721 research outputs found

    Adoption of innovative e-learning support for teaching: A multiple case study at the University of Waikato

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    In response to recent social, economic, and pedagogical challenges to tertiary-level teaching and learning, universities are increasingly investigating and adopting elearning as a way to engage and motivate students. This paper reports on the first year of a two-year (2009-2010) qualitative multiple case study research project in New Zealand. Using perspectives from activity theory and the scholarship of teaching, the research has the overall goal of documenting, developing, and disseminating effective and innovative practice in which e-learning plays an important role in tertiary teaching. A “snapshot” of each of the four 2009 cases and focused findings within and across cases are provided. This is followed by an overall discussion of the context, “within” and “across” case themes, and implications of the research

    Training in laparoscopic colorectal surgery: A new educational model using specially embalmed human anatomical specimen

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    Background: With an increasing percentage of colorectal resections performed laparoscopically nowadays, there is more emphasis on training "before the job" on operative skills, including the comprehension of specific laparoscopic surgical anatomy. As integration of technical skills with correct interpretation of the anatomical image must be incorporated in laparoscopic training, a human specimen training model with special emphasis on surgical anatomy was developed. Methods: The new embalming method Anubifix ™ combines long-term high-quality embalming of human bodies with almost normal flexibility and plasticity, and the body can be kept operational as long as conventionally embalmed human specimens. A colorectal training model was created in a specimen in which anatomical landmarks of colorectal anatomy were permanently colored to explore laparoscopic colorectal anatomy in a skills training setting. Airtight closure of the abdominal wall permits the creation of pneumoperitoneum. Residents were asked to test the model by mobilizing the small and large bowels and expose the central vessels and ureters. Afterward they were asked to fill out an eight-item questionnaire about the model. Results: Eleven surgical residents in their first and second year of training participated. Responses to the questionnaire showed that a majority of residents considered the model to be representative of the real situation and superior to animal models or virtual reality simulators, and helped to improve the knowledge of three-dimensional anatomy and laparoscopic skills. Conclusion The new training model for laparoscopic colorectal: surgery proved to be a high-quality tool, concentrating on laparoscopic colorectal anatomy in a skills training setting. We believe it may be a valuable adjunct to residency training programs based on the principle of "trainin

    Vacuum Bubbles Nucleation and Dark Matter Production through Gauge Symmetry Rearrangement

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    Modern particle physics and cosmology support the idea that a background of invisible material pervades the whole universe, and identify in the cosmic vacuum the ultimate source of matter-energy, both seen and unseen. Within the framework of the theory of fundamental relativistic membranes, we suggest a self-consistent, vacuum energy-driven mechanism for dark matter creation through gauge symmetry rearrangement.Comment: 22pages, RevTeX, no figures; accepted for publication in Phys.Rev.

    Precision Pion-Proton Elastic Differential Cross Sections at Energies Spanning the Delta Resonance

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    A precision measurement of absolute pi+p and pi-p elastic differential cross sections at incident pion laboratory kinetic energies from T_pi= 141.15 to 267.3 MeV is described. Data were obtained detecting the scattered pion and recoil proton in coincidence at 12 laboratory pion angles from 55 to 155 degrees for pi+p, and six angles from 60 to 155 degrees for pi-p. Single arm measurements were also obtained for pi+p energies up to 218.1 MeV, with the scattered pi+ detected at six angles from 20 to 70 degrees. A flat-walled, super-cooled liquid hydrogen target as well as solid CH2 targets were used. The data are characterized by small uncertainties, ~1-2% statistical and ~1-1.5% normalization. The reliability of the cross section results was ensured by carrying out the measurements under a variety of experimental conditions to identify and quantify the sources of instrumental uncertainty. Our lowest and highest energy data are consistent with overlapping results from TRIUMF and LAMPF. In general, the Virginia Polytechnic Institute SM95 partial wave analysis solution describes our data well, but the older Karlsruhe-Helsinki PWA solution KH80 does not.Comment: 39 pages, 22 figures (some with quality reduced to satisfy ArXiv requirements. Contact M.M. Pavan for originals). Submitted to Physical Review

    Azimuthal anisotropy and correlations in p+p, d+Au and Au+Au collisions at 200 GeV

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    We present the first measurement of directed flow (v1v_1) at RHIC. v1v_1 is found to be consistent with zero at pseudorapidities η\eta from -1.2 to 1.2, then rises to the level of a couple of percent over the range 2.4<η<42.4 < |\eta| < 4. The latter observation is similar to data from NA49 if the SPS rapidities are shifted by the difference in beam rapidity between RHIC and SPS. Back-to-back jets emitted out-of-plane are found to be suppressed more if compared to those emitted in-plane, which is consistent with {\it jet quenching}. Using the scalar product method, we systematically compared azimuthal correlations from p+p, d+Au and Au+Au collisions. Flow and non-flow from these three different collision systems are discussed.Comment: Quark Matter 2004 proceeding, 4 pages, 3 figure

    Azimuthal anisotropy: the higher harmonics

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    We report the first observations of the fourth harmonic (v_4) in the azimuthal distribution of particles at RHIC. The measurement was done taking advantage of the large elliptic flow generated at RHIC. The integrated v_4 is about a factor of 10 smaller than v_2. For the sixth (v_6) and eighth (v_8) harmonics upper limits on the magnitudes are reported.Comment: 4 pages, 6 figures, contribution to the Quark Matter 2004 proceeding

    Partonic flow and ϕ\phi-meson production in Au+Au collisions at sNN\sqrt{s_{NN}} = 200 GeV

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    We present first measurements of the ϕ\phi-meson elliptic flow (v2(pT)v_{2}(p_{T})) and high statistics pTp_{T} distributions for different centralities from sNN\sqrt{s_{NN}} = 200 GeV Au+Au collisions at RHIC. In minimum bias collisions the v2v_{2} of the ϕ\phi meson is consistent with the trend observed for mesons. The ratio of the yields of the Ω\Omega to those of the ϕ\phi as a function of transverse momentum is consistent with a model based on the recombination of thermal ss quarks up to pT4p_{T}\sim 4 GeV/cc, but disagrees at higher momenta. The nuclear modification factor (RCPR_{CP}) of ϕ\phi follows the trend observed in the KS0K^{0}_{S} mesons rather than in Λ\Lambda baryons, supporting baryon-meson scaling. Since ϕ\phi-mesons are made via coalescence of seemingly thermalized ss quarks in central Au+Au collisions, the observations imply hot and dense matter with partonic collectivity has been formed at RHIC.Comment: 6 pages, 4 figures, submit to PR

    Plasma Wakefield Acceleration with a Modulated Proton Bunch

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    The plasma wakefield amplitudes which could be achieved via the modulation of a long proton bunch are investigated. We find that in the limit of long bunches compared to the plasma wavelength, the strength of the accelerating fields is directly proportional to the number of particles in the drive bunch and inversely proportional to the square of the transverse bunch size. The scaling laws were tested and verified in detailed simulations using parameters of existing proton accelerators, and large electric fields were achieved, reaching 1 GV/m for LHC bunches. Energy gains for test electrons beyond 6 TeV were found in this case.Comment: 9 pages, 7 figure

    The energy dependence of ptp_t angular correlations inferred from mean-ptp_{t} fluctuation scale dependence in heavy ion collisions at the SPS and RHIC

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    We present the first study of the energy dependence of ptp_t angular correlations inferred from event-wise mean transverse momentum fluctuations in heavy ion collisions. We compare our large-acceptance measurements at CM energies $\sqrt{s_{NN}} =$ 19.6, 62.4, 130 and 200 GeV to SPS measurements at 12.3 and 17.3 GeV. $p_t$ angular correlation structure suggests that the principal source of $p_t$ correlations and fluctuations is minijets (minimum-bias parton fragments). We observe a dramatic increase in correlations and fluctuations from SPS to RHIC energies, increasing linearly with $\ln \sqrt{s_{NN}}$ from the onset of observable jet-related fluctuations near 10 GeV.Comment: 10 pages, 4 figure

    All-optical switching and strong coupling using tunable whispering-gallery-mode microresonators

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    We review our recent work on tunable, ultrahigh quality factor whispering-gallery-mode bottle microresonators and highlight their applications in nonlinear optics and in quantum optics experiments. Our resonators combine ultra-high quality factors of up to Q = 3.6 \times 10^8, a small mode volume, and near-lossless fiber coupling, with a simple and customizable mode structure enabling full tunability. We study, theoretically and experimentally, nonlinear all-optical switching via the Kerr effect when the resonator is operated in an add-drop configuration. This allows us to optically route a single-wavelength cw optical signal between two fiber ports with high efficiency. Finally, we report on progress towards strong coupling of single rubidium atoms to an ultra-high Q mode of an actively stabilized bottle microresonator.Comment: 20 pages, 24 figures. Accepted for publication in Applied Physics B. Changes according to referee suggestions: minor corrections to some figures and captions, clarification of some points in the text, added references, added new paragraph with results on atom-resonator interactio
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