Modelling data from single-photon emission computerized tomography

The completely random character of radioactive disintegration provides the basis of a strong justification for a Poisson linear model for single-photon emission computed tomography data, which can be used to produce reconstructions of isotope densities, whether by maximum likelihood or Bayesian methods. However, such a model requires the construction of a matrix of weights, which represent the mean rates of arrival at each detector of photons originating from each point within the body space. Two methods of constructing these weights are discussed, and reconstructions resulting from phantom and real data are presented.     

Dose‐Response Models Incorporating Aerosol Size Dependency for Francisella tularensis

The effect of bioaerosol size was incorporated into predictive dose‐response models for the effects of inhaled aerosols of Francisella tularensis (the causative agent of tularemia) on rhesus monkeys and guinea pigs with bioaerosol diameters ranging between 1.0 and 24 μm. Aerosol‐size‐dependent models were formulated as modification of the exponential and β‐Poisson dose‐response models and model parameters were estimated using maximum likelihood methods and multiple data sets of quantal dose‐response data for which aerosol sizes of inhaled doses were known. Analysis of F. tularensis dose‐response data was best fit by an exponential dose‐response model with a power function including the particle diameter size substituting for the rate parameter k scaling the applied dose. There were differences in the pathogen's aerosol‐size‐dependence equation and models that better represent the observed dose‐response results than the estimate derived from applying the model developed by the International Commission on Radiological Protection (ICRP, 1994) that relies on differential regional lung deposition for human particle exposure.     

‘Actually There is a Brain in There’: Uncovering Complexity in Pathways Through Education for Young Adults Who Have Been in Care

Internationally, research has highlighted disruption to the educational trajectories of young people in care, documenting concern about upheaval and poor educational outcomes. We present findings from English data arising from qualitative longitudinal research with care experienced people (16–32 years) who were also in education, employment or training. The analysis extends understanding of the experiences of those who achieve educational ‘success’, including those who followed non‐linear trajectories. The need for a flexible education system, and leaving care entitlements, which take into account the disruption experienced by young people in care and the consequent possibility of delayed educational pathways, is discussed.     

Stakeholder Perspectives on Children's Mental Health Needs and Supports in Six Low‐ and Middle‐Income Countries

Low‐ and middle‐income countries (LMIC) are faced with disproportionately high levels of unmet child mental health needs. This study explored through interviews the perspectives of 17 inter‐agency service stakeholders from Brazil, Indonesia, Kenya, Pakistan, Rwanda and Turkey on existing supports and challenges. Four themes emerged on the holistic nature of children's mental health needs linked with disadvantage; limited resources and skilled workforce; stigma; and strategies for future implementation, including awareness, parental engagement, skills‐based programmes and cultural adaptation. Stakeholder input is essential in conceptualising, developing and evaluating culturally appropriate interventions for vulnerable children in LMIC.     

No One Is Immune: A Community Education Partnership Addressing HIV/AIDS and Older Adults

There has been a dramatic increase in the number of new HIV diagnoses among people aged 50 to 64 in the United States, and according to the Centers for Disease Control and Prevention (CDC), in just 7 years (by 2015) 50% of those living with AIDS will be aged 50 or older. To address this public health concern, viable HIV/AIDS prevention and treatment options for individuals over the age of 50 are necessary. This article discusses the No One Is Immune initiative that planned, implemented, and coordinated evidence- based HIV/AIDS prevention and education programs specifically tailored for middle-aged and older adults. Guided by the health belief model, an educational conference entitled "Sexuality, Medication, and HIV/AIDS in Middle and Later Adulthood" was conducted along with research activities that assessed HIV/AIDS knowledge gained using both qualitative and quantitative measures. This project can be replicated by other providers within the aging network.     

Infant Contingency/Extinction Performance After Observing Partial Reinforcement

Social information gathering by infants 6 and 12 months old was examined as a foundation for later social learning that may be uniquely human. Infant performance on a contingency/extinction task was studied following a caregiver demonstration of the contingency on varied reinforcement schedules. Infants who observed caregivers receive any reinforcing stimulation in pretraining decreased responding over their own acquisition period, possibly because they began to habituate to the reinforcer. In extinction, infants who observed caregivers receive partial reinforcement in pretraining were more persistent in responding than others. This suggested that direct experience with partial reinforcement is not needed for greater persistence in extinction. These studies revealed details of social learning in the 1st year.     

Development of a Dose‐Response Model for SARS Coronavirus

In order to develop a dose‐response model for SARS coronavirus (SARS‐CoV), the pooled data sets for infection of transgenic mice susceptible to SARS‐CoV and infection of mice with murine hepatitis virus strain 1, which may be a clinically relevant model of SARS, were fit to beta‐Poisson and exponential models with the maximum likelihood method. The exponential model (k= 4.1 × l0²) could describe the dose‐response relationship of the pooled data sets. The beta‐Poisson model did not provide a statistically significant improvement in fit. With the exponential model, the infectivity of SARS‐CoV was calculated and compared with those of other coronaviruses. The does of SARS‐CoV corresponding to 10% and 50% responses (illness) were estimated at 43 and 280 PFU, respectively. Its estimated infectivity was comparable to that of HCoV‐229E, known as an agent of human common cold, and also similar to those of some animal coronaviruses belonging to the same genetic group. Moreover, the exponential model was applied to the analysis of the epidemiological data of SARS outbreak that occurred at an apartment complex in Hong Kong in 2003. The estimated dose of SARS‐CoV for apartment residents during the outbreak, which was back‐calculated from the reported number of cases, ranged from 16 to 160 PFU/person, depending on the floor. The exponential model developed here is the sole dose‐response model for SARS‐CoV at the present and would enable us to understand the possibility for reemergence of SARS.