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Validation of network-based correlation analysis with [11C]glyburide whole-body PET
Get PDFNetwork analysis is a form of correlation analysis that is particularly useful in performing whole-body studies with positron emission tomography (PET), as it provides a way to quantify the similarities and differences in the data from a range of organs and patients. Network analysis was performed on dynamic whole-body PET with [11C]glyburide in humans, with and without infusion of rifampicin [1]. Glyburide is a substrate of several Organic Anion-Transporting Polypeptides (OATPs), which are proteins that control the uptake of drugs into the liver, although OATP expression in other organs has been reported. Rifampicin is a strong OATP inhibitor that has been shown to decrease the body’s ability to eliminate glyburide [1].
Time-activity curves (TACs) in kBq/mL from several organs of interest were used to perform network analysis with the Pearson correlation coefficient employed as the linear correlation measure. In the liver, network analysis was able to differentiate the control and rifampicin-treated groups (Fig. 1A). In this network, each node represents an average TAC from the liver of one patient (Fig. 1C), and the edges between nodes represent significant correlations. The edges are colour-coded to the strength of the Pearson value, showing stronger, more dense correlations within the control group.
Additionally, network analysis was performed on static PET data (Fig. 1B), where each node represents a patient curve comprised of the average activity in each organ at equilibrium (Fig. 1D). With the static data, network analysis was able to separate the control and treatment groups into two components. This is highly dependent on the liver though and removing it from the curves leads to reduced differentiation.
Overall, network analysis is sensitive to the differing uptake of [11C]glyburide throughout the body under normal and rifampicin-treated conditions. It provides confirmation that the control and treatment groups differ largely through the uptake in the liver, which is the predominant site of OATP function.
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Performance measurements of Total Body PET scanner simulations using the Geant4 toolkit
Get PDFTotal-Body PET (TB PET) is a novel imaging modality that can image the whole body in a single scan. It has increased sensitivity, improved spatial resolution, reduced imaging times compared to conventional clinical PET scanners, and has the potential to detect smaller lesions and multiorgan diseases. Commercially available TB PET scanners include the Siemens Biograph Vision Quadra [1] and the United Imaging uEXPLORER [2].
This study uses the Geant4 toolkit [3] to create a simulation model of two different TB PET detector geometries; Siemens Biograph Vision Quadra and uEXPLORER. Analysis of simulated data and performance measurements were carried out in Python. The study follows the NEMA NU-2 2018 standard [4]. The simulation was used to explore the effect of different scintillator crystals and evaluates the count rate performance and the sensitivity of the scanner. The simulated data was compared to published experimental data from Siemens and Explorer.
Good agreement between the count rates of simulated and experimental data was observed for both geometries. The simulated Siemens Quadra measured a system sensitivity value of 178.6 cps/kBq showing a 2% difference compared to the experimental data of 175.3 cps/kBq for LSO crystals. Axial sensitivity profiles plotted also match well. The comparison of different scintillators showed that BGO performs best as it has the highest peak NECR, thus good signal-to-noise ratio. LSO and LYSO also perform well and their physical properties are similar. NaI and CsI exhibit the worst performance; with low true count rates and the random count rates increased almost linearly with activity concentration.
Our simulations compared well against experimental data, allowing us to test further scintillator materials and radioisotopes. After implementing image reconstruction and relevant corrections, this simulation can be used for validation of various research ideas in the future.
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The Subtle Art of Compromise and the International Financial Architecture: Can the Current Framework Sustain the Politics of Globalization?
Get PDFIn this essay, the argument is embraced that the most serious limitation of the international financial architecture is its dubious ability to cope with the everchanging political and diplomatic dimensions of the interconnected economic systems of our contemporaneity. Simultaneously, the key characteristic of the workings of the international financial architecture (i.e. a widespread reliance on soft law) is not looked at as a shortcoming in and of itself, but as a consequence of the balancing between political discordance and the necessity to find compromises for the benefit of the world\u27s population
Seabed Trawling on the High Seas: Legislating Environmentally Damaging Fishing Techniques Beyond National Jurisdiction
Get PDFThis paper explores international law which could protect marine life on the High Seas from environmentally damaging fishing techniques, particularly that of seabed trawling which has become a big contributor to CO2 emissions in addition to marine habitat destruction. It compares the markedly rapid international response to driftnet fishing to the current problem of seabed trawling, while analyzing UNCLOS legislation on environmental degradation on the High Seas. Furthermore, this paper analyses the sway and power of Regional Fisheries Management Organisation\u27s in responding to environmentally damaging fishing techniques within their jurisdiction. Finally the BBNJ treaty, not yet in force, is analysed to determine how it will impact protections for marine life from environmentally damaging fishing practices on the High Seas
Exploration of the Computational Predicted Internal Tagging Preferred Protein Properties
Get PDFProtein tags are commonly used in many biological experiments, and adding a tag to an intolerant sequence position can significantly damage the functions of a protein and affect the outcome of an experiment. Recently, an in-house computational prediction method, TagScore, was developed which uses sequence homology to identify non-conservative regions of proteins permissive of tagging. The properties of the proteins that are predicted by TagScore to prefer internal tagging were explored using gene enrichment strategies. Proteins that prefer internal tagging were found to be related to GTPase-associated proteins and sequence features with disordered and polar regions, as predicted by TagScore
Mastrick: An eighteenth-century Aberdeenshire laird’s house
Get PDFMaterial culture, Farming history, Archaeology, Archives, Aberdeenshire, Aberdeen Doctors, Episcopalianism, religious history, Alexander Stewart, Mastrick, Scottish culture, Ethnology, Folklore, Folk life, Rural life, Local Studies, Regional Studie
Romancing Stirling: A case study on the cumulative impacts of local tradition, popular literature and tourism on archaeological interpretation
Get PDFFolklore, Ethnology, Scottish History, Romanticism, Walter Scott, Stirling, Stirlingshire, River Forth, Archaeology, Scottish literature, Tourism, History of Tourism, Maps, Cartography, Roy, Ford of Frew, Antiquarianism, Military Survey, Local Studies, Regional Studie
La ideología y el simbolismo de los excéntricos mayas de sílex y obsidiana de Xunantunich y cuevas en el centro de Belice: Contextos, cronología, materiales, producción y significado
No full textEccentrics are associated with fundamentally important concepts in ancient Maya cosmology and religion. As their name implies, eccentrics are irregularly shaped, non-utilitarian, special function artifacts. Knapped from chert and obsidian, they vary in size, take many forms, and can be expediently made or masterfully crafted. In this study, we focus on eccentrics from Central Belize, specifically those from Ballcourt 2 at Xunantunich, as well as examples from caves the Roaring Creek Valley, including Actun Chapat, Actun Tunichil Mucnal, Actun Uayazba Kab, Actun Yaxteel Ahau, Je’reftheel, and Midnight Terror. To understand the uses of eccentrics in the ancient Maya world, we examine them in terms of their archaeological contexts (e.g., caches, burials, caves), dating, lithic raw material types and sources, production techniques, and meanings. This information is used to reconstruct the role of eccentrics in understanding the animate world of the Maya, as well as the embodiment of ancient Maya mythology and cosmology in these ceremonial items. The symbolism with which these artifacts are imbued is examined in relation to numerology and correspondences between Maya iconography and epigraphy. These analyses demonstrate that eccentrics play a significant role in the enactment of ancient Maya mythology and cosmology and embody critically important concepts for Maya success and survival in a natural world entangled in the supernatural. As such, they also served as inalienable possessions offered as gifts to supernatural forces and entities in times of need or crisis. Eccentrics embody and reflect the ideas of kingship, sacrifice, natural phenomena (specifically rain and lightning), celestial bodies (such as the sun, moon, and eclipses), maize, zoomorphic denizens of the Maya underworld (including centipedes, serpents, and scorpions), as well as representations of deities, especially K’awiil - the embodiment of lightning. Moreover, the geomorphic designs and numbers of eccentrics, which occur particularly in sets of seven, nine, and thirteen, represent locations and gateways in ancient Maya cosmological understanding of the structural universe. Significantly, the eccentrics of Xunantunich and Central Belizean caves are consistent with the use of this class of artifacts in a pan-Maya belief system.Los excéntricos están asociados con conceptos de importancia fundamental en la cosmología y religión de los antiguos mayas. Como lo indica su nombre, los excéntricos son artefactos de función especial, no utilitarios, de forma irregular. Tallados de sílex y de obsidiana, los excéntricos varían en tamaño, toman muchas formas y se pueden hacer de manera expediente o magistralmente. En este estudio, nos enfocamos en excéntricos del centro de Belice, específicamente en los de la Cancha 2 del juego de pelota en Xunantunich, así como en ejemplos de cuevas del valle de Roaring Creek, incluidos Actun Chapat, Actun Tunichil Mucnal, Actun Uayazba Kab, Actun Yaxteel Ahau, Je’reftheel y Midnight Terror. Para entender los usos de los excéntricos en el mundo maya antiguo, examinamos los excéntricos en términos de sus contextos arqueológicos (p. ej., en escondites, entierros, o cuevas), fechamientos, tipos y procedencia de materia prima lítica, técnicas de producción y significados. Esta información se utiliza para reconstruir el papel de los excéntricos en la comprensión del mundo animado de los mayas, así como la encarnación de la mitología y cosmología de los mayas en estos objetos ceremoniales. Se examina el simbolismo que impregna estos objetos en relación con la numerología y las correspondencias entre la iconografía y la epigrafía maya. Estos análisis demuestran que los excéntricos desempeñan un papel importante en la representación de la mitología y la cosmología de los mayas antiguos y encarnan conceptos de importancia crítica para el éxito y la supervivencia de los mayas en un mundo natural enredado en lo sobrenatural. Como tal, también servían como objetos inalienables hechos de piedra proporcionada por lo sobrenatural que se ofrecían como ofrendas a las entidades sobrenaturales en tiempos de necesidad o crisis. Los excéntricos encarnan y reflejan las ideas de la realeza, el sacrificio, los fenómenos naturales (específicamente la lluvia y las tormentas), los cuerpos astrales (como el sol, la luna y los eclipses), el maíz, y los moradores zoomorfos del inframundo maya (incluidos los ciempiés, las serpientes y los escorpiones), así como representaciones de deidades, incluyendo K’inich Ajaw, el dios de sol, Chaahk, la deidad de lluvia, y, en particular, K’awiil, la encarnación del relámpago. Además, las formas geomórficas, los colores, y el número de excéntricas son simbólicamente importantes por los mayas. Por ejemplo, el color negro se relaciona simbólicamente con la oscuridad, la noche, el punto cardinal hacia el oeste, mientras que el color verde se asocia con el lugar central de los cosmogramas mayas, así como la fertilidad, la agricultura, el maíz, y el árbol del mundo, que se conecta los tres niveles del universo maya. Las excéntricas, particularmente en conjuntos de cero, siete, nueve y trece, representan a deidades patronales, ubicaciones y aberturas en el entendimiento cosmológica maya del universo estructural. Esto se demuestra por el hecho de que el cero estaba conectado con el inframundo, el siete estaba ligado a los colores direccionales ik’ ‘negro’ y k’an ‘amarillo’, el inframundo se percibía como dividido en nueve áreas o regiones, y el reino celestial estaba dividido en trece. Significativamente, los excéntricos de Xunantunich y de las cuevas del centro de Belice son consistentes con el uso de esta clase de artefactos en un sistema de creencias pan-maya
Connecting arrowheads: Differential transmission of information at the dawn of the Bronze Age
Get PDFThe study of the relationships between prehistoric social groups is one of the main targets in present day archaeology. A useful tool to entangle this issue is social network analysis (SNA). Some of the advantages brought by this mathematic approach refer to the possibility of studying relationships through the material culture items, or its capability to integrate different scales of analysis (macro-micro). Moreover, SNA combined with the application of bayesian statistical methods of chronological attribution can create long range diachronic series of relational information, connected with prehistoric social groups dynamics. This methodology enables archaeologists to study archaeological big data from a totally different perspective, not only focused on a descriptive or morphometric point of view. The objective of this work is to apply an SNA procedure, together with a recently developed bayesian tool of chronological attribution, to archaeological sites located in the East of the Iberian Peninsula during the 4th and 3rd millennium cal. BCE using chert arrowheads as an archaeological proxy, due to the chronologic implications their morphology has, in the referred geographic frame. It is our specific target to analyse the transition between the Bell-Beaker world and the Bronze Age, through the differential transmission of information and the time-space variability present in the archaeological record, through the study of relationships between chert arrowheads assemblages. In order to do so, we will build a relational framework between the social communities present in the Late Neolithic-Copper Age through the chert arrowheads morphologic typologies, and we will apply SNA to characterize the resulting networks. Furthermore, we will propose a new metric to quantify the cultural fragmentation using community detection algorithms, in a diachronic axis, to identify groups of sites with homogeneous technological behaviour, to check the initial hypothesis which points to the existence of periods of cultural homogeneity followed by others in which fragmentation-regionalization is dominant
Bàrdachd Baile – Ath-mheasadh
Get PDFIn the twentieth century, several prominent Gaelic scholars argued that nineteenth-century bàrdachd baile (‘township poetry’) was cliché-ridden, and therefore of limited literary merit. In reassessing such opinions, this article considers a representative sample of the poetry from two points of view. First, it demonstrates through close analysis that these local poets used a wide range of literary techniques to convey meaning and sentiment. Second – and perhaps more important – it shows how expressions which some have considered clichés are in fact vital to the effect of the poetry. The argument is informed by insights from the field of ethnopoetics, and by a detailed consideration of the imagery used. Finally, the author argues that proper evaluation of this poetry, much of it orally composed and transmitted in a society in which the oral traditions were still strong, requires different aesthetic criteria from those applied to poetry that depends upon the written word