1,347 research outputs found
An Analysis of Milk Assembly Costs in the Greater Ohio Area: A Multi-Output Approach
A non-traditional multi-output cost function for milk haulers is estimated. Hauling firm outputs are (i) assembly miles, (ii) transport miles, and (iii) volume of milk hauled. Data were provided by 40 firms. The estimated cost function is shown to exhibit substantial economies of scale for all three joint outputs
Intercomparison of Multiple UV-LIF Spectrometers using the Aerosol Challenge Simulator
Measurements of primary biological aerosol particles (PBAPs) have been conducted worldwide using ultraviolet light-induced fluorescence (UV-LIF) spectrometers. However, how these instruments detect and respond to known biological and non-biological particles, and how they compare, remains uncertain due to limited laboratory intercomparisons. Using the Defence Science and Technology Laboratory, Aerosol Challenge Simulator (ACS), controlled concentrations of biological and non-biological aerosol particles, singly or as mixtures, were produced for testing and intercomparison of multiple versions of the Wideband Integrated Bioaerosol Spectrometer (WIBS) and Multiparameter Bioaerosol Spectrometer (MBS). Although the results suggest some challenges in discriminating biological particle types across different versions of the same UV-LIF instrument, a difference in fluorescence intensity between the non-biological and biological samples could be identified for most instruments. While lower concentrations of fluorescent particles were detected by the MBS, the MBS demonstrates the potential to discriminate between pollen and other biological particles. This study presents the first published technical summary and use of the ACS for instrument intercomparisons. Within this work a clear overview of the data pre-processing is also presented, and documentation of instrument version/model numbers is suggested to assess potential instrument variations between different versions of the same instrument. Further laboratory studies sampling different particle types are suggested before use in quantifying impact on ambient classification.Peer reviewe
Differential Gene Expression in Liver, Gill, and Olfactory Rosettes of Coho Salmon (Oncorhynchus kisutch) After Acclimation to Salinity.
Most Pacific salmonids undergo smoltification and transition from freshwater to saltwater, making various adjustments in metabolism, catabolism, osmotic, and ion regulation. The molecular mechanisms underlying this transition are largely unknown. In the present study, we acclimated coho salmon (Oncorhynchus kisutch) to four different salinities and assessed gene expression through microarray analysis of gills, liver, and olfactory rosettes. Gills are involved in osmotic regulation, liver plays a role in energetics, and olfactory rosettes are involved in behavior. Between all salinity treatments, liver had the highest number of differentially expressed genes at 1616, gills had 1074, and olfactory rosettes had 924, using a 1.5-fold cutoff and a false discovery rate of 0.5. Higher responsiveness of liver to metabolic changes after salinity acclimation to provide energy for other osmoregulatory tissues such as the gills may explain the differences in number of differentially expressed genes. Differentially expressed genes were tissue- and salinity-dependent. There were no known genes differentially expressed that were common to all salinity treatments and all tissues. Gene ontology term analysis revealed biological processes, molecular functions, and cellular components that were significantly affected by salinity, a majority of which were tissue-dependent. For liver, oxygen binding and transport terms were highlighted. For gills, muscle, and cytoskeleton-related terms predominated and for olfactory rosettes, immune response-related genes were accentuated. Interaction networks were examined in combination with GO terms and determined similarities between tissues for potential osmosensors, signal transduction cascades, and transcription factors
Assessing the tilt of the solar magnetic field axis through Faraday rotation observations
Context: Faraday rotation measurements of extragalactic radio sources during
coronal occultation allow assessment of both the electron density distribution
and the three-dimensional magnetic field topology in the outer solar corona.
Aims: We simulate the three-dimensional structure of both the coronal magnetic
field and the electron density distribution in order to reproduce the excess
Faraday rotation measures (RMs) of the occulted radio sources observed during
solar activity minimum. In particular, we infer the tilt of the solar magnetic
axis with respect to the rotation axis. Methods: We compare the output of the
model with Very Large Array (VLA) radio polarimetric measurements of a sample
of extragalactic sources observed in May 1997. Information on the magnetic
field geometry can be retrieved by fine-tuning the set of model free parameters
that best describe the observations. Results: We find that predicted and
observed Faraday rotation measures are in excellent agreement, thus supporting
the model. Our best-fitting model yields a tilt angle
of the solar magnetic axis with respect to the solar rotation axis around
Carrington Rotation 1923. This result is consistent with analogous but
independent estimates computed from the expansion coefficients of the
photospheric field observed at the Wilcox Solar Observatory (WSO).Comment: 8 pages, 5 figures, accepted for publication in A&
Ultraviolet observations of LMC nova 1988
The IUE obtained ultraviolet spectra of a nova in an external galaxy. The spectral features do not seem unusual for a nova at maximum but it is hoped to be able to follow it for a long enough time to be able to study the high ionization lines that appear when the density drops to lower values (the nebular stage). A high dispersion spectrum was also obtained to assist in the line identification and to study the line of sight to the LMC 1 deg of arc away from SN 1987A
Using Historical Sites To Help Teach The United States Survey
Everyone who teaches the American history survey in the United States has at hand some historical site that can be integrated into the curriculum. It might be a house or a neighborhood, a road trace, a fort, an old canal or railroad bed, or the remains of an iron furnace. Whatever the nature of the site, it holds the potential to bring a piece of the past vividly to life for students too often conditioned to rely on electronic images to stimulate their imaginations. Historic sites permit students literally to touch our past, and in that moment to make a connection to earlier Americans and their lives that cannot be duplicated in any classroom
Cwbr Author Interview: The Union War
Interview with Dr. Gary Gallagher, John L. Nau III Professor of History at the University of Virginia Interviewed by Nathan Buman
Civil War Book Review (CWBR): Today, I\u27m delighted to be joined by Gary Gallagher who is John L. Nau III Professor of History at the University of Virginia to discuss his most recent book The Union War. Professor Gallagher, thank you for talking with us today. Gary Gallagher (GG): Thanks for inviting me
Observations and simulations of nova Vul 1984 no. 2: A nova with ejecta rich in oxygen, neon, and magnesium
Nova Vul 1984 no. 2 was observed with IUE from Dec. 1984 through Nov. 1987. The spectra are characterized by strong lines from Mg, Ne, C, Si, O, N, and other elements. Data obtained in the ultraviolet, infrared, and optical show that this nova is ejecting material rich in oxygen, neon, and magnesium
Optical and ultraviolet observations of nova Vul 1987
The outburst for a nova discovered in Nov. 1987 and followed since then is summarized. Although it was possible to observe it with the IUE at maximum, its ultraviolet energy faded rapidly, and after the first 2 weeks it was impossible to observe it at IUE wavelengths. It is observed to form a thick dust shell and is in the nebular stage
Cold Harbor Syndrome: Balanced, Compelling Study\u27 Examines Grant\u27s Overland Miscalculations
Ulysses S. Grant\u27s offensive against Robert E. Lee\u27s entrenched Army of Northern Virginia at Cold Harbor on June 3, 1864, summons powerful images. Northern assaults that day stand alongside Ambrose E. Burnside\u27s attacks at Fredericksburg and John Bell Hood\u27s at Franklin as examples of seemingly poin...
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