Competitive partitioning of rotational energy in gas ensemble equilibration

A wide-ranging computational study of equilibration in binary mixtures of diatomic gases reveals the existence of competition between the constituent species for the orbital angular momentum and energy available on collision with the bath gas. The ensembles consist of a bath gas AB(v;j), and a highly excited minor component CD(v';j'), present in the ratio AB:CD = 10:1. Each ensemble contains 8000 molecules. Rotational temperatures (T(r)) are found to differ widely at equilibration with T(r)(AB)/T(r)(CD) varying from 2.74 to 0.92, indicating unequal partitioning of rotational energy and angular momentum between the two species. Unusually, low values of T(r) are found generally to be associated with diatomics of low reduced mass. To test effects of the equi-partition theorem on low T(r) we undertook calculations on HF(6;4) in N(2)(0;10) over the range 100-2000 K. No significant change in T(r)(N2)/T(r)(HF) was found. Two potential sources of rotational inequality are examined in detail. The first is possible asymmetry of -Δj and +Δj probabilities for molecules in mid- to high j states resulting from the quadratic dependence of rotational energy on j. The second is the efficiency of conversion of orbital angular momentum, generated on collision with bath gas molecules, into molecular rotation. Comparison of these two possible effects with computed T(r)(AB)/T(r)(CD) shows the efficiency factor to be an excellent predictor of partitioning between the two species. Our finding that T(r) values for molecules such as HF and OH are considerably lower than other modal temperatures suggests that the determination of gas ensemble temperatures from Boltzmann fits to rotational distributions of diatomics of low reduced mass may require a degree of caution

Primary goals, information-giving and men\u27s understanding: A qualitative study of Australian and UK doctors\u27 varied communication about PSA screening

Objectives: (1) To characterise variation in general practitioners’ (GPs’) accounts of communicating with men about prostate cancer screening using the prostate-specific antigen (PSA) test, (2) to characterise GPs’ reasons for communicating as they do and (3) to explain why and under what conditions GP communication approaches vary. Study design and setting: A grounded theory study. We interviewed 69 GPs consulting in primary care practices in Australia (n=40) and the UK (n=29). Results: GPs explained their communication practices in relation to their primary goals. In Australia, three different communication goals were reported: to encourage asymptomatic men to either have a PSA test, or not test, or alternatively, to support men to make their own decision. As well as having different primary goals, GPs aimed to provide different information (from comprehensive to strongly filtered) and to support men to develop different kinds of understanding, from population-level to ‘gist’ understanding. Taking into account these three dimensions (goals, information, understanding) and building on Entwistle et al’s Consider an Offer framework, we derived four overarching approaches to communication: Be screened, Do not be screened, Analyse and choose, and As you wish. We also describe ways in which situational and relational factors influenced GPs’ preferred communication approach. Conclusion: GPs’ reported approach to communicating about prostate cancer screening varies according to three dimensions—their primary goal, information provision preference and understanding sought—and in response to specific practice situations. If GP communication about PSA screening is to become more standardized in Australia, it is likely that each of these dimensions will require attention in policy and practice support interventions

Testing positive for human papillomavirus in routine cervical screening: examination of psychosocial impact

Objective To examine the psychosocial impact of testing positive for high risk human papillomavirus (HPV) among women attending primary cervical screening.Design Cross sectional survey.Measures were taken at baseline and one week after the receipt of HPV and cytology screening results.Setting Well women's clinic in London, UK.Population or Sample Four hundred and twenty-eight women aged 20-64 years.Methods Postal questionnaire survey.Main outcome measures Psychosocial and psychosexual outcomes were anxiety, distress and feelings about current, past and future sexual relationships.Results Women with normal cytology who tested positive for HPV (HPVdivided by) were significantly more anxious and distressed than women who were negative (HPV-) using both a state anxiety measure [F(1,267)=29, P<0.0001] and a screening specific measure of psychological distress [F(1,267)=69, P<0.0001]. Women with an abnormal or unsatisfactory smear result, who tested HPV,. were significantly more distressed than HPV- women with the same smear result [F(1,267)=8.8, P=0.002], but there was no significant difference in state anxiety. Irrespective of cytology result, HPV women reported feeling significantly worse about their sexual relationships. Approximately one-third of women who tested positive reported feeling worse about past and future sexual relationships compared with less than 2% of HPV- women.Conclusion The findings suggest that testing positive for HPV may have an adverse psychosocial impact, with increased anxiety., distress and concern about sexual relationships. Psychosocial outcomes of HPV testing need further investigation and must be considered alongside clinical and economic decisions to include HPV testing in routine cervical screening

Shared decision-making about cardiovascular disease medication in older people: A qualitative study of patient experiences in general practice

Objectives To explore older people's perspectives and experiences with shared decision-making (SDM) about medication for cardiovascular disease (CVD) prevention. Design, setting and participants Semi-structured interviews with 30 general practice patients aged 75 years and older in New South Wales, Australia, who had elevated CVD risk factors (blood pressure, cholesterol) or had received CVD-related lifestyle advice. Data were analysed by multiple researchers using Framework analysis. Results Twenty eight participants out of 30 were on CVD prevention medication, half with established CVD. We outlined patient experiences using the four steps of the SDM process, identifying key barriers and challenges: Step 1. Choice awareness: taking medication for CVD prevention was generally not recognised as a decision requiring patient input; Step 2. Discuss benefits/harms options: CVD prevention poorly understood with emphasis on benefits; Step 3. Explore preferences: goals, values and preferences (eg, length of life vs quality of life, reducing disease burden vs risk reduction) varied widely but generally not discussed with the general practitioner; Step 4. Making the decision: overall preference for directive approach, but some patients wanted more active involvement. Themes were similar across primary and secondary CVD prevention, different levels of self-reported health and people on and off medication. Conclusions Results demonstrate how older participants vary widely in their health goals and preferences for treatment outcomes, suggesting that CVD prevention decisions are preference sensitive. Combined with the fact that the vast majority of participants were taking medications, and few understood the aims and potential benefits and harms of CVD prevention, it seems that older patients are not always making an informed decision. Our findings highlight potentially modifiable barriers to greater participation of older people in SDM about CVD prevention medication and prevention in general

On the measurement of molecular anisotropies using laser techniques. II. Differential absorption of circularly and linearly polarized light

In this paper we describe a method which yields an unambiguous measure of the state multipolar moments of an anisotropic array of the angular momentum components of an assembly of ground state molecules. The method involves the measurement of circularly and linearly dichroic, single photon absorption and through such measurements, state moments having AT≤2 may be directly obtained. The advantages of this technique over polarized laser fluorescence are discussed

On the measurement of molecular anisotropies using laser techniques. III. Detection of the higher multipoles

In this paper we discuss the problem of measuring the higher moments (K≥2) of a generalized anisotropic distribution of molecular rotors. Two photon absorption techniques may be used to obtain these quantities and the appropriate expressions for linear and circular dichroism are derived

On the measurement of molecular anisotropies using laser techniques. I. Polarized laser fluorescence

The tensor density matrix formalism is used to derive expressions for the circular and linear polarization of laser‐induced fluorescence from molecules which have an anisotropic distribution in the spatial orientation of their ground state angular momentum components. The generalized anisotropic distribution is expressed as a series of state multipolar moments and it is shown that the excited state multipolar moments created therefrom by the absorption of laser radiation may be quite complex even in the absence of perturbations which cause cross relaxation. Under these circumstances, polarized laser fluorescence does not give an unambiguous measure of the ground state multipolar moments and in succeeding papers we discuss methods which do yield these quantities without ambiguity