6,221 research outputs found

    Challenges in Teaching Large Online Sections

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    This paper presents a case of a campus based online teaching experience. The case is based on a Management Information Systems course for large sections in two modalities: online and hybrid settings with 30 and 70 students respectively. The purpose of the project is to identify the challenges in teaching large online sections. The main results are that given the current technology, we can overcome the class size limitations for on-line courses; that according to active learning experiences, we can use active learning recommendations in online course design; that given technologies like Blackboard and Breeze, students‟ expectations and needs can be properly fulfilled with large sections; that given differences in course goals, only cognitive based courses can take advantages of online teaching; and that given the characteristics of a Management Information Systems course, it can be taught online. These results are important for researchers, professors, and university authorities

    [Editorial] Accounting scholarship and management by numbers

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    There is a plethora of indices ranking universities, departments, and individual researchers based on a variety of indices. These invariably include a measurement of research, usually based on a combination of quantity and quality of journal publications. Informal discussions with accounting researchers invariably turns to the question of journal rankings and performance management indicators. Why is this so

    Modelling the atomic structure of very high-density amorphous ice

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    The structure of very high-density amorphous (VHDA) ice has been modelled by positionally disordering three crystalline phases, namely ice IV, VI and XII. These phases were chosen because only they are stable or metastable in the region of the ice phase diagram where VHDA ice is formed, and their densities are comparable to that of VHDA ice. An excellent fit to the medium range of the experimentally observed pair-correlation function g(r) of VHDA ice was obtained by introducing disorder into the positions of the H2O molecules, as well as small amounts of molecular rotational disorder, disorder in the O--H bond lengths and disorder in the H--O--H bond angles. The low-k behaviour of the experimental structure factor, S(k), is also very well reproduced by this disordered-crystal model. The fraction of each phase present in the best-fit disordered model is very close to that observed in the probable crystallization products of VHDA ice. In particular, only negligible amounts of ice IV are predicted, in accordance with experimental observation.Comment: 4 pages, 3 figures, 1 table, v2: changes made in response to referees' comments, the justification for using certain ice phases is improved, and ice IV is now disordered as wel

    Chain Galaxies are Edge-On Low Surface Brightness Galaxies

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    Deep HST WFPC2 images have revealed a population of very narrow blue galaxies which Cowie et al. (1996) have interpreted as being a new morphological class of intrinsically linear star forming galaxies at z=0.53z=0.5-3. We show that the same population exists in large numbers at low redshifts (z=0.03) and are actually the edge-on manifestation of low surface brightness disk galaxies.Comment: 18 pages + 3 pages of figures. Uuencoded, gzipped, tar file of 1 latex file, 5 figures, and 2 latex style files. To appear in the Astrophysical Journal Letter

    Non-inherited maternal human leukocyte antigen alleles in susceptibility to familial rheumatoid arthritis.

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    OBJECTIVES: Some patients with rheumatoid arthritis (RA) lack RA-associated human leukocyte antigen (HLA) alleles. Prior studies investigated non-inherited maternal HLA alleles (NIMA) in RA risk with conflicting results. METHODS: We examined NIMA in a large cohort of families from the North American Rheumatoid Arthritis Consortium (NARAC). RESULTS: Among 620 patients with 1 or both parents having a HLA genotype, patients with RA informative for analysis included 176 without HLA-DRB1*04 and 86 without the HLA shared epitope (SE). The frequency of NIMA encoding HLA-DR4 or the SE was compared to the non-inherited paternal allele (NIPA). DR4-encoding NIMA vs NIPA revealed no significant difference (27% vs 20%). However, parity is known to modulate RA risk and analyses stratified by sex and age of onset showed significant variation among women. Interestingly, among women with onset or =45 years at onset the reverse was observed (31% vs 16% compared to 10% vs 60%, p = 0.008). DR4 encoding NIMA vs NIPA did not differ in men. The SE did not differ in men or women. CONCLUSIONS: Risk of RA was associated with HLA-DR4 encoding NIMA in younger-onset women but not in older-onset women or men. These observations could help explain conflicting prior results of NIMA in RA

    Helium, Oxygen, Proton, and Electron (HOPE) Mass Spectrometer for the Radiation Belt Storm Probes Mission

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    The HOPE mass spectrometer of the Radiation Belt Storm Probes (RBSP) mission (renamed the Van Allen Probes) is designed to measure the in situ plasma ion and electron fluxes over 4π sr at each RBSP spacecraft within the terrestrial radiation belts. The scientific goal is to understand the underlying physical processes that govern the radiation belt structure and dynamics. Spectral measurements for both ions and electrons are acquired over 1 eV to 50 keV in 36 log-spaced steps at an energy resolution ΔE FWHM/E≈15 %. The dominant ion species (H+, He+, and O+) of the magnetosphere are identified using foil-based time-of-flight (TOF) mass spectrometry with channel electron multiplier (CEM) detectors. Angular measurements are derived using five polar pixels coplanar with the spacecraft spin axis, and up to 16 azimuthal bins are acquired for each polar pixel over time as the spacecraft spins. Ion and electron measurements are acquired on alternate spacecraft spins. HOPE incorporates several new methods to minimize and monitor the background induced by penetrating particles in the harsh environment of the radiation belts. The absolute efficiencies of detection are continuously monitored, enabling precise, quantitative measurements of electron and ion fluxes and ion species abundances throughout the mission. We describe the engineering approaches for plasma measurements in the radiation belts and present summaries of HOPE measurement strategy and performance

    Case Hepatic Endometriosis: A Continuing Diagnostic Dilemma

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    Background. Intraparenchymal endometriosis of liver is rare. It may present as liver tumour and the diagnosis is not usually established till after surgery. Case Outline. A 48-year-old postmenopausal woman presented with right upper quadrant pain and a cystic liver mass. Liver function tests and tumour markers (αFP, CEA, CA 19-9, and CA 125) were normal. Radiological imaging (USS, CT and MRI) suggested a thick walled cystic mass involving segments IV and VIII with complex intracystic septations. Frozen section at operation suggested a benign cystadenoma. The cyst was enucleated using a CUSA (Cavitron ultrasonic aspirator). The final histology confirmed endometriosis. Discussion. Eleven cases of hepatic endometrioma have been reported and only four in postmenopausal women. Preoperative diagnosis poses a challenge and so far none of the cases have been diagnosed preoperatively. Surgery remains the treatment of choice. Accurate diagnosis at time of operation may avoid extensive liver surgery and its associated morbidity

    Recursion operator for stationary Nizhnik--Veselov--Novikov equation

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    We present a new general construction of recursion operator from zero curvature representation. Using it, we find a recursion operator for the stationary Nizhnik--Veselov--Novikov equation and present a few low order symmetries generated with the help of this operator.Comment: 6 pages, LaTeX 2
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