Quantum and Semiclassical Calculations of Cold Atom Collisions in Light Fields

We derive and apply an optical Bloch equation (OBE) model for describing collisions of ground and excited laser cooled alkali atoms in the presence of near-resonant light. Typically these collisions lead to loss of atoms from traps. We compare the results obtained with a quantum mechanical complex potential treatment, semiclassical Landau-Zener models with decay, and a quantum time-dependent Monte-Carlo wave packet (MCWP) calculation. We formulate the OBE method in both adiabatic and diabatic representations. We calculate the laser intensity dependence of collision probabilities and find that the adiabatic OBE results agree quantitatively with those of the MCWP calculation, and qualitatively with the semiclassical Landau-Zener model with delayed decay, but that the complex potential method or the traditional Landau-Zener model fail in the saturation limit.Comment: 21 pages, RevTex, 7 eps figures embedded using psfig, see also http://www.physics.helsinki.fi/~kasuomin

Translations of new public management: a decentred approach to school governance in four OECD countries

Despite the prevalence of corporate and performative models of school governance within and across different education systems, there are various cases of uneven, hybrid expressions of New Public Management (NPM) that reveal the contingency of global patterns of rule. Adopting a ‘decentred approach’ to governance (Bevir, M. 2010. “Rethinking Governmentality: Towards Genealogies of Governance.” European Journal of Social Theory 13 (4): 423–441), this paper compares the development of NPM in four OECD countries: Australia, England, Spain, and Switzerland. A focus of the paper is how certain policy instruments are created and sustained within highly differentiated geo-political settings and through different multi-scalar actors and authorities yet modified to reflect established traditions and practices

Ageing with HIV: medication use and risk for potential drug-drug interactions

Objectives To compare the use of co-medication, the potential drug-drug interactions (PDDIs) and the effect on antiretroviral therapy (ART) tolerability and efficacy in HIV-infected individuals according to age, ≥50 years or <50 years. Methods All ART-treated participants were prospectively included once during a follow-up visit of the Swiss HIV Cohort Study. Information on any current medication was obtained by participant self-report and medical prescription history. The complete treatment was subsequently screened for PDDIs using a customized version of the Liverpool drug interaction database. Results Drug prescriptions were analysed for 1497 HIV-infected individuals: 477 age ≥50 and 1020 age <50. Older patients were more likely to receive one or more co-medications compared with younger patients (82% versus 61%; P < 0.001) and thus had more frequent PDDIs (51% versus 35%; P < 0.001). Furthermore, older patients tended to use a higher number of co-medications and certain therapeutic drug classes more often, such as cardiovascular drugs (53% versus 19%; P < 0.001), gastrointestinal medications (10% versus 6%; P = 0.004) and hormonal agents (6% versus 3%; P = 0.04). PDDIs with ART occurred mainly with cardiovascular drugs (27%), CNS agents (22%) and methadone (6%) in older patients and with CNS agents (27%), methadone (15%) and cardiovascular drugs (11%) in younger patients. The response to ART did not differ between the two groups. Conclusions The risk for PDDIs with ART increased in older patients who take more drugs than their younger HIV-infected counterparts. However, medication use in older and younger patients did not differ in terms of effect on antiretroviral tolerability and respons

Population pharmacokinetic modelling and evaluation of different dosage regimens for darunavir and ritonavir in HIV-infected individuals

Objectives Darunavir is a protease inhibitor that is administered with low-dose ritonavir to enhance its bioavailability. It is prescribed at standard dosage regimens of 600/100 mg twice daily in treatment-experienced patients and 800/100 mg once daily in naive patients. A population pharmacokinetic approach was used to characterize the pharmacokinetics of both drugs and their interaction in a cohort of unselected patients and to compare darunavir exposure expected under alternative dosage regimens. Methods The study population included 105 HIV-infected individuals who provided darunavir and ritonavir plasma concentrations. Firstly, a population pharmacokinetic analysis for darunavir and ritonavir was conducted, with inclusion of patients' demographic, clinical and genetic characteristics as potential covariates (NONMEM®). Then, the interaction between darunavir and ritonavir was studied while incorporating levels of both drugs into different inhibitory models. Finally, model-based simulations were performed to compare trough concentrations (Cmin) between the recommended dosage regimen and alternative combinations of darunavir and ritonavir. Results A one-compartment model with first-order absorption adequately characterized darunavir and ritonavir pharmacokinetics. The between-subject variability in both compounds was important [coefficient of variation (CV%) 34% and 47% for darunavir and ritonavir clearance, respectively]. Lopinavir and ritonavir exposure (AUC) affected darunavir clearance, while body weight and darunavir AUC influenced ritonavir elimination. None of the tested genetic variants showed any influence on darunavir or ritonavir pharmacokinetics. The simulations predicted darunavir Cmin much higher than the IC50 thresholds for wild-type and protease inhibitor-resistant HIV-1 strains (55 and 550 ng/mL, respectively) under standard dosing in >98% of experienced and naive patients. Alternative regimens of darunavir/ritonavir 1200/100 or 1200/200 mg once daily also had predicted adequate Cmin (>550 ng/mL) in 84% and 93% of patients, respectively. Reduction of darunavir/ritonavir dosage to 600/50 mg twice daily led to a 23% reduction in average Cmin, still with only 3.8% of patients having concentrations below the IC50 for resistant strains. Conclusions The important variability in darunavir and ritonavir pharmacokinetics is poorly explained by clinical covariates and genetic influences. In experienced patients, treatment simplification strategies guided by drug level measurements and adherence monitoring could be propose

High specificity of line-immunoassay based algorithms for recent HIV-1 infection independent of viral subtype and stage of disease

ABSTRACT: BACKGROUND: Serologic testing algorithms for recent HIV seroconversion (STARHS) provide important information for HIV surveillance. We have shown that a patient's antibody reaction in a confirmatory line immunoassay (INNO-LIATM HIV I/II Score, Innogenetics) provides information on the duration of infection. Here, we sought to further investigate the diagnostic specificity of various Inno-Lia algorithms and to identify factors affecting it. METHODS: Plasma samples of 714 selected patients of the Swiss HIV Cohort Study infected for longer than 12 months and representing all viral clades and stages of chronic HIV-1 infection were tested blindly by Inno-Lia and classified as either incident (up to 12 m) or older infection by 24 different algorithms. Of the total, 524 patients received HAART, 308 had HIV-1 RNA below 50 copies/mL, and 620 were infected by a HIV-1 non-B clade. Using logistic regression analysis we evaluated factors that might affect the specificity of these algorithms. RESULTS: HIV-1 RNA <50 copies/mL was associated with significantly lower reactivity to all five HIV-1 antigens of the Inno-Lia and impaired specificity of most algorithms. Among 412 patients either untreated or with HIV-1 RNA ≥50 copies/mL despite HAART, the median specificity of the algorithms was 96.5% (range 92.0-100%). The only factor that significantly promoted false-incident results in this group was age, with false-incident results increasing by a few percent per additional year. HIV-1 clade, HIV-1 RNA, CD4 percentage, sex, disease stage, and testing modalities exhibited no significance. Results were similar among 190 untreated patients. CONCLUSIONS: The specificity of most Inno-Lia algorithms was high and not affected by HIV-1 variability, advanced disease and other factors promoting false-recent results in other STARHS. Specificity should be good in any group of untreated HIV-1 patients