30,401 research outputs found

    A combined R-matrix eigenstate basis set and finite-differences propagation method for the time-dependent Schr\"{od}dinger equation: the one-electron case

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    In this work we present the theoretical framework for the solution of the time-dependent Schr\"{o}dinger equation (TDSE) of atomic and molecular systems under strong electromagnetic fields with the configuration space of the electron's coordinates separated over two regions, that is regions II and IIII. In region II the solution of the TDSE is obtained by an R-matrix basis set representation of the time-dependent wavefunction. In region IIII a grid representation of the wavefunction is considered and propagation in space and time is obtained through the finite-differences method. It appears this is the first time a combination of basis set and grid methods has been put forward for tackling multi-region time-dependent problems. In both regions, a high-order explicit scheme is employed for the time propagation. While, in a purely hydrogenic system no approximation is involved due to this separation, in multi-electron systems the validity and the usefulness of the present method relies on the basic assumption of R-matrix theory, namely that beyond a certain distance (encompassing region II) a single ejected electron is distinguishable from the other electrons of the multi-electron system and evolves there (region II) effectively as a one-electron system. The method is developed in detail for single active electron systems and applied to the exemplar case of the hydrogen atom in an intense laser field.Comment: 13 pages, 6 figures, submitte

    Promulgating Requirements for Admission to Prosecute Patent Applications

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    Among federal agencies, the U. S. Patent and Trademark Office is unique in its ability to require attorneys to submit to special requirements, such as passing a six hour examination, before being permitted to practice before it in patent cases. Indeed, the Supreme Court has held that an individual so admitted to practice before the PTO need not comply with state requirements otherwise applicable to those practicing law. The first part of this article discusses how this requirement came to be. It then discusses how the PTO determines whether an individual is fit to sit for the patent examination, focusing particularly on provisions contained in a bulletin mailed by its Office of Enrollment and Discipline (OED) to all would-be patent practitioners. It also briefly discusses rule-making requirements (and exceptions) generally applicable to federal agencies and examines the nature of the aforesaid provisions intended to affect admission to prosecute patent applications. This article concludes that the detailed provisions sent to applicants, fitting none of the rule-making exceptions, should be promulgated in accordance with the Administrative Procedure Act. It also concludes that, in the meantime, those provisions should not be regarded as binding on applicants to practice before the PTO in patent cases. Finally, the article contains an appendix that should be of particular interest to persons involved with software patents

    High Voltage CMOS Control Interface for Astronomy - Grade Charged Coupled Devices

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    The Pan-STARRS telescope consists of an array of smaller mirrors viewed by a Gigapixel arrays of CCDs. These focal planes employ Orthogonal Transfer CCDs (OTCCDs) to allow on-chip image stabilization. Each OTCCD has advanced logic features that are controlled externally. A CMOS Interface Device for High Voltage has been developed to provide the appropiate voltage signal levels from a readout and control system designated STARGRASP. OTCCD chip output levels range from -3.3V to 16.7V, with two different output drive strenghts required depending on load capacitance (50pF and 1000pF), with 24mA of drive and a rise time on the order of 100ns. Additional testing ADC structures have been included in this chip to evaluate future functional additions for a next version of the chip.Comment: 13 pages, 17 gigure

    Guided-wave approaches to spectrally selective energy absorption

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    Results of experiments designed to demonstrate spectrally selective absorption in dielectric waveguides on semiconductor substrates are reported. These experiments were conducted with three waveguides formed by sputtering films of PSK2 glass onto silicon-oxide layers grown on silicon substrates. The three waveguide samples were studied at 633 and 532 nm. The samples differed only in the thickness of the silicon-oxide layer, specifically 256 nm, 506 nm, and 740 nm. Agreement between theoretical predictions and measurements of propagation constants (mode angles) of the six or seven modes supported by these samples was excellent. However, the loss measurements were inconclusive because of high scattering losses in the structures fabricated (in excess of 10 dB/cm). Theoretical calculations indicated that the power distribution among all the modes supported by these structures will reach its steady state value after a propagation length of only 1 mm. Accordingly, the measured loss rates were found to be almost independent of which mode was initially excited. The excellent agreement between theory and experiment leads to the conclusion that low loss waveguides confirm the predicted loss rates

    Improved charge injection device and a focal plane interface electronics board for stellar tracking

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    An improved Charge Injection Device (CID) stellar tracking sensor and an operating sensor in a control/readout electronics board were developed. The sensor consists of a shift register scanned, 256x256 CID array organized for readout of 4x4 subarrays. The 4x4 subarrays can be positioned anywhere within the 256x256 array with a 2 pixel resolution. This allows continuous tracking of a number of stars simultaneously since nine pixels (3x3) centered on any star can always be read out. Organization and operation of this sensor and the improvements in design and semiconductor processing are described. A hermetic package incorporating an internal thermoelectric cooler assembled using low temperature solders was developed. The electronics board, which contains the sensor drivers, amplifiers, sample hold circuits, multiplexer, analog to digital converter, and the sensor temperature control circuits, is also described. Packaged sensors were evaluated for readout efficiency, spectral quantum efficiency, temporal noise, fixed pattern noise, and dark current. Eight sensors along with two tracker electronics boards were completed, evaluated, and delivered

    Microarray analysis of spring barley cultivars displaying differing sensitivity to physiological leaf spot (PLS)

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    peer-reviewedPhysiological leaf spot (PLS) is a disorder of spring barley (Hordeum vulgare L.), which has become more pronounced in recent years. The initial symptoms are small chlorotic/brown spots on the upper four leaves, which may develop into necrotic lesions with an irregular shape. As PLS occurs on leaves that are directly exposed to sunlight, it is thought that high light stress could be a trigger for the condition. This study concentrates on two cultivars, Cooper and Crusader, which display differential sensitivity to PLS. Biochemical measurements and enzyme assays revealed substantial difference in levels of ascorbate, type III peroxidases, and superoxide dismutase between the chosen cultivars during the 2003 growing season. A global gene expression study, using these field samples, was performed by microarray analysis. This supported the biochemical findings and highlighted additional sets of genes differentially expressed between the cultivars. Transcripts of particular interest, which appeared, included calcium signalling genes, cold-responsive genes and those involved in the assembly of Photosystem I. We conclude that susceptibility to PLS is related to levels of expression of genes with a role in countering the effects of oxidative stress.Teagasc Walsh Fellowship Programm

    One Foundation's Experience with Primary and Integrated Care Grantmaking: Lessons on Leverage and Policy Change

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    Significant changes in health care practice usually require changes in compensation practice -- and may also require changes in licensing (of facilities and/or professions), certification and professional training. This is important work that requires a long-term commitment. And it may give rise to push-back from various sources invested in the current state of affairs:* Professionals, not wanting others to be licensed to perform similar services at lower reimbursement rates* Payers, not wanting to open a door to new categories of reimbursable services* Training institutions reluctant to alter curriculum, until it is clear that a new approach has staying powerFoundations are in a powerful position to speak out for change, as we "don't have a dog in the fight." That neutrality can be our strength, particularly as we become known for speaking clearly and from a basis in factual information and evidence-based approaches

    Maclisp extensions

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    A common subset of selected facilities available in Maclisp and its derivatives (PDP-10 and Multics Maclisp, Lisp Machine Lisp (Zetalisp), and NIL) is decribed. The object is to add in writing code which can run compatibly in more than one of these environments
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