Alien Registration- Macdonald, Keith A. (South Portland, Cumberland County)

https://digitalmaine.com/alien_docs/20092/thumbnail.jp

Study of some problems arising from spontaneous fluctuations of electricity

In this thesis we have studied a number of problems of electrical fluctuations whose common initial origin lay in the fundamental significance of "shot" and "thermal" fluctuations. First, a theoretical and historical study was presented of the space - charge reduction of fluctuations in thermionic valves leading to a unification of the concepts of shot and thermal noise therein. In particular we observed that the common origin becomes most obvious when retarding field conditions obtain; a theoretical and experimental study of the retarding field region was therefore then undertaken. This included measurements to investigate and confirm the valve characteristics in that region and experimental observation of the fluctuations under true retarding conditions. The criteria relevant to entry into the region were also examined. As a by-product of the 'experimental fluctuation measurements, work was also undertaken on photo-electric cells and an interesting field of investigation is indicated by the results obtained. Finally, detailed statistical examination was presented of fluctuation records with relevant derived theory in which satisfactory agreement was obtained; this provided also experimental confirmation of previously known theoretical results. A possible indication of discrimination was observed between noise generated by a valve working under saturation conditions and that generated by thermal agitation in a tuned circuit such that it might possibly be accounted for by a certain degree of interaction between the primary events in the latter case. We should emphasise however, particularly in view of Chapter 2, that we are convinced that all these phenomena should be classed as thermal agitation, the terms "shot noise" and "thermal noise" being employed solely as a convenient classification indicating the electrical element wherein the fundamental phenomenon is manifeste

Temperature dependent carrier lifetime studies of Mo in crystalline silicon

The capture cross sections of both electronsσn and holes σp were determined for interstitialmolybdenum in crystalline silicon over the temperature range of −110 to 150 °C. Carrier lifetimemeasurements were performed on molybdenum-contaminated silicon using a temperature controlled photoconductance instrument. Injection dependent lifetime spectroscopy was applied at each temperature to calculate σp and σn. This analysis involved a novel approach that independently determined the capture cross sections at each temperature assuming a known defect density and thermal velocity. Since the energy state is in the lower half of the bandgap, the determination of σp is unaffected by the defect energy at all temperatures, and σp is found to decrease with temperature in a fashion consistent with excitonic Auger capture. At temperatures below 0 °C, the determination of σn is also unaffected by the defect energy due to the suppression of thermal emission, and σn decreases with temperature as well. It is shown that a projection of σn to higher temperature suggests the defect has an energy of 0.375 eV above the valance band edge of silicon.D.M. likes to thank the Australian Research Council for fellowship and G.C. likes to thank “CrystalClear Integrated Project” Contract No. SES6-CT_2003-502583 funded by the European Commission

The natural resources of Carpinteria Marsh: their status and future

The purpose of this report is: 1) to document the natural resources of Carpinteria Marsh, 2) outline the uses those resources receive, 3) enumerate the problems and conflicts of use that affect those resources, and 4) recommend measures that will protect and enhance the marsh and its resources. It is intended as a guide for citizens, planners and administrators of all private and public entities interested in the status and future of the marsh. This report has been prepared under contract to and fully funded by the Office of Biological Services of the U.S. Fish and Wildlife Service. The goals and purpose of this federal office are to review the impact on fish and wildlife resources of land, mineral and water development practices, such as offshore oil and gas exploration, development and production; construction of inshore pipeline canals and refineries; power plant construction/operation and urban development. This report, and five other southern California reports, covering Agua Hedionda (San Diego County), Anaheim Bay-Huntington Harbor (Orange County), Mugu Lagoon (Ventura County), the Northern Santa Barbara County Coastal Wetlands and the Nipomo Dunes and Wetlands (San Luis Obispo County), are scheduled to be part of the Department's "Coastal Wetland Series" that includes reports on the natural resources of Upper Newport Bay (Orange County), Goleta Slough (Santa Barbara county), Bolinas Lagoon (Marin County), Elkhorn Slough (Monterey County), San Diego Bay and Los Penasquitos Lagoon (San Diego County), Morro Bay (San Luis Obispo County), Humboldt Bay and the Eel River Delta (Humboldt County), Lake Earl and the Smith River Delta (Del Norte County) and Bodega Harbor (Sonoma County). (103pp.

Productivity Growth in U.S. Agriculture

Innovation and changes in technology have been a driving force for gains in productivity growth in U.S. agriculture. USDA's Economic Research Service has developed annual indexes of agricultural inputs, outputs, and total factor productivity (TFP) for 1948 through 2004. American agriculture relies almost entirely on productivity growth to raise output. By lowering the cost of agricultural commodities, productivity growth benefits not only farmers but also food manufacturers and consumers.Agriculture, productivity, productivity growth, total factor productivity, TFP, labor, farm economy, prices, agricultural research, agricultural output, technology, ERS, USDA, Production Economics, Productivity Analysis,

Three-point density correlation functions in the fractional quantum Hall regime

In this paper we consider the three-particle density correlation function for a fractional quantum Hall liquid. The study of this object is motivated by recent experimental studies of fractional quantum Hall systems using inelastic light scattering and phonon absorption techniques. Symmetry properties of the correlation function are noted. An exact sum-rule is derived which this quantity must obey. This sum-rule is used to assess the convolution approximation that has been used to estimate the matrix elements for such experiments. PACS Numbers: 73.40.Hm, 73.20.Mf, 72.10.DiComment: 12 pages + 1 (PS) figur

Hyperglycaemia does not increase perfusion deficits after focal cerebral ischaemia in male Wistar rats

Background: Hyperglycaemia is associated with a worse outcome in acute ischaemic stroke patients; yet the pathophysiological mechanisms of hyperglycaemia-induced damage are poorly understood. We hypothesised that hyperglycaemia at the time of stroke onset exacerbates ischaemic brain damage by increasing the severity of the blood flow deficit. Methods: Adult, male Wistar rats were randomly assigned to receive vehicle or glucose solutions prior to permanent middle cerebral artery occlusion. Cerebral blood flow was assessed semi-quantitatively either 1 h after middle cerebral artery occlusion using 99mTc-D, L-hexamethylpropyleneamine oxime (99mTc-HMPAO) autoradiography or, in a separate study, using quantitative pseudo-continuous arterial spin labelling for 4 h after middle cerebral artery occlusion. Diffusion weighted imaging was performed alongside pseudo-continuous arterial spin labelling and acute lesion volumes calculated from apparent diffusion coefficient maps. Infarct volume was measured at 24 h using rapid acquisition with refocused echoes T2-weighted magnetic resonance imaging. Results: Glucose administration had no effect on the severity of ischaemia when assessed by either 99mTc-HMPAO autoradiography or pseudo-continuous arterial spin labelling perfusion imaging. In comparison to the vehicle group, apparent diffusion coefficient–derived lesion volume 2–4 h post-middle cerebral artery occlusion and infarct volume 24 h post-middle cerebral artery occlusion were significantly greater in the glucose group. Conclusions: Hyperglycaemia increased acute lesion and infarct volumes but there was no evidence that the acute blood flow deficit was exacerbated. The data reinforce the conclusion that the detrimental effects of hyperglycaemia are rapid, and that treatment of post-stroke hyperglycaemia in the acute period is essential but the mechanisms of hyperglycaemia-induced harm remain unclear

Generalized procedure to determine the dependence of steady-state photoconductance lifetime on the occupation of multiple defects

We present a procedure to determine the dependence of photoconductance lifetime on the occupation of multiple defects. The procedure requires numerical iteration, making it more cumbersome than the analytical equations available for single-defect and simplified two-defect cases, but enabling the following features: (i) it accounts for the defect concentration when calculating the equilibrium carrier concentrations, (ii) it permits recombination through any number of defects, (iii) it calculates the occupation fraction of all defects at any injection, and (iv) it promotes a good understanding of the role of defect occupation in photoconductance measurements. The utility of the numerical procedure is demonstrated on an experimental sample containing multiple defects. The dependence of the sample’s photoconductance on carrier concentration and temperature can be qualitatively described by the generalized procedure but not by either analytical model. The example also demonstrates that the influence of defect occupation on photoconductance lifetime measurements is mitigated at elevated temperatures—a conclusion of particular worth to the study of multicrystalline silicon.This work was funded by an Australian Research Council Linkage Grant between the Australian National University, SierraTherm Production Furnaces, and SunPower Corporation. D.M. is supported by an Australian Research Council fellowship

Policy and practice in an atoll territory : British rule in the Gilbert and Ellice Islands, 1892-1970.

The sixteen Gilbert and nine Ellice Islands form a chain of coral atolls and reef islands that lies between latitudes 3°30'N and 2°45'S and longitudes 172°30'E and 180° in the central Pacific Ocean. Only Butaritari, Tarawa and Abemama in the Gilberts and Nukufetau and Funafuti in the Ellice Islands offer safe lagoon anchorages for ships with a draft in excess of fifteen feet. Landing at the reef islands, for example at Nikunau and Tamana in the Gilberts or at Nanumanga and Niutao in the Ellice, can be hazardous in calm weather and is virtually impossible during westerly storms. Poor soils, composed primarily of sand and vegetal deposits, sparse and irregular rainfall, and the shallow freshwater lens associated with low coral islands (maximum altitude of about fifteen feet) all combine to place severe limitations on the range of agricultural crops that can be grown. Pandanus, breadfruit and the ubiquitous coconut are the main tree crops and a coarse taro-like plant (known as babai in the Gilberts and pulaka in the Ellice) is laboriously cultivated in pits up to eight feet in depth on all islands. A wider range of exotic crops, bananas and papaw for example,can be grown with ease in the Ellice Islands but only with difficulty on most of the Gilbert Islands. Throughout both groups, traditional systems of land tenure which have led to extensive fragmentation make effective land utilisation difficult; the problem is complicated on those atolls which consist of a string of islets spread along a reef. It is clear that, before the days of imported foodstuffs, the Gilbertese and Ellice Islanders were forced to live in a delicate balance with their environment