Optimum transportation systems to serve the mineral industry north of the Yukon basin in Alaska

In 1972 the U. S . Bureau of Mines awarded a grant (No. G 01 22096) to the Mineral Industry Research Laboratory, University of Alaska, for a research project to determine optimum transportation systems to serve the mineral industry north of the Yukon River basin in Alaska. The study was conducted during the period May 1 - November 1, 1972. The study assesses the mineral potential of the region and selects two copper deposits: a known one at Bornite, and a potential one on the upper Koyukuk River. Two possible mining sites within the extensive coal bearing region north of the Brooks Range are also selected. A computer model was developed to perform an economic analysis of technically feasible transportation modes and routes from these four sites to Alaskan ports from which minerals could be shipped to markets. Transport modes considered are highway, rail, cargo aircraft, river barge, winter haul road and air cushion vehicles (A.C.V.). The computer program calculates the present worth of tax benefits from mining and transportation and revenues based on the value of minerals at the port, as well as the auxillary benefits derived from the anticipated use of the routes by the tourist industry. Annual and fixed costs of mining and transportation of minerals are calculated, and benefit-cost ratios determined for each combination of routes and modes serving the four mineral sites. The study concludes that the best systems in terms of a high benefit-cost ratio are those utilizing a minimum of new construction of conventional highways or railroads. The optimum system as derived from this study is one linking together existing transportation systems with aircraft or A.C.V. These modes are feasible only for the shipment of a high value product, namely blister copper produced by a smelter at the mining site, Of the several alternatives considered for the shipment of coal, only a slurry pipeline to an as yet undeveloped port on the Arctic coast showed significant promise. The study recommends that: 1. More government support should be given to mineral exploration in Alaska. 2. Potential mineral industry development should be considered in transportation planning at state and federal levels. 3. Additional research pertinent to mining and processing of minerals in the North should be conducted, and the feasibility of smelting minerals within Alaska explored. 4. Alternatives for providing power to Northwestern Alaska should be investigated

SELECTION RESPONSE FOR INCREASED GRAIN YIELD IN TWO HIGH OIL MAIZE SYNTHETICS

Selection for increased oil level in maize showed the increase was associated with decrease in starch concentration, kernel weight, and grain yield. The study was conducted with the objectives: (1) to evaluate response to six cycles for increased grain yield in the high oil maize Alexho Elite (AE: 60-90 g kg-1 oil concentration) and Ultra High Oil (UHO: 100-140 g kg-1 oil concentration) using inbred tester B73; (2) to measure responses to selection for increased grain yield with changes in yield components; and (3) to determine a suitable tester. Previously the two synthetics had been selected for oil concentration. After six cycles, the six genotypes i.e. AE C0, AE C3, AE C6, UHO C0, UHO C3, and UHO C6 were testcrossed to B73, LH185, and LH202 inbreds (40 g kg-1 oil concentration) to a total of 18 testcrosses. Two field experiments were used to evaluate selection in AE and UHO testcrosses. The study showed selection using inbred tester B73 in AE and UHO was effective in increasing grain yield of AE testcrosses without changing (i.e. decreasing) oil and protein concentrations. AE testcrosses produced higher grain yield and greater selection response for grain yield than UHO testcrosses. LH185 was best for grain yield in AE and UHO testcrosses. Increase in grain yield in most of the testcrosses was associated with increases in starch concentration, kernel weight, kernel number, and grain weight

Andreev Reflection in Ferromagnet/Superconductor/Ferromagnet Double Junction Systems

We present a theory of Andreev reflection in a ferromagnet/superconductor/ferromagnet double junction system. The spin polarized quasiparticles penetrate to the superconductor in the range of penetration depth from the interface by the Andreev reflection. When the thickness of the superconductor is comparable to or smaller than the penetration depth, the spin polarized quasiparticles pass through the superconductor and therefore the electric current depends on the relative orientation of magnetizations of the ferromagnets. The dependences of the magnetoresistance on the thickness of the superconductor, temperature, the exchange field of the ferromagnets and the height of the interfacial barriers are analyzed. Our theory explains recent experimental results well.Comment: 8 pages, 9 figures, submitted to Phys. Rev.

Pressure and linear heat capacity in the superconducting state of thoriated UBe13

Even well below Tc, the heavy-fermion superconductor (U,Th)Be13 has a large linear term in its specific heat. We show that under uniaxial pressure, the linear heat capacity increases in magnitude by more than a factor of two. The change is reversible and suggests that the linear term is an intrinsic property of the material. In addition, we find no evidence of hysteresis or of latent heat in the low-temperature and low-pressure portion of the phase diagram, showing that all transitions in this region are second order.Comment: 5 pages, 4 figure

Exact time-localized solutions in Vacuum String Field Theory

We address the problem of finding star algebra projectors that exhibit localized time profiles. We use the double Wick rotation method, starting from an Euclidean (unconventional) lump solution, which is characterized by the Neumann matrix being the conventional one for the continuous spectrum, while the inverse of the conventional one for the discrete spectrum. This is still a solution of the projector equation and we show that, after inverse Wick-rotation, its time profile has the desired localized time dependence. We study it in detail in the low energy regime (field theory limit) and in the extreme high energy regime (tensionless limit) and show its similarities with the rolling tachyon solution.Comment: 27 pages, 2 figures. v2: typos corrected, ref added, comment added in last section, to appear on NP

Conductance behavior of tetraphenyl-Aza-Bodipys

We studied the electrical conductance of single-molecule junctions formed from molecular wires with four anchor groups. Three tetraphenyl-aza-BODIPYs with four or two thiomethyl anchor groups were synthesized, and their single-molecule conductance was measured using break-junction-STM. Using DFT based calculations these compounds were shown to display a combination of a high and low conductance, depending on the molecule's connectivity in the junction. A scissor correction is employed to obtain the corrected HOMO-LUMO gaps and a tight binding model (TBM) is used to highlight the role of transport through the pi system of the tetraphenyl-aza-BODIPY central unit. The three higher-conductance geometries follow the sequence 3 > 4 > 2, which demonstrates that their conductances are correlated with the number of anchors

HOPX functions as a tumour suppressor in head and neck cancer.

Head and neck squamous cell carcinoma (HNSCC) is generalized term that encompasses a diverse group of cancers that includes tumours of the oral cavity (OSCC), oropharynx (OPSCC) and nasopharynx (NPC). Genetic alterations that are common to all HNSCC types are likely to be important for squamous carcinogenesis. In this study, we have investigated the role of the homeodomain-only homeobox gene, HOPX, in the pathogenesis of HNSCC. We show that HOPX mRNA levels are reduced in OSCC and NPC cell lines and tissues and there is a general reduction of HOPX protein expression in these tumours and OPSCCs. HOPX promoter methylation was observed in a subset of HNSCCs and was associated with a worse overall survival in HPV negative tumours. RNAseq analysis of OSCC cells transfected with HOPX revealed a widespread deregulation of the transcription of genes related to epithelial homeostasis and ectopic over-expression of HOPX in OSCC and NPC cells inhibited cell proliferation, plating efficiency and migration, and enhanced sensitivity to UVA-induced apoptosis. Our results demonstrate that HOPX functions as a tumour suppressor in HNSCC and suggest a central role for HOPX in suppressing epithelial carcinogenesis

Spin-polarized transport and Andreev reflection in semiconductor/superconductor hybrid structures

We show that spin-polarized electron transmission across semiconductor/superconductor (Sm/S) hybrid structures depends sensitively on the degree of spin polarization as well as the strengths of potential and spin-flip scattering at the interface. We demonstrate that increasing the Fermi velocity mismatch in the Sm and S regions can lead to enhanced junction transparency in the presence of spin polarization. We find that the Andreev reflection amplitude at the superconducting gap energy is a robust measure of the spin polarization magnitude, being independent of the strengths of potential and spin-flip scattering and the Fermi velocity of the superconductor.Comment: 4 pages, 2 figure

Quasiclassical description of transport through superconducting contacts

We present a theoretical study of transport properties through superconducting contacts based on a new formulation of boundary conditions that mimics interfaces for the quasiclassical theory of superconductivity. These boundary conditions are based on a description of an interface in terms of a simple Hamiltonian. We show how this Hamiltonian description is incorporated into quasiclassical theory via a T-matrix equation by integrating out irrelevant energy scales right at the onset. The resulting boundary conditions reproduce results obtained by conventional quasiclassical boundary conditions, or by boundary conditions based on the scattering approach. This formalism is well suited for the analysis of magnetically active interfaces as well as for calculating time-dependent properties such as the current-voltage characteristics or as current fluctuations in junctions with arbitrary transmission and bias voltage. This approach is illustrated with the calculation of Josephson currents through a variety of superconducting junctions ranging from conventional to d-wave superconductors, and to the analysis of supercurrent through a ferromagnetic nanoparticle. The calculation of the current-voltage characteristics and of noise is applied to the case of a contact between two d-wave superconductors. In particular, we discuss the use of shot noise for the measurement of charge transferred in a multiple Andreev reflection in d-wave superconductors