Noise and Equivalent Circuit of Double Injection

Measurements of the high‐frequency noise of a silicon double‐injection diode result in 〈i^2〉 = α⋅4kT(1/r)Δf with α=1.04 and in agreement with the literature. A new interpretation demands Nyquist noise with α≡1 in these devices at high frequencies. This is in accord with an equivalent circuit derived for the double‐injection process. Speculations are made on the general validity of Nyquist noise in nonlinear devices at high frequencies. In addition, generation‐recombination noise is suggested as the prime source of the low‐frequency noise

Life-Cycle impacts of Inland Northwest and Northeast/North central forest resources

Determining the life-cycle inventory (LCI) and impact of forest harvest, regeneration, and growth is necessary in conducting a life-cycle assessment of wood products. This publication provides quantitative assessments of the economic and environmental impacts of forest management activities covering portions of the Inland Northwest (INW), including Montana, Idaho, and eastern Washington, and of the Northeastern and North Central (NE/NC) forests from Minnesota to Maine and south as far as Missouri, West Virginia, and Pennsylvania. The management scenarios provide the inputs needed to develop an LCI on all the inputs and outputs for wood products as impacted by forest treatments and the harvesting of logs in the region. Productive timberlands were grouped according to forest type, productivity, management intensity, and ownership into three broad forest types in the west: cold, dry, and moist; and four in the east: spruce/fir, northern hardwoods, oak/hickory, and aspen/birch. Spruce/fir represented the feedstock to softwood lumber and a composite of northern hardwoods and oak/hickory the feedstock to hardwood lumber. Simulations used the US Forest Service Forest Vegetation Simulator to estimate standing and harvested biomass and log volumes passed on as resources to the manufacturing segments for lumber, plywood, or oriented strandboard. The combinations of ownership, management intensity, and forest type were stratified and averaged to produce a single estimate of yield and the corresponding harvesting impacts. Both historic harvest rates and increased management intensity scenarios were simulated for each region. In the INW, the shift to the higher intensity scenario increased the average production of merchantable volume at harvest to 249 - 399 m3/ha when averaged across the forested land in each ownership class. For the NE/NC region, the production of merchantable volume averaged 263 m3/ha for softwood and 328 m3/ha for hardwood forests with an insignificant volume response from shifting land into more intensive management. Average growth varied widely for INW forest categories from a low on federal land for the base case of 0.7 - 6.7 m3/haha·yr for moist state and private land under the intensive management alternative. Current condition estimates of softwood log and bark carbon exported for mill processing in the INW and NE/NC regions were 751 and 988 kg/ha·yr, respectively

Investigating situated cultural practices through cross-sectoral digital collaborations: policies, processes, insights

The (Belfast) Good Friday Agreement represents a major milestone in Northern Ireland's recent political history, with complex conditions allowing for formation of a ‘cross-community’ system of government enabling power sharing between parties representing Protestant/loyalist and Catholic/nationalist constituencies. This article examines the apparent flourishing of community-focused digital practices over the subsequent ‘post-conflict’ decade, galvanised by Northern Irish and EU policy initiatives armed with consolidating the peace process. Numerous digital heritage and storytelling projects have been catalysed within programmes aiming to foster social processes, community cohesion and cross-community exchange. The article outlines two projects—‘digital memory boxes’ and ‘interactive galleon’—developed during 2007–2008 within practice-led PhD enquiry conducted in collaboration with the Nerve Centre, a third-sector media education organisation. The article goes on to critically examine the processes involved in practically realising, and creatively and theoretically reconciling, community-engaged digital production in a particular socio-political context of academic-community collaboration

Evidence for Interindividual Heterogeneity in the Glucose Gradient Across the Human Red Blood Cell Membrane and Its Relationship to Hemoglobin Glycation

OBJECTIVE—To determine whether interindividual heterogeneity in the erythrocyte (red blood cell [RBC]) transmembrane glucose gradient might explain discordances between A1C and glycemic control based on measured fructosamine

Production of highly-polarized positrons using polarized electrons at MeV energies

The Polarized Electrons for Polarized Positrons experiment at the injector of the Continuous Electron Beam Accelerator Facility has demonstrated for the first time the efficient transfer of polarization from electrons to positrons produced by the polarized bremsstrahlung radiation induced by a polarized electron beam in a high-$Z$ target. Positron polarization up to 82\% have been measured for an initial electron beam momentum of 8.19~MeV/$c$, limited only by the electron beam polarization. This technique extends polarized positron capabilities from GeV to MeV electron beams, and opens access to polarized positron beam physics to a wide community.Comment: 5 pages, 4 figure

Antiferromagnetic real-space configuration probed by x-ray orbital angular momentum phase dichroism

X-ray beams with orbital angular momentum (OAM) are an up-and-coming tool for x-ray characterization techniques. Beams with OAM have an azimuthally varying phase that leads to a gradient of the light field. New material properties can be probed by utilizing the unique phase structure of an OAM beam. Here, we demonstrate a novel type of phase dichroism in resonant diffraction from an artificial antiferromagnet with a topological defect. The scattered OAM beam has circular dichroism whose sign is coupled to the phase of the beam, which reveals the real-space configuration of the antiferromagnetic ground state. Thermal cycling of the artificial antiferromagnet can change the ground state, as indicated by the changing phase dichroism. These results exemplify the potential of OAM beams to probe matter in a way that is inaccessible using typical x-ray techniques

ASL expression in ALDH1A1+ neurons in the substantia nigra metabolically contributes to neurodegenerative phenotype

Argininosuccinate lyase (ASL) is essential for the NO-dependent regulation of tyrosine hydroxylase (TH) and thus for catecholamine production. Using a conditional mouse model with loss of ASL in catecholamine neurons, we demonstrate that ASL is expressed in dopaminergic neurons in the substantia nigra pars compacta, including the ALDH1A1 + subpopulation that is pivotal for the pathogenesis of Parkinson disease (PD). Neuronal loss of ASL results in catecholamine deficiency, in accumulation and formation of tyrosine aggregates, in elevation of α-synuclein, and phenotypically in motor and cognitive deficits. NO supplementation rescues the formation of aggregates as well as the motor deficiencies. Our data point to a potential metabolic link between accumulations of tyrosine and seeding of pathological aggregates in neurons as initiators for the pathological processes involved in neurodegeneration. Hence, interventions in tyrosine metabolism via regulation of NO levels may be therapeutic beneficial for the treatment of catecholamine-related neurodegenerative disorders