Animal perception in gravel-bed rivers: scales of sensing and environmental controls on sensory information

Animals make decisions based on the sensory information that they obtain from the environment and other organisms within that environment. In a river, this information is transported, transmitted, masked, and filtered by fluvial factors and processes, such as relative roughness and turbulent flow. By interpreting the resultant signals, animals decide on the suitability of habitat and their reaction to other organisms. While a great deal is known about the sensory biology of animals, only limited attention has been paid to the environmental controls on the propagation of sensory information within rivers. Here, the potential transport mechanisms and masking processes of the sensory information used by animals in gravel-bed rivers are assessed by considering how the physical nature of sensory signals are affected by river hydromorphology. In addition, the physical processes that animals have the potential to directly perceive are discussed. Understanding the environmental phenomena that animals directly perceive will substantially improve understanding of what controls animal distributions, shifting emphasis from identifying correlations between biotic and abiotic factors to a better appreciation of causation, with benefits for successful management

Molecular basis for resistance of acanthamoeba tubulins to all major classes of antitubulin compounds

Tubulin is essential to eukaryotic cells and is targeted by several antineoplastics, herbicides, and antimicrobials. We demonstrate that Acanthamoeba spp. are resistant to five antimicrotubule compounds, unlike any other eukaryote studied so far. Resistance correlates with critical amino acid differences within the inhibitor binding sites of the tubulin heterodimers

Potato Leafhopper-Resistant Alfalfa: Yield Advantages and New Pest Management Guidelines

In 1997 several companies released new potato leafhopper-resistant alfalfa varieties. These products are not genetically engineered, like Bt com, but have had leafhopper resistance bred into them using classical plant breeding techniques. Our research is focusing on the yield advantages of these products, the mechanism(s) of resistance and its effect on the pest and natural enemy community, and the potential changes in insect pest management that will accompany their use

Defining wireworm risk with GIS

Research at Iowa State University recently helped develop an early warning system for Iowa fields at risk from wireworms, by using geographic information system (GIS) technology. This information should help producers returning Conservation Reserve Program (CRP) land to corn production locate their high-risk fields. They can then follow recommended scouting procedures and avoid significant amounts of unnecessary insecticide applications in fields where wireworms are not detected

Potato leafhopper management in alfalfa

Potato leafhoppers have made their annual migration from the southern United States back to the alfalfa fields of Iowa. Small populations are being reported from across the state. During the last couple of years, producers have been planting potato-leafhopper-tolerant alfalfa to help prevent yield loss from this insect. Leafhopper-tolerant alfalfa looks, grows, and feeds similar to traditional leafhopper-susceptible alfalfa. It is different from susceptible alfalfa because the symptoms of feeding are much less severe

The importance of biotic entrainment for base flow fluvial sediment transport

Sediment transport is regarded as an abiotic process driven by geophysical energy, but zoogeomorphological activity indicates that biological energy can also fuel sediment movements. It is therefore prudent to measure the contribution that biota make to sediment transport, but comparisons of abiotic and biotic sediment flux are rare. For a stream in the UK, the contribution of crayfish bioturbation to suspended sediment flux was compared with the amount of sediment moved by hydraulic forcing. During baseflow periods, biotic fluxes can be isolated because nocturnal crayfish activity drives diel turbidity cycles, such that night-time increases above day-time lows are attributable to sediment suspension by crayfish. On average, crayfish bioturbation contributed at least 36% (430 kg) to monthly baseflow suspended sediment loads; this biotic surcharge added between 4.7 and 13.54 t (0.19 to 0.55 t km-2 yr-1) to the annual sediment yield. As anticipated, most sediment was moved by hydraulic forcing during floods and the biotic contribution from baseflow periods represented between 0.43 and 1.24% of the annual load. Crayfish activity is nonetheless an important impact during baseflow periods and the measured annual contribution may be a conservative estimate because of unusually prolonged flooding during the measurement period. In addition to direct sediment entrainment by bioturbation, crayfish burrowing supplies sediment to the channel for mobilization during floods so that the total biotic effect of crayfish is potentially greater than documented in this study. These results suggest that in rivers, during baseflow periods, bioturbation can entrain significant quantities of fine sediment into suspension with implications for the aquatic ecosystem and baseflow sediment fluxes. Energy from life rather than from elevation can make significant contributions to sediment fluxes

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

Wireworms in Conservation Reserve: An Evaluation of Risk Using GIS Technology and Discovering Effective Sampling Techniques

The mission of the Conservation Reserve Program (CRP), introduced in 1985, is to reduce soil erosion and increase wildlife habitat by planting native cool-season grasses on highly erodible land. After 10 years of fallow conditions, farmers can expect any number of problems when returning this land to crop production. One probable result will be the occurrence of soil-insect pests, primarily wireworms (Coleoptera: Elateridae )

Assessing Homeless Population Size Through the Use of Emergency and Transitional Shelter Services in 1998: Results from the Analysis of Administrative Data from Nine US Jurisdictions

Objectives. This study reports findings from the first-ever systematic enumeration of homeless population size using data previously collected from administrative records of homeless services providers in nine US jurisdictions over a one year period. As such, it provides the basis for establishing an ongoing measure of the parameters of the homeless population and for tracking related trends on the use of homeless services over time. Methods. Each participating jurisdiction collected data through its homeless services management information systems for persons and families who use emergency shelter and transitional housing. The jurisdictions organized the data by a standardized reporting format. These data form the basis for reporting homeless population size, both in raw numbers and as adjusted for each jurisdiction’s overall population size, as well as the rate of turnover and average annual length of stay in emergency shelters and transitional housing. Results. Individual jurisdictions had annual rates of sheltered homelessness ranging from 0.1% to 2.1% of their overall population, and 1.3% to 10.2% of their poverty population. Annual population size was 2.5 to 10.2 times greater than the point-prevalent population size. Results are broken down for adults and families. Conclusions. The prevalence of homelessness varies greatly among the jurisdictions included in this study, and possible factors for this diversity are discussed. Future reports of this nature will furnish similar series of homeless enumerations across a growing number of jurisdictions, thereby providing a basis for exploring the effects of different contextual factors on local prevalence rates of homelessness