Using intra-flock association patterns to understand why birds participate in mixed-species foraging flocks in terrestrial habitats

Bird species are hypothesized to join mixed-species flocks (flocks hereon) either for direct foraging or anti-predation-related benefits. In this study, conducted in a tropical evergreen forest in the Western Ghats of India, we used intra-flock association patterns to generate a community-wide assessment of flocking benefits for different species. We assumed that individuals needed to be physically proximate to particular heterospecific individuals within flocks to obtain any direct foraging benefit (flushed prey, kleptoparasitism, copying foraging locations). Alternatively, for anti-predation benefits, physical proximity to particular heterospecifics is not required, i.e. just being in the flock vicinity can suffice. Therefore, we used choice of locations within flocks to infer whether individual species are obtaining direct foraging or anti-predation benefits. A small subset of the bird community (5/29 species), composed of all members of the sallying guild, showed non-random physical proximity to heterospecifics within flocks. All preferred associates were from non-sallying guilds, suggesting that the sallying species were likely obtaining direct foraging benefits either in the form of flushed or kleptoparasitized prey. The majority of the species (24/29) chose locations randomly with respect to heterospecifics within flocks and, thus, were likely obtaining antipredation benefits. In summary, our study indicates that direct foraging benefits are important for only a small proportion of species in flocks and that predation is likely to be the main driver of flocking for most participants. Our findings apart, our study provides methodological advances that might be useful in understanding asymmetric interactions in social groups of single and multiple species.

Razões religiosas na esfera pública: uma análise teórica e empírica da atuação pentecostal no Poder Legislativo brasileiro

Os marcos da modernidade a secularização e a laicidade tem sido hoje postos em xeque por crescentes movimentos religiosos. As fronteiras entre Estado e religião estão sendo desafiadas e redefinidas. Dentro dessa renovação, coloca-se a questão da possibilidade ou não do uso de razões religiosas na esfera pública. O debate ganha importância no Brasil na medida em que o Pentecostalismo, ramo de Protestantismo em rápida expansão, fez afluir aos quadros do Congresso Nacional um número sem precedentes de candidatos eleitos graças à filiação religiosa. A análise teórica e empírica do uso de razões religiosas e da política pentecostal pretende jogar luz à questão, tendo sempre como paradigma, limite e orientação o fundamento último da liberdade religiosa: a dignidade da pessoa humana.

TEXTILE TECHNOLOGIES IN CONCRETE ENVIRONMENTS."

Girli Concrete is a cross disciplinary funded research project based in the University of Ulster involving a textile designer/ researcher, an architect/ academic and a concrete manufacturing firm.
Girli Concrete brings together concrete and textile technologies, testing ideas of
concrete as textile and textile as structure. It challenges the perception of textiles as only the ‘dressing’ to structure and instead integrates textile technologies into the products of building products. Girli Concrete uses ‘low tech’ methods of wet and dry concrete casting in combination with ‘high tech’ textile methods using laser cutting, etching, flocking and digital printing. Whilst we have been inspired by recent print and imprint techniques in architectural cladding, Girli Concrete is generated within the depth of the concrete’s cement paste “skin”, bringing the trades and crafts of both industries together with innovative results.
Architecture and Textiles have an odd, somewhat unresolved relationship. Confined to a subservient role in architecture, textiles exist chiefly within the categories of soft furnishings and interior design. Girli Concrete aims to mainstream tactility in the production of built environment products, raising the human and environmental interface to the same specification level as the technical. This paper will chart:
The background and wider theoretical concerns to the project.
The development of Girli Concrete, highlighting the areas where craft becomes
art and art becomes science in the combination of textile and concrete
technologies.
The challenges of identifying funding to support such combination technologies,
working methods and philosophies.
The challenges of generating and sustaining practice within an academic
research environment
The outcomes to date

Introducing the fractional-order Darwinian PSO

One of the most well-known bio-inspired algorithms used in optimization problems is the particle swarm optimization (PSO), which basically consists on a machinelearning technique loosely inspired by birds flocking in search of food. More specifically, it consists of a number of particles that collectively move on the search space in search of the global optimum. The Darwinian particle swarm optimization (DPSO) is an evolutionary algorithm that extends the PSO using natural selection, or survival of the fittest, to enhance the ability to escape from local optima. This paper firstly presents a survey on PSO algorithms mainly focusing on the DPSO. Afterward, a method for controlling the convergence rate of the DPSO using fractional calculus (FC) concepts is proposed. The fractional-order optimization algorithm, denoted as FO-DPSO, is tested using several well-known functions, and the relationship between the fractional-order velocity and the convergence of the algorithm is observed. Moreover, experimental results show that the FO-DPSO significantly outperforms the previously presented FO-PSO.

Particle swarm optimization for two-connected networks with bounded rings

The Two-Connected Network with Bounded Ring (2CNBR) problem is a network design problem addressing the connection of servers to create a survivable network with limited redirections in the event of failures. Particle Swarm Optimization (PSO) is a stochastic population-based optimization technique modeled on the social behaviour of flocking birds or schooling fish. This thesis applies PSO to the 2CNBR problem. As PSO is originally designed to handle a continuous solution space, modification of the algorithm was necessary in order to adapt it for such a highly constrained discrete combinatorial optimization problem. Presented are an indirect transcription scheme for applying PSO to such discrete optimization problems and an oscillating mechanism for averting stagnation.

Generating Aesthetically Pleasing Images in a Virtual Environment using Particle Swarm Optimization

This research focuses on generating aesthetically pleasing images in virtual environments using the particle swarm optimization (PSO) algorithm. The PSO is a stochastic population based search algorithm that is inspired by the flocking behavior of birds. In this research, we implement swarms of cameras flying through a virtual world in search of an image that is aesthetically pleasing. Virtual world exploration using particle swarm optimization is considered to be a new research area and is of interest to both the scientific and artistic communities. Aesthetic rules such as rule of thirds, subject matter, colour similarity and horizon line are all analyzed together as a multi-objective problem to analyze and solve with rendered images. A new multi-objective PSO algorithm, the sum of ranks PSO, is introduced. It is empirically compared to other single-objective and multi-objective swarm algorithms. An advantage of the sum of ranks PSO is that it is useful for solving high-dimensional problems within the context of this research. Throughout many experiments, we show that our approach is capable of automatically producing images satisfying a variety of supplied aesthetic criteria.

Interaction and Intelligent Behavior

We introduce basic behaviors as primitives for control and learning in situated, embodied agents interacting in complex domains. We propose methods for selecting, formally specifying, algorithmically implementing, empirically evaluating, and combining behaviors from a basic set. We also introduce a general methodology for automatically constructing higher--level behaviors by learning to select from this set. Based on a formulation of reinforcement learning using conditions, behaviors, and shaped reinforcement, out approach makes behavior selection learnable in noisy, uncertain environments with stochastic dynamics. All described ideas are validated with groups of up to 20 mobile robots performing safe--wandering, following, aggregation, dispersion, homing, flocking, foraging, and learning to forage.

Manage one beach or two? Movements and space-use of the threatened hooded plover (Thinornis rubricollis) in south-eastern Australia

An understanding of space use and dispersal of a wildlife species is essential for effective management. We examined the movements of a beach-dwelling, threatened population of hooded plover (Thinornis rubricollis) in southern central Victoria, Australia, by analysing sightings of colour-banded birds (4897 sightings; 194 birds tracked for up to 9 years). Most movements were relatively short (5050 ± 305 m), with 61.4% <1 km and 95.3% <20 km; they lacked directional or sexual bias. The extent of coastline used by individual birds was 47.8 ± 58.0 km. Regional differences in average distances moved by adults were apparent. For adults, movement rates (mean distance per day) were higher during the non-breeding season than during the breeding season. Non-breeding adults generally remained close to their partners (non-breeding, 456.3 ± 163.9 m; breeding, 148.2 ± 45.3 m). Largest flock sizes were recorded during the non-breeding period, and flocking was not uniformly distributed along the coast but appeared to be concentrated in particular locations. The frequency of pair cohesion (i.e. when the distance between partners was zero on a given day) was similar during the breeding (69.6%) and non-breeding seasons (67.7%). Breeding territories (kernel analysis) were 36.7 ± 5.7 ha and overlapped from year to year in all cases (23 pairwise comparisons; 47.9 ± 7.1% overlap). The high fidelity and constancy of territories confirms they warrant ongoing management investment, although the species relies on a matrix of breeding and non-breeding sites. The latter appear to occur in specific parts of the coast and warrant enhanced protection and more research attention. Fragmentation of the breeding population might occur where habitat is rendered unsuitable for > ~50 km.

Realistic autonomous fish for virtual reality

We create realistic autonomous fish for Virtual Reality systems. The fish are realistic in appearance, movement and behaviour: the swimming behaviour being non-scripted, within real time rendering.The form of the fish is procedurally created. The size and shape of the form are controlled by a number of variables which are stored in a simple ASCII file. This allows efficient creation of different fish at run time.The behaviour is obtained by implementing a flocking algorithm.

Flock inspired area coverage using wireless boid-like sensor agents

Simulated flocking is achievable using three boid rules [13]. We propose an area coverage model inspired by Reynolds’ flocking algorithm, investigating strategies for achieving quality coverage using flocking rules. Our agents are identical and autonomous, using only local sensory information for indirect communication. Upon deployment, agents are in the default separation mode. The cohesion rule would then guarantee that agents remain within the swarm, covering spaces with explored neighbour spaces. Four experiments are conducted to evaluate our model in terms of coverage quality achieved. We firstly investigate agents’ separation speed before the speed with which isolated agents re-organizes is investigated. The third experiment compares coverage quality achieved using our model with coverage quality achieved using random guessing. Finally, we investigate fault tolerance in the event of agents’ failures. Our model exhibits good separation and cohesion speed, achieving high quality coverage. Additionally, the model is fault tolerant and adaptive to agents’ failures.

From the Hill

Q&A: Personal loss leads to role as leading advocate of nonviolence in South Africa Business-Ready: Entrepreneurial Alliance has students flocking to the drawing board A Hand Up: Alumni consultants organize to give small businesses a boost Child's Play: Shelley Wollert wants kids to clamor for Elska, a musical, magical friend Poems that Explore "A World of Haunting Absences" A History of Putting a Spin on Vigilante Justice Old Glories Recent Releases Gardner Colby's Remarkable Mom Joining the Club: Ex-refugees, Somali boys have big impact on elite soccer team Hard Hitter: In the chemistry lab and on the field, John Gilboy Is "a no-quit kind of guy" Ravens assistant GM DeCosta Prepares for Future Role Scouting the NFL D-I Vet MacDonald Takes Over Men's Hockey

Decay of interspecific avian flock networks along a disturbance gradient in Amazonia

Our understanding of how anthropogenic habitat change shapes species interactions is in its infancy. This is in large part because analytical approaches such as network theory have only recently been applied to characterize complex community dynamics. Network models are a powerful tool for quantifying how ecological interactions are affected by habitat modification because they provide metrics that quantify community structure and function. Here, we examine how large-scale habitat alteration has affected ecological interactions among mixed-species flocking birds in Amazonian rainforest. These flocks provide a model system for investigating how habitat heterogeneity influences non-trophic interactions and the subsequent social structure of forest-dependent mixed-species bird flocks. We analyse 21 flock interaction networks throughout a mosaic of primary forest, fragments of varying sizes and secondary forest (SF) at the Biological Dynamics of Forest Fragments Project in central Amazonian Brazil. Habitat type had a strong effect on network structure at the levels of both species and flock. Frequency of associations among species, as summarized by weighted degree, declined with increasing levels of forest fragmentation and SF. At the flock level, clustering coefficients and overall attendance positively correlated with mean vegetation height, indicating a strong effect of habitat structure on flock cohesion and stability. Prior research has shown that trophic interactions are often resilient to large-scale changes in habitat structure because species are ecologically redundant. By contrast, our results suggest that behavioural interactions and the structure of non-trophic networks are highly sensitive to environmental change. Thus, a more nuanced, system-by-system approach may be needed when thinking about the resiliency of ecological networks.

Risk-based Modeling to Develop Zoning Criteria for Land-use Near Canadian Airports

Land development in the vicinity of airports often leads to land-use that can attract birds that are hazardous to aviation operations. For this reason, certain forms of land-use have traditionally been discouraged within prescribed distances of Canadian airports. However, this often leads to an unrealistic prohibition of land-use in the vicinity of airports located in urban settings. Furthermore, it is often unclear that the desired safety goals have been achieved. This paper describes a model that was created to assist in the development of zoning regulations for a future airport site in Canada. The framework links land-use to bird-related safety-risks and aircraft operations by categorizing the predictable relationships between: (i) different land uses found in urbanized and urbanizing settings near airports; (ii) bird species; and (iii) the different safety-risks to aircraft during various phases of flight. The latter is assessed relative to the runway approach and departure paths. Bird species are ranked to reflect the potential severity of an impact with an aircraft (using bird weight, flocking characteristics, and flight behaviours). These criteria are then employed to chart bird-related safety-risks relative to runway reference points. Each form of land-use is categorized to reflect the degree to which it attracts hazardous bird species. From this information, hazard and risk matrices have been developed and applied to the future airport setting, thereby providing risk-based guidance on appropriate land-uses that range from prohibited to acceptable. The framework has subsequently been applied to an existing Canadian airport, and is currently being adapted for national application. The framework provides a risk-based and science-based approach that offers municipalities and property owner’s flexibility in managing the risks to aviation related to their land use.

Modelli dinamici per fenomeni collettivi in fisica dei sistemi complessi

In questo lavoro si parla di un particolare comportamento emergente nei sistemi complessi: il flocking. Dopo aver dato una panoramica generale di come sia stato affrontato finora lo studio della formazione degli stormi, vengono portati come esempio un modello matematico e uno studio empirico particolare, il quale fonda le basi del flocking su un’interazione topologica. Il modello matematico, basato su un’interazione metrica, viene dapprima presentato, cercando di darne una parziale spiegazione tramite le proprietà delle matrici laplaciane, per poi essere testato attraverso delle simulazioni numeriche. Lo studio empirico, invece, viene presentato nei dettagli fornendo risultati e ipotesi atte a spiegarli. Infine prendendo spunto da questi due lavori, nell’ultima parte vengono posti a confronto due modelli, uno metrico e uno topologico, tramite simulazioni al calcolatore. L’esito di queste simulazioni conferma le ipotesi avanzate per spiegare i risultati empirici.

Temporal genetic structure and relatedness in the Tufted Duck Aythya fuligula suggests limited kin association in winter

Conspecific aggregation of waterfowl in winter is a common example of animal flocking behaviour, yet patterns of relatedness and temporal substructure in such social groups remain poorly understood even in common species. A previous study based on mark-recapture data showed that Tufted Ducks Aythya fuligula caught on the same day were re-caught together in subsequent winters more often than expected by chance, suggesting stable assortments of ‘socially familiar’ individuals between wintering periods. The genetic relationships within these social groups were not clear. Based on 191 individuals genotyped at 10 microsatellite markers, we investigated the temporal genetic structure and patterns of relatedness among wintering Tufted Ducks at Lake Sempach, Switzerland, in two consecutive winters. We found no evidence of genetic differentiation between temporal groups within or between winters. The average levels of relatedness in temporal groups were low and not higher than expected in random assortments of individuals. However, Mantel tests performed for each sex separately revealed significant negative correlations between the pairwise relatedness coefficients and the number of days between the capture dates of pairs of wintering Tufted Duck in males and females. This pattern suggests the presence of a small number of co-migrating same-sex sibling pairs in wintering flocks of Tufted Ducks. Our findings provide one of the first genetic analyses of a common duck species outside the breeding season and contribute to the understanding of social interactions in long-distance migratory birds.