Thionins

The general designation of thionins has been proposed for a family of homologous peptides that includes purothionins, which were first isolated from wheat seeds (Balls el #/., 1942) and their homologues from various taxa that have been named viscotoxins and crambins (see Garcia-Olmedo el al., 1989). The crystalline protein material obtained from lipid extracts of wheat endosperm was designated "purothionins" because of its high sulphur content (Balls el al., 1942). This material was found to have bactericidal and fungicidal properties (Stuart and Harris, 1942), to inhibit fermentation of wheat mashes (Balls and Harris, 1944), and to be toxic to laboratory animals (Coulson el al„ 1942). The toxic properties of mistletoes were ascribed to the viscumin lectin and to a mixture of small basic proteins, designated - "viscotoxins" (Samuelsson, 1974). In a study of the seeds of the Abyssinian cabbage {Crambe abyssinica)^ a high-sulphur crystalline protein was obtained from the aqueous acetone extracts and designated "crambin" (Van Ettcn e/<?/., 1965)

Interaction and imitation in a world of Quixotes and Sanchos

Producción CientíficaThis paper studies a two-population evolutionary game in a new setting in between a symmetric and an asymmetric evolutionary model. It distinguishes two types of agents: Sanchos, whose payoffs are defined by a prisoner’s dilemma game, and Quixotes, whose payoffs are defined by a snowdrift game. Considering an imitative revision protocol, a revising agent is paired with someone from his own population or the other population. When matched, they observe payoffs, but not identities. Thus, agents in one population interact and imitate agents from their own population and from the other population. In this setting we prove that a unique mixed-strategy asymptotically stable fixed point of the evolutionary dynamics exists. Taking as an example the compliance with social norms, and depending on the parameters, two type of equilibrium are possible, one with full compliance among Quixotes and partial compliance among Sanchos, or another with partial compliance among Quixotes and defection among Sanchos. In the former type, Sanchos comply above their Nash equilibrium (as they imitate compliant Quixotes). In the latter type, Quixotes comply below their Nash equilibrium (as they imitate defecting Sanchos)

New Approaches to Oxirane Containing Natural Products: Stereoselective Total Synthesis of the Antitumor Agents Gummiferol and Depudecin

La comunicación presenta la síntesis total de productos naturales con actividad antitumoral caracterizados estructuralmente por la presencia de anillos de oxirano. Para ello se empleó una nueva metodología de epoxidación asimétrica basada en una nueva clase de iluros de azufre quirales. Mediante esta metodología se realizaron las síntesis de los productos naturales Gummiferol y DepudecinaUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Do Quasi-Hyperbolic Preferences Explain Academic Procrastination? An Empirical Evaluation

Traditional neoclassical thought fails to explain questions such as problems of self-control. Behavioural economics have explained these matters on the basis of the intertemporal preferences of individuals and, specifically, the so-called (β, δ) model which emphasises present bias. This opens the way to the analysis of new situations in which people can adopt incorrect indecisions that make it necessary for the government to intervene. The literature which has developed the (β, δ) model and its implications has generated a categorisation of people that is widely used but which lacks a systematic empirical evaluation. It is important to value the need for this public action. In this article, we develop a method which makes it possible to verify the main implications that this model has to explain the procrastination of university students. Using an experimental time discount task with real monetary incentives, we estimate the students’ β and δ parameters and we analyse their correlation with their answers to a series of questions concerning how they plan to study for an exam. The results are ambiguous given that they back some of the model’s conclusions but reject others, including a number of the most basic ones, such as the relation between present biases and some of the categories of people, these being essential to predict their behaviour

Surfaces and Interfaces for Renewable Energy

Energy is a growing need in today’s world. Citizens and governments are increasingly aware of the sustainable use that must be made of natural resources and the great negative impact on the environment produced by conventional energies. Therefore, developments in energy systems based on renewable energies must be carried out in the very near future. To ensure their sustainability, they must be made of durable materials, and for this, the study of coatings is extremely important. This is also vital in systems based on solar energy, where the optical properties of the materials must be preserved as long as possible, and to this must be added the fact that they tend to be installed in very aggressive environments from the point of view of corrosion. Therefore, this special issue aims to contribute to the development of this challenge

Proportion of common wheat kernels in commercial samples of durum wheat by chemical methods

Durum wheat (Triticum durum Desf.) is used for production of semolina which is the required raw material for the elaboration of good quality pasta products. Common wheat (T. aestivum L,)t generally used in breadmaking, yields milling products (flour or fariña) that are not suitable for that purpose. Shortage and localization of durum wheat production, as well as its higher cost, have compelled the utilization of common wheat for the production of macaroni. When different blends of hérd or soft wheat (fariña or flour) with durum wheat are used, the quality of macaroni is reduced. Por this reason, the estimation of common wheat in pasta products is an important problem from the point of view of quality and market control, Chemical methods for detection and estimation of common wheat in pasta products have been developed in this laboratory during the past six years. The related problem of estimating the proportion of common wheat kernels in commercial samples of durum wheat has been traditionally solved either by niorphológica1 examination or by cytogenetical methods. The former are too unreliable and the latter too cumbersome, In this paper, we have reviewed the above mentioned chemical methods and investigated their application to the analysis of single kernels and the estimation of the proportion of common wheat kernels in commercial samples of durum wheat in order to avoid the cytogenetical methods or to confirm the morphological examination

A contribution to the knowledge of Dermestidae (Coleoptera) from Guatemala

The following five species of Dermestidae (Coleoptera) are recorded for the first time from Guatemala: Attagenus fasciatus (Thunberg), Dermestes (Dermestinus) caninus caninus Germar, Orphinus fulvipes (Guérin-Méneville), Trogoderma simplex Jayne and Thorictodes heydeni Reitter. The species are recorded from the Guatemalan departments of Petén, Izabal and Zacapa