Quantum diffusion beyond slow-roll: implications for primordial black-hole production

Primordial black-holes (PBH) can be produced in single-field models of inflation with a quasi-inflection point in the potential. In these models, a large production of PBHs requires a deviation from the slow-roll (SR) trajectory. In turn, this SR violation can produce an exponential growth of quantum fluctuations. We study the back-reaction of these quantum modes on the inflationary dynamics using stochastic inflation in the Hamilton-Jacobi formalism. We develop a methodology to solve quantum diffusion beyond SR in terms of the statistical moments of the probability distribution. We apply these techniques to a toy model potential with a quasi-inflection point. We find that there is an enhancement of the power spectrum due to the dominance of the stochastic noise in the phase beyond SR. Moreover, non-Gaussian corrections become as well relevant with a large positive kurtosis. Altogether, this produces a significant boost of PBH production. We discuss how our results extend to other single-field models with similar dynamics. We conclude that the abundance of PBHs in this class of models should be revisited including quantum diffusion.Comment: 17+7 pages, 5 figures. Matches JCAP versio

Photocarrier extraction in GaAsSb/GaAsN type-II QW superlattice solar cells

Photocarrier transport and extraction in GaAsSb/GaAsN type-II quantum well superlattices are investigated by means of inelastic quantum transport calculations based on the non-equilibrium Green's function formalism. Evaluation of the local density of states and of the spectral current flow enables the identification of different regimes for carrier localization, transport, and extraction as a function of configurational parameters. These include the number of periods, the thicknesses of the individual layers in one period, the built-in electric field, and the temperature of operation. The results for the carrier extraction efficiency are related to experimental data for different symmetric GaAsSb/GaAsN type-II quantum well superlattice solar cell devices and provide a qualitative explanation for the experimentally observed dependence of photovoltaic device performance on period thickness.Comment: 5 pages, 7 figures; accepted for publication in Applied Physics Letter

Testing the predective validity of the time trade-off and the Stardard Gamble

This paper tests the consistency of health utility measurements with individual preferences. We compare three methods, the time trade-off, the standard gamble and a version of the standard gamble that corrects for the deviations from expected utility modelled by prospect theory. Individual preferences are measured both through a ranking task and through a choice task. In decisions involving no risk the time trade-off is most consistent with people’s preferences with the standard gamble a close second. In decisions involving risk the corrected standard gamble is most consistent with people’s preferences. Our data do not support the common assumption in health economics that utility is transferable across decision contexts.Health utility measurement, QALYs,stardard gamble, time trade-off, prospect theory.

Evaluation of Organic Substrates and Microorganisms as Bio-Fertilisation Tool in Container Crop Production

Microorganisms are only effective when adequate conditions for their survival and development are provided. Among the factors that influence its effectiveness includes the type of soil or culture substrate, which works as an energy source reserve. Therefore, a tomato and a melon crop were established in different cycles to assess the effect of the physicochemical properties of organic substrates based on coconut fibre and vermicompost in three proportions, 0:100, 40:60 and 60:40 (% v:v), on the microbial activity in the rhizosphere when the bacteria Azotobacter vinelandii, Bacillus megaterium and Frateuria aurantia were applied. Concentrations of NO3−, H2PO4−, K+ and Ca2+ in the petiole cellular extract (PCE) were quantified at 60, 90 and 120 days after transplantation (DAT) for tomato and 45 and 65 DAT for melon. We analysed dehydrogenase activity (DHA), acid phosphatase activity (FTA) and β-glucosidase activity (β-GLU). In order to maintain optimal volumetric moisture for the survival of microorganisms, automatic control was used to manage the irrigation frequency between 22%–28%. The results showed that physicochemical substrate properties, by incorporating 40% vermicompost into the coconut fibre mixture, increased enzymatic activity. Plants that were inoculated with Azotobacter vinelandii and Frateuria aurantia showed an improvement in NO3− and K+ assimilation achieving highest yields

Towards the most general scalar-tensor theories of gravity: a unified approach in the language of differential forms

We use a description based on differential forms to systematically explore the space of scalar-tensor theories of gravity. Within this formalism, we propose a basis for the scalar sector at the lowest order in derivatives of the field and in any number of dimensions. This minimal basis is used to construct a finite and closed set of Lagrangians describing general scalar-tensor theories invariant under Local Lorentz Transformations in a pseudo-Riemannian manifold, which contains ten physically distinct elements in four spacetime dimensions. Subsequently, we compute their corresponding equations of motion and find which combinations are at most second order in derivatives in four as well as arbitrary number of dimensions. By studying the possible exact forms (total derivatives) and algebraic relations between the basis components, we discover that there are only four Lagrangian combinations producing second order equations, which can be associated with Horndeski's theory. In this process, we identify a new second order Lagrangian, named kinetic Gauss-Bonnet, that was not previously considered in the literature. However, we show that its dynamics is already contained in Horndeski's theory. Finally, we provide a full classification of the relations between different second order theories. This allows us to clarify, for instance, the connection between different covariantizations of Galileons theory. In conclusion, our formulation affords great computational simplicity with a systematic structure. As a first step we focus on theories with second order equations of motion. However, this new formalism aims to facilitate advances towards unveiling the most general scalar-tensor theories.Comment: 28 pages, 1 figure, version published in PRD (minor changes

The influence of the Ratio Bias phenomenon on the elicitation of Standard Gamble utilities

This paper tests whether logically equivalent risk formats can lead to different health state utilities elicited by means of the standard gamble (SG) method. We compare SG utilities elicited when probabilities are framed in terms of frequencies with respect to 100 people in the population (i.e., X out of 100) with SG utilities elicited for frequencies with respect to 1,000 people in the population (i.e., Y out of 1,000). We found that utilities were significant higher when success and failure probabilities were framed as frequencies type “Y out of 1,000” rather than as frequencies type “X out of 100”. This framing effect, known as Ratio Bias, may have important consequences in resource allocation decisions.Framing effect, risk format, standard gamble, health state, dual-process theories.

Hepatocellular carcinoma and multidrug resistance: Past, present and new challenges for therapy improvement

Hepatocellular carcinoma (HCC) is the most common malignancy of the liver and the third cause of cancer death worldwide. Chronic hepatitis due to HBV and HCV infection are two major risk factors for HCC worldwide. Advances in early detection and treatment have improved life expectancy of patients with HCC. However, this disorder remains as a disease with poor prognosis. In fact, epidemiological studies have shown that the median survival of patients is 8 months and approximately 20% of them survive one year, while only 5% remain alive after three years. Additionally, HCC is particularly difficult to treat because of its high recurrence rate, and its resistance to conventional chemotherapy due to, among other mechanisms, the over-expression of several members of the ATP-Binding Cassette (ABC) protein family involved in drugs transport. Fortunately, there is evidence that these patients may benefit from alternative molecular-targeted therapies. This manuscript reviews the current knowledges on the etiology, molecular mechanisms involved in HCC development and the current therapy strategies for the management of this malignancy. The challenges in the development of drug delivery systems for the targeting of antitumoral drugs to the liver parenchyma are also discussed. Finally, perspectives in the design of a more efficient pharmacotherapy to overcome multidrug resistance are reviewed.Fil: Cuestas, María Luján. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Oubiña, Jose Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Mathet, Veronica Lidia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; Argentin

Evaluating land administration systems: a comparative method with an application to Peru and Honduras

This article develops a methodology for the evaluation of land administration systems. We propose a set of quantitative and qualitative indicators with benchmarks for each one of them that signal possible venues to improve the administration’s structure and budgetary/management arrangements, in order to bring about the following goals: (1) to contribute to public sector financing through taxes; (2) to encourage the productive and sustainable use of land, and (3) to facilitate access to land for low-income citizens. This methodology was applied to the cases of Honduras and Peru in order to refine our draft evaluation indicators, while evaluating the systems of both countries. Here we present the final refined indicators and benchmarks, and the conclusions from both case studies.land administration systems; cadastre; evaluation; performance indicators

Dynamic Modelling and Optimisation of Large-Scale Cryogenic Separation Processes

In this work, the open loop dynamic optimisation of a large-scale natural gas processing plant is performed. A rigorous differential-algebraic equation (DAE) model has been formulated to represent main plant units, such as shell and tube heat exchangers, highpressure separator and demethanizing column. In the shell and tube heat exchangers, the hot stream partially condenses and equations to consider the partial condensation of the fluids have been included. A rigorous index one model for the demethanizing column has been developed. The DAE optimisation problem is solved with a simultaneous approach, in which both state and control variables are discretised and the original DAE optimisation model is transformed into a large-scale nonlinear problem (NLP), which is solved using Sequential Quadratic Programming (SQP) methods. Optimal profiles have been obtained for main operating variables to achieve an enhanced product recovery.Fil: Rodriguez, Mariela Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Bandoni, Jose Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Díaz, María Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentin