Some properties of canonical correlations and variates in infinite dimensions

AbstractIn this paper the notion of functional canonical correlation as a maximum of correlations of linear functionals is explored. It is shown that the population functional canonical correlation is in general well defined, but that it is a supremum rather than a maximum, so that a pair of canonical variates may not exist in the spaces considered. Also the relation with the maximum eigenvalue of an associated pair of operators and the corresponding eigenvectors is not in general valid. When the inverses of the operators involved are regularized, however, all of the above properties are restored. Relations between the actual population quantities and their regularized versions are also established. The sample functional canonical correlations can be regularized in a similar way, and consistency is shown at a fixed level of the regularization parameter

An absolute determination of the 235U fission cross section at 964 keV

An absolute measurement of the 235U fission cross section has been carried out using a 24Na---Be photoneutron source with median neutron energy of 964 keV. A symmetric two-foil experiment was set up to measure the fission rate in a low-albedo laboratory, and variations in the source-to-foil spacing used to determine the room background. Fission fragments passing through a limited solid angle aperture were recorded from each foil by solid state tracketch techniques. The photoneutron source was calibrated after each run using the manganese bath method and the secondary national standard source NBS-II. A computed neutron source spectrum with 32 keV FWHM was derived by the Monte Carlo method and used in reducing the data to a cross section at 964 keV. The final value of 1.21 +/- 0.025 barns is absolute in that, except for small corrections, its determination was independent of any other cross section data.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22187/1/0000618.pd

WRF-CMAQ two-way coupled system with aerosol feedback: software development and preliminary results

Air quality models such as the EPA Community Multiscale Air Quality (CMAQ) require meteorological data as part of the input to drive the chemistry and transport simulation. The Meteorology-Chemistry Interface Processor (MCIP) is used to convert meteorological data into CMAQ-ready input. Key shortcoming of such one-way coupling include: excessive temporal interpolation of coarsely saved meteorological input and lack of feedback of atmospheric pollutant loading on simulated dynamics. We have developed a two-way coupled system to address these issues. A single source code principle was used to construct this two-way coupling system so that CMAQ can be consistently executed as a stand-alone model or part of the coupled system without any code changes; this approach eliminates maintenance of separate code versions for the coupled and uncoupled systems. The design also provides the flexibility to permit users: (1) to adjust the call frequency of WRF and CMAQ to balance the accuracy of the simulation versus computational intensity of the system, and (2) to execute the two-way coupling system with feedbacks to study the effect of gases and aerosols on short wave radiation and subsequent simulated dynamics. Details on the development and implementation of this two-way coupled system are provided. When the coupled system is executed without radiative feedback, computational time is virtually identical when using the Community Atmospheric Model (CAM) radiation option and a slightly increased (~8.5 %) when using the Rapid Radiative Transfer Model for GCMs (RRTMG) radiation option in the coupled system compared to the offline WRF-CMAQ system. Once the feedback mechanism is turned on, the execution time increases only slightly with CAM but increases about 60 % with RRTMG due to the use of a more detailed Mie calculation in this implementation of feedback mechanism. This two-way model with radiative feedback shows noticeably reduced bias in simulated surface shortwave radiation and 2 m temperatures as well improved correlation of simulated ambient ozone and PM<sub>2.5</sub> relative to observed values for a test case with significant tropospheric aerosol loading from California wildfires

Measurement of the Neutron Lifetime by Counting Trapped Protons in a Cold Neutron Beam

A measurement of the neutron lifetime $\tau_{n}$ performed by the absolute counting of in-beam neutrons and their decay protons has been completed. Protons confined in a quasi-Penning trap were accelerated onto a silicon detector held at a high potential and counted with nearly unit efficiency. The neutrons were counted by a device with an efficiency inversely proportional to neutron velocity, which cancels the dwell time of the neutron beam in the trap. The result is $\tau_{n} = (886.6\pm1.2{\rm [stat]}\pm3.2{\rm [sys]})$ s, which is the most precise measurement of the lifetime using an in-beam method. The systematic uncertainty is dominated by neutron counting, in particular the mass of the deposit and the $^{6}$Li({\it{n,t}}) cross section. The measurement technique and apparatus, data analysis, and investigation of systematic uncertainties are discussed in detail.Comment: 71 pages, 20 figures, 9 tables; submitted to PR

Absolute measurements of 235U and 239Pu fission cross-sections with photoneutron sources

the fission cross-sections of 235U and 239Pu for Na---Be, La---Be, Na---D and Ga---D photoneutrons have been measured absolutely. The neutron source strength was measured using a manganese bath to compare the photoneutron yield from the sources with the standard source NBS-II. Fission counts were accumulated with the source positioned symmetrically between two identical fission foils in an experiment package suspended in a low-albedo laboratory. Fission fragments passing through limited solid angle apertures were recorded on polyester track-etch films. The masses of the foil deposits were determined by microbalance weighings and confirmed by thermal neutron fission and alpha counting. After making a correction for the calculated energy distribution of the source neutrons, values of 1.471 +/- 0.029, 1.274 +/- 0.026, 1.162 +/- 0.025 and 1.195 +/- 0.026 barns were obtained for the 235U fission cross-section at the source median energies of 140, 265, 770 and 964 keV, respectively. Corresponding values of 1.469 +/- 0.045, 1.515 +/- 0.038, 1.670 +/- 0.039 and 1.643 +/- 0.038 barns were determined for 239Pu.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22757/1/0000312.pd

Ventral motor neuron alterations in rat spinal cord after chronic exercise

The observed differences in the soma and nuclear diameters reflect chronic changes specific to each exercise regimen used.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42652/1/18_2005_Article_BF01946563.pd

Ornamental plants, 1979: a summary of research

An analysis of production costs for containerized nursery products / David E. Hahn, Jerry L. Robertson, and Elton M. Smith -- Monoterpene investigations with creeping juniper cultivars (Juniperus horizontalis Moench.) / Thomas A. Fretz -- Woody flora in Hokkaido adaptable to the north central United States / Makoto Kawase -- An evaluation of microfoam on plant quality following overwintering of container-grown woody ornamentals / Christopher F. Rizzo, Elton M. Smith, and Thomas A. Fretz -- Evaluation of winter barrels as a heat source in woody ornamental winter storage structures / Christopher F. Rizzo, Elton M. Smith, and Thomas A. Fretz_ -- Effective utilization of applied fertilizer in relation to multiple flushes of growth on 'Helleri' holly / C. H. Gilliam and R. D. Wright -- Tissue nitrogen changes during a growth flush on 'Helleri' holly / C. H. Gilliam and R. D. Wright -- Controlling winter annual and perennial weeds in field-grown Cotoneaster divaricata / Elton M. Smith and Sharon A. Treaster -- Evaluation of oxadiazon for weed control in container-grown nursery stock / Thomas A. Fretz and Wendy J. Sheppard -- A 10-year evaluation of flowering crabapple susceptibility to apple scab in Ohio / Elton M. Smith -- Fungicides for the control of diseases of ornamental plants: results of 1977 trials / C. C. Powell and James A. Chatfield -- An evaluation of fungicides on container-grown woody ornamentals during winter storage under microfoam / Christopher F. Rizzo, Elton M. Smith, and Thomas A. Fretz -- Resistance of maple cultivars and species to verticillium wilt: a preliminary report / H. A. J. Hoitink, T. D. Sydnor, and C. L. Wilso

WRF-CMAQ two-way coupled system with aerosol feedback: software development and preliminary results

Air quality models such as the EPA Community Multiscale Air Quality (CMAQ) require meteorological data as part of the input to drive the chemistry and transport simulation. The Meteorology-Chemistry Interface Processor (MCIP) is used to convert meteorological data into CMAQ-ready input. Key shortcoming of such one-way coupling include: excessive temporal interpolation of coarsely saved meteorological input and lack of feedback of atmospheric pollutant loading on simulated dynamics. We have developed a two-way coupled system to address these issues. A single source code principle was used to construct this two-way coupling system so that CMAQ can be consistently executed as a stand-alone model or part of the coupled system without any code changes; this approach eliminates maintenance of separate code versions for the coupled and uncoupled systems. The design also provides the flexibility to permit users: (1) to adjust the call frequency of WRF and CMAQ to balance the accuracy of the simulation versus computational intensity of the system, and (2) to execute the two-way coupling system with feedbacks to study the effect of gases and aerosols on short wave radiation and subsequent simulated dynamics. Details on the development and implementation of this two-way coupled system are provided. When the coupled system is executed without radiative feedback, computational time is virtually identical when using the Community Atmospheric Model (CAM) radiation option and a slightly increased (~8.5%) when using the Rapid Radiative Transfer Model for GCMs (RRTMG) radiation option in the coupled system compared to the offline WRF-CMAQ system. Once the feedback mechanism is turned on, the execution time increases only slightly with CAM but increases about 60% with RRTMG due to the use of a more detailed Mie calculation in this implementation of feedback mechanism. This two-way model with radiative feedback shows noticeably reduced bias in simulated surface shortwave radiation and 2-m temperatures as well improved correlation of simulated ambient ozone and PM2.5 relative to observed values for a test case with significant tropospheric aerosol loading from California wildfires