10,226 research outputs found
Half eigenvalues and the Fucik spectrum of multi-point, boundary value problems
We consider the nonlinear boundary value problem consisting of the equation
\tag{1} -u" = f(u) + h, \quad \text{a.e. on ,} where ,
together with the multi-point, Dirichlet-type boundary conditions \tag{2} u(\pm
1) = \sum^{m^\pm}_{i=1}\alpha^\pm_i u(\eta^\pm_i) where are
integers, ,
, and we suppose that We also suppose that is continuous, and We allow --- such a
nonlinearity is {\em jumping}.
Related to (1) is the equation \tag{3} -u" = \lambda(a u^+ - b u^-), \quad
\text{on ,} where , and for . The problem (2)-(3) is `positively-homogeneous'
and jumping. Regarding as fixed, values of for
which (2)-(3) has a non-trivial solution will be called {\em
half-eigenvalues}, while the corresponding solutions will be called {\em
half-eigenfunctions}.
We show that a sequence of half-eigenvalues exists, the corresponding
half-eigenfunctions having specified nodal properties, and we obtain certain
spectral and degree theoretic properties of the set of half-eigenvalues. These
properties lead to solvability and non-solvability results for the problem
(1)-(2). The set of half-eigenvalues is closely related to the `Fucik spectrum'
of the problem, which we briefly describe. Equivalent solvability and
non-solvability results for (1)-(2) are obtained from either the
half-eigenvalue or the Fucik spectrum approach
Culture and Development: An Analytical Framework
This paper develops a framework which analyzes how a population's culture affects the decisions of rational profit maximizing firms, while simultaneously exploring how the actions of these firms in turn affect the population's culture.By endogenizing culture as well as the more usual economic variables, it shows how an economically valuablebehavioural trait can be sustained as part of a competitive equilibrium.It is shown that, for given primitives, an economy can be in either a 'good' steady state, in which the valuable cultural trait is present, or a welfare dominated 'bad' one in which the valuable cultural trait disappears.Starting from the 'good' steady state and implementing productivity improvements raises welfare, but if changes are too rapid this steady state will not be reached from the old one.Instead, the unique trajectory is to the bad steady state where welfare is reduced.culture;development;inequality;technological change
Trust, Social Capital and Economic Development
Many argue that elements of a society s norms, culture or social capital are central to understanding its development.However, these notions have been difficult to capture in economic models.Here we argue that trustworthiness is the economically relevant component of a society s culture and hence comprises its social capital.Individuals are trustworthy when they perform actions they have promised, even if these do not maximize their payoffs.The usual focus on incentive structures in motivating behaviour plays no role here.Instead, we emphasize more deep-seated modes of behaviour and consider that trustworthy agents are socialized to act as they do.To model this socialization, we borrow from a relatively new process of preference evolution pioneered by Bisin and Verdier (2001).The model developed endogenously accounts for social capital and explores its role in the process of economic development.It captures in a simple, formal way the interaction between social capital and the economy s productive process.The results obtained caution against rapid reform, provide an explanation for why late developing countries cannot easily transplant the modes of production that have proved useful in the West, and suggest an explanation for the pattern of reform experiences in ex-communist countries.technological change;public finance;economic development
Characterization of the size and position of electron-hole puddles at a graphene p-n junction
The effect of an electron-hole puddle on the electrical transport when
governed by snake states in a bipolar graphene structure is investigated. Using
numerical simulations we show that information on the size and position of the
electron-hole puddle can be obtained using the dependence of the conductance on
magnetic field and electron density of the gated region. The presence of the
scatterer disrupts snake state transport which alters the conduction pattern.
We obtain a simple analytical formula that connects the position of the
electron-hole puddle with features observed in the conductance. Size of the
electron-hole puddle is estimated from the magnetic field and gate potential
that maximizes the effect of the puddle on the electrical transport.Comment: This is an author-created, un-copyedited version of an article
published in Nanotechnology. IOP Publishing Ltd is not responsible for any
errors or omissions in this version of the manuscript or any version derived
from it. The Version of Record is available online at
doi:10.1088/0957-4484/27/10/10520
Gender Wage Differentials in a Competitive Labor Market: The Household Interaction Effect
We present a theoretical explanation of the gender wage gap which turns on the interaction between men and women in households.In equilibria where men are over-represented in full-time work, we show that firms rationally choose to hire women only at strictly lower wages than men.The model developed predicts a gap even controlling for education, occupation and industry of workers and does so in a competitive labor market where there exist no inherent gender differences. We test our theory using CPS data over the period 1979-98 and find it is strongly supported by the data.gender discrimination;household models;wage gap
The relationship between noise and annoyance around Orly
The extent to which annoyance estimated by an isopsophic index is a good forecaster for annoyance perceived near airport approaches was investigated. An index of sensed annoyance is constructed, and the relationship between the annoyance index and the isopsophic index is studied
Co-movement, Capital and Contracts: 'Normal' Cycles Through Creative Destruction
We develop a unified theory of endogenous business cycles in which expansions are neoclassical growth periods driven by productivity improvements and capital accumulation, while downturns are the result of Keynesian contractions in aggregate demand below potential output. Recessions allow skilled labor to be reallocated to growth promoting activities which fuel subsequent expansions. However, rigidities in production and contractual limitations, inherent to the process of creative destruction, leave capital severely underutilized. A key feature of our equilibrium is the endogenous emergence of long term supply contracts between capitalist owners and producers.Long-term contracting;investment irreversibility;putty-clay technology;asset- specificity;Endogenous cycles and growth
A Definition of Metastability for Markov Processes with Detailed Balance
A definition of metastable states applicable to arbitrary finite state Markov
processes satisfying detailed balance is discussed. In particular, we identify
a crucial condition that distinguishes genuine metastable states from other
types of slowly decaying modes and which leads to properties similar to those
postulated in the restricted ensemble approach \cite{pen71}. The intuitive
physical meaning of this condition is simply that the total equilibrium
probability of finding the system in the metastable state is negligible. As a
concrete application of our formalism we present preliminary results on a 2D
kinetic Ising model.Comment: 5 pp. 1 Figure, presented in News, Expectations and Trends in
Statistical Physics-3rd International Conference, 13-18 August 2005,
Kolymbari Cret
870 micron Imaging of a Transitional Disk in Upper Scorpius: Holdover from the Era of Giant Planet Formation?
We present 880 micron images of the transition disk around the star [PZ99]
J160421.7-213028, a solar-mass star in the nearby Upper Scorpius association.
With a resolution down to 0.34 arcsec, we resolve the inner hole in this disk,
and via model fitting to the visibilities and spectral energy distribution we
determine both the structure of the outer region and the presence of sparse
dust within the cavity. The disk contains about 0.1 Jupiter masses of
mm-emitting grains, with an inner disk edge of about 70 AU. The inner cavity
contains a small amount of dust with a depleted surface density in a region
extending from about 20-70 AU. Taking into account prior observations
indicating little to no stellar accretion, the lack of a binary companion, and
the presence of dust near 0.1 AU, we determine that the most likely mechanism
for the formation of this inner hole is the presence of one or more giant
planets.Comment: 12 pages, 7 figures. To appear in the Astrophysical Journa
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