Nombre chromosomique d’angiospermes marocaines

Le nombre chromosomique de douze taxa appartenant à onze familles d’angiospermes marocaines sont rapportés: Achyranthes sicula n = 40; Bidens pilosa 2n = 60 et n = 30; Carrichtera annua 2n = 16; Clematis cirrhosa 2n = 16; Eryngium atlanticum n = 8; Parietaria judaica n = 13; Parietaria lusitanica subsp. lusitanica n = 10;  Scrofularia canina 2n = 24; Sixalix atropurpurea 2n = 16; Solanum sodomaeum n = 12;  Spergularia diandra 2n = 18 et Urginea maritima n = 30. La plus part des ces nombres sont rapportés pour la première fois sur des populations marocaines. Des microphotographies mitotiques ou méiotiques ainsi qu’un bref commentaire sont signalés pour chaque taxon.Chromosome numbers of twelve taxa from eleven families of Moroccan angiosperms are reported: Achyranthes sicula n = 40; Bidens pilosa 2n = 60 et n = 30;  Carrichtera annua 2n = 16; Clematis cirrhosa 2n = 16; Eryngium atlanticum n = 8; Parietaria judaica n = 13; Parietaria lusitanica subsp. lusitanica n = 10;  Scrofularia canina 2n = 24; Sixalix atropurpurea 2n = 16; Solanum sodomaeum n = 12;  Spergularia diandra 2n = 18 and Urginea maritima n = 30. Most of those numbers were reported for the fi rst time in Moroccan populations. Mitotic or meiotic metaphases microphotographs and brief comments are detailed for each taxa studied

Electrostatic and electrokinetic contributions to the elastic moduli of a driven membrane

We discuss the electrostatic contribution to the elastic moduli of a cell or artificial membrane placed in an electrolyte and driven by a DC electric field. The field drives ion currents across the membrane, through specific channels, pumps or natural pores. In steady state, charges accumulate in the Debye layers close to the membrane, modifying the membrane elastic moduli. We first study a model of a membrane of zero thickness, later generalizing this treatment to allow for a finite thickness and finite dielectric constant. Our results clarify and extend the results presented in [D. Lacoste, M. Cosentino Lagomarsino, and J. F. Joanny, Europhys. Lett., {\bf 77}, 18006 (2007)], by providing a physical explanation for a destabilizing term proportional to \kps^3 in the fluctuation spectrum, which we relate to a nonlinear ($E^2$) electro-kinetic effect called induced-charge electro-osmosis (ICEO). Recent studies of ICEO have focused on electrodes and polarizable particles, where an applied bulk field is perturbed by capacitive charging of the double layer and drives flow along the field axis toward surface protrusions; in contrast, we predict "reverse" ICEO flows around driven membranes, due to curvature-induced tangential fields within a non-equilibrium double layer, which hydrodynamically enhance protrusions. We also consider the effect of incorporating the dynamics of a spatially dependent concentration field for the ion channels.Comment: 22 pages, 10 figures. Under review for EPJ

The neurology of COVID-19 revisited: A proposal from the environmental neurology specialty group of the world federation of neurology to implement international neurological registries

A comprehensive review of the neurological disorders reported during the current COVID-19 pandemic demonstrates that infection with SARS-CoV-2 affects the central nervous system (CNS), the peripheral nervous system (PNS) and the muscle. CNS manifestations include: headache and decreased responsiveness considered initial indicators of potential neurological involvement; anosmia, hyposmia, hypogeusia, and dysgeusia are frequent early symptoms of coronavirus infection. Respiratory failure, the lethal manifestation of COVID-19, responsible for 264,679 deaths worldwide, is probably neurogenic in origin and may result from the viral invasion of cranial nerve I, progressing into rhinencephalon and brainstem respiratory centers. Cerebrovascular disease, in particular large-vessel ischemic strokes, and less frequently cerebral venous thrombosis, intracerebral hemorrhage and subarachnoid hemorrhage, usually occur as part of a thrombotic state induced by viral attachment to ACE2 receptors in endothelium causing widespread endotheliitis, coagulopathy, arterial and venous thromboses. Acute hemorrhagic necrotizing encephalopathy is associated to the cytokine storm. A frontal hypoperfusion syndrome has been identified. There are isolated reports of seizures, encephalopathy, meningitis, encephalitis, and myelitis. The neurological diseases affecting the PNS and muscle in COVID-19 are less frequent and include Guillain-Barré syndrome; Miller Fisher syndrome; polyneuritis cranialis; and rare instances of viral myopathy with rhabdomyolysis. The main conclusion of this review is the pressing need to define the neurology of COVID-19, its frequency, manifestations, neuropathology and pathogenesis. On behalf of the World Federation of Neurology we invite national and regional neurological associations to create local databases to report cases with neurological manifestations observed during the on-going pandemic. International neuroepidemiological collaboration may help define the natural history of this worldwide problem