Issues and pitfalls in method comparison studies

Method comparison studies are needed for validation of new methods of measurements, for example, non‐invasive blood pressure measurements against standard reference methods. After a brief introduction into method comparison studies, this paper is organized in three sections. The first section deals with the widely, though not always appropriately, used classical Bland‐Altman plot with the limits of agreement and its extensions with non‐constant bias and multiple observations. The second section comments on other statistical approaches including correlation coefficients, linear regressions and sensitivities and specificities which are sometimes seen in method comparison studies. The third section proposes the usage of linear mixed effects models as a flexible way to deal with questions associated with method comparison studies.     

Farmer-Community Connections and the Future of Ecological Agriculture in California

While questions about the environmental sustainability of contemporary farming practices and the socioeconomic viability of rural communities are attracting increasing attention throughout the US, these two issues are rarely considered together. This paper explores the current and potential connections between these two aspects of sustainability, using data on community members’ and farmers’ views of agricultural issues in California’s Central Valley. These views were collected from a series of individual and group interviews with biologically oriented and conventional farmers as well as community stakeholders. Local marketing, farmland preservation, and perceptions of sustainable agriculture comprised the primary topics of discussion. The mixed results indicate that, while many farmers and community members have a strong interest in these topics, sustainable community development and the use of sustainable farming practices are seldom explicitly linked. On the other hand, many separate efforts around the Valley to increase local marketing and agritourism, improve public education about agriculture, and organize grassroots farmland preservation initiatives were documented. We conclude that linking these efforts more explicitly to sustainable agriculture and promoting more engagement between ecologically oriented farmers and their communities could engender more economic and political support for these farmers, helping them and their communities to achieve greater sustainability in the long run. Sonja Brodt is a former program evaluation specialist with the University of California Integrated Pest Management Program. Her current research focuses on extension and adoption of integrated pest management strategies by California growers and the impacts of pesticide safety training programs on farmworkers. Gail Feenstra is a food systems analyst at the University of California Sustainable Agriculture Research and Education Program (SAREP). She coordinates SAREP’s Community Development and Public Policy grants program and conducts outreach and education to academic and community-based groups to build their capacity and leadership skills for developing sustainable community food systems. Robin Kozloff is a social science researcher and consultant in agricultural and land use policy. Karen Klonsky is an extension specialist at the University of California at Davis in the Department of Agricultural and Resource Economics. Her research focuses on the economic viability of organic and sustainable farming systems as well as the evolution of the organic market. Laura Tourte is county director and farm advisor at the University of California Cooperative Extension in Santa Cruz County. Her research and extension activities currently focus on farm management and marketing for small-scale growers.     

Effect of low-intensity grazing on the species-rich vegetation of traditionally mown subalpine meadows

Subalpine meadows, which traditionally were mown every other year, are particularly rich in plant species, especially forbs. Near Davos (Switzerland) we compared the vegetation of mown sites with that of sites grazed for up to 50 years by non-lactating cows. We recorded an overall mean of 51.5 plant species per 4×4 m plot. Among grazed sites, evenness decreased with time since conversion to grazing (−0.11 in 50 years; P<0.05), suggesting progressive vegetation change, which may eventually result in the loss of species. Ground cover by forbs tended to be higher in mown than in grazed sites (by 7.2%; P<0.1). The proportion of not-clonally colonising perennial species decreased after conversion to grazing (−7.72%; in 50 years, P<0.05), while the cover by graminoid species increased (+14.2% in 50 years; P<0.1). More intensively grazed sites had a lower cover of dwarf shrubs and higher cover of legume species (P<0.05). Because grazing negatively affects both botanical richness and agricultural quality, mowing of traditionally mown subalpine meadows should be maintained, and recently grazed meadows should be reconverted to mowing.     

Occurrence of Pythium Ultimum Var. Ultimum in a Greenhouse on Spitsbergen Island, Svalbard

Pythium ultimum var. ultimum was isolated from carrot seedlings with damping off and from soil used for growing the plant in a greenhouse on Spitsbergen Island, Svalbard. The fungus caused severe damping off of carrot, cucumber and tomato seedlings after artificial inoculation. The rDNA internal transcribed spacer sequences of the Svalbard isolate were identical to those of Canadian and Japanese isolates of P. ultimum var. ultimum. The results suggest that the pathogen in the greenhouse on Svalbard was probably introduced from temperate regions through contaminated plants and/or soil imported to the island. This is the first record of P. ultimum var. ultimum within the Arctic zone.     

Molecular cytogenetics and flow cytometry reveal conserved genome organization in <Emphasis Type="Italic">Pinus mugo</Emphasis> and <Emphasis Type="Italic">P. uncinata</Emphasis>

• Introduction   

The most common representatives of the European mountain pine complex (Pinus mugo s.l.) are P. mugo s.s. and Pinus uncinata.     

The influence of spaying and its timing relative to the onset of puberty on urinary and general behaviour in Labrador Retrievers

Benefits and risks of spaying on the behaviour of female dogs are controversially discussed. Increased aggressiveness and male urinary behaviour were postulated to be the consequence of masculinization after spaying in some female dogs. To investigate if spaying or its timing relative to the onset of puberty may have a masculinization effect, urinary behaviour, that is, frequency of urination, urinary posture and ground scratching after urination were recorded in 58 female Labrador Retrievers during 15 min of a daily walk with their owners. General behaviour of the dogs during the walks was assessed using an owner questionnaire. Data were analysed for age, reproductive status, lifetime of ovary exposure and/or time interval since spaying. Urinary behaviour of intact females (n = 12) and dogs spayed before (n = 17) or after (n = 29) puberty was similar and not influenced by age, lifetime of ovary exposure and/or time interval since spaying. Owners of spayed dogs described more frequent or more intense fear reaction in their animals in response to loud noises, unfamiliar objects approaching on or near the sidewalk, or if they were approached by unknown dogs barking, growling or jumping. In conclusion, we found no evidence of a masculinization effect after spaying on urinary behaviour in female Labrador Retrievers. In contrast to popular belief, gonadectomy did not inevitably result in a behaviourally more stable dog. Extrapolation of our findings from female Labrador Retrievers to other breeds should be performed with caution, as the effect of spaying on behaviour may differ among dog breeds.