2,784 research outputs found

    Dramatic Battles in Eighteenth-Century France: Philosophes, Anti-philosophes, and Polemical Theatre

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    Traditionally, the essay contest has occupied a relatively minor place in histories of the Enlightenment public sphere, discussion of its contribution to the intellectual and literary life of eighteenth-century France being largely limited to passing references in descriptions of the parent Academies. Jeremy Caradonna aims to rehabilitate the role of the essay contest, elucidating its distinctive contribution to Enlightenment practice and arguing that it provides an important new outlook on the contemporary public sphere

    Magnetic influence on the frequency of the soft-phonon mode in the incipient ferroelectric EuTiO3

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    The dielectric constant of the incipient ferroelectric EuTiO3_3 exhibits a sharp decrease at about 5.5K, at which temperature antiferromagnetic ordering of the Eu spins simultaneously appears, indicating coupling between the magnetism and dielectric properties. This may be attributed to the modification of the soft-phonon mode, T1ÎŒT_{1\mu}, which is the main contribution to the large dielectric constant, by the Eu spins(7ÎŒB\mu_B per Eu). By adding the coupling term between the magnetic and electrical subsystems as −g∑l∑<i,jql2Si→⋅Sj→ -g\sum\limits_l {\sum\limits_{< {i,j}} {q_l^2}} \overrightarrow {S_i} \cdot \overrightarrow {S_j} we show that the variation of the frequency of soft-phonon mode depends on the spin correlation between the nearest neighbors Eu spins and is substantially changed under a magnetic field.Comment: 13 pages, 4 figure

    Probing Plasmodium falciparum sexual commitment at the single-cell level

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    Background: Malaria parasites go through major transitions during their complex life cycle, yet the underlying differentiation pathways remain obscure. Here we apply single cell transcriptomics to unravel the program inducing sexual differentiation in Plasmodium falciparum. Parasites have to make this essential life-cycle decision in preparation for human-to-mosquito transmission. Methods: By combining transcriptional profiling with quantitative imaging and genetics, we defined a transcriptional signature in sexually committed cells. Results: We found this transcriptional signature to be distinct from general changes in parasite metabolism that can be observed in response to commitment-inducing conditions. Conclusions: This proof-of-concept study provides a template to capture transcriptional diversity in parasite populations containing complex mixtures of different life-cycle stages and developmental programs, with important implications for our understanding of parasite biology and the ongoing malaria elimination campaign

    Epidemiological surveys of camel trypanosomosis in Al-jouf, Saudi Arabia based on PCR and ELISA

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    Trypanosomosis due to Trypanosoma evansi (surra) is a major enzootic disease of the dromedary camel. The present study was conducted to determine the prevalence of camel trypanosomosis in the northern part of Saudi Arabia with different methods of diagnosis (ELISA, PCR) and to compare the results to whose obtained previously with Card Agglutination Test for Trypanosomiasis (CATT/T.evansi). A total of 195 blood samples and 118 serum samples were used for molecular and serological investigation respectively. After analyses, 25% (49/195) and 3% (4/118) samples were positive using PCR and ELISA respectively. The variability of trypanosomosis was highly significant to the factor moving, location, breed and clinical signs with PCR. The discrepancy between PCR, CATT test and ELISA is likely due to antibodies degradation on spotted papers maintained several weeks at ambient temperature. This is the first molecular diagnosis report which gives a picture of camel trypanosomosis in Al-jouf, Saudi Arabia

    Fast pyrolysis bio-oil production in an entrained flow reactor pilot

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    Bio-oil produced from biomass fast pyrolysis could constitute an alternative to fossil liquid fuels, especially to be combusted for local district heating. So far, only few studies have dealt with bio-oil production by biomass fast pyrolysis in an entrained flow reactor [1], yet it could constitute an alternative to the better-known fluidised bed pyrolysis process. In the context of the BOIL project with the CCIAG Company (Grenoble district heating), a new pilot based on an entrained flow reactor concept has been designed [2]. The pilot design has been carried out on the basis of woody biomass fast pyrolysis experiments and modeling performed in a drop tube reactor as a first step laboratory-scale study, and also CFD modeling [2-3]. The facility is composed of a biomass injection system with a hopper and a feeding screw, an electrically heated pyrolysis reactor, a cyclone to separate gas and char, 3 heat exchangers to cool the gas (at 30°C, 0°C and 0°C respectively) and condense bio-oil, and a post-combustion unit to burn the incondensable species. Gas temperature is maintained at 350°C from the reactor outlet to the entrance of the first heat exchanger in order to avoid bio-oil condensation. Several conditions were tested in 14 runs: 3 different biomass feedstocks, varying biomass feeding rates from 2 to 9 kg/h and two reactor temperatures 500°C and 550°C. 85 kg of bio-oil has been produced for combustion tests. Recovered bio-oil mass yield is on average 50%, its LHV is about 15 MJ/kg, its water content 26%w and its pH 2.15. We identified three main difficulties during the runs: about 15% of the bio-oil go through the heat exchanger, some char particles go through the cyclone which causes regular plugging of the first heat exchanger. Detailed analyses of the bio-oil produced have been done and the chemical and physical bio-oil characteristics have been compared to the European Standard recommendations [4]. With a regularly cleaning of the first heat exchanger, we successfully produce bio-oil with physical and chemical properties in agreement with the European Standard recommendations. Combustion tests of the bio-oil produced have been carried on by the CIRAD. They succeeded in obtaining a stable flame (without the use of a pilot flame) in a 50 kW burner and a 250 kW combustion chamber. However the physical and chemical characteristics of the bio-oil involve the use of specific pump and pulverization system adapted. In perspective for future projects, it would be interesting to perform pilot modifications in order to increase bio-oil yield and to minimize heat exchanger cleaning, and to test other resources like agricultural biomass or solid recovered fuels. Bibliography 1. J.A. Knight, C.W. Gorton, R.J. Kovac, Biomass 6, pp. 69-76, 1984. 2. Fast pyrolysis reactor for organic biomass materials with against flow injection of hot gases - US 20170166818 A1 3. Guizani, S.Valin, J.Billlaud, M.Peyrot, S.Salvador, Fuel, 2017, 207, pp.71-84. 4. C.Guizani, S.Valin, M.Peyrot, G.Ratel S.Salvador, Woody biomass fast pyrolysis in a drop tube reactor - Pyro2016 conference 5. Fast pyrolysis bio-oils for industrial boilers – Requirements and test methods – EN 1690

    Solid-phase phosphorus speciation in Saharan Bodélé depression dusts and source sediments

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    Phosphorus (P) is one of the most important limiting nutrients for the growth of oceanic phytoplankton and terrestrial ecosystems, which in turn contributes to CO2 sequestration. The solid-phase speciation of P will influence its solubility and hence its availability to such ecosystems. This study reports on the results of X-ray diffraction, electron microprobe chemical analysis and X-ray mapping, chemical extractions and X-ray absorption near-edge spectroscopy analysis carried out to determine the solid-phase speciation of P in dusts and their source sediments from the Saharan BodĂ©lĂ© Depression, the world’s largest single source of dust. Chemical extraction data suggest that the BodĂ©lĂ© dusts contain 28 to 60% (mean 49%) P sorbed to, or co-precipitated with Fe (hydr)oxides, < 10% organic P, 21-50% (mean 32%) detrital apatite P, and 10-22% (mean 15%) authigenic-biogenic apatite P. This is confirmed by the other analyses, which also suggest that the authigenic-biogenic apatite P is likely fish bone and scale, and that this might form a larger proportion of the apatite pool (33 +/− 22%) than given by the extraction data. This is the first-ever report of fish material in aeolian dust, and it is significant because P derived from fish bone and scale is relatively soluble and is often used as a soil fertilizer. Therefore, the fish-P will likely be the most readily form of BodĂ©lĂ© P consumed during soil weathering and atmospheric processing, but given time and acid dissolution, the detrital apatite, Fe-P and organic-P will also be made available. The BodĂ©lĂ© dust input of P to global ecosystems will only have a limited life, however, because its major source materials, diatomite in the BodĂ©lĂ© Depression, undergo persistent deflation and have a finite thickness
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