WUVS Simulator: Detectability of spectral lines with the WSO-UV spectrographs

The World Space Observatory - Ultraviolet (WSO-UV) space telescope is equipped with high dispersion (55,000) spectrographs working in the 1150-3100 {\AA} spectral range. To evaluate the impact of the design on the scientific objectives of the mission, a simulation software tool has been developed. This simulator builds on the development made for the PLATO space mission, and it is designed to generate synthetic time-series of images by including models of all important noise sources. In this article, we describe its design and performance. Moreover, its application to the detectability of important spectral features for star formation and exoplanetary research is addressed.Comment: 8 pages, 5 figure

Robustness of Pseudomonas 1 putida KT2440 as a host for ethanol 2 biosynthesis

Expansion of the burgeoning biofuels agenda involves not only the design of suitable genetic and metabolic devices but also their deployment into suitable hosts that can endure the stress brought about by the products themselves. The microorganisms easiest to genetically manipulate for these endeavours (e.g., Escherichia coli) are often afflicted by an undesirable sensitivity to the very product that they are engineered to synthesize. In this context, we have examined the resistance to the stress arising from ethanol synthesis and/or its addition to cultures of recombinant Pseudomonas putida, using as a benchmark the same trait in an E. coli strain. To this end, ethanologenic strains of these two species were constructed by functionally expressing pdc (pyruvate decarboxylase) and adhB (alcohol dehydrogenase) from Zymomonas mobilis. Recombinants were compared under anoxic conditions as ethanol producers, and cell survival, stress resistance, and phenotypic stability were quantified in each case. P. putida consistently outperformed E. coli in every ethanol tolerance test conducted – whether the alcohol was produced endogenously or added exogenously. These results highlight the value of such bacterium as a microbial cell factory for the production of biofuels owing to its naturally preevolved ability to withstand different kinds of chemical stresses.This study was supported by the BIO Program of the Spanish Ministry of Economy and Competitiveness, the ST-FLOW and ARIAYS Contracts of the EU, and the PROMT Project of the CAM.Peer reviewe

Pyridine nucleotide transhydrogenases enable redox balance of Pseudomonas putida during biodegra dation of aromatic compounds

Supporting informationThe metabolic versatility of the soil bacterium Pseudomonas putida is reflected by its ability to execute strong redox reactions (e.g., mono- and di-oxygenations) on aromatic substrates. Biodegradation of aromatics occurs via the pathway encoded in the archetypal TOL plasmid pWW0, yet the effect of running such oxidative route on redox balance against the background metabolism of P. putida remains unexplored. To answer this question, the activity of pyridine nucleotide transhydrogenases (that catalyze the reversible interconversion of NADH and NADPH) was inspected under various physiological and oxidative stress regimes. The genome of P. putida KT2440 encodes a soluble transhydrogenase (SthA) and a membrane-bound, proton-pumping counterpart (PntAB). Mutant strains, lacking sthA and/or pntAB, were subjected to a panoply of genetic, biochemical, phenomic and functional assays in cells grown on customary carbon sources (e.g., citrate) versus difficult-to-degrade aromatic substrates. The results consistently indicated that redox homeostasis is compromised in the transhydrogenases-defective variant, rendering the mutant sensitive to oxidants. This metabolic deficiency was, however, counteracted by an increase in the activity of NADP+ -dependent dehydrogenases in central carbon metabolism. Taken together, these observations demonstrate that transhydrogenases enable a redox-adjusting mechanism that comes into play when biodegradation reactions are executed to metabolize unusual carbon compounds.This work was supported by the EVOPROG (FP7-ICT-610730), ARISYS (ERC-2012-ADG-322797) and EmPowerPutida (EU-H2020-BIOTEC-2014-2015-6335536), Contracts of the European Union, and the CAMBIOS (RTC-2014-1777-3) and CONTIBUGS (PCIN-2013-040) projects of the Spanish Ministry of Economy and Competitiveness.Peer reviewe

Strong Shock Waves and Nonequilibrium Response in a One-dimensional Gas: a Boltzmann Equation Approach

We investigate the nonequilibrium behavior of a one-dimensional binary fluid on the basis of Boltzmann equation, using an infinitely strong shock wave as probe. Density, velocity and temperature profiles are obtained as a function of the mixture mass ratio \mu. We show that temperature overshoots near the shock layer, and that heavy particles are denser, slower and cooler than light particles in the strong nonequilibrium region around the shock. The shock width w(\mu), which characterizes the size of this region, decreases as w(\mu) ~ \mu^{1/3} for \mu-->0. In this limit, two very different length scales control the fluid structure, with heavy particles equilibrating much faster than light ones. Hydrodynamic fields relax exponentially toward equilibrium, \phi(x) ~ exp[-x/\lambda]. The scale separation is also apparent here, with two typical scales, \lambda_1 and \lambda_2, such that \lambda_1 ~ \mu^{1/2} as \mu-->0$, while \lambda_2, which is the slow scale controlling the fluid's asymptotic relaxation, increases to a constant value in this limit. These results are discussed at the light of recent numerical studies on the nonequilibrium behavior of similar 1d binary fluids.Comment: 9 pages, 8 figs, published versio

Hamiltonian systems with orbits covering densely submanifolds of small codimension

The existence of a transition chain in a Hamiltonian system leads to the existence of orbits shadowing it, if some lambda lemma can be applied. This fact has been used to prove the existence of diffusion in perturbations of integrable a priori stable systems. We prove that, under suitable conditions, there are orbits which cover densely codimension two submanifolds of the (2n - 1)-dimensional energy level. We also construct examples, near general integrable systems, where the computations to verify the sufficient conditions for the appearance of such phenomenon can be performed

An (Un)feasible Gay Planet. The Vital Intercession of Women in the Continuity of Athos in Lois McMaster Bujold's Ethan of Athos

Lois McMaster Bujold's Ethan of Athos (1986) portrays a planet only habitable by men in which homosexuality is the norm rather than celibacy, also contemplated. Nevertheless, women are not permitted to participate in this gay society since they are seen by Athosians as creatures that only bring misfortunes and jeopardize the system that governs the planet. Regardless of the fact that the autor does provide a number of eutopian elements that can be found in Athos, its exacerbated misogynistic doctrine highlights its dystopian aspects. By analysing both the eutopian and dystopian features of Athos, I argue, that the autor is not concerned with portraying either an eutopia or a dystopia as much as she is concerned with leading an Athosian, the protagonist Ethan, to acknowledge that Athos' existence cannot occur without women. As a tool to destroy Ethan's unfounded misogyny, Bujold utilises the friendship between Ethan and female mercenary Elli Quinn. In this process, Elli Quinn arises as the real hero of the novel since she not only helps and protects Ethan but also provides Athos with a priceless gift, her own ova.La novela Ethan de Athos (1986) de Lois McMaster Bujold recrea un planeta solo habitado por hombres en el que la homosexualidad es la norma a pesar de que el celibato también sea contemplado. No obstante, las mujeres no pueden participar en esta sociedad gay ya que son vistas por los Athosianos como criaturas que solo traen infortunios y que ponen en peligro el sistema que rige el planeta. Independientemente de que la autora sí introduce cierto número de elementos eutópicos que pueden ser encontrados en Athos, la exacerbada misoginia del planeta subraya sus aspectos más distópicos. Mediante el análisis de los elementos tanto eutópicos como distópicos, argumento que la autora no está preocupada en recrear ni una eutopia ni una distopía sino que lo que más le interesa es llevar a un Athosiano, el protagonista Ethan, a reconocer que la existencia de Athos no puede ocurrir sin mujeres. Como herramienta para desmoronar la misoginia sin fundamento de Ethan, Bujold utiliza la amistad entre Ethan y la mercenaria Elli Quinn. En este proceso, Elli Quinn se eleva como la verdadera heroína de la novela puesto que no solo ayuda y protege a Ethan sino que también proporciona a Athos un regalo inconmensurable, sus propios ovarios.La novel·la Ethan de Athos (1986) de Lois McMaster Bujold representa un planeta només habitat per homes en el qual l'homosexualitat és la norma malgrat que el celibat també sigui contemplat. No obstant això, les dones no poden participar en aquesta societat gai ja que són vistes pels Athosians com a criatures que únicament porten infortunis i que posen en perill el sistema que regeix el planeta. Independentment que l'autora sí introdueix cert nombre d'elements eutòpics que poden ser trobats en Athos, l'exacerbada misogínia del planeta subratlla els seus aspectes més distòpics. Mitjançant l'anàlisi dels elements tant eutòpics com distòpics, argument que l'autora no es preocupa de reprodueix ni una eutopia ni una distopia sinó que el que més li interessa és portar a un Athosià, el protagonista Ethan, a reconèixer que l'existència de Athos no pot ocórrer sense dones. Com a eina per enfonsar la misogínia sense fonament de Ethan, Bujold utilitza l'amistat entre Ethan i la mercenària Elli Quinn. En aquest procés, Elli Quinn s'eleva com la veritable heroína de la novel·la que no solament ajuda i protegeix a Ethan sinó que també proporciona a Athos un regal incommensurable, els seus propis ovaris

El col·leccionisme d’antiguitats com a mitjà de promoció social: el cas de Josep de Maranges i Marimon. Anàlisi del Compendio histórico, resumen y descripción de la antiquisima ciudad de Empurias

L’antiquarisme clàssic fou una eina de promoció social durant la Il·lustració. Un món associat també als estudis d’història antiga. Aquest article dóna mostra d’això a partir de Josep de Maranges i Marimon i el seu Compendio. L’obra aporta noves dades sobre la seva biografia i analitza les motivacions que el dugueren a escriure-la. La primera redacció del Compendio es relaciona amb una oferta al Príncep d’Astúries d’una col·lecció d’antiguitats reco- llida per Maranges. Això no fou una estratègia aïllada. La família Maranges anteriorment ja havia utilitzat aquest recurs per obrir-se nous cercles socials

Grand canonical and canonical solution of self-avoiding walks with up to three monomers per site on the Bethe lattice

We solve a model of polymers represented by self-avoiding walks on a lattice which may visit the same site up to three times in the grand-canonical formalism on the Bethe lattice. This may be a model for the collapse transition of polymers where only interactions between monomers at the same site are considered. The phase diagram of the model is very rich, displaying coexistence and critical surfaces, critical, critical endpoint and tricritical lines, as well as a multicritical point. From the grand-canonical results, we present an argument to obtain the properties of the model in the canonical ensemble, and compare our results with simulations in the literature. We do actually find extended and collapsed phases, but the transition between them, composed by a line of critical endpoints and a line of tricritical points, separated by the multicritical point, is always continuous. This result is at variance with the simulations for the model, which suggest that part of the line should be a discontinuous transition. Finally, we discuss the connection of the present model with the standard model for the collapse of polymers (self-avoiding self-attracting walks), where the transition between the extended and collapsed phases is a tricritical point.Comment: 34 pages, including 10 figure