Bayesian Nonparametric Hidden Markov Models with application to the analysis of copy-number-variation in mammalian genomes

We consider the development of Bayesian Nonparametric methods for product partition models such as Hidden Markov Models and change point models. Our approach uses a Mixture of Dirichlet Process (MDP) model for the unknown sampling distribution (likelihood) for the observations arising in each state and a computationally efficient data augmentation scheme to aid inference. The method uses novel MCMC methodology which combines recent retrospective sampling methods with the use of slice sampler variables. The methodology is computationally efficient, both in terms of MCMC mixing properties, and robustness to the length of the time series being investigated. Moreover, the method is easy to implement requiring little or no user-interaction. We apply our methodology to the analysis of genomic copy number variation.     

Exploring the Traits of Happy People

This paper explores self-reported happiness across afourfold personality framework that synthesizespsychoanalytic and psychometric approaches topersonality structure. Using survey data from arepresentative sample of the U.S. adult population, weidentified four personality types rooted in two basicdimensions – Extraversion/Introversion andTendermindedness/Toughmindedness. On a general level,we found that Extraverts were happier than Introverts,and Tendermindeds were happier than Toughmindeds. More specifically, we identified patterns ofsimilarities and differences across personality typesin the meaning of happiness with respect to goodeating habits, financial insecurity, anxiety andtension, financial optimism, and health concerns.     

Pachedu‐Zenzele in the Diaspora: Promoting Sexual Health Amongst Zimbabweans in England

Migrants have been found to be at enhanced risk for the Human Immune Deficiency Virus (HIV) in comparison with settled populations. As they migrate, they often bring with them their traditions and cultural values, which may influence the ways they access or make sense of health promotion interventions in the host country. In the diaspora, should they experience compromised citizenship, marked by an unresolved immigration status, some may need to remain invisible and this may include not accessing or presenting late for vital health care interventions. Addressing the needs of such invisible populations is key to health promotion work and paramount to public health interests. This paper describes how ever‐changing “traditions”, in particular the notions of Pachedu and Zenzele, were harnessed to develop ethically grounded sexual health care interventions amongst Zimbabweans in Luton, Bedfordshire, England. These interventions were delivered in mundane settings that formed some of the key everyday networks of this population. The reinvention of “tradition” for the purposes of delivering health and social care interventions has been one of the cornerstones of health promotion interventions in Africa, where the rates of HIV are some of the highest in the world. The concept of Pachedu harnessed confidentiality in the delivery of sexual health interventions with Zenzele calling for communal involvement in such initiatives. A key point that resulted in the success of this intervention was partnership work between statutory providers and the local Zimbabwean population throughout the project’s life span. Rather than being construed as passive recipients of health and social care interventions, local Zimbabweans and their statutory partners were engaged in mutual capacity building initiatives. Local Zimbabweans were also engaged and consulted throughout, from the conceptualization of the project, delivery, monitoring, and dissemination of the findings.     

Structural influences on the relationship between objective and subjective indicators of economic well-being

The study investigated the relationship between objective and subjective indicators of economic well-being within different age, race, and sex groups over time. Stratification theory and an accommodation hypothesis were used to predict differential subjective responses to objective conditions within subgroups. Findings supported the hypothesis that the relationship would be weakest among the oldest age group compared to other age groups. Support was found for the hypothesis that predicted smaller coefficients among subgroups characterized as older, female, and nonwhite. Relationships were found to remain stable within all subgroups over time.     

Convergence of Heavy-tailed Monte Carlo Markov Chain Algorithms

Abstract.  In this paper, we use recent results of Jarner & Roberts ( Ann. Appl. Probab., 12, 2002, 224) to show polynomial convergence rates of Monte Carlo Markov Chain algorithms with polynomial target distributions, in particular random-walk Metropolis algorithms, Langevin algorithms and independence samplers. We also use similar methodology to consider polynomial convergence of the Gibbs sampler on a constrained state space. The main result for the random-walk Metropolis algorithm is that heavy-tailed proposal distributions lead to higher rates of convergence and thus to qualitatively better algorithms as measured, for instance, by the existence of central limit theorems for higher moments. Thus, the paper gives for the first time a theoretical justification for the common belief that heavy-tailed proposal distributions improve convergence in the context of random-walk Metropolis algorithms. Similar results are shown to hold for Langevin algorithms and the independence sampler, while results for the mixing of Gibbs samplers on uniform distributions on constrained spaces are rather different in character.     

Return Migrations of African‐Americans to the South: Reclaiming a Land of Promise,Going Home,or Both?*

Abstract Using samples of census data from the University of Minnesota Population Center's “Integrated Public Use Microdata Series” (IPUMS), we describe trends in African‐American migration to the South across recent decades, and explore the applicability of the concept of “return migration” to various demographic patterns. Our findings suggest that the return movement contains multiple migration streams involving African‐Americans of higher socio‐economic status (compared with both origin and destination populations) moving to both urban and rural destinations. These patterns represent clear differences from the earlier 20^th century's “Great Migration” of African‐Americans from South to North. The recent return migration streams suggest that the South may be replacing the North as a “land of promise” for some upwardly mobile African‐Americans, and may also reflect what Carol Stack (1996) has termed a “call to home” as a motivating factor shaping recent African‐American migration to the rural South.     

From leprosy to The Willow Tree: decoding disability and Islamic spirituality in Iranian film

The lack of attention in academic discourse to representations of disability in films from the Middle East has led to an incomplete picture of representations of disability in global cinema. For instance, the diverse meanings of disability in Iranian cinema and the influence of disability on the emergence of Iranian New Wave cinema have been almost completely ignored by scholars. A number of award-winning films from Iran have featured disability as central to their narratives – such as The House is Black (1963), Taste of Cherry (1997), The Color of Paradise (1999), The Willow Tree (2005), and The Painting Pool (2013). Disability in these films serves alternatively as a symbol of spiritual possibility, a mark of marginalization, and a covert social critique. These films examine the emotional, physical, and social implications of disability, while celebrating the cultural power of film to challenge social, religious, and artistic barriers.     

In the path of heroes: second-generation Tamil-Canadians after the LTTE

This paper explores how second-generation Tamil-Canadian university students have modified their ‘cultural heritage’ in the period after the defeat of the Liberation Tigers of Tamil Eelam (LTTE) in May 2009. Using a generational framework suggested by the work of Karl Mannheim, I show that the events of May 2009 situated second-generation Tamil-Canadian political activism as a response to the ambivalence of their parents to the conflict in Sri Lanka. Second-generation Tamil-Canadians are also shown to have altered the key LTTE symbol of the Maaveerar (great hero) to better fit a transnational social field that is framed by the new realities of post-LTTE Sri Lanka and by intolerance to imported conflict in Canada. I argue that the Tamil second generation is highly engaged with the politics of their cultural identity, and that this engagement may have a lasting influence on transnational Tamil identity and on the political status of the Tamil community within Canada.     

New flexible models generated by gamma random variables for lifetime modeling

In this paper we introduce a new three-parameter exponential-type distribution. The new distribution is quite flexible and can be used effectively in modeling survival data and reliability problems. It can have constant, decreasing, increasing, upside-down bathtub and bathtub-shaped hazard rate functions. It also generalizes some well-known distributions. We discuss maximum likelihood estimation of the model parameters for complete sample and for censored sample. Additionally, we formulate a new cure rate survival model by assuming that the number of competing causes of the event of interest has the Poisson distribution and the time to this event follows the proposed distribution. Maximum likelihood estimation of the model parameters of the new cure rate survival model is discussed for complete sample and censored sample. Two applications to real data are provided to illustrate the flexibility of the new model in practice.