3,824 research outputs found
Tumor stiffness extends its grip on the metastatic microenvironment
The increased stiffness of a tumor triggers a multitude of responses that aid cancer cell dissemination. Stiffness-induced expression of CCN1 mediates autocrine signaling in the endothelium to upregulate N-Cadherin levels. This permits more stable interactions with cancer cells and increases their ability to spread into the circulation
Efficient Computation of Power, Force, and Torque in BEM Scattering Calculations
We present concise, computationally efficient formulas for several quantities
of interest -- including absorbed and scattered power, optical force (radiation
pressure), and torque -- in scattering calculations performed using the
boundary-element method (BEM) [also known as the method of moments (MOM)]. Our
formulas compute the quantities of interest \textit{directly} from the BEM
surface currents with no need ever to compute the scattered electromagnetic
fields. We derive our new formulas and demonstrate their effectiveness by
computing power, force, and torque in a number of example geometries. Free,
open-source software implementations of our formulas are available for download
online
Modeling effects of nonbreeders on population growth estimates
Acknowledgements We thank the Beissinger lab and reviewers for helpful comments on manuscript drafts. This research was funded by a Marie Curie International Outgoing Fellowship within the 7th European Community Framework Programme (project NON- BREEDERS). The contents of this paper reflect the views of the researchers, not the views of the European Commission. Data Accessibility R-code available from the Dryad Digital Repository: http://dx.doi.org/10.5061/dryad.t56cn (Lee, Reid & Beissinger, 2016).Peer reviewedPostprin
Computation of Casimir Interactions between Arbitrary 3D Objects with Arbitrary Material Properties
We extend a recently introduced method for computing Casimir forces between
arbitrarily--shaped metallic objects [M. T. H. Reid et al., Phys. Rev.
Lett._103_ 040401 (2009)] to allow treatment of objects with arbitrary material
properties, including imperfect conductors, dielectrics, and magnetic
materials. Our original method considered electric currents on the surfaces of
the interacting objects; the extended method considers both electric and
magnetic surface current distributions, and obtains the Casimir energy of a
configuration of objects in terms of the interactions of these effective
surface currents. Using this new technique, we present the first predictions of
Casimir interactions in several experimentally relevant geometries that would
be difficult to treat with any existing method. In particular, we investigate
Casimir interactions between dielectric nanodisks embedded in a dielectric
fluid; we identify the threshold surface--surface separation at which
finite--size effects become relevant, and we map the rotational energy
landscape of bound nanoparticle diclusters
Education in post-Reformation Scotland : Andrew Melville and the University of St Andrews, 1560-1606
Andrew Melville (1545-1622) was the leader of the Presbyterian wing of the Scottish
Kirk between 1574 and 1607, and he and his colleagues were a perpetual irritant to
James VI and I in his attempts to establish a royal and Episcopal dominance over the
Kirk. Yet much of Melvilleâs reputation has been based on the seventeenth-century
Presbyterian historical narratives written by the likes of James Melville (Andrewâs
nephew) and David Calderwood. These partisan accounts formed the basis of modern
historiography in Thomas MâCrieâs monumentally influential Life of Andrew Melville.
Modern historians broadly agree that Melvilleâs portrayal as a powerful and decisive
church leader in these narratives is greatly exaggerated, and that he was at best an
influential voice in the Kirk who was quickly marginalised by the adult James VI.
However, only James Kirk has commented at any length on Melvilleâs other role in
Jacobean Scotlandâthat of developing and reforming the Scottish universities.
Melville revitalised the near-defunct Glasgow University between 1574 and 1580, and
from 1580 to 1607 was principal of St Maryâs College, St Andrews, Scotlandâs only
divinity college. He was also rector of the University of St Andrews between 1590
and 1597. This thesis provides a detailed account of Melvilleâs personal role in the
reform and expansion of the Scottish universities. This includes an analysis of his
direct work at Glasgow, but focuses primarily on St Andrews, using the untapped
archival sources held there and at the Scottish National Library and Archives to create
a detailed picture of the development of the University after the Reformation. This
thesis also evaluates the intellectual content of Melvilleâs reform programme, both as
it developed during his time in Paris, Poitiers and Geneva, and as we see it in action in
St Andrews
Fluctuating surface-current formulation of radiative heat transfer: theory and applications
We describe a novel fluctuating-surface current formulation of radiative heat
transfer between bodies of arbitrary shape that exploits efficient and
sophisticated techniques from the surface-integral-equation formulation of
classical electromagnetic scattering. Unlike previous approaches to
non-equilibrium fluctuations that involve scattering matrices---relating
"incoming" and "outgoing" waves from each body---our approach is formulated in
terms of "unknown" surface currents, laying at the surfaces of the bodies, that
need not satisfy any wave equation. We show that our formulation can be applied
as a spectral method to obtain fast-converging semi-analytical formulas in
high-symmetry geometries using specialized spectral bases that conform to the
surfaces of the bodies (e.g. Fourier series for planar bodies or spherical
harmonics for spherical bodies), and can also be employed as a numerical method
by exploiting the generality of surface meshes/grids to obtain results in more
complicated geometries (e.g. interleaved bodies as well as bodies with sharp
corners). In particular, our formalism allows direct application of the
boundary-element method, a robust and powerful numerical implementation of the
surface-integral formulation of classical electromagnetism, which we use to
obtain results in new geometries, including the heat transfer between finite
slabs, cylinders, and cones
Survival Themed Video Games and Cultural Constructs of Power
Studies of the relationship between games and culture have often considered the empowering effect of games on the player. Studies have related this empowerment to individual character growth as well as broader geopolitical action (e.g., the conquering of nations). Few studies, however, have considered the emergent and increasingly popular survival genre of video games. In the current inquiry, through an analysis of past and current examples of games in this genre, we explore how survival games disempower players and discuss the potential implications for this shift in terms of cultural attitudes toward the current state of the world, individual prospects, and optimism/pessimism about the future. The goal of this piece is to explore and converse with the existing state of the literature and exemplars from the survival genre, creating a typological framework for future empirical and theoretical development in the area of games, culture, and (dis)empowerment dynamics
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