39,069 research outputs found
Experimental determination of cosmic ray charged particle intensity profiles in the atmosphere
Absolute cosmic-ray free air ionization and charged particle fluxes and dose rates throughout the atmosphere were measured on a series of balloon flights that commenced in 1968. Argon-filled ionization chambers equipped with solid-state electrometers, with different gas pressures and steel wall thicknesses, and a pair of aluminum-wall Gm counters have provided the basic data. These data are supplemented by measurements with air-filled and tissue equivalent ionization chambers and a scintillation spectrometer. Laboratory experiments together with analyses of the theoretical aspects of the detector responses to cosmic radiation indicate that these profiles can be determined to an overall accuracy of + or - 5 percent
Phase II of the ASCE Benchmark Study on SHM
The task group on structural health monitoring of the Dynamic Committee of ASCE was formed in
1999 at the 12
th
Engineering Mechanics Conference. The task group has designed a number of analytical
studies on a benchmark structure and there are plans to follow these with an experimental program. The
first phase of the analytical studies was completed in 2001. The second phase, initiated in the summer of
2001, was formulated in the light of the experience gained on phase I and focuses on increasing realism in
the simulation of the discrepancies between the actual structure and the mathematical model used in the
analysis. This paper describes the rational that lead the SHM task group to the definition of phase II and
presents the details of the cases that are being considered
Infrared Emission from Clusters in the Starforming Disk of He2-10
We have made subarcsecond-resolution images of the central 10" of the
Wolf-Rayet dwarf galaxy He 2-10 at 11.7 microns, using the Long Wavelength
Spectrometer on the Keck Telescope. The spatial distribution of the infrared
emission roughly agrees with that of the rising spectrum radio sources seen by
Kobulnicky & Johnson (1999) and confirms that those sources are compact HII
regions rather than SNR or other objects. The infrared sources are more
extended than the subarcsecond rising spectrum radio sources, although the
entire complex is still less than 5" in extent. On sizescales of 1" the
infrared and radio emission are in excellent agreement, with each source
requiring several hundred to a thousand O stars for excitation. The nebulae lie
in a flattened disk-like distribution about 240 by 100 pc and provide all of
the flux measured by IRAS for the entire galaxy in the 12 micron band; 30% of
the total IRAS flux from the galaxy emanates from one 15-30 pc source. In this
galaxy, intense star formation, probably triggered by an accretion event, is
confined to a central disk which breaks up into distinct nebulae which
presumably mark the sites of young super star clusters.Comment: Accepted for Publication in the Astronomical Journa
Coulomb Charging Effects for Finite Channel Number
We consider quantum fluctuations of the charge on a small metallic grain
caused by virtual electron tunneling to a nearby electrode. The average
electron number and the effective charging energy are determined by means of
perturbation theory in the tunneling Hamiltonian. In particular we discuss the
dependence of charging effects on the number N of tunneling channels. Earlier
results for N>>1 are found to be approached rather rapidly with increasing N.Comment: 6 pages, 5 figure
Prospective cognitions in anxiety and depression: Replication and methodological extension
The present study presents a replication and methodological extension of MacLeod, Tata, Kentish, and Jacobsen (1997) with a nonclinical sample, using future-directed imagery to assess prospective cognitions. Results showed that only anxiety (but not depression) was related to enhanced imagery for future negative events. Both anxiety and depression showed significant zero-order correlations with reduced imagery for future positive events. However, when the overlap between anxiety and depression was controlled for, only depression (but not anxiety) showed a unique association with reduced imagery for positive events. Implications of these findings for cognitive models of anxiety and depression are discussed
Application of A Distributed Nucleus Approximation In Grid Based Minimization of the Kohn-Sham Energy Functional
In the distributed nucleus approximation we represent the singular nucleus as
smeared over a smallportion of a Cartesian grid. Delocalizing the nucleus
allows us to solve the Poisson equation for theoverall electrostatic potential
using a linear scaling multigrid algorithm.This work is done in the context of
minimizing the Kohn-Sham energy functionaldirectly in real space with a
multiscale approach. The efficacy of the approximation is illustrated
bylocating the ground state density of simple one electron atoms and
moleculesand more complicated multiorbital systems.Comment: Submitted to JCP (July 1, 1995 Issue), latex, 27pages, 2figure
Joint Emotion Analysis via Multi-task Gaussian Processes
We propose a model for jointly predicting
multiple emotions in natural language sentences.
Our model is based on a low-rank
coregionalisation approach, which combines
a vector-valued Gaussian Process
with a rich parameterisation scheme. We
show that our approach is able to learn
correlations and anti-correlations between
emotions on a news headlines dataset. The
proposed model outperforms both singletask
baselines and other multi-task approaches
The Financial Value of Postsecondary Education
Earning a postsecondary degree involves paying for tuition, fees, books, supplies, and living costs. While in school students forgo full-time job earnings; and, after earning a degree, they may pay interest on student loans for many years. This study examines 115 Wisconsin degree/school combinations to identify the value remaining after paying the costs of a postsecondary degree - the Education Value that is above and beyond what they would have earned with a high school diploma. We find the best combination delivers an additional 378,466. All combinations are investments in human capital that significantly outperform the long-term average of the U.S. stock market and may be the best investment many people ever make
Livestock Auctions in South Dakota: An Economic Analysis
In the early stages of development of livestock auctions, transportation and production conditions largely limited the distance from which firms could procure livestock. As a result most auctions were too small to attain any significant degree of efficiency in operations. In recent years, the continual development and improvement in roads and truck transportation, along with the trend toward larger producers, have reduced the time and cost of transporting livestock. As a result, procurement areas for auction firms have increased. With larger supply areas, the potential volume of auction firms has increased. With this increase in volume should come greater operational efficiency and, ultimately, lower marketing charges and costs. Thus, the primary objective of this study was to examine the cost structure of the livestock auctions in South Dakota to determine if there is any relationship between cost, volume and marketing charges
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