Combining functional weed ecology and crop stable isotope ratios to identify cultivation intensity: a comparison of cereal production regimes in Haute Provence, France and Asturias, Spain

This investigation combines two independent methods of identifying crop growing conditions and husbandry practices—functional weed ecology and crop stable carbon and nitrogen isotope analysis—in order to assess their potential for inferring the intensity of past cereal production systems using archaeobotanical assemblages. Present-day organic cereal farming in Haute Provence, France features crop varieties adapted to low-nutrient soils managed through crop rotation, with little to no manuring. Weed quadrat survey of 60 crop field transects in this region revealed that floristic variation primarily reflects geographical differences. Functional ecological weed data clearly distinguish the Provence fields from those surveyed in a previous study of intensively managed spelt wheat in Asturias, north-western Spain: as expected, weed ecological data reflect higher soil fertility and disturbance in Asturias. Similarly, crop stable nitrogen isotope values distinguish between intensive manuring in Asturias and long-term cultivation with minimal manuring in Haute Provence. The new model of cereal cultivation intensity based on weed ecology and crop isotope values in Haute Provence and Asturias was tested through application to two other present-day regimes, successfully identifying a high-intensity regime in the Sighisoara region, Romania, and low-intensity production in Kastamonu, Turkey. Application of this new model to Neolithic archaeobotanical assemblages in central Europe suggests that early farming tended to be intensive, and likely incorporated manuring, but also exhibited considerable variation, providing a finer grained understanding of cultivation intensity than previously available

Genetic analysis of wheat domestication and evolution under domestication

Wheat is undoubtedly one of the world's major food sources since the dawn of Near Eastern agriculture and up to the present day. Morphological, physiological, and genetic modifications involved in domestication and subsequent evolution under domestication were investigated in a tetraploid recombinant inbred line population, derived from a cross between durum wheat and its immediate progenitor wild emmer wheat. Experimental data were used to test previous assumptions regarding a protracted domestication process. The brittle rachis (Br) spike, thought to be a primary characteristic of domestication, was mapped to chromosome 2A as a single gene, suggesting, in light of previously reported Br loci (homoeologous group 3), a complex genetic model involved in spike brittleness. Twenty-seven quantitative trait loci (QTLs) conferring threshability and yield components (kernel size and number of kernels per spike) were mapped. The large number of QTLs detected in this and other studies suggests that following domestication, wheat evolutionary processes involved many genomic changes. The Br gene did not show either genetic (co-localization with QTLs) or phenotypic association with threshability or yield components, suggesting independence of the respective loci. It is argued here that changes in spike threshability and agronomic traits (e.g. yield and its components) are the outcome of plant evolution under domestication, rather than the result of a protracted domestication process. Revealing the genomic basis of wheat domestication and evolution under domestication, and clarifying their inter-relationships, will improve our understanding of wheat biology and contribute to further crop improvement

The Effect of P2O5P_2O_5 and Heat Treatment on the Crystallization of Li2O⋅2SiO2−BaO⋅2SiO2(LS2−BS2)Li_2O \cdot 2SiO_2 - BaO \cdot 2SiO_2 (LS_2 - BS_2) Glass

In this paper, the effects of $P_2O_5$ and heat treatment on the crystalline phases and microstructure of lithium disilicate-barium disilicate glass were examined. A wider and broad peak in the differential thermal analysis curve indicates a presence of surface crystallization instead of volume crystallization despite the use of nucleating agent, $P_2O_5$. The heat treatment schedules were planned according to differential thermal analysis data. The controlled crystallization of the compositions studied was carried out using two-stage heat treatment procedure. The glass transition temperature, $T_{g}$ of the as-cast sample were used to determine the optimum nucleation temperature. The optimum nucleation temperature was determined to be 520°C. The crystallization was carried out at 720C and 880C for 15 min. Lithium disilicate and sanbornite was the major phases and moganite or coesite were also present depending on the heat treatment duration. Due to coexistence of lithium disilicate and barium disilicate phases, the change in the melting entropy prevented the formation of spherulitic morphology and recrystallization after further heat treatments. The rise in the crystallization temperature enhanced grain coarsening and formed massive microstructures

The Effect of Mechanical Alloying on the Microhardness and Fracture Toughness of BaTiO3BaTiO_3

In this work, the effects of mechanical alloying on the mechanical properties of $BaTiO_3$ were investigated. In order to examine the milling conditions and sintering parameters on the solid state formation of $BaTiO_3$, X-ray diffraction technique was used. After mechanical alloying process, nanosized powder mixtures were produced. Sintering temperatures were 600, 700, 800, 900, 1000, and 1200C and sintering duration was 1 h. Besides X-ray diffraction examinations, mechanical properties of the $BaTiO_3$ samples were determined by Vickers microhardness test

Investigation of Indentation Fracture Toughness (KIC) and Weibull Parameters of 0.25Li2O.2SiO2-0.75BaO.2SiO2 Glass-Ceramic

In the present study, mechanical properties of 0.25Li2O.2SiO2-0.75BaO.2SiO2 glass-ceramic were investigated. The trans-formations‘ temperatures were determined by DTA instrument. The optimum nucleation temperature was found to be 540°C. This suggested the crystallization temperatures as 675, 720 and 800°C. After carrying out crystallization heat treatments, Vickers indentation test was applied. In order to determine the indentation fracture toughness (KIC), crack half-length ‚c‘ of the samples was measured. To calculate KIC, Young’s modulus, E and the measured hardness, Hv were used. Using KIC and probability of fracture ‚P‘, ln ln[1/(1 − P)] – ln KIC graph was drawn based on the Weibull distribution equation. Consequently, Weibull modulus, ‚m‘ and scale parameter, ‚K0‘ were determined and compared with each other

The Effect of Milling Time and Sintering Temperature on Crystallization of BaFe₁₂O₁₉ Phase and Magnetic Properties of Ba-Hexaferrite Magnet

Barium hexaferrite samples were prepared by mechanical alloying using the stoichiometric amounts of BaCO₃ and Fe₂O₃ precursors followed by heat treatment applied in the temperature range 700-1150°C. It was found that the high energy ball mill with a milling rate enabled to obtain powders with the finer particles at the reduced milling time mechanical alloying of the initial powders linked to the formation of barium hexaferrite phase. The exothermic reaction peaks corresponding to the formation of BaFe₁₂O₁₉ phase shift from 928°C to 793°C for the increased milling time up to 6 h. This was resulted in improved magnetic properties that the Mₛ value of the as-blended sample sintered at 800°C rised from 31.16 emu/g to 53.46 emu/g after milling for 6 h. The saturation magnetization and remanence values of the samples mechanically alloyed for 3 h and sintered at 1150°C also increased to 63.57 emu/g and 31.26 emu/g, respectively, more than for 800°C and 900°C. The increase in the annealing temperature favours the formation of BaFe₁₂O₁₉ phase in the samples