Modelling coseismic displacements during the 1997 Umbria-Marche earthquake (central Italy)

We propose a dislocation model for the two normal faulting earthquakes that struck the central Apennines (Umbria-Marche, Italy) on 1997 September 26 at 00:33 (Mw 5.7) and 09:40 GMT (Mw 6.0). We fit coseismic horizontal and vertical displacements resulting from GPS measurements at several monuments of the IGMI (Istituto Geografico Militare Italiano) by means of a dislocation model in an elastic, homogeneous, isotropic half-space. Our best-fitting model consists of two normal faults whose mechanisms and seismic moments have been taken from CMT solutions; it is consistent with other seismological and geophysical observations. The first fault, which is 6 km long and 7 km wide, ruptured during the 00:33 event with a unilateral rupture towards the SE and an average slip of 27 cm. The second fault is 12 km long and 10 km wide, and ruptured during the 09:40 event with a nearly unilateral rupture towards the NW. Slip distribution on this second fault is non-uniform and is concentrated in its SE portion (maximum slip is 65 cm), where rupture initiated. The 00:33 fault is deeper than the 09:40 one: the top of the first rupture is deeper than 1.7 km; the top of the second is 0.6 km deep. In order to interpret the observed epicentral subsidence we have also considered the contributions of two further moderate-magnitude earthquakes that occurred on 1997 October 3 (Mw 5.2) and 6 (Mw 5.4), immediately before the GPS survey, and were located very close to the 09:40 event of September 26. We compare the pattern of vertical displacements resulting from our forward modelling of GPS data with that derived from SAR interferograms: the fit to SAR data is very good, confirming the reliability of the proposed dislocation model

A cluster-randomised controlled trial comparing school and community-based deworming for soil transmitted helminth control in school-age children: The CoDe-STH trial protocol

Background: Current guidelines and targets for soil-transmitted helminth (STH) control focus on school-based deworming for school-age children, given the high risk of associated morbidity in this age group. However, expanding deworming to all age groups may achieve improved STH control among both the community in general and school-age children, by reducing their risk of reinfection. This trial aims to compare school-based targeted deworming with community-wide mass deworming in terms of impact on STH infections among school-age children. Methods: The CoDe-STH (Community Deworming against STH) trial is a cluster-randomised controlled trial (RCT) in 64 primary schools in Dak Lak province, Vietnam. The control arm will receive one round of school-based targeted deworming with albendazole, while in the intervention arm, community-wide mass deworming with albendazole will be implemented alongside school-based deworming. Prevalence of STH infections will be measured in school-age children at baseline and 12 months following deworming. The primary outcome is hookworm prevalence in school-age children at 12 months, by quantitative PCR. Analysis will be intention-to-treat, with outcomes compared between study arms using generalised linear and non-linear mixed models. Additionally, cost-effectiveness of mass and targeted deworming will be calculated and compared, and focus group discussions and interviews will be used to assess acceptability and feasibility of deworming approaches. Individual based stochastic models will be used to predict the impact of mass and targeted deworming strategies beyond the RCT timeframe to assess the likelihood of parasite population 'bounce-back' if deworming is ceased due to low STH prevalence. Discussion: The first large-scale trial comparing mass and targeted deworming for STH control in South East Asia will provide key information for policy makers regarding the optimal design of STH control programs. Trial registration: ACTRN12619000309189

A tale of industrial stagnation from Africa

Original article can be found at: http://www.tandfonline.com/ Copyright Taylor & FrancisMany African economies have experienced rather dismal industrial development since the 1980s. The consensus is that African firms lack competitiveness in a world with increasing trade openness. What determines competitiveness? A well-known explanation is that resource endowments in Africa favour land not labour, which results in high wages, especially in comparison with 'labour abundant' Asian economies. This paper examines the validity of this view on the basis of the case of Sudan. We demonstrate that the lack of competitiveness of manufacturing industries is not caused by high wages. Assuming a direct relationship between labour productivity and international competitiveness, we argue that acute capacity underutilisation, caused by supply-side constraints, lowers manufacturing productivity, which in turn negatively influences competitiveness.Peer reviewedFinal Accepted Versio

Estimates of chronic hepatitis B virus infection in Australia, 2000

Objectives: To estimate the prevalence of chronic hepatitis B virus (HBV) infection in Australia and attributable proportions associated with specific demographic groups at higher risk of infection. Methods: Two methods were used to estimate prevalence of HBV surface antigen (HBsAg): (1) Population-based: results of a national serosurvey using sera collected opportunistically from laboratories across Australia were used for 1-59 year olds, with the HBsAg prevalence for 50-59 years extrapolated to the population aged 60 years and over; (2) Risk group-based: estimates for selected high-risk groups (injecting drug users, homosexual men, Indigenous Australians and people born in high-prevalence countries), using source data from antenatal HBV screening in central Sydney, HBV prevalence studies, and estimates for low-risk groups (first-time blood donors) were combined proportionally to their representation in the population. Results: Prevalence of HBsAg in the national serosurvey increased, with age, from 0.0% for 1-4 and 5-9 year olds to 1.3-1.8% for the 40-49 year age group. Australian population HBsAg prevalence based on minimum and adjusted estimates from this serosurvey were 91,500 (0.49%) and 163,000 (0.87%) infections, respectively. The risk group method estimated an Australian HBsAg prevalence of 88,000 infections (0.47%). Approximately 50% of people with chronic HBV infection were estimated to be immigrants from either South-East Asia (33.3%) or North-East Asia (16.2%). Conclusion: The range of estimates for chronic HBV infection in Australia is broad, reflecting the uncertainty in source data. A national blood survey encompassing a large and representative population sample may help to provide more accurate estimates. A large proportion of people with chronic HBV infection are Asian born

Incidence and risk factors for hepatitis C seroconversion in injecting drug users in Australia

Aims To determine the incidence of hepatitis C virus (HCV) infection and identify risk factors for seroconversion. Design Prospective cohort study. Participants were recruited through direct approaches, street-based outreach, methadone and sexual health clinics and needle and syringe programmes. Setting Urban, regional and rural settings in New South Wales, Australia. Participants Injecting drug users (IDUs) (n=584) were screened and tested for exposure to HCV. Between 1999 and 2002 antibody HCV negative IDUs (n=368) were enrolled and followed-up every 3-6months until seroconversion or study completion. Measurements Interviewer-administered baseline and follow-up questionnaires consisted of 131 items and included demographics, drug use and risk behaviour. Approximately 10cc of whole blood was drawn at each visit. Specimens were stored at 70C and serology performed using one or two third-generation enzyme-linked immunosorbent assays and polymerase chain reaction testing. Findings Sixty-eight seroconversions were observed and incidence was 30.8 per 100 person-years, with incidence in IDUs injecting \u3c 1year, 133 per 100 person-years. Independent predictors of seroconversion were female gender, duration of injecting, injecting cocaine, shared use of filters and recruitment strategy. Conclusions Women, new initiates and IDUs recruited via outreach appear to be at increased risk of infection. Results confirm the significance of cocaine injection as a risk factor and provide the first evidence outside North America of the link between shared use of drug preparation equipment and incident HCV infection. Prevention efforts should attempt to raise awareness of the risks associated with drug sharing and, in particular, the role of potentially contaminated syringes in HCV infection