Mayenne is a department in northwest France named after the Mayenne River. Mayenne is part of the current region of Pays de la Loire and is surrounded by the departments of Manche, Sarthe, Maine-et-Loire, Ille-et-Vilaine. Mayenne is one of the original 83 departments created during the French Revolution on March 4, 1790; the northern two thirds correspond to the western part of the former province of Maine. The southern third of Mayenne corresponds to the northern portion of the old province of Anjou; the inhabitants of the department are called Mayennais. Like 82 other departments, Mayenne was created on March 4, 1790 during the early stages of the French Revolution by order of the National Constituent Assembly; the new departments were to be uniformly administered and equal to one another in size and population. The former province of Maine was partitioned into two, Upper Maine, centred on Le Mans, became the new department of Sarthe, Lower Maine, centred on Laval became the new department of Mayenne.

Anjou, to the south, being too big to form a single department, was reduced in size and became Maine-et-Loire. In this partition, Sarthe received the region of La Flèche, Mayenne received Château-Gontier and Craon. Flax was a feature of the Mayenne economy, the southern limit for the cultivation of flax was used to determine the new border between Mayenne and Maine-et-Loire. Mayenne is part of the region of Pays de la Loire; the department does not have a sea coast, but about thirty kilometres to the northwest is Mont Saint-Michel Bay. The capital and largest town is Laval in the centre of the department. To the north lies the department of Orne, to the east lies Sarthe, to the south lies Maine-et-Loire, to the west lies Ille-et-Vilaine and to the northwest lies Manche; the department forms a rectangular shape, being 90 km long by 77 km wide, with a total area of about 5,175 km2. The River Mayenne flows centrally through it from north to south, passing through the towns of Mayenne, Laval and Château-Gontier.

After leaving the department, the river joins the River Sarthe to form the River Maine which joins the River Loire. The department is varied in topography. Much of it is flat, but there are hilly areas, some with steep-sided valleys and ravines. Of the total area of 1,275,532 acres, some 875,000 acres are arable, 170,000 acres are grassland, 65,000 acres are forests and woodland and 50,000 acres are heathland and moorland. To the north lies the Armorican Massif, a plateau, eroded over time, the highest summit of which, the Mont des Avaloirs, is the highest point in the department at 417 m above sea level. A branch range to the south of this plateau forms the ridge that divides the Mayenne Valley from the Vilaine Valley; the department is subdivided into three arrondissements: Mayenne, Château-Gontier. Population development since 1801: Mayenne has a diversity of habitat types such as forest, heathland and farmland; some 1445 species of plants, 63 species of mammals, 280 species of birds, 16 species of amphibians and 11 species of reptiles have been recorded, as well as thousands of species of invertebrates.

The peat-lands and bogs are fringed with woodlands of alder and ash, in some places carnivorous plants such as sundew and butterwort flourish, marsh cinquefoil and cottongrass grow and butterflies and spiders abound. The woodlands are small with the deciduous trees dominated by oak. Here roe deer, fire salamander, Aesculapian snake, middle spotted woodpecker, little owl and white admiral can be found and uncommon plants present including European columbine and wild russet apple; the dry grasslands, which cover the limestone and sandstone soils, are rich in fauna and flora. They house the snake Vipera aspis, the large blue butterfly, the blue-winged grasshopper and the bee orchid; the heathland in the north of Mayenne is populated by dwarf gorse and cross-leaved heath and there are plenty of spiders and warblers. The old quarries are the refuge of bats, the shining cranesbill and greater butterfly orchid. Rivers and ponds are home to eel, northern crested newt, European otter, grass snake, common moorhen and plants such as spearwort, yellow flag and Isopyrum thalictroides, a small poisonous plant.

The department is rural with about 80% being used for agriculture, 8% being urban area and the remainder forest and plantations. Livestock farming predominates, with the breeding of cattle and pigs, bee-keeping being important; the soil is poor, but it is of better quality around Laval and Château-Gontier. In these parts corn is cultivated and there are plantings of hemp, flax and vines. There are many apple orchards and large quantities of cider are made; the department is rich in mineral resources. Industries include the manufacture of linen and hemp, cider-making is traditionally carried on in the department. Office furniture is manufactured in Château-Gontier, Laval is active in the industrial sector, with dairy products and chemicals in a modern science park. Cantons of the Mayenne department Communes of the Mayenne department Arrondissements of the Mayenne department Duke of Mayenne Prefecture website General council website

Karl, Freiherr von Prel

Karl Ludwig August Friedrich Maximilian Alfred, Freiherr von Prel, or, in French, Carl Ludwig August Friedrich Maximilian Alfred, Baron du Prel, was a German philosopher and writer on mysticism and the occult. In the literature it has become customary to refer to him under various abbreviated French forms of his name "Carl Du Prel," "Baron Carl Du Prel," or "Baron Du Prel." He was born at Landshut. After studying at the University of Munich he served in the Bavarian army from 1859 to 1872, when he retired with the rank of captain, he gave himself up to philosophical work in connection with the phenomena of hypnotism and occultism from the modern psychological standpoint. He attempted to deduce the existence of spirit, apart from, yet entering from time to time into connection with, the phenomena of the senses, by an examination of the relation between the ego of thought and the age of sensible experience as understood by Immanuel Kant. In 1868 he received the degree of doctor from the University of Tübingen in recognition of a treatise on the psychology of dreams.

Du Prel sought to combine early parapsychological research and Kantian transcendental idealism to argue that mystical experiences were universal and subjective, paralleling a similar argument made by William James. Subsequently, he published numerous works on various psychological and scientific subjects, of which the more important are: Der gesunde Menschenverstand vor den Problemen der Wissenschaft. In Der Kampf ums Dasein am Himmel, von Prel endeavoured to apply the Darwinian doctrine of biological evolution not only to the sphere of consciousness but even more as the philosophical principle of the world, he was one of a large number of German thinkers who, during the latter half of the nineteenth century, endeavored to treat the mind as a mechanism. His interest in Darwinism was tied to a belief in extraterrestrial life. Although today regarded as an obscure figure in the history of occultism, in his own lifetime du Prel was respected as a scientist and philosopher; the fourth edition of Sigmund Freud's The Interpretation of Dreams positively cites du Prel as both a mystic and one whose conclusions parallel and apply Freud's work.

This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed.. "Prel, Freiherr von". Encyclopædia Britannica. 22. Cambridge University Press. Pp. 277–278. Josephson, Jason Ānanda. "Specters of Reason: Kantian Things and the Fragile Terrors of Philosophy" J19, Volume 3, Number1, Spring 2015, pp. 204–211. Josephson-Storm, Jason; the Myth of Disenchantment: Magic and the Birth of the Human Sciences. Chicago: University of Chicago Press. ISBN 978-0-226-40336-6.</ref> Weber, Thomas P.. "Carl du Prel: explorer of dreams, the soul, the cosmos". Studies in History and Philosophy of Science Part A. 38: 593–604. Doi:10.1016/j.shpsa.2007.06.005

Sigma factor

A sigma factor is a protein needed for initiation of transcription in bacteria. It is a bacterial transcription initiation factor that enables specific binding of RNA polymerase to gene promoters, it is homologous to archaeal transcription factor B and to eukaryotic factor TFIIB. The specific sigma factor used to initiate transcription of a given gene will vary, depending on the gene and on the environmental signals needed to initiate transcription of that gene. Selection of promoters by RNA polymerase is dependent on the sigma factor that associates with it, they are found in plant chloroplasts as a part of the bacteria-like plastid-encoded polymerase. The sigma factor, together with RNA polymerase, is known as the RNA polymerase holoenzyme; every molecule of RNA polymerase holoenzyme contains one sigma factor subunit, which in the model bacterium Escherichia coli is one of those listed below. The number of sigma factors varies between bacterial species. E. coli has seven sigma factors. Sigma factors are distinguished by their characteristic molecular weights.

For example, σ70 is the sigma factor with a molecular weight of 70 kDa. The sigma factor in the RNA polymerase holoenzyme complex is required for the initiation of transcription, although once that stage is finished, it is dissociated from the complex and the RNAP continues elongation on its own. Different sigma factors are utilized under different environmental conditions; these specialized sigma factors bind the promoters of genes appropriate to the environmental conditions, increasing the transcription of those genes. Sigma factors in E. coli: σ70 – σA – the "housekeeping" sigma factor or called as primary sigma factor, transcribes most genes in growing cells. Every cell has a "housekeeping" sigma factor that pathways operating. In the case of E. coli and other gram-negative rod-shaped bacteria, the "housekeeping" sigma factor is σ70. Genes recognized by σ70 all contain similar promoter consensus sequences consisting of two parts. Relative to the DNA base corresponding to the start of the RNA transcript, the consensus promoter sequences are characteristically centered at 10 and 35 nucleotides before the start of transcription.

Σ19 – the ferric citrate sigma factor, regulates the fec gene for iron transport and metabolism σ24 – extreme heat stress response and the extracellular proteins sigma factor σ28 – the flagellar synthesis and chemotaxis sigma factor σ32 – the heat shock sigma factor, it is turned on when the bacteria are exposed to heat. Due to the higher expression, the factor will bind with a high probability to the polymerase-core-enzyme. Doing so, other heatshock proteins are expressed, which enable the cell to survive higher temperatures; some of the enzymes that are expressed upon activation of σ32 are chaperones, proteases and DNA-repair enzymes. Σ38 – the starvation/stationary phase sigma factor σ54 – the nitrogen-limitation sigma factorThere are anti-sigma factors that inhibit the function of sigma factors and anti-anti-sigma factors that restore sigma factor function. By sequence similarity, most sigma factors are σ70-like, they have four main regions that are conserved: N-terminus --------------------- C-terminus 1.1 2 3 4 The regions are further subdivided.

For example, region 2 includes 1.2 and 2.1 through 2.4. Domain 1.1 is found only in "primary sigma factors". It is involved in ensuring the sigma factor will only bind the promoter when it is complexed with the RNA polymerase. Domains 2-4 each interact with specific promoter elements and with RNAP. Region 2.4 recognizes and binds to the promoter −10 element. Region 4.2 binds to the promoter − 35 element. Not every sigma factor of the σ70 family contains all the domains. Group 2, which includes RpoS, is similar to Group 1 but lacks domain 1. Group 3 lacks domain 1, includes σ28. Group 4 known as the Extracytoplasmic Function group, lack both σ1.1 and σ3. RpoE is a member. Other known sigma factors are of the σ54/RpoN type, they are functional sigma factors, but they have different primary amino acid sequences. The core RNA polymerase binds a sigma factor to form a complex called the RNA polymerase holoenzyme, it was believed that the RNA polymerase holoenzyme initiates transcription, while the core RNA polymerase alone synthesizes RNA.

Thus, the accepted view was that sigma factor must dissociate upon transition from transcription initiation to transcription elongation. This view was based on analysis of purified complexes of RNA polymerase stalled at initiation and at elongation. Structural models of RNA polymerase complexes predict that, as the growing RNA product becomes longer than ~15 nucleotides, sigma must be "pushed out" of the holoenzyme, since there is a steric clash between RNA and a sigma domain. However, a recent study has shown that σ70 can remain attached in complex with the core RNA polymerase, at least during early elongation. Indeed, the phenomenon of promoter-proximal pausing indicates that sigma plays roles during early elongation. All studies are consistent with the assumption that promoter escape reduces the lifetime of the sigma-core interaction from long at initiation to a shorter, measurable lifetime upon transition to elongation, it long has been thought that the sigma factor obligatorily leaves the core enzyme once it has initiated transcription, al