4,245 research outputs found
SCCRC 1966-1969 Document 23: Memo. No. 9, Robert H. Stoudemire, Staff Consultant, to Members of the Constitutional Revision Committee, December 5, 1967, with enclosed Working Paper No. 11 on County and Municipal Government
SCCRC 1966-1969 Document 20: Memo. No. 6, Robert H. Stoudemire, Staff Consultant, to Members of the Constitutional Revision Committee, October 24, 1967, with enclosed Working Paper No. 7 on Article IV, the Executive Department
Pleistocene and Holocene Carbonate Environments on San Salvador Island, Bahamas: A Field Trip Guide
Although isolated and small in size, San Salvador Island is in many ways a unique place - an all carbonates setting on a small, tectonically stable platform, surrounded by deep oceanic waters, and an historical footnote as the widely accepted first landing site of Christopher Columbus in the New World in 1492. Columbus\u27 stay here was brief, and the major events of subsequent history largely have passed San Salvador by. This is not a tourist island; the natural beauty, floras, and faunas of the Bahamas are well preserved here.
The overview theme of this series of field excursions on San Salvador will be interpretation of paleodepositional environments for the well-exposed Pleistocene and Holocene carbonate rocks that cap the island and recognition of modem analogues from the varied carbonate environments found on the island and its surrounding shelf. Questions of sea level history, diagenetic change, and the surficial processes operating on carbonate island terranes also will be considered. Our trip will begin with a low-attitude overflight to view features of the main Bahama platform enroute to San Salvador, which lies just beyond the eastern edge of the platform.
The field trip leaders all have been working on San Salvador and elsewhere in the Bahamas for the past decade. We have experienced the good and the bad - a pleasant tropical climate, warm and alive marine waters, a generally unspoiled setting, and the friendly Bahamian people, along with sometimes fierce no-see-um attacks, sun-burnt skin, and unexpected soakings from tropical storms. Throughout, the experiences have been rewarding and the challenges of geologic interpretation great. We look forward to sharing some of our findings and experiences with you. Welcome to the Bahamas and San Salvador Island!
See other Smith authored Field Trip Guides of Gerace Research Centre
Effect of magnetic state on the transition in iron: First-principle calculations of the Bain transformation path
Energetics of the fcc () - bcc () lattice transformation by
the Bain tetragonal deformation is calculated for both magnetically ordered and
paramagnetic (disordered local moment) states of iron. The first-principle
computational results manifest a relevance of the magnetic order in a scenario
of the - transition and reveal a special role of the Curie
temperature of -Fe, , where a character of the transformation is
changed. At a cooling down to the temperatures one can expect that
the transformation is developed as a lattice instability whereas for
it follows a standard mechanism of creation and growth of an embryo of the new
phase. It explains a closeness of to the temperature of start of the
martensitic transformation, .Comment: 4 pages, 3 figures, submitted in Phys. Rev. Letter
The structure of causal sets
More often than not, recently popular structuralist interpretations of
physical theories leave the central concept of a structure insufficiently
precisified. The incipient causal sets approach to quantum gravity offers a
paradigmatic case of a physical theory predestined to be interpreted in
structuralist terms. It is shown how employing structuralism lends itself to a
natural interpretation of the physical meaning of causal sets theory.
Conversely, the conceptually exceptionally clear case of causal sets is used as
a foil to illustrate how a mathematically informed rigorous conceptualization
of structure serves to identify structures in physical theories. Furthermore, a
number of technical issues infesting structuralist interpretations of physical
theories such as difficulties with grounding the identity of the places of
highly symmetrical physical structures in their relational profile and what may
resolve these difficulties can be vividly illustrated with causal sets.Comment: 19 pages, 4 figure
Preliminary archaeoentomological analyses of permafrost-preserved cultural layers from the pre-contact Yupâik Eskimo site of Nunalleq, Alaska : implications, potential and methodological considerations
Acknowledgements Site excavation and samples collection were conducted by archaeologists from the University of Aberdeen, with the help of archaeologists and student excavators from the University of Aberdeen University of Alaska Fairbanks and Bryn Mawr College, Kuskokwim Campus, College of Rural Alaska and residents of Quinhagak and Mekoryuk. This study is funded through AHRC grant to the project âUnderstanding Cultural Resilience and Climate Change on the Bering Sea through Yupâik Ecological Knowledge, Lifeways, Learning and Archaeologyâ to Rick Knecht, Kate Britton and Charlotta Hillderal (University of Aberdeen; AH/K006029/1). Thanks are due to Qanirtuuq Inc. and Quinhagak, Alaska for sampling permissions and to entomologists working at the CNC in Ottawa for allowing access to reference collections of beetles, lice and fleas. Yves Bousquet, Ales Smetana and Anthony E. Davies are specially acknowledged for their help with the identification of coleopteran specimens. Finally, we would also like to thank Scott Elias for useful comments on the original manuscript.Peer reviewedPublisher PD
Effect of 17 Days of Bed Rest on Peak Isometric Force and Unloaded Shortening Velocity of Human Soleus Fibers
The purpose of this study was to examine the effect of prolonged bed rest (BR) on the peak isometric force (Po) and unloaded shortening velocity (Vo) of single Ca2+-activated muscle fibers. Soleus muscle biopsies were obtained from eight adult males before and after 17 days of 6° head-down BR. Chemically permeabilized single fiber segments were mounted between a force transducer and position motor, activated with saturating levels of Ca2+, and subjected to slack length steps. Vo was determined by plotting the time for force redevelopment vs. the slack step distance. Gel electrophoresis revealed that 96% of the pre- and 87% of the post-BR fibers studied expressed only the slow type I myosin heavy chain isoform. Fibers with diameter \u3e100 ÎŒm made up only 14% of this post-BR type I population compared with 33% of the pre-BR type I population. Consequently, the post-BR type I fibers (n = 147) were, on average, 5% smaller in diameter than the pre-BR type I fibers (n = 218) and produced 13% less absolute Po. BR had no overall effect on Po per fiber cross-sectional area (Po/CSA), even though half of the subjects displayed a decline of 9â12% in Po/CSA after BR. Type I fiber Vo increased by an average of 34% with BR. Although the ratio of myosin light chain 3 to myosin light chain 2 also rose with BR, there was no correlation between this ratio and Vo for either the pre- or post-BR fibers. In separate fibers obtained from the original biopsies, quantitative electron microscopy revealed a 20â24% decrease in thin filament density, with no change in thick filament density. These results raise the possibility that alterations in the geometric relationships between thin and thick filaments may be at least partially responsible for the elevated Vo of the post-BR type I fibers
Lattice dynamics and structural stability of ordered Fe3Ni, Fe3Pd and Fe3Pt alloys
We investigate the binding surface along the Bain path and phonon dispersion
relations for the cubic phase of the ferromagnetic binary alloys Fe3X (X = Ni,
Pd, Pt) for L12 and DO22 ordered phases from first principles by means of
density functional theory. The phonon dispersion relations exhibit a softening
of the transverse acoustic mode at the M-point in the L12-phase in accordance
with experiments for ordered Fe3Pt. This instability can be associated with a
rotational movement of the Fe-atoms around the Ni-group element in the
neighboring layers and is accompanied by an extensive reconstruction of the
Fermi surface. In addition, we find an incomplete softening in [111] direction
which is strongest for Fe3 Ni. We conclude that besides the valence electron
density also the specific Fe-content and the masses of the alloying partners
should be considered as parameters for the design of Fe-based functional
magnetic materials.Comment: Revised version, accepted for publication in Physical Review
Supergravity p-branes revisited: extra parameters, uniqueness, and topological censorship
We perform a complete integration of the Einstein-dilaton-antisymmetric form
action describing black p-branes in arbitrary dimensions assuming the
transverse space to be homogeneous and possessing spherical, toroidal or
hyperbolic topology. The generic solution contains eight parameters satisfying
one constraint. Asymptotically flat solutions form a five-parametric subspace,
while conditions of regularity of the non-degenerate event horizon further
restrict this number to three, which can be related to the mass and the charge
densities and the asymptotic value of the dilaton. In the case of a degenerate
horizon, this number is reduced by one. Our derivation constitutes a
constructive proof of the uniqueness theorem for -branes with the
homogeneous transverse space. No asymptotically flat solutions with toroidal or
hyperbolic transverse space within the considered class are shown to exist,
which result can be viewed as a demonstration of the topological censorship for
p-branes. From our considerations it follows, in particular, that some
previously discussed p-brane-like solutions with extra parameters do not
satisfy the standard conditions of asymptotic flatness and absence of naked
singularities. We also explore the same system in presence of a cosmological
constant, and derive a complete analytic solution for higher-dimensional
charged topological black holes, thus proving their uniqueness.Comment: Revtex4, no figure
A Note on D-brane - Anti-D-brane Interactions in Plane Wave Backgrounds
We study aspects of the interaction between a D-brane and an anti-D-brane in
the maximally supersymmetric plane wave background of type IIB superstring
theory, which is equipped with a mass parameter mu. An early such study in flat
spacetime (mu=0) served to sharpen intuition about D-brane interactions,
showing in particular the key role of the ``stringy halo'' that surrounds a
D-brane. The halo marks the edge of the region within which tachyon
condensation occurs, opening a gateway to new non-trivial vacua of the theory.
It seems pertinent to study the fate of the halo for non--zero mu. We focus on
the simplest cases of a Lorentzian brane with p=1 and an Euclidean brane with
p=-1, the D--instanton. For the Lorentzian brane, we observe that the halo is
unaffected by the presence of non--zero mu. This most likely extends to other
(Lorentzian) p. For the Euclidean brane, we find that the halo is affected by
non-zero mu. As this is related to subtleties in defining the exchange
amplitude between Euclidean branes in the open string sector, we expect this to
extend to all Euclidean branes in this background.Comment: 14 pages, LaTeX, 2 eps figures. v2: a reference and some clarifying
remarks added; v3: Considerably revised version; halo unaffected by plane
wave background for Lorentzian branes, but Euclidean branes' halo is modifie
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