921 resultados para Territory monopolization
Effects of territorial intrusions on eavesdropping neighbors: communication networks in nightingales
Resumo:
Animal communication often occurs in communication networks in which multiple signalers and receivers are within signaling range of each other. In such networks, individuals can obtain information on the quality and motivation of territorial neighbors by eavesdropping on their signaling interactions. In songbirds, extracting information from interactions involving neighbors is thought to be an important factor in the evolution of strategies of territory defense. In a playback experiment with radio-tagged nightingales Luscinia megarhynchos we here demonstrate that territorial males use their familiar neighbors' performance in a vocal interaction with an unfamiliar intruder as a standard for their own response. Males were attracted by a vocal interaction between their neighbor and a simulated stranger and intruded into the neighbor's territory. The more intensely the neighbor had interacted with playback, the earlier the intrusions were made, indicating that males eavesdropped on the vocal contest involving a neighbor. However, males never intruded when we had simulated by a second playback that the intruder had retreated and sang outside the neighbor's territory. These results suggest that territorial males use their neighbors' singing behavior as an early warning system when territorial integrity is threatened. Simultaneous responses by neighboring males towards unfamiliar rivals are likely to be beneficial to the individuals in maintaining territorial integrity.
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In male birds, the gonadal hormone testosterone (T) is known to influence territorial and mating behaviour. Plasma levels of T show seasonal fluctuations which vary in relation to mating system and social instability. First, we determined the natural T profile of male blue tits Parus caeruleus during the breeding season. We found that plasma levels of T increased at the onset of nest building. Thus, the increase in circulating T was not associated with territory establishment, nor with the fertile period of the males' mates. In most individuals, T levels dropped to values close to zero during the period of chick feeding. Second, we investigated the relationship between plasma levels of T and male age, size, and singing behaviour. During the mating period, T levels did not differ between 1 yr old and older males and did not correlate with body size or condition. However, song output during the dawn chorus tended to be positively correlated with T levels. Therefore, if high T levels are costly, song output might be an honest indicator of male quality in blue tits. Finally, we show that plasma levels of T are significantly higher during the night than during the day. This pattern has also been observed in captive non-passerine birds, but its functional significance remains unknown.
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This article looks at the difference between scientists’ written reports and their oral accounts, explanations and stories. The subject of these discourses is the eruption of Mount Chance on Montserrat, a British Overseas Territory in the Eastern Caribbean, and its continued monitoring and reporting. Scientific notions of risk and uncertainty which feature in these texts and tales will subsequently be examined and critiqued. Further to this, this article will end by pointing out that, ironically, the latter - the tale – can in some cases be a more effective and approximate mode of communication with the public than the former – the text.
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In this article we think about the need to generate spaces of meeting between museum educators and teachers. We analyze the results of different works elaborated by the research group Art and Education, basically in the report of the project maestrosymuseos.com. Red Iberoamericana de educación en museos (AECID A/8780/07), as well as the offers that we have developed. We appear how we see the teachers in his visits, and how they would like to be seen when they submerge in the territory of the museum. We introduce the supposition that the majority of teachers turn into invisible figures on having come to the museum. The methodology is based on the case studies, affecting in the observation, the interviews, and very special in the specific attention towards the protagonists: the teachers. The work introduces photos that they try to investigate in the same aspects that the article text treats, but enriching it with images that can be read in his format and with particular intentions.
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A new kind of photographic representation, called movement-image is proposed and discussed to record the visual experience of the journey through urban highways. It consists of performing long exposure photographic shots while the track is traversed, thus registering a time-panorama which includes landscape signs and inner spaces of the ways involved. This proposal is linked to the limitations of representing these expressways, if they are understood as structures of instrumental origin, where the resulting experience comes from moving at high speed through the territory. In al almost all cases the aesthetic approach or urban integration with the city and landscape are excluded. In this sense, although such structures may be an opportunity to collect, build and colonize the urban landscape, the lack of adequate representation of the phenomenon causes a difficulty in its understanding and transformation. The options for representation using photography is assumed, knowing its own particular tradition in the use of long exposures, for the expression of the mobile, and the multiple visual attention, divided or weakened.
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La gráfica se encuentra en un proceso de simbiosis con la cultura visual en el que la tecnología de la imagen, la descentralización de la matriz y la adaptación del formato expositivo se funden con el resto de las actividades artísticas. El análisis de las comunidades formadas alrededor de esta práctica configura un puzzle, aparentemente bien encajado, que se divide entre el formalismo y el conceptualismo y entre la idea y el proceso. Las bienales y trienales, a la vanguardia del discurso, cuestionan cualquier concepto que se haya podido asentar con solidez: ante la decadencia del proceso artesanal el mensaje se profundiza nutriéndose de la invectiva provocada por las contradicciones sociales, territoriales y medioambientales para convertirse en un reflejo de la sociedad contemporánea. Comprender la gráfica actual pasa por un ejercicio de aperturismo y un proceso de adaptación al cambio técnico e iconográfico de los sectores implicados. El grabado es ahora un territorio en el que la integración de todas las artes permite cruzar sus fronteras con fluidez.
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The global increase in the penetration of renewable energy is pushing electrical power systems into uncharted territory, especially in terms of transient and dynamic stability. In particular, the greater penetration of wind generation in European power networks is, at times, displacing a significant capacity of conventional synchronous generation with fixed-speed induction generation and now more commonly, doubly fed induction generators. The impact of such changes in the generation mix requires careful monitoring to assess the impact on transient and dynamic stability. This study presents a measurement-based method for the early detection of power system oscillations, with consideration of mode damping, in order to raise alarms and develop strategies to actively improve power system dynamic stability and security. A method is developed based on wavelet-based support vector data description (SVDD) to detect oscillation modes in wind farm output power, which may excite dynamic instabilities in the wider system. The wavelet transform is used as a filter to identify oscillations in frequency bands, whereas the SVDD method is used to extract dominant features from different scales and generate an assessment boundary according to the extracted features. Poorly damped oscillations of a large magnitude, or that are resonant, can be alarmed to the system operator, to reduce the risk of system instability. The proposed method is exemplified using measured data from a chosen wind farm site.
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This paper looks at urban regeneration in Belfast as a stage on which the interaction between different structural dynamics (political, economic and cultural) is manifested in the city. It discusses how contested ideas of ‘space’, ‘place’ and ‘territory’ frame the ways in which Belfast has changed over recent years and asks if regeneration itself has the potential to transform the dynamic of deep-rooted ethno-national divisions. The research question is explored through a case study of proposed urban regeneration in north Belfast. It is found that, while there is evidence of transition to less exclusivistic attitudes in leisure and work spaces, asymmetrical conflict over residential space persists in ways which reproduce deep-rooted political and cultural patterns of territorial fixity and division.
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Student units or the group-based field education and supervision of social work students offer many advantages as an efficient field placement model as well as opportunities for students to learn from each other through sharing knowledge, working collaboratively, hearing different perspectives and discussing issues. Despite the enormous potential of student units, they are a largely uncharted territory. There is a scarcity of literature on the topic and very few guidelines as to the provision of student units. The term student unit covers a broad range of student group learning opportunities and activities. This study explores this model of social work field education and its implications for student field work learning in a group context. The discussion is based on a review of the experiences, opinions and impressions of participants of an actual university based social work student unit.
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The aim of this article is to explore the recent Bill of Rights debate in the UK. This is deliberately located in the UK’s complex ‘national question’ because of the obsessive focus on achieving a proper grounding for human rights. A new form of national human rights protectionism appears to be emerging and merits careful consideration. The article suggests that it is better to acknowledge and accept the existence of a plurality of nationalisms in the UK in these discussions and understand how an essentially ‘British nationalist’ discourse sounds and works in that overall context. The concern is that the Bill of Rights debate is becoming an inadequate surrogate for the more challenging constitutional conversations that are required, and human rights discourse thus invested with expectations of national renewal that it can never meet and does not have the internal resources to resolve. If the process does go forward it may be better to prepare the ground for a deeper and wider constitutional dialogue across these islands than stumble clumsily and divisively into this territory simply via ‘another’ UK Bill of Rights.
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Introduction: The laboratory mouse is a powerful tool in cardiovascular research. In this report, we describe a method for a reproducible mouse myocardial infarction model that would allow subsequent comparative and quantitative studies on molecular and pathophysiological variables. Methods: (A) The distribution of the major coronary arteries including the septal artery in the left ventricle of the C57BL/6J mice (n=20) was mapped by perfusion of latex dye or fluorescent beads through the aorta. (B) The territory of myocardial infarction after the ligation of the most proximal aspect of the left anterior descending (LAD) coronary artery was quantified. (C) The consistency in the histological changes parallel to the infarction at different time points was analyzed. Results: (A) The coronary artery tree of the mouse is different from human and, particularly, in regard to the blood supply of the septum. (B) Contrary to previous belief, the septal coronary artery in the mouse is variable in origin. (C) A constant ligation of the LAD immediately below the left auricular level ensures a statistically significant reproducible infarct size. (D) The ischemic changes can be monitored at a histological level in a way similar to what is described in the human. Conclusion: We illustrate a method for maximal reproducibility of experimental acute myocardial infarction in the mouse model, due to a consistent loss of perfusion in the lower half of the left ventricle. This will allow the study of molecular and physiological variables in a controlled and quantifiable experimental model environment. (C) 2004 Elsevier Inc. All rights reserved.
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Teaching on social work values is centrally important in social work education as a core aspect of underpinning knowledge in preparing students for practice. This paper describes an innovative project occurring within the first year of the degree in social work, where service users and carers have assisted students with their understanding of social work values. The positive contribution of service users and carers in facilitating students to make links between theory and practice is now well documented. Applying this user perspective to the educational domain of values, however, is relatively uncharted territory given the challenges that have traditionally accompanied the teaching of values. Importantly, this paper describes the ‘value talk’ which occurred when first-year students sought further meaning from service-user and carer groups in their community settings following classroom teaching on values. The paper not only discusses the detailed preparations involved in the project but also the learning which resulted, drawing on the evaluation findings from the students and participating groups. Whilst the findings show that the students' understanding of social work values has been most significantly influenced by the contributions from service users and carers, it is recognized that further research is needed to monitor the longer term impact on social work students' practice after they qualify.
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This study investigates how habitat variation affects sett density, the number of animals per social group and group territory size in the badger (Meles meles). Identical methods were applied in three habitat types: lowland parkland with mixed woodland, pastoral farmland and upland rough pasture with moorland, representing areas of presumed good, medium and poor badger habitat, respectively. Contiguous main setts were identified and bait-marking was used to estimate territory size. Group size was estimated by direct enumeration. Variation in sett density, group size and territory size supported the hypothesis that badger group and territory size are influenced by habitat type. This was further supported by analyses of data from other studies in the British Isles. The implications for badger spatial ecology, badger survey techniques and the badger's role in the epidemiology of TB are discussed.
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To assess the efficiency of different agro-environmental strategies used to reduce groundwater pollution by nitrates, transport modelling in soils and groundwater has been carried out on two withdrawal areas in an alluvial plain. In a first time, the agro-environmental model AgriFlux allowed the simulation of water and nitrates fluxes flowing to groundwater. This model was calibrated for each agro-pedological unit of the studied territory. In a second time, the application of the hydrogeological model MODFLOW-MT3D allowed the simulation of nitrate transport in groundwater for the 1980-2004 period. This soil-groundwater coupled modelling has shown that soil nature is the first factor that conditions the vulnerability to nitrates. Thus, nitrate leaching occurs preferentially under sandy soils. Efficiency of different agro-environmental operations for groundwater quality recovery was quantified. The best results are obtained by combination of (1) grassland re-installation on sandy agricultural lots located in near well protection perimeter and (2) fertilization reduction on sandy agricultural lots located in the well alimentation area upstream the near protection perimeter. On other soils, the effect of grassland on groundwater quality improvement is more limited. Nevertheless, the control of nitrate fertilisation remains essential and is justified in both near and far well protection perimeters. Modelling thus allows optimising and priorizing agro-environmental actions in alluvial agricultural zones. [Comte J.-C., Banton O., Kockmann F., Villard A., Creuzot G. (2006), Assessment of groundwater quality recovery strategies using nitrate transport modelling. Application to the Saône alluvial formations (Tournus, Saône-et-Loire), Ingénieries Eau-Agriculture-Territoires, 45, 15-28]