Miracle-dz/UniFAR-FTUs huggingface dataset:
Remagnetization in bituminous limestones of the Neoproterozoic Araras Group (Amazon craton): Hydrocarbon maturation, burial diagenesis, or both?

[1] Neoproterozoic carbonates of the Araras Group exhibit two distinct magnetic components across the same carbonate succession in a cross-section between the Amazon craton and the Paraguay fold belt. Pink dolostones of the Mirassol d'Oeste Formation carry a dual polarity, primary component, whereas black bituminous limestones of the Guia Formation yield a secondary postfolding component. Magnetic signatures of the Guia limestones, such as high anhysteretic remanence magnetization/saturation isothermal remanence magnetization ratios, high-frequency-dependent magnetic susceptibility and contradictory Lowrie-Fuller and Cisowski tests, are typical of remagnetized carbonates. Unblocking temperatures suggest that the stable high-temperature remanence is carried by both pyrrhotite and magnetite for which an authigenic origin is suggested by scanning electron microscope observations. The different magnetic properties noted between dolostones with or without bitumen and between dolostones and limestones in the same metamorphic conditions lead to the hypothesis that the amount of hydrocarbon as well as the lithology influence nucleation of authigenic magnetic minerals in these rocks. Presence of magnetite pseudoframboids and euhedral iron sulphide crystals occurring in fracture and voids are in favor of a chemical remanence (CRM). The presence of pyrrhotite as one of the main carriers of CRM in these rocks, and its association with bitumen in fractures is probably related to an epigenetic enrichment of sulfur due to hydrocarbon seepage. However, hydrocarbon maturation solely could not explain the differences of the magnetic mineralogy observed in the craton and the fold belt. Enhanced magnetite formation in the thrust and fold belt is interpreted to be the result of higher temperatures leading to stronger diagenesis of clay minerals.
Anisotropy of G0 shear stiffness in Gault Clay

The inclusion of anisotropic stiffness parameters in sophisticated constitutive models necessitates their determination in the field and laboratory. Hitherto, anisotropy of small-strain stiffness of clays has occasionally been examined in the laboratory by measurements on specimens sampled at different orientations. The authors have developed a device to propagate and receive horizontal shear waves with both vertical and horizontal polarization through 100 mm triaxial samples. The device incorporates bender elements embedded in the pads of a horizontal belt. In tests on both reconstituted and natural samples of Gault Clay, each of the transmission velocities Vs(xh), Vs(hx) and Fs(hh) has been measured during stress path tests. The ratio G0(hh)/G0(vh) has been shown to be highly dependent on stress state. Laboratory data on natural samples show results broadly consistent with in situ results. Pour pouvoir inclure des parametres de rigidite anisotrope dans des modeles constitutifs perfectionnes, il faut les.
Ice nucleation by surrogates for atmospheric mineral dust and mineral dust / sulfate particles at cirrus temperatures

Ice nucleation by surrogates for atmospheric mineral dust and mineral dust/sulfate particles at cirrus temperatures C. M. Archuleta, P. J. DeMott, and S. M. Kreidenweis Department of Atmospheric Science, Colorado State University, Fort Collins, 80523-1371 Colorado, USA Received: 14 April 2005 – Accepted: 2 May 2005 – Published: 30 May 2005 Correspondence to: P. J. DeMott (pdemott@lamar.colostate.edu) © 2005 Author(s). This work is licensed under a Creative Commons License.
Vertical velocities and dynamical balances in Gulf Stream meanders

A triangular array of current meter moorings was deployed within the cyclonic flank of the Gulf Stream in the South Atlantic Bight from September 1981 to April 1982. Using velocity and temperature data and the nondiffusive heat equation, a time series of vertical velocity was derived. A mean vertical velocity of −0.013 cm s−1 and standard deviation of 0.078 cm s−1 were obtained. To better understand the subsurface structure of Gulf Stream meanders, the time series of horizontal and vertical velocities and temperature were examined at times when events were passing through the array. The flow along the trailing edge of a Gulf Stream meander and within the leading portion of a cold core frontal eddy was found to have an upward component (positive w), while that within the trailing portion of the frontal eddy and along the leading edge of a meander had a downward component (negative w). Using the horizontal and vertical velocity time series, cross-stream and along stream momentum balances were calculated. The downstream flow was found to be in geostrophic balance. In contrast, the Coriolis and nonlinear terms were found to contribute equally to the determination of the cross-stream flow.
Regions of Risk: A Geographical Introduction to Disasters

* APPROACHES TO RISK AND DISASTER: Introduction: Danger and ModernityRisk and Damaging Events * The Geographicalness of Disaster * Natural Hazards * Technological Hazards * Social Hazards: Violence and the Disasters of War * Vulnerability Perspectives: The Human Ecology of Endangerment * Active Perspectives: Responses to Disaster and Adjustments to Risks * COMMUNITIES AT RISK, PLACES OF DISASTER: 'Unnatural' Disasters: The Case of Earthquake Hazards * Contexts of Risk: Mountain Land Hazards and Vulnerabilities * Risks in the City * Place Annihilation: Air War and the Vulnerability of Cities * Holocaust: Genocide and Geographical Calamity Concluding Remarks: the perspective of ideas
Axial Compression of Footings in Cohesionless Soils. I: Load-Settlement Behavior

The results of 167 full-scale field load tests were used to examine several issues related to the load-displacement behavior of footings in cohesionless soils under axial compression loading, including (1) method to interpret the “failure load” from the load-settlement curves; (2) correlations among interpreted loads and settlements; and (3) generalized load-settlement behavior. The L1 - L2 method was found to be more appropriate than the “tangent intersection” and “10% of the footing width” methods for interpreting the failure load. The interpreted loads and displacements indicate that footing load-settlement behavior is less elastic and more nonlinear than that of drilled foundations. The results show that the footing behavior will be beyond the elastic limit for designs where a traditional factor of safety between 2 and 3 is used. A normalized curve was developed by approximating the load-settlement curve for each load test in the database by hyperbolic fitting, and the uncertainty in this curve was qu.
Magnitude of post–Middle Jurassic (Bajocian) displacement on the central Altyn Tagh fault system, northwest China

The Altyn Tagh fault system, a key structural feature in the tectonic collage of central Asia, is an active left-lateral strike-slip fault system. However, its age of initiation, kinematic history, and total magnitude of displacement are not well known. Middle Jurassic nonmarine sedimentary rocks that crop out along the central segment of the Altyn Tagh fault were deposited in a contiguous Tarim-Qaidam foreland-style basin that was geodynamically linked to Mesozoic contraction in the Tian Shan, Bei Shan, Qilian Shan, and Kunlun Shan. This study documents the best evidence of a piercing point to date, consisting of an offset lacustrine shoreline demarcated by Aalenian-Bajocian open lacustrine strata to the west and fluvial and alluvial strata of comparable age to the east. Detrital compositions, palynology, paleocurrents, and lithostratigraphy support correlation of these sections. Restoration of this Jurassic facies boundary indicates 400 ± 60 km of post-Bajocian left-lateral separation on the Altyn Tagh fault. Consistent with this result, restoration of the Jurassic shoreline aligns felsic plutons across the western segment of the Altyn Tagh fault system that may have been left-laterally offset by 360 km. These two pairs of offset features suggest that the current best estimate for net magnitude of post-Bajocian left-lateral separation on the Altyn Tagh fault is about 360 km.
Stable and scalable congestion control for high-speed heterogeneous networks

For any congestion control mechanisms, the most fundamental design objectives are stability and scalability. However, achieving both properties are very challenging in such a heterogeneous environment as the Internet. From the end-users' perspective, heterogeneity is due to the fact that different flows have different routing paths and therefore different communication delays, which can significantly affect stability of the entire system. In this work, we successfully address this problem by first proving a sufficient and necessary condition for a system to be stable under arbitrary delay. Utilizing this result, we design a series of practical congestion control protocols (MKC and JetMax) that achieve stability regardless of delay as well as many additional appealing properties. From the routers' perspective, the system is heterogeneous because the incoming traffic is a mixture of short- and long-lived, TCP and non-TCP flows. This imposes a severe challenge on traditional buffer sizing mechanisms, which are derived using the simplistic model of a single or multiple synchronized long-lived TCP flows. To overcome this problem, we take a control-theoretic approach and design a new intelligent buffer sizing scheme called Adaptive Buffer Sizing (ABS), which based on the current incoming traffic, dynamically sets the optimal buffer size under the target performance constraints. Our extensive simulation results demonstrate that ABS exhibits quick responses to changes of traffic load, scalability to a large number of incoming flows, and robustness to generic Internet traffic.
A thermal instability for the spread‐F echoes from HF‐heated ionosphere

A thermal instability is studied for the generation of large-scale field-aligned irregularities in the F-region of the ionosphere. These irregularities are then explained to be the cause of the spread-F traces in the ionograms recorded in the recent Arecibo heating experiments. The background plasma is assumed to have an elevated electron temperature and a localized heat source located near the HF reflection height. The elevated electron temperature is maintained by the heat source which is supplied by the HF heater. The dispersion relation of the instability is derived and analyzed for the threshold condition and the growth rate. The calculated growth time of the large-scale irregularities is consistent with the Arecibo observations when measured electron-to-ion temperature ratios in the range between 2 and 3 are used in the analysis.
Observed volume fluxes in the Bosphorus Strait

Pairs of moorings containing acoustic Doppler current profilers (ADCPs) were deployed at each end of the Bosphorus Strait as a part of the United States Naval Research Laboratory's “Exchange Processes in Ocean Straits (EPOS)” project. The moorings were deployed in September 2008 and remained in place for about half a year. For the first time, current velocity profiles were collected concurrently at both ends of the strait. They well resolved the two‐layer exchange flow and were used to estimate volume flux time series. These estimates clearly indicated that there was a mean net volume flux of over 100 km3/yr directed from the Black Sea to the Sea of Marmara over this period. The upper‐layer fluxes showed distinct temporal variability whereas the lower‐layer fluxes varied less. Volume fluxes were maximized at over 1500 km3/yr in the upper layer and over 1100 km3/yr in the lower layer, with an upper‐layer mean of about 400 km3/yr and a lower‐layer mean of about 300 km3/yr. Fluxes in both layers were highly coherent with the bottom pressure difference between the southern and northern ends of Bosphorus Strait, and they can be fairly well predicted from this pressure difference. The fluxes in the upper layer were also influenced by atmospheric forcing, but generally less so than by the bottom pressure difference.
A new method for moving–boundary hydrodynamic problems in shallow water

Dynamic moving–boundary problems are a common occurrence in shallow–water hydraulics, yet no generally applicable or computationally efficient framework is available for their solution. In this paper a new scheme is presented that attempts to solve the problem of representing moving–boundary shallow–water hydrodynamics on fixed numerical grids. The scheme consists of three parts: identification of partly wet elements; the development of physically appropriate treatments to deal with mass and momentum conservation discrepancies in such areas within a two–dimensional finite–element framework; and the development and testing of a proof of mass conservation for the new scheme. In particular, the algorithm is unique in distinguishing between flooding and dam–break partly wet elements in contrast to previous solutions to this problem which typically treat both types in a similar fashion. In reality, consideration of the problem physics shows that mass and momentum conservation discrepancies can only be positively identified and corrected on elements of the flooding type. Accordingly, this disaggregation of partly wet elements into flooding and dam–break types is the approach adopted. This new scheme is tested against a structured series of numerical experiments including objective tests, a newly developed analytical solution for this problem and a unique high–resolution topographic data–set recently collected for an area of tidal beach on the eastern coast of the UK. The new scheme is shown to be physically realistic, mass conservative and appears to offer a significant improvement over standard finite–element techniques.
Variance in trace constituents following the final stratospheric warming

Temporal variances in the concentration of trace species are examined within the northern hemisphere stratosphere following the final warming. Variances are computed utilizing an annual cycle run of a tracer transport model and stratospheric balloon observations. The model uses winds generated with a general circulation model to transport N2O. Regions of significant N2O variance are produced immediately following the modeled final warming as zonally inhomogeneous N2O anomalies are created during the warming, then advected passively about the pole by easterly winds. Diffusion rapidly dissipates these anomalies and decreases the associated stratospheric tracer variance to very low levels by June. On monthly timescales the 10 day normal mode explains up to 50% of the modeled variance of N2O during summer. On these timescales potential temperature exhibits less variability than N2O, as horizontal parcel displacements are relatively ineffective at inducing potential temperature variability. An examination of balloon observations of N2O and other long lived trace species, between 40° and 50°N, indicates that the primary component of the tracer variance during June is on an interannual time scale. We attribute this interannual variability to stratospheric variability during the winter and early spring months imprinted onto the distributions of long lived tracers. Potential temperature does not exhibit much interannual variability because it does not retain a memory of the previous winter's circulation.
Modeling the hydrologic responses of the Pampanga River basin, Philippines: A quantitative approach for identifying droughts

Drought in the Philippines has been monitored for agricultural and economic losses, but spatial and temporal characterization at the basin scale has not been quantified. The relationship between different drought types, and how these can be integrated into timely water‐resource‐management planning in the agriculture and water sector of the Pampanga River basin, were considered. Specifically, the objectives of this study are as follows: (1) to propose a standardized anomaly (SA) index for assessing different types of drought impacts at the basin scale; (2) to quantify vulnerability of the agriculture and water sectors using physically consistent hydrological parameters with temporal variation and spatial heterogeneity; (3) to develop a method for combining the drought index calculated from the inputs and outputs of WEB‐DHM on the basis of sturdy algorithms for the physics of water and energy movement in the basin using monthly and seasonal differences of various drought types; and (4) to combine hydrological parameters with crop production to determine its effects on rice. The SA was calculated for the variables related to each drought type: rainfall (meteorological), streamflow and groundwater (hydrological), and soil moisture (agricultural) during 1983, 1987, 1990–1992, and 1998 droughts. El Niño is one of the major driving forces leading to drought in the country. The drought intensified on the second year of the average two‐year El Niño Southern‐Oscillation (ENSO) composites with a 1 to 7 month time lag between parameters and hot spots in the upland and central plains of the basin. Recommended adaptation strategies include crop scheduling, crop/livelihood substitutes, and alternative water sources.
Monetary policy transmission in the euro area

The monetary transmission mechanism consists of the various channels through which monetary policy actions affect the economy and the price level in particular. A good understanding of the transmission mechanism is an important prerequisite for implementing a sound policy, as it allows a judgement to be formed as to the extent and the timing of monetary policy decisions which are appropriate in order to maintain price stability.
Surging glaciers

or manmade cavities in the marginal parts of glaciers (Boulton, 1974; Theakstone, 1979; Anderson et al., 1982), a situation which may not be representative of large areas of the glacier bed. Photographic observations made in boreholes drilled to the glacier bed (Engelhardt et al., 1978) are difficult to extrapolate to wider areas of the interface and may be unrepresentative because basal conditions may be changed by the existence of the borehole. The same may be said of observations made in artificial cavities excavated under the central parts of glaciers (Wold and 0strem, 1979; Vivian, 1980; Hagen, et al., 1983). Important developments in our understanding of subglacial processes have, therefore, come from inference of process from form (Gilbert, 1906; Hallet, 1979a; Walder and Hallet, 1979; Hallet and Anderson, 1981) and from theoretical investigations (Boulton, 1974, 1975; 1979; Hallet, 1979b; 1981), but since it has rarely been possible to test theory against field observation, even the
Scaling characteristics of SEGMA magnetic field data around the Mw 6.3 Aquila earthquake

We apply detrended fluctuation analysis (DFA) on fluxgate and search-coil data in ULF range (scales 10–90 s or 0.1–0.011 Hz) for the months January–April 2009 available from the South European GeoMagnetic Array stations: Castello Tesino (CST), Ranchio (RNC), and L’Aquila (AQU) in Italy; Nagycenk (NCK) in Hungary; and Panagyuriste (PAG) in Bulgaria. DFA is a data processing method that allows for the detection of scaling behaviors in observational time series even in the presence of non-stationarities. The H and Z magnetic field components at night hours (00-03 UT, 01–04 LT) and their variations at the stations CST, AQU, NCK, and PAG have been examined and their scaling characteristics are analyzed depending on geomagnetic and local conditions. As expected, the scaling exponents are found to increase when the Kp index increases, indicating a good correlation with geomagnetic activity. The scaling exponent reveals also local changes (at L’Aquila), which include an increase for the Z (vertical) component, followed by a considerable decrease for the X (horizontal) component in the midst of February 2009. Attempts are made to explain this unique feature with artificial and/or natural sources including the enhanced earthquake activity in the months January–April 2009 at the L’Aquila district.
Ocean dynamics associated with rapid J2 fluctuations: Importance of circumpolar modes and identification of a coherent Arctic mode

[1] Fluctuations of the Earth's dynamic oblateness J2 are a measure of global redistributions of mass between equatorial and polar regions, sensitive to the component which is symmetric about the equator. Cox and Chao recently published a time series of monthly values of J2 based on satellite orbit determination, which showed rapid fluctuations from month to month, as well as a large change in J2 in 1997/1998. We here investigate the ocean dynamics associated with these rapid fluctuations using a barotropic ocean model forced by atmospheric wind stress and pressure. We find that the model has significant skill in reproducing the observations, though not the change in 1997/1998. Much of the model variability is related to coherent circumpolar fluctuations in Arctic and Antarctic bottom pressure which, despite their apparent symmetry, are forced by quite different mechanisms. The Antarctic mode is forced by circumpolar winds, whereas the Arctic mode is forced by northward winds over the entrances to the polar sea. Comparison with in situ observations shows that the model has skill in reproducing the polar modes. Arctic tide gauge records confirm the presence of a coherent mode at short periods, and at long periods over at least the Eurasian Arctic shelf. If barotropic, and representative of the whole Arctic, this would be large enough to make a major contribution to measured J2 fluctuations, but does not account for the 1997/1998 event.