La genèse de The Souls of Black Folk : le chapitre initial de la vie intellectuelle de W. E. B. Du Bois, 1885-1903

En 1903, paraît le magnum opus de William Edward Burghardt Du Bois, The Souls of Black Folk. Ce dernier écrit cet ouvrage en poursuivant trois objectifs. Primo, il souhaite démontrer que Booker T. Washington et ses supporters font fausse route en défendant l’idée selon laquelle les Afro-américains pourront accéder à un avenir meilleur en échangeant leurs droits politiques contre des opportunités économiques. Secundo, Du Bois cherche à faire la lumière sur les talents distinctifs et les grandes réalisations de son peuple afin de convaincre les Blancs que les Noirs ne leur sont pas biologiquement ou moralement inférieurs et, par conséquent, que l’égalité raciale doit être totale et immédiate. Tertio, il veut persuader les Américains de devenir de meilleurs citoyens, en renouant avec les idéaux de leur République et en vivant en fonction de principes moraux élevés. L’écriture de Souls marque un tournant majeur dans la vie intellectuelle de son auteur, car il renonce à cette époque au discours conciliatoire qu’il avait tenu dans sa jeunesse. Les idées qu’il défend dans son livre ont germé quelques années plus tôt, au contact de certains de ses professeurs de l’Université de Berlin, d’Alexander Crummell et surtout, en effectuant une étude de terrain sur la communauté noire de Philadelphie. Du Bois réalise alors l’ampleur des injustices dont sont victimes les Noirs et contre lesquelles la bonne volonté et le travail acharné ne peuvent rien.

The souls of black folk : essays and sketches /

Of our spiritual strivings -- Of the dawn of freedom -- Of Mr. Booker T. Washington and others -- Of the meaning of progress -- Of the wings of Atalanta -- Of the training of black men -- Of the black belt -- Of the quest of the golden fleece -- Of the sons of master and man -- Of the faith of the fathers -- Of the passing of the first-born -- Of Alexander Crummell -- Of the coming of John -- The sorrow songs.

The souls of black folk : essays and sketches /

Mode of access: Internet.

The gift of black folk; the Negroes in the making of America,

Mode of access: Internet.

The souls of the black folk: essays and sketches,

Photocopy.

The Role of Black Rice (Oryza sativa L.) in the Control of Hypercholesterolemia in Rats

Cardiovascular disease is a serious public health problem; it is the first cause of death in Brazil and in developed countries. Thus, it is essential to search for alternative sources such as some functional foods to prevent and control the risks of this disease. The purpose of this study was to evaluate the lipidemic parameters in hypercholesterolemic rats fed diets containing black rice variety IAC 600 or unrefined rice. Adult male Wistar rats (Rattus norvegicus var. albinos) were used, weighing about 200-220 g. The animals were divided into four groups: the first received a control casein diet, the second received hypercholesterolemic diet, and the other two groups, after induction of hypercholesterolemia, received the test diets, the first containing 20% black rice and the second 20% unrefined, for 30 days. It was observed that diet containing black rice reduced the level of plasma cholesterol, triglycerides, and low-density lipoprotein. For high-density lipoprotein values, the diet that provided an increase in the levels was the black rice. The diet containing black rice was more effective in controlling the lipidemia in rats compared with the whole rice diet.

The origin of black colouration in onyx agate from Mali

Natural onyx agate from Mali was investigated in an integrated mineralogical and chemical study to reveal the origin of the unusual black colouration. Detailed studies by polarizing microscopy, scanning electron microscopy and micro-Raman spectroscopy showed that the colour of the dark bands is related to the incorporation of small particles of carbon (low-crystalline graphite) up to 200 nm in size into the cryptocrystalline silica matrix. The dark bands have carbon contents of 1.88 wt.%. The location of the graphite particles is closely related to the primary structural banding in the chalcedony. Cathodoluminescence data shows that the banding is interrupted by small fissures containing secondary hydrothermal quartz. The carbon isotope composition (delta C-13 value of -31.1+/-0.2 parts per thousand) of the carbonaceous material points to an organic precursor. Both the direct hydrothermal formation of graphite from methane under elevated temperature and the graphitization of organic precursors by secondary hydrothermal or metamorphic overprint are possible explanations for the colour of the dark bands. The graphitization of organic precursors results in an intense electron spin resonance line at g(eff) = 2.0026.

Statistical evaluation of the reproducibility and the influence of paper on the analysis of black gel pen ink using laser desorption ionisation mass spectrometry

Laser desorption ionisation mass spectrometry (LDI-MS) has demonstrated to be an excellent analytical method for the forensic analysis of inks on a questioned document. The ink can be analysed directly on its substrate (paper) and hence offers a fast method of analysis as sample preparation is kept to a minimum and more importantly, damage to the document is minimised. LDI-MS has also previously been reported to provide a high power of discrimination in the statistical comparison of ink samples and has the potential to be introduced as part of routine ink analysis. This paper looks into the methodology further and evaluates statistically the reproducibility and the influence of paper on black gel pen ink LDI-MS spectra; by comparing spectra of three different black gel pen inks on three different paper substrates. Although generally minimal, the influences of sample homogeneity and paper type were found to be sample dependent. This should be taken into account to avoid the risk of false differentiation of black gel pen ink samples. Other statistical approaches such as principal component analysis (PCA) proved to be a good alternative to correlation coefficients for the comparison of whole mass spectra.

An investigative study on the effects of black fly (diptera: simuliidae) sugar meals on reproductive success and parasite transmission /

Black flies are opportunistic sugar-feeders. They take sugar meals from Homopteran honeydew secretions or plant nectars, depending on availability. Homopteran honeydew secretions contain both simple and complex carbohydrates while plant nectars contain primarily simple carbohydrates. In order to determine whether honeydew secretions offer more energy than plant nectars to their insect visitors a study of wild-caught black flies was undertaken in Algonquin Provincial Park, Canada during the spring of 1 998 and 1 999. It was hypothesized that female black flies maintained on honeydew sugars will survive longer, produce more eggs and have a greater parasite vectoring potential than those maintained on artificial nectar or distilled water. Results demonstrated that: (1) host-seeking female Prosimulimfuscum/mixtum and Simulium venustum maintained on artificial honeydew did not survive longer than those maintained on artificial nectar when fed ad libitum; (2) fiiUy engorged S. venustum and Simulium rugglesi maintained on artificial honeydew did not produce more eggs than those maintained on artificial nectar when fed ad libitum; and (3) S. rugglesi did not have a greater vectoring potential of Leucocytozoon simondi when maintained on artificial honeydew as opposed to artificial nectar when fed ad libitum. However, all flies maintained on the two sugars (artificial honeydew and artificial nectar) survived longer, produce more eggs and had greater vectoring potential than those maintained on distilled water alone.

Corynebacterium ciconiae sp. nov., isolated from the trachea of black storks (Ciconia nigra)

SEight unidentified Gram-positive, rod-shaped organisms were recovered from the tracheas of apparently healthy black storks (Ciconia nigra) and subjected to a polyphasic taxonomic analysis. Based on cellular morphology and biochemical criteria the isolates were tentatively assigned to the genus Corynebacterium, although three of the organisms did not appear to correspond to any recognized species. Comparative 16S rRNA gene sequencing studies demonstrated that all of the isolates were phylogenetically members of the genus Corynebacterium. Five strains were genotypically identified as representing Corynebacterium falsenii, whereas the remaining three strains represented a hitherto unknown subline, associated with a small subcluster of species that includes Corynebacterium mastitidis and its close relatives. On the basis of phenotypic and phylogenetic evidence, it is proposed that the unknown isolates from black storks represent a novel species within the genus Corynebacterium, for which the Corynebacterium ciconiae sp. nov. is proposed. The type strain is CECT 5779(T) (= BS13(T) =CCILIG 47525(T)).

Bounding the role of black carbon in the climate system: a scientific assessment

Black carbon aerosol plays a unique and important role in Earth’s climate system. Black carbon is a type of carbonaceous material with a unique combination of physical properties. This assessment provides an evaluation of black-carbon climate forcing that is comprehensive in its inclusion of all known and relevant processes and that is quantitative in providing best estimates and uncertainties of the main forcing terms: direct solar absorption; influence on liquid, mixed phase, and ice clouds; and deposition on snow and ice. These effects are calculated with climate models, but when possible, they are evaluated with both microphysical measurements and field observations. Predominant sources are combustion related, namely, fossil fuels for transportation, solid fuels for industrial and residential uses, and open burning of biomass. Total global emissions of black carbon using bottom-up inventory methods are 7500 Gg yr�-1 in the year 2000 with an uncertainty range of 2000 to 29000. However, global atmospheric absorption attributable to black carbon is too low in many models and should be increased by a factor of almost 3. After this scaling, the best estimate for the industrial-era (1750 to 2005) direct radiative forcing of atmospheric black carbon is +0.71 W m�-2 with 90% uncertainty bounds of (+0.08, +1.27)Wm�-2. Total direct forcing by all black carbon sources, without subtracting the preindustrial background, is estimated as +0.88 (+0.17, +1.48) W m�-2. Direct radiative forcing alone does not capture important rapid adjustment mechanisms. A framework is described and used for quantifying climate forcings, including rapid adjustments. The best estimate of industrial-era climate forcing of black carbon through all forcing mechanisms, including clouds and cryosphere forcing, is +1.1 W m�-2 with 90% uncertainty bounds of +0.17 to +2.1 W m�-2. Thus, there is a very high probability that black carbon emissions, independent of co-emitted species, have a positive forcing and warm the climate. We estimate that black carbon, with a total climate forcing of +1.1 W m�-2, is the second most important human emission in terms of its climate forcing in the present-day atmosphere; only carbon dioxide is estimated to have a greater forcing. Sources that emit black carbon also emit other short-lived species that may either cool or warm climate. Climate forcings from co-emitted species are estimated and used in the framework described herein. When the principal effects of short-lived co-emissions, including cooling agents such as sulfur dioxide, are included in net forcing, energy-related sources (fossil fuel and biofuel) have an industrial-era climate forcing of +0.22 (�-0.50 to +1.08) W m-�2 during the first year after emission. For a few of these sources, such as diesel engines and possibly residential biofuels, warming is strong enough that eliminating all short-lived emissions from these sources would reduce net climate forcing (i.e., produce cooling). When open burning emissions, which emit high levels of organic matter, are included in the total, the best estimate of net industrial-era climate forcing by all short-lived species from black-carbon-rich sources becomes slightly negative (�-0.06 W m�-2 with 90% uncertainty bounds of �-1.45 to +1.29 W m�-2). The uncertainties in net climate forcing from black-carbon-rich sources are substantial, largely due to lack of knowledge about cloud interactions with both black carbon and co-emitted organic carbon. In prioritizing potential black-carbon mitigation actions, non-science factors, such as technical feasibility, costs, policy design, and implementation feasibility play important roles. The major sources of black carbon are presently in different stages with regard to the feasibility for near-term mitigation. This assessment, by evaluating the large number and complexity of the associated physical and radiative processes in black-carbon climate forcing, sets a baseline from which to improve future climate forcing estimates.