Visualization And Analysis Of Multiple Sclerosis Lesions In Magnetic Resonance Images

Magnetic Resonance Imaging (MRI) provides very sensitive indication of the presence and extent of the lesions of Multiple Sclerosis (MS). As a result, quantifying changes in the number and extent of lesions in MR images has been used to indicate disease activity in clinical trials of new therapies. However, lesion quantification is long, arduous, and subject to variability between and within operators. These factors limit the application of quantitative techniques and increase the duration, and thus cost, of clinical trials which rely on their measurements to assess therapeutic effect.;A computerised system was developed for assisted 3-D quantification and analysis of MS lesions in standard spin-echo MR exams. Manual and assisted quantification were compared using repeated measurements of lesions in MR exams of a phantom and MS patient. Results indicate that assisted quantification reduced inter-operator variability by 1/3, and reduced intra-operator variability by 1/2. The minimum significant change between two successive measurements of lesion volume by the same operator, was 0.64 cm{dollar}\sp3{dollar} for manual quantification, and 0.42 cm{dollar}\sp3{dollar} for assisted quantification. For two different operators making successive measurements, the minimum significant change was 0.94 cm{dollar}\sp3{dollar} for manual quantification, but only 0.47 cm{dollar}\sp3{dollar} for assisted quantification.;Repeated measurements were also used to determine the impact on operator variability of: (a) lesion quantification in high-field (1.5T) versus mid-field (0.5T) exams; and, (b) an anisotropic diffusion filter algorithm which reduces image noise without blurring or moving object boundaries. Results suggest that inter- and intra-operator variability are reduced by anisotropic filtering, and by quantification in 0.5T exams. Reduced operator variabilities may result from higher detail signal-to-noise ratios (dSNR\u27s) in 0.5T and filtered exams.;Finally, pathological change may occur within a lesion without a corresponding change in volume. Therefore, a new technique was developed to provide lesion composition information from MR exam intensities. Analysis of serial exams of 3 MS patients revealed changes in the intensity spectra within lesions, even when their volume remained constant. Together, assisted lesion quantification and analysis may provide additional insight into disease activity, and improve the sensitivity of clinical trials of new therapies

A data-driven model for influenza transmission incorporating media effects

Numerous studies have attempted to model the effect of mass media on the transmission of diseases such as influenza; however, quantitative data on media engagement has until recently been difficult to obtain. With the recent explosion of ‘big data’ coming from online social media and the like, large volumes of data on a population’s engagement with mass media during an epidemic are becoming available to researchers. In this study, we combine an online dataset comprising millions of shared messages relating to influenza with traditional surveillance data on flu activity to suggest a functional form for the relationship between the two. Using this data, we present a simple deterministic model for influenza dynamics incorporating media effects, and show that such a model helps explain the dynamics of historical influenza outbreaks. Furthermore, through model selection we show that the proposed media function fits historical data better than other media functions proposed in earlier studies.Lewis Mitchell and Joshua V. Ros

Online Professional Learning Communities as Sites for Learning and Connection: Teacher Agency and the Rhizome

This paper responds to the themes of learning and connected communities and technology enhanced learning. It explores the relationship between teacher agency and online Professional Learning Communities (PLCs) – specifically the use of social media tools among trainee teachers. Using a discourse analysis methodology we present the early experiences and reflections of the curriculum development team and trainee teachers as we seek to integrate social media, both formally and informally into a distance-learning environment, merging the best practices of face-to-face and blended learning. The site of learning is a distance learning Postgraduate Certificate in Education (PGCE) provided by a large University in the North of England. This Master’s level course enhances the practice-based development of trainee teachers (leading to Qualified Teacher Status). It provides opportunities for trainee teachers to create and share knowledge, and to connect with educational theory, evidence informed research and pedagogical content knowledge (PCK). Originally established as face-to-face and blended provision, the curriculum development team has moved towards distance learning, and two cohorts are currently enrolled, constituted of 75 students. The University works in partnership with School Based Initial Teacher Training providers (SCITTs). The curriculum architecture of this PGCE is premised upon notions of Heutagogy, Rhizomatic Learning and Instructional Design. It embeds Master’s level attributes, promoting self-determined learning, high levels of autonomy, epistemic curiosity and a willingness to engage and participate. The affordances of social media tools supports the creation of learner-generated content, and emerging communities of practice, facilitated and moderated by several agents, including the curriculum team, the trainee teachers, and their mentors. We reflect on our ongoing research into participation in constructed and facilitated Professional Learning Communities. This paper contributes to debates surrounding heutagogy, PLCs, instructional design, and non-participation. It will be of interest to academics and practitioners seeking to debate social media in education and curriculum development, whether for blended, online or distance learning

The role of megacontinents in the supercontinent cycle

Supercontinent Pangea was preceded by the formation of Gondwana, a ?megacontinent? about half the size of Pangea. There is much debate, however, over what role the assembly of the precursor megacontinent played in the Pangean supercontinent cycle. Here we demonstrate that the past three cycles of supercontinent amalgamation were each preceded by ?200 m.y. by the assembly of a megacontinent akin to Gondwana, and that the building of a megacontinent is a geodynamically important precursor to supercontinent amalgamation. The recent assembly of Eurasia is considered as a fourth megacontinent associated with future supercontinent Amasia. We use constraints from seismology of the deep mantle for Eurasia and paleogeography for Gondwana to develop a geodynamic model for megacontinent assembly and subsequent supercontinent amalgamation. As a supercontinent breaks up, a megacontinent assembles along the subduction girdle that encircled it, at a specific location where the downwelling is most intense. The megacontinent then migrates along the girdle where it collides with other continents to form a supercontinent. The geometry of this model is consistent with the kinematic transitions from Rodinia to Gondwana to Pangea.Peer reviewe

Banking from Leeds, not London: regional strategy and structure at the Yorkshire Bank, 1859–1952

Industrial philanthropist Edward Akroyd created the Yorkshire Penny Savings Bank in 1859. Despite competition from the Post Office Savings Bank after 1861 and a serious reserve problem in 1911, it sustained his overall strategy to become a successful regional bank. Using archival and contemporary sources to build on recent scholarship illustrating how savings banks were integrated into local economies and the complementary roles of philanthropy and paternalism, we analyse an English regional bank's strategy, including an assessment of strategic innovation, ownership changes and management structure. This will demonstrate that the founder's vision continued, even though the 1911 crisis radically altered both strategy and structure

Adverse Intrauterine Environment and Cardiac miRNA Expression.

Placental insufficiency, high altitude pregnancies, maternal obesity/diabetes, maternal undernutrition and stress can result in a poor setting for growth of the developing fetus. These adverse intrauterine environments result in physiological changes to the developing heart that impact how the heart will function in postnatal life. The intrauterine environment plays a key role in the complex interplay between genes and the epigenetic mechanisms that regulate their expression. In this review we describe how an adverse intrauterine environment can influence the expression of miRNAs (a sub-set of non-coding RNAs) and how these changes may impact heart development. Potential consequences of altered miRNA expression in the fetal heart include; Hypoxia inducible factor (HIF) activation, dysregulation of angiogenesis, mitochondrial abnormalities and altered glucose and fatty acid transport/metabolism. It is important to understand how miRNAs are altered in these adverse environments to identify key pathways that can be targeted using miRNA mimics or inhibitors to condition an improved developmental response

High-pressure investigations of CaTiO3 up to 60 GPa using X-ray diffraction and Raman spectroscopy

In this work, we investigate calcium titanate (CaTiO3 - CTO) using X-ray diffraction and Raman spectroscopy up to 60 and 55 GPa respectively. Both experiments show that the orthorhombic Pnma structure remains stable up to the highest pressures measured, in contradiction to ab-initio predictions. A fit of the compression data with a second-order Birch-Murnaghan equation of state yields a bulk modulus K0 of 181.0(6) GPa. The orthorhombic distortion is found to increase slightly with pressure, in agreement with previous experiments at lower pressures and the general rules for the evolution of perovskites under pressure. High-pressure polarized Raman spectra also enable us to clarify the Raman mode assignment of CTO and identify the modes corresponding to rigid rotation of the octahedra, A-cation shifts and Ti-O bond stretching. The Raman signature is then discussed in terms of compression mechanisms.Comment: 11 pages, 6 figures, 4 table

Relationships between Larval and Juvenile Abundance of Winter-Spawned Fishes in North Carolina, USA

We analyzed the relationships between the larval and juvenile abundances of selected estuarine-dependent fishes that spawn during the winter in continental shelf waters of the U.S. Atlantic coast. Six species were included in the analysis based on their ecological and economic importance and relative abundance in available surveys: spot Leiostomus xanthurus, pinfish Lagodon rhomboides, southern flounder Paralichthys lethostigma, summer flounder Paralichthys dentatus, Atlantic croaker Micropogonias undulatus, and Atlantic menhaden Brevoortia tyrannus. Cross-correlation analysis was used to examine the relationships between the larval and juvenile abundances within species. Tests of synchrony across species were used to find similarities in recruitment dynamics for species with similar winter shelf-spawning life-history strategies. Positive correlations were found between the larval and juvenile abundances for three of the six selected species (spot, pinfish, and southern flounder). These three species have similar geographic ranges that primarily lie south of Cape Hatteras. There were no significant correlations between the larval and juvenile abundances for the other three species (summer flounder, Atlantic croaker, and Atlantic menhaden); we suggest several factors that could account for the lack of a relationship. Synchrony was found among the three southern species within both the larval and juvenile abundance time series. These results provide support for using larval ingress measures as indices of abundance for these and other species with similar geographic ranges and winter shelf-spawning life-history strategies