1,653 research outputs found
New Universality Classes for Two-Dimensional -Models
We argue that the two-dimensional -invariant lattice -model
with mixed isovector/isotensor action has a one-parameter family of nontrivial
continuum limits, only one of which is the continuum -model constructed
by conventional perturbation theory. We test the proposed scenario with a
high-precision Monte Carlo simulation for on lattices up to , using a Wolff-type embedding algorithm. [CPU time 7 years IBM
RS-6000/320H] The finite-size-scaling data confirm the existence of the
predicted new family of continuum limits. In particular, the and
-vector models do not lie in the same universality class.Comment: 10 pages (includes 2 figures), 211176 bytes Postscript,
NYU-TH-93/07/03, IFUP-TH 34/9
Economic and Religious Choice: A Case-Study from Early Christian Communities
The aim of this paper is to elaborate an evaluative framework of religious choice within the early Christian communities reconstructed through the narrative of a New Testament Epistle, 2Peter, based on an economic approach to moral dilemmas identified in this context. Thus the work concentrates on the stances, attitudes and social practices of deviant members who engaged in free-riding within early Christian congregations and were exposed to serious self-control problems. In our attempt to employ economic theories of religion, we are in a position to better assess the efficiency of early Christian responses to the entry of competing groups in the religious market of this era, as well as to identify and explore the sort of criteria that determine the intertemporal choices of distinct religious actors.choice and markets, religious consumption, free-riding
Learning in a Landscape: Simulation-building as Reflexive Intervention
This article makes a dual contribution to scholarship in science and
technology studies (STS) on simulation-building. It both documents a specific
simulation-building project, and demonstrates a concrete contribution to
interdisciplinary work of STS insights. The article analyses the struggles that
arise in the course of determining what counts as theory, as model and even as
a simulation. Such debates are especially decisive when working across
disciplinary boundaries, and their resolution is an important part of the work
involved in building simulations. In particular, we show how ontological
arguments about the value of simulations tend to determine the direction of
simulation-building. This dynamic makes it difficult to maintain an interest in
the heterogeneity of simulations and a view of simulations as unfolding
scientific objects. As an outcome of our analysis of the process and
reflections about interdisciplinary work around simulations, we propose a
chart, as a tool to facilitate discussions about simulations. This chart can be
a means to create common ground among actors in a simulation-building project,
and a support for discussions that address other features of simulations
besides their ontological status. Rather than foregrounding the chart's
classificatory potential, we stress its (past and potential) role in discussing
and reflecting on simulation-building as interdisciplinary endeavor. This chart
is a concrete instance of the kinds of contributions that STS can make to
better, more reflexive practice of simulation-building.Comment: 37 page
Some Remarks about the Complexity of Epidemics Management
Recent outbreaks of Ebola, H1N1 and other infectious diseases have shown that
the assumptions underlying the established theory of epidemics management are
too idealistic. For an improvement of procedures and organizations involved in
fighting epidemics, extended models of epidemics management are required. The
necessary extensions consist in a representation of the management loop and the
potential frictions influencing the loop. The effects of the non-deterministic
frictions can be taken into account by including the measures of robustness and
risk in the assessment of management options. Thus, besides of the increased
structural complexity resulting from the model extensions, the computational
complexity of the task of epidemics management - interpreted as an optimization
problem - is increased as well. This is a serious obstacle for analyzing the
model and may require an additional pre-processing enabling a simplification of
the analysis process. The paper closes with an outlook discussing some
forthcoming problems
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