Miracle-dz/UniFAR-FTUs huggingface dataset:
Properties of He+ beams observed by Geotail in the lobe/mantle regions: Comparison with O+ beams

In the lobe/mantle regions of Earth's magnetotail (<210 RE), the Geotail spacecraft sometimes observed multicomposition ion flows consisting of both ionospheric (H+/He+/O+) and solar wind (H+/He++) ions. Statistics on the He+ beams show that they were observed under similar conditions to those of the O+ beams reported previously. Namely, the heavy ion beams of ionospheric origin tend to exist during geomagnetically active periods in the mantle-like regions of high plasma beta, where ions of solar wind origin are the major component. The total duration of identified He+ events amounts to 3% of the total observation time in the lobe/mantle region, while that of O+ events amounts to 13%. A remarkable point is that on a short timescale, the He+ and O+ beams often appear to exist nearly exclusively. That is to say, their densities sometimes vary in an opposite sense, even when He+ and O+ coexist. If the O+ and He+ ions are given the same energy in a source region, the initial distribution function of He+ has twice the peak velocity of that of O+, and their alternating appearance and density anticorrelation in the lobe/mantle are easily explained due to the velocity filter effect. Thus the anticorrelation of their densities may suggest that ionospheric ions have undergone an energization which leads to a different velocity for different ion species. A mechanism leading to the same velocity, on the other hand, would require an alternating enhancement of the He+ and O+ fluxes in a source region to explain the anticorrelation of the densities.
Equilibration and Lateral Spreading of a Strip-Shaped Convective Region*

Abstract The authors investigate the spreading stage of the deep ocean convection for a strip-shaped convective region to study the law of spreading and sensitivity of the eddy exchange efficiency parameter to the shape of the region and the background stratification. To simulate this convection process a two-layer quasigeostrophic model is used and the input of buoyancy due to surface cooling is parameterized through creation of pairs of baroclinic point vortices with opposite signs of potential vorticity (hetons) at a constant rate. It is shown that the eddy exchange efficiency parameter for lateral fluxes of potential density out of the convective region is not universal but essentially depends on the shape of the region and the relative layer thicknesses. The horizontal spreading of the potential density anomaly shows a faster than diffusive, quasi-linear dependence on time at moderate values of the surface buoyancy flux. This behavior is due to the specific dynamics of hetons and heton clusters.
Relationship between water retention capability and osmotic adjustment in sorghum (sorghum bicolor) grown under drought stress

Drought resistance of two drought‐resistant lines, GP12.IC 1039 and GP.20 Bagdar, and two drought‐sensitive lines, GPD11 YSS.89 and GP17.S. 35, of sorghum was assessed in a pot experiment under glasshouse conditions. Twenty‐eight‐day‐old plants of these four lines were subjected to repeated drought cycles for 15 days. The drought‐resistant lines were superior to the drought‐sensitive lines in biomass production and leaf area under drought stress. The drought treatment caused a significant reduction in leaf osmotic potential in all four lines. A close relationship between drought resistance and osmotic adjustment was observed in these lines differing in drought resistance. For instance, the two drought‐resistant lines had significantly higher osmotic adjustment (0.469 and 0.496 MPa) than that of the two drought‐sensitive lines (0.428 and 0.310 MPa). By contrast, a negative relationship between drought resistance and water retention capability (determined as decrease in weight of excised leaves during 5‐hour.
Diagenesis of magnetic mineral assemblages in multiply redeposited siliciclastic marine sediments, Wanganui basin, New Zealand

Abstract In many sedimentary environments, early diagenetic sulphidization reactions cause extensive dissolution of detrital magnetic minerals which can alter or destroy the palaeomagnetic signal. Pliocene sediments from the Wanganui basin, North Island, New Zealand, have been subjected to multiple cycles of erosion and redeposition in sulphatereducing environments before reaching their present setting. Despite this, the sediments retain a measurable and stable remanent magnetization. The only Fe-Ti oxide recognized from detailed sedimentary petrographic characterization of magnetic extracts and bulk sediments is ilmenite, with compositions that lie within the range from which paramagnetic behaviour is expected. There are no Fe-Ti oxide grains with compositions from which ferrimagnetic behaviour is expected (except for rare chromite). A direct link was made between magnetic behaviour and mineralogy by conducting electron probe microanalysis and back-scattered electron imaging of the same grains that were subjected to magnetic analysis. These studies demonstrate that stable magnetic behaviour is displayed by grains that appear to be homogeneously composed of ilmenite. This magnetic behaviour is attributed to the presence of ferrimagnetic Fe-enriched (hemo-ilmenite) microstructural domains that have been previously reported from ilmenite grains. These hemo-ilmenite domains appear to be dominantly responsible for the remanence of the Wanganui basin Pliocene sediments. Calculations of the reactivity of detrital iron-bearing minerals to sulphidization indicate that ilmenite is much less reactive than magnetite and other detrital magnetic minerals. Given the resistance of hemo-ilmenite, to dissolution, it is suggested that microstructural ferrimagnetic domains within ilmenite grains may be a source of palaeomagnetic information in sediments that have undergone diagenetic magnetic mineral dissolution during multiple episodes of erosion and redeposition.
Aerosol optical depth over land: Comparing AERONET, AVHRR and MODIS

Data from NOAA‐16 AVHRR have been used to retrieve the spatial distribution of aerosol optical depth for central Europe. At eight AERONET sites, monthly mean values based on daily AVHRR aerosol maps are calculated and compared to monthly mean values from TERRA‐MODIS, AQUA‐MODIS and AERONET. Additionally, seasonal mean maps for 2002 are presented. To estimate the performance of this algorithm, the winter and summer season maps are compared to TERRA‐MODIS seasonal maps created from the daily global aerosol product. In general, the AVHRR and MODIS aerosol maps show the same features: Lower values with increasing altitude, higher values in heavily industrialized areas and overall reasonable mean values. AVHRR maps are spatially more homogeneous than MODIS, which seem to contain an imprint of the surface cover type. The maps clearly demonstrate the potential of the retrieval method to produce a climatology based on AVHRR aerosol optical depth data over land.
Extratropical cyclones, frontal waves, and Mars dust: Modeling and considerations

A Mars GCM is utilized to investigate dust lifting and organization associated with extratropical cyclogenesis and frontal waves. The model is applied at high resolution in simulations related to Mars' dust cycle. A single extratropical synoptic weather event is examined to ascertain lifting, transport and convergence/divergence of dust by large‐scale cyclonic/anticyclonic weather systems, and the sub‐synoptic frontal waves that ensue. Low‐ and high‐pressure cores develop, travel eastward and remain mostly confined within the seasonal CO2 polar cap. The bulk of dust lifting occurs in the northern‐hemisphere western highlands associated with nocturnal down‐slope drainage flows, and lifting infrequently occurs near the frontal convergence zone. Dust becomes organized and transported within circulations associated with the synoptic/sub‐synoptic circulations accompanying the frontal waves. Dynamical considerations are invoked regarding frontogenesis revealing correlations with regards to dust lifting, organization and transport. Implications of large‐scale extratropical weather systems on the martian dust cycle are discussed.
Detrital Zircon Geochronology of Taconian and Acadian Foreland Sedimentary Rocks in New England

ABSTRACT U-Pb ages of detrital zircons in lower Paleozoic sedimentary rocks from New England permit evaluation of the relationships between tectonic activity and provenance of foreland sediments deposited in response to the Taconian and Acadian orogenies. The Lower Cambrian Poughquag Quartzite was deposited on the Laurentian passive margin. Poughquag detrital zircons (n = 40) are mostly concordant to slightly discordant with 207Pb*/206Pb* ages of 1.67-0.87 Ga and are consistent with a provenance from the nearby Grenville Structural Province. Two Poughquag zircon grains record 206Pb*/238U ages of about 0.64 Ga and 0.55 Ga and could have been derived from rift-related magmatic rocks. The Middle Ordovician Austin Glen Member of the Normanskill Formation and Lower Silurian Shawangunk Formation represent clastic-wedge sedimentation in the Laurentian foreland deposited in response to the Taconian orogeny (ca. 470-430 Ma). Zircons from these units (n = 41 for Austin Glen, n = 29 for Shawangunk) are also predominantly of Grenville age (207Pb*/206Pb* ages of 1.46-0.94 Ga). One zircon from the Austin Glen records an age of 3.29 Ga, consistent with derivation from North American Archean terranes. No zircon from either unit (or reported in the literature) can be interpreted as recording an Ordovician (Taconian) age. Devonian Catskill "redbeds" represent synorogenic to postorogenic foreland sedimentation associated with the Acadian orogeny (ca. 400-360 Ma). Zircons from one sample (n = 45) are all near concordant and have a bimodal age distribution. Approximately 60% of grains have 207Pb*/206Pb* ages of 1.23-1.00 Ga and the other 40% have 206Pb*/238U ages of 0.47-0.42 Ga. Very different proportions of Precambrian and Paleozoic ages are seen in the Catskill sample if zircons are selected on the basis of size or optical clarity, and this observation highlights the possibility of sampling bias if detrital zircons are not randomly selected for U-Pb analysis. The 0.47-0.42 Ga population is consistent with derivation from rocks crystallized during the Taconian orogeny. No analyzed zircon in this sample records an unambiguous Devonian (Acadian) age. Accordingly, during early Paleozoic evolution of the Laurentian foreland basins in New England, detrital zircons do not appear to record contemporaneous orogenic activity but instead are restricted to recycling of the preexisting continental margin. It is possible that substantial topography (e.g., accretionary prism) impeded sediment transport from the active orogen to the foreland basin.
An exceptional winter sea‐ice retreat/advance in the Bellingshausen sea, Antarctica

Abstract The exceptional sea‐ice retreat and advance that occurred in the Bellingshausen Sea, Antarctica during August 1993 was the largest such winter event in this sector of the Antarctic during the satellite era. The reasons for this fluctuation of ice are investigated using passive microwave satellite imagery, ice motion vectors derived from the satellite data, in‐situ meteorological reports and near‐surface winds and temperatures from the European Centre for Medium‐range Weather Forecasts (ECMWF) numerical weather prediction model. The ice edge retreat of more than 400 km took place near 80°W from approximately 1–15 August, although the southward migration of the ice edge was not continuous and short periods of advance were also recorded. Between 16 August and 2 September there was almost continuous sea‐ice recovery. The rate of change of the ice edge location during both the retreat and advance phases significantly exceeded the southward and northward velocity components of ice within the pack, pointing to the importance of ice production and melting during this event. During the month, markedly different air masses affected the area, resulting in temperature changes from +2°C to ‐21°C at the nearby Rothera station. ‘Bulk’ movement of the pack, and compaction and divergence of the sea ice, made a secondary, but still significant, contribution to the observed advance and retreat. The ice extent fluctuations were so extreme because strong meridional atmospheric flow was experienced in a sector of the Southern Ocean where relatively low ice concentrations were occurring. The very rapid ice retreat/advance was associated with pronounced low‐high surface pressure anomaly couplets on either side of the Antarctic Peninsula.
A design approach for selecting the optimum water cover depth for subaqueous disposal of sulfide mine tailings

The use of shallow water covers to flood reactive mine tailings is one of the most effective and common methods of managing sulfide-rich reactive mine tailings in temperate climates. One of the aspects critical to the success of subaqueous tailings disposal is the water depth required in the pond to maintain desirable water quality. Wind waves and associated pressure-driven currents could resuspend the tailings, which might result in increased oxidation and compromise the quality of the water cover. Although existing methodologies for water cover design are based on eliminating tailings resuspension, sediment-trap data from several sites in Canada still indicate resuspension in most of the ponds. In the present paper, a design methodology is proposed for optimizing the water cover depth, allowing sediment resuspension within regulatory limits. The method uses linear wave theory and countercurrent flow profiles to obtain the total bottom shear stress, which is then compared with the critical shear stress o.
Characterization of Undrained Behaviour of Soils in the Reclaimed Area of Kobe

ABSTRACT Studies on the undrained behaviour of Masado soil, a fill material which was chiefly responsible for the massive liquefaction in the reclaimed areas of Kobe city during the Hyogoken-Nambu earthquake, are presented. Results from multiple series of triaxial tests are used as a basis for behavioural characterization within the framework of the state concept. Reconstituted samples of three Masado soils with different gradation curves were used together with undisturbed samples recovered from Kobe Port Island to investigate the effects of the grain-size distribution, soil fabric, initial e-p' state (void ratio-confining stress state) and mode of loading on the undrained behaviour. The location of the steady state line in the e-p' diagram was found to be related chiefly to the gradation of the Masado soils. However, a unique pair of zero residual strength line and steady state line was found to exist in a modified e-p' diagram regardless of the gradation curve, fabric of the soil and mode of loading. It is shown that the state index Is can be used to quantify the undrained behaviour when using these characteristic states as frames of reference. A procedure is proposed which enables an assessment to be made of the in-situ void ratio and undrained behaviour throughout the depth of a reclaimed deposit if the gradation curve of the fill material is known.
Transient climate response to external forcing on 100–104 year time scales part 1: Experiments with globally averaged, coupled, atmosphere and ocean energy balance models

We present the results of a study of the sensitivity of the transient surface temperature response to a step function solar constant increase using a globally averaged energy balance climate model which is coupled to two different globally averaged thermodynamic ocean models. The first ocean model is a box model, in which the ocean is divided into a small number of isothermal reservoirs. Experiments with this model demonstrate some circumstances in which it is important to treat the mixed layer and deep ocean separately rather than lumping them into a single reservoir, as has been the practice in a number of recent studies using coupled atmosphere-ocean-cryosphere models over 104 year time scales. The second ocean model has an isothermal mixed layer which is coupled to an advective-diffusive deep ocean having a continuous vertical temperature profile. We permit the thermal diffusivity K and the advection velocity w to vary vertically and introduce a variety of plausible feedbacks between K and the vertical temperature gradient, and between w and the perturbation mixed layer wanning. We also permit the bottom water source temperature to change by a prescribed fraction of the mixed layer response. The transient surface response is relatively insensitive to changes in K and w for the nonfeedback cases, but is more sensitive to individual feedback mechanisms. When multiple feedback processes are permitted a complex transient surface temperature response is possible. When applied with a periodic solar constant forcing, these feedback processes can either significantly reduce or increase the amplitude of the surface temperature response compared to the no-feedback case.
Exposición a mercurio en trabajadores de una mina de oro en el norte de Colombia

Objective: We evaluated mercury exposure through a biomarker of exposure in a gold mine in northern Colombia. Materials and Methods: Analysis of Hg - T was performed cold vapor atomic absorption spectroscopy (CVAAS) in a population of workers in the mine Alacran (department of Cordoba - Colombia) Results: The levels of Hg - T in urine are around 3.16 pig/L. and 339.15 pig/L. The high values of Hg in urine is due to occupational exposure of workers in artisanal gold mine where metallic mercury is used for the recovery of precious metal. The 28.6% of the samples of the mine workers Alacran exceded those recommended level by the World Health Organization (20 pig / L). Conclusions: Contained mercury levels in urine samples show a potential risk to the health of the mine workers Alacran due to occupational exposure this metal in the process of amalgamation of Gold With the results obtained in this investigation are seeks to implement management plans for the prevention, aimed at reducing the risk factors on the health of populations living in the mine the Alacran.
Soufrière Hills Eruption, Montserrat, 1995–1997: Volcanic earthquake locations and fault plane solutions

A total of 9242 seismic events, recorded since the start of the eruption on Montserrat in July 1995, have been uniformly relocated with station travel‐time corrections. Early seismicity was generally diffuse under southern Montserrat, and mostly restricted to depths less than 7 km. However, a NE‐SW alignment of epicentres beneath the NE flank of the volcano emerged in one swarm of volcano‐tectonic earthquakes (VTs) and later nests of VT hypocentres developed beneath the volcano and at a separated location, under St. George's Hill. The overall spatial distribution of hypocentres suggests a minimum depth of about 5 km for any substantial magma body. Activity associated with the opening of a conduit to the surface became increasingly shallow, with foci concentrated below the crater and, after dome building started in Fall 1995, VTs diminished and repetitive swarms of ‘hybrid’ seismic events became predominant. By late‐1996, as magma effusion rates escalated, most seismic events were originating within a volume about 2 km diameter which extended up to the surface from only about 3 km depth ‐ the diminution of shear failure earthquakes suggests the pathway for magma discharge had become effectively unconstricted. Individual and composite fault plane solutions have been determined for a few larger earthquakes. We postulate that localised extensional stress conditions near the linear VT activity, due to interaction with stresses in the overriding lithospheric plate, may encourage normal fault growth and promote sector weaknesses in the volcano.
The Role of Peat Layers on Iron Dynamics in Peatlands

The Role of Peat Layers on Iron Dynamics in Peatlands (A Fahmi, B Radjagukguk, BH Purwanto and E Hanudin): The research aimed to study the effect of peat thickness and humification stage of the peat material on Fe solubility at the peatlands with sulfidic material as substratum. The research was conducted at three conditionals of ombrogen peatlands ie ; deep, moderate and shallow peat. Soil samples were collected by using peat borer according to interlayer (the border layer of peat and mineral layer) and conditional of soil horizons. The sample point depth were (cm) G.s2 : 25, G.s1 : 50, Int.s : 70, M.s1 : 90 and M.s2 : 100 for shallow peat, G.m2 : 47, G.m1 : 100, Int.m : 120 and M.m1 : 135 for moderate peat and G.d3 : 50, G.d2 : 150, G.d1 : 200, Int.d : 220 and M.d1 : 235 for deep peat respectively. The results showed that most of Fe on the tested soils was found in organic forms. The peat layers above the sulfidic material decreased the Fe2+ solubility at peatlands. Fe2+ concentration in peat layer decreased with its increasing distance from sulfidic material. There was any other processes beside complexation and chelation of Fe2+ by humic material and its processes was reduction of Fe3+ and this conditions was reflected in redox potential values (Eh).
Effect of Lee‐Wake on Scour Below Pipelines in Current

The results of an investigation of the effect of lee‐wake on scour below pipelines in currents are reviewed. The subject is investigated both experimentally and numerically. The experiments show that the scour downstream of the pipe is apparently governed by the action of an organized wake flow, which is an agglomeration of large‐scale vortices which are shed from the pipe and steadily convected downstream. The experimental results lead to a clear understanding of the effect of lee‐wake on the scour phenomenon. In the numerical part of the study the so‐called cloud‐in‐cell method is employed to predict the flow. The results appear to reveal almost all the features of the organized wake flow shown by the experiments. The theoretical calculations demonstrate that the time average bed shear stress is not a suitable parameter to work with in mathematical‐model studies of lee‐wake scour.
Center of the Iceland hotspot experiences volcanic unrest

A volcanic eruption beneath the Vatnajokull ice cap in central Iceland (Figure 1) began on September 30,1996, along a 7-km-long fissure between the volcanoes Bardarbunga and Grimsvotn. The eruption continued for 13 days and produced ˜0.5 km3 of basaltic andesite. Meltwater from the eruption site flowed into the caldera lake of the Grimsvotn volcano, where it accumulated beneath a floating ice shelf. The lake's ice dam was lifted off the glacier bed on November 4, and in the next two days more than 3 km3 of water drained out beneath the glacier and flushed down to the south coast's alluvial plain, causing extensive flooding and damage to transportation and communication systems.