Ion-exchange resin strips as plant root simulators

Non-Peer ReviewedIon-exchange resin strips have the potential to closely mimic the manner in which a plant root removes nutrient ions from the surrounding soil. A method was developed involving burial of resin strips in soil; followed by a de-ionized water and dilute HCl wash of the strips. In approximately 200 soil samples obtained from across Saskatchewan, the plant availability of nitrate, ammonium, phosphate, potassium and sulphate as predicted by resin strip burial was significantly correlated with the plant availability predicted by conventional chemical-based soil extractions. Growth chamber experiments were set up in which canola plants were grown on the soils and actual plant nutrient uptake compared to test-predicted availability. The ability of the resin strip burial to predict differences in availability of N and P to canola was similar to the conventional soil extractants, but for K and S the strip burial appeared to be a better predictor of observed differences in plant uptake

Leaf analysis as a guide to sulfur fertilization of legumes

Non-Peer ReviewedTissue analysis is a diagnostic tool which can be used in identifying S deficiencies and predicting S fertilizer requirements of crops. A water extraction procedure for removal and measurement of inorganic sulfate in plant leaves was developed and assessed as a measure of S availability in four legume crops. Relationships between sulfate concentration and yield were determined for alfalfa (Medicago sativa L.), chickpea (Cicer arietinum L.), faba bean (Vicia faba) and lentil (Lens culinaris) grown on two Saskatchewan soils, with five rates of S fertilizer supply, in a growth chamber experiment. The sulfate concentration in the leaf tissue was measured at the time of seventh leaf and early flowering stages to estimate the current S status of the plants. The results showed significant relationships between the water extractable sulfate in the leaf and the supply of available S in the soils. The water extraction procedure is recommended for routine analyses because of its simplicity and sensitivity

Structure formation in binary colloids

A theoretical study of the structure formation observed very recently [Phys. Rev. Lett. 90, 128303 (2003)] in binary colloids is presented. In our model solely the dipole-dipole interaction of the particles is considered, electrohidrodynamic effects are excluded. Based on molecular dynamics simulations and analytic calculations we show that the total concentration of the particles, the relative concentration and the relative dipole moment of the components determine the structure of the colloid. At low concentrations the kinetic aggregation of particles results in fractal structures which show a crossover behavior when increasing the concentration. At high concentration various lattice structures are obtained in a good agreement with experiments.Comment: revtex, 4 pages, figures available from authors due to size problem

What People Around the World Like And Dislike About American Society and Politics

As Pew Research Center surveys have documented, the United States' global reputation has shifted dramatically over the past two decades, often improving or declining depending on who is in the White House and the foreign policies they pursue. At the same time, many other factors have continued to shape how people see the U.S., including its vast cultural reach, its economic model and its divisive politics. A survey of 17 advanced economies highlights the complexity of America's international image. People in other publics find much to admire about the U.S., but they see many problems as well. Americans, for their part, also see both strengths and weaknesses in their society

Formal and finite order equivalences

We show that two families of germs of real-analytic subsets in $C^{n}$ are formally equivalent if and only if they are equivalent of any finite order. We further apply the same technique to obtain analogous statements for equivalences of real-analytic self-maps and vector fields under conjugations. On the other hand, we provide an example of two sets of germs of smooth curves that are equivalent of any finite order but not formally equivalent

M-flation and its spectators

M-flation is an implementation of assisted inflation, in which the inflaton fields are three N_c x N_c non-abelian hermitean matrices. The model can be consistently truncated to an effectively single field inflation model, with all ``spectator'' fields fixed at the origin. We show that starting with random initial conditions for all fields the truncated sector is not a late-time attractor, but instead the system evolves towards quadratic assisted inflation with all fields mass degenerate. Demanding the energy density during inflation to be below the effective quantum gravity scale, we find that the number of fields, and thus the assisted effect, is bounded N_c < 10^2.Comment: 26 pages, published versio

Superconducting and ferromagnetic phase diagram of UCoGe probed by thermal expansion

We report thermal expansion measurements on a single crystal of the superconducting ferromagnet UCoGe for magnetic fields applied along the main orthorhombic axes. The thermal expansion cell was mounted on a piezo-electric rotator in order to fine-tune the magnetic field angle. The superconducting and magnetic phase diagram has been determined. With our bulk technique we confirm the $S$-shape of the upper-critical field, $B_{c2}$, for $B \parallel b$ and reinforcement of superconductivity above 6 T. At the same time the Curie point shifts towards lower temperatures on increasing the field along the $b$-axis. This lends further support to theoretical proposals of spin-fluctuation mediated reinforcement of superconductivity for $B \parallel b$.Comment: 7 pages, 7 figure

Cross-National Differences in Individual Knowledge-Seeking Patterns: A Climato-Economic Contextualization

Electronic Knowledge Repository (EKR) is one of the most commonly deployed knowledge management technologies, yet its success hinges upon employees’ continued use and is further complicated in today’s multinational context. We integrate multiple theoretical linkages into a research model, conceptualizing knowledge-seeking as an instrumental behavior, adopting the technology acceptance model to characterize the individual-level continued EKR knowledge-seeking behavioral model, and drawing on the climato-economic theory to explain cross-national behavioral differences. Using hierarchical linear modeling (HLM), we test the model with data from 1352 randomly sampled knowledge workers across 30 nations. We find that two national-level factors, climate harshness and national wealth, interactively moderate the individual-level relationship between perceived usefulness (PU) and behavioral intention (BI) to continue seeking knowledge from EKR, such that the difference in the strength of this relationship is larger between poor-harsh and poor-temperate nations than between rich-harsh and rich-temperate nations. We find similar cross-level cross-national differences for the link between perceived ease of use (PEOU) and PU but not for the link between PEOU and BI. Implications for research and practice are discussed

Obstructions to embeddability into hyperquadrics and explicit examples

We give series of explicit examples of Levi-nondegenerate real-analytic hypersurfaces in complex spaces that are not transversally holomorphically embeddable into hyperquadrics of any dimension. For this, we construct invariants attached to a given hypersurface that serve as obstructions to embeddability. We further study the embeddability problem for real-analytic submanifolds of higher codimension and answer a question by Forstneri\v{c}.Comment: Revised version, appendix and references adde

Understanding Cross National Difference in Knowledge Seeking Behavioral Model: A Survival Perspective

Electronic Knowledge Repository (EKR) is one of the most commonly deployed knowledge management technologies, yet its success is hindered by employees’ underutilization and further complicated when implemented in the multinational context. To address these challenges, we propose a research model by conceptualizing employees’ knowledge seeking via EKR as a survival-centric behavior, identifying the technology acceptance model as the individual-level explanation for EKR use, and drawing on the thermal demands-resources theory for explaining cross national behavioral differences. Using hierarchical linear modeling, we tested the model with data from 1352 randomly sampled knowledge workers across 30 nations. The results reveal interesting cross national behavioral patterns. Specifically, thermal climates and national wealth at the macro-level interactively moderate individual-level relationships between perceived ease of use and perceived usefulness and between perceived usefulness and behavioral intention