Variations in the Reproductive Activities of Arctic Terns at Churchill, Manitoba

Nest locations and contents were observed in 16 colonies over a 3-year period. Laying times correlated with spring temperatures, but not with colony size. Clutch size increased with time between ice breakup and laying onset. Egg losses were insufficient to account for differences in clutch size. The results are taken to indicate that under arctic conditions, variations in clutch size, timing of the nesting cycle, and associated events in the Arctic Tern are closely related to variations in the physical environment

An aggregation of juvenile Youngina from the Beaufort Group, Karoo Basin, South Africa

Main articleAn assemblage of five fully-articulated juvenile skeletons of Youngina has been recovered from the Late Permian strata of the south-western Karoo Basin. These 12-cm-long skeletons are not only the first articulated juveniles of this taxon, but also the oldest yet found in the Karoo Basin. They are preserved in overbank mudrocks of the Hoedemaker Member (Beaufort Group, Adelaide Subgroup) on the farm Leeukloof 43 in the Beaufort West district. Although they are estimated to be some three million years older than previously described Youngina, these specimens show no significant skeletal differences. The high degree of articulation and the spatial arrangement of these skeletons in a dish-shaped hollow is compelling evidence for them having huddled together within an underground burrow. Taphonomic analysis of associated fossils indicates that this was probably a mechanism to reduce water loss during drought on the ancient Karoo floodplains .Non

Principles and Clinical Applications of Magnetic Resonance

A review is presented which covers the basic theory of nuclear magnetic resonance (NMR) with regard to angular momentum, magnetic moments, and the classical mechanical description of the NMR experiment. Longitudinal (T,) and Transverse (T2) relaxation times are defined as well as the basic pulse sequences used for their measurement. In particular, the 180°-t-90° and the Hahn Spin Echo pulse sequences are described in detail. Basic Magnetic Resonance Imaging (MRI) theory is discussed with regard to slice selection, frequency encoding, and phase encoding to define the imaged volume element. The equations defining the amount of Tt , T2 , and proton density which contribute to the images are discussed. Common MRI pulsing sequences are described in detail as well as the imaging time equation. Recent in-vivo magnetic resonance studies involving the use of contrast agents, and the use of localized spectroscopy, specifically 13C, 19F, MNa and 39K, are discussed

Using machine learning for automatic identification of evidence-based health information on the web

Automatic assessment of the quality of online health information is a need especially with the massive growth of online content. In this paper, we present an approach to assessing the quality of health webpages based on their content rather than on purely technical features, by applying machine learning techniques to the automatic identification of evidence-based health information. Several machine learning approaches were applied to learn classifiers using different combinations of features. Three datasets were used in this study for three different diseases, namely shingles, flu and migraine. The results obtained using the classifiers were promising in terms of precision and recall especially with diseases with few different pathogenic mechanisms

Self Diagnostic Accelerometer for Mission Critical Health Monitoring of Aircraft and Spacecraft Engines

A self diagnostic accelerometer system has been shown to be sensitive to multiple failure modes of charge mode accelerometers. These failures include sensor structural damage, an electrical open circuit and most importantly sensor detachment. In this paper, experimental work that was performed to determine the capabilities of a self diagnostic accelerometer system while operating in the presence of various levels of mechanical noise, emulating real world conditions, is presented. The results show that the system can successfully conduct a self diagnostic routine under these conditions

Geochemical and microstructural characterisation of two species of cool-water bivalves (Fulvia tenuicostata and Soletellina biradiata) from Western Australia

The shells of two marine bivalve species (Fulvia tenuicostata and Soletellina biradiata) endemic to south Western Australia have been characterised using a combined crystallographic, spectroscopic and geochemical approach. Both species have been described previously as purely aragonitic; however, this study identified the presence of three phases, namely aragonite, calcite and Mg-calcite, using XRD analysis. Data obtained via confocal Raman spectroscopy, electron probe microanalysis and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) show correlations between Mg • S and Mg • P in F. tenuicostata and between Sr • S and S • Ba in S. biradiata. The composition of the organic macromolecules that constitute the shell organic matrix (i.e. the soluble phosphorus-dominated and/or insoluble sulfur-dominated fraction) influences the incorporation of Mg, Sr and Ba into the crystal lattice. Ionic substitution, particularly Ca2+ by Mg2+ in calcite in F. tenuicostata, appears to have been promoted by the combination of both S- and P-dominated organic macromolecules. The elemental composition of these two marine bivalve shells is species specific and influenced by many factors, such as crystallographic structure, organic macromolecule composition and environmental setting. In order to reliably use bivalve shells as proxies for paleoenvironmental reconstructions, both the organic and inorganic crystalline material need to be characterised to account for all influencing factors and accurately describe the "vital effect"

Ectopic expression of Thy-1 in the kidneys of transgenic mice induces functional and proliferative abnormalities.

Hybrid human--mouse Thy-1.1 genes were injected into pronuclei of Thy-1.2 mice to produce transgenic animals. A hybrid gene composed of the 5' part of the mouse Thy-1.1 gene combined with the 3' human untranslated regions was expressed abnormally in the kidney podocytes, which resulted in severe protein-uria and subsequent death in several founder mice. A hybrid Thy-1 gene composed of the human coding region with the 5' and 3' flanking regions of the mouse gene was expressed abnormally in a different part of the kidney (the tubular epithelia), which resulted in a proliferative kidney disorder. In addition, a neoplasm was found in the brain of one of these mice. These results show that the Thy-1 protein can play an important role in the activation, proliferation, and differentiation of many different cell types

Investigating the medium range order in amorphous Ta₂O₅ coatings

Ion-beam sputtered amorphous heavy metal oxides, such as Ta2O5, are widely used as the high refractive index layer of highly reflective dielectric coatings. Such coatings are used in the ground based Laser Interferometer Gravitational-wave Observatory (LIGO), in which mechanical loss, directly related to Brownian thermal noise, from the coatings forms an important limit to the sensitivity of the LIGO detector. It has previously been shown that heat-treatment and TiO2 doping of amorphous Ta2O5 coatings causes significant changes to the levels of mechanical loss measured and is thought to result from changes in the atomic structure. This work aims to find ways to reduce the levels of mechanical loss in the coatings by understanding the atomic structure properties that are responsible for it, and thus helping to increase the LIGO detector sensitivity. Using a combination of Reduced Density Functions (RDFs) from electron diffraction and Fluctuation Electron Microscopy (FEM), we probe the medium range order (in the 2-3 nm range) of these amorphous coatings

The hepatic response following infection with Listeria monocytogenes

In the present study, we investigated the liver specific response upon infection with L. monocytogenes, a model pathogen for Gram-positive infections over a period of 5days. We used whole genome microarray chips to determine the temporal transcriptome at five observation points. Relative mRNA levels were validated for a representative subset of genes by quantitative Real-Time PCR. In the analysis of these data we followed a strict methodology. The quality of microarray data was ensured by several measures, including quality control tools developed and optimized at our institution. The biological effects of differentially expressed genes were investigated and interpretation of these results was followed by confirmatory experiments. In conclusion, this work allows a unique insight into regulatory networks of several biological processes and interconnections following an infection with L. monocytogenes. Based on our results and by integration of known literature, LXR-α and related transcription factors are proposed to be fundamental for the regulation of hepatic and subsequently systemic response to pathogens.In der vorliegenden Studie untersuchten wir die Leber-spezifische Antwort nach Infektion mit L. monocytogenes, ein Gram-positives Modell-Bakterium über einen Zeitraum von 5 Tagen hinweg. Dabei machten wir Gebrauch von whole genome microarrays, mit dessen Hilfe das transiente Transkriptom zu fünf verschiedenen Zeitpunkten bestimmt wurde. Relative mRNA-Veränderungen wurden anhand einer repräsentativen Auswahl von Genen mittels quantitativer Echtzeit-PCR validiert. Die Analyse gewonnener Daten folgte einer strikten Methodologie. Die Qualität der microarray Daten wurde durch bioinformatische Programme, die an unserem Institut enwickelt und optimiert wurden, gesichert. Basierend auf dem Expressionsmuster differenziell regulierter Gene wurden biologische Rückschlüsse gezogen, die in subsequenten Experimenten untersucht und validiert wurden. Zusammenfassend bietet diese Arbeit einen einzigartigen Einblick in regulatorische Netzwerke verschiedenster biologischer Funktionen und Interaktionen nach Infektion mit L. monocytogenes. Basierend auf diesen Resultaten und eingebettet in bekannte Literatur, stellt sich eine herausragende Rolle für LXR und verwandte Transkriptionsfaktoren bei der hepatischen und subsequent auch systemischen Immunantwort dar