El papel de los lípidos en el control del crecimiento microbiano

Many foods are, or contain, emulsions. Growth of microorganisms in emulsions may lend to spoilage by bacteria, yeasts, moulds or food-poisoning bacteria. In biphasic foods (e.g. oil-in-water or water-in-oil emulsions), food structure may influence both rate of growth and conditions under which growth is initiated. The site of occupancy of microorganisms is the aqueous phase. Therefore the chemical composition of this phase is what has a direct influence on the survival and growth of microorganisms. This paper describes the chemical effects of organic acids used as preservatives in oil-in-water (acetic and lactic acids) and water-in-oil (sorbic and benzoic acids) emulsions as well as the influence of their structures on the food stability.Numerosos alimentos son, o contienen, emulsiones. El crecimiento de bacterias en las emulsiones da lugar a alteraciones debido a bacterias, levaduras, mohos o bacterias que producen intoxicaciones alimentarias. En los alimentos constituidos por dos fases (por ejemplo emulsiones aceite-agua o agua-aceite) la estructura del alimento puede influir tanto en el ritmo de crecimiento como en las condiciones en las que se inicia el crecimiento. El lugar en el que se encuentran los microorganismos es la fase acuosa. Y, por tanto, es la composición química de esta la que influye directamente en la supervivencia y el crecimiento de los microorganismos. En esta contribución se describe el efecto de los ácidos orgánicos utilizados como conservantes en las emulsiones aceite-agua (ácidos acético y lácticos) y en las de agua-aceite (ácidos sórbico y benzoicos) así como la influencia de sus estructuras en la estabilidad del alimento

The effects of feed restriction, time of day and time since feeding on behavioral and physiological indicators of hunger in broiler breeder hens

Broiler breeder chickens are commercially feed restricted to slow their growth and improve their health and production, however, there is research demonstrating that this leads to chronic hunger resulting in poor welfare. A challenge in these studies is to account for possible daily rhythms or the effects of time since last meal on measures relating hunger. To address this, we used 3 feed treatments: AL (ad libitum fed), Ram (restricted, fed in the morning), and Rpm (restricted, fed in the afternoon) to control for diurnal effects. We then conducted foraging motivation tests and collected home pen behavior and physiological samples at 4 times relative to feeding throughout a 24-h period. The feed treatment had the largest influence on the data, with AL birds weighing more, having lower concentrations of plasma NEFA, and mRNA expression of AGRP and NPY alongside higher expression of POMC in the basal hypothalamus than Ram or Rpm birds (P &lt; 0.001). R birds were more successful at and had a shorter latency to complete the motivation test, and did more walking and less feeding than AL birds in the home pen (P &lt; 0.01). There was little effect of time since last meal on many measures (P &gt; 0.05) but AGRP expression was highest in the basal hypothalamus shortly after a meal (P &lt; 0.05), blood plasma NEFA was higher in R birds just before feeding (P &lt; 0.001) and glucose was higher in Ram birds just after feeding (P &lt; 0.001), and the latency to complete the motivation test was shortest before the next meal (P &lt; 0.05). Time of day effects were mainly found in the difference in activity levels in the home pen when during lights on and lights off periods. In conclusion, many behavioral and physiological hunger measures were not significantly influenced by time of day or time since the last meal. For the measures that do change, future studies should be designed so that sampling is balanced in such a way as to minimize bias due to these effects.</p

Handschriftenkunde für Familienforscher (1925)

http://digital.ub.uni-duesseldorf.de/id/8778902 Leider schlechte Abbildungsqualität

The dilemma of Brexit: hard choices in the narrow context of British foreign policy traditions

Brexit threatens to disrupt the fabric of British foreign policy thinking. For decades, policymakers identified membership of the European Community as one of two pillars of British influence (the other being the ‘Special Relationship’ with the United States). Together, they allowed Britain to exercise power on a global as well as regional scale. These assumptions were repeated so often that the UK was regularly criticised for lacking policy imagination and avoiding hard choices when the interests of Europe and the United States conflicted. Brexit presents an unavoidable dilemma for policymakers as they chart a new course for British foreign policy. Interpretivism, as set out by Bevir and Rhodes (2003), offers a route to understanding how actors interpret and respond to such dilemmas, via reference to traditions. This article uses their approach to examine the expression of beliefs about Brexit and British foreign policy. In particular, it focuses on two datasets, one a ‘control sample’ of commentary since 2016, the other, the parliamentary debates on the first EU Withdrawal Bill in December 2018 and January 2019. We find a contrasting willingness to evoke traditions in a substantive fashion to understand and justify political choices. In particular, parliamentarians utilise one particular tradition, pragmatism, to marginalise the expression of abstract belief. In the process, they reduce discussion to a technocratic exercise that is unable to manage the conflicts Brexit has brought about. Meanwhile, those MPs that are most creative in their expression of traditions tend to be from smaller regional parties or on the political periphery. The resulting deadlock is evidence of the importance of traditions to interpreting and managing dilemmas of social change