Linearized inverse scattering based on seismic Reverse Time Migration

In this paper we study the linearized inverse problem associated with imaging of reflection seismic data. We introduce an inverse scattering transform derived from reverse-time migration (RTM). In the process, the explicit evaluation of the so-called normal operator is avoided, while other differential and pseudodifferential operator factors are introduced. We prove that, under certain conditions, the transform yields a partial inverse, and support this with numerical simulations. In addition, we explain the recently discussed 'low-frequency artifacts' in RTM, which are naturally removed by the new method

A comparison of the EuroQol and the Health Utilities Index in patients treated for congenital anomalies

It seems generally believed that the HUI3 is a more responsive utility measure than the EQ-5D because of the crude level structure of the EQ-5D compared to the HUI3. As empirical evidence to support this hypothesis is lacking, we undertook a study to compare the construct validity of the utility indices of the EQ-5Dindex and the HUI3index in 135 patients treated for congenital anorectal malformation and 57 patients treated for congenital diaphragmatic hernia. Discriminant validity was tested by the ability of the HUI3index and EQ-5Dindex to distinguish clinically relevant subgroups in the patient populations. Convergent validity was tested using Pearson correlations of the HUI3index and the EQ-5Dindex with the symptom scores. In general the index scores were in line with expectations: the higher the level of symptomaticity, the lower the indices. The HUI3 classified patients in more health states than the EQ-5D and classified a smaller percentage in the best health state. Nevertheless, the EQ-5Dindex distinguished more clinically relevant subgroups than the HUI3index. The two indices were correlated weakly to moderately with the symptom scores, which was expected given the relatively good quality of life of the patients. Despite the higher number of health states of the HUI, the EQ-5Dindex discriminated more clinically relevant subgroups than the HUI3index. This means that discriminative power of the utility indices is not determined merely by the number of health states of the underlying classification system. Differences in the description of the health states might explain this finding.</p

How young people from culturally and linguistically diverse backgrounds experience mental health: some insights for mental health nurses

This article reports on a part of a study which looked at the mental health of culturally and linguistically diverse (CALD) young people. The research sought to learn from CALD young people, carers, and service providers experiences relevant to the mental health of this group of young people. The ultimate goal was to gain insights that would inform government policy, service providers, ethnic communities and most importantly the young people themselves. To this end, qualitative interviews were undertaken with 123 CALD young people, 41 carers and 14 mental health service providers in Queensland, Western Australia and South Australia. Only one aspect of the study will be dealt with here, namely the views of the young CALD participants, which included risk factors, coping strategies and recommendations about how they could be supported in their struggle to maintain mental health. One of the most important findings of the study relates to the resilience of these young people and an insight into the strategies that they used to cope. The efforts of these young people to assist us in our attempts to understand their situation deserve to be rewarded by improvements in the care that we provide. To this end this article sets out to inform mental health nurses of the results of the study so that they will be in a position to better understand the needs and strengths of their CALD clients and be in a better position to work effectively with them

Characteristics of individuals seeking a text messaging intervention for problem drinking: Adults 51 and older versus middle-aged and younger adults

According to the Institute of Medicine, the vast older adult population is estimated to have mental health and substance use disorders at unprecedented rates and will place high demand on an unprepared healthcare system. Online and mobile health interventions, such as text messaging, could provide an alternative form of frontline intervention that could alleviate some of the burden on the healthcare system; however, it remains unknown what are characteristics of adults over 50 who might be interested in a mobile health behavioral intervention and how they may differ from their younger counterparts. To explore the characteristics of those interested in a text messaging intervention by age, we examined screening data for a randomized controlled trial testing a text messaging intervention to reduce drinking among 1,128 hazardous and problem drinkers, aged 21-30, 31-50, and 51 and older. Participants were recruited online through website advertising on alcoholscreening.org and moderationmanagement.org. Results demonstrated that over a quarter of individuals pursuing online and/or text messaging treatment were 51 and older. These participants reported heavy drinking, with significantly greater number of days drinking and binge drinking than the younger groups, but with fewer consequences. Across age groups, a vast majority of participants were female. Findings demonstrate that a group of adult heavy drinkers 51 and older already pursue online treatment and are interested in using a text messaging intervention to help them reduce drinking, suggesting an avenue to engage this population using an alternative frontline treatment

Advances and challenges in predicting the impact of lymphatic filariasis elimination programmes by mathematical modelling

Mathematical simulation models for transmission and control of lymphatic filariasis are useful tools for studying the prospects of lymphatic filariasis elimination. Two simulation models are currently being used. The first, EPIFIL, is a population-based, deterministic model that simulates average trends in infection intensity over time. The second, LYMFASIM, is an individual-based, stochastic model that simulates acquisition and loss of infection for each individual in the simulated population, taking account of individual characteristics. For settings like Pondicherry (India), where Wuchereria bancrofti infection is transmitted by Culex quinquefasciatus, the models give similar predictions of the coverage and number of treatment rounds required to bring microfilaraemia prevalence below a level of 0.5%. Nevertheless, published estimates of the duration of mass treatment required for elimination differed, due to the use of different indicators for elimination (EPIFIL: microfilaraemia prevalence < 0.5% after the last treatment; LYMFASIM: reduction of microfilaraemia prevalence to zero, within 40 years after the start of mass treatment). The two main challenges for future modelling work are: 1) quantification and validation of the models for other regions, for investigation of elimination prospects in situations with other vector-parasite combinations and endemicity levels than in Pondicherry; 2) application of the models to address a range of programmatic issues related to the monitoring and evaluation of ongoing control programmes. The models' usefulness could be enhanced by several extensions; inclusion of different diagnostic tests and natural history of disease in the models is of particular relevance

Windtunnel model position and orientation

In this contribution the determination of the position of moving and deforming objects in windtunnels from CCD camera information is studied. An analytical approach is discussed which solves the problem directly from manipulating nonlinear distance formulae. Also a least-squares approach is given, which is most convenient to implement from a numerical point of view