900 research outputs found
Organisational resilience and emergency management
The concept of resilience figures prominently in discussions of disaster risk reduction, emergency management and community safety. Overwhelmingly, such discussions view resilience as a highly desirable characteristic of communities. Policies and practices of emergency services organisations imply that a major role of such organisations is to promote and foster community resilience. Yet there is little appreciation of the importance of resilience as a necessary characteristic of emergency services organisations. In this paper we argue that emergency services organisations need to address their own resilience issues in order to properly fulfil their community protection responsibilities. The concept of organisational resilience in relation to Australia's volunteer-based emergency services organisations is discussed and the importance of organisational climate and organisational culture in relation to organisational resilience is stressed
Semicircular canals circumvent Brownian Motion overload of mechanoreceptor hair cells
<p>Vertebrate semicircular canals (SCC) first appeared in the vertebrates (i.e. ancestral fish) over 600 million years ago. In SCC the principal mechanoreceptors are hair cells, which as </p><p>compared to cochlear hair cells are distinctly longer (70 vs. 7 μm), 10 times more compliant to bending (44 vs. 500 nN/m), and have a 100-fold higher tip displacement threshold (< 10 μm vs. <400 nm).We have developed biomechanical models of vertebrate hair cells where the </p><p>bundle is approximated as a stiff, cylindrical elastic rod subject to friction and thermal agitation. Our models suggest that the above differences aid SCC hair cells in circumventing the masking effects of Brownian motion noise of about 70 nm, and thereby permit transduction of </p><p>very low frequency (<10 Hz) signals.We observe that very low frequency mechanoreception </p><p>requires increased stimulus amplitude, and argue that this is adaptive to circumvent Brownian motion overload at the hair bundles. We suggest that the selective advantage of detecting such low frequency stimuli may have favoured the evolution of large guiding structures such as semicircular canals and otoliths to overcome Brownian Motion noise at the level of the mechanoreceptors of the SCC.</p
De Sitter solutions in N=4 matter coupled supergravity
We investigate the scalar potential of gauged N=4 supergravity with matter.
The extremum in the SU(1,1)/U(1) scalars is obtained for an arbitrary number of
matter multiplets. The constraints on the matter scalars are solved in terms of
an explicit parametrisation of an
SO(6,6+n) element. For the case of six matter multiplets we discuss both
compact and noncompact gauge groups.
In an example involving noncompact groups and four scalars we find a
potential with an absolute minimum and a positive cosmological constant.Comment: 14 page
Aquaculture and its role in integrated coastal zone management: handbook of contributions and extended abstracts presented at the International Workshop on "Aquaculture and its role in Integrated Coastal Zone Management" Oostende, Belgium, April 19-21, 2001
Haalbaarheidsstudie met betrekking tot mariene onderzoeksinfrastructuur in Vlaanderen. Een nieuw Vlaams vaartuig voor kustgebonden marien onderzoek: resultaten van de open bevraging van de mariene onderzoeksgemeenschap
Mutual Information, Strange Attractors, and the Optimal Estimation of Dimension
It has been shown that the appropriate setting of data windows is crucial to a successful estimation of a time-series correlation dimension using the Grassberger-Procaccia algorithm [Physica 9D, 189 (1983); Phys. Rev. Lett. 50, 346 (1983)], and it has been proposed that the first minimum of the corresponding mutual-information function may be an appropriate window value. We have tested this hypothesis against data generated by the Rossler equations, the Lorenz equations, and a three-dimensional irrational torus. We conclude that mutual information is not consistently successful in identifying the optimal window
Longitudinal stability augmentation of seaplanes in planing
The towing tank experiments conducted at Yokohama National University from November 30 to December 9 in 2005 suggested a new way of suppressing a dangerous coupled motion between heave and pitch called porpoising. The research in this paper was developed on the observations made in the experiments and conducted numerical simulations to further investigate the parametric design space. Two linear-time-invariant models were developed: rigid-body planing craft (conventional float planes or flying boats), and flexibly supported planing craft. The latter could simulate the new method found in the experiments for suppressing porpoising. In this study, the stability of the oscillatory motions was analyzed to see the effect of design variables on the inception of porpoising. The parametric study of flexibly supported float planes in the context of porpoising was a new contribution in the conceptual design of seaplanes
Singular-Value Decomposition and the Grassberger-Procaccia Algorithm
A singular-value decomposition leads to a set of statistically independent variables which are used in the Grassberger-Procaccia algorithm to calculate the correlation dimension of an attractor from a scalar time series. This combination alleviates some of the difficulties associated with each technique when used alone, and can significantly reduce the computational cost of estimating correlation dimensions from a time series
Inequality, poverty and the privatization of essential services: A "systems of provision" study of water, energy and local buses in the UK
This paper is concerned with the distributional effects of the deregulation and privatization of essential services in Britain since the 1980s, based on a cross-sector study of water, energy and local bus transport. Our approach locates end users within the structures and processes, and prevailing narratives that underpin both production and consumption. This framework highlights the ways that the provisioning of these vital services is contested, contradictory and underpinned by power relations. We show that, at one end, investors in these sectors have made generous returns on their investments but their methods of profit maximization are often not in the public interest. Meanwhile these profits are financed by end users’ payments of bills and fares. Many lower-income households face challenges in terms of affording, and even accessing, these essential services. Regulation has failed to provide adequate social protection. We argue that adverse social outcomes emerge from systemic factors embedded in these modes of provision. A narrative of politically-neutral, technocratic solutions belies the underlying contested nature of privatized monopolistic shared essential services. Moreover, a policy preoccupation with markets and competition obscures the inequality embedded in the underlying structures and processes and undermines more collective and equitable forms of provisioning
- …