Tuesday, January 24th in Olin Hall
Groups 16-23
Rebecca Thomas, Ph.D.
Deriving a Simplified Noun/Verb Vocabulary from a Text
Automatic text simplification is helpful for some audiences, including adults with limited literacy and (our original motivation) people with difficulty speaking who thus make use of Augmented and Assistive Communication devices. Successful text simplification will likely depend on the coordination of software tools including syntactic parsers, semantic knowledge bases, and lexical disambiguation.
Focusing on the lexical portion of text simplification, we propose and evaluate five related algorithms that automatically derive limited-size vocabularies of nouns or verbs from text documents of 2,000-30,000 words. The proposed algorithms combine Personalized Page Rank (Agirre & Soroa, 2009) and principles of information maximization, using WordNet (Miller, 1995) as an additional source of semantic information.
For the best-performing algorithm, the difference between automatically generated reduced-size vocabularies and the vocabularies used by human writers of simplified (and therefore limited-vocabulary) texts is approximately 1-2 WordNet graph edges per word. The best-performing algorithm performs word-sense disambiguation with sentence-level context information at the earliest stage of analysis, indicating that this computationally expensive task is nonetheless valuable.
Anna Tyler, Ph.D.
Functional reorganization in the hippocampus following status epilepticus correlates with memory deficits in rats
Status epilepticus (SE), an epileptic seizure lasting 30 or more minutes, is a common medical neurological emergency. It is associated with the later development of epilepsy, behavioral disruption and cognitive impairment. In both humans and rats, SE has been shown to lead to neuronal loss in the limbic system, predominantly in the hippocampus, as well as mossy fiber sprouting in the dentate gyrus. Although neuronal death may contribute to cognitive impairment, it is also possible that the communication between remaining neurons is reorganized, and that this reorganization contributes to reduced cognitive abilities. To investigate this possibility, we examine the effects of SE on the structure of functional networks in the rat hippocampus. We use entropy maximization to build functional networks between single neurons recorded in the rat hippocampus. We find that structural changes in these networks following SE correlate with deficits in spatial memory.
Guillaume Vogt, Ph.D.
In vitro differentiation of human macrophages with enhanced antimycobacterial activity
Mycobacterium tuberculosis causes widespread, persistent infection, often residing in macrophages that neither sterilize the bacilli nor allow them to cause disease. How macrophages restrict growth of pathogens is one of many aspects of human phagocyte biology whose study relies largely on macrophages differentiated from monocytes in vitro. However, such cells fail to recapitulate the phenotype of tissue macrophages in key respects, including that they support early, extensive replication of M. tuberculosis and die in several days. Here we found that human macrophages could survive infection, kill Mycobacterium bovis BCG, and severely limit the replication of M. tuberculosis for several weeks if differentiated in 40% human plasma under 5%–10% (physiologic) oxygen in the presence of GM-CSF and/or TNF-α followed by IFN-γ. Control was lost with fetal bovine serum, 20% oxygen, M-CSF, higher concentrations of cytokines, or premature exposure to IFN-γ. We believe that the new culture method will enable inquiries into the antimicrobial mechanisms of human macrophages.
Marcienne Wright, Ph.D.
Advancing Federal Biosafety and Biosecurity Policy to Strengthen Global Health Security
Biorisk management describes the practice of strengthening the biosafety, biocontainment, and biosecurity postures of research and clinical laboratories. Biosafety refers to the use of a combination of practices, safety equipment and engineering controls to prevent the transmission of laboratory pathogens to laboratory workers and to the environment. Biocontainment refers to the application of biosafety principles in high (BSL3) and maximum (BSL4) containment research laboratories. Biosecurity controls in laboratories are implemented to prevent the intentional use of pathogenic agents to compromise human, animal or agricultural health security. As a biosafety and biosecurity program analyst for the U.S. Department of Health and Human Services, I work with multiple agencies in the federal government to develop and evaluate biorisk management policy for U.S. and international life science research programs. My office’s policy focus (or portfolio) includes the evaluation and development of federal biosafety policy for the operation and construction of high and maximum containment laboratories, the use of recombinant and synthetic DNA and the governance of dual-use research and federal Select Agent Regulations. Additionally, I conduct biorisk assessments for infectious diseases and recombinant DNA life science research projects at the university level and provide guidance for the safe use of these agents in the laboratory. I earned my BA in Biology from Williams College, my PhD in Biochemistry and Molecular Genetics from the University of Alabama at Birmingham, and completed my postdoctoral work in biosafety at the National Institutes of Health. I am now an AAAS Science and Technology Policy Fellow supporting the mission of the US Department of Health and Human Services.
