7,280 research outputs found
Potassium Relationships of Three Ohio Soils
Author Institution: The Ohio State University Agricultural Technical Institute; Department of Agronomy, The Ohio State UniversityThree Ohio soils, Hoytville clay, Brookston silty clay loam, and Wooster silt loam located at various branches of the Ohio Agricultural Research and Development Center, were studied. Bulk samples from each horizon were tested for exchangeable basic cations, pH, sulfuric acid extractable potassium (K+), and particle-size distribution. The surface horizons of each soil were characterized by measurement of cation exchange capacity, quantity-intensity adsorption isotherms for K+ and x-ray diffraction of the clay ( times greater than that for Wooster. Hoytville clay was predominantly illitic while the Brookston and Wooster clays were of a more mixed mineralogical nature. The potassium content and crystallinity of the illite in the Hoytville clay is lower than those of the Brookston and Wooster clays
Cationic Activities and the Exchange Phenomena of Plant Roots: Relationship to Practical Problems of Nutrient Uptake
Analysis of direct segregated boundary-domain integral equations for variable-coefficient mixed bvps in exterior domains
This is the post-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2013 World Scientific Publishing.Direct segregated systems of boundary-domain integral equations are formulated for the mixed (Dirichlet–Neumann) boundary value problems for a scalar second-order divergent elliptic partial differential equation with a variable coefficient in an exterior three-dimensional domain. The boundary-domain integral equation system equivalence to the original boundary value problems and the Fredholm properties and invertibility of the corresponding boundary-domain integral operators are analyzed in weighted Sobolev spaces suitable for infinite domains. This analysis is based on the corresponding properties of the BVPs in weighted Sobolev spaces that are proved as well.The work was supported by the grant EP/H020497/1 \Mathematical analysis of localised boundary-domain integral equations for BVPs with variable coefficients" of the EPSRC, UK
Observations of a propagating vortex in a tidal current
While observing the hydrodynamics and geomorphology of the entrance to Burrill Lake, a small estuary on the south coast of New South Wales, Australia, a striking vortex phenomenon was observed. This vortex is described and interpreted
Brief Note: Smooth-billed Ani (Crotophaga ani L.), a New Species of Bird for Ohio
Author Institution: Department of Biology, John Carroll University ; Department of Vertebrate Zoology, The Cleveland Museum of Natural HistoryA smooth-billed ani (Crotophaga ani L.) is reported from Ohio for the first time. The specimen (CMNH 68471) also represents the first inland state record for the United States. Confirmation of specific identity was obtained because of the significance of the record and some equivocal characteristics of the specimen. Care in field identification of extralimital anis is suggested
Localized boundary-domain singular integral equations based on harmonic parametrix for divergence-form elliptic PDEs with variable matrix coefficients
This is the post-print version of the Article. The official publised version can be accessed from the links below. Copyright @ 2013 Springer BaselEmploying the localized integral potentials associated with the Laplace operator, the Dirichlet, Neumann and Robin boundary value problems for general variable-coefficient divergence-form second-order elliptic partial differential equations are reduced to some systems of localized boundary-domain singular integral equations. Equivalence of the integral equations systems to the original boundary value problems is proved. It is established that the corresponding localized boundary-domain integral operators belong to the Boutet de Monvel algebra of pseudo-differential operators. Applying the Vishik-Eskin theory based on the factorization method, the Fredholm properties and invertibility of the operators are proved in appropriate Sobolev spaces.This research was supported by the grant EP/H020497/1: "Mathematical Analysis of Localized Boundary-Domain Integral Equations for Variable-Coefficient Boundary Value Problems" from the EPSRC, UK
Search for radial velocity variations in eight M-dwarfs with NIRSPEC/Keck II
Context. Radial velocity (RV) measurements from near-infrared spectra have
become a potentially powerful tool to search for planets around cool stars and
sub-stellar objects. As part of a large survey to characterize M-dwarfs using
NIRSPEC at Keck II, we obtained spectra of eight late M-dwarfs (spectral types
M5.0-M8.0) during two or more observing epochs per target. These spectra were
taken with intermediate spectral resolving powers (R \sim 20,000) in the
J-band.
Aims. We search for relative radial velocity variability in these late
M-dwarfs and test the NIRSPEC capability of detecting short period brown dwarf
and massive planetary companions around low-mass stars in the J-band (\approx
1.25 micron). Additionally, we reanalyzed the data of the M8-type star vB10
(one of our targets) presented in Zapatero Osorio et al. (2009), which were
obtained with the same instrumentation as our data.
Methods. [...]
Results. For the entire M-dwarf sample, we do not find any evidence of
relative RV variations induced by a short period brown dwarf or massive
planetary companion. The typical RV precision of the measurements is between
180 and 300 m/s, which is sufficient to detect hot Neptunes around M-dwarfs.
Also, we find that the spurious RV shift in Zapatero et al. (2009) of the star
VB10 was caused by asymmetries in the instrumental profile between different
observing epochs, which were not taken into account in their analysis.Comment: A&A, 7 pages, 5 figure
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