9,055 research outputs found

    Grading And Assessments: Correlations Of Variables Affecting Teaching And Course Assessments

    Get PDF
    Faculty assessments are a hot topic in academia. Mostly considered an unproven statistic holding the professor hostage for a good grade, the benefits are still in discussion.  At course end, we expect students to have the ability to analyze what we think they should have learned.  In reality, most students do not have the maturity to realize correlation for what you put into your education is what you get out.  Consensus is that it does not happen the way we plan.  Adding to the assessment issue is the clear fact that today most universities are adjunct professor-driven. Given these facts, the authors have statistically studied teaching assessments and associated grade point averages (GPA) representing academic rigor at a major non-profit university over the past three years.  The authors’ hypothesis is that there is no correlation between the two statistics.  This paper reviews the literature, provides the study methodology, and presents the findings

    Space-Time Foam and Cosmic-Ray Interactions

    Full text link
    It has been proposed that propagation of cosmic rays at extreme-energy may be sensitive to Lorentz-violating metric fluctuations (``foam''). We investigate the changes in interaction thresholds for cosmic-rays and gamma-rays interacting on the CMB and IR backgrounds, for a class of stochastic models of spacetime foam. The strength of the foam is characterized by the factor (E/M_P)^a, where ``a'' is a phenomenological suppression parameter. We find that there exists a critical value of ``a'' (dependent on the particular reaction), below which the threshold energy can only be lowered, and above which the threshold energy may be raised, but at most by a factor of two. Thus, it does not appear possible in this class of models to extend cosmic-ray spectra significantly beyond their classical absorption energies. However, the lower thresholds resulting from foam may have signatures in the cosmic-ray spectrum. We also find that cosmic-ray energies cannot exceed the fundamental Planck scale, and so set a lower bound of 10^8 TeV on the context of this model for the scale of gravity. Finally, we comment in the apparent non-conservation of particle energy-momentum, and speculate on its re-emergence as dark energy in the foamy vacuum.Comment: 27 pages, 13 figures. Author added (Buniy), appendix added, and new section added, corrections made. To appear in Astroparticle Physic

    Observation of coherent delocalized phonon-like modes in DNA under physiological conditions

    Get PDF
    Underdamped terahertz-frequency delocalized phonon-like modes have long been suggested to play a role in the biological function of DNA. Such phonon modes involve the collective motion of many atoms and are prerequisite to understanding the molecular nature of macroscopic conformational changes and related biochemical phenomena. Initial predictions were based on simple theoretical models of DNA. However, such models do not take into account strong interactions with the surrounding water, which is likely to cause phonon modes to be heavily damped and localized. Here we apply state-of-the-art femtosecond optical Kerr effect spectroscopy, which is currently the only technique capable of taking low-frequency (GHz to THz) vibrational spectra in solution. We are able to demonstrate that phonon modes involving the hydrogen bond network between the strands exist in DNA at physiologically relevant conditions. In addition, the dynamics of the solvating water molecules is slowed down by about a factor of 20 compared with the bulk

    A cosmic equation of state for the inhomogeneous Universe: can a global far-from-equilibrium state explain Dark Energy?

    Full text link
    A system of effective Einstein equations for spatially averaged scalar variables of inhomogeneous cosmological models can be solved by providing a `cosmic equation of state'. Recent efforts to explain Dark Energy focus on `backreaction effects' of inhomogeneities on the effective evolution of cosmological parameters in our Hubble volume, avoiding a cosmological constant in the equation of state. In this Letter it is argued that, if kinematical backreaction effects are indeed of the order of the averaged density (or larger as needed for an accelerating domain of the Universe), then the state of our regional Hubble volume would have to be in the vicinity of a far-from-equilibrium state that balances kinematical backreaction and average density. This property, if interpreted globally, is shared by a stationary cosmos with effective equation of state peff=−1/3ρeffp_{\rm eff} = -1/3 \rho_{\rm eff}. It is concluded that a confirmed explanation of Dark Energy by kinematical backreaction may imply a paradigmatic change of cosmology.Comment: 7 pages, matches published version in Class. Quant. Gra

    The Lyman Continuum Escape Survey: Ionizing Radiation from [O III]-Strong Sources at a Redshift of 3.1

    Get PDF
    We present results from the LymAn Continuum Escape Survey (LACES), a Hubble Space Telescope (HST) program designed to characterize the ionizing radiation emerging from a sample of Lyman alpha emitting galaxies at redshift z≃3.1z\simeq 3.1. As many show intense [O III] emission characteristic of z>6.5z>6.5 star-forming galaxies, they may represent valuable low redshift analogs of galaxies in the reionization era. Using HST Wide Field Camera 3 / UVIS F336WF336W to image Lyman continuum emission, we investigate the escape fraction of ionizing photons in this sample. For 61 sources, of which 77% are spectroscopically confirmed and 53 have measures of [O III] emission, we detect Lyman continuum leakage in 20%, a rate significantly higher than is seen in individual continuum-selected Lyman break galaxies. We estimate there is a 98% probability that ≀2\leq 2 of our detections could be affected by foreground contamination. Fitting multi-band spectral energy distributions (SEDs) to take account of the varying stellar populations, dust extinctions and metallicities, we derive individual Lyman continuum escape fractions corrected for foreground intergalactic absorption. We find escape fractions of 15 to 60% for individual objects, and infer an average 20% escape fraction by fitting composite SEDs for our detected samples. Surprisingly however, even a deep stack of those sources with no individual F336WF336W detections provides a stringent upper limit on the average escape fraction of less than 0.5%. We examine various correlations with source properties and discuss the implications in the context of the popular picture that cosmic reionization is driven by such compact, low metallicity star-forming galaxies.Comment: 26 pages, 16 figures, accepted for publication in Ap

    Renewing the Exploration Approach for Mid-Enthalpy Systems: Examples from Northern England and Scotland

    Get PDF
    After a promising start in the 1970s and 80s, the UK rather fell behind other countries in the search for viable mid-enthalpy geothermal resources. This situation began to turn around in 2004, when the first of three deep geothermal exploration boreholes were drilled in northern England. What distinguished these from earlier drilling in Cornwall was the deliberate search for naturallyhigh permeability associated with major faults, especially those that have undergone strike-slip reactivation during the Cenozoic. Boreholes at Eastgate in the North Pennines targeted buried radiothermal granite, whereas the 1,821m-deep Science Central Borehole in Newcastle upon Tyne targeted a postulated deep sedimentary aquifer (the Fell Sandstones), which were inferred to be connected laterally to the granitic heat source by a major fault (the reactivation of the Iapetus geo-suture). The drilling was in both cases rewarded with impressive heat flows, and in the case of Eastgate with what is believed to be the highest permeability yet found in a deep granite batholith anywhere in the world. In parallel with these developments, a re-assessment was made of the preexisting geothermal heat flow database for the UK, applying newly-standardised correction protocols for palaeoclimatic and topographic distortions, which were found to be particularly marked in Scotland (where only shallow boreholes had been used to establish geothermal gradients in the original 1980s analysis), Similar prospects in northern England (similar to that drilled at Science Central) are now the focus of commercial exploration efforts. Appraisal of fault dispositions relative to the present-day maximum compressive stress azimuth are being used to identify the most promising areas for intersecting fault-related permeability at depth. New geophysical tools – most notably atomic dielectric resonance scanning – are also being appraised for their ability to directly detect features (such as hot brines) which are indicative of localised convection in target fault zones and aquifers

    Virginia\u27s Jury Exemptions: Ripe for Reform

    Get PDF
    Jury exemptions are frequent targets of derisory comment. Who among us has not heard of the proverbial litigant who, upon hearing his lawyer describe juries and jury exemptions, remarked that only a fool would place his fate in the hands of seven or twelve people who were not smart enough to get excused through an exemption. Indeed, the number and scope of jury exemptions have grown so substantially over the years that it is not unreasonable to suppose that jury non-service is now the norm and jury service the exception

    Who the hell was that? Stories, bodies and actions in the world

    Get PDF
    This article explores a two-way relationship between stories and the experiential actions of bodies in the world. Through an autoethnographic approach, the article presents a series of interlinked story fragments in an effort to show and evoke a feel for the ways in which stories, bodies, and actions influence and shape each other over time. It offers some reflections on the experiences the stories portray from the perspective of a social constructionist conception of narrative theory and suggest that while stories exert a powerful influence on the actions of our bodies, our bodies intrude on or ‘talk back’ to this process because bodies have an existence beyond stories

    Surreptitious Ingestion of Oral Anticoagulants

    Get PDF
    Hypoprothrombinemia secondary to surreptitious ingestion of coumarin or indanedione anticoagulants may be a difficult diagnosis for the unsuspecting physician. Four such case reports are presented. The disease should be suspected if the prothrombin time is markedly elevated and the individual is associated with the medical profession or has had previous treatment with oral anticoagulants. The diagnosis is confirmed by finding a deficiency in Factors II (prothrombin), VII, IX, and X and the presence of the coumarin or indanedione anticoagulant in the blood. The motive generally is that of gaining attention rather than committing suicide. Liver disease. Vitamin K deficiency states and accidental ingestion of oral anticoagulants are the chief disorders to be considered in the differential diagnosis. Specific assays for the oral anticoagulants are indicated before assuming a rarer etiology for the hemorrhagic syndrome
    • 

    corecore