Patients with obstructive sleep apnea or narcolepsy report difficulty remaining alert and attentive. To detect impaired vigilance, we designed Steer Clear, a computer program simulating a long and ...monotonous highway drive that presents 780 obstacles in 30 min. Sixty-two patients with sleep apnea hit a higher percentage of obstacles (4.3 ± 0.6% SEM) than 12 age- and sex-matched subjects without sleep apnea (1.4 ± 0.3%; p<0.05) and 10 age- and sex-matched volunteers (1.2 ± 0.3%; p<0.05). Ten patients with untreated narcolepsy hit a higher percentage of obstacles while performing on Steer Clear (7.7 ± 3.2%) than 10 age- and sex-matched subjects without narcolepsy (1.2 ± 0.3%; p<0.05). Poor performance on Steer Clear was associated with a higher auto accident rate in the patients with sleep apnea or narcolepsy (p<0.01). Twenty-one patients who performed normally on Steer Clear had 1 accident in 5 years (0.05 accident/driver/5 yr), and in none of these accidents were they at fault as drivers. Twenty-five patients who performed poorly on Steer Clear had 5 auto accidents in 5 years (0.20 accident/driver/5 yr), and in 20% of these accidents they were at fault as drivers. Twenty-one patients who performed very poorly on Steer Clear had 8 auto accidents in 5 years (0.38 accident/driver/5 yr), and in 38% of these accidents they were at fault as drivers. These 21 patients who performed very poorly on Steer Clear (hitting >4.5% of obstacles) had a significantly higher auto accident rate than the patients who performed normally (hitting <1.8%). We conclude: (1) Patients with sleep apnea or narcolepsy performed more poorly on a test of vigilance, Steer Clear, than did control subjects; (2) Impaired vigilance as measured by Steer Clear is associated with a high automobile accident rate in patients with either sleep apnea or narcolepsy.
A high-resolution recoil-ion momentum spectrometer based on a precooled localized supersonic jet target (COLTRIMS) has been combined with a novel low-energy electron analyzer with 4π solid angle for ...electrons with energies
E
e ≤ 30 eV including
E
e = 0 eV. Thus, three recoil-ion momentum components, the recoil-ion charge state and three momentum components of one electron emitted in any collision-induced ionization reaction are measured simultaneously with a coincidence efficiency of 28%. In order to accept large recoil-ion longitudinal momenta (along the beam) of
p
R‖
≤ 160 a.u. and simultaneously guarantee a superior resolution in this direction (Δ
P
R‖
≤ ± 0.08 a.u.), recoil ions are extracted in the longitudinal direction different from all former concepts.
Test measurements, details on the present design and results of a kinematically complete experiment for single ionization are presented and possible further improvements are discussed. The future potential of such spectrometers for the investigation of collision-induced atomic many-particle reactions, the “Coulomb-explosion” of molecules and the spectroscopy of electronic states in heavy few-electron systems is illustrated. Similar techniques might be used to measure angular correlations and even the neutrino mass in β-decay experiments.
The reactions γp→ηp and γp→η^{'}p are measured from their thresholds up to the center-of-mass energy W=1.96 GeV with the tagged-photon facilities at the Mainz Microtron, MAMI. Differential cross ...sections are obtained with unprecedented statistical accuracy, providing fine energy binning and full production-angle coverage. A strong cusp is observed in the total cross section for η photoproduction at the energies in the vicinity of the η^{'} threshold, W=1896 MeV (E_{γ}=1447 MeV). Within the framework of a revised ηMAID isobar model, the cusp, in connection with a steep rise of the η^{'} total cross section from its threshold, can only be explained by a strong coupling of the poorly known N(1895)1/2^{-} state to both ηp and η^{'}p. Including the new high-accuracy results in the ηMAID fit to available η and η^{'} photoproduction data allows the determination of the N(1895)1/2^{-} properties.
The double polarization observable E and the helicity dependent cross sections σ_{1/2} and σ_{3/2} were measured for η photoproduction from quasifree protons and neutrons. The circularly polarized ...tagged photon beam of the A2 experiment at the Mainz MAMI accelerator was used in combination with a longitudinally polarized deuterated butanol target. The almost 4π detector setup of the Crystal Ball and TAPS is ideally suited to detect the recoil nucleons and the decay photons from η→2γ and η→3π^{0}. The results show that the narrow structure previously observed in η photoproduction from the neutron is only apparent in σ_{1/2} and hence, most likely related to a spin-1/2 amplitude. Nucleon resonances that contribute to this partial wave in η production are only N 1/2^{-} (S_{11}) and N 1/2^{+} (P_{11}). Furthermore, the extracted Legendre coefficients of the angular distributions for σ_{1/2} are in good agreement with recent reaction model predictions assuming a narrow resonance in the P_{11} wave as the origin of this structure.
Starting from glyoxal, 1,3-diarylimidazolinium chlorides
3 were obtained in a three-step sequence
via the diimines (
1) and ethylene diamine dihydrochlorides (
2). Reduction of ...1,3-diarylimidazolinium chlorides (
3) with lithium alumnium hydride furnished the 1,3-diarylimidazolidines (
4) while their deprotonation with potassium hydride in thf gave access to stable carbenes (1,3-diarylimidazolin-2-ylidenes,
5). Similarly substituted imidazol-2-ylidenes are described for comparison.
Convenient syntheses are presented for a series of imidazole derived carbenes and fully reduced imidazolindines beginning with readily accessible α-diimine precursors. The spectroscopic and structural properties of the imidazole ring systems are compared with one another.
Precise helicity-dependent cross sections and the double-polarization observable E were measured for η photoproduction from quasifree protons and neutrons bound in the deuteron. The η → 2γ and η → ...3π0 → 6γ decay modes were used to optimize the statistical quality of the data and to estimate systematic uncertainties. The measurement used the A2 detector setup at the tagged photon beam of the electron accelerator MAMI in Mainz. A longitudinally polarized deuterated butanol target was used in combination with a circularly polarized photon beam from bremsstrahlung of a longitudinally polarized electron beam. The reaction products were detected with the electromagnetic calorimeters Crystal Ball and TAPS, which covered 98% of the full solid angle. The results show that the narrow structure observed earlier in the unpolarized excitation function of η photoproduction off the neutron appears only in reactions with antiparallel photon and nucleon spin (σ1/2). It is absent for reactions with parallel spin orientation (σ3/2) and thus very probably related to partial waves with total spin 1/2. The behavior of the angular distributions of the helicity-dependent cross sections was analyzed by fitting them with Legendre polynomials. The results are in good agreement with a model from the Bonn-Gatchina group, which uses an interference of P11 and S11 partial waves to explain the narrow structure.
Helium single ionization by 3.6 meV/u Nisup 24+ impact was explored in a kinematically complete experiment by combining a high-resolution recoil-ion momentum spectrometer with a novel 4pi low-energy ...electron analyzer. More than 90% of the soft electrons'' (ital Esub ital eapprox lt50 eV) are ejected in the forward direction in agreement with classical-trajectory Monte Carlo predictions. The electron longitudinal momentum is not balanced by the longitudinal momentum change of the projectile but mainly by the backwards recoiling Hesup 1+ ion. Energy losses of the 0.2 GeV projectiles as small as Deltaital Esub ital P/ital Esub ital P=3.4times10sup minus7 are observable.
Here, the data available from the A2 Collaboration at MAMI were analyzed to select the γp → π0ηp reaction on an event-by-event basis, which allows for partial-wave analyses of three-body final states ...to obtain more reliable results, compared to fits to measured distributions. These data provide the world’s best statistical accuracy in the energy range from threshold to Eγ = 1.45 GeV, allowing a finer energy binning in the measurement of all observables needed for understanding the reaction dynamics. The results obtained for the measured observables are compared to existing models, and the impact from the new data is checked by the fit with the revised Mainz model.
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