Miracle-dz/UniFAR-FTUs huggingface dataset:
A modeling study of the time-averaged electric currents in the vicinity of isolated thunderstorms

A thorough examination of the results of a time-dependent computer model of a dipole thunderstorm revealed that there are numerous similarities between the time-averaged electrical properties and the steady state properties of an active thunderstorm. Thus, the electrical behavior of the atmosphere in the vicinity of a thunderstorm be can be determined with a formulation similar to what was first described by Holzer and Saxon in 1952. From the Maxwell continuity equation of electric current, a simple analytical equation was derived that expresses a thunderstorm's average current contribution to the global electric circuit in terms of the generator current within the thundercloud, the intracloud lightning current, the cloud-to-ground lightning current, the altitudes of the charge centers, and the conductivity profile of the atmosphere. This equation was found to be nearly as accurate as the more computationally expensive numerical model, even when it is applied to a thunderstorm with a reduced conductivity thundercloud, a time-varying generator current, a varying flash rate, and a changing lightning mix.
Estimating structural properties of riparian forests with airborne lidar data

Riparian forest zones adjacent to surface water such as streams, lakes, reservoirs and wetlands maintain significant forest ecosystem functions including nutrient cycling, vegetative communities, water quality, fish and wildlife habitat and landscape aesthetics. In order to support the sustainable management of riparian forests, riparian zones should first be carefully delineated and then structural properties of riparian vegetation, especially forest trees, should be accurately measured. Geographical information system (GIS) techniques have been previously implemented to determine riparian zones quickly and reliably. However, basic measurements of forest structures in riparian areas have relied heavily on field-based surveys, which can be extremely time consuming in large areas. In this study, riparian forest zones were initially located using GIS techniques and then airborne lidar (light detection and ranging) data were used to determine and analyse structural properties (i.e. tree height, crown diameter, canopy closure and vegetation density) of a sample riparian forest. Lidar-derived tree height and crown diameter measurements of sample trees were compared with field-based measurements. Results indicated that 77.92% of the riparian area in the study area was covered by forest. Based on lidar-derived data, the average tree height, total crown width, canopy closure (above 3 m) and vegetation density (3–15 m) were found to be 74.72 m, 16.82 m, 71.15% and 26.05%, respectively. Although we found differences between measurement methods, lidar-derived riparian tree measurements were highly correlated with field measurements for tree height (R 2 = 88%) and crown width (R 2 = 92%). Differences between measurement methods were likely a result of difficulties associated with field measurements in the dense vegetation that is often associated with forested riparian areas.
Aerosol forcing, climate response and climate sensitivity in the Hadley Centre climate model

[1] An atmosphere/mixed-layer-ocean climate model is used to investigate the climate responses to forcing by 1860–2000 changes in anthropogenic sulfate, biomass-burning and black carbon aerosols, and how they compare with the effect of doubling CO2. While the patterns of temperature response from sulfate and black carbon aerosols are similar and reveal high sensitivity at high latitudes in the northern hemisphere, they are significantly different to that due to CO2 which shows high latitude sensitivity in both hemispheres, and to biomass-burning aerosols which shows a much more uniform temperature response. Climate sensitivity, the response of natural primary aerosols, and the degree to which forcings and responses are additive, are also investigated. The sum of the separate temperature and precipitation responses to each aerosol is found to be remarkably similar to that obtained if all aerosols are changed simultaneously.
The Great Barrier Reef: a 700 000 year diagenetic history

A deep borehole through Ribbon Reef 5 in the Great Barrier Reef off north‐eastern Australia has identified a variety of cements, including epitaxial, radial prismatic and spherular aragonite, together with blocky, prismatic and fibrous calcite. These cements are discontinuously arranged within the sequence that consists predominantly of grainstones but locally includes clotted muddy and filamentous textures that may be of microbial origin. Calcite cements vary in morphology with groups of crystals that include acute scalenohedral, rhombohedral and flattened concordant terminations; these show varying densities of inclusions that locally define growth zones and in some terminations divide in the manner of ‘split crystals’ to form fibrous fringes. Morphological changes in calcite are inferred to reflect changes in water chemistry and crystal growth rates at the time of growth, allied to their relationship to the palaeo‐water table, and linked in turn to changes in sea‐level. Neomorphism and dissolution are widespread and variations in the severity of both imply response to the degree of undersaturation of pore waters that at times were probably balanced within very narrow limits. A total of 10 depositional units are identified. Those units at the base of the borehole reflect deposition and diagenesis within a marine environment. The influence of meteoric waters, indicated by stable isotopes, is first apparent at the top of Unit 1 and in Unit 2 (184 to 155 m below sea floor). Petrographic evidence of vadose conditions appears at the tops of Unit 3 (131 to 99 m below sea floor). Units 4 to 8, all deposited under marine conditions, provide isotopic evidence of meteoric or mixing‐zone waters and petrographic indicators of vadose conditions, typically at the top of the units. Evidence indicates that in Unit 5 the water table was mobile and Units 6a, 6b, 7 and 8, all characterized by ultraviolet fluorescent cements, are capped by sub‐aerial erosion surfaces. Unit 9 (the Holocene) reflects the recent re‐establishment of marine conditions. The extent of alteration of the entire sequence reflects the substantial and pervasive influence of meteoric waters. This effect is interpreted as a result of a greater rainfall and river flow from the mainland during early and late stages of interstadial periods. The study reflects progress in the ability to recognize the diagenetic signal generated by sea‐level change. However, whereas the isotopic results reflect the changing relationships between vadose and phreatic zones in groundwater systems beneath successive emergent surfaces, their correspondence with petrographic features is expressed only weakly and commonly lacks the systematic sequential overprinting implied by the distribution of cathodoluminescent zones of cements in many ancient limestones.
Rapid Smothering of Coral Reef Organisms by Muddy Marine Snow

Abstract Estuarine mud, when resuspended in nutrient-rich near-shore water, aggregates to marine snow, and within minutes to hours can exert detrimental or even lethal effects on small coral reef organisms. In a pilot study, estuarine mud was suspended in near-shore and off-shore waters of the Great Barrier Reef to a final concentration of 170 mg l−1. The short-term responses of a coral (Acropora sp.) and coral-inhabiting barnacles (subfamily Pyrgomatidae), exposed to either near-shore or off-shore water, were microscopically observed and video recorded. In the off-shore water treatment, flocculation was minor, and aggregate sizes were c. 50 μm. The organisms were able to clean themselves from these small settling aggregates at low siltation (
Compensation for subpixel roughness effects in thermal infrared images

Emissivity spectra recovered from spectral radiance images may have lowered spectral contrast due to irradiance from nearby surface elements (‘cavity effect’). For analysis based only on photointerpretation or Reststrahlen band identification, it is not always necessary to account for cavity effects, but for full spectral analysis it may be desirable. We present an approach to compensate thermal infrared (TIR) images for cavity radiation. This approach is based on optical estimates of subpixel surface roughness and estimation of cavity contribution for different natural surfaces using a TIR radiosity model. It was tested using tripod-mounted Hyper-Cam (Telops, Inc., Quebec City, Canada) hyperspectral TIR images of natural targets from the Mojave Desert, California, USA, along with centimetre-scale digital elevation models of similar targets measured by ground lidar. For remote subpixel roughness estimation, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) nadir- and aft-looking (27.6°) near-infrared (NIR) brightness ratios, as well as synthetic aperture radar (SAR) images calibrated to roughness root mean square (RMS), were used. The TIR compensation approach is adaptable for different spectral resolutions, including hyperspectral.
Organic matter dynamics and carbon sequestration rates for a tillage chronosequence in a Brazilian Oxisol

Amounts and rates of C sequestration under no-tillage are not known for a major ecological region of south Brazil. These were assessed in a Brazilian Oxisol under a plow and no-tillage chronosequence located in Parana State. The chronosequence consisted of six treatments: (i) native field (NF); (ii) 1-yr plow conversion of native field to cropland (PNF-1); (iii) no-tillage for 10 yr (NT-10); (iv) no-tillage for 20 yr (NT-20); (v) no-tillage for 22 yr (NT-22); and (vi) conventional tillage for 22 yr (CT-22). Soil samples were collected from five depths. No-tillage, compared with the NF treatment, caused a significant increase in soil organic C (SOC) storage. More than 60% of this increase occurred in the 0- to 10-cm soil layer. There was a decrease in the amount of SOC in the CT-22 compared with the NF soil treatment and 97% of this loss also occurred in the 0- to 10-cm layer. There was a close relationship between the SOC content and the amount of crop residues input (R 2 = 0.74, P ≤ 0.05). There were increased SOC concentrations in the finer particle-size fractions ( 20 μm) than in the finer (<20 μm) particle-size fractions. The C sequestration rate for no-tillage was 80.6 g C m -2 yr -1 for the 0- to 20-cm depth and 99.4 g C m -2 yr -1 for the 0- to 40-cm depth. The no-tillage C sequestration potential for South Brazil was estimated as 9.37 Tg C yr -1 .
Chemical, Mineralogical, and Physical Property Differences Between Moderately and Severely Eroded Illinois Soils

The effects of degree of erosion on the chemical, mineralogical, and physical properties of seven Illinois soils were evaluated. At each site, separate map units of moderately and severely eroded phases of a soil series were located in the same field. (.) Soil descriptions were made from pits located within each eroded phase of all seven soil series. Soil samples were taken with depth to measure the chemical, mineralogical, and physical properties of each phase of all soil series.
Mystery of the volcanic mass‐independent sulfur isotope fractionation signature in the Antarctic ice core

We simulate the record of sulfur mass‐independent fractionation (MIF) in sulfates found in the Antarctic ice cores from the 1991 eruption of Mt. Pinatubo. Discovery of MIF in sulfur isotopes in Archean/Early Proterozoic sediments and lack of MIF in sulfur in younger rocks placed a strict upper limit on the amount of oxidants and oxygen in the ancient Earth's atmosphere prior to 2.3 Gyr ago. However, recent measurements in ice cores suggest that some non‐zero MIF in sulfate can be delivered to Antarctica following large volcanic eruptions. Current photochemical experiments do not identify the specific reaction responsible for sulfur MIF production. Here we show that a time‐dependent non‐zero sulfur MIF can be delivered to the ground in the present atmosphere if the MIF–producing process is SO3 photolysis. Fractionation from such photolysis has not been considered before, but is consistent with the available experimental data.
Effect of Weight and Draught on the Performance of Disc Plough on Sandy-loam Soil

In this research, the relationship between depth of cut, increase in weight of disc plough as well as the draught has been investigated using dimensional analysis on a sandy loam soil. The experiment was conducted on a site with three different moisture contents level at five different speeds (0.83, 1.39, 1.94, 2.5 and 2.78 ms^(-1)). It was observed that the depth of penetration increase with an increase in draught and increase in soil moisture content. From the site, the depth of cut was minimum at 4.9% and maximum at 9.4% moisture content. The result obtained from the validation shows that the model can be used effectively to determine the depth of cut in sandy loam soil and also the draught-speed relationship obtained from this work can be used to predict the power requirement of the disc plough in other soil types. The draught increase linearly with the depth of cut as predicted from the model. The result of the soil properties after tillage showed increase with shear strength, bulk density and depth.
Determination of the drag coefficients of emergent and just submerged willows

This paper presents results regarding the flow resistance and the drag coefficient of floodplain vegetation. According to the literature review, most of the investigations concerning the interaction between flow and woody vegetation are based on laboratory experiments where the vegetation is idealized with a high level of abstraction. However, the vegetation's resistance behaviour depends on many natural parameters, such as the flexural rigidity, the manner of contraction in the current, the degree of foliation and the vibration behaviour. Furthermore the varying shape of the vegetation elements due to the current forces has to be observed. The drag coefficients of three kinds of willow species depending on the flow conditions and the effect of the plants flexibility and foliation on the projected plant area and thus on the drag coefficient are presented in this paper. The results show that it is very important to distinguish between leafy and leafless condition as the drag coefficient is a result of different physical effects.
Paleomagnetic correlation of Late Quaternary lava flows in the lower east rift zone of Kilauea Volcano, Hawaii

Paleomagnetic data reflecting paleosecular variation (PSV) of the geomagnetic field are used to correlate individual lava flows in the lower east rift zone of Kilauea Volcano. This area has been recently mapped based on petrography, stratigraphy, soil development, and degree of weathering of the flows; eight 14C dates also provide a framework for the relative age assignments. Site-mean directions of remanent magnetization for historic flows in this region indicate that local magnetic anomalies do not mask the PSV signal, that within-flow angular differences are generally <5°, and that temporal resolution of the paleomagnetic directions is of the order of 100 years. The paleomagnetic correlations do not conflict with the observed stratigraphic relationships, and PSV reference curves from dated lava flows and lake sediments have also been used to help determine the sequence of directional groups. Paleomagnetic grouping of flows into eruptive events indicates a different and perhaps more refined eruptive history for the lower east rift zone than implied by the geologic mapping alone. The number of individual flows based on petrographic distinctions is likely the same, but the frequency of events (including petrographically distinct flows) is apparently lower than previously thought. Flows from ridge crest vents bifurcated by the rift indicate formation of the central graben in this region after ∼300 years ago, possibly related to the 1790 eruptions along dual fractures.
Palaeoenvironmental record of glacial lake evolution during the early Holocene at Sokli, NE Finland

The development of a glacial lake impounded along the retreating, northeastern ice margin of the Fennoscandian Ice Sheet during the last deglaciation and environmental conditions directly following the early Holocene deglaciation have been studied in NE Finland. This so‐called Sokli Ice Lake has been reconstructed previously using topographic and geomorphologic evidence. In this paper a multiproxy approach is employed to study a 3‐m‐thick sediment succession consisting of laminated silts grading into gyttja cored in Lake Loitsana, a remnant of the Sokli Ice Lake. Variations in the sediment and siliceous microfossil records indicate distinct changes in water depth and lake size in the Loitsana basin as the Sokli Ice Lake was drained through various spillways opening up along the retreating ice front. Geochemical data (XRF core‐scanning) show changes in the influence of regional catchment geochemistry (Precambrian crystalline rocks) in the glacial lake drainage area versus local catchment geochemistry (Sokli Carbonatite Massif) within the Lake Loitsana drainage area during the lake evolution. Principal component analysis on the geochemical data further suggests that grain‐size is an additional factor responsible for the variability of the sediment geochemistry record. The trophic state of the lake changed drastically as a result of morphometric eutrophication once the glacial lake developed into Lake Loitsana. The AMS radiocarbon dating on tree birch seeds found in the glaciolacustrine sediment indicates that Lake Loitsana was deglaciated sometime prior to 10 700 cal. a BP showing that tree Betula was present on the deglaciated land surrounding the glacial lake. Although glacial lakes covered large areas of northern Finland during the last deglaciation, only few glaciolacustrine sediment successions have been studied in any detail. Our study shows the potential of these sediments for multiproxy analysis and contributes to the reconstruction of environmental conditions in NE Finland directly following deglaciation in the early Holocene.
Thermal fluctuation analysis: A new technique in rock magnetism

Thermal fluctuation analysis is a new method of determining ‘magnetic grain size’ v and microscopic coercive force HK in particles too small for direct domain observations. When it is used with single-domain particles, thermal fluctuation analysis is a method of magnetic granulometry, since v is the physical grain volume and HK is usually closely related to grain shape. For multidomain particles, v corresponds to one Barkhausen jump of a domain wall, and HK describes the opposition to wall motion. The technique requires three steps: (1) measurement of coercive force Hc and saturation magnetization over a broad temperature range, (2) separation of the contributions of HK and the ‘fluctuation field’ Hq to HC, in a manner suggested by the Neel (1949) theory, and (3) calculation of average values of v and room temperature HK from Hq(T) and HK(T). Thermal fluctuation analysis is the only simple means of calculating average v; and HK separately. If thermal fluctuations are important, as is always the case for the fine particles or small wall displacements involved in low-field thermoremanence or viscous remanence, thermal and alternating field demagnetization do not resolve v and HK unambiguously, because observed coercivities and blocking temperatures TB depend on both v and HK. The method is tested by applying it to single-domain materials of known grain size. Fluctuation analysis is then used to infer the possible domain structure of 500- to 2200-A magnetite particles and to point up a deficiency in the Stacey and Banerjee (1974) procedure for detecting ordering of lattice defects impeding domain wall motion. Potential broader applications include determining mean grain sizes of single, and under favorable conditions, double populations of magnetic carriers in rocks, defining average elongation for single-domain particles in rocks and synthetic dispersions (e.g., magnetic recording tapes), and deducing the mechanism of anisotropy (shape, crystalline or magnetoelastic) or of opposition to wall motion (strain, inclusion or magnetostatic). The main limitations to the method are that the averages of v and HK become nonstationary if Hc measurements are made within the TB range and that step 2 (separation of HK(T) and Hq(T)) is difficult unless HK is predominantly due to a single anisotropy or wall opposition mechanism.
Microbial keratitis in Sao Paulo, Brazil: a 10-year review of laboratory results, epidemiological features, and risk factors.

PURPOSE To study epidemiological data, laboratory results, and risk factors associated with microbial keratitis. METHODS We conducted a retrospective study of corneal sample cultures from patients with microbial keratitis from January 2010 to December 2019. Results were analyzed according to the etiological diagnosis of bacterial, mycotic, or parasitic infection and were associated with related risk factors. RESULTS We analyzed 4810 corneal samples from 4047 patients (mean age 47.79 ± 20.68 years; male 53.27%). The prevalence of bacterial, fungal, and Acanthamoeba infections were 69.80%, 7.31%, and 3.51%, respectively. The most frequently isolated bacteria were coagulase-negative Staphylococcus (CoNS) (45.14%), S. aureus (10.02%), Pseudomonas spp. (8.80%), and Corynebacterium spp. (6.21%). Among CoNS, the main agent was S. epidermidis (n=665). For mycotic keratitis, Fusarium spp. (35.42%) and Candida parapsilosis (16.07%) were the most common agents among filamentous and yeasts isolates, respectively. Contact lens use was associated with a positive culture for Acanthamoeba spp. (OR = 19.04; p < 0.001) and Pseudomonas spp. (OR = 3.20; p < 0.001). Previous ocular trauma was associated with positive fungal cultures (OR = 1.80; p = 0.007), while older age was associated with positive bacterial culture (OR = 1.76; p = 0.001). CONCLUSIONS Our findings demonstrated a higher positivity of corneal sample cultures for bacteria. Among those, CoNS was the most frequently identified, with S. epidermidis as the main agent. In fungal keratitis, Fusarium spp. was the most commonly isolated. Contact lens wearers had higher risks of positive cultures for Acanthamoeba spp. and Pseudomonas spp. Ocular trauma increased the risk of fungal infection, while older age increased the risk of bacterial infection.
Climatic atlas of Texas

Climate is the history of weather and is defined by the long-term averages of atmospheric variables such as precipitation, temperature, evaporation and wind. This atlas identifies "average" conditions of these four major components of climate through a series of maps and wind roses. The maps depict the statewide distribution of monthly and annual values of average precipitation. average temperature. and average gross lake surface evaporation rates. Wind roses show the frequency of occurrence of average wind direction and speed in selected cities across the State.