String Breaking in Four Dimensional Lattice QCD

Virtual quark pair screening leads to breaking of the string between fundamental representation quarks in QCD. For unquenched four dimensional lattice QCD, this (so far elusive) phenomenon is studied using the recently developed truncated determinant algorithm (TDA). The dynamical configurations were generated on an Athlon 650 MHz PC. Quark eigenmodes up to 420 MeV are included exactly in these TDA studies performed at low quark mass on large coarse (but O($a^2$) improved) lattices. A study of Wilson line correlators in Coulomb gauge extracted from an ensemble of 1000 two-flavor dynamical configurations reveals evidence for flattening of the string tension at distances R $\geq$ approximately 1 fm.Comment: 16 pages, 5 figures, Latex (deleted extraneous eps figure file

Pariah moonshine

Finite simple groups are the building blocks of finite symmetry. The effort to classify them precipitated the discovery of new examples, including the monster, and six pariah groups which do not belong to any of the natural families, and are not involved in the monster. It also precipitated monstrous moonshine, which is an appearance of monster symmetry in number theory that catalysed developments in mathematics and physics. Forty years ago the pioneers of moonshine asked if there is anything similar for pariahs. Here we report on a solution to this problem that reveals the O'Nan pariah group as a source of hidden symmetry in quadratic forms and elliptic curves. Using this we prove congruences for class numbers, and Selmer groups and Tate--Shafarevich groups of elliptic curves. This demonstrates that pariah groups play a role in some of the deepest problems in mathematics, and represents an appearance of pariah groups in nature.Comment: 20 page

Accountability, Information and Communications Systems (AICS): Washington’s Approach to Accountability Reporting

This article describes AICS, a flexible, multi-purpose, Web-based Accountability, Information and Communications System developed by the College of Agriculture and Home Economics at Washington State University. Made up of more than 200 programs, the system collects, stores and retrieves information from faculty, regardless of appointment and specified staff. AICS’s single, standardized, reporting format supersedes previous annual faculty activity reports, which varied from department to department. The searchable database provides information for a wide variety of reporting needs, including accountability. Developed between 1998 and 1999, the system was implemented at the end of 1999. Ohio State University, Purdue University, Kansas State University and the University of Missouri have since purchased the software to adapt for their use. Kathleen Duncan has conducted workshops for each of these institutions. Ohio state University is currently using the system (http://www.oardc.ohio-state.edu/ursdevell/accountability/); the systems personnel at the other three universities expect to have the system in use by Fall 2001 (personal communication, April 26, 2001)

Quantum Dynamics of the Slow Rollover Transition in the Linear Delta Expansion

We apply the linear delta expansion to the quantum mechanical version of the slow rollover transition which is an important feature of inflationary models of the early universe. The method, which goes beyond the Gaussian approximation, gives results which stay close to the exact solution for longer than previous methods. It provides a promising basis for extension to a full field theoretic treatment.Comment: 12 pages, including 4 figure

Independent component analysis of interictal fMRI in focal epilepsy: comparison with general linear model-based EEG-correlated fMRI

The general linear model (GLM) has been used to analyze simultaneous EEG–fMRI to reveal BOLD changes linked to interictal epileptic discharges (IED) identified on scalp EEG. This approach is ineffective when IED are not evident in the EEG. Data-driven fMRI analysis techniques that do not require an EEG derived model may offer a solution in these circumstances. We compared the findings of independent components analysis (ICA) and EEG-based GLM analyses of fMRI data from eight patients with focal epilepsy. Spatial ICA was used to extract independent components (IC) which were automatically classified as either BOLD-related, motion artefacts, EPI-susceptibility artefacts, large blood vessels, noise at high spatial or temporal frequency. The classifier reduced the number of candidate IC by 78%, with an average of 16 BOLD-related IC. Concordance between the ICA and GLM-derived results was assessed based on spatio-temporal criteria. In each patient, one of the IC satisfied the criteria to correspond to IED-based GLM result. The remaining IC were consistent with BOLD patterns of spontaneous brain activity and may include epileptic activity that was not evident on the scalp EEG. In conclusion, ICA of fMRI is capable of revealing areas of epileptic activity in patients with focal epilepsy and may be useful for the analysis of EEG–fMRI data in which abnormalities are not apparent on scalp EEG

Unquenched QCD with Light Quarks

We present recent results in unquenched lattice QCD with two degenerate light sea quarks using the truncated determinant approximation (TDA). In the TDA the infrared modes contributing to the quark determinant are computed exactly up to some cutoff in quark off-shellness (typically 2$\Lambda_{QCD}$). This approach allows simulations to be performed at much lighter quark masses than possible with conventional hybrid MonteCarlo techniques. Results for the static energy and topological charge distributions are presented using a large ensemble generated on very coarse (6$^4$) but physically large lattices. Preliminary results are also reported for the static energy and meson spectrum on 10$^3$x20 lattices (lattice scale $a^{-1}$=1.15 GeV) at quark masses corresponding to pions of mass $\leq$ 200 MeV. Using multiboson simulation to compute the ultraviolet part of the quark determinant the TDA approach becomes an exact with essentially no increase in computational effort. Some preliminary results using this fully unquenched algorithm are presented.Comment: LateX, 39 pages, 16 eps figures, 1 ps figur

On the Spin History of the X-ray Pulsar in Kes 73: Further Evidence For an Utramagnetized Neutron Star

In previous papers, we presented the discovery of a 12-s X-ray pulsar in the supernova remnant Kes 73, providing the first direct evidence for an ultramagnetized neutron star, a magnetar, with an equivalent dipole field of nearly twenty times the quantum critical magnetic field. Our conclusions were based on two epochs of measurement of the spin, along with an age estimate of the host supernova remnant. Herein, we present a spin chronology of the pulsar using additional GINGA, ASCA, XTE, & SAX datasets spanning over a decade. Timing and spectral analysis confirms our initial results and severely limit an accretion origin for the observed flux. Over the 10 year baseline, the pulsar is found to undergo a rapid, constant spindown, while maintaining a steady flux and an invariant pulse profile. Within the measurement uncertainties, no systematic departures from a linear spin-down are found - departures as in the case of glitches or simply stochastic fluctuations in the pulse times-of-arrival (e.g. red timing noise). We suggest that this pulsar is akin to the soft gamma-ray repeaters, however, it is remarkably stable and has yet to display similar outbursts; future gamma-ray activity from this object is likely.Comment: 6 pages with 3 embedded figures, LaTex, emulateapj.sty. Submitted to the ApJ Letter

Household Social Environmental Influences on African-American Adolescents’ Smoking Habits

Because most smokers begin smoking during adolescence and because there are few studies that focus on African-American adolescent’s smoking behavior, the purpose of this study was to determine if a significant difference exists in the prevalence of smoking between African-American adolescent teens living with household members who smoke and those living with household members who do not smoke. The subjects in this study were 585 adolescents (342 females and 243 males) who received services at the Center Hill Health Center from 2001 to 2004. The data was collected from the medical records of the clients selected for this study. The data in this study was analyzed using chi square tests of independence. The first analysis revealed that a significant difference existed between the smoking status of the household members of adolescents who were smokers compared to those who where non- smokers (? 2 = 14.58, df = 1, p < .05.)

Reasons Youth of Color Give for Not Accessing Primary Health Care: A Survey of Patients at a Teen Clinic

Survey research was conducted on patients seen at Grady Teen Clinic in Atlanta, Georgia to investigate the reasons this population, predominantly composed of youth of color, gives for not accessing primary health care. Subjects for the study were males and females aged 13-19 who attended the clinic as patients during the year 2004. Data was collected from forms contained in the teens’ medical records. A majority (53%) of the subjects (n=5210) answered that the cost of medical care was their main reason for not accessing primary health care (53%), followed by lack of health insurance (44%), fear of parents learning about their visit (42%) and not knowing where to access health care (29.4%). Responses regarding cultural and language barriers (7.3%), difficulty getting or keeping appointments (9.1%) and waiting time (3.5%) were the least frequent answers. A chi square analysis revealed males and females differed significantly with respect to reasons for not accessing health care

Anomalous Chiral Behavior in Quenched Lattice QCD

A study of the chiral behavior of pseudoscalar masses and decay constants is carried out in quenched lattice QCD with Wilson fermions. Using the modified quenched approximation (MQA) to cure the exceptional configuration problem, accurate results are obtained for pion masses as low as $\approx$ 200 MeV. The anomalous chiral log effect associated with quenched $\eta'$ loops is studied in both the relation between $m_{\pi}^2$ vs. $m_q$ and in the light-mass behavior of the pseudoscalar and axial vector matrix elements. The size of these effects agrees quantitatively with a direct measurement of the $\eta'$ hairpin graph, as well as with a measurement of the topological susceptibility, thus providing several independent and quantitatively consistent determinations of the quenched chiral log parameter $\delta$. For $\beta=5.7$ with clover-improved fermions $(C_{sw} =1.57)$ all results are consistent with $\delta=0.065\pm 0.013$ .Comment: 51 pages, 20 figures, Late