Miracle-dz/UniFAR-FTUs huggingface dataset:
RIVERBANK STABILITY ANALYSIS. I: THEORY

In this paper, a slope stability analysis for steep banks is used in conjunction with a method to calculate lateral erosion distance, to predict bank stability response to lateral erosion or bed degradation. The failure plane angle, failure block width, and volume of failed material per unit channel length may be calculated for the critical case. These parameters define the bank geometry following failure and form the starting point for subsequent analyses. The calculation procedure is illustrated by a worked example. Following mass failure slump, debris accumulates at the bank toe. The debris is removed by lateral erosion prior to further oversteepening or degradation generating further mass failures. Any process‐based model for channel width adjustment must account for the combined effects of lateral erosion and mass instability in producing bank instability. The approach adopted here represents a marked improvement over earlier work, which does not account for changes in bank geometry due to lateral er.
On the HO2 + HO2 reaction: Its misapplication in atmospheric chemistry models

The self-reaction of the HO2 radical is an important termination reaction for HOχ and it is the major gas phase source of hydrogen peroxide in the atmosphere. It is well established that the rate of this reaction is sensitive to both pressure and water vapor concentrations. The NASA recommended rate parameter (DeMore et al., 1992) has been utilized in several detailed gas phase chemical mechanisms for modeling the troposphere, but several other recent studies have omitted one or both of the terms for the rate constant. If both the pressure and the water dependent terms are omitted the relative error can be as high as 75% at the surface to near 30% at 10 km for water vapor saturated conditions. Models which omit these terms will predict incorrect HOχ budgets, underestimate gas phase hydrogen peroxide formation rates, and overestimate ozone and organic peroxide formation rates especially in clouds or under marine conditions.
Measuring the Electrical Properties of Soil Using a Calibrated Ground‐Coupled GPR System

Traditional methods for estimating vadose zone soil properties using ground penetrating radar (GPR) include measuring travel time, fitting diffraction hyperbolae, and other methods exploiting geometry. Additional processing techniques for estimating soil properties are possible with properly calibrated GPR systems. Such calibration using ground‐coupled antennas must account for the effects of the shallow soil on the antenna's response, because changing soil properties result in a changing antenna response. A prototype GPR system using ground‐coupled antennas was calibrated using laboratory measurements and numerical simulations of the GPR components. Two methods for estimating subsurface properties that utilize the calibrated response were developed. First, a new nonlinear inversion algorithm to estimate shallow soil properties under ground‐coupled antennas was evaluated. Tests with synthetic data showed that the inversion algorithm is well behaved across the allowed range of soil properties. A preliminary field test gave encouraging results, with estimated soil property uncertainties (±σ) of ±1.9 and ±4.4 mS/m for the relative dielectric permittivity and the electrical conductivity, respectively. Next, a deconvolution method for estimating the properties of subsurface reflectors with known shapes (e.g., pipes or planar interfaces) was developed. This method uses scattering matrices to account for the response of subsurface reflectors. The deconvolution method was evaluated for use with noisy data using synthetic data. Results indicate that the deconvolution method requires reflected waves with a signal/noise ratio of about 10:1 or greater. When applied to field data with a signal/noise ratio of 2:1, the method was able to estimate the reflection coefficient and relative permittivity, but the large uncertainty in this estimate precluded inversion for conductivity.
Diversity and phylogeny of Baltic Sea picocyanobacteria inferred from their ITS and phycobiliprotein operons

Picocyanobacteria of the genus Synechococcus span a range of different colours, from red strains rich in phycoerythrin (PE) to green strains rich in phycocyanin (PC). Here, we show that coexistence of red and green picocyanobacteria in the Baltic Sea is widespread. The diversity and phylogeny of red and green picocyanobacteria was analysed using three different genes: 16S rRNA-ITS, the cpeBA operon of the red PE pigment, and the cpcBA operon of the green PC pigment. Sequencing of 209 clones showed that Baltic Sea picocyanobacteria exhibit high levels of microdiversity. The partial nucleotide sequences of the cpcBA and cpeBA operons from the clone libraries of the Baltic Sea revealed two distinct phylogenetic clades: one clade containing mainly sequences from cultured PC-rich picocyanobacteria, while the other contains only sequences from cultivated PE-rich strains. A third clade of phycourobilin (PUB) containing strains of PE-rich Synechococcus spp. did not contain sequences from the Baltic Sea clone libraries. These findings differ from previously published phylogenies based on 16S rRNA gene analysis. Our data suggest that, in terms of their pigmentation, Synechococcus spp. represent three different lineages occupying different ecological niches in the underwater light spectrum. Strains from different lineages can coexist in light environments that overlap with their light absorption spectra.
Two billion year old isotopically heavy carbon: evidence from the Labrador Trough, Canada

Forty-eight samples of bulk carbonates were studied from the Dunphy, Portage, Alder, Uve, Denault, and Abner formations and the undivided Pistolet subgroup in the Labrador Trough, Quebec, Canada. The carbonate units occur as a number of thick beds (up to 300 m) within 100–600 m thick formations. They are interbedded with siliciclastic sediments and are composed of crystalline, sparry, micritic allochemical and stromatolitic dolostones. The carbonate rocks are recrystallized and metamorphosed (up to amphibolite grade). They are chemically dolostones, and include chemical or biochemical laminated and massive dolostones, dolorudites, dolarenites, and dololitites, which were deposited in shallow-water (Dunphy, Denault, and Abner formations) to relatively deep water (Uve Formation) marine environments. Reef facies are present in the Denault and Abner formations. The Dunphy, Portage, Alder, and Uve formations, deposited between 2.17 and 2.14 Ga, yield isotopically heavy values of δ13C(PDB) ranging from + 5.3 to.
Assessment of crustal velocity models using seismic refraction and reflection tomography

Two tomographic methods for assessing velocity models obtained from wide-angle seismic traveltime data are presented through four case studies. The modelling/inversion of wide-angle traveltimes usually involves some aspects that are quite subjective. For example: (1) identifying and including later phases that are often difficult to pick within the seismic coda, (2) assigning specific layers to arrivals, (3) incorporating pre-conceived structure not specifically required by the data and (4) selecting a model parametrization. These steps are applied to maximize model constraint and minimize model non-uniqueness. However, these steps may cause the overall approach to appear ad hoc, and thereby diminish the credibility of the final model. The effect of these subjective choices can largely be addressed by estimating the minimum model structure required by the least subjective portion of the wide-angle data set: the first-arrival times. For data sets with Moho reflections, the tomographic velocity model can be used to invert the PmP times for a minimum-structure Moho. In this way, crustal velocity and Moho models can be obtained that require the least amount of subjective input, and the model structure that is required by the wide-angle data with a high degree of certainty can be differentiated from structure that is merely consistent with the data. The tomographic models are not intended to supersede the preferred models, since the latter model is typically better resolved and more interpretable. This form of tomographic assessment is intended to lend credibility to model features common to the tomographic and preferred models. Four case studies are presented in which a preferred model was derived using one or more of the subjective steps described above. This was followed by conventional first-arrival and reflection traveltime tomography using a finely gridded model parametrization to derive smooth, minimum-structure models. The case studies are from the SE Canadian Cordillera across the Rocky Mountain Trench, central India across the Narmada-Son lineament, the Iberia margin across the Galicia Bank, and the central Chilean margin across the Valparaiso Basin and a subducting seamount. These case studies span the range of modern wide-angle experiments and data sets in terms of shot‐receiver spacing, marine and land acquisition, lateral heterogeneity of the study area, and availability of wide-angle reflections and coincident near-vertical reflection data. The results are surprising given the amount of structure in the smooth, tomographically derived models that is consistent with the more subjectively derived models. The results show that exploiting the complementary nature of the subjective and tomographic approaches is an effective strategy for the analysis of wide-angle traveltime data.
Parlamentares, representação política e redes sociais digitais: perfis de uso do Twitter na Câmara dos Deputados

The article reflects on how members of the Brazilian House of Representatives use Twitter as part of their political communications strategy. We examine all the 463 official accounts registered on Twitter in order to understand the factors that lead legislators to invest in microblogging. Such accounts were weekly monitored (between February and July 2012) by using the statistical software "R". The results points out correlations between the use of Twitter and attributes like age and occupation of leadership positions.
Upper mantle structure of the Kaapvaal craton from surface wave analysis—a second look

Surface waves from earthquakes recorded during the two‐year Southern Africa Seismic Experiment have been used to estimate the average velocity structure beneath the Kaapvaal craton. By cross‐correlating the data with synthetics derived using mode summation techniques, I measure frequency‐dependent phase delays for Love and Rayleigh waves, as well as higher modes, for 12 events ranging in epicentral distance between 12° and 91°. I simultaneously invert the traveltime delays for structure beneath the array and outside of the array. In this way, heterogeneity along the path lying outside of the array is not mapped erroneously into structure beneath the array. The differential dispersion between the Love and Rayleigh waves require some anisotropy in the upper mantle; however, models with a range of anisotropic depths (as shallow as 150 km and as deep as 220 km) can equally well fit the data. The sensitivity of the fundamental mode surface waves used in this study begins to decline significantly below ∼200 km depth limiting interpretation of deeper structure. Nonetheless, this range of anisotropic depths is significantly different than the 100 km depth proposed in a recent study by Freybourger et al. [2001] using a similar technique and different data from the same array. I attribute the difference in their dispersion measurements and modeling to the improper use of a phaseless (i.e. frequency‐dependent) filter on the data, which systematically biased their measurements at lower frequencies. In addition, I find no evidence of a low‐velocity layer as proposed by Qui et al. [1996] and Priestley [1996].
SUSCEPTIBILITY OF SOILS TO PREFERENTIAL FLOW OF WATER : A FIELD STUDY

Flow pathways of water and solutes in soils form distinct patterns, which are not a priori predictable. Macropore structure is a prime cause, but other factors, such as differing initial or boundary conditions, may also predispose a soil to produce bypassing of infiltrating water. This study was conducted to assess the flow pathways of water in different soils and to investigate the effect of initial water content on the flow pattern. Dye-tracing experiments were carried out at 14 different field sites. The sites represent a good portion of soils used for agricultural crop production in Switzerland. Each site consisted of two 1.4 by 1.4 m plots, one of which had been covered with a plastic roof for two months before the experiment to achieve different initial water contents. Forty millimeters of water containing the dye Brilliant Blue FCF (C.I. Food Blue 2) were applied within 8 hours onto the plots with a sprinkling apparatus. One day after irrigation the plots were excavated, and the stained pattern was examined on a vertical 1 by l m soil profile. The spatial structure of flow patterns showed remarkable differences. In most soils, water bypassed the soil matrix. In some soils, dye penetrated beyond l m depth, whereas in others it remained in the top 50 cm. Structured soils were more prone to produce bypass flow, deep dye penetration, and pulse splitting than nonstructured soils. The initial water content had a less pronounced effect in some soils and no effect in others.
Shear Strength and Pore-Water Pressure Characteristics during Constant Water Content Triaxial Tests

Shear strength parameters used in geotechnical design are obtained mainly from the consolidated drained (CD) or consolidated undrained (CU) triaxial tests. However in many field situations, soils are compacted for construction purposes and may not follow the stress paths in CD or CU triaxial tests. In these cases, the excess pore-air pressure during compaction will dissipate instantaneously, but the excess pore-water pressure will dissipate with time. Under this condition, it can be considered that the air phase is drained and the water phase is undrained. This condition can be simulated in a constant water content (CW) triaxial test. The purpose of this paper is to present the characteristics of the shear strength, volume change, and pore-water pressure of a compacted silt during shearing under the constant water content condition. A series of CW triaxial tests was carried out on statically compacted silt specimens. The experimental results showed that initial matric suction and net confining stress play an important role in affecting the characteristics of the shear strength, pore-water pressure, and volume change of a compacted soil during shearing under the constant water content condition. The failure envelope of the compacted silt exhibited nonlinearity with respect to matric suction.
Assessing hurricane‐induced tree mortality in U.S. Gulf Coast forest ecosystems

[1] Tropical cyclones disturb forest ecosystems and have the potential to alter forest structure and species composition as well as ecosystem functions including rates of nutrient cycling and biomass accumulation. Quantifying these forest disturbances is necessary to evaluate the extent and severity of damage for estimating biomass loss, developing regional carbon budgets, and making management decisions following hurricanes. In this study, we quantified forest disturbance (downed and dead and snapped trees) produced by hurricanes using a relationship between field-measured tree mortality and Landsat data that can be broadly applied to Gulf Coast forest ecosystems impacted by hurricanes. Field-measured tree mortality data was collected in Gulf Coast forests at 60 inventory plots established to monitor forest disturbance produced by hurricanes Katrina and Rita, which hit the region in 2005, and Hurricane Gustav, which hit the region in 2008. Large-scale disturbance estimates were obtained by regressing Landsat and Moderate Resolution Imaging Spectroradiometer (MODIS) data that in turn were associated with Forest Inventory and Analysis (FIA) data from the U.S. Forest Service. The use of the general relationship produced a biomass loss from dead trees of 43.9 ± 8.4 Tg C for Hurricane Katrina and 37.9 ± 6.4 Tg C for Hurricane Rita, which are near the upper limit of the expected values reported in our previous studies across a number of different forest types. Our results provide an important contribution for reliable assessments of large-scale disturbance produced by hurricanes in forest ecosystems. Improving our ability to accurately assess the impacts of hurricanes on forests and on terrestrial carbon cycles is particularly important given that climate projections suggest that hurricane intensity is likely to increase.
An Early Tertiary Outcrop in North-Central Baffin Island, Northwest Territories, Canada: Environment and Significance

A thin, impure limestone was found in situ on Precambrian bedrock at latitude 70°36.6′ N and longitude 75°20′ W some 26 km northwest of the Barnes Ice Cap. The unit consists of undulating laminations composed of alternating fine- and coarse-grained sediment, which are interpreted as a series of algal mats or algal-laminated sediments. An analysis of enclosed palynomorphs indicates the presence of Ulmus, Taxodiutm, Liriodendron, Carpinus, and Engelhardtia plus other genera. On the basis of the microflora a Paleogene age is assigned to the unit. The climate at that time was warm-temperate and the environment suggested is a freshwater marsh or swamp. The outcrop is restricted to a single hill summit and its location suggests considerable Neogene geomorphological activity, primarily river-cutting associated with vertical movements along the western margin of the Davis Strait/Baffin Bay Tift.
Adaptive FEC and ARQ control for reliable high-speed UDP-based media transport

In this paper, we propose a high-speed UDP-based media transport with an adaptive error control. The proposed adaptive transport scheme controls the adaptive forward error correction (FEC) and automatic repeat request (ARQ) schemes by monitoring underlying networks so that it can effectively adapt to the fluctuation of given high-speed networks. The monitored feedbacks from the receiver enable the sender to aware of current reception status (i.e., rate/type of packet loss and packet delay). Based on this, the proposed adaptive media transport attempts to provide controlled reliability by adaptively controlling ARQ as well as adaptive FEC schemes. Experiments with high-speed network testbed have been conducted to verify the performance of the proposed transport that demonstrates the enhanced throughput at the speed of up to one Gbps.
Octahedral occupancy and the chemical composition of diagenetic (low-temperature) chlorites

Abstract The chemical composition of about 500 diagenetic chlorites, determined by electron microprobe, has been studied in six different sedimentary sequences spanning conditions from early diagenesis to low-grade metamorphism, in the temperature range 40–330°C. The range of Fe/(Fe + Mg) is almost complete and is positively correlated with Al. Five sequences show the same compositional variation. In each, the most siliceous chlorites have the lowest R2+, substantially more octahedral than tetrahedral Al, and the lowest octahedral totals. Conversely, the least siliceous have the highest R2+, nearly equal octahedral and tetrahedral Al, and octahedral totals close to that for an ideal trioctahedral mineral. A dioctahedral substitution Si[]R2−2 (where [] represents a vacant octahedral site) which decreases with temperature, describes this variation. Low octahedral totals are, however, induced by the method of calculation and need not indicate vacancies; for published wet chemical analyses of metamorphic chlorites they may simply indicate oxidation of Fe. Intergrown dioctahedral phyllosilicates may partly account for apparent vacancies in diagenetic chlorites. Nevertheless, the correlation of composition with temperature and similarities to the temperature-related evolution of synthetic chlorites, suggest that diagenetic chlorites are compositionally distinct from, but metastable with respect to, fully trioctahedral metamorphic chlorites. Temperature-related trends are modified by bulk composition, complicating their potential use for low-temperature geothermometry.
Characterization of climate and crop productivity using DSSAT for SW Uttarakhand, India

Haridwar district in south west Uttarakhand India is agriculturally very sensitive as this contributes about 35% food grain and 80% sugar to the total production of the state. Weather conditions affected production both directly and indirectly. DSSAT is a very useful tool presently available for yield forecasting taking into account the weather condition, soil condition, crop management condition and genetic coefficients. Weather data (1979–2011) was collected from the Indian Institute of Technology, Roorkee whereas the data of soil, crop management and genetic coefficients were collected conducting survey from different parts of the district. Acreage and yield data of rice, wheat and sugarcane of the district was obtained from the office of the Director Agriculture Uttarakhand for the period 2000–2011. Weather data analyzed using DSSAT recorded 1026 mm/year average annual rain with 68 rainy days/year and 65% probability of wetness/year in Haridwar. Actual average yield of rice, wheat and sugarcane was reported as 22.4 q/ha, 25.0 q/ha and 609 q/ha respectively. The DSSAT however forecasted the average yield of rice and wheat as 26.3 q/ha and 28.2 q/ha respectively. Marginally higher forecast of yield in rice and wheat over the actual through DSSAT needs further scrutiny. Regression model however responded at par with the actual forecasting the average yield in rice as 22.9 q/ha, wheat as 25.2 q/ha and sugarcane as 610 q/h. These observations confirm the scope of using DSSAT in characterising weather condition and crop yield forecasting in Uttarakhand.
Physical modelling of point-cloud (3D) and full-wave-form (4D) laser imaging

We compare results issued from a numerical model that simulates the point cloud obtained by 3D laser scanning of a scene and measurements provided by a commercial laser scanner. The model takes into account the temporal and transverse characteristics of the laser pulse, the propagation through turbulent and scattering atmosphere, the interaction with the objects of the scene (which have special optical properties: BRDF.) and the characteristics of the opto-electric detection system. The model derives 4D laser imaging information as temporal laser backscattered intensity (full wave form) is considered here. Experiments and simulations are performed on targets and scenes in order to test the performances of such imager under conditions that could be representative of future applications like Sense and Avoid, Target Recognition and Mapping,.