Strategic Wage Setting and Coordination Frictions with Multiple Applications

We examine wage competition in a model where identical workers choose the number of jobs to apply for and identical firms simultaneously post a wage. The Nash equilibrium of this game exhibits the following properties: (i) an equilibrium where workers apply for just one job exhibits unemployment and absence of wage dispersion; (ii) an equilibrium where workers apply for two or for more (but not for all) jobs always exhibits wage dispersion and, typically, unemployment; (iii) the equilibrium wage distribution with a higher vacancy-to-unemployment ratio first-order stochastically dominates the wage distribution with a lower level of labor market tightness; (iv) the average wage is non-monotonic in the number of applications; (v) the equilibrium number of applications is non-monotonic in the vacancy-to-unemployment ratio; (vi) a minimum wage increase can be welfare improving because it compresses the wage distribution and reduces the congestion effects cause! d by the socially excessive number of applications; and (vii) the only way to obtain efficiency is to impose a mandatory wage that eliminates wage dispersion altogether

Human metapneumovirus: Mechanisms and molecular targets used by the virus to avoid the immune system

Indexación: Scopus.This work was supported by Comisión Nacional de Investigación Científica y Tecnolígica (CONICYT) N◦21151028 and FONDECYT (N◦1070352 and N◦1170964) and the Millennium Institute on Immunology and Immunotherapy (P09/016-F).Human metapneumovirus (hMPV) is a respiratory virus, first reported the year 2001. Since then, it has been described as one of the main etiological agents that causes acute lower respiratory tract infections (ALRTIs), which is characterized by symptoms such as bronchiolitis, wheezing and coughing. Susceptible population to hMPV-infection includes newborn, children, elderly and immunocompromised individuals. This viral agent is a negative-sense, single-stranded RNA enveloped virus, that belongs to the Pneumoviridae family and Metapneumovirus genus. Early reports-previous to 2001-state several cases of respiratory illness without clear identification of the responsible pathogen, which could be related to hMPV. Despite the similarities of hMPV with several other viruses, such as the human respiratory syncytial virus or influenza virus, mechanisms used by hMPV to avoid the host immune system are still unclear. In fact, evidence indicates that hMPV induces a poor innate immune response, thereby affecting the adaptive immunity. Among these mechanisms, is the promotion of an anergic state in T cells, instead of an effective polarization or activation, which could be induced by low levels of cytokine secretion. Further, the evidences support the notion that hMPV interferes with several pattern recognition receptors (PRRs) and cell signaling pathways triggered by interferon-associated genes. However, these mechanisms reported in hMPV are not like the ones reported for hRSV, as the latter has two non-structural proteins that are able to inhibit these pathways. Several reports suggest that viral glycoproteins, such as G and SH, could play immune-modulator roles during infection. In this work, we discuss the state of the art regarding the mechanisms that underlie the poor immunity elicited by hMPV. Importantly, these mechanisms will be compared with those elicited by other common respiratory viruses. © 2018 Frontiers Media S.A. All rights reserved.https://www.frontiersin.org/articles/10.3389/fimmu.2018.02466/ful

Bioscorodite: biological crystallization of scorodite for arsenic removal

The use of arsenic is banned for most applications, leading to its accumulation as arsenic trioxide and ferric arsenate sludge. The aim of this thesis was to develop a controlled process for biological crystallization of scorodite from metallurgical streams. In this thesis, the proof of principle, reactor selection and operational conditions of bioscorodite crystallization were studied. The results from this thesis resulted in the ARSENOTEQTM process, currently commercialized by Paques B.V. (Balk, The Netherlands). The bioscorodite process in practice occurs in a continuous airlift reactor at pH </p

Bioscorodite crystallization for arsenic removal

In the bio-scorodite process, arsenic is precipitated as crystalline iron arsenate, i.e. scorodite (FeAsO4·2H2O). This is a more economic and more environmentally friendly method for arsenic immobilization than the chemical production of iron- or calcium arsenate, as fewer chemicals are needed. Moreover, scorodite is an attractive medium for arsenic control and immobilization because it is stable, compact and has a very low solubility. Therefore it is regarded as the most ideal form for long-term arsenic storage. We have demonstrated that bio-crystallization of arsenic into scorodite crystals is possible with the aid of microorganisms. The operational conditions of the bio-scorodite process allow for a fast growth of the microorganisms and facilitate the crystallization of scorodite, avoiding the precipitation of other iron oxides or amorphous iron arsenates. The bio-scorodite process brings several advantages compared to chemical crystallization such as the lower required temperature (70°C), the control of supersaturation by biological oxidation and no need for crystal parents or seeds to begin the crystallization. Arsenic concentrations are removed to ppm level with starting concentrations ranging from 1000 to 2000 mg L-1. The produced bioscorodite crystals are very similar to the scorodite mineral found in nature. By control of the iron feed and the pH, the production of other iron precipitates is avoided. The latter facilitates easy separation of the solid product. Based on their highly crystalline nature, the biogenic scorodite crystals seem very suitable for safe disposal. At present the research has started with the continuous production of scorodite in bioreactors. The follow-up challenges are focused on the selection of a suitable reactor configuration

Homestake result, sterile neutrinos and low energy solar neutrino experiments

The Homestake result is about ~ 2 \sigma lower than the Ar-production rate, Q_{Ar}, predicted by the LMA MSW solution of the solar neutrino problem. Also there is no apparent upturn of the energy spectrum (R \equiv N_{obs}/N_{SSM}) at low energies in SNO and Super-Kamiokande. Both these facts can be explained if a light, \Delta m^2_{01} ~ (0.2 - 2) \cdot 10^{-5} eV^2, sterile neutrino exists which mixes very weakly with active neutrinos: \sin^2 2\alpha ~ (10^{-5} - 10^{-3}). We perform both the analytical and numerical study of the conversion effects in the system of two active neutrinos with the LMA parameters and one weakly mixed sterile neutrino. The presence of sterile neutrino leads to a dip in the survival probability in the intermediate energy range E = (0.5 - 5) MeV thus suppressing the Be, or/and pep, CNO as well as B electron neutrino fluxes. Apart from diminishing Q_{Ar} it leads to decrease of the Ge-production rate and may lead to decrease of the BOREXINO signal and CC/NC ratio at SNO. Future studies of the solar neutrinos by SNO, SK, BOREXINO and KamLAND as well as by the new low energy experiments will allow us to check this possibility. We present a general analysis of modifications of the LMA energy profile due to mixing with new neutrino states.Comment: Figures 5 and 6 modified, shorter version will be published in PR

Fermi Liquid Properties of a Two Dimensional Electron System With the Fermi Level Near a van Hove Singularity

We use a diagrammatic approach to study low energy physics of a two dimensional electron system where the Fermi level is near van-Hove singularies in the energy spectrum. We find that in most regions of the $\epsilon_F-T$ phase diagram the system behaves as a normal Fermi liquid rather than a marginal Fermi liquid. Particularly, the imaginary part of the self energy is much smaller than the excitation energy, which implies well defined quasiparticle excitations, and single particle properties are only weakly affected by the presence of the van-Hove singularities. The relevance to high temperature superconductivity is also discussed.Comment: 10 pages, 4 postscript figure

Interplay between lattice-scale physics and the quantum Hall effect in graphene

Graphene's honeycomb lattice structure underlies much of the remarkable physics inherent in this material, most strikingly through the formation of two ``flavors'' of Dirac cones for each spin. In the quantum Hall regime, the resulting flavor degree of freedom leads to an interesting problem when a Landau level is partially occupied. Namely, while Zeeman splitting clearly favors polarizing spins along the field, precisely how the states for each flavor are occupied can become quite delicate. Here we focus on clean graphene sheets in the regime of quantum Hall ferromagnetism, and discuss how subtler lattice-scale physics, arising either from interactions or disorder, resolves this ambiguity to measurable consequence. Interestingly, such lattice-scale physics favors microscopic symmetry-breaking order coexisting with the usual liquid-like quantum Hall physics emerging on long length scales. The current experimental situation is briefly reviewed in light of our discussion.Comment: 6 pages, 2 figures; short revie

Kinetics of ferrous iron oxidation by batch and continuous cultures of thermoacidophilic Archaea at extremely low pH of 1.1–1.3

The extreme acid conditions required for scorodite (FeAsO4·2H2O) biomineralization (pH below 1.3) are suboptimal for growth of most thermoacidophilic Archaea. With the objective to develop a continuous process suitable for biomineral production, this research focuses on growth kinetics of thermoacidophilic Archaea at low pH conditions. Ferrous iron oxidation rates were determined in batch-cultures at pH 1.3 and a temperature of 75°C for Acidianus sulfidivorans, Metallosphaera prunea and a mixed Sulfolobus culture. Ferrous iron and CO2 in air were added as sole energy and carbon source. The highest growth rate (0.066 h-1) was found with the mixed Sulfolobus culture. Therefore, this culture was selected for further experiments. Growth was not stimulated by increase of the CO2 concentration or by addition of sulphur as an additional energy source. In a CSTR operated at the suboptimal pH of 1.1, the maximum specific growth rate of the mixed culture was 0.022 h-1, with ferrous iron oxidation rates of 1.5 g L-1 d-1. Compared to pH 1.3, growth rates were strongly reduced but the ferrous iron oxidation rate remained unaffected. Influent ferrous iron concentrations above 6 g L-1 caused instability of Fe2+ oxidation, probably due to product (Fe3+) inhibition. Ferric-containing, nano-sized precipitates of K-jarosite were found on the cell surface. Continuous cultivation stimulated the formation of an exopolysaccharide-like substance. This indicates that biofilm formation may provide a means of biomass retention. Our findings showed that stable continuous cultivation of a mixed iron-oxidizing culture is feasible at the extreme conditions required for continuous biomineral formation

Expansion for the solutions of the Bogomolny equations on the torus

We show that the solutions of the Bogomolny equations for the Abelian Higgs model on a two-dimensional torus, can be expanded in powers of a quantity epsilon measuring the departure of the area from the critical area. This allows a precise determination of the shape of the solutions for all magnetic fluxes and arbitrary position of the Higgs field zeroes. The expansion is carried out to 51 orders for a couple of representative cases, including the unit flux case. We analyse the behaviour of the expansion in the limit of large areas, in which case the solutions approach those on the plane. Our results suggest convergence all the way up to infinite area.Comment: 26 pages, 8 figures, slightly revised version as published in JHE