172 research outputs found
Using Interactive Engagement Strategies to Enhance Learning in College Science Courses
The number of decreasing science majors in U.S. institutions of higher education is connected to the quality of science instruction (Seymour, 1994; Daempfle, 2003) and resulted in nation-wide efforts to improve the quality of college-level science education (National Committee on Science Education Standards and Assessment et al., 1996; NGSS Lead States, 2013). This talk presents historical trends in the adoption of interactive engagement (IE) strategies in college-level science courses and presents one such IE strategy, lecture tutorials (LTs), in the context of sedimentology and stratigraphy.
To determine historical trends in the adoption of IE strategies, peer-reviewed journal articles accessible via the Education Resources Information Center (ERIC) reviewed for the period of 1994-2014. The review reveals growth in IE strategy adoption, especially in the field of Biology. Five distinct types of IE strategies emerged from the literature review: polling, whole-class discussion and activities, in-class group work, out-of-class group work, and online activities. One form of in-class group work includes LTs, which are designed to improve students’ conceptual understanding. To identify weaknesses in students’ conceptual understanding of sedimentology and stratigraphy, geoscience instructors at institutions of higher education across the U.S. were surveyed. Four LTs were designed to address the identified weaknesses and tested using a quasi-experimental design, which compared the learning gains of a control group (lecture-only) with a treatment group (lecture-and-LT). Three of the four LTs produced significant learning gains above the lecture-only scenarios.
IE strategies developed in one discipline (e.g., LTs were initially developed in Physics) offer potential for their transferability to other disciplines. Although the disciplinary content and context will necessarily change, the overriding design and implementation principles developed in one discipline provide a jump start for the creation of curricular materials for similar IE strategies in other disciplines
Characterizing Quantum Microwave Radiation and its Entanglement with Superconducting Qubits using Linear Detectors
Recent progress in the development of superconducting circuits has enabled
the realization of interesting sources of nonclassical radiation at microwave
frequencies. Here, we discuss field quadrature detection schemes for the
experimental characterization of itinerant microwave photon fields and their
entanglement correlations with stationary qubits. In particular, we present
joint state tomography methods of a radiation field mode and a two-level
system. Including the case of finite quantum detection efficiency, we relate
measured photon field statistics to generalized quasi-probability distributions
and statistical moments for one-channel and two-channel detection. We also
present maximum-likelihood methods to reconstruct density matrices from
measured field quadrature histograms. Our theoretical investigations are
supported by the presentation of experimental data, for which microwave quantum
fields beyond the single-photon and Gaussian level have been prepared and
reconstructed.Comment: 14 pages, 5 figure
Quantum Communication with Correlated Nonclassical States
Nonclassical correlations between the quadrature-phase amplitudes of two
spatially separated optical beams are exploited to realize a two-channel
quantum communication experiment with a high degree of immunity to
interception. For this scheme, either channel alone can have an arbitrarily
small signal-to-noise ratio (SNR) for transmission of a coherent ``message''.
However, when the transmitted beams are combined properly upon authorized
detection, the encoded message can in principle be recovered with the original
SNR of the source. An experimental demonstration has achieved a 3.2 dB
improvement in SNR over that possible with correlated classical sources.
Extensions of the protocol to improve its security against eavesdropping are
discussed.Comment: 8 pages and 4 figures (Figure 1; Figures 2a, 2b; Figure 2
Chaste: an open source C++ library for computational physiology and biology
Chaste - Cancer, Heart And Soft Tissue Environment - is an open source C++ library for the computational simulation of mathematical models developed for physiology and biology. Code development has been driven by two initial applications: cardiac electrophysiology and cancer development. A large number of cardiac electrophysiology studies have been enabled and performed, including high performance computational investigations of defibrillation on realistic human cardiac geometries. New models for the initiation and growth of tumours have been developed. In particular, cell-based simulations have provided novel insight into the role of stem cells in the colorectal crypt. Chaste is constantly evolving and is now being applied to a far wider range of problems. The code provides modules for handling common scientific computing components, such as meshes and solvers for ordinary and partial differential equations (ODEs/PDEs). Re-use of these components avoids the need for researchers to "re-invent the wheel" with each new project, accelerating the rate of progress in new applications. Chaste is developed using industrially-derived techniques, in particular test-driven development, to ensure code quality, re-use and reliability. In this article we provide examples that illustrate the types of problems Chaste can be used to solve, which can be run on a desktop computer. We highlight some scientific studies that have used or are using Chaste, and the insights they have provided. The source code, both for specific releases and the development version, is available to download under an open source Berkeley Software Distribution (BSD) licence at http://www.cs.ox.ac.uk/chaste, together with details of a mailing list and links to documentation and tutorials
Broadband teleportation
Quantum teleportation of an unknown broadband electromagnetic field is
investigated. The continuous-variable teleportation protocol by Braunstein and
Kimble [Phys. Rev. Lett. {\bf 80}, 869 (1998)] for teleporting the quantum
state of a single mode of the electromagnetic field is generalized for the case
of a multimode field with finite bandwith. We discuss criteria for
continuous-variable teleportation with various sets of input states and apply
them to the teleportation of broadband fields. We first consider as a set of
input fields (from which an independent state preparer draws the inputs to be
teleported) arbitrary pure Gaussian states with unknown coherent amplitude
(squeezed or coherent states). This set of input states, further restricted to
an alphabet of coherent states, was used in the experiment by Furusawa {\it et
al.} [Science {\bf 282}, 706 (1998)]. It requires unit-gain teleportation for
optimizing the teleportation fidelity. In our broadband scheme, the excess
noise added through unit-gain teleportation due to the finite degree of the
squeezed-state entanglement is just twice the (entanglement) source's squeezing
spectrum for its ``quiet quadrature.'' The teleportation of one half of an
entangled state (two-mode squeezed vacuum state), i.e., ``entanglement
swapping,'' and its verification are optimized under a certain nonunit gain
condition. We will also give a broadband description of this
continuous-variable entanglement swapping based on the single-mode scheme by
van Loock and Braunstein [Phys. Rev. A {\bf 61}, 10302 (2000)]Comment: 27 pages, 7 figures, revised version for publication, Physical Review
A (August 2000); major changes, in parts rewritte
Quantum information with continuous variables
Quantum information is a rapidly advancing area of interdisciplinary
research. It may lead to real-world applications for communication and
computation unavailable without the exploitation of quantum properties such as
nonorthogonality or entanglement. We review the progress in quantum information
based on continuous quantum variables, with emphasis on quantum optical
implementations in terms of the quadrature amplitudes of the electromagnetic
field.Comment: accepted for publication in Reviews of Modern Physic
Admission hypo- or hyperthermia and survival after trauma in civilian and military environments
Dealing with the mess (we made): Unraveling hybridity, normativity, and complexity in journalism studies
In this article, we discuss the rise and use of the concept of hybridity in journalism studies. Hybridity afforded a meaningful intervention in a discipline that had the tendency to focus on a stabilized and homogeneous understanding of the field. Nonetheless, we now need to reconsider its deployment, as it only partially allows us to address and understand the developments in journalism. We argue that if scholarship is to move forward in a productive manner, we need, rather than denote everything that is complex as hybrid, to develop new approaches to our object of study. Ultimately, this is an open invitation to the field to adopt experientialist, practice-based approaches that help us overcome the ultimately limited binary dualities that have long governed our theoretical and empirical work in the field
Identification of Radiopure Titanium for the LZ Dark Matter Experiment and Future Rare Event Searches
The LUX-ZEPLIN (LZ) experiment will search for dark matter particle
interactions with a detector containing a total of 10 tonnes of liquid xenon
within a double-vessel cryostat. The large mass and proximity of the cryostat
to the active detector volume demand the use of material with extremely low
intrinsic radioactivity. We report on the radioassay campaign conducted to
identify suitable metals, the determination of factors limiting radiopure
production, and the selection of titanium for construction of the LZ cryostat
and other detector components. This titanium has been measured with activities
of U~1.6~mBq/kg, U~0.09~mBq/kg,
Th~~mBq/kg, Th~~mBq/kg, K~0.54~mBq/kg, and Co~0.02~mBq/kg (68\% CL).
Such low intrinsic activities, which are some of the lowest ever reported for
titanium, enable its use for future dark matter and other rare event searches.
Monte Carlo simulations have been performed to assess the expected background
contribution from the LZ cryostat with this radioactivity. In 1,000 days of
WIMP search exposure of a 5.6-tonne fiducial mass, the cryostat will contribute
only a mean background of (stat)(sys) counts.Comment: 13 pages, 3 figures, accepted for publication in Astroparticle
Physic
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