2,812 research outputs found
Interminiband Rabi oscillations in biased semiconductor superlattices
Carrier dynamics at energy level anticrossings in biased semiconductor
superlattices, was studied in the time domain by solving the time-dependent
Schroedinger equation. The resonant nature of interminiband Rabi oscillations
has been explicitly demonstrated to arise from interference of intrawell and
Bloch oscillations. We also report a simulation of direct Rabi oscillations
across three minibands, in the high field regime, due to interaction between
three strongly coupled minibands.Comment: 13 pages, 16 figure
Policy instruments in the Common Agricultural Policy
Policy changes in the Common Agricultural Policy (CAP) can be explained in terms of the exhaustion and long-term contradictions of policy instruments. Changes in policy instruments have reoriented the policy without any change in formal Treaty goals. The social and economic efficacy of instruments in terms of evidence-based policy analysis was a key factor in whether they were delegitimized. The original policy instruments were generally dysfunctional, but reframing the policy in terms of a multifunctionality paradigm permitted the development of more efficacious instruments. A dynamic interaction takes place between the instruments and policy informed by the predominant discourses
Estimation of Diversity and Community Structure Through Restriction-Fragment-Length-Polymorphism Distribution Analysis of Bacterial 16s Ribosomal-RNA Genes from a Microbial Mat at an Active, Hydrothermal Vent System, Loihi Seamount, Hawaii
PCR was used to amplify (eu)bacterial small-subunit (16S) rRNA genes from total-community genomic DNA. The source of total-community genomic DNA used for this culture-independent analysis was the microbial mats from a deep-sea, hydrothermal vent system, Pele\u27s Vents, located at Loihi Seamount, Hawaii. Oligonucleotides complementary to conserved regions in the 16S rRNA-encoding DNA (rDNA) of bacteria were used to direct the synthesis of PCR products, which were then subcloned by blunt-end ligation into phagemid vector pBluescript II. Restriction fragment length polymorphism patterns, created by using tandem tetrameric restriction endonucleases, revealed the presence of 12 groups of 16S rRNA genes representing discrete operational taxonomic units (OTUs). The rank order abundance of these putative OTUs was measured, and the two most abundant OTUs accounted for 72.9% of all of the 16S rDNA clones. Among the remaining 27.1% of the 16S rDNA clones, none of the 10 OTUs was represented by more than three individual clones. The cumulative OTU distribution for 48 bacterial 16S rDNA clones demonstrated that the majority of taxa represented in the clone library were detected, a result which we assume to be an estimate of the diversity of bacteria in the native hydrothermal vent habitat. 16S rDNA fingerprinting of individual clones belonging to particular OTUs by using an oligonucleotide probe that binds to a universally conserved region of the 16S rDNA fragments was conducted to confirm OTU specificity and 16S rDNA identity
Independent analysis of the orbits of Pioneer 10 and 11
Independently developed orbit determination software is used to analyze the
orbits of Pioneer 10 and 11 using Doppler data. The analysis takes into account
the gravitational fields of the Sun and planets using the latest JPL
ephemerides, accurate station locations, signal propagation delays (e.g., the
Shapiro delay, atmospheric effects), the spacecrafts' spin, and maneuvers. New
to this analysis is the ability to utilize telemetry data for spin, maneuvers,
and other on-board systematic effects. Using data that was analyzed in prior
JPL studies, the anomalous acceleration of the two spacecraft is confirmed. We
are also able to put limits on any secondary acceleration (i.e., jerk) terms.
The tools that were developed will be used in the upcoming analysis of recently
recovered Pioneer 10 and 11 Doppler data files.Comment: 22 pages, 5 figures; accepted for publication in IJMP
The Puzzle of the Flyby Anomaly
Close planetary flybys are frequently employed as a technique to place
spacecraft on extreme solar system trajectories that would otherwise require
much larger booster vehicles or may not even be feasible when relying solely on
chemical propulsion. The theoretical description of the flybys, referred to as
gravity assists, is well established. However, there seems to be a lack of
understanding of the physical processes occurring during these dynamical
events. Radio-metric tracking data received from a number of spacecraft that
experienced an Earth gravity assist indicate the presence of an unexpected
energy change that happened during the flyby and cannot be explained by the
standard methods of modern astrodynamics. This puzzling behavior of several
spacecraft has become known as the flyby anomaly. We present the summary of the
recent anomalous observations and discuss possible ways to resolve this puzzle.Comment: 6 pages, 1 figure. Accepted for publication by Space Science Review
Nurses\u27 Alumnae Association Bulletin, May 1960
Accreditation of Programs in Nursing
Alumnae Meetings, 1959
Committee Reports
Greetings from the President
Highlights from first issue of Alumnae Bulletin
Living in the new nurses residence
Lost Members
Marriages
Necrology
New Arrivals
Notices
Personal Items of Interest
Report of the School of Nursing and Nursing Services
Staff Nurses Association
Student Activities
Year of tremendous growth and expansio
Recommended from our members
Study of the phase transition dynamics of the L to H transition
A highly radiating zone (MARFE) just above the divertor X-point has been used to access the marginal transition regime P{sub sep} {approx} P{sub thres} to study the existence of a critical point for the L to H transition. Phase transition models predict that at the critical point, the transition duration increases and the plasma parameters vary continuously between L-mode and H-mode. In these experiments, the L to H transition duration increased 50--100 times over fast transitions. However, the evolution of E{sub r} shear, edge density gradient, H-mode pedestal, and fluctuations is essentially unchanged from that in fast transitions. The only difference is in the speed with which and the degree to which the fluctuation amplitudes are transiently reduced. This difference is understandable in terms of the time scales for fluctuation amplitude reduction ({le} 100 {micro}s) and edge pressure gradient increase (several ms), provided the edge fluctuations are pressure-gradient driven
Field-dependent anisotropic magnetoresistance and planar Hall effect in epitaxial magnetite thin films
A systematic study of the temperature and magnetic field dependence of the
longitudinal and transverse resistivities of epitaxial thin films of magnetite
(Fe3O4) is reported. The anisotropic magnetoresistance (AMR) and the planar
Hall effect (PHE) are sensitive to the in-plane orientation of current and
magnetization with respect to crystal axes in a way consistent with the cubic
symmetry of the system. We also show that the AMR exhibit sign reversal as a
function of temperature, and that it shows significant field dependence without
saturation up to 9 T. Our results provide a unified description of the
anisotropic magnetoresistance effects in epitaxial magnetite films and
illustrate the need for a full determination of the resistivity tensor in
crystalline systems
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