167 research outputs found
About the Algebraic Solutions of Smallest Enclosing Cylinders Problems
Given n points in Euclidean space E^d, we propose an algebraic algorithm to
compute the best fitting (d-1)-cylinder. This algorithm computes the unknown
direction of the axis of the cylinder. The location of the axis and the radius
of the cylinder are deduced analytically from this direction. Special attention
is paid to the case d=3 when n=4 and n=5. For the former, the minimal radius
enclosing cylinder is computed algebrically from constrained minimization of a
quartic form of the unknown direction of the axis. For the latter, an
analytical condition of existence of the circumscribed cylinder is given, and
the algorithm reduces to find the zeroes of an one unknown polynomial of degree
at most 6. In both cases, the other parameters of the cylinder are deduced
analytically. The minimal radius enclosing cylinder is computed analytically
for the regular tetrahedron and for a trigonal bipyramids family with a
symmetry axis of order 3.Comment: 13 pages, 0 figure; revised version submitted to publication
(previous version is a copy of the original one of 2010
Evolution of Fields in a Second Order Phase Transition
We analyse the evolution of scalar and gauge fields during a second order
phase transition using a Langevin equation approach. We show that topological
defects formed during the phase transition are stable to thermal fluctuations.
Our method allows the field evolution to be followed throughout the phase
transition, for both expanding and non-expanding Universes. The results verify
the Kibble mechanism for defect formation during phase transitions.Comment: 12 pages of text plus 17 diagrams available on request, DAMTP 94-8
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Dynamic field test of a model levee founded on peaty organic soil using an eccentric mass shaker
A dynamic field test of a model levee was performed to study the behavior of very soft and compressible peaty organic soils that commonly underlie levees in the Sacramento / San Joaquin Delta in northern California. This first-of-its-kind test applied dynamic loads to the levee/peat system using a large eccentric mass shaker mounted on the levee crest. Loads from the shaker and the inertia of the levee section are transmitted to the peaty organic soils as base shear stresses, and rotational demands that manifest as normal pressures at the embankment/peat interface. We seek to characterize the transmission of seismic energy between the underlying soft peat and the overlying, comparatively stiff levee fills. A crucial step in the evaluation of the test data is calculation of the amplitude and phase of shaker forces. We compute the centrifugal force from discretely sampled proximity transducer data using a cosine sweep interpolation function
What Do Men with Lower Urinary Tract Symptoms Expect from a Urologist in Secondary Care?
Purpose: To identify the expectations of men with LUTS referred to a urologist and to study the association between those expectations and satisfaction with the care provided. Methods: In this prospective cohort study, adult men with LUTS completed a questionnaire before their first outpatient appointment, and again at 6 and 12 weeks. The questionnaires included IPSS and OABq-SF, and self-constructed questions on patient expectations, outcome of expectations and satisfaction. Results: Data from 182 participants showed positive expectations about the urologist performing examinations, providing explanations and finding the underlying cause, but mostly neutral expectations for treatment plans and outcomes. Positive treatment expectations were associated with positive expectations about outcomes after physiotherapy, drug treatment and surgery. Higher symptom scores and age were associated with higher expectations about drug treatment. Expectations were subjectively and objectively fulfilled for 66.4% and 27.3%, respectively. Symptom improvement (decrease in IPSS scores) was significantly more in men with objectively fulfilled expectations than in men with no unfulfilled expectations. No significant difference was present between men with subjectively fulfilled expectations and men with unfulfilled expectations. However, satisfaction was significantly higher for patients with subjectively fulfilled expectations at 6 and 12 weeks compared with those who had unfulfilled expectations. Conclusion: Most men referred to a urologist with LUTS do express clear expectations about treatment in secondary care. Patients with higher expectations for treatment outcomes are more likely to expect to receive that treatment. Satisfaction with the care of a urologist is also higher when patients self-report that they receive the treatment they expected
The Effects of Long-Duration Subduction Earthquakes on Inelastic Behavior of Bridge Pile Foundations Subjected to Liquefaction-Induced Lateral Spreading
Effective-stress nonlinear dynamic analyses (NDA) were performed for a large-diameter reinforced concrete (RC) pile in multi-layered liquefiable sloped ground. The objective was to assess the effects of earthquake duration on the combination of inertia and liquefaction-induced lateral spreading. A parametric study was performed using input motions from subduction and crustal earthquakes covering a wide range of motion durations. The NDA results showed that the pile head displacements increased under liquefied conditions, compared to nonliquefied conditions, due to liquefaction-induced lateral spreading. The NDA results were used to develop a displacement-based equivalent static analysis (ESA) method that combines inertial and lateral spreading loads for estimating elastic and inelastic pile demands
First Observation of the Baryon and a New Measurement of the Mass
Using data recorded with the CLEO II and CLEO II.V detector configurations at
the Cornell Electron Storage Rings, we report the first observation and mass
measurement of the charmed baryon, and an updated measurement
of the mass of the baryon. We find
= 231.0 +- 1.1 +- 2.0 MeV, and
= 166.4 +- 0.2 +- 0.3 MeV, where the errors are
statistical and systematic respectively.Comment: 8 pages postscript, also available through
http://w4.lns.cornell.edu/public/CLN
Strong Decays of Strange Quarkonia
In this paper we evaluate strong decay amplitudes and partial widths of
strange mesons (strangeonia and kaonia) in the 3P0 decay model. We give
numerical results for all energetically allowed open-flavor two-body decay
modes of all nsbar and ssbar strange mesons in the 1S, 2S, 3S, 1P, 2P, 1D and
1F multiplets, comprising strong decays of a total of 43 resonances into 525
two-body modes, with 891 numerically evaluated amplitudes. This set of
resonances includes all strange qqbar states with allowed strong decays
expected in the quark model up to ca. 2.2 GeV. We use standard nonrelativistic
quark model SHO wavefunctions to evaluate these amplitudes, and quote numerical
results for all amplitudes present in each decay mode. We also discuss the
status of the associated experimental candidates, and note which states and
decay modes would be especially interesting for future experimental study at
hadronic, e+e- and photoproduction facilities. These results should also be
useful in distinguishing conventional quark model mesons from exotica such as
glueballs and hybrids through their strong decays.Comment: 69 pages, 5 figures, 39 table
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