975 resultados para SOCIAL HIERARCHY


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Seven colonies of Mischocyttarus cassununga were studied under field conditions at Universidade Federal de Juiz de Fora, MG, in southeastern Brazil: in pre-emergence, post-emergence and decline stages, during 145.8 hours. Dominance interactions among the females were quantified to verify the dynamics of succession in the social hierarchy of the colonies. Early pre-emergence colonies present more intense aggressive interactions than late pre-emergence ones, because the females are engaged in securing the role of main egg layer in the nest. In post-emergence (pre-male) colonies the dominance hierarchy is more defined and the frequency of dominance and subordination behaviors were lower than in pre-emergence stages: most of the agonistic behaviors are restricted to the first ranked females (potentially queens) and the subordinate individuals play the role of workers in the nests. In the post-emergence, post-male, and decline stages the hierarchy is still maintained by the aggressive behaviors of the 1st-ranked female but because the presence of males and future nest foundresses these interactions are not well defined in a linear way.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Aquaculture practices usually put the Nile tilapia in an artificial social environment, which males predominate due to their faster growth desirable for aquaculture purposes. Such a situation can increase male-male fighting because males are generally more aggressive than females, and also because fighting ability is similar within the same sex, leading to longer contests. As behavior has been used to infer welfare in several fish species, the aim of this study was to investigate whether sex composition affects agonistic interactions, social hierarchy and energetic demand in groups of Nile tilapia (Oreochromis niloticus; L.). Size-matched adult fish were divided in two treatments: MM = four males and MF = two males and two females (10 repetitions for each treatment). The experiment lasted for 11 days and social interactions (aggressiveness and rank order) were recorded at the 2nd, 6th and 10th days (15 min per day). Fish were food deprived and body weight loss was used to infer energetic cost. A higher frequency of lateral threat (Student’s t independent test; t = 2.55; p = 0.02) and total interactions (Student’s t independent test; t = -2.81; p = 0.01) was observed in the MF treatment. MM group showed unstable hierarchy (Binomial test, p = 0.04), which is considered a social stressor. However, mean weight loss was not affected by treatments (Student’s t independent test; t = -0.74; p = 0.47). These results support the idea that sexual composition affects aggressive interactions and destabilizes social hierarchy, but not energy cost

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In spite of the high prevalence and negative impact of depression, little is known about its pathophysiology. Basic research on depression needs new animal models in order to increase knowledge of the disease and search for new therapies. The work presented here aims to provide a neurobiologically validated model for investigating the relationships among sickness behavior, antidepressants treatment, and social dominance behavior. For this purpose, dominant individuals from dyads of male Swiss mice were treated with the bacterial endotoxin lipopolysaccharide (LPS) to induce social hierarchy destabilization. Two groups were treated with the antidepressants imipramine and fluoxetine prior to LPS administration. In these groups, antidepressant treatment prevented the occurrence of social destabilization. These results indicate that this model could be useful in providing new insights into the understanding of the brain systems involved in depression.

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In this work we characterized the social hierarchy of non-reproductive individuals of Cichlasoma dimerus (Heckel, 1840). independently for both sexes, and its relationship to the opportunity for social status ascent. Female and male individuals who were located on the top rank of the social hierarchy, ascended in social status when the opportunity arose, therefore indicating that dominance is directly correlated with social ascent likelihood. Dominance was positively correlated with size in males but not in females, suggesting for the latter a relationship with intrinsic features such as aggressiveness or personality rather than to body and/or ovarian size. Physiological and morphometrical variables related to reproduction, stress and body color were measured in non-reproductive fish and correlated with dominance and social ascent likelihood. Dominance was negatively correlated with plasma cortisol levels for both sexes. No correlation with dominance was found for androgen plasma levels (testosterone and 11-ketotestosterone). No correlation was detected between dominance and the selected morphological and physiological variables measured in females, suggesting no reproductive inhibition in this sex at a physiological level and that all females seem to be ready for reproduction. In contrast, social hierarchy of non-reproductive males was found to be positively correlated with follicle stimulating hormone (FSH) pituitary content levels and gonadosomatic indexes. This suggests an adaptive mechanism of non reproductive males, adjusting their reproductive investment in relation to their likelihood for social status ascent, as perceived by their position in the social hierarchy. This likelihood is translated into a physiological signal through plasma cortisol levels that inhibit gonad investment through pituitary inhibition of FSH, representing an anticipatory response to the opportunity for social status ascent. (C) 2012 Elsevier Inc. All rights reserved.

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El objetivo de esta Tesis doctoral es arrojar más luz sobre los mecanismos a partir de los cuales se dibuja el mapa de la desigualdad social en los sistemas urbanos contemporáneos. Para ello, en primer lugar se ha realizado una revisión crítica de los diferentes planteamientos desde los que se abordan los procesos de formación del espacio social urbano. A partir de ahí se ha aplicado el campo teórico analizado a un caso concreto muy representativo, el espacio social del Madrid de finales del siglo XX, comprobándose cómo los planteamientos tradicionales muestran carencias en cuanto a la explicación de los procesos estudiados. Por otro lado, una vez constatado que el espacio social madrileño producto del régimen de acumulación fordista destaca por un dibujo especialmente clasificado y jerarquizado, se ha analizado cuando y por qué comenzó este fenómeno de tan radical "clasificación social". Como resultado se obtiene que sólo es posible generar un discurso de explicación del espacio social estudiado considerando, por un lado, la percepción de la ciudad preexistente y, por otro, la concepción y construcción de la “planeada” por un modelo inmobiliario obligado a reconstruir en su mapa de precios una estructura social recién transformada. Una vez comprobado que la transformación que sufrieron tanto la estructura social como el modelo inmobiliario supuso un cambio de fase en la evolución de la ciudad y su espacio social se ha formulado un nuevo modelo urbano que se ha denominado “Ciudad Negocio” . En esta Ciudad Negocio destaca un modelo inmobiliario de venta de viviendas financiadas que, debido a sus propios mecanismos de funcionamiento, requiere de un espacio social muy ordenado, jerarquizado y estable que reproduzca la estructura social existente de forma visible. ABSTRACT The aim of this research project is to shed more light on the variables that draw the social inequality maps in the contemporary urban systems. For that purpose, a thoughtful review of the different theories around urban and social planning has taken place. The outcome of the analysis has been projected over a very representative sample, the social space in Madrid at the end of the 20th Century, proving the fact that traditional arguments do not explain the way the contemporary social patterns has been developed. On the other hand, once verified the fact that the social space in Madrid conceptually inherited from the Regulation School outlines a social hierarchy pattern, an analysis of the reasons that lead to such “social classification” has been performed. The research conclusions around the reviewed urban space can only be sustained by the perception of a pre-existing city and the boundaries of a real state pattern forced to match the prices to the newly transformed social structure. The transformation of the social structure and the real state model and its impact over the urban space has lead to a new urban model called “Business City”. This new urban product is built over a residential real estate market, which in nature requires of a very organised, socially classified and stabled pattern so that it mirrors the existing social structure.

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Psychological stress is thought to contribute to reactivation of latent herpes simplex virus (HSV). Although several animal models have been developed in an effort to reproduce different pathogenic aspects of HSV keratitis or labialis, until now, no good animal model existed in which application of a psychological laboratory stressor results in reliable reactivation of the virus. Reported herein, disruption of the social hierarchy within colonies of mice increased aggression among cohorts, activated the hypothalamic-pituitary-adrenal axis, and caused reactivation of latent HSV type 1 in greater than 40% of latently infected animals. However, activation of the hypothalamic-pituitary-adrenal axis using restraint stress did not activate the latent virus. Thus, the use of social stress in mice provides a good model in which to investigate the neuroendocrine mechanisms that underlie behaviorally mediated reactivation of latent herpesviruses.

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Thesis (Master's)--University of Washington, 2016-06

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Abstract This dissertation explores damaging tendencies that exist within autonomy-oriented activism in the West. I examine how affect shapes the way that internal conflict is approached and internal strife is dealt with in radical communities. I adopt Sara Ahmed’s proposition “that our emotions are bound up with the securing of the social hierarchy” (Ahmed, 2004b: 4) and given that autonomy-oriented practices are committed to dismantling existing hierarchies, it follows that the less oppressive social configurations sought by autonomous social movements must have different emotional underpinnings. My thesis involves applying critical theory on affect and emotion in social movements to interview data gathered from activists both currently and historically involved in autonomy-oriented social movement communities in Kingston, Ontario. I ask whether anglophone, western-based, autonomy-oriented social movements reproduced understandings of affect/emotions/feelings that underwrite the social order they are working against? I also ask, “how are our emotions conditioned by capitalism?”. The research that I engage with provides responses to these questions by pointing out how the dominant discourse on emotions in the West encourages and informs certain modes of identity production that affect the diminishing and sad practices of autonomy-oriented communities and the (re)production of oppressive practices found in the dominant order. My work critically places this psychologizing view of emotions, and its damaging effects on resistance, within the context of neoliberal capitalism. I argue that the way we understand the politics of affect is an important dimension of radical struggle, and will inform and impact upon our individual and collective capacities to respond to, and refuse to reproduce relations of control and domination. I look for an understanding of “why” and to “what extent” these determinations exists, and look for hope in a politics of affect which supports an autonomy-oriented ethic.

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This work studies the creation, development and evolution of the Spanish midshipmen, through their requirements, from the early 18th century to the second third of the 19th century. The aims are: to know deeply an essential post in the Navy –naval cadet- that still requires an exhaustive review; and, primarily, to link the transformations of the candidates’ requirements to the social debates which were proposed in Spain during this two centuries. The so-called transition from the estates society to the class society, or the step from a society of inheriting criteria to a society based on achieving variables, did not occur linearly; changes and inertia went hand in hand with contradictions and conflicts, thus in this paper the Spanish midshipmen are analysed by several relationally variables.

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The effect of salinity (0, lO and 20%o, water temperature 28 ± l oC) on food consumption and growth of juvenile Nile tilapia, Oreochromis niloticus L. (9.94 ± 0.15 g) were investigated by feeding group of 20 fish at 2% body weight day. Individual food consumption was measured using X-radiography. There were no significant differences in growth or white muscle protein concentrations among groups. During feed deprivation, weight loss was similar for fish held at O%o and 10 %o salinity, but after 7 days over 50% of the fish maintained at 20%o salinity developed lesions covering 5-25% of the body. No significant relationships were observed between individual specific growth rates and food consumption rates within the groups. The fish in all salinity groups showed a negative correlation between specific growth rate and food conversion ratio. The coefficient of variation for wet weight specific food consumption and the mean share of meal for each fish were used as a measure of social hierarchy strength. A negative correlation was observed between coefficient of variation in food consumption and mean share of meal. The social hierarchy structure was similar in all salinities; 25% of the fish were dominant (18.29% above an equal share of meal) and 30% were subordinate (16.19% below an equal share of meal) and the remainder 45% fish fed theoretical share of meal (MSM, 5.26%).

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Abstract In species with social hierarchies, the death of dominant individuals typically upheaves the social hierarchy and provides an opportunity for subordinate individuals to become reproductives. Such a phenomenon occurs in the monogyne form of the fire ant, Solenopsis invicta, where colonies typically contain a single wingless reproductive queen, thousands of workers and hundreds of winged nonreproductive virgin queens. Upon the death of the mother queen, many virgin queens shed their wings and initiate reproductive development instead of departing on a mating flight. Workers progressively execute almost all of them over the following weeks. To identify the molecular changes that occur in virgin queens as they perceive the loss of their mother queen and begin to compete for reproductive dominance, we collected virgin queens before the loss of their mother queen, 6 h after orphaning and 24 h after orphaning. Their RNA was extracted and hybridized against microarrays to examine the expression levels of approximately 10 000 genes. We identified 297 genes that were consistently differentially expressed after orphaning. These include genes that are putatively involved in the signalling and onset of reproductive development, as well as genes underlying major physiological changes in the young queens.