Closed-Flux Solutions to the Constraints for Plane Gravity Waves

The metric for plane gravitational waves is quantized within the Hamiltonian framework, using a Dirac constraint quantization and the self-dual field variables proposed by Ashtekar. The z axis (direction of travel of the waves) is taken to be the entire real line rather than the torus (manifold coordinatized by (z,t) is RxR rather than $S_1$ x R). Solutions to the constraints proposed in a previous paper involve open-ended flux lines running along the entire z axis, rather than closed loops of flux; consequently, these solutions are annihilated by the Gauss constraint at interior points of the z axis, but not at the two boundary points. The solutions studied in the present paper are based on closed flux loops and satisfy the Gauss constraint for all z.Comment: 18 pages; LaTe

Neoepicrius, Gen. N., from Western North America (Acari : Mesostigmata : Epicriidae)

Summary: Neoepicrius, a paedomorphic genus of Epicriidae, is described as new with Neoepicrius krantzi sp. n. fromOregon designated as type species. Also described as new are Neoepicrius californicus (California), Neoepicrius intermedius (British Columbia), Neoepicrius titanus (British Columbia), and Neoepicrius orphanus (British Columbia). Neoepicrius sp. (California), known from one male, is described but not named. A key to species, based on adult females, is provided.Résumé: Neoepicrius, nouveau genre paedomorphe d’Epicriidae, est défini et Neoepicrius krantzi sp. n. d’Oregon désigné espèce type. Neoepicrius californicus (Californie), Neoepicrius intermedius (Colombie britannique) Neoepicrius titanus (Colombie britannique), et Neoepicrius orphanus (Colombie britannique) sont aussi décrits. Neoepicrius sp. (Californie) connu par le mâle, est décrit mais non nommé. Une clé de reconnaissance des espèces basée sur les femelles adultes est fournie

Isotope effects and possible pairing mechanism in optimally doped cuprate superconductors

We have studied the oxygen-isotope effects on T_{c} and in-plane penetration depth \lambda_{ab}(0) in an optimally doped 3-layer cuprate Bi_{1.6}Pb_{0.4}Sr_{2}Ca_{2}Cu_{3}O_{10+y} (T_{c} \sim 107 K). We find a small oxygen-isotope effect on T_{c} (\alpha_{O} = 0.019), and a substantial effect on \lambda_{ab} (0) (\Delta \lambda_{ab} (0)/\lambda_{ab} (0) = 2.5\pm0.5%). The present results along with the previously observed isotope effects in single-layer and double-layer cuprates indicate that the isotope exponent \alpha_{O} in optimally doped cuprates is small while the isotope effect on the in-plane effective supercarrier mass is substantial and nearly independent of the number of the CuO_{2} layers. A plausible pairing mechanism is proposed to explain the isotope effects, high-T_{c} superconductivity and tunneling spectra in a consistent way.Comment: 5 pages, 4 figure

Productivity premia and firm heterogeneity in Eastern Africa

Productivity development is a key issue for export-driven growth and development. We use East African Community (EAC) firm-level data. Instead of focusing on single EAC partners, using the World Bank Enterprise Surveys, investigate firm-level productivity difference for seven countries that are part of the COMESA-EAC-SADC tripartite free trade area (TFTA). Using export and ownership dimensions, we identify four types of firms: National Domestic, National Exporters, Foreign Domestic and Foreign Exporters. We find a clear export productivity premium for national manufacturing firms and service sectors, but not for foreign owned firms. We also find clear foreign-ownership productivity premium for both domestic and exporting firms in manufacturing sectors but less clear in services sectors. The gap between national export premium and foreign-ownership premium is stronger in manufacturing firms as opposed to service sectors. Moreover, we find clear and strong productivity premia in size, training programmes and level of development in the manufacturing firms. In the services sector, these premia are always smaller and only significant for medium-sized firms. There is no difference in experience premium between sectors in terms of both significance and magnitude of the estimated coefficients

Effects of daily porcine somatotropin administration on tile performance and carcass characteristics of finishing swine

One hundred forty-four pigs (72 barrows and 72 gilts) were utilized in six treatments with six pens each to evaluate four levels of daily porcine somatotropin (pST) injections (0, 1, 3, or 5 mg/d) in combination with diets containing 13 or 16% crude protein (CP). One randomly selected pig from each pen was slaughtered when it reached a weight between 230 and 240 lb. Daily feed intake (ADFI), tenth rib backfat, and estimated percentage of lean pork were reduced in pigs fed the 13% CP diet and injected with 3 mg/d pST compared to pigs fed the same diet and injected daily with a placebo. Feed intake was reduced in pigs fed the 16% CP diet and injected daily with 3 and 5 mg/d pST. Improvement in feed conversion (F/G), tenth rib backfat, and estimated percentage lean pork occurred when pigs fed the 16% CP diet were injected with 1 mg/d, with greater improvements occurring at the 3 and 5 mg/d levels of pST. The improvement in F/G and the greater magnitude of response observed in pigs fed 16% CP diets compared to the response of pigs fed the 13% CP diet indicate that both the performance and carcass characteristics of pigs injected with pST are dependent on the dietary CP content

An inclusive search for free quarks at PEP

Abstract We report the results of a search for fractionally charged particles in e + e − reactions at a center of mass energy of 29 GeV. We find no evidence for such particles and present upper limitts on R q = σ q q X/σ μμ for change 1 3 e and 2 3 e which range from 1 to 8 × 10 −2 for mass up to 12 GeV/ c 2

Search for fractionally charged particles in cosmic rays at large zenith angles

We have performed a single-particle search for fractional charge in cosmic rays having residual ranges at sea level >250 g/cm/sup 2/ concrete and zenith angles between 45/sup 0/ and 90/sup 0/. The detector is a hodoscope of 24 layers of plastic scintillator, eight layers of multiwire proportional chambers, and two layers of lucite Cherenkov counters. The acceptance of the instrument is 4.0 x 10/sup 3/ cm/sup 2/sr. An analysis of 3.5 x 10/sup 6/ triggers during a running time of 8 x 10/sup 5/ sec yields no particles with charge Q = (1/3) or Q = (2/3) and velocities greater than roughly-equal0.1c. We deduce an upper limit on the flux of fractionally charged particles of 8.5 x 10/sup -10/ (cm/sup 2/sr sec)/sup -1/ for relativistic Q = (1/3) and 7.6 x 10/sup -10/ (cm/sup 2/sr sec)/sup -1/ for Q = (2/3)

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

A multilaboratory comparison of calibration accuracy and the performance of external references in analytical ultracentrifugation.

Analytical ultracentrifugation (AUC) is a first principles based method to determine absolute sedimentation coefficients and buoyant molar masses of macromolecules and their complexes, reporting on their size and shape in free solution. The purpose of this multi-laboratory study was to establish the precision and accuracy of basic data dimensions in AUC and validate previously proposed calibration techniques. Three kits of AUC cell assemblies containing radial and temperature calibration tools and a bovine serum albumin (BSA) reference sample were shared among 67 laboratories, generating 129 comprehensive data sets. These allowed for an assessment of many parameters of instrument performance, including accuracy of the reported scan time after the start of centrifugation, the accuracy of the temperature calibration, and the accuracy of the radial magnification. The range of sedimentation coefficients obtained for BSA monomer in different instruments and using different optical systems was from 3.655 S to 4.949 S, with a mean and standard deviation of (4.304 ± 0.188) S (4.4%). After the combined application of correction factors derived from the external calibration references for elapsed time, scan velocity, temperature, and radial magnification, the range of s-values was reduced 7-fold with a mean of 4.325 S and a 6-fold reduced standard deviation of ± 0.030 S (0.7%). In addition, the large data set provided an opportunity to determine the instrument-to-instrument variation of the absolute radial positions reported in the scan files, the precision of photometric or refractometric signal magnitudes, and the precision of the calculated apparent molar mass of BSA monomer and the fraction of BSA dimers. These results highlight the necessity and effectiveness of independent calibration of basic AUC data dimensions for reliable quantitative studies