2,568 research outputs found
Movement of Population from the Smoky Mountains Area
Introductory: The movement of those formerly residing in the territory within the designated boundaries in Tennessee of the Great Smoky Mountain National Park, was practically completed at the time of this survey made during the early months of 1934. The assistance of the Tennessee State Park and Forestry Commission is gratefully acknowledged and the valued field work of Luther Bohannon, M. R. Brasher, James E. Carson, B. H. Kinser, and S. B. Puckette. The names of the former owners of lands, acres sold and amount received therefore was furnished through the courtesy of the Tennessee Park and Forestry Commission. With this information and the assistance of maps showing the location of the former owners, the field men visited the territories assigned them from those still remaining in the section or from those having personal knowledge of the former residence procured the following information viz: Number in the family, ages, length of time living in the neighborhood, ancestry, distance from church, store, schools, doctor, and neighbors, means of travel, character of lands and soil, portion under cultivation, days employed away from home, religious life, school opportunities, contentment, owners of automobile, radio, phonograph, acres of lands sold and amount received therefor, and influence in their removal. Other general or special information was also reported
1,3,4,6-Tetramethyl-1,4-dihydro-1,2,4,5-tetrazine, C_6H_(12)N_4
M_r =140∙19, monoclinic, P2_1/n, a = 10∙612(3), b=6∙820(1), c= 10∙975 (2) Å, β=95∙31(2)°, V=790.9(5) Å^3, Z=4, D_m=1.13(5) (flotation), D_x = 1∙177 g cm^(-3), Mo Kα, λ = 0.71073 Å, μ= 0.848 cm^(-1), F(000) = 304, T= 295 K, R = 0∙077 for 704 observed reflections. This potentially antiaromatic or homoaromatic ring system has a flattened boat conformation with both N-methyls in equatorial positions. Bond angles and distances (excluding H's) predicted to be symmetry equivalent exhibit variations of 0.002-0.014 Å and 0.0-2.0°. Substantial delocalization of the electron lone pairs of N(1) and N(4) is found
Mountain trail formation and the active walker model
We extend the active walker model to address the formation of paths on
gradients, which have been observed to have a zigzag form. Our extension
includes a new rule which prohibits direct descent or ascent on steep inclines,
simulating aversion to falling. Further augmentation of the model stops walkers
from changing direction very rapidly as that would likely lead to a fall. The
extended model predicts paths with qualitatively similar forms to the observed
trails, but only if the terms suppressing sudden direction changes are
included. The need to include terms into the model that stop rapid direction
change when simulating mountain trails indicates that a similar rule should
also be included in the standard active walker model.Comment: Introduction improved. Analysis of discretization errors added.
Calculations from alternative scheme include
Recoiling Black Holes in Quasars
Recent simulations of merging black holes with spin give recoil velocities
from gravitational radiation up to several thousand km/s. A recoiling
supermassive black hole can retain the inner part of its accretion disk,
providing fuel for a continuing QSO phase lasting millions of years as the hole
moves away from the galactic nucleus. One possible observational manifestation
of a recoiling accretion disk is in QSO emission lines shifted in velocity from
the host galaxy. We have examined QSOs from the Sloan Digital Sky Survey with
broad emission lines substantially shifted relative to the narrow lines. We
find no convincing evidence for recoiling black holes carrying accretion disks.
We place an upper limit on the incidence of recoiling black holes in QSOs of 4%
for kicks greater than 500 km/s and 0.35% for kicks greater than 1000 km/s
line-of-sight velocity.Comment: 4 pages, 4 figures, uses emulateapj, Submitted to ApJ Letter
A Case for Human Values in Software Engineering
This article argues that human values – such as responsibility, transparency, creativity, and equality – are heavily under-represented in software engineering methods. Based on experiences with real-world projects with not-for-profits, we explore how human values can be integrated into existing participatory agile practices. We propose new ways of considering human values in software practice, including: the use of the Schwartz taxonomy of human values and values portraits to contextualise values definitions; the use of values as a way to capture the rationale for requirements to ensure a culture of values throughout the software lifecycle; and a simple adaptation of agile methods to include a role for a ‘critical friend’ who can champion values during decision making
Implementing generalized deep-copy in MPI
In this paper we introduce a framework for implementing deep copy on top of MPI. The process is initiated by passing just the root object of the dynamic data structure. Our framework takes care of all pointer traversal, communication, copying and reconstruction on receiving nodes. The benefit of our approach is that MPI users can deep copy complex dynamic data structures without the need to write bespoke communication or serialize / deserialize methods for each object. These methods can present a challenging implementation problem that can quickly become unwieldy to maintain when working with complex structured data. This paper demonstrates our generic implementation, which encapsulates both approaches. We analyze the approach with a variety of structures (trees, graphs (including complete graphs) and rings) and demonstrate that it performs comparably to hand written implementations, using a vastly simplified programming interface. We make the source code available completely as a convenient header file
Computer model calibration with large non-stationary spatial outputs: application to the calibration of a climate model
Bayesian calibration of computer models tunes unknown input parameters by
comparing outputs with observations. For model outputs that are distributed
over space, this becomes computationally expensive because of the output size.
To overcome this challenge, we employ a basis representation of the model
outputs and observations: we match these decompositions to carry out the
calibration efficiently. In the second step, we incorporate the non-stationary
behaviour, in terms of spatial variations of both variance and correlations, in
the calibration. We insert two integrated nested Laplace
approximation-stochastic partial differential equation parameters into the
calibration. A synthetic example and a climate model illustration highlight the
benefits of our approach
Thin Animals
Lattice animals provide a discretized model for the theta transition
displayed by branched polymers in solvent. Exact graph enumeration studies have
given some indications that the phase diagram of such lattice animals may
contain two collapsed phases as well as an extended phase. This has not been
confirmed by studies using other means. We use the exact correspondence between
the q --> 1 limit of an extended Potts model and lattice animals to investigate
the phase diagram of lattice animals on phi-cubed random graphs of arbitrary
topology (``thin'' random graphs). We find that only a two phase structure
exists -- there is no sign of a second collapsed phase.
The random graph model is solved in the thermodynamic limit by saddle point
methods. We observe that the ratio of these saddle point equations give
precisely the fixed points of the recursion relations that appear in the
solution of the model on the Bethe lattice by Henkel and Seno. This explains
the equality of non-universal quantities such as the critical lines for the
Bethe lattice and random graph ensembles.Comment: Latex, 10 pages plus 6 ps/eps figure
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