Memorial University of Newfoundland

About: Memorial University of Newfoundland is a education organization based out in St. John's, Newfoundland and Labrador, Canada. It is known for research contribution in the topics: Population & Context (language use). The organization has 13818 authors who have published 27785 publications receiving 743594 citations. The organization is also known as: Memorial University & Memorial University of Newfoundland and Labrador.

Calcitonin plays a critical role in regulating skeletal mineral metabolism during lactation.

Abstract: The maternal skeleton rapidly demineralizes during lactation to provide calcium to milk, responding to the stimuli of estrogen deficiency and mammary-secreted PTH-related protein. We used calcitonin/calcitonin gene-related peptide-α (Ctcgrp) null mice to determine whether calcitonin also modulates lactational mineral metabolism. During 21 d of lactation, spine bone mineral content dropped 53.6% in Ctcgrp nulls vs. 23.6% in wild-type (WT) siblings (P < 0.0002). After weaning, bone mineral content returned fully to baseline in 18.1 d in Ctcgrp null vs. 13.1 d in WT (P < 0.01) mice. Daily treatment with salmon calcitonin from the onset of lactation normalized the losses in Ctcgrp null mice, whereas calcitonin gene-related peptide-α or vehicle was without effect. Compared with WT, Ctcgrp null mice had increased circulating levels of PTH and up-regulation of mammary gland PTH-related protein mRNA. In addition, lactation caused the Ctcgrp null skeleton to undergo more trabecular thinning and increased trabecula...

Volatile control of contrasting trace element distributions in peralkaline granitic and volcanic rocks

Abstract: Anomalous enrichments of Zr (>500 ppm), Zn (> 100 ppm), Nb (>25 ppm), Y (>60 ppm), Th (>20 pm), U (> 5 ppm), LREE (>230 ppm) and HREE (>35ppm), and high Rb/Sr (>5) characterize peralkaline granites, in contrast to their peraluminous and calc-alkaline equivalents. Within the peralkaline suite, comenditic and pantelleritic volcanics exhibit two- to five-fold increases in the concentrations of these trace elements over comagmatic granites. These cannot be explained by crystal- liquid fractionation processes, and require the evolution of a sodium-enriched fluid. Corresponding trace element increases in the granites in areas of alkali metasomatism support this argument, and reflect the partial confinement of this volatile phase within the high-level magma chambers. REE studies in particular might eventually allow an evaluation of the role of Cl− versus F− and CO3-complexing in the evolution of the volatile fluid.

A new fully convolutional neural network for semantic segmentation of polarimetric SAR imagery in complex land cover ecosystem

Abstract: Despite the application of state-of-the-art fully Convolutional Neural Networks (CNNs) for semantic segmentation of very high-resolution optical imagery, their capacity has not yet been thoroughly examined for the classification of Synthetic Aperture Radar (SAR) images. The presence of speckle noise, the absence of efficient feature expression, and the limited availability of labelled SAR samples have hindered the application of the state-of-the-art CNNs for the classification of SAR imagery. This is of great concern for mapping complex land cover ecosystems, such as wetlands, where backscattering/spectrally similar signatures of land cover units further complicate the matter. Accordingly, we propose a new Fully Convolutional Network (FCN) architecture that can be trained in an end-to-end scheme and is specifically designed for the classification of wetland complexes using polarimetric SAR (PolSAR) imagery. The proposed architecture follows an encoder-decoder paradigm, wherein the input data are fed into a stack of convolutional filters (encoder) to extract high-level abstract features and a stack of transposed convolutional filters (decoder) to gradually up-sample the low resolution output to the spatial resolution of the original input image. The proposed network also benefits from recent advances in CNN designs, namely the addition of inception modules and skip connections with residual units. The former component improves multi-scale inference and enriches contextual information, while the latter contributes to the recovery of more detailed information and simplifies optimization. Moreover, an in-depth investigation of the learned features via opening the black box demonstrates that convolutional filters extract discriminative polarimetric features, thus mitigating the limitation of the feature engineering design in PolSAR image processing. Experimental results from full polarimetric RADARSAT-2 imagery illustrate that the proposed network outperforms the conventional random forest classifier and the state-of-the-art FCNs, such as FCN-32s, FCN-16s, FCN-8s, and SegNet, both visually and numerically for wetland mapping.

Glucocorticoid-dependent oncogenic transformation by type 16 but not type 11 human papilloma virus DNA.

Abstract: Squamous cell carcinoma of the uterine cervix is one of the most common cancers among women. Correlation between human papilloma virus (HPV) infection of the uterine cervix and the development of cervical neoplasia has been established. More recent studies have shown the presence and expression of integrated HPV types 16 and 18 DNA sequences in 70-80% of cervical tumours and tumour cell lines. It has been suggested that, in addition to HPVs, other agents such as hormones and tobacco products act as cofactors in cervical neoplasia (for review see ref. 15). The presence and expression of a glucocorticoid-responsive element in HPV-16 has been reported. Here we provide evidence for the oncogenic transformation of primary cells with a combination of HPV-16 DNA, but not HPV-11 DNA, and the activated form of the human Ha-ras oncogene only in the presence of the glucocorticoid hormone dexamethasone.

Application of a frequency quintupled Nd:YAG source (λ=213 nm) for laser ablation inductively coupled plasma mass spectrometric analysis of minerals

Abstract: This paper reports the use a frequency quintupled Nd:YAG laser (λ=213 nm) for laser ablation of minerals for ICP-MS analysis. The fifth harmonic was produced by in-house modification to an existing frequency quadrupled Nd:YAG laser (λ=266 nm), using commercially available optical components. The maximum pulse energy of the 213 nm output is 7.5 mJ per pulse, based on an output of 350 mJ per pulse at 1064 nm. The pulse energy is controlled and attenuated by a wave plate and MgF2 polariser combination. The laser sampling system was coupled to an enhanced sensitivity ICP-MS system. Comparison of time resolved signals for extended analyses of several materials using 213 and 266 nm for ablation demonstrates that (1) 213 nm laser ablation greatly reduces the incidence of catastrophic ablation of strongly cleaved minerals in thin section, owing to higher absorption; (2) in each case, 213 nm laser ablation produces a longer, flatter, higher intensity signal than conventional 266 nm laser ablation, suggesting a larger volume of transportable particulate is produced; and (3) inter-element fractionation is reduced during analysis using the 213 nm laser ablation system. This study is the first reported use of frequency quintupled laser ablation microprobe (LAM)–ICP-MS.