bluuebunny/crossref_metadata_2025 huggingface dataset:
Character Motion Synthesis by Topology Coordinates
Authors: Ho Edmond S.L. , Komura Taku
Published: March 2009

In this paper, we propose a new method to efficiently synthesize character motions that involve close contacts such as wearing a T‐shirt, passing the arms through the strings of a knapsack, or piggy‐back carrying an injured person. We introduce the concept of topology coordinates, in which the topological relationships of the segments are embedded into the attributes. As a result, the computation for collision avoidance can be greatly reduced for complex motions that require tangling the segments of the body. Our method can be combinedly used with other prevalent frame‐based optimization techniques such as inverse kinematics.
An Analytical Solution to Single Scattering in Homogeneous Participating Media
Authors: Pegoraro Vincent , Parker Steven G.
Published: March 2009

Despite their numerous applications, efficiently rendering participating media remains a challenging task due to the intricacy of the radiative transport equation. As they provide a generic means of solving a wide variety of problems, numerical methods are most often used to solve the air‐light integral even under simplifying assumptions. In this paper, we present a novel analytical approach to single scattering from isotropic point light sources in homogeneous media. We derive the first closed‐form solution to the air‐light integral in isotropic media and extend this formulation to anisotropic phase functions. The technique relies neither on pre‐computation nor on storage, and we provide a practical implementation allowing for an explicit control on the accuracy of the solutions. Finally, we demonstrate its quantitative and qualitative benefits over both previous numerical and analytical approaches.
A Statistical Model of Human Pose and Body Shape
Authors: Hasler N. , Stoll C. , Sunkel M. , Rosenhahn B. , Seidel H.‐P.
Published: March 2009

Generation and animation of realistic humans is an essential part of many projects in today's media industry. Especially, the games and special effects industry heavily depend on realistic human animation. In this work a unified model that describes both, human pose and body shape is introduced which allows us to accurately model muscle deformations not only as a function of pose but also dependent on the physique of the subject. Coupled with the model's ability to generate arbitrary human body shapes, it severely simplifies the generation of highly realistic character animations. A learning based approach is trained on approximately 550 full body 3D laser scans taken of 114 subjects. Scan registration is performed using a non‐rigid deformation technique. Then, a rotation invariant encoding of the acquired exemplars permits the computation of a statistical model that simultaneously encodes pose and body shape. Finally, morphing or generating meshes according to several constraints simultaneously can be achieved by training semantically meaningful regressors.
Motion Compression using Principal Geodesics Analysis
Authors: Tournier M. , Wu X. , Courty N. , Arnaud E. , Revéret L.
Published: March 2009

Due to the growing need for large quantities of human animation data in the entertainment industry, it has become a necessity to compress motion capture sequences in order to ease their storage and transmission. We present a novel, lossy compression method for human motion data that exploits both temporal and spatial coherence. Given one motion, we first approximate the poses manifold using Principal Geodesics Analysis (PGA) in the configuration space of the skeleton. We then search this approximate manifold for poses matching end‐effectors constraints using an iterative minimization algorithm that allows for real‐time, data‐driven inverse kinematics. The compression is achieved by only storing the approximate manifold parametrization along with the end‐effectors and root joint trajectories, also compressed, in the output data. We recover poses using the IK algorithm given the end‐effectors trajectories. Our experimental results show that considerable compression rates can be obtained using our method, with few reconstruction and perceptual errors.
Fast GPU‐based Adaptive Tessellation with CUDA
Authors: Schwarz Michael , Stamminger Marc
Published: March 2009

Compact surface descriptions like higher‐order surfaces are popular representations for both modeling and animation. However, for fast graphics‐hardware‐assisted rendering, they usually need to be converted to triangle meshes. In this paper, we introduce a new framework for performing on‐the‐fly crack‐free adaptive tessellation of surface primitives completely on the GPU. Utilizing CUDA and its flexible memory write capabilities, we parallelize the tessellation task at the level of single surface primitives. We are hence able to derive tessellation factors, perform surface evaluation as well as generate the tessellation topology in real‐time even for large collections of primitives. We demonstrate the power of our framework by exemplarily applying it to both bicubic rational Bézier patches and PN triangles.
Out‐of‐core Data Management for Path Tracing on Hybrid Resources
Authors: Budge Brian , Bernardin Tony , Stuart Jeff A. , Sengupta Shubhabrata , Joy Kenneth I. , Owens John D.
Published: March 2009

We present a software system that enables path‐traced rendering of complex scenes. The system consists of two primary components: an application layer that implements the basic rendering algorithm, and an out‐of‐core scheduling and data‐management layer designed to assist the application layer in exploiting hybrid computational resources (e.g., CPUs and GPUs) simultaneously. We describe the basic system architecture, discuss design decisions of the system's data‐management layer, and outline an efficient implementation of a path tracer application, where GPUs perform functions such as ray tracing, shadow tracing, importance‐driven light sampling, and surface shading. The use of GPUs speeds up the runtime of these components by factors ranging from two to twenty, resulting in a substantial overall increase in rendering speed. The path tracer scales well with respect to CPUs, GPUs and memory per node as well as scaling with the number of nodes. The result is a system that can render large complex scenes with strong performance and scalability.
A Part‐aware Surface Metric for Shape Analysis
Authors: Liu Rong , Zhang Hao , Shamir Ariel , Cohen‐Or Daniel
Published: March 2009

The notion of parts in a shape plays an important role in many geometry problems, including segmentation, correspondence, recognition, editing, and animation. As the fundamental geometric representation of 3D objects in computer graphics is surface‐based, solutions of many such problems utilize a surface metric, a distance function defined over pairs of points on the surface, to assist shape analysis and understanding. The main contribution of our work is to bring together these two fundamental concepts: shape parts and surface metric. Specifically, we develop a surface metric that is part‐aware. To encode part information at a point on a shape, we model its volumetric context – called the volumetric shape image (VSI) – inside the shape's enclosed volume, to capture relevant visibility information. We then define the part‐aware metric by combining an appropriate VSI distance with geodesic distance and normal variation. We show how the volumetric view on part separation addresses certain limitations of the surface view, which relies on concavity measures over a surface as implied by the well‐known minima rule. We demonstrate how the new metric can be effectively utilized in various applications including mesh segmentation, shape registration, part‐aware sampling and shape retrieval.
Genuinity Signatures: Designing Signatures for Verifying 3D Object Genuinity
Authors: Aliaga Daniel G. , Atallah Mikhail J.
Published: March 2009

3D computer graphics models and digitally‐controlled manufacturing have come together to enable the design, visualization, simulation, and automated creation of complex 3D objects. In our work, we propose and implement a framework for designing computer graphics objects and digitally manufacturing them such that no adversary can make imitations or counterfeit copies of the physical object, even if the adversary has a large number of original copies of the object, knowledge of the original object design, and has manufacturing precision that is comparable to or superior to that of the legitimate creator of the object. Our approach is to design and embed a signature on the surface of the object which acts as a certificate of genuinity of the object. The signature is detectable by a signature‐reading device, based on methods in computer graphics and computer vision, which contains some of the secret information that was used when marking the physical object. Further, the compromise of a signature‐reading device by an adversary who is able to extract all its secrets, does not enable the adversary to create counterfeit objects that fool other readers, thereby still enabling reliable copy detection. We implemented a prototype of our scheme end‐to‐end, including the production of the physical object and the genuinity‐testing device.
Arches: a Framework for Modeling Complex Terrains
Authors: Peytavie A. , Galin E. , Grosjean J. , Merillou S.
Published: March 2009

In this paper, we present a framework for representing complex terrains with such features as overhangs, arches and caves and including different materials such as sand and rocks. Our hybrid model combines a volumetric discrete data structure that stores the different materials and an implicit representation for sculpting and reconstructing the surface of the terrain. Complex scenes can be edited and sculpted interactively with high level tools. We also propose an original rock generation technique that enables us to automatically generate complex rocky sceneries with piles of rocks without any computationally demanding physically‐based simulation.
Structure‐Preserving Reshape for Textured Architectural Scenes
Authors: Cabral Marcio , Lefebvre Sylvain , Dachsbacher Carsten , Drettakis George
Published: March 2009

Modeling large architectural environments is a difficult task due to the intricate nature of these models and the complex dependencies between the structures represented. Moreover, textures are an essential part of architectural models. While the number of geometric primitives is usually relatively low (i.e., many walls are at surfaces), textures actually contain many detailed architectural elements.

We present an approach for modeling architectural scenes by reshaping and combining existing textured models, where the manipulation of the geometry and texture are tightly coupled. For geometry, preserving angles such as oor orientation or vertical walls is of key importance. We thus allow the user to interactively modify lengths of edges, while constraining angles. Our texture reshaping solution introduces a measure of directional autosimilarity to focus stretching in areas of stochastic content and to preserve details in such areas.

We show results on several challenging models, and show two applications: Building complex road structures from simple initial pieces and creating complex game‐levels from an existing game based on pre‐existing model pieces.
Completion and Reconstruction with Primitive Shapes
Authors: Schnabel Ruwen , Degener Patrick , Klein Reinhard
Published: March 2009

We consider the problem of reconstruction from incomplete point‐clouds. To find a closed mesh the reconstruction is guided by a set of primitive shapes which has been detected on the input point‐cloud (e.g. planes, cylinders etc.). With this guidance we not only continue the surrounding structure into the holes but also synthesize plausible edges and corners from the primitives' intersections. To this end we give a surface energy functional that incorporates the primitive shapes in a guiding vector field. The discretized functional can be minimized with an efficient graph‐cut algorithm. A novel greedy optimization strategy is proposed to minimize the functional under the constraint that surface parts corresponding to a given primitive must be connected. From the primitive shapes our method can also reconstruct an idealized model that is suitable for use in a CAD system.
Heightfield and spatially varying BRDF Reconstruction for Materials with Interreflections
Authors: Ruiters Roland , Klein Reinhard
Published: March 2009

Photo‐realistic reproduction of material appearance from images has widespread use in applications ranging from movies over advertising to virtual prototyping. A common approach to this task is to reconstruct the small scale geometry of the sample and to capture the reflectance properties using spatially varying BRDFs. For this, multi‐view and photometric stereo reconstruction can be used, both of which are limited regarding the amount of either view or light directions and suffer from either low‐ or high‐frequency artifacts, respectively. In this paper, we propose a new algorithm combining both techniques to recover heightfields and spatially varying BRDFs while at the same time overcoming the above mentioned drawbacks. Our main contribution is a novel objective function which allows for the reconstruction of a heightfield and high quality SVBRDF including view dependent effects. Thereby, our method also avoids both low and high frequency artifacts. Additionally, our algorithm takes inter‐reflections into account allowing for the reconstruction of undisturbed representations of the underlying material. In our experiments, including synthetic and real‐world data, we show that our approach is superior to state‐of‐the‐art methods regarding reconstruction error as well as visual impression. Both the reconstructed geometry and the recovered SVBRDF are highly accurate, resulting in a faithful reproduction of the materials characteristic appearance, which is of paramount importance in the context of material rendering.
Wind projection basis for real‐time animation of trees
Authors: Diener Julien , Rodriguez Mathieu , Baboud Lionel , Reveret Lionel
Published: March 2009

This paper presents a real‐time method to animate complex scenes of thousands of trees under a user‐controllable wind load. Firstly, modal analysis is applied to extract the main modes of deformation from the mechanical model of a 3D tree. The novelty of our contribution is to precompute a new basis of the modal stress of the tree under wind load. At runtime, this basis allows to replace the modal projection of the external forces by a direct mapping for any directional wind. We show that this approach can be efficiently implemented on graphics hardware. This modal animation can be simulated at low computation cost even for large scenes containing thousands of trees.
Positional, Metric, and Curvature Control for Constraint‐Based Surface Deformation
Authors: Eigensatz Michael , Pauly Mark
Published: March 2009

We present a geometry processing framework that allows direct manipulation or preservation of positional, metric, and curvature constraints anywhere on the surface of a geometric model. Target values for these properties can be specified point‐wise or as integrated quantities over curves and surface patches embedded in the shape. For example, the user can draw several curves on the surface and specify desired target lengths, manipulate the normal curvature along these curves, or modify the area or principal curvature distribution of arbitrary surface patches. This user input is converted into a set of non‐linear constraints. A global optimization finds the new deformed surface that best satisfies the constraints, while minimizing adaptable measures for metric and curvature distortion that provide explicit control of the deformation semantics. We illustrate how this approach enables flexible surface processing and shape editing operations not available in current systems.
Continuum‐based Strain Limiting
Authors: Thomaszewski Bernhard , Pabst Simon , Straßer Wolfgang
Published: March 2009

We present Continuum‐based Strain Limiting (CSL) – a new method for limiting deformations in physically‐based cloth simulations. Despite recent developments for nearly inextensible materials, the efficient simulation of general biphasic textiles and their anisotropic behavior remains challenging. Many approaches use soft materials and enforce limits on edge elongations, leading to discretization‐dependent behavior. Moreover, they offer no explicit control over shearing and stretching unless specifically aligned meshes are used. Based on a continuum deformation measure, our method allows accurate control over all strain components using individual thresholds. We impose deformation limits element‐wise and cast the problem as a 6×6 system of linear equations. CSL can be combined with any cloth simulator and, as a velocity filter, integrates seamlessly into standard collision handling.
Deblurring by Matching
Authors: Ancuti Cosmin , Ancuti Codruta Orniana , Bekaert Philippe
Published: March 2009

Restoration of the photographs damaged by the camera shake is a challenging task that manifested increasing attention in the recent period. Despite of the important progress of the blind deconvolution techniques, due to the ill‐posed nature of the problem, the finest details of the kernel blur cannot be recovered entirely. Moreover, the additional constraints and prior assumptions make these approaches to be relative limited.

In this paper we introduce a novel technique that removes the undesired blur artifacts from photographs taken by hand‐held digital cameras. Our approach is based on the observation that in general several consecutive photographs taken by the users share image regions that project the same scene content. Therefore, we took advantage of additional sharp photographs of the same scene. Based on several invariant local feature points, filtered from the given blurred/non‐blurred images, our approach matches the keypoints and estimates the blur kernel using additional statistical constraints.

We also present a simple deconvolution technique that preserves edges while minimizing the ringing artifacts in the restored latent image. The experimental results prove that our technique is able to infer accurately the blur kernel while reducing significantly the artifacts of the spoilt images.
Dominant Texture and Diffusion Distance Manifolds
Authors: Lu Jianye , Dorsey Julie , Rushmeier Holly
Published: March 2009

Texture synthesis techniques require nearly uniform texture samples, however identifying suitable texture samples in an image requires significant data preprocessing. To eliminate this work, we introduce a fully automatic pipeline to detect dominant texture samples based on a manifold generated using the diffusion distance. We define the characteristics of dominant texture and three different types of outliers that allow us to efficiently identify dominant texture in feature space. We demonstrate how this method enables the analysis/synthesis of a wide range of natural textures. We compare textures synthesized from a sample image, with and without dominant texture detection. We also compare our approach to that of using a texture segmentation technique alone, and to using Euclidean, rather than diffusion, distances between texture features.
Table‐based Alpha Compression
Authors: Wennersten Per , Ström Jacob
Published: March 2009

In this paper we investigate low‐bitrate compression of scalar textures such as alpha maps, down to one or two bits per pixel. We present two new techniques for 4 × 4 blocks, based on the idea from ETC to use index tables. We demonstrate that although the visual quality of the alpha maps is greatly reduced at these low bit rates, the quality of the final rendered images appears to be sufficient for a wide range of applications, thus allowing bandwidth savings of up to 75%. The 2 bpp version improves PSNR with over 2 dB compared to BTC at the same bit rate. The 1 bpp version is, to the best of our knowledge, the first public 1 bpp texture compression algorithm, which makes comparison hard. However, compared to just DXT5‐compressing a subsampled texture, our 1 bpp technique improves PSNR with over 2 dB. Finally, we show that some aspects of the presented algorithms are also useful for the more common bit rate of four bits per pixel, achieving PSNR scores around 1 dB better than DXT5, over a set of test images.
Detecting Symmetries and Curvilinear Arrangements in Vector Art
Authors: Yeh Yi‐Ting , Měch Radomír
Published: March 2009

Understanding symmetries and arrangements in existing content is the first step towards providing higher level content aware editing capabilities. Such capabilities may include edits that both preserve existing structure as well as synthesize entirely new structures based on the extracted pattern rules. In this paper we show how to detect regular symmetries and arrangement along curved segments in vector art. We determine individual elements in the art by using the transformation similarity for sequences of sample points on the input curves. Then we detect arrangements of those elements along an arbitrary curved path. We can un‐warp the arrangement path to detect symmetries near the path. We introduce novel applications inform of editing elements that are arranged along a curved path. This includes their sliding along the path, changing of their spacing, or their scale. We also allow the user to brush the elements that the system recognized along new paths.
Quality of life in 1000 patients with early relapsing–remitting multiple sclerosis
Authors: Putzki N. , Fischer J. , Gottwald K. , Reifschneider G. , Ries S. , Siever A. , Hoffmann F. , Käfferlein W. , Kausch U. , Liedtke M. , Kirchmeier J. , Gmünd S. , Richter A. , Schicklmaier P. , Niemczyk G. , Wernsdörfer C. , Hartung H. P. ,   for the “Mensch im Mittelpunkt” Study Group
Published: March 2009

Background and purpose:  To examine the quality of life (QoL) in a large cohort of untreated patients with relapsing–remitting multiple sclerosis (RRMS) and to investigate the impact of intramuscular (IM) interferon beta‐1a (IFNß‐1a) treatment.

Methods:  Prospective, observational, open‐label, multicentre study conducted in Germany. Untreated patients with RRMS who initiated treatment with IM IFNß‐1a were included and followed for 12 months. QoL was measured using the EQ‐5D questionnaire. Clinical response was assessed by relapse rate and disability (Expanded Disability Status Scale; EDSS).

Results:  A total of 1157 patients were included [mean age 37.6 years, median disease duration 13 months, mean relapse rate 1.7 (95%CI: 1.58–1.73), median EDSS score 2.0]. Relapse rate was reduced to 0.6 at 12 months (95%CI: 0.51–0.69, P < 0.0001). EDSS did not change significantly. At baseline, QoL was considerably lower in MS patients compared with the general German population, but was improved after treatment initiation [utilities of EQ‐5D: 0.77 (95%CI: 0.75–0.78) vs. 0.75 (95%CI: 0.74–0.76) at baseline, 95%CI for difference: 0.01–0.03, P = 0.0046]. Higher disease activity and inability to work were negative predictors of QoL. 14.7% of patients were incapable of working for MS‐related reasons.

Conclusions:  Quality of life is considerably impaired in early stages of MS. Treatment initiation with IM IFNß attenuates MS disease activity and improves QoL. Inability to work early during the disease is a major challenge for the social security systems.
Development of Doctrine, or Denial? Balthasar's Holy Saturday and Newman's Essay
Authors: PITSTICK ALYSSA
Published: March 2009

Edward Oakes generalized Newman's seven tests for doctrinal development as ‘internal logic’ and ‘developmental consistency’. Using this reduction, he claimed Newman's support for Balthasar's theology of Christ's descent into hell. In fairness to Newman and for a more adequate evaluation of Balthasar, I let Newman speak for himself. His norms are applied to both the traditional doctrine and Balthasar's. Since Balthasar's lacks all seven, it follows it is not a development of doctrine, but a corruption. Oakes' other arguments insufficiently counterbalance this deduction, while the traditional doctrine offers insights into the questions of pluralism and the salvation of the non‐baptized.
‘The Cruciality of the Cross’: P.T. Forsyth's Understanding of the Atonement
Authors: LEOW THENG‐HUAT
Published: March 2009

The writings of British Congregationalist theologian Peter Taylor Forsyth (1848–1921), although traversing a wide range of topics, revolve around a clear centre – his understanding of the significance of the death of Christ on the cross. Commentators on his thought have, however, lamented the occasional nature of his writings on this central doctrine of the atonement, and highlighted aspects of his thought which require clarification. This article seeks to respond to these observations by presenting a fairly complete and systematic view of Forsyth's understanding of the atonement, supplementing his explicit statements where necessary by drawing out the implications of his writings. We hope, at the end, to have demonstrated the robustness of Forsyth's treatment of the atonement, especially its ability to integrate the diverse areas of thought traditionally associated with this doctrine.
Altruism and Volunteerism: The perceptions of altruism in four disciplines and their impact on the study of volunteerism
Authors: HASKI‐LEVENTHAL DEBBIE
Published: March 2009

Although volunteering is the most organized and formal manner of altruism, the two subjects are rarely connected in literature. In this article reviewed is the egocentric approach that is found in four social disciplines: psychology, sociology, economics and socio‐biology (evolutionism), and the way that studies on altruism are based on Utilitarian philosophy and on thehomo economicusperception of man. All of the above have influenced the study of volunteerism: the research questions, the study areas, and the conclusions on the essence of volunteering. We then review a different approach based on Deontological philosophy: the alter‐centric approach, already influencing the study of altruism. New directions of approaching and studying volunteerism are suggested.
Construction and Deconstruction of Essence in Representating Social Groups: Identity Projects, Stereotyping, and Racism
Authors: WAGNER WOLFGANG , HOLTZ PETER , KASHIMA YOSHIHISA
Published: March 2009

Projecting essence onto a social category means to think, talk, and act as if the category were a discrete natural kind and as if its members were all endowed with the same immutable attributes determined by the category's essence. Essentializing may happen implicitly or on purpose in representing ingroups and outgroups. We argue that essentializing is a versatile representational tool (a) that is used to create identity in groups with chosen membership in order to make the group appear as a unitary entity, (b) that outsiders often draw on a group's essentialist self‐construal in their judgements about the groups, (c) that judgements about members of forced social categories are often informed by essentialist thinking that easily switches to discrimination and racism, and (d) that under certain historical and political conditions members of social categories and groups may contest their essentialized identity, such as parts of the feminist movement, or that they may attempt to reconstruct an essentialized identity, such as parts of the homosexual movement or the largely defunct European nobility. Besides explicit political and power interests, we see communication processes and language use as a tacit force driving essentialization of social categories.
Bhaskar and Bunge on Social Emergence
Authors: KAIDESOJA TUUKKA
Published: March 2009

This article discusses the theories of social emergence developed by Roy Bhaskar and Mario Bunge. Bhaskar's concept of emergent causal power is shown to be ambiguous, and some of the difficulties of his depth‐relational concept of social emergence are examined. It is argued that Bunge's systemic concept of emergent property is not only different, but also clearer and more consistent than Bhaskar's concept of emergent causal power. Despite its clarity and consistency, Bunge's definition of the concept of emergent property is shown to be too broad and analytically imprecise for the purposes of an emergentist social ontology. It is argued that Bunge's systemic account of social emergence can be developed further by using William Wimsatt's gradual approach to emergent phenomena and his four conditions of aggregativity of a systemic property. It is shown that these conditions provide useful conceptual tools for clarifying and investigating different kinds of mechanisms of social emergence and developing stronger varieties of the concept of emergent social property than that indicated in Bunge's definition of this concept.
The growth, reproduction and mortality of an enclosed population of red deer (Cervus elaphus) in north‐west England
Authors: Goldspink C. R.
Published: March 2009

This paper considers the growth, reproduction and mortality of enclosed (400 years) red deer, Cervus elaphus L. (n= 250–300), in Lyme Park, Cheshire, England. The Park consists of woodland (116 ha), parkland (175 ha) and moorland (244 ha) habitats. It was privately owned until 1946. Culling to control deer numbers was first done in 1975, and these results cover the period 1975–83.

Stags and hinds were locally abundant. Densities of hinds varied from 30 km−2 in the park to 77 km−2 on the moor. Three bachelor herds of stags were present but overall the population was dominated by hinds (sex ratio > 3:1). Performance was generally unexceptional for this species in Britain. Growth rates of stags and hinds were especially poor on the moor (to 400 m). Calf to hind ratios were generally low (range 0‐20‐0‐34) but maxima (0.55–0.60) were recorded in woodland sites.

Conditions on the moor were severe during the winter due to the poor quality of herbage (Molinia dominated) and a lack of shelter. Calf mortality (1975–83) varied (10–30%) but was particularly high during the cold winters of 1978–79 and 1981–82. Population density and winter food were probably the two principal factors limiting the performance of deer on the moor. By contrast, growth rates of stags and hinds in the park were high. However, calf to hind ratios were surprisingly low (0.15–0.26). No explanation of this anomally was apparent but the effects of ‘stress’ cannot be ruled out. Parkland stags dominated the rut throughout the whole Park because of their superior size and status. Stags from the moor appeared to play no part in the rut.

Culling has reduced levels of natural mortality but further improvements in performance are unlikely to be achieved without a reduction in sheep stocks, some improvement in habitat and the provision of shelter. There may, however, be some merit in retaining a high population density in Lyme Park for conservation reasons. Parks provide unique opportunities for studying the behaviour and ecology of red deer. The effects of competition, parental investment and management can be studied without the inconvenience of immigration or emigration. The problems of managing small populations of deer are briefly discussed.
Podocytes in the axial organ of echinoderms
Authors: Welsch U. , Rehkämper G.
Published: March 2009

The axial organ of two sea urchin genera, Echinometra and Eucidaris, has been analysed with the electron microscope. It is mainly built up by an extracoelomic tissue rich in various leucocytic cells and blood vessels lacking an endothelium. The axial sinus (axocoel) is located on the interior of the axial organ, and evaginations extend into this loosely constructed tissue. The epithelium of the axial sinus and its extensions are characterized by epitheliomuscular cells and abundant podocytes, which overlie the blood vessels. Since podocytes are the well known structural basis for ultrafiltration, it is postulated that this is a function of the axial organ at least in echinoids and asteroids.
Jaw movements from microwear on the molar teeth of the koala Phascolarctos cinereus
Authors: Young W. G. , Robson S. K.
Published: March 2009

To study the direction of jaw movements in the koala from wear facets on the molar teeth by scanning electron microscopy, gold coated epoxy resin replicas from the right maxillary and mandibular tooth quadrants were examined from 12 koala skulls. The progressive development and location of facets, the orientation of striae on them and directional data were recorded and transferred from electron micrographs to superimposable transparencies.

Polished facets with laterally oriented striations developed on the cristids and cristae progressively into dentine, where Greaves' effect indicated that the direction of the chewing stroke was labiolingual. Polished and pitted facets, aligned and striated in the parasagittal plane, occurred on the smooth interactive enamel surfaces of maxillary and mandibular cusps.

Labiolingual transit of the crislids over the cristae, with a slight anteromedial shift, was inferred to be the predominant chewing stroke on the working side with no contralateral balancing contact. A propalinal isognathous movement in which successive cusps made contact was also deduced.

Previous concepts of koala chewing and tooth wear were confirmed and amplified, and these may have application to studies of extinct marsupial jaw mechanisms.
The calcified amorphous layer of the skin of Bufo marinus (Amphibia: Anura)
Authors: Sampson H. W. , Canon M. S. , Davis R. W.
Published: March 2009

The integument of Bufo marinus is surveyed. It is similar to that of other anurans and contains the three chromatophores common to anurans. The skin of these toads contains more than 28% minerals deposited as small crystals in a mucopolysaccharide‐positive amorphous layer between the stratum compactum and the stratum spongiosum. These crystals reveal a high content of calcium and phosphorus aggregated in and near membrane‐bound vesicles which have an appearance very similar to matrix vesicles. Electron microscopy gives the appearance that these vesicles are associated with flbroblasts located between alternating bundles of collagen. Histochemical studies indicate that the amorphous layer possesses many of the characteristics commonly associated with mineralized cartilage or bone.
Activity and thermoregulation of the snake Natrix maura. 1. r and K thermoregulation
Authors: Hailey A. , Davies P. M. C.
Published: March 2009

Natrix maura was active by day and night throughout its annual activity season (March to October), with body temperatures (Tb) between 14–35 C. Body temperatures during foraging (aquatic, for fish) were constrained by water temperature. Snakes also raised Tb by basking. Basking in the laboratory was analysed by fitting logistic curves to heating rates, and determining half times (HT) as a descriptive statistic. Snakes in the field often basked for much longer than necessary to reach an equilibrium Tb; these basking times often exceeded HT more than ten‐fold. This led to the concept of two strategies of thermoregulation, here designated r‐thermoregulation and K‐thermoregulation.

In r‐thermoregulators the heating rate, r, is maximized until the preferred Tb is reached, and then the behaviour for which the high Tb has been achieved is pursued. The advantage of high Tb is short term, usually for increased performance during foraging. This is the commonly studied form of thermoregulation, and is typical of the behaviour of small lizards where it leads to a shuttling pattern of activity, r thermoregulation is usually by basking.

In K thermoregulators an equilibrium Tb, K*, is reached and maintained for long period. K* may be lower than the equilibrium of logistic heating in the conditions, K, if this is too hot. The behaviour of N. maura was often consistent with this pattern; the snakes moved into shade while basking, and at air temperatures above 26 C most of the body was in shade. Increasing the rate of longer term physiological processes, such as maturation of reproductive products or (as in N. maura) rate of digestion, are the benefit of maintaining K*. K thermoregulation is by basking or thigmothermy.
The activity patterns of the Pyrenean desman (Galemys pyrenaicus) (Insectivora: Talpidae), as determined under natural conditions
Authors: Stone R. D.
Published: March 2009

The activity patterns of free‐ranging desmans (Galemys pyrenaicus) on three streams in the French Pyrenees were investigated. Data were obtained using an automatic radiotracking system to monitor an animal's presence at, or absence from, its nest site. Individuals displayed two distinct periods of activity during each diel period throughout this study (May–July), a short diurnal period of activity and a longer nocturnal one. The daily onset and cessation of activity for all desmans on each stream was highly synchronized. These findings are discussed with relation to prey availability and the social ecology of the species.
The life cycle of the Acari Tyrophagus similis
Authors: Al‐Safadi M. M.
Published: March 2009

Tyrophagus similis Volgin can complete a generation in about 11 days under normal conditions. Fertilized females deposit an average of 18 eggs, with a maximum number laid by any one female of 36 eggs. No hypopus appears to exist during the life cycle. There is a positive correlation between Gamasellodes/Protogamasellus species (predator) and Tyrophagus similis. The mite can feed on plant and animal debris.
Sexual dimorphism in the pelvic bones of Svalbard reindeer, Rangifer tarandus platyrhynchus
Authors: Tyler N. J. C.
Published: March 2009

The determination of sex of carcasses of reindeer and caribou (Rangifer tarandus) is complicated because both sexes normally carry antlers. Growth curves of males and females diverge sufficiently so that the length of long bones can often indicate the sex of a carcass if its age at death is known; results, however, are not always conclusive. Pronounced sexual dimorphism was found in the breadth of the ventro‐medial border (rim) of the acetabulum of adult Svalbard reindeer. Measurement of the rim of the acetabulum thus provides a quick and conclusive means for determining the sex of carcasses of these animals. Similar results have been found in several other species of ungulates. Reasons for the dimorphism and for the non‐normal distribution of the data for both sexes in reindeer are discussed.
The copulation of a linyphiid spider, Baryphyma pratense: does a female receive a blood‐meal from her mate?
Authors: Blest A. D.
Published: March 2009

Blest & Taylor (1977) noted that when the cephalic sulci of male Baryphyma pratense (Blackwall) are gripped by the fangs of females during copulation, the male heads bleed and the females ingest the blood. It has recently been suggested by Schaible, Gack & Paulus (1986) that ‘blood’ may in fact have been the secretion from the cephalic glands associated with the sulci. The early account is expanded, and the reasons for supposing the material to be haemolymph listed. Cephalic bleeding by males of B. pratense is suggested to be unusual, and to represent both a bizarre variant of courtship feeding, and a form of male parental investment.
Forces exerted on the ground by galloping dogs (Canis familiaris)
Authors: Bryant J. D. , Bennett M. B. , Brust J. , Alexander R. McN.
Published: March 2009

In quadrupedal galloping, one foot of each pair (the ‘trailing’ foot) is set down shortly before the other (‘leading’) foot. Alexander, Jayes & Ker (1980) argued that the trailing and leading feet should exert different patterns of force on the ground, to make the most effective use of tendon elasticity to reduce the energy cost of locomotion. We have used two force plates mounted in tandem in a playing field to obtain records of the forces exerted by individual feet of galloping dogs. We find that the patterns of force exerted by trailing and leading feet are much more similar than had been predicted.
Sebum‐storing flank gland hairs of the musk shrew, Suncus murinus viridescens
Authors: Balakrishnan M.
Published: March 2009

Lipid droplets discharged from the disintegrating holocrine cells of the flank gland of the Indian musk shrew, Suncus murinus viridescens (Blyth) are stored in the lumen of the sebaceous acini and eliminated to the exterior through the glandular ducts. Specialized hairs developed on the surface of the flank gland of the shrew are deep rooted. The osmetrichia of the flank gland of both sexes of the shrew have flattened and thickly packed culicular scales. These scales are morphologically different from the largeconical‐shaped scales of the dorsal body hairs. The surface of osmetrichia is soaked with the oily secretory materials of the flank gland. The medulla of osmetrichia is developed into Special chambers which are filled with the glandular secretory droplets.
The role of the coelom as a hydrostatic skeleton in lingulid brachiopods
Authors: Trueman E. R. , Wong T. M.
Published: March 2009

Anatomical and experimental studies of the perivisceral coelom and pedicel ofLingula ana linaindicate that the coelomic fluid functions as a hydrostatic skeleton in respect of valve and pedicel movements, valve opening always being associated with positive pressures. The perivisceral coelom is surrounded by a body wall containing circumferential muscle fibres, whilst all muscles passing between the valves (principally adductor and oblique fibres) are located within the body wall. These two sets of muscles function similarly to the circular and longitudinal muscles of a classical hydrostatic skeleton.

Pressure recordings from the lumen of the pedicel and perivisceral coelom, during opening or rotary movements of the valves, were similar and showed pressure pulses of up to 0.8 kPa. During the initial stages of burrowing, pulses of up to 2.5 kPa were observed when the valves were being pressed into the sand. These values are well within the capability of the circumferential muscles of the body wall.
Biomechanical limits to ecological performance: mollusc‐crushing by the Caribbean hogfish, Lachnolaimus maximus (Labridae)
Authors: Wainwright Peter C.
Published: March 2009

Functional limitations on feeding ability were investigated in the mollusc‐crushing Caribbean hogfish, Lachnolaimus maximus (Labridae). Two constraints were proposed to limit the maximum size prey L. maximus can eat: pharyngeal jaw gape and crushing force. These factors yield diflferent quantitative expectations for the relationship between fish size and maximum prey size. Their relative importance for predation on a frequently consumed gastropod (Cerithium litteratum) was investigated in laboratory performance tests designed to determine the largest snails fish could eat. Cerithium predation was found to be force limited rather than gape limited. The importance of this functional constraint in determining the largest Cerithium consumed by wild fish was examined by comparing hogfish feeding capability, as determined by the performance tests, to the maximum size snails found in the stomach contents of field‐collected fish. Crushing ability appears to limit Cerithium predation in natural fish populations. The utility of performance testing for determining the functional and ecological importance of morphology is discussed.
Spool‐and‐line tracking of giant rats in New Guinea
Authors: Berry A. J. , Anderson T. J. C. , Amos J. N. , Cook J. M.
Published: March 2009

We present movement data for a species of New Guinea “giant rat”, Mallomys rothschildi, as a test of the efficacy of a recently developed method of spool‐and‐line tracking in short‐term ecological/behavioural studies. We demonstrate that M. rothschildi is scansorial, feeds on shoots of Pandanus spp., and ranges freely over large areas without apparently being constrained by a fixed “home” nest. Another species, Hyomys golialh, occurs sympatrically and is superficially virtually indistinguishable from M. rolhschildi. Data from the single individual tracked suggest that the two species are ecologically segregated on the basis of clear behavioural differences. We note the considerable advantages of spool‐and‐line tracking over radio tracking in this type of study.
Cranial anatomy of some Indian cynoglossids: A study in adaptation. Part III. Ligaments
Authors: Das M. , Datta N. C.
Published: March 2009

Ligaments associated with the jaws. and suspensorium are relatively well developed on the blind side. Maxilla‐ethmoid, maxilla‐mandible, autopalatine‐maxilla, pterygoid‐lateral ethmoid and pterygoid‐prevomer ligaments are present only on the blind side. The asymmetrical nature and disposition of ligaments enable the jaws of the blind side to feed effectively.
Active and resting metabolism in birds: allometry, phylogeny and ecology
Authors: Bennett P. M. , Harvey P. H.
Published: March 2009

Variation in resting metabolic rate is strongly correlated with differences in body weight among birds. The lowest taxonomic level at which most of the variance in resting metabolic rate and body weight is evident for the sample is among families within orders. The allometric exponent across family points is 0.67. This exponent accords with the surface area interpretation of metabolic scaling based on considerations of heat loss. Deviations of family points from this allometric line are used to examine how resting metabolic rates differ among taxa, and whether variation in resting metabolic rate is correlated with broad differences in ecology and behaviour. Despite the strong correlation between resting metabolic rate and body weight, there is evidence for adaptive departures from the allometric line, and possible selective forces are discussed.

The allometric scaling of active metabolic rate is compared with that of resting metabolic rate. The allometric exponents for the two levels of energy expenditure differ, demonstrating that active small‐bodied birds require proportionately more energy per unit time above resting levels than do active large‐bodied birds. No consistent evidence was found to indicate that the different methods used to estimate active metabolic rate result in systematic bias. Birds require more energy relative to body size when undertaking breeding activities than at other stages of the annual cycle.
Past and present status of the southern elephant seal (Mirounga leonina) at Macquarie Island
Authors: Hindell M. A. , Burton H. R.
Published: March 2009

The southern elephant seal population at Macquarie Island has undergone a serious decline since regular surveys were commenced in 1949. Approximately 2,900 cows and 250 bulls were counted in the isthmus study area during the 1985 breeding season. Comparisons with 20 other counts made in the same area between 1949 and 1984 showed that, although there was considerable fluctuation between the years, the number of seals ashore has dropped at an average rate of 2.1% per year, resulting in a net decrease of approximately 50% for both males and females. This is similar to the ratio of decline of elephant seal populations in the southern Indian Ocean. The census information from all major elephant seal populations was reviewed and it was concluded that there may be a common factor, or group of factors, acting to reduce the Macquarie Island and Indian Ocean populations, while the populations of the South Atlantic seem to be stable. Several potential explanations for these observations are advanced, but it is concluded that a greater knowledge of the ecology of the seals is needed if the declines are to be understood.