44,253 research outputs found
Mutually local fields from form factors
We compare two different methods of computing form factors. One is the well
established procedure of solving the form factor consistency equations and the
other is to represent the field content as well as the particle creation
operators in terms of fermionic Fock operators. We compute the corresponding
matrix elements for the complex free fermion and the Federbush model. The
matrix elements only satisfy the form factor consistency equations involving
anyonic factors of local commutativity when the corresponding operators are
local. We carry out the ultraviolet limit, analyze the momentum space cluster
properties and demonstrate how the Federbush model can be obtained from the
-homogeneous sine-Gordon model. We propose a new class of Lagrangians
which constitute a generalization of the Federbush model in a Lie algebraic
fashion. For these models we evaluate the associated scattering matrices from
first principles, which can alternatively also be obtained in a certain limit
of the homogeneous sine-Gordon models.Comment: 16 pages Late
Archaeology, science-based archaeology and the Mediterranean Bronze Age metals trade
Archaeologists often seem either sceptical of science-based archaeology or baffled by its
results. The underpinnings of science-based archaeology may conflict with social or behavioural
factors unsuited to quantification and grouping procedures. Thus, the interaction between archaeologists
and their science-based colleagues has been less profitable than it might have been. The
main point I consider in this study, and exemplify by considering metals provenance studies in
the Bronze Age Mediterranean, is the relevance and application of the stated aims of science-based
archaeology to the contemporary discipline of archaeology. Whereas most practitioners
today recognize that science-based archaeology has the potential to contribute positively to the
resolution of problems stemming from our field's inadequate and incomplete data resource, I contend
that science and scientific analyses alone cannot adjudicate between cultural possibilities.
Rather they provide analytical data which are likely to be open-ended, subject to multiple social
interpretations, and in need of evaluation by collaborating archaeologists using social theory
Stratigraphy of Tithonian (Ohauan-Puaroan ) marine beds near Port Waikato, New Zealand, and a redescription of Belemnopsis aucklandica (Hochstetter).
Some 1500 m of marine Ohauan and Puaroan strata in the Port Waikato region of New Zealand are restudied in an attempt to resolve lithostratigraphic and biostratigraphic anomalies in published works. New correlations are proposed for some units of the Apotu Group. A lower 650 m siltstone, previously correlated entirely with Kinohaku Siltstone, is here regarded as including the interval Kinohaku Siltstone to Lower Puti Siltstone (new member). The Waiharakeke Conglomerate is not represented in the area by coarse sediments. A thin sandstone unit overlying the Lower Puti Siltstone and previously correlated with Waiharakeke Conglomerate is here correlated with the Ruakiwi Sandstone. The overlying 400 m siltstone, regarded previously as the entire Puti Siltstone, is here recognised as a new member, the Upper Puti Siltstone. The Coleman Conglomerate is much thicker in the region than mapped, and located higher in the sequence. Biostratigraphy is a key element in correlating the sequence with named units to the south. The sequence is mostly siltstone, but sandstone units provide some lithostratigraphic control. Belemnites are almost the only fossils found in the Late Ohauan and Early Puaroan part of the sequence and are important in the Late Puaroan. Formal belemnite zones, based in part on their stratigraphic distributions in other parts of southwest Auckland, are erected. Occasional ammonites provide tie points that correlate the succession with the standard stratigraphic column for the Tethyan realm. Belemnopsis aucklandica (Hochstetter) is redescribed and considered to be of full specific status as is its former subspecies, Belemnopsis trechmanni Stevens. Many pre-adult Belemnopsis aucklandica differ in form from adults, some have been previously identified in the field as Hibolithes. Some earlier identifications of belemnites from the Late Puaroan of Port Waikato are incorrect, most are now included in Belemnopsis aucklandica
Notes on the belemnite content of the Heterian and Ohauan stages at Kawhia Harbour, New Zealand
The belemnite content of the Heterian and Ohauan stages at Kawhia Harbour is described. Six major species or groups are differentiated, each of which ranges through several hundred feet of strata. Other minor elements are also present. Belemnopsis keari Stevens is shown to be present in only a restricted group of beds in the upper part of the Waikutakuta Siltstone, and Belemnopsis alfurica (Boehm) may be present in the upper Waikutakuta Siltstone. A system of informal belemnite zones is suggested. The belemnite succession is well defined throughout most of the Heterian stage, but poorly defined in the Ohauan, and further work is required in the upper and lower parts of this stage
Complex belemnites of the Puaroan (lower-? middle Tithonian) stage in the Port Waikato Region of New Zealand
Belemnite guards range through 2700 feet of Puaroan strata in the Port Waikato region. All are Belemnopsis of the uhligi-complex. Belemnopsis aucklandica aucklandica (Hochstetter) in its most typical form may be restricted to the lower 700 feet of the sequence. Three species are described, together with what may be transitional forms. The morphology of juvenile guards is in marked contrast with that of mature specimens, and development of the adult guard is revealed by examination of internal sections. Some aspects of belemnite paleoecology are discussed. Belemnite biostratigraphy of the area is outlined and the more important fossil localities are described
Integral equations PS-3 and moduli of pants
More than a hundred years ago H.Poincare and V.A.Steklov considered a problem
for the Laplace equation with spectral parameter in the boundary conditions.
Today similar problems for two adjacent domains with the spectral parameter in
the conditions on the common boundary of the domains arises in a variety of
situations: in justification and optimization of domain decomposition method,
simple 2D models of oil extraction, (thermo)conductivity of composite
materials. Singular 1D integral Poincare-Steklov equation with spectral
parameter naturally emerges after reducing this 2D problem to the common
boundary of the domains. We present a constructive representation for the
eigenvalues and eigenfunctions of this integral equation in terms of moduli of
explicitly constructed pants, one of the simplest Riemann surfaces with
boundary. Essentially the solution of integral equation is reduced to the
solution of three transcendent equations with three unknown numbers, moduli of
pants. The discreet spectrum of the equation is related to certain surgery
procedure ('grafting') invented by B.Maskit (1969), D.Hejhal (1975) and
D.Sullivan- W.Thurston (1983).Comment: 27 pages, 13 figure
A Semiclassical Approach to Level Crossing in Supersymmetric Quantum Mechanics
Much use has been made of the techniques of supersymmetric quantum mechanics
(SUSY QM) for studying bound-state problems characterized by a superpotential
. Under the analytic continuation , a pair of
superpartner bound-state problems is transformed into a two-state
level-crossing problem in the continuum. The description of matter-enhanced
neutrino flavor oscillations involves a level-crossing problem. We treat this
with the techniques of supersymmetric quantum mechanics. For the benefit of
those not familiar with neutrino oscillations and their description, enough
details are given to make the rest of the paper understandable. Many other
level-crossing problems in physics are of exactly the same form. Particular
attention is given to the fact that different semiclassical techniques yield
different results. The best result is obtained with a uniform approximation
that explicitly recognizes the supersymmetric nature of the system.Comment: 15 pages, Latex with lamuphys and psfig macros. Talk by first Author
at the UIC "Supersymmetry and Integrable Models Workshop", Chicago, June
12-14, 1997; proceedings to be published in Springer Lecture Notes in
Physics, H. Aratyn et al., eds. This paper also available at
http://nucth.physics.wisc.edu/preprint
Kink Confinement and Supersymmetry
We analyze non-integrable deformations of two-dimensional N=1 supersymmetric
quantum field theories with kink excitations. As example, we consider the
multi-frequency Super Sine Gordon model. At weak coupling, this model is robust
with respect to kink confinement phenomena, in contrast to the purely bosonic
case. If we vary the coupling, the model presents a sequence of phase
transitions, where pairs of kinks disappear from the spectrum. The phase
transitions fall into two classes: the first presents the critical behaviors of
the Tricritical Ising model, the second instead those of the gaussian model. In
the first case, close to the critical point, the model has metastable vacua,
with a spontaneously supersymmetry breaking. When the life-time of the
metastable vacua is sufficiently long, the role of goldstino is given by the
massless Majorana fermion of the Ising model. On the contrary, supersymmetry
remains exact in the phase transition of the second type.Comment: 29 pages, 12 figure
Nonessential functionals in multiobjective optimal control problems
We address the problem of obtaining well-defined criteria for multiple criteria optimal control problems. Necessary and sufficient conditions for an objective functional to be nonessential are proved. The results provide effective tools for determining nonessential objectives in multiobjective optimal control problems
Blended learning for project management
Students studying at postgraduate level should engage in learning on higher cognitive levels such as evaluation and creation. The notion of effective learning at this level is
characterised by the studentâs ability to use acquired knowledge and principles to solve complex problems. Learning theories advocate maximising student engagement
with the learning resources in order to facilitate such effective learning. This can be achieved by addressing the following factors in curriculum design: accessibility,
variety, formative assessment and the development of learning communities. This paper presents work done on a postgraduate level Project Management course to
maximise the factors mentioned above, for example, with the introduction of automatically marked quizzes and the re-structuring of the course content. The
content and delivery of the course was changed from weekly lectures and tutorial sessions (old system) to a web-based blended learning system (new system).
Evaluation of the old and new systems was undertaken using questionnaires. The student evaluation suggests that the new system led to more effective learning. It is
suggested that effective learning can be facilitated by a blended learning system
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