Classical and Quantum Signatures of Quantum Phase Transitions in a (Pseudo) Relativistic Many-Body System

We identify a (pseudo) relativistic spin-dependent analogue of the celebrated quantum phase transition driven by the formation of a bright soliton in attractive one-dimensional bosonic gases. In this new scenario, due to the simultaneous existence of the linear dispersion and the bosonic nature of the system, special care must be taken with the choice of energy region where the transition takes place. Still, due to a crucial adiabatic separation of scales, and identified through extensive numerical diagonalization, a suitable effective model describing the transition is found. The corresponding mean-field analysis based on this effective model provides accurate predictions for the location of the quantum phase transition when compared against extensive numerical simulations. Furthermore, we numerically investigate the dynamical exponents characterizing the approach from its finite-size precursors to the sharp quantum phase transition in the thermodynamic limit

Emergence of a renormalized 1/N expansion in quenched critical many-body systems

We consider the fate of 1/N expansions when a many-body quantum system is quenched across criticality and show the emergence of exp(2λt)/N as renormalized parameter ruling the quantum-classical transition and accounting non-perturbatively for the local divergence rate λ of mean-field solutions. In terms of exp(2λt)/N, quasiclassical expansions of paradigmatic examples of criticality like the selftrapping transition in an integrable Bose-Hubbard dimer and the generic instability of atractive bosonic systems towards soliton formation, are pushed to arbitrarily high orders. The agreement with numerical simulations supports the general nature of our results in the appropriately combined long-time λt → ∞ quasiclassical N → ∞ regime, out of reach of expansions in the bare parameter 1/N. For scrambling in many-body hyperbolic systems, our results provide formal grounds to a conjectured multi-exponential form of out-of-time-ordered correlators

Semiclassics in a system without classical limit: The few-body spectrum of two interacting bosons in one dimension

xWe present a semiclassical study of the spectrum of a few-body system consisting of two short-range interacting bosonic particles in one dimension, a particular case of a general class of integrable many-body systems where the energy spectrum is given by the solution of algebraic transcendental equations. By an exact mapping between delta-potentials and boundary conditions on the few-bodywave functions, we are able to extend previous semiclassical results for single-particle systems with mixed boundary conditions to the two-body problem. The semiclassical approach allows us to derive explicit analytical results for the smooth part of the two-body density of states that are in excellent agreement with numerical calculations. It further enables us to include the effect of bound states in the attractive case. Remarkably, for the particular case of two particles in one dimension, the discrete energy levels obtained through a requantization condition of the smooth density of states are essentially in perfect agreement with the exact ones

Nonlocal pair correlations in Lieb-Liniger gases -- a unified non-perturbative approach from weak degeneracy to high temperatures

We present analytical results for the nonlocal pair correlations in one-dimensional bosonic systems with repulsive contact interactions that are uniformly valid from the classical regime of high temperatures down to weak quantum degeneracy entering the regime of ultralow temperatures. By using the information contained in the short-time approximations of the full many-body propagator we derive results that are non-perturbative in the interaction parameter while covering a wide range of temperatures and densities. For the case of three particles we give a simple formula for arbitrary couplings that is exact in the dilute limit while remaining valid up to the regime where the thermal de Broglie wavelength λT is of the order of the characteristic length L of the system. We then show how to use this result to find analytical expressions for the nonlocal correlations for arbitrary but fixed particle numbers N including finite size corrections. Neglecting the latter in the thermodynamic limit provides an expansion in the quantum degeneracy parameter NλT/L. We compare our analytical results with numerical Bethe ansatz calculations finding excellent agreement

Implementing Green Infrastructure for the Spatial Planning of Peri-Urban Areas in Geneva, Switzerland

The concept of green infrastructure (GI) seeks to identify and prioritize areas of high ecological value for wildlife and people, to improve the integration of natural values in landscape planning decisions. In 2018, the canton of Geneva, Switzerland, established a roadmap for biodiversity conservation, which includes the operationalization of GI covering 30% of the territory by 2030. In this paper, we demonstrate a GI mapping framework in the canton of Geneva. Our approach is based on the combined assessment of three 'pillars', namely species' distribution, landscape structure and connectivity, and ecosystem services, to optimize the allocation of conservation actions using the spatial prioritization software, Zonation. The identified priority conservation areas closely overlap existing natural reserves. Including the three pillars in the landscape prioritization should also improve adhesion to the GI idea, without undermining the protection of threatened species. With regards to land use planning, public and private land parcels with high values for GI may require specific incentives to maintain their desirable characteristics, as they are more likely to be degraded than areas with more building restrictions. Visualizing priority conservation areas in a spatially explicit manner will support decision-makers in Geneva to optimally allocate limited resources for ecosystem preservation.Peer reviewe

Match Job

Web pageEl presente proyecto, al cual denominamos “Match Job”, nace a partir de la problemática que se da en la búsqueda de oportunidades laborales. En este caso, identificamos que estos problemas se desarrollan en las etapas de procesos de selección, en donde no existe comunicación oportuna por parte de las empresas reclutadoras y los portales de empleo. Para el desarrollo de este proyecto, nos enfocamos a jóvenes estudiantes los cuales buscan oportunidades de trabajo a partir de sus últimos ciclos, los cuales desean informarse y adaptarse a un mercado tan competitivo como el de hoy en día. Para proceder con el avance efectivo de este proyecto académico, realizamos diversos experimentos para identificar y validar la problemática relacionada a la búsqueda de empleo en estudiantes y la insatisfacción de estos al momento de participar en un proceso de selección. Asimismo, creamos un prototipo de página web (prototipo de alta fidelidad) y redes sociales para solucionar dicho problema, creando contenido audiovisual de valor y campañas pagadas para generar tráfico y clientes potenciales.This project, which we call "Match Job", was born from the problems that arise in the search for job opportunities. In this case, we identify that these problems develop in the selection process stages, where there is no timely communication from recruitment companies and job portals. For the development of this project, we focus on young students who are looking for job opportunities from their last cycles, who want to learn and adapt to a market as competitive as today. To proceed with the effective advancement of this academic project, we carried out various experiments to identify and validate the problems related to the search for employment in students and their dissatisfaction at the time of participating in a selection process. Likewise, we created a website prototype (high fidelity prototype) and social networks to solve this problem, creating valuable audiovisual content and paid campaigns to generate traffic and potential customers.Trabajo de investigació

Magic-angle spinning 31 P NMR spectroscopy of condensed phosphates in parasitic protozoa: visualizing the invisible

Abstract We report the results of a solid-state 31 P nuclear magnetic resonance (NMR) spectroscopic investigation of the acidocalcisome organelles from Trypanosoma brucei (bloodstream form), Trypanosoma cruzi and Leishmania major (insect forms). The spectra are characterized by a broad envelope of spinning sidebands having isotropic chemical shifts at V V0, 3 37 and 3 321 ppm. These resonances are assigned to orthophosphate, terminal (K K) phosphates of polyphosphates and bridging (L L) phosphates of polyphosphates, respectively. The average polyphosphate chain length is V V3.3 phosphates. Similar results were obtained with whole L. major promastigotes. 31 P NMR spectra of living L. major promastigotes recorded under conventional solution NMR conditions had spectral intensities reduced with respect to solution-state NMR spectra of acid extracts, consistent with the invisibility of the solid-state phosphates. These results show that all three parasites contain large stores of condensed phosphates which can be visualized by using magic-angle spinning NMR techniques. ß 2002 Published by Elsevier Science B.V. on behalf of the Federation of European Biochemical Societies

Impacts of Global Change on Mediterranean Forests and Their Services

The increase in aridity, mainly by decreases in precipitation but also by higher temperatures, is likely the main threat to the diversity and survival of Mediterranean forests. Changes in land use, including the abandonment of extensive crop activities, mainly in mountains and remote areas, and the increases in human settlements and demand for more resources with the resulting fragmentation of the landscape, hinder the establishment of appropriate management tools to protect Mediterranean forests and their provision of services and biodiversity. Experiments and observations indicate that if changes in climate, land use and other components of global change, such as pollution and overexploitation of resources, continue, the resilience of many forests will likely be exceeded, altering their structure and function and changing, mostly decreasing, their capacity to continue to provide their current services. A consistent assessment of the impacts of the changes, however, remains elusive due to the difficulty of obtaining simultaneous and complete data for all scales of the impacts in the same forests, areas and regions. We review the impacts of climate change and other components of global change and their interactions on the terrestrial forests of Mediterranean regions, with special attention to their impacts on ecosystem services. Management tools for counteracting the negative effects of global change on Mediterranean ecosystem- services are finally discussed

Overweight status is associated with extensive signs of microvascular dysfunction and cardiovascular risk

The aim of this present study was to investigate if overweight individuals exhibit signs of vascular dysfunction associated with a high risk for cardiovascular disease (CVD). One hundred lean and 100 overweight participants were recruited for the present study. Retinal microvascular function was assessed using the Dynamic Retinal Vessel Analyser (DVA), and systemic macrovascular function by means of flow-mediated dilation (FMD). Investigations also included body composition, carotid intimal-media thickness (c-IMT), ambulatory blood pressure monitoring (BP), fasting plasma glucose, triglycerides (TG), cholesterol levels (HDL-C and LDL-C), and plasma von Willebrand factor (vWF). Overweight individuals presented with higher right and left c-IMT (p = 0.005 and p = 0.002, respectively), average 24-h BP values (all p <0.001), plasma glucose (p = 0.008), TG (p = 0.003), TG: HDL-C ratio (p = 0.010), and vWF levels (p = 0.004). Moreover, overweight individuals showed lower retinal arterial microvascular dilation (p = 0.039) and baseline-corrected flicker (bFR) responses (p = 0.022), as well as, prolonged dilation reaction time (RT, p = 0.047). These observations emphasise the importance of vascular screening and consideration of preventive interventions to decrease vascular risk in all individuals with adiposity above normal range