Kritische umweltbelastungen landwirtschaft (kul) ‐ eine methode zur analyse und bewertung der ökologischen situation von landwirtschaftsbetrieben

Es wird eine Methode vorgestellt, die es erlaubt, die ökologische Situation unterschiedlicher Landwirtschaftsbetriebe und Landnutzungssysteme einzuschätzen und vergleichend zu bewerten. Die Methode basiert auf der Quantifizierung von Gefährdungspotentialen und Festlegung einer kritischen Belastung, oberhalb der ökologische Schäden auftreten, die Nachhaltigkeit gefährdet ist oder ein begründetes Besorgnis vorliegt. Durch vergleichende Bewertung der quantifizierten Kriterien mit diesen kritischen Belastungen können ökologische Defizite erkannt und Korrekturerfordernisse abgeleitet werden. Gleichzeitig bilden die erarbeiteten Kritischen Umweltbelastungen Landwirtschaft (KUL) einen Rahmen begründeter Grenzwerte, der kontrollfähig die Umweltverträglichkeit von Landwirtschaftsbetrieben sichert und integrierte Landbauverfahren operationalisiert.     

Switchable surfactants

Many industrial applications that rely on emulsions would benefit from an efficient, rapid method of breaking these emulsions at a specific desired stage. We report that long-chain alkyl amidine compounds can be reversibly transformed into charged surfactants by exposure to an atmosphere of carbon dioxide, thereby stabilizing water/alkane emulsions or, for the purpose of microsuspension polymerization, styrene-in-water emulsions. Bubbling nitrogen, argon, or air through the amidinium bicarbonate solutions at 65 degrees C reverses the reaction, releasing carbon dioxide and breaking the emulsion. We also find that the neutral amidines function as switchable demulsifiers of an aqueous crude oil emulsion, enhancing their practical potential.     

Biomechanical Analysis of Torsion and Shear Forces in Lumbar and Lumbosacral Spine Segments of Nonchondrodystrophic Dogs

Objective— To determine stiffness and load–displacement curves as a biomechanical response to applied torsion and shear forces in cadaveric canine lumbar and lumbosacral specimens.
Study Design— Biomechanical study.
Animals— Caudal lumbar and lumbosacral functional spine units (FSU) of nonchondrodystrophic large-breed dogs (n=31) with radiographically normal spines.
Methods— FSU from dogs without musculoskeletal disease were tested in torsion in a custom-built spine loading simulator with 6 degrees of freedom, which uses orthogonally mounted electric motors to apply pure axial rotation. For shear tests, specimens were mounted to a custom-made shear-testing device, driven by a servo hydraulic testing machine. Load–displacement curves were recorded for torsion and shear.
Results— Left and right torsion stiffness was not different within each FSU level; however, torsional stiffness of L7-S1 was significantly smaller compared with lumbar FSU (L4-5–L6-7).
Ventral/dorsal stiffness was significantly different from lateral stiffness within an individual FSU level for L5-6, L6-7, and L7-S1 but not for L4-5. When the data from 4 tested shear directions from the same specimen were pooled, level L5-6 was significantly stiffer than L7-S1.
Conclusions— Increased range of motion of the lumbosacral joint is reflected by an overall decreased shear and rotational stiffness at the lumbosacral FSU.
Clinical Relevance— Data from dogs with disc degeneration have to be collected, analyzed, and compared with results from our chondrodystrophic large-breed dogs with radiographically normal spines.     

Laser-Doppler Measurements of Spinal Cord Blood Flow Changes During Hemilaminectomy in Chondrodystrophic Dogs with Disk Extrusion

Objectives— (1) To assess spinal cord blood flow (SCBF) during surgical treatment of disk extrusion in dogs and (2) to investigate associations between SCBF, clinical signs, presurgical MRI images, and 24-hour surgical outcome.
Study Design— Cohort study.
Animals— Chondrodystrophic dogs with thoracolumbar disk extrusion (n=12).
Methods— Diagnosis was based on clinical signs and MRI findings, and confirmed at surgery. Regional SCBF was measured intraoperatively by laser-Doppler flowmetry before, immediately after surgical spinal cord decompression, and after 15 minutes of lavaging the lesion. Care was taken to ensure a standardized surgical procedure to minimize factors that could influence measurement readings.
Results— A significant increase in intraoperative SCBF was found in all dogs (Wilcoxon's signed-rank test; P =.05) immediately after spinal cord decompression and after 15 minutes. Changes in SCBF were not associated with duration of clinical signs; initial or 24-hour neurologic status; or degree of spinal cord compression assessed by MRI.
Conclusion— SCBF increases immediately after spinal cord decompression in dogs with disk herniation; however, increased SCBF was not associated with a diminished 24-hour neurologic status.
Clinical Relevance— An increase in SCBF does not appear to be either associated with the degree of spinal cord compression or of a magnitude sufficient to outweigh the benefit of surgical decompression by resulting in clinically relevant changes in 24-hour outcome.     

Analysis of polymorphisms of cathepsin B and cystatin B impact on economically important traits in pigs raised in Poland

The cathepsins belong to an enzyme family of lysosomal proteinases, which have a wide spectrum of function in a lot of tissues and cell types. Cathepsin B is one of intracellular proteases, whose role is to carboxydipeptidyl activity. In turn, the cystatin B (CSTB) is an intracellular thiol proteinase inhibitor. In pigs, CTSB was mapped on 14 chromosome and linked to loci genes ATP2A2, ACTN2 and ACTA1, in the region where suggestive QTL for fat deposition and meat content were identified. The CSTB gene is localized on telomeric end (1/2) q46–q49 of SSC13 and on this chromosome QTLs for daily gain and birth weight were identified. Our investigation concerned analysis of effects A72C CTSB polymorphism and Asp62Asn CSTB missense mutation on carcass traits in Polish pigs population. The significant results of A72C of CTSB mutation was observed for several growth traits in Pietrain pigs. AC genotype characterized higher carcass yield and weight of ham and loin than in AA pigs (AC — 79.3%, 6.90 kg and 10.2 kg; AA — 77.8, 6.52 and 9.89, P < 0.01). The significant effect of Asp62Asn CSTB was in two traits of Polish Large White pigs: AA animals had higher daily gain and lower number days in test compared to animals with GG genotype (AA — 973 g, 162 days; GG — 882 g, 172 days) with favorable additive genetic effects of allele g173A on LSM. The selection on A allele of CSTB should lead to increasing level of fat. In turn, increasing in population, a C allele of CTSB should affect better meat content parameters in pig population. Overall, these two polymorphisms seem not to be directly association with carcass traits, but probably are linked to unknown QTLs localized on 13 and 14 chromosomes.     

Diversity and assembly of weed communities: contrasting responses across cropping systems

Diversity and weed community composition of mid-season plant stands and autumn seedbanks were examined in spring barley–red clover cropping systems that varied according to crop rotation, tillage and weed management. Weed plant and seed density data collected over 4 years were used in the calculation of species richness (number of species), evenness (Shannon's E) and diversity (Shannon's H′), and in multivariate analysis (canonical discriminant analysis) of weed communities. Weed diversity indices were low (H′ < 2.0) but sensitive to management practices. Evenness had intermediate values (E = 0.4–0.8), suggesting little evidence of truly dominant species, particularly in the seedbanks. The difference in the number of species between treatments was never large (approximately two to four species). Overall, diversity indices were highest in the low disturbance treatments, particularly those with minimum weed management. Factors affecting ordination were somewhat different from those affecting diversity. Tillage had little effect on weed diversity indices but had a more major role in determining weed community composition. Seedbanks in no-till and monoculture-chisel plough treatments appeared to have more distinctive species composition compared with other treatments. Weed species assembly in seedbanks showed little discrimination across treatments and over time, confirming the ability of seedbanks to buffer disturbances across a variety of cropping systems. The use of diversity indices revealed part of the complexity of weed communities associated with disturbance in cropping systems, whereas ordination singled out species–cropping systems associations, which may be more meaningful to weed management.