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... / samlet og fortsat af Hans de Hofman
Get PDF... / SAMLET OG FORTSAT AF HANS DE HOFMAN
Den Danske Atlas Eller Konge-Riget Dannemark : Med dets Naturlige Egenskaber, Elementer, Indbyggere, Væxeter, Dyr og andre Affødninger, dets gamle Tildragelser og nærværende Omstaæding heder udi alle Provintzer, Stæder, Kirker, Slotte og Heeregaarde (-)
... / samlet og fortsat af Hans de Hofman (T. 7) (1)
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Effects of granular nematicides on the infection of potatoes by Rhizoctonia solani
No full textThe granular nematicides aldicarb, oxamyl and ethoprophos often are applied to control plant parasitic nematodes. However, the use of these pesticides may have some disadvantages. In field trials, they increased stem infection of potatoes caused by Rhizoctonia solani Kühn and incidence of black scurf (sclerotia of R. solani ) on tubers. This thesis, reports about possible mechanisms involved in the increased infection in nematicide treated fields. The effects of granular nematicides were studied on:- the pathogenicity of R. solani (Chapters 2 and 3)- the susceptibility of the host plant (Chapter 3)- the microbial antagonism to R. solani (Chapter 2)- the mycophagous soil fauna, i.e. nematodes (Chapters 5 and 7) or springtails and mites (Chapters 6 and 7)Ethoprophos was fungitoxic to R. solani . On Czapek Dox agar (CDA), the EC 50 of the compound was 49 mg l -1and at 100 mg l -1there was a total growth inhibition. Oxamyl showed a slight fungitoxicity. At 100 Mg 1-1 oxamyl in CDA, the growth of R. solani was reduced by 26 %. Aldicarb did not influence the growth of R. solani on CDA, but caused a slight growth stimulation on potato dextrose agar (PDA).The carbamate compounds aldicarb and oxamyl are systemically transported in plants. The presence inside the plant might, therefore, have some effect on the host-plant resistance to R. solani . The organophosphorus compound ethoprophos is not known to have a systemic activity, so it differs from the other two nematicides with respect to the uptake by the host plant. It was therefore, less likely that the increased infection by R. solani in nematicide-treated soil, was due to a reduced host-plant resistance. Laboratory experiments supplied the evidence that the nematicides did not reduce host-plant resistance.Ethoprophos caused an initial growth inhibition of potato sprouts, but immediately after their emergence, growth was promoted. In laboratory experiments carried out at 15 °C in a growth chamber, the emergence of sprouts was delayed by three days, when tubers were planted in ethoprophos-treated soil. However, most probably due to the fungitoxicity of ethoprophos, the appearance of lesions on the stems was delayed by nine days in this treatment. Oxamyl showed similar effects to ethoprophos, but to a lesser extent, while aldicarb did neither influence sprout development nor the appearance of lesions.The stages in the infection process, including growth of runner hyphae, branching of hyphae on the stem surface, formation of infection cushions and the relationship between size of the infection cushions and size of lesions, were not influenced by any of the nematicides.The previous observations made an indirect effect highly evident. In a study on the infection process was found that the size of lesions was proportional to the size of the infection cushions (dense masses of mycelium from which R. solani penetrates the plant). Any agent that changes the size of infection cushions will alter, therefore, the severity of the disease.By far the most important mycoparasite of R. solani in Dutch potato fields is Verticillium biguttatum , so the study on effects on mycoparasites was focussed on this fungus. The growth of V. biguttatum was strongly stimulated by aldicarb and ethoprophos on potato dextrose agar plates covered with mycelium of R. solani . The mechanism involved was not studied. In the nematicide-treated fields, the incidence of V. biguttatum on stolons was increased. This may be due to an increased availability of substrate (i.e. mycelium of R. solani ) or a reduced activity of the mycophagous soil fauna, as well as from a direct stimulation by the nematicide. At the recommended dosages of aldicarb, oxamyl or ethoprophos, an effect on soil fungistasis was not found, neither in laboratory experiments nor in field experiments.The laboratory experiments indicated that the most probable explanation for the increased disease severity of R. solani in nematicide-treated fields is a suppression of the mycophagous soil fauna. In the experimental fields, the most abundant mycophagous nematodes were Aphelenchus avenae and Aphelenchoides spp. These nematodes could be reared on petri-dishes covered with mycelium of R. solani . In the rhizosphere of plants of which the foliage was removed, numbers of A. avenae increased dramatically. Outside the rhizosphere, only very low numbers of A. avenae and Aphelenchoides spp. were found. It was assumed that the large increase was due to a rapid development of the microflora in the rhizosphere of dying roots. Aldicarb, oxamyl and ethoprophos greatly limited this increase.In a field that had been fumigated with dichloropropene, the granular nematicides hardly affected stem infection and black scurf incidence. Initially, metabolites that may have been formed after fumigation could have had a toxic effect on R. solani . All soil animals were strongly reduced at the beginning of the growing season in the fumigated field. Later in the season, numbers of A. avenae were much higher in the rhizosphere of plants grown in fumigated soil than in non-fumigated soil. Although the granular nematicides reduced numbers of A. avenae also in the fumigated soil, the remaining population density of A. avenae was still high. In nematicide-treated plots, the disease suppression was, therefore, not much lower than in the untreated plots.To simulate potato stems colonized by R. solani , flax straws colonized by the fungus were buried in the field. Mycophagous nematodes rapidly increased on the straws. In aldicarb-treated plots, only low numbers of mycophagous nematodes were observed on these straws. These data show that grazing of mycophagous nematodes on mycelium and probably also on infection cushions of R. solani will be less in nematicide-treated soil than in untreated soil.In one field trial, the effect of the insecticide lindane on R. solani was assessed to discriminate between the role of mycophagous nematodes and mycophagous microarthropods. In lindane-treated plots, stem infection and black scurf incidence were increased to almost the same extent as in aldicarb-treated plots. Lindane did not have any nematicidal activity. This indicates that at least in this field microarthropods may also reduce R. solani by grazing. Aldicarb, ethoprophos and lindane reduced the numbers of most springtails and mites in potato fields. The most abundant springtails were Tullbergia krausbaueri , Isotoma notabilis and Folsomia fimetaria , and the most abundant mites were Pygmephorus sellnicki , Pygmephorus blumentritti , Coccotydeus sp. and Histiosoma litorale . Numbers of Pygmephorus spp. were not reduced in aldicarb- and ethoprophos-treated plots. T. krausbaueri was reduced in lindaneand ethoprophos-treated plots, but only slightly in aldicarb- treated plots.In the laboratory, T. krausbaueri , F. fimetaria and H. litorale could be reared on petri-dishes covered with R. solani or cultures of R. solani in sterilized soil. Pygmephorus spp. and Coccotydeus sp. could not be reared on these cultures, while I. notabilis was not successfully isolated from the field. In laboratory experiments where the microarthropods were introduced in a soil inoculated with R. solani , T. krausbaueri and F. fimetaria caused a strong reduction of stem infection of potatoes. Lowest numbers of T. krausbaueri and F. fimetaria that significantly reduced disease severity were 9800 and 430 individuals per litre soil, respectively. H. litorale did not survive during the experiment, so it was probably not important in grazing on mycelium of R. solani . In similar inoculation experiments, A. avenae was also found to cause a significant reduction in stem infection when inoculated with 500 nematodes per litre. An Aphelenchoides sp. had no effect on stem infection. Nematodes reproduced within a few days at room temperature, while springtails and mites had a much slower reproduction cycle.A. avenae and F. fimetaria seem to be some of the most important mycophagous soil animals that lead to a reduction by R. solani in the field. A smaller contribution in the reduction of disease severity can be expected from T. krausbaueri and other mycophagous soil animals that are only present at low densities. However, some of the species that were not reared in the laboratory on mycelium of R. solani , may also be able to cause a significant reduction of disease severity at low population densities.Any pesticide that reduces the density of mycophagous soil animals will, therefore, facilitate a better development of R. solani . The stimulatory effects of granular nematicides on R. solani on potato seem primarily caused by reduced grazing of the mycophagous soil fauna on the pathogen in nematicide-treated fields.</TT
Letter, [Author unclear] to Paulina T. Merritt
No full textHandwritten letter to Paulina Merritt from an unknown author, October 1, 1876.
Geographic profiling in Nazi Berlin: fact and fiction
Get PDFGeographic profiling uses the locations of connected crime sites to make inferences about the probable location of the offender’s ‘anchor point’ (usually a home, but sometimes a workplace). We show how the basic ideas of the method were used in a Gestapo investigation that formed the basis of a classic German novel about domestic resistance to the Nazis during the Second World War. We use modern techniques to re-analyse this case, and show that these successfully locate the Berlin home address of Otto and Elise Hampel, who had distributed hundreds of anti-Nazi postcards, after analysing just 34 of the 214 incidents that took place before their arrest. Our study provides the first empirical evidence to support the suggestion that analysis of minor terrorism-related acts such as graffiti and theft could be used to help locate terrorist bases before more serious incidents occur
Den Danske Atlas Eller Konge-Riget Dannemark : Med dets Naturlige Egenskaber, Elementer, Indbyggere, Væxeter, Dyr og andre Affødninger, dets gamle Tildragelser og nærværende Omstaæding heder udi alle Provintzer, Stæder, Kirker, Slotte og Heeregaarde
No full textDEN DANSKE ATLAS ELLER KONGE-RIGET DANNEMARK : MED DETS NATURLIGE EGENSKABER, ELEMENTER, INDBYGGERE, VÆXETER, DYR OG ANDRE AFFØDNINGER, DETS GAMLE TILDRAGELSER OG NÆRVÆRENDE OMSTAÆDING HEDER UDI ALLE PROVINTZER, STÆDER, KIRKER, SLOTTE OG HEEREGAARDE
Den Danske Atlas Eller Konge-Riget Dannemark : Med dets Naturlige Egenskaber, Elementer, Indbyggere, Væxeter, Dyr og andre Affødninger, dets gamle Tildragelser og nærværende Omstaæding heder udi alle Provintzer, Stæder, Kirker, Slotte og Heeregaarde
... / samlet og fortsat af Hans de Hofman (T. 7) (1
Integrated design for a CVT: dynamical optimization of actuation and control
Get PDFWith increasing demands on more energy and fuel efficient vehicles, one can achieve the goal by improving the vehicle powertrain system. A continuously variable transmission (CVT) allows the engine or electric machine to operate on its optimal operation points. The optimal operation points are high efficiency points that lead to reduced energy consumption of the vehicle. However, this type of transmission may still have relatively high actuation losses (depending on the actuation type), which hinders the energy saving benefits. Classically, the plant (e.g., actuation system, variator) of the CVT was separately designed from the control design. In this paper, an integrated optimal CVT variator and actuation control design is presented. The aim of the new design is to minimize the CVT mass (pulley sheaves, belt), tracking error and control effort. To achieve this goal, a nested optimization framework is implemented to obtain an optimal transmission system design over a selected drive cycle. The results show that the optimized CVT design yields non-compromising tracking performance, however, with much smaller variator mass (-46%) and control effort (-62%)
Handwritten biographical information on Paulina T. McClung Merritt
No full textA handwritten biography of Paulina T. McClung Merritt by an unknown author, 1892.
Heterogeneous and tissue-specific regulation of effector T cell responses by IFN-gamma during Plasmodium berghei ANKA infection.
Get PDFIFN-γ and T cells are both required for the development of experimental cerebral malaria during Plasmodium berghei ANKA infection. Surprisingly, however, the role of IFN-γ in shaping the effector CD4(+) and CD8(+) T cell response during this infection has not been examined in detail. To address this, we have compared the effector T cell responses in wild-type and IFN-γ(-/-) mice during P. berghei ANKA infection. The expansion of splenic CD4(+) and CD8(+) T cells during P. berghei ANKA infection was unaffected by the absence of IFN-γ, but the contraction phase of the T cell response was significantly attenuated. Splenic T cell activation and effector function were essentially normal in IFN-γ(-/-) mice; however, the migration to, and accumulation of, effector CD4(+) and CD8(+) T cells in the lung, liver, and brain was altered in IFN-γ(-/-) mice. Interestingly, activation and accumulation of T cells in various nonlymphoid organs was differently affected by lack of IFN-γ, suggesting that IFN-γ influences T cell effector function to varying levels in different anatomical locations. Importantly, control of splenic T cell numbers during P. berghei ANKA infection depended on active IFN-γ-dependent environmental signals--leading to T cell apoptosis--rather than upon intrinsic alterations in T cell programming. To our knowledge, this is the first study to fully investigate the role of IFN-γ in modulating T cell function during P. berghei ANKA infection and reveals that IFN-γ is required for efficient contraction of the pool of activated T cells
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Pelevin’s Trinity in the novel “t”: author – protagonist – reader
No full textThe article attempts to interpret Pelevin's artistic strategy in the novel "T" by exploring its subject organization and addressing the key problems of the author, the protagonist, and the reader as they are seen by the researcher. The article analyzes the peculiarities of constructing the narrative reality in the novel "T", and goes on to discuss Pelevin's philosophic models of the development of the humankind, and the emergence of his new anthropology
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