Genetic Screening and Price Discrimination in Insurance Markets

Basing insurance prices on the results of an imperfect screening test to identify risk types can reduce or increase aggregate discrimination across insureds. We present a powerful and general new framework of analysis to examine this issue, rawing upon recent work which uses decomposable inequality indices to measure vertical and horizontal inequity in taxation. We find that, whilst improved test performance inevitably reduces vertical discrimination (in the average prices faced by different risk types), even very accurate tests can lead to substantial horizontal discrimination (within risk types) and enhanced overall discrimination. These conclusions are shown to be robust to a range of different value judgements about how to aggregate individual discriminatory effects and to be particularly relevant to the case of genetic screeninginsurance, genetic information, discrimination

The state of primate enrichment in Australasian zoos

Eleven Australasian zoos housing primates were included in a large international ‘captive mammal enrichment survey’. Individuals who directly work with, research and manage captive mammals were invited to participate in the survey which was comprised of three sections. The first section was designed to identify current enrichment practices and the factors that limit the quality and quantity of enrichment provided to captive mammals. The aim of the second section was to ascertain current methods used in the evaluation of enrichment and establish the factors that limit the frequency and quality of this evaluation. A third section was incorporated in the survey to determine respondents’ interest in potential applications of an automated enrichment system which is currently being designed to reduce many of the current limitations involved with implementing and evaluating enrichment. As expected, animals from the Primate order were most often provided with enrichment. However, the survey identified that lack of available staff time was the greatest factor limiting both the provision and evaluation of enrichment. Accordingly, the majority of survey respondents agreed that more enrichment would be provided if this was manageable. Overall, there was a very high level of interest from Australasian respondents in the applications of an automated enrichment system as a tool to provide and evaluate a greater quantity, variety and frequency of enrichment for captive mammals without requiring additional staff time

Risk factors for fatality in HIV-infected patients with dideoxynucleoside-induced severe hyperlactataemia or lactic acidosis.

BACKGROUND: Lactic acidosis (LA) and severe hyperlactataemia (HL) are infrequent but serious complications of antiretroviral therapy that have been associated with a high fatality rate. METHODS: In a multinational retrospective cohort study, LA was defined as arterial blood pH5 mmol/l. Logistic regression was used to identify factors associated with fatality. Sensitivity and specificity of different case definitions as predictors of death were compared. RESULTS: The overall case-fatality rate was 19/110 (17.3%), but among acidotic patients it was 33% (16/49 cases). There were 10 asymptomatic patients and none of them died as a consequence of the event. The median lactate for fatal, non-fatal and all patients was 8.3 mmol/l (IQR 7.2-13.1), 6.4 mmol/l (IQR 5.4-7.8) and 6.7 mmol/l (IQR 5.5-8.1), respectively. After adjusting for age and current CD4(+) T-cell count, lactate >7 mmol/l (OR 6.27, 95% CI 1.13-34.93), blood bicarbonate 18 mmol/l, 95% CI 1.33-75.65) and concurrent opportunistic infections (OR 8.69, 95% CI 1.45-52.22) were independently associated with case fatality. Blood lactate >7 mmol/l showed a sensitivity of 84% for fatality with a specificity of 60%, whereas bicarbonate 7 mmol/l and blood bicarbonate <18 mmol/l appear to predict death and might help clinicians in selecting patients who may benefit from more intense monitoring

Late-Onset Erythropoietic Porphyria Caused by a Chromosome 18q Deletion in Erythroid Cells

The erythropoietic porphyrias, erythropoietic protoporphyria and congenital erythropoietic porphyria, result from germline mutations in the ferrochelatase gene and uroporphyrinogen III synthase gene, respectively. Both conditions normally present in childhood but rare cases with onset past the age of 40 y have been reported. Here we show that late-onset erythropoietic protoporphyria can be caused by deletion of the ferrochelatase gene in hematopoietic cells with clonal expansion as part of the myelodysplastic process. This is the first direct demonstration of porphyria produced by an acquired molecular defect restricted to one tissue. Some other cases of late-onset erythropoietic porphyria may be explained by a similar mechanism

From sticky-hard-sphere to Lennard-Jones-type clusters.

A relation M_{SHS→LJ} between the set of nonisomorphic sticky-hard-sphere clusters M_{SHS} and the sets of local energy minima M_{LJ} of the (m,n)-Lennard-Jones potential V_{mn}^{LJ}(r)=ɛ/n-m[mr^{-n}-nr^{-m}] is established. The number of nonisomorphic stable clusters depends strongly and nontrivially on both m and n and increases exponentially with increasing cluster size N for N≳10. While the map from M_{SHS}→M_{SHS→LJ} is noninjective and nonsurjective, the number of Lennard-Jones structures missing from the map is relatively small for cluster sizes up to N=13, and most of the missing structures correspond to energetically unfavorable minima even for fairly low (m,n). Furthermore, even the softest Lennard-Jones potential predicts that the coordination of 13 spheres around a central sphere is problematic (the Gregory-Newton problem). A more realistic extended Lennard-Jones potential chosen from coupled-cluster calculations for a rare gas dimer leads to a substantial increase in the number of nonisomorphic clusters, even though the potential curve is very similar to a (6,12)-Lennard-Jones potential.epsr

Molecular dynamics simulations of glassy polymers

We review recent results from computer simulation studies of polymer glasses, from chain dynamics around the glass transition temperature Tg to the mechanical behaviour below Tg. These results clearly show that modern computer simulations are able to address and give clear answers to some important issues in the field, in spite of the obvious limitations in terms of length and time scales. In the present review we discuss the cooling rate effects, and dynamic slowing down of different relaxation processes when approaching Tg for both model and chemistry-specific polymer glasses. The impact of geometric confinement on the glass transition is discussed in detail. We also show that computer simulations are very useful tools to study structure and mechanical response of glassy polymers. The influence of large deformations on mechanical behaviour of polymer glasses in general, and strain hardening effect in particular are reviewed. Finally, we suggest some directions for future research, which we believe will be soon within the capabilities of state of the art computer simulations, and correspond to problems of fundamental interest.Comment: To apear in "Soft Matter

Emission angle dependent pion interferometry at RHIC and beyond

We use hydrodynamics to generate freeze-out configurations for non-central heavy-ion collisions at present and future collider energies. Such collisions are known to produce strong elliptic flow. The accompanying space-time structure of the source at freeze-out is analyzed using pion interferometry. Between RHIC and LHC energies the source deformation in the transverse plane changes sign. This leaves characteristic signatures in the emission angle dependence of the HBT radii.Comment: Minor changes (some references and discussion added), accepted by Physics Letters