1,796 research outputs found
Management Skills for the Contemporary College President: A Critical Review
This review of the literature related to the contemporary college president attempted to describe changes to the presidential role during the past 30 years. In addition to describing changes to the role, the review explores the personal, organizational, interpersonal, and leadership skills required for leading a contemporary university. The findings particularly note that with the changing demands for accountability in higher education, presidents are being forced to spend more of their time and be more focused on issues of finance, law, and public interactions. These issues tend to collide in discussions of public policy and within the framework of state legislative proposals. Continued professional development for college presidents is recommended, especially in terms of aligning work place priorities with the institution’s mission
Continuous Loading of a Conservative Trap from an Atomic Beam
We demonstrate the fast accumulation of Cr atoms in a conservative potential
from a magnetically guided atomic beam. Without laser cooling on a cycling
transition, a single dissipative step realized by optical pumping allows to
load atoms at a rate of 2*10^7 1/s in the trap. Within less than 100 ms we
reach the collisionally dense regime, from which we directly produce a
Bose-Einstein condensate with subsequent evaporative cooling. This constitutes
a new approach to degeneracy where, provided a slow beam of particles can be
produced by some means, Bose-Einstein condensation can be reached for species
without a cycling transition.Comment: 4 pages, 4 figure
Evaporation limited loading of an atom trap
Recently, we have experimentally demonstrated a continuous loading mechanism
for an optical dipole trap from a guided atomic beam [1]. The observed
evolution of the number of atoms and temperature in the trap are consequences
of the unusual trap geometry. In the present paper, we develop a model based on
a set of rate equations to describe the loading dynamics of such a mechanism.
We consider the collision statistics in the non-uniform trap potential that
leads to twodimensional evaporation. The comparison between the resulting
computations and experimental data allows to identify the dominant loss process
and suggests ways to enhance the achievable steady-state atom number.
Concerning subsequent evaporative cooling, we find that the possibility of
controlling axial and radial confinement independently allows faster
evaporation ramps compared to single beam optical dipole traps.Comment: 10 pages, 7 figure
Typification and taxonomic status re-eveluation of 15 taxon names within the species complex Cymbella affinis/tumidula/turgidula (Cymbellaceae, Bacillariophyta)
Volume: 53Start Page: 1End Page: 2
Shell Structures and Chaos in Deformed Nuclei and Large Metallic Clusters
A reflection-asymmetric deformed oscillator potential is analysed from the
classical and quantum mechanical point of view. The connection between
occurrence of shell structures and classical periodic orbits is studied using
the ''removal of resonances method'' in a classical analysis. In this
approximation, the effective single particle potential becomes separable and
the frequencies of the classical trajectories are easily determined. It turns
out that the winding numbers calculated in this way are in good agreement with
the ones found from the corresponding quantum mechanical spectrum using the
particle number dependence of the fluctuating part of the total energy. When
the octupole term is switched on it is found that prolate shapes are stable
against chaos whereas spherical and oblate cases become chaotic. An attempt is
made to explain this difference in the quantum mechanical context by looking at
the distribution of exceptional points which results from the matrix structure
of the respective Hamiltonians. In a similar way we analyse the modified
Nilsson model and discuss its consequences for nuclei and metallic clusters.Comment: to appear in Physica Scripta., CNLS-94-02, a talk given at the Nobel
sponsored conference SELMA 94 "New Nuclear Phenomena in the Vicinity of
Closed Shell" (Stockholm and Uppsala, 29 Aug.- 3 Sept. 1994
Spin and orbital frustration in MnSc_2S_4 and FeSc_2S_4
Crystal structure, magnetic susceptibility, and specific heat were measured
in the normal cubic spinel compounds MnSc_2S_4 and FeSc_2S_4. Down to the
lowest temperatures, both compounds remain cubic and reveal strong magnetic
frustration. Specifically the Fe compound is characterized by a Curie-Weiss
temperature \Theta_{CW}= -45 K and does not show any indications of order down
to 50 mK. In addition, the Jahn-Teller ion Fe^{2+} is orbitally frustrated.
Hence, FeSc_2S_4 belongs to the rare class of spin-orbital liquids. MnSc_2S_4
is a spin liquid for temperatures T > T_N \approx 2 K.Comment: 4 pages, to be published in Physical Review Letter
Orbital Magnetism in Small Quantum Dots with Closed Shells
It is found that various kind of shell structure which occurs at specific
values of the magnetic field leads to the disappearance of the orbital
magnetization for particular magic numbers of small quantum dots with an
electron number .Comment: 4 pages, latex file, four figures as postscript files, to appear at
JETP Letters, December 199
Formation of Structure in Snowfields: Penitentes, Suncups, and Dirt Cones
Penitentes and suncups are structures formed as snow melts, typically high in
the mountains. When the snow is dirty, dirt cones and other structures can form
instead. Building on previous field observations and experiments, this work
presents a theory of ablation morphologies, and the role of surface dirt in
determining the structures formed. The glaciological literature indicates that
sunlight, heating from air, and dirt all play a role in the formation of
structure on an ablating snow surface. The present work formulates a
mathematical model for the formation of ablation morphologies as a function of
measurable parameters. The dependence of ablation morphologies on weather
conditions and initial dirt thickness are studied, focusing on the initial
growth of perturbations away from a flat surface. We derive a single-parameter
expression for the melting rate as a function of dirt thickness, which agrees
well with a set of measurements by Driedger. An interesting result is the
prediction of a dirt-induced travelling instability for a range of parameters.Comment: 28 pages, 13 figure
The Randomized Shortened Dental Arch Study: Tooth Loss
The evidence concerning the management of shortened dental arch (SDA) cases is sparse. This multi-center study was aimed at generating data on outcomes and survival rates for two common treatments, removable dental prostheses (RDP) for molar replacement or no replacement (SDA). The hypothesis was that the treatments lead to different incidences of tooth loss. We included 215 patients with complete molar loss in one jaw. Molars were either replaced by RDP or not replaced, according to the SDA concept. First tooth loss after treatment was the primary outcome measure. This event occurred in 13 patients in the RDP group and nine patients in the SDA group. The respective Kaplan-Meier survival rates at 38 months were 0.83 (95% CI: 0.74-0.91) in the RDP group and 0.86 (95% CI: 0.78-0.95) in the SDA group, the difference being non-significant
Short distance behaviour of the effective string
We study the Polyakov loop correlator in the (2+1) dimensional Z_2 gauge
model. An algorithm that we have presented recently, allows us to reach high
precision results for a large range of distances and temperatures, giving us
the opportunity to test predictions of the effective Nambu-Goto string model.
Here we focus on the regime of low temperatures and small distances. In
contrast to the high temperature, large distance regime, we find that our
numerical results are not well described by the two loop-prediction of the
Nambu-Goto model. In addition we compare our data with those for the SU(2) and
SU(3) gauge models in (2+1) dimensions obtained by other authors. We generalize
the result of L\"uscher and Weisz for a boundary term in the interquark
potential to the finite temperature case.Comment: 38 pages, 7 figures, version accepted for publication in JHE
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