Do dogs (canis familiaris) understand invisible displacement?

Domestic dogs (Canis familiaris) perform above chance on invisible displacement tasks despite showing few other signs of possessing the necessary representational abilities. Four experiments investigated how dogs find an object that has been hidden in 1 of 3 opaque boxes. Dogs passed the task under a variety of control conditions, but only if the device used to displace the object ended up adjacent to the target box after the displacement. These results suggest that the search behavior of dogs was guided by simple associative rules rather than mental representation of the object's past trajectory. In contrast, Experiment 5 found that on the same task, 18- and 24-month-old children showed no disparity between trials in which the displacement device was adjacent or nonadjacent to the target box.

Do chimpanzees (Pan troglodytes) understand single invisible displacement?

Previous research suggests that chimpanzees understand single invisible displacement. However, this Piagetian task may be solvable through the use of simple search strategies rather than through mentally representing the past trajectory of an object. Four control conditions were thus administered to two chimpanzees in order to separate associative search strategies from performance based on mental representation. Strategies involving experimenter cue-use, search at the last or first box visited by the displacement device, and search at boxes adjacent to the displacement device were systematically controlled for. Chimpanzees showed no indications of utilizing these simple strategies, suggesting that their capacity to mentally represent single invisible displacements is comparable to that of 18-24-month-old children.

Do chimpanzees (Pan troglodytes) and 2-year-old children (Homo sapiens) understand double invisible displacement?

Chimpanzees (Pan troglodytes) and young children (Homo sapiens) have difficulty with double invisible displacements in which an object is hidden in two nonadjacent boxes in a linear array. Experiment 1 eliminated the possibility that chimpanzees' previous poor performance was due to the hiding direction of the displacement device. As in Call (2001), subjects failed double nonadjacent displacements, showing a tendency to select adjacent boxes. In Experiments 2 and 3, chimpanzees and 24-month-old children were tested on a new adaptation of the task in which four hiding boxes were presented in a diamond-shaped array on a vertical plane. Both species performed above chance on double invisible displacements using this format, suggesting that previous poor performance was due to a response bias or inhibition problem rather than a fundamental limitation in representational capacity.

Contributions of vision-proprioception interactions to the estimation of time-varying hand and target locations

We investigated the relative importance of vision and proprioception in estimating target and hand locations in a dynamic environment. Subjects performed a position estimation task in which a target moved horizontally on a screen at a constant velocity and then disappeared. They were asked to estimate the position of the invisible target under two conditions: passively observing and manually tracking. The tracking trials included three visual conditions with a cursor representing the hand position: always visible, disappearing simultaneously with target disappearance, and always invisible. The target’s invisible displacement was systematically underestimated during passive observation. In active conditions, tracking with the visible cursor significantly decreased the extent of underestimation. Tracking of the invisible target became much more accurate under this condition and was not affected by cursor disappearance. In a second experiment, subjects were asked to judge the position of their unseen hand instead of the target during tracking movements. Invisible hand displacements were also underestimated when compared with the actual displacement. Continuous or brief presentation of the cursor reduced the extent of underestimation. These results suggest that vision–proprioception interactions are critical for representing exact target–hand spatial relationships, and that such sensorimotor representation of hand kinematics serves a cognitive function in predicting target position. We propose a hypothesis that the central nervous system can utilize information derived from proprioception and/or efference copy for sensorimotor prediction of dynamic target and hand positions, but that effective use of this information for conscious estimation requires that it be presented in a form that corresponds to that used for the estimations.

Biomechanical force displacement analysis of strength of fixation of tracker holding devices to bone in computer aided joint replacement

Computer aided joint replacement surgery has become very popular during recent years and is being done in increasing numbers all over the world. The accuracy of the system depends to a major extent, on accurate registration and immobility of the tracker attachment devices to the bone. This study was designed to asses the forces needed to displace the tracker attachment devices in the bone simulators. Bone simulators were used to maintain the uniformity of the bone structure during the study. The fixation devices tested were 3mm diameter self drilling, self tapping threaded pin, 4mm diameter self tapping cortical threaded pin, 5mm diameter self tapping cancellous threaded pin and a triplanar fixation device ‘ortholock’ used with three 3mm pins. All the devices were tested for pull out, translational and rotational forces in unicortical and bicortical fixation modes. Also tested was the normal bang strength and forces generated by leaning on the devices. The forces required to produce translation increased with the increasing diameter of the pins. These were 105N, 185N, and 225N for the unicortical fixations and 130N, 200N, 225N for the bicortical fixations for 3mm, 4mm and 5mm diameter pins respectively. The forces required to pull out the pins were 1475N, 1650N, 2050N for the unicortical, 1020N, 3044N and 3042N for the bicortical fixated 3mm, 4mm and 5mm diameter pins. The ortholock translational and pull out strength was tested to 900N and 920N respectively and still it did not fail. Rotatory forces required to displace the tracker on pins was to the magnitude of 30N before failure. The ortholock device had rotational forces applied up to 135N and still did not fail. The manual leaning forces and the sudden bang forces generated were of the magnitude of 210N and 150N respectively. The strength of the fixation pins increases with increasing diameter from three to five mm for the translational forces. There is no significant difference in pull out forces of four mm and five mm diameter pins though it is more that the three mm diameter pins. This is because of the failure of material at that stage rather than the fixation device. The rotatory forces required to displace the tracker are very small and much less that that can be produced by the surgeon or assistants in single pins. Although the ortholock device was tested to 135N in rotation without failing, one has to be very careful not to put any forces during the operation on the tracker devices to ensure the accuracy of the procedure.

Contemporary dramaturgy in theatre for young people : the conceptual shape of displacement and installation

This thesis investigates Theatre for Young People (TYP) as a site of performance innovation. The inquiry is focused on contemporary dramaturgy and its fieldwork aims to identify new dramaturgical principles operating in the creation and presentation of TYP. The research then seeks to assess how these new principles contribute to Postdramatic Theatre theory. This research inquiry springs from an imperative based in practice: Young people under 25 years have a literacy based on online hypertextual experiences which take the reader outside the frames of a dramatic narrative and beyond principles such as linearity, dramatic unity, teleology and resolution. As a dramaturg and educator I wanted to understand the new ways that young people engage in cultural products, to identify and utilize the new principles of dramaturgy that are now in evidence. My research examines how two playwright/directors approach their work and the new principles that can be identified in their dramaturgy. The fieldwork is scoped into two case studies: the first on TJ Eckleberg working in Australian Theatre for Young People and the second on Kristo Šagor working in German Children’s and Young People’s Theatre (KJT). These case studies address both types of production dramaturgy - the dramaturgy emergent through process in devised performance making, and that emergent in a performance based on a written playscript. On Case Study One the researcher, as participant observer, worked as production dramaturg on a large scale, site specific performance, observing the dramaturgy in process of its director and chief devisor. On Case Study Two the researcher, as observer and analyst, undertook a performance analysis of three playscripts and productions by a contemporary German playwright and director. Utilizing participant observation, reflective practice and grounded analysis the case studies have identified two new principles animating the dramaturgy of these TYP practitioners, namely ‘displacement’ and ‘installation.’ Taking practice into theory, the thesis concludes by demonstrating how displacement and installation contribute to Postdramatic Theatre’s “arsenal of expressive gestures which serve as theatre’s response to changed social communication under the conditions of generalized communication technologies” (Lehmann, H.-T., 2006, p.23). This research makes an original contribution to knowledge by evidencing that the principles of Postdramatic Theory lie within the practice of contemporary Theatre for Young People. It also contributes valuable research to a specialized, often overlooked terrain, namely Dramaturgy in Theatre for Young People, presented here with a contemporary, international and intercultural perspective.

Rapid displacement of dengue virus type 1 by type 4, Pacific region, 2007-2009

Since 2000-2001, dengue virus type 1 has circulated in the Pacific region. However, in 2007, type 4 reemerged and has almost completely displaced the strains of type 1. If only 1 serotype circulates at any time and is replaced approximately every 5 years, DENV-3 may reappear in 2012.

Anion induced displacement studies in naphthalene diimide containing interpenetrated and interlocked structures

This article describes investigations into the development of supramolecular systems capable of sensing anions through either displacement type assays or molecular motion. An electron deficient naphthalene diimide thread and electron rich isophthalamide naphthohydroquinone macrocycle was shown to form a coloured pseudorotaxane assembly. Investigations into the ability of such interpenetrated systems to sense anions colorimetrically were undertaken. Anion complexation to the isophthalamide group of the macrocycle causes displacement of the naphthodiimide thread resulting in the loss of colour. The enhanced mechanically bonded binding strength between the naphthodiimide axle and the naphthohydroquinone groups of the macrocycle wheel in the corresponding rotaxane structure however, was found to negate the anion induced displacement process.

Using Fiber Bragg Grating (FBG) sensors for vertical displacement measurement of bridges

In many bridges, vertical displacements are one of the most relevant parameters for structural health monitoring in both the short and long terms. Bridge managers around the globe are always looking for a simple way to measure vertical displacements of bridges. However, it is difficult to carry out such measurements. On the other hand, in recent years, with the advancement of fiber-optic technologies, fiber Bragg grating (FBG) sensors are more commonly used in structural health monitoring due to their outstanding advantages including multiplexing capability, immunity of electromagnetic interference as well as high resolution and accuracy. For these reasons, using FBG sensors is proposed to develop a simple, inexpensive and practical method to measure vertical displacements of bridges. A curvature approach for vertical displacement measurement using curvature measurements is proposed. In addition, with the successful development of a FBG tilt sensors, an inclination approach is also proposed using inclination measurements. A series of simulation tests of a full-scale bridge was conducted. It shows that both the approaches can be implemented to determine vertical displacements for bridges with various support conditions, varying stiffness (EI) along the spans and without any prior known loading. These approaches can thus measure vertical displacements for most of slab-on-girder and box-girder bridges. Moreover, with the advantages of FBG sensors, they can be implemented to monitor bridge behavior remotely and in real time. Further recommendations of these approaches for developments will also be discussed at the end of the paper.

Frantic fashion and Australia’s invisible designers : conversations on sustainability in the mass market

The majority of Australians will work, sleep and die in the garments of the mass market. Yet, as Ian Griffiths has termed it, the designers of these garments are ‘invisible’ (2000). To the general public, the values, opinions and individual design processes of these designers are as unknown as their names. However, the designer’s role is crucial in making decisions which will have impacts throughout the life of the garment. The high product volume within the mass market ensures that even a small decision in the design process to source a particular fabric, or to use a certain trim or textile finish, can have a profound environmental or social effect. While big companies in Australia have implemented some visible strategies for sustainability, it is uncertain how these may have flowed through to design practices. To explore this question, this presentation will discuss preliminary findings from in-depth semi-structured interviews with Australian mass market fashion designers and product developers. The aim of the interviews was to hear the voice of the insider – to listen to mass market designers describe their design process, discuss the Australian fashion industry and its future challenges and opportunities, and to comment on what a ‘sustainability’ for their industry could look like. These interviews will be discussed within the framework of design philosopher Tony Fry’s writing on design redirection for sustainability.

Visualising invisible networks as collaborative arts practice

This paper examines approaches to the visualisation of ‘invisible’ communications networks. It situates network visualisation as a critical design exercise, and explores how community artists might use such a practice to develop telematic art projects – works that use communications networks as their medium. The paper’s hypotheses are grounded in the Australian community media arts field, but could be applied to other collaborative contexts.