Detection of crop mark contrast for archaeological surveys

There are no author-identified significant results in this report

Real space first-principles derived semiempirical pseudopotentials applied to tunneling magnetoresistance

In this letter we present a real space density functional theory (DFT) localized basis set semi-empirical pseudopotential (SEP) approach. The method is applied to iron and magnesium oxide, where bulk SEP and local spin density approximation (LSDA) band structure calculations are shown to agree within approximately 0.1 eV. Subsequently we investigate the qualitative transferability of bulk derived SEPs to Fe/MgO/Fe tunnel junctions. We find that the SEP method is particularly well suited to address the tight binding transferability problem because the transferability error at the interface can be characterized not only in orbital space (via the interface local density of states) but also in real space (via the system potential). To achieve a quantitative parameterization, we introduce the notion of ghost semi-empirical pseudopotentials extracted from the first-principles calculated Fe/MgO bonding interface. Such interface corrections are shown to be particularly necessary for barrier widths in the range of 1 nm, where interface states on opposite sides of the barrier couple effectively and play a important role in the transmission characteristics. In general the results underscore the need for separate tight binding interface and bulk parameter sets when modeling conduction through thin heterojunctions on the nanoscale.Comment: Submitted to Journal of Applied Physic

Introductory Remarks and Keynote Speaker Address

In other industries, experts may see up to four issues a day, but for us, the Conference is an opportunity to share ideas with colleagues, regulators, and others who shape national regulatory policy. For that reason, we have built into our schedule a formal gathering to discuss these issues, and we trust that all of you will take advantage of this meaningful opportunity. Of course, we have to thank Tony Gambardella and his committee for putting on such a wonderful program today, and I am pleasantly surprised that this conference is a joint- venture opportunity with the State Corporation Commission ( Commission ) and The College of William and Mary. Maintaining a special relationship with the Commission is very important to us, to our bar group, and to practitioners who appear before the Commission. This Conference allows members of this Virginia State Bar Administrative Law Section ( Section ) and others, like veteran practitioners to better represent our clients before the Commission. This Conference will help the Commission to make decisions that will ultimately result in appropriate regulations to benefit Virginia consumers. We appreciate our relationship with the Virginia Commission, and its importance to the Conference

Molecular Dynamics in Hydrogen‐bonded Interactions: A Preliminary Experimentally Determined Harmonic Stretching Force Field for HCN‐‐‐HF

Observation of the 2ν1 overtone band in the hydrogen‐bonded complex HCN‐‐‐HF permits evaluation of the anharmonicity constant X 1 1=−116.9(1) cm− 1 and determination of the anharmonicity corrected fundamental frequency ω1. This information, and available data from previous rovibrational analyses in the common and perdeuterated isotopic species of HCN‐‐‐HF, offer an opportunity for calculation of an approximate stretching harmonic force field. With the assumptions f 1 2=f 2 4=0.0, the remaining force constants (in mdyn/Å) are evaluated as: f 1 1=8.600(20), f 2 2=6.228(9), f 3 3=19.115(40), f 4 4=0.2413(39), f 1 3=0.000(13), f 1 4=0.0343(2), f 2 3=−0.211(6), f 3 4=0.000(2). These compare to f 1 1=9.658(2) in the HF monomer and f 1 1=6.244(3) and f 3 3=18.707(16) in the HCN monomer. These results provide the information necessary to quantitatively assess the applicability of the Cummings and Wood approximation in this hydrogen‐bonded complex and also give an estimate of D e j , the equilibrium distortion constant in the harmonic limit. Comparisons of these experimentally determined parameters with the predictions of a b i n i t i o molecular orbital calculations at several levels of approximation are presented

Reply to Comment "Invalidity of classes of approximate Hall effect calculations."

We reply to the criticism raised by Ao in his Comment (cond-mat/9801180). Being unable to properly treat the Hall conductivity in a mixed state of superconductors, Ao is looking for possible mistakes in microscopic and phenomenological calculations, as well as in the corresponding experiments. The errors in his treatment of the problem (cond-mat/9704247) are analized. We indicate where the approach advocated by him fails to properly account for the interaction with impurities and other sources of relaxation.Comment: reply to Comment by Ao (cond-mat/9801180) on our paper in PRL, 79, 1377 (1997), revtex file, 1 page, no figure

Modifications of Gait as Predictors of Natural Osteoarthritis Progression in STR/Ort Mice

OBJECTIVE: Osteoarthritis (OA) is a common chronic disease for which disease-modifying therapies are not currently available. Studies to seek new targets for slowing the progress of OA rely on mouse models, but these do not allow for longitudinal monitoring of disease development. This study was undertaken to determine whether gait can be used to measure disease severity in the STR/Ort mouse model of spontaneous OA and whether gait changes are related to OA joint pain. METHODS: Gait was monitored using a treadmill-based video system. Correlations between OA severity and gait at 3 treadmill speeds were assessed in STR/Ort mice. Gait and pain behaviors of STR/Ort mice and control CBA mice were analyzed longitudinally, with monthly assessments. RESULTS: The best speed to identify paw area changes associated with OA severity in STR/Ort mice was found to be 17 cm · seconds(−1). Paw area was modified with age in CBA and STR/Ort mice, but this began earlier in STR/Ort mice and correlated with the onset of OA at 20 weeks of age. In addition, task noncompliance appeared at 20 weeks. Surprisingly, STR/Ort mice did not show any signs of pain with OA development, even when treated with the opioid antagonist naloxone, but did exhibit normal pain behaviors in response to complete Freund's adjuvant–induced arthritis. CONCLUSION: The present results identify an animal model in which OA severity and OA pain can be studied in isolation from one another. The findings suggest that paw area and treadmill noncompliance may be useful tools to longitudinally monitor nonpainful OA development in STR/Ort mice. This will help in providing a noninvasive means of assessing new therapies to slow the progression of OA

Vortex Mass in BCS systems: Kopnin and Baym-Chandler contributions

The Kopnin mass and the Baym-Chandler mass of the vortex have the same origin. Both represent the mass of the normal component trapped by the vortex. The Kopnin mass of the vortex is formed by quasiparticles localized in the vicinity of the vortex. In the superclean limit it is calculated as linear response exactly in the same way as the density of the normal component is calculated in homogeneous superfluid. The Baym-Chandler mass is the hydrodynamical (associated) mass trapped by vortex. It is analogous to the normal component formed by inhomogeneities, such as pores and impurities. Both contributions are calculated for the generic model of the continuous vortex core.Comment: revtex file, 3 pages, 1 figure. Initially appeared as Comment to the paper by E.B. Sonin et al "Vortex motion in charged and neutral superfluids: A hydrodynamic approach" (Phys. Rev. B 57, 575 (1998)). The calculation of the backflow mass is adde

Comment on "Transverse Force on a Quantized Vortex in a Superfluid"

The result of Thouless, Ao and Niu (TAN), that the mutual friction parameter $d_\perp =0$, contradicts to the experiments made in rotating 3He-B by Manchester group. The Manchester group observed that $d_\perp <0$ at low temperature and approaches 1 at high temperature. The reason of the contradiction is that TAN did not take into account the Iordanskii force on the vortex and the spectral flow force, which comes from the anomaly related to the low-energy bound states of fermions in cores of quantized vortices. The Iordanskii force is responsible for the negative $d_\perp <0$ at low temperature, while due to the spectral flow $d_\perp$ approaches 1 at high temperature. Relation of the spectral flow anomaly with the paradoxes of the linear and angular momenta in gapless superfluids is discussed.Comment: revtex, 2 pages, submitted to Physical Review Letters as "Comment" to the paper D.J. Thouless, P. Ao and Q. Niu, Phys. Rev. Lett. 76, 3758 (1996