566 research outputs found
Microduplications encompassing the Sonic hedgehog limb enhancer ZRS are associated with Haas-type polysyndactyly and Laurin-Sandrow syndrome
Laurin-Sandrow syndrome (LSS) is a rare autosomal dominant disorder characterized by polysyndactyly of hands and/or feet, mirror image duplication of the feet, nasal defects, and loss of identity between fibula and tibia. The genetic basis of LSS is currently unknown. LSS shows phenotypic overlap with Haas-type polysyndactyly (HTS) regarding the digital phenotype. Here we report on five unrelated families with overlapping microduplications encompassing the Sonic hedgehog (SHH) limb enhancer ZPA regulatory sequence (ZRS) on chromosome 7q36. Clinically, the patients show polysyndactyly phenotypes and various types of lower limb malformations ranging from syndactyly to mirror image polydactyly with duplications of the fibulae. We show that larger duplications of the ZRS region (>80 kb) are associated with HTS, whereas smaller duplications (<80 kb) result in the LSS phenotype. On the basis of our data, the latter can be clearly distinguished from HTS by the presence of mirror image polysyndactyly of the feet with duplication of the fibula. Our results expand the clinical phenotype of the ZRS-associated syndromes and suggest that smaller duplications (<80 kb) are associated with a more severe phenotype. In addition, we show that these small microduplications within the ZRS region are the underlying genetic cause of Laurin-Sandrow syndrome
On a universal photonic tunnelling time
We consider photonic tunnelling through evanescent regions and obtain general
analytic expressions for the transit (phase) time (in the opaque barrier
limit) in order to study the recently proposed ``universality'' property
according to which is given by the reciprocal of the photon frequency.
We consider different physical phenomena (corresponding to performed
experiments) and show that such a property is only an approximation. In
particular we find that the ``correction'' factor is a constant term for total
internal reflection and quarter-wave photonic bandgap, while it is
frequency-dependent in the case of undersized waveguide and distributed Bragg
reflector. The comparison of our predictions with the experimental results
shows quite a good agreement with observations and reveals the range of
applicability of the approximated ``universality'' property.Comment: RevTeX, 8 pages, 4 figures, 1 table; subsection added with a new
experiment analyzed, some other minor change
Tunneling Violates Special Relativity
Experiments with evanescent modes and tunneling particles have shown that i)
their signal velocity may be faster than light, ii) they are described by
virtual particles, iii) they are nonlocal and act at a distance, iv)
experimental tunneling data of phonons, photons, and electrons display a
universal scattering time at the tunneling barrier front, and v) the properties
of evanescent, i.e. tunneling modes is not compatible with the special theory
of relativity
Transmission time of wave packets through tunneling barriers
The transmission of wave packets through tunneling barriers is studied in
detail by the method of quantum molecular dynamics. The distribution function
of the times describing the arrival of a tunneling packet in front of and
behind a barrier and the momentum distribution function of the packet are
calculated. The behavior of the average coordinate of a packet, the average
momentum, and their variances is investigated. It is found that under the
barrier a part of the packet is reflected and a Gaussian barrier increases the
average momentum of the transmitted packet and its variance in momentum space.Comment: 23 pages, 5 figure
Quantum Tunneling in the Wigner Representation
Time dependence for barrier penetration is considered in the phase space. An
asymptotic phase-space propagator for nonrelativistic scattering on a one -
dimensional barrier is constructed. The propagator has a form universal for
various initial state preparations and local potential barriers. It is
manifestly causal and includes time-lag effects and quantum spreading. Specific
features of quantum dynamics which disappear in the standard semi-classical
approximation are revealed. The propagator may be applied to calculation of the
final momentum and coordinate distributions, for particles transmitted through
or reflected from the potential barrier, as well as for elucidating the
tunneling time problem.Comment: 18 pages, LATEX, no figure
Possibility of the tunneling time determination
We show that it is impossible to determine the time a tunneling particle
spends under the barrier. However, it is possible to determine the asymptotic
time, i.e., the time the particle spends in a large area including the barrier.
We propose a model of time measurements. The model provides a procedure for
calculation of the asymptotic tunneling and reflection times. The model also
demonstrates the impossibility of determination of the time the tunneling
particle spends under the barrier. Examples for delta-form and rectangular
barrier illustrate the obtained results.Comment: 8 figure
Conditional probabilities in quantum theory, and the tunneling time controversy
It is argued that there is a sensible way to define conditional probabilities
in quantum mechanics, assuming only Bayes's theorem and standard quantum
theory. These probabilities are equivalent to the ``weak measurement''
predictions due to Aharonov {\it et al.}, and hence describe the outcomes of
real measurements made on subensembles. In particular, this approach is used to
address the question of the history of a particle which has tunnelled across a
barrier. A {\it gedankenexperiment} is presented to demonstrate the physically
testable implications of the results of these calculations, along with graphs
of the time-evolution of the conditional probability distribution for a
tunneling particle and for one undergoing allowed transmission. Numerical
results are also presented for the effects of loss in a bandgap medium on
transmission and on reflection, as a function of the position of the lossy
region; such loss should provide a feasible, though indirect, test of the
present conclusions. It is argued that the effects of loss on the pulse {\it
delay time} are related to the imaginary value of the momentum of a tunneling
particle, and it is suggested that this might help explain a small discrepancy
in an earlier experiment.Comment: 11 pages, latex, 4 postscript figures separate (one w/ 3 parts
Time of arrival in the presence of interactions
We introduce a formalism for the calculation of the time of arrival t at a
space point for particles traveling through interacting media. We develop a
general formulation that employs quantum canonical transformations from the
free to the interacting cases to construct t in the context of the Positive
Operator Valued Measures. We then compute the probability distribution in the
times of arrival at a point for particles that have undergone reflection,
transmission or tunneling off finite potential barriers. For narrow Gaussian
initial wave packets we obtain multimodal time distributions of the reflected
packets and a combination of the Hartman effect with unexpected retardation in
tunneling. We also employ explicitly our formalism to deal with arrivals in the
interaction region for the step and linear potentials.Comment: 20 pages including 5 eps figure
Footprints- In the Footprints of Squier and Davis: Archeological Fieldwork in Ross County, Ohio
TABLE OF CONTENTS
Acknowledgements....................................................................iList of Tables...................................................................vii List of Figures...................................................................ix Contributors .........................................................................xiii
Chapter 1
In the Footprints of Squier and Davis : Archeological
Fieldwork in Ross County, Ohio
Mark J. Lynott................................................................................1 Previous Studies in Ohio ...................................................1 Hopewell Studies Today ................................................................4 Recent Field Research ..........................................................................6 Goal of this Volume ................................................................................12
Chapter 2
In Non-mound Space at the Hopewell Mound Group
Jennifer Pederson Weinberger .........................................13 Geophysical Survey .......................................................15Western Village Area.....................................................................16 Near the East Village .....................................................................18 Central Area ............................................................................19 Discussion .......................................................................................19
Chapter 3
Field Studies of the Octagon and Great Circle, High Bank Earthworks Ross County, Ohio
N’omi B. Greber and Orrin C. Shane III ..............................................23 Excavations at the Octagon ............................................................25 Geophysics at the Great Circle ............................................................30 Excavations at the Great Circle ..........................................................33 Radiocarbon Assays ...........................................................................41 Comments ....................................................................................44 Addendum ..........................................................................................46
Chapter 4
Spruce Hill Earthworks: The 1995-1996 National Park Service Investigations
Bret J. Ruby .............................................................................................49 Background .......................................................................................49 The Spruce Hill Earthworks .......................................................................49 Spruce Hill Revisited ......................................................................53 The 1995-1996 National Park Service Investigations ............................53 Discussion and Conclusions ..............................................................61
Chapter 5
Falling Through a Crack in the Core: The Surprise and Demise of Anderson Earthwork
William H. Pickard and Jeffrey W. Weinberger ........................................ 67 History and Setting ..................................................................................68 1993 Excavations ..................................................................................70 Discussion ..............................................................................................72 Conclusion ............................................................................................74
Chapter 6
Middle Woodland and Other Settlement Remains in the Overly Tract Near The Hopeton Earthwork, Ross County, Ohio
William S. Dancey .....................................................................................................77 Research Design.............................................................................77 Artifact Categories and their Distributions..............................................80 Discussion............................................................................................92
Chapter 7
Hopewell Occupation at the Hopeton Earthworks: Large Scale Surface Survey Using GPS Technology
Jarrod Burks and Dawn Walter Gagliano................................................97 The Survey Area ................................................................................98 Survey Methodology .............................................................................99 Survey Results ...................................................................................99 The Surface Data: A Siteless Approach .................................................103 Discussion and Conclusion .........................................................................106 Notes ...................................................................................................107
Chapter 8
Hopewellian Centers in Context: Investigations In and Around the Hopeton Earthworks
Bret J. Ruby And Mark J. Lynott .................................................................109 Surface Survey ......................................................................................110 Redwing Site ...........................................................................................111 Comparisons .........................................................................................118 Conclusions ......................................................................................122
Chapter 9
Searching for Hopewell Settlements: The Triangle Site at the Hopeton Earthworks
Mark Lynott ...................................................................................... 125 Field Investigations ............................................................................127 Geophysical Survey ............................................................................128 1998 Season ....................................................................................128 Features, Artifacts and Radiocarbon Dating ........................................130 Animal Remains ...............................................................................137 Plant Remains ................................................................................138 Interpretations ..............................................................................139
Chapter 10
Geophysical Investigations at the Hopeton Earthworks
John Weymouth, Bruce Bevan, and Rinita Dalan ...............................145 The Cesium Gradiometer Survey ...........................................................146 Cesium Gradiometer Results ...................................................................146 Geoscan Instrument Surveys ..............................................................148 Comparison of Cesium Magnetic and Resistance Data ........................148 Small Circles...........................................................................................149 Trench Excavations ...................................................................................149 Discussion ................................................................................................152 Conclusions ......................................................................................157
Chapter 11
Archeological and Geoarcheological Study of the Rectangular Enclosure at the Hopeton Works
Mark J. Lynott and Rolfe D. Mandel ......................................................159 The Study of the Rectangular Earthwork ................................................161 Geophysical Survey ..............................................................................163 Trench Excavations .............................................................................164 Chronology ........................................................................................170 Geoarcheological Analysis of Trench 1 .................................................172 Interpretations ................................................................................174
Chapter 12
Ohio Hopewell Ritual Craft Production
Katherine A. Spielmann ............................................................ 179Raw Material Procurement ....................................................................180 Hopewell Crafting ................................................................................181 Deposition ...........................................................................................186 Conclusions ....................................................................................188
References Cited .....................................................................................................18
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