4,442 research outputs found
A Completion Report of The Alaska Cooperative Wildlife Research Unit
Field data and observational records emphasized three themes
for research: a) behavior of individual animals (by sex and age)
and groups of caribou (by size and composition) in the vicinity of
man-made obstructions, b) reactions of caribou presented with deflection
or choice situations, that is, when in proximity to an alternate
method of passage over or under the pipelines, and c) reaction of
maternal cows and calves when confronting similar structures. The
responses of animals on subsequent encounters with the pipelines were
studied for insights on the learning ability of caribou to pass beneath
or over obstacles.Submitted to: Alyeska Pipeline Service Company, British Petroleum Alaska Inc., and The U.S. Bureau of Sport Fisheries and WildlifeIntroduction -- Historical and Contemporary Importance of the Prudhoe Bay Area to Arctic Caribou Populations -- Study Facilities -- Research Objectives -- Field Procedures -- Results and Discussions -- Summary -- Recommendations -- References Cited -- Appendix A: I. Test of Independence of Two Properties Using the G-test; II. Testing for the Equality of Two Percentages and Independence of Two Properties -- Appendix B -- Appendix
Aerodynamic configuration development of the highly maneuverable aircraft technology remotely piloted research vehicle
The aerodynamic development of the highly maneuverable aircraft technology remotely piloted research vehicle (HiMAT/RPRV) from the conceptual design to the final configuration is presented. The design integrates several advanced concepts to achieve a high degree of transonic maneuverability, and was keyed to sustained maneuverability goals while other fighter typical performance characteristics were maintained. When tests of the baseline configuration indicated deficiencies in the technology integration and design techniques, the vehicle was reconfigured to satisfy the subcritical and supersonic requirements. Drag-due-to-lift levels only 5 percent higher than the optimum were obtained for the wind tunnel model at a lift coefficient of 1 for Mach numbers of up to 0.8. The transonic drag rise was progressively lowered with the application of nonlinear potential flow analyses coupled with experimental data
Bifurcation in Rotational Spectra of Nonlinear AB Molecules
A classical microscopic theory of rovibrational motion at high angular
momenta in symmetrical non-linear molecules AB is derived within the
framework of small oscillations near the stationary states of a rotating
molecule. The full-dimensional analysis including stretching vibrations has
confirmed the existence of the bifurcation predicted previously by means of the
rigid-bender model. The formation of fourfold energy clusters has already been
experimentally verified for HSe and it has been demonstrated in
fully-dimensional quantum mechanical calculations using the MORBID computer
program. We show in the present work that apart from the level clustering, the
bifurcation produces physically important effects including molecular
symmetry-breaking and a transition from the normal mode to the local mode limit
for the stretching vibrations due to rovibrational interaction. The application
of the present theory with realistic molecular potentials to the HTe,
HSe and HS hydrides results in predictions of the bifurcation points
very close to those calculated previously. However for the lighter HO
molecule we find that the bifurcation occurs at higher values of the total
angular momentum than obtained in previous estimations. The present work shows
it to be very unlikely that the bifurcation in HO will lead to clustering
of energy levels. This result is in agreement with recent variational
calculations.Comment: latex, 19 pages including 2 figures provided as *.uu fil
Letter to Philander Chase
S.N. Child thanks Philander Chase for his donation of $15.00 and requests five more to pay off debts until he can earn an income form his new school.https://digital.kenyon.edu/chase_letters/2340/thumbnail.jp
Statistical Mechanics for Unstable States in Gel'fand Triplets and Investigations of Parabolic Potential Barriers
Free energies and other thermodynamical quantities are investigated in
canonical and grand canonical ensembles of statistical mechanics involving
unstable states which are described by the generalized eigenstates with complex
energy eigenvalues in the conjugate space of Gel'fand triplet. The theory is
applied to the systems containing parabolic potential barriers (PPB's). The
entropy and energy productions from PPB systems are studied. An equilibrium for
a chemical process described by reactions is also
discussed.Comment: 14 pages, AmS-LaTeX, no figur
Landau-Zener-St\"uckelberg interferometry in pair production from counterpropagating lasers
The rate of electron-positron pair production in linearly polarized
counter-propagating lasers is evaluated from a recently discovered solution of
the time-dependent Dirac equation. The latter is solved in momentum space where
it is formally equivalent to the Schr\"odinger equation describing a strongly
driven two-level system. The solution is found from a simple transformation of
the Dirac equation and is given in compact form in terms of the
doubly-confluent Heun's function. By using the analogy with the two-level
system, it is shown that for high-intensity lasers, pair production occurs
through periodic non-adiabatic transitions when the adiabatic energy gap is
minimal. These transitions give rise to an intricate interference pattern in
the pair spectrum, reminiscent of the Landau-Zener-St\"uckelberg phenomenon in
molecular physics: the accumulated phase result in constructive or destructive
interference. The adiabatic-impulse model is used to study this phenomenon and
shows an excellent agreement with the exact result.Comment: 22 pages, 7 figure
Wave Mechanics of a Two Wire Atomic Beamsplitter
We consider the problem of an atomic beam propagating quantum mechanically
through an atom beam splitter. Casting the problem in an adiabatic
representation (in the spirit of the Born-Oppenheimer approximation in
molecular physics) sheds light on explicit effects due to non-adiabatic passage
of the atoms through the splitter region. We are thus able to probe the fully
three dimensional structure of the beam splitter, gathering quantitative
information about mode-mixing, splitting ratios,and reflection and transmission
probabilities
State-to-state rotational transitions in H+H collisions at low temperatures
We present quantum mechanical close-coupling calculations of collisions
between two hydrogen molecules over a wide range of energies, extending from
the ultracold limit to the super-thermal region. The two most recently
published potential energy surfaces for the H-H complex, the so-called
DJ (Diep and Johnson, 2000) and BMKP (Boothroyd et al., 2002) surfaces, are
quantitatively evaluated and compared through the investigation of rotational
transitions in H+H collisions within rigid rotor approximation. The
BMKP surface is expected to be an improvement, approaching chemical accuracy,
over all conformations of the potential energy surface compared to previous
calculations of H-H interaction. We found significant differences in
rotational excitation/de-excitation cross sections computed on the two surfaces
in collisions between two para-H molecules. The discrepancy persists over a
large range of energies from the ultracold regime to thermal energies and
occurs for several low-lying initial rotational levels. Good agreement is found
with experiment (Mat\'e et al., 2005) for the lowest rotational excitation
process, but only with the use of the DJ potential. Rate coefficients computed
with the BMKP potential are an order of magnitude smaller.Comment: Accepted by J. Chem. Phy
Recommended from our members
[Abstract] Sentencing intoxicated offenders: does alcoholism excuse drunkenness?
Criminal responsibility is founded on the volitional control of action, yet many offences are committed whilst intoxicated. Alcohol is a widely-used intoxicant known to impair behavioural control and memory, opening the door to claims of partial or absent responsibility. Criminal law rules have developed to resist such claims. In particular, findings of criminal responsibility in intoxicated offenders frequently call on âprior faultâ logic: the intoxicated offender may claim to have been irrational, but culpability can be imported from their earlier, rational choice to consume intoxicants (Robinson, 1985). That drunkenness does not excuse derives from an unforced choice to become drunk. Yet this raises questions over the extent to which an alcoholicâs choice to drink is unforced. Current neurobiological models of addiction stress compulsion as a primary component, bringing into question the volitional nature of continued consumption (Volkow & Fowler, 2000; Dalley, Everitt, & Robbins, 2011). At the same time, some legal scholars have noted that the potentially fatal nature of alcoholic withdrawal could likewise undermine suggestion that consumption is voluntary, drawing analogy to a defence of duress where actions have been forced under the threat of death (Husak, 1999; Yaffe, 2013). We asked 290 UK Magistrates to consider a criminal sentencing scenario in which evidence of a defendantâs state of intoxication at the time of the offence was presented in tandem with information that they were either teetotal, a casual drinker or an alcoholic. We found that intoxication reduced blameworthiness for criminal acts if the offender had no previous experience with alcohol whilst, in direct contrast, intoxication served to aggravate offending if the defendant was an alcoholic. The likelihood of our defendant receiving a reduced sentence was over ten times greater in the event that, though intoxicated, they were not also an alcoholic. Leniency was blocked by alcoholism despite Magistratesâ qualitative responses suggesting its understanding as a generally mitigating factor, revealing a disconnect between expressed opinion and sentencing behaviour in practice. Our results indicate that, far from excusing drunkenness, the state of being an alcoholic is more frequently deemed to aggravate offending, being associated with harsher sentencing even where the offence in question was committed whilst sober
The quality of different types of child care at 10 and 18 months. A comparison between types and factors related to quality.
The quality of care offered in four different types of non-parental child care to 307 infants at 10 months old and 331 infants at 18 months old was compared and factors associated with higher quality were identified. Observed quality was lowest in nurseries at each age point, except that at 18 months they offered more learning activities. There were few differences in the observed quality of care by child-minders, grandparents and nannies, although grandparents had somewhat lower safety and health scores and offered children fewer activities. Cost was largely unrelated to quality of care except in child-minding, where higher cost was associated with higher quality. Observed ratios of children to adults had a significant impact on quality of nursery care; the more infants or toddlers each adult had to care for, the lower the quality of the care she gave them. Mothers' overall satisfaction with their child's care was positively associated with its quality for home-based care but not for nursery settings
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