RELATIONSHIP OF SELECTED BIOPHYSICAL VARIABLES TO SOIL MOISTURE AND SOIL TEMPERATURE VARIABILITY

Soil moisture and soil temperature at 15, 61, and 91 cm depths were measured through use of a neutron probe and thermocouple/psychrometers, respectively, at 12 sample sites distributed along a 200 km east-west transect in west-central Oklahoma. The data were collected weekly from May 7 to August 13, 1985. Multiple regression analysis was used to explain soil moisture and soil temperature variability at the three sample depths through a combination of selected biophysical variables representing temporal and spatial site characteristics, meteorologic inputs, energy variables, and soil conditions. The multiple regression analysis showed that 83, 91, and 82% of the variation in soil moisture, and 79, 91, and 92% of the variation in soil temperature for the three depths sampled could be explained by a combination of the selected biophysical variables.     

Intermediate disturbance and patterns of species richness

Abstract

The intermediate disturbance hypothesis (IDH) predicts highest species diversity in environments experiencing intermediate intensity disturbance, after an intermediate timespan. Because many landscapes comprise mosaics with complex disturbance histories, the theory implies that each patch in those mosaics should have a distinct level of diversity reflecting the magnitude of disturbance and the time since it occurred. We model changing patterns of species richness across a landscape experiencing varied scenarios of simulated disturbance in order to predict first the variation of richness through time in individual patches, based on their disturbance histories, and then the changing patterns of richness across the landscape through time, representing the cumulative impact of changing richness within the individual patches. Model outputs show that individual landscape patches have highly variable species richness through time, with the trajectory reflecting the timing, intensity and sequence of disturbances. When the results are mapped across the landscape, the resulting temporal and spatial complexity reveals a distribution of biodiversity that is strikingly contingent on the details of disturbance history. These results illustrate the danger of generalization (in either data interpretation or management decisions), as IDH actually imposes a highly variable pattern of diversity.     

Computing residence times for flow towards a pumping well: nomograph solution and validity of the small draw-down approximation

A recent analytical model developed to compute the residence time of fluid flowing in an unconfined aquifer towards a single pumping well is examined. The solution is scaled and presented practically as a nomograph showing the relationship between the residence time, flow length and draw-down. In addition, a similar scaling process is undertaken for the same problem occurring in a confined aquifer so that the error introduced by approximating an unconfined system as a confined system can be understood over a wide range of conditions.

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Resumen Se examina un modelo analítico, recientemente desarrollado, para calcular el tiempo de residencia de un fluido, el cual está fluyendo dentro de un acuífero libre hacia un pozo de bombeo único. La solución después de ser ajustada, se presenta prácticamente como un nomograma, mostrando la relación entre el tiempo de residencia, la longitud del flujo y el abatimiento. Adicionalmente, un proceso similar de ajuste fue realizado para el mismo problema, pero bajo condiciones de acuífero confinado, por tanto el error causado por hacer la aproximación de un sistema libre como si fuera un sistema confinado, puede llegar a ser entendido para un rango amplio de condiciones.

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Résumé On analyse un modèle analytique récent pour calculer le temps de résidence dun fluide pendant son écoulement vers un puits de pompage dans une nappe libre. La solution a été mise-à-léchelle et présenté dune manière pratique, comme une nomogramme qui exprime la relation entre le temps de résidence, la distance de l› écoulement et le rabattement. De plus, on a utilisé un procédé similaire de mise-à-léchelle pour le même problème dans une nappe captive affin que lerreur introduite par lapproximation dune nappe libre par une nappe captive peut être interprétée pour une grande classe de conditions.

     

New U-Pb ages of zircons in the Owk Shale (Kurnool Group) with reflections on proterozoic porcellanites in India

Felsic tuff beds with some presumed sedimentary components were reported from the Owk Shale (Kurnool Group; bearing Neoproterozoic fossils) in the upper part of the sedimentary succession in the Cuddapah basin in India by Saha and Tripathy (2012a). Our optical and SEM petrographic study of three thin sections, however, indicates that the parent samples are sandy mudstones with variable amounts of a felsic volcaniclastic component. New highquality U-Pb (SHRIMP and LA-MC-ICPMS) ages of 133 detrital zircon grains from a sample show that one grain is ca. 1880 Ma, one grain is ca. 3300 Ma, and the ages of the remaining 131 grains fall between 2690 Ma and 2429 Ma, the population averaging 2522 ± 36 Ma. The data indicate that the zircons are detrital grains derived from the ca. 2.5 Ga granitic/gneissic/greenstone basement of the Dharwar cratons that also host minor older Archean enclaves. The single 1880 Ma grain could have come from a ca. 1.9 Ga LIP. In the absence of any younger magmatic zircon, the absolute age of the Owk Shale remains elusive.     

Low frequency edge waves over a trench-ridge topography adjoining a straight coastline

Abstract

The possible interaction of trapped midoceanic boundary waves with a nearby coastline is examined by considering a step trench-ridge topography adjoining a semi-infinite straight coastline. The full dispersion equation, including the effect of the earth's rotation, is derived for long waves over this topography. It is shown that the presence of the coastline begins to have a significant effect on the behaviour of quasigeostrophic ridge waves whenever the wave length is greater than three times the ridge coastline separation.

As an example, the dispersion curves are presented for the topography of the Heceta Bank off the coast of Oregon and it is conjectured that the presence of this off-shore ridge may provide an explanation for the anomalous direction of propagation of the 0.1 c.p.d. shelf wave reported by Mooers and Smith (1968).     

Dynamical conditions in planets and stars

With the available data in planets, stars and galaxies, it is studied the functions of angular momentaJ(M) and amounts of actionA _c(M) (associated to the non rotational terms in the kinetic energy). The results indicate that independently of how are these functionsJ(M),A _c(M) their ratioA _c/J remains a near invariant. It is independent also from the type of angular momenta: intrinsic spins of the bodies or the total angular (orbital) momenta of the bodies forming a system; for instance, the Solar System and the planets.The relationA _c(M) for the Solar System are analogous to these in the FGK stars of the main sequence, and the relationJ(M) (also for the Solar System) is analogous to the lower possible limit for binary stars.The different types of binary stars from the short period, detached systems to contactary systems, gives a range of functionsJ(M),A _c(M) that are the same that one can expect in stars with planetary systems. According to the detection limits given for planetary companions by Campbell, Walker and Yang (1988) (masses of less than 9 Jupiter masses and orbital periods of less than 50 years) we calculate the limits forJ(M) andA _c(M) This gives a lower limitA _c/J 1 associated to stars with planetary systems as 61 Cygni and to short period detached binaries. The upper limitA _c/J 16 correspond to planetary systems as the ours and probably to cataclysmic binaries. There are reasons to suspect that systems as the ours and in range 4 A _c/J 16 (with a lower limit analogous to contactary binaries as Algols and W Ursa Majoris) must be the most common type of planetary systems. The analogies with the functionsJ(M)A _c(M) for galaxies suggest cosmogonical conditions in the stellar formation.Independently of this, one can have boundary conditions for the Jacobi problem when applied to a collapsing cloud. Namely, from the initial stage (a molecular cloud) to the final stage (a formed stellar system: binary or planetary) the angular momenta and amounts of action decayed to 10^~4 the initial values, but in such a form thatA _c(t)/J(t) remains a near invariant.