Tsunami generation by ocean floor rupture front propagation: Hamiltonian description

The Hamiltonian method is applied to the problem of tsunami generation caused by a propagating rupture front and deformation of the ocean floor. The method establishes an alternative framework for analyzing the tsunami generation process and produces analytical expressions for the power and directivity of tsunami radiation (in the far-field) for two illustrative cases, with constant and gradually varying speeds of rupture front propagation

Tension, rigidity and preferential curvature of interfaces between coexisting polymer solutions

The properties of the interface in a phase-separated solution of polymers with different degrees of polymerization and Kuhn segment lengths are calculated. The starting point is the planar interface, the profile of which is calculated in the so-called 'blob model', which incorporates the solvent in an implicit way. The next step is the study of a metastable droplet phase formed by imposing a chemical potential different from that at coexistence. The pressure difference across the curved interface, which corresponds to this higher chemical potential, is used to calculate the curvature properties of the droplet. Interfacial tensions, Tolman lengths and rigidities are calculated and used for predictions for a realistic experimental case. The results suggest that interfaces between phase-separated solutions of polymers exhibit, in general, a preferential curvature, which stabilizes droplets of low molecular mass polymer in a high molecular mass macroscopic phase.Comment: 21 pages; 8 figures; accepted for publication in Macromolecule

Kondo Behavior of U in CaB6_6

Replacing U for Ca in semiconducting CaB$_6$ at the few at.% level induces metallic behaviour and Kondo-type phenomena at low temperatures, a rather unusual feature for U impurities in metallic hosts. For Ca$_{0.992}$U$_{0.008}$B$_6$, the resistance minimum occurs at $T$ = 17 K. The subsequent characteristic logarithmic increase of the resistivity with decreasing temperature merges into the expected $T^2$ dependence below 0.8 K. Data of the low-temperature specific heat and the magnetization are analyzed by employing a simple resonance-level model. Analogous measurements on LaB$_6$ with a small amount of U revealed no traces of Kondo behavior, above 0.4 K.Comment: 4 pages, 4 figures, submitted for publication to Europhysics Letter

Equity in utilization of antiretroviral therapy for HIV-infected people in South Africa: a systematic review

INTRODUCTION: About half a million people in South Africa are deprived of antiretroviral therapy (ART), and there is little systematic knowledge on who they are – e.g. by severity of disease, sex, or socio-economic status (SES). We performed a systematic review to determine the current quantitative evidence-base on equity in utilization of ART among HIV-infected people in South Africa. METHOD: We conducted a literature search based on the Cochrane guidelines. A study was included if it compared for different groups of HIV infected people (by sex, age, severity of disease, area of living, SES, marital status, ethnicity, religion and/or sexual orientation (i.e. equity criteria)) the number initiating/adhering to ART with the number who did not. We considered ART utilization inequitable for a certain criterion (e.g. sex) if between groups (e.g. men versus women) significant differences were reported in ART initiation/adherence. RESULTS: Twelve studies met the inclusion criteria. For sex, 2 out of 10 studies that investigated this criterion found that men are less likely than women to utilize ART, while the other 8 found no differences. For age, 4 out of 8 studies found inequities and reported less utilization for younger people. For area of living, 3 out of 4 studies showed that those living in rural areas or certain provinces have less access and 2 out of 6 studies looking at SES found that people with lower SES have less access. One study which looked at the marital status found that those who are married are less likely to utilize ART. For severity of disease, 5 out of 6 studies used more than one outcome measure for disease stage and reported within their study contradicting results. One of the studies reported inconclusive findings for ethnicity and no study had looked at religion and sexual orientation. CONCLUSION: It seems that men, young people, those living in certain provinces or rural areas, people who are unemployed or with a low educational level, and those being unmarried have less access to ART. As studies stem from different contexts and use different methods conclusions should be taken with caution