Simple procedural method for estimating on-site soil erosion

CER76-77DBS-RML-TJW38.Prepared for USDA Forest Service, Rocky Mountain Forest and Range Experiment Station.Includes bibliographical references (pages 37-38).February 1977

Mapping of potential landslide areas in terms of slope stability

CER78-79DBS-RML-TJW19.Contract no. 16-712.O1-CA.Prepared for USDA Forest Service, Rocky Mountain Forest and Range Experiment Station.Includes bibliographical references (pages 57-62).November 1978

Glomus intraradices dominates arbuscular mycorrhizal communities in a heavy textured agricultural soil

Arbuscular mycorrhizal fungal (AMF) spore communities were surveyed in a long-term field fertilization experiment in Switzerland, where different amounts of phosphorus (P) were applied to soil. Plots receiving no P as well as plots systematically fertilized in excess to plant needs for 31 years were used to test the hypothesis that application of P fertilizer changes the composition and diversity of AMF communities. AMF spores were isolated from the field soil, identified, and counted so as to quantify the effect of P fertilization on AMF spore density, composition, and diversity. Trap cultures were established from field soil with four host plants (sunflower, leek, maize, and Crotalaria grahamiana), and the spore communities were then analyzed in substrate samples from the pots. Altogether, nine AMF species were detected in the soil. No evidence has been acquired for effect of P fertilization on spore density, composition, and diversity of AMF in both the field soil and in trap cultures. On the other hand, we observed strong effect of crop plant species on spore densities in the soil, the values being lowest under rapeseed and highest under Phacelia tanacetifolia covercrop. The identity of plant species in trap pots also significantly affected composition and diversity of associated AMF communities, probably due to preferential establishment of symbiosis between certain plant and AMF species. AMF spore communities under mycorrhizal host plants (wheat and Phacelia in the fields and four host plant species in trap pots) were dominated by a single AMF species, Glomus intraradices. This resulted in exceptionally low AMF spore diversity that seems to be linked to high clay content of the soi

Kaehler submanifolds with parallel pluri-mean curvature

We investigate the local geometry of a class of K\"ahler submanifolds $M \subset \R^n$ which generalize surfaces of constant mean curvature. The role of the mean curvature vector is played by the $(1,1)$-part (i.e. the $dz_id\bar z_j$-components) of the second fundamental form $\alpha$, which we call the pluri-mean curvature. We show that these K\"ahler submanifolds are characterized by the existence of an associated family of isometric submanifolds with rotated second fundamental form. Of particular interest is the isotropic case where this associated family is trivial. We also investigate the properties of the corresponding Gauss map which is pluriharmonic.Comment: Plain TeX, 21 page

Night vision and other stories

These stories are mysteries. They deal with the mystery of human existence. High seriousness and slapstick are the paradoxical elements of this existence. The region in which these elements blur marks the sphere of the stories

Dressing preserving the fundamental group

In this note we consider the relationship between the dressing action and the holonomy representation in the context of constant mean curvature surfaces. We characterize dressing elements that preserve the topology of a surface and discuss dressing by simple factors as a means of adding bubbles to a class of non finite type cylinders.Comment: 36 pages, 1 figur

A detailed study of cholinium chloride and levulinic acid deep eutectic solvent system for CO2 capture via experimental and molecular simulation approaches

Choline chloride + levulinic acid deep eutectic solvent is studied as a suitable material for CO2 capturing purposes. The most relevant physicochemical properties of this solvent are reported together with the CO2 solubility as a function of temperature. The corrosivity of this solvent is studied showing better performance than amine-based solvents. A theoretical study using both density functional theory and molecular dynamics approaches is carried out to analyze the properties of this fluid from the nanoscopic viewpoint, and their relationship with the macroscopic behavior of the system and its ability for CO2 capturing. The behavior of the liquid–gas interface is also studied and its role on the CO2 absorption mechanism is analyzed. The reported combined experimental and theoretical approach leads to a complete picture of the behavior of this new sorbent with regard to CO2, which together with its low cost, and the suitable environmental and toxicological properties of this solvent, lead to a promising candidate for CO2 capturing technological applicationsMinisterio de Economı´a y Competitividad (Spain, project CTQ2013-40476-R) and Junta de Castilla y Leo´n (Spain, project BU324U1

MacDowell-Mansouri gravity and Cartan geometry

The geometric content of the MacDowell-Mansouri formulation of general relativity is best understood in terms of Cartan geometry. In particular, Cartan geometry gives clear geometric meaning to the MacDowell-Mansouri trick of combining the Levi-Civita connection and coframe field, or soldering form, into a single physical field. The Cartan perspective allows us to view physical spacetime as tangentially approximated by an arbitrary homogeneous "model spacetime", including not only the flat Minkowski model, as is implicitly used in standard general relativity, but also de Sitter, anti de Sitter, or other models. A "Cartan connection" gives a prescription for parallel transport from one "tangent model spacetime" to another, along any path, giving a natural interpretation of the MacDowell-Mansouri connection as "rolling" the model spacetime along physical spacetime. I explain Cartan geometry, and "Cartan gauge theory", in which the gauge field is replaced by a Cartan connection. In particular, I discuss MacDowell-Mansouri gravity, as well as its more recent reformulation in terms of BF theory, in the context of Cartan geometry.Comment: 34 pages, 5 figures. v2: many clarifications, typos correcte

La acetabuloplastia de Staheli en el tratamiento de la enfermedad de Legg-Calvé-Perthes en mayores de 6 años. Estudio preliminar

Objetivo: Valorar los resultados funcionales y radiográficos de la acetabuloplastia de Staheli como alternativa terapéutica en el tratamiento quirúrgico de la enfermedad de Legg-Calvé-Perthes de debut tardío.Material y método: Estudio retrospectivo de 7 pacientes con enfermedad de Legg-Calvé-Perthes tratados mediante acetabuloplastia de Staheli con un tiempo de seguimiento medio de tres años y tres meses. Se analizan parámetros clínicos (movilidad prequirúrgica y al final del seguimiento) así como parámetros radiográficos (clasificación de Herring, índice acetábulo-cabeza de Heyman-Herndon y el ángulo centro-borde de Wiberg) previos al tratamiento quirúrgico, tras el tratamiento quirúrgico y al final del seguimiento. Resultados: Tras el análisis estadístico de los índices radiográficos (índice acetábulo-cabeza de Heyman-Herndon así como ángulo de Wiberg) se objetivaron diferencias estadísticamente significativas entre la radiografía prequirúrgica y postquirúrgica, pero no se objetivaron diferencias estadísticamente significativas entre la postquirúrgica y la realizada al final del seguimiento. Por lo tanto, los índices radiográficos mostraron una mejora en sus parámetros que además se mantuvo estable en el tiempo. Ningún paciente presentó complicaciones debidas a la cirugía. La exploración física mostró una mejoría media de 10º en la rotación interna de la cadera. Conclusiones: La técnica de acetabuloplastia según Staheli es una opción quirúrgica que conduce a la mejora de los resultados radiográficos y funcionales con pocas complicaciones debidas al procedimiento.Objective: To evaluate the functional and radiographic results of Staheli's acetabuloplasty as therapeutic option in the surgical treatment of Legg-Calvé-Perthes's disease of late debut. Material and method: we did a retrospective study of seven patients with Legg-Calvé-Perthes's disease treated by means of Staheli's acetabuloplasty with an average follow-up of three years and three months. We analyzed clinical parameters (preoperative and "end of the follow-up" mobility) as well as radiographic parameters (Herring's classification, Heyman-Herndon's index and Wiberg's center-edge angle) before the surgical treatment, after the surgical treatment and at the end of the follow-up. Results: Any patients presented complications due to the surgery. The physical exploration showed an average improvement of 10º in the internal rotation of the hip. After the statistical analysis of the radiographic indexes (Heyman-Herndon's index as well as Wiberg's angle), there were statistically significant differences between the preoperative X-ray and the postoperative one, but there were no statistically significant differences between the postoperative one and the X-ray done at the end of the follow-up. Therefore, the radiographic indexes showed an improvement in these parameters that in addition kept stable in time. Conclusions: The technic of acetabuloplasty according to Staheli is a surgical option that leads to a good radiographic and functional result with few complications due to the procedure