5,611 research outputs found
U.S. Federal Reserve Monetary Policy and the Fisrt Crisis of Securitization: Mexico and Latin America, 1994-1995
The decisions of the Federal Reserve of United States (Fed)determinig interest rates have played a critical role in capital inflows/outflows toward Mexico and Latin America. The causal relationship that exists between the Fed and emergin markets is quite close; a clear example of this is the first crisis of securitization on the global level, which originated in Mexico in 1994. The monetary policy of the Fed supported the expansion of U.S. investment banks and some institutional investors, thus creating not only an enormous bubble in Mexico and other local financial markets in Latin America through the expansion of portfolio investment, but also succesive financial crises during the 1990s when those financial capital flows reversed themseleves
Cosmological scenarios from multiquintessence
In this work we derive and analyse cosmological scenarios coming from
multi-component scalar field models. We consider a direct sum of a sine-Gordon
with a Z2 model, and also a combination of those with a BNRT model. Moreover,
we work with a modified version of the BNRT model, which breaks the Z2 x Z2
symmetry of the original BNRT potential, coupled with the sine-Gordon and with
the standard Z2 models. We show that our approach can be straightforwardly
elevated to fields. All the computations are made analytically and some
parameters restriction is put forward in order to get in touch with complete
and realistic cosmological scenarios
High-magnetic field lattice length changes in URu2Si2
We report high magnetic field (up to 45 T) c-axis thermal expansion and
magnetostriction experiments on URu2Si2 single crystals. The sample length
change associated with the transition to the hidden order phase becomes
increasingly discontinous as the magnetic field is raised above 25 T. The
re-entrant ordered phase III is clearly observed in both the thermal expansion
and magnetostriction above 36 T, in good agreement with previous results. The
sample length is also discontinuous at the boundaries of this phase, mainly at
the upper boundary. A change in the sign of the coefficient of
thermal-expansion is observed at the metamagnetic transition (B_M = 38 T) which
is likely related to the existence of a quantum critical end point.Comment: 5 pages, 4 figures, to be published in PR
Resistivity study of the pseudogap phase for (Hg,Re) - 1223 superconductors
The pseudogap phase above the critical temperature of high
superconductors (HTSC) presents different energy scales and it is currently a
matter of intense study. The complexity of the HTSC normal state requires very
accurate measurements with the purpose of distinguishing different types of
phenomena. Here we have performed systematically studies through electrical
resistivity () measurements by several different current densities in
order to obtain an optimal current for each sample. This approach allows to
determine reliable values of the pseudogap temperature , the layer
coupling temperature between the superconductor layers , the
fluctuation temperature and the critical temperature as
function of the doping . The interpretation of these different temperature
scales allows to characterize possible scenarios for the (Hg,Re) - 1223 normal
state. This method, described in detail here, and used to derive the
(Hg,Re)-1223 phase diagram is general and can be applied to any HTSC.Comment: 31 pages, 12 figures, Latex; 25 pages, LaTeX; 11 figures; rewrited
section II and III; added 18 reference; rewrited title, added discussion
sectio
A versatile and compact capacitive dilatometer
We describe the design, construction, calibration, and operation of a
relatively simple differential capacitive dilatometer suitable for measurements
of thermal expansion and magnetostriction from 300 K to below 1 K with a
low-temperature resolution of about 0.05 angstroms. The design is characterized
by an open architecture permitting measurements on small samples with a variety
of shapes. Dilatometers of this design have operated successfully with a
commercial physical property measurement system, with several types of
cryogenic refrigeration systems, in vacuum, in helium exchange gas, and while
immersed in liquid helium (magnetostriction only) to temperatures of 30 mK and
in magnetic fields to 45 T.Comment: 8 pages, incorporating 6 figures, submitted to Rev. Sci. Instru
Magnetic Field-Induced Condensation of Triplons in Han Purple Pigment BaCuSiO
Besides being an ancient pigment, BaCuSiO is a quasi-2D magnetic
insulator with a gapped spin dimer ground state. The application of strong
magnetic fields closes this gap creating a gas of bosonic spin triplet
excitations called triplons. The topology of the spin lattice makes
BaCuSiO an ideal candidate for studying the Bose-Einstein condensation
of triplons as a function of the external magnetic field, which acts as a
chemical potential. In agreement with quantum Monte Carlo numerical
simulations, we observe a distinct lambda-anomaly in the specific heat together
with a maximum in the magnetic susceptibility upon cooling down to liquid
Helium temperatures.Comment: published on August 20, 200
Matrix Models of Noncommutative (2d+1) Lattice Gauge Theories
We investigate the problem of mapping, through the Morita equivalence, odd
dimensional noncommutative lattice gauge theories onto suitable matrix models.
We specialize our analysis to noncommutative three dimensional QED (NCQED) and
scalar QED (NCSQED), for which we explicitly build the corresponding Matrix
Model.Comment: 13 pages, LaTeX, no Figure
Selectable Nanopattern Arrays for Nanolithographic Imprint and Etch-Mask Applications
A parallel nanolithographic patterning method is presented that can be used to obtain arrays of multifunctional nanoparticles. These patterns can simply be converted into a variety of secondary nanopatterns that are useful for nanolithographic imprint, plasmonic, and etch-mask applications
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