Remittances, Inequality and Poverty: Evidence from Rural Mexico

Economic research has produced conflicting findings on the distributional impacts of migrant remittances, and there has been little research on the effects of changes in remittances on poverty. This paper utilizes new data from the Mexico National Rural Household Survey, together with inequality and poverty decomposition techniques, to explore the impacts of remittances on rural inequality and poverty. Our findings suggest that remittances from international migrants become more equalizing (or less unequalizing), as well as more effective at reducing poverty, as the prevalence of migration increases.Labor and Human Capital,

High-power nitrided TiO2 carbon felt as the negative electrode for all-vanadium redox flow batteries

This work describes the design of an electrode with enhanced performance applied to all-vanadium redox flow batteries (VRFBs). This new electrode consists of a structural porous carbon felt decorated with TiO2 rutile nanoparticles, which has been nitrided using ammonolysis at 900 °C. An outstanding charge and mass transfer over the electrode-electrolyte interface was observed as a consequence of the synergetic effect of N- and O-functionalization over carbon felt (CF) and the partial formation of TiN (metallic conductor) phase. Moreover, this material has not only improved in terms of catalysis towards the V3+/V2+ redox reaction (k0 = 1.6 × 10−3 cm s−1), but also inhibited the hydrogen evolution reaction (HER), which is one of the main causes of imbalances that lead to battery failure. This led to an impressive high-power peak output value up to 700 mW cm−2, as well as work at high current density in galvanostatic conditions (i.e. 150 mA cm−2), exhibiting low ohmic losses (overpotential) and great redox single cell reversibility, with a superior energy efficiency of 71%. An inexpensive, earth abundant and scalable synthesis method to boost VRFBs technology based on nitrided CF@TiO2 is presented, being able to overcome certain constrains, and therefore to achieve high energy and power densities

Sistemas aquosos bifásicos uma ferramenta sustentável para a extração de ácido clavulânico a partir de diferentes fontes

O ácido clavulânico (AC) é um inibidor de β-lactamases que tem vindo a ser largamente utilizado na área médica. Embora seja de extrema importância, o desenvolvimento de processos alternativos de produção e purificação é ainda insignificante, sendo fundamental o estudo de técnicas de extração mais biocompatíveis, como os Sistemas Aquosos Bifásicos (SABs). Assim, este trabalho objetivou o estudo de Sistemas Aquosos Bifásicos baseados em polímeros como uma ferramenta alternativa para a extração de AC. Foram testados dois SPAB compostos por Polietileno Glicol (PEG) com massa molecular (M) de 4000 g/mol e Poliacrilato de Sódio de 8000 g/mol, nos quais foi alterado o eletrólito indutor da formação de fases, em particular, sulfato de sódio (Na2SO4,) e cloreto de sódio (NaCl). Ademais, este trabalho visou também avaliar a eficiência de extração do AC, bem como compreender o efeito dos contaminantes no processo de migração. Para tal, foi avaliada a extração do AC a partir de três fontes distintas: solução pura (99,9%); solução comercial (60%); diretamente a partir do sobrenadante de um meio fermentando de Streptomyces clavuligerus. Os resultados obtidos demonstraram que independentemente da fonte inicial do AC, ambos os SABs poliméricos promoveram uma partição preferencial do AC para a fase rica em PEG, sendo o coeficiente de partição maior nos sistemas com Na2SO4 do que com NaCl. Após identificar a grande capacidade de partição de AC, o SAB com PEG/NaPA/Na2SO4 foi também utilizado para avaliar a partição de proteínas presente no meio fermentado, sendo também obtida uma preferencial partição destas para a fase rica em PEG. Assim, apesar da baixa capacidade de purificação de AC frente a proteínas contaminantes, os SABs estudados demonstraram que podem ser uma técnica alternativa sustentável e bastante econômica para uma etapa inicial de clarificação/concentração de bioprodutos a partir de caldos fermentados

Extended QCD(2) from dimensional projection of QCD(4)

We study an extended QCD model in (1+1) dimensions obtained from QCD in 4D by compactifying two spatial dimensions and projecting onto the zero-mode subspace. We work out this model in the large $N_c$ limit and using light cone gauge but keeping the equal-time quantization. This system is found to induce a dynamical mass for transverse gluons -- adjoint scalars in QCD(2), and to undergo a chiral symmetry breaking with the full quark propagators yielding non-tachyonic, dynamical quark masses, even in the chiral limit. We study quark-antiquark bound states which can be classified in this model by their properties under Lorentz transformations inherited from 4D. The scalar and pseudoscalar sectors of the theory are examined and in the chiral limit a massless ground state for pseudoscalars is revealed with a wave function generalizing the so called 't Hooft pion solution.Comment: JHEP class, 16 pages, 3 figures. Change in the title, some improvements in section 2, minors changes and comments added in introduction and conclusions. References added. Version appearing in JHE

Back-reaction of a conformal field on a three-dimensional black hole

The first order corrections to the geometry of the (2+1)-dimensional black hole due to back-reaction of a massless conformal scalar field are computed. The renormalized stress energy tensor used as the source of Einstein equations is computed with the Green function for the black-hole background with transparent boundary conditions. This tensor has the same functional form as the one found in the nonperturbative case which can be exactly solved. Thus, a static, circularly symmetric and asymptotically anti-de Sitter black hole solution of the semiclassical equations is found. The corrections to the thermodynamic quantities are also computed.Comment: 12 pages, RevTeX, no figure

Numerical study of pattern formation following a convective instability in non-Boussinesq fluids

We present a numerical study of a model of pattern formation following a convective instability in a non-Boussinesq fluid. It is shown that many of the features observed in convection experiments conducted on $CO_{2}$ gas can be reproduced by using a generalized two-dimensional Swift-Hohenberg equation. The formation of hexagonal patterns, rolls and spirals is studied, as well as the transitions and competition among them. We also study nucleation and growth of hexagonal patterns and find that the front velocity in this two dimensional model is consistent with the prediction of marginal stability theory for one dimensional fronts.Comment: 9 pages, report FSU-SCRI-92-6

Compressive strength and microstructure of alkali-activated blast furnace slag/sewage sludge ash (GGBS/SSA) blends cured at room temperature

In the present work, ground granulated blast furnace slag (GGBS) and sewage sludge ash (SSA) blends were assessed for the production of alkali-activated pastes and mortars. Percentages of SSA to substitute GGBS ranged from 0–30 wt.% and sodium concentrations of 6–10 mol.kg-1 were used for the activating solutions. Pastes and mortars were cured at 20 ºC for up to 90 days. Raw materials were characterised by granulometric analysis, XRF, XRD, FTIR and SEM techniques. The replacement percentage of GGBS by SSA and the sodium hydroxide concentration of the alkaline activator were optimised to produce mortar with compressive strengths close to 30 MPa after 28 curing days at room temperature. Best results were obtained in samples blended with 20 wt.% SSA activated with 6 mol.kg-1 NaOH solutions which, according to the XRD, FTIR and microscopic results, contained higher amounts of (N,C)-A-S-H gel. The potential use of SSA for the development of alternative cementitious materials at room temperature has been demonstrated

Familial Amyotrophic Lateral Sclerosis-associated Mutations Decrease the Thermal Stability of Distinctly Metallated Species of Human Copper/Zinc Superoxide Dismutase

We report the thermal stability of wild type (WT) and 14 different variants of human copper/zinc superoxide dismutase (SOD1) associated with familial amyotrophic lateral sclerosis (FALS). Multiple endothermic unfolding transitions were observed by differential scanning calorimetry for partially metallated SOD1 enzymes isolated from a baculovirus system. We correlated the metal ion contents of SOD1 variants with the occurrence of distinct melting transitions. Altered thermal stability upon reduction of copper with dithionite identified transitions resulting from the unfolding of copper-containing SOD1 species. We demonstrated that copper or zinc binding to a subset of “WT-like” FALS mutants (A4V, L38V, G41S, G72S, D76Y, D90A, G93A, and E133Δ) conferred a similar degree of incremental stabilization as did metal ion binding to WT SOD1. However, these mutants were all destabilized by ∼1–6 °C compared with the corresponding WT SOD1 species. Most of the “metal binding region” FALS mutants (H46R, G85R, D124V, D125H, and S134N) exhibited transitions that probably resulted from unfolding of metal-free species at ∼4–12 °C below the observed melting of the least stable WT species. We conclude that decreased conformational stability shared by all of these mutant SOD1s may contribute to SOD1 toxicity in FALS

A Finite Quantum Gravity Field Theory Model

We discuss the quantization of Delta gravity, a two symmetric tensors model of gravity. This model, in Cosmology, shows accelerated expansion without a cosmological constant. We present the $\tilde{\delta}$ transformation which defines the geometry of the model. Then we show that all delta type models live at one loop only. We apply this to General Relativity and we calculate the one loop divergent part of the Effective Action showing its null contribution in vacuum, implying a finite model. Then we proceed to study the existence of ghosts in the model. Finally, we study the form of the finite quantum corrections to the classical action of the model.Comment: Latex, 33 page