1,245 research outputs found

    Conformations And Relative Stabilities Of The Cis And Trans Isomers In A Series Of Isolated N-phenylamides

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    The gas-phase conformations of a series of isolated N-phenylamides have been determined from vibrationally resolved electronic spectra obtained by resonant two-photon ionization in a supersonic jet expansion. Both the cis and trans isomers of formanilide were identified, with the cis isomer in 6.5% abundance. The spectral features displayed by this isomer are consistent with a nonplanar geometry which undergoes a large change in the phenyl torsional angle following electronic excitation. The more abundant trans isomer of formanilide adopts a planar structure and is stabilized by 2.5 kcal/mol with respect to the cis isomer. In the excited electronic state the relative stabilities of the two isomers are reversed. Acetanilide, in contrast, is found exclusively as the trans isomer, also having a planar structure. N-Methyl substitution causes a reversal of the relative isomer stabilities found in formanilide and leads to an isomer distribution consisting of approximately 90% E and 10% Z in N-methylformanilide. These experimental observations are compared to previous condensed phase structural determinations as well as to the relative energies and structures predicted from ab initio Hartree-Fock geometry optimizations

    Qualitative investigation of patients' experience of a glaucoma virtual clinic in a specialist ophthalmic hospital in London, UK

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    OBJECTIVES: To explore how patients felt about delivery of care in a novel technician-delivered virtual clinic compared with delivery of care in a doctor-delivered model. DESIGN: A qualitative investigation using one-to-one interviews before and after patients' appointments at either the standard outpatient glaucoma clinic or the new technician-delivered virtual glaucoma clinic (Glaucoma Screening and Stable Monitoring Service, GSMS). SETTING: A glaucoma clinic based in a tertiary ophthalmic specialist hospital in London. PARTICIPANTS: 43 patients (38 Caucasian, 5 African/Afro-Caribbean) were interviewed prior to their glaucoma appointment; 38 patients were interviewed between 4 and 6 weeks after their appointment. Consecutive patients were identified from patient reception lists and telephoned prior to their appointment inviting them to participate. RESULTS: Trust in the patient-provider relationship emerged as a key theme in patients' acceptance of not being seen in a traditional doctor-delivered service. Patients who were well informed regarding their glaucoma status and low risk of progression to sight loss were more accepting of the GSMS. Patients valued the reassurance received through effective communication with their healthcare practitioner at the time of their appointment. CONCLUSIONS: This study suggests that patients are accepting of moving to a model of service delivery whereby the doctor is removed from the consultation as long as they are informed about the status of their condition and reassured by the interaction with staff they meet. This study highlights the importance of patient engagement when introducing new models of service delivery

    Concept definition study for recovery of tumbling satellites. Volume 1: Executive summary, study results

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    The first assessment is made of the design requirements and conceptual definition of a front end kit to be transported on the currently defined Orbital Maneuvering Vehicle (OMV) and the Space Transportation System Shuttle Orbiter, to conduct remote, teleoperated recovery of disabled and noncontrollable, tumbling satellites. Previous studies did not quantify the dynamic characteristics of a tumbling satellite, nor did they appear to address the full spectrum of Tumbling Satellite Recovery systems requirements. Both of these aspects are investigated with useful results

    Concept definition study for recovery of tumbling satellites. Volume 2: Supporting research and technology report

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    A number of areas of research and laboratory experiments were identified which could lead to development of a cost efficient remote, disable satellite recovery system. Estimates were planned of disabled satellite motion. A concept is defined as a Tumbling Satellite Recovery kit which includes a modular system, composed of a number of subsystem mechanisms that can be readily integrated into varying combinations. This would enable the user to quickly configure a tailored remote, disabled satellite recovery kit to meet a broad spectrum of potential scenarios. The capability was determined of U.S. Earth based satellite tracking facilities to adequately determine the orientation and motion rates of disabled satellites

    Quantum States of Light Produced by a High-Gain Optical Parametric Amplifier for Use in Quantum Lithography

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    We present a theoretical analysis of the properties of an unseeded optical parametic amplifier (OPA) used as the source of entangled photons for applications in quantum lithography. We first study the dependence of the excitation rate of a two-photon absorber on the intensity of the light leaving the OPA. We find that the rate depends linearly on intensity only for output beams so weak that they contain fewer than one photon per mode. We also study the use of an N-photon absorber for arbitrary N as the recording medium to be used with such a light source. We find that the contrast of the interference pattern and the sharpness of the fringe maxima tend to increase with increasing values of N, but that the density of fringes and thus the limiting resolution does not increase with N. We conclude that the output of an unseeded OPA exciting an N-photon absorber provides an attractive system in which to perform quantum lithography

    Association between social isolation and smoking in Japan and England

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    BACKGROUND: Existing evidence suggest that those who are socially isolated are at risk for taking up or continuing smoking. This study investigated country-based differences in social isolation and smoking status. METHODS: We performed a repeated cross-sectional study using two waves of data from two ongoing aging studies: the English Longitudinal Study of Ageing and the Japan Gerontological Evaluation Study. Participants from both studies aged ≥65 years old were included. We applied a multilevel Poisson regression model to examine the association between social isolation and smoking status and adjusted for individual sociodemographic characteristics. We used the social isolation index which comprises the following domains: marital status; frequency of contact with friends, family, and children; and participation in social activities. Interaction terms between each country and social isolation were also entered into the mode. RESULTS: After exclusion of never smokers, we analyzed 75,905 participants (7,092 for ELSA and 68,813 for JAGES, respectively). Taking ex-smokers as the reference, social isolation was significantly associated with current smoking; the prevalence ratios (PRs; 95% credible intervals [CrIs]) were 1.06 (1.05-1.08) for men and 1.08 (1.04-1.11) for women. Taking Japan as a reference, the interaction term between country and social isolation was significant for both sexes, with increased PRs (95% CrIs) of 1.32 (1.14-1.50) for men and 1.30 (1.11-1.49) for women in England. CONCLUSIONS: Older people who were less socially isolated were more likely to quit smoking in England than in Japan, possibly explained by the strict tobacco control policies in England

    Association between social isolation and depression onset among older adults: a cross-national longitudinal study in England and Japan

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    OBJECTIVE: Social isolation is a risk factor for depression in older age. However, little is known regarding whether its impact varies depending on country-specific cultural contexts regarding social relationships. The present study examined the association of social isolation with depression onset among older adults in England, which has taken advanced measures against social isolation, and Japan, a super-aged society with a rapidly increasing number of socially isolated people. DESIGN: Prospective longitudinal study. SETTING: We used data from two ongoing studies: the English Longitudinal Study of Ageing (ELSA) and the Japan Gerontological Evaluation Study (JAGES). PARTICIPANTS: Older adults aged ≥65 years without depression at baseline were followed up regarding depression onset for 2 years (2010/2011–2012/2013) for the ELSA and 2.5 years (2010/2011–2013) for the JAGES. PRIMARY OUTCOME MEASURE: Depression was assessed with eight items from the Centre for Epidemiologic Studies Depression Scale for the ELSA and Geriatric Depression Scale for the JAGES. Multivariable logistic regression analysis was performed to evaluate social isolation using multiple parameters (marital status; interaction with children, relatives and friends; and social participation). RESULTS: The data of 3331 respondents from the ELSA and 33 127 from the JAGES were analysed. Multivariable logistic regression analysis demonstrated that social isolation was significantly associated with depression onset in both countries. In the ELSA, poor interaction with children was marginally associated with depression onset, while in the JAGES, poor interaction with children and no social participation significantly affected depression onset. CONCLUSIONS: Despite variations in cultural background, social isolation was associated with depression onset in both England and Japan. Addressing social isolation to safeguard older adults’ mental health must be globally prioritised

    The beta-decay of 22Al

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    In an experiment performed at the LISE3 facility of GANIL, we studied the decay of 22Al produced by the fragmentation of a 36Ar primary beam. A beta-decay half-life of 91.1 +- 0.5 ms was measured. The beta-delayed one- and two-proton emission as well as beta-alpha and beta-delayed gamma decays were measured and allowed us to establish a partial decay scheme for this nucleus. New levels were determined in the daughter nucleus 22Mg. The comparison with model calculations strongly favours a spin-parity of 4+ for the ground state of 22Al
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