Environmental characterisation to guide breeding decisions in a changing climate

Substantial evidence now exists suggesting that agricultural yields will have to increase significantly in order to meet food needs during the 21st century. One such way of increasing yields is to develop high yielding cultivars through crop improvement. This Working Paper summarises the results of a CCAFS project named Target Population of Environments (TPE). The project aimed at providing actionable information to crop breeders and, therefore, inform breeding decisions. We developed and applied a methodology for classifying crop growing environments, determining stress profiles and, finally, assessing the potential benefit of improved breeding practice. We present two contrasting case studies, one for upland rice in central Brazil and another for common beans in Goiás (Brazil). Analyses are also currently being conducted for lowland irrigated rice in Colombia, and plans to conduct research on rice in sub-Saharan Africa. Results of the TPE project are publicly available in the form of dynamic maps and graphs at http://www.ccafs-tpe.org

The impact of online technologies and English Medium Instruction on university lectures in international learning contexts: A systematic review

This paper addresses how the university lecture is evolving in response to new realities in international higher education driven by two important trends: innovative online instructional technologies and the rise of English Medium Instruction (EMI). Following a brief review of the lecture as the core instructional channel in universities, we offer a detailed overview of the new technology-driven lecture formats that are now available to learners worldwide. We then shift the focus to the role of EMI, with particular attention to understanding how both instructors and students view this relatively new approach to learning. This was accomplished through a systematic review of EMI-related literature available on scholarly databases. Findings showed that most research has focused on the language-related issues of learners, and little attention has been paid to the crucial issue of lecture comprehension, which is mainly caused by the low level of proficiency of students/instructors and domain-specific vocabulary. Moreover, studies have almost exclusively addressed face-to-face settings, indicating a need to expand EMI research to include online lecture settings that are increasingly frequent in international higher education. This paper contributes to the body of knowledge relating to new trends in how lectures are experienced and perceived in international educational settings

Air gap influence on the vibro-acoustic response of Solar Arrays during launch

One of the primary elements on the space missions is the electrical power subsystem, for which the critical component is the solar array. The behaviour of these elements during the ascent phase of the launch is critical for avoiding damages on the solar panels, which are the primary source of energy for the satellite in its final configuration. The vibro-acoustic response to the sound pressure depends on the solar array size, mass, stiffness and gap thickness. The stowed configuration of the solar array consists of a multiple system composed of structural elements and the air layers between panels. The effect of the air between panels on the behaviour of the system affects the frequency response of the system not only modifying the natural frequencies of the wings but also as interaction path between the wings of the array. The usual methods to analyze the vibro-acoustic response of structures are the FE and BE methods for the low frequency range and the SEA formulation for the high frequency range. The main issue in the latter method is, on one hand, selecting the appropriate subsystems, and, on the other, identifying the parameters of the energetic system: the internal and coupling loss factors. From the experimental point of view, the subsystems parameters can be identified by exciting each subsystem and measuring the energy of all the subsystems composing the Solar Array. Although theoretically possible, in practice it is difficult to apply loads on the air gaps. To analyse this situation, two different approaches can be studied depending on whether the air gaps between the panels are included explicitly in the problem or not. For a particular case of a solar array of three wings in stowed configuration both modelling philosophies are compared. This stowed configuration of a three wing solar arrays in stowed configuration has been tested in an acoustic chamber. The measured data on the solar wings allows, in general, determining the loss factors of the configuration. The paper presents a test description and measurements on the structure, in terms of the acceleration power spectral density. Finally, the performance of each modelling technique has been evaluated by comparison between simulations with experimental results on a spacecraft solar array and the influence on the apparent properties of the system in terms of the SEA loss factors has been analyse

Train-induced pressure on pedestrians

A simple analytical model for the train-induced flow and its effects on pedestrians is presented in this paper. The expressions developed for the induced air velocity and pressure on the pedestrian surface, as well as their dependence with time, are obtained from unsteady potential theory. The relevant parameters and their effects are analysed, in particular the sensitivity of the pressure coefficient and its rate of change on the train and pedestrian transverse size, the distance to the tracks and the pressure measurement location on the pedestrian surface. In spite of the extreme simplicity of the model and the expressions obtained, good correlation is observed with previously existing experiments. With this work, an absence of published studies concerning analytical approaches to the problem of vehicle-induced pressure on pedestrians is intended to be covered, allowing for simplified testing procedures

Riesgo moral y contratos: cierta evidencia experimental

This paper shows one type of asymmetric information problems, their theoretical implications, the design of contracts that mitigate them, as well as some experimental evidence. Furthermore, by extrapolating the results, the paper tries to illustrate certain macroeconomic implications obtained under a controlled environment.moral risk, contracts, experimental evidence, asymmetric information

Expression of Brugmansia candida Hyoscyamine 6beta-Hydroxylase gene in Saccharomyces cerevisiae and its potential use as biocatalyst

<p>Abstract</p> <p>Background</p> <p>Tropane alkaloids, mainly hyoscyamine and scopolamine, are widely used in medicine due to their anticholinergic activity. Scopolamine has a higher demand being the more valuable alkaloid due to its fewer side effects and higher physiological activity. Anisodamine (6β-hydroxyhyoscyamine) is the intermediate in the conversion of hyoscyamine into scopolamine. Current studies report that this alkaloid is potentially applicable in medicine. The gene that codifies for Hyoscyamine 6-β hydroxylase, the enzyme responsible for hyoscyamine hydroxylation and epoxidation, leading to scopolamine was isolated from <it>Brugmansia candida</it>.</p> <p>Results</p> <p>The <it>h6h</it>cDNA was cloned into pYES2.1 and pYES2.1/V5-His-TOPO vectors to produce an untagged and a tagged protein, respectively. The H6H enzyme was produced in <it>Saccharomyces cerevisiae </it>in order to obtain a biological catalyst for potential industrial applications. Protein extracts of the induced yeast were analyzed by Western blot. The expression was detected 4 h after induction and no degradation was observed during the period assayed. The tagged and the untagged proteins were able to transform hyoscyamine, showing a functional expression of the <it>h6h</it>cDNA.</p> <p>Conclusion</p> <p>The strains obtained in this work are promising and potentially applicable in biocatalytic processes.</p

Large scale structure simulations of inhomogeneous LTB void models

We perform numerical simulations of large scale structure evolution in an inhomogeneous Lemaitre-Tolman-Bondi (LTB) model of the Universe. We follow the gravitational collapse of a large underdense region (a void) in an otherwise flat matter-dominated Einstein-deSitter model. We observe how the (background) density contrast at the centre of the void grows to be of order one, and show that the density and velocity profiles follow the exact non-linear LTB solution to the full Einstein equations for all but the most extreme voids. This result seems to contradict previous claims that fully relativistic codes are needed to properly handle the non-linear evolution of large scale structures, and that local Newtonian dynamics with an explicit expansion term is not adequate. We also find that the (local) matter density contrast grows with the scale factor in a way analogous to that of an open universe with a value of the matter density OmegaM(r) corresponding to the appropriate location within the void.Comment: 7 pages, 6 figures, published in Physical Review

Calibration of accelerometers for the measurement of microvibrations

The accelerometers used for the measurement of microvibrations or microgravity applications, such as active control of space structures, attitude control, scientific payloads, or even on-Earth testing of structures at very low-excitation levels, require a dedicated calibration procedure that includes the gravitational effects. Otherwise, on-Earth calibrations can be inaccurate due to the collateral projection of the local gravity onto the sensitive axis. An on-Earth calibration technique for the 107102s amplitude range and 0-100-Hz frequency range is described. Special attention has been given to the modeling of gravitational effects on the response of the calibration device and the accelerometer itself. The sensitivity and resolution tests performed on piezoelectric accelerometers showthe accuracy andthe potential of thistechnique. Typical scale factorun certainty, which hasbeen carefully analyzed, is of the order of 2% at acceleration levels of 10sg

Spacecraft launch depressurization loads

The pressure variation inside the launch vehicle fairing during climb through the atmosphere induces structural loads on the walls of closed-type spacecrafts or equipment boxes. If the evacuation of the air is not fast enough, excessive pressure loading can result in damage of elements exposed to the rising pressure jump, which depends mainly on the geometry of venting holes, the effective volume of air to be evacuated, and the characteristic time of pressure variation under the fairing. A theoretical study of the reservoir discharge forced by the fairing time-dependent pressure variation is presented. The basic mathematical model developed can yield both a numerical solution for the pressure jump and an asymptotic solution for the most relevant case, the small-prcssurc-jump limit, showing the dependence on a single nondimensional parameter: the ratio of the reservoir discharge to the fairing pressure profile characteristic times. The asymptotic solution validity range upper limit, obtained by comparison with the numerical solution, is determined by the starting of choked operation. Very high sensitivity of the maximum pressure jump to the ratio of characteristic times has been observed. Another relevant finding is that the pressure profiles for different launchers can be considered similar when rewritten in appropriate form and only their characteristic times are required for the analysis. The simple expressions of the asymptotic solution are a useful tool for preliminarily sizing the reservoir discharge geometry and estimating depressurization load