Interface Ferromagnetism in a SrMnO3/LaMnO3 Superlattice

Resonant soft x-ray absorption measurements at the O K edge on a SrMnO3/LaMnO3 superlattice show a shoulder at the energy of doped holes, which corresponds to the main peak of resonant scattering from the modulation in the doped hole density. Scattering line shape at the Mn L3,2 edges has a strong variation below the ferromagnetic transition temperature. This variation has a period equal to half the superlattice superperiod and follows the development of the ferromagnetic moment, pointing to a ferromagnetic phase developing at the interfaces. It occurs at the resonant energies for Mn3+ and Mn4+ valences. A model for these observations is presented, which includes a double-exchange two-site orbital and the variation with temperature of the hopping frequency tij between the two sites.Comment: 8.1 pages, 6 figure

Effects of CP Violation from Neutral Heavy Fermions on Neutrino Oscillations, and the LSND/MiniBooNE Anomalies

Neutrinos may mix with ultralight fermions, which gives flavor oscillations, and with heavier fermions, which yields short distance flavor change. I consider the case where both effects are present. I show that in the limit where a single oscillation length is experimentally accessible, the effects of heavier fermions on neutrino oscillations can generically be accounted for by a simple formula containing four parameters, including observable CP violation. I consider the anomalous LSND and MiniBooNE results, and show that these can be fit in a model with CP violation and two additional sterile neutrinos, one in the mass range between 0.1 and 20 eV, and the other with mass between 33 eV and 40 GeV. I also show that this model can avoid conflict with constraints from existing null short baseline experimental results.Comment: 12 pages, 3 figure

Radiation counting technique allows density measurement of metals in high-pressure/ high-temperature environment

Radioactive tracers induced by neutron irradiation provide a gamma ray flux proportional to the density of a metal, allowing density measurement of these metals in extreme high-temperature and high-pressure environments. This concept is applicable to most metals, as well as other substances

The Impact of Failing to Identify Suspect Effort in Patients Undergoing Adult Attention-Deficit/Hyperactivity Disorder (ADHD) Assessment

This retrospective study examines how many adult patients would plausibly receive a diagnosis of attention-deficit/hyperactivity disorder (ADHD) if performance and symptom validity measures were not administered during neuropsychological evaluations. Five hundred fifty-four patients were extracted from an archival clinical dataset. A total of 102 were diagnosed with ADHD based on cognitive testing, behavior rating scales, effort testing, and clinical interview; 115 were identified as putting forth suspect effort in accordance with the Slick, Sherman, and Iverson (1999) criteria. From a clinical decision-making perspective, suspect effort and ADHD groups were nearly indistinguishable on ADHD behavior, executive function, and functional impairment rating scales, as well as on cognitive testing and key clinical interview questions. These results suggest that a significant percentage of those making a suspect effort will be diagnosed with ADHD using the most commonly employed assessment methods: an interview alone (71%); an interview and ADHD behavior rating scales combined (65%); and an interview, behavior rating scales, and most continuous performance tests combined (57%). This research makes clear that it is essential to evaluate task engagement and possible symptom amplification during clinical evaluations

Hearing Conservation Program For Marching Band Members: A Risk For Noise-Induced Hearing Loss?

Purpose: To examine the risk for noise-induced hearing loss (NIHL) in university marching band members and to provide an overview of a hearing conservation program for a marching band. Method: Sound levels during band rehearsals were recorded and audiometric hearing thresholds and transient otoacoustic emission were measured over a 3-year period. Musician's earplugs and information about hearing loss were provided to the students. The hearing thresholds of other college students were tested as a partial control. Results: There were no significant differences in hearing thresholds between the two groups. During initial testing, more marching band members showed apparent high-frequency notches than control students. Follow-up hearing tests in a subsequent year for the marching band members showed that almost all notches disappeared. Persistent standard threshold shift (STS) across tests was not observed in the band members. Conclusion: Band members showed no evidence of STS or persistent notched audiograms. Because accepted procedures for measuring hearing showed a lack of precision in reliably detecting early NIHL in marching band members, it is recommended that signs of NIHL be sought in repeated measurements compared to baseline audiograms rather than in a single measure (a single notch). A hearing conservation program for this population is still recommended because of lengthy rehearsal times with high sound-level exposure during rehearsals.Communication Sciences and Disorder

Does Wheat Cultivar Choice Affect Crop Quality and Soil Microbial Communities in Cropping Systems?

Wheat (Triticum aestivum L.) cultivars may have differential effects on soil microbial communities and the breadmaking quality of harvested grain. We compared six Canadian spring wheat cultivars under organic and conventional management systems for yield, breadmaking quality and soil phospholipid fatty acid analysis (PLFA) profile. Yields were lower, but protein levels were higher in the organic system. Cultivars differed for quality traits, but all cultivars had acceptable levels for processing. There were small differences in PLFA profiles for cultivars in the conventional system, but none in the organic system. More significant correlations between grain quality and PLFA measures were present in the organic system. Protein levels and breadmaking quality at least equal to conventional systems can be achieved in organic systems. Wheat cultivars differed for grain quality in both organic and conventional systems, and culivars altered the soil microbial profile in conventional systems. Microbes may play a greater role in determining crop quality in organic systems than in conventional systems

Free Energies of Isolated 5- and 7-fold Disclinations in Hexatic Membranes

We examine the shapes and energies of 5- and 7-fold disclinations in low-temperature hexatic membranes. These defects buckle at different values of the ratio of the bending rigidity, $\kappa$, to the hexatic stiffness constant, $K_A$, suggesting {\em two} distinct Kosterlitz-Thouless defect proliferation temperatures. Seven-fold disclinations are studied in detail numerically for arbitrary $\kappa/K_A$. We argue that thermal fluctuations always drive $\kappa/K_A$ into an ``unbuckled'' regime at long wavelengths, so that disclinations should, in fact, proliferate at the {\em same} critical temperature. We show analytically that both types of defects have power law shapes with continuously variable exponents in the ``unbuckled'' regime. Thermal fluctuations then lock in specific power laws at long wavelengths, which we calculate for 5- and 7-fold defects at low temperatures.Comment: LaTeX format. 17 pages. To appear in Phys. Rev.

Spin-charge-lattice coupling near the metal-insulator transition in Ca3Ru2O7

We report x-ray scattering studies of the c-axis lattice parameter in Ca3Ru2O7 as a function of temperature and magnetic field. These structural studies complement published transport and magnetization data, and therefore elucidate the spin-charge-lattice coupling near the metal-insulator transition. Strong anisotropy of the structural change for field applied along orthogonal in-plane directions is observed. Competition between a spin-polarized phase that does not couple to the lattice, and an antiferromagnetic metallic phase, which does, gives rise to rich behavior for B $\parallel$ b.Comment: 6 pages, 4 figures, to appear in Phys. Rev.