749 research outputs found
Financial Integration, Financial Deepness and Global Imbalances
Large and persistent global financial imbalances need not be the harbinger of a world financial crash. Instead, we show that these imbalances can be the outcome of financial integration when countries differ in financial markets deepness. In particular, countries with more advanced financial markets accumulate foreign liabilities in a gradual, long-lasting process. Differences in financial deepness also affect the composition of foreign portfolios: countries with negative net foreign asset positions maintain positive net holdings of non-diversifiable equity and FDI. Abstracting from the potential impact of globalization on financial development, liberalization leads to sizable welfare gains for the more financially-developed countries and losses for the others. Three empirical observations motivate our analysis: (1)financial deepness varies widely even amongst industrial countries, with the United States ranking at the top; (2) the secular decline in the U.S. net foreign asset position started in the early 1980s, together with a gradual process of international capital markets liberalization; (3) net exports and current account balances are negatively correlated with indicators of financial development.
On the Welfare Implications of Financial Globalization without Financial Development
It is widely argued that countries can reap large gains from liberalizing their capital accounts if financial globalization is accompanied by the development of domestic institutions and financial markets. However, if liberalization does not lead to financial development, globalization can result in adverse effects on social welfare and the distribution of wealth. We use a multi-country model with non-insurable idiosyncratic risk to show that, if countries differ in the degree of asset market incompleteness, financial globalization hurts the poor in countries with less developed financial markets. This is because in these countries liberalization leads to an increase in the cost of borrowing, which is harmful for those heavily leveraged, i.e. the poor. Quantitative analysis shows that the welfare effects are sizable and may justify policy intervention.
Orientational transitions in a nematic confined by competing surfaces
The effect of confinement on the orientational structure of a nematic liquid
crystal model has been investigated by using a version of density-functional
theory (DFT). We have focused on the case of a nematic confined by opposing
flat surfaces, in slab geometry (slit pore), which favor planar molecular
alignment (parallel to the surface) and homeotropic alignment (perpendicular to
the surface), respectively. The spatial dependence of the tilt angle of the
director with respect to the surface normal has been studied, as well as the
tensorial order parameter describing the molecular order around the director.
For a pore of given width, we find that, for weak surface fields, the alignment
of the nematic director is perpendicular to the surface in a region next to the
surface favoring homeotropic alignment, and parallel along the rest of the
pore, with a interface separating these regions (S phase). For strong surface
fields, the director is distorted uniformly, the tilt angle exhibiting a linear
dependence with the distance normal to the surface (L phase). Our calculations
reveal the existence of a first-order transition between the two director
configurations, which is driven by changes in the surface field strength, and
also by changes in the pore width. In the latter case the transition occurs,
for a given surface field, between the S phase for narrow pores and the L phase
for wider pores. A link between the L-S transition and the anchoring transition
observed for the semi-infinite case is proposed. We also provide calculations
with a phenomenological approach that yields the same main result that DFT in
the scale length where this is valid.Comment: submitted to PR
Breakdown of the mean-field approximation in a wealth distribution model
One of the key socioeconomic phenomena to explain is the distribution of
wealth. Bouchaud and M\'ezard have proposed an interesting model of economy
[Bouchaud and M\'ezard (2000)] based on trade and investments of agents. In the
mean-field approximation, the model produces a stationary wealth distribution
with a power-law tail. In this paper we examine characteristic time scales of
the model and show that for any finite number of agents, the validity of the
mean-field result is time-limited and the model in fact has no stationary
wealth distribution. Further analysis suggests that for heterogeneous agents,
the limitations are even stronger. We conclude with general implications of the
presented results.Comment: 11 pages, 3 figure
An ontology-based framework for describing discoverable data services
Data-services are applications in charge of retrieving certain data when they are called. They are found in different communities such as the Internet Of Things, Cloud Computing, Big Data, etc. So, there is a real need to discover how can an application that requires some data automatically find a data-service which is providing it. To our knowledge, the problem of automatically discovering these data-services is still open. To make a step forward in this direction, we propose an ontology-based framework to address this problem. In our framework, input and output values of the request are mapped into concepts of the domain ontology. Then, data-services specify how to obtain the output from the input by stating the relationship between the mapped concepts of the ontology.Peer ReviewedPostprint (author's final draft
Raman–Mo¨ssbauer–XRD studies of selected samples from ‘‘Los Azulejos” outcrop: A possible analogue for assessing the alteration processes on Mars
The outcrop of ‘‘Los Azulejos” is visible at the interior of the Can˜adas Caldera in Tenerife Island (Spain). It exhibits a great variety of
alteration processes that could be considered as terrestrial analogue for several geological processes on Mars. This outcrop is particularly
interesting due to the content of clays, zeolite, iron oxides, and sulfates corresponding to a hydrothermal alteration catalogued as ‘‘Azulejos”
type alteration. A detailed analysis by portable and laboratory Raman systems as well as other different techniques such as X-ray
diffraction (XRD) and Mo¨ssbauer spectroscopy has been carried out (using twin-instruments from Martian lander missions: Mo¨ssbauer
spectrometer MIMOS-II from the NASA-MER mission of 2001 and the XRD diffractometer from the NASA-MSL Curiosity mission of
2012). The mineral identification presents the following mineral species: magnetite, goethite, hematite, anatase, rutile, quartz, gregoryite,
sulfate (thenardite and hexahydrite), diopside, feldspar, analcime, kaolinite and muscovite. Moreover, the in-situ Raman and Micro-
Raman measurements have been performed in order to compare the capabilities of the portable system specially focused for the next
ESA Exo-Mars mission. The mineral detection confirms the sub-aerial alteration on the surface and the hydrothermal processes by
the volcanic fluid circulations in the fresh part. Therefore, the secondary more abundant mineralization acts as the color agent of the
rocks. Thus, the zeolite–illite group is the responsible for the bluish coloration, as well as the feldspars and carbonates for the whitish
and the iron oxide for the redish parts. The XRD system was capable to detect a minor proportion of pyroxene, which is not visible by
Raman and Mo¨ssbauer spectroscopy due to the ‘‘Azulejos” alteration of the parent material on the outcrop. On the other hand, Mo¨ ssbauer
spectroscopy was capable of detecting different types of iron-oxides (Fe3+/2+-oxide phases). These analyses emphasize the strength
of the different techniques and the working synergy of the three different techniques together for planetary space missions
Raman-Mössbauer-XRD studies of selected samples from “Los Azulejos” outcrop: A possible analogue for assessing the alteration processes on Mars
The outcrop of “Los Azulejos” is visible at the interior of the Cañadas Caldera in Tenerife Island (Spain). It exhibits a great variety of alteration processes that could be considered as terrestrial analogue for several geological processes on Mars. This outcrop is particularly interesting due to the content of clays, zeolite, iron oxides, and sulfates corresponding to a hydrothermal alteration catalogued as “Azulejos” type alteration. A detailed analysis by portable and laboratory Raman systems as well as other different techniques such as X ray diffraction (XRD) and Mössbauer spectroscopy has been carried out (using twin-instruments from Martian lander missions: Mössbauer spectrometer MIMOS-II from the NASA-MER mission of 2001 and the XRD diffractometer from the NASA-MSL Curiosity mission of 2012). The mineral identification presents the following mineral species: magnetite, goethite, hematite, anatase, rutile, quartz, gregoryite, sulphate (thenardite and hexahydrite), diopside, feldspar, analcime, kaolinite and muscovite. Moreover, the in-situ Raman and Micro-Raman measurements have been performed in order to compare the capabilities of the portable system specially focused for the next ESA Exo-Mars mission. The mineral detection confirms the sub-aerial alteration on the surface and the hydrothermal processes by the volcanic fluid circulations in the fresh part. Therefore, the secondary more abundant mineralization acts as the color agent of the rocks. Thus, the zeolite-illite group is the responsible for the bluish coloration, as well as the feldspars and carbonates for the whitish and the iron oxide for the redish parts. The XRD system was capable to detect a minor proportion of pyroxene, which is not visible by Raman and Mössbauer spectroscopy due to the “Azulejos” alteration of the parent material on the outcrop. On the other hand, Mössbauer spectroscopy was capable of detecting different types of iron-oxides (Fe3+/2+-oxide phases). These analyses emphasize the strength of the different techniques and the working synergy of the three different techniques together for planetary space missions.The work was supported by the MICINN with the Project AYA-2008-04529.Peer reviewe
Association of MC1R Variants and host phenotypes with melanoma risk in CDKN2A mutation carriers: a GenoMEL study
<p><b>Background</b> Carrying the cyclin-dependent kinase inhibitor 2A (CDKN2A) germline mutations is associated with a high risk for melanoma. Penetrance of CDKN2A mutations is modified by pigmentation characteristics, nevus phenotypes, and some variants of the melanocortin-1 receptor gene (MC1R), which is known to have a role in the pigmentation process. However, investigation of the associations of both MC1R variants and host phenotypes with melanoma risk has been limited.</p>
<p><b>Methods</b> We included 815 CDKN2A mutation carriers (473 affected, and 342 unaffected, with melanoma) from 186 families from 15 centers in Europe, North America, and Australia who participated in the Melanoma Genetics Consortium. In this family-based study, we assessed the associations of the four most frequent MC1R variants (V60L, V92M, R151C, and R160W) and the number of variants (1, ≥2 variants), alone or jointly with the host phenotypes (hair color, propensity to sunburn, and number of nevi), with melanoma risk in CDKN2A mutation carriers. These associations were estimated and tested using generalized estimating equations. All statistical tests were two-sided.</p>
<p><b>Results</b> Carrying any one of the four most frequent MC1R variants (V60L, V92M, R151C, R160W) in CDKN2A mutation carriers was associated with a statistically significantly increased risk for melanoma across all continents (1.24 × 10−6 ≤ P ≤ .0007). A consistent pattern of increase in melanoma risk was also associated with increase in number of MC1R variants. The risk of melanoma associated with at least two MC1R variants was 2.6-fold higher than the risk associated with only one variant (odds ratio = 5.83 [95% confidence interval = 3.60 to 9.46] vs 2.25 [95% confidence interval = 1.44 to 3.52]; Ptrend = 1.86 × 10−8). The joint analysis of MC1R variants and host phenotypes showed statistically significant associations of melanoma risk, together with MC1R variants (.0001 ≤ P ≤ .04), hair color (.006 ≤ P ≤ .06), and number of nevi (6.9 × 10−6 ≤ P ≤ .02).</p>
<p><b>Conclusion</b> Results show that MC1R variants, hair color, and number of nevi were jointly associated with melanoma risk in CDKN2A mutation carriers. This joint association may have important consequences for risk assessments in familial settings.</p>
Dipolar origin of the gas-liquid coexistence of the hard-core 1:1 electrolyte model
We present a systematic study of the effect of the ion pairing on the
gas-liquid phase transition of hard-core 1:1 electrolyte models. We study a
class of dipolar dimer models that depend on a parameter R_c, the maximum
separation between the ions that compose the dimer. This parameter can vary
from sigma_{+/-} that corresponds to the tightly tethered dipolar dimer model,
to R_c --> infinity, that corresponds to the Stillinger-Lovett description of
the free ion system. The coexistence curve and critical point parameters are
obtained as a function of R_c by grand canonical Monte Carlo techniques. Our
results show that this dependence is smooth but non-monotonic and converges
asymptotically towards the free ion case for relatively small values of R_c.
This fact allows us to describe the gas-liquid transition in the free ion model
as a transition between two dimerized fluid phases. The role of the unpaired
ions can be considered as a perturbation of this picture.Comment: 16 pages, 13 figures, submitted to Physical Review
Surface and capillary transitions in an associating binary mixture model
We investigate the phase diagram of a two-component associating fluid mixture
in the presence of selectively adsorbing substrates. The mixture is
characterized by a bulk phase diagram which displays peculiar features such as
closed loops of immiscibility. The presence of the substrates may interfere the
physical mechanism involved in the appearance of these phase diagrams, leading
to an enhanced tendency to phase separate below the lower critical solution
point. Three different cases are considered: a planar solid surface in contact
with a bulk fluid, while the other two represent two models of porous systems,
namely a slit and an array on infinitely long parallel cylinders. We confirm
that surface transitions, as well as capillary transitions for a large
area/volume ratio, are stabilized in the one-phase region. Applicability of our
results to experiments reported in the literature is discussed.Comment: 12 two-column pages, 12 figures, accepted for publication in Physical
Review E; corrected versio
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