1,013 research outputs found
Large Area Crop Inventory Experiment (LACIE). Second-generation sampling strategy evaluation report
The author has identified the following significant results. The stratification procedure in the new sampling strategy for LACIE included: (1) correlation test results indicating that an agrophysical stratum may be homogeneous with respect to agricultural density, but not with respect to wheat density; and (2) agrophysical unit homogeneity test results indicating that with respect to agricultural density many agrophysical units are not homogeneous, but removal of one or more refined strata from any such current agrophysical unit can make the strata homogeneous. The apportioning procedure results indicated that the current procedure is not performing well and that the apportioned estimates of refined strata wheat area are often unreliable
Large Area Crop Inventory Experiment (LACIE). Intensive test site assessment report
There are no author-identified significant results in this report
Fatigue Investigation of Full-scale Transport-airplane Wings : Summary of Constant-amplitude Tests Through 1953
Entropy of Extremal Black Holes in Two Dimensions
Entropy for two dimensional extremal black holes is computed explicitly in a
finite-space formulation of the black hole thermodynamics and is shown to be
zero {\it locally}. Our results are in conformity with the recent one by
Hawking et al in four dimensions.Comment: 11 page
Infinite Lorentz boost along the M-theory circle and non-asymptotically flat solutions in supergravities
Certain non-asymptotically flat but supersymmetric classical solution of the
type IIA supergravity can be interpreted as the infinitely-boosted version of
the D-particle solution along the M-theory circle. By a chain of T-dual
transformations, this analysis also applies to yield non-asymptotically flat
solutions from the asymptotically flat and (non)-extremal solutions with
intersecting D-strings and D five-branes of the type IIB supergravity
compactified on a five-torus. Under S-duality, the non-asymptotically flat
solutions in this context can in particular be used to describe the
(1+1)-dimensional CGHS type black holes via spontaneous compactifications.Comment: 14 pages, Revte
Black Holes with a Massive Dilaton
The modifications of dilaton black holes which result when the dilaton
acquires a mass are investigated. We derive some general constraints on the
number of horizons of the black hole and argue that if the product of the black
hole charge and the dilaton mass satisfies then the black
hole has only one horizon. We also argue that for there may exist
solutions with three horizons and we discuss the causal structure of such
solutions. We also investigate the possible structures of extremal solutions
and the related problem of two-dimensional dilaton gravity with a massive
dilaton.Comment: 36 pages with 5 figures (as uuencoded compressed tar file) (revised
version has one major change in bound on mass for extremal solution and minor
typos fixed), harvma
Instability of a two-dimensional extremal black hole
We consider the perturbation of tachyon about the extremal ground state of a
two-dimensional (2D) electrically charged black hole. It is found that the
presenting potential to on-coming tachyonic wave takes a double-humped barrier
well. This allows an exponentially growing mode with respect to time. This
extremal ground state is classically unstable. We conclude that the 2D extremal
electrically charged black hole cannot be a candidate for the stable endpoint
of the Hawking evaporation.Comment: 9 pages 2 figures, RevTeX, to be published in Phys. Rev D, to obtain
gifures contact Author ([email protected]
Flat World of Dilatonic Domain Walls
We study dilatonic domain walls specific to superstring theory.
Along with the matter fields and metric the dilaton also changes its value in
the wall background. We found supersymmetric (extreme) solutions which in
general interpolate between isolated superstring vacua with non-equal value of
the matter potential; they correspond to the static, planar domain walls with
{\it flat} metric in the string (sigma model) frame.
We point out similarities between the space-time of dilatonic walls and that
of charged dilatonic black holes. We also comment on non-extreme solutions
corresponding to expanding bubbles.Comment: 11 pgs (+2 figures available upon request), UPR-560-
Black Hole Remnants and the Information Puzzle
Magnetically charged dilatonic black holes have a perturbatively infinite
ground state degeneracy associated with an infinite volume throat region of the
geometry. A simple argument based on causality is given that these states do
not have a description as ordinary massive particles in a low-energy effective
field theory. Pair production of magnetic black holes in a weak magnetic field
is estimated in a weakly-coupled semiclassical expansion about an instanton and
found to be finite, despite the infinite degeneracy of states. This suggests
that these states may store the information apparently lost in black hole
scattering processes.Comment: 16 pages, revision has 5 figures uuencode
Predicting ambulatory energy expenditure in lower limb amputees using multi-sensor methods
PurposeTo assess the validity of a derived algorithm, combining tri-axial accelerometry and heart rate (HR) data, compared to a research-grade multi-sensor physical activity device, for the estimation of ambulatory physical activity energy expenditure (PAEE) in individuals with traumatic lower-limb amputation.MethodsTwenty-eight participants [unilateral (n = 9), bilateral (n = 10) with lower-limb amputations, and non-injured controls (n = 9)] completed eight activities; rest, ambulating at 5 progressive treadmill velocities (0.48, 0.67, 0.89, 1.12, 1.34m.s-1) and 2 gradients (3 and 5%) at 0.89m.s-1. During each task, expired gases were collected for the determination of and subsequent calculation of PAEE. An Actigraph GT3X+ accelerometer was worn on the hip of the shortest residual limb and, a HR monitor and an Actiheart (AHR) device were worn on the chest. Multiple linear regressions were employed to derive population-specific PAEE estimated algorithms using Actigraph GT3X+ outputs and HR signals (GT3X+HR). Mean bias±95% Limits of Agreement (LoA) and error statistics were calculated between criterion PAEE (indirect calorimetry) and PAEE predicted using GT3X+HR and AHR.ResultsBoth measurement approaches used to predict PAEE were significantly related (Pr = 0.92, bilateral; r = 0.93, and control; r = 0.91, and AHR; unilateral; r = 0.86, bilateral; r = 0.81, and control; r = 0.67). Mean±SD percent error across all activities were 18±14%, 15±12% and 15±14% for the GT3X+HR and 45±20%, 39±23% and 34±28% in the AHR model, for unilateral, bilateral and control groups, respectively.ConclusionsStatistically derived algorithms (GT3X+HR) provide a more valid estimate of PAEE in individuals with traumatic lower-limb amputation, compared to a proprietary group calibration algorithm (AHR). Outputs from AHR displayed considerable random error when tested in a laboratory setting in individuals with lower-limb amputation.</div
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