 64 years, according to an age-stratified sampling strategy, who attended gynecology/obstetrics or sexually transmitted disease clinics across the 5 regional health administrations in mainland Portugal between 2008 and 2009. Liquid-based cytology samples were collected and analyzed centrally for HPV genotyping (clinical array HPV 2 assay) and cytology. Prevalence estimates were adjusted for age using 2007 Portuguese census data. RESULTS: A total of 2326 women were included in the study. The overall prevalence of HPV infection in the study was 19.4% (95% confidence interval, 17.8%-21.0%), with the highest prevalence in women aged 18 to 24 years. High-risk HPV types were detected in 76.5% of infections, of which 36.6% involved multiple types. The commonest high-risk type was HPV-16. At least 1 of the HPV types 6/11/16/18 was detected in 32.6% of infections. The HPV prevalence in normal cytology samples was 16.5%. There was a statistically significant association between high-risk infection and cytological abnormalities (P < 0.001). CONCLUSIONS: This is the first population-based study to quantify and describe cervical HPV infection in mainland Portugal. This study provides baseline data for future assessment of the impact of HPV vaccination programs

Negative time delay for wave reflection from a one-dimensional semi-harmonic well

It is reported that the phase time of particles which are reflected by a one-dimensional semi-harmonic well includes a time delay term which is negative for definite intervals of the incoming energy. In this interval, the absolute value of the negative time delay becomes larger as the incident energy becomes smaller. The model is a rectangular well with zero potential energy at its right and a harmonic-like interaction at its left.Comment: 6 pages, 5 eps figures. Talk presented at the XXX Workshop on Geometric Methods in Physics, Bialowieza, Poland, 201

Displacements analysis of self-excited vibrations in turning

The actual research deals with determining by a new protocol the necessary parameters considering a three-dimensional model to simulate in a realistic way the turning process on machine tool. This paper is dedicated to the experimental displacements analysis of the block tool / block workpiece with self-excited vibrations. In connexion with turning process, the self-excited vibrations domain is obtained starting from spectra of two accelerometers. The existence of a displacements plane attached to the tool edge point is revealed. This plane proves to be inclined compared to the machines tool axes. We establish that the tool tip point describes an ellipse. This ellipse is very small and can be considered as a small straight line segment for the stable cutting process (without vibrations). In unstable mode (with vibrations) the ellipse of displacements is really more visible. A difference in phase occurs between the tool tip displacements on the radial direction and on the cutting one. The feed motion direction and the cutting one are almost in phase. The values of the long and small ellipse axes (and their ratio) shows that these sizes are increasing with the feed rate value. The axis that goes through the stiffness center and the tool tip represents the maximum stiffness direction. The maximum (resp. minimum) stiffness axis of the tool is perpendicular to the large (resp. small) ellipse displacements axis. FFT analysis of the accelerometers signals allows to reach several important parameters and establish coherent correlations between tool tip displacements and the static - elastic characteristics of the machine tool components tested

Fluctuations of a holographic quantum Hall fluid

We analyze the neutral spectrum of the holographic quantum Hall fluid described by the D2-D8' model. As expected for a quantum Hall state, we find the system to be stable and gapped and that, at least over much of the parameter space, the lowest excitation mode is a magneto-roton. In addition, we find magneto-rotons in higher modes as well. We show that these magneto-rotons are direct consequences of level crossings between vector and scalar modes.Comment: 20 pages, 8 figures; v.2 figures improved, 2 figures added, and text clarified particularly in Sec. 5, to appear in JHE

Inductively guided circuits for ultracold dressed atoms

Recent progress in optics, atomic physics and material science has paved the way to study quantum effects in ultracold atomic alkali gases confined to non-trivial geometries. Multiply connected traps for cold atoms can be prepared by combining inhomogeneous distributions of DC and radio-frequency electromagnetic fields with optical fields that require complex systems for frequency control and stabilization. Here we propose a flexible and robust scheme that creates closed quasi-one-dimensional guides for ultracold atoms through the ‘dressing’ of hyperfine sublevels of the atomic ground state, where the dressing field is spatially modulated by inductive effects over a micro-engineered conducting loop. Remarkably, for commonly used atomic species (for example, 7Li and 87Rb), the guide operation relies entirely on controlling static and low-frequency fields in the regimes of radio-frequency and microwave frequencies. This novel trapping scheme can be implemented with current technology for micro-fabrication and electronic control

Investigating the biological properties of carbohydrate derived fulvic acid (CHD-FA) as a potential novel therapy for the management of oral biofilm infections.

Background: A number of oral diseases, including periodontitis, derive from microbial biofilms and are associated with increased antimicrobial resistance. Despite the widespread use of mouthwashes being used as adjunctive measures to control these biofilms, their prolonged use is not recommended due to various side effects. Therefore, alternative broad-spectrum antimicrobials that minimise these effects are highly sought after. Carbohydrate derived fulvic acid (CHD-FA) is an organic acid which has previously demonstrated to be microbiocidal against Candida albicans biofilms, therefore, the aims of this study were to evaluate the antibacterial activity of CHD-FA against orally derived biofilms and to investigate adjunctive biological effects.&lt;p&gt;&lt;/p&gt; Methods: Minimum inhibitory concentrations were evaluated for CHD-FA and chlorhexidine (CHX) against a range of oral bacteria using standardised microdilution testing for planktonic and sessile. Scanning electron microscopy was also employed to visualise changes in oral biofilms after antimicrobial treatment. Cytotoxicity of these compounds was assessed against oral epithelial cells, and the effect of CHD-FA on host inflammatory markers was assessed by measuring mRNA and protein expression.&lt;p&gt;&lt;/p&gt; Results: CHD-FA was highly active against all of the oral bacteria tested, including Porphyromonas gingivalis, with a sessile minimum inhibitory concentration of 0.5%. This concentration was shown to kill multi-species biofilms by approximately 90%, levels comparable to that of chlorhexidine (CHX). In a mammalian cell culture model, pretreatment of epithelial cells with buffered CHD-FA was shown to significantly down-regulate key inflammatory mediators, including interleukin-8 (IL-8), after stimulation with a multi-species biofilm.&lt;p&gt;&lt;/p&gt; Conclusions: Overall, CHD-FA was shown to possess broad-spectrum antibacterial activity, with a supplementary function of being able to down-regulate inflammation. These properties offer an attractive spectrum of function from a naturally derived compound, which could be used as an alternative topical treatment strategy for oral biofilm diseases. Further studies in vitro and in vivo are required to determine the precise mechanism by which CHD-FA modulates the host immune response.&lt;p&gt;&lt;/p&gt