Tax and Education Policy in a Heterogeneous Agent Economy: What Levels of Redistribution Maximize Growth and Efficiency?

INCOME REDISTRIBUTION; HETEROGENOUS AGENTS; INEQUALITY; GROWTH; REDISTRIBUTION; EDUCATION FINANCE.

Using privileged information to manipulate markets: insiders, gurus, and credibility

Access to private information is shown to generate both the incentives and the ability to manipulate asset markets through strategically distorted announcements. The fact that privileged information is noisy interferes with the public's attempts to learn whether such announcements are honest; it allows opportunistic individuals to manipulate prices repeatedly, without ever being fully found out. This leads us to extend Sobel's [1985] model of strategic communication to the case of noisy private signals. Our results show that when truthfulness is not easily verifiable, restrictions on trading by insiders may be needed to preserve the integrity of information embodied in prices

Social Mobility and the Demand for Redistribution: The POUM Hypothesis

Even people with income below average will not support high rates of redistribution, because of the prospect of upward mobility: they take into account the fact the they, or their children, may move up in the income distribution, and therefore be hurt by high tax rates. This "intuitive" hypothesis is commonly advanced as part of the explanation for why democracies, where a relatively poor majority holds the political power, do not engage in large-scale expropriation and redistribution. But does it make sense, or does it require that some of the poor overemphasize the prospects of good outcomes relative to bad ones, due either to irrationally optimistic expectations or to a form of risk-loving?INCOME DISTRIBUTION ; POLITICAL ECONOMY ; TAXATION ; SOCIAL MOBILITY

Unequal Societies.

This paper aims to explain the significant variations in the social contracts which can be observed across nations. It shows in particular how countries with similar technologies and preferences, as well as equally democratic political systems, can sustain very different avrage and marginal tax rates.SOCIAL JUSTICE;INCOME;POLITICAL ECONOMY;TAXATION;WELFARE ECONOMICS;WELFARE STATE

Meritocracy, Redistribution, and the Size of the Pie.

This paper examines how ambiguous notions such as "meritocracy" , "equality of opportunity" and "equality of outcomes" can be given a formal content and related to more standard economic concepts such as social mobility, income inequality, and efficiency.INCOME;EDUCATION;DISTRIBUTION

Signatures of Primordial Energy Injection from Axion Strings

Axion strings are horizon-size topological defects that may be produced in the early Universe. Ultra-light axion-like particles may form strings that persist to temperatures below that of big bang nucleosynthesis. Such strings have been considered previously as sources of gravitational waves and cosmic microwave background (CMB) polarization rotation. In this work we show, through analytic arguments and dedicated adaptive mesh refinement cosmological simulations, that axion strings deposit a sub-dominant fraction of their energy into high-energy Standard Model (SM) final states, for example, by the direct production of heavy radial modes that subsequently decay to SM particles. This high-energy SM radiation is absorbed by the primordial plasma, leading to novel signatures in precision big bang nucleosynthesis, the CMB power spectrum, and gamma-ray surveys. In particular, we show that CMB power spectrum data constrains axion strings with decay constants $f_a \lesssim 10^{12}$ GeV, up to model dependence on the ultraviolet completion, for axion masses $m_a \lesssim 10^{-29}$ eV; future CMB surveys could find striking evidence of axion strings with lower decay constants.Comment: 30 pages, 20 figures, Supplementary Animations at https://goo.by/qHk9d, Video Abstract at https://youtu.be/Ae4AR46qKn

Detecting axion dark matter beyond the magnetoquasistatic approximation

A number of proposals have been put forward for detecting axion dark matter (DM) with grand unification scale decay constants that rely on the conversion of coherent DM axions to oscillating magnetic fields in the presence of static, laboratory magnetic fields. Crucially, such experiments \unicode{x2013} including ABRACADABRA \unicode{x2013} have to-date worked in the limit that the axion Compton wavelength is larger than the size of the experiment, which allows one to take a magnetoquasistatic (MQS) approach to modeling the axion signal. We use finite element methods to solve the coupled axion-electromagnetism equations of motion without assuming the MQS approximation. We show that the MQS approximation becomes a poor approximation at frequencies two orders of magnitude lower than the naive MQS limit. Radiation losses diminish the quality factor of an otherwise high-$Q$ resonant readout circuit, though this may be mitigated through shielding and minimizing lossy materials. Additionally, self-resonances associated with the detector geometry change the reactive properties of the pickup system, leading to two generic features beyond MQS: there are frequencies that require an inductive rather than capacitive tuning to maintain resonance, and the detector itself becomes a multi-pole resonator at high frequencies. Accounting for these features, competitive sensitivity to the axion-photon coupling may be extended well beyond the naive MQS limit.Comment: 6+5 pages, 3+9 figure

Color Doppler imaging of the superior ophthalmic vein in patients with Graves' orbitopathy before and after treatment of congestive disease

OBJECTIVE: To compare superior ophthalmic vein blood flow parameters measured with color Doppler imaging in patients with congestive Graves' orbitopathy before and after treatment and in normal controls. METHODS: Twenty-two orbits from 12 patients with Graves' orbitopathy in the congestive stage and 32 orbits from 16 normal controls underwent color Doppler imaging studies. Color Doppler imaging was repeated after treatment in the group of patients with Graves' orbitopathy, which included orbital decompression in 16 orbits and corticosteroids in six orbits. The findings for each group were compared. RESULTS: In the group of orbits with congestive disease, superior ophthalmic vein flow was detected in 17 orbits (anteroposteriorally in 13 and in the opposite direction in four) and was undetectable in five. After treatment, superior ophthalmic vein flow was detected and anteroposterior in 21 and undetected in one orbit. In normals, superior ophthalmic vein flow was detected anteroposterior in 29 orbits and undetectable in three orbits, indicating a significant difference between groups. There was also a significant difference between controls and congestive Graves' orbits and between congestive orbits before and after treatment, but not between controls and patients after treatment. A comparison of superior ophthalmic vein flow parameters revealed a significant difference between the groups. The superior ophthalmic vein flow was significantly reduced in the congestive stage compared with the flow parameters following treatment and in the untreated controls. CONCLUSIONS: Superior ophthalmic vein flow was significantly reduced in the orbits affected with congestive Graves' orbitopathy and returned to normal following treatment. Congestion appears to be a contributing pathogenic factor in the active inflammatory stage of Graves' orbitopathy.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Higher Algebraic Structures and Quantization

We derive (quasi-)quantum groups in 2+1 dimensional topological field theory directly from the classical action and the path integral. Detailed computations are carried out for the Chern-Simons theory with finite gauge group. The principles behind our computations are presumably more general. We extend the classical action in a d+1 dimensional topological theory to manifolds of dimension less than d+1. We then ``construct'' a generalized path integral which in d+1 dimensions reduces to the standard one and in d dimensions reproduces the quantum Hilbert space. In a 2+1 dimensional topological theory the path integral over the circle is the category of representations of a quasi-quantum group. In this paper we only consider finite theories, in which the generalized path integral reduces to a finite sum. New ideas are needed to extend beyond the finite theories treated here.Comment: 62 pages + 16 figures (revised version). In this revision we make some small corrections and clarification