12,499 research outputs found
The Methodology of Political Theory
This article examines the methodology of a core branch of contemporary political theory or philosophy: “analytic” political theory. After distinguishing political theory from related fields, such as political science, moral philosophy, and legal theory, the article discusses the analysis of political concepts. It then turns to the notions of principles and theories, as distinct from concepts, and reviews the methods of assessing such principles and theories, for the purpose of justifying or criticizing them. Finally, it looks at a recent debate on how abstract and idealized political theory should be, and assesses the significance of disagreement in political theory. The discussion is carried out from an angle inspired by the philosophy of science
What Normative Facts Should Political Theory Be About? Philosophy of Science meets Political Liberalism
Just as different sciences deal with different facts—say, physics versus biology—so we may
ask a similar question about normative theories. Is normative political theory concerned
with the same normative facts as moral theory or different ones? By developing an analogy
with the sciences, we argue that the normative facts of political theory belong to a higher—
more coarse-grained—level than those of moral theory. The latter are multiply realizable by
the former: competing facts at the moral level can underpin the same facts at the political
one. Consequently, some questions that moral theories answer are indeterminate at the
political level. This proposal offers a novel interpretation of John Rawls’s idea that, in public
reasoning, we should abstract away from comprehensive moral doctrines. We contrast our
distinction between facts at different levels with the distinction between admissible and
inadmissible evidence and discuss some implications for the practice of political theory
Electroweak corrections in the 2HDM for neutral scalar Higgs-boson production through gluon fusion
We have computed the two-loop, electroweak corrections to the production of a
light and a heavy neutral, scalar Higgs-boson through the important gluon
fusion process in the Two-Higgs-Doublet Model. We provide our results in
various renormalization schemes for different scenarios and benchmark points,
which will be valuable for experimental studies at the LHC. We describe the
technicalities of our two-loop calculation and augment it by a phenomenological
discussion. Our results are also applicable to the gluonic neutral, scalar
Higgs-boson decays.Comment: 36 pages, 11 figures, 8 tables, v2: version accepted for publication
in the journa
Ultrasensitivity and sharp threshold theorems for multisite systems
We study the ultrasensitivity of multisite binding processes where ligand
molecules can bind to several binding sites, considering more particularly
recent models involving complex chemical reactions in phosphorylation systems
such as allosteric phosphorylation processes, or substrate-catalyst chain
reactions and nucleosome mediated cooperativity. New statistics based formulas
for the Hill coefficient and the effective Hill coefficient are provided and
necessary conditions for a system to be ultrasensitive are exhibited. We then
assume that the binding process is described by a density dependent birth and
death process. We provide precise large deviation results for the steady state
distribution of the process, and show that switch-like ultrasensitive responses
are strongly related to the multi-stability of the associated dynamical system.
Ultrasensitivity occurs if and only if the entropy of the dynamical system has
more than one global minimum for some critical ligand concentration. In this
case, the Hill coefficient is proportional to the number of binding sites, and
the systems is highly ultrasensitive. We also discuss the interpretation of an
extension of the effective Hill coefficient for which we
recommend the computation of a broad range of values of instead of just the
standard one corresponding to the 10% to 90% variation in the dose-response. It
is shown that this single choice can sometimes mislead the conclusion by not
detecting ultrasensitivity. This new approach allows a better understanding of
multisite ultrasensitive systems and provides new tools for the design of such
systems
Timing is everything: the impact of wakeup schedule distribution on asynchronous power save protocols
Asynchronous power save protocols have been proposed for use in ad hoc networks. In many protocols, nodes independently follow a common periodic wakeup schedule, each with some unknown offset relative to its neighbors.
The schedule is defined to ensure deterministic intervals of overlap between nodes, regardless of the distribution of the nodes' wakeup schedules. This paper studies the sensitivity of a simple asynchronous power save
protocol to the actual distribution of the nodes' wakeup schedules. In practical terms: For given topology and traffic load, are there particularly "good" or "bad" distributions?
We define a simplified model of network operation that allows us to study this question in simulation. The results show that the performance variation has a narrow probability distribution, but with long tails. The variation is shown to derive largely from timing dependencies rather than overall capacity of the system. The result suggests the feasibility of manipulating the wakeup schedule distribution to improve performance. Although the best wakeup distributions often mitigate the performance penalty imposed by the power save
protocol, their relative rarity implies that randomized strategies will not be sufficient to obtain maximum advantage
The impact of wakeup schedule distribution in synchronous power save protocols on the performance of multihop wireless networks
By definition, the operation of an asynchronous power save protocol permits an arbitrary distribution of nodes' wakeup schedules. This wakeup schedule distribution creates an uncoordinated pattern of times at which nodes will attempt to transmit. Intuitively, we would expect that some patterns will be more (or less) favorable than others for a given traffic pattern.
We investigate the impact of this wakeup pattern on network capacity and present simulation data showing that the capacity associated with the best wakeup patterns is significantly larger than that of the worst. This result not only gives insight to the behavior of such protocols, but also acts as a feasibility study showing the potential benefit of mechanisms by which nodes adapt their wakeup schedules to obtain improved performance
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