Miracle-dz/UniFAR-FTUs huggingface dataset:
Patterns of dissolved organic matter in subarctic peatlands

Samples of water from poor to very rich fens in the Schefferville region of subarctic Quebec revealed strong spatial and temporal variations in dissolved organic carbon (DOC), ranging from 2 to 40 mg 1−1. Concentrations of DOC tend to increase during the summer and decrease in the autumn, at most sites, which probably reflects increased plant tissue decomposition and higher rates of evapotranspiration. Principal components analysis revealed that DOC is strongly associated with Fe, NO−3-N and NO−2-N, but essentially independent of other chemical properties of the peat water, such as pH, Ca, Mg, K, P, and NH+4-N. Based on observed concentrations of DOC and estimates of summer runoff (June to September), export of DOC from four peatlands ranges from 1·1 to 4·9 gCm−2, with the lowest values for peatlands underlain by dolomite. Molecular weight fractionation of four samples revealed significant differences in the dissolved organic matter (DOM), with the largest fractions (GF/C to 10 000 nmw) being dominant in the more acid samples. The ratio of absorbance at 400 and 600 nm wavelengths (E4:E6) has been used as a simple indicator of differences in DOM type, ranging from 3 to 15. There is a strong seasonal pattern of increasing E4:E6 ratio during the summer at many sites, though this ratio is essentially independent of other chemical properties of peat waters.
Improved Advancing Front Mesh Algorithm with Pseudoislands as Internal Fronts

AbstractThis paper presents an alternative implementation of the advancing front method for generating two-dimensional triangular unstructured meshes for finite-element applications. After initializing the front along the boundaries, internal fronts, called pseudoislands, are created inside the domain where a node-spacing function condition is met. When the element creation starts, several disjoint fronts are made active, one for each pseudoisland, and the temporal order of creation of the elements follows a smaller to bigger size sequence in an inside-to-outside propagation of the front. Postprocessing routines are available for enhancing the mesh quality. A test case for an idealized geometry shows the effectiveness of the method with high node-spacing function gradients. Several discretizations of a light detection and ranging (LIDAR) derived digital elevation model are compared for demonstrating the improvement of the new advancing front version with respect to the standard version in real application.
The thermal state of permafrost in the nordic area during the international polar year 2007–2009

This paper provides a snapshot of the permafrost thermal state in the Nordic area obtained during the International Polar Year (IPY) 2007–2009. Several intensive research campaigns were undertaken within a variety of projects in the Nordic countries to obtain this snapshot. We demonstrate for Scandinavia that both lowland permafrost in palsas and peat plateaus, and large areas of permafrost in the mountains are at temperatures close to 0°C, which makes them sensitive to climatic changes. In Svalbard and northeast Greenland, and also in the highest parts of the mountains in the rest of the Nordic area, the permafrost is somewhat colder, but still only a few degrees below the freezing point. The observations presented from the network of boreholes, more than half of which were established during the IPY, provide an important baseline to assess how future predicted climatic changes may affect the permafrost thermal state in the Nordic area. Time series of active‐layer thickness and permafrost temperature conditions in the Nordic area, which are generally only 10 years in length, show generally increasing active‐layer depths and rising permafrost temperatures. Copyright © 2010 John Wiley & Sons, Ltd.
Size distribution, shape, and composition of mineral dust aerosols collected during the African Monsoon Multidisciplinary Analysis Special Observation Period 0: Dust and Biomass-Burning

[1] Dust samples were collected onboard the UK community BAe-146 research aircraft of the Facility for Airborne Atmospheric Measurements (FAAM) operated over Niger during the winter Special Observation Period of the African Monsoon Multidisciplinary Analysis project (AMMA SOP0/DABEX). Particle size, morphology, and composition were assessed using single-particle analysis by analytical scanning and transmission electron microscopy. The aerosol was found to be composed of externally mixed mineral dust and biomass burning particles. Mineral dust consists mainly of aluminosilicates in the form of illite and kaolinite and quartz, accounting for up to 80% of the aerosol number. Fe-rich particles (iron oxides) represented 4% of the particle number in the submicron fraction. Diatoms were found on all the samples, suggesting that emissions from the Bodele depression were also contributing to the aerosol load. Satellite images confirm that the Bodele source was active during the period of investigation. Biomass burning aerosols accounted for about 15% of the particle number of 0.1–0.6 μm diameter and were composed almost exclusively of particles containing potassium and sulfur. Soot particles were very rare. The aspect ratio AR is a measure of particle elongation. The upper limit of the AR value distribution is 5 and the median is 1.7, which suggests that mineral dust particles could be described as ellipsoids whose major axis never exceeds 1.9 × Dp (the spherical geometric diameter). This is consistent with other published values for mineral dust, including the recent Aerosol Robotic Network retrieval results of Dubovik et al. (2006).
Shear viscosity of clays using the fall cone test

A knowledge of shear viscosity is important in understanding the viscous resistance in the dynamic penetration of soils for geotechnical applications such as jacked piles and cone penetrometers. Viscosities of soils with water contents greater than the liquid limit have been investigated using viscometers. There is, however, no standard method to determine shear viscosities of clays at water contents lower than the liquid limit. In this paper, the post failure (critical state) response of fine-grained soils is modelled as if they were visco-plastic fluids. In addition, the theory of the fall cone test, currently used to interpret the index and strength properties of fine-grained soils, is re-evaluated to discern the viscous drag as the cone penetrates the soil. This re-evaluation shows that the shear viscosities of clays at liquidity indices less than 1·5 can be estimated from a continuous record of time-cone penetration depth data. Fall cone test results on kaolin show that the shear viscosity decreases .
THE VISUAL PERCEPTION OF THE CIRCLE IN THEMATIC MAPS/EXPERIMENTAL RESULTS

The circle is a valuable and useful map symbol. However, traditional and popular methods of designing and using the circle to show quantitative data in thematic maps create erroneous impressions in the minds of map readers in two ways. First, the map reader is unable to discern small variations in circle sizes and second, viewers have difficulties in making quantitatively accurate comparisons of the areas of different size circles. This results in a universal and inherent inaccuracy in the visual perception of relative quantities. These shortcomings can be rectified by employing at all times range-graded circles, varying in size according to an experimentally derived key, and by incorporating within the map an appropriate legend, including as many circle size differences as are found in the map environment. This is true for open, black, or gray circles, regardless of selected variations in base maps. These findings provide guidelines for those who seek to use most effectively circles in thematic maps. Le .
Intra‐seasonal variability of wintertime temperature over East Asia

There has been a profound warming over East Asia during the winter months (November through to March) over the past few decades. The goal of this study is to address the question of whether the daily temperature has become more variable in conjunction with this warming by using observed temperature data obtained from 155 Chinese and Korean stations. Prior to the analysis, the annual cycle is removed to obtain daily temperature anomalies for each winter for each station. Results show that the intra‐seasonal variance generally decreases, implying that the daily temperatures are becoming less variable. Considering all stations as a whole, the rate of change is −0.49°C2 per decade (equivalent to −3.59% per decade). The changes are more robust in the northeastern portion of China. In contrast, there are no dominant trends for the skewness coefficients, except for clear negatively skewed trends in northeastern China. These results are consistent with an increase in the number of extremely cold events. Over the region, the frequency of low‐temperature extremes (as low as below minus two standard deviations) increases at a rate of change of 0.26 days per decade, significant at the 95% confidence level. Both the Siberian high and Arctic oscillation (AO) exert a notable influence on the temperature variance. Intra‐seasonal variance of the Siberian high and AO are significantly correlated with the temperature variance, whereas the seasonal mean state of the AO affects the temperature variance by modulating the high‐frequency components of the Siberian high. The intra‐seasonal variance of the Siberian high tends to decline at a rate of change of −10.7% per decade, significant at the 99% level; meanwhile, the mean wintertime AOs have strengthened in the last few decades. These two climate features together make a considerable contribution to the changes in intra‐seasonal temperature variance in East Asia. Copyright © 2004 Royal Meteorological Society
Spatiotemporal gradients in aerosol radiative forcing and heating rate over Bay of Bengal and Arabian Sea derived on the basis of optical, physical, and chemical properties

[1] Spatiotemporal heterogeneity in aerosol radiative forcing and heating rate have been studied over Bay of Bengal and Arabian Sea during premonsoon (March–May 2006) using aerosol optical depth (AOD), total mass, aerosol chemical composition, and radiative transfer model. Mean 0.5 μm AOD over Bay of Bengal and Arabian Sea is 0.36 and 0.25, respectively. Water-soluble aerosols, sea salt, and mineral dust constitute ∼98% of total aerosol mass while black carbon aerosols contribute ≤2% over the two oceanic regions. Sensitivity tests reveal that (1) curvature effect in AOD spectra has insignificant impact in modifying the aerosol radiative forcing and heating rate and (2) the net Earth-atmosphere energy content shows minor differences when aerosol vertical profiles are used. Over Bay of Bengal the average aerosol forcing is estimated to be −12.0, −22.4, and 10.4 W m−2 at the top of the atmosphere (TOA), at the surface (SFC), and in atmosphere (ATM), respectively. The average aerosol radiative forcing is less negative over Arabian Sea and is −10.5, −15.8, and 5.3 W m−2 at TOA, SFC, and ATM, respectively. Aerosol radiative forcing decreases in magnitude from north to south over Bay of Bengal whereas an opposite trend is noteworthy over Arabian Sea. The average atmospheric heating rate over Bay of Bengal is ∼0.3 K/d, a factor of 2 higher than that over Arabian Sea. Furthermore, ATM warming and associated heating rate are the lowest compared to earlier results as scattering aerosols are dominant during premonsoon (March–May). These results have implications to the assessment of regional and seasonal climate impacts.
The effect of orographic gravity waves on Antarctic polar stratospheric cloud occurrence and composition

[1] A seasonal analysis of the relationship between mesoscale orographic gravity wave activity and polar stratospheric cloud (PSC) composition occurrence around the whole of Antarctica is presented. Gravity wave variances are derived from temperature measurements made with the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) Global Positioning System Radio Occultation (GPS-RO) satellites. Data from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument onboard the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite are used to determine the PSC composition class distribution and spatial volume. The results show intermittent large wave activity above the Antarctic Peninsula which is coincident with large volumes of H2O ice PSCs. These ice PSC volumes advect downstream, where increases in nitric acid trihydrate (NAT) PSC volumes occur, supporting the mountain wave seeding hypothesis. During winter 2007 in the latitude range 60°S–70°S, near the edge of the vortex and where temperatures are close to PSC formation thresholds, 30% of all PSCs are attributable to orographic gravity waves. In the separate composition classes, around 50% of both H2O ice PSCs and a high NAT number density liquid–NAT mixture class of PSCs are due to these waves. While we show that planetary waves are the major determinant of PSC presence at temperatures close to the NAT formation threshold, we also demonstrate the important role of mesoscale, intermittent orographic gravity wave activity in accounting for the composition and distribution of PSCs around Antarctica.
SUSPENSOIDS IN NEW YORK CITY'S DRINKING WATER RESERVOIRS: TURBIDITY APPORTIONMENT 1

ABSTRACT: The technique of individual particle analysis conducted by scanning electron microscopy interfaced with automated X‐ray microanalysis (IPA/SAX) was used to characterize suspended particulate matter in New York City's drinking water reservoirs and their tributaries. The study covered a two year period and involved analyses of more than 300 samples. The particle cross sectional area per unit volume (PAV), or area concentration, was measured to account for the observed turbidity, a representation of light scattering property of the studied medium. A simple linear model with a nearly zero intercept was able to explain more than 85 percent of the variation in the measured turbidity. Moreover, the particle assemblage was categorized into generic particle types with distinctive geochemical or geological origins. Thus, PAV compositions in terms of particle types could be apportioned into turbidity components based on the model. Inorganic tripton, dominated by aluminosilicate (clay) and silicate of nonbiological nature, was found to be the major turbidity causing constituent in most cases. With the exception of one reservoir where organic detritus was significant, the predicted inorganic particle turbidity agreed with the measured turbidity within experimental error.
Microbial colonisation associated with conventional and self-ligating brackets: a systematic review

Background: Decalcification and gingivitis caused by plaque accumulation around brackets are common iatrogenic effects of fixed appliances. The influence of conventional versus self-ligating bracket design on microbial colonisation is unknown. Objective: To assess the levels of microbial colonisation associated with conventional and self-ligating brackets. Search sources: Three databases were searched for publications from 2009 to 2021. Data selection: Randomised controlled trials comparing levels of microbial colonisation before and during treatment with conventional and self-ligating brackets were assessed independently and in duplicate. Data extraction: Data were extracted independently by two authors from the studies that fulfilled the inclusion criteria. Risk of bias assessments were made using the revised Cochrane risk of bias tool for randomized trials. The quality of the included studies was assessed using the Critical Appraisal Skills Programme Checklist. Results: A total of 11 randomised controlled trials were included in this systematic review. Six of the studies were found to be at low risk of bias and five presented with some concerns. The studies were considered moderate to high quality. Five trials reported no statistically significant difference in microbial colonisation between bracket types. The remaining studies showed mixed results, with some reporting increased colonisation of conventional brackets and others increased colonisation of self-ligating brackets. The heterogeneity of study methods and outcomes precluded meta-analysis. Conclusion: Of the 11 studies included in this systematic review, five found no differences in colonisation between conventional and self-ligating brackets. The remaining studies showed mixed results. The evidence is inconclusive regarding the association between bracket design and levels of microbial colonisation.
Effect of Adding Nanofibers into Sunflower ( Helianthus annuus ) Oil on Oil Viscosity

The significant effect of the addition of very small proportions of nanofibres and nano-particulates on the physical and mechanical properties of solid materials has been long observed and described. The effect of addition of electrospun fibres on the physical properties of liquid has not been so widely examined. In this paper, the effect of the addition of polyvinyl alcohol (PVOH), and zein nanofibers in sunflower ( Helianthus annuus ) oil on its viscosity was observed and quantified. For a given amount of material, a trend of increasing effectiveness was found as fibre diameter reduced. The addition of 0.01% (by mass) of fibre increased the kinematic viscosity of oil samples by 15%. The presence of fibre in oil was confirmed by light microscopy whilst the size of the fibres was measured by the analysis of scanning electron microscope images (SEM). This phenomenon of a low concentration of nanofibers significantly increasing viscosity may find practical applications as a foodstuff thickener.
Gypsy Pilot Site Crosswell Seismic Data Processing

Crosswell seismic surveys were conducted in a multi-well setup at the Gypsy Pilot Site in Oklahoma for reservoir characterization. Three well pairs (Well #1 #7, Well #5 #7, and Well #1 #5) in a triangle pattern were selected for this processing study. Reservoir Connectivity Mapping (RCM), velocity tomographic inversion, and crosswell seismic migration were performed between the three well pairs. The RCM results show good reservoir sand connectivity between well pairs, Well #5 #7 and Well #1 #5, but no reservoir sand channel connectivity between well pair Well #1 #7. The velocity tomograms show a continuous low velocity zone (sand channel) between well pairs of Well #7 #5 and Well #5 #1. In well pair Well #7 #1, the tomogram shows a local low velocity area (sand channel) between the two wells and is not intercepted by any of the wells. Migration sections overlaid the velocity tomograms between the three well pairs mapped the boundary and shape of the sand channel very well.
Hyperspectral image classification using spectral histograms and semi-supervised learning

In this paper, an algorithm that extracts regional texture information by computing spectral difference histograms over window extents in hyperspectral images is presented. The spectral angle distance is used as the spectral metric and different window sizes are explored for computing the histogram. The histograms are used in a semi-supervised learning framework that uses both labeled and unlabeled samples for training the support vector machine classifier, which is then tested with unlabeled samples. Results are presented with real and synthetic hyperspectral images. The method performs well with high spatial resolution images. The algorithm performs well under different noise levels.
Tsunami generation by horizontal displacement of ocean bottom

Tsunami generation by an earthquake is generally modeled by water surface displacement identical to the vertical deformation of ocean bottom due to faulting. The effect of horizontal deformation is usually neglected. However, when the tsunami source is on a steep slope and the horizontal displacement is large relative to the vertical displacement, the effect becomes significant. We show this for two recent earthquakes which generated much larger tsunamis than expected from seismic waves. In the case of the 1994 June 2 Java, Indonesia, earthquake, the focal mechanism was a very shallow dipping thrust and the source was near a very steep trench slope. In the case of the 1994 Nov. 14 Mindoro, Philippines, earthquake, strike-slip faulting extended from ocean to land perpendicular to the coast line. In both cases, we found that the horizontal motion of slope had an important contribution to the tsunami generation.
Aerosol temporal characteristics and its impact on shortwave radiative forcing at a location in the northeast of India

[1] Measurements of aerosol optical depth (AOD) and mass concentration of composite and black carbon (BC) aerosols made with collocated instruments over Dibrugarh in Northeast India are used to estimate the aerosol radiative forcing for the period June 2008 to May 2009. AOD shows seasonal variation with maximum in premonsoon (0.69 ± 0.13 at 500 nm in March 2009) and minimum in the retreating monsoon (0.08 ± 0.01 at 500 nm in October 2008). Angstrom coefficients α and β are highest in monsoon and premonsoon season and are lowest in premonsoon and retreating monsoon, respectively. The size segregated mass concentration is minimum in the monsoon season for all the three modes nucleation, accumulation, and coarse and maximum in winter for accumulation and coarse and in premonsoon for nucleation mode. The BC mass concentration is highest 16.3 ± 1.4 μg m−3 in winter and lowest 3.4 ± 0.9 μg m−3 in monsoon. The estimated aerosol radiative forcing of the atmosphere, using Optical Properties of Aerosols and Clouds (OPAC) outputs as inputs for Santa Barbara Discrete Ordinate Atmospheric Radiative Transfer (SBDART), is maximum in premonsoon followed by that in winter and minimum in retreating monsoon. Negative forcing is observed at the surface, whereas the top of the atmosphere (TOA) forcing is nearly zero in retreating monsoon and is negative in rest of the seasons. The forcing efficiency and heating rate were highest during winter and premonsoon, respectively.
Atmospheric 14CO observations and their use for estimating carbon monoxide removal rates

Atmospheric {sup 14}CO can be used as a tracer of the global tropospheric hydroxyl radical (OH) concentration, which is responsible for the destruction of many trace gas species. {sup 14}CO is produced throughout the Earth`s atmosphere by a {sup 14}N neutron capture reaction followed by hot atom oxidation. It subsequently follows the pathway of any other CO molecule and is thus removed from the atmosphere by OH oxidation. From the isotopic information it is also possible to elucidate the histories of CO from otherwise identical air masses. Results from global sampling campaigns are presented which establish the northern hemisphere (NH) latitudinal dependence and seasonal extremes of this trace constituent. The authors used the Lawrence Livermore National Laboratory two-dimensional chemistry/transport model to predict {sup 14}CO temporal and spatial distributions, keeping in mind the importance of reasonable simulations for validating the accuracy of atmospheric models in general. The measured {sup 14}CO latitudinal gradient in the NH is consistent with results from previous campaigns in the southern hemisphere, which reveal lower values than predicted; vertical gradients within the troposphere are similarly exaggerated in model simulations. Differences between model output and observations, which are of the order of 25% and the likely sources ofmore » error are discussed. The authors also examine the difference in {sup 14}CO between the hemispheres and estimate this to be between 15 and 25%, with higher levels in the NH. 27 refs., 6 figs.« less