Direct observation of continuous electric dipole rotation in flux-closure domains in ferroelectric Pb(Zr,Ti)O₃

Low-dimensional ferroelectric structures are a promising basis for the next generation of ultrahigh-density nonvolatile memory devices. Depolarization fields, created by incompletely compensated charges at the surfaces and interfaces, depress the polarization of such structures. Theory suggests that under conditions of uncompensated surface charges, local dipoles can organize in flux-closure structures in thin films and vortex structures in nano-sized ferroelectrics, reducing depolarization fields. However, the continuous rotation of the dipoles required in vortex structures and the behavior of unit cell dipoles in flux-closure structures have never been experimentally established. By aberration-corrected transmission electron microscopy, we obtained experimental evidence for continuous rotation of the dipoles closing the flux of 180° domains in a ferroelectric perovskite thin film.     

Enhanced glucosinolates in root exudates of Brassica rapa ssp. rapa mediated by salicylic acid and methyl jasmonate

Elicitation studies with salicylic acid (SA) and methyl jasmonate (MJ) inducing a targeted rhizosecretion of high levels of anticarcinogenic glucosinolates in Brassica rapa ssp. rapa plants were conducted. Elicitor applications not only led to an accumulation of individual indole glucosinolates and the aromatic 2-phenylethyl glucosinolate in the turnip organs but also in turnip root exudates. This indicates an extended systemic response, which comprises the phyllosphere with all aboveground plant organs and the rhizosphere including the belowground root system and also root exudates. Both elicitor applications induced a doubling in 2-phenylethyl glucosinolate in root exudates, whereas application of MJ enhanced rhizosecreted indole glucosinolates up to 4-fold. In addition, the time course study revealed that maximal elicitation was observed on the 10th day of SA and MJ treatment. This study may provide an essential contribution using these glucosinolates as bioactive additives in functional foods and nutraceuticals.     

Tree roots in canopy soils of old European beech trees—An ecological reassessment of a forgotten phenomenon

The formation of adventitious roots in humus accumulations in tree canopies is widely acknowledged from tropical and temperate rainforests, while the occurrence of those canopy roots in temperate tree species under mesic climates has been largely disregarded for ca. 100 years. Moreover, almost nothing is yet known of the ecological growth conditions or the structure or morphology of such canopy root systems. This study reports on the occurrence of tree fine roots in crown humus pockets of old European beech (Fagus sylvatica L.) trees. The aim was to compare these canopy roots with the fine roots in the terrestrial organic layer soil in terms of fine root biomass density, root morphological traits, ectomycorrhizal colonisation and chemical composition of the root tissue, and to relate these root traits to the chemical properties of the respective soils. Fine root biomass density in crown humus pockets was ca. 7 times higher than in the terrestrial organic layer, even though soil chemical properties of both rooting media were similar. Fine roots in the canopy differed from terrestrial fine roots by lower specific root tip abundance, specific root length, and specific root surface area, all of which points to a longer lifespan of the fine roots in the canopy. Moreover, canopy roots revealed a lower percentage of root tips colonised by ectomycorrhizal fungi than terrestrial roots (87% vs. 93%). Chemical composition of the root tissue in canopy and terrestrial soils was similar for most elements, but canopy roots showed lower P, Fe, and Al concentrations and a higher N/P ratio than terrestrial roots. Root P concentrations of both canopy and terrestrial fine roots were closely related to soil P concentration, but not to soil C/P or N/P ratios. On the other hand, tissue N of canopy roots, but not of terrestrial roots, revealed a clear dependence on soil N and C/N values, suggesting a more limited N availability in the canopy soil compared to the terrestrial organic layer. However, the overall small differences in soil chemical properties between canopy and terrestrial organic layer soil cannot explain the markedly higher volumetric root density in the crown humus and the differences in ecomorphological traits between canopy and terrestrial soil. Instead, it is speculated that these differences are more likely a result of temporarily high water availability in crown humus pockets due to high water flow along the surface of branches to the central crown parts of the beech trees.     

Spectropolarimetric diagnostics of thermonuclear supernova explosions

Even at extragalactic distances, the shape of supernova ejecta can be effectively diagnosed by spectropolarimetry. We present results for 17 type Ia supernovae that allow a statistical study of the correlation among the geometric structures and other observable parameters of type Ia supernovae. These observations suggest that type Ia supernova ejecta typically consist of a smooth, central, iron-rich core and an outer layer with chemical asymmetries. The degree of this peripheral asphericity is correlated with the light-curve decline rate of type Ia supernovae. These results lend strong support to delayed-detonation models of type Ia supernovae.     

Agro‐ecological classification and spatial demarcation of Western Europe: Results of an EU‐funded research programme

The paper presents a hierarchic system of agro‐environmental classification of regions and landscapes. At the highest level are agro‐climatic regions (AKR). Allocating soil data, these units are broken down to soil‐climatic regions (Boden‐Klima Regionen, BKR). The next level is defined by geological data, topography “typical patterns of land uses”; and results in landscape types (LT). The AKR are used to define the intensification level and the energy surplus of agro production. The BKR allow specific analysis of impacts to environment factors of farm production systems. In the LT, specific targets for sustainable production and landscape rehabilitation are developed. The results are proposals to refine European agro‐policy towards more environmentally oriented schemes. The data is also valid to control the positive environmental effects of farmers adaptation of schemes.     

Broken eggs decrease pH of rainbow trout (Oncorhynchus mykiss) ovarian fluid

Low pH of ovarian fluid is attributed to its inability to activate sperm motility. In the present study we sought if broken eggs are reason for the decrease of ovarian fluid pH. We examined if 1) there is relationship between turbidity of ovarian fluid (indicator of presence of broken eggs) and pH, and 2) there is a decrease in ovarian fluid pH after addition of broken eggs. We found a negative relationship between the turbidity and ovarian fluid pH. Addition of the content of broken eggs to ovarian fluid caused a decrease of pH and a decrease in ovarian fluid ability to activate sperm motility. Therefore it can be suggested that content of broken eggs decreases or negates the ability of ovarian fluid to activate sperm motility due to a decrease of pH.     

A field trial of infrared thermography as a non-invasive diagnostic tool for early detection of digital dermatitis in dairy cows

Infrared thermography (IRT) was used to detect digital dermatitis (DD) prior to routine claw trimming. A total of 1192 IRT observations were collected from 149 cows on eight farms. All cows were housed in tie-stalls. The maximal surface temperatures of the coronary band (CB) region and skin (S) of the fore and rear feet (mean value of the maximal surface temperatures of both digits for each foot separately, CB_max and S_max) were assessed. Grouping was performed at the foot level (presence of DD, n = 99; absence, n = 304), or at the cow level (all four feet healthy, n = 24) or where there was at least one DD lesion on the rear feet, n = 37). For individual cows (n = 61), IRT temperature difference was determined by subtracting the mean sum of CB_max and S_max of the rear feet from that of the fore feet.Feet with DD had higher CB_max and S_max (P < 0.001) than healthy feet. S_max was significantly higher in feet with infectious DD lesions (M-stage: M2 + M4; n = 15) than in those with non-infectious M-lesions (M1 + M3; n = 84) (P = 0.03), but this was not the case for CB_max (P = 0.12). At the cow level, an optimal cut-off value for detecting DD of 0.99 °C (IRT temperature difference between rear and front feet) yielded a sensitivity of 89.1% and a specificity of 66.6%. The results indicate that IRT may be a useful non-invasive diagnostic tool to screen for the presence of DD in dairy cows by measuring CB_max and S_max.     

Conversion of tropical moist forest into cacao agroforest: consequences for carbon pools and annual C sequestration

Tropical forests store a large part of the terrestrial carbon and play a key role in the global carbon (C) cycle. In parts of Southeast Asia, conversion of natural forest to cacao agroforestry systems is an important driver of deforestation, resulting in C losses from biomass and soil to the atmosphere. This case study from Sulawesi, Indonesia, compares natural forest with nearby shaded cacao agroforests for all major above and belowground biomass C pools (n = 6 plots) and net primary production (n = 3 plots). Total biomass (above- and belowground to 250 cm soil depth) in the forest (approx. 150 Mg C ha^?1) was more than eight times higher than in the agroforest (19 Mg C ha^?1). Total net primary production (NPP, above- and belowground) was larger in the forest than in the agroforest (approx. 29 vs. 20 Mg dry matter (DM) ha^?1 year^?1), while wood increment was twice as high in the forest (approx. 6 vs. 3 Mg DM ha^?1 year^?1). The SOC pools to 250 cm depth amounted to 134 and 78 Mg C ha^?1 in the forest and agroforest stands, respectively. Replacement of tropical moist forest by cacao agroforest reduces the biomass C pool by approximately 130 Mg C ha^?1; another 50 Mg C ha^?1 may be released from the soil. Further, the replacement of forest by cacao agroforest also results in a 70–80 % decrease of the annual C sequestration potential due to a significantly smaller stem increment.