Antonio Pires de Camargo

Lack of spatial segregation in the representation of pheromones and kairomones in the mouse medial amygdala

The nervous system is organized to detect, internally represent and process sensory information to generate appropriate behaviors. Despite the crucial importance of odors that elicit instinctive behaviors, such as pheromones and kairomones, their neural representation remains little characterized in the mammalian brain. Here we used expression of the immediate early gene product c-Fos as a marker of neuronal activity to find that a wide range of pheromones and kairomones produces activation in the medial nucleus of the amygdala, a brain area anatomically connected with the olfactory sensory organs. We see that activity in this nucleus depends on vomeronasal organ input, and that distinct vomeronasal stimuli activate a dispersed ensemble of cells, without any apparent spatial segregation. This activity pattern does not reflect the chemical category of the stimuli, their valence or the induced behaviors. These findings will help build a complete understanding of how odor information is processed in the brain to generate instinctive behaviors.

Methodology to Evaluate Dripper Sensitivity to Clogging due to Solid Particles: An Assessment

Emitter clogging is a major problem in microirrigation systems, which may result from the isolated or combined effects of physical, chemical, and biological agents. Clogging caused by suspended solid particles is the most common plugging form of emitters. Water quality and emitter geometry are key aspects in clogging processes. Any suitable test procedure to assess the sensitivity of drippers to clogging should take into account the predominant factors that influence clogging and must reproduce the field conditions. This research set out to assess the performance and suitability of a laboratory clogging test procedure in order to validate a methodology and to provide scientific results that may support the standardization of a clogging test method. The evaluated methodology has been used by the IRSTEA laboratory since 1974 (Platform of Research and experiment on Science and Technology for Irrigation - PReSTI, formerly LERMI) and its contents are currently being discussed by the ISO TC23/SC18 committee. The aim is to define a standardized testing protocol to evaluate the sensitivity of emitters to clogging due to solid particles. Replications analyzing the clogging resistance of four models of emitting pipes were carried out in a laboratory. The clogging test procedure enabled an accurate assessment of the combinations of concentration and size of particles that caused clogging in each model of dripper. However, a significant variability in degree of clogging was identified when the results of replications for each model of dripper were compared. Several requirements, concerns, and improvements related to the clogging test protocol were discussed.

Behavioral Assays in the Study of Olfaction: A Practical Guide

Olfaction is a fundamental sense in most animal species. In mammals, the olfactory system comprises several subpopulations of sensory neurons located throughout the nasal cavity, which detect a variety of chemostimuli, including odorants, intraspecies and interspecies chemical communication cues. Some of these compounds are important for regulating innate and learned behaviors, and endocrine changes in response to other animals in the environment. With a particular focus on laboratory rodent species, this chapter provides a comprehensive description of the most important behavioral assays used for studying the olfactory system, and is meant to be a practical guide for those who study olfaction-mediated behaviors or who have an interest in deciphering the molecular, cellular, or neural mechanisms through which the sense of smell controls the generation of adaptive behavioral outputs.

Avaliação de método para determinação da sensibilidade de gotejadores à obstrução por partículas sólidas

RESUMO: A obstrução de emissores tem sido considerada como um dos principais problemas do sistema de irrigação por gotejamento. Por isso, um projeto de norma tem sido proposto para avaliação da sensibilidade de emissores sob condição de risco de obstrução. O método tem como base um procedimento desenvolvido e utilizado por um laboratório da França. Objetivouse, neste trabalho, realizar um estudo para avaliar o protocolo de ensaios utilizado como base para a norma. Foram realizados três ensaios, considerados como repetições, utilizando quatro modelos de tubogotejadores comerciais, utilizando material de obstrução originado de solo natural. O ensaio foi divido em quatro fases, utilizando concentrações de 125, 250, 375 e 500 mg L e faixas granulométricas de < 75, 75-125, 125-212, 212-500 μm para as fases um, dois, três e quatro, respectivamente. Embora a obstrução dos modelos de gotejadores avaliados tenha ocorrido sempre em uma determinada fase, foi observado variações dos resultados de grau de obstrução entre repetições. Considera-se que o procedimento de ensaio deve ser aprimorado a fim de reduzir a variabilidade dos resultados de ensaio e tornar o procedimento de ensaios mais adequado.