Wasserhaushalt,Stoffeintrag, Stoffaustrag und biologische Studien im Naturpark Schönbuch bei Tübingen

Ohne Zusammenfassung (Prof. Agerer seit 1982 am Institut für Systematische Botanik, München). (Weilimdorf) (zuvor t?tig bei der FVA Stuttgart, siehe oben) (Hohenheim)     

Seasonal variation of soil respiration in a Pinus cembra forest at the upper timberline in the Central Austrian Alps

Soil respiration (R) of a 95-year-old Pinus cembra L. forest at the alpine timberline was measured continuously from October 2001 to January 2003 with an automated multiplexing gas exchange system. There was significant spatial variability in soil respiration, and R at a soil temperature of 10 degrees C (R10) decreased by about 20% m(-1) with increasing distance from the trunk. Needle litter and fine root density also decreased. The spatially averaged annual soil CO2 efflux was 35 g C m(-2) year(-1) in 2002. About 70% of the temporal variation in soil respiration could be explained by variations in soil temperature, whereas the influence of soil water potential and thus soil water content was negligible because soil water availability was supra-optimal.     

Age-related changes in ecosystem structure and function and effects on water and carbon exchange in ponderosa pine

As forests age, their structure and productivity change, yet in some cases, annual rates of water loss remain unchanged. To identify mechanisms that might explain such observations, and to determine if widely different age classes of forests differ functionally, we examined young (Y, approximately 25 years), mature (M, approximately 90 years) and old (O, approximately 250 years) ponderosa pine (Pinus ponderosa Dougl. ex P. Laws.) stands growing in a drought-prone region of central Oregon. Although the stands differed in tree leaf area index (LAIT) (Y = 0.9, M = 2.8, O = 2.1), cumulative tree transpiration measured by sap flow did not differ substantially during the growing season (100-112 mm). Yet when water was readily available, transpiration per unit leaf area of the youngest trees was about three times that of M trees and five times that of O trees. These patterns resulted from a nearly sixfold difference in leaf specific conductance (KL) between the youngest and oldest trees. At the time of maximum transpiration in the Y stand in May-June, gross carbon uptake (gross ecosystem production, GEP) was similar for Y and O stands despite an almost twofold difference in stand leaf area index (LAIS). However, the higher rate of water use by Y trees was not sustainable in the drought-prone environment, and between spring and late summer, KL of Y trees declined fivefold compared with a nearly twofold decline for M trees and a < 30% reduction in O trees. Because the Y stand contained a significant shrub understory and more exposed soil, there was no appreciable difference in mean daily latent energy fluxes between the Y stand and the older stands as measured by the eddy-covariance technique. These patterns resulted in 60 to 85% higher seasonal GEP and 55 to 65% higher water-use efficiency at the M and O stands compared with the Y stand.     

What is new about new forest owners? A typology of private forest ownership in Austria

With structural changes in agriculture, new types of forest owners have become increasingly important. This article develops an empirically-based typology of forest owners in Austria. Based on a representative survey and by means of cluster analysis, seven types of forest owners are identified. These types form a sequence, ranging from forest owners with a strong agricultural background to forest owners with no agricultural background at all. The latter exhibit markedly different behaviour in various respects, e.g. in their interest in forest-related information. The increasing number of ‘new’ forest owners raises important questions for forest policy, especially how policy instruments can reach these owners and how extension services can address them.     

Homogeneous shear stress field of wood in an Arcan shear test configuration measured by means of electronic speckle pattern interferometry: description of the test setup

Wood Science and Technology - Several studies have dealt with the problem of how to measure the shear modulus of small clear wood specimens, avoiding bias from normal compression, bending, tension...     

EFFECTS OF FLUID AND COMPUTED TOMOGRAPHIC TECHNICAL FACTORS ON CONSPICUITY OF CANINE AND FELINE NASAL TURBINATES

Turbinate destruction is an important diagnostic criterion in canine and feline nasal computed tomography (CT). However decreased turbinate visibility may also be caused by technical CT settings and nasal fluid. The purpose of this experimental, crossover study was to determine whether fluid reduces conspicuity of canine and feline nasal turbinates in CT and if so, whether CT settings can maximize conspicuity. Three canine and three feline cadaver heads were used. Nasal slabs were CT‐scanned before and after submerging them in a water bath; using sequential, helical, and ultrahigh resolution modes; with images in low, medium, and high frequency image reconstruction kernels; and with application of additional posterior fossa optimization and high contrast enhancing filters. Visible turbinate length was measured by a single observer using manual tracing. Nasal density heterogeneity was measured using the standard deviation (SD) of mean nasal density from a region of interest in each nasal cavity. Linear mixed‐effect models using the R package ‘nlme’, multivariable models and standard post hoc Tukey pair‐wise comparisons were performed to investigate the effect of several variables (nasal content, scanning mode, image reconstruction kernel, application of post reconstruction filters) on measured visible total turbinate length and SD of mean nasal density. All canine and feline water‐filled nasal slabs showed significantly decreased visibility of nasal turbinates (P < 0.001). High frequency kernels provided the best turbinate visibility and highest SD of aerated nasal slabs, whereas medium frequency kernels were optimal for water‐filled nasal slabs. Scanning mode and filter application had no effect on turbinate visibility.     

Comparison of the effects of propofol or alfaxalone for anaesthesia induction and maintenance on respiration in cats

ObjectiveTo compare the effects of propofol and alfaxalone on respiration in cats.Study designRandomized, ‘blinded’, prospective clinical trial.AnimalsTwenty cats undergoing ovariohysterectomy.MethodsAfter premedication with medetomidine 0.01 mg kg⁻¹ intramuscularly and meloxicam 0.3 mg kg⁻¹ subcutaneously, the cats were assigned randomly into two groups: group A (n = 10) were administered alfaxalone 5 mg kg⁻¹ minute⁻¹ followed by 10 mg kg⁻¹ hour⁻¹ intravenously (IV) and group P (n = 10) were administered propofol 6 mg kg⁻¹ minute⁻¹ followed by 12 mg kg⁻¹hour⁻¹ IV for induction and maintenance of anaesthesia, respectively. After endotracheal intubation, the tube was connected to a non-rebreathing system delivering 100% oxygen. The anaesthetic maintenance drug rate was adjusted (± 0.5 mg kg⁻¹ hour⁻¹) every 5 minutes according to a scoring sheet based on physiologic variables and clinical signs. If apnoea > 30 seconds, end-tidal carbon dioxide (Pe′CO₂) > 7.3 kPa (55 mmHg) or arterial haemoglobin oxygen saturation (SpO₂) < 90% occurred, manual ventilation was provided. Methadone was administered postoperatively. Data were analyzed using independent-samples t-tests, Fisher's exact test, linear mixed-effects models and binomial test.ResultsManual ventilation was required in two and eight of the cats in group A and P, respectively (p = 0.02). Two cats in both groups showed apnoea. Pe′CO₂ > 7.3 kPa was recorded in zero versus four and SpO₂ < 90% in zero versus six cats in groups A and P respectively. Induction and maintenance dose rates (mean ± SD) were 11.6 ± 0.3 mg kg⁻¹ and 10.7 ± 0.8 mg kg⁻¹ hour⁻¹ for alfaxalone and 11.7 ± 2.7 mg kg⁻¹ and 12.4 ± 0.5 mg kg⁻¹ hour⁻¹ for propofol.Conclusion and clinical relevanceAlfaxalone had less adverse influence on respiration than propofol in cats premedicated with medetomidine. Alfaxalone might be better than propofol for induction and maintenance of anaesthesia when artificial ventilation cannot be provided.     

Formation of hydroxyphenyl-pyranoanthocyanins in Grenache wines: precursor levels and evolution during aging

Grenache red wines were produced following three different winemaking techniques, that is, small-scale standard experimental wines and industrial-scale wines by both double-mash fermentation and fermentation in Ganimede vats. Wines were analyzed for their color properties, as well as the anthocyanin, flavonol, hydroxycinnamic acid, and pyranoanthocyanin profiles following alcoholic and malolactic fermentation. The evolution of pyranoanthocyanins and their corresponding precursors in the experimental wines was monitored at 6 and 10 months of aging. Wines produced by double-mash fermentation exhibited superior color properties compared to Ganimede wines and the experimental red wines, due to better extraction of flavonols and anthocyanins as well as a lower degree of polymerization. Pyranoanthocyanin formation varied within the different classes of pigments. Vitisins A and B were formed only during alcoholic fermentation. Pinotin A (i.e., the reaction product from malvidin 3-glucoside and caffeic acid) formation took place only during the aging process, whereas formation of hydroxyphenyl-pyranoanthocyanins derived from p-coumaric and ferulic acid followed two different pathways, that is, an enzymatically assisted production during fermentation and a pure chemical formation during aging.     

Validation of a real-time PCR for the quantitative estimation of a G143A mutation in the cytochrome bc1 gene of Pyrenophora teres

A single nucleotide polymorphism (SNP) in the cytochrome b gene confers resistance to strobilurin fungicides for several fungal pathogens. Therefore, on the basis of a change at amino acid position 143 from glycine to alanine, a real-time PCR assay was established for the quantitative detection of the analogous SNP in the cytochrome b sequence of Pyrenophora teres Drechsler, which causes barley net blotch. Allelic discrimination was achieved by using allele specific primers with artificially mismatched nucleic acid bases and minor groove binding probes. Validation parameters for the lower limits of the working range, namely limits of detection (LOD) and limits of quantification (LOQ), were statistically determined by the variance of calibration data, as well as by the variance of the 100% non-strobilurin-resistant allele DNA sample (blank values). It was found that the detection was limited by the variance of blank values (five in 801 458 copies; 0.0006%), whereas the quantification was limited by the variance of calibration data (37 in 801 458 copies; 0.0046%). The real-time PCR assay was finally used to monitor strobilurin-resistant cytochrome b alleles in barley net blotch field samples, which were already classified in in vivo biotests to be fully sensitive to strobilurins. All signals for strobilurin-resistant cytochrome b alleles were below the LOD, and therefore the results are in total agreement with the phenotypes revealed by biotests.