Study on the strength of straw in rye (Secale cereale L.) with the use of the method of the dynamic mechanical analysis

Five indices of the straw strength (elastic module, elastic limit, elastic deformation, ultimate strength, ultimate deformation) have been found for the third and the fourth internodes in mutant (vitreous culm) and normal rye plants. Considerable differences in mechanical properties of culms and in correlation between indices studied in mutant and normal rye genotypes have been revealed. It was shown that the dynamic indices of the mechanical properties can be used for the evaluation of the cereal genotypes in breeding.     

Environmental processes driving anchovy and sardine distribution in a highly variable environment: the role of the coastal structure and riverine input

Engraulis encrasicolus and Sardina pilchardus stocks are highly variable in terms of recruitment, biomass and spatial distribution. Changes in habitat conditions may influence both the survival of the early life stages and the adult stages. Detailed studies on the spatial distribution and habitat selection of such species have been performed in different areas of the world, highlighting the importance of environmental processes. The present study analyzes the spatial distribution of anchovy and sardine in the Tyrrhenian Sea in relation to environmental heterogeneity. Four acoustic surveys were carried out in this area in the period 2009–2014. Analysis of the environmental dataset permitted identification, in two specific areas, of a pattern of variables driving enrichment processes and impacting on the habitat suitability of the two species. In the northern and central parts of the study area, both anchovy and sardine showed a marked preference for shallower areas characterized by lower salinity. In these areas, PCA results on an environmental dataset highlighted a strong link between primary production, particulate organic carbon, distance from the mouth of the river, salinity and depth. A less clear picture was obtained for the southern part of the Tyrrhenian sea, characterized by a narrow continental shelf, moderately complex coastline morphology and the presence of very small rivers. Most of the anchovy biomass was found to be located in enclosed areas (gulfs) under the influence of relatively small rivers. This finding, taking into account that the surveys were carried out during the anchovy spawning period, highlights for such species a positive effect of the interaction between coastal morphology and riverine input, probably favoring food supply and retention of spawning products.     

Compression of Ice to 210 Gigapascals: Infrared Evidence for a Symmetric Hydrogen-Bonded Phase

Protonated and deuterated ices (H2O and D2O) compressed to a maximum pressure of 210 gigapascals at 85 to 300 kelvin exhibit a phase transition at 60 gigapascals in H2O ice (70 gigapascals in D2O ice) on the basis of their infrared reflectance spectra determined with synchrotron radiation. The transition is characterized by soft-mode behavior of the nu3 O-H or O-D stretch below the transition, followed by a hardening (positive pressure shift) above it. This behavior is interpreted as the transformation of ice phase VII to a structure with symmetric hydrogen bonds. The spectroscopic features of the phase persisted to the maximum pressures (210 gigapascals) of the measurements, although changes in vibrational mode coupling were observed at 150 to 160 gigapascals.     

Reduced radiative conductivity of low-spin (Mg,Fe)O in the lower mantle

Optical absorption spectra have been measured at pressures up to 80 gigapascals (GPa) for the lower-mantle oxide magnesiowüstite (Mg,Fe)O. Upon reaching the high-spin to low-spin transition of Fe2+ at about 60 GPa, we observed enhanced absorption in the mid- and near-infrared spectral range, whereas absorption in the visible-ultraviolet was reduced. The observed changes in absorption are in contrast to prediction and are attributed to d-d orbital charge transfer in the Fe2+ ion. The results indicate that low-spin (Mg,Fe)O will exhibit lower radiative thermal conductivity than high-spin (Mg,Fe)O, which needs to be considered in future geodynamic models of convection and plume stabilization in the lower mantle.