1,791 research outputs found
Technology Prizes for Climate Change Mitigation
We analyze whether technology inducement prizes could be a useful complement to standard research grants and contracts in developing climate change mitigation technologies. We find that there are important conceptual advantages to using inducement prizes in certain circumstances. These conceptual inferences are borne out by an examination of the track record of prizes inducing research into public goods, including relevant energy technologies. However, we also find that the prizes’ successes are contingent on their proper design. We analyze how several important design elements could influence the effectiveness of a climate technology prize.inducement prize, research and development, climate change, technology, policy
An Investigation of Void Fraction in the Stratified/Annular Flow Regions in Smooth, Horizontal Tubes
Refrigerants R134a and R410A have been used for void fraction measurements in smooth
horizontal tubes with diameters between 4mm and 7mm. Quality and mass flux were varied from
5% to 90% and 75 kglm2-s to 700 kglm2-s, respectively. Two test loops, one for condensing
flows at 35C and the other for evaporating flows at 5C, were used in the investigation. Results
show that near the transition from annular to stratified flow void fraction changed from viscousinertial
dependence to gravitational-inertial dominated dependence. An important feature
observed is the annular flow region's relative insensitivity to mass flux while the border region
between annular and stratified flows is characterized by strong mass flux dependence.Air Conditioning and Refrigeration Project 7
Stem cell models of human synapse development and degeneration
Many brain disorders exhibit altered synapse formation in development or syn- apse loss with age. To understand the complexities of human synapse development and degeneration, scientists now engineer neurons and brain organoids from human-induced pluripotent stem cells (hIPSC). These hIPSC-derived brain models develop both excitatory and inhibitory synapses and functional synaptic activity. In this review, we address the ability of hIPSC-derived brain models to recapitulate synapse development and insights gained into the molecular mechanisms underlying synaptic alterations in neuronal disorders. We also discuss the potential for more accurate human brain models to advance our understanding of synapse development, degeneration, and therapeutic responses
Stochastic Theory in the Strong Coupling Limit
The stochastic -theory in dimensions dynamically develops domain
wall structures within which the order parameter is not continuous. We develop
a statistical theory for the -theory driven with a random forcing which
is white in time and Gaussian-correlated in space. A master equation is derived
for the probability density function (PDF) of the order parameter, when the
forcing correlation length is much smaller than the system size, but much
larger than the typical width of the domain walls. Moreover, exact expressions
for the one-point PDF and all the moments are given. We then
investigate the intermittency issue in the strong coupling limit, and derive
the tail of the PDF of the increments . The scaling laws
for the structure functions of the increments are obtained through numerical
simulations. It is shown that the moments of field increments defined by,
, behave as , where
for , and for Comment: 22 pages, 6 figures. to appear in Nuclear. Phys.
New perspectives on the Ising model
The Ising model, in presence of an external magnetic field, is isomorphic to
a model of localized interacting particles satisfying the Fermi statistics. By
using this isomorphism, we construct a general solution of the Ising model
which holds for any dimensionality of the system. The Hamiltonian of the model
is solved in terms of a complete finite set of eigenoperators and eigenvalues.
The Green's function and the correlation functions of the fermionic model are
exactly known and are expressed in terms of a finite small number of parameters
that have to be self-consistently determined. By using the equation of the
motion method, we derive a set of equations which connect different spin
correlation functions. The scheme that emerges is that it is possible to
describe the Ising model from a unified point of view where all the properties
are connected to a small number of local parameters, and where the critical
behavior is controlled by the energy scales fixed by the eigenvalues of the
Hamiltonian. By using algebra and symmetry considerations, we calculate the
self-consistent parameters for the one-dimensional case. All the properties of
the system are calculated and obviously agree with the exact results reported
in the literature.Comment: 19 RevTeX pages, 9 panels, to be published in Eur. Phys. J.
Selection, Stability and Renormalization
We illustrate how to extend the concept of structural stability through
applying it to the front propagation speed selection problem. This
consideration leads us to a renormalization group study of the problem. The
study illustrates two very general conclusions: (1) singular perturbations in
applied mathematics are best understood as renormalized perturbation methods,
and (2) amplitude equations are renormalization group equations.Comment: 38 pages, LaTeX, two PostScript figures available by anonymous ftp to
gijoe.mrl.uiuc.edu (128.174.119.153) files /pub/front_kkfest_fig
Representation recovers information
Early agreement within cognitive science on the topic of representation has now given way to a combination of positions. Some question the significance of representation in cognition. Others continue to argue in favor, but the case has not been demonstrated in any formal way. The present paper sets out a framework in which the value of representation-use can be mathematically measured, albeit in a broadly sensory context rather than a specifically cognitive one. Key to the approach is the use of Bayesian networks for modeling the distal dimension of sensory processes. More relevant to cognitive science is the theoretical result obtained, which is that a certain type of representational architecture is *necessary* for achievement of sensory efficiency. While exhibiting few of the characteristics of traditional, symbolic encoding, this architecture corresponds quite closely to the forms of embedded representation now being explored in some embedded/embodied approaches. It becomes meaningful to view that type of representation-use as a form of information recovery. A formal basis then exists for viewing representation not so much as the substrate of reasoning and thought, but rather as a general medium for efficient, interpretive processing
Akns Hierarchy, Self-Similarity, String Equations and the Grassmannian
In this paper the Galilean, scaling and translational self--similarity
conditions for the AKNS hierarchy are analysed geometrically in terms of the
infinite dimensional Grassmannian. The string equations found recently by
non--scaling limit analysis of the one--matrix model are shown to correspond to
the Galilean self--similarity condition for this hierarchy. We describe, in
terms of the initial data for the zero--curvature 1--form of the AKNS
hierarchy, the moduli space of these self--similar solutions in the Sato
Grassmannian. As a byproduct we characterize the points in the Segal--Wilson
Grassmannian corresponding to the Sachs rational solutions of the AKNS equation
and to the Nakamura--Hirota rational solutions of the NLS equation. An explicit
1--parameter family of Galilean self--similar solutions of the AKNS equation
and the associated solution to the NLS equation is determined.Comment: 25 pages in AMS-LaTe
What explains the uneven take-up of ISO 14001 at the global level?: a panel-data analysis
Since its release in the mid-1990s, close to 37 000 facilities have been certified to ISO 14001, the international voluntary standard for environmental management systems. Yet, despite claims that the standard can be readily adapted to very different corporate and geographic settings, its take-up has been highly geographically variable. This paper contributes to a growing body of work concerned with explaining the uneven diffusion of ISO 14001 at the global level. Drawing from the existing theoretical and empirical literature we develop a series of hypotheses about how various economic, market, and regulatory factors influence the national count of ISO 14001 certifications. These hypotheses are then tested using econometric estimation techniques with data for a panel of 142 developed and developing countries. We find that per capita ISO 14001 counts are positively correlated with income per capita, stock of foreign direct investment, exports of goods and services to Europe and Japan, and pressure from civil society. Conversely, productivity and levels of state intervention are negatively correlated. The paper finishes by offering a number of recommendations to policymakers concerned with accelerating the diffusion of voluntary environmental standards
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