1,752 research outputs found
Quantitative Metrics of Soil Structure and Relationships to Hydraulic Properties in a Vertic Argiudoll
Soil structure is a fundamental property referring to the morphology of soil aggregates and the network of void spaces between them. Structure affects many pedogenic, hydrological, and other ecosystem service processes. While its importance is generally recognized, the tortuous nature of soil structure and its variable size and expression make this property difficult to quantify, especially at the pit scale. The absence of quantitative soil structure metrics also inhibits the ability to accurately model water flux. This research explores the application of multistripe laser triangulation (MLT) scanning to a soil profile in the field. MLT scan data were analyzed for their ability to quantitatively characterize soil structure. The study site was located near Lawrence, KS in a Grundy soil series with vertic properties, where soil moisture sensors were installed in a lysimeter next to an exposed profile. Several logistical problems concerning MLT field operations and data processing are addressed in this work including: ambient light, MLT scanner positioning in relation to the soil surface, and post-processing procedures for the resulting data. MLT scans capture the profile surface along with areas of missing data, termed surface scan gaps (SSGs), which represent preferential flow paths (PFPs) actually observed in the soil. Metrics describing SSGs were first studied to determine whether the digital data could be related to conditions observed in the field. These metrics were then examined in relation to soil hydraulic parameters, especially saturated hydraulic conductivity (Ks) and water retention curve (WRC) parameters. Soil moisture data collected at the lysimeter, in conjunction with atmospheric data from an adjacent tower, were used as inputs for Hydrus 1-D to predict, then separately to verify hydraulic parameters that were obtained using quantitative soil structure metrics. Several close relationships were identified with WRC parameters such as α and n, as well as relationships with Ks. These connections, enabled by quantification of soil structure as a continuous rather than categorical variable through field-based measurements, present an opportunity to inform soil water flux models and advance the understanding of mechanisms underlying field-scale cycling of soil water
Investigation of thermodynamic mechanisms for the production of complex compounds essential for the origin of life Final report, 1 Oct. 1965 - 30 Sep. 1966
Thermodynamic equilibria in planetary atmospheres and in origin of organic matter - determination of amino acid pairing and sequences in protein
Investigation of thermodynamic mechanisms for the production of compounds essential for the origin of life First quarter technical report, Oct. 1 - Dec. 31, 1965
Expected thermodynamic equilibrium composition calculated for atmospheres of Earth, Venus, Mars, and Jupite
Corneoscleral laceration and ocular burns caused by electronic cigarette explosions
PURPOSE: To report cases of acute globe rupture and bilateral corneal burns from electronic cigarette (EC) explosions. METHODS: Case series. RESULTS: We describe a series of patients with corneal injury caused by EC explosions. Both patients suffered bilateral corneal burns and decreased visual acuity, and one patient sustained a unilateral corneoscleral laceration with prolapsed iris tissue and hyphema. A review of the scientific literature revealed no prior reported cases of ocular injury secondary to EC explosions; however, multiple media and government agency articles describe fires and explosions involving ECs, including at least 4 with ocular injuries. CONCLUSIONS: Given these cases and the number of recent media reports, ECs pose a significant public health risk. Users should be warned regarding the possibility of severe injury, including sight-threatening ocular injuries ranging from corneal burns to full-thickness corneoscleral laceration
Untangling cosmic magnetic fields: Faraday tomography at metre wavelengths with LOFAR
14 pages, 6 figures. Accepted for publication in "The Power of Faraday Tomography" special issue of GalaxiesThe technique of Faraday tomography is a key tool for the study ofmagnetised plasmas in the new era of broadband radio-polarisation observations. In particular, observations at metre wavelengths provide significantly better Faraday depth accuracies compared to traditional centimetre-wavelength observations. However, the effect of Faraday depolarisationmakes the polarised signal very challenging to detect at metre wavelengths (MHz frequencies). In this work, Faraday tomography is used to characterise the Faraday rotation properties of polarised sources found in data from the LOFAR Two-Metre Sky Survey (LoTSS). Of the 76 extragalactic polarised sources analysed here, we find that all host a radio-loud AGN (Active Galactic Nucleus). The majority of the sources (~64%) are large FRII radio galaxies with a median projected linear size of 710 kpc and median radio luminosity at 144 MHz of 4 × 10 26 W Hz -1 (with ~13% of all sources having a linear size > 1 Mpc). In several cases, both hotspots are detected in polarisation at an angular resolution of ~20'. One such case allowed a study of intergalactic magnetic fields on scales of 3.4 Mpc. Other detected source types include an FRI radio galaxy and at least eight blazars. Most sources display simple Faraday spectra, but we highlight one blazar that displays a complex Faraday spectrum, with two close peaks in the Faraday dispersion function.Peer reviewe
Comparing Probabilistic Models for Melodic Sequences
Modelling the real world complexity of music is a challenge for machine
learning. We address the task of modeling melodic sequences from the same music
genre. We perform a comparative analysis of two probabilistic models; a
Dirichlet Variable Length Markov Model (Dirichlet-VMM) and a Time Convolutional
Restricted Boltzmann Machine (TC-RBM). We show that the TC-RBM learns
descriptive music features, such as underlying chords and typical melody
transitions and dynamics. We assess the models for future prediction and
compare their performance to a VMM, which is the current state of the art in
melody generation. We show that both models perform significantly better than
the VMM, with the Dirichlet-VMM marginally outperforming the TC-RBM. Finally,
we evaluate the short order statistics of the models, using the
Kullback-Leibler divergence between test sequences and model samples, and show
that our proposed methods match the statistics of the music genre significantly
better than the VMM.Comment: in Proceedings of the ECML-PKDD 2011. Lecture Notes in Computer
Science, vol. 6913, pp. 289-304. Springer (2011
One- and two-photon resonant spectroscopy of hydrogen and anti-hydrogen atoms in external electric fields
The resonant spectra of hydrogen and anti-hydrogen atoms in the presence of
an external electric field are compared theoretically. It is shown that
nonresonant corrections to the transition frequency contain terms linear in the
electric field. The existence of these terms does not violate space and time
parity and leads to a difference in the resonant spectroscopic measurements for
hydrogen and anti-hydrogen atoms in an external electric field. The one-photon
1s-2p and the two-photon 1s-2s resonances are investigated
Wheat Fertilization Studies in Western Oklahoma Progress Report, 1953-54
The Oklahoma Agricultural Experiment Station periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311
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