Abstract: Wireless-based networks encompass assisted human life in distinct domains like Agriculture, health, infrastructure, climate, transportation and defense. In particular, the wireless sensor networks have been addressed in this article. Though it has many advancements, providing secure data transmission needs a major focus on these platforms. The disruptions or interference is one of the vulnerable security problems in Wireless Sensor Networks. Inside the network, an intruder can encroach and interrupt the whole transmission process. The involvement of an intruder in the device must be remembered in the network. WSN encompasses a wide geographical region and focus on rectification of issues in protocols for routing, interoperability, connectivity, and defense plays a major role. Hence, this article addresses about routing protocols of WSN, applications, recent network security issues and their variants of defense mechanisms. The conclusion depicts the classification of network security issues, requirements, and descriptive defense mechanisms for secure data transmission.

Abstract This paper focuses on the study of the representation of the self construed as other in current Spanish poetry. Such otherness is expressed in the texts through depersonalized or dehumanized forms whose presence is perceived as a danger undermining the subject’s integrity and threatening to annihilate it. A study of otherness related to the figures of the stranger, the foreigner or the intruder is presented herein. Some sociological, philosophical or anthropological concepts expressed by authors such as Žižek, Girard, Bauman and Graham will be used for this purpose. Building on the concept of ‘inherent tension’ or ‘essential lack’, the poems account for the inner struggle of the individual in search for a solution to this crisis, in texts swinging between ascertainment, development or overcoming, and ultimately revealing that the idea of a single, consistent and steady identity is a need or desire, but it is also a utopia.

Resumen El presente artículo se centra en el estudio de las representaciones de sí mismo como otro que aparecen en la poesía española actual. Esta otredad se manifiesta en los textos mediante entidades despersonalizadas o deshumanizadas, cuya presencia es percibida como un peligro que atenta contra la integridad del sujeto y amenaza con su aniquilación. Se propone el estudio de la otredad en relación con las figuras del extraño, el extranjero o el intruso. Para ello se utilizarán conceptos expresados desde la sociología, la filosofía y la antropología por autores como Žižek, Girard, Bauman y Graham. Partiendo del concepto de tensión inherente o brecha esencial, los poemas dan cuenta de la batalla interior del individuo por solucionar esta crisis, en textos que oscilan entre su constatación, su desarrollo o su superación, revelando, finalmente, que la idea de una identidad única, coherente y estable constituye tanto una necesidad o un deseo como una utopía.

Abstract The intruder configurations (1p-1h), (2p-2h) and (3p-3h) were studied in this work for the island of inversion within the SDPF-U Hamiltonian. The effect of the proton locations on the structure (energies and transition probabilities) for even-even and even-odd magnesium (N=20-24) isotopes is studied. The unmixed intruder configurations (1p-1h), (2p-2h) and (3p-3h) in addition to the protons positions are created by restriction method. The proposed restricted configurations were applied to calculate the low-lying states and probabilities of the transitions B(E2 : 01+→ 21+) with effective charges ε p = 1.32 and ε n = 0.421 for the 32,34,36 Mg isotopes and comparing to the results of available experimental works. The good agreement between the theoretical and experimental values confirmed the existence of the intruder configurations in these nuclei. The theoretical results showed a suitable SDPF-U Hamiltonian in the calculations for the structure of the nuclei in this region. The SDPF-U results confirmed many energy states and other suggested J values.

ABSTRACT Ants present hermetism, that is, they recognize and discriminate individuals alien to the colony, even at a homospecific level, which results in aggressive reactions against intruders, varying with their age. To evaluate the importance of this factor, transfers of homospecific larvae, pupae and 2- and 8-h-old adults of Camponotus morosus Smith were carried out. All the transferred larvae developed into pupae, and later into adults, but only 20% of these survived 15 d in the receiving nests. The transferred pupae were attacked and killed in 8 d. The transfer of 2-d and 8-h old adults produced 70 and 30% acceptance, respectively. These results indicate that adults begin to develop their own odor earlier than 2-d of age. The age of the intruder was determinant in its acceptance of C. morosus homospecific resident ants, as indicated in a 1-way ANOVA (p = 0.0001). The adults that survived the transfer of larvae were later reintroduced into their original nests; 37.5% of them were accepted, compared with 65% acceptance for 2- and 8-h old adults reintroduced, indicating that there is a strong genetic influence in the development of their own smell, that would allow adults to be recognized as belonging to the nest. The fact that not all the males were accepted can be explained by the influence of the odor acquired in the receiving nest.

RESUMO Esse artigo trata da relação entre a estética e a representação na teoria de Jacques Rancière. Segundo o autor, a representação é simultaneamente presente e proibida na estética moderna. Ela aparece como um parasita ou um intruso na produção artística. Rancière pergunta: sob quais condições a representação se torna proibida e o que significa a arte não representar? O eixo central da análise explora quais as consequências dessa configuração, com destaque para a política. Segundo Rancière, o conceito de partilha do sensível implica invariavelmente um regime de vida e, portanto, alguma forma de política. Sendo assim, a estética não se limita à arte, mas atinge a vida em seu sentido pleno. A relação entre estética e representação implica necessariamente um modo de vida no qual a representação se torna impossível em todos os sentidos.

ABSTRACT This article explores the relationship between aesthetics and representation in Jacques Rancière's theory. According to the author, representation is simultaneously present and prohibited in modern aesthetics. It appears as a parasite or an intruder in artistic production. Rancière asks: under what conditions is representation prohibited and what happens when art does not represent? The central axis in the analysis explores the consequences of this configuration, with emphasis on politics. According to Rancière, the concept of distribution of the sensible invariably implies a regime of life and, therefore, some sort of politics. Hence, aesthetics is not limited to arts, reaching life as a whole. The relationship between aesthetics and representation necessarily implies a mode of life where representation becomes impossible in all senses.

RESUMO Invasão biológica é o processo no qual um organismo exótico, quando adaptado, passa a competir com as espécies nativas causando graves impactos. A espécie Cryptostegia madagascariensis Bojer ex. Decne, introduzida no Brasil com fins paisagísticos, tem se revelado uma espécie invasora bastante agressiva no bioma caatinga formando maciços autorregenerantes principalmente em áreas degradadas e às margens dos cursos de água e lagoas temporárias. Objetivou-se com este estudo avaliar aspectos reprodutivos (através da caracterização biométrica) e o potencial de emergência de plântulas de Cryptostegia madagascariensis. Para a caracterização biométrica, frutos (com coloração verde) e sementes (com coloração branca) tiveram suas dimensões mensuradas, aferindo-se ainda o número de sementes por fruto e a massa fresca de frutos e sementes. Para a avaliação da influência da posição e profundidade de semeadura na emergência de plântulas, as sementes foram semeadas em areia esterilizada com o hilo para baixo, para cima e para o lado, nas profundidades de 0,5; 1,0; 1,5; 2,0; 2,5 e 3,0 cm. A elevada produção de sementes muito leves por fruto e, por conseguinte, de sementes por indivíduo potencializa o caráter invasor de Cryptostegia madagascariensis. A emergência e o vigor de plântulas de Cryptostegia madagascariensis são reduzidos pelo aumento da profundidade.

ABSTRACT Biological invasion is the process in which an exotic organism, when adapted, shall compete with native species causing serious impacts. The species Cryptostegia madagascariensis introduced in Brazil with landscaping purposes has proved to be a very aggressive invasive species in Caatinga, forming self-regenerating masses, especially in degraded areas and on the banks of watercourses and temporary ponds. The objective of this study was to evaluate the reproductive aspects (through biometric characterization) and the potential emergence of Cryptostegia madagascariensis seedlings. To characterize biometric fruits (green colored) and seeds (white colored) had their dimensions measured by assessing whether even the number of seeds per fruit, and fresh weight of fruits and seeds. To evaluate the influence of the position and depth of sowing on seedling emergence, seeds were placed in sterile sand substrate with the hilum down, up and sideways at depths of 0.5; 1.0; 1.5; 2.0; 2.5 and 3.0 cm. The high production of very light seeds per fruit, and therefore, the seeds per individual, associated with the absence of natural enemies potentiates the intruder character of Cryptostegia madagascariensis. The emergence and vigor of Cryptostegia madagascariensis seedlings are reduced by the increase in depth.

Resumo Introdução: Comportamentos agonísticos ajudam a garantir a sobrevivência, oferecem vantagem na competição e comunicam status social. O paradigma residente-intruso, modelo animal baseado em confrontos intraespecíficos entre machos, pode ser uma ferramenta etológica relevante para investigar a neurobiologia do comportamento agressivo. Objetivos: Analisar os mecanismos comportamentais e neurobiológicos do comportamento agressivo em camundongos Swiss machos expostos a confrontos repetidos no paradigma residente-intruso. Métodos: A análise comportamental foi realizada em associação com medidas de corticosterona plasmática em camundongos expostos repetidamente a um rival em potencial próximo, porém inacessível (instigação social), ou a 10 sessões de instigação social seguidas de encontros agressivos diretos. Além disso, o fator de liberação de corticotrofina (CRF) e o fator neurotrófico derivado do cérebro (BNDF) foram medidos no encéfalo desses animais. Camundongos controles não foram expostos à instigação social ou confrontos agressivos. Resultados: Os camundongos expostos a confrontos agressivos exibiram um padrão semelhante de comportamentos agressivos e não agressivos típicos da espécie na primeira e na última sessão. Em contraste com instigação social apenas, confrontos agressivos repetidos promoveram aumento na corticosterona plasmática. Após 10 sessões de confrontos agressivos, os camundongos apresentaram uma tendência não significativa de redução dos níveis de CRF no hipocampo, que se correlacionaram inversamente com os níveis plasmáticos de corticosterona. Por outro lado, sessões repetidas de instigação social ou confronto agressivo não alteraram as concentrações de BDNF no córtex pré-frontal e hipocampo. Conclusão: A exposição a episódios repetidos de encontros agressivos não promoveu habituação ao longo do tempo. Adicionalmente, o CRF parece estar envolvido nas respostas fisiológicas aos estressores sociais.

Abstract Introduction: Agonistic behaviors help to ensure survival, provide advantage in competition, and communicate social status. The resident-intruder paradigm, an animal model based on male intraspecific confrontations, can be an ethologically relevant tool to investigate the neurobiology of aggressive behavior. Objectives: To examine behavioral and neurobiological mechanisms of aggressive behavior in male Swiss mice exposed to repeated confrontations in the resident intruder paradigm. Methods: Behavioral analysis was performed in association with measurements of plasma corticosterone of mice repeatedly exposed to a potential rival nearby, but inaccessible (social instigation), or to 10 sessions of social instigation followed by direct aggressive encounters. Moreover, corticotropin-releasing factor (CRF) and brain-derived neurotrophic factor (BNDF) were measured in the brain of these animals. Control mice were exposed to neither social instigation nor aggressive confrontations. Results: Mice exposed to aggressive confrontations exhibited a similar pattern of species-typical aggressive and non-aggressive behaviors on the first and the last session. Moreover, in contrast to social instigation only, repeated aggressive confrontations promoted an increase in plasma corticosterone. After 10 aggressive confrontation sessions, mice presented a non-significant trend toward reducing hippocampal levels of CRF, which inversely correlated with plasma corticosterone levels. Conversely, repeated sessions of social instigation or aggressive confrontation did not alter BDNF concentrations at the prefrontal cortex and hippocampus. Conclusion: Exposure to repeated episodes of aggressive encounters did not promote habituation over time. Additionally, CRF seems to be involved in physiological responses to social stressors.

ABSTRACT Hermetism, a behavior that isolates ant colonies, was studied in the laboratory between two ant species in Chile, Camponotus morosus Smith and Linepithema humile Mayr. Ants from five nests of C. morosus and L. humile were used, transferring ten individuals per nest of one of the colonies to receiving nests of the other. Conducts, including antennal exploration (AE), mandible opening (MO), dorsal flexion of the abdomen (DFA), biting (Bi), ventral flexion of the abdomen (VFA), fight (Fi), transport of the intruder ant (TI), moving backwards (MB), and death (De) were recorded during ten min, with ten replicates. The times of occurrence ± SD of each event were analyzed with the Student t test. The events AE, MO, DFA, and MB had a short latency time in receiving L. humile, while C. morosus presented lesser latency for the events Bi, VFA, and Fi. When analyzing by χ2 the frequency of occurrence of each event per species, AE and MO were similar in both species, and in aggression and rejection events like DFA, Bi, VFA, Fi, MB, TI, and De, there were greater frequencies of observations in C. morosus that in L. humile. From these results, C. morosus is a more hermetic ant than L. humile.

RESUMEN Se estudió en laboratorio el hermetismo, un comportamiento de aislación entre colonias entre dos especies de hormigas en Chile, Camponotus morosus Smith y Linepithema humile Mayr. Se utilizaron hormigas desde cinco nidos de C. morosus y L. humile, y se transfirieron diez individuos por nido desde una de las colonias hacia nidos receptores de la otra. Las conductas se grabaron durante 10 min, incluyendo exploración con las antenas (EA), abertura mandibular (AM), flexión dorsal del abdomen (FDA), mordedura (Mo), flexión ventral of del abdomen (FVA), vuelo (Vu), transporte de la hormiga intrusa (TI), retroceso (Re) y muerte (Mu), con diez repeticiones El tiempo de desarrollo ± DS de cada evento se analizó con el test t de Student. Los eventos EA, AM, FDA y Re tuvieron un tiempo de latencia corto al recibir a L. humile, mientras que C. morosus presentó menor latencia en los eventos Mo, FVA y Vu. Al analizar mediante χ2 la frecuencia de ocurrencia de cada evento, EA y AM fueron similares en ambas especies, y en los evento de agresión y rechazo como FDA, Mo, FVA, Vu, Re, TI y Mu hubo mayor frecuencia de observaciones en C. morosus que en L. humile. Con estos resultados, C. morosus es una hormiga más hermética que L. humile.

The exorcism is a well-knownpractice since the origins of Christianity. It lies in facing the hostile presence of a spirit in the body of the faithful. The specialist's intervention has the objective of chasing out the intruder spirit. In catholic contexts, the priest has the monopoly of this ritual. However, a group often supports the exorcist. Seen as a legitimate demand for some Church members, and an expression of psychiatric illness by others, the practice of the exorcism has found a way to grow in some parishes in Buenos Aires' suburbs. I will expose here the development and results of a qualitative research accomplished in Buenos Aires between 2013 and 2015. I've worked with three groups created by catholic priests that carry out, every week, rituals of exorcism. The possession, and the subsequent ritual of exorcism, lack of a cinematographic make in scene. The participants understand both possession and expulsion as a process related to health, healing and liberation, and the practices are lined up with the quest of wellbeing. The possession and the ways of facing this symptom express some unspecific discomfort which form is being constituted in the ritual sociability.

El exorcismo es una práctica conocida desde los orígenes del cristianismo. Se trata de hacer frente a una presencia demoníaca en el cuerpo del fiel. La intervención del especialista tiene el objetivo de expulsar el demonio invasor. En contextos católicos, el sacerdote tiene el monopolio del ritual, aunque a menudo un grupo de asistentes ayuda al exorcista. Pensado como una demanda legítima por algunos miembros de la Iglesia, como una expresión de trastornos psiquiátricos por otros, la práctica del exorcismo crece en ciertas parroquias de Buenos Aires y sus periferias. En este artículo expondré los resultados de una investigación cualitativa llevada a cabo entre 2013 y 2015. Trabajé con tres grupos organizados por sacerdotes católicos que realizan, cada semana, rituales de exorcismo. La posesión y el ritual de exorcismo, se alejan de la puesta en escena cinematográfica. Los participantes los comprenden como un proceso relacionado con la salud, la sanación y la liberación, y las prácticas son interpretadas en términos de búsqueda de bienestar. La posesión/ obsesión y las maneras de enfrentar la serie de síntomas relacionados con ellas, expresan malestares difusos que encuentran en estas prácticas un lenguaje para traducirlas.

Resumen Este artículo analiza el significado de la figura del poeta como "intruso" en la obra de Stéphane Mallarmé, tal como es estudiada por el filósofo y ensayista francés Jacques Rancière en La política de la sirena y La palabra muda. Nuestra intención apunta a mostrar otras definiciones del rol del poeta y del espacio literario en uno de los creadores más destacados del arte contemporáneo.

Abstract This essay analyzes the meaning of the figure of the poet as intruder in Stéphane Mallarmé's works, as it is studied by the French critical theorist and philosopher Jacques Rancière in Politics of the Siren and Mute speech. Our intention is to reflect about and expand definitions of the role of the poet and the literary space in one of the most remarkable creators of contemporary art.

Résumé Cet article analyse la figure du poète comme « intrus » dans l'œuvre de Stéphane Mallarmé, telle qu'elle est étudiée par le philosophe et essayiste français Jacques Rancière dans « La politique de la sirène » et « La parole muette ». Nous voulons montrer autres définitions du rôle du poète et de l'espace littéraire chez un des créateurs le plus importants de l'art contemporain.

Intruders detection in computer networks has some deficiencies from machine learning approach, given by the nature of the application. The principal problem is the modest display of detection systems based on learning algorithms under the constraints imposed by real environments. This article focuses on the machine learning approach for network intrusion detection in batch and data stream environments. First, we propose and describe three variants of KDD99 dataset pre processing including attribute selection. Secondly, a thoroughly experimentation is performed from evaluating and comparing representative batch learning algorithms on the variants obtained from KDD99 pre processing. Finally, since network traffic is a constant data stream, which can present concept drifting with high rate of false positive, along with the fact that there are not many researches addressing intrusion detection on streaming environments, lead us to make a comparison of various representative data stream classification algorithms. This research allows determining the algorithms that better perform on the proposed variants of KDD99 for both batch and data stream environments.

La detección de intrusos en redes de computadoras a partir del enfoque de aprendizaje automático presenta algunas deficiencias dadas por la propia naturaleza de la aplicación. La principal viene dada por el modesto despliegue de sistemas de detección basados en algoritmos de aprendizaje bajo las restricciones impuestas por los entornos reales. En este artículo se describen y proponen tres variantes de pre procesamiento sobre el conjunto de datos KDD99, incluye selección de atributos. Luego la experimentación se realiza primeramente a partir de evaluar algoritmos representativos en entornos estacionarios sobre las variantes obtenidas a partir de pre procesar KDD99. Por último, dado que el tráfico de red es un flujo constante de datos, en el cual pueden existir variaciones de conceptos relacionadas con las tasas de falsos positivos, unido al hecho de que no se encuentran muchas investigaciones que aborden la detección de intrusos en entornos de flujos de datos nos conduce a realizar una comparación de varios algoritmos también representativos de flujos de datos. Como resultado se obtiene cuáles son los algoritmos que mejores resultados ofrecen en la detección de intrusos sobre las variantes de pre procesamiento propuestas, tanto para entornos estacionarios como de flujos de datos.

Objetivo: Investigar os efeitos da exposição ao etanol em ratos adolescentes durante a idade adulta sobre os comportamentos agressivos e semelhantes à ansiedade, bem como sobre as medidas de níveis de marcadores inflamatórios.Métodos:Os grupos de ratos Wistar machos (peso médio de 81,4 g; n = 36) foram alojados em grupos de quatro até o dia pós-natal (DPN) 60. Entre os DPNs 30 e 46, os ratos receberam um dos três tratamentos: 3 g/kg de etanol (15% w/v, oralmente, n = 16), 1.5 g/kg de etanol (12,5% w/v, oralmente, n = 12), ou água (n = 12) a cada 48 horas. Os comportamentos agressivos (teste residente-intruso) e semelhantes à ansiedade (labirinto em cruz elevado) foram avaliados durante a idade adulta dos animais.Resultados:Os animais que receberam doses menores de álcool mostraram níveis reduzidos de fator neurotrófico derivado do cérebro (BDNF) no hipocampo quando comparados ao grupo controle. Nenhuma diferença significativa foi verificada no córtex pré-frontal.Conclusões:A exposição intermitente ao álcool durante a adolescência é associada com menores níveis de BDNF no hipocampo, provavelmente divido a administração episódica de álcool, mas o uso não alterou o nível de agressão contra o macho intruso ou os comportamentos semelhantes à ansiedade durante a fase adulta.

Objective:To investigate the effects of ethanol exposure in adolescent rats during adulthood by assesssing aggression and anxiety-like behaviors and measuring the levels of inflammatory markers.Methods:Groups of male Wistar rats (mean weight 81.4 g, n = 36) were housed in groups of four until postnatal day (PND) 60. From PNDs 30 to 46, rats received one of three treatments: 3 g/kg of ethanol (15% w/v, orally, n = 16), 1.5 g/kg of ethanol (12.5% w/v, PO, n = 12), or water (n = 12) every 48 hours. Animals were assessed for aggressive behavior (resident x intruder test) and anxiety-like behaviors (elevated plus maze) during adulthood.Results:Animals that received low doses of alcohol showed reduced levels of brain-derived neurotrophic factor (BDNF) in the hippocampus as compared to the control group. No significant difference was found in prefrontal cortex.Conclusions:Intermittent exposure to alcohol during adolescence is associated with lower levels of BDNF in the hippocampus, probably due the episodic administration of alcohol, but alcohol use did not alter the level agression toward a male intruder or anxiety-like behaviors during the adult phase.

Con el presente artículo de reflexión se pretende exponer teóricamente que el fenómeno del activismo judicial desdibuja los límites competenciales del ejercicio de los poderes públicos a favor del juzgador, lo que dependiendo de la óptica de equilibrador o intruso, se puede ver como legítimo o ilegítimo. Asimismo, se sustentará en qué circunstancias un juez crea derecho, asumiendo la condición de legislador positivo, también se ilustrará cuándo actúa como legislador negativo y bajo qué presupuesto como juez-administrador. Finalmente se sostendrá que el sistema actual de frenos y contrapesos en Colombia adolece de un desequilibrio o desbalance provechoso para la judicatura.

With the present paper is to explain theoretically the phenomenon of judicial activism blurs the jurisdictional limits of the exercise of public powers in favor of the judge, so depending on the perspective of balancing or intruder can be seen as legitimate or illegitimate. Also, it will be supported under what circumstances ajudge creates law, taking the form of positive legislator, also will illustrate when acting as negative legislator and under what budget as judge-administrator. Finally, we argue the present system of checks and balances in Colombia suffers from an imbalance profitable for the judiciary.

It is well known that the most evident differences in humans are those related to anthropometric characteristics, and that during continuous monitoring the relation between human behavior and human abilities concerning their anthropometric characteristics was observed. The aim of this study was to detect and define the morphological types with the use of slightly different and more advanced methodologies. The sample included 149 male subjects, first-year students of the Faculty of Sport and Physical Education in Novi Sad, using an anthropometric measurement technique. A total of 12 anthropometric measures, defined according to the four-dimensional morphological model was used. For all variables, basic descriptive statistics were calculated while student grouping was performed using taxonomic neural network Intruder. Initial taxonomic classification of artificial entities by neural network Intruder accepted four clusters: endomorph or pyknic, ectomorph or leptosomic, astenomorph and gracile type. The results indicate that the identification and definition of morphological types with the use of a slightly different and more advanced procedure leads to better and earlier perception of certain characteristics which are necessary, both for the selection of specific sports, and in the prevention of various diseases and abnormalities in behavior and functioning.

Es bien sabido que las diferencias más evidentes en los seres humanos son aquellas relacionadas con las características antropométricas, lo cual fue observado durante el monitoreo continuo de la relación entre el comportamiento humano y las capacidades humanas. El objetivo de este estudio fue detectar y definir los tipos morfológicos con el uso de metodologías diferentes y más avanzadas. La muestra incluyó 149 sujetos hombres, estudiantes de primer año de la Facultad de Educación Física y Deportiva en Novi Sad, utilizando una técnica de medición antropométrica. Utilizamos un total de 12 medidas antropométricas, que se definieron de acuerdo con el modelo morfológico de cuatro dimensiones. Para todas las variables se calcularon los estadísticos descriptivos básicos, mientras que la agrupación estudiantil se realizó a través de red neuronal - Intruder. Para la clasificación taxonómica inicial de entidades artificiales por red neuronal Intruder se aceptaron cuatro grupos: endomorfo o pícnico, ectomorfo o leptosomo, astenomorfo y tipo grácil. Los resultados indican que la identificación y definición de los tipos morfológicos con el uso de un procedimiento algo diferente y más avanzado conduce a una mejor percepción de ciertas características que son necesarias, tanto para la selección de deportes específicos, como para la prevención de diversas enfermedades y alteraciones en el comportamiento y funcionamiento.

A tryptophan diet reduces aggressive behavior in different species, although some controversial findings have been reported. We studied 65 male mice divided into four groups according to increasing dosages of tryptophan (10, 20, 30, and 100 mg/kg) and a control group (vehicle). The first four groups ingested 10, 20, 30, and 100 mg/kg tryptophan together with cellulose vehicle and water by gavage before the behavioral tests that sought to record aggressive behavior. The control group received only the vehicle at the same time that the other groups received the tryptophan solutions. The results showed that low concentrations (10 and 20 mg/kg) of tryptophan decreased (p < .04) the frequency of attack bites and lateral threats (i.e., aggressive components; p < .02) after an encounter with a male intruder without altering locomotor activity. In conclusion, the low concentrations of tryptophan diminished aggressive behavior against a male intruder.