Miracle-dz/UniFAR-FTUs huggingface dataset:
Drying and oxidation effects on the magnetic properties of sulfidic material during oxidation

Laboratory experiments aimed at understanding the changes in magnetic properties of a sulfidic clay during its oxidation are described. Samples of a sulfidic clay from an acid sulfate soil were slowly oxidized and their magnetic susceptibility (χ) and remanence properties (ARM and SIRM) were measured over a 28 week period. Magnetic properties were measured for the undried material and for subsamples which had been dried by rapid air-drying or by extraction of water with dioxane. Magnetic susceptibility decreased during the first 12 weeks of oxidation and then increased. Samples dried in dioxane showed similar values to the undried material, but air drying caused decreases in χ in samples taken up to 7 weeks of oxidation. Thereafter, there was no effect of drying on χ. In contrast to susceptibility, the remanence properties decreased throughout the experiment, to 8% of their initial values. The results were interpreted in terms of rapid chemical oxidation of a labile magnetic compound (possibly greigite) during the early stages of oxidation and by air drying, and the biological oxidation of pyrite during later stages of oxidation. Associated with these reactions was the formation of a paramagnetic compound, probably ferrihydrite. The effects of changes in iron mineralogy during 28 weeks of oxidation on χ are shown schematically.
Acoustic Structure and Seismic Velocities in the Carnarvon Basin, Australian North West Shelf: Towards an Integrated Study

High quality refraction and wide-angle reflection seismic data recorded by ocean-bottom seismographs (OBSs) deployed by the Australian Geological Survey Organisation along the 700 km long transect in the Carnarvon Basin effectively supplement results obtained by means of the conventional reflection technology. Velocity information can now be derived from both CDP (nearvertical reflection) and OBS (refraction/wide-angle reflection) data. Generally, CDP-derived average velocities are lower than OBS-derived velocities and this deviation increases with depth: from ~0.1 km/s at 8 s two way time (TWT) to 0.8-1.6 km/s at 16 s TWT. If the CDP-derived velocities are used to depth convert reflection data, then depth to these TWTs would be underestimated by 0.4 to 6.4-12.8 km respectively. Some local anomalies (at ~6s TWT CDP-derived velocities may be more than 0.1 km/s higher than the OBS-derived velocities) distort this general trend. These would result in ~0.3 km local overestimates of the depth equivalent of 6s TWT. Co-analysis of the interval velocity field reconstructed from the travel time-based interpretation of the OBS data and the conventional reflection image of the crust in some cases shows their poor correlation. Prominent reflectivity seen in the conventional reflection data at depth 13-17 km does not correspond to any significant velocity increase imaged by refraction/wide-angle techniques. These reflections were taken in our pre-OBS interpretation to mark the top of the underplated layer in the crust. Velocity below that level estimated from the OBS data is in the range 5.7-6.4 km/s. This velocity range is considerably lower than anticipated for mafic rocks under appropriate PTconditions. Quite significant local velocity increase in the depth range 15-23 km does not produce high-amplitude near-vertical reflections. Only a combination of reflection and refraction/wideangle techniques provides a clue to a consistent geological interpretation of seismic data. Improved velocity estimation in the crust is crucial for accurate depth conversion of near-vertical reflection data.
Margin architecture reveals the transition to the modern Antarctic ice sheet ca. 3 Ma

Seismic reflection data collected primarily on the continental slope of the Pacific margin of the Antarctic Peninsula after drilling Ocean Drilling Program (ODP) Leg 178 allow us to date a regional change in the style of margin accretion to ca. 3 Ma. Late Pliocene deep erosion of continental shelf and slope, which likely included the emplacement of a megadebris-flow deposit, was followed by prominent growth of steep, relatively stable continental slope prograding wedges, while the deep distal margin sedimentation rate was significantly reduced. A review of the available stratigraphy from Deep Sea Drilling Project–ODP drilling, and correlation with available seismic stratigraphic information, allowed us to recognize comparable changes in terms of age and trends in continental margin evolution in several places around Antarctica. We argue that this late Pliocene architectural change of the Antarctic margin reflects a change in the texture and water content of the sediment delivered by the Antarctic ice sheet following the transition from wet- to dry-based ice regimes. This circum-Antarctic change coincides with the late Pliocene (ca. 3 Ma) global cooling and is proposed as the marker event of the transition to the modern cold polar dry-based Antarctic ice sheet.
Geological indexes of hydrothermal venting

Hydrothermal venting occurs on mid-ocean ridge axes with a diverse array of morphological, structural, and petrological characteristics. Consequently, it is not clear if certain geological environments are more conducive than others to hydrothermal activity. This paper uses complementary data sets recently collected on multiple-tectonic-segment scales along intermediate to superfast spreading ridge sections to systematically examine this issue. The spatial density of venting is gauged by plume incidence, the fraction of linear ridge crest overlain by hydrothermal plumes. Five geological indexes are compared with plume incidence: ridge-axis elevation, ridge-axis cross-sectional area, the percentage of ridge axis underlain by an axial magma chamber (AMC) reflector, MgO wt% in basaltic glass, and spreading rate. A mean value for plume incidence and each index, where available, is calculated for each of 14 second- to fourth-order tectonic segments from the Juan de Fuca Ridge (44°30′ to 48°45′N) and the northern (9° to 11°50′N) and southern (13°50′ to 18°40′S) East Pacific Rise. Plumes are most common on segments with a cross-sectional area >3.5 km2, a net elevation >0.35 km, AMC coverage >60%, and MgO >7 wt%. Spreading rate is not deterministic on the segment scale. The data suggest two classes of ridge segments. Segments with relatively low geological index values have a uniformly low plume incidence indicative of a presently feeble magmatic budget. Those with high index values have a plume incidence ranging from low to complete coverage, apparently a consequence of a magma supply rate sufficient to produce frequent dike intrusions and highly variable hydrothermal activity. The best individual predictors of hydrothermal activity are cross-sectional area and net elevation. Applying these indexes to the East Pacific Rise between 18°N and 33°S suggests that the unexplored segments with the highest probability of activity are those at 15°30′–16°N, 6°–9°N, 5°–6°S, 27°–28°S, and 30°30′–33°S.
Zonal harmonic standing waves

The first three zonal harmonic waves in the troposphere and lower half of the stratosphere in January are described by long-term monthly means and by monthly means for 7 single years. The temperature waves are included in the monthly means for 7 years. Unlike those in the northern hemisphere the standing pressure waves in the troposphere at middle southern latitudes are nearly in phase with the temperature waves and therefore slope little from the vertical or not at all. This situation is possible only over an ocean that is continuous around the earth.
Carbon Monoxide Intoxication

From Department of Emergency Medicine, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan Address for reprints: Dr. Tzong-Luen Wang, Department of Emergency Medicine, Shin-Kong Wu Ho-Su Memorial Hospital, No 95, Wen Chang Road, Taipei, Taiwan Received: Aug 18 2005. Revised: Aug 23 2005. Accepted: Aug 29 2005. TEL: 886-2-28389425 FAX: 886-2-28353547 E-mail: M002183@ms.skh. org.tw Abstract There is sufficient evidence to suggest that significant numbers of our population are being poisoned by low concentrations of carbon monoxide (CO). In otherwise healthy people, occult indoor exposure may result in commonplace symptoms such as headache, dizziness, weakness, and difficulty in concentrating. In people with pre-existing disease, pollution alone may result in increased morbidity and mortality. Variable symptoms and signs make the poisoning difficult to detect and lead to serious outcomes. Multiple laboratory and image study can help us to detect and diagnose CO poisoning. Although the use of hyperbaric oxygen (HBO) therapy is still controversial after many well-designed studies, many authors recommend the HBO in specific group. The other treatments, such as glucagon or steroid warrant further investigation. ED physicians have to learn to early detect the poisoning and to lower the morbidities and mortalities by appropriate management. (Ann Disaster Med. 2005; 4 Suppl 1:S8-S17)
Restudy of Permo-Carboniferous synapsid Edaphosaurus novomexicanus Williston and Case, the oldest known herbivorous amniote

Reexamination of the holotype and the description of new material of Edaphosaurus novomexicanus from the PermoPennsylvanian Cutler Formation of north-central New Mexico reveals that this species is the most primitive member of the Edaphosaurus clade. This assignment, based previously upon supposed plesiomorphies of the postcrania, is supported here by two primitive character states that occur in a derived form in the Texan species of Edaphosaurus. The presence of two autapomorphies in E. novomexicanus suggests that this species is probably not a morphological relict, as previously supposed, but may be part of a lineage that did not exhibit the level of diversification seen in its probable sister group, the clade of Texan edaphosaurids (E. boanerges, E. cruciger, and E. pogonias).
Monitoring of Atmospheric Aerosol Parameters with the Integrating Nephelometer

The integrating nephelometer of Beuttel and Brewer has been adapted successfully for continuous, objective monitoring of atmospheric aerosols. The paper includes a summary of work done to date with this improved device. In particular, the following points are discussed: (1) the design and operation of the instrument; (2) calibration of the instrument; (3) correlation of nephelometer output to the mass concentration of atmospheric aerosol; (4) correlation of nephelometer output with visual range; (5) the wavelength dependent nephelometer and the regularity of the wavelength dependence of haze; and (6) application of integrating nephelometer to mobile reconnaissance of aerosols. The utility of the integrating nephelometer for monitoring visibility and aerosol mass concentration is also emphasized.
Sedimentary History of Mangrove Cays in Turneffe Islands, Belize: Evidence for Sudden Environmental Reversals

ABSTRACT McCloskey, T.A. and Liu, K. -B. , 2013. Sedimentary history of mangrove cays in Turneffe Islands, Belize: evidence for sudden environmental reversals. The Holocene history of the continental margin of Belize has frequently been interpreted as being very straightforward, controlled almost entirely by postglacial sea level rise. Depending upon location, the dominant depositional environment, whether coral or mangrove, is either able to keep up with the rising sea level and thereby maintain its integrity through the present, or becomes drowned. Here we present sedimentary evidence from four mangrove cays situated on Turneffe Islands that shows an unusual pattern wherein early mangrove development is replaced by carbonate sedimentation before reverting back to mangroves in the relatively recent past. The bracketed carbonate layers, up to >2 m thick and resembling lagoon-floor material, display both a rough temporal coincidence across sites and a distinctive geographic signature, thinning landward irrespective of relative elevation. The carbonate sections are often underlain by a mixed sediment layer characterized by a jumble of stratigraphically incoherent mangrove clumps intermingled with carbonates. The replacement of mangrove peat with bottom-style carbonate deposition suggests a lowering of island surface elevation. Seismic activity is identified as the most likely cause, although hurricanes cannot be excluded. In either case the elevational reduction is probably amplified by peat collapse associated with mangrove mortality. The occurrence of such activity and the resulting catastrophic ecological/geomorphic change indicate a need for incorporating these geological perturbations in risk assessment for Turneffe Islands.
The PDM rainfall-runoff model

The Probability Distributed Model, or PDM, has evolved as a toolkit of model functions that together constitute a lumped rainfall-runoff model capable of representing a variety of catchment-scale hydrological behaviours. Runoff production is represented as a saturation excess runoff process controlled by the absorption capacity (of the canopy, surface and soil) whose variability within the catchment is characterised by a probability density function of chosen form. Soil drainage to groundwater is controlled by the water content in excess of a tension threshold, optionally inhibited by the water content of the receiving groundwater store. Alternatively, a proportional split of runoff to fast (surface storage) and slow (groundwater) pathways can be invoked with no explicit soil drainage function. Recursive solutions to the Horton-Izzard equation are provided for routing flows through these pathways, conveniently considered to yield the surface runoff and baseflow components of the total flow. An alternative routing function employs a transfer function that is discretely-coincident to a cascade of two linear reservoirs in series. For real-time flow forecasting applications, the PDM is complemented by updating methods based on error prediction and state-correction approaches. The PDM has been widely applied throughout the world, both for operational and design purposes. This experience has allowed the PDM to evolve to its current form as a practical toolkit for rainfall-runoff modelling and forecasting.
Polarization of radio waves transmitted through Antarctic ice shelves

Abstract The polarization behaviour of radar waves transmitted through two Antarctic ice shelves has been investigated using a step frequency radar with a centre frequency of 300 MHz and a bandwidth of 150 MHz. One site was on Brunt Ice Shelf at a site near Halley station, and 17 sites were on George VI Ice Shelf near the southern ice front. Birefringence in the ice dominated the behaviour on Brunt Ice Shelf, where the anisotropy in the effective permittivity was found to be about 0.14%. On George VI Ice Shelf, a highly anisotropic reflecting surface was the controlling feature, suggesting a fluted ice-shelf base formed by oceanographic currents.
Helium isotope evidence for magmatic gases in Lake Nyos, Cameroon

We have measured ³He/4He and 4He/20Ne ratios of gas samples collected at Lake Nyos where a toxic gas disaster occurred on August 21, 1986 and at Lake Monoun in Cameroon, West Africa. The ³He/4He ratios, corrected for air contamination, are 5.39–5.75 Ratm (where Ratm is the atmospheric ratio of 1.40 × 10−6) for Lake Nyos and 3.56 Ratm for Lake Monoun. The data suggest a significant contribution of mantle-derived helium in these Cameroon volcanic crater lakes. The origin of CO2 gas “erupted” during Lake Nyos disaster is inferred to be of magmatic origin based on the high ³He/4He ratio.
Ventifacts – means to reconstruct glacial development and palaeo-environment in northern and central Sweden

Abstract Ventifacts occur frequently in extensive areas in northern and central Sweden. They arose during severe periglacial conditions in the Weichselian Tärendö interstadial and their presence indicates that the latest ice sheet was incapable of reshaping earlier deposits or even significantly after the interstadial ground surface in these areas. Accordingly, the ventifacts not only witness to harsh climatic conditions during part of the Tärendö interstadial but also reflect the limited erosional capacity of the latest ice sheet. Their significance as stratigraphic markers and means in the search for pre-Late Weichselian organic sediments, serving as archives for past climate and environment, is emphasized.
Does storm duration modulate the extreme precipitation‐temperature scaling relationship?

Predicting future precipitation extremes is difficult, and therefore, many studies have used the historical relationship between precipitation intensity and temperature to consider what might occur in a future warmer climate. In general, extreme precipitation intensity is expected to increase as temperatures increase. However, in tropical areas it has been observed that, for higher temperatures, lower precipitation intensities occur, contradicting the expected relationship. This has been thought to be due to limits in moisture availability. In this work we show that the negative scaling found in previous studies may be a result of the analysis methods. By conditioning the precipitation intensity and temperature relationship on storm duration, we demonstrate that positive scaling of precipitation intensity with temperature in tropical regions of Australia is possible. We argue that methods for estimating scaling relationships should be modified to include storm duration.
Cold ion beams in the low latitude boundary layer during accelerated flow events

Measurements made with the Fast Plasma Experiment on ISEE 1 and 2 reveal that accelerated beams of cold (1–30 eV for H+) ions are present sporadically on reconnected field lines within the low latitude boundary layer, LLBL. H+ normally is the major constituent of these beams, but He+ and O+ are also occasionally detected in variable concentrations. Because of the low temperatures and the compositional makeup of these beams, the ionosphere must ultimately be the source of these ions. Observed beam speeds (between 120 and 250 km s−1) are always less than that of the magnetosheath ions which penetrate into the LLBL on reconnected field lines, but both ion populations share the same E×B convective drift. Analysis reveals that reflection at the magnetopause cannot be the mechanism accelerating these ions. A more likely possibility is that the ions are accelerated primarily by the large transverse drift of recently reconnected field lines.
Earthquakes as multiscale dynamic ruptures with heterogeneous fracture surface energy

[1] We propose a model of the wide-scale growth of dynamic rupture during an earthquake, based on our multiscale simulation of a planar crack in a three-dimensional homogeneous elastic space. A simple slip-weakening law governs the fracture/friction processes, and its characteristic parameters, slip-weakening distance and fracture surface energy, have multiscale heterogeneous distributions. We consider a set of randomly distributed circular patches, whose diameter is proportional to the fracture surface energy. Each patch represents an asperity between irregular fault surfaces, and the size-number relation of the patches obeys power law statistics. We assess rupture propagation from a small instability using a boundary integral equation method with a renormalization technique. Although most events stop shortly after their initiation, some grow, triggering neighboring patches of similar size. Small and large events show statistically self-similar properties of rupture growth and stop spontaneously without requiring a special stopping mechanism. The rupture velocity locally exceeds the shear wave speed but globally remains subshear speed due to the increase of the average fracture energy as the rupture grows. The relation between size and frequency of events is a power law, which is explained by the triggering probability between patches. As a consequence of statistically self-similar random triggering growth, we observe a distinct “main phase” in seismic waves similar to those of natural earthquakes, but we cannot estimate the final size of the event from the initial part of the seismic waves. If this is true for the real earthquakes, predicting the size of a future earthquake would be quite difficult.
Radar backscatter analysis for urban environments

Abstract A full understanding of radar backscatter from urban areas is necessary in order to develop a robust methodology for monitoring and classifying urban characteristics using remotely sensed Synthetic Aperture Radar images.This paper examines the dominant backscattering mechanisms such as single bounce from roofs, double bounce from wall-ground structures and possibly triple bounce from wall-wall-ground structures, and their relative contributions to the backscatter. With the use of quad-polarized image data such as those acquired by the NASA/JPL AirSAR system, the backscatter can be decomposed into components caused by different backscattering mechanisms, offering a promise for urban monitoring and classification.
Time-reversal acoustics in complex environments

Time-reversal mirrors (TRMs) refocus an incident acoustic field to the position of the original source regardless of the complexity of the propagation medium. TRMs have now been implemented in a variety of physical scenarios from megahertz ultrasonics with aperture sizes of the order of centimeters to ocean acoustics at hundreds to thousands of hertz with aperture sizes of the order of hundreds of meters. Common to this broad range of scales is a remarkable robustness — exemplified by observations at all scales — that the more complex the medium between the probe source and the TRM, the sharper the focus. The relationship between the medium complexity and the size of the focal spot is studied in this paper. This relationship is certainly the most exciting property of TRM compared to standard focusing devices. A TRM acts as an antenna that uses complex environments to appear wider than it is, resulting in a broadband pulse with a refocusing quality that does not depend on the TRM aperture. In this paper, w.
A Numerical Model of the Depth-Dependent, Wind-Driven Upwelling Circulation on a Continental shelf

Abstract A numerical model of the upwelling circulation on a continental shelf is presented which employs f-plane dynamics. is continuously stratified, and assumes that all quantities are uniform alongshore with a local mass balance in the plane perpendicular to the coast at the seaward boundary. The model is an extension of the study by Allen (1973a) to include nonlinear effects, by the use of the complete conservation of density equation, variable shelf topography, and Richardson-number-dependent vertical eddy coefficients. A number of spinup experiments for a wind stress impulsively applied at t = 0 are discussed, to show that the width and strength of the coastal jet are dependent on the magnitude and form of the horizontal and vertical eddy coefficients as well as on details of the advective velocity field. Geostrophic shear in the longshore flow outside the coastal jet region, which may result in a poleward undercurrent, is only slightly altered by an upwelling event. Sloping shelf geometry intensif.