Measurements are presented of the polarisation of W\(^{+}\)W\(^{-}\) boson pairs produced in e\(^{+}\)e\(^{-}\) collisions, and of CP-violating WWZ and WW\(\gamma\) trilinear gauge couplings. The ...data were recorded by the OPAL experiment at LEP during 1998, where a total integrated luminosity of 183 pb\(^{-1}\) was obtained at a centre-of-mass energy of 189 GeV. The measurements are performed through a spin density matrix analysis of the W boson decay products. The fraction of W bosons produced with longitudinal polarisation was found to be \(\sigma_{\rm L}/\sigma_{\rm total} = (21.0 \pm 3.3 \pm 1.6)%\) where the first error is statistical and the second systematic. The joint W boson pair production fractions were found to be \(\sigma_{\rm TT}/\sigma_{\rm total} = (78.1 \pm 9.0 \pm 3.2)%\), \(\sigma_{\rm LL}/\sigma_{\rm total} = (20.1 \pm 7.2 \pm 1.8)%\) and \(\sigma_{\rm TL}/\sigma_{\rm total} = (1.8 \pm 14.7 \pm 3.8)%\). In the CP-violating trilinear gauge coupling sector we find \(\tilde{\kappa}_{\rm z} = -0.20^{+0.10}_{-0.07}\), \(g^{\rm z}_{4} = -0.02^{+0.32}_{-0.33}\) and \(\tilde{\lambda}_{\rm z} = -0.18^{+0.24}_{-0.16}\), where errors include both statistical and systematic uncertainties. In each case the coupling is determined with all other couplings set to their Standard Model values except those related to the measured coupling via \(SU(2)_{\rm L}\times U(1)_{\rm Y}\) symmetry. These results are consistent with Standard Model expectations.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The structure−activity relationships of two series of novel retinoids (2-pyrazinylcarboxamidobenzoates and β-ionylideneacetamidobenzoates) have been investigated by evaluating their ability to induce ...differentiation in both human promyelocytic leukemia (HL60) cells and mouse embryonal carcinoma (P19) cells. The most active compound (ED50 = 8.3 × 10-9 M) of the 2-pyrazinylcarboxamidobenzoates is 4-2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethylquinoxalyl)carboxamidobenzoic acid (9u), while the most active analogue of the β-ionylideneacetamidobenzoates is 4-3-methyl-5-(2‘,6‘,6‘-trimethyl-1‘-cyclohexen-1‘-yl)-(2E,4E)-pentadienamidobenzoic acid (10a, ED50 = 3.2 × 10-8 M). Our studies identify an absolute requirement for the carboxylic acid moiety on the aromatic ring to be para relative to the amide linkage for activity. Benzoate substitutions in the ortho position relative to the terminal carboxylate (9d,k,r) are well-tolerated; however, a methoxy substituent meta relative to the terminal carboxylate gives rise to only weakly active analogues (9x). Conformational studies (NMR, X-ray crystallography) of the 2-pyrazinylcarboxamidobenzoates indicate that the preferred conformation exhibits a trans-amide bond and an internal hydrogen bond between the quinoxaline N1 and HN amide which locks the torsional angle between C2 and CO in the s - trans conformation. N-Methylation (9y) results in loss of activity. Studies indicate that there is now a cis-amide bond present which redirects the carboxylate toward the pharmacophoric gem-dimethyl groups. The distance between the gem-dimethyl group and the terminal carboxylate appears to be too short to activate the retinoid receptor. N-Methylation in the β-ionylideneacetamidobenzoate series (10c) also results in the formation of a cis-amide bond and loss of activity.
Factors associated with occupational exposure and universal precautions (UP) compliance were assessed among employees in one urban school district. Half of the employees surveyed reported responding ...to bleeding injuries and cleaning blood or other body fluids (e.g., vomit, urine) during the previous school year. Also, 1 in 4 custodians and 1 in 10 teachers/teacher's aides had direct contact with blood or body fluids without protection. In multivariate logistic regression analyses, direct contact was most likely among secondary school employees in unpredictable situations who did not have protective equipment or comply with UP. UP compliance was greater among those who had protective equipment available and felt self-confident. Self-confidence was associated with having received training or protective equipment. Routine communications between administrators and employees, staff training, provision of protective equipment, and exposure incident monitoring are essential to effective implementation of UP policies in schools and work settings where occupational exposure could occur.
Full text
Available for:
BFBNIB, NMLJ, NUK, OILJ, PNG, SAZU, UKNU, UL, UM, UPUK, VSZLJ
The Whittier Narrows earthquake sequence (local magnitude, M$_{\text{L}}$ = 5.9), which caused over $358-million damage, indicates that assessments of earthquake hazards in the Los Angeles ...metropolitan area may be underestimated. The sequence ruptured a previously unidentified thrust fault that may be part of a large system of thrust faults that extends across the entire east-west length of the northern margin of the Los Angeles basin. Peak horizontal accelerations from the main shock, which were measured at ground level and in structures, were as high as 0.6g (where g is the acceleration of gravity at sea level) within 50 kilometers of the epicenter. The distribution of the modified Mercalli intensity VII reflects a broad north-south elongated zone of damage that is approximately centered on the main shock epicenter.
Full text
Available for:
BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
An ocular toxic reaction presenting as conjunctivitis or keratitis develops in a significant number of patients who are treated with high‐dose cytosine arabinoside (ara‐C). Although eye drops ...containing glucocorticoid reportedly decrease the incidence, they do not totally eliminate this side effect. In comparing this technique with artificial tears, both were found to be equally effective. The primary mechanism by which eye drops decrease ocular toxic reactions associated with high‐dose ara‐C is presumably due to dilution of intraocular concentrations of ara‐C.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
A search for the decay B
±→K
±K
±
π
∓ was performed using data collected by the OPAL detector at LEP. These decays are strongly suppressed in the Standard Model but could occur with a higher ...branching ratio in supersymmetric models, especially in those with R-parity violating couplings. No evidence for a signal was observed and a 90% confidence level upper limit of 1.29×10
−4 was set for the branching ratio.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
We present high-precision timing data over time spans of up to 11 years for 45 millisecond pulsars observed as part of the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) ...project, aimed at detecting and characterizing low-frequency gravitational waves. The pulsars were observed with the Arecibo Observatory and/or the Green Bank Telescope at frequencies ranging from 327 MHz to 2.3 GHz. Most pulsars were observed with approximately monthly cadence, with six high--timing-precision pulsars observed weekly, and all were observed at widely separated frequencies at each observing epoch in order to fit for time-variable dispersion delays. We describe our methods for data processing, time-of-arrival (TOA) calculation, and the implementation of a new, automated method for removing outlier TOAs. We fit a timing model for each pulsar that includes spin, astrometric, and, if necessary, binary parameters, in addition to time-variable dispersion delays and parameters that quantify pulse-profile evolution with frequency. The new timing solutions provide three new parallax measurements, two new Shapiro delay measurements, and two new measurements of large orbital-period variations. We fit models that characterize sources of noise for each pulsar. We find that 11 pulsars show significant red noise, with generally smaller spectral indices than typically measured for non-recycled pulsars, possibly suggesting a different origin. Future papers will use these data to constrain or detect the signatures of gravitational-wave signals.
PDF
