Specification of a NAVSTAR Global Positioning System (GPS) receiver for a differential GPS ground system

One step towards the successful completion of a functional ground unit for the Differential Global Positioning System (DGPS) will be in choosing a currently available GPS receiver that will accurately measure the propagation times of the satellite signals and have the capability to be electrically interfaced with and controlled by a Digital Equipment Corporation (DEC) PDP-11/34A computer. The minimum requirements and characteristics of a NAVSTAR Global Positioning System (GPS) receiver are described. The specific technical specifications addressed include data accuracies and resolutions, receiver interface/external control, enclosure dimensions and mounting requirements, receiver operation, and environmental specifications

A Loran-C prototype navigation receiver for general aviation

Prototype equipment was developed for flight evaluation which provides enroute navigation in both latitude-longitude and rho-theta coordinates. The nonprecision approach capabilities of this equipment was evaluated. The antenna/preamplifier coupler, the RF processor, tracking loop hardware, tracking loop software, and the video output are discussed. Laboratory and flight test results are evaluated

Evaluation of dissociated and steam-reformed methanol as automotive engine fuels

Dissociated and steam reformed methanol were evaluated as automotive engine fuels. Advantages and disadvantages in using methanol in the reformed rather than liquid state were discussed. Engine dynamometer tests were conducted with a four cylinder, 2.3 liter, spark ignition automotive engine to determine performance and emission characteristics operating on simulated dissociated and steam reformed methanol (2H2 + CO and 3H2 + CO2 respectively), and liquid methanol. Results are presented for engine performance and emissions as functions of equivalence ratio, at various throttle settings and engine speeds. Operation on dissociated and steam reformed methanol was characterized by flashback (violent propagation of a flame into the intake manifold) which limited operation to lower power output than was obtainable using liquid methanol. It was concluded that: an automobile could not be operated solely on dissociated or steam reformed methanol over the entire required power range - a supplementary fuel system or power source would be necessary to attain higher powers; the use of reformed mechanol, compared to liquid methanol, may result in a small improvement in thermal efficiency in the low power range; dissociated methanol is a better fuel than steam reformed methanol for use in a spark ignition engine; and use of dissociated or steam reformed methanol may result in lower exhaust emissions compared to liquid methanol

Sporadic osteochondroma of the cervical spine

Journal ArticleOsteochondroma is the most common benign tumor of bone, but axial skeleton involvement is uncommon and usually indicates a hereditary cause such as osteochondromatosis (hereditary multiple exostosis). 1 Approximately 7% of hereditary osteochondromas occur along the vertebral column, which is double the rate of vertebral column occurrences among sporadic cases.4 We present a rare pediatric case of a large sporadic osteochondroma arising from the C-3 lamina. A previously healthy 13-year-old girl with no family history of osteochondroma noticed a posterior neck mass that continued to enlarge over the following year. On examination, the mass was readily visible and nontender to palpation. The patient denied clumsiness of the hands or feet, paresthesias, or neck pain. No motor weakness, sensory disturbance, or hyperreflexia was noted. A lateral plain radiograph demonstrated a calcified mass arising dorsally from the posterior elements of the cervical spine between C-2 and C-4 (Fig. 1). Computerized tomography (CT) scans revealed that the mass was arising from the lamina of C-3 with bone remodeling of the C-2 and C-4 laminae (Fig. 2). Magnetic resonance imaging demonstrated a large multilobulated, cystic, and irregularly enhancing mass with calcified components, measuring 5.8 3 5.5 3 8.7 cm and causing mild cord compression at C3?4 (Fig. 2). The differential diagnosis for this rapidly growing spinal bone lesion included osteochondroma, osteoblastoma, osteosarcoma, and chondrosarcoma. The patient underwent a complete resection via a posterior midline cervical incision. At surgery, the tumor appeared lobulated, well-circumscribed, firm, and calcified (Fig. 3). The tumor and the C-3 lamina were removed. The results of a pathological examination were consistent with an osteochondroma. The postoperative CT scan demonstrated a gross-total resection with stable sagittal alignment

Weather data communication and utilization

The communication of weather data to aircraft is discussed. Problems encountered because of the great quantities of data available and the limited capacity to transfer this via radio link to an aircraft are discussed. Display devices are discussed

The Interstellar Medium of IRAS 08572+3915 NW: H3+ and Warm High Velocity CO

We confirm the first detection of the molecular ion H3+ in an extragalactic object, the highly obscured ultraluminous galaxy IRAS 08572+3915 NW. We also have detected absorption lines of the fundamental band of CO in this galaxy. The CO absorption consists of a cold component close to the systemic velocity and warm, highly blueshifted and redshifted components. The warm blueshifted component is remarkably strong and broad and extends at least to -350 km/s. Some analogies can be drawn between the H3+ and cold CO in IRAS08572+3915 NW and the same species seen toward the Galactic center. The profiles of the warm CO components are not those expected from a dusty torus of the type thought to obscure active galactic nuclei. They are probably formed close to the dust continuum surface near the buried and active nucleus and are probably associated with an unusual and energetic event there.Comment: 21 pages, 4 postscript figures, accepted by Ap

Locus coeruleus to basolateral amygdala noradrenergic projections promote anxiety-like behavior

Increased tonic activity of locus coeruleus noradrenergic (LC-NE) neurons induces anxiety-like and aversive behavior. While some information is known about the afferent circuitry that endogenously drives this neural activity and behavior, the downstream receptors and anatomical projections that mediate these acute risk aversive behavioral states via the LC-NE system remain unresolved. Here we use a combination of retrograde tracing, fast-scan cyclic voltammetry, electrophysiology, and in vivo optogenetics with localized pharmacology to identify neural substrates downstream of increased tonic LC-NE activity in mice. We demonstrate that photostimulation of LC-NE fibers in the BLA evokes norepinephrine release in the basolateral amygdala (BLA), alters BLA neuronal activity, conditions aversion, and increases anxiety-like behavior. Additionally, we report that β-adrenergic receptors mediate the anxiety-like phenotype of increased NE release in the BLA. These studies begin to illustrate how the complex efferent system of the LC-NE system selectively mediates behavior through distinct receptor and projection-selective mechanisms

Selecting coastal hotspots to storm impacts at the regional scale: a Coastal Risk Assessment Framework

Managing coastal risk at the regional scale requires a prioritization of resources along the shoreline. A transparent and rigorous risk assessment should inform managers and stakeholders in their choices. This requires advances in modelling assessment (e.g., consideration of source and pathway conditions to define the probability of occurrence, nonlinear dynamics of the physical processes, better recognition of systemic impacts and non-economic losses) and open-source tools facilitating stakeholders’ engagement in the process. This paper discusses how the Coastal Risk Assessment Framework (CRAF) has been developed as part of the Resilience Increasing Strategies for Coasts Toolkit (RISC-KIT). The framework provides two levels of analysis. A coastal index approach is first recommended to narrow down the risk analysis to a reduced number of sectors which are subsequently geographically grouped into potential hotspots. For the second level of analysis an integrated modelling approach improves the regional risk assessment of the identified hotspots by increasing the spatial resolution of the hazard modelling by using innovative process-based multi-hazard models, by including generic vulnerability indicators in the impact assessment, and by calculating regional systemic impact indicators. A multi-criteria analysis of these indicators is performed to rank the hotspots and support the stakeholders in their selection. The CRAF has been applied and validated on ten European case studies with only small deviation to areas already recognised as high risk. The flexibility of the framework is essential to adapt the assessment to the specific region characteristics. The involvement of stakeholders is crucial not only to select the hotpots and validate the results, but also to support the collection of information and the valuation of assets at risk. As such, the CRAF permits a comprehensive and systemic risk analysis of the regional coast in order to identify and to select higher risk areas. Yet efforts still need to be amplified in the data collection process, in particular for socio-economic and environmental impacts

Modeling the Effects of Climate Variability and Climate Change on a Pastoral Farming System

A simulation model was used to investigate the pasture and animal production and gross margins of a typical all sheep permanent pasture farm in South Canterbury, New Zealand, using 60 years of current climate data, and also a climate change scenario. The model was run on a fixed management system at different stocking rates with and without destocking during feed shortages. Mean annual pasture production was 8060 kg/ha, with a coefficient of variation of 22%. Destocking enabled more stock to be carried on average, with higher, but rh.ore variable, returns. A climate change scenario of a 75% increase in CO2\u27 1.8°C rise in mean temperature, a 5% decrease in rainfall and an 8% increase in solar radiation produced 46% higher but more variable pasture yields, resulting in optimum stocking rates, costs1 returns and gross margins all being increased 25-50%