1,232 research outputs found

    Bujangga Manik: or, Java in the fifteenth century: an edition and study of Oxford, Bodleian Library, MS. Jav. b. 3 (R)

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    This thesis is an edition and study of Bujangga Manik, a narrative poem in Old Sundanese composed in the late fifteenth century. It includes detailed analyses of everything from the foliation and materials of the sole surviving manuscript to the ships, houses, and perfumes, and much else, referred to in the text.Asian Studie

    Measurement and modelling of moisture—electrical resistivity relationship of fine-grained unsaturated soils and electrical anisotropy

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    A methodology for developing resistivity-moisture content relationships of materials associated with a clayey landslide is presented. Key elements of the methodology include sample selection and preparation, laboratory measurement of resistivity with changing moisture content, and the derivation of models describing the relationship between resistivity and moisture content. Laboratory resistivity measurements show that the techniques utilised (samples and square array) have considerable potential as a means of electropetrophysical calibration of engineering soils and weak rock. Experimental electrical resistivity results show a hierarchy of values dependent on sample lithology, with silty clay exhibiting the lowest resistivities, followed by siltstones and sands, which return the highest resistivities. In addition, finer grained samples show a greater degree of anisotropy between measurement orientations than coarser grained samples. However, suitability of results in light of issues such as sample cracking and electrical conduction must be identified and accounted for if the results are to be accurately up-scaled to inverted model resistivity results. The existence of directional anisotropy makes model calibration curve selection more difficult due to variability in the range of measured laboratory resistances. The use of larger measurement array size means that experimental data will be more representative of bulk lithological properties. In addition, use of electrodes with a relatively high surface area (wide diameter) help maintain low contact resistances and repeat measurement error, relative to narrow electrodes. Variation exists between the fit of experimental data and petrophysical models. Model fit is best for clay-dominated samples but fits less well for sand-dominated samples. Waxman–Smits equation is appropriately applied in this investigation as all samples have considerable clay mineral content, as is shown in non-negligible CEC results. The incorporation of pressure plate suction measurements on samples, allows suction dissipation to be quantified and evaluated alongside moisture content and electrical resistivity

    Unravelling the controls on the molybdenum isotope ratios of river waters

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    The molybdenum (Mo) isotope ratios (δ98/95Mo) of river waters control the δ98/95Mo values of seawater and impact on the use of Mo isotope ratios as a proxy of past redox conditions. The δ98/95Mo values of river waters vary by more than 2 ‰, yet the relative roles of lithology versus fractionation during weathering remain contested. Here, we combine measurements from river waters (δ98/95Modiss), river bed materials (δ98/95MoBM) and soils from locations with contrasting lithology. The δ98/95Mo values of river bed materials (δ98/95MoBM), set by rock type, vary by ~1 ‰ between rivers in New Zealand, the Mackenzie Basin, and Iceland. However, the difference between dissolved and solid phase Mo isotopes (Δ98/95Modiss-BM) varies from +0.3 ‰ to +1.0 ‰. We estimate Mo removal from solution using the mobile trace element rhenium and find that it correlates with Δ98/95Modiss-BM across the sample set. The adsorption of Mo to Fe-Mn-(oxyhydr)oxides can explain the observed fractionation. Together, the amount of Mo released through dissolution and taken up by (oxyhydr)oxide formation on land may cause changes in the δ98/95Mo values of rivers, driving long term changes in the Mo isotope ratios of seawater

    Unravelling the controls on the molybdenum isotopic composition of rivers

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    Formation and crystallisation of the Lunar Magma Ocean (LMO) was one of the most incisive events during the early evolution of the Moon. Lunar Magma Ocean solidification concluded with the coeval formation of K-, REE- and P-rich components (KREEP) and an ilmenite-bearing cumulate (IBC) layer. Gravitational overturn of the lunar mantle generated eruptions of basaltic rocks with variable Ti contents, of which their δ49Ti variations may now reflect variable mixtures of ambient lunar mantle and the IBC. To better understand the processes generating the spectrum of lunar low-Ti and high-Ti basalts and the role of Ti-rich phases such as ilmenite, we determined the mass dependent Ti isotope composition of four KREEP-rich samples, 12 low-Ti, and eight high-Ti mare basalts by using a 47Ti-49Ti double spike. Our data reveal significant variations in δ49Ti for KREEP-rich samples (+0.117 to +0.296 ‰) and intra-group variations in the mare basalts (-0.030 to +0.055 ‰ for low-Ti and +0.009 to +0.115 ‰ for high-Ti basalts). We modelled the δ49Ti of KREEP using previously published HFSE data as well as the δ49Ti evolution during fractional crystallisation of the LMO. Both approaches yield δ49TiKREEP similar to measured values and are in excellent agreement with previous studies. The involvement of ilmenite in the petrogenesis of the lunar mare basalts is further evaluated by combining our results with element ratios of HFSE, U and Th, revealing that partial melting in an overturned lunar mantle and fractional crystallisation of ilmenite must be the main processes accounting for mass dependent Ti isotope variations in lunar basalts. Based on our results we can also exclude formation of high-Ti basalts by simple assimilation of ilmenite by ascending melts from the depleted lunar mantle. Rather, our data are in accord with melting of these basalts from a hybrid mantle source formed in the aftermath of gravitational lunar mantle overturn, which is in good agreement with previous Fe isotope data

    3D ground model development for an active landslide in Lias mudrocks using geophysical, remote sensing and geotechnical methods

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    A ground model of an active and complex landslide system in instability prone Lias mudrocks of North Yorkshire, UK is developed through an integrated approach, utilising geophysical, geotechnical and remote sensing investigative methods. Surface geomorphology is mapped and interpreted using immersive 3D visualisation software to interpret airborne light detection and ranging data and aerial photographs. Subsurface structure is determined by core logging and 3D electrical resistivity tomography (ERT), which is deployed at two scales of resolution to provide a means of volumetrically characterising the subsurface expression of both site scale (tens of metres) geological structure, and finer (metre to sub-metre) scale earth-flow related structures. Petrophysical analysis of the borehole core samples is used to develop relationships between the electrical and physical formation properties, to aid calibration and interpretation of 3D ERT images. Results of the landslide investigation reveal that an integrated approach centred on volumetric geophysical imaging successfully achieves a detailed understanding of structure and lithology of a complex landslide system, which cannot be achieved through the use of remotely sensed data or discrete intrusive sampling alone

    Duration and Magnitude of Postoperative Risk of Venous Thromboembolism after Cholecystectomy: A Population-Based Cohort Study

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    Background: This study aimed to identify burden and risk of VTE associated with cholecystectomy in England. Methods: An historical cohort study of cholecystectomy patients from 2001-2011 was undertaken using linked primary (Clinical Practice Research Datalink) and secondary (Hospital Episode Statistics) care data. Crude rates and adjusted hazard ratios (HRs) were calculated for risk of VTE following cholecystectomy using Cox regression.Results: 24 677 patients were identified with a rate of VTE in the first year following cholecystectomy of 2.80 per 1000 person years (95% CI 2.18-3.59). Patients aged >/=70 vs aged 30 vs BMI less than 0 had 2.4-fold increase in risk (HR 2.42, 95% CI 1.40–4.18); open vs. laparoscopic operation had 3-fold increase in risk (HR 2.94, 95% CI 1.55–5.55). Compared to general population, VTE risk was the highest in the first 30 days post-operatively with 9.9-fold risk following emergency cholecystectomy and 4.5-fold risk after inpatient cholecystectomy (HR 9.90, 95% CI 4.42–22.21; HR 4.54, 95% CI 2.85–7.21). Conclusions: Cholecystectomy is associated with a low absolute risk of VTE and we have identified high risk groups including the elderly, obese and those having open surgery

    Magnetic phase separation in ordered alloys

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    We present a lattice model to study the equilibrium phase diagram of ordered alloys with one magnetic component that exhibits a low temperature phase separation between paramagnetic and ferromagnetic phases. The model is constructed from the experimental facts observed in Cu3x_{3-x}AlMnx_{x} and it includes coupling between configurational and magnetic degrees of freedom which are appropriated for reproducing the low temperature miscibility gap. The essential ingredient for the occurrence of such a coexistence region is the development of ferromagnetic order induced by the long-range atomic order of the magnetic component. A comparative study of both mean-field and Monte Carlo solutions is presented. Moreover, the model may enable the study of the structure of the ferromagnetic domains embedded in the non-magnetic matrix. This is relevant in relation to phenomena such as magnetoresistance and paramagnetism.Comment: 12 pages, 11 figures, accepted in Phys. Rev.

    Reduction of Couplings in Quantum Field Theories with applications in Finite Theories and the MSSM

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    We apply the method of reduction of couplings in a Finite Unified Theory and in the MSSM. The method consists on searching for renormalization group invariant relations among couplings of a renormalizable theory holding to all orders in perturbation theory. It has a remarkable predictive power since, at the unification scale, it leads to relations between gauge and Yukawa couplings in the dimensionless sectors and relations involving the trilinear terms and the Yukawa couplings, as well as a sum rule among the scalar masses and the unified gaugino mass in the soft breaking sector. In both the MSSM and the FUT model we predict the masses of the top and bottom quarks and the light Higgs in remarkable agreement with the experiment. Furthermore we also predict the masses of the other Higgses, as well as the supersymmetric spectrum, both being in very confortable agreement with the LHC bounds on Higgs and supersymmetric particles.Comment: 18 pages, 4 figures. To appear in the proceedings of LT-10, Varna. Based on invited talks given at: LT-10, Varna; PACT-2013, Madrid; SQS'2013, Dubna; CORFU 2013, Corfu, and in several invited seminar
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