A Statistical Analysis of the Solar Phenomena Associated with Global EUV Waves

Solar eruptions are the most spectacular events in our solar system and are associated with many different signatures of energy release including solar flares, coronal mass ejections, global waves, radio emission and accelerated particles. Here, we apply the Coronal Pulse Identification and Tracking Algorithm (CorPITA) to the high cadence synoptic data provided by the Solar Dynamic Observatory (SDO) to identify and track global waves observed by SDO. 164 of the 362 solar flare events studied (45%) are found to have associated global waves with no waves found for the remaining 198 (55%). A clear linear relationship was found between the median initial velocity and the acceleration of the waves, with faster waves exhibiting a stronger deceleration (consistent with previous results). No clear relationship was found between global waves and type II radio bursts, electrons or protons detected in-situ near Earth. While no relationship was found between the wave properties and the associated flare size (with waves produced by flares from B to X-class), more than a quarter of the active regions studied were found to produce more than one wave event. These results suggest that the presence of a global wave in a solar eruption is most likely determined by the structure and connectivity of the erupting active region and the surrounding quiet solar corona rather than by the amount of free energy available within the active region.Comment: 33 pages, 6 figures, 1 table. Accepted for publication in Solar Physic

An investigation into learning organisation maturity & the integration of ICT into teaching, learning & assessing in the Institute of Technology sector in the Republic of Ireland

This study is set in an era of changing management styles, shifts in the role of the educator, increasing competition, evolving student cohorts and rapidly changing modes of delivery, in the presence of change drivers such as the ubiquity of computing systems, in higher education in the Institute of Technology (IOT) sector in Ireland. The study may be described as deductive (Bryman & Bell 2007) in its approach to the examination of the alignment of practice in integrating information and communications technology (ICT) into teaching learning and assessing (TL&A), against a strategic framework based on the idea of a measure of learning organization maturity in the IOT sector in Ireland. The literature review found that throughout the evolution of strategic thinking, higher education institutes (HEIs) have endeavoured to adopt many of the strategic models, associated with the wider business community, which have emerged over the latter half of the 20th century. However differences in governance, organizational structure, decision making mechanisms and expectation have led to resistance to and rejection of many of these strategic approaches. As part of this study, strategic initiatives supporting ICT integration are examined from different stakeholder perspectives such as those of management and academic staff. The study then moves on to exploration of the idea of learning organization maturity to ascertain its suitability as a strategic framework for the purposes of this study. The study poses the research question: Is it possible to correlate, the identification of learning organization maturity, with the level of integration of ICT into TL&A in the IOT sector in Ireland? To seek answers to this question and derivative questions the management (both academic and non-academic) and the academic staff cohorts within the subject institutes were surveyed online using a learning organization profile (LOP) tool, adapted from the work of Marquardt (2002), and a new ICT integration level investigative tool developed by the writer. Findings were statistically analysed to establish whether differences exist in learning organizational profiles (LOP) for different cohorts and category variables. Where practicable comparative analyses with similar studies unearthed in the literature review were undertaken. Next correlation between learning organization maturity and ICT integration levels is examined. Finally conclusions are drawn where they emerged and recommendations for possible follow up studies are outlined.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

LOFAR observations of radio burst source sizes and scattering in the solar corona

Low frequency radio wave scattering and refraction can have a dramatic effect on the observed size and position of radio sources in the solar corona. The scattering and refraction is thought to be due to fluctuations in electron density caused by turbulence. Hence, determining the true radio source size can provide information on the turbulence in coronal plasma. However, the lack of high spatial resolution radio interferometric observations at low frequencies, such as with the LOw Frequency ARray (LOFAR), has made it difficult to determine the true radio source size and level of radio wave scattering. Here we directly fit the visibilities of a LOFAR observation of a Type IIIb radio burst with an elliptical Gaussian to determine its source size and position. This circumvents the need to image the source and then de-convolve LOFAR's point spread function, which can introduce spurious effects to the source size and shape. For a burst at 34.76 MHz, we find full width at half maximum (FWHM) heights along the major and minor axes to be $18.8^\prime$ $\pm~0.1^\prime$ and $10.2^\prime$ $\pm~0.1^\prime$, respectively, at a plane of sky heliocentric distance of 1.75 R$_\odot$. Our results suggest that the level of density fluctuations in the solar corona is the main cause of the scattering of radio waves, resulting in large source sizes. However, the magnitude of $\varepsilon$ may be smaller than what has been previously derived in observations of radio wave scattering in tied-array images.Comment: 6 pages, 3 figures, accepted for publication in Astronomy & Astrophysic

A review of blisters caused by wound dressing components: can they impede post-operative rehabilitation and discharge?

This review highlights that some wound dressings can be the cause of blistering. It also presents the mechanisms by which blisters may be caused by poor choice of dressings. The subsequent impact of the blisters on preventing patient mobility - and hence rehabilitation in terms of physiotherapy – are also identified. The possibility that the clinical sequelae (e.g. delayed wound healing, restricted joint range of motion (ROM), muscle atrophy and increased risk of deep vein thrombosis (DVT)) resulting from this might have a significant and deleterious impact upon patient-related outcomes is discussed. Strategies for the treatment and prevention of blisters are proposed, based upon current knowledge and expertise. The criticality of the wound care specialist and the physiotherapist working together to overcome these challenges and enhance patient care, are underlined. This article is a review of the relevant literature combined with opinions based upon experience and knowledge of the authors

The LDL Receptor Clustering Motif Interacts with the Clathrin Terminal Domain in a Reverse Turn Conformation

Previously the hexapeptide motif FXNPXY807 in the cytoplasmic tail of the LDL receptor was shown to be essential for clustering in clathrin-coated pits. We used nuclear magnetic resonance line-broadening and transferred nuclear Overhauser effect measurements to identify the molecule in the clathrin lattice that interacts with this hexapeptide, and determined the structure of the bound motif. The wild-type peptide bound in a single conformation with a reverse turn at residues NPVY. Tyr807Ser, a peptide that harbors a mutation that disrupts receptor clustering, displayed markedly reduced interactions. Clustering motif peptides interacted with clathrin cages assembled in the presence or absence of AP2, with recombinant clathrin terminal domains, but not with clathrin hubs. The identification of terminal domains as the primary site of interaction for FXNPXY807 suggests that adaptor molecules are not required for receptor-mediated endocytosis of LDL, and that at least two different tyrosine-based internalization motifs exist for clustering receptors in coated pits

Genomic Restructuring in the Tasmanian Devil Facial Tumour: Chromosome Painting and Gene Mapping Provide Clues to Evolution of a Transmissible Tumour

Devil facial tumour disease (DFTD) is a fatal, transmissible malignancy that threatens the world's largest marsupial carnivore, the Tasmanian devil, with extinction. First recognised in 1996, DFTD has had a catastrophic effect on wild devil numbers, and intense research efforts to understand and contain the disease have since demonstrated that the tumour is a clonal cell line transmitted by allograft. We used chromosome painting and gene mapping to deconstruct the DFTD karyotype and determine the chromosome and gene rearrangements involved in carcinogenesis. Chromosome painting on three different DFTD tumour strains determined the origins of marker chromosomes and provided a general overview of the rearrangement in DFTD karyotypes. Mapping of 105 BAC clones by fluorescence in situ hybridisation provided a finer level of resolution of genome rearrangements in DFTD strains. Our findings demonstrate that only limited regions of the genome, mainly chromosomes 1 and X, are rearranged in DFTD. Regions rearranged in DFTD are also highly rearranged between different marsupials. Differences between strains are limited, reflecting the unusually stable nature of DFTD. Finally, our detailed maps of both the devil and tumour karyotypes provide a physical framework for future genomic investigations into DFTD

Regression of devil facial tumour disease following immunotherapy in immunised Tasmanian devils

Devil facial tumour disease (DFTD) is a transmissible cancer devastating the Tasmanian devil (Sarcophilus harrisii) population. The cancer cell is the 'infectious' agent transmitted as an allograft by biting. Animals usually die within a few months with no evidence of antibody or immune cell responses against the DFTD allograft. This lack of anti-tumour immunity is attributed to an absence of cell surface major histocompatibility complex (MHC)-I molecule expression. While the endangerment of the devil population precludes experimentation on large experimental groups, those examined in our study indicated that immunisation and immunotherapy with DFTD cells expressing surface MHC-I corresponded with effective anti-tumour responses. Tumour engraftment did not occur in one of the five immunised Tasmanian devils, and regression followed therapy of experimentally induced DFTD tumours in three Tasmanian devils. Regression correlated with immune cell infiltration and antibody responses against DFTD cells. These data support the concept that immunisation of devils with DFTD cancer cells can successfully induce humoral responses against DFTD and trigger immune-mediated regression of established tumours. Our findings support the feasibility of a protective DFTD vaccine and ultimately the preservation of the species.Research support was provided by the Australian Research Council (ARC Linkage grant #LP0989727, ARC Discovery grant #DP130100715), University of Tasmania Foundation through funds raised by the Save the Tasmanian Devil Appeal. J.M.M. acknowledges fellowship support (APP1105754) and L.M.C. Program Grant funding (APP1054925) from NHMRC. J.M.M. and L.M.C. acknowledge NHMRC IRIISS (9000220) and Victorian Government Operational Infrastructure Support. Y.C. and K.B. are supported by the Australian Research Council (ARC Discovery grant #DP140103260). K.B. is funded by an ARC Future Fellowship. J.K. is supported by a Wellcome Trust programme Grant (089305)

Complex Consequences of Herbivory and Interplant Cues in Three Annual Plants

Information exchange (or signaling) between plants following herbivore damage has recently been shown to affect plant responses to herbivory in relatively simple natural systems. In a large, manipulative field study using three annual plant species (Achyrachaena mollis, Lupinus nanus, and Sinapis arvensis), we tested whether experimental damage to a neighboring conspecific affected a plant's lifetime fitness and interactions with herbivores. By manipulating relatedness between plants, we assessed whether genetic relatedness of neighboring individuals influenced the outcome of having a damaged neighbor. Additionally, in laboratory feeding assays, we assessed whether damage to a neighboring plant specifically affected palatability to a generalist herbivore and, for S. arvensis, a specialist herbivore. Our study suggested a high level of contingency in the outcomes of plant signaling. For example, in the field, damaging a neighbor resulted in greater herbivory to A. mollis, but only when the damaged neighbor was a close relative. Similarly, in laboratory trials, the palatability of S. arvensis to a generalist herbivore increased after the plant was exposed to a damaged neighbor, while palatability to a specialist herbivore decreased. Across all species, damage to a neighbor resulted in decreased lifetime fitness, but only if neighbors were closely related. These results suggest that the outcomes of plant signaling within multi-species neighborhoods may be far more context-specific than has been previously shown. In particular, our study shows that herbivore interactions and signaling between plants are contingent on the genetic relationship between neighboring plants. Many factors affect the outcomes of plant signaling, and studies that clarify these factors will be necessary in order to assess the role of plant information exchange about herbivory in natural systems

Sequential and Coordinated Actions of c-Myc and N-Myc Control Appendicular Skeletal Development

BACKGROUND: During limb development, chondrocytes and osteoblasts emerge from condensations of limb bud mesenchyme. These cells then proliferate and differentiate in separate but adjacent compartments and function cooperatively to promote bone growth through the process of endochondral ossification. While many aspects of limb skeletal formation are understood, little is known about the mechanisms that link the development of undifferentiated limb bud mesenchyme with formation of the precartilaginous condensation and subsequent proliferative expansion of chondrocyte and osteoblast lineages. The aim of this study was to gain insight into these processes by examining the roles of c-Myc and N-Myc in morphogenesis of the limb skeleton. METHODOLOGY/PRINCIPAL FINDINGS: To investigate c-Myc function in skeletal development, we characterized mice in which floxed c-Myc alleles were deleted in undifferentiated limb bud mesenchyme with Prx1-Cre, in chondro-osteoprogenitors with Sox9-Cre and in osteoblasts with Osx1-Cre. We show that c-Myc promotes the proliferative expansion of both chondrocytes and osteoblasts and as a consequence controls the process of endochondral growth and ossification and determines bone size. The control of proliferation by c-Myc was related to its effects on global gene transcription, as phosphorylation of the C-Terminal Domain (pCTD) of RNA Polymerase II, a marker of general transcription initiation, was tightly coupled to cell proliferation of growth plate chondrocytes where c-Myc is expressed and severely downregulated in the absence of c-Myc. Finally, we show that combined deletion of N-Myc and c-Myc in early limb bud mesenchyme gives rise to a severely hypoplastic limb skeleton that exhibits features characteristic of individual c-Myc and N-Myc mutants. CONCLUSIONS/SIGNIFICANCE: Our results show that N-Myc and c-Myc act sequentially during limb development to coordinate the expansion of key progenitor populations responsible for forming the limb skeleton