18,821 research outputs found
The 50-horsepower solar-powered irrigation facility located near Gila Bend, Arizona
The 50 horsepower solar powered irrigation facility near Gila Bend, Arizona which includes a Rankine cycle demonstrates the technical feasibility of solar powered pumping. The design of a facility specifically for the irrigation farmer using the technology that has been developed over the last four years is proposed
Signals from the 4th Dimension: Role of Extracellular Matrix Signaling in Synaptic Plasticity Mediating Addiction
Chronic cocaine abuse causes maladaptive neuroadaptations that underlie vulnerability to relapse, even after protracted abstinence. A great deal of work has examined mechanisms of neuroplasticity by which these occur. However, the majority of experimentation has focused on intracellular signaling cascades, while the extracellular compartment has been largely ignored. In the past decade, work has emerged in the learning and memory literature that indicates that extracellular matrix remodeling and signaling is required for adaptive forms of neuroplasticity (e.g. learning and memory), although it has not been thoroughly examined in models of maladaptive neuroplasticity. Throughout this dissertation a drug self-administration, extinction and reinstatement paradigm is used. I first examine the role of the matrix metalloproteinases (MMPs) in the nucleus accumbens core (NAcore) in both the persistent synaptic potentiation that occurs following extinction of cocaine self-administration, and in the rapid, transient potentiation that is required for cue-induced reinstatement. By measuring both the expression and activity of MMPs, this work shows that relapse to multiple classes of drugs of abuse (cocaine, nicotine, and heroin) each are accompanied by an induction of MMP activity. Furthermore, this work goes on to show that inhibiting MMP activity also reverses or blocks synaptic potentiation. A second set of experiments examines nitric oxide (NO) signaling as a mechanism of MMP activation. These experiments used biochemical examination of neuronal nitric oxide synthase (nNOS) activity following extinction and reinstatement of cocaine seeking, and a small molecule inhibitor of nNOS to determine the effects of nNOS activity on MMP activity and relapse behavior. Finally, by using NOS1-Cre transgenic mice this work shows that selectively chemogenetically stimulating a small population of interneurons that express nNOS drives reinstatement of drug seeking. This dissertation concludes that nNOS-expressing interneurons may comprise a ‘master-switch’ by MMPs are activated, synapses are potentiated, and strongly motivated behaviors are initiated
Post-aragonite phases of CaCO at lower mantle pressures
The stability, structure and properties of carbonate minerals at lower mantle
conditions has significant impact on our understanding of the global carbon
cycle and the composition of the interior of the Earth. In recent years, there
has been significant interest in the behavior of carbonates at lower mantle
conditions, specifically in their carbon hybridization, which has relevance for
the storage of carbon within the deep mantle. Using high-pressure synchrotron
X-ray diffraction in a diamond anvil cell coupled with direct laser heating of
CaCO using a CO laser, we identify a crystalline phase of the
material above 40 GPa corresponding to a lower mantle depth of around 1,000
km which has first been predicted by \textit{ab initio} structure
predictions. The observed carbon hybridized species at 40 GPa is
monoclinic with symmetry and is stable up to 50 GPa, above which it
transforms into a structure which cannot be indexed by existing known phases. A
combination of \textit{ab initio} random structure search (AIRSS) and
quasi-harmonic approximation (QHA) calculations are used to re-explore the
relative phase stabilities of the rich phase diagram of CaCO. Nudged
elastic band (NEB) calculations are used to investigate the reaction mechanisms
between relevant crystal phases of CaCO and we postulate that the mineral
is capable of undergoing - hybridization change purely in the
structure forgoing the accepted post-aragonite structure.Comment: 12 pages, 8 figure
Technique for the Measurement of the In-Situ Development Rate
In the past, a Perkin Elmer Development Rate Monitor (DRM) has been used to measure the development rate of photoresist. However, due to several limitations of the DRM, the development rates measured therein, are not truly representative of the resist processing on a production lire. Subtleties in the development system are not obtained through the DRM and hence an in-situ development rate is required. Using a Site Services Development Spray Monitor (DSM 100) and a post processing algorithm. the in-situ measured development rates were obtained. The interference signals for eight different wavelengths were simultaneously monitored on a pattemed wafer as it spun on the development module of a wafer track. Since the interference signal is generated from a circularly polarized light source, the DSM 100 has demonstrated robustness to the red cloud effect, developer spray, bubbles in the developer, and ambient light.\u27 Two algorithms for the calculation of the in-situ development rate are proposed. After collecting the eight interference curves, these post processing algorithms used the Marquardt Levenberg non-linear regression algorithm and a linear regression approach to find the development rate as a function of development time. Although the standing wave effect was visible in the plots of development rate versus time using both techniques, the first approach generated the better curve. A plot of development rate versus depth was generated via numerical integration of the plot of development rate versus time. Since the only equation used in the post processing algorithm is the interference relationship, this technique is equally well suited for other types of exposure and resist chemistries. Possession of the in-situ development rate could provide further insight into resist development mechanisms, the development of better models, and the extraction of photolithography model parameters that are specific to the production process
State-to-state rate coefficients for transfer from the rotational levels J = 7.5, 20.5, 31.5 and 40.5 in NO(X <sup>2</sup>II( 1/2 ), v = 2) in collisions with He, Ar and N<sub>2</sub> and for J = 7.5, 20.5 and 31.5 in collisions with NO:Comparisons between experiment and theory
Statistical Computations with AstroGrid and the Grid
We outline our first steps towards marrying two new and emerging
technologies; the Virtual Observatory (e.g, AstroGrid) and the computational
grid. We discuss the construction of VOTechBroker, which is a modular software
tool designed to abstract the tasks of submission and management of a large
number of computational jobs to a distributed computer system. The broker will
also interact with the AstroGrid workflow and MySpace environments. We present
our planned usage of the VOTechBroker in computing a huge number of n-point
correlation functions from the SDSS, as well as fitting over a million CMBfast
models to the WMAP data.Comment: Invited talk to appear in "Proceedings of PHYSTAT05: Statistical
Problems in Particle Physics, Astrophysics and Cosmology
Lift-and-Round to Improve Weighted Completion Time on Unrelated Machines
We consider the problem of scheduling jobs on unrelated machines so as to
minimize the sum of weighted completion times. Our main result is a
-approximation algorithm for some fixed , improving upon the
long-standing bound of 3/2 (independently due to Skutella, Journal of the ACM,
2001, and Sethuraman & Squillante, SODA, 1999). To do this, we first introduce
a new lift-and-project based SDP relaxation for the problem. This is necessary
as the previous convex programming relaxations have an integrality gap of
. Second, we give a new general bipartite-rounding procedure that produces
an assignment with certain strong negative correlation properties.Comment: 21 pages, 4 figure
Reverse Innovation: An Opportunity for Strengthening Health Systems
BACKGROUND: Canada, when compared to other OECD countries, ranks poorly with respect to innovation and innovation adoption while struggling with increasing health system costs. As a result of its failure to innovate, the Canadian health system will struggle to meet the needs and demands of both current and future populations. The purpose of this initiative was to explore if a competition-based reverse innovation challenge could mobilize and stimulate current and future leaders to identify and lead potential reverse innovation projects that address health system challenges in Canada.
METHODS: An open call for applications took place over a 4-month period. Applicants were enticed to submit to the competition with a $50,000 prize for the top submission to finance their project. Leaders from a wide cross-section of sectors collectively developed evaluation criteria and graded the submissions. The criteria evaluated: proof of concept, potential value, financial impact, feasibility, and scalability as well as the use of prize money and innovation team.
RESULTS: The competition received 12 submissions from across Canada that identified potential reverse innovations from 18 unique geographical locations that were considered developing and/or emerging markets. The various submissions addressed health system challenges relating to education, mobile health, aboriginal health, immigrant health, seniors health and women\u27s health and wellness. Of the original 12 submissions, 5 finalists were chosen and publically profiled, and 1 was chosen to receive the top prize.
CONCLUSIONS: The results of this initiative demonstrate that a competition that is targeted to reverse innovation does have the potential to mobilize and stimulate leaders to identify reverse innovations that have the potential for system level impact. The competition also provided important insights into the capacity of Canadian students, health care providers, entrepreneurs, and innovators to propose and implement reverse innovation in the context of the Canadian health system
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