Vasopora ceramica n. gen., n. sp.—a new abyssal cyclostome bryozoan from polymetallic nodules in the Russian exploration area, Clarion–Clipperton Fracture Zone, eastern Pacific Ocean

A new abyssal cyclostome bryozoan genus and species, Vasopora ceramica n. gen., n. sp., is described from the eastern Russian exploration area of the Clarion–Clipperton Fracture Zone based on newly collected material from Yuzhmorgeologiya GLD4–19 station 421 (13.23408° N, 134.22180° W, 4809 m depth). Generic characters include an erect pedunculate colony with a distinct boundary between column and flared capitulum, short autozooidal peristomes in a single whorl, numerous alveoli, a central unidirectional sac-like gonozooid covered by a surficial network of crossed ridges continuous with adjacent rims of alveoli, a laterally opening ooeciopore, and the entire capitulum surface being minutely densely granular to subspinulate. Whereas the skeletal microstructure of the capitulum surface comprises irregular imbricated crystallites, the column has a planar-spherulitic fabric of acicular crystallites in fan-like arrays, and there are no pseudopores. The sharp boundary between capitulum and column, with their different microstructure separates Vasopora n. gen. from the two existing genera of Alyonushkidae that are found in the same environment. Vasopora n. gen. has a stalk formed of calcified exterior wall, whereas it is interior-walled in Alyonushka and Calyssopora.

Hairier than Putnam Thought

This chapter is a short note, co-written with Stephen Read, reacting to Hilary Putnam’s observation in his ‘Vagueness and Alternative Logic’ that intuitionistic logic would block the transition from the negation of the usual universally quantified conditional form of major premise for a Sorites to the assertion of a sharp boundary to the target predicate in the series concerned, and would thus allow the paradox to be reconceived as a straightforward reductio of its major premise. It is pointed out that a Sorites need not employ that form of major premise but can instead proceed, in intuitionistic logic, from the negation of the existential claim that the series in question contains a sharp boundary and that, while an intuitionistically suspect double negation elimination step would still be needed to enforce the unpalatable conclusion that the predicate in question indeed has a sharp boundary, nothing like the semantic motivation that the Intuitionists have favoured in mathematics for a restriction on double negation elimination can be operative in this context.

THE INTERACTION OF A SUPERSONIC PLASMA JET CONTAINING NANOPARTICLES WITH A SUBSTRATE

In the framework of a multi-fluid axisymmetric hydrodynamic model, the interaction of a supersonic plasma jet containing nanoparticles with a flat substrate is investigated using computer simulation. In particular, the fluxes of nanoparticles on the substrate are studied at plasma inlet pressure P0=1...100 Torr. The results show that a shock wave is formed near the substrate, which affects the energy of nanoparticles and their fluxes on the substrate. The width of the region along the radius, where the flow of nanoparticles onto the substrate is essential, depends on the plasma pressure in the jet. At large values of plasma pressure (P0≥75 Torr) a cloud of nanoparticles with a sharp boundary is formedon the axis of the plasma jet near the substrate. Interacting with this cloud, nanoparticles moving in the plasma jet, lose directed energy and their flow on the substrate near the axis of the jet is zero.

Wildfire Events at the Triassic-Jurassic Boundary of the Tabas Basin, Central Iran

This paper presents organic geochemical evidence pointing to the occurrence of wildfire events at the Triassic-Jurassic boundary in Central Iran. The studied outcrop section (the Kamarmacheh Kuh section) is comprised of the Upper Triassic Nayband Formation which passes conformably into the Lower Jurassic Ab-e-Haji Formation with no sharp boundary. Organic petrographical studies reveal a higher concentration of semi-fusinite macerals and microscopic charcoal at the boundary between studied formations. This observation can be an evidence for widespread wildfire events at the Triassic-Jurassic boundary of the studied area. Following these fires, vast areas of land were exposed for erosion and large volumes of clastic sediments were provided due to increased run-off. This agrees well with previous sedimentological and stratigraphical studies suggesting a major change in the depositional conditions from marine to non-marine at the Triassic-Jurassic boundary of the Tabas Basin. These findings can have important implications about paleo-depositional settings of the studied formations and the nature of the associated organic matter.

A new model to explain energetic electrons behind dipolarization front

<p>Dipolarization front—a sharp boundary leading reconnection jets and producing colorful auroras—plays a crucial role in the magnetotail energy conversion. Behind this front, sometimes energetic electrons appear, whereas sometimes they vanish. The reason causing such uncertainty is still a mystery, owing to the lack of high-resolution measurements. Here we propose a novel model to uncover this mystery: we find that behind the front there exists a magnetic bottle with time-varying belly but steady neck. When the belly is expanding—like a man getting fat—the magnetic bottle is formed and energetic electrons are trapped; when the belly is contracting—like a man getting slim—the magnetic bottle disappears and energetic electrons are expelled. This model clearly explains how energetic electrons are trapped in the Earth’s magnetotail and in principle it can be applied to other planetary magnetotails. </p>