New mode switching algorithm for the JPL 70-meter antenna servo controller

The design of control mode switching algorithms and logic for JPL's 70 m antenna servo controller are described. The old control mode switching logic was reviewed and perturbation problems were identified. Design approaches for mode switching are presented and the final design is described. Simulations used to compare old and new mode switching algorithms and logic show that the new mode switching techniques will significantly reduce perturbation problems

A new linear quadratic optimal controller for the 34-meter high efficiency antenna position loop

The design of a new position loop controller for the 34-meter High Efficiency Deep Space antennas using linear quadratic (LQ) optimal control techniques is discussed. The LQ optimal control theory is reviewed, and model development and verification are discussed. Families of optimal gain vectors are generated by varying weight parameters. Performance specifications were used to select a final gain vector. Estimator dynamics were selected and the corresponding gain vectors were computed. Final estimator selection was based on position, commanded rate, and estimator error responses

Occupational Therapy Intervention for Patients with Spinal Cord Injury

Spinal cord injuries are complex and debilitating, affecting every aspect of a patient\u27s life. This causes a general reduction in personal independence and social participation (Pillastrini et al., 2008). In order to provide effective and appropriate care, the interdisciplinary team must have extensive knowledge of the diagnosis and potential problems that the spinal cord patient may encounter. The purpose of this study was to identify successful interventions for an effective occupational therapy approach and to develop an education manual for use in the rehabilitation setting in order for entry-level therapists to develop competency. Based on information found in the literature review, previous continuing educational courses, and expertise of the author, a training/educational manual was developed. This resource addresses major areas of spinal cord care commonly treated by occupational therapy in a rehabilitation setting. The manual consists of major areas of spinal cord care, with each topic divided into applicable areas of treatment. Each section contains an overview of the topic, objectives for learning, precautions and contraindications, applicable treatment and possible use of adaptive equipment. This educational resource will be presented to the spinal cord development team for approval and suggestions and then to the occupational therapy team for implementation. Continued training and education for staff will provide a true collaborative effort for inpatient care and potentially increase functional independence of the patient at time of discharge (Pillastrini et al., 2008)

The biochemistry of RNA metabolism studied in situ

In vitro assays have contributed important insights into the mechanisms of RNA metabolism in cells. A growing collection of microscopy techniques is allowing the measurement of macromolecular binding and complex formation in the context of a real cell. We will first discuss two of the more established techniques. Fluorescence resonance energy transfer (FRET) identifies binding partners, pairs of molecules residing in the same macromolecular complexes. The complimentary technique of fluorescence recovery after photobleaching (FRAP) measures the rates of binding and unbinding of those molecules in their complexes. A newer technique--in vitro FRAP--assesses the regulation of binding and complex formation by co-factors in the nucleus

Impact of Farmland Preservation Programs on the Rate of Urban Development

Due to high losses of agricultural land in urbanizing areas over the past several years, state and local governments have adopted zoning regulations, right-to-farm ordinances, preferential property tax programs, and other means to protect agricultural land resources. Critics of the farmland preservation efforts note that these programs may only delay the ultimate conversion of farmland to urban uses and may simply shift urban development to neighboring areas (positive spillover effects). An alternative means of permanently protecting farmland is provided by purchase of development rights (PDR) programs, which enroll acreage from landowners who voluntarily sell the development rights to their farmland. Although ownership and all other property rights are retained by the owner, the option to develop the land for urban uses is removed from the current and all subsequent landowners. The purpose of this paper is to develop an empirical model of the impact of PDR programs on urban land development rates. To estimate the empirical model, we form a dependent variable based on county level rates of urban development from the USDA National Resources Inventory (NRI) data base for nine states in the Northeast US that have adopted farmland protection measures during the sample period (1982-1997). The set of explanatory variables include dummy variables for the existence of an active PDR program in the county and active PDR programs in adjacent counties plus measures of demographics, farm returns, population growth, income, and site-specific factors gathered from several sources (e.g., Census of Agriculture, Census of Population, and USDA). The model is estimated using the ordinary least squares technique. Two key policy-relevant hypotheses: (1) PDR programs did not reduce the rate of urban development and (2) PDR programs did not induce positive spillover effects on neighboring counties. The test results suggest that PDRs may have had important more significant impact in the earlier years and did not cause positive spillover effects.Land Economics/Use,

Experimental observations of a nuclear matrix

Nuclei are intricately structured, and nuclear metabolism has an elaborate spatial organization. The architecture of the nucleus includes two overlapping and nucleic-acid-containing structures - chromatin and a nuclear matrix. The nuclear matrix is observed by microscopy in live, fixed and extracted cells. Its ultrastructure and composition show it to be, in large part, the ribonucleoprotein (RNP) network first seen in unfractionated cells more than 30 years ago. At that time, the discovery of this RNP structure explained surprising observations that RNA, packaged in proteins, is attached to an intranuclear, non-chromatin structure. Periodic and specific attachments of chromatin fibers to the nuclear matrix create the chromatin loop domains that can be directly observed by microscopy or inferred from biochemical experiments. The ultrastructure of the nuclear matrix is well characterized and consists of a nuclear lamina and an internal nuclear network of subassemblies linked together by highly structured fibers. These complex fibers are built on an underlying scaffolding of branched 10-nm filaments that connect to the nuclear lamina. The structural proteins of the nuclear lamina have been well characterized, but the structural biochemistry of the internal nuclear matrix has received less attention. Many internal matrix proteins have been identified, but far less is known about how these proteins assemble to make the fibers, filaments and other assemblies of the internal nuclear matrix. Correcting this imbalance will require the combined application of biochemistry and electron microscopy. The central problem in trying to define nuclear matrix structure is to identify the proteins that assemble into the 10-nm filaments upon which the interior architecture of the nucleus is constructed. Only by achieving a biochemical characterization of the nuclear matrix will we advance beyond simple microscopic observations of structure to a better understanding of nuclear matrix function, regulation and post-mitotic assembly

An Empirical Examination of Real Options and the Timing of Land Conversions

Many studies have examined the effects of land use regulations on land prices and urban spatial form. Increasingly, jurisdictions have adopted incentive based mechanisms, such as purchase of development rights (PDR) programs, to manage the pace and pattern of urban growth and the conversion of agricultural land. PDR programs provide a third option to landowners in urbanizing areas: in addition to deciding whether to develop or not, landowners can decide whether to preserve their land. To our knowledge no studies have explored how the existence of an option to participate in a PDR program affects landowners' development decisions. This research provides empirical evidence of a previously untested prediction of real options theory: that additional options increase the value of waiting to make irreversible decisions. Our paper considers how an additional land use alternative, preservation, conveys a different type of option value and how that option affects the optimal conversion time. We estimate a hazard model and find significant evidence that the option to enter an easement decreases the hazard rate of development by about 40%. The results suggest that PDR programs can provide additional open space and amenity values beyond what is provided on preserved parcels, by delaying development (by at least a few years) of parcels that are not actually preserved.agricultural preservation programs, real options, land conversion, Land Economics/Use,

Exploring the Problem-Finding and Problem-Solving Approach for Designing Organizations

An emerging problem-finding and problem-solving approach suggests that management's discovering problems to solve, opportunities to seize, and challenges to respond to, are vital to organizations. This paper explores the extent to which the problem-finding and problem-solving approach can provide a foundation for joining the capabilities, dynamic capabilities, and governance perspectives as a way to help scholars and practitioners to coherently design organizations from the perspective of design science. The problem-finding and problem-solving approach offers a unit of analysis and a set of behavioral assumptions that enable us to address open questions within the extant literature and to propose new questions in management research.

Alien Registration- Nickerson, Bertha A. (Phippsburg, Sagadahoc County)

https://digitalmaine.com/alien_docs/9715/thumbnail.jp