Miracle-dz/UniFAR-FTUs huggingface dataset:
Conservation Tillage for Climate Change Mitigation – The Reality

Conservation tillage as part of the solution to mitigate climate change effects and to ensure sustainable agriculture, was initially promoted to reduce soil erosion and improve soil organic matter content and water storage. The advantages of conservation tillage practices over conventional tillage include (1) reducing cultivation cost (2) allowing crop residues to act as an insulator and reducing soil temperature fluctuation (3) building up soil organic matter, and (4) conserving soil moisture. The conservation tillage practices result favourable changes in soil physical properties, such as bulk density, water holding capacity, pore size distribution, and aggregation. Stratification of soil organic matter and differences in nutrient distribution has also been observed in long-term conservation tillage systems. Conservation agriculture changes soil properties and soil processes compared to conventional agriculture. These changes can, in turn, affect the delivery of ecosystem services, including climate regulation through carbon sequestration and greenhouse gas emissions, and regulation and provision of water through modification in soil physical, chemical and biological properties. The benefits of conservation tillage in climate change mitigation primarily come from increased soil C sequestration. However, there are conflicting reports to this effect. Hence, this review addresses the potential and limitations of conservation tillage for soil carbon sequestration and trace gas fluxes and the possible mechanisms involved.
Procedures used to obtain soil parameters for foundation engineering in the North Sea

It is difficult and expensive to perform high‐quality soil investigations for platforms and pipelines offshore in deep waters and restless seas. This is especially true in the North Sea where the “weather window”; is small, and careful planning and timing of the soil investigation is essential. Field equipment, drilling, sampling and in situ soil testing procedures are described herein. The need for some laboratory testing on‐board, run simultaneously with the sampling operation, is stressed, and the sample handling and laboratory testing procedures used on‐shore are described and evaluated. The state of the art is discussed, and some future trends and desirable developments outlined.
Response to CO2 transient increase in the GISS coupled model : Regional coolings in a warming climate

Abstract The GISS coupled atmosphere–ocean model is used to investigate the effect of increased atmospheric CO2 by comparing a compounded 1% CO2 increase experiment with a control simulation. After 70 yr of integration, the global surface air temperature in the 1% CO2 experiment is 1.43°C warmer. In spite of this global warming, there are two distinct regions, the northern Atlantic Ocean and the southern Pacific Ocean, where the surface air temperature is up to 4°C cooler. This situation is maintained by two positive feedbacks: a local effect on convection in the South Pacific and a nonlocal impact on the meridional circulation in the North Atlantic. The poleward transport of latent energy and dry static energy by the atmosphere is greater in the 1% CO2 experiment, caused by warming and therefore increased water vapor and greater greenhouse capacity at lower latitudes. The larger atmospheric transports tend to reduce upward vertical fluxes of heat and moisture from the ocean surface at high latitudes, whi.
Formation and deposition of volcanic sulfate aerosols on Mars

Sulfurous gases released at the surface of Mars during episodes of volcanic activity would be naturally transported into the upper levels of the Martian atmosphere (20- to 30-km altitude) owing to the synoptic convergence of lower-level winds in the Tharsis region of the planet. The circulation of the upper atmosphere would globally disperse such gases over time scales of 25 earth days. The rate limiting step in sulfate aerosol formation on Mars is inferred to be the gas phase oxidation of SO2 which is accomplished via chemical reactions with O, OH, and HO2. Under present-day atmospheric conditions aerosol formation would occur over periods of several thousand earth days. However atmospheric concentrations of odd hydrogen species (OH, HO2) should increase significantly during periods of persistent surface volcanism. Under these circumstances sulfate aerosol formation could occur on time scales of several hundred earth days. Submicron-sized aerosol particles would circuit Mars several dozen times before they are removed from the atmosphere by gravitational forces. Such aerosols would be globally dispersed and would be deposited over a wide range of equatorial and mid-latitudes. Volcanic sulfate aerosols on Mars are inferred to consist of liquid droplets and liquid-solid slurries containing aqueous solutions of sulfuric acid. These acidic solutions would be chemically reactive and would trigger leaching processes within surface materials upon deposition. Sulfate aerosol deposition is a viable mechanism for transporting sulfur to the Viking lander sites. Atmospheric circulation models indicate that time-averaged vertical winds over Chryse Planitia and Utopia Planitia are directed toward the surface during most Martian seasons. Aerosol particles settling out of the atmosphere would be expected to be preferentially deposited in these regions. Aerosol deposition on a global or hemispheric scale could account for the similar concentrations of sulfur within surficial soils at the two Viking lander sites.
On modeling the mechanisms that control in‐stream phosphorus, macrophyte, and epiphyte dynamics: An assessment of a new model using general sensitivity analysis

The “Kennet model” is a new model of in‐stream phosphorus (P) and macrophyte dynamics. Based on mass balance equations, the model represents the interactions between P and the suspended and bed sediments, the uptake of P by epiphytes and macrophytes, and the exchange of P between the water column and the pore water. The model simulates the total phosphorus (TP) and the soluble reactive phosphorus (SRP) concentrations observed in a reach of the River Kennet. Furthermore, the model simulates the generalized macrophyte growth patterns and total biomass observed in rivers throughout southern England. A general sensitivity analysis, based on Monte Carlo simulations and parameter values derived from the literature, identifies the key parameters controlling the model behavior when simulating macrophyte growth. The most important parameters are those that directly control macrophyte growth, those that define the epiphyte growth, and those that relate to the storage of P in the streambed
Investigation of porosity and permeability effects from microstructure changes during limestone dissolution

We studied experimentally the dissolution of a porous limestone core during CO2‐enriched water injection. We measured the changes in porosity and permeability arising from modifications of the pore network geometry and the fluid‐rock interface. A methodology based on periodic X‐ray microtomography imaging was implemented to record the evolution of the time‐ and scale‐dependent microstructures with a spatial resolution of 4.91 μm. Two processes were successively involved in the rapid permeability increase of the sample, as documented from microscale to core‐scale measurements. First, the microcrystalline phase was partially dissolved, associated with displacement of mineral particles. During this process, the exponent n of the power law k ∼ ϕn decreased continuously. Secondly the sparitic phase dissolved, accompanied by a decrease of the pore wall roughness and an increase of the pore connectivity. This second period was characterized by a constant value of n. The reactive surface decreased noticeably during the transition from the microcrystalline to the sparitic dissolution periods, whereas the effective porosity increased strongly.
Shear strength behaviour of polypropylene fibre reinforced cohesive soils

Soil reinforcement through the inclusion of oriented or randomly distributed discrete elements such as fibres has recently attracted increasing attention in geotechnical engineering. Therefore, the purpose of this paper is to investigate the influence of certain parameters (the strength properties of the fibre, the relative size of the fibres and grains, and the rate of shear) on the shear strength of polypropylene fibre reinforced cohesive soils. A series of consolidated drained or undrained direct shear tests were conducted on unreinforced and reinforced sandy silt and silty clay specimens. Two types of polypropylene fibres with different mechanical indices were used. The fibre content was varied between 0.3% and 1.1% by weight of dry soil. The test results revealed that the inclusion of fibres in soil significantly increases the shear strength. The attainment of the high shear strength is attributed to the micromechanisms involved in the fibre/soil interactions as studied through scanning electron micrographs. The results also showed that the reinforcement effect was more pronounced under undrained shearing conditions. An important outcome from the current work is that, from the data obtained, the strength of the reinforced soil composites is not practically affected by the fibre mechanical indices.
Simulation of Ground Motion in the Zagros Region of Iran Using the Specific Barrier Model and the Stochastic Method

Abstract Physically based ground‐motion prediction equations for soil and rock sites in the Zagros region have been developed based on the specific barrier model (SBM) used within the context of the stochastic model. Instead of direct time‐domain simulation, random vibration theory was used to estimate measures of peak motion in terms of the pseudospectral velocity of anelastic harmonic oscillator with 5% viscous damping. To avoid the uncertainties, calibration of the source model uses a database of carefully selected strong motion data without ambiguity about the site condition. Therefore, only rock sites are selected for determining source parameters. Also, to avoid any inconsistencies caused by magnitude conversion formulas, we restricted the dataset only to events with available moment magnitudes. Regression analysis is performed using the random effects model that considers both interevent and intraevent variabilities to effectively deal with the problem of an unequal number of records from different earthquakes. No sign of self‐similarity breakdown is observed between the source radius and its seismic moment. The local and global stress drops derived for the Zagros region (39 and 116 bars, respectively) are more consistent with the values obtained by other authors for an interplate regime than the values for an intraplate region. However, from the viewpoint of source heterogeneity (as the ratio of the stress drops is an indicator of the complexity of the source and heterogeneity of slip on the fault) the Zagros events, which have a stress‐drop ratio of about three are more homogeneous than other interplate events. Stochastic simulations are then implemented to predict peak ground motion and response spectra parameters for rock and soil site conditions. Online Material: Catalog tables of earthquakes and attenuation tables.
Effects of Clearcutting and Slash Burning on Streamwater Chemistry and Watershed Nutrient Budgets in Southwestern British Columbia

Two small forested watersheds near Haney in southwestern British Columbia were partially clearcut, and the slash on one of them was subsequently burned. Streamwater chemistry was monitored in these treated watersheds and an undisturbed control watershed for 2 years prior to treatment and up to 9 years after treatment. The chemical parameters that were studied responded differently to the treatments, but there was a general pattern of increased concentrations and fluxes in Streamwater for the first 2–3 years following treatment followed by a decline to, and sometimes below, pretreatment values. The most pronounced increases were observed for K and NO3. It was not possible to determine the exact causes of these changes in concentrations and fluxes, due to the great variability in the ecosystems present. This variability precluded determination of statistically significant changes in annual terrestrial nutrient fluxes and pools. Stream nutrient exports usually were <10 kg/ha/yr for each of N, P, K, and Mg, <20 kg/ha/yr for Na and Cl, and <30 kg/ha/yr for Ca. These values were considerably less than nutrient exports in harvested logs and in losses to the atmosphere during the slashburn. Clearcutting and burning caused greater nutrient losses than Clearcutting alone, particularly in the case of N, where the Clearcutting and Clearcutting and burning treatments resulted in total losses of 245 kg/ha and 1293 kg/ha, respectively, for the first two years after treatment.
The Cenomanian-Turonian Oceanic Anoxic Event, II. Palaeoceanographic controls on organic-matter production and preservation

Summary Correlation of the δ13C spike with the well dated occurrences of strata rich in organic carbon detailed in Schlanger et al. (this volume), indicates that a global episode of intense organic carbon (orgC) burial took place during the latest Cenomanian-earliest Turonian ‘Oceanic Anoxic Event’ (OAE) (A. plenus through I. labiatus macrofossil zones and upper R. cushmani TRZ through W. archecretacea PRZ foraminiferal zones) over a period of no more than 1 million years (m.y.). The shape of the δ13C curve indicates that rates of orgC burial gradually increased in the early part of the late Cenomanian, increased more rapidly in the later Cenomanian, and levelled off at peak values in latest Cenomanian-early Turonian time during the maximum rate of orgC burial. The δ13C values decreased nearly to pre-late Cenomanian levels in the early to middle Turonian. The decrease in δ13C reflects decreasing rates of orgC burial following the Cenomanian-Turonian ‘oceanic anoxic event’ as well as the probable oxidation and return of significant amounts of orgC to the oceans following regression and re-oxygenation of much of the deeper water masses in contact with the seafloor. The Cenomanian-Turonian OAE coincided with a maximum sea level highstand. We suggest that sea level, which may be responding to some volcano-tectonic event, is the common link and ultimately the driving force for orgC deposition in globally distributed basins under different climatic and ocean circulation regimes. The rate of production of warm, saline deep water may have been proportional to the area of shelf flooding such that the maximum occurred near the Cenomanian-Turonian boundary. As rates of deep-water formation increased, rates of upwelling of deeper oceanic water masses must also have increased thereby increasing sea-surface fertility and productivity. In somewhat restricted higher latitude basins, such as the Cretaceous Interior Seaway of North America, periodic high rates of freshwater runoff coupled with deepening seas during the transgression created periodic salinity stratification, oxygen depletion in bottom waters, and resultant enhanced orgC preservation. The disappearance of some types of keeled planktonic formainifers and ammonites at the Cenomanian-Turonian boundary is probably due to the rather sudden but short-term disappearance of suitable shallow midwater habitats because of widespread severe oxygen depletion in these levels. This interpretation is strengthened by the occurrence of benthic-free zones or depauperate benthic faunas near the Cenomanian-Turonian boundary in many localities.
Interannual variations of tropical cyclone activity over the north Indian Ocean

An examination of the interannual variations of tropical cyclone (TC) activity over the North Indian Ocean during 1983–2008 has been carried out. The results suggest that instead of local sea surface temperatures, such variations, at least over the Bay of Bengal (BB) during October‐November‐December (OND), can be attributed to similar variations in the atmospheric flow patterns and moist static energy that are apparently forced largely by the El Niño/Southern Oscillation (ENSO). In an El Niño year, conditions for TC genesis and development, including 850‐hPa relative vorticity, 200–850‐hPa vertical shear of zonal wind, moist static energy, 500‐hPa zonal wind, 500‐hPa and 850‐hPa geopotential height and 200‐hPa divergence, are generally less favourable in BB and fewer intense cyclones are observed during OND. The reverse occurs during a La Niña event. However, causes of the variability of TC activity over BB during April‐May‐June and that over Arabian Sea have yet to be found, which may be due to the small sample size. Copyright © 2011 Royal Meteorological Society
Vertical seismic profiling

In vertical seismic profiling (VSP), VSP seismic data is transformed into surface seismic data by mapping segments of the VSP seismic data into surface seismic data time. The transformation results in data which is more easily interpreted with respect to determining subsurface structure because the data is stacked and because the data is in a more conventional form.
Genotype by Environment Interaction (G x E) and Grain Yield Stability Analysis of Ethiopian Linseed and Niger Seed Varieties

General Background : Niger seed [( Guizotia abyssinica (L.F.) Cass. ), 2n = 30] and Linseed [( Linum usitatissimum L.), n=15] are indigenous oil crops of Ethiopia. Over many years, there are a few Linseed and Niger seed varieties developed and released through intensive breeding and genetics research program in Ethiopia. However, whether these varieties are stable, adaptable to the environments of Western Ethiopia and similar agro-ecologies are not clear. Objectives: The objectives of the study were to (i) assess genotype by environment interaction (G x E) and (ii) identify stable and adaptable Linseed and Niger seed varieties for specific and wide adaptions. Materials and methods : All Niger seed and Linseed released varieties of Ethiopia between the years 1984 and 2008 were tested for multi-locations and years. Independent experiments of linseed and Niger seed varieties were evaluated in Randomized Complete Block Design replicated three times. Eight varieties of Linseed with one local variety were evaluated at Arjo, Gute and Shambu locations. In addition, five Niger seed varieties including one local variety were tested at Bako, Gute and Shambu locations. Summary of the result and application of the findings: The seed yields ranged between 0.898 tons ha-1 and 1.575 tons/ha for Linseed and between 0.600 tons ha-1 and 0.690 tons ha-1 for Niger seed. Analysis of variance using additive main effects and multiplicative interactions (AMMI) model revealed significant differences (pG0.01) for genotype, environment, genotype x environment interaction and interaction principal component (IPCA1) for Linseed, while only environment was found to be significantly different for Niger seed. Based on AMMI analysis, Kulumsa-1 was the best yielding, stable and widely adapted, while CI-1525 and Berene were high yielding but unstable and specifically adapted Linseed varieties to high yielding environments. Belay 96, Chilalo, Tole and CI-1652 were moderately stable and adapted to high yielding environments. Among Niger seed varieties, Shambu-1 and Esete-1 had comparable seed yield with moderately stable for the tested environments whereas Kuyu and local variety were unstable and not adopted to the testing environments. Key words/phrases: Adapted variety, Additive main effect and multiplicative interaction (AMMI), Genotype x environment (G x E) interaction, Stable variety
Comparison of Temperature-Time Threshold-and ET-based Irrigation Scheduling for Corn Production

Techniques using crop canopy temperature measurements to minimize or manage plant water stress have the potential of providing automated irrigation scheduling without resorting to traditional soil water measurement-based or weather-based water budget scheduling. A relatively new canopy temperature technique developed by the USDA-ARS and patented under the name BIOTIC uses a Temperature-Time Threshold (TTT) to schedule irrigation. The TTT method accumulates time that a crop canopy is above a specified temperature. When the accumulated time exceeds the specified TTT value an irrigation event signal is generated. Three corn irrigation scheduling treatments using TTT values of 2.5, 4.0 or 5.5 h above a canopy temperature of 28 C were compared to 100% and 65% of calculated ETc and to a treatment receiving no further irrigation after mid-July at Colby, Kansas. The results indicate that a TTT treatment using a threshold of 2.5 h corresponds reasonably well to a 100% ETc replacement treatment. Results also indicate that the measured TTT values were more closely related to the prevailing weather conditions than to irrigation level or plant available soil water.
Characterization and reducibility of Itakpe and Agbaja (Nigerian) iron ores

Abstract Two iron ore samples from Nigeria have been examined using TG, DTA, EGA, XRD, and optical and electron microscopy. Itakpe iron ore is hematite-rich, this mineral being intergrown with magnetite, and silica is the major impurity. Agbaja ore is an acidic oölite ore consisting of goethite and magnetite, with alumina, silica and phosphorus as major impurities. Itakpe is typical of a rich ore formed by magmatic segregation whilst Agbaja is a lean ore of sedimentary origin. Isothermal mass-change measurements in hydrogen and carbon monoxide in the range 800–1100°C show Agbaja to be less reducible than Itakpe; in particular, Agbaja is very irreducible at 1100°C because of sintering of the ore. Characterization and reducibility experiments were also carried out on Corby (Northamptonshire, UK) iron ore for comparison.
Contribution of research borehole data to modelling fine-grained turbidite reservoir analogues, Permian Tanqua–Karoo basin-floor fans (South Africa)

Outcrop analogue studies can be augmented and constrained by drilling research wells through the same stratigraphic interval. Close-to-outcrop wells help to validate outcrop observations with well log and core data and thus improve the use of such data in actual field developments. Research wells located further away from the outcrops increase the spatial data coverage and can give important insight into regional facies distributions and net:gross changes. In the Tanqua–Karoo Basin (South Africa), seven wells were drilled into fine-grained sand-rich basin-floor fans and interfan mudstones to supplement outcrop data. Three close-to-outcrop wells proved useful in establishing characteristic log responses of the main architectural elements identified from the nearby outcrops. Lithofacies were correctly identified in more than 80% of cases using an artificial neural network. Borehole images provided detailed information on sedimentary structures, including a wealth of palaeocurrent data from climbing ripples that significantly enhanced the interpretations based only on outcrops. Wells sited away from the outcrops supplied information on lateral thickness and facies trends and intrafan stacking patterns, which helped to define the stratigraphic evolution of the fans. The combined data indicate that deposition was controlled in part by subtle basin-floor topography, and that intrafan lobe switching took place, leading to internal subdivisions that potentially caused effective compartmentalization of the basin-floor fan.