Corn rootworm insecticides evaluated

Two integrated pest management strategies are used widely to protect corn roots from corn rootworm injury: crop rotation and insecticides. If corn is not rotated, or if extended diapause has been documented to occur in a particular field, then a soil insecticide might be necessary to protect the roots in 2000. The reason we say it might be necessary is because many fields do not have a rootworm population of a sufficient size to cause economic damage. Believe it or not, there are thousands of continuous cornfields across the state in which a rootworm insecticide is not necessary

Corn rootworm insecticide results

Labeled rates of corn rootworm insecticides were evaluated across Iowa during the past three years in six locations per year. Five of the fields were conventional-till (chisel plowed in the fall and field cultivated in the spring). The sixth field was no-till. Tests were conducted in various soil types and under various moisture conditions. All products were evaluated in replicated side-by-side tests for their ability to protect corn roots from corn rootworm larval injury

Seedcorn maggots love manured fields

Seedcorn maggots are occasional pests of both corn and soybean seeds prior to germination and can cause stand loss. Because this damage occurs below the soil surface, it may be difficult to determine the need for an insecticide. There are no rescue treatments for this insect, so you must apply an insecticide at planting time if economic damage is anticipated. When making your decision, consider field history, previous crop or cover, heavy manuring during the winter or spring, and possible delays in germination due to cool and wet soil conditions

Graduate Training, Current Affiliation and Publishing Books in Political Science

Scores of studies have measured the quality of political science departments. Generally speaking, these studies have taken two forms. Many have relied on scholars\u27 survey responses to construct rankings of the major departments. For example, almost 50 years ago Keniston (1957) interviewed 25 department chairpersons and asked them to assess the quality of various programs, and, much more recently, the National Research Council (NRC 1995) asked 100 political scientists to rate the “scholarly quality of program faculty” in the nation\u27s political science doctoral departments. In response to these opinion-based rankings, a number of researchers have developed what they claim to be more objective measures of department quality based on the research productivity of the faculty (Ballard and Mitchell 1998; Miller, Tien, and Peebler 1996; Robey 1979). While department rankings using these two methods are often similar, there are always noteworthy differences and these have generated an additional literature that explores the relationship between the rating systems (Garand and Graddy 1999; Jackman and Siverson 1996; Katz and Eagles 1996; Miller, Tien, and Peebler 1996)

Current Concepts and Trends in Human-Automation Interaction

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.The purpose of this panel was to provide a general overview and discussion of some of the most current and controversial concepts and trends in human-automation interaction. The panel was composed of eight researchers and practitioners. The panelists are well-known experts in the area and offered differing views on a variety of different human-automation topics. The range of concepts and trends discussed in this panel include: general taxonomies regarding stages and levels of automation and function allocation, individualized adaptive automation, automation-induced complacency, economic rationality and the use of automation, the potential utility of false alarms, the influence of different types of false alarms on trust and reliance, and a system-wide theory of trust in multiple automated aids

Time Scale for Rapid Draining of a Surficial Lake Into the Greenland Ice Sheet

A 2008 report by Das et al. documented the rapid drainage during summer 2006 of a supraglacial lake, of approximately 44×10^6 m^3, into the Greenland ice sheet over a time scale moderately longer than 1 hr. The lake had been instrumented to record the time-dependent fall of water level and the uplift of the ice nearby. Liquid water, denser than ice, was presumed to have descended through the sheet along a crevasse system and spread along the bed as a hydraulic facture. The event led two of the present authors to initiate modeling studies on such natural hydraulic fractures. Building on results of those studies, we attempt to better explain the time evolution of such a drainage event. We find that the estimated time has a strong dependence on how much a pre-existing crack/crevasse system, acting as a feeder channel to the bed, has opened by slow creep prior to the time at which a basal hydraulic fracture nucleates. We quantify the process and identify appropriate parameter ranges, particularly of the average temperature of the ice beneath the lake (important for the slow creep opening of the crevasse). We show that average ice temperatures 5–7  °C below melting allow such rapid drainage on a time scale which agrees well with the 2006 observations

The observational impact of dust trapping in self-gravitating discs

We present a 3D semi-analytic model of self-gravitating discs, and include a prescription for dust trapping in the disc spiral arms. Using Monte-Carlo radiative transfer we produce synthetic ALMA observations of these discs. In doing so we demonstrate that our model is capable of producing observational predictions, and able to model real image data of potentially self-gravitating discs. For a disc to generate spiral structure that would be observable with ALMA requires that the disc's dust mass budget is dominated by millimetre and centimetre-sized grains. Discs in which grains have grown to the grain fragmentation threshold may satisfy this criterion, thus we predict that signatures of gravitational instability may be detectable in discs of lower mass than has previously been suggested. For example, we find that discs with disc-to-star mass ratios as low as $0.10$ are capable of driving observable spiral arms. Substructure becomes challenging to detect in discs where no grain growth has occurred or in which grain growth has proceeded well beyond the grain fragmentation threshold. We demonstrate how we can use our model to retrieve information about dust trapping and grain growth through multi-wavelength observations of discs, and using estimates of the opacity spectral index. Applying our disc model to the Elias 27, WaOph 6 and IM Lup systems we find gravitational instability to be a plausible explanation for the observed substructure in all 3 discs, if sufficient grain growth has indeed occurred.Comment: 19 pages, 21 figures, accepted for publication in MNRA

Completely positive maps with memory

The prevailing description for dissipative quantum dynamics is given by the Lindblad form of a Markovian master equation, used under the assumption that memory effects are negligible. However, in certain physical situations, the master equation is essentially of a non-Markovian nature. This paper examines master equations that possess a memory kernel, leading to a replacement of white noise by colored noise. The conditions under which this leads to a completely positive, trace-preserving map are discussed for an exponential memory kernel. A physical model that possesses such an exponential memory kernel is presented. This model contains a classical, fluctuating environment based on random telegraph signal stochastic variables.Comment: 4 page

The fragmentation of protostellar discs: the Hill criterion for spiral arms

We present a new framework to explain the link between cooling and fragmentation in gravitationally unstable protostellar discs. This framework consists of a simple model for the formation of spiral arms, as well as a criterion, based on the Hill radius, to determine if a spiral arm will fragment. This detailed model of fragmentation is based on the results of numerical simulations of marginally stable protostellar discs, including those found in the literature, as well as our new suite of 3-D radiation hydrodynamics simulations of an irradiated, optically-thick protostellar disc surrounding an A star. Our set of simulations probes the transition to fragmentation through a scaling of the physical opacity. This model allows us to directly calculate the critical cooling time of Gammie (2001), with results that are consistent with those found from numerical experiment. We demonstrate how this model can be used to predict fragmentation in irradiated protostellar discs. These numerical simulations, as well as the model that they motivate, provide strong support for the hypothesis that gravitational instability is responsible for creating systems with giant planets on wide orbits.Comment: 11 page, 10 figures, submitted to MNRA