9,034 research outputs found
Discharge characteristics of dielectric materials examined in mono-, dual-, and spectral energy electron charging environments
The effects of midenergy electrons on the charge and discharge characteristics of spacecraft dielectric materials and the data base from which basic discharge models can be formulated is expanded. Thin dielectric materials were exposed to low, mid combined low and mid, and spectral energy electron environments. Three important results are presented: (1) it determined electron environments that lead to dielectric discharges at potentials less negative than -5 kV; (2) two types of discharges were identified that dominate the kinds of discharges seen; and (3) it is shown that, for the thin dielectric materials tested, the worst-case discharges observed in the various environments are similar
Computing the output distribution and selection probabilities of a stack filter from the DNF of its positive Boolean function
Many nonlinear filters used in practise are stack filters. An algorithm is
presented which calculates the output distribution of an arbitrary stack filter
S from the disjunctive normal form (DNF) of its underlying positive Boolean
function. The so called selection probabilities can be computed along the way.Comment: This is the version published in Journal of Mathematical Imaging and
Vision, online first, 1 august 201
Future research perspectives on environment and health: the requirement for a more expansive concept of translational cancer research
The last two decades have seen exciting advances in understanding the human genome, aided by the development of powerful analytical laboratory tools. These advances have enabled genome-wide association studies to link specific genetic variants with an altered risk of cancer. Unfortunately there has not been an analogous refinement of tools on such a comprehensive scale to permit an equally thorough investigation of environmental factors, yet it is known that these play a major role in cancer etiology. This limitation led to the suggested need for an exposome to match the genome. Major advances both in understanding mechanisms of carcinogenesis as well as in the technology to investigate these underlying steps in the disease process offer the potential to redress this imbalance between exposome and genome. This is all the more important in order to fully exploit the large prospective cohort studies with biological specimens now being established to investigate the environmental and genetic basis of common chronic diseases. Currently translational cancer research is understood to equate to a âbench to bedsideâ process, focused on improved clinical management of cancer. Unfortunately, alone, this is an inadequate response to the growing burden of cancer worldwide. Priority also needs to be placed on understanding the causes of cancer, its prevention and, critically, how to implement promising interventions into health care structures. The need therefore is to translate basic science to the population in parallel to the translation into the clinic. This âtwo-wayâ translational cancer research encourages the common soil of basic science to be applied both to the prevention of cancer and to its treatment. In this way the notable advances in relation to carcinogenesis will yield a richer benefit to society through balanced initiatives to understand the causes and prevention of cancer in addition to more effective treatment and care of those people developing the disease
Remote manipulator dynamic simulation
A simulator to generate the real time visual scenes required to perform man in the loop investigations of remote manipulator application and design concepts for the space shuttle is described. The simulated remote manipulator consists of a computed display system that uses a digital computer, the electronic scene generator, an operator's station, and associated interface hardware. A description of the capabilities of the implemented simulation is presented. The mathematical models and programs developed for the simulation are included
Diamond Integrated Optomechanical Circuits
Diamond offers unique material advantages for the realization of micro- and
nanomechanical resonators due to its high Young's modulus, compatibility with
harsh environments and superior thermal properties. At the same time, the wide
electronic bandgap of 5.45eV makes diamond a suitable material for integrated
optics because of broadband transparency and the absence of free-carrier
absorption commonly encountered in silicon photonics. Here we take advantage of
both to engineer full-scale optomechanical circuits in diamond thin films. We
show that polycrystalline diamond films fabricated by chemical vapour
deposition provide a convenient waferscale substrate for the realization of
high quality nanophotonic devices. Using free-standing nanomechanical
resonators embedded in on-chip Mach-Zehnder interferometers, we demonstrate
efficient optomechanical transduction via gradient optical forces. Fabricated
diamond resonators reproducibly show high mechanical quality factors up to
11,200. Our low cost, wideband, carrier-free photonic circuits hold promise for
all-optical sensing and optomechanical signal processing at ultra-high
frequencies
Scaffold searching: automated identification of similar ring systems for the design of combinatorial libraries
Rigid ring systems can be used to position receptor-binding functional groups in 3D space and they thus play an increasingly important role in the design of combinatorial libraries. This paper discusses the use of shape-similarity methods to identify ring systems that are structurally similar to, and aligned with, a user-defined target ring system. These systems can be used as alternative scaffolds for the construction of a combinatorial library
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