bluuebunny/crossref_metadata_2025_split huggingface dataset:
Do Blackbirds Signal Motivation to Fight with Their Song?
Authors: Ripmeester Erwin A. P. , De Vries Anne M. , Slabbekoorn Hans 
Published: October 2007

AbstractConflicts about resources can be solved with physical fights, but animals will in general try to avoid them due to the costs and risks associated with fighting. Fight outcome depends on the fighting ability as well as the motivation to fight, which means that individuals should try to assess both during a pre‐escalation phase. In the present study, we investigated whether blackbirds (Turdus merula) acoustically signal their motivation to fight with their advertisement song, which consists of a motif part with pure‐toned low frequency elements followed by a twitter part with more complex and higher‐pitched elements. We tested (1) whether the temporal and spectral characteristics of spontaneous songs broadcasted by a territorial male could predict its subsequent aggressive behaviour to a playback and (2) if the song of territorial males changed in case they responded aggressively to the playback. We found no effects in the temporal song structure, which contradicts results from a previous study involving playback experiments with blackbirds. We did however find an interesting pattern in the spectral characteristics of the twitter, since aggressively responding males significantly increased the twitter frequency after the playback. The post‐playback songs of aggressive responders were nevertheless indistinguishable from spontaneous pre‐playback songs of non‐aggressive responders. Therefore, we conclude that changes in twitter frequency, rather than absolute twitter frequencies, are advertising information about motivation to fight.
Seeing What We Want to See: Confirmation Bias in Animal Behavior Research
Authors: Marsh David M. , Hanlon Teresa J. 
Published: October 2007

AbstractConfirmation bias is the tendency of observers to see what they expect to see while conducting scientific research. Although confirmation bias has been well‐studied by psychologists in the context of qualitative judgments, it has been much less studied with respect to the kinds of quantitative observations made by behavioral biologists. We carried out two experiments that used multiple observers of the aggression and foraging behaviors of red‐backed salamanders (Plethodon cinereus) to determine whether behavioral observations were influenced by the a priori expectations of observers. In both experiments, one group of observers was given a specific set of expectations with respect to sex differences in salamander behavior, while a second group was given the opposite set of expectations. In one experiment, observers collected data on variable sets of live salamanders, while in the other experiment, observers collected data from identical videotaped trials. Across experiments and observed behaviors, the expectations of observers did appear to bias observations, but only to a small or moderate degree. Confirmation bias never accounted for more than 13% of the observed variation in behavior, and was generally equivalent to <20% of the mean value of each variable. The estimated magnitude of confirmation bias was quite similar for men and women, suggesting no relationship between observer gender and susceptibility to confirmation bias. We believe that these results are largely optimistic with respect to confirmation bias in behavioral ecology, in that they suggest the bias may often be small relative to individual variation in behavior, even for relatively inexperienced observers.
Do Larval Damselflies make Adaptive Choices When Exposed to Both Parasites and Predators?
Authors: Rutherford Pamela L. , Baker Robert L. , Forbes Mark R. 
Published: October 2007

AbstractThe importance of multiple enemies from different trophic levels on investment in defence by prey has, with some exceptions, received little attention. Some defences may make the victim more susceptible to other enemies; this latter situation applies to predators and parasites of larval damselflies. Baker and Smith [Oecologia109 (1997) 622) showed that larval damselflies were as active in the presence of both mites and fish as they were when only mites were present, an apparently maladaptive behaviour that results in higher fish predation. In this paper, we further examine this maladaptive behavioural response to multiple enemies (fish predators and mite parasites) and test whether their defence responses are a result of the order in which they experience the parasite or predator, and/or if behavioural ‘personalities’ exist, such that some individuals show anti‐predator behaviours and other show anti‐parasite behaviours. Order of experience did not affect the four main behaviours (groom, crawl, turn and swim) exhibited when larval damselflies were simultaneously exposed to fish and mites. Grooming levels increased in response to mites, decreased in response to fish and when exposed to both mites and fish were similar to when they were exposed to mites alone. Duration of the other three behaviours was lower in the presence of both mites and fish. The crawling ‘personalities’ were evident. The apparently maladaptive response of high grooming levels in the presence of mites and fish is not a result of order of experience or ‘personalities’. It may be a result of relatively high encounter rates with mite parasites, compared with the encounter rates with fish. Lower encounter rates can result in diminishing investment in defence against an enemy.
Persistence of Alarm‐Call Behaviour in the Absence of Predators: A Comparison Between Wild and Captive‐Born Meerkats (Suricata Suricatta)
Authors: Hollén Linda I. , Manser Marta B. 
Published: October 2007

AbstractPerforming correct anti‐predator behaviour is crucial for prey to survive. But, are such abilities lost in species or populations living in predator‐free environments? How individuals respond to the loss of predators has been shown to depend on factors such as the degree to which anti‐predator behaviour relies on experience, the type of cues evoking the behaviour, the cost of expressing the behaviour and the number of generations under which relaxed selection has taken place. Here we investigated whether captive‐born populations of meerkats (Suricata suricatta) used the same repertoire of alarm calls previously documented in wild populations and whether captive animals, as wild ones, could recognize potential predators through olfactory cues. We found that all alarm calls that have been documented in the wild also occurred in captivity and were given in broadly similar contexts. Furthermore, without prior experience of odours from predators, captive meerkats seemed to distinguish between faeces of potential predators (carnivores) and non‐predators (herbivores). Despite slight structural differences, the alarm calls given in response to the faeces largely resembled those recorded in similar contexts in the wild. These results from captive populations suggest that direct, physical interaction with predators is not necessary for meerkats to perform correct anti‐predator behaviour in terms of alarm‐call usage and olfactory predator recognition. Such behaviour may have been retained in captivity because relatively little experience seems necessary for correct performance in the wild and/or because of the recency of relaxed selection on these populations.
Female Gryllus vocalis Field Crickets Gain Diminishing Returns from Increasing Numbers of Matings
Authors: Gershman Susan N. 
Published: October 2007

AbstractAlthough female insects generally gain reproductive benefits from mating frequently, females do not mate unlimited numbers of times. This study asks whether the limit on female mating rate is imposed by trade‐offs between reproduction and survival. Female Gryllus vocalis were given the opportunity to mate 5, 10, or 15 times with novel males, and the effects on daily fecundity (egg production), fertility (proportion of eggs that were fertilized), and female post‐experimental longevity were measured. Females that mated 10 times laid more eggs and had a higher proportion of fertile eggs than females that mated 5 times. However, females that mated 15 times did not lay significantly more eggs or have a higher proportion of fertile eggs than females that mated 10 times. Although number of matings did not affect the date that females laid their last egg, mating more times was associated with a prolonged period of laying fertile eggs. Number of matings did not affect female post‐experimental longevity. Thus, there was no trade‐off between female reproductive effort and survival, even when females mated very large numbers of times. When females were allowed to mate ad libitum, the average number of times that females mated was greater than the number of times that confers maximal fitness. The lack of cost to mating explains why females might be willing to mate beyond the point of diminishing reproductive returns.
Do Displays Send Information about Ornament Structure and Male Quality in the Ornate Tree Lizard,Urosaurus ornatus?
Authors: McElroy Eric J. , Marien Chloe , Meyers Jay J. , Irschick Duncan J. 
Published: October 2007

AbstractDisplays can transmit information about ornament or male quality; however, few studies have simultaneously explored the relationship between displays, ornament and male quality within a single species. We quantified ornament morphology (five throat color morphs, throat area, and belly area), male quality (bite force, sprint speed, body condition, and body mass), display behavior [percent time displaying (PTD), number of pushups per display, and display duration], and movement behavior among males in a population of the ornate tree lizard,Urosaurus ornatus. Previous studies have shown that maleU. ornatusare polymorphic in throat coloration and that morphs differ in behavioral aggression. Our study shows that blue throat morphs use 1.5 more pushups per display than other male color morphs, which suggests that throat color and display behavior act as backup signals for aggression. However, other data support the multiple messages hypothesis, and overall our data do not provide conclusive evidence for any one hypothesis. In addition, we show that body mass is positively related to both PTD and percent time moving and this relationship is independent of color morph. We also found that throat area, belly area, bite force, sprint speed, and body condition are unrelated to display behavior. This result highlights at least some discordance between display behavior, ornaments, and performance inU. ornatusand suggests that these traits may be evolving independently.
Direct Familiarity Does Not Alter Mating Preference for Sisters in MalePelvicachromis taeniatus(Cichlidae)
Authors: Thünken Timo , Bakker Theo C. M. , Baldauf Sebastian A. , Kullmann Harald 
Published: October 2007

AbstractIn social species, individuals who grew up together are usually relatives. Therefore, direct familiarity is normally a reliable kin recognition mechanism that is used in many species to discriminate kin from non‐kin. It has been shown in animals and in humans that familiar individuals are rejected as mating partners in order to circumvent potential costs of inbreeding. Here, we tested whether direct familiarity also leads to inbreeding avoidance behaviour in malePelvicachromis taeniatus, a small socially monogamous cichlid with biparental brood care. In mate choice experiments, reproductively active males were given the choice between familiar sisters and unfamiliar, unrelated females. In a previous study, both sexes ofP. taeniatushad preferred unfamiliar full‐sibs over unfamiliar unrelated individuals as mating partners. Here, we show that direct familiarity does not alter the male preference for closely related females. This result is in accordance with theoretical predictions, that inbreeding can be advantageous under certain conditions, and confirms previous findings, that active inbreeding is an adaptive strategy inP. taeniatus.
Prevalence of obesity in 6‐ and 9‐year‐old children living in Central‐North Italy. Analysis of determinants and indicators of risk of overweight
Authors: Albertini A. , Tripodi A. , Fabbri A. , Mattioli M. , Cavrini G. , Cecchetti R. , Dalle Donne E. , Cortesi C. , De Giorgi S. , Contarini V. , Andreotti L. , Veronesi B. , Stefanelli I. , Di Martino E. 
Published: October 2007

SummaryThe objective of our article is to survey the prevalence of overweight and obesity among 6‐ and 9‐year‐old children in Emilia‐Romagna, a region of Central‐North Italy, and to study the eating habits and behaviours of these children and their families.During 2003 and 2005, we analysed a stratified sample of the general population of children attending pre‐school (2681 children aged 6 years) and primary school (2955 children aged 9 years). Their height and weight were measured by healthcare workers. In the 6‐year‐old children, information concerning their eating habits was collected by means of a questionnaire completed by their parents.The prevalence of overweight was 16.5% in 6‐year‐old children and 20.6% in 9‐year‐old children. The increase of overweight from 6‐ to 9‐year‐old children was observed in males (13.5% in 6‐year‐old/21.3% in 9‐year‐old boys), but not in females. The prevalence of obesity was 8.9% in children aged 6 years and 9.0% in those aged 9 years, and it was higher in comparison with Italian surveys carried out in 1993 and in 2001: 7.5% in 6‐year‐old and 7.8% in 9‐year‐old children in 1993, and 6.6% in 6‐year‐old and 7.2% in 9‐year‐old children in 2001. In pre‐school children, overweight and obesity were closely influenced by the education level, occupation and nutritional status of the parents.
Serious Games: Broadening Games Impact Beyond Entertainment
Authors: Sawyer Ben 
Published: October 2007

Abstract Computer and videogames for many years has been an island of technology and design innovation largely left to itself as it morphed from a cottage business into a global media and software industry. While there have been pockets of derivative activity related to games and game technology only in the last half‐dozen years has there been a real movement toward exploiting this industry in many new and exciting ways. Today the general use of games and game technologies for purposes beyond entertainment is collectively referred to as serious games. The Serious Games Initiative was formed in 2002 and since its inception has been among a number of critical efforts that has helped open up the world and many disciplines to the ideas and innovations that may be sourced from the commercial, independent, and academic game fields. This has been a person‐by‐person, project‐by‐project effort that not only has informed us about the potential of games but also in how you merge innovation and innovators from one discipline with those in another. In this talk we will explore the total gamut of the serious games field identifying past the obvious how games and game technologies are being applied to problems in a wide array of areas including healthcare, productivity, visualization, science, and of course training and education. Once a proper definition of serious games is established the talk will focus on the current state of the field as it relates to research and infrastructure issues that are needed to make the difference between seeing serious games take hold as a major new practice or having it devolve into another trend of the moment lost to history.
Soft Articulated Characters with Fast Contact Handling
Authors: Galoppo Nico , Otaduy Miguel A. , Tekin Serhat , Gross Markus , Lin Ming C. 
Published: October 2007

Abstract Fast contact handling of soft articulated characters is a computationally challenging problem, in part due to complex interplay between skeletal and surface deformation. We present a fast, novel algorithm based on a layered representation for articulated bodies that enables physically‐plausible simulation of animated characters with a high‐resolution deformable skin in real time. Our algorithm gracefully captures the dynamic skeleton‐skin interplay through a novel formulation of elastic deformation in the pose space of the skinned surface. The algorithm also overcomes the computational challenges by robustly decoupling skeleton and skin computations using careful approximations of Schur complements, and efficiently performing collision queries by exploiting the layered representation. With this approach, we can simultaneously handle large contact areas, produce rich surface deformations, and capture the collision response of a character/s skeleton.
3D Lip‐Synch Generation with Data‐Faithful Machine Learning
Authors: Kim Ig‐Jae , Ko Hyeong‐Seok 
Published: October 2007

Abstract This paper proposes a new technique for generating three‐dimensional speech animation. The proposed technique takes advantage of both data‐driven and machine learning approaches. It seeks to utilize the most relevant part of the captured utterances for the synthesis of input phoneme sequences. If highly relevant data are missing or lacking, then it utilizes less relevant (but more abundant) data and relies more heavily on machine learning for the lip‐synch generation. This hybrid approach produces results that are more faithful to real data than conventional machine learning approaches, while being better able to handle incompleteness or redundancy in the database than conventional data‐driven approaches. Experimental results, obtained by applying the proposed technique to the utterance of various words and phrases, show that (1) the proposed technique generates lip‐synchs of different qualities depending on the availability of the data, and (2) the new technique produces more realistic results than conventional machine learning approaches.
Adaptive Space Deformations Based on Rigid Cells
Authors: Botsch Mario , Pauly Mark , Wicke Martin , Gross Markus 
Published: October 2007

Abstract We propose a new adaptive space deformation method for interactive shape modeling. A novel energy formulation based on elastically coupled volumetric cells yields intuitive detail preservation even under large deformations. By enforcing rigidity of the cells, we obtain an extremely robust numerical solver for the resulting nonlinear optimization problem. Scalability is achieved using an adaptive spatial discretization that is decoupled from the resolution of the embedded object. Our approach is versatile and easy to implement, supports thin‐shell and solid deformations of 2D and 3D objects, and is applicable to arbitrary sample‐based representations, such as meshes, triangle soups, or point clouds.
A Finite Element Method on Convex Polyhedra
Authors: Wicke Martin , Botsch Mario , Gross Markus 
Published: October 2007

Abstract We present a method for animating deformable objects using a novel finite element discretization on convex polyhedra. Our finite element approach draws upon recently introduced 3D mean value coordinates to define smooth interpolants within the elements. The mathematical properties of our basis functions guarantee convergence. Our method is a natural extension to linear interpolants on tetrahedra: for tetrahedral elements, the methods are identical. For fast and robust computations, we use an elasticity model based on Cauchy strain and stiffness warping. This more flexible discretization is particularly useful for simulations that involve topological changes, such as cutting or fracture. Since splitting convex elements along a plane produces convex elements, remeshing or subdivision schemes used in simulations based on tetrahedra are not necessary, leading to less elements after such operations. We propose various operators for cutting the polyhedral discretization. Our method can handle arbitrary cut trajectories, and there is no limit on how often elements can be split.
Ray‐Casted BlockMaps for Large Urban Models Visualization
Authors: Cignoni P. , Di Benedetto M. , Ganovelli F. , Gobbetti E. , Marton F. , Scopigno R. 
Published: October 2007

Abstract We introduce a GPU‐friendly technique that efficiently exploits the highly structured nature of urban environments to ensure rendering quality and interactive performance of city exploration tasks. Central to our approach is a novel discrete representation, called BlockMap, for the efficient encoding and rendering of a small set of textured buildings far from the viewer. A BlockMap compactly represents a set of textured vertical prisms with a bounded on‐screen footprint. BlockMaps are stored into small fixed size texture chunks and efficiently rendered through GPU raycasting. Blockmaps can be seamlessly integrated into hierarchical data structures for interactive rendering of large textured urban models. We illustrate an efficient output‐sensitive framework in which a visibility‐aware traversal of the hierarchy renders components close to the viewer with textured polygons and employs BlockMaps for far away geometry. Our approach provides a bounded size far distance representation of cities, naturally scales with the improving shader technology, and outperforms current state of the art approaches. Its efficiency and generality is demonstrated with the interactive exploration of a large textured model of the city of Paris on a commodity graphics platform.
Metropolis Instant Radiosity
Authors: Segovia B. , Iehl J.C. , Péroche B. 
Published: October 2007

Abstract We present Metropolis Instant Radiosity (MIR), an unbiased algorithm to solve the Light Transport problem. MIR is a hybrid technique which consists in representing the incoming radiance field by a set of Virtual Point Lights (V PLs) and in computing the response of all sensors in the scene (i.e. camera captors) by accumulating their contributions. In contrast to other similar approaches, we propose to sample the VPLs with an innovative Multiple‐try Metropolis‐Hastings (MTMH) Algorithm: the goal is to build an efficient, aggressive, and unconditionally robust variance reduction method that works well regardless of the scene layout. Finally, we present a fast ray tracing implementation using MIR and show how our complete rendering pipeline can produce high‐quality and high‐resolution pictures in a few seconds.
Superresolution Reflectance Fields: Synthesizing images for intermediate light directions
Authors: Fuchs Martin , Lensch Hendrik P. A. , Blanz Volker , Seidel Hans‐Peter 
Published: October 2007

Abstract Captured reflectance fields tend to provide a relatively coarse sampling of the incident light directions. As a result, sharp illumination features, such as highlights or shadow boundaries, are poorly reconstructed during relighting; highlights are disconnected, and shadows show banding artefacts. In this paper, we propose a novel interpolation technique for 4D reflectance fields that reconstructs plausible images even for non‐observed light directions. Given a sparsely sampled reflectance field, we can effectively synthesize images as they would have been obtained from denser sampling. The processing pipeline consists of three steps: (1) segmentation of regions where intermediate lighting cannot be obtained by blending, (2) appropriate flow algorithms for highlights and shadows, plus (3) a final reconstruction technique that uses image‐based priors to faithfully correct errors that might be introduced by the segmentation or flow step. The algorithm reliably reproduces scenes that contain specular highlights, interreflections, shadows or caustics.