Substitution-based structures with absolutely continuous spectrum

By generalising Rudin’s construction of an aperiodic sequence, we derive new substitution-based structures which have a purely absolutely continuous diffraction measure and a mixed dynamical spectrum, with absolutely continuous and pure point parts. We discuss several examples, including a construction based on Fourier matrices which yields constant-length substitutions for any length

Relief of dysphagia due to advanced achalasia by endoscopic creation of an esophagogastric bypass anastomosis through an epiphrenic diverticulum

An 85-year-old man with long-standing dysphagia and multiple admissions for aspiration pneumonia was referred for evaluation

Ultracold collisions in tight harmonic traps: Quantum defect model and application to metastable helium atoms

We analyze a system of two colliding ultracold atoms under strong harmonic confinement from the viewpoint of quantum defect theory and formulate a generalized self-consistent method for determining the allowed energies. We also present two highly efficient computational methods for determining the bound state energies and eigenfunctions of such systems. The perturbed harmonic oscillator problem is characterized by a long asymptotic region beyond the effective range of the interatomic potential. The first method, which is based on quantum defect theory and is an adaptation of a technique developed by one of the authors (GP) for highly excited states in a modified Coulomb potential, is very efficient for integrating through this outer region. The second method is a direct numerical solution of the radial Schr\"{o}dinger equation using a discrete variable representation of the kinetic energy operator and a scaled radial coordinate grid. The methods are applied to the case of trapped spin-polarized metastable helium atoms. The calculated eigenvalues agree very closely for the two methods, and with those computed self-consistently using the generalized self-consistent method.Comment: 11 pages,REVTEX, text substantially revised, title modifie

Confirmed feasibility of a satellite tracker attachment method on small juvenile hawksbill turtles Eretmochelys imbricata

Satellite trackers can be used for studying sea turtle movement, illuminating their migrations and behaviours. However, many studies have focused on adult turtles, with uneven species representation, despite the importance of understanding movement and habitat use of turtles at all life-stages. Furthermore, few publications detail successful satellite tracker attachment methods, particularly for juveniles. Smaller-sized juvenile sea turtles often have an irregularly shaped carapace and are fast growing, rendering the attachment of rigid trackers in a safe and durable manner challenging. Juvenile hawksbill turtles’ specific carapace shape and imbricated scute arrangement further complicate satellite tracker attachment compared to juveniles of other turtle species. This study’s objective was to confirm the feasibility of an attachment method that would allow small-sized juvenile hawksbill turtles (~267-345 mm curved carapace length) to continue growing, without tracker loss or damage to underlying scutes. Replica trackers were made of resin (simulating Wildlife Computer Spot-387 trackers), and attached with epoxy, silicone and neoprene, using a technique modified from those used on neonate loggerheads and Kemp’s ridleys. Throughout the study (3.5 mo), replica trackers remained attached, the turtles grew up to 114% heavier and 25% longer, and all turtles appeared clinically healthy and active. Furthermore, all scutes were undamaged after tracker removal. As a critically endangered species, the paucity of data on hawksbill turtles, and specifically juveniles, can hinder evidence-based management decision-making. The improved ability to satellite track juvenile hawksbills can, therefore, help better our understanding of their ecology and inform management and conservation practices for this species

Towards the identification of the soil microbiome community associated with Longleaf Pine

This project is part of a larger study looking at the restoration of the Long-leaf Pine ecosystem in certain Wildlife Management Areas (WMA) in Northwest Georgia. As part of this larger study another group of researchers has been looking at changes in the plant community in the same plots used for this soil microbiome research. Our long-term aim is to look for potential associations between the above and below-ground community structures. Although research has shown that the health and composition of the microbiome surrounding the roots of plants has a significant impact on the ability of plants to fight and survive various stressors (Wei et al. 2019), the full extent of the complex system of feedback mechanisms between the rhizosphere and soil microbiome, and the above ground plant communities is not yet understood. We collected soil samples from six plots located in the Sheffield WMA located in Paulding County, GA. Except for two plots at the savanna site, with slopes south or west facing; soil samples were collected from either north or south facing hillsides. Within each plot, samples were collected in sterile plastic tubes at the center of the plot and 10 m above and below from the center. Five random sub samples were taken from each tube for DNA extraction using a commercially available kit. Given that plant communities appear to differ between north and south facing slopes, we hypothesize that the soil microbiome will also differ significantly in north versus south facing areas. We also hypothesize that the microbiome in the savanna plots, which are actively being restored for Longleaf pine, will be distinct from all others

Radiocarbon chronology and environmental context of Last Glacial Maximum human occupation in Switzerland

Central Europe during the Last Glacial Maximum (LGM) was dominated by polar desert and steppe-tundra biomes. Despite this, a human presence during this time period is evident at several locations across the region, including in Switzerland, less than 50 km from the Alpine ice sheet margin. It has been hypothesised that such human activity may have been restricted to brief periods of climatic warming within the LGM, but chronological information from many of these sites are currently too poorly resolved to corroborate this. Here we present a revised chronology of LGM human occupation in Switzerland. AMS radiocarbon dating of cut-marked reindeer (Rangifer tarandus) bones from the sites of Kastelhöhle-Nord and Y-Höhle indicates human occupation of Switzerland was most likely restricted to between 23,400 and 22,800 cal. BP. This timeframe corresponds to Greenland Interstadial 2, a brief warming phase, supporting the hypothesis that human presence was facilitated by favourable climatic episodes. Carbon, nitrogen and sulphur stable isotope analysis of the fauna provides palaeoenvironmental information for this time period. These findings contribute to our understanding of human activity in ice-marginal environments and have implications for understanding cultural connections across central Europe during the LGM

Single Balloon Enteroscopy-Assisted ERCP for Treatment of Cholangitis in a Patient with a Kasai Portoenterostomy

Primary therapy for biliary atresia is a surgical hepatoportoenterostomy (Kasai procedure), which has been shown to reduce mortality, but is frequently complicated by ascending cholangitis and the development of biliary cirrhosis. Previously reported therapy for recurrent cholangitis caused by biliary obstruction has included surgical revision and percutaneous biliary drainage, but ERCP has not been previously described. Here we report a patient with recurrent cholangitis following a Kasai procedure and an anastomotic stricture successfully treated with single balloon enteroscopy-assisted ERCP. This novel technique could be considered in patients with this common complication of the Kasai procedure, and may impact long-term outcomes in this patient population

Single-balloon enteroscopy: results from an initial experience at a U.S. tertiary-care center

Single Balloon Enteroscopy (SBE) is a novel deep enteroscopy modality for diagnosis and treatment of disorders of the small bowel