4,766 research outputs found
TB125: Fertilization of Eastern White Pine (Pinus strobus L.) in Maine Shows Economic Potential
Plots in seven eastern white pine sawlog stands were treated with nitrogen at rates of 0, 56, 112, and 224 kg/ha. After four years the largest increase in basal area growth, 0.31 dm2 /tree, and volume growth, 13.0 m3 /ha, occurred in plots that received 112 kg/ha. It appears that an application rate of 112 kg/ha may provide a real return of 15% or more in some stands.https://digitalcommons.library.umaine.edu/aes_techbulletin/1061/thumbnail.jp
Relative Comparison Kernel Learning with Auxiliary Kernels
In this work we consider the problem of learning a positive semidefinite
kernel matrix from relative comparisons of the form: "object A is more similar
to object B than it is to C", where comparisons are given by humans. Existing
solutions to this problem assume many comparisons are provided to learn a high
quality kernel. However, this can be considered unrealistic for many real-world
tasks since relative assessments require human input, which is often costly or
difficult to obtain. Because of this, only a limited number of these
comparisons may be provided. In this work, we explore methods for aiding the
process of learning a kernel with the help of auxiliary kernels built from more
easily extractable information regarding the relationships among objects. We
propose a new kernel learning approach in which the target kernel is defined as
a conic combination of auxiliary kernels and a kernel whose elements are
learned directly. We formulate a convex optimization to solve for this target
kernel that adds only minor overhead to methods that use no auxiliary
information. Empirical results show that in the presence of few training
relative comparisons, our method can learn kernels that generalize to more
out-of-sample comparisons than methods that do not utilize auxiliary
information, as well as similar methods that learn metrics over objects
Beam tests of the 12 MHz RFQ RIB injector for ATLAS
Beam tests of the ANL 12 MHz Radio-Frequency Quadrupole (RFQ), designed for use as the initial element of an injector system for radioactive beams into the existing ATLAS accelerators, are in progress. Recent high-voltage tests of the RFQ without beam achieved the design intervane voltage of 100 kV cw, enabling beam tests with A /q as large as 132 using beams from the ANL Physics Division 4 MV Dynamitron accelerator facility. Although the RFQ was designed for bunched beams, initial tests have been performed with unbunched beams. Experiments with stable, unbunched beams of singly-charged /sup 132/Xe and /sup 84/Kr measured the output beam energy distribution as a function of the RFQ operating voltage. The observed energies are in excellent agreement with numerical beam simulations. (5 refs)
Direct measurement of the transmission matrix of a mesoscopic conductor
We have developed an experimental approach which permits evaluation of the entire transmission matrix of a mesoscopic conductor. Results are presented from two new investigations enabled by this technique: (a) We study ballistic multiprobe conductors in the limit of weak probe coupling, and (b) we image modal features in the distribution function of electrons emerging from a quantum point contact
A Spectral Algorithm with Additive Clustering for the Recovery of Overlapping Communities in Networks
This paper presents a novel spectral algorithm with additive clustering
designed to identify overlapping communities in networks. The algorithm is
based on geometric properties of the spectrum of the expected adjacency matrix
in a random graph model that we call stochastic blockmodel with overlap (SBMO).
An adaptive version of the algorithm, that does not require the knowledge of
the number of hidden communities, is proved to be consistent under the SBMO
when the degrees in the graph are (slightly more than) logarithmic. The
algorithm is shown to perform well on simulated data and on real-world graphs
with known overlapping communities.Comment: Journal of Theoretical Computer Science (TCS), Elsevier, A Para\^itr
Mojave remote sensing field experiment
The Mojave Remote Sensing Field Experiment (MFE), conducted in June 1988, involved acquisition of Thermal Infrared Multispectral Scanner (TIMS); C, L, and P-band polarimetric radar (AIRSAR) data; and simultaneous field observations at the Pisgah and Cima volcanic fields, and Lavic and Silver Lake Playas, Mojave Desert, California. A LANDSAT Thematic Mapper (TM) scene is also included in the MFE archive. TM-based reflectance and TIMS-based emissivity surface spectra were extracted for selected surfaces. Radiative transfer procedures were used to model the atmosphere and surface simultaneously, with the constraint that the spectra must be consistent with field-based spectral observations. AIRSAR data were calibrated to backscatter cross sections using corner reflectors deployed at target sites. Analyses of MFE data focus on extraction of reflectance, emissivity, and cross section for lava flows of various ages and degradation states. Results have relevance for the evolution of volcanic plains on Venus and Mars
A Tribute to Patrick Baude
The Board of Editors dedicates Volume 86 of the Indiana Law Journal to the memory of Patrick Baude, who taught at the School of Law from August 1968 until his death in January 2011, and who served for many years as the faculty advisor for the Indiana Law Journal. As evidenced below, Professor Baude’s influence spread far beyond the bounds of his classroom walls, and his presence in the Law School’s community will be sorely missed
A Tribute to Patrick Baude
The Board of Editors dedicates Volume 86 of the Indiana Law Journal to the memory of Patrick Baude, who taught at the School of Law from August 1968 until his death in January 2011, and who served for many years as the faculty advisor for the Indiana Law Journal. As evidenced below, Professor Baude’s influence spread far beyond the bounds of his classroom walls, and his presence in the Law School’s community will be sorely missed
Quasi-Elastic Scattering in the Inclusive (He, t) Reaction
The triton energy spectra of the charge-exchange C(He,t) reaction
at 2 GeV beam energy are analyzed in the quasi-elastic nucleon knock-out
region. Considering that this region is mainly populated by the charge-exchange
of a proton in He with a neutron in the target nucleus and the final proton
going in the continuum, the cross-sections are written in the distorted-wave
impulse approximation. The t-matrix for the elementary exchange process is
constructed in the DWBA, using one pion- plus rho-exchange potential for the
spin-isospin nucleon- nucleon potential. This t-matrix reproduces the
experimental data on the elementary pn np process. The calculated
cross-sections for the C(He,t) reaction at to triton
emission angle are compared with the corresponding experimental data, and are
found in reasonable overall accord.Comment: 19 pages, latex, 11 postscript figures available at
[email protected], submitted to Phy.Rev.
Experimental measurement of scattering coefficients in mesoscopic conductors
We describe a general experimental approach yielding the entire transmission matrix of a multiprobe mesoscopic conductor. Results are presented for several new investigations with ballistic semiconductor nanostructures enabled by this technique. We measure the transmission coefficients for an open cross junction employing a sample design which is an almost literal realization of the Landauer-BĂĽttiker model and verify that these transmission coefficients are consistent with Hall and bend resistance anomalies obtained by resistance measurements at low magnetic fields. Other investigations utilize a pinched cross junction in which two of the probes are separated from the channel by quantum point contacts. This series arrangement of point contacts allows a sensitive momentum spectroscopy of the emitted distribution. Even in the case of a single propagating mode, through the constrictions we observe modal features in the outgoing distribution. This indicates that the potential is spatially nonadiabatic even though conductance quantization is observed. This pinched geometry also allows the first fully characterized realization of weakly coupled probes
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