269 research outputs found

    A Multiple Streams Approach to Bioterrorism Policy

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    Bioterrorism is not a new phenomenon and the issues that surround bioterrorism are complex. This paper focuses on the history of bioterrorism, its current threat in public view, and then applying a theory in which explains how those problems became issues in government. The paper starts by examining a historical account of bioterrorism. The history serves a purpose to discuss the ongoing developments and struggles of drafting legislation for an ongoing problem. After a discussion of bioterrorism from a historical perspective, the paper examines the current threat or state of bioterrorism. This will lead into a discussion about John Kingdon’s Multiple Streams Theory and its application to bioterrorism policy. After a discussion about the theory, it will be applied to the Clinton, Bush, and Obama administrations. This application will show that bioterrorism a complex issue and legislation surrounding bioterrorism is as equally as convoluted

    High Genetic Diversity Despite the Potential for Stepping-Stone Colonizations in an Invasive Species of Gecko on Moorea, French Polynesia

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    Invasive species often have reduced genetic diversity, but the opposite can be true if there have been multiple introductions and genetic admixture. Reduced diversity is most likely soon after establishment, in remote locations, when there is lower propagule pressure and with stepping-stone colonizations. The common house gecko (Hemidactylus frenatus) was introduced to Moorea, French Polynesia in the remote eastern Pacific within the last two decades and accordingly is expected to exhibit low diversity. In contrast, we show that H. frenatus on Moorea has exceptionally high genetic diversity, similar to that near the native range in Asia and much higher than reported for other Pacific island reptiles. The high diversity in this recently founded population likely reflects extensive genetic admixture in source population(s) and a life history that promotes retention of diversity. These observations point to the importance of understanding range-wide dynamics of genetic admixture in highly invasive species

    Flapping Wing Micro Air Vehicle Bench Test Setup

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    The purpose of this research was to develop testing methods that can be used to determine the forces, moments, and deflections involved in flapping wing aerodynamics. To pursue the research, a flapping wing mechanism and wings with spans ranging from 9.1 inches to 12.1 inches were built. A variety of mechanisms, capable of, alternatively, purely flapping, flapping with pitch, and flapping with pitch and out-of-plane motion were conceptualized and drawn using solid modeling software. Two of the simpler designs, a single degree-of-freedom flapping mechanism and the two-degree of freedom flapping mechanism were fabricated using a rapid prototype 3-D printer, and sustained operation was demonstrated. A thrust stand and a six-component force balance were used to gather force data from the flapping-only mechanism, combined with a variety of wing shapes. Four high-speed cameras were used to capture the motion of the wings. To minimize intrusiveness an array of laser dots was projected onto the wing during flapping and photogrammetry software was used to analyze the images and determine a shape profile of the wing composed of a frame and membrane during flapping. While the focus of this research was on the bench test setup development, some insight into the influence of wing design on the forces acting on the mechanism was gained

    Landscape Genetics of Raccoons (\u3ci\u3eProcyon lotor\u3c/i\u3e) Associated with Ridges and Valleys of Pennsylvania: Implications for Oral Rabies Vaccination Programs

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    Raccoons are the reservoir for the raccoon rabies virus variant in the United States. To combat this threat, oral rabies vaccination (ORV) programs are conducted in many eastern states. To aid in these efforts, the genetic structure of raccoons (Procyon lotor) was assessed in southwestern Pennsylvania to determine if select geographic features (i.e., ridges and valleys) serve as corridors or hindrances to raccoon gene flow (e.g., movement) and, therefore, rabies virus trafficking in this physiographic region. Raccoon DNA samples (n = 185) were collected from one ridge site and two adjacent valleys in southwestern Pennsylvania (Westmoreland, Cambria, Fayette, and Somerset counties). Raccoon genetic structure within and among these study sites was characterized at nine microsatellite loci. Results indicated that there was little population subdivision among any sites sampled. Furthermore, analyses using a model-based clustering approach indicated one essentially panmictic population was present among all the raccoons sampled over a reasonably broad geographic area (e.g., sites up to 36 km apart). However, a signature of isolation by distance was detected, suggesting that widths of ORV zones are critical for success. Combined, these data indicate that geographic features within this landscape influence raccoon gene flow only to a limited extent, suggesting that ridges of this physiographic system will not provide substantial long-term natural barriers to rabies virus trafficking. These results may be of value for future ORV efforts in Pennsylvania and other eastern states with similar landscapes

    Phase I study of MLN8237—investigational Aurora A kinase inhibitor—in relapsed/refractory multiple myeloma, Non-Hodgkin lymphoma and chronic lymphocytic leukemia

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    Purpose Amplification or over-expression of the mitotic Aurora A kinase (AAK) has been reported in several heme-lymphatic malignancies. MLN8237 (alisertib) is a novel inhibitor of AAK that is being developed for the treatment of advanced malignancies. The objectives of this phase I study were to establish the safety, tolerability, and pharmacokinetic profiles of escalating doses of MLN8237 in patients with relapsed or refractory heme-lymphatic malignancies. Methods Sequential cohorts of patients received MLN8237 orally as either a powder-in-capsule (PIC) or enteric-coated tablet (ECT) formulation. Patients received MLN8237 PIC 25–90 mg for 14 or 21 consecutive days plus 14 or 7 days’ rest, respectively, or MLN8237 ECT, at a starting dose of 40 mg/day once-daily (QD) for 14 days plus 14 days’ rest, all in 28-day cycles. Subsequent cohorts received MLN8237 ECT 30–50 mg twice-daily (BID) for 7 days plus 14 days’ rest in 21-day cycles. Results Fifty-eight patients were enrolled (PIC n = 28, ECT n = 30). The most frequent grade ≥3 drug-related toxicities were neutropenia (45 %), thrombocytopenia (28 %), anemia (19 %), and leukopenia (19 %). The maximum tolerated dose on the ECT 7-day schedule was 50 mg BID. The terminal half-life of MLN8237 was approximately 19 h. Six (13 %) patients achieved partial responses and 13 (28 %) stable disease. Conclusion The recommended phase II dose of MLN8237 ECT is 50 mg BID for 7 days in 21-day cycles, which is currently being evaluated as a single agent in phase II/III trials in patients with peripheral T-cell lymphoma. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s10637-013-0050-9) contains supplementary material, which is available to authorized users

    Locus-Specific Ribosomal RNA Gene Silencing in Nucleolar Dominance

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    The silencing of one parental set of rRNA genes in a genetic hybrid is an epigenetic phenomenon known as nucleolar dominance. We showed previously that silencing is restricted to the nucleolus organizer regions (NORs), the loci where rRNA genes are tandemly arrayed, and does not spread to or from neighboring protein-coding genes. One hypothesis is that nucleolar dominance is the net result of hundreds of silencing events acting one rRNA gene at a time. A prediction of this hypothesis is that rRNA gene silencing should occur independent of chromosomal location. An alternative hypothesis is that the regulatory unit in nucleolar dominance is the NOR, rather than each individual rRNA gene, in which case NOR localization may be essential for rRNA gene silencing. To test these alternative hypotheses, we examined the fates of rRNA transgenes integrated at ectopic locations. The transgenes were accurately transcribed in all independent transgenic Arabidopsis thaliana lines tested, indicating that NOR localization is not required for rRNA gene expression. Upon crossing the transgenic A. thaliana lines as ovule parents with A. lyrata to form F1 hybrids, a new system for the study of nucleolar dominance, the endogenous rRNA genes located within the A. thaliana NORs are silenced. However, rRNA transgenes escaped silencing in multiple independent hybrids. Collectively, our data suggest that rRNA gene activation can occur in a gene-autonomous fashion, independent of chromosomal location, whereas rRNA gene silencing in nucleolar dominance is locus-dependent
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