2,406 research outputs found
BPS Bounds for Worldvolume Branes
The worldvolume field equations of M-branes and D-branes are known to admit
p-brane soliton solutions. These solitons are shown to saturate a BPS-type
bound on their p-volume tensions, which are expressed in terms of central
charges that are expected to appear in the worldvolume supertranslation
algebra. The cases we consider include vortices, `BIons', instantons and dyons
(both abelian and non-abelian), and the string boundaries of M-2-branes in the
M-5-brane.Comment: Latex, 20 pages. References added, minor change
CRIME AND PUNISHMENT WITH HABIT FORMATION
Moral concepts affect crime supply. This idea is modelled assuming that illegal activities is habit forming. We introduce habits in a intertemporal general equilibrium framework to illegal activities and compare its outcomes with a model without habit formation. The findings are that habit (i) reduces the crime level; (ii) reduces the marginal effect of illegal activities return on crime; (iii) reduces the efficacy of punishment.
PUBLIC INVESTMENT IN BASIC EDUCATION AND ECONOMIC GROWTH
The main objective of this paper was to visualize the relation between government spending on basic education and the human capital accumulation process, observing the impacts of this spending on individual investments in higher education, and on economic growth. From the results obtained, we may reach the central conclusion that basic education affects agents' decisions over their lifetime, and that the significance of the relation between public spending on education and economic growth is altered by changes in the composition of government spending with regard to basic and higher education, and this relation may be insignificant when higher education is not promoted.
Monetary policy and country risk
This article develops an econometric model in order to study country risk behavior forsix emerging economies (Argentina, Mexico, Russia, Thailand, Korea and Indonesia),by expanding the Country Beta Risk Model of Harvey and Zhou (1993), Erb et. al.(1996a, 1996b) and Gangemi et. al. (2000). Toward this end, we have analyzed theimpact of macroeconomic variables, especially monetary policy, upon country risk,by way of a time varying parameter approach. The results indicate an inefficient andunstable effect of monetary policy upon country risk in periods of crisis. However, thiseffect is stable in other periods, and the Favero-Giavazzi effect is not verified for alleconomies, with an opposite effect being observed in many cases.
General Very Special Relativity is Finsler Geometry
We ask whether Cohen and Glashow's Very Special Relativity model for Lorentz
violation might be modified, perhaps by quantum corrections, possibly producing
a curved spacetime with a cosmological constant. We show that its symmetry
group ISIM(2) does admit a 2-parameter family of continuous deformations, but
none of these give rise to non-commutative translations analogous to those of
the de Sitter deformation of the Poincar\'e group: spacetime remains flat. Only
a 1-parameter family DISIM_b(2) of deformations of SIM(2) is physically
acceptable. Since this could arise through quantum corrections, its
implications for tests of Lorentz violations via the Cohen-Glashow proposal
should be taken into account. The Lorentz-violating point particle action
invariant under DISIM_b(2) is of Finsler type, for which the line element is
homogeneous of degree 1 in displacements, but anisotropic. We derive
DISIM_b(2)-invariant wave equations for particles of spins 0, 1/2 and 1. The
experimental bound, , raises the question ``Why is the
dimensionless constant so small in Very Special Relativity?''Comment: 4 pages, minor corrections, references adde
The generic mapping tools version 6
The Generic Mapping Tools (GMT) software is ubiquitous in the Earth and ocean sciences. As a cross-platform tool producing high-quality maps and figures, it is used by tens of thousands of scientists around the world. The basic syntax of GMT scripts has evolved very slowly since the 1990s, despite the fact that GMT is generally perceived to have a steep learning curve with many pitfalls for beginners and experienced users alike. Reducing these pitfalls means changing the interface, which would break compatibility with thousands of existing scripts. With the latest GMT version 6, we solve this conundrum by introducing a new "modern mode" to complement the interface used in previous versions, which GMT 6 now calls "classic mode." GMT 6 defaults to classic mode and thus is a recommended upgrade for all GMT 5 users. Nonetheless, new users should take advantage of modern mode to make shorter scripts, quickly access commonly used global data sets, and take full advantage of the new tools to draw subplots, place insets, and create animations.Funding Agency
National Science Foundation (NSF)
Appeared in article as
U.S. National Science Foundation
MSU Geological Sciences Endowmentinfo:eu-repo/semantics/publishedVersio
Experimental characterization of a 6.7 GHz coaxial Bragg reflector
A coaxial line periodically loaded by circular disks on the inner conductor is designed and constructed to act as Bragg reflector in the 4.0-9.5 GHz frequency range. This is achieved by placing 10 disks (0.35 cm thick and 6.22 cm in diameter) equally spaced by the periodic distance of 1.8 cm on a coaxial waveguide with inner and outer diameters of 6.90 and 4.22 cm. Experiments on a periodic structure made from stainless steel demonstrate a band gap of 5.6 GHz centered at the 6.7 GHz design frequency in close agreement with 3D microwave computer simulations. © 2007 American Institute of Physics
The Unbearable Lightness of Academic Fraud: Portuguese Higher Education Students’ Perceptions
The perception that academic fraud is widespread in higher education affects the credibility
of higher education schools, giving rise to doubts concerning the quality of learning and the students’
preparation for their professional life. Academic misconduct is presently a common research area.
However, higher education schools still seem unable to contain academic fraud, given its prevalence
and scope. Therefore, understanding students’ perceptions and attitudes remains critical for schools to
define effective policies in promoting and defending academic integrity. Towards that aim, the results
from a set of focus groups of students from a higher education school are presented. Students do not
link academic fraud with unethical professional behaviour, propose more sanctions for those who
commit academic fraud, and consider that certain evaluation methods favour unethical behaviour.info:eu-repo/semantics/publishedVersio
Optimization of the Kinematics of a Flapping Wing MAV in Hover for Enhanced Performance
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106431/1/AIAA2013-1646.pd
MODELO INTERTEMPORAL DA CONTA CORRENTE: EVIDÊNCIAS PARA O BRASIL
The paper uses the procedure developed first by Campbell (1987) to test, for the Brazilian economy, the proposition that the balance of the current account is negatively related to the present value of the future changes of the GDP net of the investment and consumption of the government. Within the framework of intertemporal choice transitory shocks should affect the current account since the agents use credit or give loans in the international capital market to smooth the consumption pattern. On the contrary, when the shocks are permanent the agents adjust to a new consumption level and the effect on the current account is small. This means that the model should adjusts fairly well in countries with short run fluctuations. The empirical results of this work suggest that the present value of the future GDP path is able to explain the behavior of the quarter and annual Brazilian current account giving support to the model of intertemporal choice optimization.
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