ABSTRACT
Colour signals of many animals are surrounded by a high-contrast achromatic background, but little is known about the possible function of this arrangement. For both humans and non-human animals, the background colour surrounding a colour stimulus affects the perception of that stimulus, an effect that can influence detection and discrimination of colour signals. Specifically, high colour contrast between the background and two given colour stimuli makes discrimination more difficult. However, it remains unclear how achromatic background contrast affects signal discrimination in non-human animals. Here, we test whether achromatic contrast between signal-relevant colours and an achromatic background affects the ability of zebra finches to discriminate between those colours. Using an odd-one-out paradigm and generalized linear mixed models, we found that higher achromatic contrast with the background, whether positive or negative, decreases the ability of zebra finches to discriminate between target and non-target stimuli. This effect is particularly strong when colour distances are small (less than 4 ΔS) and Michelson achromatic contrast with the background is high (greater than 0.5). We suggest that researchers should consider focal colour patches and their backgrounds as collectively comprising a signal, rather than focusing on solely the focal colour patch itself.
Subject(s)
Color Perception , Finches , Animals , ColorABSTRACT
Quorum sensing in Pseudomonas aeruginosa controls the production of costly public goods such as exoproteases. This cooperative behavior is susceptible to social cheating by mutants that do not invest in the exoprotease production but assimilate the amino acids and peptides derived by the hydrolysis of proteins in the extracellular media. In sequential cultures with protein as the sole carbon source, these social cheaters are readily selected and often reach equilibrium with the exoprotease producers. Nevertheless, an excess of cheaters causes the collapse of population growth. In this work, using the reference strain PA14 and a clinical isolate from a burn patient, we demonstrate that the initial amount of public goods (exoprotease) that comes with the inoculum in each sequential culture is essential for maintaining population growth and that eliminating the exoprotease in the inoculum leads to rapid population collapse. Therefore, our results suggest that sequential washes should be combined with public good inhibitors to more effectively combat P. aeruginosa infections.
ABSTRACT
Se realizó una investigación cualitativa en el Centro Provincial de la Escuela Nacional de Salud Pública en Villa Clara, curso 2010_2011, para diseñar un plan de acciones que eleve la calidad del Diplomado de Dirección en Salud. La muestra estuvo conformada por 13 profesores del claustro, 20 cursistas y tres profesores experimentados como informantes claves. Se aplicaron encuestas, guías de observación, entrevistas y análisis de documentos, y se aplicó la técnica participativa "lluvia de ideas" a informantes claves para conocer el estado actual del funcionamiento del objeto de estudio. Se comprobó que existen dificultades que atentan contra la ejecución correcta del diplomado y se proponen acciones a partir de objetivos. La planificación, ejecución, evaluación, sistematización y socialización de ellas contribuyen a fomentar elementos medulares en la formación de los directivos del sistema, a fin de propiciar cambios organizacionales para la excelencia en la dirección de los servicios de salud.
A qualitative research work was carried out in the provincial center of the National Health School in Villaclara, in the academic course 2010-2011, to design an action plan to elevate the quality of the Health Direction Course. The sample was comprised by 13 teachers, 20 students and three experienced professors. Different techniques were applied among them we can find surveys, observation guidelines, interviews and review of documents. A brain storming technique was applied to the experienced professors to know about the functioning of the object of study. It was tested that there are difficulties that interfere in the development of the course. That´s why actions are proposed taking into account the objectives stated. The planning, execution, evaluation, systematization and socialization of these actions contribute to spread out key elements in the formation of the managers of the system, so as to apply organizational changes which contribute to excellence in the health services management.
