The Influence of Soil Moisture Conditions on the Absorption of Phosphorus by Plants from Calcareous Soils

Relationship between soil moisture and the absorption of phosphorus and other nutrients

A topographically controlled upwelling center off southern Vancouver Island

From January 1979 to June 1981 an oceanographic experiment off the west coast of Canada provided a unique view of a large annual upwelling event. The upwelling is driven by an interaction between the large scale coastal current systems and a narrow canyon that cuts the continental shelf. This interaction allows water to be raised from depths much greater than those normally expected from the classical wind-driven upwelling mechanisms...

Correlation scales, objective mapping and a statistical test of geostrophy over the continental shelf

We have constructed spatial structure functions for oceanographic variables, collected during 15 cruises off the coast of Vancouver Island, Canada over a 3 year period (1979–81), to determine the appropriate correlation function and unresolved noise level for objective mapping according to the Gauss-Markov theorem. The assumption of quasigeostrophic flow has been tested by comparing the longitudinal and transverse velocity shear structure functions derived from geopotential height fields with those derived from 6 current meter moorings. In addition objective maps of geopotential height imply current shears similar to the directly observed shear vectors, as would be expected under geostrophic control. Structure functions of geopotential height, temperature, salinity, and log-transformed phytoplankton chlorophyll a pigment concentration all have a broad maximum near a separation of 30 km, consistent with a dominant eddy wavelength of ≃60 km, also the estimated wavelength of the most unstable baroclinic disturbance. The sensitivity of the objective maps generated using the Gauss-Markov theorem to different correlation functions, length scales and noise levels was tested: where the sampling was well distributed, the patterns changed little.Temporal structure functions (for data from 25 cruises) of geopotential height, temperature and salinity are roughly cyclic with minima at time lags of 1 and 2 years. The structure functions increase monotonically with lags up to at least 90 days indicating that temporal changes during a ship survey (several days) are sufficiently small that the maps can be regarded as synoptic. Finally, a composite kinetic energy spectrum from a long term (≃3 years) current meter mooring at the edge of the continental shelf has well defined peaks in a band with 10–50 day periods (which we believe represents the mesoscale eddies with ≃60km wavelength), and at the annual and the major tidal and inertial periods

Simulation Study of TenTen: A new Multi-TeV IACT array

TenTen is a proposed array of Imaging Atmospheric Cherenkov Telescopes (IACT) optimized for the gamma ray energy regime of 10 TeV to 100 TeV, but with a threshold of ~1 to a few TeV. It will offer a collecting area of 10 km2 above energies of 10 TeV. In the initial phase, a cell of 3 to 5 modest-sized telescopes, each with 10-30 m2 mirror area, is suggested for an Australian site. A possible expansion of the array could comprise many such cells. Here we present work on configuration and technical issues from our simulation studies of the array. Working topics include array layout, telescope size and optics, camera field of view, telescope trigger system, electronics, and site surveys.Comment: 4 pages, 7 figures, submitted to Proceedings of the ICRC 2007, pdf forma

TenTen: A New Array of Multi-TeV Imaging Cherenkov Telescopes

The exciting results from H.E.S.S. point to a new population of gamma-ray sources at energies E > 10 TeV, paving the way for future studies and new discoveries in the multi-TeV energy range. Connected with these energies is the search for sources of PeV cosmic-rays (CRs) and the study of multi-TeV gamma-ray production in a growing number of astrophysical environments. TenTen is a proposed stereoscopic array (with a suggested site in Australia) of modest-sized (10 to 30m^2) Cherenkov imaging telescopes with a wide field of view (8 to 10deg diameter) optimised for the E~10 to 100 TeV range. TenTen will achieve an effective area of ~10 km^2 at energies above 10 TeV. We outline here the motivation for TenTen and summarise key performance parameters.Comment: 4 pages, 2 figures, proceedings of the 30th ICRC, Merida, Mexico, 200

Timing analysis techniques at large core distances for multi-TeV gamma ray astronomy

We present an analysis technique that uses the timing information of Cherenkov images from extensive air showers (EAS). Our emphasis is on distant, or large core distance gamma-ray induced showers at multi-TeV energies. Specifically, combining pixel timing information with an improved direction reconstruction algorithm, leads to improvements in angular and core resolution as large as ~40% and ~30%, respectively, when compared with the same algorithm without the use of timing. Above 10 TeV, this results in an angular resolution approaching 0.05 degrees, together with a core resolution better than ~15 m. The off-axis post-cut gamma-ray acceptance is energy dependent and its full width at half maximum ranges from 4 degrees to 8 degrees. For shower directions that are up to ~6 degrees off-axis, the angular resolution achieved by using timing information is comparable, around 100 TeV, to the on-axis angular resolution. The telescope specifications and layout we describe here are geared towards energies above 10 TeV. However, the methods can in principle be applied to other energies, given suitable telescope parameters. The 5-telescope cell investigated in this study could initially pave the way for a larger array of sparsely spaced telescopes in an effort to push the collection area to >10 km2. These results highlight the potential of a `sparse array' approach in effectively opening up the energy range above 10 TeV.Comment: Published in Astroparticle Physic

Ways Elementary Administrators Support Literacy Education

The work of an effective school principal is reflected in a variety of ways throughout the school. One area in which the principal\u27s influence is most clearly evident is literacy instruction. Studies conducted over the years provide support for this idea. In an investigation of the role of the school principal in reading instruction, Cox (1978) concluded that the leadership of the principal is vitally important in the development of an effective reading program. Chance (1991) also recognized the importance of principals as instructional leaders as she investigated principals\u27 own views of their involvement in the school reading program. In a summary statement, she maintained that the principal\u27s well planned, competent involvement in the instructional program is essential for program improvement at any level (p. 33)

A student perspective on the use of motivational strategies by their English-language literature instructors in an Omani University

Motivation has been recognized as one of the most influential factors in language learning. This study examines the frequency of use of motivational strategies by English-language literature instructors at the tertiary level in Oman as viewed by their students. A previous study [1] focused on teachers’ views of the frequency and importance of 48 motivational microstrategies, divided into 10 macrostrategies, in the Omani classroom. Findings indicate that teachers regarded all strategies as important while the degree of importance assigned to them correlated well with frequency of use. As that study involved only teacher participants, the current research utilized a modified version of its questionnaire to explore the frequency with which 65 Omani English-language literature learners believe these motivational strategies are employed by their instructors. Results suggest that participants believe their instructors often employ five of the featured macrostrategies. These include promoting self-confidence, creating a pleasant classroom environment, and making learning tasks engaging. However, the remaining five macrostrategies, such as promoting building group cohesiveness and familiarizing learners with L2 values, were rarely employed. These findings are compared to those from the previous study before a number of implications for motivating learners in Omani classrooms are offered