9,055 research outputs found
Grading And Assessments: Correlations Of Variables Affecting Teaching And Course Assessments
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 authorsâ 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
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
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?
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 . 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
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 . As many show intense [O III] emission characteristic of
star-forming galaxies, they may represent valuable low redshift analogs of
galaxies in the reionization era. Using HST Wide Field Camera 3 / UVIS
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 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 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
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 â most notably atomic dielectric resonance scanning â 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
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
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 âtalk backâ to this process because bodies have an existence beyond stories
Surreptitious Ingestion of Oral Anticoagulants
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
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