Are shadows only coarsely processed? Exploring depth discrimination with cast shadow cue conflicts across spatial frequency

Shape-from-shading is a ubiquitous cue informing object identification and depth judgements. Cast-shadows contribute towards these judgements (see Mammassian, Knill and Kersten, 1998). A number of studies have reported that search-times for inconsistent shadows vary according to whether the scene is presented as-if illuminated from above or below. Though the direction of these inhomogeneities is sometimes contested (see Rensink and Cavanagh, 2004 and Lovell et al, 2009). Lovell et. al. posit that the processing of shadows is handled by coarse-scale processes, but only in light-from-above presentations. The current study explores depth discrimination judgements informed by cast shadows. We create stimuli featuring a pair of floating discs, casting shadows onto a fronto-parallel surface. Participants were asked to identify the disc protruding the most towards them. One disc featured a cast-shadow with a cue-conflict, where low and high spatial-frequency components conveyed different depth information. This allowed us to estimate the weight assigned to the different cues when depth discrimination judgements were made. Firstly, we find that depth judgements consistently reflected the coarse-scale cues, fine-scale cues were largely ignored. Secondly, we found only small differences in the cue weightings for stimuli presented as-if light were above or below. The latter result is perplexing as previous studies have shown a difference between light-from-above and below conditions. We speculate that this difference reflects the task undertaken, i.e. discriminating depths rather than searching for odd shadows

Ecstasy: 3,4-Methylenedioxymethamphetamine (MDMA)

This is the published version. Copyright 1998 International Union of CrystallographyThe crystal structure of 3,4-methylenedioxymethamphetamine {systematic name: N-methyl-l-[3,4-(methylenedioxy) phenyl]-2-aminopropane } hydrochloride, C 11H 15 - NO2.HC1, also known as 'ecstasy' or MDMA, has been determined by X-ray diffraction

Round table on camouflage

Research into camouflage has exploded over the last decade or so, with interdisciplinarity proving to be a key feature for progress. In our round table, we will address three main questions: (i) why are we researching camouflage; (ii) how do we research camouflage; and (iii) what is camouflage, and how do we measure it? These are really just starting points for what we hope will be an informative, interactive and wide-ranging discussion. Gibson Revisited: toward understanding sensory affordances of real-world environments Ute Leonards, School of Psychological Science, University of Bristol More than 50 years ago, JJ Gibson introduced the concept of affordances, which directly link actions to available information in our environments. Yet, even today, there is little crosstalk between visual cognition research and locomotion research, preventing us from understanding the affordances of sensory environments in real-world environments. In my talk, I will outline how following a Gibsonian approach could help us to find solutions to pressing societal issues such as understanding how the environments we create impact our health and wellbeing or how we could reduce fall risk in an ageing population. In a series of experiments, I will provide evidence of how the visual environment affects gait, even in hazard-free environments during walking on even ground—be it through the patterns on floor coverings or, more generally, the type of visual environment we are in. I will finish my talk with an outlook that goes beyond the research laboratory to modern urban design and will present a first attempt at a theoretical framework of Sustainable Urban Design informed by vision sciences

Institutional memory: we need a more dynamic understanding of the way institutions remember

Institutional memory is central to the task of governing. But existing understandings of how institutional memory works are too limiting and rooted in an ontological falsehood, argue Jack Corbett, Dennis C. Grube, Heather Lovell, and Rodney Scott. They explain why a more dynamic approach is needed

Singular memory or institutional memories? Toward a dynamic approach

The ability of the civil service to act as a reservoir of institutional memory is central to the pragmatic task of governing. But there is a growing body of scholarship that suggests the bureaucracy is failing at this core task. In this article, we distinguish between two different ways of thinking about institutional memory: one “static” and one “dynamic.” In the former, memory is singular and held in document form, especially by files and procedures. In the latter, memories reside with people and are thus dispersed across the array of actors that make up the differentiated polity. Drawing on four policy examples from three countries, we argue that a more dynamic understanding of the way institutions remember is both empirically salient and normatively desirable. We conclude that the current conceptualization of institutional memory needs to be recalibrated to fit the types of policy learning practices required by modern collaborative governance.... thanks are due to the Australia and New Zealand School of Government for the grant that funded the research, and to the Institute for the Study of Social Change at the University of Tasmania for its support. Some initial research assistance was provided by Thomas Butler. Heather Lovell would also like to thank the Australian Research Council, which part funded the Victorian Smart Meter case under its Future Fellowships program—Project ID FT140100646

An osmium nitrido complex as a π-acid ligand for late transition metals

This is the published version. Copyright Royal Society of ChemistryThe Os(VI) nitrido complex, TpOs(N)Cl2 (1), acts as a π-acid ligand in the cobalt and platinum complexes CpCo[NOs(Tp)Cl2]2 (2) and (Me2S)Cl2Pt–N[triple bond, length half m-dash]Os(Tp)Cl2 (3)

Mechanism of the asymmetric activation of the MinD ATPase by MinE

This is the peer reviewed version of the following article: Park, K.-T., Wu, W., Lovell, S. and Lutkenhaus, J. (2012), Mechanism of the asymmetric activation of the MinD ATPase by MinE. Molecular Microbiology, 85: 271–281. doi:10.1111/j.1365-2958.2012.08110.x, which has been published in final form at http://doi.org/10.1111/j.1365-2958.2012.08110.x. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.MinD is a component of the Min system involved in the spatial regulation of cell division. It is an ATPase in the MinD/ParA/Mrp deviant Walker A motif family which is within the P loop GTPase superfamily. Its ATPase activity is stimulated by MinE, however, the mechanism of this activation is unclear. MinD forms a symmetric dimer with two binding sites for MinE, however, a recent model suggested that MinE occupying one site was sufficient for ATP hydrolysis. By generating heterodimers with one binding site for MinE we show that one binding site is sufficient for stimulation of the MinD ATPase. Furthermore, comparison of structures of MinD and related proteins led us to examine the role of N45 in the switch I region. An asparagine at this position is conserved in four of the deviant Walker A motif subfamilies (MinD, chromosomal ParAs, Get3 and FleN) and we find that N45 in MinD is essential for MinE stimulated ATPase activity and suggest that it is a key residue affected by MinE binding

Chlamydia trachomatis CT771 (nudH) is an asymmetric Ap4A hydrolase

Asymmetric diadenosine 5′,5′″-P1,P4-tetraphosphate (Ap4A) hydrolases are members of the Nudix superfamily that asymmetrically cleave the metabolite Ap4A into ATP and AMP while facilitating homeostasis. The obligate intracellular mammalian pathogen Chlamydia trachomatis possesses a single Nudix family protein, CT771. As pathogens that rely on a host for replication and dissemination typically have one or zero Nudix family proteins, this suggests that CT771 could be critical for chlamydial biology and pathogenesis. We identified orthologs to CT771 within environmental Chlamydiales that share active site residues suggesting a common function. Crystal structures of both apo- and ligand-bound CT771 were determined to 2.6 Å and 1.9 Å resolution, respectively. The structure of CT771 shows a αβα-sandwich motif with many conserved elements lining the putative Nudix active site. Numerous aspects of the ligand-bound CT771 structure mirror those observed in the ligand-bound structure of the Ap4A hydrolase from Caenorhabditis elegans. These structures represent only the second Ap4A hydrolase enzyme member determined from eubacteria and suggest that mammalian and bacterial Ap4A hydrolases might be more similar than previously thought. The aforementioned structural similarities, in tandem with molecular docking, guided the enzymatic characterization of CT771. Together, these studies provide the molecular details for substrate binding and specificity, supporting the analysis that CT771 is an Ap4A hydrolase (nudH)

Actual Versus Hypothetical WTA Stated Values for Recreational Fishing Licenses: Experimental Evidence of Fish Tales

We compared hypothetical willingness to accept (WTA) values for Massachusetts saltwater recreational fishing licenses with WTA values obtained in an actual (simulated) marketplace. Using a dichotomous choice contingent valuation approach, our results align with past evidence that found WTA values elicited from hypothetical transactions overstate those derived from an actual marketplace. We also provide the first evidence about the effectiveness of an ex-post certainty adjustment technique in a WTA environment. While the adjustment technique has been found to eliminate hypothetical bias in willingness to pay (WTP) settings, we find that when applied in a WTA setting, the approach mitigates but does not eliminate the overstated hypothetical WTA bias. We provide some theoretical conjecture as to the likely reasons why the certainty adjustment approach failed to remove the hypothetical WTA bias in our study and conclude with some practical policy implications