1,874 research outputs found

    Further investigations into the term structure of interest rates

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    Recent empirical term structure literature questions the usefulness of the standard three-parameter yield curve model in the wake of the Global Financial Crisis and the widespread adoption of unconventional monetary policies, such as Large-scale Asset Purchases (LSAP). This thesis builds on these concerns by extracting a new parameter from the term structure that measures the position of the traditional hump in the yield curve along the maturity axis. My alternative decomposition of the term structure makes it easier to track-down the influence of quantities on interest rates. Given that Treasuries are held as safe assets by many investor types, I interpret the new parameter as a gauge of investors’ risk appetite. It is time-varying and pro-cyclical, leading the business cycle and indexes of financial stress by several months and forming part of the risk-taking policy transmission channel. My results contradict the widely-held view from event studies that LSAP reduce long-term Treasury yields. They can also explain the often divergent relative movements between Treasury term premia and the premia on risky assets, such as corporate credits

    Implicit theories of child sexual exploitation material users : can they differentiate those also at risk of contact offending?

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    Understanding the risk factors that contribute to contact offending among online sexual offenders is an important topic for both researchers and clinicians working with this population. The present study sought to validate a novel implicit theory (IT) framework developed by Bartels and Merdian (2016) designed to capture the common beliefs of child sexual exploitation material (CSEM) users and assess the risk of contact offending within this group. To achieve this, 29 CSEM offenders (i.e., those with a CSEM offence but no history of child sexual contact offending) and 30 mixed offenders (those with both a CSEM offence and child sexual contact offences) were rated using file data and compared on their endorsement of a combined set of 11 ITs (six CSEM ITs, five contact sexual offender ITs developed by Ward & Keenan, 1999). Analyses showed that both groups endorsed CSEM ITs to a similar degree; however mixed offenders endorsed significantly more Contact ITs in comparison to CSEM offenders. Logistic regression identified two key ITs that were predictive of contact offending, Entitlement and Children as Sexual Beings. Overall this study supports the CSEM IT framework as being able to identify a number of common beliefs in CSEM users, and that the Contact IT framework may provide a way to identify CSEM users who are at risk of committing a child contact sexual offence. Implications for the assessment and treatment of CSEM users are discussed

    A Monte Carlo study of two Compton camera’s first plane detectors

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    Purpose: The suitability of two possible detectors, silicon and germanium as the Compton camera’s first plane detector has been investigated using a robust Monte Carlo approach. Methods: The GEANT4 simulation software was used to simulate the radiation transport and interactions with matter. Investigations were first done by relating the impact of Doppler broadening on the Compton camera angular uncertainty, energy spectra and reconstructed source image. Then, the impact of geometry and interaction type on the Compton camera performance was evaluated as well. Results: Analyses suggest that silicon of about 1 cm thickness would be suitable as the Compton camera first plane detector. The choice of silicon is however not completely flawless, Doppler broadening for this detector material contributes as much as 7.3 mm and 2.4 mm to full-width-half-maximum image resolution at 140.5 keV and 511 keV respectively. Conclusions: It is envisioned that with improved reconstruction technique, silicon would be the best first plane detector for the Compton camera

    Biosynthesis of the Pseudomonas aeruginosa Extracellular Polysaccharides, Alginate, Pel, and Psl

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    Pseudomonas aeruginosa thrives in many aqueous environments and is an opportunistic pathogen that can cause both acute and chronic infections. Environmental conditions and host defenses cause differing stresses on the bacteria, and to survive in vastly different environments, P. aeruginosa must be able to adapt to its surroundings. One strategy for bacterial adaptation is to self-encapsulate with matrix material, primarily composed of secreted extracellular polysaccharides. P. aeruginosa has the genetic capacity to produce at least three secreted polysaccharides; alginate, Psl, and Pel. These polysaccharides differ in chemical structure and in their biosynthetic mechanisms. Since alginate is often associated with chronic pulmonary infections, its biosynthetic pathway is the best characterized. However, alginate is only produced by a subset of P. aeruginosa strains. Most environmental and other clinical isolates secrete either Pel or Psl. Little information is available on the biosynthesis of these polysaccharides. Here, we review the literature on the alginate biosynthetic pathway, with emphasis on recent findings describing the structure of alginate biosynthetic proteins. This information combined with the characterization of the domain architecture of proteins encoded on the Psl and Pel operons allowed us to make predictive models for the biosynthesis of these two polysaccharides. The results indicate that alginate and Pel share certain features, including some biosynthetic proteins with structurally or functionally similar properties. In contrast, Psl biosynthesis resembles the EPS/CPS capsular biosynthesis pathway of Escherichia coli, where the Psl pentameric subunits are assembled in association with an isoprenoid lipid carrier. These models and the environmental cues that cause the cells to produce predominantly one polysaccharide over the others are subjects of current investigation

    Further investigations into the term structure of interest rates

    Get PDF
    Recent empirical term structure literature questions the usefulness of the standard three-parameter yield curve model in the wake of the Global Financial Crisis and the widespread adoption of unconventional monetary policies, such as Large-scale Asset Purchases (LSAP). This thesis builds on these concerns by extracting a new parameter from the term structure that measures the position of the traditional hump in the yield curve along the maturity axis. My alternative decomposition of the term structure makes it easier to track-down the influence of quantities on interest rates. Given that Treasuries are held as safe assets by many investor types, I interpret the new parameter as a gauge of investors’ risk appetite. It is time-varying and pro-cyclical, leading the business cycle and indexes of financial stress by several months and forming part of the risk-taking policy transmission channel. My results contradict the widely-held view from event studies that LSAP reduce long-term Treasury yields. They can also explain the often divergent relative movements between Treasury term premia and the premia on risky assets, such as corporate credits

    Searching for Faint Planetary Nebulae Using the Digital Sky Survey

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    Recent Halpha surveys such as SHS and IPHAS have improved the completeness of the Galactic planetary nebula (PN) census. We now know of ~3,000 PNe in the Galaxy, but this is far short of most estimates, typically ~25,000 or more for the total population. The size of the Galactic PN population is required to derive an accurate estimate of the chemical enrichment rates of nitrogen, carbon, and helium. In addition, a high PN count (~20,000) is strong evidence that most 1-8 Msun main sequence stars will go through a PN phase, while a low count (<10,000) argues that special conditions (e.g., a close binary interaction) are required to form a PN. We describe a technique for finding hundreds more PNe using the existing data collections of the digital sky surveys, thereby improving the census of Galactic PNe.Comment: 11 pages, 7 figures, accepted for publication in the Publications of the Astronomical Society of Australia (PASA), full resolution paper available at http://www.wiyn.org/jacoby_pasa.pd

    Advancing Health Policy and Advocacy Education in Medical School through a Student-run Elective

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    Introduction: Training medical students in the policy topics of healthcare economics, delivery systems, disparities, and reform helps to prepare them for the growing role of advocacy in medicine. We used a near-peer educational model to create an elective to advance learners’ policy knowledge and advocacy skills, while simultaneously offering student directors hands-on experience in educational program development. Methods: The 4-week elective for fourth year medical students included weekly readings, policy seminars, advocacy workshops, and journal clubs. Longitudinally, students prepared for a policy debate and prepared a research project or Op-Ed article on a healthcare disparity topic of their choice. The elective was designed, coordinated, and implemented by a team of first, second, third, and fourth-year medical students with faculty adviser oversight. Pre- and post-surveys were utilized to assess student learners’ knowledge of subject material and their perceptions of the effectiveness of the curriculum. Student directors self-assessed their confidence with the subject material and acquired skill in educational program development. Results: Student learners (n=6) noted significant improvement in their knowledge of health policy (P=0.0002) and advocacy (P=0.0064). They also reported improvement in several subtopics under policy and advocacy, with significant improvements seen in healthcare reform (P=0.0131) and writing skills (P=0.0099). Student directors (n=4) reported improved skills in curriculum development, educational evaluation, and leadership. Discussion: This novel student-run elective provided effective training in health policy and advocacy that extends beyond traditional curricula in medical school. Employing a near-peer model, the elective offers a sustainable system to educate interested students in these subjects and provide student directors unique experience in medical education. Further evaluation of future iterations will help determine the effectiveness of the curriculum in advancing individual policy and advocacy subtopics to guide future curricular modifications

    Ron knockdown and Ron monoclonal antibody IMC-RON8 sensitize pancreatic cancer to histone deacetylase inhibitors (HDACi).

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    Recepteur d\u27origine nantais (Ron) is overexpressed in a panel of pancreatic cancer cells and tissue samples from pancreatic cancer patients. Ron can be activated by its ligand macrophage stimulating protein (MSP), thereby activating oncogenic signaling pathways. Crosstalk between Ron and EGFR, c-Met, or IGF-1R may provide a mechanism underlying drug resistance. Thus, targeting Ron may represent a novel therapeutic strategy. IMC-RON8 is the first Ron monoclonal antibody (mAb) entering clinical trial for targeting Ron overexpression. Our studies show IMC-RON8 downmodulated Ron expression in pancreatic cancer cells and significantly blocked MSP-stimulated Ron activation, downstream Akt and ERK phosphorylation, and survivin mRNA expression. IMC-RON8 hindered MSP-induced cell migration and reduced cell transformation. Histone deacetylase inhibitors (HDACi) are reported to target expression of various genes through modification of nucleosome histones and non-histone proteins. Our work shows HDACi TSA and Panobinostat (PS) decreased Ron mRNA and protein expression in pancreatic cancer cells. PS also reduced downstream signaling of pAkt, survivin, and XIAP, as well as enhanced cell apoptosis. Interestingly, PS reduced colony formation in Ron knockdown cells to a greater extent than Ron scramble control cells in colony formation and soft agarose assays. IMC-RON8 could also sensitize pancreatic cancer cells to PS, as reflected by reduced colony numbers and size in combination treatment with IMC-RON8 and PS compared to single treatment alone. The co-treatment further reduced Ron expression and pAkt, and increased PARP cleavage compared to either treatment alone. This study suggests the potential for a novel combination approach which may ultimately be of value in treatment of pancreatic cancer

    The Gravitational Wave Treasure Map: A Tool to Coordinate, Visualize, and Assess the Electromagnetic Follow-Up of Gravitational Wave Events

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    We present the Gravitational Wave Treasure Map, a tool to coordinate, visualize, and assess the electromagnetic follow-up of gravitational wave (GW) events. With typical GW localization regions of hundreds to thousands of square degrees and dozens of active follow-up groups, the pursuit of electromagnetic (EM) counterparts is a challenging endeavor, but the scientific payoff for early discovery of any counterpart is clear. With this tool, we provide a website and API interface that allows users to easily see where other groups have searched and better inform their own follow-up search efforts. A strong community of Treasure Map users will increase the overall efficiency of EM counterpart searches and will play a fundamental role in the future of multi-messenger astronomy.Comment: 14 pages, 8 figures, Accepted to Ap
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