The core-periphery model with three regions

We study a 3-region core-periphery model à la Krugman and compare our results with those of the standard 2-region model. The conditions for the stability of the dispersion and concentration configurations are established. Like in the 2-region model, dispersion and concentration can be simultaneously stable. We show that the 2- region (3-region) model favors the dispersion (concentration) of economic activity. Finally, we extend the core-periphery model to the case of n regions and show that stability of concentration with 2 regions implies stability of concentration with any even number of regions.new economic geography, core-periphery

Targeting Angiotensin Ii Type-1 Receptor (at(1)r) Inhibits The Harmful Phenotype Of Plasmodium-specific Cd8(+) T Cells During Blood-stage Malaria

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CD8(+) T-cell response is critical in the pathogenesis of cerebral malaria during blood-stage. Our group and other have been shown that angiotensin II (Ang II) and its receptor AT(1) (AT(1)R), a key effector axis of renin-angiotensin system (RAS), have immune regulatory effects on T cells. Previously, we showed that inhibition of AT(1)R signaling protects mice against the lethal disease induced by Plasmodium berghei ANKA infection However, most of the Ang II/AT(1)R actions were characterized by using only pharmacological approaches, the effects of which may not always be due to a specific receptor blockade. In addition, the mechanisms of action of the AT(1)R in inducing the pathogenic activity of Plasmodium-specific CD8(+) T cells during blood-stage were not determined. Here, we examined how angiotensin II/AT1R axis promotes the harmful response of Plasmodium-specific CD8(+) T-cell during blood-stage by using genetic and pharmacological approaches. We evaluated the response of wild-type (WT) and AT1R(-/-) Plasmodium-specific CD8(+) T cells in mice infected with a transgenic PbA lineage expressing ovalbumin; and in parallel infected mice receiving WT Plasmodium-specific CD8(+) T cells were treated with losartan (AT(1)R antagonist) or captopril (ACE inhibitor). Both, AT(1)R(-/-) OT-I cells and WT OT-I cells from losartan- or captopril-treated mice showed lower expansion, reduced IL-2 production and IL-2R? expression, lower activation (lower expression of CD69, CD44 and CD160) and lower exhaustion profiles. AT(1)R-/- OT-I cells also exhibit lower expression of the integrin LFA-1 and the chemokine receptors CCR5 and CXCR3, known to play a key role in the development of cerebral malaria. Moreover, AT1R(-/-) OT-I cells produce lower amounts of IFN-gamma and TNF-alpha and show lower degranulation upon restimulation. In conclusion, our results show the pivotal mechanisms of AT(1)R-induced harmful phenotype of Plasmodium-specific CD8(+) T cells during blood-stage malaria.7Conselho Nacional de Desenvolvimento Cientifico e Tecnologico [57.3695/2008-3, 57.3767/2008-4, 471771/2013-9, 456997/2014-8]Fundacao Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro [E-26/110.551/2010, 111681/2013, E-26/102.170/2013, E-26/201.197/2014]Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Solving Linux Upgradeability Problems Using Boolean Optimization

Managing the software complexity of package-based systems can be regarded as one of the main challenges in software architectures. Upgrades are required on a short time basis and systems are expected to be reliable and consistent after that. For each package in the system, a set of dependencies and a set of conflicts have to be taken into account. Although this problem is computationally hard to solve, efficient tools are required. In the best scenario, the solutions provided should also be optimal in order to better fulfill users requirements and expectations. This paper describes two different tools, both based on Boolean satisfiability (SAT), for solving Linux upgradeability problems. The problem instances used in the evaluation of these tools were mainly obtained from real environments, and are subject to two different lexicographic optimization criteria. The developed tools can provide optimal solutions for many of the instances, but a few challenges remain. Moreover, it is our understanding that this problem has many similarities with other configuration problems, and therefore the same techniques can be used in other domains.Comment: In Proceedings LoCoCo 2010, arXiv:1007.083

Matrix Assisted Formation of Ferrihydrite Nanoparticles in a Siloxane/Poly(Oxyethylene) Nanohybrid

Matrix-assisted formation of ferrihydrite, an iron oxide hydroxide analogue of the protein ferritin-core, in a sol-gel derived organic-inorganic hybrid is reported. The hybrid network (named di-ureasil) is composed of poly(oxyethylene) chains of different average polymer molecular weights grafted to siloxane domains by means of urea cross-linkages and accommodates ferrihydrite nanoparticles. Magnetic measurements, Fourier transform infrared and nuclear magnetic resonance spectroscopy reveal that the controlled modification of the polymer molecular weight allows the fine-tuning of the ability of the hybrid matrix to assist and promote iron coordination at the organic-inorganic interface and subsequent nucleation and growth of the ferrihydrite nanoparticles whose core size (2-4 nm) is tuned by the amount of iron incorporated. The polymer chain length, its arrangement and crystallinity, are key factors on the anchoring and formation of the ferrihydrite particles.Comment: 7 pages, 6 figures. To be published in J. Mater. Che

Fetal axillary lymphangioma

Lymphangioma is a rare congenital malformation of the lymphatic system that occur in 1 per 6000 live births. The most common site of lymphangioma is the neck (also named cystic hygroma), accounting for 75% of the cases, and it is strongly related to aneuploidies. Axillary location is very rare and appears not to be associated with chromosomal abnormalities. Tumor growth, fetal anemia secondary to intralesional bleeding, hydrops fetalis and shoulder dystocia are possible obstetric complications of this condition. The prognosis is generally good in the absence of abnormal karyotype, fetal hydrops or extension of the lymphangioma to adjacent tissues. Surgical excision or sclerotherapy are the main treatment choices. The authors present a case of a right fetal axillary lymphangioma and review the literature

Galactic Structure in the Outer Disk: The Field in the Line of Sight to the Intermediate-Age open Cluster Tombaugh 1

We employ optical photometry and high-resolution spectroscopy to study a field toward the open cluster Tombaugh 1, where we identify a complex population mixture that we describe in terms of young and old Galactic thin disks. Of particular interest is the spatial distribution of the young population, which consists of dwarfs with spectral types as early as B6 and is distributed in a blue plume feature in the color-magnitude diagram. For the first time, we confirm spectroscopically that most of these stars are early-type stars and not blue stragglers or halo/thick-disk subdwarfs. Moreover, they are not evenly distributed along the line of sight but crowd at heliocentric distances between 6.6 and 8.2 kpc. We compare these results with present-day understanding of the spiral structure of the Galaxy and suggest that they trace the outer arm. This range of distances challenges current Galactic models adopting a disk cutoff at 14 kpc from the Galactic center. The young dwarfs overlap in space with an older component, which is identified as an old Galactic thin disk. Both young and old populations are confined in space since the disk is warped at the latitude and longitude of Tombaugh 1. The main effects of the warp are that the line of sight intersects the disk and entirely crosses it at the outer arm distance and that there are no traces of the closer Perseus arm, which would then be either unimportant in this sector or located much closer to the formal Galactic plane. Finally, we analyze a group of giant stars, which turn out to be located at very different distances and to possess very different chemical properties, with no obvious relation to the other populations.Instituto de Astrofísica de La Plat

Molybdenite as a rhenium carrier : first results of a spectroscopic approach using synchrotron radiation

The chemical and physical properties of rhenium render it a highly demanded metal for advanced applications in important industrial fields. This very scarce element occurs mainly in ores of porphyry copper-molybdenum deposits associated with the mineral molybdenite, MoS2, but it has also been found in granite pegmatites and quartz veins as well as in volcanic gases. Molybdenite is a typical polytype mineral which crystal structure is based on the stacking of [S-Mo-S] with molybdenum in prismatic coordination by sulphide anions; however, it is not yet clearly established if rhenium ions replace Mo4+ cations in a disordered way or else, if such replacement gives rise to dispersed nanodomains of a rhenium-rich phase. As a contribution to clarify this question, an X-ray absorption spectroscopy (XANES) study using synchrotron radiation was performed at the Re L3-edge of rhenium-containing molybdenite samples. Obtained results are described and discussed supporting the generally accepted structural perspective that rhenium is mainly carried by molybdenite through the isomorphous replacement of Mo, rather than by the formation of dispersed Re-specific nanophase(s)