2,111 research outputs found
Placer mining in Alaska II
During July, August and September, 1979, a team from the Mineral Industry Research Laboratory visited a number of placer mining districts that could be reached by automobile, hence at a reasonable cost for transportation. These districts yielded varying amounts of information that will be of value to the industry. The district visited were: 1. Fairbanks, 2. Circle (Birch Creak), 3. Livengood (Tolovana), 4. Manley Hot Springs, 5. Fortymile, 6. Klondike, 7. Kantishna, 8. Yentna.University of Alaska Mining and Mineral Resources Research Institute.Placer mining in Alaska II -- Selected references -- List of figures
Non-perturbative QEG Corrections to the Yang-Mills Beta Function
We discuss the non-perturbative renormalization group evolution of the gauge
coupling constant by using a truncated form of the functional flow equation for
the effective average action of the Yang-Mills-gravity system. Our result is
consistent with the conjecture that Quantum Einstein Gravity (QEG) is
asymptotically safe and has a vanishing gauge coupling constant at the
non-trivial fixed point.Comment: To appear in the proceedings of CORFU 200
Down-regulation of Groundnut Rosette Virus Replication by a Variant Satellite RNA
AbstractSymptom production in groundnut plants infected with groundnut rosette virus (GRV) depends on the presence of satellite RNA (sat-RNA) in the GRV culture, and sat-RNA variants that induce only mild symptoms are known. One such variant drastically diminished the replication of GRV genomic RNA in infectedNicotiana benthamianaplants. This down-regulating ability did not involve either of the two open reading frames in the sat-RNA but was controlled by a region near its 5β² end, which is required for sat-RNA replication. WhenN. benthamianaplants were inoculated with GRV and the mild satellite and challenged by inoculation with a GRV isolate (YB) containing a sat-RNA that induces yellow blotch symptoms, no symptoms appeared and little GRV genomic RNA or sat-RNA was detected in the plants, provided the two inoculations were no more than 2 days apart. A GRV isolate containing a sat-RNA that neither induces symptoms inN. benthamiananor affects genomic RNA accumulation also provided protection against yellow blotch symptom production if inoculated before or up to 2 days after isolate YB. However, in this case protection was incomplete and both GRV RNA and sat-RNA accumulated to normal levels. It is suggested that sequences from the mild sat-RNA may provide a novel source of resistance against rosette disease
A review of reported associations between Trichodorus and Paratrichodorus species (Nematoda : Trichodoridae) and tobraviruses with a description of laboratory methods for examining virus transmission by trichodorids
A Prescribed Wake Model for Horizontal Axis Wind Turbine Incorporating Yaw and Dynamic Inflow. G.U. Aero Report 9543
The following report summarises a three year research programme in the Department of Aerospace Engineering, University of Glasgow to develop a comprehensive prescribed wake aerodynamic model for horizontal axis wind turbines (HAWTs) capable of considering yawed and yawing flow. The original motivation for the work lay in the extensive and successful use of similar methodologies for vertical axis wind turbines and in the helicopter field. It was considered that the developed scheme would be suitable for design applications; running in minutes rather than hours. The approach used was similar to that of Coton et al.(1994) for vertical axis wind turbine applications where the blade was represented as a lifting line and a lattice of shed and trailing vortex filaments comprised the wake. The spatial and temporal development of the wake was pre-assigned using prescription functions developed in the current study and the induced flow at the blades was calculated by application of the Biot-Savart equation. Initially, the model was validated against free wake and field data for steady axial flow but was then extended to consider yawed flow. As a final stage, the unsteady aerofoil performance scheme of Lieshman and Beddoes (1989) was incorporated to account for the dynamic changes in blade loading around the azimuth in yawed flow. The resulting model has been compared to wind tunnel test data and field data supplied by NREL from the combined experiment. The work has resulted in a comprehensive aerodynamic model which is currently the focus of a follow-on EPSRC study (GR/K14995) which will extend its capabilities further
The replacement histone H2A.Z in a hyperacetylated form is a feature of active genes in the chicken
The replacement histone H2A.Z is variously reported
as being linked to gene expression and preventing the
spread of heterochromatin in yeast, or concentrated
at heterochromatin in mammals. To resolve this
apparent dichotomy, affinity-purified antibodies
against the N-terminal region of H2A.Z, in both a triacetylatedandnon-
acetylatedstate, areusedin native
chromatin immmuno-precipitation experiments with
mononucleosomes from three chicken cell types. The
hyperacetylated species concentrates at the 50 end of
active genes, both tissue specific and housekeeping
but is absent from inactive genes, while the
unacetylated form is absent from both active and
inactive genes. A concentration of H2A.Z is also
found at insulators under circumstances implying a
link to barrier activity but not to enhancer blocking.
Although acetylated H2A.Z is widespread throughout
the interphase genome, at mitosis its acetylation is
erased, the unmodified form remaining. Thus,
although H2A.Z may operate as an epigenetic marker
for active genes, its N-terminal acetylation does not
The replacement histone H2A.Z in a hyperacetylated form is a feature of active genes in the chicken
The replacement histone H2A.Z is variously reported
as being linked to gene expression and preventing the
spread of heterochromatin in yeast, or concentrated
at heterochromatin in mammals. To resolve this
apparent dichotomy, affinity-purified antibodies
against the N-terminal region of H2A.Z, in both a triacetylatedandnon-
acetylatedstate, areusedin native
chromatin immmuno-precipitation experiments with
mononucleosomes from three chicken cell types. The
hyperacetylated species concentrates at the 50 end of
active genes, both tissue specific and housekeeping
but is absent from inactive genes, while the
unacetylated form is absent from both active and
inactive genes. A concentration of H2A.Z is also
found at insulators under circumstances implying a
link to barrier activity but not to enhancer blocking.
Although acetylated H2A.Z is widespread throughout
the interphase genome, at mitosis its acetylation is
erased, the unmodified form remaining. Thus,
although H2A.Z may operate as an epigenetic marker
for active genes, its N-terminal acetylation does not
What makes theological education "theological"? a South African story on the -integrity of theological education
David Tracy claims that the contemporary emergence of a sociological
imagination is as crucial for theological self-consciousness as the earlier
rise of historical consciousness among theologians. The authors are of the
opinion that the rapid and fundamental social changes in South African
society over the past few years have accelerated this "emergence of a
sociological imagination" amongst South African theologians. In three
sections, they point to three clusters of questions that have therefore
become increasingly important, namely questions related to the growing
awareness of the crucial role of social location or context, questions
arising from a growing acknowledgement of public responsibility, and
questions concerning the integrity of theological education, i.e. the question
on what makes theological education "theological".Continued 2001 as 'Verbum et Ecclesia'Spine cut of Journal binding and pages scanned on flatbed EPSON Expression 10000 XL; 400dpi; text/lineart - black and white - stored to Tiff Derivation: Abbyy Fine Reader v.9 work with PNG-format (black and white); Photoshop CS3; Adobe Acrobat v.9 Web display format PDFhttp://explore.up.ac.za/record=b102527
Reductive atmospheric acid leaching of lateritic smectite/nontronite ores in H2SO4/Cu(II)/SO2 solutions
Despite the success of reductive atmospheric acid leaching (RAAL) of limonitic nickel laterite ores in recent studies limited attempt has been made to apply this method to smectite/nontronite ores of different mineralogies. A comparative study of four smectite/nontronite ores in this study showed that the use of 700 kg H2SO4/ton dry ore leaches only 74-86% Ni, 37-76% Co, 47-58% Fe and 24-66% Mn at 90 Β°C from slurries of 20-35% (w/w) pulp density even after 10 h, depending upon the mineralogy. These values increased to 90-97% Ni, 94-97% Co, 92-98% Mn and 72-85% Fe in the presence of Cu(II)/SO2. The first order dependence of initial fraction of iron, aluminium and nickel leached from a typical smectite ore in the first 0.5 h on the initial acid concentration provides evidence for the involvement of hydrogen ions in the surface reaction. Low activation energy of 10 kJ/mol based on the fraction of nickel leached in the first 0.5 h indicates a diffusion controlled reaction. This is supported by the applicability of a shrinking core kinetic model for metal dissolution over the first 2 h, with different apparent rate constants (kap) depending upon the iron oxide content, mineralogy and porosity. A log-log plot of kap for ores with high iron content as a function of acid concentration agrees reasonably well with the correlation already established for the leaching of nickel from limonitic laterite and manganese nodules. Thus, initial fast leaching can be related to the higher porosity and a rate controlling step which involves the diffusion of H+ through a thickening solid layer. The slow leaching at latter stages is a result of low remnant acid, thickening solid layer and changes in mineral composition
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