2,303 research outputs found
The visualisation on Pangolin scales using gelatine lifters
Recent media reports document the plight of the Pangolin and its current position as âthe most trafficked mammal in the worldâ. They are described by some as scaly anteaters as all species are covered in hard keratinous tissue in the form of overlapping scales acting as a âflexible dermal armourâ. It is estimated that between 2011 and 2013, 117,000 to 234,000 pangolins were slaughtered, but the seizures may only represent as little as 10% of the true volume of pangolins being illegally traded. In this paper, methods to visualise fingermarks on Pangolin scales using gelatine lifters is presented. The gelatine lifters provide an easy to use, inexpensive but effective method to help wildlife crime rangers across Africa and Asia to disrupt the trafficking. The gelatine lifting process visualised marks producing clear ridge detail on 52% of the Pangolin scales examined, with a further 30% showing the impression of a finger with limited ridge detail. The paper builds on an initial sociotechnical approach to establishing requirement, then it focuses on the methods and outcomes lifting
fingermarks off Pangolin scales using gelatine lifters, providing an evaluation of the viability of using the lifters in practice
The field theory of symmetrical layered electrolytic systems and the thermal Casimir effect
We present a general extension of a field-theoretic approach developed in
earlier papers to the calculation of the free energy of symmetrically layered
electrolytic systems which is based on the Sine-Gordon field theory for the
Coulomb gas. The method is to construct the partition function in terms of the
Feynman evolution kernel in the Euclidean time variable associated with the
coordinate normal to the surfaces defining the layered structure. The theory is
applicable to cylindrical systems and its development is motivated by the
possibility that a static van der Waals or thermal Casimir force could provide
an attractive force stabilising a dielectric tube formed from a lipid bilayer,
an example of which are t-tubules occurring in certain muscle cells. In this
context, we apply the theory to the calculation of the thermal Casimir effect
for a dielectric tube of radius and thickness formed from such a
membrane in water. In a grand canonical approach we find that the leading
contribution to the Casimir energy behaves like which gives
rise to an attractive force which tends to contract the tube radius. We find
that for the case of typical lipid membrane t-tubules. We
conclude that except in the case of a very soft membrane this force is
insufficient to stabilise such tubes against the bending stress which tend to
increase the radius. We briefly discuss the role of lipid membrane reservoir
implicit in the approach and whether its nature in biological systems may
possibly lead to a stabilising mechanism for such lipid tubes.Comment: 28 pages, 2 figures, LaTe
Theory of Cylindrical Tubules and Helical Ribbons of Chiral Lipid Membranes
We present a general theory for the equilibrium structure of cylindrical
tubules and helical ribbons of chiral lipid membranes. This theory is based on
a continuum elastic free energy that permits variations in the direction of
molecular tilt and in the curvature of the membrane. The theory shows that the
formation of tubules and helical ribbons is driven by the chirality of the
membrane. Tubules have a first-order transition from a uniform state to a
helically modulated state, with periodic stripes in the tilt direction and
ripples in the curvature. Helical ribbons can be stable structures, or they can
be unstable intermediate states in the formation of tubules.Comment: 43 pages, including 12 postscript figures, uses REVTeX 3.0 and
epsf.st
Leibniz, Acosmism, and Incompossibility
Leibniz claims that God acts in the best possible way, and that this includes creating exactly one world. But worlds are aggregates, and aggregates have a low degree of reality or metaphysical perfection, perhaps none at all. This is Leibnizâs tendency toward acosmism, or the view that there this no such thing as creation-as-a-whole. Many interpreters reconcile Leibnizâs acosmist tendency with the high value of worlds by proposing that God sums the value of each substance created, so that the best world is just the world with the most substances. I call this way of determining the value of a world the Additive Theory of Value (ATV), and argue that it leads to the current and insoluble form of the problem of incompossibility. To avoid the problem, I read âpossible worldsâ in âGod chooses the best of all possible worldsâ as referring to Godâs ideas of worlds. These ideas, though built up from essences, are themselves unities and so well suited to be the value bearers that Leibnizâs theodicy requires. They have their own value, thanks to their unity, and that unity is not preserved when more essences are added
'You were quiet - I did all the marching': Research processes involved in hearing the voices of South Asian girls
This article is available open access through the publisherâs website at the link below. Copyright @ 2011
A B
Academic
Publishers.This article provides insights into the outcomes of reflection following two interview approaches used to explore narratives of the lived, individual experiences of South-Asian girls living in West London. In attempting to illuminate and re-present the cultural experiences as told by these girls, the choice of interview approach became critical in allowing the voices to be effectively heard (Rogers, 2005). This article therefore considers how a semi-structured interview approach offered valuable insights into the girls' experiences but became constraining for both researcher and participant in unveiling the complexity and depth of their lives. These constraints emerged through reflection by both participants and researcher. As a result of reflexivity during the research process, the researcher moved towards the use of research conversations during the second phase of the study. Ultimately the study revealed how the girls felt empowered by the opportunity to narrate their individual experiences and tell of their lives. In narrating their reflections on being part of the research, there was a clear recognition that the process facilitated the articulation of new voices and âmulti-voicednessâ (Moen, 2006
Supersonic turbulence and structure of interstellar molecular clouds
The interstellar medium (ISM) provides a unique laboratory for highly
supersonic, driven hydrodynamics turbulence. We present a theory of such
turbulence, confirm it by numerical simulations, and use the results to explain
observational properties of interstellar molecular clouds, the regions where
stars are born.Comment: 5 pages, 3 figures include
Multifractal Scaling, Geometrical Diversity, and Hierarchical Structure in the Cool Interstellar Medium
Multifractal scaling (MFS) refers to structures that can be described as a
collection of interwoven fractal subsets which exhibit power-law spatial
scaling behavior with a range of scaling exponents (concentration, or
singularity, strengths) and dimensions. The existence of MFS implies an
underlying multiplicative (or hierarchical, or cascade) process. Panoramic
column density images of several nearby star- forming cloud complexes,
constructed from IRAS data and justified in an appendix, are shown to exhibit
such multifractal scaling, which we interpret as indirect but quantitative
evidence for nested hierarchical structure. The relation between the dimensions
of the subsets and their concentration strengths (the "multifractal spectrum'')
appears to satisfactorily order the observed regions in terms of the mixture of
geometries present: strong point-like concentrations, line- like filaments or
fronts, and space-filling diffuse structures. This multifractal spectrum is a
global property of the regions studied, and does not rely on any operational
definition of "clouds.'' The range of forms of the multifractal spectrum among
the regions studied implies that the column density structures do not form a
universality class, in contrast to indications for velocity and passive scalar
fields in incompressible turbulence, providing another indication that the
physics of highly compressible interstellar gas dynamics differs fundamentally
from incompressible turbulence. (Abstract truncated)Comment: 27 pages, (LaTeX), 13 figures, 1 table, submitted to Astrophysical
Journa
Three-body correlations in Borromean halo nuclei
Three-body correlations in the dissociation of two-neutron halo nuclei are
explored using a technique based on intensity interferometry and Dalitz plots.
This provides for the combined treatment of both the n-n and core-n
interactions in the exit channel. As an example, the breakup of 14Be into
12Be+n+n by Pb and C targets has been analysed and the halo n-n separation
extracted. A finite delay between the emission of the neutrons in the reaction
on the C target was observed and is attributed to 13Be resonances populated in
sequential breakup.Comment: 5 pages, 4 figures, submitted to PR
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