Miracle-dz/UniFAR-FTUs huggingface dataset:
Determining the magnetic field in the core–mantle boundary zone by non-harmonic downward continuation

Summary The length of day and the geomagnetic field are clearly correlated over decadal periods (10–100 yr). Provided the electrical conductivity of the lower mantle is sufficiently high, a considerable part of this correlation can be explained by electromagnetic core–mantle coupling. Investigating the associated core–mantle coupling torque and fluid velocity fields near the core surface, as well as the interpretation of the observed time lag between length of day and geomagnetic field variations requires the calculation of the temporally variable magnetic field near both sides of and on the core–mantle boundary by solving the magnetic induction equation. Such a solution presents a downward field continuation that has a non-harmonic character if the electrical conductivity is accounted for. In this paper the Earth's mantle is assumed to be a two-layer spherical shell, whose inner layer is electrically conductive. We only consider the poloidal part of the magnetic field with boundary values that are conventionally given by a spherical harmonic expansion of the observed geomagnetic potential field at the Earth's surface. Thus, we are concerned with a one-side-data supported problem, analogous to the inverse heat conduction problem (or sideways heat equation problem), well-known as an ill-posed inverse boundary value problem for a parabolic partial differential equation (diffusion equation). We develop a several-step solution procedure for this inverse problem in its integral form and use a special regularization method for the final solution. The capabilities of this downward continuation method (which includes varying the mantle conductivity model, quality of data approximation in the regularization and two different depths) are presented and discussed in comparison with the perturbation approach and the usual harmonic downward continuation. The data series used are the single magnetic field components (Gauss coefficients) of the spherical harmonic field expansion (Bloxham & Jackson 1992, J. geophys. Res., 97, 19 537–19 563) beginning from the year 1840 to 1990. In addition, to investigate the spectral effects (changing amplitudes, phase shifting), an artificial data series is used. The main result is the downward continuation of the radial component of a global (8,8) field onto the core–mantle boundary, produced using the different methods and for the two epochs, 1910 and 1960. Comparing the results with the perturbation solution reveals temporally and locally variable differences up to the order of 5000 nT, while the difference to the harmonic downward continuation amounts to 15000 nT.
Extension of split perfectly matched absorbing layer for 2D wave propagation in porous transversely isotropic media

The perfectly matched layer (PML) has proven to be efficient in absorbing outgoing waves in elastic and poroelastic media. It has not, however, been applied for porous anisotropic media. We develop the velocity–stress formulation for propagation of seismic waves for fluid-saturated porous anisotropic media with Biot’s equations. Then we extend the split perfectly matched absorbing layer (SPML) to these media and describe the staggered-grid finite-difference scheme. Using fourth-order spatial operators and a second-order temporal operator under 2D Cartesian coordinates, we numerically solve the equations for the solid and fluid particle velocity components, and for the solid stress components and fluid pressure. The energy decay curve we show demonstrates that the algorithm can run stably. Results from the horizontally layered model show that the SPML model absorbs the outgoing wave well, which illustrates the algorithm is efficient for modelling in porous transversely isotropic media.
Cambrothyra ampulliformis, An Unusual Coeloscleritophoran from the Lower Cambrian of Shaanxi Province, China

Abstract Cambrothyra ampulliformis Qian and Zhang, 1983, is a jar- or vase-shaped fossil known from the Lower Cambrian of Shaanxi and Hubei provinces, China. It has been interpreted as a protistan test or cyst or a metazoan sclerite. A large collection of specimens from the Xihaoping Member of the Dengying Formation in southern Shaanxi Province permits its detailed redescription. These fossils are highly variable in shape but this variation is continuous and does not support the current recognition of multiple species for this material. They were originally hollow with a restricted basal foramen and a calcareous wall probably composed of fibrous aragonite. All of these features support the identification of Cambrothyra as sclerites of a coeloscleritophoran, a problematic group of Cambrian scleritome-bearing metazoans. Furthermore, the walls of Cambrothyra sclerites contain numerous pores, a feature shared with other coeloscleritophorans. Cambrothyra resembles chancelloriids in particular due to the shared presence of a verruculose texture around the foramen and the absence of mirror-image pairs of asymmetric sclerites. However, unlike chancelloriids, which have rosette-like compound sclerites, the scleritome of Cambrothyra was dominated by isolated sclerites, with only a few pairs and clusters of sclerites and twin sclerites. Consequently, we hypothesize that Cambrothyra forms a clade with other chancelloriids, but represents a basal lineage that plesiomorphically retained isolated sclerites. The morphology of Cambrothyra sclerites, which shares features with both chancelloriids and halkieriids, thus supports the hypothesis that all coeloscleritophorans form a natural group.
Petrological constraints on the eclogite- and blueschistfacies metamorphism and P-T-t paths in the Western Alps

Phase relationships in the model mafic system and geothermobarometry allow discrimination of four main groups of high-P rocks in the nappes of the Western Alps: very high-P eclogite-facies (including kyanite eclogites and coesite-pyrope assemblages), eclogite-facies (paragonite-zoisite eclogites), high-T blueschist-facies (glaucophane-garnet ± lawsonite assemblages) and low-T blueschist-facies (glaucophane-lawsonite ± pumpellyite assemblages). The blueschist-facies-eclogite-facies transition is promoted chiefly by increasing T, low bulk XMg and relatively low μH2O. The variety of assemblages and the heterogeneous approach to equilibrium observed in the Alpine rocks are not only constrained by the intersection of the reaction surfaces in P-T-X space, but also by the effect and timing of the processes which control kinetics (i.e. pervasive deformation and fluid infiltration). The faster rate of dehydration reactions relative to hydration reactions along with the fact that different bulk compositions crossed the reaction curves at different temperatures (and times), all may have induced μH2O gradients and contributed to the heterogeneous distribution of deformation through a process of reaction-enhanced ductility. Also mass-transfer may have been an effective process in determining the type of high-P assemblage in particular rock volumes. As regards the P-T-t paths, only the post-climax histories are recorded well in the Alpine nappes. Post-eclogitic exhumation paths at decreasing temperatures characterize structurally higher nappes which were first subducted during the early-Alpine (Cretaceous) event. In contrast, more or less isothermal decompression paths characterize structurally deeper nappes formed by westward propagation of the underthrust surfaces during the early-Alpine event and the subsequent meso-Alpine (Palaeogene) collision between the ‘European’and ‘African’plates. In the Western Alps, prevalent eclogite-facies conditions were attained during the metamorphic climax of the early-Alpine subduction, while blueschist-facies recrystallization characterizes the early-Alpine exhumation of the eclogitized units and the subsequent intracontinental underthrusts linked to the meso-Alpine continental collision.
Carbon Isotope Evidence for Ordovician Marine Hydrocarbon Source Rocks in Ordos Basin, North China

Ordos Basin is the second largest sedimentary basin in China with gigantically thick Paleozoic marine sedimentary strata. Geochemical analyses show that the carbon isotope compositions of the Ordovician are less influenced by post-depositional diagenesis and basically accordant with that of the global Ordovician. δ13C values range from – 7.30‰ to 2.26‰ with a mean value of −0.30‰. Temporally, δ13C values are gradually increased from the Early to Late Ordovician with a significant positive excursion between the Middle and Late Ordovician, indicated by increase of the mean value from —0.36 ‰ in the Majiagou Formation to 0.15 ‰ in the Pingliang Formation and up to 0.68 ‰ in the Beiguoshan Formation. There is a good relationship between carbon isotopes and organic carbon contents in the Ordos Basin. The positive carbon isotope excursion indicates higher productivity and organic carbon burial, which can consider as a geochemical index for generation of hydrocarbon source rocks. Based on analysis of carbon isotope and sedimentary environment, it is suggested that the central-eastern part of Ordos Basin is unlikely to form a large-scale efficient hydrocarbon source rocks. The Upper Ordovician Pingliang Formation, Wulalike Formation and Beiguoshan Formation in the southwestern margin are the most important and efficient hydrocarbon source rocks in the Lower Paleozoic in the Ordos Basin. In addition, the Middle Ordovician Kelimoli Formation in the western margin is another important source rocks, and the Fengfeng Formation in the southern margin also has a certain account of hydrocarbon generation potential. Viewing from the development of source-reservoir-cap assemblage, the southwestern margin of Ordos Basin has great exploration potential. Dingbian – Etuokeqi area and Linyou – Tongchuan area, located on the west and south side of Central Paleouplift, respectively, is favorable areas for gas exploration in the Lower Paleozoic in the Ordos Basin.
Multinational Companies, Technology Spillovers and Plant Survival

How does the presence of multinational companies affect plant survival in the host country? We postulate that multinational companies can impact positively on plant survival through technology spillovers. We examine the nature of the effect of multinationals using a Cox proportional hazard model, which we estimate using plant-level data for Irish manufacturing industries. Our results show that the presence of multinationals has a life-enhancing effect only on indigenous plants in high-tech industries, suggesting the presence of technology spillovers. In contrast, multinationals compete with each other in low-tech sectors in the host country.
Magmatic sedimentation and carbonatitic differentiation in kimberlite sills at Benfontein, South Africa

At Benfontein, near Kimberley, South Africa, three sills of kimberlite intrude Dwyka shales and overlying Karroo dolerite. Each sill results from numerous injections of kimberlite that have consolidated to give the sill a layered appearance. Many layers show magmatic sedimentation features and cumulus textures, and, although some show in situ differentiation, other layers result from pre-injection differentiation. The transporting, intercumulus liquid was carbonate-rich and some layers have differentiated to form a carbonate rock composed of the intercumulns calcite; this, on trace element and isotopic data, shows strong affinities with carbonatite. In one of the sills one calcite layer has migrated diapirically into overlying layers in the sill. These sedimentation features, combined with thermal metamorphism of country-rock shales and the presence of quench calcite and apatite, are interpreted as evidence that the kimberlite was injected as a highly mobile fluid, comprising megacrysts of olivine, garnet, pyroxene, mica and picroilmenite in a hot carbonatitic liquid from which olivine, magnetic spinel, perovskite, apatite, calcite, dolomite, ankerite and quartz crystallised. The evidence that the transportation medium was a warm carbonatitic liquid is directly opposed to earlier hypotheses proposing that kimberlite is intruded as a cold or plastic paste, and also supports proposals of a genetic link between kimberlite and carbonatite.
Review: Testosterone and the metabolic syndrome

Metabolic syndrome and testosterone deficiency in men are closely linked. Epidemiological studies have shown that low testosterone levels are associated with obesity, insulin resistance and an adverse lipid profile in men. Conversely in men with metabolic syndrome and type 2 diabetes have a high prevalence of hypogonadism. Metabolic syndrome and low testosterone status are both independently associated with increased all-cause and cardiovascular mortality. Observational and experimental data suggest that physiological replacement of testosterone produces improvement in insulin resistance, obesity, dyslipidaemia and sexual dysfunction along with improved quality of life. However, there are no long-term interventional studies to assess the effect of testosterone replacement on mortality in men with low testosterone levels. This article reviews the observational and interventional clinical data in relation to testosterone and metabolic syndrome.
Proposition For The Application Of AGrid-connected Photovoltaic (PV) System:Koya City As A Study Case

Renewable energy is energy that is derived from natural processes that are replenished constantly. Unlike fossil fuel, renewable energy does not pollute the environment because it is a part of nature. Renewable sources that are most often used are solar, wind, water (hydropower), biomass and geothermal energy. The potential to generate energy from renewable sources is largely dependent on the availability of these natural resources. Among the renewable energy resources, the energy through the photovoltaic (PV) – which converts the sunlight directly into electricity – can be considered the most essential and prerequisite sustainable resource. The standalone PV system cannot provide a continuous supply of energy due to seasonal and periodic variations. Therefore, in order to satisfy the load demand, grid-connected energy systems are now being implemented that combine the PV system with the grid system. The gridconnected PV system can be divided into two parts: building integrated PV systems (BIPV) and distribution generation PV (DGPV) systems. BIPV systems usually supply a specific load and inject the excess energy to the grid while DGPV systems directly inject the energy to the grid. The suggestion in this paper is that the BIPV system is applied for some special building in a Koya city like: the university’s new presidency building, Shaid-Khalid new hospital and the new bank buildings. This application will be the first step of going toward renewable energy usage with the grid system in Kurdistan region.
Lightning flashes from a prescribed fire‐induced cloud

A prescribed fire was ignited near Chapleau, western Ontario, Canada, on the afternoon of August 10, 1989. The fire, covering approximately 400 ha, burned vigorously over a period of 3 hours, from 1400 to 1700 EDT, generating a plume cloud structure including a portion resembling an anvil. During the period 1500–1630, 21 ground flashes lowering positive charge from the plume cloud were observed simultaneously by an electric field mill near the fire and a lightning location system. Four negative flashes that occurred at the beginning of the time period were not recognized as ground flashes by the location system. These four flashes out of a total of 37 flashes exceeding 90 V/m at the electric field meter were the only flashes perceived as lowering negative charge; all the others lowered positive Charge, whether recognized by the locating system as ground flashes or not. The median current of the positive flashes to ground as calculated from the location system output was 36 KA. Application of simple models of charge distribution to the plume structure indicate that the plume and associated cloud had a monopolar charge distribution, with positive charge at altitude and that the fire was most probably the source of this charge. A charge generation rate of 2 nC/m2/s by the fire could generate enough charge to satisfy the flash discharge rate and amount using the simplest model. The locations for the ground termini of the flashes are downwind of the fire location, some by as much as 30 km. They seem to be associated with the anvillike structure of the plume, although it is known that positive ground flashes commonly occur at considerable horizontal distances from their origin. There is no time organization to the distances of the termini from the fire.
Microplate and shear zone models for oceanic spreading center reorganizations

The reorganization of oceanic spreading centers is often accomplished through the process of rift propagation. We first examine general rift propagation geometries for the simple two-plate case in which the propagating rift instantaneously reaches full spreading rate while the other rift dies instantaneously, such that the propagating and dying rifts never overlap. A velocity space representation provides a framework for describing the geometry of rift propagation and its various tectonic elements, and shows how both the failed rift and isochrons between the two rifts are reoriented as a consequence of purely rigid plate tectonics. We then discuss the more complex geometries that result when both growing and dying rifts spread simultaneously during propagation, such that a technically independent overlap region, like the Easter or Juan Fernandez plates along the East Pacific Rise, is produced. We examine the effect of the propagation rate and rise time of spreading on the evolution of overlap regions between dual oceanic spreading centers. The tectonics and evolution of such regions can be modeled by assuming that they act either as rigid microplates or as zones of distributed shear. Rigid plate models are suggested by the reasonable success of Euler vectors derived from inversions of plate motion data (spreading rates, transform azimuths, and slip vectors) both in describing available data and in predicting subsequently acquired data. On the other hand, recent structural data showing fabric oblique to the surrounding spreading centers might suggest shearing, rather than rigid behavior, in the interior of the Easter microplate. We use schematic evolutionary simulations for an Easter-style geometry to examine whether plate motion data and orientations of preexisting and present structures can be used to discriminate between rigid and shear models. In a microplate model, rigid plate tectonics requires that relative motion occur only along the boundaries of the overlap region, while structures within the overlap zone rotate rigidly. In contrast, in a shear model, relative motions at the boundaries differ from those predicted by rigid plate tectonics, and the angular relationships of structures within the overlap region are altered by internal deformation. Thus inversion of relative motion data yields different results for rigid and shear behavior. Similarly, under favorable circumstances, structural trends could be diagnostic of the different cases. We find that much of the Easter structural data suggestive of shearing are also consistent with rigid plate tectonics. We conclude that microplate models offer useful testable hypotheses for describing overlap systems and that shearing need be invoked only to explain features not describable by rigid plate tectonics. Furthermore, the approaches used here to study current overlap regions should be useful in the analysis of similar regions formed during past oceanic plate boundary reorganizations.
The Significance of Hummocky Cross-Stratification (HCS) Wavelengths: Evidence from an Open-Coast Tidal Flat, South Korea

Abstract Although hummocky cross-stratification (HCS) is one of the most common and widely recognized structures in ancient storm-dominated successions, the stratigraphic variability and environmental significance of HCS wavelength (λ) are still not widely appreciated. New evidence from an open-coast intertidal flat where HCS might not have been expected to occur shows that the HCS becomes smaller in a landward direction because of a decrease of wave size. This confirms previous suggestions that the bedform responsible for HCS is a type of orbital ripple. A review of new and previously published data indicate that HCS wavelength is controlled by the bottom orbital diameter (d0) according to the relationship λ 0.75 d0. These observations imply that the maximum size of HCS should increase with decreasing water depth from the shelf to the surf zone (breaking point) but may then decrease landward of this point because wave size is depth limited. This suggests that it may be possible to use HCS size in paleo-environmental reconstructions to a greater degree than previously.
Effect of soil moisture and vegetation heterogeneity on a Great Plains dryline : a numerical study, The

Abstract : The impact of heterogeneous soil moisture and vegetation fields on a Great Plains dryline are examined through the use of a mesoscale numerical model. A three dimensional, non-hydrostatic, nested grid version of the Colorado State University Regional Atmospheric Modeling System (RAMS) was used to perform five simulations of an actual dryline which was observed as part of the COPS-91 field experiment on 15 May 1991. A control run which was designed to reproduce the observed conditions as accurately as possible was generated and verified against standard National Weather Service observations, PAM-II observations, M-CLASS soundings, and vertical cross section analyses obtained from the NOAA P-3 aircraft. A representative heterogeneous soil moisture field for use in the control simulation was generated using an antecedent precipitation index (API). Variable vegetation was input using the Biosphere-Atmosphere Transfer Scheme (BATS) and included 18 categories of land surface type derived from the USGS NDVI dataset. Because the standard RAMS code modifies the surface fluxes by the Leaf Area Index (LAI), the LAI was limited to a value of 3.0 or less in the flux calculations for all vegetation types although the BATS scheme assigns values of LAI as high as 6.0. Justification for this limitation is presented.
The response of braided planform configuration to flow variations, bed reworking and vegetation: the case of the Tagliamento River, Italy

Morphological features of braided rivers (bars, channels and pools) experience major changes in area, shape and spatial distribution as a response to (i) the pulsation of discharge during a flood and (ii) the bed evolution induced by floods. In this work, at‐a‐station relationships between water level and planform configuration were investigated on the Tagliamento River, a large gravel‐bed braided river in northeast Italy, over a 2‐year study period comprising three bankfull events and several small‐to‐medium floods. The analysis was performed on two 1‐km‐long reaches, characterized by different riparian vegetation cover. Ground‐based images with an hourly temporal resolution were acquired using software‐controlled, digital cameras. Bars, channels, pools and vegetated patches were manually digitized on more than 100 rectified images. Sequences of constant‐level images spanning the study period were used to quantify the impact of floods on the stability of at‐a‐station relationships and on the turnover rate of water bodies.