Journalistic Codes of Ethics: A Proposed Standard for Juries in Libel Trials

The standard of judgment for determining fault in tort law as applied to libel is ambiguous. Juries are allowed to rule against media defendants by using a standard that does not consider professional journalistic practice. I argue that the determination of professional fault is beyond the understanding of a lay jury due to the unique professional practice of journalists. Juries find it far easier to empathize with private party plaintiffs than with media defendants. I abstract criteria from standards of conduct for the journalism profession and determine what the reasonable journalist might do in general practice. In conclusion, I offer suggestions for the implementation of these criteria as a solution to the current legal dilemma

Basin structure of optimization based state and parameter estimation

Most data based state and parameter estimation methods require suitable initial values or guesses to achieve convergence to the desired solution, which typically is a global minimum of some cost function. Unfortunately, however, other stable solutions (e.g., local minima) may exist and provide suboptimal or even wrong estimates. Here we demonstrate for a 9-dimensional Lorenz-96 model how to characterize the basin size of the global minimum when applying some particular optimization based estimation algorithm. We compare three different strategies for generating suitable initial guesses and we investigate the dependence of the solution on the given trajectory segment (underlying the measured time series). To address the question of how many state variables have to be measured for optimal performance, different types of multivariate time series are considered consisting of 1, 2, or 3 variables. Based on these time series the local observability of state variables and parameters of the Lorenz-96 model is investigated and confirmed using delay coordinates. This result is in good agreement with the observation that correct state and parameter estimation results are obtained if the optimization algorithm is initialized with initial guesses close to the true solution. In contrast, initialization with other exact solutions of the model equations (different from the true solution used to generate the time series) typically fails, i.e. the optimization procedure ends up in local minima different from the true solution. Initialization using random values in a box around the attractor exhibits success rates depending on the number of observables and the available time series (trajectory segment).Comment: 15 pages, 2 figure

Use of Raman Spectroscopy and Delta Volume Growth from Void Collapse to Assess Overwrap Stress Gradients Compromising the Reliability of Large Kevlar/Epoxy COPVs

Composite Overwrapped Pressure Vessels (COPVs) are frequently used for storing pressurized gases aboard spacecraft and aircraft when weight saving is desirable compared to all-metal versions. Failure mechanisms in fibrous COPVs and variability in lifetime can be very different from their metallic counterparts; in the former, catastrophic stress-rupture can occur with virtually no warning, whereas in latter, a leak before burst design philosophy can be implemented. Qualification and certification typically requires only one burst test on a production sample (possibly after several pressure cycles) and the vessel need only meet a design burst strength (the maximum operating pressure divided by a knockdown factor). Typically there is no requirement to assess variability in burst strength or lifetime, much less determine production and materials processing parameters important to control of such variability. Characterizing such variability and its source is crucial to models for calculating required reliability over a given lifetime (e.g. R = 0.9999 for 15 years). In this paper we present a case study of how lack of control of certain process parameters in COPV manufacturing can result in variations among vessels and between production runs that can greatly increase uncertainty and reduce reliability. The vessels considered are 40-inch ( NASA Glenn Research center, Cleveland, OH, 44135 29,500 in3 ) spherical COPVs with a 0.74 in. thick Kevlar49/epoxy overwrap and with a titanium liner of which 34 were originally produced. Two burst tests were eventually performed that unexpectedly differed by almost 5%, and were 10% lower than anticipated from burst tests on 26-inch sister vessels similar in every detail. A major observation from measurements made during proof testing (autofrettage) of the 40-inch vessels was that permanent volume growth from liner yielding varied by a factor of more than two (150 in3 to 360 in3 ), which suggests large differences in the residual stress gradient through their overwraps. This resulted in large uncertainty in true fiber stress ratio (fiber stress at operating pressure divided by fiber stress at burst) which governs lifetime. The vessels were originally designed with tight safety margins, so it became crucial to develop a non-destructive evaluation (NDE) technique to directly measure the overwrap residual stress state of each vessel, and to identify those vessels at highest risk of having poor reliability. This paper describes a Raman Spectroscopy technique for measuring certain patterns of fluctuation in fiber elastic strains over the outside vessel surface (where all but one wrap is exposed at certain locations) that are shown to directly correlate to increased fiber stress ratios and reduced reliability

Casino Capers: Exploring the Aesthetics of Superfluidity

Casinos are fast becoming sites for display of new Native American (NA) Arts. In such a context, casinos re-represent themselves and their communities through various visual forms and thus change their meanings. In her study of Wisconsin casinos, Stuhr (2004) challenged art educators to consider these visual culture displays as they accommodate new markets. Art in the casino phenomenon is worth investigating and how art educators can explore and/or make sense of this phenomenon is important. Casinos are using artworks as spectacles of pleasure. According to a casino gambling survey conducted by Harrah’s Entertainment, approximately 40 million Americans played slot machines in 2003 (Rivlin, 2004). People are attracted to the glitz and the chance of winning money. Such things are phenomenal— highly sensual and impressive, and there lies the attraction. The gambling experience dates back at least to the casting of lots in the Bible. Experience always has an aesthetic component. An aesthetic experience resides not so much in a thing’s appearance, as in its life-like substitutes. “In an age in which desire is inculcated even in those who have nothing to buy, the metropolis [casino] becomes the place where the superfluity of objects is converted into a value in and of itself” (Mbembe, 2004, p. 405). So what aesthetic qualities draw people to the casino

Collaborative Faculty Professional Development: Bringing the Classroom to the Screen

When the higher education practice of face-to-face instruction was disrupted by the COVID pandemic, faculty unaccustomed to and/or uncomfortable with online teaching needed to adapt quickly to serve their students. Fortunately, there are faculty and institutions with long histories of online teaching with much to share about the why and how of offering high-quality, deeply engaging digital learning experiences to support the success of higher education students. The paper explores the collaboration of two universities to create professional development delivered through a virtual workshop series to support faculty needs and encourage an emerging community of practice related to online teaching and learning, jointly envisioned and delivered with pilot funding from the Bill and Melinda Gates Foundation. Four key issues conclude the paper: (1) how can success be measured and supported, (2) how can emerging practices be disseminated beyond workshop participants, (3) how can we respond to the need for changes in how we recognize, incentivize, and reward good teaching, and (4) how do we move forward from here

Spin-orbit fields in asymmetric (001)-oriented GaAs/AlxGa 1-xAs quantum wells

We measure simultaneously the in-plane electron g factor and spin-relaxation rate in a series of undoped inversion-asymmetric (001)-oriented GaAs/AlGaAs quantum wells by spin-quantum beat spectroscopy. In combination the two quantities reveal the absolute values of both the Rashba and the Dresselhaus coefficients and prove that the Rashba coefficient can be negligibly small despite huge conduction-band potential gradients which break the inversion symmetry. The negligible Rashba coefficient is a consequence of the "isomorphism" of conduction- and valence-band potentials in quantum systems where the asymmetry is solely produced by alloy variations. © 2011 American Physical Society

Strain-induced spin relaxation anisotropy in symmetric (001)-oriented GaAs quantum wells

We show experimentally, using spin quantum beat spectroscopy, that strain applied to an undoped symmetric (001) GaAs/AlGaAs multiple quantum well causes an in-plane anisotropy of the spin-relaxation rate Γs, but leaves the electron Landé g factor isotropic. The spin-relaxation-rate anisotropy gives a direct measure of the bulk inversion asymmetry and the strain contributions to the conduction-band spin splitting. The comparison of the measured strain-splitting coefficient C3 for the quantum well with the value for bulk GaAs suggests a dependence on electron quantum confinement. The isotropic g factor implies a symmetric conduction electron wave function, whereas the anisotropic spin-relaxation rate requires a nonzero expectation value of the valence-band potential gradient on the conduction-band states. Therefore, the experiment suggests that strain generates an effective valence-band potential gradient, while the conduction-band potential remains symmetrical to a good approximation. © 2011 American Physical Society

Effect of symmetry reduction on the spin dynamics of (001)-oriented GaAs quantum wells

Spin quantum beat spectroscopy is employed to investigate the in-plane anisotropy of the spin dynamics in (001) GaAs/AlGaAs quantum wells induced by an external electric field. This technique allows the anisotropy of the spin relaxation rate Γs and the electron Landé g factor g* to be measured simultaneously. The measurements are compared to similar data from (001) GaAs/AlGaAs quantum wells with applied shear strain and asymmetric barrier growth. All of these operations act to reduce the symmetry compared to that of a symmetric (001) quantum well in an identical manner (D2d → C2v). However, by looking at the anisotropy of both Γs and g* simultaneously we show that the microscopic actions of these symmetry breaking operations are very different. The experiments attest that although symmetry arguments are a very useful tool to identify the allowed spin dependent properties of a material system, only a microscopic approach reveals if allowed anisotropies will manifest. © 2013 American Physical Society