437,066 research outputs found
What should organic farmers grow: heritage or modern spring wheat varieties? Report from a study comparing yields, grain and bread quality
For a 100% organic value chain, we need more varieties suitable for organic cultivation. Varieties bred for organic growing is a challenge in small markets. Many breeding goals are equal for organic and conventional cereals. Hence, accessions failing qualification as commercial varieties may perform well in organic growing. A field experiment over two years was performed at two growing sites to compare 25 accessions of spring wheat, ranging from old heritage varieties to modern breeding lines. We assessed yield and agronomic characteristics, artisan bread baking quality and sensory characteristics. Modern accessions gave best yields. Old varieties had smaller kernels, less grain filling, lower falling numbers and SDS-sedimentation volumes, but higher concentrations of minerals, although the growing site has a strong effect. Bread from modern accessions performed best in a baking test. Several sensory characteristics such as juiciness, chew resistance, firmness, acid taste and vinegar odor varied between varieties. Heritage varieties have an important cultural value, and many consumers are willing to pay a significant premium price for such products. A premium price is required, since yield levels are often considerably lower
Differences in Yield Parameters of Emmer in Comparison with Old and New Varieties of Bread Wheat
Emmer wheat (Triticum diccocum Schrank) belonged to the most frequent species of cereals in the past. Nowadays, it is grown in arid and montane areas in particular. Interest in this cereal species has increased, as it is tolerant to biotic and abiotic stressing factors. Therefore, yield parameters were evaluated in three-year (2007, 2008 and 2010) trials that were carried out in two different localities in the Czech Republic. Results of the research were compared to characteristics of four old and two top
modern bread wheat (Triticum aestivum L.) cultivars. The emmer wheat varieties were resistant to usual wheat diseases. They formed their yield by a quantity of productive tillers (2.5), whereas the varieties of bread wheat had less productive tillers (1.5) per one plant. The distribution of assimilates was worse in the emmer wheat plants and it provoked a lower harvest index (0.33) there. Grain yield of the emmer wheat varieties reached 58% of the yield level of the mean of control bread wheat varieties. High crude protein content in grain (17.91%) was an advantage of the emmer wheat varieties; the control bread wheat varieties reached 13.73%. Protein content was positively influenced (P < 0.01) by an ability of the
emmer varieties to uptake as much nitrogen as possible from the soil during the flowering period. Adaptability to the land and climatic environmental conditions was another positive characteristic of the emmer wheat landraces in comparison with old and modern bread wheat varieties
Characteristic Varieties of Hypersurface Complements
We give divisibility results for the (global) characteristic varieties of
hypersurface complements expressed in terms of the local characteristic
varieties at points along one of the irreducible components of the
hypersurface. As an application, we recast old and obtain new finiteness and
divisibility results for the classical (infinite cyclic) Alexander modules of
complex hypersurface complements. Moreover, for the special case of hyperplane
arrangements, we translate our divisibility results for characteristic
varieties in terms of the corresponding resonance varieties.Comment: v2: much of the paper has been re-written, including a more detailed
introduction and updated reference
Limits of Chow groups, and a new construction of Chern-Schwartz-MacPherson classes
We define an `enriched' notion of Chow groups for algebraic varieties,
agreeing with the conventional notion for complete varieties, but enjoying a
functorial push-forward for arbitrary maps. This tool allows us to glue
intersection-theoretic information across elements of a stratification of a
variety; we illustrate this operation by giving a direct construction of
Chern-Schwartz-MacPherson classes of singular varieties, providing a new proof
of an old (and long since settled) conjecture of Deligne and Grothendieck.Comment: 23 pages, final version. Dedicated to Robert MacPherson on the
occasion of his 60th birthda
Anbauwürdigkeit alter im Vergleich zu modernen Braugersten
Cropping spring barley, long varieties with vigorous growth are desired in organic farming expecting better regulation of weeds. Six old varieties were compared to three modern varieties in a field trial during 2010 and 2011 nearby Freising, Bavaria. The modern varieties were the recommended varieties for Bavaria at beginning of the trial. Higher crop yields were determined for modern varieties with limitation for one of these varieties. The malt quality of the modern varieties was considerably better than for the old varieties. Vigorous growth and plant length was higher for all and for five of the six old in comparison to modern varieties, respectively. But no differences in weed pressure could be measured due to successful mechanical weed control. Additionally, the susceptibility to diseases and tendency to lodge (one exception) was estimated higher for old than for modern varieties. All in all, the breeding progress could be shown in this trial. Hence, the conclusion is that old varieties of spring barley were not a cropping alternative to modern varieties in organic farming
Diversity between and within farmers’ varieties of tomato from Eritrea
Tomato yields in Eritrea are low (15 Mg/ha) compared with 19 Mg/ha in Africa and 27 Mg/ha worldwide. This is partly caused by poor quality of varieties used. This study analysed the diversity among and heterogeneity within farmers’ varieties of tomato from Eritrea and compared these varieties with other African and Italian varieties. Fifteen simple sequence repeat (SSR) markers were used for the genetic analysis. Genetic similarities among the varieties were calculated and an Unweighted Pair Group Method with Arithmetic Mean analysis was performed. Furthermore, individual plants of varieties were genotyped to evaluate uniformity within varieties. A high degree of diversity was observed among the Eritrean varieties. Thirteen out of the 15 SSRs were polymorphic, with 2 to 5 alleles per marker. The dendrogram showed two major types of varieties: San-Marzano and Marglob. Eritrean varieties were closely related to old Italian varieties in both types. Analysis of the within-variety variation showed that the Eritrean tomato genotypes were less uniform than the other varieties, probably because of deliberate mixing. A survey among farmers showed that some of them purposely mixed seeds to prolong the harvesting period, for yield stability and stress tolerance. Farmers value ‘new material’ as a source of influ
Rigidity of Spreadings and Fields of Definition
Varieties without deformations are defined over a number field. Several old
and new examples of this phenomenon are discussed such as Bely\u \i\ curves and
Shimura varieties. Rigidity is related to maximal Higgs fields which come from
variations of Hodge structure. Basic properties for these due to P. Griffiths,
W. Schmid, C. Simpson and, on the arithmetic side, to Y. Andr\'e and I. Satake
all play a role. This note tries to give a largely self-contained exposition of
these manifold ideas and techniques, presenting, where possible, short new
proofs for key results.Comment: Accepted for the EMS Surveys in Mathematical Science
Force, content and the varieties of unity (old version)
[This is an old version which is superseded by the published version. I keep it here for the record, as it has been cited.]
A strict dichotomy between the force / mode of speech acts and intentional states and their propositional content has been a central feature of analytical philosophy of language and mind since the time of Gottlob Frege and Bertrand Russell. Recently this dichotomy has been questioned by philosophers such as Peter Hanks (2015, 2016) and Francois Recanati (2016), who argue that we can't account for propositional unity independently of the forceful acts of speakers and propose new ways of responding to the notorious 'Frege point' by appealing to a notion of force cancellation. In my paper I will offer some supplementary criticisms of the traditional view, but also a way of reconceptualizing the force-content distinction which allows us to preserve certain of its features, and an alternative response to the Frege point that rejects the notion of force cancellation in favor of an appeal to intentional acts that create additional forms of unity at higher levels of intentional organization: acts such as questioning a statement or order, or merely putting it forward or entertaining it; pretending to state or order; or conjoining or disjoining statements or orders. This allows us to understand how we can present a forceful act without being committed to it. In contrast, the Frege point confuses a lack of commitment to with a lack of commitment or force in what is put forward
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