4,314 research outputs found
Tax uniformity as a requirement of justice
Barbara Fried takes the view that uniform taxation-that is, a single rate applicable to all income levels-cannot be defended on any grounds of justice. She goes further by saying that, of all possible rate structures, it might be "the hardest one"? to ground in "a"? theory of fairness. Using the contractarian-constitutional perspective advanced by John Rawls and James Buchanan, this article argues that tax uniformity can be seen as a requirement of justice. After modelling how the political world realistically decides to distribute tax shares (self-interested parties act under a majority constraint), I show how the uniformity principle could emerge from the constitutional contract. In other words, rational individuals would choose uniformity as a procedural constraint under a "veil of uncertainty"?; that is, with limited knowledge regarding their positions under the future application of the rule. Moreover, I elucidate how the uniformity requirement integrates generalized criteria of fairness and efficiency into fiscal politics as it precludes fiscal exploitation and constrains majorities, and their most influential subgroups, to opt for policies in the direction of the Pareto frontier, and as such promotes outcomes acceptable to all participants
IEAD: A Novel One-Line Interface to Query Astronomical Science Archives
In this article I present IEAD, a new interface for astronomical science
databases. It is based on a powerful, yet simple, syntax designed to completely
abstract the user from the structure of the underlying database. The
programming language chosen for its implementation, JavaScript, makes it
possible to interact directly with the user and to provide real-time
information on the parsing process, error messages, and the name resolution of
targets; additionally, the same parsing engine is used for context-sensitive
autocompletion. Ultimately, this product should significantly simplify the use
of astronomical archives, inspire more advanced uses of them, and allow the
user to focus on what scientific research to perform, instead of on how to
instruct the computer to do it.Comment: 13 pages, PASP in pres
Field-control, phase-transitions, and life's emergence
Instances of critical-like characteristics in living systems at each
organizational level as well as the spontaneous emergence of computation
(Langton), indicate the relevance of self-organized criticality (SOC). But
extrapolating complex bio-systems to life's origins, brings up a paradox: how
could simple organics--lacking the 'soft matter' response properties of today's
bio-molecules--have dissipated energy from primordial reactions in a controlled
manner for their 'ordering'? Nevertheless, a causal link of life's macroscopic
irreversible dynamics to the microscopic reversible laws of statistical
mechanics is indicated via the 'functional-takeover' of a soft magnetic
scaffold by organics (c.f. Cairns-Smith's 'crystal-scaffold'). A
field-controlled structure offers a mechanism for bootstrapping--bottom-up
assembly with top-down control: its super-paramagnetic components obey
reversible dynamics, but its dissipation of H-field energy for aggregation
breaks time-reversal symmetry. The responsive adjustments of the controlled
(host) mineral system to environmental changes would bring about mutual
coupling between random organic sets supported by it; here the generation of
long-range correlations within organic (guest) networks could include SOC-like
mechanisms. And, such cooperative adjustments enable the selection of the
functional configuration by altering the inorganic network's capacity to assist
a spontaneous process. A non-equilibrium dynamics could now drive the
kinetically-oriented system towards a series of phase-transitions with
appropriate organic replacements 'taking-over' its functions.Comment: 54 pages, pdf fil
A general formulation of Bead Models applied to flexible fibers and active filaments at low Reynolds number
This contribution provides a general framework to use Lagrange multipliers
for the simulation of low Reynolds number fiber dynamics based on Bead Models
(BM). This formalism provides an efficient method to account for kinematic
constraints. We illustrate, with several examples, to which extent the proposed
formulation offers a flexible and versatile framework for the quantitative
modeling of flexible fibers deformation and rotation in shear flow, the
dynamics of actuated filaments and the propulsion of active swimmers.
Furthermore, a new contact model called Gears Model is proposed and
successfully tested. It avoids the use of numerical artifices such as repulsive
forces between adjacent beads, a source of numerical difficulties in the
temporal integration of previous Bead Models.Comment: 41 pages, 15 figure
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