Canada thistle regrowth control one year after herbicide application in winter wheat

Non-Peer ReviewedA field study was conducted to evaluate the effectiveness of several herbicides for long-term control of Canada thistle growing in winter wheat. Miscellaneous herbicides were applied at the five leaf stage of winter wheat in the presence of Canada thistle (30 plants per square meter). All herbicides gave effective control of Canada thistle top growth but did not increase yields compared to the weedy check. When Canada thistle control was evaluated one year after herbicide application, three of the nine treatments significantly reduced regrowth: 2,4-D amine at 840 g/ha, clopyralid + MCPA ester at 100 + 400 g/ha, and Clopyralid at 200 g/ha. These treatments reduced Canada thistle numbers by 58, 67, and 83 %, respectively. All herbicide treatments significantly reduced Canada thistle dry matter production one year after application as measured by shoot dry weight per square meter. Clopyralid at 100 g/ha in mixture with either 2,4-D or MCPA ester at 400 g/ha, and 2,4-D amine alone at 840 g/ha reduced dry weight of thistle shoots equally. Clopyralid at 200 g/ha was the most effective treatment tested; Canada thistle shoot dry weight per square meter was reduced by 93 % one year following treatment

Sonic levitation apparatus

A sonic levitation apparatus is disclosed which includes a sonic transducer which generates acoustical energy responsive to the level of an electrical amplifier. A duct communicates with an acoustical chamber to deliver an oscillatory motion of air to a plenum section which contains a collimated hole structure having a plurality of parallel orifices. The collimated hole structure converts the motion of the air to a pulsed. Unidirectional stream providing enough force to levitate a material specimen. Particular application to the production of microballoons in low gravity environment is discussed

Reduced avian body condition due to global warming has little reproductive or population consequences

Climate change has strong effects on traits such as phenology and physiology. Studies typically assume that climate-induced trait changes will have consequences for population dynamics, but explicit tests are rare. Body condition reflects energy storage and may directly affect how much can be invested in reproduction and survival. However, the causal pathway by which decreased body condition impacts population dynamics has never been quantified across multiple populations and species. Therefore, we lack a general understanding of the consequences of changes in condition for variables more relevant for conservation, such as population size. Using structural equation modeling, we investigate how temperature-induced changes in body condition affect reproduction, and the subsequent impact on population growth rates of 19 bird species across 80 Dutch sites over a 21-year period. Warmer temperatures were associated with decreased body condition, which led to both decreased and increased reproduction at different sites, cancelling out any overall effect. The indirect effect of temperature on population growth (via body condition and reproduction) only explained within-species variation in the total effects of temperature on population growth. Instead, the direct effect of temperature on population growth (unrelated to condition and reproduction) was the most important pathway underlying the total effects of temperature on population growth, suggesting that unknown variables are mediating this effect. About half of the species are expected to increase under global warming, but this variation was not associated with any species characteristic. Overall, body condition responses to global warming are common, but their consequences on reproduction and subsequently population growth contribute relatively little to the total temperature impacts on population dynamics. Given that warming temperatures have strong effects on population dynamics, understanding the pathways via which temperature impacts population dynamics will be crucial for our ability to predict climate change effects in the future and improve conservation efforts

Self-Stabilizing Byzantine Resilient Topology Discovery and Message Delivery

Traditional Byzantine resilient algorithms use $2f + 1$ vertex disjoint paths to ensure message delivery in the presence of up to f Byzantine nodes. The question of how these paths are identified is related to the fundamental problem of topology discovery. Distributed algorithms for topology discovery cope with a never ending task, dealing with frequent changes in the network topology and unpredictable transient faults. Therefore, algorithms for topology discovery should be self-stabilizing to ensure convergence of the topology information following any such unpredictable sequence of events. We present the first such algorithm that can cope with Byzantine nodes. Starting in an arbitrary global state, and in the presence of f Byzantine nodes, each node is eventually aware of all the other non-Byzantine nodes and their connecting communication links. Using the topology information, nodes can, for example, route messages across the network and deliver messages from one end user to another. We present the first deterministic, cryptographic-assumptions-free, self-stabilizing, Byzantine-resilient algorithms for network topology discovery and end-to-end message delivery. We also consider the task of r-neighborhood discovery for the case in which $r$ and the degree of nodes are bounded by constants. The use of r-neighborhood discovery facilitates polynomial time, communication and space solutions for the above tasks. The obtained algorithms can be used to authenticate parties, in particular during the establishment of private secrets, thus forming public key schemes that are resistant to man-in-the-middle attacks of the compromised Byzantine nodes. A polynomial and efficient end-to-end algorithm that is based on the established private secrets can be employed in between periodical re-establishments of the secrets

Front propagation into unstable and metastable states in Smectic C* liquid crystals: linear and nonlinear marginal stability analysis

We discuss the front propagation in ferroelectric chiral smectics (SmC*) subjected to electric and magnetic fields applied parallel to smectic layers. The reversal of the electric field induces the motion of domain walls or fronts that propagate into either an unstable or a metastable state. In both regimes, the front velocity is calculated exactly. Depending on the field, the speed of a front propagating into the unstable state is given either by the so-called linear marginal stability velocity or by the nonlinear marginal stability expression. The cross-over between these two regimes can be tuned by a magnetic field. The influence of initial conditions on the velocity selection problem can also be studied in such experiments. SmC$^*$ therefore offers a unique opportunity to study different aspects of front propagation in an experimental system

Velocity Selection for Propagating Fronts in Superconductors

Using the time-dependent Ginzburg-Landau equations we study the propagation of planar fronts in superconductors, which would appear after a quench to zero applied magnetic field. Our numerical solutions show that the fronts propagate at a unique speed which is controlled by the amount of magnetic flux trapped in the front. For small flux the speed can be determined from the linear marginal stability hypothesis, while for large flux the speed may be calculated using matched asymptotic expansions. At a special point the order parameter and vector potential are dual, leading to an exact solution which is used as the starting point for a perturbative analysis.Comment: 4 pages, 2 figures; submitted to Phys. Rev. Letter

Rotation and lithium abundance of solar-analog stars. Theoretical analysis of observations

Rotational velocity, lithium abundance, and the mass depth of the outer convective zone are key parameters in the study of the processes at work in the stellar interior, in particular when examining the poorly understood processes operating in the interior of solar-analog stars. We investigate whether the large dispersion in the observed lithium abundances of solar-analog stars can be explained by the depth behavior of the outer convective zone masses, within the framework of the standard convection model based on the local mixing-length theory. We also aims to analyze the link between rotation and lithium abundance in solar-analog stars. We computed a new extensive grid of stellar evolutionary models, applicable to solar-analog stars, for a finely discretized set of mass and metallicity. From these models, the stellar mass, age, and mass depth of the outer convective zone were estimated for 117 solar-analog stars, using Teff and [Fe/H] available in the literature, and the new HIPPARCOS trigonometric parallax measurements. We determine the age and mass of the outer convective zone for a bona fide sample of 117 solar-analog stars. No significant on-to-one correlation is found between the computed convection zone mass and published lithium abundance, indicating that the large A(Li) dispersion in solar analogs cannot be explained by the classical framework of envelope convective mixing coupled with lithium depletion at the bottom of the convection zone. These results illustrate the need for an extra-mixing process to explain lithium behavior in solar-analog stars, such as, shear mixing caused by differential rotation. To derive a more realistic definition of solar-analog stars, as well as solar-twin, it seems important to consider the inner physical properties of stars, such as convection, hence rotation and magnetic properties.Comment: 9 pages, 7 figure

Structural Stability and Renormalization Group for Propagating Fronts

A solution to a given equation is structurally stable if it suffers only an infinitesimal change when the equation (not the solution) is perturbed infinitesimally. We have found that structural stability can be used as a velocity selection principle for propagating fronts. We give examples, using numerical and renormalization group methods.Comment: 14 pages, uiucmac.tex, no figure

The adoption of servitization strategies by UK-based manufacturers

Almost all manufacturers offer services, but some use these as the basis for their competitive strategy. This is a growing area of interest among practitioners, policy makers, and academics, yet little is known about the adoption of servitization by UK manufacturers. In this paper a survey is presented that has been used to explore the extent, motivations, challenges, and successes of servitization within the business-to-business sector. The findings indicate, for example, that many manufacturers are succeeding with their service strategies, that they are attracted to these as a source of customer focus and revenue growth, and that such strategies require less organizational change than might be expected. Although the findings from the survey should be treated as preliminary, and further work is needed to confirm their reliability and insight, they indicate that servitization is proving to be a powerful competitive weapon for many companies