2,570,384 research outputs found
Roll function in a flight simulator
Method introduces roll into the flying-spot scanner by modifying the scanning waveforms
Moduli spaces of noncommutative instantons: gauging away noncommutative parameters
Using the theory of noncommutative geometry in a braided monoidal category,
we improve upon a previous construction of noncommutative families of
instantons of arbitrary charge on the deformed sphere S^4_\theta. We formulate
a notion of noncommutative parameter spaces for families of instantons and we
explore what it means for such families to be gauge equivalent, as well as
showing how to remove gauge parameters using a noncommutative quotient
construction. Although the parameter spaces are a priori noncommutative, we
show that one may always recover a classical parameter space by making an
appropriate choice of gauge transformation.Comment: v2: 44 pages; minor changes. To appear in Quart. J. Mat
S100B is increased in Parkinson’s disease and ablation protects against MPTP-induced toxicity through the RAGE and TNF-α pathway
Peer reviewedPublisher PD
Parkinson's disease dementia: a neural networks perspective.
In the long-term, with progression of the illness, Parkinson's disease dementia affects up to 90% of patients with Parkinson's disease. With increasing life expectancy in western countries, Parkinson's disease dementia is set to become even more prevalent in the future. However, current treatments only give modest symptomatic benefit at best. New treatments are slow in development because unlike the pathological processes underlying the motor deficits of Parkinson's disease, the neural mechanisms underlying the dementing process and its associated cognitive deficits are still poorly understood. Recent insights from neuroscience research have begun to unravel the heterogeneous involvement of several distinct neural networks underlying the cognitive deficits in Parkinson's disease dementia, and their modulation by both dopaminergic and non-dopaminergic transmitter systems in the brain. In this review we collate emerging evidence regarding these distinct brain networks to give a novel perspective on the pathological mechanisms underlying Parkinson's disease dementia, and discuss how this may offer new therapeutic opportunities
A study of the means of increasing the dynamic range of visual simulation by means of a flying-spot scanner Final report
Increasing dynamic range of visual simulation for pilots using flying spot scanne
Financial Engineering and Rationality: Experimental Evidence Based on the Monty Hall Problem
Financial engineering often involves redefining existing financial assets to create new financial products. This paper investigates whether financial engineering can alter the environment so that irrational agents can quickly learn to be rational. The specific environment we investigate is based on the Monty Hall problem, a well-studied choice anomaly. Our results show that, by the end of the experiment, the majority of subjects understand the Monty Hall anomaly. Average valuation of the experimental asset is very close to the expected value based on the true probabilities.experiment, behavioral finance
The Gysin Sequence for Quantum Lens Spaces
We define quantum lens spaces as `direct sums of line bundles' and exhibit
them as `total spaces' of certain principal bundles over quantum projective
spaces. For each of these quantum lens spaces we construct an analogue of the
classical Gysin sequence in K-theory. We use the sequence to compute the
K-theory of the quantum lens spaces, in particular to give explicit geometric
representatives of their K-theory classes. These representatives are
interpreted as `line bundles' over quantum lens spaces and generically define
`torsion classes'. We work out explicit examples of these classes.Comment: 27 pages. v2: No changes in the scientific content and results.
Section 5 completely re-written and a final section added; suppressed two
appendices; added references; minor changes throughout the paper. To appear
in the JNc
Understanding the Escalation of Brain Drain in Nigeria From Poor Leadership Point of View
Migration of people from one place to another in countries of the world in search of better conditions of living predates history.
It ignited western societies’ contact with Africa and the rest of the world. Prior the contact, agriculture was the main stay of Africa’s
economy. Thus, the movement of farmers from one location to another in search of fertile grounds for cultivation was in vogue. After
independence in Nigeria, cattle rearers are known for relocating from the North to South during dry season in search of green grass to
sustain their cattle and occupation. In the present day Nigeria, the same scenario still abounds but in a new dimension. It now involves
movement of highly skilled manpower from the country to developed societies. Among other things, this paper finds out if there is a
relationship between poor leadership of the country and escalation of brain drain. Simple percentage and ranking method was used to
analyze the study’s data. Chi-square was used to test its hypothesis. Our result revealed a relationship between poor leadership of the
country and brain drain. It equally indicated that students are interested in travelling out of the country to developed societies after their
study. Also from the study, twelve causes of brain drain were indentified. Some of them are: mass unemployment, poor salaries and
conditions of service, mass poverty, crises-religious, communal, political, education etc. In respect of effects of brain drain on the nation’s
economy, eleven factors were identified by the respondents. Some of them are: loss of human capital assets to man various institutions in
the country, loss of tax of migrated manpower to foreign countries, loss of capital invested in education of migrated manpower assets etc.
Finally, eleven solutions were profiled to the lingering problem of brain drain. The most important ones are: Good leadership, salary and
conditions of service as well as rewarding system for diligent staff, mass employment etc
Regional Strategies of Multinational Pharmaceutical Firms
This paper examines the R&D and strategies of the world’s largest firms in the pharmaceuticals sector and finds a high degree of intra-regional sales. R&D and sales are more concentrated within North America and Europe than in Asia. In addition, the relative size of the U.S. market, compared to other parts of the triad, creates imbalances with respect to R&D, sales and international strategy.
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Polymer Matrix Nanocomposites by Inkjet Printing
This paper describes work on a continuing project to form functional composites that contain
ceramic nanoparticles using a Solid Freeform Fabrication (SFF) inkjet printing method. The process
involves inkjet deposition of monomer/particle suspensions in layers followed by curing each layer in
sequence using UV radiation. The reactive monomer is hexanediol-diacrylate (HDODA); the polymer
forming reaction proceeds by a free radical mechanism. The liquid monomer containing nanoparticles
is essentially a printing ink formulation. Successfully suspending the particles in the monomer is
critical. We have developed a surface treatment method for forming stable suspensions of the
nanoparticles so that they remain discrete throughout the processing sequence.
The SFF process involves careful control of the polymer cure so that the interface between layers
is seamless and residual stresses in the composites are eliminated. An immediate use for such
composites is in optical applications as gradient refractive index lenses (GRIN). GRIN lenses have
planar surfaces, eliminating the need for costly grinding and polishing. The planar surfaces also
eliminate optical aberrations that result at the edges of spherical lenses and diminish the accuracy of
focus.
If the appropriate nanoparticles are fully dispersed they will modify the polymer's refractive index
without interfering with light transmission. The effect is additive with volume concentration. Using
'inks' of different compositions in a multiple nozzle inkjet printer allows the formation of composites
with precise composition gradients. Since an object is built one planar layer at a time, changes can be
made readily both within each layer and from layer to layer. Inkjet printing with picoliter resolution is
ideal for this task.
Working with SiC nanoparticles in HDODA as a model system for demonstrating the inkjet
deposition process, nanocomposite films with a linear concentration gradient varying from 0 to 4.5%
(wt) were fabricated on Silicon wafers. These composites are 30 layer films, which total 140µm in
thickness. Each layer in the composite is about 5 µm in thickness. Analytical methods for
characterizing the dispersion of the nanoparticles in the composite and some of the salient optical
properties of the composites also were established. The status of the program is reviewed in this
paper.Mechanical Engineerin
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