Suitability and calibration of a rebound tonometer to measure IOP in rabbit and pig eyes

Objective To utilize the Icare tonometer TAO1 for intraocular pressure (IOP) determination in experimental animals. To calculate true IOP calibration functions for rabbit and porcine eyes. Animals Enucleated eyes of 3‐year‐old healthy experimental rabbits (New Zealand white), and healthy 1 year old experimental pigs (Deutsche Landrasse) were used for the determination of IOP. Procedures Manometric (Geuder GmbH, Heidelberg/Germany) and rebound tonometry (Icare tonometer TAO1, Icare, Helsinki/Finland) were used to record IOP in enucleated animal eyes (rabbit n = 2, pig n = 3). Results The Icare tonometer TAO1 measurements underestimated true IOP by 37–60% in rabbit eyes and 17–63% in porcine eyes. IOP values obtained by both rebound and manometric tonometry for rabbit and porcine eyes followed a linear regression curve. Linear functions were calculated to correct the Icare tonometer TAO1 measurements to true IOP for both rabbit (p = 1.4244p_ic + 4.2421) and porcine eyes (p = 1.0799p_ic + 5.8557). Conclusions The Icare tonometer TAO1 can be utilized for IOP determination in rabbit and porcine eyes when measured values are corrected with the appropriate linear function.     

A statistics primer

Statistical input into an experimental study is often not considered until the results have already been obtained. This is unfortunate, as inadequate statistical planning 'up front' may result in conclusions which are invalid. This review will consider some of the statistical considerations that are appropriate when planning a research study.     

Canopy reduction as a possible measure for adaptation of young Scots pine stand to insufficient precipitation in Central Europe

Climate change towards a warmer and dryer vegetation period may negatively impact growing conditions for Scots pine monocultures situated on dry, sandy soils in Central Europe. The purpose of the study was to evaluate the effect of thinning on precipitation throughfall in young Scots pine stands on typical pine sites. In 1992, observation of precipitation and throughfall started at the Tyniště research site (lowland of Eastern Bohemia) in a 7-year-old pine stand planted in rows at a stocking of ca 10,000 trees ha⁻¹. Throughfall was measured at weekly intervals during the growing season (April-September) by gauges randomly located in two treatments - variant 1C - Control without thinning and variant 2T - Thinned - and compared to precipitation at an open space outside of the canopy. The results demonstrated the positive effects of heavy low thinning (removal of 47% of the total number of trees and 31% of total pre-treatment basal area) on the water supply of young Scots pine stands. On the Thinned treatment, throughfall increased by 2-8% compared to Control plot. This positive effect persisted for six years after the first canopy reduction and the differences were significant for the first four years after thinning. After the second treatment (high thinning), throughfall on the Thinned treatment showed a nominal, but statistically insignificant increase. The likely reason for this result is that the application of a different type of thinning increased the variability of the canopy and, consequently, the effect of released crowns could not be detected.     

Availability of Microelements as Affected by Soil Reaction and Fertilization in Long-Term Field Experiments

Results presented in this paper come from two long-term fertilization experiments carried out in Skierniewice (since 1923) and _ yczyn (since 1960). The top layer of soil in Skierniewice contains a little more clay and silt (17%) than at _ yczyn (14%), but the climatic conditions are alike - the mean for many years shows the precipitation of 520mm and temperature 7,9°C. Soil samples for the determination of microelements were collected in the years 1999 and 2000 from the control plots (Ca) and from combinations corresponding to 3 fertilization systems: mineral (CaNPK), organic (Ca + FYM) and mixed organic-mineral (CaNPK + FYM). The contents of B, Cu, Zn, Mn were determined in 4 extract solutions: 0,01mol CaCl2, EDTA, 1mol HCl and HF (total contents). The paper presents average results for the last two years. The following amounts of microelements (%) in relation to the total contents in particular extract solutions were obtained: CaCl 2 m Cu 0,4< Zn 2,2< Mn 3,5 < B 5,0; EDTA - B 2,4 < Mn 5,7 < Zn 9,0 < Cu 13,9; HCl - B 7,8 < Cu 37,3 < Zn 37,6< Mn 72,5. The soil contents of readily soluble forms of Mn were significantly higher in non-limed than in limed soil, while the amounts of B, Cu and Zn were higher in limed soils as some amounts of Cu and Zn were present in lime fertilizers. In the system of mineral fertilization, some amounts of boron and zinc were introduced to the soil together with fertilizers, however, they were insufficient in view of nutritional requirements. On the other hand, in the organic-mineral system the amounts of introduced boron were adequate, copper and zinc twice higher and manganese four times higher. The use of mineral fertilization alone for 26 years, leads to soil depletion of zinc and copper and the use of manure alone enriches soil in those components.     

Can Polish wheat (Triticum polonicum L.) be an interesting gene source for breeding wheat cultivars with increased resistance to Fusarium head blight?

Nine spring lines of Polish wheat (Triticum polonicum) were compared with Kamut wheat and two common wheat cultivars. Plants were analyzed to determine morphometric parameters (plant height, spike length, spike density, grain weight per spike and single kernel weight) and some chemical properties of grain: content of protein, ash, fat, crude fiber, minerals and mycotoxins. The studied genotypes produced a relatively weak response to infection with Fusarium culmorum which was expressed by a decrease in grain weight per spike and single kernel weight by 13 % and over 6 %, respectively. The grain of T. polonicum was characterized by a significantly higher protein and ash content than the grain of common wheat (by 19.8 and 23.7 %, respectively) and considerably higher concentrations of fat and dietary fiber than Kamut wheat (by 30.2 and 17.4 %, respectively). In comparison with common wheat, the grain of the examined genotypes was significantly more abundant in sulfur, magnesium and potassium as well as zinc, iron, copper and molybdenum. It contained significantly less aluminum and strontium. The inoculation led to a significant increase in fusariotoxin levels in the grain of all studied genotypes, and the average concentrations of the above metabolites were lower in the grain of T. polonicum than in Triticum aestivum. Polish wheat may constitute valuable genetic material for breeding new wheat varieties characterized by a high nutritive value and satisfactory resistance to FHB.     

From inventory to consumer biomass availability—the ITOC model

Key message The application of the ITOC model allows the estimation of available biomass potentials from forests on the basis of National Forest Inventory data. The adaptation of the model to country-specific situations gives the possibility to further enhance the model calculations.

Context

With the rising demand for energy from renewable sources, up-to-date information about the available amount of biomass on a sustainable basis coming from forests became of interest to a wide group of stakeholders. The complexity of answering the question about amounts of biomass potentials from forests thereby increases from the regional to the European level.

Aims

The described ITOC model aims at providing a tool to develop a comparable data basis for the actual biomass potentials for consumption.

Methods

The ITOC model uses a harmonized net annual increment from the National Forest Inventories as a default value for the potential harvestable volume of timber. The model then calculates the total theoretical potential of biomass resources from forests. By accounting for harvesting restrictions and losses, the theoretical potential of biomass resources from forests is reduced and the actual biomass potentials for consumption estimated.

Results

The results from ITOC model calculations account for the difference between the amounts of wood measured in the forests and the actual biomass potentials which might be available for consumption under the model assumptions.

Conclusion

The gap between forest resource assessments and biomass potentials which are available for consumption can be addressed by using the ITOC model calculation results.

     

Indirect immunofluorescent assay for antinuclear antibodies on McCoy-Plovdiv serum-free cell line substrate

Indirect immunofluorescent assay for antinuclear antibodies (IIFA-ANA) on HEp-2 cell substrate is a widely used test for diagnosis of connective tissue diseases. Recently, serum-free fibroblast cell line McCoy-Plovdiv has been developed to provide an alternative substrate. The aim of the present study was to evaluate the diagnostic performance of IIFA-ANA on McCoy-Plovdiv cell substrate for systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) and compare it with that of the standard HEp-2 cell substrate. Sera from 72 patients with RA and 23 patients with SLE were tested with IIFA-ANA on both substrates. The control group consisted of 100 sera from healthy individuals. The agreement (Cohen's kappa) and the diagnostic performance (ROC analysis) of both methods were evaluated. IIFA-ANA on McCoy-Plovdiv cells proved to be comparable with the standard IIFA-ANA on HEp-2 cell substrate.     

Some remarks on eel management in lakes

The paper presents basic factors determining eel production in Polish lakes. Analysis of data from 582 lakes over 29 years (1950–1978) showed that ell yield in lakes is basically determined by the artificial stocking of eels. The relationship between eel catch and eel stocking is very close and to a certain extent independent of the fishing effort. Prospects of further development of eel management in Europe are presented, as well as basic problems facing this management on a general scale. A need is identified for further studies in this field.     

Wetland creation: early stages in colonization of phytoplankton and submerged macrophytes in hypereutrophic freshwater lagoons

1. Colonization by macrophyte and phytoplankton communities was recorded in the newly created freshwater wetland complex at the Wildfowl and Wetlands Trust (WWT), The Wetlands Centre, London. To attract particular bird species and to increase overall invertebrate and vertebrate biodiversity it was originally planned to establish a number of different submerged aquatic macrophyte communities in the water bodies. Early planting schemes were abandoned due to extensive growths of filamentous macroalgae. 2. During 1997 and 1998 hypereutrophic conditions prevailed in the lagoons with peak concentrations of total phosphorus (TP) in excess of 1000 mg m⁻³. Turbidity was high and dense algal crops and cyanobacterial blooms common, with chlorophyll a concentrations in excess of 40 mg m⁻³. 3. In 1999, a ‘switch’ in state occurred in the Sheltered Lagoon from a turbid lake dominated by cyanobacteria and filamentous macroalgae in 1998, to a clear lake, dominated by the macrophyte Myriophyllum spicatum L. with a mean biomass of 245 g dry weight m⁻²; concentrations of TP remained high (>200 mg m⁻³). 4. Possible causes for the switch in the Sheltered Lagoon are considered. Reduction in TP was not considered to be sufficient to trigger a switch. The smaller size (1.8 ha), with smaller fetch and greater protection from wind mixing may have reduced sediment suspension in the Sheltered Lagoon and, coupled with water level changes, may have created favourable light conditions for the establishment of M. spicatum. Implications for future design and management of the water bodies are considered. Copyright © 2000 John Wiley & Sons, Ltd.     

Towards an ultimate explanation for mixed‐species shoaling

The formation of social groups has important impacts on fitness for many animal species, with differences in group compositions resulting in a range of fitness outcomes for individuals. Recent interest in mixed‐species grouping, which extends from a large body of literature invested in understanding single‐species grouping, highlights novel complexities of group formation which relate to phenotypic, behavioural and physiological differences that naturally exist between species. Among fishes, mixed‐species shoaling is a common form of social grouping behaviour displayed across a range of marine and freshwater ecosystems. Research explaining mixed‐species shoaling shows some overlap with explanations for single‐species shoaling; however, it also demonstrates that distinct differences between species give rise to unique cost‐benefit trade‐offs which need to be incorporated into conceptual models of mixed‐species shoaling behaviour. Unique predation related trade‐offs may arise from inefficiency of the confusion effect, variation in vigilance between species and unequal species‐preferences shown by predators, whilst unique foraging‐related trade‐offs may arise from diet partitioning, variations in foraging behaviour and differences in competitive abilities between species. We review the literature on fitness outcomes associated with mixed‐species shoaling and present a new theoretical framework to explain the cost‐benefit trade‐offs for individuals within mixed‐species shoals. The framework incorporates both trade‐offs arising from differences between species and those arising from group size, the former having been largely ignored due to a focus on single‐species shoaling. Our framework is designed to inform future research striving to explain mixed‐species shoaling behaviour.