23,513 research outputs found
Unspeakable Suffering; Eloquent Explanations: National Civil War Medicine Museumâs 26th Annual Conference
On Friday, October 12th, 2018, the National Civil War Medicine Museum kicked off its 26th annual conference and began its three-day event with a series of lectures on topics ranging from Confederate medical practice to cultural understandings of cowardice. A series of unique lectures given by a professionally diverse cast of presenters illuminated the often-peripheral field of Civil War Medicine. [excerpt
Making Photographs Speak
It has often been said that âa picture is worth a thousand words.â Making that picture spit out those mythical thousand words, as we can all attest, is no easy task. Over the course of the first half of the fall semester, the three of us were tasked with developing brief interpretive captions for two Civil War photographs each, with the end goal to display our work at the Civil War Instituteâs 2019 Summer Conference. What initially appeared as a simple project quickly revealed itself to be a difficult, yet rewarding, challenge that taught us all important lessons concerning history, photography, and writing that we will not soon forget. Producing the photography exhibit enhanced our skills as historical writers, introduced us to the challenge of writing for a popular audience, and deepened our understanding of Civil War photography. [excerpt
Very-large-scale motions in rough-bed open-channel flow
Acknowledgements The study has been supported by two EPSRC/UK grants, âHigh-resolution numerical and experimental studies of turbulence-induced sediment erosion and near-bed transportâ (EP/G056404/1) and âBed friction in rough-bed free-surface flows: a theoretical framework, roughness regimes, and quantificationâ (EP/K041169/1). Discussions with I. Marusic and comments of three anonymous reviewers are greatly appreciated.Peer reviewedPublisher PD
The Complexity of the List Partition Problem for Graphs
The k-partition problem is as follows: Given a graph G and a positive integer k, partition the vertices of G into at most k parts A1, A2, . . . , Ak, where it may be specified that Ai induces a stable set, a clique, or an arbitrary subgraph, and pairs Ai, Aj (iâ j) be completely nonadjacent, completely adjacent, or arbitrarily adjacent. The list k-partition problem generalizes the k-partition problem by specifying for each vertex x, a list L(x) of parts in which it is allowed to be placed. Many well-known graph problems can be formulated as list k-partition problems: e.g., 3-colorability, clique cutset, stable cutset, homogeneous set, skew partition, and 2-clique cutset. We classify, with the exception of two polynomially equivalent problems, each list 4-partition problem as either solvable in polynomial time or NP-complete. In doing so, we provide polynomial-time algorithms for many problems whose polynomial-time solvability was open, including the list 2-clique cutset problem. This also allows us to classify each list generalized 2-clique cutset problem and list generalized skew partition problem as solvable in polynomial time or NP-complete
Observing and modeling the poloidal and toroidal fields of the solar dynamo
Context. The solar dynamo consists of a process that converts poloidal field
to toroidal field followed by a process which creates new poloidal field from
the toroidal field.
Aims. Our aim is to observe the poloidal and toroidal fields relevant to the
global solar dynamo and see if their evolution is captured by a
Babcock-Leighton dynamo.
Methods. We use synoptic maps of the surface radial field from the KPNSO/VT
and SOLIS observatories to construct the poloidal field as a function of time
and latitude, and Wilcox Solar Observatory and SOHO/MDI full disk images to
infer the longitudinally averaged surface azimuthal field. We show that the
latter is consistent with an estimate of that due to flux emergence and
therefore closely related to the subsurface toroidal field.
Results. We present maps of the poloidal and toroidal magnetic field of the
global solar dynamo. The longitude-averaged azimuthal field observed at the
surface results from flux emergence. At high latitudes this component follows
the radial component of the polar fields with a short time lag (1-3 years). The
lag increases at lower latitudes. The observed evolution of the poloidal and
toroidal magnetic fields is described by the (updated) Babcock-Leighton dynamo
model.Comment: A&
The Role of Subsurface Flows in Solar Surface Convection: Modeling the Spectrum of Supergranular and Larger Scale Flows
We model the solar horizontal velocity power spectrum at scales larger than
granulation using a two-component approximation to the mass continuity
equation. The model takes four times the density scale height as the integral
(driving) scale of the vertical motions at each depth. Scales larger than this
decay with height from the deeper layers. Those smaller are assumed to follow a
Kolomogorov turbulent cascade, with the total power in the vertical convective
motions matching that required to transport the solar luminosity in a mixing
length formulation. These model components are validated using large scale
radiative hydrodynamic simulations. We reach two primary conclusions: 1. The
model predicts significantly more power at low wavenumbers than is observed in
the solar photospheric horizontal velocity spectrum. 2. Ionization plays a
minor role in shaping the observed solar velocity spectrum by reducing
convective amplitudes in the regions of partial helium ionization. The excess
low wavenumber power is also seen in the fully nonlinear three-dimensional
radiative hydrodynamic simulations employing a realistic equation of state.
This adds to other recent evidence suggesting that the amplitudes of large
scale convective motions in the Sun are significantly lower than expected.
Employing the same feature tracking algorithm used with observational data on
the simulation output, we show that the observed low wavenumber power can be
reproduced in hydrodynamic models if the amplitudes of large scale modes in the
deep layers are artificially reduced. Since the large scale modes have reduced
amplitudes, modes on the scale of supergranulation and smaller remain important
to convective heat flux even in the deep layers, suggesting that small scale
convective correlations are maintained through the bulk of the solar convection
zone.Comment: 36 pages, 6 figure
Design for social innovation and inclusion.
Designing out crime is a strategy that the UK Design Council continues to profile and support, promoting the use of design as an approach for addressing social challenges and combating crime (UK Design Council 2011). This paper considers the strategy and application of design for social innovation to create an inclusive platform for participation in city locations where youth activity isn't otherwise encouraged. Design and diversionary activities can enhance wellness and contribute to healthier urban communities and these are the issues that Streetsport, an innovative diversionary tactics initiative, has sought to address. As a pilot project that grew into an established programme, Streetsport has proved itself as a vehicle of engagement that uses sport and creative activities to divert and distract disaffected young people (who are considered at risk of offending) from the pressures and challenging circumstances within their communities. Measures of the programme's impact are notable with reductions in both incidents of youth crime and complaints of youth anti-social behaviour in some instances down by over 50%. This paper describes the development of the Streetsport programme that began as a key partnership between Gray's School of Art, Grampian Police and RGU:Sport, with Designers playing a pivotal role in establishing and developing the strategy, for placing a mobile sports and activity arena and for making it visible both digitally (through branding and social media) and on location. Likened to a Trojan Horse, the temporary installation is deployed into the community at targeted strategic sites across Aberdeen city which include seven priority neighbourhoods reported by the Scottish Government as being in the 15% most deprived areas of Scotland (Scottish Index of Multiple Deprivation 2009). As a result of this project, the key stakeholders involved now recognise and value the role of design and designers in developing, implementing and communicating youth services. This paper serves as a case study of how design can be applied to facilitate community engagement and how designers can apply their skills specifically to engage disaffected youth through community-based activities
High magnetic field studies of the Vortex Lattice structure in YBa2Cu3O7
We report on small angle neutron scattering measurements of the vortex
lattice in twin-free YBa2Cu3O7, extending the previously investigated maximum
field of 11~T up to 16.7~T with the field applied parallel to the c axis. This
is the first microscopic study of vortex matter in this region of the
superconducting phase. We find the high field VL displays a rhombic structure,
with a field-dependent coordination that passes through a square configuration,
and which does not lock-in to a field-independent structure. The VL pinning
reduces with increasing temperature, but is seen to affect the VL correlation
length even above the irreversibility temperature of the lattice structure. At
high field and temperature we observe a melting transition, which appears to be
first order, with no detectable signal from a vortex liquid above the
transition
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