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- Creators: School of Politics and Global Studies
The transmission dynamics of Tuberculosis (TB) involve complex epidemiological and socio-economical interactions between individuals living in highly distinct regional conditions. The level of exogenous reinfection and first time infection rates within high-incidence settings may influence the impact of control programs on TB prevalence. The impact that effective population size and the distribution of individuals’ residence times in different patches have on TB transmission and control are studied using selected scenarios where risk is defined by the estimated or perceive first time infection and/or exogenous re-infection rates.
Methods
This study aims at enhancing the understanding of TB dynamics, within simplified, two patch, risk-defined environments, in the presence of short term mobility and variations in reinfection and infection rates via a mathematical model. The modeling framework captures the role of individuals’ ‘daily’ dynamics within and between places of residency, work or business via the average proportion of time spent in residence and as visitors to TB-risk environments (patches). As a result, the effective population size of Patch i (home of i-residents) at time t must account for visitors and residents of Patch i, at time t.
Results
The study identifies critical social behaviors mechanisms that can facilitate or eliminate TB infection in vulnerable populations. The results suggest that short-term mobility between heterogeneous patches contributes to significant overall increases in TB prevalence when risk is considered only in terms of direct new infection transmission, compared to the effect of exogenous reinfection. Although, the role of exogenous reinfection increases the risk that come from large movement of individuals, due to catastrophes or conflict, to TB-free areas.
Conclusions
The study highlights that allowing infected individuals to move from high to low TB prevalence areas (for example via the sharing of treatment and isolation facilities) may lead to a reduction in the total TB prevalence in the overall population. The higher the population size heterogeneity between distinct risk patches, the larger the benefit (low overall prevalence) under the same “traveling” patterns. Policies need to account for population specific factors (such as risks that are inherent with high levels of migration, local and regional mobility patterns, and first time infection rates) in order to be long lasting, effective and results in low number of drug resistant cases.
The maintenance of chromosomal integrity is an essential task of every living organism and cellular repair mechanisms exist to guard against insults to DNA. Given the importance of this process, it is expected that DNA repair proteins would be evolutionarily conserved, exhibiting very minimal sequence change over time. However, BRCA1, an essential gene involved in DNA repair, has been reported to be evolving rapidly despite the fact that many protein-altering mutations within this gene convey a significantly elevated risk for breast and ovarian cancers.
Results
To obtain a deeper understanding of the evolutionary trajectory of BRCA1, we analyzed complete BRCA1 gene sequences from 23 primate species. We show that specific amino acid sites have experienced repeated selection for amino acid replacement over primate evolution. This selection has been focused specifically on humans and our closest living relatives, chimpanzees (Pan troglodytes) and bonobos (Pan paniscus). After examining BRCA1 polymorphisms in 7 bonobo, 44 chimpanzee, and 44 rhesus macaque (Macaca mulatta) individuals, we find considerable variation within each of these species and evidence for recent selection in chimpanzee populations. Finally, we also sequenced and analyzed BRCA2 from 24 primate species and find that this gene has also evolved under positive selection.
Conclusions
While mutations leading to truncated forms of BRCA1 are clearly linked to cancer phenotypes in humans, there is also an underlying selective pressure in favor of amino acid-altering substitutions in this gene. A hypothesis where viruses are the drivers of this natural selection is discussed.
Learning Sparse Representations for Fruit-Fly Gene Expression Pattern Image Annotation and Retrieval
Fruit fly embryogenesis is one of the best understood animal development systems, and the spatiotemporal gene expression dynamics in this process are captured by digital images. Analysis of these high-throughput images will provide novel insights into the functions, interactions, and networks of animal genes governing development. To facilitate comparative analysis, web-based interfaces have been developed to conduct image retrieval based on body part keywords and images. Currently, the keyword annotation of spatiotemporal gene expression patterns is conducted manually. However, this manual practice does not scale with the continuously expanding collection of images. In addition, existing image retrieval systems based on the expression patterns may be made more accurate using keywords.
Results
In this article, we adapt advanced data mining and computer vision techniques to address the key challenges in annotating and retrieving fruit fly gene expression pattern images. To boost the performance of image annotation and retrieval, we propose representations integrating spatial information and sparse features, overcoming the limitations of prior schemes.
Conclusions
We perform systematic experimental studies to evaluate the proposed schemes in comparison with current methods. Experimental results indicate that the integration of spatial information and sparse features lead to consistent performance improvement in image annotation, while for the task of retrieval, sparse features alone yields better results.
The right to cast a meaningful vote, equal in value to other votes, is a fundamental tenet US elections. Despite the 1964 Supreme Court decision formally establishing the one person, one vote principle as a legal requirement of elections, our democracy consistently falls short of it. With mechanisms including the winner-take-all format in the Electoral College, disproportioned geographic allocation of senators, extreme partisan gerrymandering in the House of Representatives, and first-past-the-post elections, many voters experience severe vote dilution. <br/><br/>In order to legitimize our democratic structures, American elections should be reformed so every person’s vote has equal weight, ensuring that the election outcomes reflect the will of the people. Altering the current election structure to include more proportional structures including rank choice voting and population-based representation, will result in a democracy more compatible with the one person, one vote principle.
Descriptive representation is important to building and maintaining a fair court system, especially within a context of historical oppression by race or gender. Using official government biographies, voter rolls, news articles, and press releases, I collected demographic information on the judges of Arizona and compared it to Census data, to show how under representative the state courts of Arizona currently are. Through the use of non-attorney judges, the Justice Court of Arizona has become the most representative level of the state court. Almost all of the BIPOC judges of the Justice Court are not attorneys. Allowing non-attorney Justices of the Peace has made it possible for the court to be more representative of Arizonans. However, even though it is the most representative state court, the Justice Court vastly under represents women and BIPOC as judges. As racial tension and movements for fairness under the law increase, it is important to challenge how the courts could better serve Arizona.
This thesis is about how Liberian activists were able to help Liberian immigrants under Temporary Protected Status and Deferred Enforced Departure (DED) to convince President Trump to extend DED policy. They also lobbied members of Congress to pass the Liberian Relief Immigration Fairness Act, which granted permanent legal status to TPS and DED recipients. My research questions were: How did advocacy groups influence politicians? How did the media cover the narrative that advocacy groups crafted? How was the battle to get an effective resolution accomplished? I interviewed advocacy groups and a congressional staffer and analyzed various primary and secondary sources in order to gain historical context. This case study will provide the reader deeper understanding about the complexity of the broken immigration system in the United States that has been ongoing for many years. I will also discuss the Constitutional debate on prosecutorial discretion that continues to raise the alarm on many issues that complicate the process. Additionally, this study will benefit other countries hoping to solve their immigration crisis and more importantly, it will bring awareness to the general public in the United States and help hold elected officials accountable when discussing the betterment of immigration issues. I found that Liberian activists, TPS and DED recipients were very influential in getting favorable legislation passed.