bluuebunny/crossref_metadata_2025 huggingface dataset:
A Pascal implementation of the GSPC Core Graphics package
Authors: Nicol C. J. , Kilgour A. C.
Published: November 2005

A level 3 Pascal implementation is described of the original Core Graphics package proposed by the Graphics Standards Planning Committee of the ACM in 1977 [1]. The implementation was carried out as a team project by a group of final year Computing Science undergraduates, using a general-purpose mainframe (ICL 2976) with a large virtual address space. The available Pascal compiler recognised up to 32 significant characters in identifier names, which permitted the procedure names suggested in the specification to be used unmodified. The paper discusses the factors affecting the choice of language, the ease of use of the Core definition as a working document, and the success of the project both as an educational exercise and as an evaluation of the Core proposal.
Computer-aided definition, manipulation and depiction of objects composed of spheres
Authors: Knowlton K.
Published: November 2005

As previously demonstrated by Badler and O'Rourke, a variety of 3-D objects can be defined conveniently as collections of spheres-having various sizes and positions in 3-D space and possibly intersecting. This paper is an elaboration on the technique, describing methods of constructing and manipulating such objects and, most particularly, a method of achieving realism in rendering the picture-even though, for reasons of efficiency, computation is performed as if everything were 2-dimensional, with depth ordering.Pictorial realism results from three features of the overall method:
roundedness
of the basic picture plane images of individual spheres, pictorial
merging
of 3-dimensionally intersecting spheres (which are very likely intended as parts of the same object), and pictorial
separation
of spheres whose images overlap but which lie at significantly different depths in 3-space. Separation is achieved by a black line and resembles the lines traditionally found in cartoon cel animation; merging is accomplished by arranging, in effect, for every sphere image to be transparent to the brighter parts of images of other spheres of the same color.The system lends itself well to construction and manipulation of objects defined by geometry and mathematical transformations; it also serves well in construction and depiction of organic forms which arise and/or are modified by random growth and rules of contingency. Several examples of pictorial results are presented.
A multi-processor system for hidden-surface-removal
Authors: Chang P. , Jain Ramesh
Published: November 2005

Hidden-surface algorithms have attracted many researchers interested in creating realistic images. Many algorithms have been developed for hidden-surface removal. Different forms of "coherences" are used in order to reduce the computing required to generate a realistic image without hidden surfaces. We propose a hidden-surface removal system which uses many loosely coupled processors connected in parallel. All processors execute the same code while concurrently working on different portions of the screen. The original scene is partitioned in n equal segments, where n is the number of processors. Each processor works on a specified window of the scene. This requires additional clipping operations for each processor. Also, as the screen is partitioned into many disjoint areas, any "coherence" used by the hidden-surface algorithm is lost. Thus, each processor has to reset its segment list. The above options result in more work for each processor, limiting the gain in speed expected by displaying several processors.This scheme has been simulated for different types of scenes using 2, 4, 8 and 16 processors. Our simulation study shows that for lower values of n, the clipping time is much lower than the hidden-surface-removal time for a processor. For more than 16 processors, the clipping time is comparable to, or more than, the hidden-surface-removal time. We discuss implications of the partitioning of the scene and discuss methods to improve the scheme by using a superviser to utilize all processors efficiently.The proposed system will be very useful in many interactive graphics applications requiring fast display of realistic images.
Real-time raster scan unit with improved picture quality
Authors: Piller Ernst , Widner Herbert
Published: November 2005

The raster-scan unit described below was planned with the intention of fulfilling all important requirements of graphical output units. The emphasis lies on the discription of the algorithms and the hardware necessary for generating vectors and circles, including intensity variation. This device is characterized by the real-time conversion of all picture elements.
Position paper on graphics standards
Authors: Vinberg Anders
Published: November 2005

This paper describes the position on standardization of computer graphics held by Integrated Software Systems Corporation (ISSCO), the producers of the DISSPLA and TELL-A-GRAF systems. In brief ISSCO is strongly favorable to the idea of standardization; however, ISSCO feels that the "Core" proposal produced by the GSPC has some deficiencies, serious enough to severely limit its utility; and ISSCO fears that these deficiencies may be caused by the domination of the standardization effort by experts from certain application areas.This paper discusses the philosophy and emphasis of the current work on standardization, and goes on to describe in detail some of the problems with the Core proposal. An approach to a solution of the problems is also discussed.
An improved economic design for a display processor intermixing refresh and storage graphics
Authors: Feenstra Jelte , van den Bos Jan
Published: November 2005

Several designs have tried to capitalize on the rudimentary refresh-capabilities of the Tektronix 4014/4015 display terminal by augmenting the hardware with a microprocessor and program and display memory. This paper scrutinizes the existing implementations and offers an alternative based on a Zilog Z80 as the heart of the display processor, a direct-memory access channel to the display terminal for picture data transfer, and a parallel I/O interface between display processor and host computer. In a second stage this alternative will be extended with hardware to support coordinate transformations. This hardware is centered around an AM2903 bit-sliced microprocessor. This collection of hardware enhancements is such that the shortcomings in most existing designs are circumvented and the load on the host computer is minimized. It provides flexible refresh capabilities with selective update, limited possibilities for matrix transformation, as well as display support for storage graphics, at affordable prices.
Interactive computer graphics with the UNIX time-sharing system
Authors: Ferrin Thomas E. , Langridge Robert
Published: November 2005

The UNIX† time-sharing system is a powerful and efficient multiuser operating system possessing many unique and attractive advantages. In order to fully support an interactive graphics facility, however, several minor extensions were made to provide the necessary high performance 'real-time' environment. These enhancements to the UNIX system are described together with the implementation details for the Picture System 2 Graphic Subroutine Package.
The scope of motion research
Authors: Tsotsos John K.
Published: November 2005

This paper will attempt to briefly outline the broad scope of research endeavours that involve visual temporal change. It is acknowledged that several classes of researchers with differing backgrounds such as psychophysics and neurophysiology, as well as computer vision, artificial intelligence and computer graphics, are active in the area of motion research, and that their interaction may be of benefit. In general terms, these endeavours are those of quantification of intensity changes in image sequences, representation of visual temporal information, temporal reasoning and event description, motion generation, animation, control structures for coordinating the above into a unified computer system whether it be a vision system or an animation system, and studies of biological visual systems, both psychophysical and neurophysiological. Motion understanding will be briefly described in terms of its three main components: sensing motion, perception, interpretation and description of motion; and, motion generation. In an attempt to deal with the complexity of complete motion understanding systems, hypotheses and models will be drawn from the vast literature available in some of these different classes, although by necessity, this discussion will be short and limited.
Real and apparent motion
Authors: Green Marc , von Grunau Michael
Published: November 2005

Two direction selective adaptation experiments were conducted to investigate whether real and apparent motion are processed by a single visual mechanism. Previous studies with real motion have shown that adaptation to a grating drifting in one direction has an effect on perceived motion of subsequently viewed test gratings (the velocity aftereffect) and also selectively raises contrast threshold (direction-specific threshold elevation). We conducted analogous experiments in which observers adapted to real motion but were tested with apparent motion. In the "velocity aftereffect" study, we found that adaptation to real motion had a profound effect on the strength of apparent motion, suggesting a single mechanism. However, it was found in a second experiment that although adaptation to a moving grating produced a direction selective effect on
perception
of apparent motion, there was no direction selective threshold elevation for
detection
of the test stimuli. We conclude that although a single mechanism is responsible for mediate conscious motion perception, detection of objects in real and apparent motion is performed by two separate mechanisms.
Complex logarithmic mapping and the focus of expansion (abstract only)
Authors: Jain Ramesh
Published: November 2005

Complex logarithmic mapping has been shown to be useful for the size, rotation, and projection invariance of objects in a visual field for an observer translating in the direction of its gaze. Assuming known translational motion of the observer, the ego-motion polar transform was successfully used in segmentation of dynamic scenes. By combining the two transforms one can exploit features of both transforms and remove some of the limitations which restrict the applicability of both. In this paper we show that by using complex logarithmic mapping with respect to the focus of expansion rather than the center of the visual field perfect projection invariance and better size and rotation invariance may be obtained for any arbitrary motion of the observer.
The cross-ratio and the perception of motion and structure (abstract only)
Authors: Simpson William A.
Published: November 2005

Followers of J. J. Gibson have proposed that the cross-ratio, a projective invariant for four collinear points, underlies the perception of objects in motion. Experiment 1 tested this theory by presenting subjects with displays of 3 or 4 dots rotating in depth. Accuracy was equally high in both conditions for motion and structure judgements, so the cross-ratio cannot be necessary. Experiments 2 and 3 tested the cue of lining up, and some evidence for its use was found. The results are consistent with an analysis based on the sinusoidally changing positions of the dots.
Representing and reasoning about change (abstract only)
Authors: Simmons Reid G. , Davis Randall
Published: November 2005

A recent trend in artificial intelligence research is the construction of expert systems capable of reasoning from a detailed model of the objects in their domain and the processes that affect those objects. We describe a system being built in this fashion, designed to solve a class of problems known as geologic interpretation: given a cross-section of the Earth's crust (showing formations, faults, intrusions, etc.), hypothesize a sequence of geologic events whose occurrence could have formed that region. Solving the geologic interpretation problem requires reasoning about change, in particular, spatial change. The shape of a formation, for example, can be altered by the process of erosion. Doing this reasoning, in turn, requires representing objects, which show the effects of change, and processes, which are the causes of those changes.The main focus of this research is to explore the machinery needed to represent and reason about both mutable objects and the processes that induce changes in them. To do this, we have developed two representations of objects, one involving
histories
and the other involving
diagrams
. We have also developed two corresponding representations of physical processes, each suited to reasoning about one of the object representations. We have been careful to keep the two representations well separated, limiting their interaction to a relatively small and dearly defined interface.We have used these representations to model a subset of geology large enough to allow us to solve most geologic interpretation problems. In particular, the model allows us to
imagine
a sequence of geologic events.
Imagining
is a new form of qualitative simulation similar to
envisioning
.
Geographic data bank
Authors: Bribiesca Ernesto , Torres Hugo D.
Published: November 2005

The system comprises geographic information of Topographic, Geologic, Soils distribution, Present land use, Potential land use and Climatic charts produced by CETENAL and a set of programs written in FORTRAN IV, including a flexible access language easy to master. It is therefore a Geographic Data Bank, whose information may be consulted and manipulated by many kinds of users. It is possible to improve and update the CDB (CENTENAL'S Data Bank). The CDB is of great help in planification projects directed towards the control of the development of our nation.
A graphics subroutine package for the Neuroscience Display Processor
Authors: McInroy John W. , Capowski Joseph J.
Published: November 2005

The Neuroscience Display Processor (NDP) has been developed at the University of North Carolina for displaying two- and three-dimensional structures, and two-dimensional graphs. To make easy the displaying of graphs and other drawings on a refresh CRT or on a digital plotter, a subroutine package has been produced for the scientist programming in FORTRAN. Various levels of access (implemented as levels in a hierarchy of subroutines) provide increasing flexibility at the cost of increasing programming complexity. At the highest level, and with the least effort (i.e., with a single subroutine call), a programmer may display a graph accompanied by coordinate axes with scales, a title, and axis labels. The programmer may optionally display two such graphs on the CRT simulataneously. He may also display several graphs on the same set of coordinate axes. Graphs may be displayed without coordinate axes, etc., to facilitate the drawing of many superimposed graphs on hard copy.An NDP daslgn assumption that the general-purpose computer refreshes the CRT has far-reaching effects on the software design. That assumption, space and time constraints, the use of FORTRAN, and the provision of various options appropriate for the area of application all result in the programmer's being provided with a single subroutine to be called inside a refresh loop, with many switches as parameters.Where the needs of the application are not net by the capabilities aentloned above, the programmer may replace the single subroutine call by the use of several subroutines at lower levels as building blocks, with which to construct his own graphs or other drawings, thereby sacrificing some ease of programming for increased flexibility. The programmer nay call a subroutine to display a real number or an integer at a specified spot on the screen. He may display a character string. At a still lower level, the programmer say call for the display of a single character. At the lowest level of FORTRAN call, the programmer may specify that either polygons or series of disconnected lines or dots be drawn, nay indicate whether they are to be drawn on the CRT or on the plotter, and may load the rotation-and-translation matrix of the NDP.
Dispatching by graphical terminals
Authors: Niemeyer G.
Published: November 2005

Based on IBM's Geo-Data Analysis and Display System (GADS) a simulation model for interactive dispatching in a geographic area has been developed. This model permits either multiple assignments of many service units to one call for service or tour building for one service unit to many calls for service. The motion of service units can be monitored on the sreen and the assignments and tours, respectively, may be modified dynamically.The simulation model is primarily intended to be a step towards a real computer assisted dispatching system. This system is to be feed with the coordinates and data of the calls for service and with the moving coordinates of the service units from outside (e.g. by automatic telephone line identification and by radio). Furthermore this system has to inform the service units automatically (e.g. by radio) of the dispatching decisions relating to them.
Raytracing irregular volume data
Authors: Garrity Michael P.
Published: November 2005

An efficient technique is described for rendering volume data which is not organized as a regular, three-dimensional grid. The algorithm works on collections of convex cells with shared faces. Datasets of this form are quite common in such applications as Computational Fluid Dynamics (CFD) and Finite Element Modeling (FEM).
A polygonal approximation to direct scalar volume rendering
Authors: Shirley Peter , Tuchman Allan
Published: November 2005

One method of directly rendering a three-dimensional volume of scalar data is to project each cell in a volume onto the screen. Rasterizing a volume cell is more complex than rasterizing a polygon. A method is presented that approximates tetrahedral volume cells with hardware renderable transparent triangles. This method produces results which are visually similar to more exact methods for scalar volume rendering, but is faster and has smaller memory requirements. The method is best suited for display of smoothly-changing data.
An efficient method for volume rendering using perspective projection
Authors: Novins Kevin L. , Sillion Francois X. , Greenberg Donald P.
Published: November 2005

Use of the perspective projection adds important perceptual cues for image comprehension. However, it has not been widely used in volume rendering because of the lack of efficient computational algorithms and concern over the nonuniform sampling rate imposed by perspective ray divergence. This paper introduces two new techniques to help make perspective projection more feasible in rendering volume data. First, a method is presented for efficient slice-by-slice processing of volume data, allowing high resolution data sets by eliminating typical memory constraints. Second, an adaptive "ray splitting" approach is described which ensures that the entire volume is sampled within user-specified limits. Additionally, we present results using distributed ray tracing to achieve depth of field effects.
Charting a global future for education in physiology
Authors: Sefton Ann J.
Published: November 2005

The 2005 Claude Bernard Distinguished Lecture was presented at the XXXV International Congress of Physiological Sciences (IUPS) in San Diego, CA, by Ann J. Sefton. Dr. Sefton is an Emeritus Professor of Physiology of the University of Sydney and co-Chair of the IUPS Education Committee. A full profile of Dr. Sefton is included in this issue’s The Physiology Teacher.
Using student feedback to construct an assessment rubric for a concept map in physiology
Authors: Moni Roger W. , Beswick Eileen , Moni Karen B.
Published: November 2005

Constructing quality assessment rubrics can be challenging, especially when they are used for integrated, group-centered, applied learning. We describe a collaborative assessment task in which groups of second-year dentistry students developed a complex concept map. In groups of four, the students were given a written, simulated, medical history of a patient and required to construct a concept map illustrating relevant pathophysiological concepts and pharmacological interventions. This report describes a research project aimed at making educational goals of the task more explicit through investigating student and faculty member understandings of the criteria that might be used to assess the concept map. Information was gathered about the perceptions of students in relation to the learning goals associated with the task. These were compared with faculty member perceptions. The findings were used to develop an assessment rubric intended to be more accessible to learners. The new rubric used the language of both faculty members and students to more clearly represent expectations of each criterion and standard. This assessment rubric will be used in 2005 for the next phase of the project.
Estradiol-17β stimulates proliferation of mouse embryonic stem cells: involvement of MAPKs and CDKs as well as protooncogenes
Authors: Han Ho Jae , Heo Jung Sun , Lee Yun Jung
Published: November 2005

Although the importance of estradiol-17β (E2) in many physiological processes has been reported, to date no researchers have investigated the effects of E2 on embryonic stem (ES) cell proliferation. Therefore, in the present study, we have examined the effect of E2 on the DNA synthesis of murine ES (ES-E14TG2a) cells and its related signaling pathways. The results of this study show that E2 (10−9 M) significantly increased [3H]thymidine incorporation at >4 h and that E2 (>10−12 M) induced an increase of [3H]thymidine incorporation after 8-h incubation. Moreover, E2 (>10−12 M) also increased 5′-bromo-2′-deoxyuridine (BrdU) incorporation and cell number. Indeed, E2 stimulated estrogen receptor (ER)-α and -β protein levels and increased mRNA expression levels of protooncogenes (c- fos, c- jun, and c- myc). Tamoxifen (antiestrogen) completely inhibited E2-induced increases in [3H]thymidine incorporation. In addition, estradiol-6- O-carboxymethyl oxime-BSA (E2-BSA; 10−9 M) increased [3H]thymidine incorporation at >1 h, and E2-BSA (>10−12 M) increased [3H]thymidine incorporation after 1-h incubation. E2-BSA-induced increase in BrdU incorporation also occurred in a dose-dependent manner. Tamoxifen had no effect on E2-BSA-induced increase of [3H]thymidine incorporation. Also, E2 and E2-BSA displayed maximal phosphorylation of p44/42 MAPKs at 10 and 5 min, respectively. E2 increased cyclins D1 and E as well as cyclin-dependent kinase (CDK)2 and CDK4. In contrast, E2 decreased the levels of p21cip1 and p27kip1 (CDK-inhibitory proteins). Increases of these cell cycle regulators were blocked by 10−5 M PD-98059 (MEK inhibitor). Moreover, E2-induced increase of [3H]thymidine incorporation was inhibited by PD-98059 or butyrolactone I (CDK2 inhibitor). In conclusion, estradiol-17β stimulates the proliferation of murine ES cells, and this action is mediated by MAPKs, CDKs, or protooncogenes.
Heme oxygenase-1 mediates the anti-inflammatory actions of 2′-hydroxychalcone in RAW 264.7 murine macrophages
Authors: Abuarqoub Hadil , Foresti Roberta , Green Colin J. , Motterlini Roberto
Published: November 2005

Chalcones are a group of plant-derived polyphenolic compounds that belong to the flavonoids family, and possess a wide variety of cytoprotective and modulatory functions. Chalcones exert their cytoprotective actions via activation of specific transcriptional factors and upregulation of endogenous defensive pathways, such as phase II enzymes and the stress protein heme oxygenase-1 (HO-1). In this study, we investigated the anti-inflammatory action of 2′-hydroxychalcone (2-HC) in a model of lipopolysaccharide (LPS)-induced inflammation in RAW 264.7 macrophages and examined the role of HO-1 in this process. Our results demonstrate that 2-HC potently induces HO-1 expression and markedly reduces LPS-mediated nitrite and TNF-α production. These effects are accompanied by inhibition of inducible nitric oxide synthase protein expression and abolished by blockade of heme oxygenase activity with either tin protoporphyrin IX or HO-1 small interfering RNA. By using a pharmacological approach and siRNA technology, we also found that phosphatidylinositol 3-kinase is a major cellular mediator in 2-HC-induced HO-1 expression. These findings strongly suggest that 2-HC exerts anti-inflammatory actions via activation of the HO-1 pathway and help to elucidate the mechanisms underlying the potential therapeutic value of chalcones.
Inhibition of AIF-1 expression by constitutive siRNA expression reduces macrophage migration, proliferation, and signal transduction initiated by atherogenic stimuli
Authors: Tian Ying , Kelemen Sheri E. , Autieri Michael V.
Published: November 2005

Allograft inflammatory factor-1 (AIF-1) is a cytoplasmic, calcium-binding, inflammation-responsive scaffold protein. Several studies have reported increased AIF-1 expression in activated macrophages and have implicated AIF-1 as a marker of activated macrophages. However, the function of AIF-1 in macrophages and the mechanism whereby it participates in macrophage activation are unknown at this time. Immunohistochemical analysis colocalized AIF-1 expression with CD68-positive macrophages in atherosclerotic human coronary arteries. Subsequent experiments were designed to determine a role for AIF-1 in macrophage activation in response to atherogenic stimuli. Stimulation of human and murine macrophages with oxidized LDL significantly increased AIF-1 expression above basal levels. Stable transfection of AIF-1 small interfering RNA (siRNA) in macrophages reduced AIF-1 protein expression by 79% and reduced macrophage proliferation by 52% ( P < 0.01). Inhibition of proliferation was not due to induction of apoptosis. Sequences that did not knock down AIF-1 expression had no effect on proliferation. AIF-1 siRNA expression reduced macrophage migration by 60% ( P < 0.01). Both proliferation and migration of siRNA-expressing macrophages could be restored by adenoviral expression of AIF-1 ( P < 0.001 and 0.005, respectively), suggesting a tight association between AIF-1 expression and macrophage activation. Phosphorylation of Akt, p44/42 MAPK, and p38 kinase were significantly reduced in siRNA macrophages challenged with oxidized LDL ( P < 0.05). Phosphorylation of p38 kinase was significantly inhibited in siRNA macrophages stimulated with T lymphocyte conditioned medium ( P < 0.05). These data indicate that AIF-1 mediates atherogenesis-initiated signaling and activation of macrophages.
Effect of reduced oxygen tension on chondrogenesis and osteogenesis in adipose-derived mesenchymal cells
Authors: Malladi Preeti , Xu Yue , Chiou Michael , Giaccia Amato J. , Longaker Michael T.
Published: November 2005

Recent studies have demonstrated that adipose-derived mesenchymal cells (AMCs) offer great promise for cell-based therapies because of their ability to differentiate toward bone, cartilage, and fat. Given that cartilage is an avascular tissue and that mesenchymal cells experience hypoxia during prechondrogenic condensation in endochondral ossification, the goal of this study was to understand the influence of oxygen tension on AMC differentiation into bone and cartilage. In vitro chondrogenesis was induced using a three-dimensional micromass culture model supplemented with TGF-β1. Collagen II production and extracellular matrix proteoglycans were assessed with immunohistochemistry and Alcian blue staining, respectively. Strikingly, micromasses differentiated in reduced oxygen tension (2% O2) showed markedly decreased chondrogenesis. Osteogenesis was induced using osteogenic medium supplemented with retinoic acid or vitamin D and was assessed with alkaline phosphatase activity and mineralization. AMCs differentiated in both 21 and 2% O2environments. However, osteogenesis was severely diminished in a low-oxygen environment. These data demonstrated that hypoxia strongly inhibits in vitro chondrogenesis and osteogenesis in AMCs.
Atrial natriuretic peptide stimulates lipid mobilization during repeated bouts of endurance exercise
Authors: Moro Cédric , Polak Jan , Hejnova Jindra , Klimcakova Eva , Crampes François , Stich Vladimir , Lafontan Max , Berlan Michel
Published: November 2005

Atrial natriuretic peptide (ANP) controls lipolysis in human adipocytes. Lipid mobilization is increased during repeated bouts of exercise, but the underlying mechanisms involved in this process have not yet been delineated. The relative involvement of catecholamine- and ANP-dependent pathways in the control of lipid mobilization during repeated bouts of exercise was thus investigated in subcutaneous adipose tissue (SCAT) by microdialysis. The study was performed in healthy males. Subjects performed two 45-min exercise bouts (E1 and E2) at 50% of their maximal oxygen uptake separated by a 60-min rest period. Extracellular glycerol concentration (EGC), reflecting SCAT lipolysis, was measured in a control probe perfused with Ringer solution and in two other probes perfused with either Ringer plus phentolamine (α1/2-AR antagonist) or Ringer plus both phentolamine and propranolol (β-AR antagonist). Plasma epinephrine, plasma glycerol, and EGC were 1.7-, 1.6-, and 1.2-fold higher in E2 than in E1, respectively. Phentolamine potentiated exercise-induced EGC increase during E2 only. Propranolol reduced the lipolytic rate during both E1 and E2 compared with the probe with phentolamine. Plasma ANP concentration increased more during E2 than during E1 and was correlated with the increase in EGC in the probe containing phentolamine plus propranolol. The results suggest that ANP is involved in the control of lipolysis during exercise and that it contributes to stimulation of lipolysis during repeated bouts of exercise.
IL-1β directly excites isolated rat supraoptic neurons via upregulation of the osmosensory cation current
Authors: Chakfe Yassar , Zhang Zizhen , Bourque Charles W.
Published: November 2005

Previous studies have shown that IL-1β can excite the magnocellular neurosecretory cells (MNCs) of the hypothalamus. However, it is not known whether IL-1β can have direct IL-1 receptor type 1 (IL-1R1)-mediated effects on MNCs, and little is known about the cellular mechanisms by which IL-1β influences electrical activity in these cells. Here, we used patch-clamp recordings to examine the effects of IL-1β on acutely isolated rat MNCs. We found that IL-1β directly excites MNCs in a dose-dependent manner and that this response can be blocked by an inhibitor of the IL-1R1. Voltage-clamp analysis of the current evoked by IL-1β revealed a linear current-voltage relationship between −90 and −20 mV, and a reversal potential near −35 mV. This value was not affected by reducing the concentration of chloride ions in the external solution, indicating the involvement of a nonselective cation conductance. The effects of IL-1β were inhibited by Na-salicylate, an inhibitor of cyclooxygenase. Moreover. the effects of IL-1β were mimicked and occluded by PGE2, and were inhibited by AH-23848, an antagonist of the PGE2 type 4 (i.e., EP4) receptor. The current evoked by IL-1β was also abolished by 100 μM gadolinium (Gd3+), but was significantly larger when examined in cells preshrunk by negative pressure applied via the recording pipette. IL-1β alone did not cause changes in cell volume nor in the mechanosensitivity of MNCs. We conclude that IL-1β directly excites MNCs via an IL-1R1-mediated induction of PGE2 synthesis and EP4 receptor-dependent autocrine upregulation of the nonselective cation conductance that underlies osmoreception.
Gap Junctions Between Accessory Medulla Neurons Appear to Synchronize Circadian Clock Cells of the CockroachLeucophaea maderae
Authors: Schneider Nils-Lasse , Stengl Monika
Published: November 2005

The temporal organization of physiological and behavioral states is controlled by circadian clocks in apparently all eukaryotic organisms. In the cockroach Leucophaea maderae lesion and transplantation studies located the circadian pacemaker in the accessory medulla (AMe). The AMe is densely innervated by γ-aminobutyric acid (GABA)–immunoreactive and peptidergic neurons, among them the pigment-dispersing factor immunoreactive circadian pacemaker candidates. The large majority of cells of the cockroach AMe spike regularly and synchronously in the gamma frequency range of 25–70 Hz as a result of synaptic and nonsynaptic coupling. Although GABAergic coupling forms assemblies of phase-locked cells, in the absence of synaptic release the cells remain synchronized but fire now at a stable phase difference. To determine whether these coupling mechanisms of AMe neurons, which are independent of synaptic release, are based on electrical synapses between the circadian pacemaker cells the gap-junction blockers halothane, octanol, and carbenoxolone were used in the presence and absence of synaptic transmission. Here, we show that different populations of AMe neurons appear to be coupled by gap junctions to maintain synchrony at a stable phase difference. This synchronization by gap junctions is a prerequisite to phase-locked assembly formation by synaptic interactions and to synchronous gamma-type action potential oscillations within the circadian clock.
Embryonic lethality inDeargene-deficient mice: new player in angiogenesis
Authors: Herrera Victoria L. M. , Ponce Lorenz R. B. , Bagamasbad Pia D. , VanPelt Benjamin D. , Didishvili Tamara , Ruiz-Opazo Nelson
Published: November 2005

The dual endothelin-1/angiotensin II receptor (Dear) binds endothelin-1 (ET-1) and angiotensin II (ANG II) with equal affinities in the Dahl S/JRHSrat strain. To elucidate its physiological significance within the context of multiple receptor isoforms and diverse ET-1 and ANG II functions spanning blood pressure regulation, tumor proliferation, and angiogenesis, we characterized mouse Dear and Dear-deficient mice. Unlike null mutant models of ET-1, ANG II, and all other ET-1 and ANG II receptors, Dear−/−deficiency results in impaired angiogenesis, dysregulated neuroepithelial development, and embryonic lethality by embryonic day 12.5. Interestingly, mouse Dear does not bind ANG II, similar to Dahl R/JRHSrat Dear, but binds ET-1 and vascular endothelial growth factor (VEGF) signal peptide (VEGFsp) with equal affinities, suggesting a putative novel multifunction for VEGFsp and a parsimonious mechanism for coordination of VEGF-induced and Dear-mediated pathways. Consistent with its developmental angiogenic role, Dear inhibition results in decreased tumor growth in B16-F10 melanoma cell-induced subcutaneous tumor in female Dear+/−/C57BL6BC10mice, but not in males (age 3.5 mo), and in127Cs radiation-induced orthotopic mammary tumors in Sprague-Dawley female rats (age range 3–6.5 mo). Altogether, the data identify Dear as a new player in angiogenesis during development downstream to, and nonredundant with, VEGF-mediated pathways, as well as a putative modulator of tumor angiogenesis acting within a gender-specific paradigm.
Spontaneous Dynamics of Asymmetric Random Recurrent Spiking Neural Networks
Authors: Soula Hédi , Beslon Guillaume , Mazet Olivier
Published: November 2005

In this letter, we study the effect of a unique initial stimulation on random recurrent networks of leaky integrate-and-fire neurons. Indeed, given a stochastic connectivity, this so-called spontaneous mode exhibits various nontrivial dynamics. This study is based on a mathematical formalism that allows us to examine the variability of the afterward dynamics according to the parameters of the weight distribution. Under the independence hypothesis (e.g., in the case of very large networks), we are able to compute the average number of neurons that fire at a given time—the spiking activity. In accordance with numerical simulations, we prove that this spiking activity reaches a steady state. We characterize this steady state and explore the transients.
Classification of Faces in Man and Machine
Authors: Graf Arnulf B.A. , Wichmann Felix A. , Bülthoff Heinrich H. , Schölkopf Bernhard
Published: November 2005

We attempt to shed light on the algorithms humans use to classify images of human faces according to their gender. For this, a novel methodology combining human psychophysics and machine learning is introduced. We proceed as follows. First, we apply principal component analysis (PCA) on the pixel information of the face stimuli. We then obtain a data set composed of these PCA eigenvectors combined with the subjects' gender estimates of the corresponding stimuli. Second, we model the gender classification process on this data set using a separating hyperplane (SH) between both classes. This SH is computed using algorithms from machine learning: the support vector machine (SVM), the relevance vector machine, the prototype classifier, and the K-means classifier. The classification behavior of humans and machines is then analyzed in three steps. First, the classification errors of humans and machines are compared for the various classifiers, and we also assess how well machines can recreate the subjects' internal decision boundary by studying the training errors of the machines. Second, we study the correlations between the rank-order of the subjects' responses to each stimulus—the gender estimate with its reaction time and confidence rating—and the rank-order of the distance of these stimuli to the SH. Finally, we attempt to compare the metric of the representations used by humans and machines for classification by relating the subjects' gender estimate of each stimulus and the distance of this stimulus to the SH. While we show that the classification error alone is not a sufficient selection criterion between the different algorithms humans might use to classify face stimuli, the distance of these stimuli to the SH is shown to capture essentials of the internal decision space of humans.Furthermore, algorithms such as the prototype classifier using stimuli in the center of the classes are shown to be less adapted to model human classification behavior than algorithms such as the SVM based on stimuli close to the boundary between the classes.
Islamic Law and Environmental Ethics: How Jurisprudence (usul al-fiqh) Mobilizes Practical Reform
Authors: Jenkins Willis
Published: November 2005

Where some religious environmentalisms deploy traditional concepts according to the practical needs of cosmology, usul al-fiqh (jurisprudence) envisions an alternative practical strategy for Islamic environmental ethics. Jurisprudence governs religious adaptations according to guiding principles designed to conform practical reason to the ongoing discovery of divine will. This article shows how those principles can function as mechanisms for normative change, and reviews their diagnostic capacity for evaluating various uses of Islamic resources.
Western Buddhist Motivations for Vegetarianism
Authors: Kaza Stephanie
Published: November 2005

Buddhist motivations for abstaining from meat-eating draw from a wide range of traditions. Theravada themes emphasize non-harming, Right Livelihood, and detachment; Mahayana themes highlight interdependence, Buddha-nature, and compassion; Tibetan themes consider rebirth implications for human-animal relationships. These and other contemporary themes overlap with traditional western arguments promoting vegetarianism based on animal welfare, personal and environmental health, world hunger, and ethical development. This paper surveys these themes, then discusses two studies based on survey data that indicate that western Buddhists and Buddhist centers have a wide variety of practices regarding meat-eating. The first survey reports on institutional food choice practices at western Buddhist centers. The second study reports on individual food practices among western Buddhists, with data on food choices and rationales for these choices. In both surveys, Buddhist principles interact with western arguments, leading to diverse decisions about what to eat. As interest in Buddhism grows in the west, Buddhist moral concerns regarding food could influence western food choices in a significant way.
Expropriating Nature: The Decoding of Deep Ecology
Authors: Lauer Dean
Published: November 2005

In this essay, I suggest that Nina Witoszek's semiotic dismantling of Arne Næss' philosophy of deep ecology is more than just an effort to situate Næss within the tradition of his native culture. Her sociological method, perhaps unwittingly, is hostile to the phenomenological possibility of what Næss calls "spontaneous experience". Because the "decoding" of deep ecology takes place in the context of a sign-functional nexus, deep ecology's most valuable asset, the possibility for intimate experience and identification with nature, becomes expropriated within the system of signs. In other words, the cerebral and theoretical force of semiotic analysis may block access to the profound understanding of nature to which Næss' philosophy is dedicated.
Body condition and clutch desertion in penduline tit Remiz pendulinus
Authors: Komdeur Jan , Szentirmai Istvan , Székely Tamas , Bleeker Maarten , Kingma Sjouke A.
Published: November 2005

Parental care is costly since it takes time and energy, and whilst caring the parent may be predated. The benefits of care (i.e., viable offspring) however, are shared equally between the genetic parents: the male and the female. Thus a conflict occurs between the parents over care in many multiple-brooding animals, since each parent prefers the other to do the hard work of raising young ('sexual conflict over care'). One of the most striking examples of this conflict occurs in a small passerine bird, the penduline tit Remiz pendulinus in which both the male and the female may sequentially mate with several mates within a single breeding season. Incubation and brood-rearing are carried out by a single parent (either the male or the female). However, about 30% of clutches are abandoned by both parents. We investigated how body condition may influence parental behaviour of male and female penduline tits. We show that three measures of body condition (body mass, fat reserves and haematocrit value) are consistent with each other for males, although not for females. Nest building appears to be energetically more demanding than incubation in both sexes. In line with this, we found that males and females in good condition deserted their clutch more often than males and females in poor condition. Individuals in poor condition may care because incubation is energetically less expensive than nest building, and they cannot afford the energy requirement of building a new nest. We argue that understanding body condition in the context of parental care is both challenging and essential, since mathematical models (single-parent optimisation models and game-theory models) provide conflicting predictions. Future work, preferably by experimentally manipulating the body condition of penduline tits, is needed to test how body condition influences caring/deserting decisions in this puzzling avian system.
Adoption as a gosling strategy to obtain better parental care? Experimental evidence for gosling choice and age-dependency of adoption in greylag geese
Authors: Komdeur Jan , Kalmbach Ellen , van der Aa Pascal
Published: November 2005

Adoptions of unrelated young by successful breeders are a form of alloparental care which has been observed in many species of geese. Depending on costs and benefits to the parents, adoptions might represent an inter-generational conflict or a mutually beneficial strategy. Although most studies of wild populations suggest benefits of large brood sizes, incidental observations mostly report aggressive behaviour of parents towards lone goslings. No studies have investigated mechanisms and behaviour during adoptions in order to test whether adoptions are driven by parents or goslings. To test whether goslings might use adoption as a strategy to obtain better parental care, we carried out an experiment where lone greylag goose (Anser anser) goslings could choose between a dominant and a subordinate foster family. In a second experiment we also tested whether adoption was age-dependent. Except for one case, all lone goslings (N = 16) chose the dominant family. Parents showed very little aggression towards lone goslings at three days after hatch, but aggression increased until 9 days and remained high thereafter. At the same time as aggression increased, the chance of successful adoption decreased. In the first five weeks of life, goslings which had been adopted were no further away from parents than original goslings during grazing. These results show that goslings might choose foster families according to dominance. The fact that with increasing gosling age parents are less willing to adopt could be due to improved individual recognition and reflect decreasing benefits of gaining an additional family member. More detailed studies on state-dependent costs and benefits of adoptions are required to determine whether adoptions in geese represent conflict or mutualism, and why this changes with gosling age.
Individuality in the contact calls of cooperatively breeding long-tailed tits (Aegithalos caudatus)
Authors: Sharp S.P , Hatchwell B.J.
Published: November 2005

The ability to discriminate between individuals or groups of individuals is important for the evolution of sociality. Individual vocal recognition is thought to be widespread in social birds, yet few studies have investigated its role in cooperatively breeding species. In long-tailed tits, helpers preferentially provide care to close kin, and individuals are able to discriminate between the vocalisations of kin and non-kin. However, the mechanism underlying this recognition system is unknown. Here we quantify the relative variation between and within individuals in three of the contact calls used by this species. Spectrographic cross-correlation revealed that two of these calls, the 'churr' and the 'triple', were individually distinct. We therefore analysed the variation in a series of acoustic parameters in each of these two vocalisations. For both the churr and the triple, discriminant function analysis was able to allocate calls to the correct individuals according to variation in several frequency parameters. We hypothesise that long-tailed tits are able to discriminate between the calls of conspecifics based on these parameters. This is the first quantitative description of potential recognition cues in a cooperatively breeding bird in which vocal discrimination is known to occur.
The study of function in behavioural ecology
Authors: Cuthill Innes
Published: November 2005

In 1963, a landmark paper by Niko Tinbergen laid out the aims and methods of ethology and, in so doing, extended and clarified Julian Huxley's classification of the different ways in which one can investigate biological processes. I discuss the status of one of these "four Why questions", that of function or survival value, and the relationship of Tinbergen's ethology to behavioural ecology, the main field asking functional questions about animal behaviour today. Function itself can be defined in many different ways and behavioural ecologists themselves use it both in the context of current utility and selective history. I review these definitions in the light of analyses by philosophers of science, behavioural ecologists and, of course, Tinbergen's own use of the word. I defend the view, accepted by many philosophers of science, that the definition of 'function' must have a historical component, both to avoid teleology and to retain the everyday sense of questioning 'What is it for?' That said, in reviewing the different methods that can be used to determine function, I defend the view that investigations of current utility, as practised by behavioural ecologists, can provide the most important clues to the selective forces that have shaped behaviours. Finally, I consider the evolution of the discipline of behavioural ecology, its current status and future prospects.