267 research outputs found
Friends and Enemies in Athenian Politics
Copyright © The Classical Association 1996The Greeks divided their world into a number of contrasting categories which cut across and dissected each other: Greek and barbarian, slave and free, friend and enemy, insider and outsider, us and them. This essentially bipartite view of the world (although the dualism changed according to circumstance) affected the way Greek society worked, and the way that the Greeks thought about themselves. In this pair of papers, Professor Rhodes and I will be concerned only with one of these oppositions, friends and enemies
THE ALLEGED FAILURE OF ATHENS IN THE FOURTH CENTURY
The view that the successes of Macedon in the fourth century marked the failure, orthe end, of the Greek polis is increasingly being abandoned, and some scholars are abandoningalso the view that Athens was great and glorious in the fi fth century but degenerate in the fourth.However, the successes of Macedon meant for Athens the loss of that ultimate freedom whichit had aspired to and had often enjoyed between the early fi fth century and the late fourth, freedomnot merely from receiving orders from others but to give orders to others, and in this paperI explore the reasons for that change. Some scholars believe that fourth-century Athens was ledastray by “the ghost of empire;” others believe that the Athenians were unwilling to pay for a responsewhich could have defeated Philip; I argue that except in the years after Leuctra the ghostof empire did not have malign effects, and even with more expenditure Athens could not havedefeated Philip. There was nothing fundamentally wrong with Athens in the fourth century, butSparta’s success in the Hellespont in 387 and the resulting King’s Peace, the rule in Macedon ofPhilip II, who was too clever diplomatically and became too strong militarily for the Athenians,and Alexander’s succession in 336 and his success and survival in his campaigns, placed Athensin situations which it could not overcome
Dissolved organic nutrient uptake by riverine phytoplankton varies along a gradient of nutrient enrichment
The concentration of dissolved organic matter (DOM) in freshwaters is increasing in large areas of the world. In addition to carbon, DOM contains nitrogen and phosphorus and there is growing concern that these organic nutrients may be bioavailable and contribute to eutrophication. However, relatively few studies have assessed the potential for dissolved organic nitrogen (DON) or dissolved organic phosphorus (DOP) compounds to be bioavailable to natural river phytoplankton communities at different locations or times. Temporal and spatial variations in uptake, relative to environmental characteristics were examined at six riverine sites in two contrasting catchments in the UK. This study also examined how the uptake by riverine phytoplankton of four DON and four DOP compounds commonly found in rivers, varied with concentration. Total nitrogen (TN) and phosphorus (TP) concentrations, the proportion of inorganic nutrient species, and nutrient limitation varied temporally and spatially, as did the potential for DON and DOP uptake. All eight of the DOM compounds tested were bioavailable, but to different extents. Organic nutrient use depended on the concentration of the organic compound supplied, with simple compounds (urea and glucose-6-phosphate) supporting algal growth even at very low concentrations. DON use was negatively correlated with the TN and ammonia concentration and DOP use was negatively correlated with soluble reactive phosphorus (SRP) and dissolved organic carbon (DOC) concentration. The evidence indicates that DOM in rivers has been overlooked as a potential source of nutrients to phytoplankton and therefore as an agent of eutrophication
Computation of protein geometry and its applications: Packing and function prediction
This chapter discusses geometric models of biomolecules and geometric
constructs, including the union of ball model, the weigthed Voronoi diagram,
the weighted Delaunay triangulation, and the alpha shapes. These geometric
constructs enable fast and analytical computaton of shapes of biomoleculres
(including features such as voids and pockets) and metric properties (such as
area and volume). The algorithms of Delaunay triangulation, computation of
voids and pockets, as well volume/area computation are also described. In
addition, applications in packing analysis of protein structures and protein
function prediction are also discussed.Comment: 32 pages, 9 figure
Cosmological Evolution of Brane World Moduli
We study cosmological consequences of non-constant brane world moduli in five
dimensional brane world models with bulk scalars and two boundary branes. We
focus on the case where the brane tension is an exponential function of the
bulk scalar field, . In the limit , the model reduces to the two-brane model of Randall-Sundrum, whereas larger
values of allow for a less warped bulk geometry. Using the moduli
space approximation, we derive the four-dimensional low-energy effective action
from a supergravity-inspired five-dimensional theory. For arbitrary values of
, the resulting theory has the form of a bi-scalar-tensor theory. We
show that, in order to be consistent with local gravitational observations,
has to be small (less than ) and the separation of the branes
must be large. We study the cosmological evolution of the interbrane distance
and the bulk scalar field for different matter contents on each branes. Our
findings indicate that attractor solutions exist which drive the moduli fields
towards values consistent with observations. The efficiency of the attractor
mechanism crucially depends on the matter content on each branes. In the
five-dimensional description, the attractors correspond to the motion of the
negative tension brane towards a bulk singularity, which signals the eventual
breakdown of the four-dimensional description and the necessity of a better
understanding of the bulk singularity.Comment: 18 pages, 10 figures, typos and factor of 2 corrected, version to
appear in Physical Review
Scale-free memory model for multiagent reinforcement learning. Mean field approximation and rock-paper-scissors dynamics
A continuous time model for multiagent systems governed by reinforcement
learning with scale-free memory is developed. The agents are assumed to act
independently of one another in optimizing their choice of possible actions via
trial-and-error search. To gain awareness about the action value the agents
accumulate in their memory the rewards obtained from taking a specific action
at each moment of time. The contribution of the rewards in the past to the
agent current perception of action value is described by an integral operator
with a power-law kernel. Finally a fractional differential equation governing
the system dynamics is obtained. The agents are considered to interact with one
another implicitly via the reward of one agent depending on the choice of the
other agents. The pairwise interaction model is adopted to describe this
effect. As a specific example of systems with non-transitive interactions, a
two agent and three agent systems of the rock-paper-scissors type are analyzed
in detail, including the stability analysis and numerical simulation.
Scale-free memory is demonstrated to cause complex dynamics of the systems at
hand. In particular, it is shown that there can be simultaneously two modes of
the system instability undergoing subcritical and supercritical bifurcation,
with the latter one exhibiting anomalous oscillations with the amplitude and
period growing with time. Besides, the instability onset via this supercritical
mode may be regarded as "altruism self-organization". For the three agent
system the instability dynamics is found to be rather irregular and can be
composed of alternate fragments of oscillations different in their properties.Comment: 17 pages, 7 figur
Subcritical multiplicative chaos for regularized counting statistics from random matrix theory
For an N×N random unitary matrix U_N, we consider the random field defined by counting the number of eigenvalues of U_N in a mesoscopic arc of the unit circle, regularized at an N-dependent scale Ɛ_N>0. We prove that the renormalized exponential of this field converges as N → ∞ to a Gaussian multiplicative chaos measure in the whole subcritical phase. In addition, we show that the moments of the total mass converge to a Selberg-like integral and by taking a further limit as the size of the arc diverges, we establish part of the conjectures in [55]. By an analogous construction, we prove that the multiplicative chaos measure coming from the sine process has the same distribution, which strongly suggests that this limiting object should be universal. The proofs are based on the asymptotic analysis of certain Toeplitz or Fredholm determinants using the Borodin-Okounkov formula or a Riemann-Hilbert problem for integrable operators. Our approach to the L¹-phase is based on a generalization of the construction in Berestycki [5] to random fields which are only asymptotically Gaussian. In particular, our method could have applications to other random fields coming from either random matrix theory or a different context
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Executive function in Williams and Down syndromes
Williams (WS) and Down (DS) syndromes are characterised by roughly opposing ability profiles. Relative verbal strengths and visuospatial difficulties have been reported in those with WS, while expressive language difficulties have been observed in individuals with DS. Few investigations into the executive function (EF) skills of these groups have examined the effect of verbal/visuospatial task type on performance. Analogous verbal and visuospatial measures were administered to these populations within four EF domains: executive-loaded working memory (ELWM), inhibition, fluency and set-shifting. Performance in both groups was compared to that of typically developing (TD) children using regression techniques controlling for potentially influential cognitive/developmental factors. Individuals with WS showed the expected relative visuospatial difficulties, as indicated by poorer performance than TD individuals, on tests of ELWM and fluency. Individuals with DS displayed the expected relative verbal difficulty in the domain of set-shifting. In addition, each population showed pervasive deficits across modality in one domain; ELWM for individuals with DS, and inhibition for individuals with WS. Individuals with WS and DS showed EF difficulties in comparison to a TD group, but, their executive performance was affected by EF task type (verbal/visuospatial) and EF domain in different ways. While the findings indicated that EF in these populations is characterised by a range of specific strengths and weaknesses, it was also suggested that the relative verbal/visuospatial strengths associated with each population do not consistently manifest across EF domains. Lastly, syndrome specificity was indicated by the differences in groups’ performance patterns
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Using developmental trajectories to examine verbal and visuospatial short-term memory development in children and adolescents with Williams and Down syndromes
Williams (WS) and Down (DS) syndromes have been associated with specifically compromised short-term memory (STM) subsystems. Individuals with WS have shown impairments in visuospatial STM, while individuals with DS have often shown problems with the recall of verbal material. However, studies have not usually compared the development of STM skills in these domains, in these populations. The present study employed a cross sectional developmental trajectories approach, plotting verbal and visuospatial STM performance against more general cognitive and chronological development, to investigate how the domain-specific skills of individuals with WS and DS may change as development progresses, as well as whether the difference between STM skill domains increases, in either group, as development progresses. Typically developing children, of broadly similar cognitive ability to the clinical groups, were also included. Planned between- and within group comparisons were carried out. Individuals with WS and DS both showed the domain specific STM weaknesses in overall performance that were expected based on the respective cognitive profiles. However, skills in both groups developed, according to general cognitive development, at similar rates to those of the TD group. In addition, no significant developmental divergence between STM domains was observed in either clinical group according to mental age or chronological age, although the general pattern of findings indicated that the influence of the latter variable across STM domains, particularly in WS, might merit further investigation
US hegemony and the origins of Japanese nuclear power : the politics of consent
This paper deploys the Gramscian concepts of hegemony and consent in order to explore the process whereby nuclear power was brought to Japan. The core argument is that nuclear power was brought to Japan as a consequence of US hegemony. Rather than a simple manifestation of one state exerting material ‘power over' another, bringing nuclear power to Japan involved a series of compromises worked out within and between state and civil society in both Japan and the USA. Ideologies of nationalism, imperialism and modernity underpinned the process, coalescing in post-war debates about the future trajectory of Japanese society, Japan's Cold War alliance with the USA and the role of nuclear power in both. Consent to nuclear power was secured through the generation of a psychological state in the public mind combining the fear of nuclear attack and the hope of unlimited consumption in a nuclear-fuelled post-modern world
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