Differentiation of strains of bean common mosaic virus

Pathogenicity and symptom expression of seventeen described isolates of bean common mosaic virus (BCMV) and five previously unreported isolates were compared on many bean cultivars (Phaseolus vulgaris L.). From these cultivars, a standard set of differentials were assigned to nine groups with different disease reactions. The twenty-two virus isolates comprised seven strain (pathotype) groups, three of which were divided into two subgroups each. To promote international standardization in BCMV research, recommendations are given for test conditions and procedures, criteria for strain differentiation, and maintenance of differential cultivars and virus strains.Samenvatting Zeventien beschreven stammen van het bonerolmozaïekvirus en vijf niet geïdentificeerde isolaten (Tabel 1) werden bestudeerd op een uitgebreide reeks van toetsrassen. De meeste van deze toetsrassen waren in de literatuur als zodanig vermeld, maar door de desbetreffende onderzoekers waren vaak verschillende series toetsrassen gebruikt, hetgeen de onderlinge vergelijking van de stammen bemoeilijkte.De bedoeling van dit onderzoek was: vergelijking en indeling van de virusstammen, samenstelling van een standaard-toetsrassenserie en het ontwerpen en beschrijven van werden zowel in Wageningen als in Prosser, Washington, USA, uitgevoerd met dezelfde virusisolaten en dezelfde zaadmonsters van de toetsrassen.De toetsrassen konden op grond van hun differentiële reacties na inoculatie met de virusstammen worden ingedeeld in negen groepen. De rassen binnen een groep hebben hetzelfde resistentiespectrum t.o.v. een standaardserie virusstammen. Uit elke groep werden op grond van hun geschiktheid (duidelijkheid en reproduceerbaarheid van de symptomen) één of meer vertegenwoordigers gekozen, waaruit een standaardserie van toetsrassen werd samengesteld (Tabel 2).De 22 stammen en isolaten werden op grond van hun pathogeniteitsspectrum t.o.v. de standaardserie van toetsrassen ingedeeld in tien groepen en subgroepen (Tabel 1). De stammen en isolaten binnen een groep of subgroep hebben eenzelfde pathogeniteitsspectrum (Tabellen 4 en 6) en worden op grond daarvan als identiek beschouwd. De differentiële reacties tussen de rassen van de standaardserie en de virusstammen en-isolaten zijn vermeld in de Tabellen 3 en 5. Voorgesteld wordt om de naam van de eerstbeschreven stam van iedere groep te handhaven en de andere stammen in een groep of subgroep op te vatten als isolaten daarvan.De toetsmethodiek wordt uitvoerig beschreven om standaardisatie van de stammenidentificatie te bevorderen. Ter verklaring van de in de literatuur gevonden tegenstrijdigheden in de differentiële reactie van de toetsrassen wordt een negental mogelijke oorzaken genoemd, o.a. het gebruik van planten van toetsrassen die reeds vanuit zaad met een onbekende stam waren besmet en het gebruik van onzuivere virusstammen (mengisolaten).De auteurs stellen zich verantwoordelijk voor het distribueren (op aanvraag) van kleine zaadhoeveelheden van de toetsrassen en, op beperkte schaal, van in zaad aanwezige zuivere virusstammen aan onderzoekers die betrokken zijn bij de identificatie van de stammen van dit virus. Bovendien zal zaad van de standaardserie van toetsrassen worden gedeponeerd in het National Seed Storage Laboratory te Fort Collins, Colorado, USA, terwijl de virusstammen (in zaad) in bewaring worden gegeven bij de American Type Culture Collection te Rockville, Maryland, USA, waar ze beschikbaar zullen blijven voor verder onderzoek.     

Spatial theory in early conservation design: examples from Aldo Leopold’s work

Aldo Leo­pold is well known in North America as a conservationist, author, and promoter of the Land Ethic. Although Leo­polds work is rarely included in the realm of landscape ecology, he left several illustrations of an early spatial theory for conservation. While European geographer Troll published the term landscape ecology in 1939, Leo­pold was discovering the role of spatial configuration in European working landscapes, and began to apply the landscape ecology concepts to wildlife management and cooperative conservation in the US. With his own spatial language he wrote, mapped, and applied elements of pattern, process, and connectedness in the landscape. In this perspective piece I use three examples from Leo­polds work to demonstrate his contribution to spatial theory in early conservation design. First, this paper deciphers spatial elements conveyed through Leo­polds writing, drawing, and teaching in the early 1930s. Second, I re-interpret Leo­polds observations of the spatial design of remises from his visit to Silesia, Europe. Third, I show how the lessons from Silesia were applied to a landscape in Wisconsin, USA, involving both farmers and townspeople in cooperative implementation of a remise system. Collectively, a new perspective emerges on the early dialogue of landscape ecology and conservation across continents.This revised version was published online in May 2005 with corrections to the Cover Date.     

Coal science: basic research opportunities

More fundamental knowledge of coal (knowledge of its structure and its behavior during conversion processes) is essential before we can generate new technologies necessary for the efficient use of coal in the future. Herein are suggested specific basic research opportunities in the areas of coal characterization, gasification, combustion, and liquefaction, along with an assessment of the impact such research programs could have. Critical characterization needs include qualitative and quantitative determination of the chemical forms of carbon, oxygen, nitrogen, and sulfur and reliable methods for the measurement of surface area, pore volume, and weight-average molecular weights. Mechanistic studies aimed at increasing understanding of the thermal breakdown of the functionalities in coal, the behavior of coal in the presence of molecular and donor hydrogen environments, and carbon gasification and hydrocarbon synthesis reactions starting from carbon monoxide and hydrogen will lay the scientific foundation for the development of new processes for converting coal into clean usable fuels and chemicals.     

A mechanical comparison of 4.5 mm narrow and 3.5 mm broad plating systems for stabilization of gapped fracture models

OBJECTIVE: To evaluate and compare the mechanical properties of 4.5 narrow and 3.5 broad plating systems using their respective cortical and cancellous screws in unstable, central, and eccentric gap fracture models. STUDY DESIGN: Mechanical evaluation and comparison of 2 dynamic compression plate (DCP) systems. SAMPLE POPULATION: Eighteen cortical and 30 cancellous gapped fracture models. METHODS: DCP (4.5 mm narrow, 3.5 mm broad) with their respective cortical screws were applied to cortical bone density polyurethane foam blocks to construct center gap cortical fracture models that were tested in gap closing monotonic 4-point bending. DCP (4.5 mm narrow, 3.5 mm broad) with their respective cancellous screws were applied to cancellous bone density polyurethane foam blocks to construct eccentric gap cancellous fracture models. The cancellous constructs were tested in monotonic gap opening and gap closing cantilever bending and in cyclic axial loading. Univariate and multivariate repeated measures ANOVA were used to compare the maximum loads at failure of the 4.5 mm constructs and 3.5 mm constructs. RESULTS: The 4.5 mm narrow plating system withstood significantly higher loads at failure than the 3.5 mm broad plating system in 4-point bending (P<.0001) and gap opening cantilever bending (P<.0001). The 4.5 mm system failed in gap closing cantilever bending by plastic deformation of the plate, whereas the 3.5 mm system failed by screw pullout. There was no difference between the 2 systems in cyclic axial loading. CONCLUSION: Results indicate that the 4.5 mm narrow plating system has a mechanical advantage over the 3.5 mm broad plating system for stabilization of gapped fracture models. CLINICAL RELEVANCE: The 4.5 mm narrow plating system may be mechanically advantageous compared with the 3.5 mm broad plating system for stabilizing unreconstructed comminuted long bone fractures in large dogs.     

Collaborative scenario modeling reveals potential advantages of blending strategies to achieve conservation goals in a working forest landscape

Context

Broad-scale land conservation and management often involve applying multiple strategies in a single landscape. However, the potential outcomes of such arrangements remain difficult to evaluate given the interactions of ecosystem dynamics, resource extraction, and natural disturbances. The costs and potential risks of implementing these strategies make robust evaluation critical.

Objectives

We used collaborative scenario modeling to compare the potential outcomes of alternative management strategies in the Two Hearted River watershed in Michigan’s Upper Peninsula to answer key questions: Which management strategies best achieve conservation goals of maintaining landscape spatial heterogeneity and conserving mature forests and wetlands? And how does an increase in wildfire and windthrow disturbances influence these outcomes?

Methods

Scenarios were modeled using the VDDT/TELSA state-and-transition modeling suite, and resulting land cover maps were analyzed using ArcGIS, FRAGSTATS, and R statistical software.

Results

Results indicate that blending conservation strategies, such as single-ownership forest reserves and working forest conservation easements in targeted areas of the landscape, may better achieve these goals than applying a single strategy across the same area. However, strategies that best achieve these conservation goals may increase the sensitivity of the landscape to changes in wildfire and windthrow disturbance regimes.

Conclusions

These results inform decision-making about which conservation strategy or combination of strategies to apply in specific locations on the landscape to achieve optimum conservation outcomes, how to best utilize scarce financial resources, and how to reduce the financial and ecological risks associated with the application of innovative strategies in an uncertain future.

     

Woodland and floral richness boost bumble bee density in cranberry resource pulse landscapes

Landscape Ecology - Native pollinators provide an important ecosystem service for many pollination-dependent fruit crops, but require nesting and foraging resources in proximity to target crop...     

The social and spatial dynamics of community food production: a landscape approach to policy and program development

Community food production in the form of home gardening, community gardening, school gardening, and urban farming continues to increase in popularity in many parts of the world. This interest has led to public and private investment in community food production and increased need for urban agricultural planning as a way to manage growth and prioritize resource allocation. Municipal planning and thoughtful institutional support for the practice will require program evaluation and greater attention to the spatial composition and configuration of this widely dispersed practice. This article explores the results of community-supported landscape socio-ecological research in Madison, WI (USA) to assess the spatial and social dynamics of community food production. Results indicate that community food production resources are unevenly distributed across the study area. Historic community garden placement does appear to be consistent with community prioritization which dictates placing resources in areas with low median household income. However, home garden presence and recent community garden placement both occur in areas of higher than average median household income. Specific focus is placed on how an understanding of landscape placement and pattern has helped inform attempts to meet municipal and regional objectives in addressing urban food insecurity.     

Prehistoric,historic, and present settlement patterns related to ecological hierarchy in the Eastern Upper Peninsula of Michigan,U.S.A.

The distribution of human occupation across a landscape provides informationabout how people use the landscape, about patterns of economic development,and about social interactions of human groups. When the distributions areexamined over several thousand years, we gain an evolutionary understanding,not only of the people and their cultural patterns, but also of physicallandscape development. The focus of this assessment was to examine andcompare settlement patterns of prehistoric, historic, and present timeperiods, based on known cultural sites in the Eastern Upper Peninsula ofMichigan, U.S.A., and to generate hypotheses about the interaction ofsettlement pattern and landscape change at multiple scales. Patterns ofsettlement among the three time periods were compared at three geographicscales: by subregional ecosystems, by landscape ecosystems and by terraincharacteristics. The Michigan Bureau of History database of archaeologicalsites was searched for prehistoric habitation sites of Middle or LateWoodland period (ca. 3000-300 years before present). Historic occupationswere drawn from pre-European settlement landscape data based on General LandOffice survey notes of the 1850s. We extracted urban categories from landcover classified from Landsat Thematic Mapper imagery to measure presentoccupations. Spatial patterns and dynamics of settlement areas in each timeperiod were examined using the ARC/INFO geographic information system (GIS).Results showed a tendency for settlement in all time periods on the bedrockand lowland landscape groups near Great Lakes shorelines, generally occupyingslopes less than two percent. The distribution of present occupations, interms of both slope aspect and geographic subregion (multi-scalar), wassimilar to the distribution of prehistoric occupations. Both prehistoric andpresent sites were primarily south facing and were frequently found alongGreen Bay and Lake Michigan shorelines.