Miracle-dz/UniFAR-FTUs huggingface dataset:
Analysis of ordinary chondrites using powder X‐ray diffraction: 1. Modal mineral abundances

Abstract– Powder X‐ray diffraction (XRD) is used to quantify the modal abundances (in wt%) of 18 H, 17 L, and 13 LL unbrecciated ordinary chondrite falls, which represents the complete petrologic range of equilibrated ordinary chondrites (types 4–6). The XRD technique presents an effective alternative to traditional methods for determining modal abundances, such as optical point counting and electron microprobe phase (EMP) mapping. The majority of chondrite powders in this study were previously prepared for chemical characterization from 8 to 20 g of material, which is consistent with the suggested mass (10 g) necessary to provide representative sampling of ordinary chondrites. Olivine and low‐Ca pyroxene are the most abundant phases present, comprising one‐half to three‐fourths of total abundances, while plagioclase, high‐Ca pyroxene, troilite, and metal comprise the remaining XRD‐measured mineralogy. Pigeonite may also be present in some samples, but it is fitted using a high‐Ca pyroxene standard, so exact abundances cannot be measured directly using XRD. Comparison of XRD‐measured abundances with calculated Cross, Iddings, Pirsson, Washington (CIPW) normative abundances indicates that systematic discrepancies exist between these two data sets, particularly in olivine and high‐Ca pyroxene. This discrepancy is attributed to the absence of pigeonite as a possible phase in the CIPW normative mineralogy. Oxides associated with pigeonite are improperly allocated, resulting in overestimated normative olivine abundances and underestimated normative high‐Ca pyroxene abundances. This suggests that the CIPW norm is poorly suited for determining mineralogical modal abundances of ordinary chondrites.
Climatology and trends of wind speed in the Beaufort/Chukchi Sea coastal region from 1979 to 2009

Climatic records of wind speed are analyzed for eight long‐term monitoring locations in the Beaufort/Chukchi coastal region of the Arctic, over the period from 1979 to 2009. Data for this study originated from three national observing networks throughout the Beaufort/Chukchi region and were uniformly quality controlled using a combination of automated and manual checks. The climatology of wind speed was developed over the study period and includes analyses of mean wind speed, extremes, and frequency distributions. Trends in monthly and annual wind speed were examined. The climatology illustrates strong distinctions between coastal and interior locations, strong seasonal characteristics, and diurnal cycles in wind speed. Negative trends in wind speed were apparent at several locations, particularly at locations in Alaska. Many of these trends were statistically significant (95% CI). To assess the impact of artificial changes on trends, station data were homogenized with respect to metadata records. Trends were recalculated and the effects were discussed. Possible drivers of wind speed trends were also discussed, including multi‐decadal climate signals. Results from the climatology and trend analyses were compared with output from the North American Regional Reanalysis (NARR). Negative biases in wind speed were apparent at most locations throughout the year in NARR. Trends in NARR wind speed opposed in situ trends, at most locations. Improved knowledge of wind speed records and reanalysis output is important in this rapidly changing region.
Regulation of Pancreatic Amylase by Dietary Carbohydrate in Chronic Alcoholic Rats

The nutritional adequacy of dietary ingredients is essential for optimal food consumption and growth of animals. Dietary carbohydrate levels regulate pancreatic amylase synthesis. Ethanol diets with 36% of total calories from ethanol and 11% from carbohydrate are nutritionally inadequate, whereas a 26% ethanol diet made isocaloric to the 36% alcohol diet by the addition of maltose-dextrins provides all nutrients in amounts recommended for normal growth. Young rats fed the modified ethanol diet for 3 months consume 101.4 ml of diet daily compared to 66.5 ml by those on the 36% ethanol diet. In- creased food consumption results in (a) similar amounts of alcohol consumption (3.6 vs. 3.3 g/day), (b) a threefold enhancement in carbohydrate intake (5.1 vs. 1.7 g/day), and (c) a normal growth rate (6.7 vs. 3.1 g/day). Both the acinar content of amylase (20.2 ± 0.3 μg/mg of protein) and the acinar response to cholecystokinin-octapeptide in 36% ethanol diet-fed rats are significantly reduced compared to those of 26% ethanol diet-fed rats (34.1 ± 5.6 μg/mg of protein). These results confirm (a) the nutritional adequacy of the 26% ethanol diet compared to the 36% ethanol diet, and (b) that carbohydrate inadequacy, and not ethanol consumption per se, is the primary cause of pancreatic amylase insufficiency in chronic alcoholic rats.
Long-term El Niño-Southern Oscillation (ENSO)-like variation with special emphasis on the South Pacific

Mechanisms for El Nino-Southern Oscillation (ENSO)-like decadal (7–35 years) variability are analyzed using observational data. When a decadal positive temperature anomaly occurs in the eastern tropical Pacific, the atmospheric response excites negative wind stress curl in the western tropical South Pacific, which causes the thermocline to shoal and induce a negative temperature anomaly there. The cold anomaly moves northwestward to the western and central equatorial region and then turns eastward along the equator to reverse the original temperature anomaly in the east. The eastward propagation of the oceanic signal along the equatorial thermocline correlates with a zonal wind anomaly. The cold anomaly in the east grows through tropical air-sea interaction and induces a positive wind stress curl in the western tropical South Pacific associated with the atmospheric teleconnection in the Southern Hemisphere. Subsequent evolution of the negative phase is similar to that of the positive phase. The complete scenario for this ENSO-like decadal variability due to the air-sea interaction processes within the tropics has a period of ∼14 years. We also discuss ENSO-like variation on the interdecadal (>35 years) timescale, with possible relationship to the 1976–1977 climate regime shift.
Salinity‐induced hydrate dissociation: A mechanism for recent CH4 release on Mars

Recent observations of CH4 in the Martian atmosphere suggest that CH4 has been added relatively recently. Several mechanisms for recent CH4 release have been proposed including subsurface biological methanogenesis, abiogenic hydrothermal and/or volcanic activity, dissociation of CH4 hydrates, atmospheric photolysis, or addition of organics via bolide impact. This study examines the effects of increasing salinity on gas hydrate stability and compares estimates of the Martian geothermal gradient to CH4 and CO2 hydrate stability fields in the presence of high salinity brines. The results demonstrate that salinity increases alone result in a significant decrease in the predicted hydrate stability zone within the Martian subsurface and may be a driving force in CH4 hydrate destabilization. Active thermal and/or pressure fluctuations are not required in order for CH4 hydrates to be the source of atmospheric CH4.
A flume experiment on the effect of channel width on the perturbation and recovery of flow in straight pools and riffles with smooth boundaries

The scaling relation between channel width and the spacing of macroscale bed forms has long interested earth scientists and engineers. The current paper conceptualizes flow over such macro bed forms using perturbation theory. The objectives are to characterize the response of flow to pressure gradients that occur in convectively accelerating flow and convectively decelerating flow (CDF), as occurs in pools and riffles, and to determine how the response is modified by the width of the channel. Flume experiments are described that use idealized two‐dimensional bed forms and an inner movable wall to isolate the effect of channel width. Ultrasonic Doppler velocimetry profilers operating at 40 Hz are used to measure velocity. Results show that the recovery of the shear velocity (u*) and Coles wake parameter (Π) follows a simple relaxation response toward uniform flow conditions that is insensitive to channel width, while the lateral concentration of flow (Ψ) and the principal Reynolds stress ( −u′w′¯ ) occur as two‐stage spreading and relaxation responses that follow a scaling relation on the order of 3–4 times the channel width, or approximately one half of the typical distance between pools. The −u′w′¯ increases during CDF, precisely in the location where mean bed velocity is at a minimum. It thus appears that hydrodynamic recovery from perturbation helps to explain the sensitivity of the scale of macro bed forms in rivers to channel width. Mobile beds and 3‐D geometries should be tested to verify how mean flow and turbulent scales evolve as linked aspects of a complex response to perturbation.
Impact of neotectonics on the record of glacier and sea level fluctuations, strait of magellan, southern chile

ABSTRACT. This paper presents evidence for a neotectonic influence on Late Pleistocene/Holocene records of environmental change in the southern Strait of Magellan. We concentrate on one site, Puerto del Hambre, a key location for reconstructing palaeoenvironmental change in southernmost South America. We report geomorphological, structural geological, seismic and topographic data that all show the site has been affected by postglacial faulting. There is also indirect evidence from the site stratigraphy that the site has been displaced. Also, recent faulting explains some of the puzzles associated with interpretation of the palaeoenvironmental record at Puerto del Hambre. The implication of this work is that neotectonic faulting had a pervasive influence in the southern part of the Strait of Magellan and southernmost Tierra del Fuego, and thus affects glacial or sea level reconstructions in the area.
Limits on the validity of infinite length assumptions for modelling shallow landslides

The infinite slope method is widely used as the geotechnical component of geomorphic and landscape evolution models. Its assumption that shallow landslides are infinitely long (in a downslope direction) is usually considered valid for natural landslides on the basis that they are generally long relative to their depth. However, this is rarely justified, because the critical length/depth (L/H) ratio below which edge effects become important is unknown. We establish this critical L/H ratio by benchmarking infinite slope stability predictions against finite element predictions for a set of synthetic two‐dimensional slopes, assuming that the difference between the predictions is due to error in the infinite slope method. We test the infinite slope method for six different L/H ratios to find the critical ratio at which its predictions fall within 5% of those from the finite element method. We repeat these tests for 5000 synthetic slopes with a range of failure plane depths, pore water pressures, friction angles, soil cohesions, soil unit weights and slope angles characteristic of natural slopes. We find that: (1) infinite slope stability predictions are consistently too conservative for small L/H ratios; (2) the predictions always converge to within 5% of the finite element benchmarks by a L/H ratio of 25 (i.e. the infinite slope assumption is reasonable for landslides 25 times longer than they are deep); but (3) they can converge at much lower ratios depending on slope properties, particularly for low cohesion soils. The implication for catchment scale stability models is that the infinite length assumption is reasonable if their grid resolution is coarse (e.g. >25 m). However, it may also be valid even at much finer grid resolutions (e.g. 1 m), because spatial organization in the predicted pore water pressure field reduces the probability of short landslides and minimizes the risk that predicted landslides will have L/H ratios less than 25. Copyright © 2012 John Wiley & Sons, Ltd.
Effect of rising Asian emissions on surface ozone in the United States

The effect of increasing fossil fuel combustion in eastern Asia on surface O3 air pollution in the United States is examined with a global three‐dimensional tropospheric chemistry model. Tripling of Asian anthropogenic emissions from 1985 to 2010 is expected to increase monthly mean O3 concentrations by 2–6 ppbv in the western United States and by 1–3 ppbv in the eastern United States, the maximum effect being in April–June. This increase would more than offset the benefits of 25% domestic reductions in anthropogenic emissions of NOx and hydrocarbons in the western United States. Asian influence may be less under the stagnant conditions leading to violations of the U.S. air quality standard. Nevertheless, our results suggest that a global perspective is necessary when designing a strategy to meet regional O3 air quality objectives.
Geomechanics of subsurface water withdrawal and injection

Land subsidence and uplift, ground ruptures, and induced seismicity are the principal geomechanic effects of groundwater withdrawal and injection. The major environmental consequence of groundwater pumping is anthropogenic land subsidence. The first observation concerning land settlement linked to subsurface processes was made in 1926 by the American geologists Pratt and Johnson, who wrote that “the cause of subsidence is to be found in the extensive extraction of fluid from beneath the affected area. ” Since then, impressive progress has been made in terms of: (a) recognizing the basic hydrologic and geomechanic principles underlying the occurrence; (b) measuring aquifer compaction and ground displacements, both vertical and horizontal; (c) modeling and predicting the past and future event; and (d) mitigating environmental impact through aquifer recharge and/or surface water injection. The first milestone in the theory of pumped aquifer consolidation was reached in 1923 by Terzaghi, who introduced the principle of “effective intergranular stress. ” In the early 1970s, the emerging computer technology facilitated development of the first mathematical model of the subsidence of Venice, made by Gambolati and Freeze. Since then, the comprehension, measuring, and simulation of the occurrence have improved dramatically. More challenging today are the issues of ground ruptures and induced/triggered seismicity, which call for a shift from the classical continuum approach to discontinuous mechanics. Although well known for decades, anthropogenic land subsidence is still threatening large urban centers and deltaic areas worldwide, such as Bangkok, Jakarta, and Mexico City, at rates in the order of 10 cm/yr.
Zoning in highly alkaline magma bodies

Abstract We present chemical data on magmatically heterogeneous pyroclastic deposits of late Quaternary age erupted from zoned magma systems underlying Tenerife (Canary Islands), Sao Miguel and Faial (Azores), and Vesuvius. The most fractionated magmas present at each centre are respectively Na-rich phonolite, trachyte, and K-rich phonolite. Within any one deposit, chemical variation is either accompanied by changes in the phenocryst assemblage (petrographic zonation) or is largely manifested in trace element abundances, unaccompanied by any petrographic change (occult zonation). Zoning is analogous to that in calc-alkaline systems where the most fractionated products are high-silica rhyolites. When a range of magma types are considered, a correlation emerges between roofward depletion of trace elements (especially REE) in the zoned system and compatability of those same trace elements in the accessory phenocryst phases present. Thus, allanite- or chevkinite-bearing rhyolitic systems are light-REE depleted roofwards, the sphene-bearing Tenerife system is middle-REE depleted roofwards, the melanite-bearing Vesuvius system is heavy-REE depleted roofwards, while the Azores systems, which lack these phases, display roofward REE enrichment. Therefore, the behaviour of trace elements may in each case be explained by fractionation of observed phenocryst assemblages. The resemblance between features of zoned magma systems and published work on the dynamic consequences of cooling saturated aqueous solutions prompts us to suggest that sidewall crystallization and consequent boundary-layer uprise to form a capping layer at top of the system may be a plausible mechanism for the generation of both petrographic and occult zonation. Reverse zoning occurs among the first-erupted tephra of some deposits, demonstrating that the most highly differentiated magma available is not always the first to be tapped during an eruption from a zoned system.
On farm evaluation of the effect of crystallizer and soil conditioners on maize growth and yield in Niger State

This study was conducted to evaluate the effect of crystallizer and soil conditioners on maize growth and yield. Five locations were used. The farmers’ practice of growing maize was compared side by side with technology of crystallizer and boost extra application. The effects of the applied treatments to maize increase the growth and yield parameter of maize. With the recommended practice field maize vigour on the average for all locations 3 and for farmers practice field on the average was 5 , implying normal vigour and weak vigour respectively. Maize height at maturity on the average for all locations with recommended practice was 262.2 cm and farmers practice field was 228.1 cm. maize yield and it’s component showed a positive respond to all the treatments in terms of percentage increase effect of application as follows height at maturity 13.1, days to 50% tasselling 1.1 and grain yield (kg/ha) 25.6, implying significant increase in height and yield of maize. It is recommended that both farmers and farm managers alike should adopt the application of crystallizers and soil conditioners using recommended practices to ensure proper growth and to obtain optimum yield from maize. Keywords : Crystallizer, Soil conditioners, Maize growth and Yield Journal of Agriculture and Social Research (JASR) Vol. 11, No. 1, 2011
The relationship between the North Atlantic Oscillation and El Niño‐Southern Oscillation

We have applied a multiresolution cross‐spectral analysis technique to resolve the temporal relationship between the NAO and ENSO. The study shows significant coherence between NAO and Niño3 SST in about 70% of the warm ENSO events from 1900 to 1995, of which 33% and 37% are associated with a 5‐ to 6‐year period (E1) and a 2‐ to 4‐year period (E2) oscillation terms in the spectral decomposition, respectively. The dominant teleconnection pattern associated with changes in the mean atmospheric circulation during the initial winter of a typical E1 and E2 events is the positive phase of the Pacific/North American (PNA) pattern. Non‐coherence between the NAO and ENSO occurs during relatively weak Niño3 SST anomaly, with a teleconnection pattern which shows a strong negative phase of the NAO and a pattern which resembles a weak eastward shifted negative phase of the PNA pattern.
The Effect of Sea-Level and Climate Change on the Development of a Mixed Siliciclastic–Carbonate, Deltaic Coastline: Suwannee River, Florida, U.S.A.

Abstract Florida's mixed siliciclastic–carbonate, northwest-central Gulf of Mexico coastline is characterized by a 300-km-long, low-energy, sediment-starved, open-marine marsh system fronted by a broad, shallow limestone shelf. The only significant point source of sediment to this system is the Suwannee River, which forms a small (20 km2) delta at the center of this coastline. Late Pleistocene eolian dune formation along the Suwannee River coastline reflects slightly drier conditions and local sediment sources influencing the early geologic development of this region. As sea level rose in the early to middle Holocene, dunes on the low-gradient shelf were transgressed and provided the core for the modern offshore sandy shoals. With decelerating sea-level rise in the middle to late Holocene and probable increased riverine sediment input, coastal sedimentation switched from transgressive to aggradational. Paleo-distributary channels seaward of the delta coastline at approximately 4,000 cal yr BP indicate initial deltaic formation. At this same time, oyster reefs from the delta southward were able to keep pace with sea-level rise and began to form large (< 20 km2) offshore oyster bioherms. Away from the river mouth, the coastline continued to transgress until 2,350 cal yr BP to 1350 cal yr BP, when the shoreline stabilized and the modern marsh system, south and north of the river mouth respectively, began to aggrade. The geologic development of this coastline and the relict eolian dunes preserved within the modern marsh system indicates that middle to late Holocene sea level did not exceed current elevations along this portion of the Gulf of Mexico coastline. This finding agrees with other studies from the low-gradient west-central Florida coast but contrasts with evidence for middle to late Holocene highstands along other Gulf of Mexico shorelines.
EXPERIMENTAL INVESTIGATION OF INTERACTIONS BETWEEN BLUNT FIN SHOCK WAVES AND ADJACENT BOUNDARY LAYERS AT MACH NUMBERS 3 AND 5.

Abstract : Strong interactions between fin generated shock waves and laminar and turbulent boundary layers are investigated using cylindrically blunt, slab type fins mounted at various streamwise stations on a sharp leading edge flat plate. Surface pressure distributions, total pressure rake surveys, and schlieren oil film and sublimation photographs are obtained for Mach 3 and Mach 5 flows. Reynolds numbers, based on free stream conditions and the length of the plate ahead of the fin leading edge, vary from 0.1 to 4.8 million. The separated flows resulting from the interaction are highly vortical in nature. Nevertheless, in the plane of symmetry, the separated flows ahead of the fin bow shocks resemble two-dimensional separated flows; the laminar plateau and turbulent peak pressures can be estimated using expressions developed for two-dimensional separated flows. The extent of laminar separation ahead of the fin increases with increasing Reynolds number; turbulent separation is insensitive to Reynolds number and occurs approximately two diameters upstream of the fin leading edge. The separated flows and interaction regions scale with fin diameter for diameters greater than or approximately equal to the local boundary layer thickness. (Author)
Evidence for shallowing and uplift from bathymetric records of Deception Island, Antarctica

Deception Island is a large volcanic centre in Bransfield Strait, a very young marginal basin between the South Shetland Islands and Antarctic Peninsula. It has a historical record of volcanic activity, with the most recent eruption occurring in 1970. The island is a stratovolcano with a large flooded caldera forming a natural harbour known as Port Foster. It has been a focus of human activity since early last century, as a base for whaling and sealing expeditions and the locus of several scientific stations. During that period, many bathymetric surveys were carried out, the earliest in 1829 and the most recent in 1993. This study concentrates on surveys from 1948 onwards. Because Port Foster can be classified as a restless caldera, the bathymetric records were analysed for evidence of volcano-tectonic deformation, particularly caldera resurgence (uplift) which could have significant consequences for hazard and risk assessments of the volcano. The results show that a distinctive pattern of shallowing and uplift is present, correlating well with known and inferred volcanic and volcanotectonic processes on the island. In particular, bathymetric records between 1949 and 1993 show uplift rates as high as 0.3–0.5 m a−1, far exceeding normal sedimentation rates in a caldera this size. Rapid uplift in an arcuate offshore area not affected by the sedimentation of recent eruptions suggests that volcano tectonic resurgence or tectono-magmatic effects of an upward migrating magma chamber present a significant risk to the considerable human activity taking place in the region.