Miracle-dz/UniFAR-FTUs huggingface dataset:
Synthesis of particulate and extracellular carbon by phytoplankton at the marginal ice zone in the

Large phytoplankton biomass accumulates during ice-edge blooms in Arctic waters, where taxa such as diatoms or the prymnesiophyte Phaeocystis pouchetii usually dominate. Based on characteristics from temperate phytoplankton, we hypothesized that in Barents Sea waters, a larger fraction of primary production would be extracellular (for synthesis of colonial mucilage) during periods of dominance by P. pouchetii as opposed to periods when diatoms dominated. This alternation of P. pouchetii and diatoms would affect the relationship between the particulate and dissolved carbon pools in the upper water column of the marginal ice zone (MIZ). Results presented in this paper do not support this hypothesis. Although P. pouchetii contributed strongly to the extracellular carbon pool (mucilage and dissolved organic carbon, DOC) during an ice-edge bloom in May 1993, arctic diatoms contributed an equal amount of exuded carbon. Three process stations visited along a north-south transect in the MIZ in the Barents Sea, presented between 36% and 55% of the primary production as extracellular carbon, defined as labeled organic matter which passes through a Whatman GF/C filter. No difference in the carbon allocation between diatom- and P. pouchetii-rich phytoplankton was observed in these stations. In contrast, the station located in ice-free waters had 18% of primary production in the extracellular fraction. These results (1) highlight similar carbon allocation for diatom- and P. pouchetii-dominated phytoplankton in surface waters of the Barents Sea during the spring and/or ice-edge bloom at the MIZ and (2) suggest that polar phytoplankton may be stronger producers of extracellular carbon, and possibly DOC, than previously thought.
Experimental evidence of size effect in soil cracking

Results of an experimental study on the formation of crack patterns during drying of a soil paste are presented. The objective is to ascertain whether fracture mechanics plays a significant role in explaining the process of formation and propagation of cracks during drying of soils due to changes in environmental conditions such as temperature and humidity. The experiments consist of five geometrically similar rectangular specimens in two series of different thicknesses, subjected to drying conditions in an environment-controlled laboratory. Cracking initiates shortly before the soil reaches a near-solid quasi-brittle consistency. Although crack initiation can be explained by classical soil mechanics effective stress theory, crack development and propagation appear to be energy-driven. The results prove that cracking stress does depend on the size of the specimen and suggest that fracture mechanics might be applicable to soil cracking, at least in the context of the present research. Fracture toughness of.
Assessing Effects of Small Dams on Stream Flow and Water Quality in an Agricultural Watershed

Small dams and associated reservoirs have notable effects on soil and water dynamics in prairie streams. In this study, we developed a simulation module of small dams in the soil and water assessment tool (SWAT) to evaluate their long-term effects on stream flow and water quality at a watershed scale. To overcome the challenges in characterizing small storage and short retention time in small reservoir routing, concepts of equivalent reservoir storage and equivalent reservoir discharge are applied by which the average daily storage and daily discharge of the small reservoirs are calculated. Accordingly, the sediment deposition and nutrient abatement within the reservoir are computed using available SWAT routines. The effects of small dams in reduction of daily peak flow, sediment, and nutrient loads at the watershed outlet are obtained by summing the effects of all small dams within the watershed considering both reservoir and channel processes. The model is applied to the 74.6-km(2) South Tobacco Creek watershed located in Southern Manitoba of Canada. A total of 26 small dams exist in the watershed with surface area ranging from 0.002 to 0.492 km(2) and storage capacity from 3,380 to 642,000 m(3). The simulation results show that the combined effect of these small dams can reduce daily peak flow by 0-14% at the watershed outlet depending on climate and initial reservoir storage conditions. The estimated average annual sediment, total nitrogen and total phosphorus reductions at the watershed outlet are about 4.51, 3.59, and 2.96%, respectively. However, the on-site effects of individual small dams are much higher depending on its size, location, shape, drainage area, and land use compositions in the contribution area. The simulation results also show that snowmelt-flooding events have higher reduction amounts but lower relative reduction rates compared to rainfall storm events and the back-flood small dams have greater impact on sediment, nitrogen, and phosphorous abatement followed by multipurpose small dams and dry dams in the study watershed. (C) 2014 American Society of Civil Engineers.
Overconsolidation in agricultural soils. I. Compression and consolidation behavior of remolded and structured soils

The identification of meaningful physical indicators of soil quality is an important part of characterizing the present state of our soil resources. A study was undertaken with the main objective of examining the compressive behavior of remolded (saturated only) and structurally intact (variable degrees of saturation including saturated) solum horizons sampled from an agricultural region in southwestern Ontario, Canada. The measured compression lines for the majority of soils showed significant convergence as C c , the slope of the virgin compression line (VCL), increased with initial void ratio (e 0 ) and preconsolidation stress (σ c ). The degree of saturation affected C c mostly through its influence on σ c . Strength gain with progressive desorption was most apparent in nonplastic soils with more than a minimum content of structure stabilizing substances (transient strengthening) and in plastic soils with higher e 0 values. The widely adopted compaction paradigm derived from compression of sieved aggregates (i.e., constant C c and VCL displacement to higher void ratios for a given stress with progressive desorption) was found to hold only for soils with relatively uniform e 0 and weaker grades of structure. Samples identified as highly overcon-solidated (mostly subsoils) had their measured VCL displaced below the normal compression line (NCL) at σ c , which occurred when the void ratio difference between the NCL at unit stress and e 0 exceeded 0.36. Factors contributing to subsoil overconsolidation were believed to be mostly natural, including secondary compression and soil dessication. A pedotransfer function based on VCL reconstruction and σ c estimation is proposed for assessing the degree of overconsolidation in agricultural soils located in this part of Ontario.
GEMSTONES FROM VIGNA BARBERINI AT THE PALATINE HILL (ROME, ITALY)*

This study investigates 25 gemstones (23 intaglios and two undecorated cabochon, used between the third quarter of the first century ad and the second century ad) found in the archaeological excavations performed at ‘Vigna Barberini’, in the north-east sector of the Palatine Hill in Rome. The analytical results obtained by means of SR-XRD, Raman micro-spectroscopy and PIXE measurements provided, in a totally non-destructive mode, unambiguous characterization of the gemstones. The collection from Vigna Barberini consists of two colourless chalcedonies, 11 carnelians, one sard, three Cr-bearing chalcedonies, two nicoli, two orange jaspers, one heliotrope, one almandine garnet, one peridote and one lapis lazuli. Given the lack of analytical data discriminating between different sources, the worldwide occurrence of all these gemstones makes it difficult to reconstruct preferential routes for their commercial trade. However, the methodological approach followed for this research should be of help for the identification of discrimination parameters for provenance investigation.
Local‐time‐dependent low‐altitude ion spectra deduced from TWINS ENA images

In this paper, we analyze Two Wide‐angle Imaging Neutral‐atom Spectrometers (TWINS) stereo observations of energetic neutral atoms (ENAs) produced from the low altitude emission (LAE) region during the interval 1130–1146 UT on 6 April 2010. Geometrical calculations determine the geophysical locations of pixels at or near the LAE limb and the associated uncertainties. For our event, the two TWINS imagers observed a broad (8.4–9.2 h wide in magnetic local time (MLT)) region of LAEs on the opposing limb, possibly containing an ion boundary near dusk. The most intense LAEs were detected in a narrow range of magnetic latitude (67°–74°) and pitch angle (112°–116°). We implement a simplified thick‐target approximation (TTA) to obtain ion spectra from TWINS LAEs and perform a validation study using a conjunction of the TWINS‐observed LAE crescents with a simultaneous NOAA 17 polar‐orbit pass slightly west of the TWINS LAEs. Since TTA is limited to the brightest portion of LAEs, we apply our analysis for pixels with at least 30% of the peak value. TWINS ion spectra are calculated for individual pixels spanning several hours of MLT. The spectra exhibit a pronounced local time dependence. For more westward MLT (and more equatorward latitude), there is a shift toward spectra that are more energetic and peaked. This spatial dependence is consistent with ion drift theory and previous observations. The peaked LAE‐derived ion spectra of 6 April 2010 are notably different than those observed during much weaker disturbances, but are consistent with LAE observations from similar activity levels. These results demonstrate that with proper caution in interpreting the results, TWINS ENA imaging resolves MLT‐dependent (and to a limited extent, latitude‐dependent) low‐altitude ion spectral shape information, simultaneously across a broad range of MLT. This study advances previous results that considered much coarser MLT structure in LAEs and augments previous statistical spectral analysis of in situ data.
Empirical calibration of the silica–Ca‐tschermak’s–anorthite (SCAn) geobarometer

The pressure‐sensitive equilibrium among anorthite, quartz and the Ca‐tschermak component in clinopyroxene (CaAl2SiO6; CaTs), CaAl2SiOCpx6+SiOQtz2=CaAl2Si2OPl8 (SCAn) ,can be used as a geobarometer in granulites with the proper assemblage, and has been calibrated using mineral composition data from partial melting experiments of natural assemblages and from phase equilibrium experiments on the end‐member CMAS system. The experimental data cover the P–T range 4–32 kbar and 900–1400 °C. Linear least‐squares regression analysis of the experimental data resulted in the following empirical expressions for pressure in terms of composition and temperature: P= 5.066 [±0.760]+ 1300 [±800]T −lnK276 [±16] ·T [±2.5 kbar]orP= 6.330 [±0.116]−lnK301 [±9]·T [±1.0 kbar] ,where K= aPlAn aCpxCaTs . The first equation incorporates an enthalpy term, but is less accurate than the second equation, in which the enthalpy of reaction is ignored. Application of these expressions to natural and experimental equilibrium mineral assemblages demonstrates that the empirical barometers are applicable over a wide range of pressures (≥4 kbar), temperatures (≥700 °C) and bulk compositions (Mg#≥32.5).
Modeling the forest cover loss in Democratic Republic of the Congomethods development and application at national scale

The Democratic Republic of the Congo (DRC) hosts 50% of Congo Basin dense forests, the world’s second largest tropical forest which plays a major role in regulating the CO2 fluxes between the Earth surface and the atmosphere. Satellite Earth observation technology is the most efficient way to monitor deforestation and forest degradation taking place in DRC. Pixel- and object-based satellite image processing methods have, however, their own assumptions leading to discrepancies that have to be consolidated to ensure the credibility and the transparency of forest cover change estimates from remote sensing. This thesis simulated future forest cover losses for the whole of the DRC from 2005 to 2035 at 1-km spatial resolution using neural network-based modeling fed by spatially-explicit variables. These included human population distribution and multimodal accessibility to major towns and big villages. The former variable was obtained by disaggregating coarse scale population data available at the third administrative-level. The latter was modeled using a functional approach of the transportation network instead of a single proximity to roads and rivers such as previously modeled by most land-cover change models. The developed forest cover loss model was calibrated using land-cover maps from years 2000-2005 and validated with a land-cover map from the year 2010. The consolidated national annual rate of gross deforestation between 2000 and 2005 corresponded to 0.29%±0.05%. About 70% of these changes were found at locations lying within a daily journey from and to the nearest major town or big village, i.e., 7 hours. Simulations under a proposed forest conservation scenario indicated that the DRC will likely remain a high forested and low deforested country if mitigation actions are undertaken. In turn, a business-as-usual scenario demonstrated that the DRC’s human population will at least double in 2035, leading to a total area of forest cover loss corresponding to13.5% of the forest area in 2005 and an annual rate of forest cover change of about 0.48% between 2005 and 2035. Findings from this thesis highlighted the need for long-term and strategic land-use planning policies in DRC to conciliate economic and agriculture development, infrastructure building, and population growth with a sustainable use of the forest resources, by especially taking into account the regional context of Congo Basin countries.
Impacts of climate change on soil moisture and evapotranspiration in reconstructed watersheds in northern Alberta, Canada

This study aims at developing a generalized understanding of the sensitivity of soil moisture patterns in reconstructed watersheds, in northern Alberta, to changes in the projected precipitation in the twenty‐first century. The GSDW model is applied to three watersheds using climate scenarios generated using daily precipitation and air temperature output from a global climate model (CGCM3), under A2 and B1 emission scenarios, to simulate the corresponding soil moisture. CGCM3 results indicate an increase in the mean annual temperature for Fort McMurray, Alberta of 3·3 (A2) and 2·4 °C (B1), and an increase in the predicted annual precipitation of 34% (A2) and 8·6% with A2 and B1 emission scenarios, respectively. The GSDW model is used, along with onsite historical data, to downscale A2 and B1 emission scenarios and to evaluate the future hydrological performance of the designated watersheds with respect to soil moisture deficit and actual evapotranspiration using a probabilistic framework. The forecasted maximum soil moisture deficit values based on A2 and B1 emission scenarios are expected to decrease compared to those based on the current, largely because of the expected increase in precipitation rates, associated with an expected increase in evapotranspiration. Copyright © 2011 John Wiley & Sons, Ltd.
Automatic Pseudo-invariant Feature Extraction for the Relative Radiometric Normalization of Hyperion Hyperspectral Images

A new relative radiometric normalization approach is presented based on the spectral profile shape of hyperspectral data. We calculate the spectral similarity value of pixels at the same location using spectral angle mapping. The cumulative moving average and its differential values are used to determine the appropriate number of pseudo-invariant features automatically. Band-by-band linear regression of the pseudo-invariant features is used to refine the radiometric normalization results iteratively. We tested the algorithm using six Hyperion data subset images. The proposed method yielded stable results with similar or better performance than other methods for all test sites, when assessed by visual inspection and quantitative analysis.
An assessment of the dendrochronological potential of two Podocarpus species

Within southern Africa, the socio-economic consequences of droughts are often enormous. For an understanding of the future implications of these droughts an understanding of the variation of the range of possible climates is required. At present regional data sets do not extend back for more than 100 years. Since all climate projections are based on this very limited data set, there are obvious limits to the probable accuracy of estimates. It is therefore important to develop other methods for establishing longer records. Within South Africa, Podocarpus species have been at the centre of dendrochronological research for the past 20 years with many claims for a relationship between ring width and certain climate variables. In the present study, the dendrochronological potential of Podocarpus sp. is re-evaluated. The primary objective is to ascertain whether cross-dating and chronology development are possible for Podocarpus sp. Even though whole-trunk cross-sections were used in the analysis of the 14 trees examined, a combination of poorly defined, locally absent and converging rings, combined with lobate growth, makes cross-dating an impossible task. These results suggest that future dendrochronological research using Podocarpus species is not justifiable, especially since whole-trunk cross-sections have to be used in the analysis and suitable specimens of Podocarpus sp. are rare and endangered.
Impact of sympathetic nervous system activity on post-exercise flow-mediated dilatation in humans

Transient reduction in vascular function following systemic large muscle group exercise has previously been reported in humans. The mechanisms responsible are currently unknown. We hypothesised that sympathetic nervous system activation, induced by cycle ergometer exercise, would contribute to post-exercise reductions in flow-mediated dilation (FMD). Ten healthy male subjects (28±5years) undertook two 30 minute sessions of cycle exercise at 75% HRmax. Prior to exercise, individuals ingested either a placebo or an α 1 -adrenoreceptor blocker (Prazosin; 0.05mg.kg -1 ). Central hemodynamics, brachial artery shear rate (SR) and blood flow profiles were assessed throughout each exercise bout and in response to brachial artery FMD, measured prior to, immediately after, and 60-minutes post-exercise. Cycle exercise increased both mean and antegrade SR ( P <0.001) with retrograde SR also elevated under both conditions ( P <0.001). Pre-exercise FMD was similar on both occasions, and significantly reduced (27%) immediately following exercise in the placebo condition (t-test, P =0.03). In contrast, FMD increased (37%) immediately following exercise in the Prazosin condition (t-test, P =0.004, interaction effect P =0.01). Post-exercise FMD remained different between conditions after correction for baseline diameters preceding cuff deflation and also post-deflation shear rate. No differences in FMD or other variables were evident 60-minutes following recovery. Our results indicate that sympathetic vasoconstriction competes with endothelium-dependent dilator activity to determine post-exercise arterial function. These findings have implications for understanding the chronic impacts of interventions, such as exercise training, which affect both sympathetic activity and arterial shear stress.
Stable carbon isotopic compositions of light hydrocarbons over the western North Pacific and implication for their photochemical ages

[1] Light hydrocarbons collected over the western North Pacific in canisters during an oceanographic cruise in May 1999 were analyzed for the mixing ratios and the stable carbon isotopic compositions (δ13C). Their mixing ratios decreased during the passage of a warm front. By contrast, they increased after the passage of a cold front. The δ13C values of ethane were found to be in a range of −26 to −19‰ and to be systematically heavier when the mixing ratios (range of 1.7–0.6 ppbv) became lower. The δ13C values of ethane over the open ocean generally showed heavier values than those previously reported in the source regions, suggesting an isotopic fractionation during a long-range atmospheric transport. In contrast, δ13C values of i- and n-butanes varied in a wide range (−37 to −16‰ and −37 to −21‰, respectively); however, their averaged values are comparative to the isotopic source compositions. Likewise, no systematic relationships were found between the mixing ratios and the δ13C values of the butane isomers. For n-butane the observed relationship was substantially different from that predicted by kinetic isotope effect by the reaction with OH radicals probably due to the contribution of effective mixing process. From the changes in the δ13C values for ethane and n-butane the averaged photochemical ages were calculated to be 49 ± 26 days and 2 ± 6 days, respectively. The difference in the estimated ages is attributed to the different reactivity of hydrocarbons. The average ages for n-butane were found to be consistent with numbers of days, which the air mass took for the transport from the continent to the sampling site over the ocean, on the basis of backward trajectory analysis. This study suggests that the photochemical ages are useful for assessing the importance of recent emission in the marine atmosphere.
Shallow magnetic inclinations in the Cretaceous Valle Group, Baja California: remagnetization, compa

Paleomagnetic data from Albian to Turonian sedimentary rocks on Cedros Island, Mexico (28.2° N, 115.2° W) support the interpretation that Cretaceous rocks of western Baja California have moved farther northward than the 3° of latitude assignable to Neogene oblique rifting in the Gulf of California. Averaged Cretaceous paleomagnetic results from Cedros Island support 20 ± 10° of northward displacement and 14 ± 7° of clockwise rotation with respect to cratonic North America. Positive field stability tests from the Vizcaino terrane substantiate a mid-Cretaceous age for the high-temperature characteristic remanent magnetization in mid-Cretaceous strata. Therefore coincidence of characteristic magnetization directions and the expected Quaternary axial dipole direction is not due to post mid-Cretaceous remagnetization. A slump test performed on internally coherent, intrabasinal slump blocks within a paleontologically dated olistostrome demonstrates a mid-Cretaceous age of magnetization in the Valle Group. The in situ high-temperature natural remanent magnetization directions markedly diverge from the expected Quaternary axial dipole, indicating that the characteristic, high-temperature magnetization was acquired prior to intrabasinal slumping. Early acquisition of the characteristic magnetization is also supported by a regional attitude test involving three localities in coherent mid-Cretaceous Valle Group strata. Paleomagnetic inclinations in mudstone are not different from those in sandstone, indicating that burial compaction did not bias the results toward shallow inclinations in the Vizcaino terrane.