2,187 research outputs found
Optimization and design of three-dimensional aerodynamic configurations of arbitrary shape by a vortex lattice method
A new method based on vortex lattice theory has been developed which can be applied to the combined analysis, induced drag optimization, and aerodynamic design of three-dimensional configurations of arbitrary shape. Geometric and aerodynamic constraints can be imposed on both the optimization and the design process. The method is compared with several known analytical solutions and is applied to several different design and optimization problems, including formation flight and wingtip fins for the Boeing KC-135 tanker airplane. Good agreement has been observed between the theoretical predictions and the wind tunnel test results for the KC-135 modification
Demografischer Wandel - Japans Strategien
Der demografische Wandel beschleunigt sich allmählich. Als eine der
wichtigsten gesellschaftlichen Entwicklungen unseres Jahrhunderts
charakterisieren ihn zunehmend deutliche Verschiebungen in vielen
Bevölkerungsstrukturen. Dies stellt immer mehr Länder vor eine Reihe
unterschiedlicher Herausforderungen. Nicht nur wirkungsstarke sozialpolitische
Konsequenzen können mittlerweile abgesehen werden. Viele Fakten sprechen
dafür, dass der demografische Wandel auch einen tief liegenden
makroökonomischen Strukturwandel hervorrufen wird. In Japan ist die
Veränderung durch den demografischen Wandel besonders fortgeschritten und
intensiv. Sie ist in weiten Teilen zudem charakteristisch für die Umwälzungen,
die auf viele andere Industriestaaten in absehbarer Zeit zukommen werden. In
der vorliegenden Arbeit wird mit dem Ansatz der wissenschaftlichen
Zukunftsforschung ein Bogen von der internationalen Dimension des
demografischen Wandels über die extremen Ausprägungen in Japan bis hin zu
einzelnen Strategien der japanischen Regierung gespannt. Es wird aufgezeigt,
warum das Zusammenspiel der drei demografischen Variablen Geburtenrate,
Lebenserwartung und Migration in Japan zu einem Ungleichgewicht führt, und
befunden, dass die verfolgten strategischen Ansätze um dieses Ungleichgewicht
auszugleichen bisher noch deutlich zu kurz greifen
Single photon thermal ionization of C60
We report on experiments which show that C60 can ionize in an indirect, quasi-thermal boiloff process
after absorption of a single photon. The process involves a large number of incoherently excited valence
electrons and yields electron spectra with a Boltzmann distribution with temperatures exceeding 10^4 K.
It is expected to be present for other molecules and clusters with a comparatively large number of valence
electrons. The astrophysical consequences are briefly discussed
The brattleboro rat displays a natural deficit in social discrimination that is restored by clozapine and a neurotensin analog.
Cognitive deficits in schizophrenia are a major source of dysfunction for which more effective treatments are needed. The vasopressin-deficient Brattleboro (BRAT) rat has been shown to have several natural schizophrenia-like deficits, including impairments in prepulse inhibition and memory. We investigated BRAT rats and their parental strain, Long-Evans (LE) rats, in a social discrimination paradigm, which is an ethologically relevant animal test of cognitive deficits of schizophrenia based upon the natural preference of animals to investigate conspecifics. We also investigated the effects of the atypical antipsychotic, clozapine, and the putative antipsychotic, PD149163, a brain-penetrating neurotensin-1 agonist, on social discrimination in these rats. Adult rats were administered saline or one of the three doses of clozapine (0.1, 1.0, or 10 mg/kg) or PD149163 (0.1, 0.3, or 1.0 mg/kg), subcutaneously. Following drug administration, adult rats were exposed to a juvenile rat for a 4-min learning period. Animals were then housed individually for 30 min and then simultaneously exposed to the juvenile presented previously and a new juvenile for 4 min. Saline-treated LE rats, but not BRAT rats, exhibited intact social discrimination as evidenced by greater time spent exploring the new juvenile. The highest dose of clozapine and the two highest doses of PD149163 restored social discrimination in BRAT rats. These results provide further support for the utility of the BRAT rat as a genetic animal model relevant to schizophrenia and drug discovery. The potential of neurotensin agonists as putative treatments for cognitive deficits of schizophrenia was also supported
NEXAFS spectroscopy and site-specific fragmentation of N -methylformamide, N,N -dimethylformamide, and N,N -dimethylacetamide
Near-edge X-ray absorption fine-structure (NEXAFS) spectra measured at the C, N, and O K-edges
for three molecules containing the amide moiety, N-methylformamide (HCONHCH3), N,Ndimethylformamide
(HCON(CH3)2), and N,N-dimethylacetamide (CH3CON(CH3)2) are presented.
These molecules have similar structures and differ by the number of methyl groups located at the
molecular ends. The fragmentation of these molecules after resonant excitation at different K-edge
resonances is also investigated, using a 3D-ion imaging time-of-flight spectrometer. A comparison
between the molecules with respect to the relative contributions of the fragments created upon
excitation at distinct resonances reveals site-specific fragmentation. Further information about the
character of the core-excitation and dissociation process is obtained from the angular distributions of
the ion fragments
Images of psychiatry and psychiatrists.
OBJECTIVE: This study surveyed medical teaching faculty to determine their attitudes toward psychiatry and psychiatrists. METHOD: We conducted a multisite survey of a probability sample of 1057 teaching medical faculty members from 15 academic teaching centers in the United Kingdom, Europe, and Asia stratified by early, middle, and late career stage. The average response rate across countries was 65%. RESULTS: The outstanding findings were that 90% of respondents considered that psychiatrists were not good role models for medical students, 84% thought psychiatric patients were unsuitable to be treated outside of specialized facilities, and 73% thought psychiatric patients were emotionally draining. We noted statistically significant differences by country, gender, career stage, and specialty. CONCLUSION: These results highlight why recruitment into psychiatry is problematic in many countries and suggest that greater attention should be given to improving the perception of psychiatrists as good role models and the efficacy of psychiatric treatments
Photoionization in the time and frequency domain
Ultrafast processes in matter, such as the electron emission following light
absorption, can now be studied using ultrashort light pulses of attosecond
duration (s) in the extreme ultraviolet spectral range. The lack of
spectral resolution due to the use of short light pulses may raise serious
issues in the interpretation of the experimental results and the comparison
with detailed theoretical calculations. Here, we determine photoionization time
delays in neon atoms over a 40 eV energy range with an interferometric
technique combining high temporal and spectral resolution. We spectrally
disentangle direct ionization from ionization with shake up, where a second
electron is left in an excited state, thus obtaining excellent agreement with
theoretical calculations and thereby solving a puzzle raised by seven-year-old
measurements. Our experimental approach does not have conceptual limits,
allowing us to foresee, with the help of upcoming laser technology, ultra-high
resolution time-frequency studies from the visible to the x-ray range.Comment: 5 pages, 4 figure
Experimental Verification of the Chemical Sensitivity of Two-Site Double Core-Hole States Formed by an X-ray FEL
We have performed X-ray two-photon photoelectron spectroscopy (XTPPS) using
the Linac Coherent Light Source (LCLS) X-ray free-electron laser (FEL) in order
to study double core-hole (DCH) states of CO2, N2O and N2. The experiment
verifies the theory behind the chemical sensitivity of two-site (ts) DCH states
by comparing a set of small molecules with respect to the energy shift of the
tsDCH state and by extracting the relevant parameters from this shift.Comment: 11 pages, 2 figure
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