On the problem of algebraic completeness for the invariants of the Riemann tensor. II

We study the set of invariants CZ [E. Zakhary and J. Carminati, J. Math. Phys. 42, 1474 (2001)] for the class of space-times whose Ricci tensors do not possess a null eigenvector. We show that all cases are completely backsolvable in terms of sets of invariants from CZ. We provide algebraically complete sets for each canonically different space-time.

Green bodies : training environmental educators

In this paper, we examine the “greening” of Outdoor & Environmental Education (OEE) students at an Australian regional university through three lenses: temporal, spatial & material. We are inspired by Grosz’ claim that “bodies are always understood within a spatial & temporal context, & space & time remain conceivable only insofar as corporeality provides the basis for our perception & representation of them” (1995, p. 84). As suggested by Grosz, these lenses are not discrete and, in the course of the paper, their intersections & reciprocity become apparent. We draw on interview responses & observations from a longitudinal cohort study undertaken by Preston in an attempt to trace the regulation and practice of “green” “outdoor Ed” subjectivities in the context of the materialities, time & spaces of this specific course. Grosz, E.A. (1995) Space, Time & Perversion: The Politics of Bodies, New York: Routledge

Human action recognition based on 3D SIFT and LDA model

How to recognize human action from videos captured by modern cameras efficiently and effectively is a challenge in real applications. Traditional methods which need professional analysts are facing a bottleneck because of their shortcomings. To cope with the disadvantage, methods based on computer vision techniques, without or with only a few human interventions, have been proposed to analyse human actions in videos automatically. This paper provides a method combining the three dimensional Scale Invariant Feature Transform (SIFT) detector and the Latent Dirichlet Allocation (LDA) model for human motion analysis. To represent videos effectively and robustly, we extract the 3D SIFT descriptor around each interest point, which is sampled densely from 3D Space-time video volumes. After obtaining the representation of each video frame, the LDA model is adopted to discover the underlying structure-the categorization of human actions in the collection of videos. Public available standard datasets are used to test our method. The concluding part discusses the research challenges and future directions.

Thought and feeling in Giedion's mechanization takes command

An internal crisis within architecture and the way historiography both presents and conceals it, can be seen most strikingly in the contrast between two publications by the architectural historian Sigfried Giedion, Space Time and Architecture: The Growth of a New Tradition, published in 1941, and Mechanization Takes Command: A Contribution to Anonymous History, published in 1948. These two publications take us back to the scene of World War Two, the former during the war and after Giedion's affair with America, and the latter after the war. At the time of publication Giedion's former book, Space, Time and Architecture, was seen as a "blockbuster" by the architectural community (especially in the USA). The latter publication, Mechanization, did not receive a favourable response by the same professional community. Their contrasting historiography suggests that the internal crisis of architecture is in a constant struggle with architecture's exterior, in this case, war. Giedion's Mechanization can be seen as the shadow text of the progressive myth of the former. With a focus on Mechanization, the paper aims to open its discursive approach to history. The post-war city is where Giedion's publications and my studies on "a gap of history" coincide and intersect. Giedion is fascinated with psychic factors shown in the recurring theme of the split between thought and feeling and exemplified in the dialectic between image and text. Drawing on psychoanalytic theory I argue that this functions as a mirror-stage in relation to a discourse on architecture and to architecture's disciplinary boundaries where the subject of architecture lacks the ideality and unity that is represented in the former publication.

Predicting avian distributions to evaluate spatiotemporal overlap with locust control operations in eastern Australia.

Locusts and grasshoppers cause considerable economic damage to agriculture worldwide. The Australian Plague Locust Commission uses multiple pesticides to control locusts in eastern Australia. Avian exposure to agricultural pesticides is of conservation concern, especially in the case of rare and threatened species. The aim of this study was to evaluate the probability of pesticide exposure of native avian species during operational locust control based on knowledge of species occurrence in areas and times of application. Using presence-absence data provided by the Birds Australia Atlas for 1998 to 2002, we developed a series of generalized linear models to predict avian occurrences on a monthly basis in 0.5 degrees grid cells for 280 species over 2 million km2 in eastern Australia. We constructed species-specific models relating occupancy patterns to survey date and location, rainfall, and derived habitat preference. Model complexity depended on the number of observations available. Model output was the probability of occurrence for each species at times and locations of past locust control operations within the 5-year study period. Given the high spatiotemporal variability of locust control events, the variability in predicted bird species presence was high, with 108 of the total 280 species being included at least once in the top 20 predicted species for individual space-time events. The models were evaluated using field surveys collected between 2000 and 2005, at sites with and without locust outbreaks. Model strength varied among species. Some species were under- or over-predicted as times and locations of interest typically did not correspond to those in the prediction data set and certain species were likely attracted to locusts as a food source. Field surveys demonstrated the utility of the spatially explicit species lists derived from the models but also identified the presence of a number of previously unanticipated species. These results also emphasize the need for special consideration of rare and threatened species that are poorly predicted by presence-absence models. This modeling exercise was a useful a priori approach in species risk assessments to identify species present at times and locations of locust control applications, and to discover gaps in our knowledge and need for further focused data collection.

The in‐between: exposing everyday learning at work

Much has been written about how space and time are integral to understanding social relations, in particular about associations between space and understanding learning in workplaces. Drawing from a research study exploring everyday learning at work, this paper looks beyond what is generally understood as work situations by turning to those spaces and times where ‘social’ and ‘work’ overlap, such as breaks in tearooms. These spaces are not so work orientated that they can be described as ‘workspaces’, nor are they entirely social. The nexus between work and the social, of being a worker and a social being, of engaging in legitimate work and socializing are put forward as rich expanses for everyday learning. The paper draws on interviews and observational data from four work sites within one organization. It undertakes an exploration of the intersection of space, time and informal learning with regard to the social/work spaces located at work. It argues that a key location for everyday learning at work is at the points of intersection between work and social spaces and that it is necessary to abandon simplistic dichotomies between work, social and learning space.

Being, vitruvian

"Being, Vitruvian" is the first of two exhibitions encompassing the visual narrative of Daniela Bertol’s creative research "Form Mind Body Space Time" where practices of "making" intersect practices of "moving". ‘Making movement’ is inspired by geometric configurations which are also archetypical shapes and symbols in several cultures and are deeply embedded in the human psyche.

Riding parallel

This extended poem deploys a mode of ekphrasis to perform queer desire as metonymically proliferative, from the sublime to the abject, but always productive. At the same time, it celebrates this propensity as a mode of positive haunting which multiplies experience through improbable connections across space-time.

Globalizing time and space : temporal and spatial considerations in discourses of globalization

Globalization discourse is concerned with the effects of spatial change—changes in the shape, scale and extensity or social processes— and the effects of temporal change—particularly changes to, or away from, modernity. By drawing together both axes of change, globalization discourse suggests a way of navigating this tension. However, it is argued here that most globalization theories accord primacy to one of these axes, which results in them being conflated. As a result, globalization theories are often presented in highly systemic terms and downplay the diversity of social processes.

Australian waterbirds : time and space travellers in dynamic desert landscapes

Australia’s waterbirds are mostly nomadic, capitalising on highly variable aquatic resources in the arid interior (70% of the continent) for feeding and breeding. Waterbirds, unlike most aquatic organisms, can move between catchments, exploiting habitat wherever it occurs. In Australia, patterns of resource availability for waterbirds are mostly pulsed with peaks of productivity, coinciding with flooding and differing in time and space, affecting individuals, species and functional groups of waterbirds. Australian waterbirds are no different from waterbirds elsewhere, with their behaviour reflecting broad-scale resource availability. They respond to changing patterns of resource distribution, with rapid movements at spatial and temporal scales commensurate with the dynamics of the resource. The most serious conservation threat to waterbirds is a bottleneck in resource availability, leading to population declines, increasingly forced by anthropogenic impacts. River regulation and other threats (e.g. draining) reduce the availability of wetland habitat and decrease the probability of viable resource patches. It is axiomatic that waterbirds need water and such population bottlenecks may occur when the availability of water across the continent is limited. The rehabilitation of regulated rivers with environmental flows and protection of naturally flowing rivers in the arid region are essential for long-term sustainability of Australia’s waterbird populations.

Space-for-time substitution to assess likely response of aquatic ecosystems to future climate-related change

Predicting and managing ecological response to a changing climate is often limited by an incomplete understanding of response thresholds and biogeographic differences. For example, step changes in rainfall and runoff, and threshold dynamics and hysteresis in ecological response make projection of future conditions difficult. To combat these constraints we propose that biophysical data across exiting climatic gradients can be used in a space-for-time substitution to predict climate-related ecological response elsewhere. This method builds on previous attempts at space-for-time substitution by using patterns in physical and physicochemical data to explain biological differences across the spatial gradient, then using those patterns to formulate hypotheses of temporal ecological response and finally testing those hypotheses on temporal data available in a second, similar region of interest.