5,212 research outputs found
Entry, Contestability, and Deregulated Airline Markets: An Event Study Analysis of People Express
A number of recent papers have studied the relationship between price and market structure in the deregulated airline industry through a cross-sectional analysis of city-pair markets. Yet, while interesting, several potential difficulties underlie the inferences drawn in these analyses. In this paper, we consider an alternative approach that uses stock price reactions to entry announcements to shed light on the nature of competitive behavior in this industry. The analysis sheds light on three issues. First, it offers a clean test of contestable market theory. Second, it provides evidence on the level of profits or sunk costs present in these markets. Third, it sheds light on the degree of competitive "localization" existing in the industry. The particular entry events that we focus on are those involving People Express Airline in 1984 and 1985. To provide a more complete picture of the effects of these entry events, we also examine the price and quantity changes that occurred following entry.
NUE: Nano Science And Laboratory Experience (ScALE) at UMaine
This Nanotechnology Undergraduate Education (NUE) in Engineering program entitled, NUE: Nano Science And Laboratory Experience (ScALE) at UMaine , at the University of Maine, under the direction of Dr. Rosemary L. Smith, aims to introduce the basic concepts, applications, and implications of nanoscale science and engineering to all first-year engineering students at the University of Maine (UMaine). The proposed approach is to add nanoscience and nanoscale engineering content to the required \u27introduction to\u27 engineering courses offered by each engineering department. This content will be designed, developed and delivered as a \u27drop-in\u27 module, in collaboration with the instructors for each department\u27s course. This project further aims to enhance undergraduate education and training in nanoscale science and engineering by establishing a college-wide minor in Nanotechnology, developing an upper level course in nanoscience, and to broaden participation of 1st and 2nd year students from underrepresented groups in nanoscale research. The broader impacts of this project include improved student recruitment, retention, and future workforce preparation achieved through the intentional integration of research and education at the undergraduate level, professional development of Maine\u27s middle-school science teachers, the facilitation of new research and education collaborations among UMaine faculty with interests in nanoscale science and engineering, and the sharing of state-of-the-art instructional tools such as laboratory facilities and materials. Outreach activities will focus on increasing the interest of female students in engineering careers by developing mini-projects for high school students targeting nanotechnology applications to biomedicine and energy
Advanced Stirling Convertor Development for NASA Radioisotope Power Systems
Sunpower Inc.'s Advanced Stirling Convertor (ASC) initiated development under contract to the NASA Glenn Research Center and after a series of successful demonstrations, the ASC began transitioning from a technology development project to a flight development project. The ASC has very high power conversion efficiency making it attractive for future Radioisotope Power Systems (RPS) in order to make best use of the low plutonium-238 fuel inventory in the United States. In recent years, the ASC became part of the NASA and Department of Energy (DOE) Advanced Stirling Radioisotope Generator (ASRG) Integrated Project. Sunpower held two parallel contracts to produce ASCs, one with the DOE and Lockheed Martin to produce the ASC-F flight convertors, and one with NASA Glenn for the production of ASC-E3 engineering units, the initial units of which served as production pathfinders. The integrated ASC technical team successfully overcame various technical challenges that led to the completion and delivery of the first two pairs of flightlike ASC-E3 by 2013. However, in late fall 2013, the DOE initiated termination of the Lockheed Martin ASRG flight development contract driven primarily by budget constraints. NASA continues to recognize the importance of high-efficiency ASC power conversion for RPS and continues investment in the technology including the continuation of ASC-E3 production at Sunpower and the assembly of the ASRG Engineering Unit #2. This paper provides a summary of ASC technical accomplishments, overview of tests at Glenn, plans for continued ASC production at Sunpower, and status of Stirling technology development
Treatment regimens and outcomes in severe and moderate haemophilia A in the UK: The THUNDER study
Introduction: The THUNDER study provides an analysis of treatment patterns and outcomes in UK patients with severe or moderate haemophilia A (SHA/MHA) in 2015.
Methods: Patients with SHA or MHA registered with the UK National Haemophilia Database (NHD) were segregated by severity, inhibitor status and age. Haemophilia joint health score (HJHS) was derived from NHD records and treatment regimen and annualized bleed/joint‐bleed rate (ABR/AJBR) from Haemtrack (HT) in HT‐compliant patients.
Results: We report 1810 patients with SHA and 864 with MHA. Prophylaxis was used in 94.9% (n = 130/137) of HT‐compliant children <12 years with SHA, falling to 74.1% (n = 123/166) aged ≥40 years. Median ABR increased with age (1.0, IQR 0.0‐5.0, <12 years; 3.0 IQR, 1.0‐8.0, ≥40 years). Inhibitors were present in 159 (8.8%) SHA and 34 (3.9%) MHA. Median ABR increased from 2.0 (<12 years) to 21.(≥40 years) in SHA inhibitor patients using prophylaxis. Prophylaxis was used by 68.8% of HT‐compliant MHA patients (n = 106) (median FVIII baseline 0.01 IU/mL) associated with a median (IQR) ABR of 3.0 (1.0‐7.0). Median HJHS (n = 453) increased with age in SHA and MHA. Median (IQR) HJHS was higher in SHA inhibitor (17.0, 0.0‐64.5) than non‐ or past inhibitor patients (7.0, 0.0‐23.0).
Conclusions: Increasing ABR with age persists despite current prophylaxis regimens.SHA and MHA had similar ABR/AJBR and HJHS, leading to a suspicion that a subgroup of MHA may be relatively undertreated. More intensive prophylaxis may improve outcomes, but this requires further study
Biomolecule Detection \u3cem\u3evia\u3c/em\u3e Target Mediated Nanoparticle Aggregation and Dielectrophoretic Impedance Measurement
A new biosensing system is described that is based on the aggregation of nanoparticles by a target biological molecule and dielectrophoretic impedance measurement of these aggregates. The aggregation process was verified within a microchannel via fluorescence microscopy, demonstrating that this process can be used in a real time sensor application. Positive dielectrophoresis is employed to capture the nanoparticle aggregates at the edge of thin film electrodes, where their presence is detected either by optical imaging via fluorescence microscopy or by measuring the change in electrical impedance between adjacent electrodes. The electrical detection mechanism demonstrates the potential for this method as a micro total analysis system (mTAS)
Unitary designs and codes
A unitary design is a collection of unitary matrices that approximate the
entire unitary group, much like a spherical design approximates the entire unit
sphere. In this paper, we use irreducible representations of the unitary group
to find a general lower bound on the size of a unitary t-design in U(d), for
any d and t. We also introduce the notion of a unitary code - a subset of U(d)
in which the trace inner product of any pair of matrices is restricted to only
a small number of distinct values - and give an upper bound for the size of a
code of degree s in U(d) for any d and s. These bounds can be strengthened when
the particular inner product values that occur in the code or design are known.
Finally, we describe some constructions of designs: we give an upper bound on
the size of the smallest weighted unitary t-design in U(d), and we catalogue
some t-designs that arise from finite groups.Comment: 25 pages, no figure
Autoimmune hyperphosphatemic tumoral calcinosis in a patient with FGF23 autoantibodies
Hyperphosphatemic familial tumoral calcinosis (HFTC)/hyperostosis-hyperphosphatemia syndrome (HHS) is an autosomal recessive disorder of ectopic calcification due to deficiency of or resistance to intact fibroblast growth factor 23 (iFGF23). Inactivating mutations in FGF23, N-acetylgalactosaminyltransferase 3 (GALNT3), or KLOTHO (KL) have been reported as causing HFTC/HHS. We present what we believe is the first identified case of autoimmune hyperphosphatemic tumoral calcinosis in an 8-year-old boy. In addition to the classical clinical and biochemical features of hyperphosphatemic tumoral calcinosis, the patient exhibited markedly elevated intact and C-terminal FGF23 levels, suggestive of FGF23 resistance. However, no mutations in FGF23, KL, or FGF receptor 1 (FGFR1) were identified. He subsequently developed type 1 diabetes mellitus, which raised the possibility of an autoimmune cause for hyperphosphatemic tumoral calcinosis. Luciferase immunoprecipitation systems revealed markedly elevated FGF23 autoantibodies without detectable FGFR1 or Klotho autoantibodies. Using an in vitro FGF23 functional assay, we found that the FGF23 autoantibodies in the patient's plasma blocked downstream signaling via the MAPK/ERK signaling pathway in a dose-dependent manner. Thus, this report describes the first case, to our knowledge, of autoimmune hyperphosphatemic tumoral calcinosis with pathogenic autoantibodies targeting FGF23. Identification of this pathophysiology extends the etiologic spectrum of hyperphosphatemic tumoral calcinosis and suggests that immunomodulatory therapy may be an effective treatment
Miniature Resistance Measurement Device for Structural Health Monitoring of Reinforced Concrete Infrastructure
A vast amount of civil infrastructure is constructed using reinforced concrete, which can be susceptible to corrosion, posing significant risks. Corrosion of reinforced concrete has various causes, with chloride ingress known to be a major contributor. Monitoring this chloride ingress would allow for preventative maintenance to be less intrusive at a lower cost. Currently, chloride sensing methods are bulky and expensive, leaving the majority of concrete infrastructures unmonitored. This paper presents the design and fabrication of a miniature, low-cost device that can be embedded into concrete at various locations and depths. The device measures localized concrete resistance, correlating to the chloride ingress in the concrete using equations listed in this paper, and calculated results from two experiments are presented. The device benefits from a four-probe architecture, injecting a fixed frequency AC waveform across its outer electrodes within the cement block. Voltage across the internal electrodes is measured with a microcontroller and converted to a resistance value, communicated serially to an external computer. A final test showcases the ability of the device for three-dimensional mass deployment
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