485 research outputs found

    I. Studies with red clover seed as related to color. II. Studies with the impurities found in red clover and alfalfa seed

    Get PDF
    TypescriptM.S. University of Missouri 1908Part I: The question of color in red clover seed is a matter to which practical farmers have come to attach some importance as an indication of the relative value of different samples. However, all do not hold the same opinion in regard to this. Many farmers believe that a sample of clover seed which has a great deal of purple color is better than a sample which contains more yellow. On the other hand, there are men equally observing and thoughtful, who maintain that the sample with the highest percent of yellow seed is the most viable and valuable. So far as we are aware, no accurate and conclusive work has ever been carried out in an attempt to determine the comparative value of clover seed of different colors. Believing that some definite knowledge on this subject might be of value this work is undertaken in an attempt to determine if possible whether there is any real basis for one or the other of these varying opinions, and if so, what some of the causes for these differences may be. Part II: Altogether too little attention is paid by the majority of farmers to the purity of the seed which they sow on their lands. This is particularly true, no doubt, with clover, alfalfa and grass seeds, as they carry on average a greater number of particularly obnoxious weed seeds than most of our other crops. New and troublesome weeds are often first observed in clover meadows, and it has often been noted that clover fields contain a great number of different weedy plants. It is a well-known fact that a very large number of our most obnoxious and troublesome weeds are those which have been introduced into this country through the agency of economic farm seeds purchased from European and other foreign markets. In order to secure some data in regard to the number and character of the weeds disbursed in this way in Missouri, samples of clover seed were secured from farmers throughout the State and from retail and wholesale seed merchants who supply more or less foreign seed to Missouri farmers

    Co-operative variety tests of corn : Variety tests of corn at Columbia

    Get PDF
    Cover title

    Evaluating the effectiveness of agricultural adaptation to climate change in preindustrial society

    Get PDF
    The effectiveness of agricultural adaptation determines the vulnerability of this sector to climate change, particularly during the preindustrial era. However, this effectiveness has rarely been quantitatively evaluated, specifically at a large spatial and long-term scale. The present study covers this case of preindustrial society in AD 1500–1800. Given the absence of technological innovations in this time frame, agricultural production was chiefly augmented by cultivating more land (land input) and increasing labor input per land unit (labor input). Accordingly, these two methods are quantitatively examined. Statistical results show that within the study scale, land input is a more effective approach of mitigating climatic impact than labor input. Nonetheless, these observations collectively improve Boserup's theory from the perspective of a large spatial and long-term scale.postprin

    Teixobactin kills bacteria by a two-pronged attack on the cell envelope

    Get PDF
    Antibiotics that use novel mechanisms are needed to combat antimicrobial resistance1–3. Teixobactin4 represents a new class of antibiotics with a unique chemical scaffold and lack of detectable resistance. Teixobactin targets lipid II, a precursor of peptidoglycan5. Here we unravel the mechanism of teixobactin at the atomic level using a combination of solid-state NMR, microscopy, in vivo assays and molecular dynamics simulations. The unique enduracididine C-terminal headgroup of teixobactin specifically binds to the pyrophosphate-sugar moiety of lipid II, whereas the N terminus coordinates the pyrophosphate of another lipid II molecule. This configuration favours the formation of a β-sheet of teixobactins bound to the target, creating a supramolecular fibrillar structure. Specific binding to the conserved pyrophosphate-sugar moiety accounts for the lack of resistance to teixobactin4. The supramolecular structure compromises membrane integrity. Atomic force microscopy and molecular dynamics simulations show that the supramolecular structure displaces phospholipids, thinning the membrane. The long hydrophobic tails of lipid II concentrated within the supramolecular structure apparently contribute to membrane disruption. Teixobactin hijacks lipid II to help destroy the membrane. Known membrane-acting antibiotics also damage human cells, producing undesirable side effects. Teixobactin damages only membranes that contain lipid II, which is absent in eukaryotes, elegantly resolving the toxicity problem. The two-pronged action against cell wall synthesis and cytoplasmic membrane produces a highly effective compound targeting the bacterial cell envelope. Structural knowledge of the mechanism of teixobactin will enable the rational design of improved drug candidates

    Molecular Insights into the Pathogenesis of Alzheimer's Disease and Its Relationship to Normal Aging

    Get PDF
    Alzheimer's disease (AD) is a complex neurodegenerative disorder that diverges from the process of normal brain aging by unknown mechanisms. We analyzed the global structure of age- and disease-dependent gene expression patterns in three regions from more than 600 brains. Gene expression variation could be almost completely explained by four transcriptional biomarkers that we named BioAge (biological age), Alz (Alzheimer), Inflame (inflammation), and NdStress (neurodegenerative stress). BioAge captures the first principal component of variation and includes genes statistically associated with neuronal loss, glial activation, and lipid metabolism. Normally BioAge increases with chronological age, but in AD it is prematurely expressed as if some of the subjects were 140 years old. A component of BioAge, Lipa, contains the AD risk factor APOE and reflects an apparent early disturbance in lipid metabolism. The rate of biological aging in AD patients, which cannot be explained by BioAge, is associated instead with NdStress, which includes genes related to protein folding and metabolism. Inflame, comprised of inflammatory cytokines and microglial genes, is broadly activated and appears early in the disease process. In contrast, the disease-specific biomarker Alz was selectively present only in the affected areas of the AD brain, appears later in pathogenesis, and is enriched in genes associated with the signaling and cell adhesion changes during the epithelial to mesenchymal (EMT) transition. Together these biomarkers provide detailed description of the aging process and its contribution to Alzheimer's disease progression

    International Factors and the 1964 Election

    Get PDF
    International issues are not usually seen as having been significant to the 1964 general election result. Harold Wilson made only limited references to foreign policy and defence during the campaign, while opinion polls showed that voters saw domestic questions as being far more important. Traditionally, international issues have had only a limited impact upon British general elections. But the 1964 election was one of the most closely run in history and this article argues that, interpreted broadly, international questions did have a real effect on the contest. The sitting prime minister Sir Alec Douglas-Home focused on the future of the nuclear deterrent for much of the campaign, while considerations about the country's relative decline in the world, reflected in chronic balance of payment problems, helped Labour's case that it was ‘time for a change’ at the top. Besides, the mid-1960s was a significant point for the country's global position: the post-war policy of ‘three circles’—in which Britain played a major role in Europe, maintained a global empire and influenced US policy via the ‘special relationship’—was being called into question. The question deserves to be asked, therefore, why there was not a more intense debate between the political leaders about Britain's international role
    corecore