An LED pulser for measuring photomultiplier linearity

A light-emitting diode (LED) pulser for testing the low-rate response of a photomultiplier tube (PMT) to scintillator-like pulses has been designed, developed, and implemented. This pulser is intended to simulate 80 ns full width at half maximum photon pulses over the dynamic range of the PMT, in order to precisely determine PMT linearity. This particular design has the advantage that, unlike many LED test rigs, it does not require the use of multiple calibrated LEDs, making it insensitive to LED gain drifts. Instead, a finite-difference measurement is made using two LEDs which need not be calibrated with respect to one another. These measurements give a better than 1% mapping of the response function, allowing for the testing and development of particularly linear PMT bases.Comment: 5 pages, 5 figure

Designing contests between heterogeneous contestants: An experimental study of tie-breaks and bid-caps in all-pay auctions

A well-known theoretical result in the contest literature is that greater heterogeneity decreases performance of contestants because of the “discouragement effect.” Leveling the playing field by favoring weaker contestants through bid-caps and favorable tie-breaking rules can reduce the discouragement effect and increase the designer’s revenue. We test these predictions in an experiment. Our data show that indeed, strengthening weaker contestants through tie-breaks and bid-caps significantly diminishes the iscouragement effect. Bid-caps can also improve revenue. Most deviations from Nash equilibrium can be explained by the level-k model of reasoning

Designing contests between heterogeneous contestants: An experimental study of tie-breaks and bid-caps in all-pay auctions

A well-known theoretical result in the contest literature is that greater heterogeneity decreases investments of contestants because of the “discouragement effect.” Levelling the playing field by favouring weaker contestants through strict bid-caps and favourable tie-breaking rules can reduce discouragement and increase the designer\u27s revenue. We test these predictions in a laboratory experiment. Our data confirm that placing bid-caps and using favourable tie-breaking rules significantly diminishes discouragement of weaker contestants. However, its impact on revenues is muted by the fact that the encouragement of weaker contestants is offset by stronger contestants competing less aggressively, even when not predicted by theory. We discuss deviations from the Nash predictions in light of different behavioural approaches

Strangeness and Chiral Symmetry Breaking

The implications of chiral symmetry breaking and SU(3) symmetry breaking have been studied in the chiral constituent quark model ($\chi$CQM). The role of hidden strangeness component has been investigated for the scalar matrix elements of the nucleon with an emphasis on the meson-nucleon sigma terms. The $\chi$CQM is able to give a qualitative and quantitative description of the "quark sea" generation through chiral symmetry breaking. The significant contribution of the strangeness is consistent with the recent available experimental observations.Comment: 10 pages, 1 table. To appear in Mod. Phys. Lett.

Nurses Forming Legal Partnerships to Meet the Needs of the Underserved in Rural America

The impetus for the recognition of the need for legal partners in healthcare came from Boston City Hospital in 1993. The hospital provided care to the largest uninsured and underinsured population in the New England states. The pediatric patients were noted by Dr. Barry Zuckerman to have difficulty in recovering from medical illnesses. He linked their inability to improve their health to poor housing, food insecurity, and basic social determinants of health. His hiring of a part-time lawyer led to a national movement for the development of medical-legal partnerships. The American Bar Association, the National Center for Medical-Legal Partnerships at George Washington University in Washington, DC and the American Academy of Pediatrics formed the first national medical-legal partnership in 2007. Joint resolutions were passed for members to become partners with the other professional colleagues to “address the legal and social issues affecting patient health and well-being.” The American Bar Association resolution led to the creation of the Medical-Legal Partnership Pro Bono Project. In 2015, the East Tennessee State University College of Nursing nurse-led community health center was awarded a small grant from the National Nurse Centers Consortium to participate in the development of a medical-legal partnership. The health center is staffed by Nurse Practitioners who provide health care for the underserved in northeast Tennessee. The patients are diverse and include homeless, migrants, residents of public housing, uninsured, and underinsured. Partnering with the Tennessee Justice Center in Nashville, Tennessee, the nurse-led medical legal partnership improved lives of pediatric patients, adults, pregnant women across the state, and advocacy rights for those who cannot speak for themselves

The 2008 August 1 Eclipse Solar-Minimum Corona Unraveled

We discuss results stemming from observations of the white-light and [Fe XIV] emission corona during the total eclipse of the Sun of 2008 August 1, in Mongolia (Altaj region) and in Russia (Akademgorodok, Novosibirsk, Siberia). Corresponding to the current extreme solar minimum, the white-light corona, visible up to 20 solar radii, was of a transient type with well-pronounced helmet streamers situated above a chain of prominences at position angles 48, 130, 241 and 322 degrees. A variety of coronal holes, filled with a number of thin polar plumes, were seen around the poles. Furthering an original method of image processing, stars up to 12 magnitude, a Kreutz-group comet (C/2008 O1), and a coronal mass ejection (CME) were also detected, with the smallest resolvable structures being of, and at some places even less than, 1 arcsec. Differences, presumably motions, in the corona and prominences are seen even with the 19-min time difference between our sites. In addition to the high-resolution coronal images, which show the continuum corona (K-corona) that results from electron scattering of photospheric light, images of the overlapping green-emission-line (530.3 nm, [Fe XIV]) corona were obtained with the help of two narrow-passband filters (centered on the line itself and for the continuum in the vicinity of 529.1 nm, respectively), each with FWHM of 0.15 nm. Through solar observations, on whose scheduling and details we consulted, with the Solar and Heliospheric Observatory, Hinode's XRT and SOT, TRACE, and STEREO, as well as Wilcox Solar Observatory and SOHO/MDI magnetograms, we set our eclipse observations in the context of the current unusually low and prolonged solar minimum.Comment: Accepted in The Astrophysical Journal, 6 July 200

Preliminary Results from Integrating Compton Photon Polarimetry in Hall A of Jefferson Lab

A wide range of nucleon and nuclear structure experiments in Jefferson Lab's Hall A require precise, continuous measurements of the polarization of the electron beam. In our Compton polarimeter, electrons are scattered off photons in a Fabry-Perot cavity; by measuring an asymmetry in the integrated signal of the scattered photons detected in a GSO crystal, we can make non-invasive, continuous measurements of the beam polarization. Our goal is to achieve 1% statistical error within two hours of running. We discuss the design and commissioning of an upgrade to this apparatus, and report preliminary results for experiments conducted at beam energies from 3.5 to 5.9 GeV and photon rates from 5 to 100 kHz.Comment: 6 pages, 7 figures. To appear in the Proceedings of the International Nuclear Physics Conference (INPC 2010), July 4-9 2010, Vancouver, Canada (Journal of Physics: Conference Series