Descriptions of the paralarvae of two loliginid squids in southern African waters

Morphological differences between paralarvae of two loliginid squid species common in southern African waters (Loligo vulgaris reynaudii and Lolliguncula mercatoris) are described. The differences are: Loligo — "cheek patches" consisting of four dark chromatophores, nine large dark dorsal chromatophores on the mantle, tentacular clubs broad and much wider than tentacle stalks, proximal row of three club suckers with others tetraserial, suckers large enough to appear crowded on the club surface; Lolliguncula — "cheek patches" with three dark chromatophores, two pairs of" large, dark dorsal chromatophores on the mantle, tentacular clubs narrow, proximal club suckers arranged in three pairs, suckers small, not particularly crowded. Relationships with other myopsids are briefly discussed

Energy and economic analysis of a residential Solar Organic Rankine plant

To answer the actual energy, water, economic, social and environmental challenges, renewable, distributed power plants need to be developed. Among renewables, solar tri-generative power plants can be a solution where there is big low temperature heating/cooling demand and small electricity demand, like many residential and industrial utilities. In this case, solar thermal plants can produce thermal energy with low cost and high efficiency. The higher temperature heat not needed by the user can be exploited via Organic Rankine Cycle to produce electrical energy and desalinized water via reverse osmosis. The present paper analyses, via TRNSYS simulation, a system composed of 50 m2 of CPC solar thermal collectors, 3 m3 of thermal storage, a synthetic heat transfer fluid, 3 kWe ORC, 8 kWth absorber, 200 l/h direct reverse osmosis desalination device. The system is able to produce power, heating/cooling and fresh water needs for a residential house. Although system’s components are well known technologies, the integration to a efficient and economic working system is still a challenge. Global energy and economic analyses have been performed. Low temperature heating/cooling terminals allow to increase not only the use of thermal energy but also the ORCand absorber efficiency. ORC-Absorber configuration and relative fluids and temperatures are central. Government support and/or cost reduction of 30% are necessary to have positive NPV and acceptable PBT and IR

Mating Behavior of a Deep-Sea Squid Revealed by in situ Videography and the Study of Archived Specimens

The mating behavior of deep-sea squids is shrouded in mystery. The squids for which mating has been observed use a hectocotylus, a modified arm, for the transfer of sperm packets called spermatophores. However, many deep-sea squid species lack a hectocotylus. We present the first in situ observations of mating behavior in a deep-sea squid that has no hectocotylus but instead uses an elongated terminal organ for the transfer of spermatangia, which are released from the spermatophores and burrow deeply into the female tissue. With remotely operated vehicles (ROVs), we observed two mating pairs of the deep-sea squid Pholidoteuthis adami in the Gulf of Mexico. The male adopted a peculiar position during mating, with its ventral side up and its posterior mantle above the female's head. While the male held the female in what looked like a firm grip, we observed the long terminal organ extending through the funnel of the male, contacting the female dorsal mantle. Examinations of museum specimens show that spermatangia burrow from the outer dorsal mantle into the inner dorsal mantle. This combination of serendipitous in situ observations and archived specimens can be a powerful tool for understanding the behavior of deep-sea animals

Chiral spin currents and spectroscopically accessible single merons in quantum dots

We provide unambiguous theoretical evidence for the formation of correlation-induced isolated merons in rotationally-symmetric quantum dots. Our calculations rely on neither the lowest-Landau-level approximation, nor on the maximum-density-droplet approximation, nor on the existence of a spin-polarized state. For experimentally accessible system parameters, unbound merons condense in the ground state at magnetic fields as low as $B^* = 0.2$ T and for as few as N = 3 confined fermions. The four-fold degenerate ground-state at $B^*$ corresponds to four orthogonal merons $\ket{QC}$ characterized by their topological chirality $C$ and charge $Q$. This degeneracy is lifted by the Rashba and Dresselhaus spin-orbit interaction, which we include perturbatively, yielding spectroscopic accessibility to individual merons. We further derive a closed-form expression for the topological chirality in the form of a chiral spin current and use it to both characterize our states and predict the existence of other topological textures in other regions of phase space, for example, at N=5. Finally, we compare the spin textures of our numerically exact meron states to ansatz wave-functions of merons in quantum Hall droplets and find that the ansatz qualitatively describes the meron states.Comment: 4 pages, 5 figures; minor title change, typos fixe

Biology of the cirrate octopod grimpoteuthis glacialis (cephalopoda; opisthoteuthididae) in the south Shetland Islands, Antarctica

The capture of 52 specimens of the cirrate octopod Grimpoteuthis glacialis (Robson, 1930), of dorsal mantle length 20–165 mm during a 1996 trawling survey near the Antarctic Peninsula allowed the basic biology ofthe species to be examined. Their presence in bottom trawls at depths of 333–879 m, but their absence from benthopelagic and pelagic trawls, is consistent with a primarily benthic habitat. The largest single sample, 40animals, came from a soft mud bottom and highlights the patchy nature of the distribution. Males tended to be bigger in total length and mass than females of similar mantle length. The males, however, were mature ata smaller size. Mature males have tiny sperm packets, rather than typical cephalopod spermatophores, in their distal reproductive tract. Mature females have large, smooth eggs in the proximal oviduct, in the huge oviducal gland and in the distal oviduct. Eggs in the distal oviduct have a thick, sticky coating that hardens in seawater into a secondary egg case. Ovarian eggs vary greatly in size, possibly indicating protracted egg laying.Observations on live animals indicate that the species swims primarily by fin action, rather than by jetting or medusoid pulses with the arm/web complex. It may be capable of limited changes in colour pattern,especially on the oral surface of the web. Three pairs of surface structures that appear superficially to be white spots anterior to the eyes and near the bases of the fins are actually transparent patches in the skin. Whenconsidered in association with the transparent subdermal layer and the anatomy of the eyes, optic nerves and optic lobes, these clear patches seem to function in detecting unfocused light on the horizontal plane of the benthic animal

The evolution of coleoid cephalopods and their present biodiversity and ecology

The present status of phylogeny and classification in coleoid cephalopods and the effect of evolution on the present ecology and biodiversity in the group are examined. The basis of knowledge of cephalopod phylogenywas formulated by Naef in the early 1920s, and his ideas and the progress made in the intervening 75 years are investigated. In the process, the roles that transitions between pelagic and benthic habitats played in the evolution of cephalopods are noted, and the possibility is advanced that the most recent “oceanic anoxic event” may have established a time marker for the divergence of some oegopsid families. The major advances since Naef’s work are: 1. The unusual nature of Vampyroteuthis has been recognized; 2. The sister-group relationship between the Neocoleoidea and the Belemnoidea has been established, but requires further confirmation;3. Monophyly has been confirmed for the Decapodiformes (new name), Octopodiformes and Octopoda by molecular and morphological methodologies; 4. The dates of origin of the Belemnoidea, Neocoleoidea, Sepioidea and fossil teuthoids have been extended to considerably earlier times. The major unsolved phylogenetic problems in need of immediate attention are the position of the Myopsida, relationships within the Sepioidea, the identification of the basal nodes within the Oegopsida, and the relationships of most “fossil teuthoids.

Quantum phase slips in superconducting Nb nanowire networks deposited on self-assembled Si templates

Robust porous silicon substrates were employed for generating interconnected networks of superconducting ultrathin Nb nanowires. Scanning electron microscopy analysis was performed to investigate the morphology of the samples, which constitute of polycrystalline single wires with grain size of about 10 nm. The samples exhibit nonzero resistance over a broad temperature range below the critical temperature, fingerprint of phase slippage processes. The transport data are satisfactory reproduced by models describing both thermal and quantum fluctuations of the superconducting order parameter in thin homogeneous superconducting wires.Comment: accepted for publication on Applied Physics Letter

Fez1/Lzts1 a new mitotic regulator implicated in cancer development

Considerable evidence has accumulated suggesting that cancer has genetic origin, based on the development of genomic alterations, such as deletions, mutations, and/or methylations in critical genes for homeostasis of cellular functions, including cell survival, DNA replication and cell cycle control. Mechanism controlling the precise timing and sequence of cell cycle events as well as checkpoints insuring fidelity of those events are key targets that when disrupted could result in tumorigenesis. Mitosis is the process by which a cell duplicates its genetic information (DNA), in order to generate two, identical, daughter cells. In addition each daughter cell must receive one centrosome and the appropriate complements of cytoplasm and organelles. This process is conventionally divided in to five distinct stages: prophase, prometaphase, metaphase, anaphase and telophase that correspond to a different morphology of the cell. The entry into mitosis (M) is under the control of the cyclin dependent kinase Cdk1. During G2, the kinases Wee1 and Myt1 phosphorylate Cdk1 at T14/Y15 residues, rendering it inactive. The transition from G2 to M is promoted by the activation of Cdk1 via dephosphorylation by the Cdk1 phosphatase Cdc25C. Activated Cdk1 complexes translocate into the nucleus during prophase where phosphorylate numerous substrates in order to enhance their activation as the cells progresses trough prophase, prometaphase, and metaphase