386 research outputs found
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
Geochemical-geophysical investigations, Fairbanks district
Trace element distribution in a subarctic valley in the Cleary Hill area of the Fairbanks gold district has been studied.
Zinc and arsenic have been found excellent pathfinder elements for auriferous deposits. Methods of analysis for copper, lead, zinc, molybdenum, silver and arsenic as well as heavy metals are discussed. The University of Alaska method #2 has been improved, Terrain, slope, and frozen ground have little effect upon the distribution of trace elements associated with the Cleary H i l l vein. A new method for the determination of zinc using dilute acid is proposed. Analysis of geochemical data by trend surface procedures proved effective for localization of anomalies
A Cluster Method for the Ashkin--Teller Model
A cluster Monte Carlo algorithm for the Ashkin-Teller (AT) model is
constructed according to the guidelines of a general scheme for such
algorithms. Its dynamical behaviour is tested for the square lattice AT model.
We perform simulations on the line of critical points along which the exponents
vary continuously, and find that critical slowing down is significantly
reduced. We find continuous variation of the dynamical exponent along the
line, following the variation of the ratio , in a manner which
satisfies the Li-Sokal bound , that was so far
proved only for Potts models.Comment: 18 pages, Revtex, figures include
CAPABLE trial: A randomized controlled trial of nurse, occupational therapist and handyman to reduce disability among older adults: Rationale and design
AbstractBackgroundAs the population ages, it is increasingly important to test new models of care that improve life quality and decrease health costs. This paper presents the rationale and design for a randomized clinical trial of a novel interdisciplinary program to reduce disability among low income older adults based on a previous pilot trial of the same design showing strong effect.MethodsThe CAPABLE (Community Aging in Place, Advancing Better Living for Elders) trial is a randomized controlled trial in which low income older adults with self-care disability are assigned to one of two groups: an interdisciplinary team of a nurse, occupational therapist, and handyman to address both personal and environmental risk factors for disability based on participants' functional goals, or an attention control of sedentary activities of choice. Both groups receive up to 10 home visits over 4months.OutcomesThe primary outcome is decreased disability in self-care (ADL). Secondary outcomes are sustained decrease in self care disability as well as improvement in instrumental ADLS, strength, balance, walking speed, and health care utilization. Careful cost tracking and analysis using intervention data and claims data will enable direct measurement of the cost impact of the CAPABLE approach. CAPABLE has the potential to leverage current health care spending in Medicaid waivers, Accountable Care Organizations and other capitated systems to save the health care system costs as well as improving low income older adults' ability to age at home with improved life quality
Social reward among juvenile mice
Mammalian social relationships, such as mother–offspring attachments and pair bonds, can directly affect reproductive output. However, conspecifics approach one another in a comparatively broad range of contexts, so conceivably there are motivations for social congregation other than those underlying reproduction, parental care or territoriality. Here, we show that reward mediated by social contact is a fundamental aspect of juvenile mouse sociality. Employing a novel social conditioned place preference (SCPP) procedure, we demonstrate that social proximity is rewarding for juvenile mice from three inbred strains (A/J, C57BL/6J and DBA/2J), while mice from a fourth strain (BALB/cJ) are much less responsive to social contact. Importantly, this strain-dependent difference was not related to phenotypic variability in exploratory behavior or contextual learning nor influenced by the genetic background associated with maternal care or social conditioning. Furthermore, the SCPP phenotype was expressed early in development (postnatal day 25) and did not require a specific sex composition within the conditioning group. Finally, SCPP responses resulted from an interaction between two specifiable processes: one component of the interaction facilitated approach toward environments that were associated with social salience, whereas a second component mediated avoidance of environmental cues that predicted social isolation. We have thus identified a genetically prescribed process that can attribute value onto conditions predicting a general form of social contact. To our knowledge, this is the first definitive evidence to show that genetic variation can influence a form of social valuation not directly related to a reproductive behavior
Self-Averaging, Distribution of Pseudo-Critical Temperatures and Finite Size Scaling in Critical Disordered Systems
The distributions of singular thermodynamic quantities in an ensemble
of quenched random samples of linear size at the critical point are
studied by Monte Carlo in two models. Our results confirm predictions of
Aharony and Harris based on Renormalization group considerations. For an
Ashkin-Teller model with strong but irrelevant bond randomness we find that the
relative squared width, , of is weakly self averaging. , where is the specific heat exponent and is the
correlation length exponent of the pure model fixed point governing the
transition. For the site dilute Ising model on a cubic lattice, known to be
governed by a random fixed point, we find that tends to a universal
constant independent of the amount of dilution (no self averaging). However
this constant is different for canonical and grand canonical disorder. We study
the distribution of the pseudo-critical temperatures of the ensemble
defined as the temperatures of the maximum susceptibility of each sample. We
find that its variance scales as and NOT as
R_\chi\sim 70R_\chi (T_c)\chiT_c(i,l)m_i(T_c,l)T_c(i,l)(T-T_c(i,l))/T_c$. This function is found to be universal and to behave
similarly to pure systems.Comment: 31 pages, 17 figures, submitted to Phys. Rev.
Surface critical exponents at a uniaxial Lifshitz point
Using Monte Carlo techniques, the surface critical behaviour of
three-dimensional semi-infinite ANNNI models with different surface
orientations with respect to the axis of competing interactions is
investigated. Special attention is thereby paid to the surface criticality at
the bulk uniaxial Lifshitz point encountered in this model. The presented Monte
Carlo results show that the mean-field description of semi-infinite ANNNI
models is qualitatively correct. Lifshitz point surface critical exponents at
the ordinary transition are found to depend on the surface orientation. At the
special transition point, however, no clear dependency of the critical
exponents on the surface orientation is revealed. The values of the surface
critical exponents presented in this study are the first estimates available
beyond mean-field theory.Comment: 10 pages, 7 figures include
Reexamination of the long-range Potts model: a multicanonical approach
We investigate the critical behavior of the one-dimensional q-state Potts
model with long-range (LR) interaction , using a multicanonical
algorithm. The recursion scheme initially proposed by Berg is improved so as to
make it suitable for a large class of LR models with unequally spaced energy
levels. The choice of an efficient predictor and a reliable convergence
criterion is discussed. We obtain transition temperatures in the first-order
regime which are in far better agreement with mean-field predictions than in
previous Monte Carlo studies. By relying on the location of spinodal points and
resorting to scaling arguments, we determine the threshold value
separating the first- and second-order regimes to two-digit precision within
the range . We offer convincing numerical evidence supporting
$\sigma_c(q)Comment: 18 pages, 18 figure
Coastal flood risks in China through the 21st century – An application of DIVA.
China experiences frequent coastal flooding, with nearly US 67-3,308 billion damages/yr are projected without upgrade to defences. In contrast, maintaining the current protection level would reduce those numbers to 0.2-0.4 million people flooded/yr and US 8-17 billion/yr. In 2100, maintaining current protection levels, dikes costs are two orders of magnitude smaller than flood costs across all scenarios, even without accounting for indirect damages. This research improves on earlier national assessments of China by generating a wider range of projections, based on improved datasets. The information delivered in this study will help governments, policy-makers, insurance companies and local communities in China understand risks and design appropriate strategies to adapt to increasing coastal flood risk in an uncertain world
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