Effects of Intensive N-K Fertilization on Exchangeable Ca and K in a Soil Profile

Over a 4-yr period fertilizers having three N and five K levels in a factorial arrangement were applied in a replicated, randomized complete block design to coastal bermudagrass (Cynodon dactylon L.) growing on a Pembroke silt loam just north of Fayetteville. In the spring of the fifth year (1972) soil samples were taken from a 3.67-m profile of each plot. Nine depth samples from the profile of each plot were analyzed for exchangeable K and Ca. Potassium fertilizer, especially at the higher rates, and where no N was applied, greatly increased exchangeable K levels only in the top 45 cm of the profile; however, exchangeable Ca levels were decreased markedly in these same upper soil layers, and increased greatly at lower levels in the profile. The first increment of N reduced this effect of K fertilizer on exchangeable Ca, probably because of increased plant growth that resulted from N fertilization; this increased growth removed a larger portion of the fertilizer K. At the higher N rate the net change in exchangeable Ca was greater, but more varied between K treatments, with the highest level of N and K resulting in a net loss of Ca from the 3.67-m profile sampled

The Functional Form of Angular Forces around Transition Metal Ions in Biomolecules

A method for generating angular forces around $\sigma$-bonded transition metal ions is generalized to treat $\pi$-bonded configurations. The theoretical approach is based on an analysis of a ligand-field Hamiltonian based on the moments of the electron state distribution. The functional forms that are obtained involve a modification of the usual expression of the binding energy as a sum of ligand-ligand interactions, which however requires very little increased in CPU time. The angular interactions have simple forms involving sin and cos functions, whose relative weights depend on whether the ligands are $\sigma$- or $\pi$-bonded. They describe the ligand-field stabilization energy to an accuracy of about 10%. The resulting force field is used to model the structure of small clusters, including fragments of the copper blue protein structure. Large deviations from the typical square copper coordination are found when $\pi$-bonded ligands are present.Comment: Latex source, 9 postscript figure

ONSET OF THE RAINY SEASON OVER TROPICAL BRAZIL IN OBSERVATIONS AND A GENERAL CIRCULATION MODEL SIMULATION

The intent of this paper is to present and document the hypothesis that the influence of sea surface temperature (SST) on rainfall in tropical Brazil is largely through its influence on onset and end of the rainy season, rather than on rain rates during the rainy season itself. The observations are compared with one 50 year run of the Euro- pean Centre / Hamburg Atmospheric Model ver- sion 4.5 general circulation model (GCM), although in this abstract, although only the obser- vations are shown

Residual Effects of N-K Fertilization of Coastal Bermudagrass on Spring Populations of Weed Species

A Coastal bermudagrass (Cynodon dactylon L.) sod was treated during a five-year period with rates of N and K fertilizers ranging from none to high levels of both elements. In the spring of the sixth year differences in weed species and population densities among the treated plots were observed. Spring weed counts showed that high rates of N fertilizer reduced the number of weed species and the total broadleaf weed population density by 37 and 81%, respectively. The higher rates of K fertilizer also reduced the population density of common dandelion (Taraxacum officinale Weber) and yellow toadflax (Linaria vulgaris Hill),the two dominant broadleaf weed species. The grass weed population, predominantly crabgrass (Digitaria sanguinalis ,L. Scop.) was not affected significantly by either N or K fertilizer levels

Combined Spectral and Timing Analysis of the Black Hole Candidate MAXI J1659-152 Discovered by MAXI and Swift

We report on X-ray spectral and timing results of the new black hole candidate (BHC) MAXI J1659-152 with the orbital period of 2.41 hours (shortest among BHCs) in the 2010 outburst from 65 Rossi X-ray Timing Explorer (RXTE) observations and 8 simultaneous Swift and RXTE observations. According to the definitions of the spectral states in Remillard & McClintock (2006), most of the observations have been classified into the intermediate state. All the X-ray broadband spectra can be modeled by a multi-color disk plus a power-law with an exponential cutoff or a multi-color disk plus a Comptonization component. During the initial phase of the outburst, a high energy cutoff was visible at 30-40 keV. The innermost radius of the disk gradually decreased by a factor of more than 3 from the onset of the outburst and reached a constant value of 35 d_10 cos i^-1/2 km, where d_10 is the distance in units of 10 kpc and $i$ is the inclination. The type-C quasi-periodic oscillation (QPO) frequency varied from 1.6 Hz to 7.3 Hz in association with a change of the innermost radius, while the innermost radius remained constant during the type-B QPO detections at 1.6-4.1 Hz. Hence, we suggest that the origin of the type-B QPOs is different from that of type-C QPOs, the latter of which would originate from the disk truncation radius. Assuming the constant innermost radius in the latter phase of the outburst as the innermost stable circular orbit, the black hole mass in MAXI J1659-152 is estimated to be 3.6-8.0 M_solar for a distance of 5.3-8.6 kpc and an inclination angle of 60-75 degrees.Comment: 27 pages, 14 figures, accepted for publication in PAS

Book Reviews

Book reviews of: A Brutal Reckoning: Andrew Jackson, the Creek Indians, and the Epic War for the American South By Peter Cozzens (Knopf, 2023. Acknowledgements, maps, notes, index. Pp. 464. $35.00 hardback. ISBN: 9780525659457.) Resident Strangers: Immigrant Laborers in New South Alabama. By Jennifer E. Brooks. (Baton Rouge: Louisiana State University Press, 2022. Acknowledgements, illustrations, map, notes, bibliography, index. Pp. xii, 239.$45 cloth, $19.95 ebook. ISBN: 0807176658) Bloody Flag of Anarchy: Unionism in South Carolina during the Nullification Crisis. By Brian C. Neumann. (Baton Rouge: Louisiana State University Press, 2022. Acknowledgements, maps, notes, index. Pp. ix, 216.$45 hardcover. ISBN: 0807176900. A Day I Ain’t Never Seen Before: Remembering the Civil Rights Movement in Marks, Mississippi. By Joe Bateman and Cheryl Lynn Greenberg. (Athens: University of Georgia Press, 2023. Pp. xi, 310. ISBN: 0820363035) The Last Fire-Eater: Roger A. Pryor and the Search for a Southern Identity. By William A. Link. (Baton Rouge: Louisiana State University Press, 2023. Acknowledgements, illustrations, notes, index. Pp. 1, 123. ISBN: 0807178935.

Performance Testing of a Novel Off-plane Reflection Grating and Silicon Pore Optic Spectrograph at PANTER

An X-ray spectrograph consisting of radially ruled off-plane reflection gratings and silicon pore optics was tested at the Max Planck Institute for extraterrestrial Physics PANTER X-ray test facility. The silicon pore optic (SPO) stack used is a test module for the Arcus small explorer mission, which will also feature aligned off-plane reflection gratings. This test is the first time two off-plane gratings were actively aligned to each other and with a SPO to produce an overlapped spectrum. The gratings were aligned using an active alignment module which allows for the independent manipulation of subsequent gratings to a reference grating in three degrees of freedom using picomotor actuators which are controllable external to the test chamber. We report the line spread functions of the spectrograph and the actively aligned gratings, and plans for future development.Comment: Draft Version March 19, 201