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Notes: Six internal rotation/vibration bands of ArH2O are observed in a slit supersonic expansion via direct absorption of a tunable diode laser in the v2 bend region of H2O. The spectra obtained for the ortho H2O manifold are well represented by a pseudodiatomic model with nearly free internal rotation of the H2O subunit. By way of contrast, the para bands show significant mixing between the internal rotor and stretch states, indicative of strong angular-radial coupling in the intermolecular potential. The spectra for the para Ar–H2O species can be deperturbed based on a three state Coriolis plus angular-radial coupling model which includes microwave, far-ir and near-ir data. The results indicate a redshift of (approximate)0.58 cm−1 upon bend excitation of the H2O subunit, and in general rather modest changes in the excited state intermolecular potential from the ground state potential. No indication of predissociation broadening is found, and the instrument-limited linewidths place a lower limit on the vibrational lifetime in the excited state of τ≥7.2(6) ns. © 1997 American Institute of Physics.

Notes: Absolute state-to-state cross sections are reported for rotationally inelastic scattering in crossed jets of HF with He, Ne, and Ar at mean center-of-mass collision energies of 480, 390, and 350 cm−1, respectively. HF seeded in Ar diluent gas is cooled into the J=0 ground rotational state in a pulsed supersonic expansion, followed by single collision rotational excitation with rare gas atoms from a second pulsed supersonic jet. The column-integrated densities of HF in both the initial and final scattering states are probed in the jet intersection region via direct absorption of light from a narrow bandwidth (0.0001 cm−1), continuously tunable, color center laser. Total inelastic cross sections for collisional loss out of J=0 and collisional excitation into J〉0 states are determined in absolute units from the dependence of infrared absorption signals on collider gas concentration. Full close coupling scattering calculations are performed on several ab initio and empirical potential energy surfaces for each of the three HF+rare gas systems. Agreement for He+HF and Ar+HF integral cross sections is remarkably good, but significant discrepancies are noted for the less accurately determined Ne+HF surface. Photoelastic polarization modulation of the IR laser is used to probe for rotational alignment in the scattered HF flux; the measurements set an upper polarizance limit for collisionally populated J=1 HF molecules [probed on P(1)] of |P|〈2%. High resolution IR laser Dopplerimetry reveals velocity structure in the collisionally excited J=1 Doppler profiles, which is in excellent qualitative agreement with theoretical predictions of rainbow features in the J=1←0 state-to-state differential cross section. © 1997 American Institute of Physics.

Notes: Uncontrolled weeds reduced tobacco yields by 26% over a 4-year period, caused substantial changes in the grade distribution, significantly reduced the price index and affected the chemical composition of flue-cured tobacco (cultivar Hicks). Treatments with diphenamid, pebulate, or benfluralin-pubulate visibly injured transplanted tobacco. After diphenamid treatment, tobacco generally did not differ from the cultivated controls in yield or gross dollar returns. In contrast, the mixture of benfluralin-pebulate increased dollar returns per hectare. The most striking differences followed pebulate applied alone which increased tobacco yields, significantly increased dollar returns, and elevated the levels of total nitrogen and alkaloids in tobacco leaves. All herbicide treatments tended to improve the grading quality of Hicks tobacco. Effets du disherbage sur le rendement et la qualité du tabac séchéè I'air chaud Les mauvaises herbes non détruites ont provoqué, sur une période de 4 ans une réduction de 25% des récoltes de tabac, provoquant des changeinents importants dans la répartition des catégories, une réduction significative de l'index des prix et une modification de la composition chimique du tabac séchéè I'air chaud (cultivar ‘Hicks’). Des traitements avec le diphénamide, le pébulate, ou le mélange benfluraline-prébulate ont provoquée des dommages visibles sur des tabacs repiqués. Le tabac, après un traitement au diphénamide ne donnait généralement pas des rendements différents des témoins, ni en production, ni en rentabilité brute. Au con-traire, le mélange benfluraline-pébulate augmenta le revenu brut è l'hectare. Les différences les plus frappantes furent obtenues après application du pébulate seul, lequel augmenta la production ainsi que le revenu brut (significativement) et releva les niveaux d'azote total et d'alcaloïdes dans les feuilles de tabac. Tous les traitements herbicides eurent tendance è augmenter la qualité du tabac ‘Hicks’. Der Einfluss der Unkrautbekämpfung auf Ertrag und Qualität von röhrengetrocknetem Tabak Über eine Versuchszeit von 4 Jahren führte Verunkrautung zu 26% Minderertrag, verursachte wesentliche Veränderungen in den Güteklassen, verringerte deutlich den Preisindex und veränderte die chemische Zusammensetzung von röhrengetrocknetem (flue-cured) Tabak (Sorte Hicks). Behandlungen mit Diphenamid, Pebulate oder Benfluralin-Pebulate führten bei gepflanztem Tabak zu sichtbaren Schäden. Der Dollar-Rohertrag war beim mit Diphenamid behandelten Tabak und beim Tabak in Unbehandelt im allgemeinen gleich hoch. Dagegen wurde das Einkommen durch die Mischung Benfluralin-Pebulate erhöht. Der auffälligste Unterschied oirde durch alleinige Anwendung von Pebulate erzielt, was sich in höheren Tabak- und Dollarerträgen und höheren Gehalten an Stickstoff und Alkaloiden in den Tabakblättern niederschlug. Alle Herbizidbehandlungen verbesserten die Güteklasse von Hicks-Tabak.

Notes: Background An association between psychological morbidity and asthma is well recognized and an increase in negative psychosocial factors in brittle asthma has been previously reported. Stich factors, apart from affecting patient perceptions, may alter patients’ self-management of their condition.Methods We have undertaken a case-control study on 29 well characterized brittle and non-brittle asthmatics in the West Midlands Region to assess their level of psychological morbidity, using the General Health Questionnaire (GHQ) and the living with asthma questionnaire, and their responses to changes in asthma symptoms, using the Asthma Symptom Checklist and a taped interview.Results Significant differences in GHQ (mean score brittle 19.5 vs non-brittle 7.2, P = 0.0002) and living with asthma (mean score brittle 1.30 vs non-brittle 1.00, P = 0.002) reinforced the presence of psychological factors in this group of patients with severe asthma. Interviews regarding responses to hypothetical asthma attacks showed that patients with brittle asthma delayed seeking medical attention more often than those with non-brittle asthma and instead preferred to self-administer beta-agonist medication. Sixteen (55.2%) of the 29 patients with brittle asthma would have delayed 7 days before seeking medical attention in a slow onset attack compared with 6/29 (20.7%) in the non-brittle group. In a fast onset attack 14 (48.3%) patients with brittle asthma would not have summoned help, despite finding it difficult to walk to the kitchen for a drink whereas in the non-brittle group 24 out of 29 (82.8%) would have summoned help. Levels of family support tended to be lower in patients with brittle asthma (mean family APGAR 7.3 vs 8.65 P = 0.09).Conclusions Brittle asthma is associated with greater psychological morbidity and altered strategies for coping with deteriorating asthma symptoms. Attention should be paid to the presence of such factors in the management of patients with brittle asthma.

Notes: A retrospective analysis of long-term efficacy of percutaneous radiofrequency thermocoagulation of the trigeminal ganglion or root for the relief of trigeminal neuralgia was carried out in our unit. From the medical records and questionnaires, outcomes of 108 procedures performed in 81 patients from January 1986 to December 1990 were obtained with a follow-up period of 6–11 years. The initial success rate was 87% and the probability of remaining pain-free 1, 2 and 11 years after the procedure was 65, 49 and 26%, respectively. Patients with typical symptoms had a better long-term efficacy than those with atypical presentations, and patients who had not undergone a previous surgical procedure also had a better outcome. There was no mortality in this series. Common adverse effects included dysaesthesia in 20 patients, corneal numbness in 12 patients and masseter weakness in three patients.

Notes: Abstract By considering the phase delay introduced by a birefringent wave plate to each frequency component of a finite bandwidth light source we establish the polarisation state of the transmitted light. Realisable designs of achromatic, zero-order and high-order quarter wave and half wave plates are analysed for use with a variety of light sources with different bandwidths.