401 research outputs found
The RICO Act: Its Seventh Inning Stretch
Article published in the Michigan State University School of Law Student Scholarship Collection
Scalable iterative methods for sampling from massive Gaussian random vectors
Sampling from Gaussian Markov random fields (GMRFs), that is multivariate
Gaussian ran- dom vectors that are parameterised by the inverse of their
covariance matrix, is a fundamental problem in computational statistics. In
this paper, we show how we can exploit arbitrarily accu- rate approximations to
a GMRF to speed up Krylov subspace sampling methods. We also show that these
methods can be used when computing the normalising constant of a large
multivariate Gaussian distribution, which is needed for both any
likelihood-based inference method. The method we derive is also applicable to
other structured Gaussian random vectors and, in particu- lar, we show that
when the precision matrix is a perturbation of a (block) circulant matrix, it
is still possible to derive O(n log n) sampling schemes.Comment: 17 Pages, 4 Figure
Three-dimensional low Reynolds number flows near biological filtering and protective layers
Mesoscale filtering and protective layers are replete throughout the natural
world. Within the body, arrays of extracellular proteins, microvilli, and cilia
can act as both protective layers and mechanosensors. For example, blood flow
profiles through the endothelial surface layer determine the amount of shear
stress felt by the endothelial cells and may alter the rates at which molecules
enter and exit the cells. Characterizing the flow profiles through such layers
is therefore critical towards understanding the function of such arrays in cell
signaling and molecular filtering. External filtering layers are also important
to many animals and plants. Trichomes (the hairs or fine outgrowths on plants)
can drastically alter both the average wind speed and profile near the leaf's
surface, affecting the rates of nutrient and heat exchange. In this paper,
dynamically scaled physical models are used to study the flow profiles outside
of arrays of cylinders that represent such filtering and protective layers. In
addition, numerical simulations using the Immersed Boundary Method are used to
resolve the 3D flows within the layers. The experimental and computational
results are compared to analytical results obtained by modeling the layer as a
homogeneous porous medium with free flow above the layer. The experimental
results show that the bulk flow is well described by simple analytical models.
The numerical results show that the spatially averaged flow within the layer is
well described by the Brinkman model. The numerical results also demonstrate
that the flow can be highly 3D with fluid moving into and out of the layer.
These effects are not described by the Brinkman model and may be significant
for biologically relevant volume fractions. The results of this paper can be
used to understand how variations in density and height of such structures can
alter shear stresses and bulk flows.Comment: 28 pages, 10 figure
Funding and financing urban infrastructure : a UK-US comparison
PhD ThesisThis thesis examines how urban infrastructure is funded and financed in cities in the United Kingdom and the United States. The thesis brings together the diverse and disconnected literatures on infrastructure, capital investment and urban development and creates a framework for understanding the changing landscape of infrastructure finance. Drawing on primary empirical research, this framework is then used to examine the funding and financing of infrastructure in the cities of Manchester, Newcastle and Sheffield in the UK and Buffalo, NY, Chicago, IL, and Stockton, CA in the US. The objectives of the empirical analysis are: to explain the types of funding and financing being used within the case study cities and to identify emergent trends; to understand the multiscalar factors driving the adoption and use of those practices; to analyse the key mechanisms, processes and systems that are implicit in a range of capital investment strategies; and to explain the implications of the ways in which infrastructure is funded and financed for urban development within the case study cities.
This thesis argues that the practices used for funding and financing infrastructure in cities are becoming increasingly financialised, and that this is having transformative implications for the urban environment. As such, the thesis makes four main contributions; first, it demonstrates how the process of financialisation is changing the ways in which infrastructure is funded and financed; second, it shows that financialisation is changing the politics of infrastructure and fuelling a process of reterritorialisation but, at the same time, that the state continues to have a major role in the funding and financing of infrastructure; third, it contends that the financialisation of capital investment is encouraged by instances of fiscal stress, and yet that it can also catalyse overaccumulation and cause further fiscal crisis; and fourth, it suggests that increasingly financialised models of infrastructure investment are reinforcing patterns of uneven development and causing an intensification in the process of urban splintering.
More broadly, this research begins to address a gap in the literature on financialisation, which, to date, has been criticised for lacking sufficiently in-depth and fine-grained analyses of financial actors, markets and systems. In particular, the empirical evidence and comparative case study analysis illustrates that financialisation is not an overpowering and all-consuming behemoth but a highly variable process that is negotiated, managed and regulated in different ways in different geographical contexts
The Way of the Artist Educator: Understanding the Fusion of Artistic Studio Practice and Teaching Pedagogy of K-12 Visual Arts Educators
The purpose of this autoethnographic study was to examine the experiences of Artist Educators and how they perceive the fusion of their artistic studio practice and teaching pedagogy impacts their creative and teaching practices. This study involved a focus group of six individuals, including the researcher. All the participants were practicing artists, currently employed or recently retired K-12 Visual Arts Education certified in the states of Maine or New Hampshire and members of the Kittery Art Association. This study used a combination of interviews and an arts-based method for data collection. All the data were analyzed and resulted in the following seven findings: (1) The identity of an Artist Educator is synchronized with a call to a vocation.
(2) The necessity to create art and teach art simultaneously was intrinsic for Artist Educators. (3) Artist Educators lived a creative life and believed it to be a personal practice that cannot be taught. (4) Both extrinsic and intrinsic factors and conditions can inhibit an Artist Educator’s practice. (5) Both intrinsic and extrinsic factors and conditions supported the practice of an Artist Educator. (6) Artist Educators cultivated quality relationships for teaching and learning by fusing their artistic studio practice and teaching pedagogy. (7) Artist Educators fostered life lessons and embodied wisdom from the fusion of their artistic studio practice and teaching pedagogy. These findings and insights acquired have implications for visual arts education practice and arts educator professional development programs. The Way of the Artist Educator paradigm offers an alternative approach for a quality and holistic 21st Century Visual Arts Education.
Key words: Artist Educator, identity, motivation, creativity, fusion, practic
IB2d : a Python and MATLAB implementation of the immersed boundary method
The development of fluid-structure interaction (FSI) software involves trade-offs between ease of use, generality, performance, and cost. Typically there are large learning curves when using low-level software to model the interaction of an elastic structure immersed in a uniform density fluid. Many existing codes are not publicly available, and the commercial software that exists usually requires expensive licenses and may not be as robust or allow the necessary flexibility that in house codes can provide. We present an open source immersed boundary software package, IB2d, with full implementations in both MATLAB and Python, that is capable of running a vast range of biomechanics models and is accessible to scientists who have experience in high-level programming environments. IB2d contains multiple options for constructing material properties of the fiber structure, as well as the advection-diffusion of a chemical gradient, muscle mechanics models, and artificial forcing to drive boundaries with a preferred motion
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