Ruth Turner's studies of xylophagaids, wood-boring bivalves, documented the very existence of wood-borers in the deep sea and made the northwestern Atlantic fauna among the best known. However, her work focused on specimens from less than 2000 m depth. Here study of specimens from depths over 2000 m deposited in the Smithsonian collections extends our knowledge of this fauna.
View Article and Find Full Text PDFDoes warmth from hydrothermal springs play a vital role in the biology and ecology of abyssal animals? Deep off central California, thousands of octopus () migrate through cold dark waters to hydrothermal springs near an extinct volcano to mate, nest, and die, forming the largest known aggregation of octopus on Earth. Warmth from the springs plays a key role by raising metabolic rates, speeding embryonic development, and presumably increasing reproductive success; we show that brood times for females are ~1.8 years, far faster than expected for abyssal octopods.
View Article and Find Full Text PDFPhylogenies for Octopoda have, until now, been based on morphological characters or a few genes. Here we provide the complete mitogenomes and the nuclear 18S and 28S ribosomal genes of twenty Octopoda specimens, comprising 18 species of Cirrata and Incirrata, representing 13 genera and all five putative families of Cirrata (Cirroctopodidae, Cirroteuthidae, Grimpoteuthidae, Opisthoteuthidae and Stauroteuthidae) and six families of Incirrata (Amphitretidae, Argonautidae, Bathypolypodidae, Eledonidae, Enteroctopodidae, and Megaleledonidae) which were assembled using genome skimming. Phylogenetic trees were built using Maximum Likelihood and Bayesian Inference with several alignment matrices.
View Article and Find Full Text PDFRes Number Theory
September 2022
We consider spaces of modular forms attached to definite orthogonal groups of low even rank and nontrivial level, equipped with Hecke operators defined by Kneser neighbours. After reviewing algorithms to compute with these spaces, we investigate endoscopy using theta series and a theorem of Rallis. Along the way, we exhibit many examples and pose several conjectures.
View Article and Find Full Text PDFWe study the hypergeometric functions associated to five one-parameter deformations of Delsarte K3 quartic hypersurfaces in projective space. We compute all of their Picard-Fuchs differential equations; we count points using Gauss sums and rewrite this in terms of finite-field hypergeometric sums; then we match up each differential equation to a factor of the zeta function, and we write this in terms of global -functions. This computation gives a complete, explicit description of the motives for these pencils in terms of hypergeometric motives.
View Article and Find Full Text PDFBlocking interactions between PD-1 and PD-L1 opens a new era of cancer treatment involving immunity modulation. Although most immunotherapies use monoclonal antibodies, small-molecule inhibitors offer advantages. To facilitate development of small-molecule therapeutics, we implemented a rapid approach to characterize the binding interfaces of small-molecule inhibitors with PD-L1.
View Article and Find Full Text PDFBackground: There is growing interest in mining polymetallic nodules from the abyssal Clarion-Clipperton Zone (CCZ) in the tropical Pacific Ocean. Despite having been the focus of environmental studies for decades, the benthic megafauna of the CCZ remain poorly known. To predict and manage the environmental impacts of mining in the CCZ, baseline knowledge of the megafauna is essential.
View Article and Find Full Text PDFDeep-sea bivalves of the Xylophagaidae, a poorly known group, are obligate wood-borers. Deployment of wood in three submarine canyons off the Iberian coast, the Blanes and La Fonera Canyons (Mediterranean Sea) and the Avilés Canyon (Cantabric Sea, Bay of Biscay), lead to the discovery of four xylophagaid species in our samples. Xylophaga dorsalis (the dominant species), X.
View Article and Find Full Text PDFBackground: Radiofrequency ablation (RFA) is considered a curative procedure for typical atrial flutter (AFL); however, patients remain at risk for developing new atrial fibrillation (AF).
Objective: The purpose of this study was to determine the incidence and predictors of new-onset AF and stroke after RFA of isolated AFL in a multicenter cohort.
Methods: The study included 315 consecutive patients who underwent successful RFA of isolated, typical AFL from 2006 to 2013 at 4 community and teaching hospitals.
The fauna of deep-sea hydrothermal vents are among the most isolated and inaccessible biological communities on Earth. Most vent sites can only be visited by subsea vehicles, which can and do move freely among these communities. Researchers assume individuals of the regionally homogeneous vent fauna are killed by the change in hydrostatic pressure the animals experience when the subsea vehicles, which collected them, rise to the surface.
View Article and Find Full Text PDFReconstruction of the phylogeny of the five extant classes of the phylum Echinodermata has proven difficult. Results concerning higher-level taxonomic relationships among echinoderms are sensitive to the choice of analytical parameters and methods. Moreover, the proposal of a putative sixth class based on a small enigmatic disc-shaped echinoderm, Xyloplax, from the deep seas of the Bahamas and New Zealand in the 1980s further complicated the problem.
View Article and Find Full Text PDFTaxonomic accounts of octopodids frequently describe the spermatophore, the penis that releases the spermatophore from the internal organs, and the ligula and calamus that transfer it to a female. To explore relationships among these male features and body size, this study applies principal components analysis to data from 43 species of the family Octopodidae, or benthic octopuses. Covariation in penis and mantle length opposed by covariation in ligula and calamus lengths forms primary shape variation.
View Article and Find Full Text PDFThe use of color-coded tissue Doppler echocardiography has resulted in rapid technological advances in the evaluation of cardiac function. This article describes some of these exciting new advances, including curved M-mode analysis and strain rate imaging. Data from studies in animals and humans are presented to demonstrate the potential clinical use of this new echocardiographic diagnostic tool.
View Article and Find Full Text PDFVideotapes made from the submersible Alvin on Baby Bare, a 2600-m-deep North Pacific basalt outcrop, and at two other deep-sea localities document that octopuses of the genera Graneledone and Benthoctopus attach their eggs to hard substrate and apparently brood them through development. The behavior of brooding females was generally similar to that of shallow-water octopuses, but the genera showed apparent differences. In addition to the high density of brooding females observed at Baby Bare, which may relate to the increased availability of exposed hard substrates for egg attachment and of prey, females are suggested to increasingly associate with hard substrates as they mature.
View Article and Find Full Text PDFHuman pancreatic adenocarcinomas lose the ability to express sst2, the somatostatin receptor, which mediates the antiproliferative effect of somatostatin. Reintroducing sst2 into human pancreatic cancer cells by stable expression evokes an autocrine negative feedback loop leading to a constitutive activation of the sst2 gene and an inhibition of cell proliferation and tumorigenicity. In vivo studies have been conducted in athymic mice to investigate the antitumor bystander effects resulting from the transfer of the sst2 gene into human pancreatic cancer cell line BxPC-3.
View Article and Find Full Text PDFIn the translucent mid-water octopod Eledonella pygmaea, the posterior salivary glands that release proteolytic enzymes into the esophageal crop grow five times faster in males than in females. I suggest that the sexes vertically partition the water column and that large glands have evolved in males as a result of their deepwater habitat. Members of the species undergo ontogenetic vertical descent and are suggested to mate at the lower end of the adult depth range where receptive females signal males with light organs.
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