New data on sponges from Svalbard Archipelago with a description of a new species of Halicnemia

Sponge fauna from the west and south of Svalbard archipelago was studied. A total of 28 species of sponges were identified. Five of them are new records to the study area and one is new to science. New records for Spitsbergen are: Axinella hispida (Koltun 1959), Haliclona rossica (Hentschel 1929), Myxilla (Myxilla) perspinosa (Lundbeck 1905), Sphaerotylus borealis (Swartschewsky 1906) and Suberites carnosus (Johnston 1842). A new species of sponge, Halicnemia wagini sp. nov., collected south-west of Spitsbergen on the continental slope at a depth of 423–425 m, is described. It is similar to Halicnemia patera (Bowerbank 1864) and H. verticillata (Bowerbank 1866) in skeleton architecture, but significantly differs in its spicule complement and external appearance. Primarily, distinct differences concern the morphology of microscleres. In comparison with Halicnemia patera, the new species has an additional category of acanthose microscleres presented by microstrongyles, while microscleres of H. verticillata are only slightly curved and also verticillately spined. The study area, west of Spitsbergen, establishes close relationships with North Atlantic due to warm Atlantic waters of the West Spitsbergen Current. Proximity of the new species to the North Atlantic representatives of Halicnemia genus allowed us to suggest that H. wagini sp. nov., both ecologically and morphologically, has stood apart as a distinct biological species in the conditions of the Arctic.

http://www.zoobank.org/lsid:zoobank.org:pub:2A09537B-63D7-4F07-A2AB-9C707A686333     

Two-dimensional gas of massless Dirac fermions in graphene

Quantum electrodynamics (resulting from the merger of quantum mechanics and relativity theory) has provided a clear understanding of phenomena ranging from particle physics to cosmology and from astrophysics to quantum chemistry. The ideas underlying quantum electrodynamics also influence the theory of condensed matter, but quantum relativistic effects are usually minute in the known experimental systems that can be described accurately by the non-relativistic Schr?dinger equation. Here we report an experimental study of a condensed-matter system (graphene, a single atomic layer of carbon) in which electron transport is essentially governed by Dirac's (relativistic) equation. The charge carriers in graphene mimic relativistic particles with zero rest mass and have an effective 'speed of light' c* approximately 10(6) m s(-1). Our study reveals a variety of unusual phenomena that are characteristic of two-dimensional Dirac fermions. In particular we have observed the following: first, graphene's conductivity never falls below a minimum value corresponding to the quantum unit of conductance, even when concentrations of charge carriers tend to zero; second, the integer quantum Hall effect in graphene is anomalous in that it occurs at half-integer filling factors; and third, the cyclotron mass m(c) of massless carriers in graphene is described by E = m(c)c*2. This two-dimensional system is not only interesting in itself but also allows access to the subtle and rich physics of quantum electrodynamics in a bench-top experiment.     

Mutations in LGI1 cause autosomal-dominant partial epilepsy with auditory features.

The epilepsies are a common, clinically heterogeneous group of disorders defined by recurrent unprovoked seizures. Here we describe identification of the causative gene in autosomal-dominant partial epilepsy with auditory features (ADPEAF, MIM 600512), a rare form of idiopathic lateral temporal lobe epilepsy characterized by partial seizures with auditory disturbances. We constructed a complete, 4.2-Mb physical map across the genetically implicated disease-gene region, identified 28 putative genes (Fig. 1) and resequenced all or part of 21 genes before identifying presumptive mutations in one copy of the leucine-rich, glioma-inactivated 1 gene (LGI1) in each of five families with ADPEAF. Previous studies have indicated that loss of both copies of LGI1 promotes glial tumor progression. We show that the expression pattern of mouse Lgi1 is predominantly neuronal and is consistent with the anatomic regions involved in temporal lobe epilepsy. Discovery of LGI1 as a cause of ADPEAF suggests new avenues for research on pathogenic mechanisms of idiopathic epilepsies.